Plasma processing method, plasma etching method and manufacturing method of solid-state image sensor

• US 20050085087A1
• Filed: 08/24/2004
• Published: 04/21/2005
• Est. Priority Date: 08/25/2003
• Status: Abandoned Application

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation), Seiji Samukawa
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation), Seiji Samukawa
• Inventors: Samukawa, Seiji, Okigawa, Mitsuru
• Application Number:
  US10/924,263
• Publication Number:
  US 20050085087A1
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 27/14806 Structural or functional details thereof

Abstract

A method of plasma processing is offered to suppress generation of interface states, specifically to suppress increase in the dark current of a solid-state image sensor by reducing the interface states. An interlayer insulation film made of silicon nitride film is formed over a silicon substrate by plasma CVD, and a photoresist layer is selectively formed on the interlayer insulation film. Subsequent heating process makes a profile of the photoresist layer round. Next, the interlayer insulation film is plasma-etched using the photoresist layer as a mask and a fluorocarbon gas as an etching gas to form micro lenses. Pulse-time-modulated plasma method in which RF power is supplied intermittently is used to suppress increase in the interface states at silicon-silicon dioxide interface due to an influence of UV light generated in the plasma etching.

Claims

1. A method for a plasma processing, comprising:

providing a vacuum chamber;

introducing a gas comprising a fluorocarbon gas into the vacuum chamber; and

supplying intermittently an RF power for generating plasma to the vacuum chamber.

2. The method of claim 1, wherein the fluorocarbon gas is CF₄ gas, C₂F₄ gas, C₄F₈ gas, CF₃I gas or a mixture thereof.

3. The method of claim 1, further comprising introducing a silicon wafer on which a solid-state image sensor is formed into the vacuum chamber for the plasma processing.

4. The method of claim 2, further comprising introducing a silicon wafer on which a solid-state image sensor is formed into the vacuum chamber for the plasma processing.

5. A method for a plasma etching of an insulation film formed on a semiconductor wafer, comprising:

placing the semiconductor wafer in a vacuum chamber;

introducing an etching gas comprising a fluorocarbon gas into the vacuum chamber; and

supplying intermittently an RF power for generating plasma to the vacuum chamber.

6. The method of claim 5, wherein the fluorocarbon gas is CF₄ gas, C₂F₄ gas, C₄F₈ gas, CF₃I gas or a mixture thereof.

7. The method of claim 5, wherein the etching gas further comprises oxygen gas, and the fluorocarbon gas is CF₄ gas, C₂F₄ gas, C₄F₈ gas, CF₃I gas or a mixture thereof.

8. The method of claim 5, wherein the semiconductor wafer comprises a solid-state image sensor formed thereon.

9. The method of claim 6, wherein the semiconductor wafer comprises a solid-state image sensor formed thereon.

10. The method of claim 7, wherein the semiconductor wafer comprises a solid-state image sensor formed thereon.

11. A method of manufacturing a semiconductor device, comprising:

forming a solid-state image sensor on a surface of a semiconductor wafer;

forming an insulation film over the solid-state image sensor;

forming a patterned photoresist layer on the insulation film; and

plasma-etching the insulation film using the patterned photoresist layer as a mask to form a lens on the solid-state image sensor,

wherein the plasma-etching uses an etching gas comprising a fluorocarbon gas, and an RF power is supplied intermittently to generate plasma for the plasma-etching.

12. The method of claim 11, wherein the fluorocarbon gas is CF₄ gas, C₂F₄ gas, C₄F₈ gas, CF₃I gas or a mixture thereof.

13. The method of claim 11, wherein the etching gas further comprises oxygen gas, and the fluorocarbon gas is CF₄ gas, C₂F₄ gas, C₄F₈ gas, CF₃I gas or a mixture thereof.