Etching method and plasma processing apparatus

• US 10,665,516 B2
• Filed: 08/30/2017
• Issued: 05/26/2020
• Est. Priority Date: 03/17/2017
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Matsui, Miyako, Kuwahara, Kenichi, Yasui, Naoki, Izawa, Masaru, Usui, Tatehito, Ohmori, Takeshi
• Primary Examiner(s): Duclair, Stephanie P
• Application Number:
  US15/690,660
• Publication Number:
  US 20180269118A1
• Time in Patent Office: 1,000 Days
• Field of Search: None
• CPC Class Codes: G01B 11/0625 with measurement of absorption or reflection
• CPC Class Codes: G01B 11/0675 using interferometry
• CPC Class Codes: H01J 2237/006 Details of gas supplies, e.g. in an ion source, to a beam line, to a specimen or to a workpiece, H01J37/3244 takes precedence; environmental cells for electron microscopes H01J2237/2003; microscopes with environmental specimen chamber H01J2237/2608
• CPC Class Codes: H01J 2237/3347 bottom of holes or trenches
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: H01L 21/306 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/31
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31122 of layers not containing Si, e.g. PZT, Al2O3
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/32135 by vapour etching only
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

The present invention relates to an etching method including a reaction layer forming step of forming a reaction layer by adsorption of a gas on a surface of an etching target material, a desorption step of desorbing the reaction layer after the reaction layer forming step, and a removal step of removing the reaction layer or a deposited film, characterized in that the surface of the etching target material is etched by the reaction layer forming step and the desorption step.

Claims

1. An etching method comprising:

a reaction layer forming step of forming a reaction layer by adsorption of a gas on a surface of an etching target material;

a desorption step of desorbing the reaction layer after the reaction layer forming step;

monitoring a thickness of the formed reaction layer; and

when the thickness of the formed reaction layer is greater than a predetermined amount, performing a removal step of removing the reaction layer remaining after the desorption step until a thickness of the formed reaction layer is within said predetermined amount,

wherein the surface of the etching target material is etched by the reaction layer forming step and the desorption step.

2. The etching method according to claim 1, wherein the monitoring a thickness is performed by an optical method.

3. The etching method according to claim 1, wherein

the reaction layer forming step, the desorption step, and the removing step are all performed using plasma, and

radio frequency power supplied to a sample stage on which a sample containing the etching target material is placed in the removal step is smaller than radio frequency power supplied to the sample stage in the desorption step.

4. The etching method according to claim 3, wherein a gas used in the removal step is different from a gas used in the desorption step.

5. The etching method according to claim 1,

wherein said thickness is one or more of a thickness between opposing sides of an opening in at least one mask, a thickness of the formed reaction layer on said at least one mask, and a thickness of said formed reaction layer on said etching target material, and

wherein said removal step comprises removing the reaction layer remaining after the desorption step until one or more of said thickness between opposing sides of an opening in at least one mask, said thickness of the formed reaction layer on said at least one mask, and said thickness of said formed reaction layer on said etching target material is within said predetermined amount.

6. The etching method according to claim 5,

wherein said at least one mask comprises a first and a second mask,

wherein said thickness is one or more of a thickness between opposing sides of an opening in said first mask, a thickness between opposing sides of an opening in said second mask, a thickness of the formed reaction layer on said first mask, a thickness of the formed reaction layer on said second mask, and said thickness of said formed reaction layer on said etching target material, and

wherein said removal step comprises removing the reaction layer remaining after the desorption step until one or more of said thickness between opposing sides of said opening in said first mask, said thickness between opposing sides of said opening in said second mask, said thickness of the formed reaction layer on said first mask, said thickness of the formed reaction layer on said second mask, and said thickness of said formed reaction layer on said etching target material is within said predetermined amount.

7. An etching method comprising:

a reaction layer forming step of forming a reaction layer by adsorption of a gas on a surface of an etching target material;

a desorption step of desorbing the reaction layer after the reaction layer forming step; and

a removal step of removing a deposited film,

wherein the surface of the etching target material is etched by the reaction layer forming step and the desorption step, and

wherein the removal step is performed in a case where the thickness of the deposited film is monitored by an optical method and the monitored thickness of the deposited film is thicker than a predetermined amount.

8. An etching method comprising:

a reaction layer forming step of forming a reaction layer by adsorption of a gas on a surface of an etching target material;

a desorption step of desorbing the reaction layer after the reaction layer forming step;

monitoring a thickness of a deposited film; and

when the thickness of the deposited film is greater than a predetermined amount, performing a removal step of removing the deposited film until a thickness of the deposited film is within said predetermined amount,

wherein the surface of the etching target material is etched by the reaction layer forming step and the desorption step.