U.S. patent application number 10/873158 was filed with the patent office on 2004-11-18 for substrate for semiconductor device, semiconductor chip mounting substrate, semiconductor device and method of fabrication thereof, and circuit board, together with electronic equipment.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Nakayama, Toshinori.
Application Number | 20040227259 10/873158 |
Document ID | / |
Family ID | 26519652 |
Filed Date | 2004-11-18 |
United States Patent
Application |
20040227259 |
Kind Code |
A1 |
Nakayama, Toshinori |
November 18, 2004 |
Substrate for semiconductor device, semiconductor chip mounting
substrate, semiconductor device and method of fabrication thereof,
and circuit board, together with electronic equipment
Abstract
A substrate for semiconductor device which is formed of a
material that can be cut into separate pieces and has mounting
regions for a plurality of semiconductor chips, and at least one
hole is formed therein at a position of intersection between a
plurality of cutting lines for cutting the substrate into a
plurality of individual products.
Inventors: |
Nakayama, Toshinori;
(Sakata-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
26519652 |
Appl. No.: |
10/873158 |
Filed: |
June 23, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10873158 |
Jun 23, 2004 |
|
|
|
09626146 |
Jul 26, 2000 |
|
|
|
6774500 |
|
|
|
|
Current U.S.
Class: |
257/788 ;
257/E23.194 |
Current CPC
Class: |
H01L 2924/01004
20130101; H01L 2224/05599 20130101; H01L 24/48 20130101; H01L
2924/181 20130101; H01L 2224/48465 20130101; H01L 2924/19041
20130101; H01L 2924/01033 20130101; H01L 2224/48227 20130101; H01L
21/481 20130101; H01L 2224/97 20130101; H01L 2224/48091 20130101;
H01L 2924/10253 20130101; H05K 3/284 20130101; H01L 2924/19043
20130101; H01L 2224/73265 20130101; H01L 2924/01005 20130101; H01L
2924/01079 20130101; H01L 2924/3025 20130101; H05K 3/0052 20130101;
H01L 24/73 20130101; H01L 2224/85399 20130101; H01L 2924/00014
20130101; H01L 2224/32225 20130101; H01L 23/562 20130101; H01L
24/97 20130101; H01L 2924/15311 20130101; H01L 2924/01029 20130101;
H05K 2201/09063 20130101; H01L 2224/97 20130101; H01L 2224/85
20130101; H01L 2224/48091 20130101; H01L 2924/00014 20130101; H01L
2224/97 20130101; H01L 2224/83 20130101; H01L 2224/97 20130101;
H01L 2224/73265 20130101; H01L 2224/97 20130101; H01L 2924/15311
20130101; H01L 2224/73265 20130101; H01L 2224/32225 20130101; H01L
2224/48227 20130101; H01L 2924/00 20130101; H01L 2924/15311
20130101; H01L 2224/73265 20130101; H01L 2224/32225 20130101; H01L
2224/48227 20130101; H01L 2924/00 20130101; H01L 2224/97 20130101;
H01L 2924/15311 20130101; H01L 2224/73265 20130101; H01L 2224/32225
20130101; H01L 2224/48227 20130101; H01L 2924/00 20130101; H01L
2224/48465 20130101; H01L 2224/48227 20130101; H01L 2924/00
20130101; H01L 2224/48465 20130101; H01L 2224/48091 20130101; H01L
2924/00 20130101; H01L 2224/73265 20130101; H01L 2224/32225
20130101; H01L 2224/48227 20130101; H01L 2924/00012 20130101; H01L
2924/15311 20130101; H01L 2224/73265 20130101; H01L 2224/32225
20130101; H01L 2224/48227 20130101; H01L 2924/00012 20130101; H01L
2224/97 20130101; H01L 2224/73265 20130101; H01L 2224/32225
20130101; H01L 2224/48227 20130101; H01L 2924/00 20130101; H01L
2924/10253 20130101; H01L 2924/00 20130101; H01L 2924/181 20130101;
H01L 2924/00012 20130101; H01L 2224/85399 20130101; H01L 2924/00014
20130101; H01L 2224/05599 20130101; H01L 2924/00014 20130101; H01L
2924/00014 20130101; H01L 2224/45099 20130101; H01L 2924/00014
20130101; H01L 2224/45015 20130101; H01L 2924/207 20130101 |
Class at
Publication: |
257/788 |
International
Class: |
H01L 023/29 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 28, 1999 |
JP |
11-213184 |
Jun 9, 2000 |
JP |
2000-173294 |
Claims
1-21. (Canceled)
22. A method of fabricating a semiconductor device, the method
comprising: mounting a plurality of semiconductor chips on a
substrate on which is formed at least one hole at a position where
cutting lines intersect, then sealing the plurality of
semiconductor chips with resin; and cutting the substrate and the
resin into individual products along the cutting lines through at
least part of the hole.
23. The method of fabricating a semiconductor device as defined in
claim 22, the resin filling the hole in mounting the plurality of
semiconductor chips.
24. The method of fabricating a semiconductor device as defined in
claim 22, at least one of the holes being formed in the substrate,
a cover being provided to block the hole, before the mounting the
plurality of semiconductor chips, and flow of the resin into the
hole during mounting the plurality of semiconductor chips being
prevented by the cover.
25. The method of fabricating a semiconductor device as defined in
claim 24, further comprising forming an interconnecting pattern in
the substrate, before mounting the plurality of semiconductor
chips, the cover being formed during forming the interconnecting
pattern.
26. The method of fabricating a semiconductor device as defined in
claim 22, one of the holes being formed at the position where the
cutting lines intersect, and the substrate and the resin being cut
through an inner side of the hole in cutting the substrate and the
resin.
27. The method of fabricating a semiconductor device as defined in
claim 22, a plurality of the holes being formed at the position
where the cutting lines intersect, the plurality of holes being
positioned on edges of one of the cutting lines that is to be cut
last, at the position where the cutting lines intersect, and the
substrate and the resin being cut through part of each of the holes
cutting the substrate and the resin.
28. The method of fabricating a semiconductor device as defined in
claim 27, the substrate and the resin being cut by a cutting tool
having a thickness that is greater than the spacing between one of
the holes formed on an edge of the cutting line that is to be cut
last and another of the holes formed on another edge of the cutting
line.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a substrate for a
semiconductor device, a semiconductor chip mounting substrate, a
semiconductor device and method of fabrication thereof, and a
circuit board, together with electronic equipment.
[0003] 2. Description of Related Art
[0004] Methods have been developed for providing small packages
such as chip scale/size packages (CSPs), which involve mounting a
plurality of semiconductor chips on a flexible substrate then
sealing the entire assembly in resin. The resultant sealed product
is then cut into individual packages.
[0005] If the flexible substrate is cut by a blade or router in
this case, a problem occurs in that the cutting generates dust at
the corner portions of individual products, so a better solution is
required.
SUMMARY OF THE INVENTION
[0006] To solve this problem, the present invention provides a
substrate for a semiconductor device, a semiconductor chip mounting
substrate, a semiconductor device and method of fabrication
thereof, and a circuit board, together with electronic equipment
comprising the same, wherein the generation of cutting dust is
reduced.
[0007] (1) According to a first aspect of the present invention,
there is provided a substrate for a semiconductor device, having a
mounting region for a semiconductor chip, wherein at least one hole
is formed at a position where cutting lines intersect.
[0008] The substrate for a semiconductor device in accordance with
this invention can be cut apart to separate it into individual
products that are semiconductor devices. The cutting is done along
cutting lines. In practice, the cutting lines are of a striped form
having a certain width. Corner portions of individual products are
formed at positions where the cutting lines intersect with this
aspect of the invention, "hole" is not limited to a through hole;
it can also refer to any other type of hole that does not
penetrate, such as a depression. If a hole is formed at each
position where cutting lines intersect, part of the substrate for
the semiconductor device forms an indented shape at each corner
portion of each individual product. If a depression is formed at
each position where cutting lines intersect, part of the substrate
for the semiconductor device is made thinner at each corner portion
of each individual product.
[0009] Since parts of the substrate for the semiconductor device
are either indented inward or is thinner at the corner portions of
the individual products, it is therefore possible to reduce the
amount of cutting dust when the cutting is done.
[0010] (2) In this substrate for a semiconductor device, one of the
holes may be formed at the position where the cutting lines
intersect; and the hole may be formed to a size that comprises an
intersection portion of the cutting lines.
[0011] This ensures that the corner portions of individual products
are defined by inner wall surfaces of the holes or thinner portions
formed by the provision of the depressions. Part of the substrate
for the semiconductor device is formed to be indented inward or
thinner at each corner portion of each individual product.
[0012] (3) In this substrate for a semiconductor device, a
plurality of the holes may be formed at the position where the
cutting lines intersect; and part of each of the holes may be
superimposed on an intersection portion between the cutting
lines.
[0013] This ensures that the corner portions of individual products
are defined by inner wall surfaces of the holes or thinner portions
formed by the provision of the depressions. Part of the substrate
for the semiconductor device can be formed to be indented inward or
thinner at each corner portion of each individual product.
[0014] Moreover, since it is sufficient that part of each hole is
superimposed on the intersection portion between the cutting lines,
each hole can be made smaller.
[0015] (4) In this substrate for a semiconductor device, the
plurality of holes may be positioned on edges of one of the cutting
lines that is to be cut last, in the intersection portion.
[0016] (5) In this substrate for a semiconductor device, the
plurality of holes may be formed on part of the cutting line that
is to be cut last, when that part is to be cut earlier than the
intersection portion between the cutting lines.
[0017] (6) In this substrate for a semiconductor device, the
plurality of holes may be formed on part of the cutting line that
is to be cut last, when that part is to be cut after the
intersection portion between the cutting lines.
[0018] (7) In this substrate for a semiconductor device, the
spacing between one of the holes formed on an edge of the cutting
line that is to be cut last and another of the holes formed on
another edge of the cutting line may be less than the thickness of
a cutting portion of a cutting tool.
[0019] This configuration ensures that the cutting can be done to
cut away a part of each hole and that the corner portions of
individual products can be defined by inner wall surfaces of the
holes or thinner portions formed by provision of the
depressions.
[0020] (8) In this substrate for a semiconductor device, at least
one of the holes may be formed; and the hole may have an aperture
portion that is closed by a cover.
[0021] This makes it possible to prevent the sealing resin from
flowing into the hole, and thus prevent the sealing resin from
seeping from one surface of the semiconductor device to the other
surface thereof through the hole.
[0022] (9) In this substrate for a semiconductor device, an
interconnecting pattern may be formed; and the cover may be formed
of the same material as the interconnecting pattern.
[0023] This makes it possible to form the cover without increasing
the steps of the fabrication process.
[0024] (10) According to a second aspect of the present invention,
there is provided a semiconductor chip mounting substrate,
comprising: a substrate of a material that can be cut into separate
pieces, in which is formed at least one hole at an intersection
portion between cutting lines for separating the substrate into a
plurality of individual products; and a plurality of semiconductor
chips which are mounted on the substrate.
[0025] The substrate in accordance with this aspect of the
invention, on which is mounted a plurality of semiconductor chips,
can be cut apart to form a plurality of individual products. The
cutting is done along the cutting lines. In practice, the cutting
lines are of a striped form having a certain width. Corner portions
of individual products of the substrate are formed at positions
where the cutting lines intersect.
[0026] With this aspect of the invention, "hole" is not limited to
a through hole; it can also refer to any other type of hole that
does not penetrate, such as a depression. If a hole is formed at
each position where cutting lines intersect, each corner portion of
each individual product of the substrate forms an indented shape.
If a depression is formed at each position where cutting lines
intersect, each corner portion of each individual product of the
substrate is made thinner.
[0027] Since the corner portions of individual pieces of the
substrate are either indented inward or are thinner, it is possible
to reduce the amount of cutting dust even when the cutting is done
along the intersecting cutting lines.
[0028] (11) In this semiconductor chip mounting substrate, the
plurality of semiconductor chips may be sealed in by resin.
[0029] This configuration makes it possible to cut the resin apart
simultaneously with the cutting of the substrate.
[0030] (12) In this semiconductor chip mounting substrate, the
resin may fill the hole.
[0031] This provides resin in the intersection portion between
cutting lines. If holes are formed in the substrate, each corner
portion of the individual pieces of substrate and resin is formed
by resin. If depressions are formed in the substrate, each corner
portion of the individual pieces of substrate and resin is formed
by a thinner piece of substrate and the resin.
[0032] (13) In this semiconductor chip mounting substrate, the hole
may be formed to a size that comprises the intersection portion of
the cutting lines.
[0033] (14) In this semiconductor chip mounting substrate, the hole
may have an aperture portion that is closed by a cover, and the
resin may be provided over a surface of the substrate for a
semiconductor device where the cover is provided.
[0034] This makes it possible to prevent the resin from flowing
into the hole and thus prevent seepage of the resin from one
surface of the substrate to the other surface thereof through the
hole.
[0035] (15) According to a third aspect of the present invention,
there is provided a semiconductor device comprising:
[0036] a semiconductor chip;
[0037] a substrate on which the semiconductor chip is mounted and
which is formed by cutting apart a larger substrate; and
[0038] resin for sealing the semiconductor chip;
[0039] wherein the semiconductor device has an outer shape having a
corner portion; and
[0040] wherein apart of the substrate is indented further inward
than an edge surface of the resin at the corner portion.
[0041] This aspect of the invention provides a configuration that
reduces the amount of cutting dust that remains on the substrate
after being generated at the corner portions by the cutting apart
of the substrate.
[0042] (16) In this semiconductor device, the substrate at the
corner portion may form a shape that is indented in the opposite
direction from the direction in which the corner portion protrudes,
and thus an edge surface of the substrate may be indented further
inward than the edge surface of the resin.
[0043] (17) In this semiconductor device, the formation of a
thinner portion in the substrate at the corner portion may ensure
that a surface of the thinner portion of the substrate is indented
further inward than the edge surface of the resin.
[0044] (18) In this semiconductor device, the part of the substrate
that is indented further inward than the edge portion of the resin
at the corner portion may be covered by the resin.
[0045] This ensures that part of the substrate is covered by resin
at the corner portion so that no cutting dust is generated by the
cutting apart of the substrate.
[0046] (19) In this semiconductor device, a cover may be provided
at the corner portion, between the substrate and the resin; and the
part of the substrate that is indented further inward than the edge
surface of the resin may be exposed.
[0047] (20) According to a fourth aspect of the present invention,
there is provided a circuit board which has any of the previously
described semiconductor devices mounted thereon.
[0048] (21) According to a fifth aspect of the present invention,
there is provided electronic equipment which is provided with any
of the previously described semiconductor devices.
[0049] (22) According to a sixth aspect of the present invention,
there is provided a method of fabricating a semiconductor device,
the method comprising:
[0050] a first step of mounting a plurality of semiconductor chips
on a substrate on which is formed at least one hole at a position
where cutting lines intersect, then sealing the plurality of
semiconductor chips with resin; and
[0051] a second step of cutting the substrate and the resin into
individual products along the cutting lines, through at least part
of the hole.
[0052] With this aspect of the invention, the substrate on which a
plurality of semiconductor chips is mounted is cut apart to form a
plurality of individual products. The cutting is done along cutting
lines. In practice, the cutting lines are of a striped form having
a certain width. Corner portions of individual pieces of the
substrate and resin are formed at positions where the cutting lines
intersect.
[0053] With this aspect of the invention, "hole" is not limited to
a through hole; it can also refer to any other type of hole that
does not penetrate, such as a depression. If a hole is formed at
each position where cutting lines intersect, part of the substrate
for the semiconductor device forms an indented shape at each corner
portion of each individual piece of the substrate and resin. If a
depression is formed at each position where cutting lines
intersect, part of the substrate for the semiconductor device is
made thinner at each corner portion of each individual piece of the
substrate and resin.
[0054] Since the part of the substrate is either indented inward or
is thinner at each corner portion of each individual piece of the
substrate and resin, it is possible to reduce the amount of cutting
dust when the cutting is done along the intersecting cutting
lines.
[0055] (23) In this method of fabricating a semiconductor device,
the resin may fill the hole in the first step.
[0056] This ensures that resin is provided at the each intersection
portion of the cutting lines. If holes are formed in the substrate,
each corner portion of the individual pieces of the substrate and
resin is formed by resin. If depressions are formed in the
substrate, each corner portion of the individual pieces of the
substrate and resin is formed by a thinner piece of the substrate
and resin.
[0057] (24) In this method of fabricating a semiconductor device,
at least one of the holes may be formed in the substrate; a cover
may be provided to block the hole, before the first step; and flow
of the resin into the hole during the first step may be prevented
by the cover.
[0058] This makes it possible to prevent the resin from flowing
into the hole and thus prevent seepage of the resin from one
surface of the substrate to the other surface thereof through the
hole.
[0059] (25) The method of fabricating a semiconductor device may
further comprise a step of forming an interconnecting pattern in
the substrate, before the first step, and the cover may be formed
during the step of forming the interconnecting pattern.
[0060] This makes it possible to provide a cover without increasing
the number of fabrication steps.
[0061] (26) In this method of fabricating a semiconductor device,
one of the holes may be formed at the position where the cutting
lines intersect; and the substrate and the resin may be cut through
an inner side of the hole in the second step.
[0062] This makes it possible to define the corner portions of
individual pieces of the substrate with inner wall surfaces of the
holes or thinner portions formed by the provision of the
depressions.
[0063] (27) In this method of fabricating a semiconductor device, a
plurality of the holes may be formed at the position where the
cutting lines intersect; the plurality of holes may be formed to be
positioned on edges of one of the cutting lines that is to be cut
last, at the position where the cutting lines intersect; and the
substrate and the resin may be cut through part of the respective
holes in the second step.
[0064] This makes it possible to define the corner portions of
individual products of the substrate with inner wall surfaces of
the holes or thinner portions formed by the provision of the
depressions. Moreover, since it is sufficient that part of each
hole is superimposed on the intersection portion between the
cutting lines, each hole can be made smaller.
[0065] (28) In this method of fabricating a semiconductor device,
the substrate and the resin may be cut by a cutting tool having a
thickness that is greater than the spacing between one of the holes
formed on an edge of the cutting line that is to be cut last and
another of the holes formed on another edge of the cutting
line.
[0066] This configuration ensures that the cutting is done to cut
away part of each hole and that the corner portions of individual
products of the substrate are defined with inner wall surfaces of
the holes or thinner portions formed by provision of the
depressions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] FIG. 1 shows a substrate for a semiconductor device in
accordance with a first embodiment to which this invention is
applied;
[0068] FIG. 2 shows a method of fabricating a semiconductor device
in accordance with the first embodiment to which this invention is
applied;
[0069] FIG. 3 shows more the method of fabricating a semiconductor
device in accordance with the first embodiment to which this
invention is applied;
[0070] FIGS. 4A and 4B show still more of the method of fabricating
a semiconductor device in accordance with the first embodiment to
which this invention is applied;
[0071] FIG. 5 shows even more of the method of fabricating a
semiconductor device in accordance with the first embodiment to
which this invention is applied;
[0072] FIG. 6 shows yet more of the method of fabricating a
semiconductor device in accordance with the first embodiment to
which this invention is applied;
[0073] FIG. 7 shows a semiconductor device in accordance with the
first embodiment to which this invention is applied;
[0074] FIG. 8 is another view of the semiconductor device in
accordance with the first embodiment to which this invention is
applied;
[0075] FIG. 9 shows a substrate for a semiconductor device in
accordance with a second embodiment to which this invention is
applied;
[0076] FIG. 10 shows a method of fabricating a semiconductor device
in accordance with the second embodiment to which this invention is
applied;
[0077] FIGS. 11A and 11B show a modification of the substrate for a
semiconductor device in accordance with the second embodiment to
which this invention is applied;
[0078] FIG. 12 shows a semiconductor device in accordance with a
third embodiment to which this invention is applied;
[0079] FIG. 13 shows a semiconductor device in accordance with a
fourth embodiment to which this invention is applied; and
[0080] FIG. 14 shows electronic equipment that is provided with a
semiconductor device fabricated by applying the method in
accordance with this invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0081] Embodiments of the present invention are described below
with reference to the accompanying drawings.
[0082] First Embodiment
[0083] A substrate for a semiconductor device in accordance with a
first embodiment to which this invention is applied is shown in
FIG. 1. After a plurality of semiconductor chips 20 has been
mounted on a substrate for a semiconductor device (hereinafter
called "substrate") 10, as shown in FIG. 2, the assembly is cut
into a plurality of individual products to form a plurality of
semiconductor devices 30 (see FIG. 8). The substrate 10 becomes an
interposer for the semiconductor devices when they are
separated.
[0084] The substrate 10 is formed from a material that can be cut
into separate pieces. The present invention is particularly
effective when corner portions are formed by the cutting, and when
the substrate 10 has been formed of a material that readily
generates cutting dust at those corner portions. It is preferable
to apply the present invention when the substrate 10 is formed of a
material that is elastic, by way of example. The material of the
substrate 10 could be any of various inorganic materials or
materials including inorganic substance, but it is preferable to
use an organic material therefor. An example of the substrate 10
formed from an organic material is a flexible substrate consisting
of a polyimide resin.
[0085] At least one mounting region 12 is provided on the substrate
10, for mounting the plurality of semiconductor chips 20 (a
plurality of mounting regions 12 is shown in FIG. 1, but it could
equally well be one). An interconnecting pattern 13 (see FIG. 8)
could also be formed in at least one surface of each mounting
region 12 (in most cases, only one surface is used therefor, but
both surfaces could also be used). A plurality of through holes 14
could be formed in the substrate 10, to enable electrical contact
between one surface and the other surface. The plurality of through
holes 14 could be formed in each mounting region 12. Inner wall
surfaces of the through holes 14 could be plated with a conductive
material such as copper or gold, or the through holes 14 could be
filled with a conductive material. A component such as a solder
ball to form an external terminal could be formed on top of each of
the through holes 14.
[0086] At least one hole 16 is formed in the substrate 10, separate
from the through holes 14. More specifically, at least one hole 16
is formed at each position where cutting lines L intersect (there
is only one hole for each intersection in FIG. 1). The shape of
this hole 16 is not limited; it could be a round hole or a square
hole. The size of the hole 16 (its diameter if it is a round hole)
is greater than the width of the cutting lines L, in other words,
the thickness of the blade of a cutting tool. If the thickness of
the blade of the cutting tool is 100 .mu.m to 300 .mu.m (generally
100 .mu.m to 200 .mu.m, but preferably on the order of 150 .mu.m),
by way of example, it is preferable that the diameter of the hole
16 is 150 .mu.m to 500 .mu.m, taking into account positioning
errors of the cutting lines L of 50 .mu.m to 200 .mu.m.
[0087] The cutting lines L indicate positions where the substrate
10 is to be severed and are set at positions that delimit the
plurality of individual products to be obtained from the substrate
10. In the example shown in FIG. 1, the plurality of cutting lines
L is divided into a first group consisting of a plurality of
parallel cutting lines L and a second group of a plurality of
cutting lines L that extend perpendicular to the cutting lines L of
the first group.
[0088] Since the cutting lines L indicate regions of the substrate
10 that will be separated while being cut at a predetermined width,
they form stripes of a predetermined width in practice. The cutting
lines L have a width that is the thickness of the blade of the
cutting tool. Therefore, each intersection portion 18 between the
cutting lines L is actually a region having a predetermined area,
not a point.
[0089] Each hole 16 is formed to a size that comprises the
corresponding intersection portion 18 between a plurality of
cutting lines L therein, in other words, is formed to be larger
than the intersection portion 18. If each intersection portion 18
is positioned completely within the corresponding hole 16, the
corner portions of individual pieces of the substrate 10 are not
defined by the intersection portions 18. The corner portions of
each individual piece of the substrate 10 are defined by the inner
wall surfaces of the corresponding holes 16. When the substrate 10
is cut into a plurality of individual products, therefore, no
cutting dust is generated at the corner portions of the individual
products.
[0090] With this embodiment of the invention, the peripheral edge
portions of the substrate 10 are cut away, then the plurality of
individual products is formed from the interior region. If it does
not matter whether cutting dust is generated at the peripheral edge
portions that are to be discarded, part of each relevant
intersection portion 18 could protrude from the corresponding hole
16 in the direction of that peripheral edge portion. In such a
case, the corner portions of the individual pieces of the substrate
10 are defined by the inner wall surfaces of the holes 16, as
described above, but the corner portions of the peripheral edge
portions that are to be discarded are formed by intersecting cut
and thus it is inevitable that cutting dust will be generated.
[0091] The substrate for a semiconductor device in accordance with
this embodiment has the above configuration and a semiconductor
device using this substrate is fabricated by the method described
below. The method of fabricating a semiconductor device comprises a
semiconductor chip mounting substrate fabrication process (first
step) and a semiconductor chip mounting substrate cutting process
(second step).
[0092] Semiconductor Chip Mounting Substrate Fabrication
Process
[0093] The process of fabricating the semiconductor chip mounting
substrate is shown in FIGS. 2 to 4A. A plurality of semiconductor
chips 20 will be mounted on the substrate 10, each in one of the
plurality of mounting regions 12, as shown in FIG. 2. In this
embodiment of the invention, the semiconductor chips 20 will be
bonded so that the terminals thereof turn upward (face-up bonding).
The semiconductor chips 20 could be bonded to the substrate 10 by
an adhesive 21 or the like. The interconnecting pattern 13 (see
FIG. 8) is formed on the substrate 10. The semiconductor chips 20
could be mounted on the surface on which the interconnecting
pattern 13 is formed, and a plurality of external terminals 26
could be formed on the surface on the opposite side, via the
through holes 14, by a process that will be described later.
[0094] The semiconductor chips 20 and the interconnecting pattern
13 are then connected electrically. In FIG. 3, they are shown
connected together by wires 22, by way of example. Alternatively,
the semiconductor chips 20 could be mounted on the substrate 10 by
face-down bonding, in contrast to the orientation of this
embodiment. In such a case, the electrical connections could be
done by using an anisotropic conductive material, solder,
conductive paste, or the like, or ultrasonic waves could be used to
apply a metal bond. Heat or pressure could be added to the
ultrasonic waves.
[0095] The plurality of semiconductor chips 20 is then sealed in
with resin 24 (by batch sealing, for example), as shown in FIG. 4A.
The entire substrate 10 could be sealed in by the resin 24. A metal
die could be used for this sealing, in which case the resin 24
could be called molding resin. Alternatively, the resin 24 could be
provided on top of the substrate 10 then spread evenly by a
squeegee, or by potting. The surface of the resin 24 provided on
top of the substrate 10 could be either flat or uneven. In a
variant shown in FIG. 4B by way of example, grooves 126 could be
formed in resin 124. If the grooves 126 are formed along the
cutting lines L, this would facilitate the positioning for the
cutting.
[0096] If the interconnecting pattern 13 is formed on the surface
of the substrate 10 on which the semiconductor chips 20 are
mounted, the interconnecting pattern 13 is covered and protected by
the resin 24. The resin 24 could also fill all the holes 16 formed
in the substrate 10.
[0097] The semiconductor chip mounting substrate shown in FIG. 4A
is obtained by the above steps. The semiconductor chip mounting
substrate is an intermediate product in the fabrication of a
plurality of semiconductor devices, with the plurality of
semiconductor chips 20 incorporated therein. The plurality of
semiconductor chips 20 are sealed in by the resin 24. Details of
the substrate 10 of the semiconductor chip mounting substrate are
as described previously. The holes 16 of the substrate 10 could be
filled with the resin 24.
[0098] Before the semiconductor chip mounting substrate is cut
apart, a plurality of external terminals 26 could be provided
thereon, as shown in FIG. 5. At this point, it is possible to
provide the external terminals 26 simultaneously for a plurality of
semiconductor devices. The external terminals 26 could be solder
balls. The external terminals 26 could be provided on land portions
formed on the substrate 10. If the interconnecting pattern 13 is
formed on the surface on which the resin 24 is provided, electrical
connection between the external terminals 26 and the
interconnecting pattern 13 can be obtained either by solder or
other conductive material that is provided within the through holes
14 or by the through holes 14 having inner surfaces plated with
copper or other conductive material.
[0099] Semiconductor Chip Mounting Substrate Cutting Process
[0100] The semiconductor chip mounting substrate comprising the
substrate 10, the plurality of semiconductor chips 20, and the
resin 24 is then cut into separate products, as shown in FIG. 6. A
cutting tool such as a blade 28 that is used for slicing silicon
wafers could be used for this cutting into separate products. The
cutting tool, such as the blade 28, is moved relative to the
substrate 10 to cut apart the substrate 10. Either the blade 28
could be moved or the substrate 10 could be moved. The positions of
the cutting is on the cutting lines L shown in FIG. 1. In other
words, the substrate 10 and the resin 24 are cut apart through the
inner sides of the holes 16, to obtain semiconductor devices 30
that are individual products. If the resin 24 has filled the holes
16, corner portions 32 are formed for each semiconductor device 30
by the resin 24 (see FIG. 7). There is therefore no generation of
cutting dust from the substrate 10.
[0101] A cross section of the substrate 10 and the resin 24 is
shown in FIG. 7. In the example shown in FIG. 7, part of the
substrate 10 is indented further inward than the edge surface of
the resin 24 at the corner portion 32 of the semiconductor device
30. As mentioned previously, each intersection portion 18 between
cutting lines L is positioned within one of the holes 16 of the
substrate 10, so that the corner portions of the substrate 10 are
defined by inner wall surfaces of the holes 16. The inner wall
surface of each of the holes 16 of the substrate 10 therefore forms
a shape that is indented in the opposite direction to the direction
in which the corner portion 32 protrudes, at the corner portion 32
of each semiconductor device 30. Since the resin 24 fills the holes
16 in the substrate 10 during the process of fabricating the
semiconductor chip mounting substrate, the inner wall surfaces of
the holes 16 are covered with the resin 24.
[0102] The semiconductor device 30 in accordance with this
embodiment of the invention is shown in FIG. 8. This semiconductor
device 30 comprises the semiconductor chip 20, an individual piece
of the substrate 10 on which the semiconductor chip 20 was mounted
and which was formed by cutting a larger substrate apart, and an
individual piece of the resin 24 which seals the semiconductor chip
20 and which was formed by cutting a larger piece of resin apart.
All other characteristics of this embodiment are as previously
described.
[0103] The semiconductor device 30 of FIG. 8 is mounted on a
circuit board 34. In general, this circuit board 34 would have an
organic substrate, such as a glass epoxy substrate by way of
example. An interconnecting pattern 36 is then formed on the
circuit board 34 of a material such as copper, to create desired
circuitry, and this wiring pattern 36 and the external terminals 26
of the semiconductor device 30 are connected together to make them
electrically conductive.
[0104] Second Embodiment
[0105] A substrate for a semiconductor device in accordance with a
second embodiment to which this invention is applied is shown in
FIG. 9. A plurality of holes 46 is formed in a substrate for a
semiconductor device (hereinafter called "substrate") 40, as shown
in FIG. 9. The substrate 40 could have the same configuration as
the substrate 10 of FIG. 1, apart from the holes 16.
[0106] In this embodiment of the invention a plurality of holes 46
are formed at positions where the pluralities of cutting lines
L.sub.1 and L.sub.2 intersect. The cutting lines L.sub.1 and the
cutting lines L.sub.2 intersect at right angles. The cutting lines
L.sub.1 and L.sub.2 are the same as the cutting lines L of the
first embodiment. Therefore, the cutting lines L.sub.1 and L.sub.2
form stripes of a predetermined width, as shown in FIG. 10. Part of
the respective hole 46 overlap an intersection portion 48 between
the cutting lines L.sub.1 and L.sub.2.
[0107] In this embodiment of the invention, a plurality of the
holes 46 is formed to be positioned on the edges of the cutting
line L.sub.1 or the cutting line L.sub.2. In addition, corner
portions of the intersection portions 48 of the cutting lines
L.sub.1 and L.sub.2 overlap the corresponding holes 46.
[0108] The spacing D between each pair of the holes 46 that are
positioned on the edges of the cutting lines L.sub.1 or L.sub.2 is
preferably less than the width of the cutting lines L.sub.1 and
L.sub.2, in other words, less than the thickness of the cutting
tool (for example, the blade 28), as shown in the enlargement of
FIG. 9. If the thickness of the blade of the cutting tool is 100
.mu.m to 300 .mu.m (generally 100 .mu.m to 200 .mu.m, but
preferably on the order of 150 .mu.m), by way of example, the
spacing D is preferably less than that. The diameter of the holes
46 is sufficient to allow for positioning error in the cutting
lines L.sub.1 and L.sub.2, that is on the order of 50 .mu.m to 200
.mu.m, for example. With this embodiment of the invention, the
diameter of the holes 46 can be made smaller than in the first
embodiment. As a result, it is possible to reduce a state in which
the resin incorporated into the holes 46 is forced out onto the
surface of the substrate 40.
[0109] With this embodiment of the invention, the cutting of the
plurality of intersecting cutting lines L.sub.1 and L.sub.2 is done
first along the cutting lines L.sub.1, and subsequently (finally)
along the cutting lines L.sub.2. The cutting that is done last
generates cutting dust at the corner portions of individual parts
of the substrate 40, so it is preferable that the hole 146 of FIG.
10 is positioned at at least a corner portion of an individual
product. When the plurality of individual products is to be formed
from all other regions excluding the peripheral edge portions of
the substrate 40, it is not always necessary to have holes 246,
346, and 466 that are positioned at the corner portions within the
excluded peripheral edge portions.
[0110] Similarly, the holes 46 are sufficient to be positioned on
the edges of the cutting line L.sub.2 for the final cutting, when
the corner portions of a plurality of individual products are to be
formed by the plurality of intersecting cutting lines L.sub.1 and
L.sub.2.
[0111] A modification of this embodiment of the invention is shown
in FIGS. 11A and 11B, with the cutting being performed along the
cutting line L.sub.2 from the top of each diagram to the
bottom.
[0112] If cutting dust is to be generated at part of the cutting
line L.sub.2 that is cut by the final cutting and that part is cut
earlier than the intersection portion 48, the holes 46 are formed
as shown in FIG. 11A. In other words, the holes 46 could be formed
on the cutting line L.sub.2 only at the part that is cut earlier
than the intersection portion 48. In that case, it is originally
difficult for cutting dust to occur at another part of the cutting
line L.sub.2 that is cut after the intersection portion 48.
[0113] Alternatively, if cutting dust is to be generated at part of
the cutting line L.sub.2 that is cut by the final cutting and that
part is cut after the intersection portion 48, the holes 46 are
formed as shown in FIG. 11B. In other words, the holes 46 could be
formed on the cutting line L.sub.2 only at the part that is cut
after the intersection portion 48. In that case, it is originally
difficult for cutting dust to occur at another part of the cutting
line L.sub.2 that is cut earlier than the intersection portion
48.
[0114] The conditions that determine on which part of the cutting
line cutting dust is most likely to occur depend on the properties
of the substrate 40 and the resin and the cutting method (such as
the direction of rotation or direction of movement of the cutting
tool and the surface of the substrate 40 that is touched by the
cutting tool).
[0115] This embodiment of the invention has the configuration
described above and details that were described with reference to
the first embodiment can also be applied as far as possible
thereto. In addition, details that were described with reference to
the first embodiment can also be applied to a semiconductor chip
mounting substrate that uses the substrate 40 in accordance with
this embodiment of the invention, allowing for differences in the
configuration of the substrate 40.
[0116] The method of fabricating a semiconductor device that uses
the substrate 40 in accordance with this embodiment of the
invention involves cutting the substrate 40 and the resin through
part of each of the holes 46. A cutting tool that is thicker than
the spacing D between each pair of holes 46 is used during the
cutting step to cut through the substrate 40 and the resin. All
other details that were described with reference to the first
embodiment can be applied to this embodiment.
[0117] Third Embodiment
[0118] A semiconductor device in accordance with a third embodiment
to which this invention is applied is shown in FIG. 12. The
semiconductor device of FIG. 12 comprises a substrate 50 that has
formed individual products and resin 52 that seals a plurality of
semiconductor chips that were mounted on the substrate 50. A
thinner portion 56 is formed in the substrate 50 at each of corner
portions 54 of the semiconductor device. The thinner portion 56 is
formed as a depression in at least one of the upper and lower
surfaces of the substrate 50. The thickness of the thinner portion
56 is preferably between approximately 1/3 and 1/4 of the thickness
of the substrate 50, by way of example. The size of the thinner
portion 56 (or the diameter thereof, if circular) is preferably
greater than the thickness of the cutting tool (when viewed from a
direction perpendicular to the substrate 50). If the depression is
placed facing into the resin 52, as shown in FIG. 12, the resin 52
could cover that depression. Alternatively, the depression could be
on the opposite side from the resin 52. The formation of the
thinner portion 56 ensures that the depression of the substrate 50
is indented further inward than the edge surfaces of the resin
52.
[0119] The individual pieces of the substrate 50 that are used by
the semiconductor devices in accordance with this embodiment can be
formed from substrates for semiconductor devices having mounting
regions for a plurality of semiconductor chips. More specifically,
the holes 16 or 46 of the substrate 10 or 40 of the first or second
embodiment could be converted into depressions to give a structure
that can be used as a substrate for semiconductor devices. In that
case, the depressions are cut to form the previously described
thinner portions 56.
[0120] Since depressions are formed instead of holes in the
substrate for a semiconductor device in accordance with this
embodiment of the invention, there is no seepage of resin to the
opposite side when resin is provided. This substrate for a
semiconductor device could be used to fabrication a semiconductor
chip mounting substrate. Semiconductor devices could be fabricated
by cutting apart this semiconductor chip mounting substrate. The
methods described above with reference to the previous embodiments
can be applied thereto. Since the cutting is done through the
depressions instead of holes, the cutting ends at portions that
have become thinner, so there is little cutting dust.
[0121] Chemical half-etching could be used when forming the
depressions of this substrate for semiconductor devices. In such a
case, the depressions could be formed on either the surface
provided with the resin or on the opposite side thereto.
Alternatively, a substrate for a semiconductor device could be used
to fabricate a conductor chip mounting substrate, then depressions
are formed in a substrate for a semiconductor device that forms one
part thereof. In such a case, the depressions are formed on the
opposite side from the surface on which the resin has already been
provided.
[0122] Fourth Embodiment
[0123] A semiconductor device in accordance with a fourth
embodiment of this invention will now be described, with reference
to FIG. 13. The semiconductor device in accordance with this
embodiment has the configuration of the semiconductor device
described with reference to the first or second embodiment, but
with the addition of a cover (or seal member, or shielding member)
66.
[0124] In other words, the cover 66 is provided between a substrate
60 and resin 62 at each corner portion 64 of the semiconductor
device. An edge surface 68 that is formed to be indented in the
opposite direction to the direction of protrusion of the corner
portion 64 is exposed at the corner portion 64. The edge surface 68
is indented further inward than the edge surfaces of the resin 62.
Note that a material such as a resin could be provided to cover the
edge surface 68.
[0125] The semiconductor device in accordance with this embodiment
of the invention could be configured by using a substrate for a
semiconductor device wherein the aperture portion of each of the
holes 16 or 46 of the substrate 10 or 40 of the first or second
embodiment could be closed off by the cover 66. The material of the
cover 66 could be a resin or a metal such as copper. The cover 66
could be formed of the same material as the interconnecting pattern
(a conductive material such as copper), at the same time that the
interconnecting pattern is formed on the substrate for the
semiconductor device. If the cover 66 is made at the same time as
the interconnecting pattern, there is no need to increase the
number of fabrication steps. Alternatively, the cover 66 could be
provided on the surface on the opposite side from the
interconnecting pattern. Further alternatively, a liquid coating
material could be poured into the holes 16 or 46 then solidified.
Note if that the color of the cover 66 is different from the color
of the substrate for the semiconductor device, the color of the
cover 66 will be visible through the holes 16 or 46. In other
words, the holes 16 or 46 can be identified by the color of the
cover 66. Since the holes 16 or 46 are aligned along the cutting
lines L, L.sub.1, and L.sub.2, this can be used to mark the
cutting.
[0126] If the substrate for a semiconductor device in accordance
with this embodiment is used and resin is provided over the surface
on which the covers 66 are provided, the resin will not flow from
the holes 16 or 46 and thus there will be no seepage to the
opposite side.
[0127] All other details that were described with reference to the
first and second embodiments can be applied to this embodiment.
[0128] A notebook-sized personal computer 100 having a
semiconductor device to which this invention is applied is shown in
FIG. 14.
[0129] Note that the "semiconductor chip" that is a structural
component of the present invention could be replaced by an
"electronic element," and electronic elements (either active
elements or passive elements) can be mounted on a substrate to
fabricate an electronic component, in a manner similar to that of
semiconductor chips. Examples of electronic components fabricated
by using such electronic elements include optical elements,
resistors, capacitors, coils, oscillators, filters, temperature
sensors, thermistors, varistors, variable resistors, or fuses, by
way of example.
* * * * *