Tohru Kikuchi

New screen-printable polyimide for IC devices

In order to develop a screen-printable polyimide paste, the structures, properties, and ratios of three major paste components (filler, binder, and solvent) were studied, and a film-forming strategy was established. This strategy comprises a novel type of polyimide particle filler, which can be dissolved in the binder and the solvent under the curing condition. A screen-printable polyimide paste was developed using this strategy. This paste gives uniform film with better mechanical properties than conventional polyimide paste, which comprises an insoluble polyimide particle filler. The effect of the solubility parameter of the solvent on mask swelling and moisture resistance was also examined. It was also examined. It was found that a lactone with a solubility parameter value of 18 approximately 20 (MJ/m/sup 3/)/sup 1/2/ is suitable as a paste solvent. The paste affords uniform pinhole-free polyimide films with good mechanical properties. As the mask swelling is low, the lifetime of stencil is longer than that of conventional pastes. >

New polyimide for multi-chip module application

P-terphenyltetracarboxylic dianhydride (p-TPDA), which has a rodlike structure, has been developed as a raw material for polyimides in order to reduce the propagation delay time associated with polyimide packaging for multichip modules. The coefficient of thermal expansion (CTE) of the polyimides derived from p-TPDA is approximately 2*10/sup -6/. This is much lower than that of conventional polyimides derived from bisphenyltetracarboxylic dianhydride (BPDA), which have a CTE of 8*10/sup -6/ K/sup -1/. Another attribute that these polyimides have is low dielectric constant, with a typical value of about 2.9. As a result, this polyimide can give improved performance when used in multichip module applications.<<ETX>>

New Polyimide for Multi-Chip Module

Recently, the trend in mounting technology has been toward the multi-chip module owing to its larger mounting density. A demand for low thermal expansion coefficient polyimide and a low dielectric constant polyimide is growing rapidly in complying with this trend.