Method of high pressure treatment

• US 20040103922A1
• Filed: 10/01/2003
• Published: 06/03/2004
• Est. Priority Date: 12/03/2001
• Status: Active Grant

• Current Assignee: Klaus Schmidt
• Original Assignee: Klaus Schmidt
• Inventors: Masuda, Kaoru, Inoue, Yoichi, Iijima, Katsuyuki
• Granted Patent: US 6,962,161 B2
• Time in Patent Office: Days
• US Class Current: 134/26
• CPC Class Codes: B08B 7/0021 by liquid gases or supercritical fluids
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/31133 by chemical means
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

In a high pressure processing method for removing an unnecessary substrate on the surface of the surface of a workpiece by bringing it into contact with supercritical carbon dioxide and additives in a high-pressure chamber, removing the unnecessary substance on the workpiece, first rinsing and second rinsing are performed under a substantially same pressure with continuous flowing of supercritical carbon dioxide.

Claims

1. A high-pressure processing method for removing an unnecessary substance on the surface of a workpiece by bringing the surface of the workpiece into contact with supercritical carbon dioxide and additives in a high-pressure processing chamber, said method comprising the steps of:

sealing said high-pressure processing chamber after loading said workpiece in said high-pressure processing chamber;

pressurizing said high-pressure processing chamber with pressurized carbon dioxide supplied to said high-pressure processing chamber to a predetermined pressure and a predetermined temperature higher than the critical pressure and critical temperature thereof respectively;

dissolving said additives and a co-solvent in supercritical carbon dioxide by mixing said additives and said co-solvent with said supercritical carbon dioxide in the upstream of said high-pressure processing chamber;

removing an unnecessary substance on said workpiece while maintaining the inside of said high-pressure processing chamber higher than the critical pressure and critical temperature of carbon dioxide, by supplying continuously a predetermined amount of a mixture fluid of said additives, said co-solvent and said supercritical carbon dioxide to said high-pressure processing and ejecting a substantially equal amount of the high-pressure fluid to the predetermined supply amount from said high-pressure processing chamber;

obtaining a first rinse fluid in which said co-solvent is dissolved in said supercritical carbon dioxide, by stopping feed of said additives and mixing said co-solvent with said supercritical carbon dioxide in the upstream of said high-pressure processing chamber;

performing a first rinsing process for replacing the mixture fluid of said additives, said co-solvent and said supercritical carbon dioxide in said high-pressure processing chamber with said first rinse fluid while maintaining the inside of said high-pressure processing chamber higher than the critical pressure and critical temperature of carbon dioxide, by supplying continuously a predetermined amount of said first rinse fluid to said high-pressure processing chamber and ejecting a substantially equal amount of the high-pressure fluid to the predetermined supply amount from said high-pressure processing chamber;

performing a second rinsing process for replacing said first rinse fluid in said high-pressure processing chamber with said supercritical carbon dioxide while maintaining the inside of said high-pressure processing chamber higher than the critical pressure and critical temperature of carbon dioxide, by stopping supply of said co-solvent, supplying continuously only supercritical carbon dioxide by a predetermined amount to said high-pressure processing chamber and ejecting a substantially equal amount of the high-pressure fluid to the predetermined supply amount from the high-pressure processing chamber;

stopping feed of carbon dioxide to said high-temperature processing chamber;

decompressing said high-pressure processing chamber to atmospheric pressure; and

unloading said workpiece from said high-pressure processing chamber.

2. The high-pressure processing method as set forth in claim 1,

wherein said co-solvent is an aliphatic alcohol.

3. The high-pressure processing method as set forth in claim 2,

wherein, said co-solvent comprises at least one alcohol selected from a group consisting of aliphatic alcohols having 1 to 3 carbons.

4. The high-pressure processing method as set forth in claim 1,

wherein said additives contain a fluoride.

5. The high-pressure processing method as set forth in claim 4,

wherein said fluoride is a compound that contains a nitrogen atom and a hydrogen atom.

6. The high-pressure processing method as set forth in claim 1,

wherein a ratio of a total amount of said additives and said co-solvent is between 0.1 and 10 mass percent, to the combination of said additives, said co-solvent and said supercritical carbon dioxide.

7. The high-pressure processing method as set forth in claim 1,

wherein in the mixture fluid of said additives and said co-solvent is between 0.1 and 5 mass percent, to the combination of said additives, said co-solvent and said supercritical carbon dioxide.

8. A high-pressure processing method as set forth in claim 1, further including the step of,

supplying the combination of said additives, said co-solvent and said carbon dioxide, or the combination of said co-solvent and said carbon dioxide to said high pressure chamber, after mixing the combination mechanically.

9. A high-pressure processing method as set forth in claim 1, further including the step of,

supplying the combination of said additives, said co-solvent and said carbon dioxide, or the combination of said co-solvent and said carbon dioxide to said high pressure chamber, after mixing the combination and reheating.