Hitachi Chemical Co., Ltd. has acquired a basic patent for resist materials useful for manufacturing IC package substrates, etc.
The patent specifies the structure of photosensitive resin compositions in a resist material and parameters such as the film thickness and aspect ratio (ratio of line width to film thickness) of the resist patterns formed by the material.
As a manufacturer of resist materials, or photosentive dry films PHOTEC, Hitachi Chemical has developed a series of resist materials.
Package substrates are now manufactured with an etching or plating method (semi-additive method in particular). In the future, however, the "semi-additive method," which is more favorable to finer wiring, is expected to prevail.
Hitachi Chemical's new patent regards a "semi-additive method," manufacturing process that uses photosensitive film to form resist patterns on a substrate and produces copper wiring through electrolytic plating.
It is regarded as one of the most vital technological features to form resist patterns with high aspect ratios in order to block, whenever possible, the reduction of wiring cross-sections that could lead to increasing electrical resistance.
Hitachi Chemical aims to build a patent network for the resist materials used in the process that forms wiring on IC package substrates, with the expectation that the patent the company has just acquired will play a key role in the network.