Method of monitoring deposit in chamber, method of plasma processing, method of dry-cleaning chamber, and semiconductor manufacturing apparatus

• US 5,897,378 A
• Filed: 10/19/1998
• Issued: 04/27/1999
• Est. Priority Date: 05/17/1995
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Eriguchi, Koji
• Primary Examiner(s): POWELL, WILLIAM A
• Application Number:
  US09/174,555
• Time in Patent Office: 190 Days
• Field of Search: 156/345 LC, 156/345 MT, 156/345 LT, 156/345 B, 216/59, 216/60, 216/66, 216/67, 216/84, 216/85, 134/1, 134/1.1, 134/31, 438/8, 438/9, 438/14, 438/16, 438/707, 438/710, 118/712, 118/620, 118/715, 118/723
• US Class Current: 438/707
• CPC Class Codes: C23C 16/4405 Cleaning of reactor or parts inside the reactor by using reactive gases
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32972 Spectral analysis
• CPC Class Codes: H01L 21/67063 for etching

Abstract

In the process of dry etching or the like, the bond between specific atoms contained in a deposit attached on the interior wall of a chamber and composed of an etching by-product is monitored by using an infrared ray. An incoming infrared ray generated from a light source for monitoring is directed to the deposit so that the absorption spectrum of an outgoing infrared ray passing through the deposit is measured by an infrared-ray measuring device. As a result, accurate information on the inside of the chamber can be obtained and a reduction in production yield due to variations in etching characteristics and generated particles can be prevented. Moreover, the availability of an apparatus can be increased by optimizing a maintenance cycle based on a specific variation in the absorption spectrum of the infrared ray. In particular, process administration and process control in such processing using plasma as dry etching and plasma CVD can be improved.

Claims

1. A method of monitoring a deposit in a chamber, comprising the steps of:

forming a part of the chamber with a window for electromagnetic wave permitting at least any one of electromagnetic waves including a light beam, an X-ray beam, and an electron beam to pass therethrough;

introducing said electromagnetic wave into said chamber from an outside of said chamber through said window for electromagnetic wave;

ejecting the electromagnetic wave passing through the deposit in said chamber from said chamber to the outside thereof; and

measuring absorption of said ejected electromagnetic wave by said deposit to monitor a state of said deposit.

2. A method of monitoring a deposit in a chamber according to claim 1, wherein

first and second windows for electromagnetic wave are formed at two opposing positions of said chamber and

the electromagnetic wave introduced into said chamber through said first window for electromagnetic wave is ejected from the chamber to the outside thereof through said second window for electromagnetic wave.

3. A method of monitoring a deposit in a chamber according to claim 2, wherein

said electromagnetic wave is introduced into the chamber through said first window for electromagnetic wave, directed to the deposit on an interior wall of said chamber located between said first and second windows for electromagnetic wave, reflected after passing through the deposit, and ejected from the chamber to the outside thereof through said second window for electromagnetic wave.

4. In a method of monitoring a deposit in a chamber according to claim 1, wherein

a part of said chamber is provided with a cylindrical monitoring member outwardly protruding and closed at a tip thereof, said cylindrical monitoring member being formed with first and second windows for electromagnetic wave at two opposing positions of a side thereof and

the electromagnetic wave is introduced into the chamber through said first window for electromagnetic wave, reflected after passing through the deposit on an inner surface of the tip of said cylindrical monitoring member, and ejected from said chamber to the outside thereof through said second window for electromagnetic wave.

5. A method of monitoring a deposit in a chamber according to claim 1, wherein

the state of said deposit is monitored by using the effect of an electromagnetic wave seeping into said deposit on an inner surface of said window for electromagnetic wave and partly absorbed by said deposit when the electromagnetic wave entering said window for electromagnetic wave from an outer surface thereof is totally reflected by the inner surface of said window for electromagnetic wave.

6. A method of monitoring a deposit in a chamber according to claim 1, wherein

said deposit is a polymer of at least either one of carbon and silicon and a halogen element,

said electromagnetic wave is an infrared ray, and

the state of said deposit is monitored by measuring an absorption spectrum of the infrared ray passing through said deposit.

7. A method of monitoring a deposit in a chamber according to claim 6, wherein

of said absorption spectrum of the infrared ray, a portion with a wave number of 2000 cm^-1 or less is measured.

8. A method of monitoring a deposit in a chamber according to claim 7, wherein

said deposit is produced when a material to be processed composed of silicon is processed with a plasma and

of said absorption spectrum of the infrared ray, a portion with a wave number in a range of 1450 to 1400 cm^-1 is measured.

9. A method of monitoring a deposit in a chamber according to claim 7, wherein

said deposit is produced when a material to be processed composed of silicon dioxide is processed and

of said absorption spectrum of the infrared ray, a portion with a wave number in a range of 1300 to 800 cm^-1 is measured.

10. A method of monitoring a deposit in a chamber according to claim 1, wherein

said chamber is constructed such that at least one of dry etching, plasma CVD, plasm ashing, plasma oxidation, impurity doping, and plasma-assisted epitaxy is performed therein.

11. A method of monitoring a deposit in a chamber according to claim 1, wherein

the state of said deposit is monitored by measuring a total amount of electromagnetic wave passing through said deposit.

12. A method of monitoring a deposit in a chamber according to claim 1, wherein

said chamber is constructed such that plasma processing is performed therein and,

after a variation in a emission intensity of a plasma in the chamber is measured and a sensitivity with which the emission intensity is measured is compensated such that the emission intensity at an initiation of the plasma processing has a constant initial value, when process control is performed with respect to the plasma processing based on a variation in the compensated emission intensity, the state of said deposit is monitored to compensate the sensitivity with which the emission intensity is measured.

13. A method of monitoring a deposit in a chamber according to claim 12, wherein

the process control performed with respect to said plasma processing is of determining a time at which dry etching should be completed.

14. A method of monitoring a deposit in a chamber according to claim 1, wherein

the state of said deposit is monitored to determine a time at which maintenance should be performed with respect to the chamber.

15. A method of plasma processing implemented by using a plasma processing apparatus, said apparatus having a chamber and a window for plasma provided in a part of said chamber to measure light emitted from a plasma in the chamber, said method comprising:

a first step of mounting a material to be processed in said chamber;

a second step of introducing processing gas having such a characteristic as to produce a deposit during plasma processing;

a third step of ionizing the introduced processing gas with an RF electric field to generate the plasma and processing said material to be processed by utilizing said plasma; and

a fourth step of measuring a emission intensity of the plasma in the chamber through said window for plasma, compensating a sensitivity with which the emission intensity in performing the plasma processing is measured such that the emission intensity has a constant initial value, and performing process control with respect to the plasma processing based on a variation in the compensated emission intensity, while said processing is performed.

16. A method of plasma processing according to claim 15, wherein

a part of said chamber is formed with a window for electromagnetic wave permitting at least any one of electromagnetic waves including a light beam, an X-ray beam, and an electron beam to pass therethrough and

in said fourth step, said electromagnetic wave is introduced into said chamber from an outside thereof through said window for electromagnetic wave and ejected from the chamber to the outside thereof after passing through said deposit such that the amount of absorption of the ejected electromagnetic wave by said deposit is measured and that the sensitivity with which said emission intensity is measured is compensated based on the amount of absorption.

17. A method of plasma processing according to claim 16, wherein

in said fourth step, the state of the deposit is monitored by using an electromagnetic wave seeping into said deposit on an inner surface of said window for electromagnetic wave and partly absorbed by said deposit when the electromagnetic wave entering said window for electromagnetic wave from an outer surface thereof is totally reflected by the inner surface of said window for electromagnetic wave.

18. A method of plasma processing according to claim 15, wherein

the plasma processing in said third step is dry etching and the process control performed with respect to the plasma processing in said fourth step is of determining a time at which dry etching should be completed.

19. A method of plasma processing according to claim 18, wherein

at a time when a gain in compensating the sensitivity with which the emission intensity is measured surpasses a given value in said third step, it is judged that maintenance should be performed in the chamber.

20. A method of plasma processing according to claim 16, wherein

at an earlier time when a gain in compensating the sensitivity with which the emission intensity is measured surpasses a given value in said third step or when the amount of absorption of said electromagnetic wave by said deposit surpasses a given value, it is judged that maintenance should be performed in the chamber.

21. A method of plasma processing according to claim 16, wherein

the plasma processing performed in said third step is dry etching and

a combination between said material to be processed and processing gas produces a polymer of at least either one of carbon and silicon and a halogen element.

22. A method of dry-cleaning a chamber having a window for electromagnetic wave permitting at least any one of electromagnetic waves including a light beam, an X-ray beam, and an electron beam to pass therethrough, said method comprising:

a first step of introducing cleaning gas into said chamber;

a second step of removing a deposit on an interior wall of said chamber with said cleaning gas; and

a third step of monitoring, while performing said second step, a state of said deposit by. introducing said electromagnetic wave into said chamber from an outside thereof through said window for electromagnetic wave, ejecting the electromagnetic wave passing through said deposit from said chamber to the outside thereof, and measuring an amount of absorption of the ejected electromagnetic wave by said deposit, wherein

when the amount of absorption of the electromagnetic wave by said deposit measured in said third step becomes a given value or lower, said second step is completed.

23. A method of dry-cleaning a chamber according to claim 22, wherein

the state of said deposit is monitored by using an electromagnetic wave seeping into said deposit on an inner surface of said window for electromagnetic wave and partly absorbed by said deposit when the electromagnetic wave entering said window for electromagnetic wave from an outer surface thereof is totally reflected by the inner surface of said window for electromagnetic wave.