Method for forming a semiconductor device in which an anti reflective layer is formed by varying the composition thereof

• US 5,674,356 A
• Filed: 04/04/1995
• Issued: 10/07/1997
• Est. Priority Date: 04/05/1994
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nagayama, Tetsuji
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): ALANKO, ANITA KAREN
• Application Number:
  US08/416,218
• Time in Patent Office: 917 Days
• Field of Search: 156/659.11, 156/661.11, 430/316, 430/950
• US Class Current: 438/694
• 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 21/0276 using an anti-reflective coating anti-reflective coating for lithography in general G03F7/09
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: Y10S 430/151 Matting or other surface reflectivity altering material
• CPC Class Codes: Y10S 438/952 Utilizing antireflective layer

Abstract

A method for producing a semiconductor device in which dry etching properties are rendered compatible with satisfactory anti-reflection characteristics in far-infrared lithography. An anti-reflective layer 6 is made up of a lower anti-reflective layer 6_L of SiO_X having a relatively low Si ratio and an upper anti-reflective layer 6_H of SiO_X having a relatively high Si ratio. After forming a resist pattern 7, the upper anti-reflective layer 6_H and the lower anti-reflective layer 6_U are etched using the etching conditions for Si and those for SiO_X, respectively. Such variation in the Si ratio along the film thickness is realized by controlling the CVD film-forming conditions or Si⁺ ion implantation. Since the upper anti-reflective layer 6_H has a refractive index higher than that of the lower anti-reflective layer 6_L of SiO_X, the standing wave suppression effect is improved. Since the films 6_U, 6_L are etched under respective optimum conditions, shape anisotropy may be realized. Film formation is not difficult to achieve because the elementary composition of the anti-reflective layer 6 on the whole is uniform.

Claims

1. A method for producing a semiconductor device comprising:

providing an anti-reflective layer presenting a variation in the composition of a constituent element along the film thickness over a semiconductor substrate, said anti-reflective layer being formed by a vapor phase deposition method and the variation in the composition being achieved by controlling the film forming atmosphere, the anti-reflective layer having a silicone-rich upper layer portion;

forming a pattern resist on said anti-reflective layer; and

dry-etching said anti-reflective layer under etching conditions conforming to the variation of the composition, using said pattern resist as a mask.

3. The method as claimed in claim 1 or 2 wherein the anti-reflective layer has a composition so selected that its upper layer portion has a refractive index higher than that of its lower layer portion.

4. The method as claimed in claim 1 or 2 wherein the anti-reflective layer is a film formed of a silicon compound and having a composition with a variable silicon ratio.

5. The method as claimed in claim 1 or 2 wherein the anti-reflective layer is a film of a silicon compound selected from the group consisting of SiO_X, SiN_x and Si_x O_y N_z.

6. The method as claimed in claim 1 or 2 wherein the anti-reflective layer is a film having a low refractive index area and a high refractive index area formed on the low refractive index area, said higher refractive index area having a refractive index higher than that of the resist film.

2. A method for producing a semiconductor device comprising:

providing an anti-reflective layer presenting a variation in composition of a constituent element along the film thickness over a semiconductor substrate, said anti-reflective layer being formed by a vapor phase deposition method and the variation of the composition being achieved by controlling the film forming atmosphere, the anti-reflective layer being a film formed of a silicon compound and having a silicon ratio in the composition thereof which increases proceeding from its lower layer portion towards its upper layer portion;

forming a pattern resist on said anti-reflective layer; and

dry-etching said anti-reflective layer under conditions conforming to the variation in the composition, using said pattern resist as a mask.

7. A method for producing a semiconductor device comprising:

providing an anti-reflective layer presenting a variation in the composition of a constituent element along the film thickness over a semiconductor substrate, said variation in the constituent element being provided by an ion implantation on a previously formed ant-reflective layer, the anti-reflective layer having a composition so selected that its upper layer portion has a refractive index that is higher than that of its lower layer portion;

forming a pattern resist on said anti-reflective layer;

dry-etching said anti-reflective layer under etching conditions conforming to the variation in composition, using said pattern resist as a mask.

8. The method as claimed in claim 7, wherein the anti-reflective layer is a film formed of a silicon compound having the same elements but having a composition with a variable silicon ratio.

11. The method as claimed in claim 7 or 9 wherein the anti-reflective layer is a film of silicon compound having the formula Si_x O_y N_z.

12. The method as claimed in claim 7 wherein the anti-reflective layer is a film having a low refractive index area and a high refractive index area formed on the low refractive index area, said higher refractive index area having a refractive index higher than that of the resist film.

9. A method for producing a semiconductor device comprising:

providing an anti-reflective layer presenting a variation in the composition of a constituent element along the film thickness over a semiconductor substrate said variation in the constituent element being provided by an ion implantation on a previously formed anti-reflective layer, the anti-reflective layer having a silicon-rich upper layer portion;

forming a pattern resist on said anti-reflective layer;

dry-etching said anti-reflective layer under etching conditions conforming to the variation in composition using said pattern resist as a mask.

10. The method as claimed in claim 9 wherein the anti-reflective layer is a film formed of a silicon compound and having a silicon ratio in the composition thereof increased from its lower layer portion towards its upper layer portion.