Method of manufacturing a semiconductor device

Patent metadata

Field	Value
Publication number	US-2018166290-A1
Application number	US-201715814999-A
Country	US
Kind code	A1
Filing date	Nov 16, 2017
Priority date	Dec 14, 2016
Publication date	Jun 14, 2018
Grant date	—

Abstract

Provided is a method of manufacturing a semiconductor device with which a trench shape having vertical, flat, and smooth side wall surfaces can be formed even at room temperature. A semiconductor substrate is placed on a sample stage which is kept at room temperature in a reaction container. A trench is formed in the semiconductor substrate by plasma etching that uses etching gas including oxygen and sulfur hexafluoride, while controlling the gas ratio of oxygen to sulfur hexafluoride so that the gas ratio is from 70% to 100%.

First claim

What is claimed is:

1 . A method of manufacturing a semiconductor device in which a trench is formed on a semiconductor substrate, comprising:
forming a mask of inorganic substance on a front surface of a semiconductor substrate so that the mask has an opening in a portion in which a trench is formed; controlling a temperature of a sample stage in a reaction container of an etching machine so as to keep the sample stage temperature constant; putting the semiconductor substrate on the sample stage; introducing etching gas including oxygen and sulfur hexafluoride to an interior of the reaction container while maintaining a flow rate ratio of oxygen to sulfur hexafluoride between 70% and 100%; and performing plasma etching of the semiconductor substrate with the etching gas to form the trench.

2 . A method of manufacturing a semiconductor device in which a trench is formed in a semiconductor substrate, comprising:
forming a mask from inorganic substance on a front surface of a semiconductor substrate so that the mask has an opening in a portion in which the trench is formed; controlling a temperature of a sample stage in a reaction container of an etching machine so as to keep the sample stage temperature constant; putting the semiconductor substrate on the sample stage; introducing etching gas including oxygen and sulfur hexafluoride to an interior of the reaction container while setting a flow rate ratio of oxygen to sulfur hexafluoride to a first ratio; a first etching step of performing plasma etching on the semiconductor substrate with the etching gas at the first ratio; introducing, after the first etching step, the etching gas including oxygen and sulfur hexafluoride to the interior of the reaction container while setting the flow rate ratio of oxygen to sulfur hexafluoride to a second ratio which is lower than the first ratio; and a second etching step of performing plasma etching on the semiconductor substrate with the etching gas at the second ratio.

3 . A method of manufacturing a semiconductor device according to claim 2 , wherein the first ratio and the second ratio which are flow rate ratios of oxygen to sulfur hexafluoride as the etching gas are between 70% and 100%.

4 . A method of manufacturing a semiconductor device in which a trench is formed in a semiconductor substrate, comprising:
forming a mask from inorganic substance on a front surface of a semiconductor substrate so that the mask has an opening in a portion in which the trench is formed; controlling a temperature of a sample stage in a reaction container of an etching machine so as to keep the sample stage temperature constant; putting the semiconductor substrate on the sample stage; performing plasma etching by introducing etching gas including oxygen and sulfur hexafluoride to an interior of the reaction container while setting a flow rate ratio of oxygen to sulfur hexafluoride to a first ratio; and continuing plasma etching by introducing the etching gas to the interior of the reaction container while changing the flow rate ratio of oxygen to sulfur hexafluoride to a second ratio which is lower than the first ratio in a single step instead of in stages.

5 . A method of manufacturing a semiconductor device according to claim 4 , wherein the first ratio and the second ratio which are flow rate ratios of oxygen to sulfur hexafluoride as the etching gas are between 70% and 100%.

6 . A method of manufacturing a semiconductor device according to claim 1 , wherein a sum of flow rates of the etching gas is constant.

7 . A method of manufacturing a semiconductor device according to claim 1 , wherein the temperature is from 5° C. to 30° C.

8 . A method of manufacturing a semiconductor device according to claim 1 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

9 . A method of manufacturing a semiconductor device according to claim 2 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

10 . A method of manufacturing a semiconductor device according to claim 3 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

11 . A method of manufacturing a semiconductor device according to claim 4 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

12 . A method of manufacturing a semiconductor device according to claim 5 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

13 . A method of manufacturing a semiconductor device according to claim 6 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

14 . A method of manufacturing a semiconductor device according to claim 7 , wherein the etching gas including oxygen and sulfur hexafluoride comprises only oxygen and sulfur hexafluoride.

Assignees

• Sii Semiconductor Corp

Inventors

• Kikuchi Akihiro
• Kuroda Takeshi
• Koseki Shintaro

Classifications

• H10P72/0421

  for drying etching · CPC title

• H10P50/695

  characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• H01J37/32192

  Microwave generated discharge (H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence) · CPC title

• C09K13/08

  containing a fluorine compound · CPC title