Etching processes used in MEMS production

• US 8,323,516 B2
• Filed: 09/12/2008
• Issued: 12/04/2012
• Est. Priority Date: 09/14/2007
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Bita, Ion, Gousev, Evgeni, Londergan, Ana, Yan, Xiaoming
• Primary Examiner(s): Vinh, Lan
• Assistant Examiner(s): ANGADI, MAKI A
• Application Number:
  US12/210,042
• Publication Number:
  US 20090101623A1
• Time in Patent Office: 1,544 Days
• Field of Search: 216/13, 216/37, 438/51, 438/52, 438/113, 438/464, 359/245, 359/254, 359/291
• US Class Current: 216/13
• 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:

providing an unreleased electronic device within an etch chamber, wherein the unreleased electronic device comprises;

a sacrificial layer; and

one or more light-transmissive layers adjacent a first side of the sacrificial layer;

performing an initial etch through a portion of the sacrificial layer, wherein the initial etch exposes at least a portion of the one or more light-transmissive layers;

releasing a gaseous etchant precursor into the etch chamber; and

physically exciting the gaseous etchant precursor by exposing the gaseous etchant precursor to UV light through the one or more light-transmissive layers so as to form a chemically active species capable of etching a remaining portion of the sacrificial layer.

2. The method of claim 1, wherein physically exciting the gaseous etchant precursor does not comprise performing a plasma etch.

3. The method of claim 1, additionally comprising releasing a homogenous catalyst into the etch chamber.

4. The method of claim 3, wherein the homogenous catalyst comprises Kr or Xe.

5. The method of claim 1, wherein the gaseous etchant comprises OF₂.

6. The method of claim 1, wherein the gaseous etchant comprises a derivative of OF₂.

7. The method of claim 1, wherein the electronic device comprises a MEMS device.

8. The method of claim 1, wherein the electronic device comprises an interferometric modulator.

9. A method of fabricating an electronic device, comprising:

providing a partially fabricated electronic device within a process chamber, the partially fabricated electronic device comprising an exposed portion of a layer to be etched;

introducing an gaseous etchant into the process chamber, wherein the etchant can be activated by exposure to ultraviolet radiation; and

exposing a portion of the layer to be etched to radiation from an ultraviolet laser, wherein exposure to the ultraviolet laser activates the gaseous etchant.

10. The method of claim 9, additionally comprising introducing a radical scavenger into the process chamber prior to exposing the portion of the layer to be etched to ultraviolet radiation.

11. The method of claim 9, wherein the gaseous etchant is configured to dissociate upon exposure to ultraviolet radiation.

12. The method of claim 9, wherein the gaseous etchant is configured to be excited to a chemically active state upon exposure to ultraviolet radiation.

13. A method of fabricating an electronic device, comprising:

providing an electronic device within a process chamber, wherein the electronic device comprises a layer to be etched;

providing a gaseous precursor mixture, wherein the gaseous precursor mixture comprises fluorine and a noble gas;

exposing the gaseous precursor mixture to ultraviolet radiation to form a noble gas fluoride; and

exposing the electronic device to the noble gas fluoride.

14. The method of claim 13, wherein the noble gas comprises Xe.

15. The method of claim 13, wherein the noble gas comprises Kr.

16. The method of claim 13, wherein the gaseous etchant precursor is exposed to UV radiation within a separate chamber in fluid communication with the process chamber, and wherein exposing the electronic device to the noble gas fluoride comprises releasing the noble gas fluoride from the separate chamber into the process chamber.

17. The method of claim 13, wherein the gaseous precursor mixture is released into the process chamber, and wherein exposure to ultraviolet radiation generates the noble gas fluoride in situ.

18. A method of fabricating an electronic device, comprising:

providing an electronic device within a process chamber, wherein the electronic device comprises a layer to be etched;

releasing an etchant into the process chamber, wherein the etchant comprises a noble gas fluorine, the etchant reacting with the layer to be etched to form elemental noble gas as a byproduct;

releasing fluorine into the process chamber; and

exposing the fluorine and the elemental noble gas to ultraviolet radiation to generate additional noble gas fluorine.

19. The method of claim 18, wherein the noble gas fluorine comprises XeF₂.

20. The method of claim 18, wherein the electronic device comprises one or more light-transmissive layers adjacent a first side of the layer to be etched, and wherein at least a portion of the fluorine and the noble gas are exposed to the ultraviolet radiation through the one or more light-transmissive layers.

21. The method of claim 18, wherein the electronic device comprises a MEMS device, and the layer to be etched comprises a sacrificial layer.