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Appendix E
Packaging Technologies in Japan
This appendix covers the current use of various packaging meth-
ods in Japan for high-, medium-, and low-lead counts, and presents
Japanese estimates for the 1990 time frame. The Japanese are ei-
ther using or developing four forms of packaging and interconnect
technologies:
.
tape-automated bonding (TAB);
flip chip;
elastomeric; and
~ film on frame.
Packaging and interconnect have received a great deal of atten-
tion in recent years in Japan, with impressive results. Table E.1
summarizes the progress made by individual Japanese companies.
TAB is used today in Japan predominantly for watches, cal-
culators, video games, and some high-speed computer applications
(e.g., NEC's SX-2~. There is evidence that the seven or eight major
Japanese semiconductor manufacturers are very interested in TAB
for plastic flat packages, without the conventional metal leadframe.
There is also interest in using TAB with gate array components of
moderate lead count. A leading Japanese packaging technologist
published a projection in 1985 that estimated that TAB would rep-
resent about 15 percent of the market by 1990. This 15 percent was
broken down as follows:
261
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262
APPENDIX E
TABLE E.1 Pin Counts of Gate Arrays and Rent's Rule
Company
Gate Number Rent's
Count of Pins Rule
Fujitsu
Hitachi
NEC
Toshiba
OKI
NS
200
400
700
1000
1500
3000
1270
3900
2500
2112
3192
2100
4800
6000
34
46
62
78
94
108
80
68
100
78
130
112
107
154
2.41
2.30
2.34
2.47
2.43
2.00
2.20
1.10
2.00
1.70
2.30
2.40
1.50
2.00
SOURCE: Data from Don Brown and Associates.
6 percent for calculators;
4 percent for smart cards with LSIs;
~ 3 percent single-chip plastic molded flat packages with small
lead ( 120 pins) used instead of conventional lead-
frame/wire;
0.5 percent high-speed computer modules;
0.5 percent SOS multichip assemblies; and
~ 1 percent for watches and games.
At least 14 Japanese companies have TAB and flip chip capabil-
ity. The TAB applications range from watches and thin calculators
to logic modules, although, with the exception of NEC, most TAB
logic modules are just coming out of the laboratories. Flip chip
applications are in logic and memory.
The new ceramic substrate materials under investigation by sev-
eral Japanese companies offer a variety of properties and improve-
ments that may meet future packaging needs. They offer higher
thermal conductivity (silicon carbide (SIC) and aluminum nitride
(AIN)) ~.nCt lower dielectric constants. AIN's strengths are in its Tow-
dielectric constant and relative low cost (according to Toshiba, in vol-
ume it will be slightly higher than alumina). These strengths will al-
Tow A1N to be used in many high-power, medium-speed applications.
Lastly, the development of new low-temperature firing, low-dielectric
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APPENDIX E
263
TABLE E.2 Comparison of Glass Ceramics Characteristics
Dielectric Thermal
Relative Cost Constant Conductivity
Material in 1984 (at 1 GHz) (W/cm-°K)
Silicon carbide 20 15
Beryllia 20 6.5
Aluminum nitride 15
Alumina ~
Glass ceramic 5
. .
9.0
9.5
5.0
270
240
60-140
17
10
SOURCES: Data from MCC.
constant glass ceramic offers both Tower dielectric constants and the
ability to use low-resistivity, thick-fiIm conductor systems, which wiD
permit higher signal speeds. (According to several Japanese compa-
nies using glass ceramics, lower resistivity materials permit the use of
narrower conductors that in turn reduce capacitance.) The Japanese
intend to use glass ceramics in high-performance systems. Table E.2
compares the costs, dielectric constants, and thermal conductivity as
reported by the seven principal Japanese companies.
Japanese success in investigating new substrate materials is im-
pressive, particularly the ceramic and glass-ceramic materials with
high-thermal conductivity and low-dielectric constants (SIC and
AIN). MIT] has targeted ceramics as a core technology within the
program to develop basic technologies for the next generation of
Japanese industries. As of 1987, Japanese-produced {C substrates
and packages had a 61 percent share of the world ceramics market
(Ceramics Bulletin, Vol. 62, No. 5~. Table E.3 lists the Japanese
companies actively investigating new ceramics.
Hitachi is vertically integrated, including both a chemical and
an electronics company, and has developed perhaps the most effi-
cient interplay of these two strengths. One example is its devel-
opment of beryBia-doped silicon carbide for high thermal conduc-
tivity, heat-spreading substrates for multichip, high-power bipolar
memory modules to permit air-cooling in high-performance com-
puters. Other examples are Hitachi's high-purity encapsulants and
high-quality-controlled polyimides. Toshiba has also been aggres-
sive in developing high-thermal-conductivity ceramics. Toshiba has
reported on high-thermal-conductivity aluminum nitride, and has
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264
APPENDIX E
TABLE E.3 New Ceramics Research by Japanese Companies
Other
Glass Low-Temperature
Company SiC A1N Ceramic Ceramics
Hitachi x x
NEC x x x
NTT x
Toshiba x x x
Fujitsu x x
Mitsubishi x
Shinko x
x
SOURCE: D ata from MCC.
TABLE E.4 Current and Projected Availability of Japanese Ceramics
Material
Status
Alumina
Aluminum nitride
Glans ceramic
Silicon carbide
Beryllia
In production
Direct copper-bonded product
went into production in late
1985, other products in
1987-1988
Developed; entering production
Single layer available now;
multilayer is in development
In production
SOURCE: Data from MCC.
argued that economic considerations and the ease of fabricating flat
materials make this a preferred choice.
The current and projected availability of ceramics from Japanese
vendors is described in Table E.4.
Representative terms from entire chapter:
silicon carbide
