Method of removing oxide layer and semiconductor manufacturing apparatus for removing oxide layer

• US 7,488,688 B2
• Filed: 11/29/2004
• Issued: 02/10/2009
• Est. Priority Date: 10/25/1999
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Kwang-wook, Lee, Kun-tack, Chang, Kyu-whan, Lee, Moon-hee, Park, Im-soo, Chung, Seung-pil, Lee, Sun-jung
• Primary Examiner(s): Hendricks; Keith D.
• Assistant Examiner(s): GEORGE, PATRICIA ANN
• Application Number:
  US10/997,902
• Publication Number:
  US 20050087893A1
• Time in Patent Office: 1,534 Days
• Field of Search: 414/217, 438/680, 438/706, 156/345.31, 118/719
• US Class Current: 438/706
• CPC Class Codes: H01L 21/02057 Cleaning during device manufacture
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A method for removing an oxide layer such as a natural oxide layer and a semiconductor manufacturing apparatus which uses the method to remove the oxide layer. A vertically movable susceptor is installed at the lower portion in a processing chamber and a silicon wafer is loaded onto the susceptor when it is at the lower portion of the processing chamber. The air is exhausted from the processing chamber to form a vacuum condition therein. A hydrogen gas in a plasma state and a fluorine-containing gas are supplied into the processing chamber to induce a chemical reaction with the oxide layer on the silicon wafer, resulting in a reaction layer. Then, the susceptor is moved up to the upper portion of the processing chamber, to anneal the silicon wafer on the susceptor with a heater installed at the upper portion of the processing chamber, thus vaporizing the reaction layer. The vaporized reaction layer is exhausted out of the chamber. The oxide layer can be removed with a high selectivity while avoiding damage or contamination of the underlying layer.

Claims

1. A method of removing an oxide layer using a semiconductor manufacturing apparatus, comprising:

(a) placing a vertically movable susceptor at a lower portion of a processing chamber and loading a wafer onto the vertically movable susceptor;

(b) supplying a cooling water or cooling gas into a cooling line in the susceptor to adjust a temperature of the wafer;

(c) flowing a hydrogen gas in a plasma state and a fluorine-containing gas into the processing chamber to induce a chemical reaction with the oxide layer on the wafer;

(d) moving the susceptor up to an upper portion of the processing chamber;

(e) annealing the wafer mounted on the susceptor with a heater installed at the upper portion of the processing chamber to vaporize a byproduct resulting from the chemical reaction; and

(f) exhausting the vaporized byproduct out of the processing chamber.

2. The method of claim 1, wherein after the step (f), the susceptor is moved back to the lower portion of the chamber and steps (b) to (f) are repeated one or more times.

3. The method of claim 1, wherein during the supplying the hydrogen gas in a plasma state and the fluorine-containing gas into the processing chamber, the hydrogen gas and the fluorine-containing gas are mixed in a predetermined ratio, changed into a plasma state, and then supplied into the processing chamber.

4. The method of claim 1, wherein during the supplying the hydrogen gas in a plasma state and the fluorine-containing gas into the processing chamber, the hydrogen gas is supplied in a plasma state into the processing chamber and the fluorine-containing gas is supplied in a non-plasma state into the processing chamber.

5. The method of claim 1, wherein the fluorine-containing gas is selected from the group consisting of NF3, SF6 and ClF3.

6. The method of claim 1, wherein the mixing ratio of the fluorine-containing gas to the hydrogen gas is in a range of 0.1:

1 to 100;

1 by volume.

7. The method of claim 1, wherein the gas mixture containing the hydrogen gas and the fluorine-containing gas in a predetermined ratio is supplied in a plasma state into the processing chamber together with a nitrogen gas (N2) and an argon gas (Ar).

8. The method of claim 1, wherein annealing the wafer is carried out using one of a lamp and laser.

9. The method of claim 8, wherein the laser is selecting from a group consisting of a neodymium (Nd)-YAG laser, a carbon dioxide (CO₂) laser, and an eximer laser.

10. A method of forming a dual gate oxide layer for a semiconductor device using a method of removing an oxide layer, comprising:

(a) forming a first gate oxide layer on a silicon wafer;

(b) forming etch barrier patterns on the first gate oxide layer;

(c) repeating the steps of;

placing a vertically movable susceptor at the lower portion of a processing chamber and loading the wafer onto the vertically movable susceptor placed at the lower portion of the processing chamber;

flowing a hydrogen gas in a plasma state and a fluorine-containing gas into the processing chamber to induce a chemical reaction with the first gate oxide layer exposed between the etch barrier patterns;

moving the susceptor up to an upper portion of the processing chamber; and

annealing the wafer mounted on the susceptor with a heater installed at the upper portion of the processing chamber to vaporize a byproduct resulting from the chemical reaction, until the first gate oxide layer exposed between the etch barrier patterns is completely removed;

(d) removing the etch barrier patterns;

(e) chemically treating the surface of the wafer with a solution to remove organic particles which may be present on the wafer surface, and performing the step (c) to remove a natural oxide layer resulting from the step (d) and the chemical treatment; and

(f) forming a second gate oxide layer on the structure obtained in the step (e).

11. The method of claim 10, wherein the etch barrier patterns are photoresist patterns covering a region of the first gate oxide layer to be the dual gate oxide layer.

12. A method of removing an oxide layer using the semiconductor manufacturing apparatus, the method comprising:

(a) loading a wafer onto a susceptor in a loading/unloading and post-processing module installed on a rotary plate of a processing chamber;

(b) operating a rotary motor installed at the center of the rotary plate to move the susceptor into a lower portion of a downflowing chamber in a downflowing module;

(c) moving the downflowing chamber down so that it contacts with the susceptor and the downflowing chamber thereby forming an air tight seal;

(d) supplying a hydrogen gas in a plasma state and a fluorine-containing gas into the downflowing chamber to induce a chemical reaction with the oxide layer on the wafer;

(e) moving the downflowing chamber up to an upper portion of the downflowing module apart from the susceptor, and moving the susceptor into the lower portion of an annealing chamber in an annealing module;

(f) moving the annealing chamber down so that is contacts with the rotary plate and the annealing chamber thereby forming an air tight seal;

(g) annealing the wafer with a heater installed at the upper portion of the annealing chamber to vaporize a byproduct resulting from the chemical reaction between the reactions gas and the oxide layer on the wafer; and

(h) exhausting the vaporized byproduct out of the annealing chamber.

13. The method of claim 12, after the step (f) further comprising:

moving the annealing chamber up to the upper portion of the annealing module apart from the susceptor;

moving the susceptor into the lower portion of a loading/unloading and post-processing chamber in the loading/unloading and post-processing module;

moving the loading/unloading and post-processing chamber down so that it contacts with the susceptor and the loading/unloading and post-processing chamber is made airtight; and

post-treating the wafer with the hydrogen gas.

14. The method of claim 12, wherein the steps (b) to (h) are sequentially repeated one or more times.

15. The method of claim 12, wherein the fluorine-containing gas is one selected from the group consisting of NF3, SF6 and ClF3.

16. The method of claim 12, wherein the mixing ratio of the fluorine-containing gas to the hydrogen gas is in the range of 0.1:

1 to 100;

1 by volume.

17. The method of claim 12, wherein the heater is one of a lamp and a laser.

18. A method of forming a dual gate oxide layer for a semiconductor device using the method of removing an oxide layer, comprising the steps of:

(a) forming a first gate oxide layer on a silicon wafer;

(b) forming etch barrier patterns on the first gate oxide layer;

(c) repeating the steps of;

flowing a hydrogen gas in a plasma state and a fluorine-containing gas into the processing chamber to induce a chemical reaction with the first gate oxide layer exposed between the etch barrier patterns; and

annealing the wafer to vaporize the byproduct resulting from the chemical reaction, until the first gate oxide layer exposed between the etch barrier patterns is completely removed;

(d) removing the etch barrier patterns;

(e) chemically treating the surface of the wafer with a solution to remove organic particles which may be present on the wafer surface;

(f) performing the step (c) to remove a natural oxide layer resulting from the steps (d) and (e); and

(g) forming a second gate oxide layer on the structure obtained in the step (f).

19. The method of claim 18, wherein the etch barrier patterns are photoresist patterns covering a region of the first gate oxide layer to be the dual gate oxide layer.