HIGH REFLECTANCE TERAHERTZ MIRROR AND RELATED METHOD

• US 20100108891A1
• Filed: 10/30/2008
• Published: 05/06/2010
• Est. Priority Date: 10/30/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cox, James Allen, Higashi, Robert
• Granted Patent: US 8,198,590 B2
• Time in Patent Office: Days
• US Class Current: 250/341.800
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/3581 using far infrared light; using Terahertz radiation
• CPC Class Codes: G02B 5/0816 Multilayer mirrors, i.e. having two or more reflecting layers G02B5/0883, G02B5/0891 take precedence
• CPC Class Codes: H01S 3/08059 Constructional details of the reflector, e.g. shape mirrors in general G02B5/08; mountings for mirrors G02B7/18

Abstract

A method includes forming a plurality of mirror periods, stacking the mirror periods, and bonding the mirror periods together to form a high reflectance mirror. At least one of the mirror periods is formed by bonding a first semiconductor layer to a first side of a film layer (where the film layer is formed on a second semiconductor layer), forming an opening through the second semiconductor layer to expose the film layer, and cutting through the first semiconductor layer, the film layer, and the second semiconductor layer. The first semiconductor layer could include a high resistivity silicon wafer, the film layer could include an oxide film, and the second semiconductor layer could include a silicon wafer. The high resistivity silicon wafer could be approximately 110 μm thick, and the silicon wafer could be approximately 125 μm thick. The opening through the second semiconductor layer could be 1.25 cm to 1.75 cm in width.

Claims

1. A method comprising:

forming a plurality of mirror periods, wherein at least one of the mirror periods is formed by;

bonding a first semiconductor layer to a first side of a film layer, the film layer formed on a second semiconductor layer;

forming an opening through the second semiconductor layer to expose the film layer; and

cutting through the first semiconductor layer, the film layer, and the second semiconductor layer;

stacking the mirror periods; and

bonding the mirror periods together to form a high reflectance mirror.

2. The method of claim 1, wherein at least one of the mirror periods is formed further by:

depositing a photoresist layer over the first semiconductor layer, the photoresist layer including two vias; and

etching the first semiconductor layer through the vias to form street patterns in the first semiconductor layer.

3. The method of claim 2, wherein cutting through the first semiconductor layer, the film layer, and the second semiconductor layer comprises cutting along the street patterns in the first semiconductor layer.

4. The method of claim 1, wherein forming the opening through the second semiconductor layer comprises:

depositing a photoresist layer over the second semiconductor layer, the photoresist layer including a first open area; and

etching the second semiconductor layer through the first open area to form the opening.

5. The method of claim 4, wherein:

the photoresist layer further includes a second open area;

etching the second semiconductor layer forms a glue notch; and

bonding the plurality of mirror periods together comprises depositing a bonding material along the glue notches of the mirror periods.

6. The method of claim 1, wherein:

the first semiconductor layer comprises a high resistivity silicon wafer;

the film layer comprises an oxide film; and

the second semiconductor layer comprises a silicon wafer.

7. The method of claim 6, wherein:

the high resistivity silicon wafer is approximately 110 μ

m thick; and

the silicon wafer is approximately 125 μ

m thick.

8. The method of claim 1, wherein the opening through the second semiconductor layer is 1.25 cm to 1.75 cm in width.

9. The method of claim 1, further comprising:

a spacer layer formed under a bottom one of the stacked mirror periods.

10. The method of claim 1, wherein forming the opening through the second semiconductor layer comprises performing a deep reactive ion etch.

11. An apparatus comprising:

a plurality of mirror periods stacked and bonded together, each mirror period comprising a first semiconductor layer bonded to a first side of a film layer and a second semiconductor layer bonded to a second side of the film layer, the second semiconductor layer comprising an opening;

wherein the openings in at least some of the stacked mirror periods form cavities.

12. The apparatus of claim 11, wherein the first semiconductor layer in each mirror period has a high refractive index and material in the cavity of each mirror period has a low refractive index, giving the apparatus a high-index|low-index mirror period.

13. The apparatus of claim 11, wherein:

each mirror period further comprises a glue notch along its side; and

the mirror periods are bonded together by a bonding material deposited along the glue notches of the mirror periods.

14. The apparatus of claim 11, wherein:

the first semiconductor layer in each mirror period comprises a high resistivity silicon wafer;

the film layer in each mirror period comprises an oxide film; and

the second semiconductor layer in each mirror period comprises a silicon wafer.

15. The apparatus of claim 14, wherein:

the high resistivity silicon wafer in each mirror period is approximately 110 μ

m thick; and

the silicon wafer in each mirror period is approximately 125 μ

m thick.

16. The apparatus of claim 11, wherein the opening through the second semiconductor layer in each mirror period is 1.25 cm to 1.75 cm in width.

17. The apparatus of claim 11, further comprising:

a spacer layer formed under a bottom one of the stacked mirror periods.

18. The apparatus of claim 11, wherein the cavity in each mirror period comprises air.

19. A method comprising:

forming a semiconductor structure by fusion bonding a first wafer layer to an oxide film on a second wafer layer;

patterning an aperture in the second wafer layer;

dicing the semiconductor structure; and

stack bonding a plurality of the diced semiconductor structures to form a high reflectance mirror.

20. The method of claim 19, wherein the first wafer layer comprises a high resistivity silicon wafer.