U.S. patent application number 10/207086 was filed with the patent office on 2003-03-27 for surface package type semiconductor package and method of producing semiconductor memory.
Invention is credited to Kitamura, Wahei, Murakami, Gen, Nishi, Kunihiko.
Application Number | 20030057113 10/207086 |
Document ID | / |
Family ID | 26515558 |
Filed Date | 2003-03-27 |
United States Patent
Application |
20030057113 |
Kind Code |
A1 |
Kitamura, Wahei ; et
al. |
March 27, 2003 |
Surface package type semiconductor package and method of producing
semiconductor memory
Abstract
In surface packaging of thin resin packages such as resin molded
memory ICs or the like, cracks of the package occur frequently at a
solder reflow step where thermal impact is applied to the package
because the resin has absorbed moisture before packaging. To solve
this problem, the devices are packaged moisture-tight at an
assembly step of the resin molded devices where the resin is still
dry, and are taken out from the bags immediately before the
execution of surface packaging.
Inventors: |
Kitamura, Wahei; (Tokyo,
JP) ; Murakami, Gen; (Tokyo, JP) ; Nishi,
Kunihiko; (Tokyo, JP) |
Correspondence
Address: |
ANTONELLI TERRY STOUT AND KRAUS
SUITE 1800
1300 NORTH SEVENTEENTH STREET
ARLINGTON
VA
22209
|
Family ID: |
26515558 |
Appl. No.: |
10/207086 |
Filed: |
July 30, 2002 |
Related U.S. Patent Documents
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Application
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10207086 |
Jul 30, 2002 |
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09843937 |
Apr 30, 2001 |
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6443298 |
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09843937 |
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09387049 |
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6223893 |
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09387049 |
Aug 31, 1999 |
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09094490 |
Jun 10, 1998 |
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5988368 |
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09094490 |
Jun 10, 1998 |
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08712559 |
Sep 13, 1996 |
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5803246 |
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08712559 |
Sep 13, 1996 |
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08264745 |
Jun 23, 1994 |
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5607059 |
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08264745 |
Jun 23, 1994 |
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07791539 |
Nov 14, 1991 |
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07791539 |
Nov 14, 1991 |
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07392029 |
Aug 10, 1989 |
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5095626 |
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07392029 |
Aug 10, 1989 |
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07124925 |
Nov 23, 1987 |
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Current U.S.
Class: |
206/204 ;
257/E23.038; 257/E23.054; 257/E23.124; 257/E23.126 |
Current CPC
Class: |
B32B 27/18 20130101;
B32B 2307/7246 20130101; H01L 23/49506 20130101; H01L 2224/48247
20130101; H01L 2224/45124 20130101; H01L 2924/01019 20130101; H01L
2924/14 20130101; B65D 81/266 20130101; H01L 2924/01013 20130101;
H05K 13/0084 20130101; B32B 2327/06 20130101; H01L 24/45 20130101;
H01L 2924/00014 20130101; B32B 2323/04 20130101; H01L 23/49582
20130101; B32B 2311/24 20130101; H01L 2924/01027 20130101; H01L
2924/01079 20130101; H01L 2924/014 20130101; B32B 27/304 20130101;
H01L 2924/01005 20130101; H01L 2924/01007 20130101; H01L 2224/49171
20130101; H01L 2924/20753 20130101; Y10T 29/49121 20150115; H01L
2224/32245 20130101; H01L 21/67121 20130101; H01L 2924/0105
20130101; H01L 23/3107 20130101; H01L 2924/01006 20130101; H01L
2924/01047 20130101; B32B 27/08 20130101; H01L 24/48 20130101; H01L
2924/01029 20130101; H01L 2924/12042 20130101; B32B 2439/00
20130101; H01L 23/3135 20130101; H01L 2224/48699 20130101; B65D
79/02 20130101; H01L 2924/01078 20130101; Y10S 428/922 20130101;
H01L 24/49 20130101; H01L 2224/45147 20130101; H01L 2224/48091
20130101; H01L 2224/48227 20130101; H01L 2924/01015 20130101; H01L
2924/181 20130101; H01L 2224/48599 20130101; H01L 2924/01018
20130101; H01L 24/73 20130101; H01L 2224/73265 20130101; H01L
2924/01014 20130101; H01L 2924/01075 20130101; Y10S 174/08
20130101; H01L 2224/45144 20130101; H01L 2224/48465 20130101; B32B
27/32 20130101; H01L 2224/45015 20130101; H01L 2224/8592 20130101;
H01L 2224/45124 20130101; H01L 2924/00014 20130101; H01L 2224/45144
20130101; H01L 2924/00014 20130101; H01L 2224/45147 20130101; H01L
2924/00014 20130101; H01L 2224/48091 20130101; H01L 2924/00014
20130101; H01L 2224/45015 20130101; H01L 2924/20753 20130101; H01L
2224/48465 20130101; H01L 2224/48227 20130101; H01L 2224/48465
20130101; H01L 2224/48227 20130101; H01L 2924/00 20130101; H01L
2224/49171 20130101; H01L 2224/48465 20130101; H01L 2924/00
20130101; H01L 2224/49171 20130101; H01L 2224/48227 20130101; H01L
2924/00 20130101; H01L 2924/00012 20130101; H01L 2224/49171
20130101; H01L 2224/48247 20130101; H01L 2924/00 20130101; H01L
2224/73265 20130101; H01L 2224/32245 20130101; H01L 2224/48247
20130101; H01L 2924/00012 20130101; H01L 2224/48465 20130101; H01L
2224/48247 20130101; H01L 2924/00012 20130101; H01L 2224/48465
20130101; H01L 2224/48247 20130101; H01L 2924/00 20130101; H01L
2224/48465 20130101; H01L 2224/48091 20130101; H01L 2924/00
20130101; H01L 2224/73265 20130101; H01L 2224/32245 20130101; H01L
2224/48227 20130101; H01L 2924/00 20130101; H01L 2224/45015
20130101; H01L 2924/00014 20130101; H01L 2924/20753 20130101; H01L
2924/00014 20130101; H01L 2224/05599 20130101; H01L 2924/12042
20130101; H01L 2924/00 20130101; H01L 2924/181 20130101; H01L
2924/00012 20130101 |
Class at
Publication: |
206/204 |
International
Class: |
B65D 081/26 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 1986 |
JP |
278610/1986 |
Aug 21, 1987 |
JP |
206290/1987 |
Claims
What is claimed is:
1. A method of manufacturing a packaged device, comprising steps
of: providing a moisture proofing bag; providing a surface mount
semiconductor device, to be mounted on a printed circuit board, the
surface mount semiconductor device being a device which will be
subject to heat when the surface mount semiconductor device is
surface mounted on a printed circuit board; and sealing the surface
mount semiconductor device in the moisture proofing bag with
desiccant.
2. A method of manufacturing a packaged device according to claim
1, wherein the step of sealing includes heat sealing the moisture
proofing bag.
3. A method of manufacturing a packaged device according to claim
1, wherein the step of sealing includes heat sealing the moisture
proofing bag after deaeration in the step of sealing.
4. A method of manufacturing a packaged device according to claim
1, wherein the moisture proofing bag includes a polyethylene layer,
and wherein the step of sealing includes heat sealing the
polyethylene layer.
5. A method of manufacturing a packaged device according to claim
1, wherein the moisture proofing bag is made of a laminate
film.
6. A method of manufacturing a packaged device according to claim
1, wherein the laminate film has a barrier layer for preventing
intrusion of moisture, an inner charge preventing layer formed
inside of said barrier layer and an outer charge preventing layer
formed outside of the barrier layer.
7. A method of manufacturing a packaged device according to claim
1, wherein the moisture proofing bag includes a layer for
preventing intrusion of moisture.
8. A method of manufacturing a packaged device according to claim
1, wherein the step of sealing includes heat sealing the moisture
proofing bag.
9. A method of manufacturing a packaged device according to claim
1, wherein the surface mount semiconductor device has a surface
mount plastic package encapsulating a semiconductor device.
10. A method of manufacturing a packaged device according to claim
1, wherein, in the step of sealing, a member for storing the
surface mount semiconductor device is sealed in the moisture
proofing bag.
11. A method of manufacturing a packaged device according to claim
10, wherein the member for storing is a magazine.
12. A method of manufacturing a packaged device according to claim
10, wherein the member for storing is a tray.
13. A method of manufacturing a packaged device according to claim
10, wherein the step of sealing includes heat sealing the moisture
proofing bag after deaeration in the step of sealing.
14. A method of manufacturing a packaged device according to claim
1, wherein the moisture proofing bag has a caution that the device
should be prevented from absorbing moisture after opening the
bag.
15. A method of manufacturing a packaged device according to claim
14, wherein the caution is printed on a surface of the moisture
proofing bag.
16. A method of manufacturing a packaged device according to claim
14, wherein the caution is bonded on a surface of the moisture
proofing bag.
17. A method of manufacturing a packaged device according to claim
16, wherein the step of sealing includes heat sealing the moisture
proofing bag.
18. A method of manufacturing a packaged device according to claim
16, wherein the moisture proofing bag includes a polyethylene
layer, and wherein the step of sealing includes heat sealing the
polyethylene layer.
19. A method of manufacturing a packaged device according to claim
1, wherein the moisture proofing bag has a caution that the device
should be used rapidly after opening the bag.
20. A method of manufacturing a packaged device according to claim
1, wherein the moisture proofing bag has a caution that the device
should be kept in an environment of low humidity.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a technique for preventing peel of
a package interface and crack when a surface package type
semiconductor package is mounted to a packaging substrate such as a
printed circuit board.
[0002] In surface mount package type semiconductor packages such as
a small outline package (SOP), a squad flat package (QFP), a
plastic leaded chip carrier (PLCC), and the like, the size and
thickness of the packages are more and more reduced in order to
cope with the increase in the size of a semiconductor chip stored
in the package and package strength tends to decrease.
[0003] Therefore, it has become difficult to produce a thin resin
molded IC having high reliability.
[0004] Incidentally, mentioned can be made of "IC PACK-AGING
TECHNIQUE", published by Kogyo Chosakai K. K., Jan. 15, 1980, pp.
135-156, as a prior art reference describing surface package type
semiconductor packages.
[0005] Furthermore, as disclosed in Japanese Patent Laid-Open No.
178877/1986 by Otsuka et al. (Aug. 11, 1986), a proposal has been
made to put a desiccant into a magazine or to seal a conveying tray
in a bag of a vinyl sheet or the like.
SUMMARY OF THE INVENTION
[0006] When examining packaging reliability and strength of these
thin type packages, the inventors of the present invention have
found out that when heat is applied to the package when
surface-mounting the package to a mounting substrate such as a
printed circuit board such as at the time of solder reflow, a
moisture that has entered the package causes drastic volume
expansion and peel of the package interface and crack develops.
[0007] To cope with this problem, it has been customary to bake the
package at 125.degree. C., for example, for a period as long as 16
to 24 hours before solder reflow, but this method is believed
inefficient because a furnace for baking must be prepared and
particularly because baking must be made for the long period.
[0008] As a result of examination of the origin of the moisture
causing the crack described above, the inventors of the invention
have clarified that the moisture in the air enters the package
during the period from transfer mold of a chip component by a resin
to solder reflow and is likely to dew.
[0009] Though the Otsuka et al. method described already provides a
considerable effect, the problem cannot be solved completely by
this method in view of the recent product situation where the
thickness and size of the packages are reduced more and more to
store greater chips and of the severe environment where the
products are shipped by airplanes.
[0010] It is therefore an object of the present invention to
provide a technique which prevents interface peel and crack of a
surface mount package type package.
[0011] It is another object of the present invention to provide a
highly reliable high density packaging technique.
[0012] It is still another object of the present invention to
provide an efficient solder reflow technique.
[0013] It is still another object of the present invention to
provide an effective shipment method of electronic components.
[0014] It is a further object of the present invention to provide
an effective preservation method of semiconductor devices sealed by
a thin resin package.
[0015] It is still another object of the present invention to
provide high freedom for the conditions of executing an assembly
process.
[0016] It is still another object of the present invention to
provide an assembly process which will be suitable for surface
mount package.
[0017] It is still another object of the present invention to
provide an efficient surface mount type packaging technique.
[0018] It is still another object of the present invention to
improve moisture-proofness of resin-molded ICs, or the like.
[0019] It is still another object of the present invention to
provide a packaging technique of resin-molded ICs or the like which
will be suitable for automatic packaging.
[0020] It is still another object of the present invention to
provide a preservation method of ICs, components, electronic
devices, and the like, which have high moisture-proofness and do
not require baking even when stored for a long period.
[0021] It is still another object of the present invention to
provide a packaging method of electronic components such as ICs
which can easily discriminate the existence of pin-holes.
[0022] It is still another object of the present invention to
provide a moisture-proofing packaging technique of ICs or the like
which do not need a large space requirement.
[0023] It is still another object of the present invention to
provide a moisture-proofing packaging technique of ICs or the like
which can easily judge the degree of hygroscopicity of ICs or the
like.
[0024] It is still another object of the present invention to
provide a moisture-proofing bag having a display portion for
displaying the degree of hygroscopicity, of ICs or the like.
[0025] It is still another object of the present invention to
provide a package member for a surface package type packages which
can easily represent the degree of hygroscopicity of ICs or the
like.
[0026] It is still another object of the present invention to
provide an efficient surface mounting method of resion-molded ICs
or the like.
[0027] It is still another object of the present invention to
provide an assembly process which will be suitable for resin-molded
electronic components storing therein integrated circuits having a
large chip size.
[0028] It is still another object of the present invention to
provide a shipment method of electronic devices such as
resin-molded ICs which will be suitable for the shipment of the
electronic devices by air planes.
[0029] It is still another object of the present invention to
provide a moisture-proofing packaging technique of resin-molded ICs
or the like which does not undergo dewing even at low
temperatures.
[0030] It is still another object of the present invention to
provide a technique which can confirm the state of hygroscopicity
of a moisture-proofing package inside the package from the outside
thereof.
[0031] These and other objects and novel features of the present
invention will become more apparent from the following detailed
description when taken in conjunction with the accompanying
drawings.
[0032] Among the inventions disclosed herein, a typical example is
as follows.
[0033] In the present invention, a surface mount package type
package stored in a magazine is put into an interior box, the
interior box is then placed into a transparent resin bag using, as
the base, a polyester having moisture permeability of up to
2.0/m.sup.2.multidot.24 hrs, for example, and having a surface
intrinsic resistance of 10.sup.6 Ohms on the outside and up to
10.sup.11 Ohms on the inner side, and the open portion of the bag
is heat-sealed after removing the air. Furthermore, a desiccant
such as silica gel is put into the interior box.
[0034] According to this arrangement described above, the surface
mount package type package is stored in the interior box and the
moisture-proofing bag outside the box and sealed completely by
deaeration and heat seal and is free from the influences of
external moisture. Therefore, the interface peel and crack of the
package do not occur even after solder reflow without the need of
the troublesome baking operation. Particularly because the
polyester having moisture permeability of up to 2.0
g/m.sup.2.multidot.24 hours is used as the base of the resin bag in
the present invention, moisture-proofness is high and heat seal is
possible so that the effect of checking intrusion of the external
air is high. The surface intrinsic resistance of the bag is up to
10.sup.11 ohms on its inner surface and up to 10.sup.6 ohms on its
outer surface in order to prevent any charge. Furthermore, silica
gel is placed between the magazine and the wall surface of the
interior box in the present invention in order to absorb the
moisture so that the surface package type package is not much
affected by the external moisture.
[0035] Still another example of the inventions disclosed herein is
as follows.
[0036] Namely, the present invention provides a transparent
moisture-proofing packaging bag for moisture-proofing and packaging
an electronic component, which bag is equipped with a moisture
indicator for detecting the degree of hygroscopicity inside the
moisture-proofing bag at a portion which is visible from
outside.
[0037] According to the means described above, since the moisture
indicator for detecting the moisture inside the transparent
moisture-proofing bag is disposed at a position visible from
outside, the degree of hygroscopicity of the bag can be confirmed
from outside the bag.
[0038] Still another typical example of the inventions disclosed
herein provides a package which comprises a semiconductor chip on
which at least one electronic device is formed, a resin-molding
member covering at least a part of the main plane of the
semiconductor chip, and a moisture-proofing bag comprising a
multi-layered film containing at least one metal sheet, for cutting
off the resin-molding member from outside.
[0039] Still another typical example of the inventions disclosed
herein provides a package of a number of (about 10) resin-molded
semiconductor devices which are stored in a plastic magazine, whose
outside portion is sealed air-tight by a moisture-proofing
film.
[0040] Still another typical example of the inventions disclosed
herein provides an air-tight package made of a moisture-proofing
film and including a number of resin-molded semiconductor devices,
a plurality of device storing magazines storing therein a line of
resin-molded semiconductor devices, an interior box for aligning a
plurality of magazines and storing them therein while they are in
close contact with one another, a packaging bag made of a
moisture-proofing sheet member, storing therein the interior box
and sealed air-tight, and a desiccant placed in the packaging
bag.
[0041] Still another typical example of the inventions discloses
herein provide an air-tight package for a number of surface mount
package type resin-molded semiconductor devices which comprises an
exterior box made of a cardboard, a number (at least five to six)
of packaging bags made of a moisture-proofing film and sealed
air-tight, a plurality of interior boxes made of paper and stored
in the packaging bag, a plurality of tube-like magazines for
conveying semiconductor devices, stored in the interior boxes,
respectively, a number of surface package type resin-molded
semiconductor integrated circuit devices stored in the magazines,
respectively, and a desiccant stored in each of the interior
boxes.
[0042] Still another typical example of the inventions disclosed
herein provides an air-tight package for a large number of surface
mount package type resin-molded semiconductor integrated circuit
devices which comprises an exterior box made of cardboard, a
plurality of packaging bags made of a moisture-proofing film and
sealed air-tight inside the exterior box, at least one conveying
auxiliary member for protecting a number (at least five to six) of
resin-molded semiconductor devices stored in the packaging bags, a
number of resin-molded semiconductor integrated circuit devices
stored in or on the auxiliary member, and a desiccant stored in
each of the packaging boxes.
[0043] Still another typical example of the inventions disclosed
herein provides an air-tight package for at least one resin-molded
semiconductor device which comprises a packaging bag made of a
moisture-proofing film, at least one conveying auxiliary member
stored in the packaging bag, at least one resin-molded
semiconductor device stored in the packaging bag and stored in or
on the auxiliary member, and a desciccant placed in the packaging
bag.
[0044] Still another typical example of the inventions disclosed
herein provides an air-tight package for at least one resin-molded
semiconductor device which comprises a packaging bag made of a
moisture-proofing film and sealed air-tight, at least one
resin-molded semiconductor device stored in the packaging bag, and
a desiccant placed in the packaging bag.
[0045] Still another typical example of the inventions disclosed
herein provides an air-tight package for at least one resin-molded
semiconductor device which comprises a packaging bag made of a
moisture-proofing film and sealed air-tight, at least one
resin-molded semiconductor device stored in the packaging bag, and
a desiccant stored in the packaging bag or formed on the inner
surface of the packaging bag.
[0046] Still another typical example of the inventions disclosed
herein provides a package comprising a semiconductor chip on which
at least one electronic device is formed, a moisture-proofing bag
for cutting off the semiconductor chip from outside, and humidity
display means disposed in the moisture-proofing bag and capable of
being recognized from inside.
[0047] Still another typical example of the inventions disclosed
herein provides a package comprising a tube-like magazine for
storing a line of a number (at least five to six) of resin-molded
semiconductor devices, a number of resin-molded semiconductor
devices stored in the magazine, and humidity display means disposed
in the magazine in such a manner as to be visible from outside.
[0048] Still another typical example of the inventions disclosed
herein provides a package for a large number (at least ten) of
resin-molded semiconductor devices, sealed air-tight by a
moisture-proofing film, said package being equipped thereinside
with humidity display means in such a manner as to be visible from
outside.
[0049] Still another typical example of the inventions disclosed
herein provides an air-tight package made of a moisture-proofing
film, which comprises a number of resin-molded semiconductor
devices, a plurality of device storing magazines for storing
therein a number of resin-molded semiconductor devices aligned in a
line, an interior box for storing therein a plurality of magazines
while being aligned and in close contact with one another, a
packaging bag for storing therein the interior box, made of a
moisture-proofing sheet and sealed air-tight, and humidity display
means disposed inside the packaging bag in such a manner as to be
visible from outside.
[0050] Still another typical example of the inventions disclosed
herein provides an air-tight package for a number of surface
package type resin-molded semiconductor integrated circuit devices,
which comprises an exterior box made of cardboard, a number (at
least five to six) of packaging bags made of a moisture-proofing
film, sealed air-tight and stored in the exterior box, a plurality
of interior boxes made of paper and stored in the packaging bag, a
plurality of tube-like magazines for conveying semiconductor
devices, stored in the interior boxes, respectively, a number of
surface mount package type resin-molded semiconductor integrated
circuit devices stored in a plurality of magazines, respectively,
and humidity display means for displaying an internal humidity of
said packaging bag, disposed inside the packaging bag in such a
manner as to be visible from outside the packaging bag.
[0051] Still another typical example of the inventions disclosed
herein provides an air-tight package for a number of surface
package type resin-molded semiconductor integrated circuit devices
which comprises an exterior box, a plurality of packaging bags made
of a moisture-proofing bag and stored in the exterior box, at least
one conveying auxiliary member for protecting a number (five to
six) of resin-molded semiconductor devices stored in the packaging
bag, a number of resin-molded semiconductor integrated circuit
devices stored in or on the auxiliary member, and humidity display
means for displaying the internal humidity of the packaging bag,
disposed in the packaging bag in such a manner as to be visible
from outside.
[0052] Still another typical example of the inventions disclosed
herein provide an air-tight package for at least one resin-molded
semiconductor device, which comprises a packaging bag made of a
moisture-proofing film and sealed air-tight, at least one conveying
auxiliary member stored in the packaging bag, at least one
resin-molded semiconductor device stored in the packaging bag and
stored in or on the auxiliary member, and humidity display means
disposed in the packaging bag in such a manner as to be visible
from outside.
[0053] Still another typical example of the inventions disclosed
herein provides an air-tight package for at least one resin-molded
semiconductor device, which comprises a packaging bag made of a
moisture-proofing bag and sealed air-tight, at least one
resin-molded semiconductor device stored in the packaging bag, and
humidity display means disposed in the packaging bag in such a
manner as to be visible from outside.
[0054] Still another typical example of the inventions disclosed
herein provides an air-tight package for at least one resin-molded
semiconductor device, which comprises a packaging bag made of a
moisture-proofing film and sealed air-tight, at least one
resin-molded semiconductor device stored in the packaging bag, and
a drying member stored or formed inside the packaging bag in such a
manner as to be visible from outside.
[0055] Still another typical example of the inventions disclosed
herein provides an air-tight package for a number of resin-molded
semiconductor devices, which comprises a carrier tape made of a
first moisture-proofing resin sheet and having device storing
recesses, a plurality of resin-molded semiconductor devices stored
in the recesses, and a second moisture-proofing resin sheet
covering the upper surface of the recesses and sealed in such a
manner as to keep the inside of the recesses air-tight.
[0056] Still another typical example of the inventions disclosed
herein provides a packaging method of resin-molded semiconductor
devices, which comprises the steps of preserving the resin-molded
devices in a moisture-proofing bag lest they should absorb
moisture, taking out the resin-molded devices from the
moisture-proofing bag, and placing the resin-molded devices on a
wiring substrate and soldering the leads of the resin-molded
devices to the wirings on the wiring substrate under such a
condition where the resin-molded portion receives thermal
impact.
[0057] Still another typical example of the inventions disclosed
herein provides a method of shipping a large number of resin-molded
semiconductor devices by an air plane, which comprises sealing
air-tight the resin-molded semiconductor devices together with a
desiccant in a moisture-proofing bag.
[0058] Still another typical example of the inventions disclosed
herein provides a method of fabricating resin-molded semiconductor
devices, which comprises the steps of sealing a semiconductor chip
and inner leads by a resin, putting an ink mark to the resulting
resin-molded member, exposing the resin-molded member as a whole
after marking to a high temperature for baking the ink, and sealing
airtight the devices after completion before they absorb
moisture.
[0059] Still another typical example of the inventions disclosed
herein provides a method of fabricating a semiconductor memory
device, which comprises the steps of fixing lead to semiconductor
chip holding portions made of the same metal sheet as that of the
leads through one of the main planes of the tip, bonding pads on
the other main plane of the chip to inner leads by a bonding wire,
coating an organic resin causing less occurrence of .alpha.-rays on
at least a region of the other main plane of the chip, where memory
cells are formed, forming a resin-molded member from which a
plurality of leads projects, by molding the chip, the wires, the
chip holding members and the inner leads by a resin, and packaging
the resin-molded member by a moisture-proofing bag lest the
resin-molded member absorbs the moisture.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] FIG. 1 is a perspective view of a package in accordance with
the first embodiment of the present invention;
[0061] FIG. 2 is a perspective view of an interior box in the first
embodiment described above;
[0062] FIG. 3 is a perspective view showing an example of a
magazine;
[0063] FIG. 4 is an explanatory sectional view of the end portion
of the magazine;
[0064] FIG. 5 is an explanatory view of an example of a bag;
[0065] FIG. 6 is a perspective view showing the appearance and
construction of a transparent moisture-proofing packaging bag in
accordance with the second embodiment of the present invention;
[0066] FIG. 7 is an enlarged sectional view taken along line II-II
of FIG. 6 and shows the fitting portion of a humidity indicator
fitted to the inner side surface of a transparent bag-like
moisture-proofing member;
[0067] FIG. 8 is a partially cut-away perspective view showing the
structure of the transparent bag-like moisture-proofing member of
the moisture-proofing bag shown in FIG. 6;
[0068] FIG. 9 is a perspective view showing the appearance and
construction of a transparent moisture-proofing packaging bag in
accordance with the third embodiment of the present invention;
[0069] FIG. 10 is an enlarged sectional view taken along line II-II
of FIG. 9 and is an enlarged sectional view of a humidity indicator
fitted to the inner side surface of a transparent bag-like
moisture-proofing member;
[0070] FIG. 11 is a partially cut-away perspective view showing the
structure of an opaque bag-like moisture-proofing member of the
moisture-proofing packaging bag shown in FIG. 9;
[0071] FIGS. 12 to 17 are sectional views showing the appearance of
resin-molded semiconductor devices to which the first to third
embodiments of the present invention are applied;
[0072] FIGS. 18 to 21 show examples of conveying auxiliary members
used in the first to third embodiments of the present invention,
respectively;
[0073] FIG. 22 is an explanatory view showing in detail the
packaging method in the first to third embodiments of the present
invention;
[0074] FIG. 23 is a sectional view of a memory IC device dealt with
in the first to third embodiments of the present invention;
[0075] FIG. 24 is a schematic view showing the completed state of
surface packaging in the first to third embodiments of the present
invention; and
[0076] FIG. 25 is a schematic view of a solder dipping method of a
similar package.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0077] Hereinafter, the present invention will be described more
definitely with reference to some preferred embodiments thereof
shown in the accompanying drawings.
[0078] [Embodiment 1]
[0079] A magazine 2 is stored in an interior box 1 made of paper,
as shown in FIG. 2. An example of the magazine is shown in FIG. 3.
A surface mount package type semiconductor package 3 is packaged
into the magazine 2 and a stopper 4 is fitted to the end portion of
the magazine 2 in order to prevent projection of the package 3 from
the magazine 2.
[0080] A plurality of packages 3 are packaged into the magazine
2.
[0081] Silica gel 5 is put between the wall of the interior box 1
and the side surfaces of the magazine 2 as shown in FIG. 2.
Preferably, the silica gel 5 is put into the end portions of the
magazine for absorbing moisture. A flange 7 of a lid 6 is folded
inward and the lid 6 is closed. When the package 3 is taken out by
lifting up the lid 6, the end open side of the lid 6 is first
affected by external moisture. For this reason, it is advisable to
place the silica gel on the open side of the lid.
[0082] The interior box 1 is put into a bag 8 such as shown in FIG.
5 and after deaeration, the open portion 9 of the bag 8 is
heat-sealed.
[0083] The bag 8 is made of a transparent, electrically conductive
bag using a polyester having moisture permeability of up to 2.0
g/m.sup.2.multidot.24 hrs as the base.
[0084] If the bag 8 is transparent, it is very convenient for the
management of the products because the kind of products, quantity,
production lot number, and so forth, are put usually on the surface
of the interior box 1.
[0085] An example of the resin films constituting the conductive
bag 8 is a laminate film prepared by laminating a polyethylene
containing an antistatic agent kneaded therein, a polyester film, a
carbon conductive layer and an acrylic resin protective film in
order named from the inside, and further coating a vinylidene
chloride film on the laminate. To prevent charge of IC(s) inside
the package 8, the surface intrinsic resistance of the conductive
bag 8 is up to 10.sup.6 ohms on the outer surface and up to
10.sup.11 ohms on the inner surface.
[0086] Cautions to the effect that the devices should be used
rapidly after opening the bag and the bag should be kept in the
environment of low humidity are printed on the surface of the
conductive bag 8 or a label 10 bearing such cautions is bonded to
the conductive bag 8.
[0087] In accordance with the present invention, the surface mount
package type package 3 is kept in the moisture-proofing bag 8 and
is sealed completely by deaeration and heat seal 9. Since the
silica gel 5 absorbs the moisture on the opening side and the
package 3 is not affected by the external moisture, a troublesome
baking operation becomes unnecessary and even after solder reflow,
peel of interface and crack of the package can be prevented.
[0088] Other desiccants can be used in the embodiment described
above in place of silica gel.
[0089] [Embodiment 2]
[0090] A second embodiment of the present invention will be
explained definitely with reference to the drawings.
[0091] In FIGS. 6 to 8 useful for explaining this embodiment, like
reference numerals are used to identify like constituents and
repetition of explanation of their function will be omitted.
[0092] FIG. 6 is a perspective view showing the appearance and
structure of a transparent moisture-proofing packaging bag of this
embodiment.
[0093] As shown in FIG. 6, the transparent moisture-proofing
packaging bag of this embodiment is made of a transparent bag-like
moisture-proofing member 11. A plurality of electronic components
12 such as surface mount package type semiconductor devices are
stored in a container 13 and the containers 13 are stored in an
interior box 14. Furthermore, the interior box 14 is stored in the
bag-like moisture-proofing member 11, and both of its end portions
11A, 11B are sealed. When moisture-proofing packaging is made, a
humidity indicator 15 for detecting the humidity inside the
moisture-proofing packaging bag 17 is disposed on the inner side
surface of the transparent bag-like moisture-proofing member 11 at
a position where the indicator 15 can be seen from outside.
[0094] Examples of this humidity indicator 15 are as follows.
[0095] 1. A caution is printed on the inner side surface of the
transparent bag-like moisture-proofing member 11 by an ink
containing a material which changes the color by moisture, such as
cobalt chloride, which serves as the humidity indicator 15. For
example, the caution reads as "When the color of this caution
changes from blue to thin violet, take out surface package type
semiconductor devices from the bag and bake them at 125.degree. C.
for 24 hours".
[0096] 2. As shown in FIGS. 6 and 7, the humidity indicator
(humidity detection label) 15 is bonded to the inner side of the
transparent bag-like moisture-proofing member 11 by an adhesive 16
having vent holes 16A so that it can be confirmed from outside.
This humidity detection label is prepared, for example, by letting
paper made of a pulp absorb a material which changes color by
humidity, such as cobalt chloride.
[0097] 3. As shown in FIG. 6, the humidity indicator (humidity
detection label) 15 is bonded to the interior box 14 inside the
moisture-proofing packaging bag 17 or the caution is printed there
by the material which changes color by moisture such as cobalt
chloride.
[0098] Incidentally, when the humidity indicator (humidity
detection label) 15 is bonded in the items 2 and 3 described above,
there is no need to print the caution by the material which changes
the color such as cobalt chloride.
[0099] Next, the structure of the transparent bag-like
moisture-proofing member 11 comprises a laminate sheet as shown in
FIG. 8.
[0100] In FIG. 8, reference numeral 18 represents a polyethylene
layer into which an antistatic agent is kneaded. This is the
innermost layer of the moisture-proofing packaging bag 17. The
polyethylene layer 18 containing the antistatic agent is 63
.mu.m-thick, for example, and has the functions of preventing
frictional charge, heat sealability, openability, and so forth. A
polyester film layer 19 having a pin-hole proofing function is
disposed on the polyethylene layer 18 containing the antistatic
agent. A polyester film layer 20 having a barrier layer for
preventing intrusion of moisture is disposed on the polyester film
layer 19. The barrier layer 20 is prepared, for example, by coating
a vinylidene chloride film on a 14 .mu.m-thick polyester film. A
polyester film layer 21 (which is 12 .mu.m thick) is disposed on
the barrier layer 20 prepared by coating vinylidene chloride on the
polyester film (14 .mu.m thick), and a 1 .mu.m thick, for example,
carbon conductive layer 22 is disposed on the polyester film 21.
The polyester film 21 has the function of reinforcing mechanical
strength and dielectric resistance while the carbon conductive
layer 22 has the function of preventing charge. The carbon
conductive layer 22 is devoid of degradation with time and does not
have humidity dependence. The material of the protective layer 23
has properties such that it protects the carbon conductive layer
22, prevents the occurrence of carbon flake dust and has high
abrasion resistance and printability.
[0101] Next, the method of using the humidity indicator 15 in the
moisture-proofing packaging bag 17 will be explained briefly.
[0102] First of all, the bag-like moisture-proofing member 11 which
is equipped with the humidity indicator 15 for detecting the
internal humidity of the moisture-proofing package 17 on the inner
side surface of the transparent bag-like moisture-proofing member
11 at a position where the indicator is visible from outside is
prepared, as shown in FIG. 7.
[0103] A plurality of containers 13 storing therein a plurality of
electronic components 12 such as surface package type semiconductor
devices are put into the interior box 14, the interior box 14 is
then put into the bag-like moisture-proofing member 11 and its both
end portions 11A and 11B are sealed for moisture-proofing
packaging.
[0104] If the color of the humidity indicator 15 or the caution
changes from blue to thin violet at the time of use of the
electronic components 12 such as the surface mount package type
semiconductor devices, the electronic components 12 are taken out
from the moisture-proofing packaging bag 17, are then baked at
125.degree. C. for 24 hours and packaging is then made by solder
reflow, infrared lamp or vapor phase reflow.
[0105] As can be understood from the description given above, since
this embodiment disposes the humidity indicator 15 for detecting
the internal humidity of the transparent moisture-proofing bag 17
at the position where it is visible from outside, the state of
hygroscopicity inside the bag 17 can be confirmed from outside the
bag. Accordingly, management of the moisture-proofing bags 17 can
be made easily.
[0106] This embodiment can be applied to packaging of all those
electronic components other than the surface mount package type
semiconductor devices described above which are affected by
humidity.
[0107] [Embodiment 3]
[0108] The third embodiment of the present invention and a
semiconductor process which is common to the foregoing two
embodiments will be explained with reference to the drawings.
[0109] Hereinafter, the description will be made primarily on DRAM
by way of example.
[0110] (1) Fabrication Process in General:
[0111] Since the structure and processes of the semiconductor chip
(DRAM, logic IC) as the essence of the semiconductor devices
(integrated circuit devices, electronic devices) dealt with in the
present invention are described in U.S. Pat. No. 4,612,565 (U.S.
Ser. No. 783,531, filed Oct. 3, 1985) and U.S. Pat. No. 4,625,227
(U.S. Ser. No. 744,151, filed Jun. 13, 1985). Therefore, the
description will be made by referring partly to these
references.
[0112] After a wafer step is complete, a wafer is split into each
chip by dicing using a rotary blade. The fabrication steps before
and after the wafer step are described in "Electric Integrated
Circuits", John Allison, 1975, by McGraw Hill Book Company, pp.
5-10, particularly in FIG. 1.3 (p. 7). As to the dicing technique,
refer to U.S. Pat. No. 4,016,855 (U.S. Ser. No. 608,733, field Aug.
28, 1975).
[0113] Thereafter, each chip is die-bonded to a lead frame. For
detail of die-bonding of various kinds of chips, refer to U.S.
patent application Ser. No. 256,110 (filed Apr. 21, 1981), U.S.
patent application Ser. No. 874,121 (filed Jun. 13, 1986), U.S.
patent application Ser. No. 845,332 (filed Mar. 21, 1986), U.S.
patent application Ser. No. 843,611 (filed Mar. 25, 1986), U.S.
patent application Ser. No. 898,534 (filed Aug. 21, 1986), U.S.
patent application Ser. No. 740,420 (filed Jun. 3, 1985), U.S.
patent application Ser. No. 758,030 (filed Jul. 23, 1985) and U.S.
patent application Ser. No. 767,598 (filed Aug. 20, 1985).
[0114] Next, each bonding pad of each pellet and the inner lead
terminal of the lead frame are bonded by a bonding wires (about 30
.mu.m thick) of Cu, At, Au, or the like. Besides the various U.S.
patents and patent applications described above, refer also for the
detail of this bonding technique to U.S. Pat. No. 4,564,734 (U.S.
Ser. No. 476,268, filed Mar. 17, 1983), U.S. Pat. No. 4,301,464
(U.S. Ser. No. 55,070, filed Jul. 5, 1979), U.S. patent application
Ser. No. 898,535 (filed Aug. 21, 1986), and U.S. patent application
Ser. No. 723,645 (filed Apr. 16, 1985).
[0115] Furthermore, an about 20 to 200 .mu.m-thick high purity
polyimide layer or silicon resin layer is formed by potting on the
chip after completion of bonding in order to prevent any soft
errors by .alpha.-rays. For the detail of resin coating, refer to
U.S. patent application Ser. No. 256,110. Resin coating for
preventing the .alpha.-ray soft error may be carried out during the
wafer process. At this time, a suitable thickness is from about 10
.mu.m to about 80 .mu.m and the resin coating is formed by the
combination of spin coating with photolithography in such a manner
as to cover at least the memory cell mat.
[0116] After wire bonding is complete, the lead frame is molded
into an epoxy resin material by transfer mold. As to the molding
technique, refer to various U.S. patents and patent applications
described above as well as to "VLSI Technology", S. M. Sze, 1983,
by McGraw-Hill Book Company, pp. 574-581.
[0117] After molding is complete, the lead frame is withdrawn from
the molding die and after any fins on the lead are completely
removed, the unnecessary portions of the lead frame are cut off,
the molded member is cut away from the frame and the leads are
shaped in a desired shape.
[0118] After these steps, the products are selected and marking is
applied to the approved products. This marking step may be made
before cutting the leads. In other words, Sn or the like is plated
to the surface of the exposed lead frame after resin molding by
electroplating. Thereafter, the resin molded member and the exposed
surface of the lead frame are cleansed (washed with water) to
remove the plating solution attaching to them, and after they are
dried, they are put to an automatic marking machine for applying
the mark.
[0119] In this marking, marks representing the kind of products,
class, and the like, are simultaneously put to the resin-molded
member such as MOS semiconductor devices by offset marking using a
rotary drum (transfer drum) or relief direct mark while the lead
frame to which a plurality of semiconductor devices are fixed is
moved in a predetermined direction. At this time, static
electricity develops between the transfer drum or the relief and
the resin molded member, but since the frame is kept as a whole at
the same potential, the static electricity does not affect the
interior of the semiconductor pellet but is grounded. Thereafter,
the printed marks are baked or dried by a ultraviolet or infrared
dryer or mere heat-treatment and adhered tightly to the resin
molded member.
[0120] Thereafter, each semiconductor device is separated by
punching, cutting and bending and each lead of each MOS
semiconductor device or the like becomes simultaneously an
independent lead . The leads are bent in the L-shape on the same
side and a dual-in type MOS semiconductor device or the like free
from dielectric breakdown is thus completed.
[0121] As described above, baking (mark baking) is made at
150.degree. C. for 3 to 5 hours in the case of marking by the ink.
If laser marking is employed, on the other hand, baking for drying
the ink is not particularly required. For the detail of laser
marking, refer to U.S. patent application Ser. No. 720,884 (filed
Apr. 8, 1985).
[0122] After baking is complete, the resin molded electronic
devices (such as integrated circuit devices, semiconductor devices)
are put into the moisture-proofing bag shown in the foregoing two
embodiments, either directly or through a suitable auxiliary member
(magazine, tray, tape, reel, etc.), within a few days and
preferably, within a few hours after completion, together with a
desiccant such as silica gel, and are then sealed air-tight.
[0123] Thereafter, the resin molded devices are packed into a
shipment cardboard box or the like for shipment while being sealed
in the bag.
[0124] These semiconductor devices are taken out from the
moisture-proofing bag immediately before mounting. In an ordinary
environment, they are taken out within two to three days or within
a few hours, before use. The inventors of this invention found out
that if they are exposed to the external air for more than one
week, they absorb substantially completely the moisture in the
external air. Various solder reflow processes are used for mounting
the semiconductor devices.
[0125] (2) Detail of Moisture-proofing Bag and its Film:
[0126] FIG. 9 is a perspective view showing the appearance and
structure of an opaque moisture-proofing bag of this
embodiment.
[0127] As shown in FIG. 9, the opaque moisture-proofing packaging
bag of this embodiment is made of an opaque bag-like
moisture-proofing member 11. A plurality of electronic components
12 such as surface mount package type semiconductor devices are put
into a container 13 and the containers 13 are then stored in the
interior box 14. After this interior box 14 is put into the
bag-like moisture-proofing member 31, its both end portions 32A and
32B are sealed for moisture-proofing. When moisture-proofing
packaging is made, the humidity indicator 15 for detecting the
internal humidity of the moisture-proofing bag 31 is disposed on
the inner side surface of the opaque bag-like moisture-proofing
member 31 at a position where it is visible from outside.
[0128] Next, an example of this humidity indicator 15 will be
given.
[0129] Cautions are printed on the inner side surface of the
transparent bag-like moisture-proofing member 31 by an ink
containing a material which changes the color by humidity, such as
cobalt chloride. The caustions read, for example, as "If the color
of the cautions change from blue to thin violet, take out the
surface mount package type semiconductor devices from the
moisture-proofing packaging bag and bake them at 125.degree. C. for
24 hours".
[0130] As shown in FIGS. 9 and 10, the peripheral portion of the
humidity indicator (humidity detection label) 15 is bonded directly
to the inside of a transparent window 33 disposed at a part of the
opaque moisture-proofing member 31 by an adhesive so that the
indicator can be confirmed from outside. This humidity detection
label is prepared, for example, by letting paper made of a pulp
absorb a material which changes the color by humidity, such as
cobalt chloride. For example, it is possible to let the portion of
the surface of the interior box corresponding to the window 33
absorb such a material.
[0131] As shown in FIGS. 9 and 10, the humidity indicator (humidity
detection label) 15 is printed on the interior box 14 of the
moisture-proofing packaging bag 31 or the caution is printed there
by the material which changes the color by humidity such as cobalt
chloride.
[0132] When the humidity indicator (humidity detection label) 15 is
bonded, there is no need to print the caution by the material
changing the color by humidity, such as cobalt chloride.
[0133] Next, the moisture-proofing member 34 at the transparent
window portion of the moisture-proofing packaging bag comprises a
laminate sheet as shown in FIG. 8.
[0134] On the other hand, the portions of the moisture-proofing bag
other than the transparent window 33 shown in FIG. 10 is made of an
opaque sheet having an aluminum film 35 as shown in FIG. 11.
[0135] In FIG. 11, reference numeral 36 represents a polyethylene
layer into which an antistatic agent is kneaded and which serves as
the innermost layer of the moisture-proofing packaging bag 31. The
polyethylene layer 36 containing the antistatic agent is 60 .mu.m
thick, for example, and has the functions of preventing frictional
charge, heat sealability, openability, and the like.
[0136] An aluminum foil 35 having high moisture-proofness is spread
on this polyethylene layer 36. Since aluminum is a metal, its vapor
permeability is extremely lower than that of organic films and can
effectively prevent its intrusion. This aluminum is about 10 .mu.m
thick, for example. Furthermore, an about 20 .mu.m-thick
polyethylene film layer 39 having high heat moldability is disposed
on this aluminum. A polyester film layer (which is 12 .mu.m thick)
38 having high mechanical strength and high withstand voltage is
disposed on the polyethylene film and a 1 .mu.m-thick carbon
conductive layer 37 is disposed on the polyester film layer.
Furthermore, an acrylic type protective layer 40 is disposed on the
carbon conductive layer 37. The polyester film layer 38 has the
function of reinforcing mechanical strength and dielectric
resistance while the carbon conductive layer 37 is devoid of
degradation with time and does not have humidity dependence. The
material of the protective layer 40 has properties such that it
protects the carbon conductive layer 37, prevents the carbon flake
dust and has high abrasion resistance and high printability.
[0137] Next, the method of using the humidity indicator 15 in the
moisture-proofing packaging bag 31 of this embodiment will be
explained briefly.
[0138] First of all, the bag-like moisture-proofing member 31 which
is equipped with the humidity indicator 31 disposed at the position
of the transparent window 33, where the indicator is visible from
outside, on the inner side surface of the moisture-proofing member
11 is prepared. A plurality of electronic components 12 such as the
surface mount package type semiconductor devices are stored in the
container 13, the containers 13 are then stored in the interior box
14 and after the interior box 14 is put into the bag-like
moisture-proofing member 11, its both end portions 32A and 32B are
sealed for moisture-proofing.
[0139] When the color of the humidity indicator 15 or the caution
changes from blue to thin violet when using the electronic
components 12 such as the surface mount package type semiconductor
devices, the electronic components 12 are taken out from the
moisture-proofing bag 31 and baked at 125.degree. C. for 24 hours.
Thereafter, they are mounted by solder reflow, infrared lamp or
vapor phase reflow.
[0140] As can be understood from the description given above, this
embodiment disposes the humidity indicator 15 for detecting the
internal humidity of the opaque moisture-proofing bag 31 at the
position where it is visible from outside. Accordingly, the
internal state of hygroscopicity of the bag 31 can be confirmed
from outside and its management can be made easily. Since the
moisture-proofing bag 31 is not broken, re-packaging is not
necessary after confirmation.
[0141] This embodiment can be changed or modified in various
manners.
[0142] For example, the embodiment can be applied to all those
electronic components other than the surface mount package type
semiconductor devices described above which are affected by the
influence of humidity.
[0143] (3) Detail of Resin Molded Electronic Devices as Object of
Application:
[0144] FIG. 12 shows a package which is called a "gull wing" and
generally a "Small Outline Package (SOP)".
[0145] FIG. 13 shows a surface mount package type package which is
called a "flat plastic package (FPP) or a squad flat package
(QFP)". Furthermore, FIG. 14 shows a package for use specially for
a memory or the like, which is called a "small outline J-bend
package (SOJ)". FIG. 15 shows a package which is called a "plastic
leaded chip carrier (PLCC)" and is used for high density surface
mount package. FIG. 16 shows a package which belongs to a butt lead
type and is called a "mini-squad package (MSP)".
[0146] Unlike the packages shown already, the package shown in FIG.
17 is of a type in which leads are fitted into holes of a
substrate. Therefore, it belongs to an insert type and is generally
called a "dual in-line package (DIP)".
[0147] In FIGS. 12 to 17 described above, the semiconductor chip 42
is fixed to a holder such as tabs or islands made of a thin metal
sheet through an Ag paste 43. The bonding pads on the chip and the
inner leads having the Ag spot plating layer 44 formed thereon are
subjected to ball and wedge bonding by capillary by an Au wire 45
(30 .mu.m diameter), or the like. The leads 46 are formed by
punching out from a 42-alloy or a copper alloy film. They are
transfer-molded by an epoxy resin 41.
[0148] (4) Detail of Conveying Auxiliary Member:
[0149] A large number of resin molded devices are stored in various
conveying auxiliary member and are then sealed air-tight depending
upon their applications.
[0150] The auxiliary member will now be explained.
[0151] FIG. 18 shows the state of a magazine 54 and the resin
molded devices (transistors, ICs, LSIs, etc.) stored in the
magazine 54. MSP type resin molded devices 53 are stacked
vertically inside the magazine 54 and a polyethylene sub-stopper 52
and a main stopper made of hard nitrile rubber are packed into the
end portion of the magazine. The magazine main body is made of hard
polystylol containing carbon or electrically conductive soft vinyl
chloride.
[0152] FIG. 19 shows a tray 55 as one of the auxiliary members. The
tray is made of vinyl chloride to which antistatic treatment is
applied, and the resin molded devices 53 are put into square
recesses 56 that are aligned in the form of array. In this case, it
is possible to put directly silica gel or the like into each recess
56 and to seal the upper surface air-tight by the moisture-proofing
sheet. Generally, after the trays are stacked, they are put into
the interior box made of paper and then sealed into the
moisture-proofing bag.
[0153] FIG. 20 shows an auxiliary member which is called a "tape
and reel" system. The resin molded devices 53 are held in a line on
a carrier tape 57 wound on a reel 59 through an adhesive tape 58.
After the carrier tape 57 is wound on the reel 59, the reel is
sealed air-tight one by one in the moisture-proofing bag.
[0154] FIG. 21 shows another type of the tape and reel system. In
this case, the resin molded devices 53 are stored in the square
recesses 56 formed in a line on the carrier tape 57 and their upper
surface is heat-sealed by a cover tape 60. The tape is wound on the
reel under this state and the reel is sealed moisture-tight in the
same way as above. In this case, too, the external
moisture-proofing sheet can be eliminated by changing the cover
tape 60 to the moisture-proofing sheet shown in FIG. 8 or 11 and
putting silica gel or the like into each recess 56.
[0155] Incidentally, refer to U.S. patent application Ser. No.
879,012 (filed Jun. 26, 1986) for the detail of production of
magazine and the like.
[0156] (5) Detail of Shipment Package of ICs or the Like:
[0157] FIG. 22 shows an example of a shipment package of resin
molded devices 53 (plug-in type or surface mount package type
devices). A number of resin molded devices 53 are stored in a line
inside the tube-like magazine 2 and secured fixedly by a stopper
pin 64 and a stopper filler 4. A predetermined number of magazines
are stored in the interior box 1 having low hygroscopicity, made of
paper or sheet and stored inside the bag made of the
moisture-proofing sheet such as shown in FIG. 8 or 11. The internal
pressure of the bag becomes somewhat lower than that of the
external air and deaeration is made so that the moisture-proofing
bag comes substantially into close contact with the outer surface
of the interior box and air-tight sealing is then made by
pressurization or by heating. In this manner, the interior boxes
can be stored easily in the exterior box and the storage space
becomes small.
[0158] On the other hand, the existence of any pin-holes can be
descriminated easily by putting dry N.sub.2, which may be somewhat
pressurized, into the bag in order to secure a gap between the
moisture-proofing sheet and the interior box.
[0159] Though the description given above primarily deals with the
magazine by way of example, packaging can be made substantially in
the same way as above in the case of the tray and the tape and
reel. In addition, either one or a plurality of the resin molded
ICs may be put directly into the moisture-proofing bag.
[0160] It is also possible to put and seal the auxiliary member
directly into the moisture-proofing bag without using the interior
box.
[0161] Though the desiccant is put into a paper bag or the like and
then placed inside the interior box, it may be placed at a suitable
air-tight position such as the recess of the magazine or the
carrier tape. For instance, the desiccant may be coated and
diffused on the inner surface of the moisture-proofing sheet.
[0162] As described above, a predetermined number of
moisture-proofing bags that have been sealed air-tight are stored
in the exterior box 61 made of the cardboard and sealed by the
adhesive tape 62. After the box is bound by bands 63, the box is
shipped.
[0163] As to other air-tight sealing methods, particularly the
method which uses the tray, refer to the afore-mentioned reference
Japanese Patent Laid-Open No. 178877/1986.
[0164] (6) Detail of Memory Chips and DRAM Devices:
[0165] The relationship between the sectional structure of the
memory IC device and the package in the present invention will be
explained. Here, the SOP type package will be described by way of
example.
[0166] In FIG. 23, a very large number (about 1,000,000) of FETs
constituting DRAM are formed on the upper main plane of the Si
substrate 71. On the Si substrate are formed field oxide films
forming these devices, insulation films (inorganic films) 72 made
of an inter-level PSG (phospho silicate glass), and the like. A
number of Al bonding pads 75 are disposed further thereon.
[0167] On the other hand, the Si substrate 71 is fixed on its lower
main plane to the islands or tabs 78 through the Ag paste 77. The
size of this chip 71 is about 10 mm.times.5 mm.times.0.4 mm
(high.times.wide.times.thi- ck). The lead 80 is made of the same
42-alloy as that of the islands, and partial Ag plating 79 is
disposed at the inner lead portion. After ball and wedge bonding is
made to the gap between the inner end of the lead 80 and the
bonding pad by an Au wire having a 30 .mu.m diameter, a polyimide
resin 73 is formed by potting onto substantially the entire upper
surface of the chip from above the former. Thereafter, the
structure is transfer-molded by an epoxy resin 76 in a lead frame
unit. Solder plating 81 is applied to the lead portions protruding
from the mold resin 76.
[0168] At this time, the 42-alloy member of the lead and island
portion is 0.15 mm thick, the mold resin on the upper surface of
the package is about 1 mm thick, the polyimide film is about 0.1 mm
thick, the Ag paste is about 50 .mu.m thick and the lower surface
of the mold resin is about 1 mm thick.
[0169] In the package sealed by such a thin resin, if the absorbed
moisture content is great, evaporation and expansion of the
moisture occur first on the lower surface of the tab 78 due to
drastic heating at the time of soldering and packaging.
Subsequently, peel occurs between the resin and the metal and the
package swells. The inventors found out that if the resin cannot
withstand the resulting stress at this time, package crack
develops.
[0170] (7) Detail of the Package Mounting Process:
[0171] First of all, the outline of the surface mounting process
will be given.
[0172] Desired wirings are formed on the substrate made of
glass-epoxy resin, or the like, by a Cu film or the like, and a
solder past is formed by screen printing or the like at solder
portions (foot print) on the substrate. Then, the resin molded
devices are mounted onto the solder paste by a vacuum chuck or like
means, and solder in the paste is fused for soldering by the solder
reflow method such as vapor phase reflow, heating furnace, infrared
reflow, and like means.
[0173] FIG. 24 shows the state of mounting. In the drawing,
reference numeral 91 represents the resin molded device of the SOJ
type, 92 is the resin molded device of the SOP type and 93 is the
resin molded device of the MSP type. Reference numeral 94
represents the wiring substrate and 95 is the solder which is
reflowed or dipped.
[0174] FIG. 25 shows the solder dipping method. As shown in FIG.
25(a), the resin molded device 93 of the MSP type is fixed in such
a manner that its leads are placed on the screen-printed solder
paste on the substrate 94 by the adhesive 96. Subsequently, it is
dipped downwardly into the solder stream 98 as shown in FIG. 25(b)
and is then cooled in such a manner as to attain the state shown in
FIG. 25(c).
[0175] Though the present invention has thus been described with
reference to some preferred embodiments thereof, it will be obvious
to those skilled in the art that the invention is not particularly
limited thereto but can be changed or modified in various manners
without departing from the spirit and scope thereof.
* * * * *