United Microelectronics Corp.

Wei-Jyh Liu

Lien-Sheng Chung

Chih-Kung Huang

Chen-Hao Hwang

Chad-Yang Chen

A phase-shifting mask structure has a base plate, a pattern zone on the base plate and a peripheral region on the periphery of the base plate around the pattern zone. The peripheral region and the pattern zone further have a plurality of alignment-checking patterns and alignment slits. Each alignment-checking pattern has a first pattern of light-blocking thin films and a second pattern of light-penetrating thin films. Similarly, each alignment slit has a third pattern of light-blocking thin films and a fourth pattern of light-penetrating thin films. In this invention, absolute light-blocking thin films are used in the light-blocking portions of the alignment-checking pattern and the alignment slits instead of the semi-transparent thin films in a conventional system. Thus, alignment checking errors due to the distortion of fiducial marks are minimized, and mask layers are more precisely aligned.

Phase-shifting mask structure

The method for providing a cleaned doped polycrystalline silicon surface involves providing a polycrystalline silicon body. The body is uniformly doped with a phosphorous impurity from a phosphorous vapor source, such as phosphorous pentoxide. The silicon oxide surface layer is removed from the doped polycrystalline silicon surface formed during the doping with a hydrofluoric acid solution. An important cleaning step of the doped polycrystalline silicon surface is now accomplished with a basic solution of hydrogen peroxide. The highly dense integrated circuit device process can now proceed with any desired patterning of the polycrystalline body or layer without the yield problems of the past.

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Taipei, Taiwan

Wei-Jyh Liu