Micro-support structures

• US 20040001264A1
• Filed: 06/28/2002
• Published: 01/01/2004
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Yeh, Richard, Amm, David T., Hunter, James, Gudeman, Christopher
• Granted Patent: US 6,908,201 B2
• Time in Patent Office: Days
• US Class Current: 359/883
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81C 1/00111 Tips, pillars, i.e. raised structures microneedles A61M37/0015
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements

Abstract

A MEM device in accordance with the invention comprises one or more movable micro-structures which are preferably ribbon structures or cantilever structures. The ribbon structures or cantilever structures are preferably coupled to a substrate structure through one or more support regions comprising a plurality of anchor support features and a plurality of post support features. The MEM device is preferably an optical MEM device with a plurality of movable ribbon structures each being supported by opposing ends through support regions each comprising a plurality of anchor support features and a plurality of post support features. In accordance with the method of the embodiments, the positions of the anchor and post support features, the number of anchor and support features and the spacings between the support features can selected during fabrication of the device to determine an operating condition of the MEM device.

Claims

1. A micro-device comprising an elongated micro-structure coupled to a substrate by at least one end through a securing region comprising sets of securing features arranged laterally along the at least one end.

2. The micro-device of claim 1, wherein the sets of securing features comprise anchor features and post features.

3. The micro-device of claim 1, wherein the anchor features and the post features are arranged in parallel rows laterally along the at least one end.

4. The micro-device of claim 1, wherein the elongated micro-structure is a ribbon structure having a length in a range of 50 to 1000 microns and a width in a range of 4.0 to 40 microns.

5. The micro-device of claim 1, wherein the sets of securing features comprise silicon nitride.

6. The micro-device of claim 5, wherein the micro-structure comprises silicon nitride and is monolithic with the sets of securing features.

7. The micro-device of claim 1, wherein the micro-structure comprises a silicon nitride layer with a thickness in a range of 200 to 2000 Angstroms.

8. The micro-device of claim 7, wherein the micro-structure further comprises a reflective top-layer on at least a portion of the silicon nitride layer, the reflective layer having a thickness in a range of 250 to 1500 Angstroms.

9. The micro-device of claim 1, wherein the substrate comprises silicon.

10. A micro-structure comprising an elongated ribbon coupled to a substrate through at least two securing regions, each securing region comprising a plurality of larger anchor features arranged in a row along a width of the elongated ribbon and a plurality of smaller anchor features arranged in a parallel row along the width of the ribbon.

11. The micro-structure of claim 10, wherein a portion of the elongated ribbon is configured to move up and down relative to the substrate structure.

12. The micro-structure of claim 11, wherein the elongated ribbon comprises silicon nitride with a reflective top-layer.

13. The micro-structure of claim 10, wherein the at least two securing regions are arranged near the ends of the ribbon.

14. A method of making a micro-device comprising:

a. forming rows of support regions in a sacrificial layer, the support regions comprising posterior anchor features and interior post features, the posterior anchor features and interior post features being separated by a distance;

b. forming parallel ribbon structures over the rows of support regions and extending between the rows of support regions; and

c. removing at least a portion of the sacrificial layer between the rows of support regions and under the ribbon structures to form suspended ribbon structures.

15. The method of claim 14, wherein the suspended ribbon structures are under tensions of 1.5 Gpa or more.

16. The method of claim 14, wherein the ribbon features each span a plurality of posterior anchor features and interior post features from each of the rows of support regions.

17. The method of claim 14, wherein the step of forming the support regions comprises etching the sacrificial layer through one or more masks.

18. The method of claim 14, wherein the suspended ribbon structures are in a range of 50 to 1000 microns long.

19. The method of claim 14, wherein the suspended ribbon structures are in a range of 4.0 to 40 microns wide.

20. The method of claim 14, wherein the step of forming the ribbon features comprises depositing a continuous device layer with a thickness in a range of 500 to 2,000 Angstroms over the sacrificial layer.

21. The method of claim 20, wherein the continuous device layer is a silicon nitride layer.

22. A device comprising a plurality of ribbons suspended over a substrate, wherein each of the ribbons are suspended over the substrate by opposing ends through a plurality of anchor features and a plurality of post features.

23. The device of claim 22, wherein the ribbons are in a range of 4.0 to 40 microns wide and 50 to 1000 microns long.

24. The device of claim 22, wherein the ribbons comprise layers of silicon nitride that are in a range of 500 to 2000 Angstroms thick.

25. The device of claim 24, wherein the ribbons comprise a top-layer of aluminum with a thickness in a range of 250 to 1500 Angstroms thick.

26. The device of claim 22, wherein at least a portion of the ribbons are configured to move relative to the substrate to modulate a light source having a wavelength in a range of 300 to 3000 nanometers.

27. A method of fabricating an optical MEM device comprising:

a. depositing a layer of poly-silicon on a suitable substrate;

b. etching the poly-silicon with a first set of anchor and post dimples;

c. depositing a device layer over the poly-silicon layer and the dimples to from a first set of anchor and post features which are coupled to the substrate;

d. dividing the device layer into ribbons such that two or more anchor and post features from the first set of anchor and post features are coupled to each of the ends of the ribbons; and

e. etching the poly-silicon layer to release the ribbons.

28. The method of claim 27, wherein the substrate comprises a layer on silicon oxide.

29. The method of claim 27, wherein the device layer comprises silicon nitride.

30. The method of claim 27, wherein the anchor features have cross-sectional dimensions in a range of 5.0 to 20 microns and the post features have cross-sectional dimensions in a range of 0.5 to 5.0 microns.

31. The method of claim 27, wherein the step of dividing the device layer into ribbons comprises cutting the device layer into the ribbons using a reactive ion etch process.

32. The method of claim 27, wherein the first set of anchor and post features are in parallel rows.

33. The method of claim 27, wherein the anchor features of the first set of anchor and post features are in row and the post features are staggered.

34. The method of claim 27, further comprise etching the poly-silicon with a second set of anchor and post dimples before depositing the device layer and depositing the device layer over both of the first set and the second of anchor and post dimples to form a first and second set of anchor and post features and wherein the device layer is divided into ribbons such that two or more anchor and post features from both of the first set and the second set are coupled each of the ribbons.

35. The method of claim 34, wherein the first set of anchor and post features and the second set anchor and post features are coupled each of the ribbons at opposite ends of the ribbons.