Protection of dielectric window in inductively coupled plasma generation

• US 20030079838A1
• Filed: 10/22/2001
• Published: 05/01/2003
• Est. Priority Date: 10/22/2001
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Brcka, Jozef
• Granted Patent: US 6,666,982 B2
• Time in Patent Office: Days
• US Class Current: 156/345.48
• CPC Class Codes: C23C 14/3471 Introduction of auxiliary energy into the plasma
• CPC Class Codes: C23C 14/564 Means for minimising impurities in the coating chamber such as dust, moisture, residual gases
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32477 characterised by the means for protecting vessels or internal parts, e.g. coatings

Abstract

To protect a dielectric window in an inductively coupled plasma reactor from depositions of coating or etched material from the plasma, a dielectric insert is placed inside of the chamber closely adjacent the window. Where a slotted shield inside of the window protects the window from deposition, but has slots through which some material can pass in a direction toward the window, the insert is placed between the window and the shield. The insert is formed of a material that is compatible with the process being carried out on a semiconductor wafer within the chamber. Where the window and shield are planar, an unprocessed wafer of the same type and material as the wafer being processed is used for the insert.

Claims

1. A method of protecting a dielectric window in the wall of a plasma processing chamber from deposits of material from within the processing chamber in which a semiconductor wafer is being processed, the method comprising:

providing a replaceable wafer of the same material as the semiconductor wafer being processed inside of the chamber and replaceably mounted in close proximity to the window so as to protect the window from deposits of material from within the chamber.

2. The method of claim 1 wherein:

a slotted shield is provided inside of the chamber adjacent the window; and

the providing of the replaceable wafer includes inserting the replaceable wafer between the window and the shield.

3. The method of claim 1 wherein:

a slotted shield is provided inside of the chamber adjacent the window; and

the providing of the replaceable wafer includes;

inserting the replaceable wafer between the window and the shield, and

after processing one or more semiconductor wafers in the chamber, removing and replacing the replaceable wafer with another.

4. A method of protecting a dielectric window, in the wall of a plasma processing chamber through which energy is inductively coupled from an antenna outside of the chamber into a plasma within the chamber, from deposits of material from the processing chamber through slots in a protective shield that is spaced from the window inside of the chamber, the method comprising:

providing a replaceable dielectric insert between the window and the shield.

5. The method of claim 4 wherein a semiconductor wafer is being processed in the chamber and wherein:

the providing of the replaceable dielectric insert includes providing an insert that is compatible with the processing of the semiconductor wafer being processed inside of the chamber.

6. The method of claim 4 wherein a semiconductor wafer is being processed in the chamber and wherein:

the providing of the replaceable dielectric insert includes providing an insert in the form of a wafer of the same material as the semiconductor wafer being processed inside of the chamber.

7. A semiconductor wafer processing apparatus comprising:

a vacuum chamber bounded by a chamber wall having a dielectric window therein;

an RF source located outside of the window and configured to inductively couple energy into the chamber through the window to sustain an inductively coupled plasma in the chamber;

a slotted shield located inside of the chamber, close to and spaced from the window, so as to substantially prevent material from inside the chamber from forming a continuous layer covering the window; and

a replaceable dielectric insert located between the window and the shield so as to block material moving through slots in the shield toward the window from being deposited onto the window.

8. The method of claim 7 wherein the replaceable insert is a semiconductor wafer blank.