SYSTEMS AND METHODS FOR VARIABLE MODE PLASMA ENHANCED PROCESSING OF SEMICONDUCTOR WAFERS

• US 20020005392A1
• Filed: 11/16/1998
• Published: 01/17/2002
• Est. Priority Date: 11/17/1997
• Status: Active Grant

• Current Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area)
• Original Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area)
• Inventors: SAVAS, STEPHEN E., GEORGE, RENE, GUERRA, ROBERT, HELLE, WOLFGANG, RANFT, CRAIG, LUO, LEROY
• Granted Patent: US 6,379,576 B2
• Time in Patent Office: Days
• US Class Current: 216/67
• CPC Class Codes: G03F 7/427 using plasma means only
• CPC Class Codes: H01J 2237/335 Cleaning
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/32357 Generation remote from the workpiece, e.g. down-stream
• CPC Class Codes: H01L 21/02046 Dry cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: Y10S 134/902 Semiconductor wafer
• CPC Class Codes: Y10S 438/906 Cleaning of wafer as interim step

Abstract

Variable mode plasma system and method for processing a semiconductor wafer. The modulation of the plasma potential relative to the semiconductor wafer is varied for different process steps. A capacitive shield may be selectively grounded to vary the level of capacitive coupling and modulation of the plasma. Process pressures, gases and power level may also be modified for different process steps. Plasma properties may easily be tailored to specific layers and materials being processed on the surface of the wafer. Variable mode processes may be adapted for (i) removal of photoresist after high-dose ion implant, (ii) post metal etch polymer removal, (iii) via clean, and (iv) other plasma enhanced processes.

Claims

1. A reactor system for assisting the removal of residue from a wafer, the reactor system comprising:

a reactor chamber within which a plasma is generated to produce plasma products for assisting the removal of residue from the wafer wherein the plasma products include charged particles and neutral species;

a gas inlet through which gas is provided to the reactor chamber;

means for generating the plasma, the means for generating the plasma being adjacent to the plasma;

a support for the wafer positioned inside the chamber such that the wafer on the support is exposed to at least one plasma product during processing wherein a soluble compound is formed on the wafer from the chemical interaction of the plasma with the residue on the wafer.

2. The system of claim 1, wherein the means for generating the plasma includes a microwave power source.

3. The system of claim 1, wherein the residue includes aluminum and wherein the soluble compound formed on the wafer includes aluminum.

4. The system of claim 1, comprising means for controlling the plasma potential relative to the support such that the wafer is processed in at least two modes, a first mode and a second mode.

5. The system of claim 4, wherein the gas includes no more than 2% oxygen.

6. The system of claim 4, wherein the plasma potential relative to the support in the first mode induces bombardment of the wafer by charged particles from the plasma at a desired level for processing during the first mode;

wherein the plasma potential relative to the support in the second mode is controlled to substantially reduce bombardment of the wafer by charged particles during the second mode; and

wherein the wafer is exposed to neutral species from the plasma at a desired level for processing during the second mode.

7. A plasma reactor for processing a semiconductor wafer comprising:

a reactor chamber within which a plasma is generated to produce plasma products for processing the semiconductor wafer wherein the plasma products include charged particles and neutral species;

a gas inlet through which gas is provided to the reactor chamber;

an electrode adjacent to the plasma;

a power source operatively coupled to the electrode to provide power to the plasma;

a support for the semiconductor wafer positioned such that the wafer is exposed to at least one plasma product during processing;

means for controlling the plasma potential relative to the support such that the semiconductor wafer is processed in at least two modes, a first mode and a second mode;

wherein the plasma potential relative to the support in the first mode induces bombardment of the semiconductor wafer by charged particles from the plasma at a desired level for processing during the first mode;

wherein the plasma potential relative to the support in the second mode is controlled to substantially reduce bombardment of the semiconductor wafer by charged particles during the second mode; and

wherein the semiconductor wafer is exposed to neutral species from the plasma at a desired level for processing during the second mode.

8. The reactor of claim 7, wherein the gas includes a hydrogen containing gas, an oxygen containing gas, and a halogen containing gas.

9. The reactor of claim 8, wherein the halogen containing gas includes fluorine.

10. The reactor of claim 8, wherein the hydrogen containing gas includes a mixture of molecular nitrogen with molecular hydrogen containing about 4% molecular hydrogen.

11. The reactor of claim 8, wherein the gas is provided to the reactor chamber at a flow rate of 100 SCCM to 10,000 SCCM for the oxygen containing gas, 5 SCCM to 1,000 SCCM for the halogen containing gas, and 10 SCCM to 5,000 SCCM of the hydrogen containing gas.

12. The reactor of claim 8, wherein the means for controlling the plasma potential includes a slotted conducting structure surrounding the plasma.

13. The reactor of claim 12, wherein the slotted conducting structure is electrically coupled to ground in the second mode.

14. A method for processing a semiconductor wafer comprising:

generating a plasma to produce charged particles and neutral species;

inducing bombardment of the semiconductor wafer by charged particles from the plasma at a first level for a first mode of processing;

limiting bombardment of the semiconductor wafer to a level substantially less than the first level for a second mode of processing; and

exposing the semiconductor wafer to neutral species from the plasma during the second mode at a desired level for processing;

wherein the semiconductor wafer is selectively processed using both the first and the second modes of processing.

15. The method of claim 14, wherein the plasma includes a halogen, oxygen, and hydrogen.

16. The method of claim 15, wherein the halogen includes fluorine.

17. The method of claim 14, wherein generating the plasma includes flowing gas at a flow rate of 100 SCCM to 10,000 SCCM for an oxygen containing gas, 5 SCCM to 1,000 SCCM for a halogen containing gas, and 10 SCCM to 5,000 SCCM for a hydrogen containing gas.

18. The method of claim 15, wherein inducing bombardment of the semiconductor wafer by charged particles from the plasma at a first level includes surrounding the plasma with a slotted conducting structure.

19. The method of claim 18, wherein limiting bombardment of the semiconductor wafer to a level substantially less than the first level includes electrically coupling the slotted conducting structure to ground.

20. The method of claim 14, wherein inducing bombardment of the semiconductor wafer by charged particles from the plasma at a first level is performed for a period of 1 to 5 minutes.

21. The method of claim 14, comprising maintaining the semiconductor wafer at a temperature below about 100 degrees Celsius.