Process for producing semiconductor device, apparatus for optimizing film thickness, and process for optimizing film thickness

• US 6,218,313 B1
• Filed: 08/28/1998
• Issued: 04/17/2001
• Est. Priority Date: 08/29/1997
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kagotani, Hiroshi, Tomita, Manabu
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): ROCCHEGIANI, RENZO
• Application Number:
  US09/143,534
• Time in Patent Office: 963 Days
• Field of Search: 438/7, 438/16, 438/636, 438/427, 438/758
• US Class Current: 438/758
• CPC Class Codes: G03F 7/091 characterised by antireflection means or light filtering or absorbing means, e.g. anti-halation, contrast enhancement
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/31144 using masks

Abstract

A process for producing a semiconductor device and an apparatus and a process for obtaining an optimum film thickness, the process for producing a semiconductor device comprising forming a film of a light reflecting material on a semiconductor substrate; coating a positive resist on the film of a light reflecting material; forming a resist pattern from the positive resist; and etching the film of a light reflecting material using the resist pattern as a mask, wherein simulation of light intensity is conducted by using optical constants of the semiconductor substrate, the film of a light reflecting material and the resist obtained by measuring the optical constants thereof, or when optical constants thereof are known, by using the known optical constants, with varying a film thickness of the film of a light reflecting material to plural values, so as to obtain a film thickness of the film of a light reflecting material that makes a light absorption energy at an interface between the film of a light reflecting material and the resist minimum; and the film thickness of the film of a light reflecting material is set to the film thickness thus-obtained.

Claims

1. A process for producing a semiconductor device, comprising the steps of:

conducting a computerized simulation of light intensity using optical constants of a semiconductor substrate, a film of a light reflecting material, and a positive resist, while inputting a plurality of values for film thicknesses of said film of a light reflecting material, to determine an optimal thickness of said film of a light reflecting material that corresponds to a minimum absorption energy at an interface between said film of a light reflecting material and said resist;

forming said film of a light reflecting material at said optimal thickness on said semiconductor substrate;

coating said positive resist on said film of a light reflecting material;

forming a resist pattern from said positive resist; and

etching said film of a light reflecting material using said resist pattern as a mask,

wherein said optical constants of said semiconductor substrate, said film of a light reflecting material and said resist are obtained by measuring said optical constants thereof, or when optical constants thereof are known, by using said known optical constants.

2. A process for producing a semiconductor device, comprising the steps of:

conducting a computerized simulation of light intensity using optical constants of a semiconductor substrate, a film of a light reflecting material, and a positive resist, while inputting a plurality of values for film thicknesses of said film of a light reflecting material, to determine an optimal thickness of said film of a light reflecting material that corresponds to a maximum absorption energy at an interface between said film of a light reflecting material and said resist;

forming said film of a light reflecting material at said optimal thickness on said semiconductor substrate;

coating said positive resist on said film of a light reflecting material;

forming a resist pattern from said positive resist; and

etching said film of a light reflecting material using said resist pattern as a mask,

wherein said optical constants of said semiconductor substrate, said film of a light reflecting material and said resist are obtained by measuring said optical constants thereof, or when optical constants thereof are known, by using said known optical constants.

3. A process for producing a semiconductor device, comprising the steps of:

conducting a computerized simulation of light intensity using optical constants of a semiconductor substrate, a film of a light reflecting material, and a positive resist, while inputting a plurality of values for film thicknesses of said film of a light reflecting material;

conducting a computerized simulation of development using a result of said computerized simulation of light intensity to determine an optimal thickness of said film of a light reflecting material, at which a line width of said positive resist at an interface between said film of a light reflecting material and said resist is a median of a minimum value and a maximum value;

forming said film of a light reflecting material at said optimal thickness on said semiconductor substrate;

coating said positive resist on said film of a light reflecting material;

forming a resist pattern from said positive resist; and

etching said film of a light reflecting material using said resist pattern as a mask,

wherein said optical constants of said semiconductor substrate, said film of a light reflecting material and said resist are obtained by measuring said optical constants thereof, or when optical constants thereof are known, by using said known optical constants.

4. A process for optimizing a film thickness, comprising the steps of:

measuring optical constants of a semiconductor substrate, a film of a light reflecting material formed on said semiconductor substrate and a resist coated on said film of a light reflecting material;

conducting simulation of light intensity using said optical constants obtained, while varying a film thickness of said film of a light reflecting material to plural values; and

obtaining an optimum film thickness of said film of a light reflecting material from a result of said simulation of light intensity.

5. A process for optimizing a film thickness, comprising the steps of:

measuring optical constants of a semiconductor substrate, a film of a light reflecting material formed on said semiconductor substrate and a resist coated on said film of a light reflecting material;

conducting simulation of light intensity using said optical constants obtained, while varying a film thickness of said film of a light reflecting material to plural values;

conducting simulation of development using a result of said simulation of light intensity; and

obtaining an optimum film thickness of said film of a light reflecting material from a result of said simulation of development.