Noritaka Oyama

Unique white LED packaging systems

Recently, many engineers are developing White LED in the world. LED Packaging is used normal transparent epoxy resin. But White LED is occurring a few W light kom Blue LED element itself. Normal transparent epoxy resin discolors by this W light fiom Blue LED element. And it is difkult to preserve for long time White color after packaging. General packaging method is used casting molding method. This method can’t product high density, light weight packaging. The fmt time, we developed special transparent epoxy resin to preserve White LED by improving epoxy chemical structure. We get very good result after humidity evaluation(60”C /85%/300hrs/20mA). Normal transparent epoxy resin discolors after this evaluation condition. Secondly, we developed high-density packaging technology using VPESTM (Vacuum Printing Encapsulation Systems). These good advantages are very fme pitch and low height, high-density packaging technology, good mass production, and low wst systems. We successes very high density and high reliabiliry White LED packaging using high level of transparent epoxy resin and VPESTM technology. Our White LED can use as lighting application instead of fluorescent lamp and general lighting and traffic signal. And this light is very good for environmental conservation in the

New packaging of a chip on a board by a unique printing method

Transfer molding is a typical method for packaging integrated circuits (ICs). Transfer molding is very difficult to do at heights less than 1 mm, and has a limited surface mounting area. Recent research of high density surface mounting for thinner and lighter weight packaging has progressed for both IC cards and liquid crystal displays (LCDs). However, the dispensing method has many problems, such as the height variations of the coating, difficulties of uniform spreading on large size ICs, and one-by-one encapsulation. A unique printing method is developed to solve such problems. Through this method it is possible to achieve a height less than 1 mm and a uniform thickness on an integrated system. On reaching these parameters, the surface mount ICs replace molded packaged devices that are manufactured using expensive equipment and molding dies. The method requires only a small amount of epoxy resin and is, therefore, more economical than the conventional transfer molding process. A one-component epoxy resin NPR-150 suitable for printing is developed. >

New packaging of chip-on-board by unique printing method

A novel printing method which has been found to be successful in making the chip-on-board (COB) packaging for ICs has been developed. Using this technique, it has become possible to achieve less than mm height, uniform thickness, and all-in-one operation. This method is more economical than the transfer-molding method. In addition, the cost of packages is much reduced, and it is more suited to mass production. One-component epoxy-resin, called NPR-150, has been developed which is suitable for printing. Deformation of gold wires was not observed, and reliability test results showed excellent levels, comparable to the formal transfer-molding packaging.<<ETX>>

Printing encapsulation systems (PES) of advanced multichip module and COB device

Continuous study of a printing encapsulation system (PES) for multichip module and COB (chip on board) led to optimal encapsulation resin properties. The authors have developed a printing encapsulation system (PES) of high reliability and quality, free of voids, and a thin and desirable encapsulation resin shape for an advanced COB device. Using this PES, it was possible to solve the problems in the printing encapsulation process to keep control of resin viscosity and other properties at open lid storage. It was possible to determine the suitable thixotropic property index. The authors developed a void-free process system which avoids the effects of heat shock and achieves moisture resistance improvement, and a short time curing system.<<ETX>>

High reliability MCM packaging using low stress liquid type epoxy resin by printing encapsulation systems (PES)

MCM/sup L/ can expect to be the main current of semiconductor packaging technology in near future. BGA, PLCC and PGA packaging methods will expect much of this application. But the most pressing problem is warp after the packaging process. The warp after packaging needs to be below 150 /spl mu/m at BGA and 100 /spl mu/m at PLCC. We have already developed the Printing Encapsulation Systems (PES). PES is able to make low cost and mass produced semiconductor packaging. This paper describes the use of PES to make MCM/sup L/ semiconductor packaging. We have developed a low warp packaging epoxy resin using elastomer modified epoxy resin to fit BGA, PLCC and PGA. We verified the low stress epoxy resin using dynamic mechanical properties and internal stress measurements. We packaged BGA, PLCC and BGA with this low stress epoxy resin using PES, and measured the warp of each packaging. We obtained good results for the warp, demonstrating that using this low stress epoxy resin and PES, low cost and high reliability packaging of BGA, PLCC and PGA could be achieved.<<ETX>>

New metal board for COB, Multi-Chip Module, TAB and Phlip-Chip

Recently, the use of high-density mounting and multi-function design have been rapidly progressing on the industry. For metal board, the chip on board (COB) method has been widely employed with which a silicon chip is directly connected to a metal board by use of the wire bonding method. However, conventional metal boards are insufficient with respect to reliability. We have succeeded in the development of metal board having a high reliability by using a compound material high-purity, of a high-function naphthalene epoxy resin and an aramid paper from PPODTA (Co-poly-paraphenylene 3,4-oxydiphenylene terephthalamide) for its insulating layer which is the most important part with respect to reliability. The metal board is excellent in heat resistance and heat dissipation, and particularly in migration resistance. Its coefficient of linear expansion is 6 ppm board can be expected to be applied for advanced surface mounting technologies, such as LCCC, COB, Flip Chip, PGA, MCM (Multi Chip Module) and TAB. These applications are automobiles, air conditioners, air craft, space satellite, rocket and small-sized motors.<<ETX>>