System and method for providing residual stress test structures
First Claim
1. A test unit configured to indicate residual stress in a deposited film, wherein the test unit is configured to interferometrically modulate light indicative of average residual stress in two orthogonal directions of the film.
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Accused Products
Abstract
The invention comprises systems and methods determining residual stress such as that found in interferometric modulators. In one example, a test unit can be configured to indicate residual stress in a film by interferometrically modulating light indicative of an average residual stress in two orthogonal directions of the substrate. The test unit can include a reflective membrane attached to the substrate where membrane is configured as a parallelogram with at least a portion of each side attached to the substrate, and an interferometric cavity formed between a portion of the membrane and a portion of the substrate, and where the membrane is configured to deform based on the residual stress of in the film and modulate light indicative of the amount of membrane deformation.
113 Citations
64 Claims
- 1. A test unit configured to indicate residual stress in a deposited film, wherein the test unit is configured to interferometrically modulate light indicative of average residual stress in two orthogonal directions of the film.
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6. A system configured to determine residual stress of a deposited film, comprising:
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one or more test units, each test unit comprising a reflective membrane that comprises a portion of the deposited film, wherein the membrane is configured as a parallelogram with at least a portion of each side attached to a substrate, wherein the membrane is configured to deform based on the residual stress of the film and modulate light indicative of the amount of membrane deformation; an imaging system positionable to receive modulated light reflecting from the one or more test units and configured to produce image data associated with the received light; and a computer in communication with the imaging system, the computer configured to process the image data and generate information relating to the residual stress in the film. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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- 14. A method of measuring residual stress of a deposited film, the method comprising interferometrically modulating light using a membrane that deforms based on residual stress of the film such that the modulated light indicates the residual stress in the film in two orthogonal directions.
- 20. A test unit for measuring residual stress in a deposited film, comprising means for reflecting a first portion of light, and means for reflecting a second portion of light that interferes with the first portion of light to modulate light indicative of average residual stress in two orthogonal directions of the film.
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27. A method of manufacturing a device to indicate the residual stress in a deposited film, the method comprising disposing a thin reflective membrane on a substrate such that an interferometric cavity is formed between a portion of the membrane and a portion of the substrate, wherein the membrane comprises a portion of the deposited film, and wherein the membrane is configured in the shape of a parallelogram with at least a portion of each side attached to the substrate, and the membrane is further configured to deform based on the residual stress of the film in two orthogonal directions and modulate light indicative of the amount of deformation.
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28. A system for measuring residual stress in a deposited film, comprising:
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a test unit comprising a reflective membrane attached to the substrate, the test unit configured to modulate light using an interferometric cavity formed between the membrane and the substrate and wherein the membrane comprises a portion of the deposited film; an electrode disposed such that at least a portion of the interferometric cavity is between the electrode and the membrane; and a power source configured to apply a voltage between the membrane and the electrode, wherein the test unit is configured such that the membrane moves at a frequency in response to the applied voltage, and wherein the modulated light is indicative of when the beam is moving at a resonant frequency, the resonant frequency being based on the residual stress of the deposited film. - View Dependent Claims (29, 30)
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31. A method of measuring residual stress in a deposited film, comprising:
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moving a membrane attached to the substrate at a resonant frequency wherein the membrane comprises a portion of the deposited film; modulating light interferometrically based on the movement of the membrane; detecting the modulated light; and determining the residual stress in the deposited film based on the detected modulated light. - View Dependent Claims (32, 33, 34, 35, 36)
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37. A system for measuring residual stress in a deposited film, comprising:
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means for moving a membrane attached to the substrate at a resonant frequency; means for modulating light interferometrically based on the movement of the membrane; means for detecting the modulated light; and means for determining the residual stress in the film based on the detected modulated light. - View Dependent Claims (38, 39, 40, 41, 42, 43)
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44. A method of manufacturing a test unit to indicate the residual stress in a film, the method comprising:
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disposing a reflective membrane on a substrate such that an interferometric cavity is formed between a portion of the membrane and a portion of the substrate, wherein the membrane is connected to the substrate on two opposite and parallel sides, wherein the membrane comprises a portion of the film, and wherein the membrane configured to deform based on the residual stress of the film and modulate light indicative of the amount of deformation; disposing an electrode such that the interferometric cavity is between the membrane and the electrode; and connecting a voltage source to the membrane and the electrode, the voltage source configured to provide voltage across the membrane and electrode such that the membrane moves at a resonant frequency.
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45. A display device, comprising:
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a substrate; one or more one bi-stable display elements disposed on the substrate wherein each the one or more bi-stable display elements comprise a moveable membrane which comprises a portion of a film; and one or more test units, each test unit comprising a membrane defining a portion of an interferometric cavity, wherein the membrane comprises a portion of the film, wherein the one or more test units are configured to modulate light such that the modulated light is indicative of the residual stress of the film. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53)
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54. A method of determining residual stress of a film layer incorporated in a display, comprising:
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interferometrically modulating light, wherein the modulated light is indicative of the residual stress in the film layer; detecting the modulated light; generating image data associated with the detected modulated light; and determining residual stress of the film layer of the display based on the image data. - View Dependent Claims (55, 56)
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57. A system for determining residual stress in film incorporated in a display, comprising:
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means for interferometrically modulating light at one or more test units disposed near a display, wherein the modulated light is indicative of the residual stress in the film; means for detecting the modulated light; means for generating image data associated with the detected modulated light; and means for determining residual stress in the film based on the image data. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64)
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Specification