Method for processing workpiece, plasma processing apparatus and semiconductor device

Patent metadata

Field	Value
Publication number	US-12009220-B2
Application number	US-202117489162-A
Country	US
Kind code	B2
Filing date	Sep 29, 2021
Priority date	Jun 30, 2021
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A method for processing a workpiece, a plasma processing apparatus and a semiconductor device are provided. The method includes placing a workpiece including a spacer layer on a workpiece support in a chamber; selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, the composition modulation gas includes one or more molecules, the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer; generating one or more species using one or more plasmas from a process gas to create a mixture, the process gas includes an etching gas and the composition modulation gas; and exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer.

First claim

What is claimed is:

1. A method for processing a workpiece, comprising:
placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises one or more molecules having a chemical formula C x H y F z , where x and z are natural numbers greater than zero, and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer;
generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises an etching gas and the composition modulation gas; and
exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece, wherein:
a first portion of the polymer layer is formed on a first region of the spacer layer, and a second portion of the polymer layer is formed on a second region of the spacer layer; and
the first region is higher than the second region, and a first thickness of the first portion is different from a second thickness of the second portion.

2. The method of claim 1 , wherein selecting the composition modulation gas comprises:
selecting the composition modulation gas to produce a first volume ratio of carbon and fluorine that is greater than or equal to a preset ratio, such that the first thickness is greater than the second thickness; or
selecting the composition modulation gas to produce a second volume ratio of carbon and fluorine that is less than the preset ratio, such that the first thickness is less than the second thickness.

3. The method of claim 1 , wherein the spacer layer is an oxide spacer layer.

4. The method of claim 1 , wherein the etching gas comprises Octafluorocyclobutane (C 4 F 8 ).

5. A method for processing a workpiece, comprising:
placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises:
one or more molecules having a chemical formula C x H y F z , where x and z are natural numbers greater than zero, and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer; and
one or more of Difluoromethane (CH 2 F 2 ), Fluoroforni (CHF 3 ), and Carbon tetrafluoride (CF 4 );

generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises:
an etching gas and the composition modulation gas; and
an inert gas; or, the process gas further comprises an inert gas and oxygen;

exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece, wherein a volume proportion of each component in the process gas is as follows:
the etching gas: about 10%-about 30%;
the composition modulation gas: about 5%-about 25%;
the oxygen: about 3%-about 10%; and
the inert gas: about 50%-about 80%.

6. A method for processing a workpiece, comprising:
placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises one or more molecules having a chemical formula C x H y F z where x and z are natural numbers greater than zero, and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer;
generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises an etching has and the composition modulation gas; and
exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece, wherein a processing parameter of the chamber comprises one or more of:
a pressure: about 5 mTorr-about 70 mTorr;
a source power: about 100 watts-about 500 watts;
a center power: about 50 watts-about 200 watts; and
a bias power: about 100 watts-about 500 watts.

7. A method for processing a workpiece, comprising:
placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises one or more molecules having a chemical formula C x H y F z , where x and z are natural numbers greater than zero and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer;
generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises an etching gas and the composition modulation gas; and
exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece wherein generating the one or more species further comprises:
providing a first radio frequency (RF) power to an induction coil to generate a first plasma from the process gas to generate a first mixture in the chamber, the first mixture comprising one or more first species; and
providing a second RF power to a bias electrode to generate a second plasma in the first mixture in the chamber to generate a second mixture, the second mixture comprising one or more second species,
wherein exposing the workpiece to the mixture comprises exposing the workpiece to the second mixture.

Assignees

• Beijing E Town Semiconductor Tech Co Ltd
• Mattson Tech Inc

Inventors

• Yu Fei
• Xin Mengyang
• Li Junliang

Classifications

• H10P50/283 Primary

  by chemical means · CPC title

• H10P72/0421

  for drying etching · CPC title

• H01J2237/334

  Etching · CPC title

• H01J2237/332

  Coating · CPC title

• H01J37/3244 Primary

  Gas supply means · CPC title