ETCHING METHOD AND PLASMA PROCESSING APPARATUS

• US 20180269118A1
• Filed: 08/30/2017
• Published: 09/20/2018
• 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
• Granted Patent: US 10,665,516 B2
• Time in Patent Office: Days
• 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; and

a removal step of removing the reaction layer remaining after the desorption step or a deposited film, different from the desorption step, 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 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.

3. The etching method according to claim 2, wherein a processing condition of the removal step is determined based on the monitored thickness of the deposited film.

4. 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.

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

6. A plasma processing apparatus comprising:

a processing chamber for plasma-processing a sample containing an etching target material;

a radio frequency power source for supplying radio frequency power for generating plasma; and

a sample stage on which the sample is placed,

further comprising a control unit for determining a wavelength signal increased in a reaction layer forming step and decreased in a desorption step in an interference spectrum obtained by monitoring a surface of the etching target material etched by the reaction layer forming step and the desorption step during the reaction layer forming step, and performing control to perform a removal step based on a difference between the obtained signal and the monitored signal, wherein

the reaction layer forming step is a step of forming a reaction layer by adsorption of a gas on the surface of the etching target material, the desorption step is a step of desorbing the reaction layer after the reaction layer forming step, and the removal step is a step of removing the reaction layer remaining after the desorption step or a deposited film, different from the desorption step.