Mitsubishi Denki Kabushiki Kaisha

Akira Tokui

Katsuhiro Tsukamoto

Shinichi Sato

Hiroji Ozaki

Masao Nagatomo

Hiromi Itoh

Masanobu Iwasaki

Masayuki Nakajima

Akira Kawai

Katsuyoshi Mitsui

Masahiro Yoneda

Tetsuro Hanawa

Maria O DeBeeck

The present invention provides a method for removing a natural gas film or contaminant adhering on a surface of a silicon semiconductor substrate. The semiconductor substrate having the natural oxide film or contaminant adhered thereon is placed in a chamber. Then, a HCl gas is introduced into the chamber. The semiconductor substrate is heated at a temperature in the range of 200.degree..about.700.degree. C., while ultraviolet rays are irradiated into the chamber. According to the method, the reaction of the natural oxide with HCl gas is promoted by a synergistic effect of light and heat energy. Therefore, the natural oxide film or contaminant can be removed at a lower temperature with the help of the light energy.

Method for pretreating semiconductor substrate by photochemically

A method of and an apparatus for removing a naturally grown oxide film and contaminants on the surface of a semiconductor substrate and then forming a thin film on the cleaned surface. The semiconductor substrate is placed in a pretreatment chamber and then hydrogen chloride gas is introduced into the chamber. Then, the semiconductor substrate is heated at a temperature between 200.degree..about.700.degree. C. and the surface of the semiconductor substrate is irradiated with ultraviolet rays, whereby the naturally grown oxide film and other contaminants on the semiconductor substrate can be removed. Then, a thin film is formed on the cleaned surface of the semiconductor substrate by a CVD method or a sputter method. According to this method, the naturally oxide film and other contaminants can be removed from the surface of the semiconductor substrate at a low temperature and the thin film can be formed on the cleaned surface. As a result, an interface structure between the semiconductor substrate and the thin film can be controlled to be in a preferable state.

Method of forming a thin film on surface of semiconductor substrate

A photomask for projecting a transfer pattern onto a wafer having a plurality of regions with different surface levels includes a transparent substrate; a shielding member on the transparent substrate having a plurality of patterns for projection onto respective regions of the wafer; and an optical-path-length varying layer on at least one of the patterns corresponding to a region of the wafer other than a reference region of the wafer for changing the optical path length of light transmitted through the pattern by a length corresponding to the difference in surface level between the corresponding region and the reference region of the wafer. A pattern transfer method using such a photomask includes directing light onto the photomask; effecting a change in the position of the apparent object-side image surface for at least one pattern including the optical-path-length varying layer; and simultaneously forming on surfaces of the wafer regions image formation planes respectively corresponding to at least two patterns by image projection using light transmitted through the patterns.

Photomask and pattern transfer method for transferring a pattern onto a

An apparatus for inspecting a phase shift mask includes a light source for irradiating a pattern of a phase shift mask including a light shield member and a phase member, a phase difference detector for generating from light transmitted through the phase shift mask a phase signal including the phase difference created by the phase member, a reference signal generator for generating a reference signal, and a calculation section for detecting a defect in the phase member of the phase shift mask by comparing the phase signal with the reference signal. The reference signal may be generated from a reference mask having the same pattern as that of the phase shift pattern or from CAD data for the formation of the pattern of the phase shift mask.

Apparatus for inspecting a phase shift mask

A method of forming a minute pattern with controlled resist profile by using chemically amplifying type resist and deep UV ray is disclosed. A positive chemically amplifying type resist is applied on a silicon substrate, to form a resist film of the resist on the silicon substrate. The resist film is selectively irradiated with KrF excimer laser beam by using a photomask. Thereafter, an electric field directed vertically downward is applied to the resist film while the resist film is heated. According to this method, H.sup.+ ions which are catalyst for destroying the dissolution inhibiting capability of the dissolution inhibitor generated in the resist film move vertically downward, so that diffusion of the H.sup.+ ions in the lateral direction during heating can be prevented. Consequently, a positive minute pattern having sidewall formed vertical to the substrate can be provided.

Method of forming minute patterns using positive chemically amplifying

A method and apparatus for manufacturing a semiconductor device having a thin layer of material formed on a semiconductor substrate with a much improved interface between them are disclosed. A silicon substrate is heated up to a temperature around 300.degree. C. in the presence of ozone gas under exposure to UV light. Through this process, organic contaminants that might be present on the surface of the silicon substrate are dissipated by oxidation, and a thin oxide film is formed on the substrate surface on the other. The silicon substrate with the thin oxide film coated thereon is then heated up to temperatures of 200.degree.-700.degree. C. in the presence of HCl gas under illumination to UV light to strip the oxide film off the substrate surface, thereby exposing the cleaned substrate surface. Finally, HCl cleaned surface of the silicon substrate is coated with a thin layer of material such as monocrystalline silicon without exposing the cleaned substrate surface. The method provides a semiconductor with the thin layer of material formed thereon having a well-controlled, well organized interface between them.

Method for forming a thin layer on a semiconductor substrate and

Apparatus for forming a thin film on surface of semiconductor substrate

A method of forming a minute pattern with controlled resist profile uses a chemically amplifying type resist and deep UV rays. Microposit SAL601-ER7 is applied on a silicon substrate, to form a resist film of the resist on the silicon substrate. The resist film is selectively irradiated with KrF excimer laser beam by using a photomask. Thereafter, an electric field directed vertically downward is applied to the resist film while the resist film is heated. According to this method, H.sup.+ ions which are a catalyst for cross linking generated in the resist film move vertically downward, so that diffusion of the H.sup.+ ions in the lateral direction during heating can be prevented. Consequently, negative minute patterns having sidewalls formed vertical to the substrate can be provided.

Method of forming minute patterns using chemically amplifying type resist

A method and apparatus for manufacturing a semiconductor device having a thin layer of material formed on a semiconductor substrate with a much improved interface between them are disclosed. A silicon substrate is heated up to a temperature around 300.degree. C. in the presence of ozone gas under exposure to UV light. Through this process, organic contaminants that might be present on the surface of the silicon substrate are dissipated by oxidation, and a thin oxide film is formed on the substrate surface on the other. The silicon substrate with the thin oxide film coated thereon is then heated up to temperature of 200.degree.-700.degree. C. in the presence of HCl gas under illumination to UV light to strip the oxide film off the substrate surface, thereby exposing the cleaned substrate surface. Finally, HCl cleaned surface of the silicon substrate is coated with a thin layer of material such as monocrystalline silicon without exposing the cleaned substrate surface. The method provides a semiconductor device with the thin layer of material formed thereon having a well-controlled, well-organized interface between them.

Method for forming a thin layer on a semiconductor substrate

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 Tokui