Date Visited: October 8, 1993
Report Author: W. R. Boulton
Dr. Otsuka recently retired from Hitachi to assume a position at Meisei University, where he teaches a course on advanced information technology. He is affiliated with IEEE and chaired the VLSI workshop held in Kyoto December 1994. He teaches computer and computer packaging technology. Through workshops, he teaches engineers from Japanese companies. He has research contracts on electrical characterization of packages.
PACKAGING TECHNOLOGY IN JAPAN
Dr. Otsuka limited his formal remarks to the topic of "Main Packaging Technology in Japan (Single Chip Packaging)." He provided a number of important insights into the future developments of electronic packaging technology in Japan.
Korea or America is expected to take over long-term leadership in LCD packaging technology.
Dr. Otsuka made it clear that LSI packaging technologies have a different origin and core competence than LCD packaging technologies. The development of LCD technologies has come from the merging of TV cathode tube and silicon wafer process technologies, which gives Koreans and Americans the potential to take leadership in this area. Korea has made a strong commitment to LCD development, and recently, Samsung and Gold Star have announced massive investments of $400 million and $300 million, respectively, in TFT technology development programs through 1995.
Dr. Otsuka was not optimistic about Japanese companies maintaining leadership in CD technology. He didn't feel that large Japanese companies could work with small companies to develop such a new infrastructure. At the time, large companies were worried about small companies competing with them. Dr. Otsuka believed that Japanese companies' departmental structures were too competitive with each other to cooperate on merging new technologies. He felt that presidents cannot control their department heads. That means that they cannot develop large-scale systems like Apple did with Macintosh.
Small companies also provide a threat to large companies by their dedication to a single technology. While big companies are investing in CRT technology, they cannot give the same effort to new LCD technology. The large companies are worried about the potential of small companies. Active matrix LCDs by Japan Hosiden are a threat to Sharp because they are selling to Apple and other U.S. companies like Boeing. Companies like Sony are integrating backwards into their own components to increase profitability. That is causing a breakdown in supplier relationships and causing less coordination on new development.
In the future, Dr. Otsuka sees the United States maintaining strength in high-frequency devices like computers and microprocessors. He expects Korea will be strong in memories and LCDs in the future. Low-cost micro assembly applications will remain the strength of Japan in the future. If Japan loses low-cost QFP packaging technology, then he expects that Japan will be in trouble. Since plastic molded lead frame packages represent 85% of electronic product applications, Japan's electronic industry must continue to lead in this area.
Japan will remain the leader in LSI packaging technologies.
Dr. Otsuka said that over 85% of electronic packaging uses plastic molded lead frame technologies. Because these packaging technologies are so pervasive in Japanese industry and because so many companies are committed to them, he argues that Japan will continue to dominate in low-cost packaging technology. LSI packaging technologies include materials, parts, subassemblies, and assembly process. Most companies have specialized in specific areas of plastic packaging technology, which provides Japan with the strongest low-cost packaging infrastructure. This infrastructure is distributed across both large and small companies in Japan and, because it is pervasive, is unlikely to change its technological direction. He pointed out that it would be virtually impossible for any one company or group to change the technological focus of this infrastructure. Dr. Otsuka argued that, as a result, the low-cost electronic packaging industry in Japan will continue to develop current plastic packaging technology, because it is the easiest direction for all industry participants to continue in.
Low cost is top priority in the Japanese industry, which requires mass production technologies.
Because of Japan's cost requirements, Dr. Otsuka argued that LSI plastic packaging technology has to utilize mass production technology. This mass production orientation will continue to utilize existing packaging technologies. New technologies will require new mass production technologies, which would be expensive to develop and lead to higher costs. To keep from incurring such added costs, Dr. Otsuka argued that companies will continue to push existing packaging technologies to their limits rather than add new high-cost technologies. This strategy means that Japanese companies seek to solve performance problems related to current plastic packaging technologies.
Current plastic molded package technologies will meet future miniaturization requirements.
Dr. Otsuka feels that QFP packages can be designed with 0.15 mm pin pitch. Such fine pitch will allow 800 pins on a 32 mm package, or 1000 pins on a 40 mm package, or 384 pins on a 16 mm package. To support his argument, Dr. Otsuka gave examples of developments that are currently under production or development in Japan. He provided an example of 344 pins on a 28 mm package using 0.3 mm pin pitch that is currently in production at Hitachi.
Dr. Otsuka argued that Japan's strength is due to the extensive infrastructure of companies involved in plastic electronic packaging technology. Japanese companies have developed QFP packages with 500 pins, available from Nippon Printing Company by 1996, using 0.3 mm pin pitch. Some firms are currently developing this process using 0.2 mm pin pitch chips. This will allow plastic QFP packages to surpass ceramic PGA packages in pin density. Such strong development power comes from Japan's massive investment in all areas of plastic packaging technology. Nikkei Electronics described these developments in its August 2, 1993 issue (p. 94).
Dr. Otsuka also described Kyushu Matsushita's 0.15 mm pitch soldering process that he expects to be commercialized within several years. This process uses a solder precoat (super solder) with the body being pushed down as infrared heat is applied. The company uses solder bumps to ensure contact, but staggers the bumps to minimize shorting. This process would not require new machine technology for production utilization. Kyushu Matsushita is planning to use this approach in its next-generation camcorder production. While it is currently using TAB technology, Dr. Otsuka believes that the approach will be used with SMT in the future. Hitachi is currently producing circuits with 90 micron wire bonding on chips with spaces between the wire of 120 microns. Oki and Nippon Steel have demonstrated wire bonding with 40 micron pitch. Dr. Otsuka believes that we will see this in production in the future.
Fine pitch requires materials with higher resistivity. Fine pitch creates additional soldering problems by causing high current on the printed circuit board. Dr. Otsuka suggested that new materials will be used on fine-pitch boards. For example, conventional FR-4 through-hole resistivity is too low at 130 degrees C to be used on fine-pitch boards. High Tg epoxy provides better resistivity, but for fine-pitch boards, the high resistivity requirements can be met with BT resin. Mitsubishi Gas Chemical has used BT resist (BTM 450) on contacts with 1.27 mm separation.
Japan will overcome low yield problems caused by fine pitch packages. Dr. Otsuka agreed that the move to fine pitch production will cause higher reject rates in the beginning. However, he argued that Japan has a long history of taking lower yield technology and improving it. In the United States, he believes that companies change technologies if they have low yields, but not in Japan. In addition, QFP is more inspectable than BGA even in low yield situations. Inspectability is very critical to ensuring quality products.
Finer pitch packages will automatically improve operating characteristics.
Fine pitch will increase product design flexibility. Since height is very important, single-layer boards are preferred in package design. Also, single boards are simpler to produce and are therefore cheaper to produce. Fine-pitch soldering would mean that we do not need two-layer bonding systems. Two-layer bonding has lower reliability because it depends on the solder connections. Simple packages are the best in every characteristic. For 0.3 mm pin pitch, a 40 sq. mm QFP package can have over 500 pins. With 0.2 mm pin pitch, 34 sq. mm packages can have 600 pins. At 0.15 mm pin pitch, we can have 600 pins on a 28 sq. mm package, comparable to a 1.0 mm pitch bump BGA chip. Dr. Otsuka used the previous examples to argue that these dense packages will be available within this decade.
Fine-pitch packages will provide additional advantages. Dr. Otsuka pointed out that finer pitch allows the use of three-set wiring design instead of two-set wiring between ground and power leads. Three-set wiring can increase output from 80-90 Ohms to 95-105 Ohms at 200 MHz and above. Finer pitch allows use of three-set packages for high-power packages. At the same time, impedance can be reduced once pin pitch falls below 0.3 mm. Japanese researchers have simulated 0.05 mm pin pitch designs and found that impedance drops 50%. Coupling capacitance can be further reduced in fine-pitch applications by using shorter wires. Shorter wires also means that multilayer wiring in single-chip packages is not essential. As long as power consumption stays below three watts per chip, chip scale packaging with short wires and fine-pitch provide the best design solutions. This has already been utilized in memory DRAM developments and should be viable in LSI packaging. As long as power consumption stays under 3 watts, natural cooling systems can be used and costs kept lower.
Dr. Otsuka also pointed out that reduced voltage requirements and reduced load capacitance can save power consumption (P=1/2*CV[sup]2). Lower voltage reduces coupling noise. He then argued that as we reduce package size, everything improves: "If we can communicate MHz at 3.3 volts, then the same package using 1.5 volts can operate at 400 MHz." He believes that QFP chip scale packages will be able to pass 200 MHz in the future.
QFP will be competitive with BGA on price-performance measures. Dr. Otsuka believes that QFP packages are better than BGA packages because they are inspectable and don't require new assembly technology. While the U.S. is interested in BGA because of its high pin count, Dr. Otsuka believes that 0.15 mm pin pitch on QFP packages will make them competitive with BGA alternatives. Since most Japanese companies do not have BGA capabilities, he expects continued QFP design and technology improvements to keep QFP packages cheaper than BGA packages.
Figure Meisei.1 shows the competitiveness of different packaging technologies, and additional insights offered by Dr. Otsuka are shown in Figure 4.5. Dr. Otsuka pointed out that ceramic substrates are cheaper in high-performance applications, but he believes that improvements described in the above statement will make QFP boards cost-competitive in future high-performance applications. The critical improvements are in the soldering process for wire bonding systems and in reducing popcorn problems of chips. If these problems can't be overcome, Japan will not be competitive in the future. But if Japanese firms can meet future miniaturization requirements with QFP technology, they will continue to be the low-cost producers of high-volume electronic packaging.
Figure Meisei.1. Competitiveness of different packaging technologies.
Dr. Otsuka believes single-chip packages will be cheaper than integrated chips on a substrate. He believes pushing the current technology to the limits will be cheaper than introducing new technology. Japan has alternative technologies, but low-cost plastic package technology is much cheaper. However, if package technology cannot achieve its improvement objectives, then its cost will cross over, and multichip technology will be cheaper.
Several technologies are unlikely to become dominant. Dr. Otsuka felt that adhesive conductors create too much noise and are too low in quality to replace solder connections. He continued to argue that the simple technology will survive. Reduction in size will reduce the problems of solder pollution and allow high-quality alternatives to be used. Because miniaturization will require less solder, it will be cost-effective.
Japanese companies guarantee everything about their products. Dr. Otsuka believes that they will continue to provide complete packages instead of bare chips. They want to control the assembly of their components to ensure their performance.
Cost is the First Objective
There are three strategic objectives in Japanese competitive strategy. Since the mid-1980s the acronym "QCD" has been pervasive among Japanese companies: it stands for quality, cost, delivery.
All Japanese electronics suppliers are forced by their customers to keep lowering their costs. At the lowest cost, the company that provides the highest quality with the best availability or delivery wins sales. This puts great pressure on firms to reduce costs and improve quality as a daily activity. It also makes it extremely difficult for Japanese suppliers to make a high profit.
Miniaturization is Driving Automation
Sony has been driving consumer products technological development in Japan since the mid- 1980s when it introduced the minicamcorder. It has set the rules of the game for development by projecting that the next model be half the size and half the cost for the same function. For example, its first minicam was 1.6 kg, its second was 0.8 kg, and the most recent was 0.4 kg. The current technology driver is the cellular telephone at 0.2 kg. These small-sized products are pushing product components and packaging technologies to smaller sizes.
Continued commitment to the miniaturization of products and component technologies requires increased investment in production technologies and factory automation. As part sizes shrink, human assembly is no longer feasible. This has pushed assembly technologies to become more precise and faster. For example, precision robots have improved repeatability precision from 0.05 mm to 0.01 mm since the mid-1980s. Matsushita's new SMT machine has 11 placement heads with 0.01 mm repeatability. Sony's high-speed robots are now working at 0.012 repeatability placement.
Miniaturization and Automation are Increasing Competitive Advantage
Japanese companies have been committed to miniaturization for nearly a decade. Product miniaturization is leading to improved product operating characteristics. Smaller component sizes lead to lower power usage and heat generation and longer battery life. Automation has led to improved quality and faster delivery of new products. Sony's factory automation activities have caused defect rates to drop to 20 ppm and have reduced ramp-up time to half that of manual assembly facilities. The goal of miniaturization has been supported by concurrent engineering in both product and process technology development. Companies have invested heavily in process technologies to achieve the miniaturization goals that can no longer be achieved through manual production techniques. By developing existing technologies rather than investing heavily in new technologies, they have been able to keep overall costs down and have stayed competitive in advanced consumer products.
High Technology is Only Used When Required
Japan's electronic packaging industry is heavily committed to plastic molded packaging systems. Cost as a competitive objective leads Japanese electronics suppliers to avoid high-technology solutions to their miniaturization problems. Current QFP packaging technologies are being pushed to their limits. Miniaturization of all components appears to be the strategy, not the movement to new technologies. New packaging technologies such as MCM are used when needed, but are considered higher-cost than established technologies. The miniaturization of current packaging technologies appears to be meeting the needs of most product requirements.
At the same time, high-technology packaging solutions are available in Japan in high-performance products such as supercomputers. A recent study of supercomputers found that Hitachi had the most advanced design for future MCM applications. This suggests that costs will limit the use of such technologies except where current technologies fail to meet the functional or size requirements of the package.
GROUP COMMENTS MADE DURING THE DISCUSSION AT NCR