Method for the wet-chemical treatment of a semiconductor wafer

• US 8,070,882 B2
• Filed: 12/03/2008
• Issued: 12/06/2011
• Est. Priority Date: 12/05/2007
• Status: Active Grant

• Current Assignee: Siltronic AG (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Original Assignee: Siltronic AG (Dr. Alexander Wacker Familiengesellschaft Mit Beschrã¤Nkter Haftung)
• Inventors: Schwab, Guenter, Zapilko, Clemens, Buschhardt, Thomas, Feijoo, Diego, Haibara, Teruo, Mori, Yoshihiro
• Primary Examiner(s): Kornakov, Michael
• Assistant Examiner(s): Whatley, Katelyn
• Application Number:
  US12/326,969
• Publication Number:
  US 20090145457A1
• Time in Patent Office: 1,098 Days
• Field of Search: 134/1.3, 134/2, 134/3, 134/4
• US Class Current: 134/2
• CPC Class Codes: B08B 3/10 with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
• CPC Class Codes: H01L 21/02052 Wet cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/02057 Cleaning during device manufacture

Abstract

A method for the wet-chemical treatment of a semiconductor wafer involves: a) rotating a semiconductor wafer; b) applying a cleaning liquid comprising gas bubbles having a diameter of 100 μm or less to the rotating wafer such that a liquid film forms on the wafer; c) exposing the rotating semiconductor wafer to a gas atmosphere containing a reactive gas; and d) removing the liquid film from the wafer.

Claims

1. A method for the individual wet-chemical treatment of a semiconductor wafer, comprising:

a) rotating a semiconductor wafer;

b) distributing a cleaning liquid comprising gas bubbles having a diameter of 100 μ

m or less onto the surface of the rotating semiconductor wafer, such that a liquid film having a thickness of greater than or equal to 1 μ

m and less than or equal to 100 μ

m forms on the semiconductor wafer surface;

c) exposing the rotating semiconductor wafer and liquid film to a gas atmosphere containing a reactive gas, wherein the reactive gas diffuses through the gas space of the microbubbles in the liquid film from the gas atmosphere and contacts the wafer surface; and

d) removing the liquid film.

2. The method of claim 1, wherein the gas bubbles comprise a gas or a gas mixture of at least one gas selected from the group consisting of air, nitrogen, argon, helium, hydrogen, carbon dioxide, and ozone.

3. The method of claim 1, wherein the semiconductor wafer is rotated at a speed of 20-600 rpm.

4. The method of claim 1, wherein the liquid film has a thickness of 50-100 μ

m and the rotational speed of the semiconductor wafer is 50-300 rpm.

5. The method of claim 1, wherein the wet-chemical treatment of the semiconductor wafer in accordance with b) and c) is effected for 30-200 s.

6. The method of claim 5, wherein the wet-chemical treatment of the semiconductor wafer is effected for 30-60 s.

7. The method of claim 1, wherein the liquid film is removed in step d) by rinsing with ultrapure water, ozone-containing ultrapure water, SCl solution or dilute hydrochloric acid.

8. The method of claim 1, wherein the semiconductor wafer is a silicon wafer, an SOI wafer, a GeOI wafer or a silicon wafer having a silicon-germanium layer.

9. The method of claim 1, wherein the rotating semiconductor wafer is exposed to a gas atmosphere of at least one reactive gas selected from the group consisting of ozone, ammonia, hydrogen fluoride, hydrogen chloride, hydrogen, carbon dioxide, and mixtures of these gases with oxygen or air.

10. The method of claim 9, wherein the gas atmosphere comprises an ozone/oxygen mixture or an ozone/oxygen/nitrogen mixture having an ozone concentration of 100-300 g/m³ (stp) (gram per standard cubic meter).

11. The method of claim 1, wherein the cleaning liquid comprises hydrogen fluoride or hydrogen chloride or a combination of hydrogen fluoride and hydrogen chloride.

12. The method of claim 11, wherein the cleaning liquid contains hydrogen fluoride with a concentration of 0.02-2%.

13. The method of claim 1, wherein the cleaning liquid comprises at least one alkaline component selected from the group consisting of ammonia, tetramethylammonium hydroxide, organic amines, alkali metal hydroxides, and alkali metal carbonates, and wherein the rotating semiconductor wafer is exposed to an ozone atmosphere.

14. The method of claim 1, wherein the cleaning liquid comprises deionized water and hydrogen gas bubbles and the rotating semiconductor wafer is exposed to a gas atmosphere of hydrogen fluoride.

15. The method of claim 1, wherein the cleaning liquid comprises dilute hydrofluoric acid, gas bubbles composed of at least one inert gas selected from the group consisting of air, nitrogen and argon, and wherein the rotating semiconductor wafer is exposed to an atmosphere comprising hydrogen.

16. The method of claim 1, wherein at least one amphiphilic substance selected from the group consisting of ionic surfactants, nonionic surfactants, fatty acids, fatty alcohols and ethylene glycols is added to the cleaning liquid.

17. A method for the individual wet-chemical treatment of a semiconductor wafer, comprising placing the semiconductor wafer into a process chamber containing a gas atmosphere;

supplying a liquid containing microbubbles having a diameter of 100 μ

m or less and distributing said liquid onto the surface of the wafer;

rotating the wafer at a rotational speed, the rotational speed causing the liquid to form a liquid film having a film thickness of 1 to 100 μ

m on the surface of the wafer, the thickness of the film being regulatable by adjusting the rotational speed of the wafer, the film being exposed to the gas atmosphere of the reaction chamber;

supplying a reactive gas to the gas atmosphere in the reaction chamber such that the reactive gas diffuses through the gas space of the microbubbles in the liquid film from the gas atmosphere and contacts the wafer surface; and

removing the liquid film from the wafer.

18. The method of claim 17, wherein the rotational speed of the wafer is between 50 and 300 rpm.

19. The method of claim 17 wherein the step of distributing comprises spraying the liquid onto the rotating wafer.