Hoya Corporation

Shigekazu Matsui

Masao Ushida

Masaru Mitsui

Takashi Fushie

Kouichi Maruyama

Takeshi Kagatsume

Kenichi Kagaya

Osamu Nagarekawa

A multilayer printed wiring board which permits the formation of fine wiring patterns, thereby increasing the density of wiring patterns. Using photosensitive glass having a coefficient of thermal expansion close to that of a copper film as a core substrate, a through hole is formed in the photosensitive glass by photolithography, a sputtering silicon oxide layer and a sputtering silicon nitride layer are formed to prevent leak of alkali metal ions from the photosensitive glass, a sputtering chromium layer, a sputtering chromium-copper layer and a sputtering copper layer are formed to enhance the adhesion strength between the copper film and the sputtering silicon oxide layer, and a copper film of 1 to 20 &#x3bc;m thick is formed. With resin filled into the interior of the through hole, a wiring layer is patterned by etching, an insulating layer is formed, and the surface is covered with a surface treatment layer and a cover coat.

Multilayer printed wiring board and a process of producing same

Photomask blank

A multilayer printed wiring board which permits the formation of fine wiring patterns, thereby increasing the density of wiring patterns. Using photosensitive glass having a coefficient of thermal expansion close to that of a copper film as a core substrate, a through hole is formed in the photosensitive glass by photolithography, a sputtering silicon oxide layer and a sputtering silicon nitride layer are formed to prevent leak of alkali metal ions from the photosensitive glass, a sputtering chromium layer, a sputtering chromium-copper layer and a sputtering copper layer are formed to enhance the adhesion strength between the copper film and the sputtering silicon oxide layer, and a copper film of 1 to 20 &mgr;m thick is formed. With resin filled into the interior of the through hole, a wiring layer is patterned by etching, an insulating layer is formed, and the surface is covered with a surface treatment layer and a cover coat.

Multilayer printed circuit board and the manufacturing method

In a photo-mask blank comprising a transparent substrate member and a shading layer of chromium covered on a principal surface of the substrate member, the shading layer has a first portion adjacent the principal surface and etched at a first etch rate and a second portion farther from the principal surface than the first portion and etched at a second etch rate lower than the first etch rate. For this purpose, nitrogen is dispersed so that the first portion becomes rich in nitrogen as compared with the second portion. Alternatively, carbon is dispersed so that the first portion becomes scarce in carbon relative to the second portion. The first portion may include nitrogen. The substrate member may comprise a transparent flat plate and a transparent conductive layer coated on the flat plate. The photo-mask blank is processed into a photo-mask through an etching process.

Photo-mask blank comprising a shading layer having a variable etch rate

Growing community of inventors

Nirasaki, Japan

Shigekazu Matsui