Exposure Method, Exposure Apparatus and Device Manufacturing Method

• US 20080218714A1
• Filed: 05/23/2006
• Published: 09/11/2008
• Est. Priority Date: 05/24/2005
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Omura, Yasuhiro, Nakano, Katsushi, Suzuki, Kousuke, Uehara, Yusaku
• Granted Patent: US 8,253,924 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70258 Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70558 Dose control, i.e. achievement of a desired dose

Abstract

An exposure apparatus is provided with an optical system including a liquid, a sensor system for acquiring energy information of an energy beam which is incident on the liquid, and a controller which predicts variation of optical properties of the optical system including the liquid due to energy absorption of the liquid based on the energy information acquired using the sensor system and controls exposure operation with respect to an object based on the prediction results. According to the exposure apparatus, exposure operation without being influenced by the variation of the optical properties of the optical system including the liquid due to the energy absorption of the liquid becomes possible.

Claims

1. An exposure method in which an energy beam is irradiated on an object via an optical system including a liquid and the object is exposed, the method comprising:

a process in which a variation of optical properties of the optical system due to energy absorption of the liquid is predicted, based on energy information of the energy beam which is incident on the liquid; and

a process in which exposure operation of the object is performed, based on a result of the prediction.

2. The exposure method according to claim 1 wherein

in the process to predict the variation of the optical properties of the optical system, the variation of the optical properties of the optical system due to the energy absorption of the liquid is predicted using a formula of computation which includes the energy information as a parameter.

3. The exposure method according to claim 2 wherein

the formula of computation includes a parameter related to temperature of the liquid.

4. The exposure method according to claim 2 wherein

the formula of computation includes a parameter related to transmittance of the liquid to the energy beam.

5. The exposure method according to claim 4 wherein

the parameter related to the transmittance of the liquid includes a parameter related to a variation of the transmittance of the liquid due to a change of dissolved oxygen concentration in the liquid.

6. The exposure method according to claim 4 wherein

an integrated exposure amount with respect to the object is controlled, based on the transmittance of the liquid.

7. The exposure method according to claim 2 wherein

measurement of an energy intensity of the energy beam which has passed through the optical system is performed at a predetermined timing, and

the formula of computation is updated based on a result of the measurement.

8. The exposure method according to claim 2 wherein

the optical system includes an optical element through which the energy beam passes, and

in the process to predict the variation of the optical properties of the optical system, the variation of the optical properties of the optical system due to the energy absorption of the optical element is also predicted using a formula of computation, which includes the energy information as a parameter, different from the formula of computation.

9. The exposure method according to claim 1 wherein

in the process to predict the variation of the optical properties of the optical system, the variation of the optical properties of the optical system is predicted, based on at least one of transmittance of the liquid to the energy beam and temperature of the liquid.

10. The exposure method according to claim 1 wherein

the optical system includes an optical element through which the energy beam passes, and

variation prediction of the optical properties of the optical system is performed taking into consideration energy absorption of the optical element.

11. The exposure method according to claim 1 wherein

the object is placed on a beam emitting side of an optical element that constitutes at least a part of the optical system, and

a beam path on the beam entering side of the optical element is filled with the liquid.

12. The exposure method according to claim 11 wherein

a space between the optical element and the object is filled with a dissimilar kind of liquid or the same kind but a different liquid.

13. The exposure method according to claim 12 wherein

in the process to predict the variation of the optical properties of the optical system, the variation of the optical properties of the optical system due to energy absorption of the different liquid is also predicted, using a formula of computation, which includes the energy information as a parameter, different from the formula of computation.

14. The exposure method according to claim 1 wherein

when the liquid on which the energy beam has been irradiated is replaced with the liquid on which the energy beam has not been irradiated,

it is regarded that there is no variation of the optical properties of the optical system due to the energy absorption of the liquid.

50. A device manufacturing method including a lithography process in which an object is exposed using the exposure method according to claim 1 to form a device pattern on the object.

15-49. -49. (canceled)

51. An exposure method in which an energy beam is irradiated on an object via a liquid and the object is exposed, wherein

the object is exposed while an integrated exposure amount to the object is controlled, based on a variation of physical quantities associated with transmittance of the liquid to the energy beam.

52. The exposure method according to claim 51 wherein

the physical quantities include the transmittance of the liquid to the energy beam.

53. The exposure method according to claim 51 wherein

the variation of the physical quantities of the liquid includes a change of dissolved oxygen concentration in the liquid.

54. The exposure method according to claim 53 wherein

measurement of the dissolved oxygen concentration in the liquid is performed, and

the integrated exposure amount to the object is controlled based on a result of the measurement.

55. The exposure method according to claim 51 wherein

the physical quantities include the dissolved oxygen concentration in the liquid.

56. The exposure method according to claim 55 wherein

measurement of the dissolved oxygen concentration in the liquid is performed, and

the integrated exposure amount to the object is controlled based on a result of the measurement.

57. A device manufacturing method including a lithography process in which an object is exposed using the exposure method according to claim 51 to form a device pattern on the object.

58. An exposure apparatus that irradiates an energy beam on an object via a liquid and exposes the object, the apparatus comprising:

an optical system that includes the liquid;

a sensor system that acquires energy information of the energy beam incident on the liquid; and

a control unit that performs prediction of a variation of the optical properties of the optical system including the liquid due to energy absorption of the liquid based on the energy information acquired using the sensor system, and controls exposure operation to the object, based on a result of the prediction.

59. The exposure apparatus according to claim 58 wherein

the control unit performs prediction of the variation of the optical properties of the optical system due to the energy absorption of the liquid, using a formula of computation which includes the energy information as a parameter.

60. The exposure apparatus according to claim 59 wherein

the formula of computation includes a parameter related to temperature of the liquid.

61. The exposure apparatus according to claim 59 wherein

the formula of computation includes a parameter related to transmittance of the liquid to the energy beam.

62. The exposure apparatus according to claim 61 wherein

the parameter related to transmittance of the liquid includes a parameter related to a variation of the transmittance of the liquid due to a change of dissolved oxygen concentration in the liquid.

63. The exposure apparatus according to claim 62, the apparatus further comprising:

an oximeter that measures dissolved oxygen concentration in the liquid.

64. The exposure apparatus according to claim 61 wherein

the control unit controls an integrated exposure amount to the object based on the transmittance of the liquid.

65. The exposure apparatus according to claim 59, the apparatus further comprising:

an illumination system that illuminates a predetermined pattern using the energy beam so as to project an image of the predetermined pattern on the object via the optical system, wherein

the controller unit sets the formula of computation for every illumination condition with respect to the predetermined pattern.

66. The exposure apparatus according to claim 59 wherein

the optical system includes an optical element through which the energy beam passes, and

the control unit also predicts the variation of the optical properties of the optical system due to the energy absorption of the optical element using a formula of computation, which includes the energy information as a parameter, different from the formula of computation.

67. The exposure apparatus according to claim 58 wherein

the control unit predicts the variation of the optical properties of the optical system, based on at least one of transmittance of the liquid to the energy beam and temperature of the liquid.

68. The exposure apparatus according to claim 58 wherein

the optical system includes an optical element through which the energy beam passes, and

the control unit performs prediction of variation of the optical properties of the optical system also taking into consideration the energy absorption of the optical element.

69. The exposure apparatus according to claim 58 wherein

the object is placed on a beam emitting side of an optical element that constitutes at least a part of the optical system, and

a beam path on the beam entering side of the optical element is filled with the liquid.

70. The exposure apparatus according to claim 69 wherein

a space between the optical element and the object is filled with a dissimilar kind of liquid or the same kind but a different liquid.

71. The exposure apparatus according to claim 70 wherein

the control unit also predicts the variation of the optical properties of the optical system due to the energy absorption of the different liquid using a formula of computation, which includes the energy information as a parameter, different from the formula of computation.

72. The exposure apparatus according to claim 58, the apparatus further comprising:

a liquid immersion system that can supply the liquid.

73. The exposure apparatus according to claim 72 wherein

the control unit replaces the liquid on which the energy beam has been irradiated with the liquid on which the energy beam has not been irradiated controlling the liquid immersion mechanism, and when the liquid immersion mechanism replaces the liquid, it is regarded that there is no variation of the optical properties of the optical system due to the energy absorption of the liquid.

74. The exposure apparatus according to claim 58, the apparatus further comprising:

a beam source that emits the energy beam, whereby

the sensor system has a branching unit which branches off a part of the energy beam between the beam source and the optical system and a sensor element on which an energy beam branched by the branching unit is incident.

75. A device manufacturing method including a lithography process in which an object is exposed using the exposure apparatus according to claim 58 to form a device pattern on the object.

76. An exposure apparatus that exposes an object by irradiating an energy beam on the object via a liquid, the apparatus comprising:

a beam source that emits the energy beam; and

a control unit that controls an integrated exposure amount to the object based on a variation of physical quantities associated with the transmittance of the liquid to an energy beam emitted from the beam source when the object is exposed.

77. The exposure apparatus according to claim 76 wherein

the physical quantities include the transmittance of the liquid to the energy beam.

78. The exposure apparatus according to claim 76 wherein

the variation of the physical quantities of the liquid includes a change of dissolved oxygen concentration in the liquid.

79. The exposure apparatus according to claim 78, the apparatus further comprising:

a measuring instrument that measures dissolved oxygen concentration in the liquid, whereby

the control unit controls an integrated exposure amount to the object based on measurement results of the measuring instrument.

80. The exposure apparatus according to claim 76 wherein

the physical quantities include the dissolved oxygen concentration in the liquid.

81. The exposure apparatus according to claim 80, the apparatus further comprising:

a measuring instrument that measures dissolved oxygen concentration in the liquid, whereby

the control unit controls an integrated exposure amount to the object based on measurement results of the measuring instrument.

82. A device manufacturing method including a lithography process in which an object is exposed using the exposure apparatus according to claim 76 to form a device pattern on the object.

83. A device manufacturing method including a lithography process in which an object is exposed by irradiating an energy beam on the object via an optical system including a liquid to form a device pattern on the object, the method comprising:

a process in which a variation of optical properties of the optical system due to energy absorption of the liquid is predicted, based on energy information of the energy beam which is incident on the liquid; and

a process in which exposure operation of the object is performed, based on a result of the prediction.

84. A device manufacturing method including a lithography process in which an object is exposed by irradiating an energy beam on the object via a liquid to form a device pattern on the object, the method comprising:

a process in which the energy beam is discharged from a beam source; and

a process in which the object is exposed while an integrated exposure amount to the object is controlled, based on a variation of physical quantities associated with transmittance of the liquid to the energy beam.

85. A device manufacturing method including a lithography process in which an object is exposed by irradiating an energy beam on the object via an optical system including a liquid to form a device pattern on the object, the method comprising:

a process in which energy information of the energy beam which is incident on the liquid is acquired, using a sensor system;

a process in which a variation of optical properties of the optical system including the liquid due to energy absorption of the liquid is predicted based on the energy information acquired using the sensor system; and

a process in which exposure operation of the object is performed, based on a result of the prediction.

86. A device manufacturing method including a lithography process in which an object is exposed by irradiating an energy beam on the object via an optical system including a liquid to form a device pattern on the object, the method comprising:

a process in which the energy beam is emitted from a beam source; and

a process in which the object is exposed by the energy beam from the beam source, while an integrated exposure amount to the object is controlled based on a variation of physical quantities associated with transmittance of the liquid to the energy beam emitted from the beam source.