Etching isolation features and dense features within a substrate

Patent metadata

Field	Value
Publication number	US-12119232-B2
Application number	US-202217847971-A
Country	US
Kind code	B2
Filing date	Jun 23, 2022
Priority date	Dec 5, 2018
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

Systems and methods for etching different features in a substantially equal manner are described. One of the methods includes applying a low frequency bias signal during a low TCP state and applying a high frequency bias signal during a high TCP state. The application of the low frequency bias signal during the low TCP state facilitates generation of hot neutrals, which are used to increase an etch rate of etching dense features compared to an etch rate for etching isolation features. The application of the high frequency bias signal during the high TCP state facilitates generation of ions to increase an etch rate of etching the isolation features compared to an etch rate of etching the dense features. After applying the low frequency bias signal during the low TCP state and the high frequency bias signal during the high TCP state, the isolation and dense features are etched similarly.

First claim

What is claimed is:

1. A method for etching isolation and dense features within a substrate, comprising:
supplying a first frequency bias radio frequency (RF) signal to a first impedance matching circuit;
supplying a second frequency bias RF signal to the first impedance matching circuit; and
pulsing a third RF signal between a first state and a second state to provide the third RF signal to a second impedance matching circuit, wherein the first frequency bias RF signal is supplied during the first state to etch the dense features and the second frequency bias RF signal is supplied during the second state to etch the isolation features.

2. The method of claim 1 , wherein the first frequency bias RF signal is a low frequency bias RF signal, the second frequency bias RF signal is a high frequency bias RF signal and the third RF signal is a transformer coupled plasma (TCP) RF signal.

3. The method of claim 2 , wherein the first state is a low TCP state and the second state is a high TCP state.

4. The method of claim 1 , wherein the first frequency bias RF signal has a plurality of states and the second frequency bias RF signal has a plurality of states.

5. The method of claim 4 , wherein the plurality of states of the first frequency bias RF signal is four, and the plurality of states of the second frequency bias RF signal is three.

6. The method of claim 4 , wherein the plurality of states of the first frequency bias RF signal is three, and the plurality of states of the second frequency bias RF signal is two.

7. The method of claim 4 , wherein the plurality of states of the first frequency bias RF signal is two, and the plurality of states of the second frequency bias RF signal is two.

8. The method of claim 1 , wherein the first state of the third RF signal has a lower parameter level than the second state of the third RF signal.

9. The method of claim 1 , wherein the first frequency bias RF signal is not supplied during the second state and the second frequency bias RF signal is not supplied during the first state.

10. The method of claim 1 , wherein the first and second states occur during a clock cycle of a clock signal.

11. The method of claim 1 , further comprising:
outputting a first modified bias RF signal from the first impedance matching circuit to a plasma chamber upon receiving the first frequency bias RF signal and the second frequency bias RF signal; and
outputting a second modified RF signal from the second impedance matching circuit to the plasma chamber upon receiving the third RF signal.

12. The method of claim 1 , wherein the first frequency bias RF signal is pulsed during the first state to decrease an angular spread of high energy neutrals for increasing an etch rate of etching the dense features, and wherein the second frequency bias RF signal is pulsed during the second state to decrease an angular spread of ions for increasing an etch rate of etching the isolation features.

13. The method of claim 1 , wherein the first state is a first source state and the second state is a second source state, wherein the first frequency bias RF signal is pulsed during the first source state from a first frequency first bias state to a first frequency second bias state and from the first frequency second bias state to a first frequency third bias state to decrease an angular spread of high energy neutrals for increasing an etch rate of etching the dense features, and wherein the second frequency bias RF signal is pulsed during the second source state from a second frequency first bias state to a second frequency second bias state to decrease an angular spread of ions for increasing an etch rate of etching the isolation features.

14. The method of claim 1 , wherein the first frequency bias RF signal transitions from a first frequency first bias state to a first frequency second bias state, and wherein the second frequency bias RF signal transitions from a second frequency first bias state to a second frequency second bias state.

15. The method of claim 1 , wherein the first frequency bias RF signal is pulsed during the first state from a first frequency first bias state to a first frequency second bias state to decrease an angular spread of high energy neutrals for increasing an etch rate of etching the dense features, and wherein the second frequency bias RF signal has an on state during the second state.

16. The method of claim 1 , wherein the first frequency bias RF signal has an on state during the first state, and wherein the second frequency bias RF signal has an on state during the second state.

17. A system for etching isolation and dense features within a substrate, comprising:
a first frequency radio frequency (RF) generator configured to supply a first frequency bias RF signal to a first impedance matching circuit;
a second frequency RF generator configured to supply a second frequency bias RF signal to the first impedance matching circuit; and
a third RF generator configured to pulse a third RF signal between a first state and a second state to provide the third RF signal to a second impedance matching circuit, wherein the first frequency bias RF signal is supplied during the first state to etch the dense features and the second frequency bias RF signal is supplied during the second state to etch the isolation features.

18. The system of claim 17 , wherein the first frequency bias RF signal has a plurality of states and the second frequency bias RF signal has a plurality of states.

19. A controller for etching isolation and dense features within a substrate, comprising:
one or more processors configured to:
control a first frequency radio frequency (RF) generator to supply a first frequency bias RF signal to a first impedance matching circuit;
control a second frequency RF generator to supply a second frequency bias RF signal to the first impedance matching circuit; and
control a third RF generator to pulse a third RF signal between a first state and a second state and to provide the third RF signal to a second impedance matching circuit;

wherein the one or more processors are further configured to:
control the first frequency RF generator to supply the first frequency bias RF signal during the first state to etch the dense features; and
control the second frequency RF generator to supply the second frequency bias RF signal during the second state to etch the isolation features; and

a memory device coupled to the one or more processors.

20. The controller of claim 19 , wherein the first frequency bias RF signal has a plurality of states and the second frequency bias RF signal has a plurality of states.

Assignees

• Lam Res Corp

Inventors

• Shoeb Juline
• Paterson Alexander Miller
• Wu Ying

Classifications

• H10P50/242 Primary

  of Group IV materials · CPC title

• H01J37/321

  the radio frequency energy being inductively coupled to the plasma · CPC title

• H01J37/3053

  for evaporating or etching · CPC title

• H01J37/32183 Primary

  Matching circuits · CPC title

• H01L21/3065 Primary

  Electricity · mapped topic