ETCHING PROCESSES USED IN MEMS PRODUCTION

• US 20090074646A1
• Filed: 09/12/2008
• Published: 03/19/2009
• Est. Priority Date: 09/14/2007
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sasagawa, Teruo, Yan, Xiaoming
• Application Number:
  US12/210,138
• Publication Number:
  US 20090074646A1
• Time in Patent Office: Days
• US Class Current: 423/325
• CPC Class Codes: B01D 2257/11 Noble gases
• CPC Class Codes: B01D 2257/2027 Fluorine
• CPC Class Codes: B01D 53/002 by condensation
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/32135 by vapour etching only

Abstract

The efficiency of an etching process may be increased in various ways, and the cost of an etching process may be decreased. Unused etchant may be isolated and recirculated during the etching process. Etching byproducts may be collected and removed from the etching system during the etching process. Components of the etchant may be isolated and used to general additional etchant. Either or both of the etchant or the layers being etched may also be optimized for a particular etching process.

Claims

1. A method of fabricating an electronic device comprising a sacrificial material, wherein the method comprises:

providing an electronic device comprising a sacrificial material, the sacrificial material comprising a compound of the general formula M_pX_q, wherein M is selected from Mo, W, Si, and Ge;

X is selected from Cl, F, O, N, and Si, wherein M is different from X, wherein p and q are in the range of 1 to 6, and wherein a molar volume of M_pX_q for a given M is greater than a molar volume of M; and

exposing the electronic device to an etchant.

2. The method of claim 1, wherein the etchant comprises a noble gas fluoride.

3. The method of claim 2, wherein the etchant further comprises O₂.

4. The method of claim 2, wherein the etchant comprises XeF₂.

5. The method of claim 4, wherein for a given M, a molar unit of M_pX_q is etchable by a smaller volume of XeF₂ than a molar unit of M.

6. The method of claim 1, wherein the sacrificial material comprises MoF₃.

7. The method of claim 1, wherein the sacrificial material comprises MoF₄.

8. The method of claim 1, wherein the sacrificial material comprises MoF₆.

9. The method of claim 1, wherein the sacrificial material comprises MoN.

10. The method of claim 1, wherein the sacrificial material comprises MoSi₂.

11. The method of claim 1, wherein the sacrificial material comprises MoO₂.

12. The method of claim 1, wherein the sacrificial material comprises MoO₃.

13. The method of claim 1, wherein the sacrificial material comprises MoCl₃.

14. The method of claim 1, wherein the sacrificial material comprises WN₂.

15. The method of claim 1, wherein the sacrificial material comprises WCl₄.

16. The method of claim 1, wherein the sacrificial material comprises WO₂.

17. The method of claim 1, wherein the sacrificial material comprises WF₄.

18. The method of claim 1, wherein the sacrificial material comprises SiO.

19. The method of claim 1, wherein the sacrificial material comprises Si₃N₄.

20. The method of claim 1, wherein the sacrificial material comprises GeF₂.

21. A partially fabricated electronic device comprising a sacrificial material, the sacrificial material comprising a compound of the general formula M_pX_q, wherein M is selected from Mo, W, Si, and Ge;

X is selected from Cl, F, O, N, and Si, wherein M is different from X, wherein p and q are in the range of 1 to 6, and wherein a molar volume of M_pX_q for a given M is greater than a molar volume of M.

22. The device of claim 21, wherein for a given M, a molar unit of M_pX_q is etchable by a smaller volume of XeF₂ than a molar unit of M.

23. An etching device for use in fabricating a MEMS device, the etching device comprising:

a storage system configured to store an etchant, wherein the etchant comprises XeF₂ and O₂;

an etching chamber configured to retain a MEMS device during an etching process, wherein the etching chamber is in fluid communication with the storage system; and

a cold trap in fluid communication with the etching chamber, wherein the cold trap is configured to remove a byproduct of the etching process.

24. The etching device of claim 23, wherein the storage system comprises:

a first storage chamber configured to store XeF₂;

a second storage chamber configured to store O₂; and

a mixing chamber in fluid communication with both of said first and second storage chambers.

25. The etching device of claim 23, additionally comprising a purge storage chamber, wherein the purge storage chamber is configured to store a purge gas, and wherein the purge storage chamber is in fluid communication with the etching chamber.

26. The etching device of claim 23, additionally comprising:

an exhaust pump in fluid communication with the etching chamber, wherein the exhaust pump is configured to remove process gases from the etching chamber; and

a size discriminator configured to separate components from the process gases.