Incident light angle detector for light sensitive integrated circuit
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
C23C-016/52
C23C-014/22
C23C-016/44
H01L-031/062
H01L-031/06
H01L-021/66
출원번호
US-0471054
(2006-06-19)
등록번호
US-7466002
(2008-12-16)
발명자
/ 주소
Shaffer,Jamie Lyn
출원인 / 주소
Mitutoyo Corporation
대리인 / 주소
Christensen O'Connor Johnson Kindness PLLC
인용정보
피인용 횟수 :
2인용 특허 :
8
초록▼
A detector configuration determines the direction of illumination incident on a photosensitive device. Multiple mask layers include holes which form an interlayer optical path through which radiation reaches a photodetector. The interlayer optical path provides a selected nominal maximum signal angl
A detector configuration determines the direction of illumination incident on a photosensitive device. Multiple mask layers include holes which form an interlayer optical path through which radiation reaches a photodetector. The interlayer optical path provides a selected nominal maximum signal angle and the detector senses when radiation is received at or near that angle. In one embodiment, three holes in three metallization layers provide an arbitrarily narrow interlayer optical path with improved angular detection relative to that provided by two holes. An illumination direction-sensing array may use multiple instances of the detector configuration. The detector configuration may provide enhanced utility and economy by being adapted to use only those fabrication steps used for fabricating other primary circuits on an IC.
대표청구항▼
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A photosensitive device including at least a first illumination direction sensing detector configuration that is used to provide an illumination direction indicating signal that varies
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A photosensitive device including at least a first illumination direction sensing detector configuration that is used to provide an illumination direction indicating signal that varies as a function of an illumination direction relative to the device of incident radiation falling on the device, the illumination direction sensing detector configuration comprising: a first photodetector on a photodetector substrate, the first photodetector being operable to output a first signal that varies depending on an amount of radiation it receives; a first mask layer fixed proximate to a surface of the first photodetector, the first mask layer including a first-layer hole arranged to receive radiation along an interlayer optical path and transmit radiation to the first photodetector; and a second mask layer fixed proximate to a surface of the first mask layer, the second mask layer including a second-layer hole arranged to receive the incident radiation along its illumination direction relative to the device and transmit the incident radiation to the first-layer hole along the interlayer optical path; wherein: the second-layer hole that transmits the incident radiation to the first-layer hole along the interlayer optical path defines an input of the interlayer optical path, the second-layer hole having an input area; the first-layer hole that receives radiation along the interlayer optical path and transmits the radiation to the first photodetector defines an output of the interlayer optical path, the first-layer hole having an output area; the first photodctector is configured to have dimensions arranged relative to the interlayer optical path such that any incident radiation light rays that are at the most extreme angles that may pass through both the first layer hole and the second layer hole and along the interlayer optical path fall within the active area of the first photodetector; and the interlayer optical path is configured to define a nominal peak signal direction and is also configured such that, for a first range of illumination directions that includes the nominal peak signal direction, the amount of radiation received by the first photodetector through the interlayer optical path is a maximum when the illumination direction approximately coincides with the nominal peak signal direction and the amount of radiation received by the first photodetector through the interlayer optical path decreases as a function of increasing deviation between the illumination direction and the nominal peak signal direction throughout the first range, such that the first signal output by the first photodetector varies throughout the first range as a function of the illumination direction of the incident radiation falling on the device. 2. The device of claim 1, wherein a third mask layer fixed between the first and second mask layers includes a third-layer hole arranged in an offset manner relative to the first-and second-layer holes such that a cross-section through the resulting interlayer optical path along a plane approximately parallel to a plane of the first mask layer and a plane of the second mask layer has a smaller area than the input area of the second-layer hole and the output area of the first-layer hole and is utilized for providing a higher angular resolution for the sensing of the illumination direction relative to an angular resolution that would be available from utilizing the first and second-layer holes alone. 3. The device of claim 2, wherein the cross-section through the resulting interlayer optical path has a smaller area than the area of the minimum hole size specified for the fabrication processes used to fabricate the device. 4. The device of claim 1, wherein the photosensitive device includes circuit elements that are not used for sensing the illumination direction and at least some of which are fabricated in at least one of the first mask layer and the second mask layer. 5. The device of claim 4, wherein the circuit elements that are not used for sensing the illumination direction include a photodetector array that does not include the first photodetector, and the first photodetector is formed during the same process steps that are used to form the photodetectors of the photodetector array that does not include the first photodetector and without the use of additional process steps. 6. The device of claim 4, wherein at least one material layer is formed between the first mask layer and the second mask layer, the at least one material layer comprising at least one optically transmissive insulating layer, and each material layer formed between the first and second mask layers is used to fabricate one of a circuit element, an insulator for a circuit element, and a protective layer for a circuit element, for a circuit element that is not used for sensing the illumination direction. 7. The device of claim 1, wherein: the first range of illumination directions that includes the nominal peak signal direction is a two-dimensional range comprising an angle of incidence range and an azimuthal angle range; the photosensitive device includes a plurality of respective illumination direction sensing detector configurations similar to the first illumination direction sensing detector configuration for sensing an illumination direction of the incident radiation, each respective illumination direction sensing configuration having a respective first photodetector and a respective interlayer optical path that is configured to define a respective nominal peak signal direction and that is also configured such that, for a respective first range of illumination directions that includes the respective nominal peak signal direction, amount of radiation received by the respective first photodetector through the respective interlayer optical path is a maximum when the illumination direction approximately coincides with the respective nominal peak signal direction and the amount of radiation received b the respective first photodetector through the respective interlayer optical path decreases as a function of increasing deviation between the illumination direction and the respective nominal peak signal direction throughout the respective first range, such that a respective first signal output by the respective first photodetector varies throughout the respective first range as a function of the illumination direction of the incident radiation falling on the device; and a combination of the respective first signal outputs is indicative of an angle of incidence component and an azimuthal angle component of the direction of illumination. 8. The device of claim 7, wherein the device includes a circuit which processes a combination of the respective first signal outputs and indicates when the direction of illumination approximately coincides with a predetermined direction of illumination. 9. The device of claim 1, further comprising a wavelength selective filter that filters the radiation reaching the first photodetector. 10. The device of claim1, wherein: the second mask layer includes two respective second-layer holes, the two respective second-layer holes providing inputs for the first interlayer optical path and a second interlayer optical path, each interlayer optical path formed in combination with the first-layer hole; the first photodetector is configured to have dimensions arranged relative to the second interlayer optical path such that any incident radiation light rays that are at the most extreme angles that may pass through both the first layer hole and the respective second layer hole of the second interlayer optical path fall within the active area of the first photodetector; each of the first and second interlayer optical paths transmit radiation to the first photodetector; the first interlayer optical path defines a first nominal peak signal direction comprising a first angle of incidence component and a first azimuthal angle component and the second interlayer optical path defines a second nominal peak signal direction comprising a second angle of incidence component and a second azimuthal angle component; the first interlayer optical path is configured such that, for a first range of illumination directions that includes the first nominal peak signal direction, the amount of radiation received by the first photodetector is a maximum when the illumination direction approximately coincides with the first nominal peak signal direction and the amount of radiation received by the first photodetector through the first interlayer optical path decreases as a function of increasing deviation between the illumination direction, and the first nominal peak signal direction throughout the first range when the illumination direction is within the first range of illumination directions; and the second interlayer optical path is configured such that, for a second range of illumination directions that includes the second nominal peak signal direction, the amount of radiation received by the first photodetector is a maximum when time illumination direction approximately coincides with the second nominal peak signal direction, and the amount of radiation received by the first photodetector through the second interlayer optical path decreases as a function of increasing deviation between the illumination direction and the second nominal peak signal direction throughout the second range when the illumination direction is within the second range of illumination directions, such that the first signal output by the first photodetector varies throughout the first and second ranges as a function of the illumination direction of the incident radiation falling on the device. 11. The device of claim 1, wherein: the photosensitive device includes a second illumination direction sensing detector configuration similar to the first illumination direction sensing detector configuration for sensing an illumination direction of the incident radiation; each of the two illumination direction sensing detector configurations have different respective interlayer optical paths, different respective nominal peak signal directions and different respective photodetectors; and the two illumination direction sensing detector configurations use the same second-layer hole as the input to their respective interlayer optical paths. 12. The device of claim 1, wherein: the first mask layer includes a plurality of respective first-layer holes that transmit radiation to the first photodetector; the second mask layer includes a plurality of respective second-layer holes, each respective second layer hole transmitting the incident radiation to a respective one of the first-layer holes along a respective interlayer optical path; each respective interlayer optical path has a nominal peak signal direction and at least two respective interlayer optical paths are configured to have parallel nominal peak signal directions; and the first photodetector is arranged relative to the at least two respective interlayer optical paths such that for a first range of illumination directions that includes the parallel nominal peak signal directions the amount of radiation received by the first photodetector is a maximum when the illumination direction approximately coincides with the parallel nominal peak signal directions, and the amount of radiation received by the first photodetector decreases as a function of increasing deviation between the illumination direction and the parallel nominal peak signal directions when the illumination direction is within the first range of illumination directions. 13. A method of fabricating at least a first instance of an illumination direction sensing detector configuration on a photosensitive device, the method comprising: fabricating the illumination direction sensing detector configuration such that it provides a signal that varies as a function of an illumination direction relative to the device of incident radiation falling on the device, the fabricating of the illumination direction sensing detector configuration comprising: fabricating a first photodetector on a photodetector substrate, the first photodetector being operable to output a first signal that varies depending on an amount of radiation it receives; fabricating a first mask layer fixed proximate to a surface of the first photodetector, the first mask layer being processed to include a first-layer hole that is arranged to receive radiation along an interlayer optical path and transmit radiation to the first photodetector; and fabricating a second mask layer fixed proximate to a surface of the first mask layer, the second mask layer being processed to include a second-layer hole that is arranged to receive the incident radiation along its illumination direction relative to the device and transmit the incident radiation to the first-layer hole along the interlayer optical path; wherein: the second-layer hole that transmits the incident radiation to the first-layer hole along the interlayer optical path defines an input of the interlayer optical path, the second-layer hole having an input area; the first-layer hole that receives radiation along the interlayer optical path and transmits the radiation to the first photodetector defines an output of the interlayer optical path, the first layer hole having an output area; fabricating the first photodetector comprises configuring the first photodetector to have dimensions arranged relative to the interlayer optical path such that any incident radiation light rays that are at the most extreme angles that may pass through both the first layer hole and the second layer hole and along the interlayer optical path fall within the active area of the first photodetector; and fabricating the illumination direction sensing detector further comprises configuring the interlayer optical path to define a nominal peak signal direction, and configuring the interlayer optical path such that, for a first range of illumination directions that includes the nominal peak signal direction, the amount of radiation received by the first photodetector through the interlayer optical path is a maximum when the illumination direction approximately coincides with the nominal peak signal direction and the amount of radiation received by the first photodetector through the interlayer optical path decreases as a function of increasing deviation between the illumination direction and the nominal peak signal direction throughout the first range, such that the first signal output by the first photodetector varies throughout the first range as a function of the illumination direction of the incident radiation falling on the device. 14. The method of claim 13, further comprising fabricating a third mask layer fixed between the first and second mask layers, the third mask layer being processed to include a third-layer hole arranged in an offset manner relative to the first-and second-layer holes such that a cross-section through the resulting interlayer optical path along a plane approximately parallel to a plane of the first mask layer and a plane of the second mask layer has a smaller area than the input area of the second-layer hole and the output area of the first-layer hole and utilizing the resulting interlayer optical path for providing a higher angular resolution for the sensing of the illumination direction relative to an angular resolution that would be available from utilizing the first and second-layer holes alone. 15. The method of claim 14, wherein the cross-section through the resulting interlayer optical path has a smaller area than the area of the minimum hole size specified for the fabrication processes used to fabricate the device. 16. The method of claim 13, further comprising fabricating additional circuit elements that are riot used for sensing the illumination direction, the additional circuit elements being fabricated in at least one of the first mask layer and the second mask layer. 17. The method of claim 16, wherein the circuit elements that are not used for sensing the illumination (direction include a photodetector array that does not include the first photodetector, and the first photodetector is formed during the same process steps that are used to form the photodetectors of the photodetector array that does not include the first photodetector and without the use of additional process steps. 18. The method of claim 16, further comprising forming the first mask layer and the second mask layer from metal layers that are used to fabricate circuit connections on the photosensitive device. 19. The method of claim 16, further comprising forming at least one material layer between the first mask layer and the second mask layer, the at least one material layer comprising at least one optically transmissmive insulating layer, and each material layer formed between the first and second mask layers is used to fabricate one of a circuit element, an insulator for a circuit element, and a protective layer for a circuit element, for a circuit element that is not used for sensing the illumination direction. 20. The device of claim 5, wherein the photodetector array that does not include the first photodetector comprises a quadrature detector array usable in an optical encoder system for determining physical measurements. 21. A method for operating the device of claim 20, comprising: providing an optical encoder system comprising the device of claim 20, a light source and a scale; operably arranging the optical encoder system such that light from the light source is reflected from a surface of the scale to the device of claim 20, wherein the light reflected from the surface of the scale to the device of claim 20 provides an incident radiation having an illumination direction relative to the device of claim 20; sensing the illumination direction using the device of claim 20; and adjusting the alignment of components of the operably arranged optical encoder system based at least partially on an output signal of the device of claim 20 and providing a desired orientation of the light source relative to the surface of the scale. 22. The device of claim 4, wherein the first mask layer and the second mask layer are formed from metal layers that are used to fabricate circuit connections on the photosensitive device. 23. The device of claim 6, wherein the interlayer optical path is filled with optically transmissive insulating material.
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이 특허에 인용된 특허 (8)
Hill Jerry M. (Brentwood TN 4), Apparatus and method for angle measurement.
Dunavan David S. (Norwalk CT) Abreu Rene (New Fairfield CT) Messelt Stephen (Roxbury CT) Siebert Edward (New Fairfield CT), Optical direction sensor having gray code mask spaced from a plurality of interdigitated detectors.
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