# US 12,009,220 B2 · Method for processing workpiece, plasma processing apparatus and semiconductor device

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- Number: US 12,009,220 B2
- Document ID: US12009220B2
- Status: Granted
- Kind: B2
- Application number: 17/489,162
- Filed: 2021-09-29
- Published: 2023-01-05
- Granted: 2024-06-11
- Earliest claimed: 2021-06-30
- Assignees: Beijing E-Town Semiconductor Technology Co., Ltd.; Mattson Technology, Inc.
- Applicants: Beijing E-Town Semiconductor Technology Co., Ltd.; Mattson Technology, Inc.
- Inventors: Fei Yu; Mengyang Xin; Junliang Li
- Web page: https://patentgrep.com/patent/US12009220B2

## CPC

- H10P 50/283: {by chemical means}
- H01J 37/321: {the radio frequency energy being inductively coupled to the plasma}
- H01J 37/3244: {Gas supply means}
- H01J 2237/332: Coating
- H01J 2237/334: Etching
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## 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.

## Claims

### Claim 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 CxHyFz, 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 1)

The method of claim 1, wherein the etching gas comprises Octafluorocyclobutane (C4F8).

### Claim 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 CxHyFz, 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 (CH2F2), Fluoroforni (CHF3), and Carbon tetrafluoride (CF4);
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%.

### Claim 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 CxHyFz 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.

### Claim 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 CxHyFz, 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.