Fluorinated solvent compositions containing hydrogen fluoride

• US 6,492,309 B1
• Filed: 10/27/2000
• Issued: 12/10/2002
• Est. Priority Date: 03/31/2000
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Weaver, Billy L., Theiss, Silva K., Parent, Michael J., Behr, Frederick E., Zazzera, Lawrence A., Rajtar, Paul E.
• Primary Examiner(s): Webb, Gregory E.
• Application Number:
  US09/698,690
• Time in Patent Office: 774 Days
• Field of Search: 134/1.1, 134/1.3, 134/2, 134/3, 216/37, 216/57, 216/66, 252/79.4, 252/79.3, 438/265, 438/305, 438/385, 438/396, 438/622, 438/623, 438/625, 438/695, 438/711, 438/718, 438/723, 510/175, 510/176
• US Class Current: 510/175
• CPC Class Codes: C11D 2111/22 Electronic devices, e.g. PCBs or semiconductors
• CPC Class Codes: C11D 7/08 Acids
• CPC Class Codes: C11D 7/5018 Halogenated solvents
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes

Abstract

A homogeneous compositions containing a fluorinated solvent, hydrogen fluoride, and an optional co-solvent, and the use of these compositions for etching of microelectromechanical devices is described.

Claims

1. A method of etching and releasing a microelectromechanical device comprising contacting said device with an essentially anhydrous cleaning composition comprising 88 weight percent or more of a fluorinated solvent, from 0.005 to 2 weight percent of hydrogen fluoride or complex thereof, and 30 weight percent or less of a co-solvent.

2. The method of claim 1 further comprising the step of separating the processed substrate from said composition.

3. The method of claim 1 wherein said composition etches said substrate and releases the microelectromechanical device.

4. The method of claim 1 wherein said composition contacts said substrate for a time sufficient to achieve a predetermined degree of etching.

5. The method of claim 2 further comprising the step of quenching said etching by additional an excess amount of alcohol.

6. The method claim 1 having an etch rate of at least 28 angstroms/minute.

7. The method of claim 1 further comprising the step of rinsing said substrate with a fluorinated liquid.

8. The method of claim 1 wherein said device is a micro mirror.

9. The method of claim 1 wherein said device is etched and released from a microelectromechanical device encased in a sacrificial layer.

15. A microelectromechanical device prepared by the method of claim 1.

10. A method for preparing a microelectromechanical devices comprising the steps of;

providing a silicon wafer containing an unreleased device;

contacting the wafer with an essentially anhydrous cleaning composition comprising 88 weight percent or more of a fluorinated solvent, from 0.005 to 2 weight percent of hydrogen fluoride or complex thereof, and 30 weight percent or less of a co-solvent for a time sufficient to etch and release said device.

11. The process of claim 10 wherein said device has a critical etch distance of 40 micrometers or more.

12. The process of claim 11 wherein said critical etch distance is 40 to 400 micrometers.

13. The method of claim 10 wherein said microelectromechanical devices has no etch holes.

14. The method of claim 13 wherein said co-solvent is selected from the group consisting of aliphatic and aromatic hydrocarbons, ethers, polyethers, carboxylic acids, primary and secondary alcohols, and hydrochlorocarbons.

16. The method of claim 10 wherein said unreleased microelectromechanical device has a critical etch distance of 40 to 400 micrometers.

17. The fluorinated solvent of claim 14 selected from CF₃CFHCFHCF₂CF₃, C₅F₁₁H, C₆F₁₃H, CF₃CH₂CF₂H, CF₃CF₂CH₂CH₂F, CHF₂CF₂CF₂CHF₂, 1,2-dihydroperfluorocyclopentane and 1,1,2-trihydroperfluorocyclopentane.