Mitsubishi Denki Kabushiki Kaisha

Akira Kawai

Shinichi Sato

Hiroji Ozaki

Masao Nagatomo

Akira Tokui

Masayuki Nakajima

Shigeo Uoya

Alignment marks capable of providing accurate registration signals even if substrate surface is rough and capable of effectively preventing degradation of registration accuracy due to unevenness of a surface of a resist film, and method of forming such alignment marks are disclosed. The alignment marks include flat portions 1a having high vertical reflectance serving as the alignment mark portions and rough portions 1b, formed spaced apart from each other by a prescribed distance on a surface of a substrate 1 by irradiation of laser beam 50. Therefore, fluctuation of height of a surface of a resist film 13 formed on the alignment marks with an upper layer film posed therebetween can be prevented, and in turn, degradation of registration accuracy of masks due to the unevenness of the resist film surface can be effectively prevented. Even if the surface of the substrate is rough, flat portions 1a providing accurate signal waveforms can be easily formed.

Alignment mark having regions formed by energy beam irradiation therein

A method of applying a treatment liquid to a semiconductor wafer to form a coating include rotating a semiconductor wafer in its own plane within a hermetically-sealed container, discharging a cleaning fluid through a cleaning fluid nozzle onto the top surface of the wafer as it rotates, and then discharging a treatment liquid through a treatment liquid nozzle onto the center of the top surface of the wafer as it rotates. An apparatus for coating a treatment liquid on a semiconductor wafer comprises a hermetically-sealed container, a wafer chuck which rotates a semiconductor wafer in its own plane, a treatment liquid nozzle for connection to a supply of treatment liquid and discharging the treatment liquid onto the center of the top surface of the wafer as it rotates, and a cleaning fluid nozzle which is disposed to discharge a pressurized cleaning fluid onto the top surface of the wafer as it rotates.

Method for applying a treatment liquid on a semiconductor wafer

A semiconductor memory device in accordance with the present invention comprises: a semiconductor substrate (1) of a first conductivity type; a charge storage region (6) and a bit line region (7) of a second conductivity type formed on a main surface of the substrate; highly doped regions (12a, 12b) of the first conductivity type formed respectively contiguous to only the bottom boundaries of the charge storage region (6) and the bit line region (7).

Semiconductor memory device and fabricating method thereof

A semiconductor memory device comprises a first conductivity type semiconductor substrate (1) formed thereon with a charge storage region (5) and a second conductivity type region (6) serving as a bit line, and first conductivity type highly concentrated regions (8, 11) higher in concentration than the semiconductor substrate (1) at least by one digit are formed to enclose the charge storage region (5) and the bit line region (6) respectively. Thus, potential barriers against electrons can be defined in interfaces between the highly concentrated region (8) and the charge storage region (5) and between the highly concentrated region (11) and the bit line region (6), thereby to prevent malfunction caused by incidence of radioactive rays such as alpha rays.

Semiconductor memory device with deep bit-line channel stopper

The present invention is a method for fabricating a semiconductor device, wherein impurity is selectively diffused to surround a region (7) of a second conductivity type as a bit line formed on a semiconductor substrate (1), thereby forming an impurity diffused region (9) of a first conductivity type having high density and, by extending the impurity diffused region (9) in the element separating step to form a high density region of the first conductivity type having high density.

Growing community of inventors

Hyogo, Japan

Akira Kawai