IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0337510
(2003-01-07)
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발명자
/ 주소 |
- Pease, R. Fabian W.
- Ye, Jun
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출원인 / 주소 |
|
인용정보 |
피인용 횟수 :
53 인용 특허 :
44 |
초록
▼
A system to sense an aerial image produced by optical equipment used in, for example, semiconductor fabrication. In one embodiment, the system includes a photo-electron emission device which, in response to an aerial image projected thereon, emits electrons in a pattern corresponding to the light in
A system to sense an aerial image produced by optical equipment used in, for example, semiconductor fabrication. In one embodiment, the system includes a photo-electron emission device which, in response to an aerial image projected thereon, emits electrons in a pattern corresponding to the light intensity distribution produced by the aerial image. Electron optics provides an enlarged pattern of the pattern in which the electrons are emitted. A sensing unit senses the enlarged pattern. In another embodiment, the system employs a photo-conducting layer to project the aerial image thereon. The photo-conducting layer, in response to the projection of the aerial image thereon, produces local charge depletion corresponding to the light intensity distribution. A steering device delivers electrons to the photo-conducting layer to produce local re-charging currents in proportion to the local charge depletion. A pattern corresponding to the aerial image may be obtained from the re-charging currents.
대표청구항
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1. A system for sensing, at an increased resolution, an aerial image exhibiting a light intensity distribution at a primary resolution, the system comprising:a photo-electron emission unit to sense the aerial image and, in response, emit electrons in a pattern corresponding to the light intensity di
1. A system for sensing, at an increased resolution, an aerial image exhibiting a light intensity distribution at a primary resolution, the system comprising:a photo-electron emission unit to sense the aerial image and, in response, emit electrons in a pattern corresponding to the light intensity distribution of the aerial image; electron optics to project an enlarged pattern of the pattern of electrons emitted by the photo-electron emission unit; a sensing unit to sense the enlarged pattern; and an image analysis unit, coupled to the sensing unit, to digitize the enlarged pattern. 2. The system of claim 1 further comprising:an object; a light source to provide light; condensing optics to illuminate the object with the light; and an optical imaging and projection unit, wherein the optical imaging and projection unit projects the aerial image on the photo-electron emission unit. 3. The system of claim 2 wherein the photo-electron emission unit, electron optics and optical imaging and projection unit are disposed in or are a part of a photolithographic system.4. The system of claim 3 wherein the photolithographic system is a stepper or a scanner.5. The system of claim 4 wherein the object is a photolithographic mask.6. The system of claim 5 further includes a computer to inspect the photolithographic mask using the digitized aerial image.7. The system of claim 6 wherein the computer inspects the photolithographic mask using die-to-die inspection, die-to-database inspection, or image self-analysis techniques.8. The system of claim 4 further includes a controller, coupled to the image analysis unit, to adjust the operation of the photolithographic stepper or the photolithographic scanner using at least a portion of the digitized aerial image.9. The system of claim 4 wherein the light source provides a light that has a wavelength that is substantially equal to a wavelength of light that is used to expose a resist on a product wafer.10. The system of claim 4 further includes a mechanical positioning unit wherein, the mechanical positioning unit, in response to an operator input, positions the photo-electron emission unit at an image plane.11. The system of claim 4 further includes a mechanical positioning unit to position the photo-electron emission unit at an image plane to allow for in-situ aerial image sensing.12. The system of claim 4 wherein the light has a wavelength in the UV range.13. The system of claim 1 wherein the photo-electron emission unit includes an electron-multiplying cathode for amplifying the electrons.14. The system of claim 13 wherein the electron-multiplying cathode allows the emission of substantially thermalized electrons.15. The system of claim 1 wherein the photo-electron emission unit and the electron optics have a higher resolution than the resolution of the optical imaging and projection unit.16. A system for sensing an aerial image exhibiting a light intensity distribution at a primary resolution, the system comprising:a photo-conducting layer for projecting the aerial image thereon, wherein in response to the aerial image, the photo-conducting layer produces a depletion pattern corresponding to the light intensity distribution of the aerial image; an electron source for providing electrons; a steering device to direct the electrons to the photo-conducting layer to produce local re-charging currents in proportion to the local charge depletion; amplifier circuitry coupled to the steering device, wherein the amplifier circuitry determines a pattern corresponding to the serial image using the re-charging currents; and an image analysis unit, coupled to the sensing unit, to digitize the pattern. 17. The system of claim 16 further comprising:an object; a light source to provide light; condensing optics to illuminate the object with the light; and an optical imaging and projection unit to produce the aerial image on the photo-conducting layer. 18. The system of claim 17 wherein the photo-conducting layer, electron source, steering device and the optical imaging and projection unit are disposed in or are a part of a photolithographic system.19. The system of claim 18 wherein the photolithographic system is a photolithographic stepper or a photolithographic scanner.20. The system of claim 19 wherein the object is a photolithographic mask.21. The system of claim 20 further includes a computer to inspect the photolithographic mask using the digitized aerial image.22. The system of claim 21 wherein the computer inspects the photolithographic mask using die-to-die inspection, die-to-database inspection, or image self-analysis techniques.23. The system of claim 19 further includes a controller, coupled to the image analysis unit, to adjust the operation of the photolithographic stepper or a photolithographic scanner using at least a portion of the digitized aerial image.24. The system of claim 19 wherein the light source provides a light that has a wavelength that is substantially equal to a wavelength of light that is used to expose a resist on a product wafer.25. The system of claim 19 further includes a mechanical positioning unit wherein, the mechanical positioning unit, in response to an operator input, positions the photo-electron emission unit at the an image plane.26. The system of claim 19 further includes a mechanical positioning unit to position the photo-electron emission unit at the an image plane to allow for in-situ aerial image sensing.27. The system of claim 19 wherein the light has a wavelength in the UV range.
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