Device with beam structure, and semiconductor device

• US 20070138608A1
• Filed: 05/23/2006
• Published: 06/21/2007
• Est. Priority Date: 12/20/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ikehashi, Tamio
• Granted Patent: US 7,485,958 B2
• Time in Patent Office: Days
• US Class Current: 257/669
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H10N 30/2041 Beam type
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end

Abstract

A device with a beam structure includes a substrate, an anchor and a cavity which are provided on and over the substrate, respectively, and a beam structure which is provided on the anchor and over the cavity, extends in a first direction and includes a plurality of convex portions and a plurality of concave portions, each of the convex portions having such a stress gradient as to provide a convex warp, and each of the concave portions having such a stress gradient as to provide a concave warp. The convex portions and the concave portions are alternately repeatedly arranged.

Claims

1. A device with a beam structure, comprising:

a substrate;

an anchor and a cavity which are provided on and over the substrate, respectively; and

a beam structure which is provided on the anchor and over the cavity, extends in a first direction and includes a plurality of convex portions and a plurality of concave portions, each of the convex portions having such a stress gradient as to provide a convex warp, and each of the concave portions having such a stress gradient as to provide a concave warp,

wherein the convex portions and the concave portions are alternately repeatedly arranged.

2. The device according to claim 1, wherein at least a part of the beam structure, where the convex portions and the concave portions are alternately repeatedly arranged, is substantially parallel to the substrate, with a ratio in length between the convex portions and the concave portions being fixed.

3. The device according to claim 1, wherein the beam structure includes a first layer, which has a first residual stress, and a plurality of adjustment layers, which are provided partly on the first layer and have a second residual stress which is different in sign from the first residual stress.

4. The device according to claim 3, wherein the first layer includes a plurality of layers having different residual stresses.

5. The device according to claim 3, wherein the second residual stress is relatively smaller than the first residual stress,

segments of the beam structure, where the adjustment layers are provided, correspond to the convex portions, and

segments of the beam structure, where the adjustment layers are not provided, correspond to the concave portions.

6. The device according to claim 3, wherein the second residual stress is relatively greater than the first residual stress,

segments of the beam structure, where the adjustment layers are provided, correspond to the concave portions, and

segments of the beam structure, where the adjustment layers are not provided, correspond to the convex portions.

7. The device according to claim 1, wherein a relational formula,

ρ

1/ρ

2=L1/L2,

is satisfied, where L1 is a total length of the concave portions, L2 is a total length of the convex portions, ρ

1 is a radius of curvature of the concave portions, and ρ

2 is a radius of curvature of the convex portions, and

a range of a tolerable error of a numerical value, which is calculated by the relational formula, is ±

40%.

8. The device according to claim 3, wherein the adjustment layers are provided such that when the beam structure is vertically cut in an arbitrary direction, a part of the adjustment layers is present in a cross section.

9. A device with a beam structure, comprising:

a substrate;

an anchor and a cavity which are provided on and over the substrate, respectively; and

a beam structure which is provided on the anchor and over the cavity, extends in a first direction and includes a base portion and a support portion,

wherein the support portion includes a first convex portion having such a stress gradient as to provide a convex warp, and a first concave portion having such a stress gradient as to provide a concave warp, the support portion adjusting a height of the base portion, which is different from a height of the anchor.

10. The device according to claim 9, wherein the base portion is substantially parallel to the substrate and includes a plurality of second convex portions and a plurality of second concave portions, each of the second convex portions having such a stress gradient as to provide a convex warp, and each of the second concave portions having such a stress gradient as to provide a concave warp, and

a length of one unit comprising the first convex portion and the first concave portion of the support portion is greater than a length of one unit comprising the second convex portion and the second concave portion of the base portion.

11. The device according to claim 9, wherein the support portion includes a first layer, which has a first residual stress, and an adjustment layer which is provided partly on the first layer and has a second residual stress that is different in sign from the first residual stress.

12. A semiconductor device comprising:

a substrate;

an anchor and a cavity which are provided on and over the substrate, respectively;

an actuator which is provided on the anchor and over the cavity and extends in a first direction; and

a plurality of first adjustment layers which are added partly to the actuator and adjust a warp of the actuator.

13. The semiconductor device according to claim 12, wherein the actuator has a first residual stress, and

the first adjustment layers have a second residual stress which is different in sign from the first residual stress.

14. The semiconductor device according to claim 12, wherein the actuator includes a lower electrode layer, a piezoelectric layer which is provided on the lower electrode layer, and an upper electrode layer which is provided on the piezoelectric layer.

15. The semiconductor device according to claim 12, wherein the first adjustment layers are insulating layers.

16. The semiconductor device according to claim 14, further comprising a first insulating layer which is provided on the upper electrode layer,

wherein the first adjustment layers are provided on the first insulating layer and are dummy wiring layers.

17. The semiconductor device according to claim 12, further comprising:

a first electrode layer which is provided on the substrate and beneath the cavity;

a second insulating layer which is provided on the first electrode layer; and

a second electrode layer which extends in the first direction from a distal end portion of the actuator, is provided above the first electrode layer, and is movable downward by the actuator,

wherein the first electrode layer, the second electrode layer and the second insulating layer function as a variable capacitor.

18. The semiconductor device according to claim 17, further comprising a plurality of second adjustment layers which are added partly to the second electrode layer and adjust a warp of the second electrode layer.

19. The semiconductor device according to claim 17, further comprising an inductor provided on the anchor and over the cavity, and including an inductor portion and support portion which adjusts a height of the inductor portion and supports the inductor portion,

wherein the support portion includes a convex portion having such a stress gradient as to provide a convex warp, and a concave portion having such a stress gradient as to provide a concave warp.

20. The semiconductor device according to claim 19, wherein the inductor includes a third insulating layer and a conductive layer provided on the third insulating layer, and

the support portion includes a third adjustment layer which is provided partly on the conductive layer, which corresponds to the support portion.