U.S. patent application number 09/929533 was filed with the patent office on 2002-03-07 for packaging and interconnection of contact structure.
This patent application is currently assigned to Advantest Corp.. Invention is credited to Jones, Mark R., Khoury, Theodore A..
Application Number | 20020027444 09/929533 |
Document ID | / |
Family ID | 23081806 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020027444 |
Kind Code |
A1 |
Jones, Mark R. ; et
al. |
March 7, 2002 |
Packaging and interconnection of contact structure
Abstract
A packaging and interconnection of a contact structure formed of
a contact structure made of conductive material and formed on a
contact substrate through a micro-fabrication process, a contact
pad connected to contact substrate and provided at the bottom
surface of the contact substrate, a printed circuit board (PCB) pad
provided on a printed circuit board (PCB) substrate to be
electrically connected with the contact pad, a conductive member
for connecting the contact pad the PCB pad, an elastomer provided
under the contact substrate for allowing flexibility in the
interconnection and packaging of the contact structure, and a
support structure provided between the elastomer and the PCB
substrate for supporting the contact structure, contact substrate
and elastomer.
Inventors: |
Jones, Mark R.; (Mundelein,
IL) ; Khoury, Theodore A.; (Chicago, IL) |
Correspondence
Address: |
Yasuo Muramatsu
MURAMATSU & ASSOCIATES
Suite 225
7700 Irvine Center Drive
Irvine
CA
92618
US
|
Assignee: |
Advantest Corp.
|
Family ID: |
23081806 |
Appl. No.: |
09/929533 |
Filed: |
August 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09929533 |
Aug 13, 2001 |
|
|
|
09282506 |
Mar 31, 1999 |
|
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Current U.S.
Class: |
324/756.04 |
Current CPC
Class: |
G01R 3/00 20130101; H01R
4/04 20130101; G01R 1/06744 20130101; H01R 13/2414 20130101 |
Class at
Publication: |
324/754 |
International
Class: |
G01R 031/02 |
Claims
What is claimed is:
1. A packaging and interconnection of a contact structure,
comprising: a contact structure made of conductive material and
formed on a contact substrate through a micro-fabrication process,
said contact structure having a horizontal portion one end of which
is formed on said base portion, and a contact portion vertically
formed on another end of said horizontal portion; a contact pad
formed on a bottom surface of the contact substrate and
electrically connected to the contact structure through a via hole
and a contact trace; a contact target provided on a printed circuit
board (PCB) substrate to be electrically connected with the contact
pad on the contact substrate through a conductive member.
2. A packaging and interconnection of a contact structure as
defined in claim 1, further comprising: an elastomer provided under
said contact substrate for allowing flexibility in said
interconnection and packaging; and a support structure provided
under said elastomer for supporting said contact structure, said
contact substrate and said elastomer; wherein said conductive
member is a bonding wire for electrically connecting an upper
surface of the contact pad and the contact target.
3. A packaging and interconnection of a contact structure as
defined in claim 1, wherein said contact substrate is a silicon
substrate on which said contact structure is directly formed
through said photolithography process.
4. A packaging and interconnection of a contact structure as
defined in claim 1, wherein said contact substrate is a dielectric
substrate on which said contact structure is directly formed
through said photolithography process.
5. A packaging and interconnection of a contact structure as
defined in claim 1, wherein said contact target is provided on a
printed circuit board (PCB) substrate.
6. A packaging and interconnection of a contact structure,
comprising: a contact structure made of conductive material and
formed on a contact substrate through a micro-fabrication process,
said contact structure having a horizontal portion, one end of
which being formed on the contact substrate, and a contact portion
vertically formed on another end of said horizontal portion; a
contact pad formed on a bottom surface of the contact substrate and
electrically connected to the contact structure through a via hole
and a contact trace; a printed circuit board (PCB) pad provided on
a printed circuit board (PCB) substrate to be electrically
connected with said contact pad; a single layer lead for
electrically connecting the contact pad provided at the bottom
surface of the contact substrate and the PCB pad; an elastomer
provided under said contact substrate for allowing flexibility in
said interconnection and packaging; and a support structure
provided between said elastomer and said PCB substrate for
supporting said contact structure, said contact substrate and said
elastomer.
7. A packaging and interconnection of a contact structure as
defined in claim 6, wherein said PCB substrate is made of glass
epoxy resin or ceramics.
8. A packaging and interconnection of a contact structure as
defined in claim 6, wherein said PCB substrate is a multi-layer
printed circuit board.
9. A packaging and interconnection of a contact structure as
defined in claim 6, wherein said support structure is made of
ceramic, molded plastic or metal.
10. A packaging and interconnection of a contact structure as
defined in claim 6, wherein said single layer lead is formed in a
tape automated bonding (TAB) structure to be used in the packaging
and interconnection.
11. A packaging and interconnection of a contact structure as
defined in claim 6, wherein one end of said single layer lead is
connected to said PCB pad through a conductive bump.
12. A packaging and interconnection of a contact structure as
defined in claim 11, wherein said conductive bump is a solder ball
which reflows by application of heat to electrically connect said
other end of said single layer lead and said PCB pad.
13. A packaging and interconnection of a contact structure as
defined in claim 11, wherein said conductive bump is a conductive
polymer bump or a compliant bump to electrically connect said other
end of said single layer lead and said PCB pad.
14. A packaging and interconnection of a contact structure as
defined in claim 6, wherein one end of said single layer lead is
connected to said PCB pad through a conductive polymer.
15. A packaging and interconnection of a contact structure as
defined in claim 14, wherein said conductive polymer is a
conductive adhesive, conductive film, conductive paste or
conductive particles.
16. A packaging and interconnection of a contact structure as
defined in claim 14, wherein said conductive polymer is a
conductive elastomer including an anisotropic conductive adhesive,
anisotropic conductive film, anisotropic conductive paste or
anisotropic conductive particles to electrically connect said other
end of said contact trace and said PCB pad.
17. A packaging and interconnection of a contact structure,
comprising: a contact structure made of conductive material and
formed on a contact substrate through a micro-fabrication process,
said contact structure having a horizontal portion, one end of
which being formed on the contact substrate, and a contact portion
vertically formed on another end of said horizontal portion; a
contact pad formed on a bottom surface of the contact substrate and
electrically connected to the contact structure through a via hole
and a contact trace; a printed circuit board (PCB) pad provided on
a printed circuit board (PCB) substrate to be electrically
connected with said contact pad; a double layer lead for
electrically connecting the contact pad provided at the bottom
surface of the contact substrate and the PCB pad; an elastomer
provided under said contact substrate for allowing flexibility in
said interconnection and packaging; and a support structure
provided between said elastomer and said PCB substrate for
supporting said contact structure, said contact substrate and said
elastomer.
18. A packaging and interconnection of a contact structure as
defined in claim 17, wherein said PCB substrate is made of glass
epoxy resin or ceramics.
19. A packaging and interconnection of a contact structure as
defined in claim 17, wherein said PCB substrate is a multi-layer
printed circuit board.
20. A packaging and interconnection of a contact structure as
defined in claim 17, wherein said support structure is made of
ceramic, molded plastic or metal.
21. A packaging and interconnection of a contact structure as
defined in claim 17, wherein said double layer lead is formed in a
tape automated bonding (TAB) structure to be used in the packaging
and interconnection.
22. A packaging and interconnection of a contact structure as
defined in claim 17, wherein one end of said double layer lead is
connected to said PCB pad through a conductive bump.
23. A packaging and interconnection of a contact structure as
defined in claim 22, wherein said conductive bump is a solder ball
which reflows by application of heat to electrically connect said
other end of said single layer lead and said PCB pad.
24. A packaging and interconnection of a contact structure as
defined in claim 22, wherein said conductive bump is a conductive
polymer bump or a compliant bump to electrically connect said other
end of said single layer lead and said PCB pad.
25. A packaging and interconnection of a contact structure as
defined in claim 17, wherein one end of said double layer lead is
connected to said PCB pad through a conductive polymer.
26. A packaging and interconnection of a contact structure as
defined in claim 25, wherein said conductive polymer is a
conductive adhesive, conductive film, conductive paste or
conductive particles.
27. A packaging and interconnection of a contact structure as
defined in claim 25, wherein said conductive polymer is a
conductive elastomer including an anisotropic conductive adhesive,
anisotropic conductive film, anisotropic conductive paste or
anisotropic conductive particles to electrically connect said other
end of said contact trace and said PCB pad.
28. A packaging and interconnection of a contact structure as
defined in claim 17, wherein one end of said double layer lead is
formed of an upper lead and a lower lead to be respectively
connected to corresponding PCB pads provided on said PCB
substrate.
29. A packaging and interconnection of a contact structure as
defined in claim 28, wherein said upper lead and said lower lead
are respectively connected to corresponding PCB pads provided on
said PCB substrate through corresponding conductive bumps.
30. A packaging and interconnection of a contact structure as
defined in claim 28, wherein said upper lead and said lower lead
are respectively connected to corresponding PCB pads provided on
said PCB substrate through corresponding conductive polymers.
31. A packaging and interconnection of a contact structure,
comprising: a contact structure made of conductive material and
formed on a contact substrate through a micro-fabrication process,
said contact structure having a horizontal portion, one end of
which being formed on the contact substrate, and a contact portion
vertically formed on another end of said horizontal portion; a
contact pad formed on a bottom surface of the contact substrate and
electrically connected to the contact structure through a via hole
and a contact trace; a printed circuit board (PCB) pad provided on
a printed circuit board (PCB) substrate to be electrically
connected with said contact pad; a triple layer lead for
electrically connecting the contact pad provided at the bottom
surface of the contact substrate and the PCB pad; an elastomer
provided under said contact substrate for allowing flexibility in
said interconnection and packaging; and a support structure
provided between said elastomer and said PCB substrate for
supporting said contact structure, said contact substrate and said
elastomer.
32. A packaging and interconnection of a contact structure as
defined in claim 31, wherein said PCB substrate is made of glass
epoxy resin or ceramics.
33. A packaging and interconnection of a contact structure as
defined in claim 31, wherein said PCB substrate is a multi-layer
printed circuit board.
34. A packaging and interconnection of a contact structure as
defined in claim 31, wherein said support structure is made of
ceramic, molded plastic or metal.
35. A packaging and interconnection of a contact structure as
defined in claim 31, wherein said triple layer lead is formed in a
tape automated bonding (TAB) structure to be used in the packaging
and interconnection.
36. A packaging and interconnection of a contact structure as
defined in claim 31, wherein one end of said triple layer lead is
connected to said PCB pad through a conductive bump.
37. A packaging and interconnection of a contact structure as
defined in claim 36, wherein said conductive bump is a solder ball
which ref lows by application of heat to electrically connect said
other end of said single layer lead and said PCB pad.
38. A packaging and interconnection of a contact structure as
defined in claim 36, wherein said conductive bump is a conductive
polymer bump or a compliant bump to electrically connect said other
end of said single layer lead and said PCB pad.
39. A packaging and interconnection of a contact structure as
defined in claim 31, wherein one end of said triple layer lead is
connected to said PCB pad through a conductive polymer.
40. A packaging and interconnection of a contact structure as
defined in claim 39, wherein said conductive polymer is a
conductive adhesive, conductive film, conductive paste or
conductive particles.
41. A packaging and interconnection of a contact structure as
defined in claim 39, wherein said conductive polymer is a
conductive elastomer including an anisotropic conductive adhesive,
anisotropic conductive film, anisotropic conductive paste or
anisotropic conductive particles to electrically connect said other
end of said contact trace and said PCB pad.
42. A packaging and interconnection of a contact structure as
defined in claim 31, wherein one end of said triple layer lead is
formed of an upper lead, an intermediate lead, and a lower lead to
be respectively connected to corresponding PCB pads provided on
said PCB substrate.
43. A packaging and interconnection of a contact structure as
defined in claim 42, wherein said upper lead, said intermediate
lead, and said lower lead are respectively connected to
corresponding PCB pads provided on said PCB substrate through
corresponding conductive bumps.
44. A packaging and interconnection of a contact structure as
defined in claim 42, wherein said upper lead, said intermediate
lead, and said lower lead are respectively connected to
corresponding PCB pads provided on said PCB substrate through
corresponding conductive polymers.
45. A packaging and interconnection of a contact structure,
comprising: a contact structure made of conductive material and
formed on a contact substrate through a micro-fabrication process,
said contact structure having a horizontal portion, one end of
which being formed on the contact substrate, and a contact portion
vertically formed on another end of said horizontal portion; a
contact pad formed on a bottom surface of the contact substrate and
electrically connected to the contact structure through a via hole
and a contact trace; a connector for establishing electrical
connection with said contact pad; a conductive lead for
electrically connecting the contact pad provided at the bottom
surface of the contact substrate and the connector; an elastomer
provided under said contact substrate for allowing flexibility in
said interconnection and packaging; and a support structure
provided under said elastomer for supporting said contact
structure, said contact substrate, said elastomer and said
connector.
46. A packaging and interconnection of a contact structure as
defined in claim 45, wherein said contact substrate is a silicon
substrate on which said contact structure is directly formed
through said photolithography process.
47. A packaging and interconnection of a contact structure as
defined in claim 45, wherein said contact substrate is a dielectric
substrate on which said contact structure is directly formed
through said photolithography process.
48. A packaging and interconnection of a contact structure as
defined in claim 45, wherein said contact trace is made of
conductive material and formed through either a deposition,
evaporation, sputtering or plating process.
49. A packaging and interconnection of a contact structure as
defined in claim 45, wherein said support structure is made of
ceramic, molded plastic or metal.
50. A packaging and interconnection of a contact structure as
defined in claim 45, wherein said conductive lead has a plurality
of vertically aligned leads to be received by said connector.
51. A packaging and interconnection of a contact structure as
defined in claim 45, wherein said conductive lead has a plurality
of vertically aligned leads formed in a tape automated bonding
(TAB) structure to be used in the packaging and
interconnection.
52. A packaging and interconnection of a contact structure,
comprising: a contact structure made of conductive material and
formed on a contact substrate through a micro-fabrication process,
said contact structure having a horizontal portion, one end of
which being formed on said contact substrate, and a contact portion
vertically formed on another end of said horizontal portion; a
contact pad formed on a bottom surface of the contact substrate and
electrically connected to the contact structure through a via hole
and a contact trace; first and second printed circuit board (PCB)
pads provided on a printed circuit board (PCB) substrate to be
electrically connected with said contact structure; a first lead
for electrically connecting the contact trace provided at the upper
surface of the contact substrate; a second lead for electrically
connecting the contact pad provided at the bottom surface of the
contact substrate and the PCB pad; an elastomer provided under said
contact substrate for allowing flexibility in said interconnection
and packaging; and a support structure provided between said
elastomer and said PCB substrate for supporting said contact
structure, said contact substrate and said elastomer.
Description
FIELD OF THE INVENTION
[0001] This invention relates to an electronic packaging and
interconnection of a contact structure, and more particularly, to
an electronic packaging and interconnection for mounting a contact
structure on a probe card or equivalent thereof which is used to
test semiconductor wafers, semiconductor chips, packaged
semiconductor devices or printed circuit boards and the like with
increased accuracy, density and speed.
BACKGROUND OF THE INVENTION
[0002] In testing high density and high speed electrical devices
such as LSI and VLSI circuits, high performance probe contactors or
test contactors must be used. The electronic packaging and
interconnection of a contact structure of the present invention is
directed to the application of testing and burn-in testing of
semiconductor wafers and dies, but not limited to such applications
and is inclusive of testing and burn-in test of packaged
semiconductor devices, printed circuit boards and the like.
However, for the convenience of explanation, the present invention
is described in the following mainly with reference to a probe card
to be used in semiconductor wafer testing.
[0003] In the case where semiconductor devices to be tested are in
the form of a semiconductor water, a semiconductor test system such
as an IC tester is usually connected to a substrate handler, such
as an automatic wafer prober, to automatically test the
semiconductor wafer. Such an example is shown in FIG. 1 in which a
semiconductor test system has a test head which is ordinarily in a
separate housing and electrically connected to the test system
through a bundle of cables. The test head and the substrate handler
are mechanically connected with one another and the semiconductor
wafers to be tested are automatically provided to a test position
of the test head by the substrate handler such as a wafer
prober.
[0004] On the test head, the semiconductor wafer to be tested is
provided with test signals generated by the semiconductor test
system. The resultant output signals from the semiconductor wafer
under test are transmitted to the semiconductor test system wherein
they are compared with expected data to determine whether IC
circuits (chips) on the semiconductor wafer function correctly or
not.
[0005] As shown in FIGS. 1 and 2, a test head 100 and a substrate
handler 400 are connected with each other through an interface
component 140. The interface component 140 includes a performance
board 120 which is typically a printed circuit board having
electric circuit connections unique to a test head's electrical
footprint, such as coaxial cables, pogo-pins and connectors. The
test head 100 includes a large number of printed circuit boards 150
which correspond to the number of test channels (tester pins) of
the semiconductor test system. Each of the printed circuit boards
150 has a connector 160 to receive therein a corresponding contact
terminal 121 of the performance board 120.
[0006] In the example of FIG. 2, a "frog" ring 130 is mounted on
the performance board 120 to accurately determine the contact
positions relative to the substrate handler 400 such as a wafer
prober. The frog ring 130 has a large number of contact pins 141
formed, for example, by ZIF connectors or pogo-pins, connected to
the contact terminals 121, through coaxial cables 124.
[0007] FIG. 2 further shows a structural relationship between the
substrate handler 400, the test head 100 and the interface
component 140 when testing a semiconductor wafer. As shown in FIG.
2, the test head 100 is placed over the substrate handler 400 and
mechanically and electrically connected to the substrate handler
through the interface component 140. In the substrate handler 400,
a semiconductor wafer 300 to be tested is mounted on a chuck 180. A
probe card 170 is provided above the semiconductor wafer 300 to be
tested. The probe card 170 has a large number of probe contactors
(contact structures) 190, such as cantilevers or needles, to
contact with circuit terminals or contact targets or contact pads
in the IC circuit of the semiconductor wafer 300 under test.
[0008] Electrical terminals or contact receptacles of the probe
card 170 are electrically connected to the contact pins 141
provided on the frog ring 130. The contact pins 141 are also
connected to the contact terminals 121 of the performance board 120
via the coaxial cables 124 where each contact terminal 121 is
connected to the printed circuit board 150 of the test head 100.
Further, the printed circuit boards 150 are connected to the
semiconductor test system main frame through the cable bundle 110
having several hundreds of cables therein.
[0009] Under this arrangement, the probe contactors (needles or
cantilevers) 190 contact the surface of the semiconductor wafer 300
on the chuck 180 to apply test signals to the IC chips on the
semiconductor wafer 300 and receive the resultant signals of the IC
chips from the wafer 300. The resultant output signals from the
semiconductor wafer 300 under test are compared with the expected
data generated by the semiconductor test system to determine
whether the IC chips in the semiconductor wafer 300 properly
perform the intended functions.
[0010] FIG. 3 is a bottom view of the probe card 170 of FIG. 2. In
this example, the probe card 170 has an epoxy ring on which a
plurality of probe contactors 190 called needles or cantilevers are
mounted. When the chuck 180 mounting the semiconductor wafer 300
moves upward in FIG. 2, the tips of the cantilevers 190 contact the
contact targets such as contact pads or bumps on the wafer 300. The
ends of the cantilevers 190 are connected to wires 194 which are
further connected to transmission lines (not shown) formed in the
probe card 170. The transmission lines in the probe card 170 are
connected to a plurality of electrodes 197 which further contact
the pogo pins 141 of FIG. 2.
[0011] Typically, the probe card 170 is structured by a multi-layer
of polyimide substrates having ground planes, power planes, signal
transmission lines in many layers. As is well known in the art,
each of the signal transmission lines is designed to have a
characteristic impedance such as 50 ohms by balancing the
distributed parameters, i.e., dielectric constant and magnetic
permeability of the polyimide, inductances and capacitances of the
signal paths within the probe card 170. Thus, the signal
transmission lines are impedance matched to achieve a high
frequency transmission bandwidth to the wafer 300 under test. The
signal transmission lines transmit a small current during a steady
state of a pulse signal and a large peak current during a
transition state of the device's outputs switching. For removing
noise, capacitors 193 and 195 are provided on the probe card 170
between the power and ground planes.
[0012] An equivalent circuit of the probe card 170 is shown in
FIGS. 4A-AE to explain the limitations of bandwidth in the
conventional probe card technology. As shown in FIGS. 4A and 4B,
the signal transmission line on the probe card 170 extends from the
electrode 197, the strip line (impedance matched line) 196, the
wire 194 and the needle (cantilever) 190. Since the wire 194 and
needle 190 are not impedance matched, these portions function as an
inductor L in the high frequency band as shown in FIG. 4C. Because
of the overall length of the wire 194 and needle 190 is around
20-30 mm, the value of the inductor L is not trivial, resulting in
the significant frequency limitation in testing a high frequency
performance of a device under test.
[0013] Other factors which limit the frequency bandwidth in the
probe card 170 reside in both power and ground needles shown in
FIGS. 4D and 4E. If a power line can provide large enough currents
to the device under test, it will not seriously limit the
operational bandwidth in testing the device. However, because the
series connected wire 194 and needle 190 for supplying the power to
the device under test are equivalent to the inductors as shown in
FIG. 4D, which impede the high speed current flow in the power
line. Similarly, because the series connected wire 194 and needle
190 for grounding the power and signals are equivalent to the
inductors as shown in FIG. 4E, the high speed current flow is
impeded by the wire 194 and needle 190.
[0014] Moreover, the capacitors 193 and 195 are provided between
the power line and the ground line to secure a proper performance
of the device under test by filtering out the noise or surge pulses
on the power lines. The capacitors 193 have a relatively large
value such as 10 .mu.F and can be disconnected from the power lines
by switches if necessary. The capacitors 195 have a relatively
small capacitance value such as 0.01 .mu.F and fixedly connected
close to the DUT (device under test). Since these capacitors serve
as high frequency decoupling on the power lines, which also impede
the high speed current flow in the signal and power lines.
[0015] Accordingly, the probe contactors noted above are limited to
the frequency bandwidth of approximately 200 MHz which is
insufficient to test recent semiconductor devices. It is
considered, in the industry, that the frequency bandwidth equal to
the tester's capability, which is currently on the order of 1 GHz
or higher, will be necessary in the near future. Further, it is
desired in the industry that a probe card is capable of handling a
large number of semiconductor devices, especially memory devices,
such as 32 or more, in a parallel fashion at the same time to
increase test throughput.
[0016] To meet the next generation test requirements noted above,
the inventors of this application has provided a new concept of
contact structure in the U.S. application Ser. No. 09/099,614
"Probe Contactor Formed by Photolithography Process" filed Jun. 19,
1998. The contact structure is formed on a silicon or dielectric
substrate through a photolithography process. FIGS. 5 and 6A-6C
show the contact structure in the above noted application. In FIG.
5, all of the contact structures 30 are formed on a silicon
substrate 20 through the same photolithography process. The silicon
substrate 20 having the contact structures 30 may be mounted on a
probe card such as shown in FIGS. 2 and 3. When the semiconductor
wafer 300 under test moves upward, the contact structures 30
contact with corresponding contact targets (electrodes or pads) 320
on the wafer 300.
[0017] The contact structure 30 on the silicon substrate 20 can be
directly mounted on a probe card such as shown in FIG. 3, or molded
in a package, such as a traditional IC package having leads, so
that the package is mounted on a probe card. In the above noted
patent application by the inventors, such technologies of packaging
and interconnection of the contact structure 30 with respect to the
probe card or equivalent thereof is not described.
SUMMARY OF THE INVENTION
[0018] Therefore, it is an object of the present invention to
provide a packaging and interconnection of a contact structure with
respect to a probe card or equivalent thereof to be used -in
testing a semiconductor wafer, packaged LSI and the like.
[0019] It is another object of the present invention to provide a
packaging and interconnection of a contact structure with respect
to a probe card or equivalent thereof to achieve a high speed and
high frequency operation in testing a semiconductor wafer, packaged
LSI and the like.
[0020] It is a further object of the present invention to provide a
packaging and interconnection of a contact structure with respect
to a probe card or equivalent thereof wherein the packaging and
interconnection is formed at a bottom surface of the substrate
mounting the contact structure.
[0021] It is a further object of the present invention to provide a
packaging and interconnection of a contact structure which is
established through a bonding wire, a single layer tape automated
bonding (TAB), or a multi-layer tape automated bonding (TAB) at the
bottom surface of the substrate mounting the contact structure.
[0022] It is a further object of the present invention to provide a
packaging and interconnection of a contact structure which is
established between a contact pad formed at the bottom surface of
the substrate mounting the contact structure and an electric
connector.
[0023] It is a further object of the present invention to provide a
packaging and interconnection of a contact structure which is
established between a contact pad formed at the bottom surface of
the substrate mounting the contact structure and an interconnect
pad of a printed circuit board through a solder bump.
[0024] It is a further object of the present invention to provide a
packaging and interconnection of a contact structure which is
established between a contact pad formed at the bottom surface of
the substrate mounting the contact structure and an interconnect
pad of a printed circuit board through a conductive polymer.
[0025] In the present invention, an electronic packaging and
interconnection of a contact structure to be used in a probe card
or equivalent thereof to test semiconductor wafers, semiconductor
chips, packaged semiconductor devices or printed circuit boards and
the like. The packing and interconnection is established between a
contact pad formed at the bottom surface of the substrate mounting
the contact structure and various types of connection means on the
probe card. The contact pad at the bottom is connected to the
contact structure at an upper surface of the substrate through a
via hole and a contact trace both of which are provided on the
substrate.
[0026] In one aspect of the present invention, a packaging and
interconnection of a contact structure is comprised of: a contact
structure made of conductive material and formed on a contact
substrate through a photolithography process wherein the contact
structure has a base portion vertically formed on the contact
substrate, a horizontal portion, one end of which being formed on
the base portion, and a contact portion vertically formed on
another end of the horizontal portion; a contact pad formed on a
bottom surface of the contact substrate and electrically connected
to the contact structure through a via hole and a contact trace; a
contact target provided on a printed circuit board (PCB) substrate
to be electrically connected with the contact pad on the contact
substrate through a conductive bump or polymer.
[0027] In another aspect of the present invention, a packaging and
interconnection of a contact structure is comprised of: a contact
structure made of conductive material and formed on a contact
substrate through a photolithography process wherein the contact
structure has a base portion vertically formed on the contact
substrate, a horizontal portion, one end of which being formed on
the base portion, and a contact portion vertically formed on
another end of the horizontal portion; a contact pad formed on a
bottom surface of the contact substrate and electrically connected
to the contact structure through a via hole and a contact trace; a
contact target provided on a printed circuit board (PCB) substrate
or lead frame to be electrically connected with the contact pad on
the contact substrate through a bonding wire; and a support
structure for supporting the contact structure and the contact
substrate.
[0028] In a further aspect of the present invention, a packaging
and interconnection of a contact structure is comprised of: a
contact structure made of conductive material and formed on a
contact substrate through a photolithography process wherein the
contact structure has a base portion vertically formed on the
contact substrate, a horizontal portion, one end of which being
formed on the base portion, and a contact portion vertically formed
on another end of the horizontal portion; a contact pad formed on a
bottom surface of the contact substrate and electrically connected
to the contact structure through a via hole and a contact trace; a
contact target provided on a printed circuit board (PCB) substrate
or lead frame to be electrically connected with the contact pad on
the contact substrate through a tape automated bonding (TAB) lead;
an elastomer provided under the contact substrate for allowing
flexibility in the interconnection and packaging; and a support
structure for supporting the contact structure, the contact
substrate and the elastomer.
[0029] In a further aspect of the present invention, a connector is
provided to receive the TAB lead connected to the contact pad to
establish electrical connection therebetween. In a further aspect
of the present invention, a conductive bump is provided between the
TAB lead connected to the contact pad and the PCB pad to establish
electrical connection thereamong. In a further aspect of the
present invention, a conductive polymer is provided between the TAB
lead connected to the contact pad and the PCB pad to establish
electrical connection thereamong.
[0030] In a further aspect of the present invention, the
interconnection and packaging of the contact structure is
established through a bonding wire between the contact pad on the
contact substrate and a contact target. In a further aspect of the
present invention, the interconnection and packaging of the contact
structure is established through a single layer TAB lead extending
between the contact pad on the contact substrate and a contact
target. In a further aspect of the present invention, the
interconnection and packaging of the contact structure is
established through a double layer TAB lead extending between the
contact pad on the contact substrate and a contact target. In a
further aspect of the present invention, the interconnection and
packaging of the contact structure is established through a triple
layer TAB lead extending between the contact pad on the contact
substrate and a contact target.
[0031] According to the present invention, the packaging and
interconnection has a very high frequency bandwidth to meet the
test requirements in the next generation semiconductor test
technology. The packaging and interconnection is able to mount the
contact structure on a probe card or equivalent thereof by
electrically connecting therewith through the bottom surface of the
contact substrate mounting the contact structure. Moreover, because
of the relatively small number of overall components to be
assembled, the interconnection and packaging of the present
invention can be fabricated with low cost and high reliability as
well as high productivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic diagram showing a structural
relationship between a substrate handler and a semiconductor test
system having a test head.
[0033] FIG. 2 is a schematic diagram showing an example of detailed
structure for connecting the test head of the semiconductor test
system to the substrate handler.
[0034] FIG. 3 is a bottom view showing an example of the probe card
having an epoxy ring for mounting a plurality of cantilevers as
probe contactors.
[0035] FIGS. 4A-4E are circuit diagrams showing equivalent circuits
of the probe card of FIG. 3.
[0036] FIG. 5 is a schematic diagram showing contact structures
associated with the present invention produced through a
photolithography process.
[0037] FIGS. 6A-6C are schematic diagrams showing examples of
contact structure associated with the present invention formed on a
silicon substrate.
[0038] FIG. 7 is a schematic diagram showing a first embodiment of
the present invention in which the packaging and interconnection is
established between a contact pad provided at a bottom surface of
the contact substrate mounting the contact structure and a PCB
(printed circuit board) pad by a conductive bump.
[0039] FIG. 8 is a schematic diagram showing a modified structure
of the first embodiment of the present invention wherein a
conductive polymer is used between the contact pad and the PCB
pad.
[0040] FIG. 9 is a schematic diagram showing a second embodiment of
the present invention in which the packaging and interconnection is
established by a bonding wire between a contact pad provided at a
bottom surface of the contact substrate mounting the contact
structure and a contact target provided on a probe card or a device
package.
[0041] FIG. 10 is a schematic diagram showing a modified structure
of the second embodiment of the present invention wherein the
contact target is a PCB pad.
[0042] FIG. 11 is a schematic diagram showing a third embodiment of
the present invention in which the packaging and interconnection is
established by a single layer TAB (tape automated bonding) lead
between a contact pad provided at a bottom surface of the contact
substrate mounting the contact structure and a contact target on a
probe card or a device package.
[0043] FIG. 12 is a schematic diagram showing a modified structure
of the third embodiment of the present invention in which a
straight shape TAB lead is incorporated as an interconnection and
packaging member.
[0044] FIG. 13 is a schematic diagram showing a further modified
structure of the third embodiment of the present invention in which
a contact target is a connector.
[0045] FIG. 14 is a schematic diagram showing a further modified
structure of the third embodiment of the present invention in which
a conductive bump is incorporated between the TAB lead and the
contact target as one of interconnection and packaging members.
[0046] FIG. 15 is a schematic diagram showing a further modified
structure of the third embodiment of the present invention in which
a conductive polymer is incorporated between the TAB lead and the
contact target as one of interconnection and packaging members.
[0047] FIG. 16 is a schematic diagram showing a fourth embodiment
of the present invention in which the packaging and interconnection
is established by a double layer TAB (tape automated bonding) lead
between a contact pad provided at a bottom surface of the contact
substrate mounting the contact structure and a contact target on a
probe card or a device package.
[0048] FIG. 17 is a schematic diagram showing a modified structure
of the fourth embodiment of the present invention in which a
straight shape double layer TAB lead is incorporated as an
interconnection and packaging member to be connected to a pair of
contact targets.
[0049] FIG. 18 is a schematic diagram showing a further modified
structure of the fourth embodiment of the present invention in
which a contact target is a connector to be connected with the
double layer TAB lead.
[0050] FIG. 19 is a schematic diagram showing a further modified
structure of the fourth embodiment of the present invention in
which a contact target is a connector to be connected with the
straight shape double layer TAB lead.
[0051] FIG. 20 is a schematic diagram showing a further modified
structure of the fourth embodiment of the present invention in
which a conductive bump is incorporated between the TAB lead and
the contact target as one of interconnection and packaging
members.
[0052] FIG. 21 is a schematic diagram showing a further modified
structure of the fourth embodiment of the present invention in
which a pair of conductive bumps are incorporated between the
double layer TAB lead and the contact targets as interconnection
and packaging members.
[0053] FIG. 22 is a schematic diagram showing a further modified
structure of the fourth embodiment of the present invention in
which a conductive polymer is incorporated between the double layer
TAB lead and the contact target as one of interconnection and
packaging members.
[0054] FIG. 23 is a schematic diagram showing a further modified
structure of the fourth embodiment of the present invention in
which a pair of conductive polymer are incorporated between the
double layer TAB lead and the contact targets as interconnection
and packaging members.
[0055] FIG. 24 is a schematic diagram showing a fifth embodiment of
the present invention in which the packaging and interconnection is
established by a triple layer TAB (tape automated bonding) lead
between a contact pad provided at a bottom surface of the contact
substrate mounting the contact structure and a contact target on a
probe card or a device package.
[0056] FIG. 25 is a schematic diagram showing a modified structure
of the fifth embodiment of the present invention in which a
straight shape triple layer TAB lead is incorporated as one of
interconnection and packaging members to be connected to three
contact targets.
[0057] FIG. 26 is a schematic diagram showing a further modified
structure of the fifth embodiment of the present invention in which
a contact target is a connector to be connected with the triple
layer TAB lead.
[0058] FIG. 27 is a schematic diagram showing a further modified
structure of the fifth embodiment of the present invention in which
a contact target is a connector to be connected with the straight
shape triple layer TAB lead.
[0059] FIG. 28 is a schematic diagram showing a further modified
structure of the fifth embodiment of the present invention in which
a conductive bump is incorporated between the TAB lead and the
contact target as one of interconnection and packaging members.
[0060] FIG. 29 is a schematic diagram showing a further modified
structure of the fifth embodiment of the present invention in which
three conductive bumps are incorporated between the triple layer
TAB lead and the contact targets as interconnection and packaging
members.
[0061] FIG. 30 is a schematic diagram showing a further modified
structure of the fifth embodiment of the present invention in which
a conductive polymer is incorporated between the triple layer TAB
lead and the contact target as one of interconnection and packaging
members.
[0062] FIG. 31 is a schematic diagram showing a further modified
structure of the fifth embodiment of the present invention in which
three conductive polymer are incorporated between the triple layer
TAB lead and the contact targets as interconnection and packaging
members.
[0063] FIG. 32 is a schematic diagram showing a sixth embodiment of
the present invention in which the packaging and interconnection is
established by a single layer TAB (tape automated bonding) lead
between a contact trace provided at an upper surface of the contact
substrate and a first contact target as well as a double layer TAB
lead between a contact pad provided at a bottom surf ace of the
contact substrate and a second contact target.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0064] To establish a packaging and interconnection of a contact
structure directly with a probe card or indirectly with a probe
card through an IC package, examples of FIGS. 6A-6C show basic
three types of electrical path extended from the contact structure
to form such interconnections. FIG. 6A shows an example in which
such an electrical connection is established at the top of the
substrate. FIG. 6B shows an example in which an electrical
connection is established at the bottom of the substrate while FIG.
6C shows an example in which an electrical connection is formed at
the edge of the substrate. Almost any types of existing IC package
design or probe card design can accommodate at least one of the
interconnect types of FIGS. 6A-6C.
[0065] Each of FIGS. 6A-6C include a contact interconnect trace 32
also designated by a which is to establish electrical connection
with a probe card or any intermediate member to a probe card. The
contact structure 30 has vertical portions b and d and a horizontal
beam c and a tip portion e. The tip portion e of the contact
structure 30 is preferably sharpened to achieve a scrubbing effect
when pressed against contact targets 320 such as shown in FIG. 3.
The spring force of the horizontal beam c provides an appropriate
contact force against the contact target 320. An example of
material of the contact structure 30 and the contact trace 32
includes nickel, aluminum, copper and other conductive materials.
The inventors of this application have provided a detailed
description of production process of the contact structure 30 and
the contact interconnect trace 32 on the silicon substrate 20 in
the above noted U.S. application Ser. No. 09/099,614.
[0066] In the present invention, the packaging and interconnection
of a contact structure is directed to the type of structure having
a contact pad 36 provided at a bottom surface of the substrate 20,
i.e., the bottom type contact pad as shown in FIG. 6B. The contact
pad 36 is connected to the contact structure 30 through a via hole
35 and the contact trace 32. The contact structure 30 is formed on
the top surface of the contact substrate 20. Various embodiments of
the present invention on the bottom type packaging and
interconnection will be described with reference to the
drawings.
[0067] FIG. 7 is a schematic diagram showing a first embodiment of
the present invention in which the packaging and interconnection is
established between the contact pad provided at the bottom surface
of the contact substrate mounting the contact structure and a PCB
(printed circuit board) pad by a conductive bump or a conductive
polymer.
[0068] In the first example of FIG. 7, a contact structure 30
formed on a contact substrate 20 is electrically connected to a
contact pad 36 provided at the bottom surface of the contact
substrate 20 through a contact trace 32 and a via hole 35. The
contact structure 30 is formed on the top surface of the contact
substrate 20. The contact pad 36 at the bottom of the contact
substrate 20 is positioned over a print circuit board (PCB)
interconnect pad 38 on a printed circuit board (PCB) 62. A
conductive bump 56 electrically connects the contact pad and the
PCB pad. The contact substrate 20 is a silicon substrate although
other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible.
[0069] Typically, the conductive bump 56 is a solder bump used in a
standard solder ball technology. By the application of the heat,
the conductive bump 56 is reflowed onto the PCB pad 38 for
attachment between the contact pad 36 and the PCB pad 38. Another
example of the conductive bump 56 is a fluxless solder ball used in
a plasma-assisted dry soldering technology. Further examples of
conductive bump will be given later with respect to further
embodiments of the present invention.
[0070] In the example of FIG. 8, a conductive polymer 66 is used
between the contact pad 36 provided at the bottom surface of the
contact substrate 20 and the PCB pad 38 on the PCB substrate 62.
The contact substrate 20 is a silicon substrate although other
types of dielectric substrate, such as glass epoxy, polyimide,
ceramic, and alumina substrates are also feasible. An example of
the conductive polymer 66 is a conductive elastomer which is filled
with conductive wire that extends beyond the surface of the
elastomer. Most conductive polymers are designed to be conductive
between the mating electrodes normally in vertical of angled
directions and not conductive in the horizontal direction. Further
examples of conductive polymer will be given later with respect to
further embodiments of the present invention.
[0071] FIGS. 9 and 10 show a second embodiment of the present
invention wherein the bottom type contact pad is coupled to a lead
frame or a printed circuit board provided, for example, of a probe
card (not shown) or an IC package (not shown) through a bonding
wire. In the first example of FIG. 9, a contact structure 30 formed
on a contact substrate 20 is electrically connected to a contact
pad 36 provided at the bottom surface of the contact substrate 20
via a contact trace 32 and a through hole 35. The contact structure
30 is formed on the top surface of the contact substrate 20. The
contact pad 36 is designed to establish an electrical connection
with contact targets such as a lead frame 45 through various
contact means such as a bonding wire 72. The bonding wire 72 is a
thin wire of 15-25 .mu.m diameter and made, for example, of gold or
aluminum.
[0072] Typically, the contact substrate 20 is a silicon substrate
although other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible. In
the example of FIG. 9, the bonding wire 72 connects the contact pad
36 and the lead frame 45 of, for example, a probe card. The contact
substrate 20 and the lead frame 45 are mounted on a support
structure 52 through, for example, an adhesive (not shown).
[0073] Any wire bonding procedure can be used to establish the
connection between the contact pad 36 and the contact target. The
bonding wire 72 is first bonded to the contact pad 36 of the
contact substrate and spanned to the lead frame 45. The wire 72 is
bonded to the lead frame 45 and is clipped, and the entire process
above is repeated at the next bonding location. The wire bonding is
done with either gold or aluminum wires. Both materials are highly
conductive and ductile enough to withstand deformation during the
bonding steps and still remaining strong and reliable. In the gold
wire bonding, thermo-compression (TC) and thermosonic methods are
typically used. In the aluminum wire bonding, ultrasonic and wedge
bonding methods are typically used.
[0074] In the example of FIG. 10, the contact pad 36 at the bottom
of the contact substrate is connected to a printed circuit board
(PCB) interconnect pad 38 provided on a PCB substrate 62.sub.2
through a bonding wire 72. The PCB substrate 62.sub.2 can be a
probe card such as shown in FIG. 3 or an intermediate circuit
component provided between the contact structure and the probe
card. The PCB substrate is mounted on a support structure 52. The
contact substrate 20 and the support structure 52 are fixed with
one another by, for example, an adhesive (not shown). Similarly,
the PCB substrate 62.sub.2 and the support structure 52 are fixed
with one another by an adhesive (not shown)
[0075] FIGS. 11-15 show a third embodiment of the present invention
wherein the bottom type contact pad is coupled to a contact target
through a single layer lead formed by a tape automated bonding
(TAB) process. In the first example of FIG. 11, the contact
structure 30 formed on a top surface of the contact substrate 20 is
electrically connected to the contact pad 33 at the bottom of the
substrate 20 via the contact trace 32 and the through hole 35. The
contact pad 36 is connected at its bottom surface with a single
layer TAB lead 74 whose other end is also connected to a printed
circuit board (PCB) interconnect pad 38 provided on a PCB substrate
62.
[0076] The contact substrate 20 is mounted on the PCB substrate 62
through an elastomer 42 and a support structure 52.sub.2. The
contact substrate 20, the elastomer 42, the support structure
52.sub.2 and the PCB substrate 62 are fixed with one another by,
for example, an adhesive (not shown). In this example, the TAB lead
74 for connecting the contact pad 36 and the PCB pad 38 has a
gull-wing shape where a gull-wing (lower) portion is bonded to the
PCB pad 38. A support member 54 is provided on the support
structure 52.sub.2 to support the TAB lead 74.
[0077] As noted above, the TAB lead 74 has a gull-wing shape which
is similar to the standard "gull-wing lead" used in a surface mount
technology. Because of the down-ward bent of the gull-wing type TAB
lead 74, a sufficient vertical clearance is achieved at the left
side of FIG. 11 over the contact portion between the PCB pad 38 and
the TAB lead 74. The lead form of the TAB lead 74 (downward bent,
gull-wing lead) may require special tooling to produce the same. A
large number of interconnection between the contact pads and the
PCB pads will be used in an actual application such as
semiconductor device testing, for example several hundred
connections. Thus, such tooling may be standardized for a multiple
of contact pads with given pitch.
[0078] The electrical connections between the contact pad 36 and
the TAB lead 74 and between the TAB lead 74 and the PCB pad 38 will
be established by various bonding technologies including
thermosonic bonding, thermocompression bonding, and ultrasonic
bonding technique. In another aspect, such electrical connections
will be established through a surface mount technology (SMT) such
as using a screen printable solder paste. A soldering process is
carried out based on the reflow characteristics of the solder paste
and other solder materials well known in the art.
[0079] The PCB substrate 62 itself may be a probe card such as
shown in FIG. 3 or provided separately from the probe card, and
mounted directly or indirectly on the probe card. In the former
case, the PCB 62 may make direct contact with an interface of a
semiconductor test system such as an IC tester in a manner shown in
FIG. 2. In the latter case, the PCB substrate 62 is pinned or in
use of a conductive polymer for establishing an electrical contact
to the next level of a contact mechanism on the probe card. Such
types of electrical connection between the PCB substrate 62 and the
probe card through pins or conductive polymer would allow for field
repairability.
[0080] The PCB substrate 62 may be a multiple layer structure which
is capable of providing high bandwidth signals, distributed high
frequency capacitance and integrated high frequency chip capacitors
for power supply decoupling as well as high pin counts (number of
I/O pins and associated signal paths). An example of material of
the PCB 62 is standard high performance glass epoxy resin. Another
example of multi-layer PCB substrate material is ceramic. The
ceramic substrate is expected to minimize mismatch in coefficient
of temperature expansion (CTE) rates during high temperature
applications such as a burn-in test of semiconductor wafers and
packaged IC devices.
[0081] The support structure 52.sub.2 is to establish a physical
strength of the packaging and interconnection of the contact
structure. The support structure 52.sub.2 is made of, for example,
ceramic, molded plastic or metal. The elastomer 42 is to establish
flexibility in the packaging and interconnection of the present
invention to overcome a potential planarization mechanism. The
elastomer 42 also functions to absorb a mismatch in temperature
expansion rates between the contact substrate 20 and the PCB
substrate 62.
[0082] An example of overall length of the signal path from the
contact structure 30, the contact trace 32, the contact pad 36 and
the TAB lead 74 is in the range of several hundred micrometers.
Because of the short path length, the packaging interconnection of
the present invention can be easily operable in a high frequency
band such as several GHz or even higher. Moreover, because of a
relatively small number of overall components to be assembled, the
packaging and interconnection of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0083] FIG. 12 shows another example of the third embodiment of the
present invention. A TAB lead 74.sub.2 is straight and connects the
contact pad 36 at the bottom of the contact substrate 20 to the PCB
pad 38 provided on a printed circuit board (PCB) substrate
62.sub.3. To match the vertical position of the PCB pad 38, the PCB
substrate 62.sub.3 has a raised portion at the left end
thereof.
[0084] The electrical connection between the TAB lead 74.sub.2 and
the PCB pad 38 will be established by a surface mount technology
(SMT) such as using a screen printable solder paste as well as
various other bonding technologies including thermosonic bonding,
thermocompression bonding, and ultrasonic bonding technique.
Because of the significantly small sizes of the components and
signal path lengths involved in the contact structure 30, contact
trace 32, contact pad 36, and the TAB lead 74.sub.2 the example of
FIG. 12 can operate at a very high frequency band, such as several
GHz. Moreover, because of the small number of components involved
and simple structure of the components to be assembled, the
interconnection and packaging of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0085] FIG. 13 shows a further modification of the third embodiment
of the present invention wherein the bottom type contact pad 36 is
coupled to a connector provided on a printed circuit board or other
structure. In the example of FIG. 13, the contact pad 36 provided
at the bottom surface of the contact substrate is connected to a
connector 46 via a single layer TAB lead 74.sub.2. The connector 46
is provided on a support structure 52.sub.4. The contact substrate
20 is a silicon substrate although other types of dielectric
substrate, such as glass epoxy, polyimide, ceramic, and alumina
substrates are also feasible.
[0086] The TAB lead 74.sub.2 has a straight shape as in the example
of FIG. 12. At about the center of FIG. 13, the contact substrate
20 is mounted on the support structure 52.sub.4 through an
elastomer 42. The contact substrate 20, the elastomer 42 and the
support structure 52.sub.4 are attached with one another by, for
example, an adhesive (not shown). The connector 46 may be
mechanically fixed to the support structure 52.sub.4 through an
attachment mechanism (not shown). The end of the TAB lead 74.sub.2
is inserted in a receptacle (not shown) of the connector 46. As is
well known in the art, such a receptacle has a spring mechanism to
provide a sufficient contact force when receiving the end of the
TAB lead 74.sub.2 therein. Between the TAB lead 74.sub.2, and the
support structure 52.sub.4, there is provided a support member 54
to support the TAB lead 74.sub.2 extending between the contact pad
36 and the connector 46. Also well known in the art, an inner
surface of such a receptacle is provided with conductive metal such
as gold, silver, palladium or nickel.
[0087] The connector 46 may be integrated with straight or right
angle pins, which may be connected to the receptacle noted above,
for direct connection to a printed circuit board (PCB). A PCB to
mount the connector 46 thereon can be either solid or flexible. As
is known in the art, a flexible PCB is formed on a flexible base
material and has flat cables therein. Alternatively, the connector
46 may be integrated with a coaxial cable assembly in which a
receptacle is attached to an inner conductor of the coaxial cable
for receiving the end of the TAB lead 74.sub.2, therein. The
connection between the connector 46 and the TAB lead 74.sub.2 or
the support structure 52.sub.4 is not a permanent attachment
method, allowing for field replacement and repairability of the
contact portion.
[0088] Typically, the contact substrate 20 is a silicon substrate
although other types of substrate, such as glass epoxy, polyimide,
ceramic, and alumina substrates are also feasible. The support
structure 52.sub.4 is to establish a physical strength of the
packaging and interconnection of the contact structure. The support
structure 52.sub.4 is made of, for example, ceramic, molded plastic
or metal. The elastomer 42 is to establish flexibility in the
interconnection and packaging of the present invention to overcome
a potential planarization mechanism. The elastomer 42 also
functions to absorb a mismatch in temperature expansion rates
between the contact substrate 20 and a PCB substrate to mount the
connector 46 thereon.
[0089] An example of an overall signal path length from the contact
structure 30, the contact trace 32, the contact pad 36 to the end
of the TAB lead 74.sub.2 is in the range of several hundred
micrometers. Because of the short path length, the interconnection
and packaging of the present invention can be easily operable in a
high frequency band such as several GHz or even higher. Moreover,
because of the lower total number of components to be assembled,
the packaging and interconnection of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0090] FIGS. 14 shows a further example of the third embodiment of
the present invention wherein the bottom type contact pad is
coupled to an interconnect pad provided on a printed circuit board
through a conductive bump. In the example of FIG. 14, a contact
structure 30, a contact trace 32, a via hole 35, and a contact pad
33 are formed on a contact substrate 20. The contact structure 30
is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20. Typically, the contact substrate 20 is a silicon substrate
although other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible. The
contact pad 36 is connected to a PCB (print circuit board) pad 38
provided on a PCB substrate 62 through a conductive bump 56 via a
single layer TAB lead 74.sub.2.
[0091] The TAB lead 74.sub.2 has a straight as in the examples of
FIGS. 12 and 13. The contact substrate 20 is mounted on the PCB
substrate 62 through a support structure 52.sub.2 and an elastomer
42. The contact substrate 20, the elastomer 42, the support
structure 52.sub.2, and the PCB substrate 62 are attached with one
another by, for example, an adhesive (not shown). In FIG. 14,
between the TAB lead 74.sub.2 and the support structure 52.sub.2,
there is provided a support member 54 to support the TAB lead
74.sub.2 extending between the contact pad 36 and the PCB pad
38.
[0092] By the application of the heat, the conductive bump 56 is
reflowed onto the PCB pad 38 for attachment between the TAB lead
74.sub.2 and the PCB pad 38. An example of the conductive bump 56
is a solder bump used in a standard solder ball technology. Another
example of the conductive bump 56 is a fluxless solder ball used in
a plasma-assisted dry soldering technology.
[0093] Further examples of the conductive bump 56 are a conductive
polymer bump and a compliant bump which involve the use of polymer
in the bump. This helps in minimizing planarization problems or CTE
(coefficient of temperature expansion) mismatches in the packaging
and interconnection. There is no reflowing of metal, which prevents
bridging between contact points. The conductive polymer bump is
made of a screen printable conductive adhesive. The compliant bump
is a polymer core bump with a metal coating. The polymer is
typically plated with gold and is elastically compressible. Still
further example of the conductive bump 56 is a bump used in a
controlled collapse chip connection technology in which solder
balls are formed by an evaporation process.
[0094] The PCB substrate 62 itself may be a probe card such as
shown in FIG. 3 or provided separately from the probe card and
mounted directly or indirectly on the probe card. In the former
case, the PCB substrate 62 may make direct contact with an
interface of a semiconductor test system such as an IC tester in
the manner shown in FIG. 2. In the latter case, the PCB substrate
62 is pinned or in use of a conductive polymer for establishing an
electrical contact to the next level. Such types of electrical
connection between the PCB substrate 62 and the probe card through
pins or conductive polymer would allow for field repairability.
[0095] The PCB substrate 62 may be a multiple layer structure which
is capable of providing high bandwidth signals, distributed high
frequency capacitance and integrated high frequency chip capacitors
for power supply decoupling as well as high pin counts (number of
I/O pins and associated signal paths). An example of material of
the PCB substrate 62 is standard high performance glass epoxy
resin. Another example of the material is ceramic which is expected
to minimize mismatch in coefficient of temperature expansion (CTE)
rates during high temperature application such as a burn-in test of
semiconductor wafers and packaged IC devices.
[0096] The support structure 52.sub.2 is to establish a physical
strength of the packaging and interconnection of the contact
structure. The support structure 52.sub.2 is made of, for example,
ceramic, molded plastic or metal. The elastomer 42 is to establish
flexibility in the packaging and interconnection of the present
invention to overcome a potential planarization mechanism. The
elastomer 42 also functions to absorb a mismatch in temperature
expansion rates between the contact substrate 20 and the PCB
substrate 62.
[0097] An example of overall length of the signal path extending
from the contact structure 30, the contact trace 32, the contact
pad 36 and the TAB lead 74.sub.2 is in the range of several hundred
micrometers. Because of the short path length, the interconnection
and packaging of the present invention can be easily operable in a
high frequency band such as several GHz or even higher. Moreover,
because of the lower total number of components to be assembled,
the packaging and interconnection of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0098] FIG. 15 shows a further example of the third embodiment of
the present invention wherein the bottom type contact pad is
coupled to an interconnect pad provided on a printed circuit board
through a conductive polymer. In the example of FIG. 15, a contact
structure 30, a contact trace 32, a via hole 35, and a contact pad
36 are formed on a contact substrate 20. The contact structure 30
is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20. The contact pad 36 is connected to a PCB (print circuit board)
pad 38 provided on a PCB substrate 62 through a TAB lead 74.sub.2
and a conductive polymer 66. Typically, the contact substrate 20 is
a silicon substrate although other types of dielectric substrate,
such as glass epoxy, polyimide, ceramic, and alumina substrates are
also feasible.
[0099] In this example, the TAB lead 74.sub.2 has a straight shape
similar to the examples of FIGS. 12-14. The contact substrate 20 is
mounted on the PCB substrate 62 through a support structure
52.sub.2 and an elastomer 42. The contact substrate 20, the
elastomer 42, the support structure 52.sub.2, and the PCB substrate
62 are attached with one another by, for example, an adhesive (not
shown)
[0100] Most conductive polymers are designed to be conductive
between the mating electrodes normally in vertical of angled
directions and not conductive in the horizontal direction. An
example of the conductive polymer 66 is a conductive elastomer
which is filled with conductive wire that extends beyond the
surface of the elastomer.
[0101] Various other examples of the conductive polymer 66 are
possible such as an anisotropic conductive adhesive, anisotropic
conductive film, anisotropic conductive paste, and anisotropic
conductive particles. The anisotropic conductive adhesive is filled
with conductive particles that do not touch each other. The
conductive path is formed by pressing the adhesive between the two
electrodes at a specific location. The anisotropic conductive film
is a thin dielectric resin filled with conductive particles that do
not touch each other. The conductive path is formed by pressing the
film between the two electrodes at a specific location.
[0102] The anisotropic conductive paste is a screen printable paste
which is filled with conductive particles that do not touch each
other. The conductive path is formed by pressing the paste between
the two electrodes at a specific location. The anisotropic
conductive particle is a thin dielectric resin filled with
conductive particles coated with a very thin layer of dielectric
material to improve isolation. The conductive path is formed by
pressing the particle with enough force to explode the dielectric
coating on the particles, between the two electrodes at a specific
location.
[0103] The PCB substrate 62 itself may be a probe card such as
shown in FIG. 3 or provided separately from the probe card and
mounted directly or indirectly on the probe card. In the former
case, the PCB substrate 62 may make direct contact with an
interface of a semiconductor test system such as an IC tester in
the manner shown in FIG. 2. In the latter case, the PCB substrate
62 is pinned or in use of a conductive polymer for establishing an
electrical contact to the next level. Such types of electrical
connection between the PCB substrate 62 and the probe card through
pins or conductive polymer would allow for field repairability.
[0104] The PCB substrate 62 may be a multiple layer structure which
is capable of providing high bandwidth signals, distributed high
frequency capacitance and integrated high frequency chip capacitors
for power supply decoupling as well as high pin counts (number of
I/O pins and associated signal paths). An example of material of
the PCB substrate 62 is standard high performance glass epoxy
resin. Another example of material is ceramic which is expected to
minimize mismatch in coefficient of temperature expansion (CTE)
rates during high temperature application such as a burn-in test of
semiconductor wafers and packaged IC devices.
[0105] The support structure 52.sub.2 is to establish a physical
strength of the packaging and interconnection of the contact
structure. The support structure 52.sub.2 is made of, for example,
ceramic, molded plastic or metal. The elastomer 42 is to establish
flexibility in the packaging and interconnection of the present
invention to overcome a potential planarization mechanism. The
elastomer 42 also functions to absorb a mismatch in temperature
expansion rates between the contact substrate 20 and the PCB
substrate 62.
[0106] An example of signal path length involved in this packaging
and interconnection is in the range of several hundred micrometers.
Because of the short path length, the packaging and interconnection
of the present invention can be easily operable in a high frequency
band such as several GHz or even higher. Moreover, because of the
lower total number of components to be assembled, the
interconnection and packaging of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0107] FIGS. 16-23 show a fourth embodiment of the present
invention wherein the bottom type contact pad is coupled to a
contact target through a double layer lead formed by a tape
automated bonding (TAB) process. In the first example of FIG. 16, a
contact structure 30 formed on a contact substrate 20 is
electrically connected to a contact pad 36 via a contact trace 32
and a through hole 35. The contact structure 30 is formed on the
upper surface of the contact substrate 20 while the contact pad 36
is formed on the bottom surface of the substrate 20. The contact
pad 36 is connected at its bottom surface with a double layer TAB
lead 76 whose other end is also connected to a printed circuit
board (PCB) interconnect pad 38 provided on a PCB substrate 62.
[0108] The contact substrate 20 is mounted on the PCB substrate 62
through an elastomer 42 and a support structure 52.sub.3. The
contact substrate 20, the elastomer 42, the support structure
52.sub.3 and the PCB substrate 62 are fixed with one another by,
for example, an adhesive (not shown). In this example, the double
layered TAB lead 76 for connecting the contact pad 36 and the PCB
pad 38 has an upper lead A and a lower lead B. A support member
54.sub.2 is provided between the upper lead and the lower lead of
the TAB lead 76.
[0109] The TAB lead 76 has a gull-wing shape which is similar to
the standard "gull-wing lead" lead used in a surface mount
technology. Because of the down-ward bent of the gull-wing type TAB
lead 76, a sufficient vertical clearance is achieved at the left
side of FIG. 16 over the contact portion between the PCB pad 38 and
the TAB lead 76. The lead form of the TAB lead 76 (downward bent,
gull-wing lead) may require special tooling to produce the same.
Since a large number of interconnection between the contact pads
and the PCB pads will be used in an actual application such as
semiconductor device testing, several hundred connections for
example, such tooling may be standardized for a multiple of contact
traces with given pitch.
[0110] The structure of the TAB lead 76 having the tiered leads A
and B establish a low resistance in a signal path because of two
leads running in parallel. This is useful in transmitting a large
current such as in a ground line or a power line of a probe card
for testing a semiconductor device with high speed without
deforming the waveforms of test signals.
[0111] The electrical connections between the contact pad 36 and
the TAB lead 76 and between the TAB lead 76 and the PCB pad 38 will
be established by various bonding technologies including
thermosonic bonding, thermocompression bonding, and ultrasonic
bonding technique. In another aspect, such electrical connections
will be established through a surface mount technology (SMT) such
as using a screen printable solder paste. A soldering process is
carried out based on the reflow characteristics of the solder paste
and other solder materials well known in the art.
[0112] The PCB substrate 62 itself may be a probe card such as
shown in FIG. 3 or provided separately and mounted directly or
indirectly on the probe card. In the former case, the PCB substrate
62 may make direct contact with an interface of a semiconductor
test system such as an IC tester in a manner shown in FIG. 2. In
the latter case, the PCB substrate 62 is pinned or in use of a
conductive polymer for establishing an electrical contact to the
next level of a contact mechanism on the probe card. Such types of
electrical connection between the PCB substrate 62 and the probe
card through pins or conductive polymer would allow for field
repairability.
[0113] The PCB substrate 62 may be a multiple layer structure which
is capable of providing high bandwidth signals, distributed high
frequency capacitance and integrated high frequency chip capacitors
for power supply decoupling as well as high pin counts (number of
I/O pins and associated signal paths). An example of material of
the PCB 62 is standard high performance glass epoxy resin. Another
example of material is ceramic which is expected to minimize
mismatch in coefficient of temperature expansion (CTE) rates during
high temperature application such as a burn-in test of
semiconductor wafers and packaged IC devices.
[0114] The support structure 52.sub.3 is to establish a physical
strength of the packaging and interconnection of the contact
structure. The support structure 52.sub.33, is made of, for
example, ceramic, molded plastic or metal. The elastomer 42 is to
establish flexibility in the packaging and interconnection of the
present invention to overcome a potential planarization mechanism.
The elastomer 42 also functions to absorb a mismatch in temperature
expansion rates between the contact substrate 20 and the PCB
substrate 62.
[0115] An example of overall signal path length extending from the
contact structure 30 to the PCB pad 38 is in the range several
hundred micrometers. Because of the short path length, the
packaging interconnection of the present invention can be easily
operable in a high frequency band such as several GHz or even
higher. Moreover, because of a relatively small number of overall
components to be assembled, the packaging and interconnection of
the present invention can be fabricated with low cost and high
reliability as well as high productivity.
[0116] FIG. 17 shows another example of the fourth embodiment of
the present invention. In this example, a double layered TAB lead
76.sub.2 having upper and lower leads A and B is provided to the
contact pad 36 connected to the contact structure 30. The upper
lead A is provided in an upper and outer position of FIG. 17 than
the lower lead B. The upper lead A is connected to a PCB pad 38 and
the lower lead B is connected to a PCB pad 39. To accommodate the
PCB pads 38 and 39 thereon, a PCB substrate 62.sub.4 is arranged to
have an edge having a larger thickness, i.e., a step, to mount the
PCB pad 38, and an inner portion adjacent to the edge portion
having a smaller thickness to mount the PCB pad 39.
[0117] The electrical connection between the TAB lead 76.sub.2 and
the PCB pads 38 and 39 will be established by a surface mount
technology (SMT) such as using a screen printable solder paste as
well as various other bonding technologies including thermosonic
bonding, thermocompression bonding, and ultrasonic bonding
technique. Because of the significantly small sizes of the
components and signal path lengths involved in the contact
structure 30, contact trace 32, contact pad 36, and the TAB lead
76.sub.2, the example of FIG. 17 can operate at a very high
frequency band, such as several GHz. Moreover, because of the small
number and simple structure of components to be assembled, the
interconnection and packaging of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0118] The structure of the TAB lead 76.sub.2 having the double
layered leads A and B establishes a fan out in the vertical
dimension. This is useful in distributing a signal or power to two
or more paths. Another advantage of the fan out is to increase the
number of contact pads on both the contact substrate and the PCB
substrate. In other words, it is possible to decrease the effective
pitch (distance) between the contact pads.
[0119] FIG. 18 shows a further modification of the fourth
embodiment of the present invention wherein the bottom type contact
pad 36 is coupled to a connector provided on a printed circuit
board or other structure. In the example of FIG. 18, a contact pad
36 connected to the contact structure 30 is connected to a
connector 46.sub.2 through a double layer TAB lead 76.sub.4. The
connector 46.sub.2 is provided on a support structure 52.sub.5.
[0120] Typically, the contact structure 30, contact trace 32,
through hole 35 and the contact pad 36 are formed on the contact
substrate 20 through photolithography processes. The contact
structure 30 is formed on the upper surface of the contact
substrate 20 while the contact pad 36 is formed on the bottom
surface of the substrate 20. The contact substrate 20 is a silicon
substrate although other types of dielectric substrate, such as
glass epoxy, polyimide, ceramic, and alumina substrates are also
feasible.
[0121] The connector 46.sub.2 may be mechanically fixed to the
support structure 52.sub.5, through an attachment mechanism (not
shown). The end of the TAB lead 76.sub.4 is inserted in a
receptacle (not shown) of the connector 46.sub.2. As is well known
in the art, such a receptacle has a spring mechanism to provide a
sufficient contact force when receiving the end of the TAB lead
76.sub.4 therein. Between the upper lead A and the lower lead B of
the double layer TAB lead 76.sub.4, there is provided a support
member 54.sub.2 to support the leads A and B of the TAB lead
76.sub.4 extending between the contact pad 36 and the connector
46.sub.2. Also well known in the art, an inner surface of such
receptacles are provided with conductive metal such as gold,
silver, palladium or nickel.
[0122] The structure of the TAB lead 76.sub.4 having the tiered
leads A and B establish a low resistance in a signal path because
of the two leads. This is useful in transmitting a large current
such as in a ground line or a power line for testing a
semiconductor device with high speed without deforming the
waveforms of the test signals.
[0123] The connector 46.sub.2 may be integrated with straight or
right angle pins, which may be connected to the receptacle noted
above, for direct connection to a printed circuit board (PCB). A
printed circuit board (PCB) to mount the connector 46.sub.2 thereon
can be either solid or flexible. As is known in the art, a flexible
PCB is formed on a flexible base material and has flat cables
therein. Alternatively, the connector 46.sub.2 may be integrated
with a coaxial cable assembly in which a receptacle is attached to
an inner conductor of the coaxial cable for receiving the ends of
the TAB lead 76.sub.4 therein. The connection between the connector
46.sub.2 and the TAB lead 76.sub.4 or the support structure
52.sub.5 is not a permanent attachment method, allowing for field
replacement and repairability of the contact portion.
[0124] Typically, the contact substrate 20 is a silicon substrate
although other types of substrate, such as glass epoxy, polyimide,
ceramic, and alumina substrates are also feasible. The support
structure 52.sub.5, is to establish a physical strength of the
packaging and interconnection of the contact structure. The support
structure 52.sub.5, is made of, for example, ceramic, molded
plastic or metal. The elastomer 42 is to establish flexibility in
the interconnection and packaging of the present invention to
overcome a potential planarization mechanism. The elastomer 42 also
functions to absorb a mismatch in temperature expansion rates
between the contact substrate 20 and a PCB substrate to mount the
connector 46.sub.2 thereon.
[0125] FIG. 19 shows a further modification of the fourth
embodiment of the present invention wherein the bottom type contact
pad 36 is coupled to a connector provided on a printed circuit
board or other structure. In the example of FIG. 19, a contact pad
36 connected to the contact structure 30 is connected to a
connector 46.sub.3 via a double layer TAB lead 76.sub.6. The double
layer TAB 76.sub.6 has an upper lead A and a lower lead B, each of
which is separated from one another at the end. The connector
46.sub.3 is provided on a support structure 52.sub.4.
[0126] The connector 46.sub.3 may be mechanically fixed to the
support structure 52.sub.4 through an attachment mechanism (not
shown). The ends of the leads A and B of the TAB lead 76.sub.6 are
inserted in receptacles (not shown) of the connector 46.sub.3. As
is well known in the art, such a receptacle has a spring mechanism
to provide a sufficient contact force when receiving the end of the
TAB lead 76.sub.6 therein. Between the upper lead A and the lower
lead B of the double layer TAB lead 76.sub.6, there is provided a
support member 54.sub.4 to support the leads A and B.
[0127] The structure of the TAB lead 76.sub.6 having the double
layered leads A and B establishes a fan out in the vertical
dimension. This is useful in distributing a signal or power to two
or more paths. Another advantage of the fan out is to increase the
number of contact pads, i.e., to decrease the effective pitch
(distance) between the contact pads.
[0128] FIG. 20 shows a further example of the fourth embodiment of
the present invention wherein the bottom type contact pad is
coupled to an interconnect pad provided on a printed circuit board
through a conductive bump. In the example of FIG. 20, a contact
structure 30, a contact trace 32, a through hole 35 and a contact
pad 36 are formed on a contact substrate 20. The contact structure
30 is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20.
[0129] Typically, the contact substrate 20 is a silicon substrate
although other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible. The
contact pad 36 at the bottom of the contact substrate 20 is
connected to a PCB (print circuit board) pad 38 provided on a PCB
substrate 62 through a conductive bump 56 through a double layer
TAB lead 76.sub.4.
[0130] The contact substrate 20 is mounted on the PCB substrate 62
through a support structure 52.sub.3 and an elastomer 42. The
contact substrate 20, the elastomer 42, the support structure
52.sub.3, and the PCB substrate 62 are attached with one another
by, for example, an adhesive (not shown). Between the upper lead A
and the lower lead B of the TAB lead 76.sub.4, there is provided
with a support member 54.sub.2 to support the upper and lower leads
A and B.
[0131] By the application of the heat, the conductive bump 56 is
reflowed onto the PCB pad 38 for attachment between the TAB lead
76.sub.4 and the PCB pad 38. An example of the conductive bump 56
is a solder bump used in a standard solder ball technology. Another
example of the conductive bump 56 is a fluxless solder ball used in
a plasma-assisted dry soldering technology.
[0132] Further examples of the conductive bump 56 are a conductive
polymer bump and a compliant bump which involve the use of polymer
in the bump. This helps in minimizing planarization problems or CTE
(coefficient of temperature expansion) mismatches in the packaging
and interconnection. There is no reflowing of metal, which prevents
bridging between contact points. The conductive polymer bump is
made of a screen printable conductive adhesive. The compliant bump
is a polymer core bump with a metal coating. The polymer is
typically plated with gold and is elastically compressible. Still
further example of the conductive bump 56 is a bump used in a
controlled collapse chip connection technology in which solder
balls are formed by an evaporation process.
[0133] The structure of the TAB lead 76.sub.4 having the tiered
leads A and B establish a low resistance in a signal path because
of the two leads. This is useful in transmitting a large current
such as in a ground line or a power line in a probe card for
testing a semiconductor device with high speed without deforming
the waveforms of the test signals.
[0134] FIG. 21 shows a further example of the fourth embodiment of
the present invention. In this example, a double layered TAB lead
76.sub.2 having upper and lower leads A and B are provided to the
contact pad 36 connected to the contact structure 30. The upper
lead A is provided in an upper and outer position than the lower
lead B in FIG. 21. The upper lead A is connected to a PCB pad 38
via a conductive dump 56 and the lower lead B is connected to a PCB
pad 39 via a conductive dump 57. To accommodate the PCB pads 38 and
39 thereon, a PCB substrate 62.sub.3 is arranged to have an edge
having a larger thickness, i.e., a step, to mount the PCB pad 38,
and an inner portion adjacent to the edge portion having a smaller
thickness to mount the PCB pad 39.
[0135] By the application of the heat, the conductive bumps 56 and
57 are reflowed onto the PCB pads 38 and 39 for attachment between
the TAB lead 76.sub.2 and the PCB pads 38 and 39. An example of the
conductive bumps 56 and 57 is a solder bump used in a standard
solder ball technology. Another example of the conductive bumps 56
and 57 is a fluxless solder ball used in a plasma-assisted dry
soldering technology.
[0136] The structure of the TAB lead 76.sub.2 having the double
layered leads A and B establishes a fan out in the vertical
dimension. This is useful in distributing a signal or power to two
or more paths. Another advantage of the fan out is to increase the
number of contact pads, i.e., to decrease the effective pitch
(distance) between the contact pads.
[0137] FIG. 22 shows a further example of the fourth embodiment of
the present invention wherein the bottom type contact pad is
coupled to an interconnect pad provided on a printed circuit board
through a conductive polymer. In the example of FIG. 22, a contact
structure 30, a contact trace 32, a through hole 35, and a contact
tab 33 are formed on a contact substrate 20. The contact structure
30 is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20. Typically, the contact substrate 20 is a silicon substrate
although other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible. The
contact pad 36 is connected to a PCB (print circuit board) pad 38
provided on a PCB substrate 62 through a conductive polymer 66 via
a double layer TAB lead 76.sub.4.
[0138] The contact substrate 20 is mounted on the PCB substrate 62
through a support structure 52.sub.3 and an elastomer 42. The
contact substrate 20, the elastomer 42, the support structure
52.sub.3, and the PCB substrate 62 are attached with one another
by, for example, an adhesive (not shown). Between the upper lead A
and the lower lead B of the TAB lead 76.sub.4, there is provided
with a support member 54.sub.2 to support the upper and lower leads
A and B.
[0139] Most conductive polymers are designed to be conductive
between the mating electrodes normally in vertical of angled
directions and not conductive in the horizontal direction. An
example of the conductive polymer 66 is a conductive elastomer
which is filled with conductive wire that extends beyond the
surface of the elastomer.
[0140] Various other examples of the conductive polymer 66 are
possible such as an anisotropic conductive adhesive, anisotropic
conductive film, anisotropic conductive paste, and anisotropic
conductive particles. The anisotropic conductive adhesive is filled
with conductive particles that do not touch each other. The
conductive path is formed by pressing the adhesive between the two
electrodes at a specific location. The anisotropic conductive film
is a thin dielectric resin filled with conductive particles that do
not touch each other. The conductive path is formed by pressing the
film between the two electrodes at a specific location.
[0141] The anisotropic conductive paste is a screen printable paste
which is filled with conductive particles that do not touch each
other. The conductive path is formed by pressing the paste between
the two electrodes at a specific location. The anisotropic
conductive particle is a thin dielectric resin filled with
conductive particles coated with a very thin layer of dielectric
material to improve isolation. The conductive path is formed by
pressing the particle with enough force to explode the dielectric
coating on the particles, between the two electrodes at a specific
location.
[0142] The structure of the TAB lead 76.sub.4 having the tiered
leads A and B establish a low resistance in a signal path because
of the two leads. This is useful in transmitting a large current
such as in a ground line or a power line in a probe card for
testing a semiconductor device with high speed without deforming
the waveforms of the test signals.
[0143] FIG. 23 shows another example of the fourth embodiment of
the present invention. In this example, a double layered TAB lead
76.sub.2 having upper and lower leads A and B are provided to the
contact pad 36 connected to the contact trace 32 and contact
structure 30. The upper lead A is provided in an upper and outer
position than the lower lead B in FIG. 21. The upper lead A is
connected to a PCB (printed circuit board) pad 38 via a conductive
polymer 66 and the lower lead B is connected to a PCB pad 39 via a
conductive polymer 67. To accommodate the PCB pads 38 and 39
thereon, a PCB substrate 62.sub.3 is arranged to have an edge
having a larger thickness, i.e., a step, to mount the PCB pad 38,
and an inner portion adjacent to the edge portion having a smaller
thickness to mount the PCB pad 39.
[0144] The electrical connection between the TAB lead 76.sub.2 and
the PCB pads 38 and 39 will be established by a surface mount
technology (SMT) such as using a screen printable solder paste as
well as various other bonding technologies including thermosonic
bonding, thermocompression bonding, and ultrasonic bonding
technique.
[0145] The structure of the TAB lead 76.sub.2 having the double
layered leads A and B establishes a fan out in the vertical
dimension. This is useful in distributing a signal or power to two
or more paths. Another advantage of the fan out is to increase the
number of contact pads, i.e., to decrease the effective pitch
(distance) between the contact pads.
[0146] FIGS. 24-31 show a fifth embodiment of the present invention
wherein the bottom type contact pad is coupled to a contact target
through a triple layer lead formed by a tape automated bonding
(TAB) process. In the first example of FIG. 24, the contact
structure 30 formed on a contact substrate 20 is electrically
connected to the contact pad 36 via the contact trace 32 and the
through hole 35. The contact structure 30 is formed on the upper
surface of the contact substrate 20 while the contact pad 36 is
formed on the bottom surface of the substrate 20. The contact pad
36 is connected at its bottom surface with a three layer TAB lead
78 which is also connected to a printed circuit board (PCB)
interconnect pad 38 provided on a PCB substrate 62.
[0147] The contact substrate 20 is mounted on the PCB substrate 62
through an elastomer 42 and a support structure 52.sub.3. The
contact substrate 20, the elastomer 42, the support structure
52.sub.3 and the PCB substrate 62 are fixed with one another by,
for example, an adhesive (not shown). In this example, the triple
layered TAB lead 78 for connecting the contact pad 36 and the PCB
pad 38 has an upper lead A, an intermediate lead B and a lower lead
C. A support member 54.sub.4 is provided between the upper lead A
and the intermediate lead B of the triple layered TAB lead 78. A
support member 54.sub.5 is provided between the intermediate lead B
and the lower lead C of the triple layered TAB lead 78.
[0148] The TAB lead 78 as a whole has a gull-wing shape which is
similar to the standard "gull-wing lead" lead used in a surface
mount technology. Because of the down-ward bent of the gull-wing
type TAB lead 78, a sufficient vertical clearance is achieved at
the left end of FIG. 22 over the contact portion between the PCB
pad 38 and the TAB lead 78. The lead form of the TAB lead 78
(downward bent, gull-wing lead) may require special tooling to
produce the same. Since a large number of interconnection between
the contact trace and the PCB pad will be used in the application
such as semiconductor testing, several hundred connections, such
tooling may be standardized for a multiple of contact traces with
given pitch.
[0149] The structure of the TAB lead 78 having the tiered leads A,
B and C establishes a low resistance and a large current capacity
in a signal path because of the three conductive leads running in
parallel. This is useful in transmitting a large current such as in
a ground line or a power line in a probe card for testing a
semiconductor device with high speed without deforming the
waveforms of test signals.
[0150] FIG. 25 shows another example of the fifth embodiment of the
present invention. In this example, a triple layered TAB lead
78.sub.2 having upper, intermediate and lower leads A, B and C is
provided to the contact pad 36 connected to the contact trace 32,
through hole 35 and contact structure 30. The contact structure 30
is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20.
[0151] The upper lead A is provided in an upper and outer position
of FIG. 25 than the intermediate lead B. The intermediate lead B is
provided in an upper and outer position of FIG. 25 than the lower
lead C. The upper lead A is connected to a PCB pad 38, the
intermediate lead B is connected to a PCB pad 39, and the lower
lead C is connected to a PCB pad 40. To accommodate the PCB pads
38, 39 and 40 thereon, a PCB substrate 62.sub.4 is arranged to have
steps to mount the PCB pads 38, 39 and 40 with different vertical
positions. A support member 54.sub.6 is provided between the upper
lead A and the intermediate lead B and a support member 54.sub.7 is
provided between the intermediate lead B and the lower lead C.
[0152] The electrical connection between the TAB lead 78.sub.2 and
the PCB pads 38, 39 and 40 will be established by a surface mount
technology (SMT) such as using a screen printable solder paste as
well as various other bonding technologies including thermosonic
bonding, thermocompression bonding, and ultrasonic bonding
technique. Because of the significantly small sizes of the
components and signal path lengths involved in the contact
structure 30, contact trace 32, and the TAB lead 78.sub.2, the
example of FIG. 23 can operate at a very high frequency band, such
as several GHz. Moreover, because of the small number and simple
structure of components to be assembled, the interconnection and
packaging of the present invention can be fabricated with low cost
and high reliability as well as high productivity.
[0153] The structure of the TAB lead 78.sub.2 having the triple
layered leads A, B and C establishes a fan out in the vertical
dimension of the TAB lead. This is useful in distributing a signal
or power to two or more paths. Another advantage of the fan out is
to increase the number of contact pads, i.e., to decrease the
effective pitch (distance) between the contact pads.
[0154] FIG. 26 shows a further modification of the fifth embodiment
of the present invention wherein the bottom type contact pad 36 is
coupled to a connector provided on a printed circuit board or other
structure. In the example of FIG. 26, a contact pad 36 connected to
the contact structure 30 is connected to a connector 46.sub.2 via a
triple layer TAB lead 78 which has the same shape as that shown in
FIG. 24. The connector 46.sub.2 is provided on a support structure
52.sub.4.
[0155] The connector 46.sub.2 may be mechanically fixed to the
support structure 52.sub.4 through an attachment mechanism (not
shown). The end of the TAB lead 78 is inserted in a receptacle (not
shown) of the connector 46.sub.2. As is well known in the art, such
a receptacle has a spring mechanism to provide a sufficient contact
force when receiving the end of the TAB lead 78 therein. Between
the upper lead A and the intermediate lead B of the double layer
TAB lead 78, there is provided a support member 54.sub.4 to support
the leads A and B. Between the intermediate lead B and the lower
lead C of the double layer TAB lead 78, there is provided a support
member 54.sub.5 to support the leads B and C.
[0156] The structure of the TAB lead 78 having the tiered leads A,
B and C establishes a low resistance and a large current capacity
in a signal path because of the three conductive leads in parallel.
This is useful in transmitting a large current such as in a ground
line or a power line of a probe card for testing a semiconductor
device with high speed without deforming the waveforms of test
signals.
[0157] FIG. 27 shows a further modification of the fifth embodiment
of the present invention wherein the bottom type contact pad 36 is
coupled to a connector provided on a printed circuit board or other
structure. In the example of FIG. 25, a contact pad 36 provided at
the bottom surface of the contact substrate 20 is connected to a
connector 46.sub.4 via a triple layer TAB lead 78.sub.2. The triple
layer TAB 78.sub.2 has an upper lead A, an intermediate lead B and
a lower lead C each of which is separated at the end. The connector
46.sub.4 is provided on a support structure 52.sub.4.
[0158] The connector 46.sub.4 may be mechanically fixed to the
support structure 52.sub.4 through an attachment mechanism (not
shown). The ends of the leads A, B and C of the TAB lead 78.sub.2
are inserted in receptacles (not shown) of the connector 46.sub.4.
As is well known in the art, such a receptacle has a spring
mechanism to provide a sufficient contact force when receiving the
end of the TAB lead 78.sub.2 therein. A support member 54.sub.6, is
provided between the upper lead A and the intermediate lead B and a
support member 54.sub.7 is provided between the intermediate lead B
and the lower lead C of the triple TAB lead 78.sub.2.
[0159] The structure of the TAB lead 78.sub.2 having the triple
layered leads A, B and C establishes a fan out in the vertical
dimension of the TAB lead. This is useful in distributing a signal
or power to two or more paths. Another advantage of the fan out is
to increase the number of contact pads, i.e., to decrease the
effective pitch (distance) between the contact pads.
[0160] FIGS. 28 shows a further example of the fifth embodiment of
the present invention wherein the bottom type contact pad is
coupled to an interconnect pad provided on a printed circuit board
through a conductive bump. In the example of FIG. 28, a contact
structure 30, a contact trace 32, a through hole 35 and a contact
tab 33 are formed on a contact substrate 20. The contact structure
30 is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20. Typically, the contact substrate 20 is a silicon substrate
although other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible. The
contact pad 36 is connected to a PCB (print circuit board) pad 38
provided on a PCB substrate 62 through a conductive bump 56 via a
triple layer TAB lead 78.
[0161] The contact substrate 20 is mounted on the PCB substrate 62
through a support structure 52.sub.3 and an elastomer 42. The
contact substrate 20, the elastomer 42, the support structure
52.sub.3, and the PCB substrate 62 are attached with one another
by, for example, an adhesive (not shown). Between the upper lead A
and the intermediate lead B of the double layer TAB lead 78, there
is provided a support member 54.sub.4 to support the leads A and B.
Between the intermediate lead B and the lower lead C of the double
layer TAB lead 78, there is provided a support member 54.sub.5 to
support the leads B and C.
[0162] The structure of the TAB lead 78 having the tiered leads A,
B and C establishes a low resistance and a large current capacity
in a signal path because of the three conductive leads running in
parallel. This is useful in transmitting a large current such as in
a ground line or a power line in a probe card for testing a
semiconductor device with high speed without deforming the
waveforms of test signals.
[0163] By the application of the heat, the conductive bump 56 is
reflowed onto the PCB pad 38 for attachment between the TAB lead 78
and the PCB pad 38. An example of the conductive bump 56 is a
solder bump used in a standard solder ball technology. Another
example of the conductive bump 56 is a fluxless solder ball used in
a plasma-assisted dry soldering technology.
[0164] FIG. 29 shows another example of the fourth embodiment of
the present invention. In this example, a triple layered TAB lead
78.sub.2 having upper, intermediate and lower leads A, B and C is
provided to the contact pad 36 connected to the contact structure
30. The upper lead A is provided in an upper and outer position of
FIG. 29 than the intermediate lead B. The intermediate lead B is
provided in an upper and outer position than the lower lead C in
FIG. 29. The upper lead A is connected to a PCB pad 38 through a
conductive bump 56, the intermediate lead B is connected to a PCB
pad 39 through a conductive bump 57, and the lower lead C is
connected to a PCB pad 40 through a conductive bump 58. To
accommodate the PCB pads 38, 39 and 40 thereon, a PCB substrate
62.sub.4 is arranged to have steps to mount the PCB pads 38, 39 and
40 with different vertical positions. A support member 54.sub.6, is
provided between the upper lead A and the intermediate lead B and a
support member 54.sub.7 is provided between the intermediate lead B
and the lower lead C.
[0165] By the application of the heat, the conductive bumps 56, 57
and 58 are reflowed onto the PCB pads 38, 39 and 40 for attachment
between the TAB lead 78.sub.2 and the PCB pads 38, 39 and 40. An
example of the conductive bumps 56, 57 and 58 is a solder bump used
in a standard solder ball technology. Another example of the
conductive bumps 56, 57 and 58 is a fluxless solder ball used in a
plasma-assisted dry soldering technology.
[0166] The structure of the TAB lead 78.sub.2 having the triple
layered leads A, B and C establishes a fan out in the vertical
dimension of the TAB lead. This is useful in distributing a signal
or power to two or more paths. Another advantage of the fan out is
to increase the number of contact pads, i.e., to decrease the
effective pitch (distance) between the contact pads.
[0167] FIGS. 30 shows a further example of the fifth embodiment of
the present invention wherein the bottom type contact pad is
coupled to an interconnect pad provided on a printed circuit board
through a conductive polymer. In the example of FIG. 30, a contact
structure 30, a contact trace 32, a through hole and a contact pad
33 are formed on a contact substrate 20. The contact structure 30
is formed on the upper surface of the contact substrate 20 while
the contact pad 36 is formed on the bottom surface of the substrate
20. Typically, the contact substrate 20 is a silicon substrate
although other types of dielectric substrate, such as glass epoxy,
polyimide, ceramic, and alumina substrates are also feasible. The
contact pad 36 is connected to a PCB (printed circuit board) pad 38
provided on a PCB substrate 62 through a conductive polymer 66 via
a triple layer TAB lead 78.
[0168] The contact substrate 20 is mounted on the PCB substrate 62
through a support structure 52.sub.3 and an elastomer 42. The
contact substrate 20, the elastomer 42, the support structure
52.sub.3, and the PCB substrate 62 are attached with one another
by, for example, an adhesive (not shown). Between the upper lead A
and the intermediate lead B of the double layer TAB lead 78, there
is provided a support member 54.sub.4 to support the leads A and B.
Between the intermediate lead B and the lower lead C of the double
layer TAB lead 78, there is provided a support member 54.sub.5 to
support the leads B and C.
[0169] Most conductive polymers are designed to be conductive
between the mating electrodes normally in vertical of angled
directions and not conductive in the horizontal direction. An
example of the conductive polymer 66 is a conductive elastomer
which is filled with conductive wire that extends beyond the
surface of the elastomer.
[0170] Various other examples of the conductive polymer 66 are
possible such as an anisotropic conductive adhesive, anisotropic
conductive film, anisotropic conductive paste, and anisotropic
conductive particles. The anisotropic conductive adhesive is filled
with conductive particles that do not touch each other. The
conductive path is formed by pressing the adhesive between the two
electrodes at a specific location. The anisotropic conductive film
is a thin dielectric resin filled with conductive particles that do
not touch each other. The conductive path is formed by pressing the
film between the two electrodes at a specific location.
[0171] The anisotropic conductive paste is a screen printable paste
which is filled with conductive particles that do not touch each
other. The conductive path is formed by pressing the paste between
the two electrodes at a specific location. The anisotropic
conductive particle is a thin dielectric resin filled with
conductive particles coated with a very thin layer of dielectric
material to improve isolation. The conductive path is formed by
pressing the particle with enough force to explode the dielectric
coating on the particles, between the two electrodes at a specific
location.
[0172] The structure of the TAB lead 78 having the tiered leads A,
B and C establish a low resistance and a large current capacity in
a signal path because of the three conductive leads. This is useful
in transmitting a large current such as in a ground line or a power
line for testing a semiconductor device with high speed without
deforming the waveforms of test signals.
[0173] FIG. 31 shows another example of the fifth embodiment of the
present invention. In this example, a triple layered TAB lead
78.sub.2 having upper, intermediate and lower leads A, B and C is
provided to the contact pad 36 connected to the contact trace 32
and contact structure 30. The upper lead A is provided in an upper
and outer position than the intermediate lead B in FIG. 31. The
intermediate lead B is provided in an upper and outer position of
FIG. 31 than the lower lead C. The upper lead A is connected to a
PCB pad 38 through a conductive polymer 66, the intermediate lead B
is connected to a PCB pad 39 through a conductive polymer 67, and
the lower lead C is connected to a PCB pad 40 through a conductive
polymer 68. To accommodate the PCB pads 38, 39 and 40 thereon, a
PCB substrate 62.sub.4 is arranged to have steps to mount the PCB
pads 38, 39 and 40 with different vertical positions. A support
member 54.sub.6 is provided between the upper lead A and the
intermediate lead B and a support member 54.sub.7 is provided
between the intermediate lead B and the lower lead C.
[0174] The structure of the TAB lead 78.sub.2 having the triple
layered leads A, B and C establishes a fan out in the vertical
dimension of the TAB lead. This is useful in distributing a signal
or power to two or more paths. Another advantage of the fan out is
to increase the number of contact pads, i.e., to decrease the
effective pitch (distance) between the contact pads.
[0175] FIG. 32 shows a sixth embodiment of the present invention
wherein a top contact trace is coupled to a first contact target
through a single layer TAB lead while a bottom type contact pad is
coupled to a second contact target through a double layer TAB lead.
In the example of FIG. 32, the contact structure 30 formed on a
contact substrate 20 is electrically connected to the contact pad
36 via the contact trace 32 and the through hole 35. The contact
structure 30 and the contact trace 32 are formed on the upper
surface of the contact substrate 20 while the contact pad 36 is
formed on the bottom surface of the substrate 20.
[0176] The contact trace 32 is connected at its upper surface to a
single layer TAB lead 79 whose other end is connected to a printed
circuit board (PCB) pad 38 on a PCB substrate 62.sub.3 through a
conductive polymer 66. The contact pad 36 is connected at its
bottom surface with a two layer TAB lead 76.sub.4 whose other end
is connected to a PCB pad 39 on the PCB substrate 62.sub.3 through
a conductive polymer 67.
[0177] The contact substrate 20 is mounted on the PCB substrate
62.sub.3 through an elastomer 42 and a support structure 52.sub.3.
The contact substrate 20, the elastomer 42, the support structure
52.sub.3 and the PCB substrate 62 are fixed with one another by,
for example, an adhesive (not shown). In this example, the single
layer TAB lead 79 for connecting the contact trace 32 and the
contact pad 38 is supported by a support member 54.sub.8 which is
provided between the TAB leads 79 and 76.sub.4. The double layered
TAB lead 76.sub.4 for connecting the contact pad 36 and the PCB pad
39 has an upper lead A and a lower lead B. A support member
54.sub.2 is provided between the upper lead A and the lower lead B
of the double layered TAB lead 76.sub.4. In this embodiment, the
conductive polymer 66 and 67 can be replaced with conductive bumps
such as solder balls for connecting the contact structure to the
PCB pads 38 and 39. Alternatively, the TAB leads 79 and 76.sub.4
can be directly connected to the PCB pads 38 and 39.
[0178] The structure of the TAB lead 79 having the single lead and
the TAB lead 76.sub.4 having the tiered leads A and B establishes a
low resistance and a large current capacity in a signal path
because of the three conductive leads running in parallel. This is
useful in transmitting a large current such as in a ground line or
a power line in a probe card for testing a semiconductor device
with high speed without deforming the waveforms of test signals.
The structure of TAB leads in FIG. 32 also achieves flexibility in
increasing the number of contact pads.
[0179] According to the present invention, the packaging and
interconnection has a very high frequency bandwidth to meet the
test requirements in the next generation semiconductor technology.
The packaging and interconnection is able to mount the contact
structure on a probe card or equivalent thereof by electrically
connecting therewith from the bottom of the contact substrate
mounting the contact structure. Moreover, because of a relatively
small number of overall components to be assembled, the
interconnection and packaging of the present invention can be
fabricated with low cost and high reliability as well as high
productivity.
[0180] Although only a preferred embodiment is specifically
illustrated and described herein, it will be appreciated that many
modifications and variations of the present invention are possible
in light of the above teachings and within the purview of the
appended claims without departing the spirit and intended scope of
the invention.
* * * * *