U.S. patent application number 11/958889 was filed with the patent office on 2008-04-24 for semiconductor component and method of manufacture.
This patent application is currently assigned to HVVI SEMICONDUCTORS, INC.. Invention is credited to Jeanne S. Pavio.
Application Number | 20080093718 11/958889 |
Document ID | / |
Family ID | 40752111 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080093718 |
Kind Code |
A1 |
Pavio; Jeanne S. |
April 24, 2008 |
SEMICONDUCTOR COMPONENT AND METHOD OF MANUFACTURE
Abstract
A semiconductor component having a semiconductor chip mounted on
a packaging substrate and a method for manufacturing the
semiconductor component that uses batch processing steps for
fabricating the packaging substrate. A heatsink is formed using an
injection molding process. The heatsink has a front surface for
mating with a semiconductor chip and a leadframe assembly. The
heatsink also has a back surface from which a plurality of fins
extend. The leadframe assembly includes a leadframe having
leadframe leads extending from opposing sides of the leadframe to a
central area of the leadframe. A liquid crystal polymer is disposed
in a ring-shaped pattern on the leadframe leads. The liquid crystal
polymer is partially cured. The leadframe assembly is mounted on
the front surface of the heatsink and the liquid crystal polymer is
further cured to form a packaging assembly, which is then
singulated into packaging substrates.
Inventors: |
Pavio; Jeanne S.; (Paradise
Valley, AZ) |
Correspondence
Address: |
HVVI SEMICONDUCTORS, INC.
c/o PORTFOLIOIP
P.O. BOX 52050
MINNEAPOLIS
MN
55402
US
|
Assignee: |
HVVI SEMICONDUCTORS, INC.
10235 South 51st Street Suite 100
Phoenix
AZ
85044
|
Family ID: |
40752111 |
Appl. No.: |
11/958889 |
Filed: |
December 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11327552 |
Jan 6, 2006 |
7335534 |
|
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11958889 |
Dec 18, 2007 |
|
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60642680 |
Jan 10, 2005 |
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Current U.S.
Class: |
257/675 ;
257/E21.505; 257/E21.51; 257/E21.511; 257/E23.051; 257/E23.069;
257/E23.104; 257/E23.107; 257/E23.185; 438/111; 438/122 |
Current CPC
Class: |
H01L 2924/15311
20130101; H01L 2224/83801 20130101; H01L 2924/00014 20130101; H01L
2924/01033 20130101; H01L 23/3737 20130101; H01L 24/97 20130101;
H01L 2924/00014 20130101; H01L 2924/15787 20130101; H01L 2924/15747
20130101; H01L 2224/16 20130101; H01L 24/29 20130101; H01L
2224/83192 20130101; H01L 23/047 20130101; H01L 2224/05666
20130101; H01L 23/66 20130101; H01L 2224/05644 20130101; H01L
2224/05639 20130101; H01L 2924/12044 20130101; H01L 2224/05666
20130101; H01L 2224/05573 20130101; H01L 24/81 20130101; H01L
2924/0665 20130101; H01L 23/49816 20130101; H01L 2924/16152
20130101; H01L 2924/16152 20130101; Y10T 29/49121 20150115; H01L
2224/05644 20130101; H01L 2924/00014 20130101; H01L 2224/81801
20130101; H01L 2224/97 20130101; H01L 2224/05639 20130101; H01L
2924/01029 20130101; H01L 2924/3011 20130101; H01L 2924/15787
20130101; H01L 2924/014 20130101; H01L 2224/05599 20130101; H01L
2224/0555 20130101; H01L 2224/05655 20130101; H01L 2924/00
20130101; H01L 2924/01013 20130101; H01L 2224/05568 20130101; H01L
2924/00 20130101; H01L 2224/0556 20130101; H01L 2924/00014
20130101; H01L 2224/73253 20130101; H01L 2224/73253 20130101; H01L
2924/00014 20130101; H01L 2924/00 20130101; H01L 2924/00014
20130101; H01L 2924/15311 20130101; H01L 2924/00014 20130101; H01L
2924/0665 20130101; H01L 2924/00 20130101; H01L 2224/97 20130101;
H01L 2224/0554 20130101; H01L 2924/01006 20130101; H01L 2924/01082
20130101; H01L 2924/01047 20130101; H01L 2224/05655 20130101; H01L
2924/15747 20130101; H01L 2924/01078 20130101; H01L 2924/0665
20130101; H01L 2224/73253 20130101; H01L 2224/2919 20130101; H01L
2924/166 20130101; H01L 2924/0105 20130101; H01L 2924/14 20130101;
H01L 2224/2919 20130101; H01L 24/83 20130101; H01L 2224/97
20130101; H01L 2924/00014 20130101; H01L 2924/01074 20130101; H01L
23/3675 20130101; H01L 2924/01079 20130101 |
Class at
Publication: |
257/675 ;
438/122; 438/111; 257/E21.505; 257/E23.051 |
International
Class: |
H01L 23/495 20060101
H01L023/495; H01L 21/58 20060101 H01L021/58 |
Claims
1. A method for manufacturing a semiconductor component, comprising
the steps of: providing a heatsink having first and second major
surfaces; providing a leadframe having at least one leadframe lead;
disposing a liquid crystal polymer on a portion of the at least one
leadframe lead; partially curing the liquid crystal polymer; and
mating the liquid crystal polymer and the heatsink.
2. The method of claim 1, wherein the step of providing the
heatsink includes providing the heatsink with a platform that
serves as a die receiving area.
3. The method of claim 2, wherein the step of providing the
heatsink includes contemporaneously forming the heatsink and the
platform using an injection molding process.
4. The method of claim 1, wherein providing the heatsink includes
forming at least one fin extending from the second major surface of
the heatsink.
5. The method of claim 4, wherein the step of forming the at least
one fin includes forming the at least one fin to have a
quadrilateral shape.
6. The method of claim 5, wherein forming the at least one fin
comprises forming at least three fins, wherein each of the at least
three fins has a quadrilateral shape and are substantially parallel
to each other.
7. The method of claim 6, wherein forming the at least one fin
includes forming the at least one fin to have a pyramidal
shape.
8. The method of claim 1, further including the step of further
curing the liquid crystal polymer after mating the liquid crystal
polymer and the heatsink.
9. The method of claim 8, wherein the step of disposing the liquid
crystal polymer on the portion of the at least one leadframe lead
includes dispensing the liquid crystal polymer on the at least one
portion of the leadframe lead.
10. The method of claim 8, wherein the step of further curing the
liquid crystal polymer includes fully curing the liquid crystal
polymer.
11. The method of claim 8, wherein the step of providing the
heatsink includes forming the heatsink using an injection molding
process.
12. The method of claim 8, wherein the step of providing a
leadframe having at least one leadframe lead includes providing a
leadframe having first and second opposing sides spaced apart from
each other by a central area, wherein a first leadframe lead
extends from the first side into the central area and a second
leadframe lead extends from the second side into the central
area.
13. The method of claim 12, wherein the step of disposing the
liquid crystal polymer includes disposing the liquid crystal
polymer in a ring-shaped pattern having first and second opposing
sides and third and fourth opposing sides, and wherein the first
side of the ring-shaped pattern is disposed on the first leadframe
lead and the second side of the ring-shaped pattern is disposed on
the second leadframe lead.
14. The method of claim 13, wherein the first side of the
ring-shaped pattern is disposed on a central portion of the first
leadframe lead and the second side of the ring-shaped pattern is
disposed adjacent an end of the ring-shaped pattern.
15. The method of claim 8, wherein the step of providing a
leadframe having at least one leadframe lead includes providing a
leadframe having first and second opposing sides spaced apart from
each other by a central area, wherein a plurality of leadframe
leads extends from the first side into the central area and a
plurality of lead extends from the second side into the central
area.
16. The method of claim 15, wherein the step of disposing the
liquid crystal polymer includes disposing the liquid crystal
polymer in a ring-shaped pattern having first and second opposing
sides and third and fourth opposing sides, and wherein the first
side of the ring-shaped pattern is disposed on the plurality of
leadframe leads extending from the first side of the leadframe and
the second side of the ring-shaped pattern is disposed on the
plurality of leadframe leads extending from the second side of the
leadframe.
17. The method of claim 16, wherein the step of providing a
leadframe having at least one leadframe lead includes providing the
leadframe having third and fourth opposing sides spaced apart from
each other by the central area, wherein a plurality of leadframe
leads extends from the third side into the central area and a
plurality of leadframe leads extends from the fourth side into the
central area, and wherein the step of disposing the liquid crystal
polymer includes disposing the third side of the ring-shaped
pattern on the plurality of leadframe leads extending from the
third side and disposing the fourth side of the ring-shaped pattern
on the plurality of leadframe leads extending from the fourth
side.
18. The method of claim 8, further including the steps of:
providing a semiconductor chip having first and second major
surfaces, wherein a gate structure is formed over the first major
surface; and coupling the first major surface of the semiconductor
chip with the first major surface of the heatsink.
19. The method of claim 18, wherein the step of providing the
semiconductor chip includes forming a metallization system on the
first major surface of the semiconductor chip and wherein the step
of coupling the first major surface of the semiconductor chip with
the first major surface of the heatsink comprises soldering the
semiconductor chip to the first major surface of the heatsink.
20. The method of claim 19, wherein the metallization system
comprises one of a tin-nickel-gold metallization system or a
tin-nickel-silver metallization system.
21. The method of claim 18, further including coupling a metal clip
to the second side of the semiconductor chip and to a first
leadframe lead of the plurality of leadframe leads.
22. The method of claim 21, further including the step of placing a
lid over the semiconductor chip, wherein a portion of the lid is
coupled to the metal clip.
23. The method of claim 21, wherein the step of providing the
semiconductor chip includes forming a metallization system on the
second major surface of the semiconductor chip and soldering the
metal clip to the metallization system on the second major surface
of the semiconductor chip.
24. The method of claim 23, wherein the metallization system on the
second major surface of the semiconductor chip comprises aluminum
with a nickel-gold alloy disposed thereon.
25. The method of claim 18, further including electrically coupling
the gate structure to a second leadframe lead of the plurality of
leadframe leads.
26. The method of claim 25, further including the step of soldering
the lid to the semiconductor chip.
27. The method of claim 8, further including the step of coupling
at least one other semiconductor chip to the heatsink.
28. The method of claim 27, wherein the step of coupling the at
least one other semiconductor chip to the heatsink includes
coupling a switching chip to the heatsink and coupling a mixed
signal integrated circuit to the heatsink.
29. A method for manufacturing a semiconductor component,
comprising the steps of: forming a plurality of heatsinks, each
heatsink of the plurality of heatsinks having first and second
major surfaces; providing a leadframe having a plurality of
leadframe leads; disposing a liquid crystal polymer on the
plurality of leadframe leads; partially curing the liquid crystal
polymer; coupling the leadframe to the plurality of heatsinks
through the partially cured liquid crystal polymer to form a
packaging frame comprising a plurality of packaging substrates; and
singulating the packaging frame to separate the plurality of
packaging substrates from each other.
30. The method of claim 29, wherein the step of forming the
heatsink comprises using an injection molding process.
31. The method of claim 30, wherein the step of forming the
heatsink comprises forming the heatsink having a quadrilateral
shape.
32. The method of claim 30, wherein the step of disposing the
liquid crystal polymer on the plurality of leadframe leads
comprises disposing the liquid crystal polymer in a quadrilateral
ring-shaped pattern.
33. The method of claim 29, further including the step of further
curing the liquid crystal polymer.
34. The method of claim 33, further including coupling a
semiconductor chip to the heatsink, electrically coupling the
semiconductor chip to at least one leadframe lead of the plurality
of leadframe leads, and disposing a glob top material over the
semiconductor chip.
35. A method for manufacturing a semiconductor component,
comprising the steps of: providing a heatsink having first and
second major surfaces; providing a ball grid array substrate having
a first major surface and a second major surface, the second major
surface having solder balls coupled thereto; disposing a liquid
crystal polymer on a portion of the first major surface of the ball
grid array substrate; partially curing the liquid crystal polymer;
mating a first major surface of a semiconductor chip to the liquid
crystal polymer; and mating a second major surface of the
semiconductor chip to the heatsink.
36. The method of claim 35, wherein providing the heatsink includes
providing fins extending from the second major surface of the
heatsink.
37. The method of claim 36, wherein partially curing the liquid
crystal polymer includes partially curing the liquid crystal
polymer at a temperature ranging from about 260.degree. C. to about
280.degree. C. for a time ranging from about 20 minutes to about 60
minutes.
38. The method of claim 37, further including curing the liquid
crystal polymer after the step of mating the first major surface of
a semiconductor chip to the liquid crystal polymer.
39. A semiconductor component, comprising: a heatsink having first
and second major surfaces; a liquid crystal polymer disposed on the
first major surface of the heatsink, the liquid crystal polymer
having a first side; first and second leadframe leads disposed on
first and second portions of the liquid crystal polymer,
respectively; a semiconductor chip having an active surface and a
back surface, the active surface coupled to the heatsink; an
interconnect coupling the semiconductor chip to the first leadframe
lead; and a clip coupling the back surface to the second leadframe
lead.
40. The semiconductor component of claim 39, wherein a portion of
the first leadframe lead extends beyond the first side of the
liquid crystal polymer.
41. The semiconductor component of claim 40, wherein the liquid
crystal polymer forms a ring-shaped pattern on the first major
surface of the heatsink, the ring-shaped pattern comprising first,
second, third, and fourth sides, wherein the first and second sides
are opposite each other and the third and fourth sides are opposite
each other, and wherein the first side includes the first portion
of the liquid crystal polymer and the second side includes the
second portion of the liquid crystal polymer.
42. The semiconductor component of claim 41, further including a
lid coupled to the first and second leadframe leads through an
electrically insulating material.
43. The semiconductor component of claim 42, wherein the lid
contacts the clip.
44. The semiconductor component of claim 43, further including at
least one fin extending from the second major surface of the
heatsink.
Description
FIELD OF THE INVENTION
[0001] The present invention relates, in general, to a
semiconductor component and, more particularly, to a semiconductor
component package.
BACKGROUND OF THE INVENTION
[0002] Semiconductor component manufacturers are constantly
striving to increase the performance of their products, while
decreasing their cost of manufacture. A cost intensive area in the
manufacture of semiconductor components is packaging the
semiconductor chips that contain the semiconductor devices. As
those skilled in the art are aware, discrete semiconductor devices
and integrated circuits are fabricated in wafers, which are then
singulated or diced to produce semiconductor chips. One or more
semiconductor chips are placed in a package to protect them from
environmental and physical stresses.
[0003] Packaging semiconductor chips increases the cost and
complexity of manufacturing semiconductor components because the
packaging designs must not only provide protection, they must also
permit transmission of electrical signals to and from the
semiconductor chips and removal of heat generated by the
semiconductor chip.
[0004] Accordingly, it would be advantageous to have a
semiconductor package for dissipating heat from a semiconductor
chip and a method for manufacturing the semiconductor package that
is cost and time efficient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The present invention will be better understood from a
reading of the following detailed description, taken in conjunction
with the accompanying drawing figures, in which like reference
numbers designate like elements and in which:
[0006] FIG. 1 is a flow diagram for manufacturing a semiconductor
component package in accordance with an embodiment of the present
invention;
[0007] FIG. 2 is a top view of a heatsink in accordance with an
embodiment of the present invention;
[0008] FIG. 3 is a top view of a leadframe over annular or
ring-shaped regions of liquid crystal polymer in accordance with an
embodiment of the present invention;
[0009] FIG. 4 is a top view of the leadframe of FIG. 2 coupled with
a heatsink prior to singulation;
[0010] FIG. 5 is a cross-sectional side view of a singulated
semiconductor packaging substrate in accordance with an embodiment
of the present invention;
[0011] FIG. 6 is a cross-sectional side view of a semiconductor
component including a semiconductor chip coupled to the singulated
semiconductor packaging substrate of FIG. 5 in accordance with an
embodiment of the present invention;
[0012] FIG. 7 is a top view of the semiconductor component of FIG.
6;
[0013] FIG. 8 is a cross-sectional side view of the semiconductor
component of FIG. 6 having a lid mounted thereon;
[0014] FIG. 9 is a top view of a semiconductor component in
accordance with another embodiment of the present invention;
[0015] FIG. 10 is a cross-sectional side view of a semiconductor
component in accordance with yet another embodiment of the present
invention; and
[0016] FIG. 11 is a top view of a semiconductor component in
accordance with yet another embodiment of the present
invention.
DETAILED DESCRIPTION
[0017] FIG. 1 is a flow diagram 10 for manufacturing a
semiconductor component package in accordance with an embodiment of
the present invention. In a beginning step (reference number 12), a
plurality of heatsinks are manufactured using, for example, an
injection mold batch process. Typically, each heatsink of the
plurality of heatsinks has a quadrilateral shape. It should be
understood that the shaped of each heatsink is not a limitation of
the present invention. As those skilled in the art are aware,
injection molding technology allows for the manufacture of
heatsinks having various shapes and dimensions. In another
beginning step (reference number 14), a leadframe having a
plurality of leadframe leads is provided. By way of example, the
leadframe is configured to have a plurality of sets of leadframe
leads, where one set is associated with a single or corresponding
heatsink. In one embodiment, each set is comprised of two leadframe
leads that are spaced apart from each other and are for coupling to
opposing sides of the quadrilaterally shaped heatsink using a
liquid crystal polymer. The liquid crystal polymer is dispensed or
extruded on the leadframe to form a plurality of square shaped
rings of polymeric material. One of the square shaped rings
corresponds to a set of the leadframe leads, wherein one side of
the square shaped ring of polymer is on one leadframe lead and an
opposite side of the square shaped ring of polymer is on the other
leadframe lead of a set two leadframe leads (reference number 16).
Leadframe leads having liquid crystal polymer disposed thereon are
further described with reference to FIG. 3.
[0018] In accordance with one embodiment, after dispensing the
liquid crystal material on the leadframe leads, it is partially
cured (reference number 18) by exposing it to heat at a temperature
ranging from about 260.degree. C. to about 280.degree. C. for a
time period ranging from about 20 minutes to about 60 minutes under
low pressure. A low pressure is a pressure of less than 1,000
pounds per square inch (psi), or less than 6895 kiloPascals (kPa).
By way of example, the liquid crystal polymer is partially cured at
a pressure of about 100 psi (i.e., about 689 kPa). The partial
curing step sufficiently solidifies the liquid crystal material so
that it maintains its form while making the liquid crystal polymer
tacky or sticky.
[0019] The liquid crystal material is positioned on or mated with
the heatsinks (reference number 20). Because the partial curing
step makes the liquid crystal polymer tacky, it sticks to the
heatsink, thereby coupling the leadframe leads to the heatsink.
Preferably, mating the liquid crystal material with the heatsinks
occurs while the heatsinks are still positioned in the molds in
which they were cast.
[0020] The leadframe leads and heatsinks are pressed together by
applying pressure to one or both of them and the liquid crystal
material is fully cured (reference number 22) by exposing it to
heat at a temperature ranging from about 280.degree. C. to about
300.degree. C. for a time period ranging from about 20 minutes to
about 60 minutes under low pressure, e.g., about 100 psi (i.e.,
about 689 kPa). After fully curing the liquid crystal polymer, the
plurality of heatsinks, leadframe leads, and liquid crystal polymer
form a unitary packaging structure comprising a plurality of
packaging substrates. The unitary packaging structure is singulated
into individual packaging substrates using, for example, sawing or
laser cutting (reference number 24).
[0021] FIG. 2 is a top view of a bottom portion 50 of a mold
assembly for forming heatsinks. It should be understood that the
mold assembly comprises top and bottom portions that are clamped
together to form mold cavities into which a heatsink material such
as, for example, copper, is injected to form the heatsinks. Bottom
portion 50 comprises a plurality of cavities 52A-52D, 54A-54D,
56A-56D, and 58A-58D for forming heatsinks. A runner 60 having
feeder lines 62 and 64 is coupled to cavities 52A-52D. Feeder line
62 couples runner 60 to cavities 52A and 52B and feeder line 64
couples runner 60 to cavities 52C and 52D. A runner 66 having
feeder lines 68 and 70 is coupled to cavities 54A-54D. Feeder line
68 couples runner 66 to cavities 54A and 54B and feeder line 70
couples runner 66 to cavities 54C and 54D. A runner 72 having
feeder lines 74 and 76 is coupled to cavities 56A-56D. Feeder line
74 couples runner 72 to cavities 56A and 56B and feeder line 76
couples runner 72 to cavities 56C and 56D. A runner 78 having
feeder lines 80 and 82 is coupled to cavities 58A-58D. Feeder line
80 couples runner 78 to cavities 58A and 58B and feeder line 82
couples runner 78 to cavities 58C and 58D. After clamping a top
portion (not shown) of a mold assembly with bottom portion 50 and
injecting the heatsink material into the mold assembly, heatsinks
88 are formed. Techniques for forming heatsinks using processes
such as injection molding are known to those skilled in the
art.
[0022] After forming heatsinks 88, the top portion of the mold
assembly is removed and a heatsink 88 having a platform 89 remains
in each of cavities 52A-52D, 54A-54D, 56A-56D, and 58A-58D. It
should be noted that platform 89 is an optional feature of heatsink
88 and is formed by including a cavity in the top portion (not
shown) of the mold assembly.
[0023] Referring now to FIG. 3, a top view of a leadframe 100 over
annular or ring-shaped regions 132 of liquid crystal polymer is
illustrated. Leadframe 100 has a rail 102 coupled to a rail 104 by
a plurality of ribs 106 which are substantially perpendicular to
rails 102 and 104. Each rib 106 has a plurality of leadframe leads
128 and 130 that extend from and are perpendicular to ribs 106.
Leadframe 100 is configured such that a lead 128 and a lead 130
form a pair of leads extending in opposite directions from a common
portion of rib 106. In accordance with one embodiment of the
present invention, each rib 128 is longer than each rib 130.
Preferably leadframe 100 is a copper leadframe. Other suitable
materials for leadframe 100 include iron nickel alloys. Techniques
for manufacturing leadframes are known to those skilled in the
art.
[0024] A liquid crystal polymer is dispensed in annular or
ring-shaped patterns to form a plurality of ring-shaped dielectric
structures 132 over portions of a bottom side of leadframe 100.
Ring-shaped dielectric structures 132 are thermally conductive, but
electrically non-conductive. More particularly, each ring-shaped
dielectric structure is a quadrilateral structure having opposing
walls 134 and 136 and opposing walls 138 and 140. The portion of
the liquid crystal polymer forming wall 134 is disposed on a
central portion of leadframe lead 128, i.e., the liquid crystal
polymer is spaced apart from an end 129 of leadframe lead 128. The
portion of the liquid crystal polymer forming wall 136 is disposed
adjacent an end 131 of leadframe lead 130. Preferably, end 131 of
leadframe lead 130 is aligned with an edge of wall 136. However,
the positioning of wall 136 on leadframe leads 128 and 130 are not
limitations of the present invention. The liquid crystal polymer is
partially cured by exposing it to heat at a temperature ranging
from about 260.degree. C. to about 280.degree. C. for a time period
ranging from about 20 minutes to about 60 minutes under low
pressure, e.g., 100 psi (i.e., about 689 kPa). As described with
reference to FIG. 1, the partial curing step sufficiently
solidifies the liquid crystal material so that it maintains its
form and makes it tacky or sticky.
[0025] Referring now to FIG. 4, leadframe 100 having the liquid
crystal polymer disposed thereon is mated with heatsinks 88. What
is shown in FIG. 4 are heatsinks 88 positioned in bottom portion 50
of the mold assembly and leadframe 100 coupled to the plurality of
heat sinks 88. For the sake of clarity, the exposed portions of
bottom portion 50 of the mold assembly and runners 60, 66, and 72
are cross-hatched, wherein the cross-hatches for bottom portion 50
rise from left to right and the cross-hatches for runners 60, 66,
and 72, rise from right to left, i.e., the cross-hatches are in
different directions. Pressure is applied to either the leadframe,
the heatsink, or both, and the liquid crystal polymer is cured by,
for example, being heated to a temperature ranging from about
280.degree. C. to about 300.degree. C. for a time period ranging
from about 20 minutes to about 60 minutes under low pressure, e.g.,
100 psi (i.e., about 689 kPa). Curing the assembly forms a
packaging structure or packaging frame 140, i.e., the combination
of leadframe 100, liquid crystal polymer 132, and heatsinks 88.
[0026] Referring now to FIG. 5, packaging structure 140 is
singulated by, for example, sawing or laser trimming, to form
individual packaging substrates 142. What is shown in FIG. 5 is a
cross-sectional side view of a singulated packaging substrate 142.
Each singulated packaging substrate 142 comprises leadframe leads
128 and 130 coupled to a heatsink 88 through a ring-shaped liquid
crystal polymer structure 132. Optionally, heatsink 88 has a
platform 89 that extends about 30 mils above major surface 90 and
serves as a chip receiving area.
[0027] FIG. 6 is a cross-sectional side view of a semiconductor
component 150 having a semiconductor chip 152 mounted to platform
89 in accordance with an embodiment of the present invention. What
is shown in FIG. 6 is a singulated packaging substrate 142 as
described with reference to FIG. 5 having semiconductor chip 152
mounted thereon. Semiconductor chip 152 has opposing surfaces 154
and 156 and is joined with platform 89 of singulated packaging
substrate 142. In accordance with one embodiment, semiconductor
chip 152 is a Radio Frequency (RF) power transistor in which a gate
structure 158 is formed on a peripheral portion 160 of
semiconductor chip 152 and a source region 162 is formed from a
central portion of semiconductor chip 152. Gate structure 158
comprises a gate dielectric disposed on surface 154 and a gate
conductor disposed on the gate dielectric. A contact 168 is formed
on source region 162. Suitable metallization systems for contact
168 include a titanium-nickel-gold alloy or a titanium-nickel
silver alloy. Contact 168 is soldered to platform 89. An end 172 of
a microstrip line 170 is soldered to gate structure 158 and an
opposing end 174 of microstrip line 170 is soldered to leadframe
lead 128. Suitable materials for microstrip line 170 include gold
plating on a ceramic substrate, gold plating over metal on a liquid
crystal polymer substrate, or the like. Although gate structure 158
is described as being coupled to leadframe lead 128 by bonding a
microstrip line 170 to its bottom surface, this is not a limitation
of the present invention. For example, gate structure 158 can be
coupled either to the top or bottom of leadframe lead 128 by an
electrically conductive clip or the like. Preferably, the means for
coupling gate structure 158 to leadframe lead 128 matches the
impedance at gate structure 158 to reduce reflections of the
electrical signal.
[0028] A central portion of surface 156 serves as a drain 164 of RF
power transistor 152. Optionally, the central portion of
semiconductor chip 152 is thinned from surface 156 into
semiconductor chip 152 during wafer processing, thereby forming a
lip 166 along the periphery of surface 156. Thinning the central
portion of semiconductor chip 152 improves the transfer of heat
away from semiconductor chip 152, but makes it more fragile.
Forming lip 166 from back surface 156 increases the structural
integrity of semiconductor chip 152. A contact 176 is formed on
drain region 164. Suitable metallization systems for contact 176
include an aluminum layer having a nickel-gold alloy disposed
thereon or an aluminum layer having a nickel-silver alloy disposed
thereon.
[0029] An end 182 of a clip 180 is soldered to drain contact 176
and an end 184 of clip 180 is soldered to leadframe lead 130. By
way of example, clip 180 comprises a copper-tungsten alloy. The
means for coupling leadframe lead 130 to drain contact 176 is not
limited to being a clip. For example, the coupling means includes a
solder connection, wirebonding techniques, lead bonding techniques,
or the like.
[0030] Briefly referring to FIG. 7, a top view of semiconductor
component 150 is illustrated. What is shown in FIG. 7 is leadframe
leads 128 and 130 coupled to square-shaped heatsink 88 through
ring-shaped dielectric structure 132. Semiconductor chip 152 is
soldered to platform 89 (shown in FIG. 6) and gate structure 158 is
electrically coupled to leadframe lead 128 by microstrip line 170.
Drain contact 176 is coupled to leadframe lead 130 by clip 180.
[0031] Referring now to FIG. 8, a cross-sectional side view of a
semiconductor component 200 comprising a component 150 (shown in
FIGS. 6 and 7) having a lid 202 in accordance with another
embodiment of the present invention is shown. An adhesive material
204 such as, for example, an epoxy adhesive, is dispensed on the
exposed portions of ring-shaped dielectric structure 132 and the
portions of leadframes 128 and 130 over ring-shaped dielectric
structure 132. Lid 202 has opposing surfaces 206 and 208 and is
bonded to component 150 through adhesive material 204. Optionally,
lid 202 has a plurality of fins 210 extending from surface 208. Lid
202 and fins 210 may be formed as a unitary structure using a
molding technique. Suitable materials for lid 202 include aluminum
nitride, copper, aluminum, metal matrix composite material, silicon
carbide, or the like. It should be understood that the structure of
fins 210 is not a limitation of the present invention. Fins 210 may
be comprised of a plurality of rectangular shaped extensions
protruding from surface 208, a plurality of pin-like structures
protruding from surface 208, a plurality of pyramidal-shaped
structures protruding from surface 208, or the like.
[0032] FIG. 9 illustrates a top view of a semiconductor component
250 comprising a packaging substrate 252 on which a plurality of
semiconductor chips are mounted. The plurality of semiconductor
chips communicate with each other, thereby forming a
system-in-a-package. Packaging substrate 252 is similar to
packaging substrate 142 described with reference to FIGS. 2-5;
however, it has a plurality of semiconductor chips disposed thereon
and a plurality of leads extending from each side rather than a
single lead extending from each of two opposing sides of the
heatsink. Thus, the steps for manufacturing packaging substrate 252
are similar to those for manufacturing packaging substrate 142,
except that a plurality of leads are coupled to each side of the
heatsink through the liquid crystal polymer. In addition, a
platform such as platform 89 may be on a different portion of the
heatsink or platform 89 may be absent from the heatsink. Packaging
substrate 252 includes a heatsink 254 having a quadrilateral shape
that may be formed using a mold assembly and process similar to the
mold assembly and process described with reference to FIG. 2.
[0033] A leadframe having leads on which liquid crystal polymer is
dispensed in an annular or ring-shaped pattern is provided. The
leadframe on which the liquid crystal polymer is dispensed is
similar to leadframe 100 described with reference to FIG. 3, except
that the leadframe has five leadframe leads extending from each
side rather than a single leadframe lead extending from each of two
opposing sides. Leadframe leads 256-260 and 266-270 extend from
opposing sides of the leadframe and leadframe leads 261-265 and
271-275 extend from opposing sides of the leadframe. Briefly
referring to FIG. 3, leadframe 100 has two leadframe leads
extending from opposing sides at each location having leadframe
leads. It should be understood that the number of leadframe leads
is not a limitation of the present invention. In other words, there
may be more than five leadframe leads extending from each side or
fewer than five leadframe leads extending from each side. What's
more, the number of leads extending from each leadframe side do not
have to be the same. Thus, for example, a quadrilaterally shaped
heatsink may have one side with three leadframe leads, two sides
with four leadframe leads, and the fourth side with five leadframe
leads.
[0034] Referring again to FIG. 9, the liquid crystal polymer forms
a ring-shaped dielectric structure such as structure 278 over the
bottom side of leadframe leads 256-275. Although leadframe leads
256-275 are shown as not extending over the edges of ring-shaped
dielectric structure 278 and into its central portion, this is not
a limitation of the present invention. It may be desirable for one
or more of the ends of leadframe leads 256-275 to extend over the
edges of ring-shaped dielectric structure 278 similar to leadframe
leads 128 described with reference to FIG. 5. Like packaging
substrate 142, the liquid crystal polymer of ring-shaped dielectric
structure 278 is partially cured at a temperature ranging from
about 260.degree. C. to about 280.degree. C. for a time ranging
from about 20 minutes to about 60 minutes. Leadframe leads 256-275
and ring-shaped dielectric polymer structure 278 are mounted to
heatsink 254. After mounting, the liquid crystal polymer of
dielectric structure 278 is cured at a temperature ranging from
about 280.degree. C. to about 300.degree. C. for a time ranging
from about 20 minutes to about 60 minutes under low pressure, e.g.,
about 100 psi (689 kPa).
[0035] In accordance with one embodiment, the plurality of
semiconductor chips mounted to heatsink 254 include an RF power
transistor 280, a switching device 282, and a mixed signal
integrated circuit 284. The backside or non-active side of each
chip may be electrically coupled to heatsink 254 or the backsides
of semiconductor chips 280, 282, and 284 may be coupled to heatsink
254 through an insulating material such as, for example, liquid
crystal polymer. Leadframe leads 256-275 are coupled to portions of
semiconductor chips 280, 282, and 284 using, for example, wirebonds
or clips. It should be understood that the choice of which
leadframe leads 256-275 to couple to a semiconductor chip and to
which bond pads (not shown) on the semiconductor chip is a design
choice. It should be further understood that the chips may be
coupled to each other by, for example, wirebonding. For the sake of
clarity, the wirebonds have not been shown in FIG. 9.
[0036] Optionally, a lid such as, for example, lid 202, can be
mounted on packaging substrate 250.
[0037] Referring now to FIG. 10, a cross-sectional side view of a
semiconductor component 300 in accordance with another embodiment
of the present invention is shown. Semiconductor component 300
comprises a semiconductor chip 302 coupled to a heatsink 304 and a
ball grid array substrate 306 having solder balls bonded to a back
surface. Semiconductor chip 302 has an active surface 308 on which
bumped bond pads 310 are formed and a surface 312 suitable for
mating with heatsink 304. Heatsink 304 comprises a base 314 having
sidewalls 316. Base 314 has a chip mating surface 317 and a heat
dissipation surface 318. Preferably, heat dissipation surface 318
has a plurality of pyramidally shaped fins 320 extending therefrom.
By way of example, heatsink 304 is formed by injection molding
using techniques described with reference to FIG. 2 for making
heatsink 88; however, the bottom portion of the mold assembly
includes means for forming fins 320.
[0038] Semiconductor chip 302 is coupled to a ball grid array
substrate 306 via a liquid crystal polymer 322. Ball grid array
substrate 306 has a top surface 330 having landing pads 332 and a
bottom surface 334 having landing pads 336. Solder balls 338 are
disposed on landing pads 336. Landing pads 332 are configured to
mate with bumped bond pads 310 that are disposed on semiconductor
chip 302. It should be noted that FIG. 10 shows bumped bond pads
310 after bonding with corresponding landing pads 332.
[0039] Liquid crystal polymer 322 is dispensed on top surface 330
of ball grid array substrate 306. Liquid crystal polymer 322 is
partially cured at a temperature ranging from about 260.degree. C.
to about 280.degree. C. for a time ranging from about 20 minutes to
about 60 minutes under low pressure, e.g., about 100 psi (689 kPa).
The partially cured liquid crystal polymer 322 is mated with
semiconductor chip 302. The partial curing leaves liquid crystal
polymer 322 tacky which promotes adhesion with ball grid array
substrate 306. Semiconductor chip 302 is pressed against ball grid
array substrate 306 and the combination of the semiconductor chip
302, liquid crystal polymer 322, and ball grid array substrate 306
undergo a heat treatment. The heat treatment bonds bumped bond pads
310 with landing pads 332 and cures liquid crystal polymer 322,
thereby forming semiconductor component 300. It should be noted
that heatsink 304 also serves as a lid to provide protection from
physical and environmental stresses.
[0040] Referring now to FIG. 11, a top view of a semiconductor
component 350 in accordance with another embodiment of the present
invention is shown. Semiconductor component 350 includes a
packaging substrate 352 having a semiconductor chip 353 mounted
thereon. Packaging substrate 352 includes a heatsink 354 having
opposing sides 356 and 358 and opposing sides 360 and 362. Although
heatsink 354 is shown as a quadrilaterally shaped structure, this
is not a limitation of the present invention. Heatsink 354 can have
other geometric shapes.
[0041] Packaging substrate 352 includes a plurality of leadframe
leads 370-387 coupled to heatsink 354 through a thermally
conductive liquid crystal polymer 364. Prior to singulation,
leadframe leads 370-387 are part of a leadframe (not shown) in
which leadframe leads 370-374 and 379-383 are on opposing sides of
the leadframe and leads 375-378 and 384-387 are on opposing sides
of the leadframe. The number of leads and the number of leads per
side of packaging substrate 352 are not a limitation of the present
invention.
[0042] Liquid crystal polymer 364 is preferably dispensed on
leadframe leads 370-387 and partially cured by heating to a
temperature ranging from about 260.degree. C. to about 280.degree.
C. for a time ranging from about 20 minutes to about 60 minutes
under low pressure, e.g., about 100 psi (689 kPa). The partial
curing leaves liquid crystal polymer 364 tacky or sticky. The
partially cured liquid crystal polymer 364 is mated with heatsink
354. Because liquid crystal polymer 364 is tacky, it adheres to
heatsink 354. Pressure is applied to either the leadframe, the
heatsink, or both, and the liquid crystal polymer is cured by, for
example, being heated to a temperature ranging from about
280.degree. C. to about 300.degree. C. for a time period ranging
from about 20 minutes to about 60 minutes under low pressure, e.g.,
about 100 psi (689 kPa). Curing liquid crystal polymer 364 forms an
assembly containing a plurality of packaging substrates 352,
wherein each packaging substrate includes leadframe leads, liquid
crystal polymer 364, and a heatsink 354.
[0043] The assembly is singulated to form individual packaging
substrates 352. After singulation, leadframe leads 370-387 are
preferably flush with the sides of heatsink 354, i.e., leadframe
leads 370-374 are flush with side 356, leadframe leads 375-378 are
flush with side 362, leadframe leads 384-387 are flush with side
360, and leadframe leads 379-383 are flush with side 358.
[0044] Semiconductor chip 353 is mounted on heatsink 354. The
backside or non-active side of semiconductor chip 353 may be
electrically coupled to heatsink 354 or it may be coupled to
heatsink 354 through an insulating material such as, for example,
liquid crystal polymer. Leadframe leads 370-387 are coupled to bond
pads 390 disposed on semiconductor chip 353 using, for example,
wirebonds. It should be understood that the choice of which
leadframe leads 370-387 to couple to which bond pads 390 is a
design choice. For the sake of clarity, the wirebonds have not been
shown in FIG. 11.
[0045] It may be desirable to dispense a glob top material (not
shown) over semiconductor chip 353 and leadframe leads 370-387. The
glob top material can protect semiconductor chip 353 against
mechanical and environmental stresses.
[0046] Optionally, heatsink 354 has fins similar to those described
with reference to heatsink 304 shown in FIG. 10. In accordance with
another option, a lid (not shown) may be formed over semiconductor
chip 353, wherein a portion of the lid contacts a central portion
of semiconductor chip 353.
[0047] By now it should be appreciated that a semiconductor
component and a method for manufacturing the semiconductor
component have been provided. An advantage of the present invention
is that it provides a cost effective method for packaging a
semiconductor chip using batch processing steps for forming the
packaging substrate rather than using individual assembly steps.
Manufacture of semiconductor packages in accordance with the
present invention provides a high quality assembly that is
repeatable. In addition, the present invention provides for various
heatsinking finned structures for removing heat from the
semiconductor devices.
[0048] Although certain preferred embodiments and methods have been
disclosed herein, it will be apparent from the foregoing disclosure
to those skilled in the art that variations and modifications of
such embodiments and methods may be made without departing from the
spirit and scope of the invention. It is intended that the
invention shall be limited only to the extent required by the
appended claims and the rules and principles of applicable law.
* * * * *