Article comprising a MEMS device and method therefor

• US 6,771,850 B1
• Filed: 11/18/2000
• Issued: 08/03/2004
• Est. Priority Date: 11/18/2000
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.), Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Greywall, Dennis S.
• Primary Examiner(s): Bruce, David V.
• Assistant Examiner(s): KAO, CHIH CHENG G
• Application Number:
  US09/715,575
• Time in Patent Office: 1,354 Days
• Field of Search: 385/15-19, 385/23-25, 385/47, 359/223, 359/225, 359/226, 359/230, 359/872, 359/876, 359/877, 359/224, 359/298, 359/871, 257/98, 257/700, 438/26, 438/27, 438/29, 438/31, 438/64, 438/65, 438/66
• US Class Current: 385/17
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/353 the optical element being a shutter, baffle, beam dump or opaque element absorbers on light guide termination G02B6/243
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3566 involving bending a beam, e.g. with cantilever
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C

Abstract

An article comprising a support portion that is coupled to an element portion, both of which portions are formed from some of the layers of a multi-layer substrate. In one embodiment, the support portion comprises a torsional member, an actuating plate and a beam, wherein the beam mechanically links the actuating plate and the element portion. At least one torsional member attaches the support portion to the multi-layer substrate and allows the element portion to move independently of the substrate, such as when actuated by an underlying electrode. When actuated, the actuating plate of the support portion is drawn toward the underlying electrode while the element portion rises from a first (unactuated) position within the substrate toward a second (actuated) position outside of the substrate, in see-saw like fashion. The present article is useful in a variety of applications, such as, for example, optical applications where it can be used to form improved chopper switches and optical cross connects.

Claims

1. An article comprising:

a multi-layer substrate having a first and second layer and each having a thickness;

a support portion defined from said first layer and having a length and an actuating end, and said support portion rotatably coupled to, said multi-layer substrate;

an optical element portion coupled to and depending from an end of said support portion opposite said actuating end, said optical element having a length less than said length of said support portion and having a thickness substantially defined by said thickness of said second layer, said element portion is movable between;

a first position within said multi-layer substrate below an exterior surface thereof, and

a second position outside of said multi-layer substrate above said exterior surface thereof.

2. The article of claim 1 wherein said multi-layer substrate comprises an intermediate layer separating said first layer and said second layer.

3. The article of claim 1 wherein said support portion comprises a torsional member that is rotatably coupled to said first layer.

4. The article of claim 3 wherein said support portion further comprises a beam, wherein said optical element portion depends from said beam.

5. The article of claim 4 wherein a working surface of said optical element portion is physically adapted to receive an optical signal.

6. The article of claim 5 wherein said physical adaptation of said working surface is reflective, and further wherein said working surface is substantially orthogonal to said exterior surface of said multi-layer substrate.

7. The article of claim 6 wherein:

said torsional member and said beam comprise a part of said first layer; and

said optical element portion comprises a part of said second layer.

8. The article of claim 7 wherein a height of said working surface of said optical element portion is defined by a thickness of said second layer.

9. The article of claim 8 wherein said first layer and said second layer comprise silicon.

10. The article of claim 1 wherein said multi-layer substrate comprises a silicon-on-insulator wafer having a thin silicon layer overlying an insulating layer that overlies a thick silicon layer, and further wherein said thin silicon layer is said first layer;

said insulating layer is an intermediate layer; and

said thick silicon layer is said second layer.

11. The article of claim 1

wherein said actuating end is an actuating plate;

and

said article further includes an electrode disposed in spaced relation with said actuating plate, wherein;

under an action of an applied potential difference, said electrode is operable to cause said actuating plate to move into said multi-layer substrate, which movement in turn causes said optical element portion to move towards said second position.

12. The article of claim 11 further comprising a first waveguide and a second waveguide that are disposed in orthogonal relation to one another, wherein:

when said optical element portion is in said first position, said first waveguide and said second waveguide are in optical communication with one another; and

when said optical element portion is in said second position, said first waveguide and said second waveguide are not in optical communication with one another.

13. The article of claim 12 wherein said article is an optical cross connect.

14. An article comprising a support portion that is defined from at least an outer first layer of a multi-layer substrate, said support portion having a length and an actuating end and an optical element portion coupled to and depending from said support portion and having a length less than a length of said support portion and being located at an end opposite said actuating end, said optical element further having a thickness that is substantially defined by a thickness of an inner second layer of said multi-layer substrate, wherein an interior of said multi-layer substrate is defined between a top surface of said first layer and a bottom surface of said second layer, and said optical element portion comprises a part of said second layer, wherein at least a portion of said optical element portion is movable between a first position in said interior of said multi-layer substrate and a second position above said top surface of said first layer.

15. The article of claim 14 wherein a working surface of said optical element portion is physically adapted to receive an optical signal, and further wherein said working surface is disposed in orthogonal relation to said top surface of said first layer.

16. The article of claim 15, wherein a height of said working surface is defined by a thickness of said second layer of said multi-layer substrate.

17. An article comprising:

an array having n columns and n rows of optical elements that are disposed in and rotatably coupled to a first layer of a multi-layer substrate;

a first 1×

n array of optical waveguides, wherein each of said optical waveguides in said first array is aligned for optical communication with said optical elements in one of said n columns; and

a second 1×

n array of optical waveguides disposed in orthogonal relation to said first array of optical waveguides, wherein each of said optical waveguides in said second array is aligned for optical communication with said optical elements in one of said n rows;

wherein, each optical element comprises;

an element portion that is defined from at least a second layer of said multi-layer substrate, said second layer having a thickness and said element portion having a thickness substantially defined by said thickness of said second layer, said element portion having an optical signal receiving surface that is disposed in orthogonal relation to a major surface of said multi-layer substrate;

a support portion having a length and defined from said first layer and rotatable coupled to said multi-layer substrate and having an actuating end, and said element portion having a length less than said length of said support portion and being coupled to and depending from said support portion at an end opposite to said actuating end, wherein said support portion allows said element portion to move independently of said multi-layer substrate; and

an electrode operable, under an action of an applied potential difference, to cause said element portion to move to between;

a first position wherein said element portion is within said multi-layer substrate; and

a second position wherein at least a portion of said element portion is above an exterior surface of said multi-layer substrate.

18. The article of claim 17 further comprising collimating/focusing lenses that are operable to collimate optical signals leaving said optical waveguides of said first and second arrays and to focus optical signals entering said optical waveguides.

19. The article of claim 17 wherein said multi-layer substrate comprises a silicon-on-insulator wafer having a thick silicon layer, a layer of oxide disposed on said thick silicon layer, and a thin silicon layer disposed on said layer of oxide.

20. The article of claim 19 wherein said element portion comprises a part of said thick silicon layer.

21. The article of claim 20 wherein said optical signal receiving surface of said element portion comprises facets having a <

111>

crystal orientation.