Method to address carbon incorporation in an interpoly oxide

• US 7,824,505 B2
• Filed: 07/26/2006
• Issued: 11/02/2010
• Est. Priority Date: 09/28/2004
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Rana, Niraj, Shea, Kevin R.
• Primary Examiner(s): Cleveland; Michael
• Assistant Examiner(s): BLAN, NICOLE R
• Application Number:
  US11/493,053
• Publication Number:
  US 20060260646A1
• Time in Patent Office: 1,560 Days
• Field of Search: None
• US Class Current: 134/28
• CPC Class Codes: B08B 3/08 the liquid having chemical or dissolving effect substances used, see the relevant classes
• CPC Class Codes: C23F 1/32 Alkaline compositions C23F1/42 takes precedence
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes

Abstract

A method of removing a mask and addressing interfacial carbon chemisorbed in a semiconductor wafer starts with placing the semiconductor wafer into a dry strip chamber. The dry stripping process is performed to remove the mask on the semiconductor wafer. The semiconductor wafer is then subjected to a cleaning solution to perform a cleaning process to remove particles on the surface of the semiconductor wafer and to address the interfacial carbon. The cleaning solution being either water containing ozone (O₃) and ammonia (NH₃), or a solution of hot phosphoric acid (H₃PO₄).

Claims

1. A method to clean a semiconductive device, the semiconductive device comprises a substrate, a device structure formed over the substrate, said device structure comprising a polysilicon layer, and an amorphous carbon mask formed over the device structure, wherein the method comprises:

removing said amorphous carbon mask from said device structure by dry stripping;

wetting said semiconductive device with a first liquid solution at a first temperature for a first period of time after the removal of said amorphous carbon mask, said first liquid solution having an etch-rate of less than 1 A/min for polysilicon and an etch-rate of less than 1.5 A/min for undensified TEOS, said first liquid solution consisting of phosphoric acid (H₃PO₄), and said first liquid solution effective in removing interfacial carbon from said polysilicon layer of said device structure formed over the substrate;

wetting said semiconductive device with a second liquid solution comprising deionized water after expiration of said first period of time for a second period of time; and

spin-drying said semiconductive device after expiration of said second period of time.

2. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive device with first liquid solution.

3. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive device with said first liquid solution, wherein said first rate is a spin rate ranging from 50 to 2500 revolutions per minute.

4. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive with said first liquid solution, and spinning said semiconductive device at a second rate after expiration of said first period of time.

5. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive device with said first liquid solution, and spinning said semiconductive device at a second rate after expiration of said first period of time, wherein said second rate is a spin rate ranging from 50 to 2500 revolutions per minute.

6. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive device with said first liquid solution wherein said first rate is a spin rate ranging from 50 to 2500 revolutions per minute;

and spinning said semiconductive device at a second rate after expiration of said first period of time, wherein said second rate is a spin rate ranging from 50 to 2500 revolutions per minute.

7. The method of claim 1 where said first period of time has a duration ranging from about 2 minutes to about 20 minutes.

8. The method of claim 1 where said second period of time has a duration ranging from about 20 seconds to about 300 seconds.

9. The method of claim 1 wherein said first temperature is a temperature ranging from about 50°

C. to about 95°

C.

10. The method of claim 1 wherein said first temperature is a temperature in the range from about 160°

C. to about 180°

C.

11. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive device with said first liquid solution, wherein said first rate is a spin rate ranging from 50 to 2500 revolutions per minute and said first period of time has a duration ranging from about 2 minutes to about 20 minutes;

and spinning said semiconductive device at a second rate after expiration of said first period of time, wherein said second rate is a spin rate ranging from 50 to 2500 revolutions per minute, and said second period of time has a duration ranging from about 20 seconds to about 300 seconds.

12. The method of claim 1 wherein said semiconductive device is spin-drying at a spin rate ranging from about 2000 to about 2500 rpm for a duration ranging from about 10 to about 20 seconds.

13. The method of claim 1 further comprises spinning said semiconductive device at a first rate when wetting said semiconductive device with said first liquid solution, wherein said first rate is a spin rate ranging from 50 to 2500 revolutions per minute and said first period of time has a duration ranging from about 2 minutes to about 20 minutes;

and spinning said semiconductive device at a second rate after expiration of said first period of time, wherein said second rate is a spin rate ranging from 50 to 2500 revolutions per minute, and said second period of time has a duration ranging from about 20 seconds to about 300 seconds, and wherein said semiconductive device is spin-drying at a spin rate ranging from about 2000 to about 2500 rpm for a duration ranging from about 10 to about 20 seconds.

14. The method of claim 1 where said wetting said semiconductive device with said first liquid solution comprises immersing said semiconductive device in a bath consisting of the first liquid solution hot phosphoric acid for about 8 to about 12 minutes, said bath having a temperature of from about 160°

C. to about 180°

C.

15. The method of claim 1 further comprises using a standard cleaning solution (SC-1) after said wetting semiconductive device with said first and second liquid solutions to remove particles form a surface of said device structure.

16. The method of claim 1 further comprises using a 5:

1;

1 solution of water, hydrogen peroxide (H₂O₂), and ammonium hydroxide (NH₄OH) to remove particles from a surface of said device after wetting said semiconductive device with said first and second liquid solutions.

17. The method of claim 1 further comprises using a third liquid solution comprising a standard cleaning (SC-1) solution after said wetting said semiconductive device with said first and second liquid solutions to remove particles from a surface of said device structure, and using a fourth liquid solution to remove a residual amount amounts of said SC-1 solution.