System and method for lithography process monitoring and control

• US 20060000964A1
• Filed: 08/25/2005
• Published: 01/05/2006
• Est. Priority Date: 03/18/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: Jun Ye, R. Fabian W. Pease, Xun Chen
• Inventors: Ye, Jun, Chen, Xun, Pease, R. Fabian W.
• Granted Patent: US 7,053,355 B2
• Time in Patent Office: Days
• US Class Current: 250/208.100
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/70591 Testing optical components
• CPC Class Codes: G03F 7/70666 Aerial image, i.e. measuring the image of the patterned exposure light at the image plane of the projection system
• CPC Class Codes: G03F 7/7085 Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

In one aspect, the present invention is a technique of, and a system and sensor for measuring, inspecting, characterizing and/or evaluating optical lithographic equipment, methods, and/or materials used therewith, for example, photomasks. In one embodiment, the system, sensor and technique measures, collects and/or detects an aerial image produced or generated by the interaction between the photomask and lithographic equipment. An image sensor unit may measure, collect, sense and/or detect the aerial image in situ—that is, the aerial image at the wafer plane produced, in part, by a product-type photomask (i.e., a wafer having integrated circuits formed during the integrated circuit fabrication process) and/or by associated lithographic equipment used, or to be used, to manufacture of integrated circuits. In this way, the aerial image used, generated or produced to measure, inspect, characterize and/or evaluate the photomask is the same aerial image used, generated or produced during wafer exposure in integrated circuit manufacturing. In another embodiment, the system, sensor and technique characterizes and/or evaluates the performance of the optical lithographic equipment, for example, the optical sub-system of such equipment. In this regard, in one embodiment, an image sensor unit measures, collects, senses and/or detects the aerial image produced or generated by the interaction between lithographic equipment and a photomask having a known, predetermined or fixed pattern (i.e., test mask). In this way, the system, sensor and technique collects, senses and/or detects the aerial image produced or generated by the test mask—lithographic equipment in order to inspect, evaluate and/or characterize the performance of the lithographic equipment.

Claims

1-40. -40. (canceled)

41. An image sensor unit, for use with photolithographic equipment, the image sensor unit comprising:

a substrate having a wafer or wafer-like shaped profile;

a sensor array, integrated into the wafer-shaped substrate, the sensor array including;

a plurality of sensor cells wherein each sensor cell includes an active area to sense light of a predetermined wavelength that is incident thereon; and

a film, disposed over the active areas of the plurality of sensor cells and comprised of a material that impedes passage of light of the predetermined wavelength, wherein the film includes a plurality of apertures which are arranged such that an aperture of the plurality of apertures overlies an active area of a corresponding sensor cell to expose a portion of the active area and wherein light of the predetermined wavelength is capable of being sensed by the portion of the active area that is exposed by the corresponding aperture.

42. The image sensor unit of claim 41 further including a transparent medium, having a predetermined refractive index, disposed on the sensor array.

43. The image sensor unit of claim 41 further including electrical contacts, disposed on or in the substrate, to provide a communication path with an external device.

44. The image sensor unit of claim 41 further including electrical contacts, disposed on or in the substrate, to receive electrical power from an external device.

45. The image sensor unit of claim 41 further including electrical contacts, disposed on or in the substrate, to output data to an external device.

46. The image sensor unit of claim 41 further including electrical contacts, disposed on or in the substrate, to input control signals from an external device.

47. The image sensor unit of claim 41 wherein the film is disposed between the active areas of the sensor cells and a protective outer layer of the sensor array.

48. The image sensor unit of claim 41 wherein the film is disposed on a protective outer layer of the sensor array.

49. The image sensor unit of claim 41 further including wireless communications circuitry, disposed on or in the substrate, to provide data to an external device.

50. The image sensor unit of claim 49 wherein the wireless communications circuitry provides data during collection of image data by the sensor array.

51. The image sensor unit of claim 41 wherein the sensor cells are charge coupled devices, CMOS devices or photodiodes.

52. The image sensor unit of claim 41 further including photon-conversion material, disposed:

(i) over the sensor array and between the film and the plurality of sensors, (ii) within the plurality of apertures of the film or (iii) on the sensor array.

53. The image sensor unit of claim 41 wherein the image sensor unit further includes data storage circuitry, coupled to the sensor array and integrated into the substrate, to store the data from the sensor array.

54. The image sensor unit of claim 41 further including a controller, integrated into or disposed on the substrate, to instruct the sensor array when to sample the intensity of light.

55. A system to collect image data which is representative of an aerial image of a mask that is projected, by an optical system, on a wafer plane of lithographic equipment, the system comprising:

an image sensor unit, disposed on the moveable platform, to collect data which is representative of the aerial image of the mask, the image sensor unit includes;

a substrate adapted to be disposed on a platform of the lithographic equipment;

a sensor array, disposed on or in, or integrated into the substrate, wherein the sensor array is capable of being located in the wafer plane, the sensor array includes;

a plurality of sensor cells wherein each sensor cell includes an active area to sense light of a predetermined wavelength that is incident thereon; and

a film, disposed over the active areas of the plurality of sensor cells and including a material that impedes passage of light of the predetermined wavelength, wherein the film includes a plurality of apertures which are arranged such that an aperture of the plurality of apertures overlies an associated active area of a corresponding sensor cell to expose a portion of the associated active area and wherein light of the predetermined wavelength is capable of being sensed by the portion of the active area that is exposed by the associated aperture.

56. The system of claim 55 further including a controller, disposed in the lithographic equipment and coupled to the image sensor unit, to control the operation of the image sensor unit.

57. The system of claim 55 further including a controller, coupled to the image sensor unit and disposed externally to the lithographic equipment, to control the operation of the image sensor unit.

58. The system of claim 55 wherein the image sensor unit further includes a controller, coupled to the sensor array and integrated into or disposed on the substrate, to control the operation of the image sensor unit.

59. The system of claim 55 wherein the image sensor unit further includes electrical contacts, disposed on or in the substrate, to provide a communication path with the lithographic equipment.

60. The system of claim 55 wherein the image sensor unit further includes electrical contacts, disposed on or in the substrate, to receive electrical power from lithographic equipment.

61. The system of claim 55 wherein the film of the image sensor unit is disposed between the active areas of the sensor cells and a protective outer layer of the sensor array.

62. The system of claim 55 wherein the film of the image sensor unit is disposed on a protective outer layer of the sensor array.

63. The system of claim 55 wherein the image sensor unit further includes wireless communications circuitry, disposed on or in the substrate, to provide data to the lithographic device during or after collection of image data by the sensor array.

64. The system of claim 55 wherein the image sensor unit further includes wireless communications circuitry, disposed on or in the substrate, to provide data to the processor/controller during or after collection of image data by the sensor array.

65. The system of claim 55 wherein the sensor cells of the image sensor unit are charge coupled devices, CMOS devices or photodiodes.

66. The system of claim 55 wherein the image sensor unit further includes data storage circuitry, coupled to the sensor array and disposed on or integrated into the substrate of the sensor array unit, to store the data from the sensor array.

67. The system of claim 55 wherein the image sensor unit further includes a controller, integrated into or disposed on the substrate, to control the operation of the sensor array.

68. An image sensor unit, for use with photolithographic equipment, the image sensor unit comprising:

a substrate adapted to be disposed on a platform of the lithographic equipment;

a sensor array, disposed on or in, or integrated into the substrate, the sensor array including;

a plurality of sensor cells wherein each sensor cell includes an active area to sense light of a predetermined wavelength that is incident thereon; and

a film, disposed over the active areas of the plurality of sensor cells and comprised of a material that impedes passage of light of the predetermined wavelength, wherein the film includes a plurality of apertures which are arranged such that an aperture of the plurality of apertures overlies an active area of a corresponding sensor cell to expose a portion of the active area and wherein light of the predetermined wavelength is capable of being sensed by the portion of the active area that is exposed by the corresponding aperture.

69. The image sensor unit of claim 68 further including electrical contacts, disposed on or in the substrate, to receive electrical power from an external device.

70. The image sensor unit of claim 68 further including electrical contacts, disposed on or in the substrate, to provide a communication path with an external device.

71. The image sensor unit of claim 68 wherein the film is disposed between the active areas of the sensor cells and a protective outer layer of the sensor array.

72. The image sensor unit of claim 68 wherein the film is disposed on a protective outer layer of the sensor array.

73. The image sensor unit of claim 68 wherein the sensor cells are charge coupled devices, CMOS devices or photodiodes.

74. The image sensor unit of claim 68 wherein the image sensor unit further includes:

a controller, integrated into or disposed on the substrate, to instruct the sensor array when to sample the intensity of light; and

data storage circuitry, coupled to the sensor array and integrated into or disposed on the substrate, to store the data which is representative of the intensity of light sampled by the sensor array.