Multi-station decoupled reactive ion etch chamber

• US 8,366,829 B2
• Filed: 07/02/2007
• Issued: 02/05/2013
• 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
• Primary Examiner(s): MOORE, KARLA A
• Application Number:
  US11/772,726
• Publication Number:
  US 20080011424A1
• Time in Patent Office: 2,045 Days
• Field of Search: 118/719, 156/345.31, 156/345.32, 204/298.23, 204/298.25, 204/298.26, 204/298.35
• US Class Current: 118/719
• 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 having a grounded wall 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 a corresponding one of the cathodes,

wherein the first frequency is higher than the second frequency; and

,

two movable dielectric isolation rings, each provided at one processing region and each being vertically movable between loading/unloading position and processing position, each isolation ring defining peripheral boundary of each processing region when the isolation ring assumes its processing position, wherein each isolation ring has a thickness, T, such that it prevents return path from the plasma via the grounded wall, whereby the RF return path is controlled to flow via the anode.

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 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.

6. The plasma processing chamber of claim 5, 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 frequency, and said low frequency matching circuit presents high impedance to the first frequency.

7. The plasma processing chamber of claim 6, wherein the first frequency is selected from about 27 MHz, about 60 MHz, or about 100 MHz.

8. The plasma processing chamber of claim 6, wherein the second frequency is selected from the range of about 500 KHz to 2.2 MHz.

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

10. The plasma processing chamber of claim 9, further comprising a plurality of switches, each operable for selecting one of the first, second and third RF frequencies.

11. A tandem plasma etch chamber, comprising:

a conductive chamber body having a grounded wall 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; and

,

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

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

,

wherein the first and second isolation rings assume a first position for wafer loading/unloading and assumes a second position for wafer processing, and wherein each of the first and second isolation rings has a thickness, T, such that it prevents return path from the plasma via the grounded wall, whereby the RF return path is controlled to flow via the first and second electrodes.

12. The tandem plasma etch chamber of claim 11, 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.

13. The tandem plasma etch chamber of claim 12, wherein each of the first and second plasma confinement rings comprises a plasma shield and an RF shield.

14. The tandem plasma etch chamber of claim 12, wherein the plasma shield comprises a conductive but floating member and the RF shield comprises a grounded conductive member.

15. The tandem plasma etch chamber of claim 11, 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.

16. The tandem plasma etch chamber of claim 11, 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.

17. The tandem plasma etch chamber of claim 11, wherein each of the first process region and a second process region can be operated independently of the other.