JP2002324752A5

JP2002324752A5 -

Info

Publication number: JP2002324752A5
Application number: JP2002023547A
Authority: JP
Filing date: 2002-01-31
Publication date: 2005-09-15
Anticipated expiration: 2022-01-31

Claims

A method of manufacturing a projection optical system used in an optical device,
A first step of obtaining target information to be achieved by the optical device;
A second step of determining a specification of the projection optical system based on the target information, using a wavefront aberration that the projection optical system should satisfy as a standard value;
And a third step of adjusting the projection optical system so as to satisfy the specifications.

In the second step, the wavefront of the projection optical system is expanded by a Zernike polynomial, and among the coefficients of each term of the polynomial, the coefficient of a specific term selected based on the target information is used as a standard value for the projection optical system. The method of manufacturing a projection optical system according to claim 1, wherein:

In the second step, the RMS value of the coefficient of each term of the Zernike polynomial that develops the wavefront of the projection optical system is used as a standard value, and the RMS value in the entire field of view of the projection optical system does not exceed a predetermined allowable value. The method of manufacturing a projection optical system according to claim 1, wherein specifications of the projection optical system are determined as described above.

In the second step, the value of the coefficient of each term of the Zernike polynomial that develops the wavefront of the projection optical system is set as a standard value, and the projection optical system is set so that the coefficient does not exceed each individually determined allowable value. The method of manufacturing a projection optical system according to claim 1, wherein:

In the second step, among the coefficients of the terms of the Zernike polynomial that develops the wavefront of the projection optical system, the RMS value within the field of the projection optical system of the coefficient of the n-th order mθ term corresponding to the particular aberration of interest The projection optical system manufacturing method according to claim 1, wherein a specification value of the projection optical system is determined so that the RMS value does not exceed a predetermined allowable value.

In the second step, among the coefficients of the terms of the Zernike polynomial that develops the wavefront of the projection optical system, the terms corresponding to the specific aberration of interest are separated into a plurality of groups for each mθ term, The specification of the projection optical system is set so that the RMS value of the coefficient of each term included in the field of view of the projection optical system is a standard value, and the RMS value of each group does not exceed individually determined tolerances. The method of manufacturing a projection optical system according to claim 1, wherein the projection optical system is determined.

In the second step, the RMS value of the coefficient of each term after weighting the coefficient of each term of the Zernike polynomial that develops the wavefront of the projection optical system according to the target information is used as a standard value, and The projection optical system manufacturing method according to claim 1, wherein the specification of the projection optical system is determined so that an RMS value of a coefficient of each term of the plurality of terms does not exceed a predetermined allowable value.

The third step includes a step of measuring the wavefront aberration of the projection optical system, and a step of adjusting the projection optical system based on the measurement result of the wavefront aberration so that the projection optical system satisfies the specifications; The method for manufacturing a projection optical system according to claim 1, comprising:

9. The method of manufacturing a projection optical system according to claim 8, wherein the measurement of the wavefront aberration is performed before the projection optical system is incorporated into a main body of the optical device.

The method of manufacturing a projection optical system according to claim 8, wherein the measurement of the wavefront aberration is performed after the projection optical system is incorporated into a main body of the optical device.

The method for manufacturing a projection optical system according to claim 1, wherein the target information includes information on a pattern that is a projection target of the projection optical system.

The second step includes a step of performing a simulation for obtaining an aerial image formed on an image plane when the pattern is projected by the projection optical system based on the pattern information;
12. The step of analyzing the simulation result and determining the specification using a wavefront aberration allowed for the projection optical system as a standard value in order to transfer the pattern satisfactorily. A manufacturing method of the projection optical system.

In the simulation, the sensitivity of each term coefficient of the Zernike polynomial that develops the wavefront of the projection optical system, which is determined according to the pattern for a specific aberration when the pattern is the target pattern, and the projection optical system The method of manufacturing a projection optical system according to claim 12, wherein the aerial image is obtained based on a linear combination with a coefficient of each term of a Zernike polynomial in which the wavefront is expanded.

The projection optical system manufacturing method according to claim 1, wherein the optical apparatus is an exposure apparatus that transfers a predetermined pattern onto a substrate via the projection optical system.

A method of manufacturing a projection optical system used in an exposure apparatus,
The projection optical system is adjusted so as to shift the best focus position at a certain point in the exposure area irradiated with the illumination light for exposure within the field of the projection optical system by a predetermined amount according to the planned exposure condition. A method of manufacturing a projection optical system including the step of:

The projection optical system manufacturing method according to claim 15, wherein the exposure condition includes setting an illumination condition having a coherence factor smaller than 0.5 as an illumination condition.

The projection optical system manufacturing method according to claim 15, wherein the exposure condition includes using a phase shift mask.

An exposure apparatus for transferring a pattern formed on a mask onto a substrate via an exposure optical system,
An exposure apparatus comprising the projection optical system manufactured by the manufacturing method according to claim 1 as the exposure optical system.

An exposure apparatus for transferring a pattern onto a substrate,
A projection optical system that projects a pattern image on the substrate and whose specifications are determined using wavefront aberration as a standard value;
A wavefront measuring device for measuring the wavefront of the projection optical system;
An adjustment device that adjusts the imaging state of the pattern by the projection optical system;
An exposure apparatus comprising: a control device that controls the adjustment device using the measurement result of the wavefront.

The exposure apparatus according to claim 19, wherein the adjustment device includes an image formation characteristic adjustment mechanism that adjusts an image formation characteristic of the projection optical system.

The control device determines the sensitivity of each term of the Zernike polynomial that develops the wavefront of the projection optical system and the sensitivity of each term of the Zernike polynomial that develops the measured wavefront, which are determined according to the pattern with respect to the noted aberration. based on a linear combination of the coefficient of the term out calculate the aerial image of the pattern, on the basis of the said aerial image as the focused aberration does not exceed the allowable value, wherein the controller controls the imaging characteristic adjustment mechanism The exposure apparatus according to claim 20.

A step of manufacturing a projection optical system using the method for manufacturing a projection optical system according to any one of claims 1 to 13, 15 to 17;
Incorporating the projection optical system into an exposure apparatus main body.

A method for adjusting a projection optical system used in an exposure apparatus,
A first step of measuring the wavefront of the projection optical system whose specifications are determined using the wavefront aberration as a standard value ;
Before SL and a total measurement result, a second step for adjusting said projection optical system based on the Zernike change table corresponding to the exposure conditions of the object pattern through the projection optical system is transferred (Zernike Sensitivity); the Including a projection optical system adjustment method.

In the second step, the wavefront of the projection optical system is expanded by a Zernike polynomial so that a coefficient of a specific term selected based on the target information among coefficients of each term of the polynomial does not exceed a predetermined value. 24. The method according to claim 23, wherein the projection optical system is adjusted.

In the second step, the projection optical system is adjusted so that the RMS value of the coefficient of each term of the Zernike polynomial that develops the wavefront in the entire field of view of the projection optical system does not exceed a predetermined allowable value. 24. A method for adjusting a projection optical system according to claim 23, wherein:

In the second step, the projection optical system is adjusted so that the coefficients of the respective terms of the Zernike polynomial that develops the wavefront of the projection optical system do not exceed individually determined tolerances. Item 24. A method for adjusting a projection optical system according to Item 23.

In the second step, among the coefficients of the terms of the Zernike polynomial that develops the wavefront of the projection optical system, the RMS value within the field of the projection optical system of the coefficient of the n-th order mθ term corresponding to the particular aberration of interest 24. The projection optical system adjustment method according to claim 23, wherein the projection optical system is adjusted such that the predetermined optical tolerance does not exceed a predetermined allowable value.

In the second step, among the coefficients of each term of the Zernike polynomial that develops the wavefront of the projection optical system, each term corresponding to a specific aberration to be noted is separated into a plurality of groups for each mθ term, and each group 24. The projection optical system is adjusted so that an RMS value of a coefficient of each term included in the field of view of the projection optical system does not exceed individually determined tolerances. Adjustment method of projection optical system.

A third step of obtaining information on a pattern to be projected by the projection optical system;
The second step is based on the sensitivity of the coefficient of each term of the Zernike polynomial that develops the wavefront of the projection optical system and the measured value of the wavefront of the projection optical system, which are determined according to the pattern with respect to the noted aberration. A step of calculating a spatial image of the pattern based on a linear combination with a coefficient of each term of the Zernike polynomial obtained by developing the wavefront of the projection optical system obtained in the above; and the aberration of interest based on the spatial image is an allowable value 24. The method of adjusting a projection optical system according to claim 23, further comprising the step of adjusting the projection optical system so as not to exceed.

A third step of obtaining target information to be achieved by the exposure apparatus;
In the second step, the RMS value of the weighted coefficient of each term obtained by weighting the coefficient of each term of the Zernike polynomial that develops the wavefront of the projection optical system according to the target information does not exceed a predetermined allowable value. The projection optical system adjustment method according to claim 23, wherein the projection optical system is adjusted as described above.

31. The projection optical system adjustment method according to claim 30, wherein the target information includes information on a pattern to be projected by the projection optical system.

32. The wavefront of the projection optical system is measured in the first step based on a result of printing a predetermined pattern on a substrate through a pinhole and a projection optical system. The method for adjusting a projection optical system according to one item.

32. The wavefront of the projection optical system is measured in the first step based on an aerial image formed through a pinhole and a projection optical system. Adjustment method of projection optical system.

A method for adjusting a projection optical system used in an exposure apparatus,
When setting exposure conditions using a phase shift mask under illumination conditions with a coherence factor of less than 0.5, the best focus at some points in the exposure region irradiated with the exposure illumination light within the field of view of the projection optical system A method for adjusting a projection optical system, including a step of performing focus pre-correction that shifts a position by a predetermined amount.

The projection optical system adjustment method according to claim 34, wherein the phase shift mask is a spatial frequency modulation type phase shift mask.

36. The projection optical system adjustment method according to claim 34 or 35, wherein the focus pre-correction is performed by adjusting an aberration of the projection optical system.

A device manufacturing method including a lithography process,
In the said lithography process, it exposes using the exposure apparatus as described in any one of Claims 18-21, The device manufacturing method characterized by the above-mentioned.

A first computer connected to the exposure apparatus main body having a projection optical system for projecting a predetermined pattern onto the substrate;
An adjustment device that adjusts the imaging state of the pattern by the projection optical system;
A second computer connected to the first computer via a communication path;
The second computer calculates control information for controlling the adjustment device using a measurement result of the wavefront of the projection optical system received from the first computer via the communication path;
One of the first and second computers controls the adjustment device based on the control information.

39. The computer system according to claim 38, wherein the wavefront measurement result is input to the first computer.

A wavefront measuring device for measuring the wavefront of the projection optical system;
39. The computer system according to claim 38, wherein the measurement result of the wavefront is acquired by the first computer as a measurement result of the wavefront by the wavefront measuring apparatus.

41. The computer system according to claim 38, wherein the adjustment device includes an image formation characteristic adjustment mechanism that adjusts an image formation characteristic of the projection optical system.

The first computer also transmits information on the pattern used in the exposure apparatus main body to the second computer via the communication path,
The second computer obtains, by simulation, an aerial image formed on an image plane when the pattern is projected by the projection optical system based on the pattern information and the wavefront measurement result. Calculate the allowable aberration value of the projection optical system so as to be favorable, and calculate control information for controlling the imaging characteristic adjustment mechanism so that the aberration of interest of the projection optical system does not exceed the allowable value 42. The computer system of claim 41, wherein:

The second computer determines the sensitivity of the coefficient of each term of the Zernike polynomial that develops the wavefront of the projection optical system, which is determined according to the pattern with respect to the noted aberration, and the Zernike polynomial that develops the measured wavefront. 43. The computer system according to claim 42, wherein an aerial image of the pattern is calculated based on a linear combination with a coefficient of each term.

A plurality of the exposure apparatus main body and the first computer are provided, respectively.
A plurality of the adjustment devices are provided corresponding to the exposure apparatus main body individually,
44. The computer system according to claim 38, wherein the second computer is commonly connected to the plurality of exposure apparatus main bodies via the communication path.

The computer system according to any one of claims 38 to 44, wherein the communication path includes a local area network.

The computer system according to any one of claims 38 to 44, wherein the communication path includes a public line.

45. The computer system according to claim 38, wherein the communication path includes a wireless line.

In the second step, the coefficient of each term of the Zernike polynomial determined from the measurement result, the Zernike change table, the adjustment amount of the optical element of the projection optical system, and the change of the coefficient of each term of the Zernike polynomial 24. The adjustment amount of the optical element of the projection optical system is calculated using a least square method based on the data relating to the relationship, and the optical element is moved based on the calculated adjustment amount. A method for adjusting a projection optical system according to claim 1.

An exposure method for transferring a pattern onto an object via a projection optical system,
Adjusting the projection optical system using the adjustment method according to claim 48;
An exposure method, wherein a pattern image is generated on the object via the adjusted projection optical system under the exposure conditions.

A device manufacturing method including a lithography process,
50. A device manufacturing method, wherein in the lithography step, a circuit pattern is formed on a photosensitive object using the exposure method according to claim 49.

An exposure apparatus for transferring a pattern onto an object,
A projection optical system that projects a pattern image on the object and whose specifications are determined using wavefront aberration as a standard value;
An adjusting device for adjusting the imaging state of the pattern image on the object;
Based on the information on the wavefront aberration of the projection optical system, the Zernike change table corresponding to the pattern and its transfer condition, and the data on the relationship between the adjustment amount in the adjusting device and the coefficient of the predetermined term of the Zernike polynomial, In order to determine an adjustment amount in the adjustment device for optimizing the imaging state of the pattern image, and to transfer the pattern onto the object via the projection optical system, the determined adjustment amount is An exposure apparatus comprising: a control system that controls the adjusting device.

52. The adjustment device moves an optical element of the projection optical system, and the control system controls the movement of the optical element by the adjustment device using the determined adjustment amount. The exposure apparatus described in 1.

The adjustment device is capable of adjusting the image formation state of the pattern image by a plurality of different methods including movement of the optical element, and the control system determines the adjustment amounts in the plurality of methods, respectively. 53. The exposure apparatus according to claim 52, wherein data relating to a relationship between each of a plurality of adjustment amounts including a driving amount of the optical element and a coefficient of a predetermined term of the Zernike polynomial is used.

The exposure apparatus according to claim 53, wherein the adjustment device finely moves the object in a direction parallel to the optical axis of the projection optical system.

55. The exposure apparatus according to claim 53 or 54, wherein the adjustment device shifts a wavelength of illumination light used for generating the pattern image.

56. The exposure apparatus according to any one of claims 51 to 55, wherein the information related to the wavefront aberration is expressed as a coefficient of each term of a Zernike polynomial.

57. The exposure apparatus according to claim 56, further comprising a measurement device that measures the wavefront aberration of the projection optical system, wherein the coefficient of each term of the Zernike polynomial is determined from the measurement result as information relating to the wavefront aberration. .

The control system uses a Zernike change table different from the Zernike change table before the change in determining the adjustment amount when at least one of the pattern and the transfer condition is changed. An exposure apparatus according to claim 1.

59. The exposure apparatus according to any one of claims 51 to 58, further comprising an illumination optical system capable of changing an illumination condition of the pattern, wherein the transfer condition includes the illumination condition.

60. The exposure apparatus according to claim 59, wherein the projection optical system has a variable numerical aperture, and the transfer condition includes the numerical aperture of the projection optical system.

61. The exposure apparatus according to claim 51, wherein the control system uses a least square method for determining the adjustment amount.

In an exposure method for transferring a pattern onto an object,
Information relating to wavefront aberration of a projection optical system whose specifications are determined by using wavefront aberration as a standard value, a Zernike change table corresponding to the pattern and its transfer condition, and an apparatus for adjusting the imaging state of a pattern image on the object Determining the adjustment amount in the adjustment device for optimizing the imaging state of the pattern image, based on the data relating to the relationship between the adjustment amount in the Zernike polynomial and the coefficient of the predetermined term of the Zernike polynomial,
In order to transfer the pattern onto the object via the projection optical system, the exposure state is adjusted by the adjustment device using the determined adjustment amount. .

63. The image formation state of the pattern image is adjusted by the movement of the optical element of the projection optical system by the adjustment device, and the optical element is moved using the determined adjustment amount. Exposure method.

In order to determine the adjustment amount in each of the plurality of methods, the imaging state of the pattern image is adjusted by a plurality of different methods of the adjusting device including the movement of the optical element, and includes the driving amount of the optical element. 64. The exposure method according to claim 63, wherein data relating to a relationship between each of the plurality of adjustment amounts and a coefficient of a predetermined term of the Zernike polynomial is used.

The exposure method according to claim 64, wherein the plurality of methods include movement of the object in a direction parallel to an optical axis of the projection optical system.

66. The exposure method according to claim 64 or 65, wherein the plurality of methods include a shift in wavelength of illumination light used for generating the pattern image.

67. The exposure method according to any one of claims 62 to 66, wherein the information on the wavefront aberration is expressed as a coefficient of each term of a Zernike polynomial.

68. The exposure method according to claim 67, wherein the coefficient of each term of the Zernike polynomial is determined from the measurement result of the wavefront aberration of the projection optical system as information relating to the wavefront aberration.

69. When at least one of the pattern and the transfer condition is changed, a Zernike change table different from the Zernike change table before the change is used in the determination of the adjustment amount. An exposure method according to 1.

70. The exposure method according to any one of claims 62 to 69, wherein the transfer condition includes an illumination condition of the pattern.

The exposure method according to claim 70, wherein the transfer condition includes a numerical aperture of the projection optical system.

The exposure method according to any one of claims 62 to 71, wherein a least square method is used in determining the adjustment amount.

In a device manufacturing method including a lithography process,
73. A device manufacturing method, wherein in the lithography step, a pattern is formed on an object using the exposure method according to any one of claims 62 to 72.