Apparatus and method for edge bevel removal of copper from silicon wafers

Patent metadata

Field	Value
Publication number	US-9685353-B2
Application number	US-201313857883-A
Country	US
Kind code	B2
Filing date	Apr 5, 2013
Priority date	Aug 27, 2008
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Chemical etching methods and associated modules for performing the removal of metal from the edge bevel region of a semiconductor wafer are described. The methods and systems provide the thin layer of pre-rinsing liquid before applying etchant at the edge bevel region of the wafer. The etchant is less diluted and diffuses faster through a thinned layer of rinsing liquid. An edge bevel removal embodiment involving that is particularly effective at reducing process time, narrowing the metal taper and allowing for subsequent chemical mechanical polishing, is disclosed.

First claim

What is claimed is:

1. An apparatus for removing unwanted metal deposited on an edge bevel area of a semiconductor wafer, the apparatus comprising:
a process chamber;
a wafer chuck for supporting and rotating the wafer during removal of the unwanted metal from the edge bevel area;
a nozzle for delivering a prerinse liquid to the wafer;
a nozzle for delivering a liquid etchant to the wafer; and
a controller comprising:
program instructions for rotating the wafer;
program instructions for prerinsing the wafer using the prerinse liquid;
program instructions for thinning a layer of the prerinse liquid through increasing the rotational speed of the wafer without drying the wafer; and
program instructions for delivering a stream of liquid etchant into the thinned layer of prerinse liquid near the edge bevel area of the rotating wafer.

2. The apparatus of claim 1 , further comprising a deflector shield positioned around the wafer chuck and configured to deflect the prerinse liquid away from the surface of the wafer.

3. The apparatus of claim 2 , wherein the prerinse liquid is deflected downward toward the bottom of the process chamber.

4. The apparatus of claim 3 , wherein the deflector shield is attached to the bottom of the process chamber.

5. The apparatus of claim 3 , wherein the deflector shield is attached to the wafer chuck and rotates together with the wafer chuck.

6. The apparatus of claim 1 , wherein the program instructions for increasing the rotational speed of the wafer include instructions for rotating the wafer at a rotational speed of at least about 600 rpm.

7. The apparatus of claim 6 , wherein the program instructions for increasing the rotational speed of the wafer comprise instructions for rotating the wafer at a rotational speed of at least about 900 rpm.

8. The apparatus of claim 1 , wherein the program instructions for prerinsing the wafer specify prerinsing for less than about 10 seconds.

9. The apparatus of claim 8 , wherein the program instructions for prerinsing the wafer specify prerinsing for less than about 5 seconds.

10. The apparatus of claim 1 , wherein the program instructions for delivering a stream of liquid etchant specify delivering the stream for less than about 30 seconds.

11. The apparatus of claim 10 , wherein the program instructions for delivering a stream of liquid etchant specify delivering the stream for less than about 25 seconds.

12. The apparatus of claim 1 , wherein the controller further comprises program instructions for rinsing at least some of the liquid etchant from the wafer.

13. The apparatus of claim 12 , wherein the program instructions for rinsing include instructions for rotating the wafer at a rotational speed of at least about 600 rpm.

14. The apparatus of claim 13 , wherein the program instructions for rinsing include instructions for rotating the wafer at a rotational speed of at least about 900 rpm.

15. The apparatus of claim 1 , wherein the program instructions for delivering a stream of liquid etchant include:
instructions for delivering a first stream of liquid etchant at a first flow rate and for a first duration; and
instructions for delivering a second stream of liquid etchant, after the first stream, at a second flow rate and for a second duration, the second flow rate being substantially less than the first flow rate, and the second duration being substantially longer than the first duration.

16. The apparatus of claim 15 , wherein:
the first flow rate is between about 0.25 and 0.35 ml/sec; and
the second flow rate is between about 0.10 and 0.20 ml/sec.

17. The apparatus of claim 16 , wherein:
the first duration is between about 1 and 5 seconds; and
the second duration is between about 10 and 30 seconds.

18. An apparatus for removing unwanted metal deposited on an edge bevel area of a semiconductor wafer, the apparatus comprising:
a process chamber;
a wafer chuck for supporting and rotating the wafer during removal of the unwanted metal from the edge bevel area;
a nozzle for delivering a prerinse liquid to the wafer;
a nozzle for delivering a thinning liquid to the wafer;
a nozzle for delivering a liquid etchant to the wafer and
a controller comprising:
program instructions for rotating the wafer;
program instructions for prerinsing the wafer using the prerinse liquid;
program instructions for thinning layer of the prerinse liquid by delivering a stream of the thinning liquid into the layer of the prerinse liquid near the edge bevel area of the rotating wafer without drying the wafer; and
program instructions for delivering a stream of liquid etchant into the thinned layer of prerinse liquid near the edge bevel area of the rotating wafer.

19. The apparatus of claim 18 , wherein the thinning liquid comprises a liquid selected from the group consisting of isopropyl alcohol, acetone, and a solution of water with a surfactant.

20. The apparatus of claim 18 , wherein program instructions for thinning a layer of the prerinse liquid comprise instructions for delivering a stream of heated thinning liquid into the layer of the prerinse liquid near the edge bevel area of the rotating wafer without drying the wafer.

21. An apparatus for removing unwanted metal deposited on an edge bevel area of a semiconductor wafer, the apparatus comprising:
a process chamber;
a wafer chuck for supporting and rotating the wafer during removal of the unwanted metal from the edge bevel area;
a nozzle for delivering a prerinse liquid to the wafer;
a nozzle for delivering a vapor or aerosol of a thinning liquid to the wafer;
a nozzle for delivering a liquid etchant to the wafer; and
a controller comprising:
program instructions for rotating the wafer;
program instructions for prerinsing the wafer using the prerinse liquid;
program instructions for thinning a layer of the prerinse liquid by delivering the vapor or aerosol of the thinning agent over the layer of the prerinse liquid near the edge bevel area of the rotating wafer without drying the wafer; and
program instructions for delivering a stream of liquid etchant into the thinned layer of prerinse liquid near the edge bevel area of the rotating wafer.

22. An apparatus for removing unwanted metal deposited on an edge bevel area of a semiconductor wafer, the apparatus comprising:
a process chamber;
a wafer chuck for supporting and rotating the wafer during removal of the edge bevel area;
a nozzle for delivering a prerinse liquid to the wafer;
a nozzle for delivering a liquid etchant to the wafer;
a radiative heater; and
a controller comprising:
program instructions for rotating the wafer;
program instructions for prerinsing the wafer using the prerinse liquid;
program instructions for thinning a layer of the prerinse liquid by heating the layer of the prerinse liquid using radiative heat without drying the wafer; and
program instructions for delivering a stream of liquid etchant into the thinned layer of prerinse liquid near the edge bevel area of the rotating wafer.

Assignees

• Novellus Systems Inc

Inventors

• Ganesan Kousik
• Ghongadi Shantinath
• Majid Tariq
• Labrie Aaron
• Mayer Steven T

Classifications

• H10P72/7624

  characterised by the mechanical construction of the susceptor, stage or support · CPC title

• H10P72/7611

  characterised by edge profile or support profile · CPC title

• H10P72/3304

  characterised by movements or sequence of movements of transfer devices · CPC title

• H10P70/56

  Cleaning of wafer backside · CPC title

• H10P70/54

  Cleaning of wafer edges · CPC title