Sumitomo Metal Industries, Inc.

Sumitomo Metal Ceramics Inc.

Narumi China Corporation

Koichi Uno

Yasuo Nakatsuka

Yoshiaki Yamade

Yoichi Moriya

Yoshikazu Nakata

Shinichi Murakami

Akira Sanjyou

Kazunari Tanaka

Syozo Otomo

Yasuyuki Morita

A process for forming fine thick-film conductor patterns on a ceramic substrate which comprises the steps of forming grooves in a positive-working photoresist layer on the substrate by the photolithographic technology, filling the grooves with a conductive paste by squeezing with a squeegee, removing the photoresist layer by a wet process, and firing the remaining conductive paste pattern is improved. By the improvements, the conductive paste is squeezed into the grooves by the screen printing technique using a mask, and/or the solvent in the conducive paste consists essentially of one or more hydrocarbons, and/or the squeegee is made of a material having a flexural modulus in a range of 30-200 kgf/mm.sup.2. The formation of the grooves may be accomplished by laser beam machining; in this case a negative-working photoresist or any other soluble resin may be used to form the grooves therein. Also provided are a process for forming a fine thick-film conductor pattern by means of transfer of a conductive paste pattern formed on a support film to a green sheet, as well as a process for forming bumps on a ceramic circuit substrate.

Process for forming fine thick-film conductor patterns

Low-firing glass ceramic green sheets useful in the production of glass ceramic multilayer substrates are prepared from a coarse raw powder material comprising a B.sub.2 O.sub.3 -containing glass powder. The coarse raw powder material is initially subjected to wet grinding, either in an alcohol-free organic solvent in the presence or absence of an organic binder, or in an alcohol-containing organic solvent in the presence of an organic binder, until the powder is comminuted to a particle size suitable for tape casting. The wet-ground powder is slurried with an organic solvent and an organic binder, and the slurry is cast into sheets. The resulting green sheets have improved elongation and can be punched to form fine through holes with a small pitch.

Process for preparing glass ceramic green sheets

A ceramic substrate has a five-layered thin metallic film thereon. The first layer is Ti, Zr, Cr and/or W; the second layer is Ni and/or Mo; the third layer is one or more metals of group Ib in the periodic table; the fourth layer contains the same metals as the second layer and the fifth layer contains the same metals as the third layer.

Ceramic substrate having a multilayered metallic thin film

A hermetic cap member of a casing for a semiconductor memory element is provided with a protection layer on a recessed surface facing the memory element. The protection layer is of at least one material which does not emit alpha particles and has a thickness sufficient to prevent alpha particles from being emitted from the cap member onto the memory element. Specifically, the protection layer may be a plate of a pertinent one of the following silicon of high purity, 42 alloy, or Kovar and is attached to the cap member by the use of an adhesive of glass frit. Alternatively, the protection layer may be made from a metallic paste of silver, silver-palladium, or gold-palladium by firing the same onto the cap member. The protection layer may also be magnesium oxide formed by the use of a plasma spray process. As a further alternative, the protection layer may consist of a plurality of materials.

Casing having a layer for protecting a semiconductor memory to be sealed

Growing community of inventors

Nagoya, Japan

Koichi Uno