Etch method using a dielectric etch chamber with expanded process window

• US 6,403,491 B1
• Filed: 11/01/2000
• Issued: 06/11/2002
• Est. Priority Date: 11/01/2000
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Wang, Judy, Komatsu, Takehiko, Doan, Kenny L, Chang, Melody, Kim, Yunsang, Liu, Jingbao, Wang, Ruiping, Bjorkman, Claes, Shan, Hongching, Pu, Bryan Y
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): Tran, Binh X.
• Application Number:
  US09/704,867
• Time in Patent Office: 587 Days
• Field of Search: 438/710, 438/711, 438/712, 438/714, 438/715, 438/723, 438/724, 438/728, 438/733
• US Class Current: 438/710
• CPC Class Codes: H01J 37/32522 Temperature
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks
• CPC Class Codes: H01L 21/6875 characterised by a plurality of individual support members, e.g. support posts or protrusions
• CPC Class Codes: H01L 21/68757 characterised by a coating or a hardness or a material
• CPC Class Codes: H01L 21/68785 characterised by the mechanical construction of the susceptor, stage or support
• CPC Class Codes: H01L 21/68792 characterised by the construction of the shaft
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 21/76897 Formation of self-aligned vias or contact plugs, i.e. involving a lithographically uncritical step self-aligned silicidation on field effect transistors H01L29/665
• CPC Class Codes: H01L 2924/3011 Impedance

Abstract

A method for etching a dielectric in a thermally controlled plasma etch chamber with an expanded processing window. The method is adapted to incorporate benefits of a the thermal control and high evacuation capability of the chamber. Etchent gases include hydrocarbons, oxygen and inert gas. Explanation is provided for enablling the use of hexafluoro-1,3-butadiene in a capacitively coupled etch plasma. The method is very useful for creating via, self aligned contacts, dual damascene, and other dielectric etch.

Claims

1. A method of plasma etching features on a dielectric layer on a substrate disposed in a magnetically enhanced thermally controlled plasma etch chamber, comprising:

(a) disposing a substrate in a processing region of a thermally controlled plasma etch chamber;

(b) controlling the temperature of a wall disposed adjacent to the processing region of the thermally controlled plasma etch chamber to create a low temperature that is conducive to adhesion of polymer by-product on said wall;

(c) controlling the temperature of a substrate support;

(d) maintaining a pressure in the processing region;

(e) flowing a gas composition through a nozzle and into the processing region, said nozzle being at a temperature that is higher than said wall to prevent to adhesion of polymer by-product on said nozzle;

(f) coupling RF energy into the processing region to form a plasma from the gas composition; and

(g) providing a magnetic field in the processing region and transverse to the substrate.

2. A method of plasma etching features on a dielectric layer according to claim 1 wherein step (d) comprises evacuating the processing region at between about 1400 to about 1800 liters per minute.

3. A method of plasma etching features on a dielectric layer according to claim 1 wherein the step (c) is performed by circulating a fluid in a channel formed within a liner disposed adjacent to the processing region.

4. A method of plasma etching features on a dielectric layer according to claim 1 wherein step (f) comprises capacitively coupling RF energy.

5. A method of plasma etching features on a dielectric layer according to claim 1 wherein step (g) comprises rotating the magnetic field.

6. A method of plasma etching features on a dielectric layer according to claims 1, further comprising forming a magnetic field transverse to a pumping annulus of the magnetically enhanced thermally controlled plasma etch chamber.

7. A method of plasma etching features on a dielectric layer according to claim 1 wherein the gas composition comprises a fluorocarbon, an oxygen comprising gas and an inert gas wherein the total flow of the gas composition is between about 400 sccm to about 800 sccm.

8. A method of plasma etching features on a dielectric layer according to claim 1, further comprising evacuating the chamber at a rate providing a residence time of less than about 70 ms in said chamber.

9. A method of plasma etching features on a dielectric layer according to claim 1 wherein the gas composition comprises a fluorocarbon gas having a C:

F ratio of 1;

3, and a gas comprising carbon and oxygen wherein the total flow of the gas composition between about 200 sccm to about 400 sccm.

10. A method of plasma etching features on a dielectric layer according to claims 9 wherein the fluorocarbon gas is C₂F₆, the gas comprising carbon and oxygen is CO and the feature is a dual damascene trench.

11. A method of plasma etching features on a dielectric layer according to claim 1, wherein the gas composition comprises a hydrofluorocarbon gas, a fluorocarbon gas, and an oxygen comprising gas wherein the total flow of the gas composition is between about 50 sccm to about 200 sccm.

12. A method of plasma etching features on a dielectric layer according to claim 11, wherein the hydrofluorocarbon is CHF₃, the fluorocarbon gas is CF₄, and the oxygen comprising gas is O₂.

13. A method of plasma etching features on a dielectric layer according to claim 1 wherein the gas composition comprises a hydrofluorocarbon gas, a fluorocarbon gas, an oxygen comprising gas and an inert gas wherein the total flow of the gas composition between about 50 sccm to about 200 sccm.

14. A method of plasma etching features on a dielectric layer according to claim 13 wherein the fluorocarbon gas is CF₄, the hydrofluorocarbon gas is CHF₃, the oxygen comprising gas is O₂, the inert gas is argon, the pressure in the processing chamber is between about 20 mT to about 80 mT.

15. A method of plasma etching features on a dielectric layer according to claim 1, wherein the gas composition comprises a first fluorocarbon having a C:

F ratio of 1;

3, a second fluorocarbon having a C;

F ratio of 2;

1, and an inert gas, and wherein the total flow of the gas composition is between about 200 sccm to about 300 sccm.

16. A method of plasma etching features on a dielectric layer according to claim 15, wherein the first fluorocarbon gas comprises about 14 to about 18 percent of the total flow of the gas composition, the second fluorocarbon gas comprises between about 13 to about 16 percent of the total flow of the gas composition and the inert gas comprises more than 65 percent of the gas composition.

17. A method of plasma etching features on a dielectric layer according to claims 16, wherein the first fluorocarbon gas is C₂F₆, the second fluorocarbon gas is C₄F₈.

18. A method of plasma etching features on a dielectric layer according to claim 1 wherein the gas composition comprises a fluorocarbon, an oxygen comprising gas and an inert gas wherein the total flow of the gas composition between about 300 sccm to about 500 sccm.

19. A method of plasma etching features on a dielectric layer according to claim, 18 wherein the fluorocarbon gas is C₄F₆, and the oxygen comprising gas is O₂.

20. A method of plasma etching features on a dielectric layer according to claim 18, wherein the pressure in the processing chamber is between about 20 mT to about 60 mT, and further comprises maintaining a 35°

C. temperature difference between the wall temperature and the substrate support temperature.

21. A method of plasma etching features on a dielectric layer according to claim 18, wherein the fluorocarbon comprises about 3 to about 5 percent of the total flow of the gas composition, the oxygen comprising gas comprises between about 1 to about 4 percent of the total flow of the gas composition and the inert gas comprises more than 90 percent of the gas composition.

22. A method of plasma etching features on a dielectric layer according to claims 21, wherein the fluorocarbon gas is C₄F₆, and the oxygen comprising gas is O₂.

23. A method of plasma etching features on a dielectric layer according to claim 18, wherein the ratio of the fluorocarbon gas flow to the inert gas flow is about 0.5 and the ratio of the oxygen comprising gas flow to the inert gas flow is about 0.03.

24. A method of plasma etching features on a dielectric layer according to claim 23 wherein the fluorocarbon comprises about 7 to about 10 percent of the total flow of the gas composition, the oxygen comprising gas comprises between about 4 to about 6 percent of the total flow of the gas composition and the inert gas comprises more than 80 percent of the gas composition, and wherein said fluorocarbon comprises hexafluoro-1,3-butadiene.