Method of forming a thin film on surface of semiconductor substrate

• US 5,407,867 A
• Filed: 09/22/1992
• Issued: 04/18/1995
• Est. Priority Date: 05/12/1988
• Status: Expired due to Term

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Iwasaki, Masanobu, Tokui, Akira, Mitsui, Katsuyoshi, Itoh, Hiromi, Tsukamoto, Katsuhiro
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US07/948,528
• Time in Patent Office: 938 Days
• Field of Search: 437/225, 437/228, 437/235
• US Class Current: 438/694
• CPC Class Codes: C23C 14/022 by means of bombardment with energetic particles or radiation
• CPC Class Codes: C23C 14/568 Transferring the substrates through a series of coating stations C23C14/562 takes precedence
• CPC Class Codes: C23C 16/0236 by etching with a reactive gas
• CPC Class Codes: C23C 16/54 Apparatus specially adapted for continuous coating
• CPC Class Codes: Y10S 438/913 Diverse treatments performed in unitary chamber

Abstract

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°˜700° 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.

Claims

1. A method of removing a naturally grown oxide film and other contaminants on the surface of a semiconductor substrate and then forming a thin film on the cleaned surface, comprising the sequential steps of:

placing said semiconductor substrate in a pretreatment chamber;

introducing into said pretreatment chamber a reaction gas selected from the group consisting of chlorine gas and fluorine gas capable of reacting with said naturally grown oxide film and said other contaminants;

heating said semiconductor substrate at a temperature greater than 200° and

up to 700°

C.;

irradiating said reaction gas with light;

said light having a wavelength capable of performing a photochemical reaction of said naturally grown oxide film and other contaminants on the surface of said semiconductor substrate with the reaction gas introduced into said chamber at said temperature, while said semiconductor substrate is being heated;

moving said semiconductor substrate to a chamber for the formation of said thin film without exposing it to the air, after removing said naturally grown oxide film and other contaminants on the surface of said semiconductor substrate by said photochemical reaction; and

forming the thin film on the clean surface of said semiconductor substrate.

2. A method in accordance with claim 1, wherein the removal of said naturally grown oxide film and other contaminants on the surface of said semiconductor substrate and the formation of said thin film are performed in a single chamber by moving said substrate from a pretreatment portion to a thin film formation portion.

3. A method in accordance with claim 1, wherein the removal of said naturally grown oxide film and other contaminants on the surface of said semiconductor substrate is performed in a first chamber and the formation of said thin film is performed in a second chamber.

4. A method in accordance with claim 3, wherein said naturally grown oxide film and other contaminants on the surface of said semiconductor substrate are removed in said pretreatment chamber,

the semiconductor substrate is subsequently moved into a gas atmosphere which is controlled such that said naturally grown oxide film is not formed again, and

the semiconductor substrate is then moved into said chamber for the formation of said thin film to form said thin film.

5. A method in accordance with claim 1, wherein said light is ultra violet rays.

6. A method in accordance with claim 1, wherein a light source for irradiation of said light comprises a low pressure mercury lamp, a high pressure mercury lamp, a mercury-xenon lamp, an Argon arc lamp, or an excimer laser.

7. A method in accordance with claim 1, wherein the pressure of said reaction gas in said pretreatment chamber is selected in the range from atmospheric pressure to 0.1 Torr.

8. A method in accordance with claim 1, wherein said semiconductor substrate is heated at said temperature by irradiating said semiconductor substrate with light.

9. A method of removing a naturally grown oxide film and other contaminants on the surface of a semiconductor substrate and then forming a thin film on the cleaned surface, comprising the sequential steps of:

providing a first chamber for removing said naturally grown oxide film and other contaminants, a second chamber for forming said thin film, and a third chamber in which a gas atmosphere is controlled and provided between said first chamber and said second chamber,

placing said semiconductor substrate in said first chamber;

introducing into said first chamber a reaction gas capable of reacting with said naturally grown oxide film and said other contaminants;

removing said naturally grown oxide film and other contaminants on the surface of the semiconductor substrate by irradiating said reaction gas with light and heating said semiconductor substrate at a temperature within the range of 200°

-700°

C. in said first chamber;

moving said semiconductor substrate from said first chamber to said third chamber,

controlling the gas atmosphere in said third chamber such that said naturally grown oxide is not formed again on the semiconductor substrate,

moving said semiconductor substrate from said third chamber to said second chamber; and

forming the thin film on said cleaned surface of said semiconductor substrate in said second chamber.

10. A method of removing a naturally grown oxide film and other contaminants on the surface of a semiconductor substrate and then forming a thin film on the cleaned surface by sputtering, comprising the sequential steps of:

providing a chamber having a light source for irradiating a light into the chamber and a sputtering target placed in the chamber for providing components of the thin film;

placing said semiconductor substrate in said chamber such that the semiconductor substrate is opposite said light source;

introducing into said chamber a reaction gas capable of reacting with said naturally grown oxide film and said other contaminants;

removing said naturally grown oxide film and other contaminants on the surface of the semiconductor substrate by irradiating said reaction gas with light of said light source and heating said semiconductor substrate at a temperature within the range of 200°

-700°

C.;

moving said semiconductor substrate such that the semiconductor substrate is generally opposite said sputtering target; and

forming the thin film on the cleaned surface of said semiconductor substrate by sputtering said target.