MULTI-STATION DECOUPLED REACTIVE ION ETCH CHAMBER

• US 20080011424A1
• Filed: 07/02/2007
• Published: 01/17/2008
• Est. Priority Date: 08/05/2005
• Status: Active Grant

• Current Assignee: Advanced Micro-Fabrication Equipment Inc.
• Original Assignee: Advanced Micro-Fabrication Equipment Inc.
• Inventors: YIN, Gerald, Ni, Tuqiang, Chen, Jinyuan, Qian, Xueyu
• Granted Patent: US 8,366,829 B2
• Time in Patent Office: Days
• US Class Current: 156/345.48
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32165 Plural frequencies
• CPC Class Codes: H01J 37/32183 Matching circuits
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/32633 Baffles
• CPC Class Codes: H01J 37/32642 Focus rings
• CPC Class Codes: H01J 37/32889 Connection or combination with other apparatus
• CPC Class Codes: H01J 37/32899 Multiple chambers, e.g. cluster tools
• CPC Class Codes: H01L 21/67161 characterized by the layout of the process chambers
• CPC Class Codes: H01L 21/67173 in-line arrangement
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers

Abstract

A tandem processing-zones chamber having plasma isolation and frequency isolation is provided. At least two RF frequencies are fed from the cathode for each processing zones, where one frequency is about ten times higher than the other, so as to provide decoupled reactive ion etch capability. The chamber body is ground all around and in-between the two processing zones. The use of frequency isolation enables feed of multiple RF frequencies from the cathode, without having crosstalk and beat. A plasma confinement ring is also used to prevent plasma crosstalk. A grounded common evacuation path is connected to a single vacuum pump.

Claims

1. A plasma processing chamber having at least two processing regions to enable individual or simultaneous processing of at least two wafers, comprising:

a chamber body defining at least two plasma processing regions, each processing region having a cathode situated at a lower part thereof and an anode situated in a ceiling thereof, said chamber body defining an evacuation path;

at least one vacuum pump coupled to the evacuation path;

at least two RF match circuits, each RF match circuit simultaneously coupling at least a first RF frequency and a second RF frequency to one of the cathodes; and

,

wherein the first frequency is higher than the second frequency.

2. The plasma processing chamber of claim 1, further comprising at least two plasma confinement rings, each situated about a corresponding cathode and preventing plasma communication from a processing region to the evacuation path.

3. The plasma processing chamber of claim 2, wherein each plasma confinement ring comprises a plasma shield and an RF shield.

4. The plasma processing chamber of claim 3, wherein the plasma shield comprises a conductive but floating member and the RF shield comprises a grounded conductive member.

5. The plasma processing chamber of claim 1, further comprising two movable dielectric isolation rings, each provided at one processing region, each isolation ring defining peripheral boundary of each processing region when the isolation ring assumes its lowered position.

6. The plasma processing chamber of claim 5, wherein the chamber body defines a grounded chamber wall for each processing region, and wherein each isolation ring has a thickness designed to shield the grounded chamber wall from RF energy.

7. The plasma processing chamber of claim 6, wherein each isolation ring further comprises at least one pressure equalizing passage.

8. The plasma processing chamber of claim 7, further comprising a partition wall separating each of two processing regions, wherein the partition wall comprises a pressure equalizing channel, said pressuring equalizing channel mating with the pressure equalizing passage when the isolation ring assumes its lower position.

9. The plasma processing chamber of claim 1, further comprising a plurality of RF conductors, each coupling energy from one RF match circuit to a corresponding cathode, each of the RF conductors having a plurality of prongs spaced in even radial distance so as to couple the RF energy onto a respective cathode in an even manner.

10. The plasma processing chamber of claim 9, wherein each of the RF match circuits comprises a high frequency input, a low frequency input, a combined output, a high frequency matching circuit coupled between the high frequency input and combined output, a low frequency matching circuit coupled between the low frequency input and the combined output, and wherein the high frequency matching circuit presents high impedance to the second and fourth frequencies, and said low frequency matching circuit presents high impedance to the first and third frequencies.

11. The plasma processing chamber of claim 10, wherein the first frequency is selected from about 27 MHz, about 60 MHz, or about 100 MHz.

12. The plasma processing chamber of claim 10, wherein the second frequency is selected from the range of about 500 KHz to 2.2 MHz.

13. The plasma processing chamber of claim 1, wherein each of the RF match circuits further couples a third RF frequency to a corresponding cathode.

14. The plasma processing chamber of claim 13, further comprising a plurality of switches, each operable for selecting one of the first, second and third RF frequencies.

15. A tandem plasma etch chamber, comprising:

a conductive chamber body defining a first process region and a second process region;

the chamber body having a partition wall separating the first process region and the second process region;

said chamber body further comprising an evacuation chamber in fluid communication with the first process region and the second process region;

said evacuation chamber having a single evacuation port;

the chamber body coupled to a ground potential;

a vacuum pump coupled to the evacuation port;

a first fixed cathode affixed at bottom part of the first process region and comprising a first chuck for supporting a wafer;

a first showerhead affixed at a ceiling of the first process region;

the first showerhead comprising a first electrode;

a second fixed cathode affixed at bottom part of the second process region and comprising a second chuck for supporting a wafer;

a second showerhead affixed at a ceiling of the second process region;

the second showerhead comprising a second electrode;

a common gas source providing process gas to the first showerhead and the second showerhead;

a first RF match concurrently coupling at least one low RF frequency and one high RF frequency to the first cathode;

a second RF match concurrently coupling at least one low RF frequency and one high RF frequency to the second cathode;

wherein the high RF frequency is at least two times higher than the low RF frequency.

16. The tandem plasma etch chamber of claim 15, further comprising a first plasma confinement ring situated about the first cathode and preventing plasma communication from the first processing region to the evacuation chamber;

and a second plasma confinement ring situated about the second cathode and preventing plasma communication from the second processing region to the evacuation chamber.

17. The tandem plasma etch chamber of claim 16, wherein each of the first and second plasma confinement rings comprises a plasma shield and an RF shield.

18. The tandem plasma etch chamber of claim 16, wherein the plasma shield comprises a conductive but floating member and the RF shield comprises a grounded conductive member.

19. The tandem plasma etch chamber of claim 15, further comprising:

a first movable dielectric isolation ring provided at the first processing region;

a second movable dielectric isolation ring provided at the second processing region; and

,

wherein the first and second isolation rings assume an upper position for wafer loading and assumes a lower position for wafer processing.

20. The tandem plasma etch chamber of claim 19, wherein each of the first and second isolation rings has a thickness designed to shield the grounded chamber wall from RF energy.

21. The tandem plasma etch chamber of claim 20, wherein each of the first and second isolation rings further comprises at least one pressure equalizing passage.

22. The tandem plasma etch chamber of claim 21, wherein the partition wall comprises a pressure equalizing channel, said pressuring equalizing channel mating with pressure equalizing passages of the first and second isolation rings, when the first and second isolation rings assume the lower position.

23. The tandem plasma etch chamber of claim 15, wherein the low frequency is selected from the range of about 500 KHz to 2.2 MHz and the high frequency is selected from about 27 MHz, 60 MHz, and 100 MHz.

24. The tandem plasma etch chamber of claim 15, further comprising a first switch coupled to the first RF match and a second switch coupled to the second RF match, each of the first and second switches operable to select either of:

said low RF frequency from a selection of two low RF frequencies, or

said high RF frequency from a selection of two high RF frequencies.

25. The tandem plasma etch chamber of claim 15, wherein each of the first process region and a second process region can be operated independently of the other.

26. A decoupled reactive ion etch chamber, comprising:

a conductive chamber body defining a plurality of process regions;

the chamber body having partition walls separating the plurality of process regions from each other;

said partition walls comprising a fluid conductance channel to equate pressure among the process regions;

said chamber body further comprising an evacuation chamber in fluid communication with the process regions;

the chamber body coupled to a ground potential;

at least one vacuum pump coupled to the evacuation chamber;

a plurality of cathodes, each cathode affixed at bottom part of a corresponding one of the process regions and comprising a chuck for supporting a wafer;

a plurality of showerheads, each affixed at a ceiling of a corresponding one of the process regions and comprising an electrode;

a common gas source providing process gas to the showerheads;

a plurality of RF matches, each concurrently coupling at least one low RF frequency and one high RF frequency to a corresponding one of the cathodes.

27. The decoupled reactive ion etch chamber of claim 26, further comprising a plurality of plasma confinement rings, each situated about a corresponding cathode and preventing plasma communication from a processing region to the evacuation chamber.

28. The decoupled reactive ion etch chamber of claim 27, wherein each plasma confinement ring comprises a plasma shield and an RF shield.

29. The decoupled reactive ion etch chamber of claim 28, wherein the plasma shield comprises a conductive but floating member and the RF shield comprises a grounded conductive member.

30. The decoupled reactive ion etch chamber of claim 26, further comprising a plurality of movable dielectric isolation rings, each provided at one processing region, each isolation ring defining peripheral boundary of each processing region when the isolation ring assumes its lowered position.

31. The decoupled reactive ion etch chamber of claim 30, wherein each isolation ring has a thickness designed to shield the grounded chamber wall from RF energy.

32. The decoupled reactive ion etch chamber of claim 31, wherein each isolation ring further comprises at least one pressure equalizing passage, said pressure equalizing passage mating with the fluid conductance channel when the isolation ring assumes its lower position.