Mitsubishi Denki Kabushiki Kaisha

Ichiro Arimoto

Ritsuko Tsutsumi

Masami Yamamoto

Tomoharu Mametani

Eiichi Ishikawa

Junichi Kanbe

A level F.sub.A at a shot center of a specified shot is measured. A level F.sub.B is measured at a nonexposure region. A level difference .DELTA.F is calculated based on the level F.sub.A at the shot center and the level F.sub.B at the nonexposure region. After the level difference .DELTA.F is calculated for all the specified shots, an average value .DELTA.F.sub.ave of level differences .DELTA.F is calculated. Thereafter, focusing based on the average value .DELTA.F.sub.ave and subsequent exposure are executed for the respective shots in a step-and-repeat manner. Thereby, a focusing method in photolithography enables formation of elements having good pattern configuration even if the pattern is miniaturized to a higher extent in accordance with high integration.

Focusing method in photolithography

A LOCOS isolation film is formed on a major surface of a semiconductor substrate. Thereafter, a new surface of the semiconductor substrate is exposed by wet etching. A resist pattern is formed on the exposed new surface. A part of the LOCOS isolation film is removed using this resist pattern, to expose the surface of the semiconductor substrate. This unsymmetrical LOCOS isolation film increases the effective area of the surface of the semiconductor substrate and preserves predetermined dielectric resistance.

LOCOS type field isolating film and semiconductor memory device formed

Locos type field isolating film and semiconductor memory device formed

Growing community of inventors

Hyogo, Japan

Ichiro Arimoto