U.S. patent application number 11/512566 was filed with the patent office on 2007-03-22 for supporting plate, apparatus, and method for stripping supporting plate.
This patent application is currently assigned to Tokyo Ohka Kogyo Co., Ltd.. Invention is credited to Yoshihiro Inao, Atsushi Miyanari, Akihiko Nakamura.
Application Number | 20070062644 11/512566 |
Document ID | / |
Family ID | 37882899 |
Filed Date | 2007-03-22 |
United States Patent
Application |
20070062644 |
Kind Code |
A1 |
Nakamura; Akihiko ; et
al. |
March 22, 2007 |
Supporting plate, apparatus, and method for stripping supporting
plate
Abstract
A supporting plate which makes it possible to easily strip the
supporting plate from a substrate in a short period of time after
thinning the substrate. In the supporting plate to which a
circuit-formed surface of a substrate is bonded with an adhesive, a
first penetrating hole is formed in a substantially central portion
of the supporting plate in the thickness direction, grooves
connecting with the first penetrating hole are formed on a surface
of the supporting plate to be contacted with an adhesive, and a
second penetrating hole connecting with the grooves is formed in a
peripheral portion of the supporting plate in the thickness
direction.
Inventors: |
Nakamura; Akihiko;
(Kanagawa, JP) ; Miyanari; Atsushi; (Kanagawa,
JP) ; Inao; Yoshihiro; (Kanagawa, JP) |
Correspondence
Address: |
CARRIER BLACKMAN AND ASSOCIATES
24101 NOVI ROAD
SUITE 100
NOVI
MI
48375
US
|
Assignee: |
Tokyo Ohka Kogyo Co., Ltd.
Kawasaki-shi
JP
|
Family ID: |
37882899 |
Appl. No.: |
11/512566 |
Filed: |
August 30, 2006 |
Current U.S.
Class: |
156/703 ;
156/707; 156/755 |
Current CPC
Class: |
B29C 63/0013 20130101;
Y10T 156/1132 20150115; B29L 2031/3425 20130101; Y10T 156/1111
20150115; Y10T 156/1928 20150115 |
Class at
Publication: |
156/344 ;
156/584 |
International
Class: |
B29C 63/00 20060101
B29C063/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2005 |
JP |
2005-251200 |
Claims
1. A supporting plate to which a circuit-formed surface of a
substrate is bonded with an adhesive, wherein a first penetrating
hole is formed in a substantially central portion of the supporting
plate in the thickness direction, grooves connecting with the first
penetrating hole are formed on a surface of the supporting plate to
be contacted with an adhesive, and a second penetrating hole
connecting with the grooves is formed in a peripheral portion of
the supporting plate in the thickness direction.
2. The supporting plate according to claim 1, wherein the grooves
are in a grid, staggered, or form a honeycomb pattern.
3. The supporting plate according to claim 1, wherein the first
penetrating hole is a hole for supplying a solvent, and the second
penetrating hole is a hole for draining the solvent.
4. The supporting plate according to claim 1, wherein the second
penetrating hole is a hole for supplying a solvent, and the first
penetrating hole is a hole for draining the solvent.
5. An apparatus for stripping a supporting plate bonded to a
circuit-formed surface of a substrate with an adhesive, comprising
a plate which has a first penetrating hole formed in a
substantially central portion of the plate in the thickness
direction, a second penetrating hole formed in a peripheral portion
of the plate in the thickness direction, and a hole for attracting
a supporting plate formed between the first penetrating hole and
the second penetrating hole in the radial direction.
6. The apparatus according to claim 5, wherein the first
penetrating hole is a hole for supplying a solvent, and the second
penetrating hole is a hole for draining the solvent.
7. The apparatus according to claim 5, wherein the second
penetrating hole is a hole for supplying a solvent, and the first
penetrating hole is a hole for draining the solvent.
8. The apparatus according to claim 6, wherein the first
penetrating hole is also a hole for supplying air from an air
supplying means.
9. A method for stripping a supporting plate bonded to a
circuit-formed surface of a substrate with an adhesive by using a
plate which has a first penetrating hole formed in a substantially
central portion thereof in the thickness direction a second
penetrating hole formed in a peripheral portion thereof in the
thickness direction, and a hole for attracting the supporting plate
formed between the first penetrating hole and the second
penetrating hole in the radial direction of the plate, comprising
the steps of: supplying a solvent from outside to the first
penetrating hole of the plate and to an associated first
penetrating hole formed in a substantially central portion of the
supporting plate in the thickness direction thereof; distributing
the solvent from the first penetrating hole of the supporting plate
through grooves formed on a surface of the supporting plate in
contact with the adhesive and connecting with the first penetrating
hole of the supporting plate; dissolving the adhesive on the
surface contacted with the substrate by the solvent; and draining
the solvent used for dissolving the adhesive from a second
penetrating hole connecting with the grooves and formed in a
peripheral portion of the supporting plate in the thickness
direction and a second penetrating hole formed in a peripheral
portion of the plate.
10. The method according to claim 9, further comprising the step of
supplying air from outside to the first penetrating hole of the
plate so as to distribute the air from the first penetrating hole
of the supporting plate to the grooves which connect with the first
penetrating hole of the supporting plate after the step of
dissolving the adhesive.
11. A method for stripping a supporting plate bonded to a
circuit-formed surface of a substrate with an adhesive by using a
plate which has a first penetrating hole formed in one of a
substantially central portion and a peripheral portion thereof in
the thickness direction, a second penetrating hole formed in the
other of the substantially central portion and the peripheral
portion thereof and a hole for attracting the supporting plate
formed between the first penetrating hole and the second
penetrating hole in the radial direction of the plate, comprising
the steps of: supplying a solvent from outside to the fist
penetrating hole of the plate and to an associated first
penetrating hole formed in one of a substantially central portion
and a peripheral portion of the supporting plate in the thickness
direction thereof; distributing the solvent from the first
penetrating hole of the supporting plate to grooves formed on a
surface of the supporting plate in contact with the adhesive and
connecting with the first penetrating hole of the supporting plate;
dissolving the adhesive on the surface contacted with the substrate
by the solvent; and draining the solvent used for dissolving the
adhesive from a second penetrating hole formed in the other of the
substantially central portion and the peripheral portion of the
supporting plate of the supporting plate and the second penetrating
hole of the plate.
12. The method according to claim 11, further comprising the step
of supplying air from outside to the second penetrating hole of the
plate so as to distribute the air from the second penetrating hole
of the supporting plate to the grooves which connect with the
second penetrating hole of the supporting plate after the step of
dissolving the adhesive.
13. The supporting plate according to claim 2, wherein the first
penetrating hole is a hole for supplying a solvent, and the second
penetrating hole is a hole for draining the solvent.
14. The supporting plate according to claim 2, wherein the second
penetrating hole is a hole for supplying a solvent, and the first
penetrating hole is a hole for draining the solvent.
15. The apparatus according to claim 7, wherein the first
penetrating hole is also a hole for supplying air from an air
supplying means.
16. The supporting plate according to claim 1, including more than
one said first penetrating formed in the substantially central
portion of the supporting plate and more than one said second
penetrating formed in the peripheral portion of the supporting
plate.
17. The supporting plate according to claim 16, wherein said more
than one said second penetrating are formed in spaced relation
around the peripheral portion of the supporting plate.
18. The apparatus according to claim 5, including more than one
said first penetrating formed in the substantially central portion
of the plate and more than one said second penetrating formed in
the peripheral portion of the plate.
19. The apparatus according to claim 18, wherein said more than one
said second penetrating are formed in spaced relation around the
peripheral portion of the plate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a supporting plate which is
used when a substrate such as a semiconductor wafer is thinned, and
also relates to an apparatus and a method for stripping the
supporting plate from the semiconductor wafer.
[0003] 2. Description of the Prior Art
[0004] There is a continuing need to make IC cards and cell phones
thinner, smaller, and lighter. In order to satisfy this need,
semiconductor chips to be incorporated therein must be thin.
Although at present the thickness of a wafer which forms a
semiconductor chip is 125-150 .mu.m, it is expected that the
thickness of a semiconductor wafer must be 25-50 .mu.m for a next
generation of chips.
[0005] An example of a conventional method for thinning a
semiconductor wafer is shown in FIG. 8. Specifically, a protecting
tape is attached to a surface (A-surface) of a semiconductor wafer
on which a circuit (element) has been formed. The wafer is turned
over, and the rear surface (B-surface) of the semiconductor wafer
is ground by a grinder to make the wafer thinner. The B surface of
the semiconductor wafer which has been thinned is fixed onto a
dicing tape retained by a dicing frame, and the protecting tape
covering the surface (A-surface) of the semiconductor wafer on
which a circuit (element) has been formed is stripped in this
state. Next, the wafer is cut into each chip by a dicing
device.
[0006] The above-mentioned method has been disclosed in Document 1.
According to Document 1, the heat-resistant protecting tape is
stripped from the thinned semiconductor wafer by using a strong
adhesive tape bonded to one end of the protecting tape.
[0007] Document 2 has disclosed that a protecting base obtained by
immersing a ladder-type silicone oligomer in an aluminum
nitride--boron nitride porous sintered material is used instead of
a protecting tape, and the protecting base and a semiconductor
wafer are bonded by using a thermoplastic film. Document 2 also
mentions that they are immersed in pure water at 80.degree. C. for
3 hours before stripping.
[0008] Document 3 has disclosed that a protecting base is made of a
material having the same thermal expansion coefficient as a
semiconductor wafer such as alumina, aluminum nitride, boron
nitride, or silicon carbide.
[0009] Also, Document 3 has proposed a method in which the
protecting base and the semiconductor wafer are bonded by using a
thermoplastic resin such as polyimide, the semiconductor wafer is
thinned by a grinder, and thereafter stripping is performed by
immersing in water, amine, or a mixed solution of water and amine,
or by using steam.
[0010] [Document 1] Japanese Patent Application Publication No.
2002-270676
[0011] [Document 2] Japanese Patent Application Publication No.
2002-203821
[0012] [Document 3] Japanese Patent Application Publication No.
2001-77304
[0013] In the above-mentioned techniques, since it is difficult for
a solvent to enter between the supporting plate (protecting tape)
and the semiconductor wafer when the supporting plate (protecting
tape) is stripped from the semiconductor wafer, it takes too much
time to strip the supporting plate from the semiconductor
wafer.
[0014] Also, the thermoplastic film bonding the support plate
(protecting tape) and the semiconductor wafer often fails to
completely dissolve, and tends to be left in a state of sticking to
either the support plate or the semiconductor wafer.
[0015] If an adhesive is left as described above, cracking or
chipping of the semiconductor wafer easily occurs at the time of
stripping.
[0016] In order to solve the above problem, the present applicant
has proposed a supporting plate in which a plurality of penetrating
holes are provided in the thickness direction of the supporting
plate. FIG. 9 explains a method for stripping this supporting
plate.
[0017] According to this method, a solvent supplying plate 102 is
laid onto the upper surface of a supporting plate 100 via an O-ring
101. Next, a solvent is supplied from a solvent supplying pipe 103
to a space S surrounded by the supporting plate 100, the O-ring 101
and the solvent supplying plate 102. The solvent passes through
penetrating holes 104 formed in the supporting plate 100, dissolves
and removes an adhesive layer 105.
[0018] With the method of using a supporting plate in which a
plurality of penetrating holes are provided, it is possible to
securely remove an adhesive in a short period of time. However,
another problem arises.
[0019] As shown in FIG. 10, the solvent leaks from the periphery of
the supporting plate to the outside, and the solvent drops onto the
dicing tape, which results in a deterioration of the dicing tape in
a short period of time.
[0020] Further, efficiency of stripping is bad because part of a
new solvent supplied to the space S is withdrawn without being
utilized.
[0021] Furthermore, even if the adhesive is completely dissolved,
if a finger or the like is used as a device for stripping the
semiconductor wafer from the supporting plate, there is a strong
likelihood that the circuit-formed surface of the semiconductor
wafer will be damaged.
[0022] In order to solve the above-mentioned problems, the object
of the present invention is to provide a supporting plate which
makes it possible to easily strip the supporting plate from a
substrate in a short period of time after thinning the substrate,
and an apparatus and a method for stripping the supporting
plate.
SUMMARY OF THE INVENTION
[0023] In order to solve the above-mentioned problems, according to
the present invention, there is provided a supporting plate to
which a circuit-formed surface of a substrate is bonded with an
adhesive, wherein a first penetrating hole is formed in a
substantially central portion of the supporting plate in the
thickness direction, grooves connecting with the first penetrating
hole are formed on a surface of the supporting plate to be
contacted with an adhesive, and a second penetrating hole
connecting with the grooves is formed in a peripheral portion of
the supporting plate in the thickness direction.
[0024] Since the supporting plate of the present invention has a
first penetrating hole formed in a substantially central portion of
the supporting plate in the thickness direction, grooves formed on
a surface of the supporting plate to be contacted with an adhesive
so as to connect with the first penetrating hole, and a second
penetrating hole formed in a peripheral portion of the supporting
plate in the thickness direction so as to connect with the grooves,
it is possible to use the first penetrating hole as a hole for
supplying a solvent and the second penetrating hole as a hole for
draining the solvent. With this, when the supporting plate is
stripped from the substrate after the substrate is thinned, it is
possible to supply the solvent quickly to the whole surface of the
adhesive which bonds the substrate and the supporting plate so as
to strip the supporting plate in a short period of time.
[0025] Also, if the second penetrating hole is used as a hole for
supplying a solvent and the first penetrating hole is used as a
hole for draining the solvent, the same effect can be achieved.
[0026] There is also provided an apparatus for stripping a
supporting plate bonded to a circuit-formed surface of a substrate
with an adhesive, comprising a plate which has a first penetrating
hole formed in a substantially central portion of the plate in the
thickness direction, a second penetrating hole formed in a
peripheral portion of the plate in the thickness direction, and a
hole for attracting a supporting plate formed between the first
penetrating hole and the second penetrating hole in the radial
direction.
[0027] Since the stripping apparatus of the present invention
comprises a plate which has a first penetrating hole formed in a
substantially central portion of the plate in the thickness
direction, a second penetrating hole formed in a peripheral portion
of the plate in the thickness direction, and a hole for attracting
a supporting plate formed between the first penetrating hole and
the second penetrating hole in the radial direction, it is possible
to use the first penetrating hole as a hole for supplying a solvent
and the second penetrating hole as a hole for draining the solvent.
With this, when the supporting plate is stripped from the substrate
after the substrate is thinned, it is possible to supply the
solvent quickly to the whole surface of the adhesive which bonds
the substrate and the supporting plate so as to strip the
supporting plate in a short period of time.
[0028] Also, if the second penetrating hole is used as a hole for
supplying a solvent and the first penetrating hole is used as a
hole for draining the solvent, the same effect can be achieved.
[0029] There is also provided a method for stripping a supporting
plate bonded to a circuit-formed surface of a substrate with an
adhesive, comprising the steps of supplying a solvent from outside
to a first penetrating hole of a plate, distributing the solvent
from a first penetrating hole of a supporting plate to grooves
connecting with the first penetrating hole of the supporting plate,
dissolving the adhesive on a surface contacted with the substrate
by the solvent, and draining the solvent used for dissolving the
adhesive from a second penetrating hole of the supporting plate and
a second penetrating hole of the plate.
[0030] Since the stripping method of the present invention
comprises the steps of supplying a solvent from outside to a first
penetrating hole of a plate, distributing the solvent from a first
penetrating hole of a supporting plate to grooves connecting with
the first penetrating hole of the supporting plate, dissolving the
adhesive on a surface contacted with the substrate by the solvent,
and draining the solvent used for dissolving the adhesive from a
second penetrating hole of the supporting plate and a second
penetrating hole of the plate, it is possible to supply the solvent
quickly to the whole surface of the adhesive which bonds the
substrate and the supporting plate so as to strip the supporting
plate in a short period of time.
[0031] There is also provided a method for stripping a supporting
plate bonded to a circuit-formed surface of a substrate with an
adhesive, comprising the steps of supplying a solvent from outside
to a second penetrating hole of a plate, distributing the solvent
from a second penetrating hole of a supporting plate to grooves
connecting with the second penetrating hole of the supporting
plate, dissolving the adhesive on a surface contacted with the
substrate by the solvent, and draining the solvent used for
dissolving the adhesive from a first penetrating hole of the
supporting plate and a first penetrating hole of the plate.
[0032] Since the stripping method of the present invention
comprises the steps of supplying a solvent from outside to a second
penetrating hole of a plate, distributing the solvent from a second
penetrating hole of a supporting plate to grooves connecting with
the second penetrating hole of the supporting plate, dissolving the
adhesive on a surface contacted with the substrate by the solvent,
and draining the solvent used for dissolving the adhesive from a
first penetrating hole of the supporting plate and a first
penetrating hole of the plate, it is possible to supply the solvent
quickly to the whole surface of the adhesive which bonds the
substrate and the supporting plate so as to strip the supporting
plate in a short period of time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a schematic view showing an embodiment of a
supporting plate according to the present invention;
[0034] FIG. 2 shows the process for forming a supporting plate;
[0035] FIG. 3 is an enlarged view explaining staggered grooves;
[0036] FIG. 4 is an enlarged view explaining honeycomb-shaped
grooves;
[0037] FIG. 5 is a schematic view showing an embodiment of an
apparatus for stripping a supporting plate;
[0038] FIG. 6 is a perspective view of FIG. 5;
[0039] FIG. 7 is a view showing another embodiment of the apparatus
for stripping a supporting plate;
[0040] FIG. 8 is a view explaining a conventional method for
stripping a supporting plate;
[0041] FIG. 9 is a view explaining the conventional method for
stripping a supporting plate, and
[0042] FIG. 10 is a view explaining a drawback of the conventional
art for stripping a supporting plate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] Embodiments of the present invention will be described below
with reference to the attached drawings. FIG. 1 is a schematic view
showing an embodiment of a supporting plate according to the
present invention, and FIG. 2 shows the process for forming a
supporting plate.
[0044] A supporting plate 1 according to the present invention
shown in FIG. 1 is made of a glass plate, a ceramic plate or a
metal plate.
[0045] A circuit-formed surface of a semiconductor wafer W is
bonded to one of the surfaces of the supporting plate 1 by using an
adhesive, which is not shown in the drawing.
[0046] According to the present invention, the supporting plate 1
has a unique structure as described below.
[0047] A first penetrating hole 2 is formed in a substantially
central portion (center) of the supporting plate 1 so as to
penetrate in the thickness direction. A plurality of first
penetrating holes 2 may be formed, and for example, four
penetrating holes 2 are formed in FIG. 1. However, the number of
the penetrating holes 2 is not limited to this.
[0048] Also, grooves 3 connecting with the first penetrating hole 2
are formed on the surface of the supporting plate to which a
semiconductor wafer W is bonded. The grooves 3 are formed so as to
cover almost all the surface up to the outer periphery. As an
example, the grooves 3 have a depth of 0.3 mm in a case where the
supporting plate 1 has a thickness of 0.7 mm. The depth of the
grooves 3 needs to be sufficient so as not to be filled with an
adhesive layer interposed between the supporting plate 1 and the
semiconductor wafer W for bonding. With this, a small gap is
defined between the adhesive layer and the grooves 3, so that a
solvent can quickly flow along the gap when the solvent is supplied
as described below.
[0049] A second penetrating hole 4 is formed in a peripheral
portion of the supporting plate 1. The second penetrating hole 4
penetrates in the thickness direction and connects with the grooves
3 so as to drain a solvent to outside (for withdrawal). It is
possible to provide a plurality of penetrating holes 4 in a
peripheral portion of the supporting plate 1.
[0050] With the above-mentioned structure, the first penetrating
hole 2 to supply a solvent from outside and the second penetrating
hole 4 to discharge a solvent to outside are connected to each
other via the grooves 3.
[0051] The grooves 3 are formed in a grid pattern, part of which is
shown in the enlarged view of FIG. 1. The grooves 3 serve to
connect the first penetrating hole 2 and the second penetrating
hole 4 as mentioned above. Therefore, if a solvent is supplied from
outside to the first penetrating hole 2, the solvent flows from the
central portion to the periphery (outer periphery) portion along
the grooves 3, and reaches the second penetrating hole 4.
[0052] The process for forming the supporting plate 1 provided with
the grooves 3 will be described below with reference to FIG. 2.
[0053] First, a glass plate is prepared, and a dry film resist is
applied to a surface of the plate where the grooves 3 are to be
formed (Step 1).
[0054] An exposure step and a development step are performed to the
dry film resist by using a grid-patterned photo mask (See Steps 2
and 3).
[0055] With these steps, the grid-patterned dry film resist (a
resist mask for forming the grooves 3) is formed on the surface of
the glass plate.
[0056] Next, a protection step is performed to the periphery, and
thereafter, cutting of the glass plate is performed by a
sandblasting method with the grid-patterned dry film resist as a
mask (See Steps 4 and 5).
[0057] With these steps, the grid-patterned grooves 3 are formed on
the surface of the glass plate, which have a predetermined depth
from the surface.
[0058] Next, a dry film resist is applied to the other surface of
the glass plate (See Step 6).
[0059] An exposure step and a development step are performed to the
dry film resist by using a photo mask for forming the first
penetrating hole 2 and the second penetrating hole 4 (See Steps 7
and 8).
[0060] With these steps, the dry film resist corresponding to the
first penetrating hole 2 and the second penetrating hole 4 (a
resist mask for forming the first penetrating hole 2 and the second
penetrating hole 4) is formed on the other surface of the glass
plate.
[0061] Next, a protection step is performed to the periphery (Step
9), and thereafter, cutting of the glass plate is performed by a
sandblasting method with the resist mask for forming the first
penetrating hole 2 and the second penetrating hole 4 (Step 10).
[0062] Next, cleaning is performed to the glass plate (Step 11).
With these steps, the first penetrating hole 2 is formed in the
central portion of the glass plate, which penetrates in the
thickness direction. The second penetrating hole 4 is formed in the
periphery portion, which penetrates in the thickness direction.
[0063] In the process shown in FIG. 2, the grooves 3 are formed
first, and the first penetrating hole 2 and the second penetrating
hole 4 are formed next. However, this order may be reversed.
[0064] A dry etching method or a wet etching method may be used to
form grid-patterned grooves instead of a sandblasting method.
However, when these etching methods are used, it is difficult to
form uniform grooves compared to a sandblasting method although it
depends on the width or the depth of the grooves. A sandblasting
method is preferred to form the grooves 3.
[0065] In the supporting plate 1 of the present embodiment, the
penetrating hole 2 for supplying a solvent from outside is formed
in the central portion of the supporting plate 1 in the thickness
direction, the grid-patterned grooves connecting with the first
penetrating hole 2 are formed on a surface of the supporting plate
to be contacted with an adhesive, and the second penetrating hole 4
for draining a solvent to outside connecting with the grooves 3 is
formed in the peripheral portion of the supporting plate 1 in the
thickness direction. Therefore, when the supporting plate 1 is
stripped from the semiconductor wafer W by using the stripping
apparatus and a stripping method described below, it is possible to
supply a solvent quickly to the whole surface of the adhesive which
bonds the wafer W and the supporting plate 1 so as to strip the
supporting plate 1 in a short period of time compared to the case
of using a conventional supporting plate.
[0066] More specifically, since a conventional supporting plate has
a structure in which a number of penetrating holes are formed in
the thickness direction, dissolution of the adhesive starts in the
area where the adhesive contacts with the penetrating holes.
Therefore, it takes time to distribute the solvent over the
adhesive uniformly.
[0067] In contrast, the supporting plate 1 according to the present
embodiment has a structure in which the grid-patterned grooves 3
are formed on almost all the surface to be contacted with the
adhesive. Therefore, the solvent supplied from the first
penetrating hole 2 flows toward the periphery portion via the
grid-patterned grooves 3 connecting with the first penetrating hole
2, so that the solvent can be distributed quickly over the
adhesive.
[0068] Consequently, it is possible to strip the supporting plate 1
in a short period of time compared to a conventional supporting
plate.
[0069] Further, since a number of penetrating holes are not formed
in the supporting plate 1 according to the present invention,
unlike a conventional supporting plate, when the supporting plate 1
is stripped from the semiconductor wafer W 1 by using the stripping
apparatus and method described below, it is possible to retain the
area where no hole is formed by vacuum attraction. With this, it is
possible to simplify the process for stripping the supporting plate
1 from the semiconductor wafer W.
[0070] Furthermore, since a number of penetrating holes are not
formed in the supporting plate 1 according to the present
invention, unlike a conventional supporting plate, it is possible
to improve the strength of the supporting plate 1, and increase the
reuse rate.
[0071] Also, according to the present invention, since an excessive
amount of force is not exerted on the semiconductor wafer W when
the supporting plate 1 is stripped from the wafer W, there is
little likelihood that cracking or chipping will occur in the wafer
W.
[0072] Consequently, in the semiconductor wafer W to which the
supporting plate 1 is attached, it is possible to utilize the
surface ground by a grinder after thinning the wafer W as a second
circuit-formed surface, for example.
[0073] Next, another embodiment of the supporting plate 1 will be
described below.
[0074] The shape of the grooves 3 is a grid in the above-mentioned
embodiment of the supporting plate 1. However, the shape of the
grooves 3 may be staggered (see the enlarged view of the grooves
shown in FIG. 3(a) and the enlarged view of the periphery shown in
FIG. 3(b)).
[0075] More specifically, the shape of the grooves 3 according to
this embodiment is formed by staggering grid-patterned grooves 3 as
shown in FIG. 1 in columns at a predetermined interval.
[0076] The staggered grooves 3 make it possible to supply the
solvent quickly to the whole surface of the adhesive which bonds
the wafer W and the supporting plate 1 in the same manner as the
case of the grid-patterned grooves 3. Consequently, it is possible
to strip the supporting plate 1 from the substrate in a short
period of time compared to the case of using a conventional
supporting plate.
[0077] Incidentally, the staggered grooves 3 can be formed in the
same process shown in FIG. 2.
[0078] Next, another embodiment of the supporting plate will be
described below.
[0079] The shape of the grooves 3 is honeycombed according to this
embodiment. More specifically, the shape of the grooves 3 is
hexagonal (see the enlarged view of the grooves shown in FIG. 4(a)
and the enlarged view of the periphery shown in FIG. 4(b)).
[0080] In the case where the shape of the grooves 3 is hexagonal,
it is possible to supply the solvent more quickly to the whole
surface of the adhesive which bonds the wafer W and the supporting
plate 1 compared to the cases of the grid-patterned grooves 3 and
the staggered grooves 3. Consequently, it is possible to strip the
supporting plate 1 from the substrate in a shorter period of time
compared to the case of using a conventional supporting plate.
[0081] One of the reasons is that the solvent supplied from the
central portion can more easily reach the peripheral portion
compared to the cases of the grid-patterned grooves 3 and the
staggered grooves 3, by arranging each of the adjacent hexagonal
grooves 3 to be directed from the central portion to the peripheral
portion.
[0082] The hexagonal grooves 3 can be formed in the same processes
shown in FIG. 2.
[0083] As for the shape of the grooves 3, it is also possible to
employ a coil shape in which the grooves are directed from the hole
for supplying a solvent in the center toward the hole for draining
the solvent in the periphery.
[0084] Also, the supporting plate may be comprised of frosted glass
as follows:
[0085] Specifically, the surface of the glass substrate to which
the semiconductor wafer W is attached is roughened by 0.05 mm-0.1
mm, although this is not shown in the drawings. Since the other
features are the same as described above, they are not explained
again.
[0086] In this supporting plate, a solvent supplied from the first
penetrating hole 2 can permeate the whole surface by capillary
action. With this, it is possible to achieve the same function as
the case of the supporting plate provided with the grooves 3
described above.
[0087] Next, an embodiment of the apparatus and the method of
stripping the supporting plate having the above-mentioned structure
from the semiconductor wafer W will be described with reference to
FIGS. 5 and 6.
[0088] In this embodiment, the supporting plate 1 is provided with
the hexagonal grooves 3 shown in FIG. 4, for example.
[0089] The stripping apparatus 20 according to the present
embodiment comprises a plate 10. The plate 1 is supported by an
elevator mechanism so as to be elevated or lowered in the vertical
direction by a predetermined stroke.
[0090] A first penetrating hole 12 (for supplying a solvent from
outside) is formed in the central portion of the plate 10, and a
second penetrating hole 14 (for draining a solvent to outside) is
formed in the periphery portion of the plate 10. Also, a hole 13 is
formed between the first penetrating hole 12 and the second
penetrating hole 14 in the radial direction. The hole 13 is used
for vacuuming, and a recessed portion 15 is formed at the end of
the hole 13 which is in contact with the supporting plate 1. The
first penetrating hole 12 is connected to a solvent supplying
means, for example, by a tube which is not shown in the
drawings.
[0091] When the supporting plate 1 and the semiconductor wafer W
bonded to the supporting plate 1 are attracted to the plate 10
having the above-mentioned structure by vacuum attraction using the
hole 13, the hole for supplying a solvent 12 is coupled to the
first penetrating hole 2 of the supporting plate 1 and the hole for
draining a solvent 14 is coupled to the second penetrating hole 4
of the supporting plate 1. Also, the hole 13 is positioned in an
area of the supporting plate 1 where the first penetrating hole 2
and the second penetrating hole 4 are not formed.
[0092] Next, stripping the supporting plate 1 from the
semiconductor wafer W by using the stripping apparatus 20 will be
described.
[0093] The plate 10 is pushed onto the upper surface of the
supporting plate 1, so that the hole for supplying a solvent 12 of
the plate 10 is aligned (coupled) to the first penetrating hole 2
of the supporting plate 1, and the hole for draining a solvent 14
is aligned (coupled) to the second penetrating hole 4 of the
supporting plate 1 (see FIG. 5).
[0094] A solvent is supplied to the hole for supplying a solvent 12
of the plate 10 by a solvent supplying means (not shown in the
drawing) in this state.
[0095] The solvent flows toward the first penetrating hole 2 of the
supporting plate 1, and reaches the hexagonal grooves 3 which
connect with the penetrating hole 2.
[0096] In this instance, as described above, since the grooves 3
are formed so as to cover almost all surface of the supporting
plate 1 up to the outer periphery, the solvent can be distributed
quickly over an adhesive layer 5 so as to dissolve the adhesive
layer 5.
[0097] The solvent used for dissolving the adhesive layer 5 flows
to the second penetrating hole 4 formed in the periphery of the
supporting plate 1 and connecting with the grooves 3, reaches the
hole for draining a solvent 14 of the plate 10, and is drained to
outside (and withdrawn).
[0098] Next (after a predetermined period of time passes), the
supporting plate 1 is stripped from the semiconductor wafer W.
[0099] In this instance, the pressure inside the recessed portion
15 is reduced by the hole 13 for vacuuming, and the plate 10 is
lifted up in the state where the supporting plate 1 is attracted to
the plate 10 by vacuuming. In this way, the supporting plate 1 is
stripped and the semiconductor wafer W is left to a dicing tape 7.
Incidentally, the dicing tape 7 has adhesiveness and is retained by
a frame 6.
[0100] According to the present embodiment of the stripping
apparatus and the stripping method, the solvent supplied to the
hole for supplying a solvent 12 of the plate 10 flows toward the
first penetrating hole 2 of the supporting plate 1, and reaches the
periphery of the supporting plate 1 via the hexagonal grooves 3
which connect with the penetrating hole 2 of the supporting plate
1. The solvent flows to the hole for draining a solvent 14 of the
plate 10 via the second penetrating hole 4 formed in the periphery
of the supporting plate 1 to be drained to outside.
[0101] As described above, the grooves 3 make it possible to supply
the solvent quickly to the whole surface of the adhesive layer 5.
Consequently, it is possible to strip the supporting plate 1 in a
shorter period of time compared to the case of using the
conventional supporting plate.
[0102] Incidentally, when the supporting plate 1 is stripped from
the semiconductor wafer W, there are cases where the supporting
plate 1 is still attached to the semiconductor wafer W due to
surface tension of the solvent used for dissolving the adhesive
layer 5, which makes it difficult to strip the supporting plate
1.
[0103] In these cases, it is possible to make the supporting plate
1 easier to strip by cancelling (breaking) the surface tension with
air supplied from the solvent supplying hole of the plate 10 to the
first penetrating hole 2 of the supporting plate 1.
[0104] In order to achieve this method, an air supplying means may
be provided in a stripping apparatus having the above-mentioned
structure, and a tube of the air supplying means may be connected
to a tube of the solvent supplying means which leads to the solvent
supplying hole of the plate 10.
[0105] In the above-mentioned embodiments, a solvent is supplied to
the central portion and drained from the periphery portion.
However, it is also possible to supply a solvent to the periphery
portion and drain from the central portion.
[0106] In this instance, the second penetrating hole 4 formed in
the periphery portion of the supporting plate 1 is used for
supplying a solvent from outside, and the first penetrating hole 2
formed in the central portion of the supporting plate 1 is used for
draining the solvent to the outside.
[0107] Also, in the plate 10 of the stripping apparatus 20, the
hole 14 formed in the periphery portion is used for supplying a
solvent from outside, and the hole 12 formed in the central portion
is used for draining the solvent to the outside.
[0108] Since the other features are the same as mentioned above,
they are not explained again.
[0109] It should be noted that the same function can be achieved in
the above-mentioned case as in the case where a solvent is supplied
to the central portion and drained from the periphery portion.
[0110] In the stripping apparatus 20 according to the present
embodiment, the plate 10 is provided in the upper surface of the
supporting plate 1 as shown in FIG. 5. However, the plate 10 may be
provided in the lower surface of the supporting plate 1 as shown in
FIG. 7.
[0111] In this instance, it is not necessary to form the solvent
draining hole 14 although the solvent supplying hole 12 is formed
in the plate 10.
[0112] The present invention is not limited to the above-mentioned
embodiments, and other various structures are possible within the
scope of the present invention.
Effect of the Invention
[0113] According to the present invention, a solvent can be
supplied to the whole surface of the adhesive which bonds the
substrate and the supporting plate so as to strip the supporting
plate in a short period of time and reduce the treatment time.
[0114] Accordingly, it is possible to achieve a supporting plate,
an apparatus and a method for stripping a supporting plate suitable
for reducing the treatment time with high reliability.
* * * * *