U.S. patent application number 12/699683 was filed with the patent office on 2010-06-03 for apparatus for providing controlled impedance in an electrical contact.
Invention is credited to David A. Johnson, Eric V. Kline.
Application Number | 20100136840 12/699683 |
Document ID | / |
Family ID | 23517739 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100136840 |
Kind Code |
A1 |
Johnson; David A. ; et
al. |
June 3, 2010 |
APPARATUS FOR PROVIDING CONTROLLED IMPEDANCE IN AN ELECTRICAL
CONTACT
Abstract
An apparatus for providing a controlled impedance directly to
predetermined contact elements within a socket, thereby reducing
the "distorting" nature of the electrical interconnection system.
In an illustrative embodiment of the present invention,
predetermined contacts of a socket may have a resistance,
inductance, capacitance, or a combination thereof incorporated
therein. In another illustrative embodiment, at least one active
element(s) may also be incorporated into predefined contacts. In
this manner, predefined contacts may "process" the corresponding
signal in a predetermined manner, defined by the circuitry
incorporated on the contact itself. Illustrative functions that may
be performed include, but are not limited to, amplifying,
analog-to-digital converting, digital-to-analog converting,
predefined logic functions, or any other function that may be
performed via a combination of active and/or passive elements
including a microprocessor function.
Inventors: |
Johnson; David A.; (Wayzata,
MN) ; Kline; Eric V.; (Stillwater, MN) |
Correspondence
Address: |
NAWROCKI, ROONEY & SIVERTSON;SUITE 401, BROADWAY PLACE EAST
3433 BROADWAY STREET NORTHEAST
MINNEAPOLIS
MN
554133009
US
|
Family ID: |
23517739 |
Appl. No.: |
12/699683 |
Filed: |
February 3, 2010 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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12139165 |
Jun 13, 2008 |
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12699683 |
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11068136 |
Feb 28, 2005 |
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12139165 |
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10379835 |
Mar 4, 2003 |
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11068136 |
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09420830 |
Oct 19, 1999 |
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10379835 |
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08962924 |
Oct 27, 1997 |
5967848 |
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09420830 |
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08384544 |
Feb 7, 1995 |
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08962924 |
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Current U.S.
Class: |
439/630 |
Current CPC
Class: |
H01L 23/642 20130101;
H05K 1/025 20130101; H05K 7/1092 20130101; H05K 2201/10636
20130101; H01R 13/6608 20130101; H05K 2201/10689 20130101; H05K
2201/0792 20130101; H01R 13/2407 20130101; H01R 13/6473 20130101;
H05K 2201/1053 20130101; Y02P 70/50 20151101; H05K 1/023 20130101;
H05K 1/0231 20130101; H05K 2201/10515 20130101; H01L 23/64
20130101; H01R 13/2464 20130101; H05K 2201/10325 20130101; H01R
12/57 20130101; H01R 13/6464 20130101; H01R 13/6471 20130101; H01R
13/719 20130101; Y02P 70/611 20151101; H01L 2924/0002 20130101;
H01L 2924/3011 20130101; H01L 2924/0002 20130101; H01L 2924/00
20130101 |
Class at
Publication: |
439/630 |
International
Class: |
H01R 24/00 20060101
H01R024/00 |
Claims
1-39. (canceled)
40. Apparatus for electrically interconnecting leads of a packaged
semiconductor device to corresponding pads spaced at a distance
from the leads, comprising: (a) a housing, said housing having
contact receiving slots formed therein, said housing having a
surface intersected by said contact receiving slots, each of said
contact receiving slots extending substantially parallel to an axis
extending between a spaced corresponding lead and pad, said
packaged semiconductor being able to be positioned relative to said
housing proximate said contact receiving slots; (b) each lead from
said semiconductor engaging one of a plurality of contacts received
within said contact receiving slots, and each contact further
engaging a corresponding pad, wherein each pad completes a signal
path, each of said contacts providing means for electrically
affecting a signal transiting said signal path between at least one
lead and corresponding pad; and (c) each of said contacts
comprising a monolithically fabricated active device element.
41-43. (canceled)
44. Apparatus according to claim 40 wherein said plurality of
contacts is coupled to a plurality of pads.
45-48. (canceled)
49. Apparatus according to claim 40 wherein each of said contact
receiving slots registers with a corresponding lead of the
monolithically fabricated active components.
50-51. (canceled)
Description
TECHNICAL FIELD
[0001] The present invention is related to electrical interconnect
systems and more particularly relates to high performance
electrical interconnect systems which provide signal conditioning
therein.
BACKGROUND OF THE INVENTION
[0002] A plethora of applications exist for effecting electrical
contact between two conductors. Examples of such applications
include cable connectors, PC board connectors, socket connectors,
DIP carriers, etc. In an illustrative application, an interconnect
system may effect an interconnection between a number of terminals
on a first printed circuit board with a number of corresponding
terminals on a second printed circuit board. Such apparatus are
used to provide an electrical interface between two circuit boards.
In another illustrative application, an interconnect system may
effect an interconnection between a lead of an integrated circuit
device and a conductive pad or terminal on a printed circuit board.
The circuit board may then be coupled to a tester apparatus or
other control means. Such apparatus are used to evaluate the
performance of integrated circuit devices.
[0003] Numerous considerations bear upon the structure of an
electrical interconnect system, including both electrical and
mechanical considerations. For typical interconnection systems,
special attention must be given to the electrical performance
thereof including self inductance, resistance, capacitance,
impedance matching characteristics, etc. Mechanical considerations
including life span requirements, repairability or replacability,
operating temperature requirements, etc., must also be considered.
Finally, specific applications of an electrical interconnect system
may yield a number of unique parameters which must also be
considered. For example, in an interconnect system which provides
an electrical interconnection between an integrated circuit lead
and a printed circuit board terminal, various parameter must be
considered including the coplanarity of the terminals, the
mechanical manufacturing tolerances, and the device alignment and
orientation of the device terminals relative to the interconnection
system.
[0004] A main objective of an interconnection system is to maintain
a non-distorting electrical interconnection between two terminals.
To accomplish this, an interconnection system must be carefully
designed to control the lead inductance and resistance, the
lead-to-lead capacitance, the lead-to-ground capacitance, the
electrical decoupling system, and the impedance matching
characteristic of signal paths. All of these characteristics
contribute, to some degree, to the distorting nature of the
electrical interconnection system.
[0005] Various methods have been developed to help minimize the
parasitic effects of the interrconnect system. A common method is
to provide signal condition circuits adjacent the
electro-mechanical contacts of the electrical interconnection
system. The signal conditioning circuits, typically discrete
elements such as termination components are used to adjust and
control the circuit impedance. Because the requisite signal
conditioning components and electro-mechanical contacts are
physically separated, it is difficult to attain an ideal
interconnect system, thereby compromising the accuracy, precision
and reproducibility of the interconnect system.
[0006] One prior art structure is suggested in U.S. Pat. No.
4,260,762, issued on Apr. 29, 1975 to Lockhart, Jr. Lockhart
suggests a test socket for interconnecting a dual-in-line
integrated circuit package and a printed circuit board. A capacitor
is provided in the body of the socket wherein the socket material
provides the dielectric for the capacitor. The contacts of the
capacitor are in contact with the socket connectors, which are in
turn in contact with the integrated circuit package. That is,
Lockhart suggests a test socket wherein the capacitor is provided
in the socket body, rather than on the "load board" as previously
discussed.
[0007] A scheme to connect a first circuit board containing a test
socket to a coaxial probe card, and eventually to an IC tester is
suggested in U.S. Pat. No. 4,996,487, issued on Feb. 26, 1991 to
Pope. The first circuit board has an integrated circuit test socket
connected thereto and traces from the integrated circuit test
socket to plated through-holes and further to blind vias. The
coaxial probe card then engages the blind vias to provide an
electrical communication path between the IC tester and the
integrated circuit test socket.
[0008] A method for reducing noise in a telephone jack is suggested
in U.S. Pat. No. 4,695,115, issued on Sep. 22, 1987 to Talend.
Talend suggests a modular jack for telephones in which discrete
bypass capacitors are connected to the leads of the jack to filter
out noise thereon. Talend contemplates using monolithic surface
mount capacitors which extend to a ground plane in the modular jack
element.
[0009] The use of a pi-network to reduce noise in a connector is
suggested in U.S. Pat. No. 4,853,659, issued on Aug. 1, 1989 to
Kling. Kling suggests using a planer pi-network filter comprising a
pair of shunt capacitors and an inductive member in series
therebetween. Kling contemplates using the pi-network filter in
combination with cable connectors or the like.
[0010] A millimeter-wave probe for use in injecting signals with
frequencies above 50 GHz is suggests in U.S. Pat. No. 4,983,910,
issued on Jan. 8, 1991 to Majidi-Ahy et al. In Majidi-Ahy et al. an
input impedance matching section couples the energy from a low pass
filter to a pair of matched, anti-parallel, beam lead diodes. These
diodes generate odd numbered harmonics which are passed through the
diodes by an output impedance matching network.
[0011] Finally, a capacitively loaded probe which can be used for
non-contact acquisition of both analog and digital signals is
suggested in U.S. Pat. No. 5,274,336, issued on Dec. 28, 1993 to
Crook et al. In Crook et al., the probe consists of a shielded
probe tip, a probe body which is mechanically coupled to the probe
tip, and an amplifier circuit disposed within the probe body.
SUMMARY OF THE INVENTION
[0012] The present invention overcomes many of the disadvantages of
the prior art by providing a means for electrically affecting a
signal directly within the contact elements of the interconnection
system. It is contemplated that the present invention may be
applied to any type of electrical interconnect system including,
but are not limited to, cable connectors, PC board connectors, test
socket connectors, DIP carriers, etc.
[0013] In an illustrative embodiment, the electrical interconnect
system may comprise a number of contacts wherein a first portion of
each contact may be brought into electrical communication with a
corresponding first terminal. A second portion of each contact may
be in electrical communication with a corresponding second
terminal. To enhance the performance of the interconnect system,
the present invention may provide a means for electrically
affecting a signal directly within predetermined ones of the
contacts. This may be accomplished by providing a controlled
impedance therein.
[0014] A number of advantages may be achieved by providing a
controlled impedance directly within the contact element. For
example, in an integrated circuit test application, the maximum
benefit of the controlled impedance may be achieved by having the
controlled impedance located as close as possible to the integrated
circuit lead. That is, the closer that the controlled impedance is
placed to the integrated circuit lead, the greater the benefit the
controlled impedance may have on reducing the distorting nature of
the interconnect system. In the present embodiment, the controlled
impedance may be coupled directly to the contacts within a
corresponding test socket, rather than being placed on an adjacent
load board or the like.
[0015] In one embodiment of the present invention, predetermined
contacts of the socket may have a resistance, inductance,
capacitance, and/or surface acoustical wave filer therein. Further,
predetermined contacts of the socket may have a combination of the
above reference elements, thereby forming a circuit. This
additional impedance may be used for impedance matching purposes in
order to reduce reflections or other noise mechanisms on a
corresponding signal line. Further, the added impedance may be used
to provide capacitive or inductive coupling to signal or power
pins. That is, the controlled impedance may electrically affect a
corresponding signal.
[0016] In another embodiment of the present invention,
predetermined ones of the contacts of the socket may contact a
number of independent signal traces on a load board. That is, each
contact may electrically communicate with a number of independent
signals on the load board, including the particular signal trace
which corresponds to the particular semiconductor device lead.
[0017] In another embodiment of the present invention,
predetermined contacts of the socket may have at least one active
element incorporated thereon. For example, a contact may have a
transistor, diode, etc. incorporated therein. Further, a contact
may have a combination of transistors, diodes, resistors,
capacitors, inductors, surface acoustical wave filters, gates, etc.
to form a circuit therein. In this embodiment, the impedance of the
contact may be selectively controlled by another independent
signal, as described in the previous paragraph, by the logic level
of the contact itself, or other control means.
[0018] It is recognized that the inclusion of an active element
into a particular contact of a socket may have numerous
applications. For example, a contact having just a single
transistor incorporated therein may be used to control whether a
semiconductor device, the tester, or other element is driving a
corresponding signal trace. That is, the single transistor may be
turned off, thereby substantially increasing the impedance thereof,
such that the tester or other means may drive a corresponding
signal trace without overdriving a corresponding output of the
semiconductor device. Similarly, the single transistor may be
turned on, thereby reducing the impedance thereof to a low level,
allowing the semiconductor device to drive the signal trace back to
the tester or other element. This may be especially useful with
semiconductor devices that have bi-directional input/output pins.
It is recognized that this is only one application of the present
invention and that numerous other applications are
contemplated.
[0019] As stated above, a number of active elements may be
incorporated into predefined contacts of a socket to form a circuit
therein. Inductors, capacitors, and resistors may also be
incorporated therein and combined therewith. In this configuration,
predefined contacts may "process" the corresponding signal in a
predetermined manner, defined by the circuitry incorporated on the
contact itself. For example, a number of transistors may be
incorporated in a contact wherein the number of transistor may be
arranged to provide an amplifier function. That is, the signal
provided by the semiconductor device, the tester apparatus, or
other means may be amplified by the contact of the socket. Other
illustrative functions may include, but are not limited to,
analog-to-digital converters, digital-to-analog converters,
predefined logic functions, or any other function that may be
performed via a combination of active and/or passive elements
including a microprocessor function.
[0020] In another embodiment of the present invention, the
impedance may be formed between two components within a connector.
For example, two parallel and adjacent contacts may be separated by
an insulating material thereby forming a capacitance therebetween.
One of the contacts may be coupled to a power supply lead on the
semiconductor device while an adjacent contact may be coupled
directly to ground. This configuration may provide capacitance
between the power supply and ground, thereby reducing noise on the
power supply of the semiconductor device. This embodiment may also
be used to provide isolation between signal lines or signal lines
and a power supply/ground if desired. That is, a contact that is
connected to ground may be placed between two signal contacts to
reduce the amount of cross-talk therebetween. The contact may be
shaped to control the amount of inductance on a given contact. It
should be recognized that this is only an illustrative embodiment,
and that other embodiments which provide impedance between at least
two components of a connector are contemplated.
[0021] In another embodiment, the controlled impedance may be
provided on, or incorporated in, predetermined ones of the
plurality of contacts. In the simplest embodiment, a resistance
provided by the contact itself may be changed by varying the
material or the shape thereof. In a more complex embodiment, and
not deemed to be limiting, a metal substrate (MS) may be utilized
to create a controlled impedance on predetermined contacts. For
example, two or more metal plates may be mechanically joined and
electrically insulated from one another in such a way as to form
impedance controlled (i.e., transmission line, stripline, and/or
micro-strip) electro-mechanical contacts. One metal plate may serve
as the signal plane while an adjacent metal plate may serve as an
electrical ground reference. Electrical insulation can be
accomplished by a number of means including, application of
thermal-setting dielectric coatings including polyimides, epoxies,
urethanes, etc., application of thermoplastic coatings including
polyethylene, etc., or by growing native oxide by anodization or
thermal growth. These varied approaches may allow for control of
impedance through a number of adjustable parameters including the
dielectric constant of the insulating material and the plate
separation. Mechanical joining may be accomplished by a number of
means including, suspension by or between one or more elastomeric
members and/or by referencing of the individual plates or sets of
multiple plates within pre-defined mechanical constructs, such as
slots within a housing.
[0022] In another embodiment, and not deemed to be limiting, a
ceramic substrate (CS) may be utilized to create a controlled
impedance on predetermined contacts. For example, patterned metal
may be fabricated on a ceramic substrate in such a way as to yield
an impedance controlled electro-mechanical contact. In an
illustrative embodiment, a conventional thin-film multi-layer
technology may provide a 3-terminal type capacitor wherein the
first two terminals correspond to a signal I/O and the third
terminal corresponds to a ground reference. It is also contemplated
that the same impedance controlled 3-terminal type capacitor could
be fabricated by a modified multi-layer thin-film process wherein
the conductive phase is deposited on an inert/carrier substrate and
patterned for selective oxidation using chemical anodization,
plasma oxidation and/or thermal oxide growth, yielding conductive
metal patterns within a dielectric. Finally, it is contemplated
that the process could be repeated N-times to yield a multi-layer
active contact structure of the 3-terminal type capacitor.
[0023] While the last two embodiments primarily provide an
illustrative three terminal capacitor type device, it is envisioned
that other conventional processes may be used to provide
resistance, inductance, capacitance, and/or a combination thereof
to predetermined contacts. It is further envisioned that
conventional or other processes may be used to provide other active
elements including, transistors, diodes, etc., and/or a combination
thereof to predetermined contacts. Finally, it is envisioned that
conventional or other processes may be used to provide a number of
active and/or passive elements in a circuit configuration which may
provide predefined functions, including a microprocessor function
to predetermined contacts. In the above referenced embodiments, the
electrical affecting means may be integrated with the contact
itself.
[0024] Finally, the connector apparatus comprising the above
referenced contacts may be designed such that each of the contacts
may be interchanged with another contact. This may allow a contact
having a inductor to be interchanged with another contact having a
resistor. As can readily be seen, this may allow the connector
apparatus to be configurable, even after the connector apparatus
has been assembled and is in use. That is, the connector apparatus
may be customized for a particular use, and even changed to
accommodate a new use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Other objects of the present invention and many of the
attendant advantages of the present invention will be readily
appreciated as the same becomes better understood by reference to
the following detailed description when considered in connection
with the accompanying drawings, in which like reference numerals
designate like parts throughout the figures thereof and
wherein:
[0026] FIG. 1 is a schematic side view of an active contact coupled
to a packaged semiconductor device and an interface board;
[0027] FIG. 2 is a schematic side view of an illustrative
embodiment of the active contact whereby the active contact
provides a capacitance between a packaged semiconductor device lead
and a ground plane;
[0028] FIG. 3 is a schematic side view of an illustrative
embodiment of the active contact whereby the active contact
provides a diode means to the connection between a packaged
semiconductor device and a terminal on an interface board;
[0029] FIG. 4 is a schematic side view of an illustrative
embodiment of the active contact whereby the active contact
provides a switch means to the connection between a packaged
semiconductor device and a terminal on an interface board;
[0030] FIG. 5 is a top view of an illustrative embodiment of the
active contacts whereby the active contacts are separated by a thin
non-conducting layer to provide impedance therebetween;
[0031] FIG. 6 is a perspective view of the embodiment shown in FIG.
5;
[0032] FIG. 7 is a partial fragmented perspective view of an
illustrative embodiment of the present invention including a
packaged semiconductor device and an interface board;
[0033] FIG. 8 is a perspective view of another embodiment of the
present invention having native Grown Oxide on a Metal Substrate
contact to form a controlled impedance therebetween;
[0034] FIG. 9 is a perspective view of a Metal Dielectric Sandwich
embodiment having a Metal Substrate Contact;
[0035] FIG. 10 is a perspective view of a two terminal embodiment
having a Ceramic Substrate Contact; and
[0036] FIG. 11 is a perspective view of a three terminal embodiment
having a Ceramic Substrate Contact.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] FIG. 1 is a schematic side view of an active contact coupled
to a packaged semiconductor device and an interface board 26. An
illustrative embodiment of the present invention may provide a
controlled impedance directly to predetermined contact elements
within a test socket, thereby reducing the "distorting" nature of
the electrical interconnection system. It is further contemplated
that the present invention may not be limited to test sockets, but
rather may be applied to cable connectors, PC board connectors,
test socket connectors, DIP carriers, etc.
[0038] A semiconductor device socket may comprise a number of
contacts wherein a first portion of each contact may be brought
into electrical communication with a corresponding lead of a
semiconductor device. Another portion of each contact may be in
electrical communication with a load board terminal or equivalent
and subsequently with a tester of other test means. That is, each
contact may provide a mechanical and an electrical connection
between a load board terminal and a corresponding lead on a
semiconductor device. To enhance the performance of the socket, the
present invention may electrically affect a signal by provide a
controlled impedance within predetermined ones of the contacts. The
electrical affecting means may be integrated with the corresponding
contact.
[0039] To obtain the maximum benefit of the controlled impedance
which is added to an interconnect system, it is important to have
the controlled impedance located as close as possible to the
semiconductor device lead. That is, the closer that the controlled
impedance is placed to the semiconductor device lead, the greater
the benefits the controlled impedance may have on reducing the
distorting nature of the interconnect system. In the present
embodiment, the controlled impedance may be coupled directly to the
contacts within the socket.
[0040] In the illustrative embodiment shown in FIG. 1, an active
contact 10 may be coupled to a lead 14 of a packaged semiconductor
12 via interface 18. Further, active contact 10 may be coupled to
at a load board terminal 16 via interface 20. Active contact 10 may
also be coupled to at least one other load board terminal 22 via
interface 24. Active contact 10 may provide both a mechanical and
an electrical connection between packaged semiconductor lead 14 and
load board terminals 16 and 22.
[0041] In accordance with the illustrative embodiment of the
present invention, predetermined contacts 10 of the socket may have
a resistance, inductance, capacitance, surface acoustical wave
filters, or a combination thereof incorporated therein. A
combination of resistance, inductance, capacitance, or surface
acoustical wave filters may form a circuit therein. This additional
impedance may be used for impedance matching purposes in order to
reduce reflections or other noise mechanisms on a corresponding
signal line. Further, the added impedance may be used to provide
capacitive or inductive coupling to signal or power pins.
[0042] It is contemplated that predetermined ones of the active
contacts 10 of the test socket may contact a number of signal
traces on the load board. That is, each contact 10 may electrically
communicate with, and may be mechanically engaged with, a number of
signals traces on the load board, including the particular signal
trace which corresponds to the particular semiconductor device lead
14. For example, in the embodiment shown in FIG. 1, active contact
10 may be coupled to a first load board terminal 16 and a second
load board terminal 22. It is contemplated that active contact 10
may be coupled to a plurality of load board terminals in a similar
manner.
[0043] It is further contemplated that predetermined contacts 10 of
the socket may have at least one active element incorporated
thereon or therein. For example, active contact 10 may have a
transistor, diode, etc., or a combination thereof incorporated
therein, thereby forming a circuit. It is further contemplated that
a combination of resistance, capacitance, inductance, transistors,
diodes, surface acoustical wave filters, gates, etc. may be
incorporated therein to form a circuit. In this embodiment, the
impedance of the contact may be selectively controlled by another
independent signal, as described in the previous paragraph, by the
logic level of the contact itself, or other control means. In this
embodiment, the active contact may have three ports 18, 20, and 24
as shown in FIG. 1.
[0044] FIG. 2 is a schematic side view of an illustrative
embodiment of an active contact 10A whereby the active contact 10A
provides a capacitance to an interconnection 28 extending between
the packaged semiconductor device lead 14 and load board terminal
16. In the illustrative embodiment, a capacitor 30 may have a first
lead coupled to the interconnection 28 between the packaged
semiconductor device lead 14 and load board terminal 16. The
capacitor 30 may have a second lead coupled to load board terminal
22 via interface 24. In this configuration, load board terminal 22
may be grounded, thereby providing a capacitance between the
interconnection 28 and ground. FIG. 2 is only illustrative, and it
is contemplated that active contact 10A may comprise an inductor,
resistor, diode, surface acoustical wave filter, or any other
element which provides impedance and/or control thereto. It is
further contemplated that active contact 10A may comprise any
combination of the above reference elements thereby forming a
circuit.
[0045] FIGS. 3-4 show illustrative embodiments having active
elements disposed on active contact 10. FIG. 3 shows a schematic
side view of an illustrative embodiment of the active contact
whereby an active contact 10C provides a diode means 36 between the
packaged semiconductor device lead 14 and load board terminal 16.
This configuration allows the semiconductor device 12 to supply
current to load board terminal 16 but does not allow current to
flow from load board terminal 16 into the semiconductor device 12.
Similarly, FIG. 4 shows a schematic side view of an illustrative
embodiment of the active contact whereby an active contact 10D
provides a switch means between packaged semiconductor device lead
14 and lead board terminal 16. In the illustrative embodiment, the
switch means may comprise a transistor 40 having a gate, source,
and drain. The drain of the transistor 40 may be coupled to the
semiconductor device lead 14 via interface 18, the source of the
transistor 40 may be coupled to load board terminal 16 via
interface 20, and the gate of the transistor 40 may be coupled to
load board terminal 22 via interface 24. In this configuration,
load board terminal 22 may control the impedance between load board
terminal 16 and semiconductor device lead 14. Further, active
contact 10D may have three ports 18, 20, and 24.
[0046] It is recognized that the inclusion of an active element
into predetermined contacts 10 of a socket may have numerous
applications. For example, a contact having a single transistor
incorporated therein, as shown in FIG. 4, may be used to control
whether the semiconductor device or the tester is driving a
corresponding load board terminal. That is, the single transistor
40 may be turned off by applying an appropriate voltage to load
board terminal 22, thereby substantially increasing the impedance
of the path from the semiconductor device lead 14 to load board
terminal 16, such that the tester may drive a corresponding load
board terminal 16 without overdriving an output of the
semiconductor device 12. Similarly, the single transistor 40 may be
turned on by applying an appropriate voltage to load board terminal
22, thereby reducing the impedance of the path from the
semiconductor device lead 14 to load board terminal 16, allowing
the semiconductor device 12 to drive load board terminal 16 back to
the tester, or visa-versa. This may be especially useful with
semiconductor devices that have bi-directional input/output pins.
It is recognized that this is only one application of the present
invention and that numerous other applications are
contemplated.
[0047] As stated above, it is further contemplated that a number of
active elements may be incorporated into predefined contacts 10 of
a socket to form a circuit therein. Inductors, capacitors,
resistors, and/or surface acoustical wave filters may also be
incorporated therein and combined therewith. In this embodiment,
predefined contacts may "process" the corresponding signal in a
predetermined manner, defined by the circuitry incorporated on
active contact 10 itself. For example, a number of transistors may
be incorporated in active contact 10 wherein the number of
transistor may be arranged to provide an amplifier function. That
is, the signal provided by the semiconductor device 40 or tester
apparatus (not shown) may be amplified by active contact 10 of the
socket. Other illustrative functions may include, but are not
limited to, analog-to-digital conversion, digital-to-analog
conversion, predefined logic functions, or any other function that
may be performed via a combination of active and/or passive
elements, including a microprocessor function.
[0048] FIG. 5 is a top view of an illustrative embodiment of the
active contacts whereby the active contacts are separated by a thin
insulating material to provide impedance therebetween. FIG. 6 is a
perspective view of the embodiment shown in FIG. 5.
[0049] In an illustrative embodiment, a number of "S" shaped
contacts may be provided wherein each "S" shaped contact may engage
a corresponding lead of a semiconductor device 138. A first hook
portion 141 of each "S" shaped contact may engage a first elastomer
element 142. A second hook portion 143 of each "S" shaped contact
may engage a second element 144. The second element 144 may be
constructed from a solid material or an elastomeric material. As a
lead 137 of a semiconductor device 138 engages a corresponding "S"
shaped contact 135, elastomer element 142 may deform thereby
permitting "S" shaped contact 135 to deflect away from the
corresponding semiconductor device lead 137. This may help
compensate for non-planer device leads on a corresponding
semiconductor device 138.
[0050] Referring to FIGS. 5 and 6, the impedance may be formed
between two components within the socket. For example, two parallel
and adjacent contacts 134 and 135 may be separated by an insulating
material 136 thereby forming a capacitance therebetween. One of the
contacts 135 may be engaged by a power supply pin 137 on a
corresponding semiconductor device 138 while an adjacent contact
134 may be engaged by a ground pin 139. This configuration provides
capacitance between the power supply and ground, thereby reducing
noise on the power supply of the semiconductor device 138.
[0051] The present embodiment may also be used to provide isolation
between signal lines or signal lines and a power supply/ground if
desired. That is, a contact 137 may be connected to ground and may
be placed between two signal contacts 134 and 140 to reduce the
amount of cross-talk therebetween. The contact may be shaped to
control the amount of inductance on a given contact.
[0052] In one embodiment, a first contact 135, an insulating
material 136, and a second contact 134 may be sandwiched together
to form an impedance therebetween. This may be accomplished by
using a conventional lamination process. In another embodiment, the
first contact 135 and/or the second contact 134 may have an oxide
coating placed thereon. The oxide coating may be grown on the outer
surface of the contacts using a standard oxidation processes. In
this configuration, the first contact 135 may be brought into
direct contact with the second contact 134 while maintaining
electrical isolation therebetween.
[0053] It is recognized that the above referenced embodiments are
only illustrative, and that other embodiments which provide
impedance between at least two components of a socket are
contemplated.
[0054] FIG. 7 is a partial fragmented perspective view of an
illustrative embodiment of the present invention including a
packaged semiconductor device and an interface board. As stated
above, the controlled impedance may be provided on, or incorporated
in, predetermined ones of the plurality of contacts.
[0055] In the simplest embodiment, the resistance provided by the
contact may be changed by varying the material or the shape
thereof. In a more complex embodiment, and not deemed to be
limiting, a metal substrate (MS) may be utilized to create a
controlled impedance on predetermined ones of the plurality of
contacts. For example, two or more metal planes may be mechanically
joined and electrically insulated from one another in such a way as
to form impedance controlled (i.e., stripline) electro-mechanical
contacts. One metal plane may serve as the signal plane while an
adjacent metal plane may serve as an electrical ground reference.
Electrical insulation can be accomplished by a number of means,
including, application of thermal-setting dielectric coatings
including polyimides, epoxies, urethanes, etc., application of
thermoplastic coatings including polyethylene, etc., or by growing
native oxide by anodization or thermal growth. These varied
approaches may allow for control of impedance through the
adjustable parameters of the dielectric constant of the insulating
material and the plane separation. Mechanical joining may be
accomplished by a number of means, including, suspension by or
between one or more elastomeric members and/or by referencing of
the individual planes or sets of multiple planes within pre-defined
mechanical constructs such as slots within a housing.
[0056] Essentially any metal may be used for this embodiment of the
active contact. Aluminum is a preferred material since it is
readily anodizable, and yields a good quality and
well-characterized dielectric film. Other metals that may be used
include, but are not limited to, copper and copper alloys, steels
and Ni--Fe alloys, NiCr alloys, transition metals and alloys, and
intermetallics. Some of these non-traditional contact metals may be
useful either in a plated or non-plated embodiment to adjust and
control the contact's bulk resistance.
[0057] Referring specifically to FIG. 7, a packaged semiconductor
device 112 having at least one lead 114 may be received in a
housing 116, such that the at least one lead 114 may be in
electro-mechanical contact with an active contact 130.
Semiconductor device 112 may be positioned in place by a lead
channel 118 or other orienting means.
[0058] Active contact 130 may comprise a device element 120 and a
plate 126. The device element 120 and the plate 126 may be
constructed from a metallic material, as discussed above. The at
least one lead 114 of semiconductor device 112 may be in
electro-mechanical contact with a first portion of device element
120. Similarly, a second portion of device element 120 may be in
electro-mechanical contact with a signal I/O pad 128 on a load
board 122, thus completing a signal path from semiconductor device
112 to load board 122. Signal I/O pad 128 may be coupled to a
tester or another element.
[0059] Device element 120 may be mechanically bonded to plate 126
via a dielectric material 124 such that the two conducting
surfaces, comprising device element 120 and plate 126, may be
orientated parallel to one another and separated by a distance
substantially equal to the thickness of dielectric material 124.
Plate 126 may be electro-mechanically connected to a ground pad 132
on load board 122, such that the construct yields a transmission
line structure such as a micro-strip type impedance controlled
active contact. It is recognized that ground pad 132 may be coupled
to a fixed voltage or to a tester. When connected to a tester, the
voltage on ground pad 132 may be varied to provide a time varying
impedance signature to the corresponding signal path.
[0060] In another embodiment utilizing a metal substrate as
discussed above, a precise thickness of metal oxide may be grown on
the surface of device element 130 and/or plate 126. The native
grown metal oxide may function as the dielectric between device
element 130 and plate 126. It is contemplated that the native grown
metal oxide may comprise an inorganic oxide dielectric coating.
[0061] Another embodiment which utilizes the native grown metal
oxide configuration is shown in FIG. 8. The active contact is
generally shown at 150 and may comprise a first contact element 152
and a second contact element 154. A metal oxide may be selectively
grown on contact elements 152 and/or 154 such that no metal oxide
is present on contacting surfaces 158A, 158B, or 158C. It is also
contemplated that the metal oxide may be grown over the entire
outer surface of contacting elements 152 and/or 154, and then
selectively removed from contacting surfaces 158A, 158B, and 158C.
Contacting surface 158A may be in electro-mechanical contact with a
lead of a semiconductor device (not shown). Similarly, contacting
point 159B may be in electro-mechanical contact with a signal I/O
pad on a load board (not shown). Finally, contacting surface 158C
may be in electro-mechanical contact with a ground pad on the load
board (not shown).
[0062] In this configuration, first contact element 152 may be
placed in contact with second contact element 154, while
maintaining electrical isolation therebetween. Various metal plane
configurations which allow adjustment and control of the electrical
and mechanical interface characteristics are contemplated,
including the shape of the contacting elements 152 and 154, the
oxide thickness grown thereon, the mutual surface areas, the plane
separation distance, and other parameters.
[0063] Finally, it is contemplate that a window 160, or multiple
windows, may be incorporated into the design of the contacting
elements 152 and 154. Window 160 may be employed as a conduit for a
mechanically elastomeric member which may support the active
contact 150. The elastomer member (not shown) may be used to
provide an upward biasing of contact surface 158A such that as a
semiconductor lead is brought into engagement therewith, the
elastomer member may deform thereby permitting active contact 150
to deflect away from the semiconductor device lead. This may help
compensate for non-planer device leads on a corresponding
semiconductor device.
[0064] Another illustrative embodiment that may use the metal
substrate concept discussed above is shown in FIG. 9. In this
embodiment, a known precise thickness of thermal setting or
thermoplastic dielectric 124 may be laminated between two or more
metal plates 120 and 126 in order to achieve the desired
electro-mechanical characteristics. It is contemplated that the two
or more metal plates may comprise two or more isolated circuits.
That is, each of the two or more metal plates may comprise a
circuit function. It is further contemplated that a dielectric 124
may be constructed from polyimide, epoxy, polycarbonate,
polyphenylene sulfide, or any other suitable material. An etch-back
of the dielectric 124 may be incorporated into the fabrication
process to facilitate ohmic contact on contacting surfaces 158D,
158E, and 158F.
[0065] In another embodiment of the present invention, a ceramic
substrate may be utilized to create a controlled impedance on
predetermined ones of a plurality of contacts. For example,
patterned metal may be fabricated on a ceramic substrate in such a
way as to yield an impedance controlled electro-mechanical contact.
In an illustrative embodiment, a conventional thin-film multi-layer
technology may provide a 3-terminal type capacitor wherein the
first two terminals may correspond to a signal I/O and the third
terminal may be in contact with a ground reference. It is also
contemplated that the same impedance controlled 3-terminal type
capacitor could be fabricated by a modified multi-layer thin-film
process wherein the conductive phase is deposited on an
inert/carrier substrate and patterned for selective oxidation using
chemical anodization, plasma oxidation and/or thermal oxide growth,
yielding conductive metal patterns within a dielectric. Finally, it
is contemplated that the process may be repeated N-times to yield a
multi-layer active contact structure of the 3-terminal type
capacitor.
[0066] While the last two embodiments primarily provide an
illustrative three terminal capacitor type device, it is envisioned
that other conventional processes may be used to provide
resistance, inductance, capacitance, surface acoustical wave
filter, and/or a combination thereof to predetermined contacts. It
is further envisioned that conventional or other processes may be
used to provide other active elements including, transistors,
diodes, etc., and/or a combination thereof to predetermined
contacts. Finally, it is envisioned that conventional or other
processes may be used to provide a number of active and/or passive
elements to provide a circuit which may provide predefined
functions, including a microprocessor function to predetermined
contacts. That is, in an alternative embodiment, predetermined ones
of the above referenced multi-layers each may comprise an isolated
circuit.
[0067] In an illustrative embodiment, as shown in FIG. 10, a
ceramic substrate 202 having a first contacting surface 158G and a
second contacting surface 158H may be provided. A metal film may be
deposited directly on the ceramic substrate. Subsequently, the
metal film may be patterned via an etch or other subtractive
process to form a first conducting surface 204 and a second
conducting surface 206. The metal film may cover the first
contacting surface 158G and the second contacting surface 158H to
provide a conductive surface thereto. In the illustrative
embodiment, there may be a gap between the first conductive surface
204 and the second conductive surface 206 such that there is no
electrical connection therebetween. A discrete and/or
monolithically fabricated active components may be affixed such
that a first electrical terminal 210 of the discrete and/or
monolithically fabricated active component is in electrical
communication with the first conductive surface 204 and a second
electrical terminal 212 of the discrete and/or monolithically
fabricated active component 208 is in electrical communication with
the second conductive surface 206. It is contemplated that the
discrete and/or monolithically fabricated active component may be a
resistor, capacitor, inductor, diode, or any combination thereof.
Further, it is contemplated that the shape of the ceramic substrate
and the pattern of the metal film may be such that a transistor or
other multi-terminal device may be employed. Finally, it is
contemplated that a number of resistor, capacitor, inductor, diode,
transistors, etc. may be employed to create a circuit thereon.
[0068] In the illustrative embodiment, the employment of low
conductivity metals or even conductive inks and ceramics, including
SiC, may be used to achieve the desired resistance values, with or
without additive plating such as gold to minimize contact
resistance. However, it is contemplate that an additive plating may
be used. The ohmic contacting surfaces 158G and 158H of active
contact 200 may be in electro-mechanical contact with a
semiconductor lead and a load board terminal, respectively. The
first conductive surface 204 may carry an electrical signal from
the semiconductor lead to the first electrical terminal 210 of the
discrete or integrated component 208. The signal may emerge at the
second electrical terminal 212 of the discrete or integrated
component 208 and may be carried by the second conductive surface
206 to the ohmic contacting surface 158H, and finally to a load
board's signal I/O pad (not shown). In the embodiment shown in FIG.
10, a recess may be fabricated in the ceramic subtract to
accommodate the physical placement of the discrete and/or
monolithically fabricated active component 208.
[0069] Referring to FIG. 11, another illustrative embodiment which
uses the ceramic substrate, may comprise a 3-terminal capacitor
type active contact. In this embodiment, the contact may comprise a
multi-layer monolithic decoupling capacitor. Alternating signal
planes 258 and ground planes 266 may be fabricated from patterned
metal and separated by inter-layer ceramic dielectric (not shown).
This may be accomplished by repeating a multi-layer thin film
process N-times to yield a multi-layer active contact structure as
shown in FIG. 11.
[0070] The network of signal planes 258 may be coupled to a first
terminal 254 by a via 256, and to a second terminal 260 by a via
268. The first terminal 254 may be brought into engagement with a
lead of a semiconductor device. The second terminal 260 may be in
contact with a signal I/O pad 128 on a load board (not shown). The
ground network 266 may be electrically coupled to a ground
reference ohmic contact 262 by a via 264. The ground reference
ohmic contact 262 may be coupled to a ground reference pad 132 on a
load board (not shown). This embodiment may provide a significant
amount of control over a corresponding signal because of the
relatively large plate area generated by the alternating
configuration of the signal and ground planes.
[0071] Having thus described the preferred embodiments of the
present invention, those of skill in the art will readily
appreciate that the teachings found herein may be applied to yet
other embodiments within the scope of the claims hereto
attached.
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