Dry-etcching method

• US 20040192056A1
• Filed: 12/15/2003
• Published: 09/30/2004
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Yamada, Norikazu, Iijima, Etsuo
• Granted Patent: US 7,476,624 B2
• Time in Patent Office: Days
• US Class Current: 438/706
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01L 21/32137 of silicon-containing layers

Abstract

A main etching step is effected in a state shown in FIG. 1A under a first pressure using a gas containing at least HBr, e.g., a mixture gas of HBr and Cl₂ as an etching gas. The main etching is ended before a silicon oxide film 102, as shown in FIG. 1B, is exposed. An over-etching process is effected under a second pressure higher than the first pressure using a gas containing at least HBr, e.g., an HBr single gas so as to completely expose the silicon oxide film 102 as shown in FIG. 1C. In such a way, the selectivity of a silicon-containing conductive layer with respect to the silicon oxide film is improved compared to conventional methods. Without etching the silicon oxide film layer, which is an underlying layer, and without marring the shape of the silicon-containing conductive film layer formed by etching, only the desired silicon-containing conductive film layer is removed by etching reliably.

Claims

1. A dry etching method for etching a silicon-containing conductive film layer formed on a silicon oxide film layer through a mask layer having a predetermined pattern shape formed on the silicon-containing conductive film layer, the method comprising:

a main etching process for performing a plasma etching under a first pressure lower than 13 Pa; and

an overetching process for performing, after the main etching process, a plasma etching under a second pressure ranging from 13 Pa to 27 Pa, which is higher than that of the main etching process by an etching gas containing at least an HBr gas but not containing Cl₂.

2. The method of claim 1, wherein the silicon-containing conductive film layer is a polysilicon layer.

3. The method of claim 1, wherein the silicon-containing conductive film layer is a silicide layer.

4. The method of claim 1, wherein the silicon-containing conductive film layer is a polysilicon layer and a silicide layer deposited thereon.

5. The method of claim 1, wherein the etching gas in the overetching process is a mixture gas of HBr and O₂ or the HBr gas.

6. The method of claim 1, wherein the etching gas used in the main etching process is a mixture gas of HBr+Cl₂, HBr+Cl₂+O₂, Cl₂+O₂, or HBr+O₂, or the HBr gas.

9. The method of claim 1, wherein the main etching process is terminated before the silicon oxide film layer underlying the silicon-containing conductive film layer is exposed by detecting an etching state of the silicon-containing conductive film layer.

7. A dry etching method for etching a silicon-containing conductive film layer formed on a silicon oxide film layer through a mask layer having a predetermined pattern shape formed on the silicon-containing conductive film layer by an etching gas containing at least an HBr gas, the method comprising:

a main etching process for performing a plasma etching under a first pressure lower than 13 Pa; and

an overetching process for performing, after the main etching process, a plasma etching under a second pressure ranging from 13 Pa to 27 Pa, which is higher than that of the main etching process,

wherein the overetching process includes a first overetching process and a second overetching process following the first overetching process.

8. The method of claim 7, wherein a pressure in the second overetching process is set to be higher than that in the first overetching process.

10. (Cancelled)

11. (Cancelled)