Use of an asymmetric waveform to control ion bombardment during substrate processing

• US 6,162,709 A
• Filed: 01/11/2000
• Issued: 12/19/2000
• Est. Priority Date: 12/01/1997
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Raoux, Sebastien, Mudholkar, Mandar
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): Kielin, Erik J.
• Application Number:
  US09/481,985
• Time in Patent Office: 343 Days
• Field of Search: 118/723 E, 118/723 R, 118/723 ER, 438/778, 438/791, 438/792, 438/798, 438/513
• US Class Current: 438/513
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/4557 Heated nozzles
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: C23C 16/515 using pulsed discharges
• CPC Class Codes: C23C 16/517 using a combination of discharges covered by two or more of groups C23C16/503 - C23C16/515
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32165 Plural frequencies
• CPC Class Codes: H01J 37/32706 Polarising the substrate

Abstract

A substrate processing system that includes a deposition chamber having a reaction zone, first and second electrodes, a mixed frequency RF power supply including a low frequency RF power source and a high frequency RF power source. The high frequency RF power supply provides enough power to form a plasma from a process gas introduced into the reaction zone and the low frequency RF power supply is configured to supply an asymmetrical waveform to either said first or second electrodes to bias the plasma toward the substrate.

Claims

1. A method for depositing a film on a substrate in a substrate processing chamber, said method comprising the steps of:

introducing one or more process gases via a gas inlet manifold into a reaction zone of the substrate processing chamber;

forming a plasma from said one or more process gases by applying high frequency RF power to said gas inlet manifold; and

biasing said plasma toward the substrate with an asymmetric low frequency RF waveform.

2. The method of claim 1 wherein said asymmetric low frequency RF waveform is a sawtooth waveform.

3. The method of claim 1 wherein said asymmetric low frequency RF waveform has a duty cycle of between 10 and 50 percent.

4. The method of claim 1 wherein said process gases comprise silane, ammonia and nitrogen.

5. The method of claim 4 wherein said asymmetric low frequency RF waveform has a frequency of less than 400 kHz.

6. The method of claim 4 wherein said asymmetric low frequency RF waveform has a frequency between 50 and 220 kHz.

7. The method of claim 1 wherein the plasma is biased toward the substrate to promote ion bombardment of the substrate.