U.S. patent application number 15/084893 was filed with the patent office on 2016-07-21 for constrained die adhesion cure process.
The applicant listed for this patent is GLOBALFOUNDRIES Inc.. Invention is credited to Edmund Blackshear, Vijayeshwar D. Khanna, Oswald J. Mantilla.
Application Number | 20160211161 15/084893 |
Document ID | / |
Family ID | 52004165 |
Filed Date | 2016-07-21 |
United States Patent
Application |
20160211161 |
Kind Code |
A1 |
Blackshear; Edmund ; et
al. |
July 21, 2016 |
CONSTRAINED DIE ADHESION CURE PROCESS
Abstract
A clamping apparatus applies a force to a workpiece during
processing. The clamping apparatus includes a base defining a work
area configured to receive a joined structure having multiple
elements. The base defines a recess in the work area. An adjustable
mechanism is configured to releasably couple to the base and apply
a adjustable downward force to the joined structure to bend the
joined structure downwardly into the recess during a process. A
resilient plunger is part of the adjustable mechanism. The
resilient plunger extends downwardly from a top plate of the
adjustable mechanism, and the resilient plunger is configured to
contact a top of a first element of the joined structure to apply
the downward force.
Inventors: |
Blackshear; Edmund;
(Wappingers Falls, NY) ; Khanna; Vijayeshwar D.;
(Millwood, NY) ; Mantilla; Oswald J.; (Wappingers
Falls, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GLOBALFOUNDRIES Inc. |
Grand Cayman |
|
KY |
|
|
Family ID: |
52004165 |
Appl. No.: |
15/084893 |
Filed: |
March 30, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13910152 |
Jun 5, 2013 |
9305894 |
|
|
15084893 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 24/75 20130101;
H01L 2224/75703 20130101; H01L 21/687 20130101; H01L 2224/73204
20130101; Y10T 29/49998 20150115; H01L 21/67092 20130101; Y10T
29/49826 20150115 |
International
Class: |
H01L 21/687 20060101
H01L021/687; H01L 21/67 20060101 H01L021/67 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. A method of manufacturing a clamping apparatus for applying a
force to a workpiece during processing, comprising the steps of:
defining a work area in a base, the work area being configured to
receive a joined structure having multiple elements; creating a
recess in the work area of the base; and attaching a resilient
plunger extending downwardly from a top plate of an adjustable
mechanism, the resilient plunger being configured to contact a top
of a first element of the joined structure to apply an adjustable
downward force, the adjustable mechanism being releasably couplable
to the base for applying the adjustable downward force to the
joined structure to bend the joined structure downwardly into the
recess during a process.
13. The method of claim 12, wherein the resilient plunger includes
an end plate coupled to a distal end thereof.
14. The method of claim 12, wherein the plunger includes a
contoured end plate coupled to a distal end thereof, the end plate
configured to contact the top of the first element of the joined
structure.
15. The method of claim 12, wherein the plunger includes a convex
or a concave end plate coupled to a distal end thereof, the end
plate configured to contact the top of the first element of the
joined structure.
16. The method of claim 12, wherein the plunger includes a dome
shaped end plate coupled to a distal end thereof, the end plate
configured to contact the top of the first element of the joined
structure.
17. The method of claim 12, wherein the adjustable mechanism and
the resilient plunger are configured to selectively apply and
release the downward force to the joined structure.
18. The method of claim 12, wherein the adjustable mechanism
includes a locked position wherein side flanges attached to
opposite ends of the top plate are releasable coupled to mating
ledges of the base to apply the adjustable downward force to the
joined structure, and the adjustable mechanism includes an unlocked
position wherein the side flanges are not coupled to the
ledges.
19. A method of applying a force to a workpiece during processing,
comprising: positioning a joined structure having multiple elements
in a work area of a base, the base defining a recess in the work
area; releasably coupling an adjustable mechanism to the base and
to apply a adjustable downward force to the joined structure to
bend the joined structure downwardly into the recess during a
process; and applying the downward force to a top of a first
element of the joined structure using a resilient plunger being
part of the adjustable mechanism, the resilient plunger extending
downwardly from a top plate of the adjustable mechanism to contact
the top of the first element apply the downward force.
20. The method of claim 19, further comprising: locking the
adjustable mechanism when side flanges attached to opposite ends of
the top plate are releasable coupled to mating ledges of the base
to apply the adjustable downward force to the joined structure; and
unlocking the adjustable mechanism when the side flanges are not
coupled to the ledges.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/910,152 filed Jun. 5, 2013 for "CONSTRAINED DIE
ADHESION CURE PROCESS" the entire contents and disclosure of which
is expressly incorporated by reference herein. This application and
the aforesaid U.S. patent application Ser. No. 13/910,152 are
related to the following commonly-owned U.S. Patent Application
filed on Jun. 5, 2013, the entire contents and disclosure of which
is expressly incorporated by reference herein: U.S. patent
application Ser. No. 13/910,169, for "LAMINATE PERIPHERAL CLAMPING
TO CONTROL MICROELECTRONIC MODULE BSM WARPAGE".
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to a clamping apparatus and
method for clamping a workpiece during processing.
[0004] 2. Background of the Disclosure
[0005] An example process in the field of semiconductor
manufacturing includes the process of dispensing underfill material
between a chip die and a substrate such as a laminate in Flip Chip
manufacturing. The laminate may include a thin core or coreless
organic laminate. Underfill reduces the effects of mismatched
coefficients of thermal expansion (CTE) between the die and
laminate materials. Therefore, after curing of the underfill, the
substrate or laminate is very susceptible to warping. For example,
the laminate material can warp when cooling from a cure
temperature. Warping is undesirable because it can lead to die
cracking, thermal interface material (TIM) tearing, and ball grid
array (BGA) coplanarity failure. All of which are unacceptable in
meeting chip quality control standards.
[0006] Further, fabrication of organic flip chip electronic modules
typically includes a chip join reflow on a laminate, such as a
thin-laminate organic circuit board, for example, a printed wiring
board (PWB) or printed circuit board (PCB). During fabrication of
an organic flip chip electronic module, particularly those modules
using thin core and coreless organic laminates, undesirable warpage
of the laminate can be a problem. Undesirable die stresses can also
result from variations in the laminate shape during reflow.
Undesirable laminate warpage can also occur during processing of a
chip/die and a laminate, for example, during flip chip fabrication
which can present itself in a variety of shapes and each shape can
affect the process in a different way. Die stresses can manifest
themselves as a cracked die, or separations of the dielectric
layers within the die (e.g., typically, white bumps). Increased
laminate warpage (also referred to as warping) during die reflow
can also lead to increased module warpage at the end of a bond and
assembly process, which can cause the module to fail final
co-planarity specifications.
[0007] Laminate warpage or warping may be defined by the laminate's
curvature from a flat surface of the bottom of the laminate.
Alternatively, laminate warpage may be defined by a planar surface
mating with the bottom of the laminate, thereby providing a
horizontal plane to reference any warping of the laminate.
BRIEF SUMMARY
[0008] It would be desirable to reduces the warping of substrates
such as a laminate after curing of the a joined structure including
the laminate. It would therefore also be desirable to provide an
apparatus and method for constraining a laminate and a joined
structure or joined die.
[0009] In an embodiment of the present invention, a clamping
apparatus applies a force to a workpiece during processing. The
clamping apparatus includes a base defining a work area configured
to receive a joined structure having multiple elements. The base
defines a recess in the work area. An adjustable mechanism is
configured to releasably couple to the base and apply a adjustable
downward force to the joined structure to bend the joined structure
downwardly into the recess during a process. A resilient plunger is
part of the adjustable mechanism. The resilient plunger extends
downwardly from a top plate of the adjustable mechanism, and the
resilient plunger is configured to contact a top of a first element
of the joined structure to apply the downward force.
[0010] In another embodiment of the present invention, a method of
manufacturing a clamping apparatus for applying a force to a
workpiece during processing includes the steps of: defining a work
area in a base, wherein the work area is configured to receive a
joined structure having multiple elements; creating a recess in the
work area of the base; attaching a resilient plunger extending
downwardly from a top plate of an adjustable mechanism. The
resilient plunger is configured to contact a top of a first element
of the joined structure to apply an adjustable downward force, and
the adjustable mechanism is releasably couplable to the base for
applying the adjustable downward force to the joined structure to
bend the joined structure downwardly into the recess during a
process.
[0011] In another embodiment of the present invention, a method of
applying a force to a workpiece during processing includes:
positioning a joined structure having multiple elements in a work
area of a base, wherein the base defines a recess in the work area;
releasably coupling an adjustable mechanism to the base and to
apply a adjustable downward force to the joined structure to bend
the joined structure downwardly into the recess during a process;
and applying the downward force to a top of a first element of the
joined structure using a resilient plunger being part of the
adjustable mechanism, the resilient plunger extending downwardly
from a top plate of the adjustable mechanism to contact the top of
the first element apply the downward force.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0012] These and other objects, features and advantages of the
present invention will become apparent from the following detailed
description of illustrative embodiments thereof, which is to be
read in connection with the accompanying drawings. The various
features of the drawings are not to scale as the illustrations are
for clarity in facilitating one skilled in the art in understanding
the invention in conjunction with the detailed description. In the
drawings:
[0013] FIG. 1 is an isometric view of a base for a clamping
apparatus, according to according to an embodiment of the
disclosure;
[0014] FIG. 2 is an isometric view of the base shown in FIG. 1
holding a joined structure;
[0015] FIG. 3 is an isometric view of the clamping apparatus
including the base shown in FIGS. 1 and 2, according to an
embodiment of the disclosure, wherein an adjustable mechanism is
attached to the base in an unlocked position;
[0016] FIG. 4 is an isometric view of the clamping apparatus as
shown in FIG. 3, wherein the adjustable mechanism is in a locked
position;;
[0017] FIG. 5 is a isometric view of a rectangular end plate
according to an embodiment of the disclosure;
[0018] FIG. 6 is a isometric view of a circular end plate according
to an embodiment of the disclosure;
[0019] FIG. 7 is a isometric view of a dome shaped end plate
according to an embodiment of the disclosure;
[0020] FIG. 8 is a side elevational view of a joined structure
before a curing process, according to the prior art;
[0021] FIG. 9 is a side elevational view of a joined structure of
FIG. 8 after the curing process, according to the prior art;
[0022] FIG. 10 is a side elevational view of a joined structure
before a curing process, according to an embodiment of the
disclosure; and
[0023] FIG. 11 is a side elevational view of the joined structure
of FIG. 10 after the curing process, according to an embodiment of
the disclosure.
DETAILED DESCRIPTION
[0024] Referring to FIGS. 1-4, a clamping apparatus 100 according
to an embodiment of the invention for applying a force to a
workpiece during processing is discussed below. The apparatus 100
(shown in FIG. 3) includes a base 10 defining multiple work areas
12 configured to each receive a joined structure having multiple
elements. The elements of the apparatus may be applied to a single
workpiece using a single work area, or may have multiple work areas
or be a multi module apparatus or fixture, as in the embodiment
shown herein. The present disclosure may refer to the apparatus
elements singularly, however, it is understood that the elements
may be duplicated in a multi work area apparatus as in the
embodiment of the present disclosure. In the embodiment of the
present disclosure, the joined structure is a joined die 50 (shown
in FIG. 2) which includes a semiconductor chip 54 on a laminate 58.
The laminate can be an embodiment of a substrate for a joined
structure, and can be a coreless laminate. The base 10 includes a
recess 14 in the work area 12. A frame 70 is received by the base
10 and work area 12. The frame 70 includes a receiving area for
receiving the joined die 50. The receiving area of the frame 70 may
include a central recessed portion such that the joined die 50 is
received in a central recessed portion and flush with a perimeter
of the frame 70.
[0025] Referring to FIGS. 3 and 4, an adjustable mechanism 104
includes a plate 110 having resilient plungers (also can be
referred to as resilient members) embodied as springs 120 attached
thereto. The adjustable mechanism 104 removably couples to the base
10 using opposing flanges 112 attached to opposing ends of the
plate 110. The flanges 112 include attachment pins 114 for
removably attaching the adjustable mechanism 104 to the base. The
pins 114 are threaded into the base in aligning threaded holes.
[0026] The springs 120 are aligned over the chips 54. The distal
ends of the springs 120 mate with an end plate 130. The combination
of the spring 120 and the end plate 130 form a resilient plunger
which can be used to apply a downward force to the die. The end
plate 130 may have a predetermined shape, for example, a contour to
provide an appropriate distribution of force across the die
surface. For example, planar, convex, concave, or domed shaped. The
controlled magnitude and direction of the force is applied to the
top of the die using the end plate of the plunger. The amount of
the force applied to the die is determined by how much biasing
(bending) is desired of the joined structure to achieve the post
curing affect desired. Further, the biasing or bending of the
joined structure is designed to compensate for the post curing
warping that occurs to achieve a flattening and a substantially
planar structure after cooling from the curing process.
[0027] The adjustable mechanism 104 is shown being positioned in
FIG. 3, before it is in its locked position which is shown in FIG.
4. The locked position is achieved when the pins 114 are completely
threaded into the holes such that the flanges 112 rest on the
ledges 16 of the base 10, as shown in FIG. 4, and the plate 110
thereby applies a downward force 140 to the springs 120. In the
locked position of the apparatus 100 shown in FIG. 4, the springs
120 apply the downward force 140 to the top of the die 54 via the
end plate 130. The force applied to the die is distributed across
the joined structure (or package surface), that is, the laminate.
The joined structure, i.e., the laminate 58 and die 54 are bent or
flexed downwardly as shown in FIG. 10. For example, the laminate of
the joined structure may be bent downwardly about 50 microns from a
horizontal plane. The downwardly applied force 140 can also be
described as bending the structure into a preflexed or prestressed
or biased shape. The apparatus 100 with the joined structure can be
processed, for example, in a processing chamber. The process can be
an underfill (resin material) cure process, wherein a material is
positioned between the die and the laminate. After underfill is
dispensed it requires a bake operation to cure the resin or
material. Underfilling with a material reduces the effects of a
mismatch of coefficients of thermal expansion (CTE) between the die
and laminate materials during curing. Cooling after the curing
process can results in warping of a substrate, for example, the
laminate 58.
[0028] The curing process can have a temperature of about 150
degrees Celsius. The biased laminate 58 shown in FIG. 10, is thus
processed at temperatures of about 150 degrees Celsius. After
cooling from the processing, the laminate bends or warps. However,
as a result of the biasing of the joined structure using the
clamping apparatus, the laminate is substantially flat as shown in
FIG. 11. Thus, the pre biasing of the joined structure results in a
substantially planar end product after processing, in this case, a
joined laminate and die, by restricting the warp effects of
underfill curing.
[0029] The adjustable mechanism 104 is adjustable over the base by
adjusting the pins 114 in the threaded holes on the ledges of the
base. When the pins 114 are fully threaded and the flanges 112 are
in contact with the ledges 16 of the base 10, the adjustable
mechanism is in the locked position, to apply the downward force to
the joined structure. The adjustable mechanism is in an unlocked
position when the side flanges 112 of the mechanism 104 are not
coupled to the ledges 16 of the base 10.
[0030] The end plate may be a selected shape to facilitate the
joining processes and to maintain a consistent pressure on the die
when the die flexes with the laminate. For example, a planar end
plate 200 or a circular end plate 204 as shown in FIGS. 5 and 6 may
be used. A dome shaped end plate 208 as shown in FIG. 7 may also be
used. The dome area 212 is positioned on the top of the chip 54.
Thus, when the joined structure is pre stressed or biased, the dome
fits into the contour of the die, which is now slightly convex.
[0031] One of the advantages of the present disclosure is the
reduction or elimination of warping of the laminate of the joined
structure as a result of curing the underfill between the die and
the laminate, for example during a FCBGA (Flip Chip Ball Grid
Array) semiconductor processing. The present disclosure utilizes a
downward force, a load, which is controlled by the apparatus 100 to
control the shape of the die and laminate, or a chip substrate
subassembly, during an underfill cure process. The downward force
as described in the present disclosure minimizes die camber and
module warpage resulting from underfill cure shrinkage and
differential expansion when cooling from a cure temperature.
[0032] In an alternative implementation, a load can be applied to
the laminate (or a substrate) bottom using a vacuum.
[0033] Thereby, the present disclosure provides a clamping
apparatus 100 for providing a force 140 to a workpiece, for
example, a joined structure during processing according to an
embodiment of the invention. The clamping apparatus includes the
base 10 defining the work area 12 configured to receive the joined
structure having multiple elements. The base defines a recess 14 in
the work area of the base 10. The adjustable mechanism 110 is
configured to releasably couple to the base and apply the
adjustable downward force 140 to the joined structure to bend the
joined structure downwardly into the recess during a process. The
resilient plunger 120 is part of the adjustable mechanism, and the
resilient plunger extends downwardly from a top plate 111 of the
adjustable mechanism 110. The resilient plunger is configured to
contact a top of the first element, embodied as the die 54, of the
joined structure to apply the downward force. The resilient plunger
can be embodied as the spring 120 and can include the end plate
attached to the distal end of the spring.
[0034] Further, the apparatus and method of the present disclosure
constrains the joined structure along a vertical axis, while
allowing for movement along a horizontal plane due to thermal
expansion, while biasing the joined structure as desired and
described above.
[0035] In operation, the present disclosure provides a method of
using a clamping apparatus for applying a force to a workpiece
during processing, according to an embodiment of the invention. The
method of applying a force to a workpiece during processing can
include positioning the joined structure 50 having multiple
elements, i.e., the laminate 58 and the die 54, in the work area 12
of the base 10. The method includes releasably coupling the
adjustable mechanism 110 to the base 12, to apply an adjustable
downward force to the joined structure 50 to bend the joined
structure downwardly into the recess 14 during a process. The
downward force 140 is applied to the top of the first element, that
is, the die 54, using the resilient plunger, for example the spring
120 and the end plate 130, wherein the resilient plunger extends
downwardly from the top plate 111 of the adjustable mechanism 110
to contact the top of the die and apply the downward force 140.
[0036] The adjustable mechanism is in a locked position when the
side flanges 112 attached to opposite ends of the top plate 111 are
releasable coupled to the mating ledges 16 of the base 10 to apply
the adjustable downward force to the joined structure. Thereby,
ipso facto, unlocking, or the adjustable mechanism in an unlocked
position, includes when the side flanges of the adjustable
mechanism are not coupled to the ledges.
[0037] The resilient member, that is, the spring 120 can have a
specified stiffness to exert the desired downward force.
[0038] While embodiments of the present invention has been
particularly shown and described with respect to preferred
embodiments thereof, it will be understood by those skilled in the
art that changes in forms and details may be made without departing
from the spirit and scope of the present application. It is
therefore intended that the present invention not be limited to the
exact forms and details described and illustrated herein, but falls
within the scope of the appended claims.
* * * * *