CN101135864A - Exposure method and apparatus and device manufacturing method - Google Patents

Exposure method and apparatus and device manufacturing method Download PDF

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Publication number
CN101135864A
CN101135864A CNA2007101547932A CN200710154793A CN101135864A CN 101135864 A CN101135864 A CN 101135864A CN A2007101547932 A CNA2007101547932 A CN A2007101547932A CN 200710154793 A CN200710154793 A CN 200710154793A CN 101135864 A CN101135864 A CN 101135864A
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optical system
projection optical
imaging characteristic
pattern
zelnick
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塚越敏雄
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Nikon Corp
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Nikon Corp
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Abstract

The present invention discloses an exposal method for transfer printing pattern to object through a projecting optical system, to regulate the imaging speciality of the projecting optical system, and to project the pattern image to the object by the projecting optical system after regulating image speciality, according to the information about the wave front aberration of the projecting optical system, the pattern to transfer print on the object and the zelnik change table corresponding to the lighting condition of the pattern, as well as the correlative data of the change relation of zelnik multinomial parameter change and the regulation amount for regulating the projecting optical system imaging speciality.

Description

Exposure method and equipment and device making method
The explanation of dividing an application
The application is that application number is 01821648.X, the applying date to be that Dec 27 calendar year 2001 and denomination of invention are the dividing an application of Chinese patent application of " imaging characteristics measuring method, imaging characteristics adjusting method, exposure method and equipment, program and storage medium and device making method ".
Technical field
The present invention relates to imaging characteristics measuring method, imaging characteristics adjusting method, exposure method and equipment, program and storage medium and device making method, and relate in particular to a kind of imaging characteristics measuring method of measuring the target imaging characteristic of projection optical system, regulate the imaging characteristics adjusting method of imaging characteristic, exposure method that the projection optical system of utilizing imaging characteristic imaging characteristics adjusting method according to the present invention to regulate is exposed and the exposure sources that is suitable for carrying out imaging characteristics adjusting method, make the control computer of exposure sources carry out calculate and regulate the program of processing of projection optical system target imaging characteristic and information storage medium and a kind of device making method that utilizes exposure sources that stores this program and can read by computer.
Background technology
Use apparatus for projection exposure during routinely with photoetching process manufacturing such as devices such as semiconductor, LCD, as based on multiple scanning method (so-called ledex) dwindle exposure sources and based on the scanning projection exposure sources of step-scan method (so-called scanning ledex).For this apparatus for projection exposure, by projection optical system be formed on pattern transfer to a substrate on photomask or the graticule (following general designation " graticule "), as on the glass plate that is coated with photochromics such as photoresist.
When making semiconductor devices,, before be formed on the substrate each and taken on the pattern in the district very important so the graticule that is formed with circuit pattern on it accurately overlapped onto because different circuit patterns need have multilayer on a substrate.For good overlay accuracy is arranged, the imaging characteristic of projection optical system need be adjusted to desirable state (for example the transferred image of graticule pattern has obtained proofreading and correct with respect to the fault in enlargement in each shooting district (pattern) on the substrate).Even, also preferably regulate the imaging characteristic of projection optical system when the graticule pattern transfer of ground floor each shooting Qu Shangshi to substrate, the graticule pattern that makes the second layer reach floor upwards can accurately be transferred to each and take the district.
As a prerequisite of the imaging characteristic (a kind of optical characteristics) of regulating projection optical system, need accurately to measure (or detection) imaging characteristic.As the measuring method of imaging characteristic, mainly adopt the method (below be called " exposure method ") of computational imagery characteristic.In the method, utilize a measurement mask that is formed predetermined measured pattern on it to expose, measure the image of a transfer printing, as the resist image that obtains by substrate developing to the projection image that is transferred and forms measured pattern on it.Then, according to measurement result computational imagery characteristic, five kinds of aberrations of Sai Deer (distortion, spherical aberration, astigmatism, field curvature and coma) specifically.Except that the method, also use a kind of unactual method (" spatial image mensuration ") of exposing and calculating above-mentioned five kinds of aberrations.In the method, throw light on to measuring mask with illumination light, and measure the spatial image (projection image) of the measured pattern that forms by projection optical system, and then calculate above-mentioned five kinds of aberrations according to measurement result.
But,, must utilize every kind of suitable pattern of measurement is repeated above-mentioned measurement individually in order to obtain five kinds of aberrations for above-mentioned exposure method or spatial image mensuration.In addition, also must consider to carry out the order of measuring, so that accurately regulate projection optical system according to the type and size of aberration to be measured.For example, when coma is big, just can not offer an explanation the image of pattern, therefore when measuring aberration such as distortion, spherical aberration and astigmatism in this state, just can not obtain accurate data.Thereby in this case, need before the measurement that distorts etc., coma be reduced to a specific level.
In addition, because higher integrated level such as semiconductor devices in recent years, it is thinner that circuit pattern becomes.Therefore it is not enough only to proofread and correct five kinds of aberrations of Sai Deer, need carry out total adjusting to the projection optical system imaging characteristic, comprises higher order aberrations.For imaging characteristic being carried out this total adjusting, need to carry out ray trajectory and calculate and calculate the lens element that needs adjusting and their regulated quantity by the data (as curvature, refractive index and thickness) of utilizing each lens of forming projection optical system.
But, because the data of each lens element are for secret of the Lai Shuoshi of manufacturer of exposure sources, so be difficult to the repairing of service technician usually or regulate exposure sources or the user obtains these data.In addition, because the calculating of ray trajectory needs a large amount of time, so calculate very unrealistic then and there for service technician.
In addition, the aberration of projection optical system is to the difference that influences of the imaging characteristic of various patterns, and this also makes the user of exposure sources according to the type for the treatment of projection pattern different requirements be arranged.For example, contact hole pattern especially is subject to the influence of astigmatism.Row-the intermittent pattern that has the hachure width is subjected to the coma image very big, and the optimal focus position of the line image of for example isolating and row-intermittent pattern is different.
In this case, wish to have a kind of new technology, can make the operator of semiconductor factory simply and accurately carry out the measurement of projection optical system imaging characteristic (a kind of optical characteristics) as a kind of, especially degree of accuracy had the imaging characteristic (aberration) of significant impact when measuring the main body pattern transfer is estimated during to substrate; Or a kind of so new technology, can make the service technician etc. of semiconductor factory the imaging characteristic of projection optical system relatively simply be reached the adjusting of pinpoint accuracy.
Summary of the invention
Proposed the present invention under these circumstances, and first purpose of the present invention is to provide a kind of imaging characteristics measuring method, this method can simple and easy and accurately be measured the target imaging characteristic of projection optical system.
Second purpose of the present invention is to provide a kind of imaging characteristics adjusting method, can simple and easy and accurately regulate the imaging characteristic of projection optical system.
The 3rd purpose of the present invention is to provide a kind of exposure method, and this exposure method can be formed into meticulous pattern on the substrate with good precision.
The 4th purpose of the present invention is to provide a kind of exposure sources, this equipment can with good precision with the pattern transfer on the mask to substrate.
The 5th purpose of the present invention is to provide a kind of device making method, and this method helps to improve the throughput rate of device.
The 6th purpose of the present invention is to provide a kind of information storage medium that is suitable for being used in the program in each exposure sources and stores this program and can be read by computing machine.
According to a first aspect of the invention, a kind of imaging characteristics measuring method of measuring an imaging characteristic of projection optical system at least is provided, this method comprises: measuring process, measure the wavefront aberration of projection optical system in the measurement point of projection optical system at least one; And computation process, calculate at least one target imaging characteristic according to Zelnick (zernike) argument table of target imaging characteristic of the measurement of wavefront aberration and preparation in advance.
" target imaging characteristic " is a notion that comprises target imaging characteristic and index thereof in the case.In this article, " target imaging characteristic " is used for this meaning.
In the method, after at least one measurement point of projection optical system field is measured the wavefront aberration of projection optical system, according to the aberration that records and the Zelnick argument table calculating target imaging characteristic of the imaging characteristic of preparation in advance.By preparing the Zelnick argument table in this way in advance, can just can calculate the target imaging characteristic by an one-shot measurement wavefront aberration.In the case, because wavefront aberration is measured, wherein this aberration is total imaging characteristic of projection optical system, so can obtain the target imaging characteristic with good degree of accuracy.
In the case, in computation process, when the target imaging characteristic comprises polytype imaging characteristic, can calculate the multiclass imaging characteristic that is included in the target imaging characteristic respectively according to the measurement of wavefront aberration and to the Zelnick argument table of each class of multiclass imaging characteristic.
For imaging characteristics measuring method of the present invention, can after considering various patterns, make the Zelnick argument table of imaging characteristic separately to various imaging characteristics, perhaps this method also comprises: manufacturing process, before measuring process, according to will imposing a condition making the Zelnick argument table by the information of projection optical system projected pattern main body and target imaging characteristic, and according to information that relates to projection optical system and the Zelnick argument table that relates to the information issuing of the given aberration target imaging characteristic corresponding with the information that relates to given aberration.Under one situation of back, the information that relates to projection optical system can comprise the numerical aperture of projection optical system, lighting condition and illumination light wavelength.
For imaging characteristics measuring method of the present invention, when before measuring process, making the Zelnick argument table, in manufacturing process, when the target imaging characteristic comprises polytype imaging characteristic, can make corresponding with the information that relates to aberration about each Zelnick argument table of multiclass imaging characteristic.
For imaging characteristics measuring method of the present invention, can also comprise: a procedure for displaying shows the information that relates to the target imaging characteristic of having been calculated.
According to a second aspect of the invention, a kind of first imaging characteristics adjusting method of regulating an imaging characteristic of projection optical system at least is provided, this method comprises: measuring process, and utilize imaging characteristics measuring method as claimed in claim 1 to measure at least one target imaging characteristic; And adjustment process, regulate projection optical system according to the measurement result of target imaging characteristic.
In the adjusting method, because utilize imaging characteristics measuring method of the present invention to measure at least one target imaging characteristic, so can obtain the target imaging characteristic with good degree of accuracy; And regulate projection optical system according to the imaging characteristic (measurement result of imaging characteristic) that obtains.Therefore, can regulate the target imaging characteristic of projection optical system with good degree of accuracy.For example imaging characteristic (aberration) the decision target imaging characteristic by being formed by the special image that influences the main body pattern can be regulated the imaging characteristic of projection optical system as much as possible according to the main body pattern.
In the case, the projection optical system that can constitute comprises a plurality of optical elements, these elements comprise the particular optical element that is used to regulate, and can determine the target regulated quantity of particular optical element by the calculating of the relational expression between the target regulated quantity of utilizing the imaging characteristic, parameter and the particular optical element that have recorded, and, concern between the variation of the adjusting of parametric representation particular optical element and projection optical system imaging characteristic by the particular optical element that is used to regulate being regulated the adjusting of carrying out projection optical system according to the target regulated quantity of decision.
According to a third aspect of the invention we, a kind of second imaging characteristics adjusting method of regulating at least one imaging characteristic of projection optical system is provided, wherein this projection optical system comprises a plurality of optical elements, comprise a particular optical element that is used to regulate in a plurality of optical elements, this method comprises: acquisition process obtains a measurement point at least one of projection optical system about the information of light by projection optical system; And decision process, decide the target regulated quantity of particular optical element, the wherein relation between the variation of the imaging characteristic of the regulated quantity of this parametric representation particular optical element and projection optical system by the calculating of the relational expression between the target regulated quantity of utilizing imaging characteristic, parameter and the particular optical element obtained.
In the case " particular optical element that is used to regulate " expression be used to regulate imaging characteristic particular optical element, except regulating the situation of imaging characteristic of projection optical system, also comprise such as by the situation of handling again or the exchange particular optical element is regulated imaging characteristic by driving or changing particular optical element.That is, except regulating (correction) imaging characteristic in the adjusting stage, comprise also that for " adjusting " of particular optical element the projection optical system itself that imaging characteristic is conditioned regulates.In addition, in fact, the particular optical element that is used to regulate is not limited to one, can be a plurality of.In this instructions, " particular optical element that is used to regulate " contains this kind meaning.
In addition, when the particular optical element that is used to regulate when being a plurality of, " target regulated quantity " comprises that regulated quantity is zero situation, the situation of promptly not regulating.In this instructions, " target regulated quantity " contains this kind meaning.
In the method, when regulating projection optical system, obtain a measurement point at least one of projection optical system about the information of light by projection optical system, and obtain imaging characteristic.And by calculating, relational expression between the parameter that concerns between the regulated quantity of the imaging characteristic that utilization has obtained, expression particular optical element and the variation of projection optical system imaging characteristic and the target regulated quantity of particular optical element, with the target regulated quantity as unknown-value, by calculating decision this unknown-value, i.e. the target regulated quantity of particular optical element.In this mode, relational expression between the parameter that concerns between the adjusting of the actual measured results by utilizing imaging characteristic (aberration), expression particular optical element and the variation of projection optical system imaging characteristic and the target regulated quantity of particular optical element can be calculated the target regulated quantity of the particular optical element that is used to proofread and correct imaging characteristic at an easy rate.This makes can regulate the imaging characteristic of projection optical system accurately in simple mode.
In the case, this method also comprises an acquisition process, before the acquisition process that obtains imaging characteristic, obtains this parameter.
For second imaging characteristics adjusting method of the present invention, the imaging characteristic that regulate can be an imaging characteristic, and perhaps imaging characteristic can comprise polytype imaging characteristic.Under the latter event, in the acquisition process that obtains imaging characteristic, can obtain polytype imaging characteristic, and in decision process, can decide the target regulated quantity of particular optical element by the calculating of the relational expression between the target regulated quantity of utilizing the multiclass imaging characteristic, parameter and the particular optical element that have obtained, wherein the relation between the variation of the imaging characteristic of the adjusting of parametric representation particular optical element and projection optical system.
For second imaging characteristics adjusting method of the present invention, the imaging characteristic that regulate can be various imaging characteristics, and can consider the various relational expressions corresponding with these imaging characteristics.For example, imaging characteristic can be to be expressed as the polynomial wavefront aberration of Zelnick.
In the case, this relational expression can be an equation that comprises weighting function, and weighting function is weighted the coefficient of each in the Zelnick polynomial expression.
According to a forth aspect of the invention, provide a kind of and the pattern transfer that is formed on the mask is arrived on-chip exposure method by projection optical system, this exposure method comprises: an adjustment process, and utilize according to the imaging characteristics adjusting method of any one in aforementioned first and second imaging characteristics adjusting methods and regulate at least one imaging characteristic of projection optical system; With a transfer process, utilize the adjusted projection optical system of imaging characteristic pattern transfer to substrate.
In the method, utilize in the present invention first or second imaging characteristics adjusting method any one to regulate the imaging characteristic of projection optical system, and by the adjusted projection optical system of imaging characteristic the pattern transfer of mask to substrate.Therefore, mask pattern is transferred on the substrate, good precision can be arranged so be formed into on-chip fine pattern because obtain the projection optical system that high precision regulates by imaging characteristic.
Especially when utilizing first imaging characteristics adjusting method of the present invention to regulate projection optical system, can regulate the target imaging characteristic as much as possible, for example, especially influence the imaging characteristic of main body pattern imaging.Therefore, even when utilizing one to be formed with fine pattern on it and to expose as the mask of main body pattern, also can by such projection optical system pattern transfer to substrate, promptly the imaging characteristic that especially influences the fine pattern imaging (aberration) of this projection optical system is regulated as much as possible.
According to a fifth aspect of the invention, provide a kind of and the pattern transfer that is formed on the mask has been arrived on-chip first exposure sources by projection optical system, this exposure sources comprises: a measuring unit, measure the wavefront aberration of projection optical system, this measuring unit is attached to the exposure sources main body that comprises projection optical system at least in part; With one first computing unit, calculate at least one target imaging characteristic according to the wavefront aberration of the projection optical system of measuring by the Zelnick argument table of measuring unit and target imaging characteristic.
In this equipment, when measuring unit was measured the wavefront aberration of projection optical system, first computing unit calculated the target imaging characteristic according to the wavefront aberration of the projection optical system of calculating and the Zelnick argument table of target imaging characteristic.In this mode,, can only measure wavefront aberration and calculate the target imaging characteristic by utilizing the Zelnick argument table.In the case, because wavefront aberration is measured, and wavefront aberration is the overall imaging characteristic of projection optical system, so can obtain the target imaging characteristic with good degree of accuracy.And (for example, the difference minimum between the target value expose under) the state, can mask pattern be transferred on the substrate with good degree of accuracy by becoming the best at the target imaging characteristic that obtains with good degree of accuracy.
In the case, first exposure sources can also comprise a storage unit that stores the Zelnick argument table in advance.
About first exposure sources of the present invention, the Zelnick argument table can be a relevant corresponding target imaging characteristic Zelnick argument table of information of given aberration during with the main body pattern exposure.
According to first exposure sources of the present invention, can also comprise: one is used to import and comprises main body pattern-information, target imaging characteristic information, the information relevant with projection optical system and about the input block of the various information of the information of given aberration; With one second computing unit, condition is set so that according to the information of main body pattern of importing through input block and target imaging characteristic and according to information of importing through input block relevant and the information issuing Zelnick argument table relevant with given aberration with projection optical system, second computing unit is made the Zelnick argument table of a target imaging characteristic, and the information of given aberration is corresponding during with the main body pattern exposure.
In the case, relevant with projection optical system information can comprise numerical aperture, lighting condition and the illumination light wavelength of projection optical system.
First exposure sources according to the present invention can also comprise a display unit, shows the information of the target imaging characteristic of calculating about first computing unit on display screen.
First exposure sources of the present invention can also comprise an imaging characteristic correcting unit, proofreaies and correct at least one imaging characteristic of projection optical system according to the target imaging characteristic result of calculation of first computing unit.
In the case, the projection optical system that constitutes can comprise a plurality of optical elements, these a plurality of optical elements comprise a particular optical element that is used to regulate, the imaging characteristic correcting unit can have a storage unit of storage parameter in advance, the relation between the adjusting of the parametric representation particular optical element of storage and the variation of projection optical system imaging characteristic; With a computing unit, the relational expression between the target regulated quantity of information, parameter and the particular optical element of the imaging characteristic that utilization has been calculated calculates the target regulated quantity of particular optical element.
According to a sixth aspect of the invention, provide a kind of and the pattern transfer that is formed on the mask has been arrived on-chip second exposure sources through projection optical system, this exposure sources comprises: comprise the projection optical system of a plurality of optical elements, comprise a particular optical element that is used to regulate in wherein a plurality of optical elements; A storage unit that shifts to an earlier date storage parameter, the relation between the variation of the adjusting of parametric representation particular optical element and projection optical system imaging characteristic; A measuring unit, at least one imaging characteristic of measurement projection optical system, measuring unit is attached to the exposure sources main body that comprises projection optical system at least in part; With a computing unit, utilize relational expression between the target regulated quantity of actual measurement data, parameter and particular optical element that measuring unit records to calculate the target regulated quantity of particular optical element.
In this equipment, obtain the parameter of the relation between the variation of the adjusting of the adjustable particular optical element of expression and projection optical system imaging characteristic in advance and it is stored in storage unit.And when the imaging characteristic of measuring unit actual measurement projection optical system, computing unit utilizes the relational expression between the target regulated quantity of actual measurement data, above-mentioned parameter and particular optical element of imaging characteristic to calculate the target regulated quantity of particular optical element.As mentioned above, because above-mentioned parameter obtains in advance and is stored in the storage unit, so when actual measurement imaging characteristic (aberration), can calculate the target regulated quantity that particular optical element is used to proofread and correct imaging characteristic at an easy rate, and by regulate particular optical element according to result of calculation, can be simply and regulate the imaging characteristic of projection optical system accurately.Therefore, expose by utilizing imaging characteristic to obtain the projection optical system that high precision regulates, can through projection optical system with the pattern pinpoint accuracy of mask be transferred on the substrate.
In the case, can regulate by the target regulated quantity of the particular optical element of calculating more than the manual foundation of operator, perhaps for example, second exposure sources can also comprise an imaging characteristic regulon, regulates at least one imaging characteristic of projection optical system by regulating particular optical element according to the target regulated quantity of calculating.
About second exposure sources of the present invention, the imaging characteristic that be conditioned can be a kind of imaging characteristic, but this imaging characteristic can comprise polytype imaging characteristic.Under latter event, measuring unit can be measured the imaging characteristic of multiclass projection optical system, and computing unit can utilize relational expression between the target regulated quantity of actual measurement data, parameter and particular optical element of the multiclass imaging characteristic that measuring unit records to calculate the target regulated quantity of particular optical element.
About second exposure sources of the present invention, the imaging characteristic that be conditioned can be various types of imaging characteristics, and can consider the various relational expressions corresponding with these imaging characteristics.For example, imaging characteristic can be to be expressed as the polynomial wavefront aberration of Zelnick.
In the case, this relational expression can be an equation that comprises weighting function, and weighting function is weighted the coefficient of each in the Zelnick polynomial expression.
According to a seventh aspect of the invention, a kind of first program is provided, this program makes by projection optical system the control computer that mask pattern is transferred to on-chip exposure sources is carried out a predetermined processing, this program makes control computer carry out: the condition setting program, for to making the Zelnick argument table condition being set in response to the information input that relates to main body pattern-information and target imaging characteristic information; And production process, in response to the input of the information of information that relates to projection optical system and given aberration, make the Zelnick argument table of a target imaging characteristic corresponding with the information of the given aberration of main body pattern exposure.
When in the control computer that program is installed to exposure sources, by to the computing machine input about the information of main body pattern with relate to the information of target imaging characteristic, be implemented as the condition setting of making the Zelnick argument table in response to this input by computing machine.Next, information by the computing machine input of finishing these condition setting being related to projection optical system and about the information of given aberration, in response to this input, the Zelnick argument table of the target imaging characteristic that the information of one of the computer manufacture given aberration during with the main body pattern exposure is corresponding.Promptly, by only computing machine input being made the necessary minimum information of Zelnick argument table, as about the information of main body pattern, relate to the target imaging characteristic information, relate to the information of projection optical system and, just can make target imaging characteristic Zelnick argument table at an easy rate corresponding to the given aberration of exposure of main body pattern about the information of given aberration.The Zelnick argument table of Zhi Zuoing also can be used to comprise other exposure sources of similar projection optical system thus.
Set up in the above described manner after the Zelnick argument table, this program can also make control computer carry out calculation procedure, according to actual measurement data and Zelnick argument table, in response to the input of the actual measurement data of projection optical system wavefront aberration, calculate the target imaging characteristic of projection optical system.In the case, in response to this input, by the wavefront aberration actual measurement data of further input projection optical system, computing machine calculates the target imaging characteristic of projection optical system according to real data and Zelnick argument table.Therefore, only, just can accurately calculate the target imaging characteristic in the short time by computing machine by importing the wavefront aberration actual measurement data of one-shot measurement acquisition at least.
About first program of the present invention, this program can also make control computer carry out display routine, shows the information of the target imaging characteristic of having calculated on display unit.
About first program of the present invention, this program can also make control computer carry out the adjusting program, regulates projection optical system, makes the target imaging characteristic of having calculated become the best (for example, the difference minimum of target value).
About first program of the present invention, when except making above-mentioned Zelnick argument table, also calculating the target imaging characteristic, this program can also make control computer carry out: production process, in response to the input of the different information that relate to projection optical system and the input of given aberration information, by relating to each different information issuing Zelnick argument table of projection optical system; Calculation procedure, in response to the input of the wavefront aberration actual measurement data of projection optical system, according to actual measurement data and Zelnick argument table, the target imaging characteristic of each the different information calculations projection optical system by relating to projection optical system; And determination procedure, by finding the information decision optimum exposure condition that relates to projection optical system, this optimum exposure condition makes the target imaging characteristic of having calculated become the best (for example, the difference of target value becomes minimum).
In the case, this program can also make control computer carry out setting program, and the optimum exposure condition that has determined is set.
According to an eighth aspect of the invention, a kind of second program is provided, this program is carried out control computer: calculation procedure, according to the actual measurement data and the Zelnick argument table of target imaging characteristic of preparation in advance, calculate the target imaging characteristic of projection optical system in response to the input of the actual measurement data of information input that relates to the target imaging characteristic and projection optical system wavefront aberration.
When in the control computer that this program is installed to exposure sources, by relating to the information of target imaging characteristic and the actual measurement data of projection optical system wavefront aberration is input in the computing machine, this computing machine is in response to input, according to actual measurement data and the Zelnick argument table of the target imaging characteristic of the preparation target imaging characteristic of calculating projection optical system in advance.In this case, comprise that the control computer of other exposure sources of similar projection optical system can be used the Zelnick argument table, this table is the Zelnick argument table that utilizes the target imaging characteristic of first program making of the present invention.Therefore, only the wavefront aberration actual measurement data that relates to the information of target imaging characteristic and obtain in the one-shot measurement at least by input just can accurately be calculated the target imaging characteristic by computing machine in the short time.In the case, the imaging characteristic that for example preferably will greatly influence the imaging of main body pattern is elected the target imaging characteristic as.
About second program of the present invention, this program can also make control computer carry out display routine, shows the information of the target imaging characteristic of having calculated on display unit.
About second program of the present invention, this program can also make control computer carry out the adjusting program, regulates projection optical system, makes the target imaging characteristic of having calculated become the best.
According to a ninth aspect of the invention, one the 3rd program is provided, this program makes by projection optical system the control computer that mask pattern is transferred to on-chip exposure sources is carried out a predetermined processing, this program makes control computer carry out: calculation procedure, input in response to the actual measured value of projection optical system imaging characteristic, utilize the imaging characteristic actual measured value of having imported, relational expression between the target regulated quantity of parameter and projection optical system calculates the target regulated quantity of projection optical system, the wherein relation between the variation of the adjusting of parametric representation projection optical system and projection optical system imaging characteristic.
About this program, in advance this program is installed in the control computer of exposure sources.And when importing the actual measurement data of projection optical system imaging characteristic, the relational expression between the parameter that concerns between the adjusting of the actual measurement data that the control computer utilization of exposure sources has been imported, expression projection optical system and the variation of projection optical system imaging characteristic and the target regulated quantity of projection optical system calculates the target regulated quantity.That is, operator etc. only need the actual measured value of actual measurement imaging characteristic (aberration) and input imagery characteristic to calculate the target regulated quantity of projection optical system, so that proofread and correct imaging characteristic.Therefore, for example by regulating projection optical system according to the target regulated quantity of calculating, high precision is regulated the imaging characteristic of projection optical system at an easy rate.
In the case, this program can also make control computer carry out display routine, shows the information of the target regulated quantity of having calculated on display unit.
About the 3rd program of the present invention, this program can also make control computer carry out the adjusting program, regulates projection optical system according to the target regulated quantity of having calculated.
About the 3rd program of the present invention, this parameter can be the parameter of the relation between the variation of the adjusting of the expression particular optical element that is used to regulate that constitutes projection optical system and imaging characteristic, and the target regulated quantity can be the amount that particular optical element need be regulated.
About the 3rd program of the present invention, imaging characteristic can be to be expressed as the polynomial wavefront aberration of Zelnick.
In the case, relational expression can be an equation that comprises weighting function, to each the coefficient weighting of Zelnick polynomial expression.
About the 3rd program of the present invention, this program can also make control computer carry out: the condition setting program is provided with condition in response to the information input of information input that relates to the main body pattern-information and target imaging characteristic to making the Zelnick argument table; Production process in response to the input of the information of information that relates to projection optical system and given aberration, is made the Zelnick argument table of a target imaging characteristic corresponding with aberration information; And calculation procedure, according to measurement data and Zelnick argument table,, calculate the target imaging characteristic in response to the input of the actual measurement data of projection optical system wavefront aberration.
About the 3rd program of the present invention, this program can also make control computer carry out display routine, shows the information of the target imaging characteristic of having calculated on display unit.
About the 3rd program of the present invention, this program can also make control computer carry out converse routine, the actual measurement data that is transformed into the projection optical system wavefront aberration by the projection optical system information that a measurement point at least one obtains at it.
According to the tenth aspect of the invention, provide a kind of the 3rd imaging characteristics adjusting method of regulating an imaging characteristic of projection optical system at least, this method comprises: measuring process, measure the information relevant with the wavefront aberration of projection optical system; And the data that concern between the variation according to the regulated quantity of optical element and each coefficient of Zelnick polynomial expression and with wavefront aberration relevant information, regulate imaging characteristic by the optical element that drives projection optical system.
By this method, when regulating at least one imaging characteristic of projection optical system, the data that concern between the variation according to the optical element regulated quantity of information relevant with wavefront aberration that records and projection optical system and each coefficient of Zelnick polynomial expression are measured the information relevant with the wavefront aberration of projection optical system, and regulate imaging characteristic by driving this optical element.In the case, can calculate the optical element target regulated quantity that is used to proofread and correct the projection optical system imaging characteristic at an easy rate according to the optical element regulated quantity of projection optical system and the variation and the information relevant of each coefficient of Zelnick polynomial expression with the wavefront aberration that records.Therefore, can regulate the imaging characteristic of projection optical system at an easy rate with high precision.
According to an eleventh aspect of the invention, provide a kind of by projection optical system the exposure method of pattern transfer to the object, this method comprises measuring process, measures the information relevant with the wavefront aberration of projection optical system; Computation process, according to the information relevant and by to each aberration value of being scheduled to of Zelnick polynomial expression and calculate the Zelnick argument table that the target imaging characteristic of each middle projection optical system of Zelnick polynomial expression obtains, each conditions of exposure that can be provided with is calculated target imaging characteristic when the projection optical system projection pattern with wavefront aberration; And transfer process, according to the target imaging characteristic about each conditions of exposure of having calculated, utilize optimum exposure condition about pattern setting pattern transfer to object.
By this method, before exposure, measure the information relevant with the wavefront aberration of projection optical system, and, each conditions of exposure that can be provided with is calculated target imaging characteristic when the projection optical system projection pattern according to the information relevant and by to each aberration value of being scheduled to of Zelnick polynomial expression and calculate the Zelnick argument table that the target imaging characteristic of each middle projection optical system of Zelnick polynomial expression obtains with aberration.And when exposing,, be this pattern setting top condition according to the target imaging characteristic that each conditions of exposure is calculated, and with pattern transfer to object.Therefore because under top condition, expose, so even when this pattern is a meticulous pattern, also can with good precision it be transferred on the object according to this pattern.
According to a twelfth aspect of the invention, provide a kind of by projection optical system three exposure sources of pattern transfer to the object, this exposure sources comprises: a computing unit, according to the information relevant and by to each aberration value of being scheduled to of Zelnick polynomial expression and calculate the Zelnick argument table that the target imaging characteristic of each middle projection optical system of Zelnick polynomial expression obtains, obtain the target imaging characteristic with the wavefront aberration of projection optical system; And regulon, regulate at least one imaging characteristic of projection optical system according to one of the information relevant and the target imaging characteristic of having calculated with wavefront aberration.
By this equipment, computing unit obtains the target imaging characteristic according to the information relevant with the wavefront aberration of projection optical system and by target imaging characteristic that calculates each middle projection optical system of Zelnick polynomial expression and the Zelnick argument table that each aberration value of being scheduled to of Zelnick polynomial expression is obtained.And regulon is regulated the imaging characteristic of projection optical system according to information relevant with wavefront aberration or the imaging characteristic of having calculated.Therefore, can regulate the imaging characteristic that comprises the high-order composition of projection optical system with good precision according to the information relevant, and regulate, carry out the correction of target imaging characteristic with good precision with wavefront aberration.In either case, by utilize the projection optical system regulated pattern transfer to object, can with good precision with meticulous pattern transfer to object.
According to a thirteenth aspect of the invention, provide a kind of by projection optical system four exposure sources of pattern transfer to the object, this exposure sources comprises: storage unit, store with projection optical system in relevant data of relation between each the index variation in the regulated quantity of optical element and the Zelnick polynomial expression; And regulon, regulate at least one imaging characteristic of projection optical system according to information relevant and data with the wavefront aberration of projection optical system.
By this equipment, regulon is regulated the imaging characteristic of projection optical system according to relevant data of the relation between each the index variation in the regulated quantity of optical element in the projection optical system and the Zelnick polynomial expression and the information relevant with the wavefront aberration that is stored in the projection optical system in the storage unit.In the case, because be used for proofreading and correct the target regulated quantity of the optical element of projection optical system imaging characteristic be easy to according to the relevant data of the relation between each the index variation in the regulated quantity of projection optical system optical element and the Zelnick polynomial expression and with wavefront aberration relevant information (as the measured value of wavefront aberration) calculate, so high precision is regulated the imaging characteristic of projection optical system at an easy rate.And by utilizing the projection optical system regulated to expose, thus can with very high precision pattern transfer to object.
According to a fourteenth aspect of the invention, provide a kind of by projection optical system five exposure sources of pattern transfer to the object, this exposure sources comprises: a computing unit, according to the information relevant and by to each aberration value of being scheduled to of Zelnick polynomial expression and calculate the Zelnick argument table that the target imaging characteristic of each middle projection optical system of Zelnick polynomial expression obtains, obtain the target imaging characteristic when a plurality of conditions of exposure that can be provided with about the projection optical system projection pattern with the wavefront aberration of projection optical system; With the exposure control module, about the target imaging characteristic of each conditions of exposure the optimum exposure condition of pattern is set according to what calculated.
By this equipment, computing unit calculates target imaging characteristic about a plurality of conditions of exposures that can be provided with according to the information relevant with the wavefront aberration of projection optical system and the target imaging characteristic by calculating each middle projection optical system of Zelnick polynomial expression and to the Zelnick argument table that each aberration value of being scheduled to of Zelnick polynomial expression obtains with the projection optical system projection pattern time.And the exposure control module is provided with the optimum exposure condition of pattern according to what calculated for the target imaging characteristic of each conditions of exposure.In this way, under the top condition corresponding, expose with pattern, therefore, even when pattern is a kind of fine pattern, also can with good precision pattern transfer to object.
According to a fifteenth aspect of the invention, a kind of quadruple pass preface that makes the control computer execution predetermined process of exposure sources is provided, wherein this exposure sources by projection optical system the pattern transfer of mask to object, this program is carried out control computer: process of measurement, measure the information relevant with the wavefront aberration of projection optical system; With the adjusting program, according to the data of the relation between the variation of the regulated quantity of optical element and each coefficient of Zelnick polynomial expression and with wavefront aberration relevant information, regulate at least one imaging characteristic by the optical element that drives projection optical system.
According to a sixteenth aspect of the invention, a kind of the 5th program that makes the control computer execution predetermined process of exposure sources is provided, wherein this exposure sources by projection optical system the pattern transfer of mask to object, this program is carried out control computer: process of measurement, measure the information relevant with the wavefront aberration of projection optical system; Calculation procedure, according to the information relevant and by to each aberration value of being scheduled to of Zelnick polynomial expression and calculate the Zelnick argument table that the target imaging characteristic of each middle projection optical system of Zelnick polynomial expression obtains, each conditions of exposure that can be provided with is calculated target imaging characteristic when the projection optical system projection pattern with the wavefront aberration of projection optical system; With the transfer printing program, according to the target imaging characteristic about each conditions of exposure of having calculated, utilize optimum exposure condition about pattern setting pattern transfer to object.
According to a seventeenth aspect of the invention, a kind of the 6th program that makes the control computer execution predetermined process of exposure sources is provided, wherein this exposure sources by projection optical system the pattern transfer of mask to object, this program is carried out control computer: acquisition process, according to the information relevant and by to each aberration value of being scheduled to of Zelnick polynomial expression and calculate the Zelnick argument table that the target imaging characteristic of each middle projection optical system of Zelnick polynomial expression obtains, obtain the target imaging characteristic with the wavefront aberration of projection optical system; With the adjusting program, according to wavefront aberration and the information relevant with the imaging characteristic of having calculated, regulate at least one imaging characteristic of projection optical system.
First to the 6th program of the present invention can be stored in the storage medium.Therefore, according to an eighteenth aspect of the invention, provide a kind of information storage medium, this medium can be by in computing machine playback record first to the 6th program therein any one.
In addition, in photoetching process, expose by utilizing one in the present invention's first to the 5th exposure sources, with good precision pattern transfer to substrate, make and can make the high integration micro element with good output.Therefore, another aspect of the present invention, a kind of device manufacturing method (that is, a kind of comprise that of utilizing in first to the 5th exposure sources is the device manufacturing method of the process of pattern transfer to the photosensitive object) of the present invention's of use first to the 5th exposure sources is provided.
In addition, when making exposure sources, regulate projection optical system, can regulate the imaging characteristic of projection optical system with good degree of accuracy by after the main body that projection optical system is combined to exposure sources, utilizing one of first to the 3rd imaging characteristics adjusting method.Therefore, another aspect of the present invention has been to provide a kind of method of making exposure sources, comprises a process of regulating projection optical system of utilizing in first to the 3rd imaging characteristics adjusting method
Description of drawings
Fig. 1 is the exposure sources structure diagram according to the embodiment of the invention;
Fig. 2 A～2F is a diagrammatic sketch of explaining the definition of the driving directions such as movable lens that driven when preparing database;
Fig. 3 is the skeleton view of measuring reticle;
Fig. 4 is that measuring reticle is installed near XY cross sectional view and the projection optical system sketch the optical axis under the state on the graduation pallet;
Fig. 5 is that measuring reticle is placed under the state on the graduation pallet-near Y one side end XY cross sectional view and the sketch of projection optical system;
Fig. 6 A and 6B are formed on the measured pattern on the measuring reticle and the diagrammatic sketch of reference pattern in the present embodiment;
Fig. 7 is the control algolithm process flow diagram that is used for the master controller CPU of the measurement of imaging characteristic and demonstration (simulation);
Fig. 8 is the process flow diagram of handling in the subroutine 126 shown in Figure 7;
Fig. 9 A is diminished image (latent image) diagrammatic sketch that is formed on the measured pattern on the wafer resist layer with predetermined space, and Fig. 9 B is the position relation between the latent image of the latent image of the measured pattern shown in Fig. 9 A and reference pattern;
Figure 10 is the sectional view of portable wavefront aberration measuring unit; With
Figure 11 A and 11B are illustrated respectively in optical system not to be had aberration and light beam from the microlens array outgoing is arranged under the state of aberration.
Carry out optimal mode of the present invention
Below with reference to Fig. 1～9B embodiments of the invention are described.
Fig. 1 represents the one-piece construction according to the exposure sources 10 of the embodiment of the invention.Exposure sources 10 be one based on the reduced projection exposure sources that repeats step-by-step method or so-called ledex, utilize pulsed laser light source as exposure light source (below be called " light source ").
Exposure sources 10 comprises: an illuminator of being made up of light source 16 and lamp optical system 12; A graduation pallet RST who is used as mask platform, the fixing graticule R of this mask platform, the illumination for exposure light EL illumination that graduation pallet RST sends with illuminator as energy beam as mask; A projection optical system PL projects to the illumination for exposure light EL that sends from graticule R on the wafer W (on the image plane) as substrate; A wafer station WST who is used as chip bench settles on it to be used for fixing the z of wafer W to tilting table 58; With a control system that is used to control above-mentioned parts.
Light source 16 is pulsed ultraviolet light sources of sending the pulsed light of vacuum ultraviolet wave band, as F 2Laser instrument (wavelength is 157nm) or ArF laser instrument (wavelength is 193nm).Perhaps, light source 16 can be a light source that sends the pulsed light of extreme ultraviolet or ultraviolet band, as KrF excimer laser (wavelength of 248nm).
In fact, light source 16 is arranged in the service space of a low cleaning degree, and this chamber is different with the clean room of arranging a cavity 11.In cavity 11, adorning an exposure sources main body, this main body is made up of the parts such as various elements, graduation pallet RST, projection optical system PL and wafer station WST such as lamp optical system 12, and light source 16 is attached to cavity 11 through printing opacity optical system (not shown).The printing opacity optical system comprises the part of at least one optical axis that is known as beam coordination unit adjusting optical system as this system.The internal controller of equipment is according to the ON/OFF of the control information TS control laser beam LB output that comes autonomous controller 50, laser beam LB energy, oscillation frequency (repetition frequency), spectrum half-band width (width of wavelength coverage) and the light source 16 etc. of each pulse.
Lamp optical system 12 comprises: the even lamp optical system 20 of beam-shaping comprises such as parts such as lens pillar, beam expander (not shown), optical integrators (homogenizer) 22; An illuminator aperture stop plate 24; One first relay lens 28A; One second relay lens 28B, a blind graticule 30; A mirror M that is used for deflection optical path; A convergent lens 32 etc.As optical integrator, can use fly lens, bar-shaped integrator (reflection-type integrator) or diffractive-optical element.In this embodiment because fly lens is used as optical integrator 22, so following it be known as fly lens 22.
The light-transmissive window 17 of the even lamp optical system 20 of beam-shaping through being arranged on the cavity 11 is attached to printing opacity optical system (not shown).It utilizes parts such as lens pillar and beam expander to send and enter into through light-transmissive window 17 the xsect shaping of the laser beam LB of the even lamp optical system 20 of beam-shaping from light source 16.Fly lens 22 in the even lamp optical system of beam-shaping 20 outgoing sides forms an area source (secondary souce), this area source is made up of a large amount of pointolites that are distributed on the focal plane, outgoing side, so that overlap with the pupil plane of lamp optical system 12 basically, the xsect of laser beam is by shaping, thereby with uniform illumination profile graticule R thrown light on.Be called " illumination light EL " below the laser beam of sending from secondary souce.
Near the focal plane of fly lens 22 outgoing sides, the illuminator aperture stop plate 24 that is made of discoid element is set.And on illuminator aperture stop plate 24, less aperture diaphragm (little σ diaphragm), a ring aperture diaphragm (annulus diaphragm) and improved aperture diaphragm that is used for improving illumination of forming by a plurality of holes of concentric setting (Fig. 1 only shows two class aperture diaphragms) that is used to form the illumination ring of light of correlation factor σ of arranging an aperture diaphragm that constitutes by circular hole (conventional diaphragm), constitute by a small sircle hole with angle same basically for example.Illuminator aperture stop plate 24 structures also are arranged to be rotated as motor by driver element 40, by master controller 50 controls, and one of them aperture diaphragm is selected to be arranged to be on the light path of illumination light EL, make that the shape of illuminated area is not limited to annulus, small circle ring, large circle, four eyes etc. in the kohler's illumination of describing later.
Replace aperture stop plate 24 or combination with it, can arrange between light source 16 and optical integrator 22 that an optical unit, this optical unit comprise a plurality of diffractive-optical elements at least, the movable prism (circular cone prism, polygon prism etc.) that moves along the optical axis of lamp optical system and at least one in the varifocal optical system.And the illumination light intensity distributions when being fly lens on the plane of incidence by changing optical integrator 22, or change illumination light incident angle distribution range on the plane of incidence when optical integrator 22 is inside surface reflection-type integrator, the light quantity distribution of illumination light on the lamp optical system pupil plane (size of secondary souce and shape), in other words, the optical loss due to being changed by the condition of illumination graticule R preferably is inhibited.In addition, in the present embodiment, a plurality of light source images (virtual image) that formed by inside surface reflection-type integrator also are known as secondary souce.
On the light path of the illumination light EL that sends from illuminator aperture stop plate 24, arrange the relay optical system that a graticule 30 that be made up of the first relay lens 28A and the second relay lens 28B, blind is provided with therebetween.Blind graticule 30 is arranged on the plane with the pattern plane conjugation of graticule R, and forms a rectangular aperture that rectangular illumination district IAR is set on graticule R.In the case, a shifting board with variable openings shape is used as blind graticule 30, and according to the baffle plate configuration information, be also referred to as mask information, by master controller 50 opening is set.
On the light path of illumination light EL after the second relay lens 28B that forms relay optical system, deflection mirror M is set, is used for the illumination light EL by the second relay lens 28B is reflected to graticule R.And on the illumination light EL light path after mirror M, convergent lens 32 is set.
In said structure, the plane of incidence of fly lens 22 is set, the plane of blind graticule 30 is set on it and the pattern plane of graticule R is set to optical conjugate, and the Fourier transform face (emergent pupil face) that is formed on surface of light source (pupil plane of lamp optical system) and projection optical system PL on the focal plane, fly lens 22 outgoing side also is set to optical conjugate, thereby forms a kohler's illumination system.
Below the concise and to the point operation of describing lamp optical system 12 with said structure.The pulse laser beam LB that sends from light source 16 enters the even lamp optical system 20 of beam-shaping to the xsect shaping of light beam.Light beam enters fly lens 22 then, and forms secondary souce on the focal plane, outgoing side of fly lens 22.
As the illumination light EL that sends from secondary souce during by aperture diaphragm on the illuminator aperture stop plate 24, it passes the rectangular aperture of blind graticule 30 through the first relay lens 28A, and pass the second relay lens 28B again, mirror M deflection vertically downward afterwards is reflected.Then, pass after the convergent lens 32, illumination light EL throws light on uniform illumination to the rectangular illumination district TAR that is fixed on the graticule R on the graduation pallet RST.
On graduation pallet RST, graticule R is by arrangements and fixing such as electrostatic chucks (or vacuum cup).The structure of graduation pallet RST makes it can drive (and rotation) by a drive system (not shown) subtly on surface level (XY plane).In addition, graduation pallet RST can (the approximately length of graticule R) be moved in the predetermined stroke range of Y direction.The position of graduation pallet RST is by position sensor, as the resolution measurement of graticule laser interferometer with for example 0.5～1nm, and measurement result is offered master controller 50.
The material that is used for graticule R is dependent on the light source of use.More particularly, when ArF excimer laser or KrF excimer laser are used as light source, can use synthetic quartz, crystal of fluoride such as fluorite, fluorine-doped quartz etc., and when the F2 laser instrument is used as light source, the material require that is used as graticule R is a crystal of fluoride, as fluorite, fluorine-doped quartz etc.
Projection optical system PL for example is a two heart reduction system far away, and the projection magnification ratio of projection optical system PL for example is 1/4,1/5 or 1/6.Therefore, when the surround IAR on the graticule R throws light in the above described manner with illumination light EL, the logo image that is formed on the graticule R dwindles with above-mentioned projection magnification ratio through projection optical system PL, and is projected and is transferred on the rectangular area IA on the wafer W that is coated with resist (photochromics) (usually with take to distinguish overlap).
Projection optical system PL be one by a plurality of refraction optical elements (lens) 13 as about 10～20 dioptric systems of forming, as shown in Figure 2.About forming a plurality of lens 13 of projection optical system PL, a plurality of lens 13 of object plane one side (graticule R one side) 1, 13 2, 13 4(for simplicity, four lens devices being arranged herein) is movable lens, and they can be by 48 external drives of imaging characteristic correcting controller.The lens carrier (not shown) is fixed lens 13 respectively 1, 13 2, 13 4, three some places on gravity direction support and these lens carriers are by drive unit such as piezoelectric element (not shown).And impose on the voltage of drive unit, lens 13 by independent regulation 1, 13 2, 13 4Can move in Z-direction, and on respect to the direction of XY plane inclination (promptly around the direction that X-axis is rotated and the direction of rotating), be driven (inclination) around Y-axis as projection optical system PL optical axis direction.In addition, lens carrier (not shown) fixed lens 13 3, and around this lens carrier, with angle same basically, as 90 ° drive unit is set, as piezoelectric element.Backward driving device is set in pairs, and regulates and to be applied to every pair voltage, make lens 13 3Can move at the XY planar.In this embodiment, lens 13 1, 13 2, 13 3, 13 4Each constitutes a particular optical element that is used to regulate.Particular optical element is not limited to lens 13 1, 13 2, 13 3, 13 4, can comprise near the pupil plane of projection optical system PL or the lens of image plane setting, or be used to proofread and correct the aberration correction plate (optical sheet) of projection optical system PL aberration that especially non-rotating symmetry is set up.In addition, the degree of freedom of particular optical element (movably direction number) is not limited to two or three, can be one or four and more.
In addition, an aperture diaphragm 15 is set, and the numerical aperture of aperture diaphragm 15 (N.A) can change continuously in a preset range near the pupil plane of projection optical system PL.As aperture diaphragm 15, for example use so-called iris aperture diaphragm, and master controller 50 control aperture diaphragms 15.
When ArF excimer laser or KrF quasi-molecule during as illumination light EL, the material that is used in each lens element among the projection optical system PL can be a synthetic quartz, still, and when using F 2During laser instrument, the lens material of all uses must be a crystal of fluoride, as the aforementioned fluorite or fluorine-doped quartz.
The wafer station WST that constitutes can freely be driven by wafer station drive part 56 on the XY two dimensional surface.And wafer W is fixed on by electrostatic chuck, vacuum chuck etc. by the chip support (not shown) and is placed in Z on the wafer station WST on tilting table 58.Z to tilting table 58 regulate wafer W Z to position (focal position) and wafer W with respect to the pitch angle on XY plane.In addition, be fixed on the flexible mirror 52W of Z on tilting table 58 by one, measure the X of wafer station WST and Y position and rotation (comprise deflection, pitching and wave) with the wafer laser interferometer 54W of an outer setting.The measured value of wafer laser interferometer 54W offers master controller 50.
In addition, be formed with reference marker on it and be fixed on Z to tilting table 58, make surface surperficial contour with wafer W basically of reference marker plate FM as the reference marker plate FM of the mark that is used for base measurement and uses.
In the exposure sources 10 of present embodiment, though be removed in the accompanying drawing, on graticule R, be provided with a pair of graticule calibration microscope, each microscope is made of TTR (running through graticule) collimating optical system.About this system, exposure wavelength is used for observing graticule mark 2 on the graticule R and the reference marker on the reference marker plate simultaneously by projection optical system PL.As such graticule calibration microscope, use to have to be similar to Japanese patent application JP07-176468 and corresponding U.S. Patent application US5 the microscope of disclosed structure in 646,413.As long as the state's laws of application designated state of this international application and selected state allow, above-mentionedly be disclosed in this and draw and be reference.
In addition in the present embodiment, though be removed in the accompanying drawing, with a focus detection sensor measurement that is made of many focal positions detection system, its details is for example in Japanese patent application JP06-283403 and corresponding U.S. Pat 4 in the position of Z direction for wafer W, open in 448,332.The output of focus sensor offers master controller 50, and this controller carries out so-called focus leveling by control Z to tilting table 58.As long as the state's laws of application designated state of this international application and selected state allow, above-mentionedly be disclosed in this and draw and be reference.
In addition, on the side of projection optical system PL, be provided with one based on calibration system (not shown) from method of principal axes.As this system, for example use the microscope of FIA (field pattern resembles calibration) system based on image processing method.In this system, for example the broadband detecting light beam that resist on the wafer is not exposed shines on the target indicia, pick up by a pick device (as CCD) and be formed on the lip-deep target indicia image of photodetection, and be output into picture signals by reflected light from target indicia and indication image.And, can record on the XY two-dimensional directional position of reference marker and the collimating marks on the wafer on the reference marker plate according to the output of calibration system.
In control system shown in Figure 1, master controller 50 is played the part of important role.Master controller 50 is made up of the workstation (or microcomputer) that the so-called CPU of comprising (central processing unit), ROM (ROM (read-only memory)), RAM (random access memory) etc. form, and control integrated operation, taking moving one's steps and the time shutter between the district as wafer station WST, making and suitably carry out exposing operation.
In addition, in the present embodiment, the storage unit of for example forming 42 by hard disk, comprise keyboard and indicator such as mouse input block 45, be attached to master controller 50 such as the display unit 44 of CRT monitor or LCD and as driver element 46 outsides of an information recording carrier such as CD-ROM, DVD-ROM, MO or FD.In the information recording carrier in being arranged at driver element 46 (following), store a converse routine (first program), second program, the 3rd program and the data relevant with second program for being described as CD-ROM for simplicity.In the case, first program is one and is used for the position deviation of utilizing measuring reticle RT described later to record is converted to each the converse routine of coefficient of Zelnick polynomial expression, second program is one and is used for according to each the program of coefficient calculations imaging characteristic regulated quantity of the Zelnick polynomial expression that obtains, and the 3rd program is a program that is used for each coefficient of the Zelnick polynomial expression that obtains is converted to each imaging characteristic (desired value that comprises imaging characteristic).
Next above-mentioned database is described.Database comprises the supplemental characteristic that is used for the computational imagery characteristic, and supplemental characteristic is aforementioned movable lens 13 in the case 1, 13 2, 13 3, and 13 4Target drive amount (target regulated quantity), make and to regulate imaging characteristic according to the input of wavefront aberration measurement result.This database is made up of the data set of the imaging characteristic variable that distributes with predefined procedure that obtains as analog result.A model that is substantially equal to projection optical system PL is adopted in the simulation of carrying out, and obtains about movable lens 13 1, 13 2, 13 3, and 13 4The data that how imaging characteristic corresponding with a plurality of measurement points in the field of projection optical system PL changes during the unit's of being driven regulated quantity on each degree of freedom direction (activity direction), perhaps say so more accurately acquisition wave front data, the i.e. data that how to change about the 2nd to the 37th coefficient in the Zelnick polynomial expression.
The production process of next concise and to the point descriptive data base.At first, the design load of projection optical system PL (data of numerical aperture N.A., correlation factor σ, wavelength, each lens etc.) is inputed to the computing machine that has been mounted particular optical software that is used for simulating.Then, input about first measurement point in the field of projection optical system PL (is and measuring reticle R in this case in analog computer TThe position of any pin hole position correspondence, the back is described) data.
Next import about the data of movable lens in the unit quantity of each degree of freedom direction (activity direction).To be described in the necessary condition that is used to import before the input below.
More particularly, for movable lens 13 1, 13 2With 13 4, each movable lens 13 is the positive dirction that the Y direction tilts and directions X tilts around the direction of X-axis and Y-axis rotation, shown in the arrow of Fig. 2 A and 2B, and the unit tilt quantity is 0.1 °.In addition, when each movable lens 13 when+Z direction is mobile shown in Fig. 2 C ,+Z direction is the positive dirction that the Z direction moves, the unit amount of movement is 100 μ m.
In addition, for movable lens 133, when shown in Fig. 2 D and the 2E+when directions X moved, this direction was that directions X moves+(just) direction, and when+when the Y direction moved, this direction was that the Y direction moves+(just) direction, and the unit amount of movement is 100 μ m.
And for example, when importing at Y to the inclination movable lens forward 13 that tilts 1During the instruction of unit quantity, the departure of first wavefront of first measurement point and the desirable wavefront that is provided with in advance, for example coefficient variation of Zelnick polynomial expression each (as the 2nd to the 37th) in the field of analog computation computer projection optical system PL.Variable data is presented on the display, also is stored in the storer as parameter PARA1P1 simultaneously.
Next, when importing at X to the inclination movable lens forward 13 that tilts 1During the instruction of unit quantity, the departure of analog computation computer first measurement point, second wavefront and desirable wavefront; For example be the every coefficient variation of above-mentioned Zelnick polynomial expression, variable data is presented on the display, also is stored in the storer as parameter PARA2P1 simultaneously.
Next, when importing at Z to the mobile forward movable lens 13 that moves 1During the instruction of unit quantity, the departure of analog computation computer first measurement point the 3rd wavefront and desirable wavefront; For example be the every coefficient variation of above-mentioned Zelnick polynomial expression, variable data is presented on the display, also is stored in the storer as parameter PARA3P1 simultaneously.
Then, carry out input according to program same as described above from second measurement point to n each measurement point of measurement point, and to the Y of movable lens 131 to tilt, X to tilt and Z to the each input instruction of displacement, first, second of each measurement point of analog computation computer and the 3rd wave front data, as the every coefficient variation of above-mentioned Zelnick polynomial expression, and demonstration is also arrived storer as PARA1P2, PARA2P2, PARA3P2 to PARA1Pn, PARA2Pn, PARA3Pn with these data storing simultaneously about the data of each variable on display.
According to program same as described above to other movable lens 13 2, 13 3With 13 4Execution is about the input of each measurement point, and input only be used for each degree of freedom direction+direction driving movable lens 13 2, 13 3With 13 4The instruction of unit quantity.In response, analog computer computational activity lens 13 2, 13 3With 13 4The wave front data of each in first to n measurement point when only on each degree of freedom direction, driving unit quantity, as the every coefficient variation of above-mentioned Zelnick polynomial expression, and with parameter (PARA4P1, PARA5P1, PARA6P1, ... PARAmP1), parameter (PARA4P2, PARA5P2, PARA6P2, ... PARAmP2) ... to parameter (PARA4Pn, PARA5Pn, PARA6Pn ... PARAmPn) be stored in the storer.The data storing of matrix O that will provide following expression formula (1) then in CD-ROM as above-mentioned database.The data of matrix O are made up of column matrix (vector) PARA1P1～PARAmPn, and they are made up of the every coefficient variation of above-mentioned Zelnick polynomial expression.In this embodiment, because the movable lens that has three movable lens that can move in the three degree of freedom direction and to move two degree of freedom directions, so m=3 * 3+2 * 1=11.
O = PARA 1 P 1 PARA 2 P 1 . . . . . . PARAmP 1 PARA 1 P 2 PARA 2 P 2 . . . . . . PARAmP 2 . . . . . . . . . . . . . . . . . . PARA 1 Pn PARA 2 Pn . . . . . . PARAmPn · · · ( 1 )
Next describe the method for measuring and showing (simulation) imaging characteristic, make the operator of exposure sources 10 can understand the aberration state of projection optical system PL at an easy rate.Simulation among the embodiment requires the actual measurement data of projection optical system PL wavefront aberration, and when measuring wavefront aberration, uses measuring reticle R T(below be also referred to as " graticule R T").Therefore, measuring reticle R is at first described T
Fig. 3 represents the oblique view of measuring reticle RT.In addition, Fig. 4 represents to be placed in graticule RT on the graduation pallet RST along near the sectional view on the X-Z plane optical axis AX and the sketch of projection optical system PL.In addition, Fig. 5 represents to be placed near the cross sectional view on the X-Z plane graticule RT edge-Y one side end on the graduation pallet RST and the sketch of projection optical system PL.
Obvious from Fig. 3, the shape of measuring reticle RT is almost identical with the common graticule that has a film.Measuring reticle R TComprise a glass substrate 60, one have the rectangular plate shape shape and the center fixation of X-direction 62, one frame elements identical with the general thin frame by shape of the lens connecting piece on glass substrate 60 upper surfaces are formed in Fig. 3, be fixed on the distance piece on the glass substrate bottom surface 64 and an aperture plate 66 that is fixed on distance piece 64 lower surfaces among Fig. 3.
In lens connecting piece 62, form n circular hole 63 with matrix distribution ground I, j(I=1～p, j=1～q, p * q=n), cover the whole surface that comprises Y direction two ends.At circular hole 63 I, jWithin convergent lens 65 is set I, j, each lens is made up of the convex lens that an optical axis is in Z-direction (referring to Fig. 4).
In addition, in the space that glass substrate 60 centers on, distance piece 64, aperture plate 66, reinforcement 69 are set at interval, as shown in Figure 4 preset distance.
In addition, formation face convergent lens 65 as shown in Figure 4 on the lower surface of glass substrate 60 I, jWith measured pattern 67 I, jIn addition, in aperture plate 66, form pin hole shape opening 70 I, j, each planar survey pattern 67 I, jAs shown in Figure 4.Pin hole shape opening 70 I, jDiameter for example be about 100～150 μ m.
Referring to Fig. 3, in lens connecting piece 62, on the two ends of Y direction lens connecting piece 62, be formed centrally opening 72 in the belt-like zone respectively 1, 72 2As shown in Figure 5, form a reference pattern 74 in the bottom surface of glass substrate 60 (pattern plane) 1With opening 72 1Relatively.In addition, though be removed among the figure, one and reference pattern 74 have also been formed 1Identical reference pattern 74 2, with another opening 72 on glass substrate 60 bottom surfaces (pattern plane) 2Relatively.
In addition, as shown in Figure 3, on the X-axis of passing graticule R center, on the glass substrate outside the lens connecting piece 62 60, form a pair of graticule collimating marks RM1 and RM2 symmetrically about the center of graticule.
In the present embodiment, as measured pattern 67 I, j, adopt a grid (ranks line) pattern, as shown in Figure 6A.And corresponding with this pattern, reference pattern 74 1With 74 2Be a kind of two-dimensional grid pattern, have with Fig. 6 B in measured pattern 67 I, jThe square pattern that identical spacing distributes.As reference pattern 74 1With 74 2, can use the pattern shown in Fig. 6 A, the pattern shown in Fig. 6 B can be used as measured pattern.In addition, also can be with the pattern of other shape as measured pattern 67 I, j, in the case,, must use a kind of pattern that has preposition to concern with measured pattern as the corresponding reference pattern.That is, reference pattern need be a kind of pattern only, is the benchmark of measured pattern position deviation, regardless of shape.But, measure the imaging characteristic of projection optical system PL, the preferred a kind of whole image field of projection optical system PL or pattern of whole exposure region of covering.
Next the measurement and demonstration (simulation) method of imaging characteristic are described, make the operator of exposure sources 10 can easily understand the aberration state of projection optical system PL, in the process flow diagram of Fig. 7, the control algolithm of having represented the CPU in the master controller 50, if desired, also can be with reference to other accompanying drawing.
As a prerequisite, setting comprises the CD-ROM of first to the 3rd program and database in driver element 46, and from CD-ROM first to the 3rd program is installed in the storage unit 42.
Start the process in the flow process after the instruction that the operator begins to simulate by input block 45 input.
At first, in step 101, the 3rd program is loaded in the primary memory.Then according to the 3rd program execution in step 102～122.
At first, in step 102, when demonstration was used to the panel of the condition that is provided with on display unit 44, process proceeded to step 104 and waits for initial conditions.The operator by input block 45 input about the information of the figure main case body that will simulate (for example then, under the situation of lines-intermittent pattern, this information is spacing, live width and dutycycle) and about the information (desired value that comprises imaging characteristic of target imaging characteristic; Be also referred to as " target aberration " below the target imaging characteristic), as information about the live width exceptional value.Then, when providing the completed instruction of input, process proceeds to step 106, and the target aberration that is set to input in the step 104 in this process is set up the condition of Zelnick argument table, proceeds to step 108 then.The target aberration information of input is not limited to a kind of in the step 104.That is, can set the various imaging characteristics of projection optical system PL as the target aberration simultaneously.
In step 108, when showing the panel of input projection optical system information on display unit 44, process proceeds to step 110 and outstanding message input.The operator is after the information of input block 45 inputs about projection optical system PL, especially after the information about numerical aperture (N.A), lighting condition (as the setting of illuminator aperture diaphragm or correlation factor σ), wavelength etc., process proceeds to step 112, at there input information is stored among the RAM, and when showing input about the panel of the information of aberration on display unit 44, program proceeds to step 114 and waits information to be entered.
The operator imports the information about given aberration respectively then, or more particularly, when they are coefficient Z of 37 of the coefficient z2 to the of second of Zelnick polynomial expression 37The time, respectively identical value is input to the input screen of the aberration information of each coefficient value of Zelnick polynomial expression as 0.05 λ.
When the input of above-mentioned aberration was finished, process proceeded to step 116, there according to curve of aberration information issuing of input (as, about the Zelnick argument table of live width exceptional value).For example, the target aberration that the Z-axis of chart can be and 0.05 λ or its desired value (as the live width exceptional value, it also is the desired value of coma) are corresponding, and transverse axis can be each a coefficient of Zelnick polynomial expression.Process proceeds to step 118 then, shows the panel about confirming that above-mentioned curve is finished on display unit 44.
In next step 120, operation is ended, and indicates up to operator's input validation.After the operator indicated as the mouse input validation by input block 45, process proceeded to step 122, and the argument table that above-mentioned steps 116 is made is stored among the RAM, and judges whether all target aberrations of input in the step 104 have been made the Zelnick argument table.When being judged as of step 122 negated, process turned back to step 116 and makes the Zelnick argument table and next target aberration is made argument table.In the present embodiment, a target aberration is made an argument table, do not change numerical aperture or the lighting condition of any condition such as projection optical system PL, but for example can make a plurality of argument tables at the target aberration that changes aspect the numerical aperture of projection optical system PL or the lighting condition at least one.In addition, the figure main case body that simulate can be a plurality of, and can be to the argument table of each design producing target aberration.
When all target aberrations have been made the Zelnick argument table and step 120 imported confirm instruction after, the judgement of step 122 becomes certainly, and process proceeds to next step 124.
In step 124, judge whether sign F is " 1 ".Sign F represents whether to have imported position deviation (Δ ξ, Δ η) data.In the case, because also there are not input position deviation (Δ ξ, Δ η) data, so be judged as negatively, this process that makes proceeds to measures subroutine 126, utilizes measuring reticle R in the following manner TThe wavefront aberration of a plurality of measurement points (following is n) in the field of measurement projection optical system PL.
That is, in subroutine 126, at first in the step 202 of Fig. 8, measuring reticle RT is loaded on the graduation pallet RST by graticule loader (not shown).
In next step 204, in the output of monitoring laser interferometer 54W, move wafer station WST by wafer station drive part 56, and at a pair of graticule calibration reference mark that is formed on the reference marker plate FM of predetermined reference location positioning.The reference position is set in the case, for example makes this center overlap with the initial point of the platform coordinate system of laser interferometer 54W setting to reference marker.
In step 206, simultaneously should be to being formed on graticule collimating marks RM1 and RM2 and the corresponding graticule calibration reference mark on the measuring reticle RT with graticule calibration microscopic examination, and on the XY two dimensional surface, drive graduation pallet RST subtly by the drive system (not shown), make reference plate FM go up graticule collimating marks RM1 and the projection image of RM2 and the position deviation minimum between the graticule calibration reference mark.Finish graticule calibration by this operation, and the center that makes graticule basically with the optical axis coincidence of projection optical system PL.
In next step 208, wafer W is loaded into Z on tilting table 58 by wafer loader (not shown).The surperficial coated resist (photochromics) of wafer W.
In next step 210, the pore size of blind graticule 30 is set, make the rectangular illumination district that forms cover and comprise all convergent lenses 65 I, jMeasuring reticle R TWhole surface, remove opening 72 1, 72 2In addition, and the surround be within the X axis breadth extreme of lens connecting piece 62 in the length of X axis.In addition, simultaneously, illuminator aperture stop plate 24 is by driver element 40 rotations, for the light path of illumination light EL is provided with a predetermined aperture diaphragm, as the diaphragm of less σ.Finish the preparatory function of exposure by this operation.
In next step 212, give light source 16 control information TS, make to produce laser beam LB, and by exposing with illumination light EL irradiation graticule RT.By this operation, through pin hole shape opening 70 I, jWith projection optical system PL transfer printing simultaneously measured pattern 67 I, j, as shown in Figure 4.As a result, the measured pattern 67 of interval two dimension formation shown in Fig. 9 A on the resist layer of wafer W to be scheduled to I, jDiminished image 67 ' I, j(latent image).
In next step 214, reference pattern is covered successively and is transferred to by repeating the image that step-by-step method is formed on the measured pattern on the wafer W.Be the details of this order a～g below:
A. at first, according to the measured value of graticule laser interferometer (not shown) and the center and the reference pattern 74 of graticule 1Between the position relation of design, drive the predetermined distance of graduation pallet RST by the drive system (not shown) in Y direction, make reference pattern 74 1The center overlap with optical axis AX.
B. next, move when finishing, the aperture of blind graticule 30 is set, make the surround of illumination light EL be limited to and comprise opening 72 by the drive system (not shown) when above-mentioned 1The rectangle region that has pre-sizing on the lens mount 62 of (but not comprising any convergent lens).
C. next, mobile wafer station WST makes to form first measured pattern 67 on the wafer W 1,1Latent image 67 ' 1,1Regional center be located substantially on the optical axis AX measured value of monitoring laser interferometer 54W simultaneously.
D. then, the light source 16 that 50 pairs of master controllers are used to produce laser beam LB gives control information TS, and by to graticule R TLast radiation illumination light EL exposes.By this operation, reference pattern 74 1Cover and be transferred to and formed measured pattern 67 on the wafer W resist layer 1,1The zone of latent image (be called region S 1,1) on.As a result, first measured pattern 67 1,1Latent image 67 ' 1,1With reference pattern 74 1Latent image 74 ' 1Latent image be formed on region S with the position shown in Fig. 9 B relation 1,1
E. next, according to graticule R TLast measured pattern 67 I, jDistribute spacing and the projection magnification ratio of projection optical system PL calculate measured pattern 67 I, jThe distribute spacing p of setting.Then, move wafer station WST spacing p, make to form second measured pattern 67 in X-direction 1,2The region S of latent image 1,2The center overlap with optical axis AX basically.
F. then, give light source 16 control information TS, the feasible LB that gives off laser beam also passes through graticule R TRadiation illumination light EL and exposing.By this operation, reference pattern 74 1Cover and be transferred to the region S of wafer W 1,2On.
G. after, step-by-step operation between the repeat region and exposing operation in the manner described above, and in the region S of wafer W I, jThe latent image of last formation measured pattern and reference pattern is shown in Fig. 9 B.
When finishing exposure in this way, process proceeds to step 216, from Z unloading wafer W and it is transferred to spreader-developer (not shown, hereinafter to be referred as " C/D ") on tilting table 58, should " C/D " series connection be attached to cavity 11 by wafer loader (not shown).Process proceeds to step 218 then, input position deviation (Δ ξ, Δ η) data, and the back is chatted.
Then, in C/D, wafer W is developed, and on wafer W, be scattered in each region S of matrix according to the layout shown in Fig. 9 B I, jThe middle resist image that forms measured pattern and reference pattern.
Then, from C/D, remove the wafer W that has been developed, and measure each region S by outer overlapping measuring unit (aligning measuring unit) I, jIn aliasing error.Calculate measured pattern 67 according to this result then I, jThe resist image about reference pattern 74 1The site error (position deviation) of corresponding image.
Can consider the method for various calculating location deviations, but, preferably carry out statistical computation according to the raw data that records from improving the viewpoint of degree of accuracy.
Obtain about region S in this way I, jMeasured pattern and the XY two-dimensional position deviation (Δ ξ, Δ η) of each reference pattern.Import about region S by input block 45 by the operator then I, jThe data of position deviation (Δ ξ, Δ η).And when being judged as of step 218 was sure, process turned back to the step 128 of master routine shown in Figure 7.
By the way, about region S I, jPosition deviation (Δ ξ, Δ η) data can with the online input of the overlapping measurement in outside.And in the case, also can import in response to this, process turns back to the step 128 of master routine.
In the step 128 of master routine, first program is loaded into primary memory, process proceeds to step 130 more then,, calculates and each region S according to first program according to following principle at there I, j, in other words, with first to n wavefront (wavefront aberration) that measurement point is corresponding in the field of projection optical system PL, be each coefficient in the Zelnick polynomial expression in the case, as the 2nd coefficient Z 2～the 37 coefficient Z 37When primary memory has enough dummy sections, can in primary memory, store the 3rd program of loading in advance, but when primary memory does not have enough dummy sections, the 3rd program temporarily is unloaded to the original area of storage unit 42 from primary memory, and then first program is loaded in the primary memory.
In the present embodiment, according to above-mentioned position deviation (Δ ξ, Δ η), by calculate the wavefront that obtains projection optical system PL according to first program.Describe before this process,, earlier describe physical relation between position deviation (Δ ξ, Δ η) and the wavefront referring to Fig. 4 and Fig. 5 as a prerequisite.
As measured pattern 67 I, jThe measured pattern 67 of diffraction light in Fig. 4 that produces K, 1Shown in, pass pin hole shape opening 70 I, jLight pass the pupil plane of projection optical system PL at diverse location, particular location is according to measured pattern 67 K, 1The place of middle light outgoing.That is, pass through measured pattern 67 on the pupil plane before the wavefront of each position and the light wave K, 1The position correspondence of middle corresponding position.And when in projection optical system PL, not having aberration, suppose that this wavefront on the projection optical system PL pupil plane is desirable wavefront (being a plane in the case), as flag F at all 1Shown in.But, because there is not such projection optical system that does not have aberration, so the wavefront at pupil plane place becomes a curved surface, the wavefront F that represents as dotted line among the figure 2Therefore, according to curved surface F 2About the angle of desirable wavefront, the differential location place on wafer W forms measured pattern 67 I, jImage.
Simultaneously, as shown in Figure 5, by reference pattern 74 1(or 74 2) light of diffraction directly enters projection optical system PL, is not subjected to the restriction in pin hole shape aperture, and by projection optical system PL imaging on wafer W.But, because at reference pattern 74 1The state that is centered close to projection optical system PL optical axis under carry out reference pattern 74 1Exposure, so by reference pattern 74 1The imaging light beam that produces does not have the aberration due to the projection optical system PL basically, and making does not have position deviation ground to form image in comprising the very small region of optical axis.
Therefore, position deviation (Δ ξ, Δ η) reflects that directly wavefront arrives the gradient of desirable wavefront, and can reproduce wavefront according to this position deviation (Δ ξ, Δ η).Obvious from the above-mentioned physical relation between position deviation (Δ ξ, Δ η) and the wavefront, the principle that present embodiment is used to calculate wavefront is known Shack-Hartmann wavefront calculations principle.
Next the method for calculating wavefront according to above-mentioned position deviation is described.
As mentioned above, position deviation (Δ ξ, Δ η) is corresponding to the Grad of wavefront, and by contraposition offset difference-product branch, obtains the shape deviation of reference planes (ideal plane) (perhaps say so more accurately with) of wavefront.When wavefront (with the deviation of reference planes) is expressed as W (XY), when scale-up factor is expressed as k, there are following relationship equation (2) and (3):
Δξ = k ∂ W ∂ x · · · ( 2 )
Δη = k ∂ W ∂ y · · · ( 3 )
Because be not easy the wavefront gradients that only provides as position deviation is quadratured, so progression extended surface shape is come the match wavefront.In the case, this progression is selected an orthonormal system.The Zelnick polynomial expression is one and is suitable for the progression of expanding a face axisymmetrically about one that its component at circumferencial direction is a trigonometric series.That is, (ρ, when θ) representing, the Zelnick polynomial table is shown as R with polar coordinate system as wavefront W n m(ρ), and expand to equation (4):
W ( ρ , θ ) = Σ n A n o R n o ( ρ ) Σ n Σ m ( A n m cos mθ + B n m sin mθ ) R n m ( ρ ) · · · ( 4 )
Because known Zelnick polar coordinates polynomial expression R n m(ρ), so save description to it.Because each is a quadrature, so the coefficient A of each n m, B n mCan determine independently.Only utilize limited item that a kind of filtering is provided.
Because in fact survey differential, so need carry out match to differential coefficient as above-mentioned position deviation.In polar coordinate system (x=ρ cos θ, y=ρ sin θ), partial differential is represented by equation (5) and (6):
∂ W ∂ x = ∂ W ∂ ρ cos θ - 1 ρ ∂ W ∂ θ sin θ · · · ( 5 )
∂ W ∂ y = ∂ W ∂ ρ sin θ + 1 ρ ∂ W ∂ θ cos θ · · · ( 6 )
Because the polynomial differential of Zelnick is non-orthogonal, so need carry out match with least square method.Because each measured pattern has been provided the information (position deviation amount) of X and Y direction, so when the measured pattern numerical table is shown n (for example n is about 81～400), the observation equation number of deriving from above-mentioned equation (2)～(6) is 2n (being about 162～800).
Zelnick polynomial each corresponding to an optical aberration.In addition, the low order item corresponds essentially to Seidel aberration.Therefore, by utilizing the Zelnick polynomial expression, can obtain the wavefront aberration of projection optical system PL.
By the way, in U.S. Pat 5,978, an invention that relates to the technology of calculating wavefront aberration is disclosed in 085.In this part is open, used a kind of mask that has with measuring reticle RT same structure, and a plurality of measured patterns that pin hole and projection optical system by independent setting will be formed on the mask expose on substrate successively, and the reference pattern on the mask need not to pass convergent lens by projection optical system and pin hole exposes on substrate.Then, measure the position deviation of resist image with each resist image of reference pattern of a plurality of measured patterns, and calculate wavefront aberration by predetermined calculating.
The calculation procedure of first program is determined according to above-mentioned principle, and by carrying out first program, can obtain projection optical system PL the field in the 1st wavefront (wavefront aberration) to n measurement point, or each coefficient in the Zelnick polynomial expression in the case, as second coefficient Z 2Coefficient Z to the 37 37
(coefficient of each in the Zelnick polynomial expression is as the coefficient Z of 37 of second coefficient Z2 to the to obtain wave front data 37) afterwards, process proceeds to step 132, in this step, will identify F and be made as 1, and wave front data will be stored into the working area of RAM.
In step 134, the 3rd program is reloaded in the primary memory.In the case, in fact, after being discharged in the region of initiation of storage unit 42, first program loads the 3rd program.
At next step 136, according to the 3rd program, by under establish an equation (7), utilize the target aberration of the previous Zelnick argument table of setting up to input in each measurement point calculation procedure 104:
A=K * { Z 2* (value of table)+Z 3* (value of table)+...
+ Z 37* (value of table) } ... (7)
In the case, A is the target aberration among the projection optical system PL, as astigmatism or field curvature, or the desired value of target aberration, as the live width exceptional value, it is the desired value of coma.
K is a proportionality constant, sets according to the susceptibility of resist etc.
In the next step 138, display target aberration or the desired value in a manner described each measurement point calculated on display unit 44.And by showing that the operator can know the problem of aberrations of projection optical system PL at an easy rate.
In next step 140, judge whether to calculate all target aberrations (being provided with the aberration (imaging characteristic) of condition).Fixed if the judgment is No, then process turns back to step 136, calculates and shows next target aberration.
When having calculated all target aberrations in the above described manner, process proceeds to step 142, shows the panel whether the proof simulation continues at there on display unit 44, and process proceeds to step 144 and is parked in there then, up to having crossed preset time.
After the schedule time, carry out step 146, judged whether to import the instruction that continues simulation at there.When continuing simulation, the instruction that should continue within the predetermined time, therefore, if the answer is in the negative in step 146, then the decision that needn't continue according to simulation finishes the process of this program.
And when having imported the instruction that continues simulation within the predetermined time, process turns back to step 102, afterwards, repeats this process and judges according to next condition of regulation in the simulation.But, in the case, because be provided with sign F, thus be sure in the judgement of step 124, so process proceeds to step 136 from step 124.
That is, when measuring the wavefront aberration of projection optical system PL, need not measure wavefront aberration again and just can continue simulation.
As mentioned above, the operator only needs to import essential project according to panel successively through input block 45 in the present embodiment, and input instruction is perhaps also imported each region S in addition to measure wavefront aberration I, jIn by the data that cover the position deviation (Δ ξ, Δ η) that measuring unit records.By this operation, because the target aberration specific to the measured pattern of projection optical system PL (coma, astigmatism and the spherical aberration that comprise low order and high-order composition) calculated and is presented on the display unit 44 automatically and accurately, so can be easy to and accurately discern aberration.In addition, even, can just can accurately know this aberration by the wavefront aberration of only measuring a projection optical system PL when target aberration when being a plurality of.In the case, though various forms display target aberration is arranged, preferably with anyone form of understandable numeral result all.In the case, do not require the every coefficient of analysis Zelnick polynomial expression.
And obvious from the process flow diagram of Fig. 7, can corresponding to the exposure sources setting of present embodiment at an easy rate optimum exposure condition with the main body pattern.Promptly, when step more than promptly of repeating step 102, by importing identical main body pattern and identical target aberration (can be polytype aberration) at step 102 pair condition setting screen, and, optimum exposure condition can be set at an easy rate by importing the information that different lighting conditions, numerical aperture, wavelength etc. relate to projection optical system PL successively at step 108 pair input screen.Therefore in step 138, define the condition of the target aberration value minimum shown in the step 138.Need not to give unnecessary details, can improve software, make master controller 50 automatically define and be provided with optimum exposure condition according to this definition.This is because for example can change lighting condition respectively by the different aperture diaphragms of selecting illuminator aperture stop plate 24, so can the numerical aperture of projection optical system PL freely be arranged in the specific scope, and can be by giving the wavelength that light source 16 such control information TS change illumination light EL by the aperture diaphragm shown in Figure 1 15 of regulating projection optical system PL.
Much less, when setting up a handler file (data file of conditions of exposure is set), the operator can use the information of conditions of exposure about definition.
Next will describe the method for the imaging characteristic of regulating projection optical system PL, wherein this method is carried out by the exposure sources fabricator's of semiconductor fabrication factory etc. service technician.
As a prerequisite, the CD-ROM of the database that comprises first to the 3rd program and set up in the above described manner is set in driver element 46, and first to the 3rd program and the database relevant with second program are installed in the storage unit 42.
When by the instruction of input measurement wavefront aberrations such as service technician, master controller 50 (CPU) is with measuring reticle R TPattern transfer on wafer W, be used for measuring the wavefront aberration that a plurality of measurement points in field (being n herein) of projection optical system PL are located according to as hereinbefore program (referring to Fig. 8).In C/D, wafer W is developed then, and after wafer W is developed, according to identical layout shown in Fig. 9 B, on wafer W with each region S of matrix distribution I, jThe middle resist image that forms measured pattern and reference pattern.
Afterwards, from C/D, take out the wafer W that has been developed, and utilize outside measuring unit (aligning measuring unit) the measured zone S that covers I, jIn overlay errors.And calculate measured pattern 67 according to this result I, jResist image and reference pattern 74 1Corresponding image between site error (position deviation).
Then, pass through input block 45 with region S by service technician I, jPosition deviation (Δ ξ, Δ η) data be input in the master controller 50.By the way, region S I, jPosition deviation (Δ ξ, Δ η) data can cover measuring unit with the outside and be input to master controller 50 onlinely.
Under any circumstance, in response to above-mentioned input, the CPU of master controller 50 is loaded into first program in the primary memory, and according to position deviation (Δ ξ, Δ η), according to the first program zoning S I, jIn with the field of projection optical system PL in the 1st to n the wavefront (wavefront aberration) that measurement point is corresponding, be polynomial each the coefficient of Zelnick in the case, as polynomial the 2nd the coefficient Z of Zelnick 2Coefficient Z to the 37th 37
In the following description, interior the 1st wavefront to n measurement point (wavefront aberration) data in the field of projection optical system PL are expressed as a column matrix Q in the equation (8):
Q = P 1 P 2 . . . . . . P n · · · ( 8 )
In equation (8), the element P of matrix Q 1～P nBe each column matrix unit (vector), by polynomial the 2nd the coefficient Z of Zelnick 2Coefficient Z to the 37th 37Form.
When compute matrix Q in the manner described above, master controller 50 is stored into this value in the working area of RAM.
Next, the CPU in the master controller 50 is loaded into second program and stores the primary memory from storage unit 42, and calculates aforesaid movable lens 13 according to second program 1～13 4Regulated quantity on each degree of freedom direction.
At the 1st wavefront (wavefront aberration) data Q to n measurement point, be stored among the CD-ROM matrix O and movable lens 13 as database 1～13 4Between the adjusting vector P on each degree of freedom direction, there is following relationship formula (9):
Q＝O×P …(9)
In equation (9), P is a column matrix (vector) that m element arranged, shown in equation (10):
P = ADJ 1 ADJ 2 . . . . . . ADJm · · · ( 10 )
Therefore, from above-mentioned equation (9), know, establish an equation (11), can obtain each elements A DJ1～ADJm of P by utilizing under the least square method calculating, or perhaps movable lens 13 1～13 4Regulated quantity on each degree of freedom direction (target regulated quantity):
P＝(O T×O) -1×O T×Q (11)
In equation (11), O TBe the transformation matrix of matrix O, (O T* O) -1Be (O T* O) inverse matrix.
That is, second program is one and utilizes database to carry out the least square method Program for Calculation by above-mentioned equation (11).Therefore, CPU calculates regulated quantity ADJ1～ADJm according to second program, and represents regulated quantity again on the panel of display unit 44, and this value is stored in the storage unit 42 when reading in database among the RAM from CD-ROM successively.
Next, master controller 50 according to be stored in the storage unit 42 about movable lens 13 1～13 4Regulated quantity ADJ1～the ADJm of the drive amount on each degree of freedom direction gives command value to imaging characteristic controller calibration 48.Utilize this operation, 48 controls of imaging characteristic controller calibration are to driving movable lens 13 on each degree of freedom direction 1～13 4The voltage that applies of each drive unit, and regulate movable lens 13 basically simultaneously at least 1～13 4Position and one of posture, proofread and correct the imaging characteristic of projection optical system PL, as distortion, field curvature, coma, spherical aberration and astigmatism.As for coma, spherical aberration and astigmatism, not only can proofread and correct the low order aberration, can also proofread and correct higher order aberrations.
As mentioned above, in the present embodiment, when regulating the imaging characteristic of projection optical system P1, service technician only need be by the measurement instruction of input block 45 input wavefront aberrations, and perhaps other input is by covering the region S that measuring unit records I, jPosition deviation (Δ ξ, Δ η).By this operation, almost automatically regulate to pinpoint accuracy the imaging characteristic of projection optical system PL.
Replace above-mentioned equation (11), establish an equation down (12) can be used as second program, and this equation is one and is used to carry out the calculation procedure that least square method is calculated:
P＝(O T×G×O) -1×O T×G×Q …(12)
In equation (12), G is a following diagonal matrix that the capable and n of n row are arranged that establishes an equation, and equation (13) is:
In addition, each elements A of matrix G I, j(i=1～n) be is the diagonal matrix of element with weight parameter δ.In the case, A I, jBe one have that 36 row and 36 are listed as the represented diagonal matrix of equation (14):
Figure A20071015479300502
Therefore, diagonal matrix A I, jEach element δ J, j(j=1～36) representative and second to the 37 coefficient Z in the Zelnick polynomial expression that each measurement point records 2～Z 37Corresponding weight parameter.Therefore, for example in the time will proofreading and correct especially, only need make weight parameter value such as δ in corresponding measurement point from low order distortion that the measurement result of one or more measurement points obtains 1,1And δ 2,2Get final product greatly than remaining weight parameter.In addition, for example in the time will proofreading and correct especially from the spherical aberration that comprises high order component (0 θ component) that the measurement result of one or more measurement points obtains, the weight parameter value δ that need make only in corresponding measurement point 8,8, δ 15,15, δ 24,24, δ 35,35, δ 36,36Mean value get final product greater than the mean value of all the other weight parameter.
In the case, preferred another program of working with second program is set, and is used for specifying measurement point and imports each the panel of weight of Zelnick polynomial expression and will show successively by this program.By this configuration, service technician can be utilized input block 45 at an easy rate, when being used for the panel of specifying measurement point in demonstration the input measurement point and when being used to import the panel of weight in demonstration each weight of the input Zelnick polynomial expression corresponding with the aberration that will proofread and correct especially greater than other above-mentioned weight parameter is set.Especially at the input screen that is used to import weight, preferred above-mentioned polytype input more particularly, rather than can be imported each weight, and preferred input is divided into four groups weight as 0 θ, 1 θ, 3 θ and 4 θ.Under one situation of back, can be by desirable value of setting of each θ group input.0 θ is often referred to the coefficient (Z of the item (not comprising first and the 4th in the case) that the Zelnick polynomial expression do not comprise sin or cos 9, Z 16, Z 25, Z 36And Z 37); 1 θ is often referred to the coefficient (Z of the item (not comprising second and the 3rd in the case) that has sin θ or cos θ 7, Z 8, Z 14, Z 15, Z 23, Z 24, Z 34And Z 35); 2 θ are often referred to the coefficient (Z of the item that has sin2 θ or cos2 θ 5, Z 6, Z 12, Z 13, Z 21, Z 22, Z 32And Z 33); 3 θ are often referred to the coefficient (Z of the item that has sin3 θ or cos3 θ 19, Z 20, Z 30And Z 31); 4 θ are often referred to the coefficient (Z of the item that has sin4 θ or cos4 θ 28And Z 29).
In the present embodiment, as previously mentioned, master controller 50 is carried out the 3rd program and first programs, makes to import essential result and input instruction successively when measuring wavefront aberration when operator waits according to the demonstration on the panel by input block 45, perhaps imports the region S that is recorded by the covering measuring unit I, jPosition deviation data the time, almost can automatically know the imaging characteristic (aberration) of the projection optical system PL that will learn.Therefore, after according to the imaging characteristic of aforementioned manner by this configuration adjustment projection optical system of use PL, service technician etc. are carried out aforementioned simulation, the feasible state that can confirm to have regulated whether according to plan imaging characteristic on display screen.When not regulating according to plan, when importing a plurality of imaging characteristics, can know and not regulate imaging characteristic according to plan as the information relevant with the target imaging characteristic, therefore, can not carry out essential measure with stopping over.
In this embodiment, except that attended operation, operator etc. can also send the imaging characteristic of instruction with adjusting projection optical system PL, even also can during normal running.After operators etc. provide foregoing predetermined instruction (comprise the initial conditions setting and about the input of the information of projection optical system), by the CPU execution of master controller 50 and the process of above-mentioned analogy, set up a similar Zelnick argument table according to mode same as described above.Then, when measuring wavefront aberration and input position deviation data, the CPU of master controller 50 calculates the target imaging characteristic in the manner described above successively.In the case, replace on display unit 44, showing the information relevant,,, utilize the least square method can computational activity lens 13 according to the second program CPU according to mode as hereinbefore perhaps with demonstration with the target imaging characteristic 1～13 4In the drive amount of each degree of freedom direction, make target aberration the best (as, be zero or minimum).This can realize by the simple remodeling of software.
Then, the CPU in the master controller 50 provides the instruction of the driving value of calculating for imaging characteristic correcting controller 48.By this operation, 48 controls of imaging characteristic correcting controller impose in each degree of freedom direction and drive movable lens 13 1～13 4The voltage of each drive unit, and regulate movable lens 13 at least 1～13 4Position or wherein one of posture, proofread and correct the imaging characteristic of projection optical system PL, as distortion, field curvature, coma, spherical aberration and astigmatism.Not only the low order aberration can be proofreaied and correct as for coma, spherical aberration and astigmatism, also higher order aberrations can be proofreaied and correct.
Exposure sources 10 for present embodiment, when making semiconductor devices, the graticule R that is used to make device is loaded into graduation pallet RST goes up, and carry out preparatory function again, calibrate as EGA (the comprehensive calibration of enhancing) as graticule calibration, so-called base measurement and wafer as graticule.
The details of above-mentioned preparatory function is for example disclosed in the U.S. Pat 5,243,195 of Japanese patent application JP04-324923 and correspondence, as graticule calibration and base measurement.In addition, details about EGA are disclosed in Japanese patent application JP61-44429 and corresponding U.S. Pat 4,780,617.As long as the state's laws of application designated state of this international application and selected state allow, above-mentionedly be disclosed in this and draw and be reference.
After preparatory function is finished, expose according to repeating step-by-step method, similar with the measurement of wavefront aberration.But, in the case, according to the result of wafer calibration and take between the district as a unit stepping carry out step-by-step operation.By the way, because the operation between exposure period and common ledex without any different, so save detailed description.
Next, the method for making exposure sources 10 is described.
When making exposure sources 10, at first will comprise the lamp optical system 12, projection optical system PL, graduation pallet system of optical element such as a plurality of lens and catoptron and dress up each unit by the wafer station set of systems that a plurality of mechanical organs are formed, simultaneously each unit is regulated, regulate as optical adjustment, mechanical adjustment and electricity, make and guarantee perfect performance in each unit.
Next, lamp optical system 12 and projection optical system PL and graduation pallet system and wafer station system assembles in the exposure sources main body, are linked pipeline again.
Then, lamp optical system 12 and projection optical system PL are carried out optical adjustment.This is because the imaging characteristic of these optical systems, especially projection optical system PL has slight variation after system assembles is in the exposure sources main body.In the present embodiment, first, second also can be used in the optical adjustment of projection optical system PL with the 3rd program and aforesaid database, carries out these programs after projection optical system PL is installed in the exposure sources main body.
As first method of optical adjustment projection optical system PL, carry out the workman who regulates operation and utilize aforementioned measuring reticle R TMeasure the wavefront aberration of projection optical system PL according to aforementioned manner.Then, by to master controller 50 input measurement results, master controller 50 is carried out according to first and second programs and is handled, and makes the imaging characteristic of as far as possible accurately regulating projection optical system PL.
Then, be in the purpose of confirming to regulate the result, utilize aforesaid measuring reticle R TRemeasure the wavefront aberration of projection optical system PL according to aforementioned manner and program.Then, by measurement result to master controller 50 input wavefront aberrations, master controller 50 is carried out according to the first and the 3rd program and is handled, and shows astigmatism, field curvature and/or the live width exceptional value corresponding with the coma of projection optical system PL after regulating on display screen.At corrected aberration of this stage, mainly be higher order aberrations, can be defined as being difficult to self-regulating aberration, therefore, if necessary, can readjust the configuration of lens etc.
Second method as optical adjustment projection optical system PL, when the workman who regulates in the fabrication phase imported foregoing regulating command (comprising the information that the initial conditions setting is relevant with projection optical system with input) etc., the CPU in the master controller 50 carried out according to the 3rd program and handles and set up similar Zelnick argument table.Then, utilize aforesaid measuring reticle R TMeasure the wavefront aberration of projection optical system PL according to aforementioned program.And by the measurement result to master controller 50 input wavefront aberrations, the CPU in the master controller 50 handles and calculates successively the target aberration according to the aforesaid first and the 3rd program.Then, will be about movable lens 13 1～13 4Command value in the drive amount of each degree of freedom direction gives imaging characteristic correcting controller 48, makes these target aberration optimizations (zero or minimum).By this operation, imaging characteristic correcting controller 48 is with the target imaging characteristic of high as far as possible precision adjusting projection optical system PL, as distortion, field curvature, coma, spherical aberration and astigmatism.
Then, for the purpose of confirm regulating the result, carry out aforesaid simulation again and on display screen, show astigmatism, field curvature, the live width exceptional value corresponding etc. with the coma of projection optical system PL etc.The aberration that also is not corrected at this moment mainly is a higher order aberrations, can be judged to be the aberration that is difficult to from normal moveout correction, therefore can readjust lens subassembly if necessary.
When in addition carrying out readjusting after can't reach perfect performance the time, may must handle or change lens again.Processing again for the optical element of simplifying projection optical system PL, can utilize the measurements such as Wavefront measuring apparatus that are specifically designed to wavefront measurement before being assembled in the exposure sources main body, to measure aforesaid wavefront aberration to projection optical system PL, and whether identification has needs to handle again according to measurement result optical element and position thereof.Then, handling again of optical element that can the executed in parallel identification and readjusting of other optical element.
In addition, the optical element of each unit of projection optical system can be changed, perhaps when projection optical system has a plurality of lens barrel, each lens barrel can be changed.In addition, when handling optical devices again, if desired, surface treatment can be become aspheric surface.In addition, when regulating projection optical system PL, can change its position (comprising the interval between other optical element) or degree of tilt simply, perhaps especially when optical element is a lens element, can changes its degree of eccentricity and maybe can rotate around optical axis AX.
Then, further carry out overall adjustment (regulating and operation nuclear school) as electricity.By these operations, can make the exposure sources 10 of present embodiment, that is, and this equipment can utilize optical characteristics obtained projection optical system PL that high precision regulates with good precision the pattern transfer of graticule R on wafer W.Be preferably in and build this exposure sources in the clean room, the temperature and the cleanliness factor of clean room all are controlled.
Obvious from description up to the present, in the present embodiment, master controller 50 constitutes a computing unit; First computing unit and second computing unit and master controller 50 and imaging characteristic correcting controller 48 constitute an imaging characteristic regulon.In addition, measuring reticle R T, cover measuring unit and master controller 50 outward and form a measuring unit that is used to measure the wavefront aberration of projection optical system PL.
As previously mentioned, according to the exposure sources of present embodiment, when measuring unit (as R TWith 50) when measuring the wavefront aberration of projection optical system PL according to operator's instruction, the Zelnick argument table of the target imaging characteristic that the aberration information that provides during according to the wavefront aberration of the projection optical system PL that has recorded and with the main body pattern exposure is corresponding, master controller 50 is calculated the target imaging characteristic of projection optical system PL.By utilizing the Zelnick argument table in the above described manner, only just can calculate the target imaging characteristic with measuring a wavefront aberration.In the case, for spherical aberration, astigmatism and coma, not only the low order aberration can be calculated in the measurement, the total aberration that comprises higher order aberrations can also be calculated.
In addition, because according to the result of calculation of target aberration (imaging characteristic), by imaging characteristic regulon (48 and 50) testing target imaging characteristic as much as possible, so the imaging characteristic of projection optical system PL is therefore adjusted according to the main body pattern.
In addition, according to the exposure sources 10 of present embodiment, obtain the particular optical element (movable lens 13 that expression is used to regulate in advance 1～13 4) adjusting and the variation of the imaging characteristic of projection optical system PL between the parameter that concerns, and this parameter as database storage in storage unit 42.And the instruction of sending during according to adjustings such as service technician, the wavefront aberration of actual measurement projection optical system PL, and again when through input block 45 input measurement data (actual measurement data), master controller 50 utilizes actual measurement data and parameter and the movable lens 13 through the wavefront aberration of input block 45 inputs 1～13 4Between relational expression (equation (11) or equation (12)) computational activity lens 13 1～13 4The target regulated quantity.Because obtain above-mentioned parameter in advance and it be stored in the storage unit 42, so when actual when recording wavefront aberration, can be by importing the actual measured value of wavefront aberration simply and calculate the movable lens 13 that is used to proofread and correct wavefront aberration at an easy rate through input block 45 1～13 4The target regulated quantity.In the case, do not need the data that are difficult to obtain,, and do not need the beam trajectory of difficulty to calculate as the design data of lens.
Then, send target regulated quantity for imaging characteristic correcting controller 48 from master controller 50, and imaging characteristic correcting controller 48 is regulated movable lens 13 according to the target regulated quantity as command value 1～13 4, the imaging characteristic of projection optical system PL is carried out simple but high-precision adjusting.
In addition, exposure sources 10 according to present embodiment, when exposing, because by imaging characteristic in the above described manner according to the main body pattern adjusted or imaging characteristic according to the measurement result of wavefront aberration obtain projection optical system PL that high precision regulates the pattern transfer of graticule R on wafer W, so can with good covering degree of accuracy meticulous pattern transfer on wafer W.
In the above-described embodiments, such situation has been described, promptly, when simulation, as keyboard various information is inputed to master controller 50 through input block 45, wherein these information comprise the information about the main body pattern, information about the target imaging characteristic, about the information of projection optical system with about the information of the aberration that will provide, and according to these information, master controller 50 makes that one that provide during with 50 pairs of main body pattern exposures of master controller and the Zelnick argument table of the target imaging characteristic that aberration information is corresponding.But, the invention is not restricted to this, that is, can be installed to a various computing machine except that master controller 50 that is used for simulating to the 3rd program, and can be to doing various hypothesis such as the information of main body pattern with about the information of projection optical system.According to these hypothesis, change condition setting successively and about the information of target aberration, about the information of projection optical system and information about the aberration that will provide in, can repeat input operation to make all kinds of Zelnick argument tables corresponding in advance with input information, and can make a database by these argument tables, this database can be stored among the CD-ROM with first and second programs.
When making the database of forming by above-mentioned all kinds of Zelnick argument tables in advance, prepare a program (for simplicity, below be called " quadruple pass preface "), this program is that of the 3rd program simplifies procedures, make CPU in the master controller 50 in response to the input of wavefront aberration measurement result with condition is set, utilize corresponding Zelnick argument table to carry out aforementioned calculating, and CPU is calculated and the display target aberration immediately.The quadruple pass preface is stored among the above-mentioned CD-ROM.
When simulation, first among CD-ROM and quadruple pass preface are installed in the storage unit 42 then, and the database replication of simultaneously the Zelnick argument table being formed is in storage unit 42.Perhaps can be only first among the CD-ROM and quadruple pass preface be installed in the storage unit 42 CD-ROM is stayed in the driver element 46.When simulating under latter event, when needing, master controller 50 is read the database of Zelnick argument table from CD-ROM.In the case, the CD-ROM that is arranged in the driver element 46 forms this driver element.This can realize by improving software.
Such situation has been described in the above-described embodiments, promptly as the imaging characteristic of projection optical system, measured a wavefront aberration, this aberration is a total aberration, and has calculated the target regulated quantity of the movable lens (particular optical element that is used to regulate) that is used to proofread and correct wavefront aberration according to measurement result.But the invention is not restricted to this.For example, the imaging characteristic of the projection optical system of being regulated can be single imaging characteristic, as coma or distortion.In the case, for example obtain the particular optical element be used to the regulate relation between the variable quantity of the unit regulated quantity of each degree of freedom direction and each imaging characteristic such as coma or distortion by simulation, and according to this result, the parameter of the relation between the adjusting of acquisition expression particular optical element and the variation of projection optical system imaging characteristic, and then utilize this parameter to make a database.Then, when by for example utilizing exposure method or spatial image mensuration to obtain the coma (or live width exceptional value), distortion etc. of projection optical system and when master controller imported this measured value and come the imaging characteristic of practical adjustments projection optical system, can utilize the relation equation (this relational expression prepares in advance) between the target regulated quantity of the imaging characteristic, parameter and the particular optical element that have obtained, decide the target regulated quantity of particular optical element by calculating similar to the above embodiments.
In addition, in the above-described embodiments, the situation of utilizing measuring reticle to measure the wavefront aberration of projection optical system PL has been described.But the invention is not restricted to this, can utilize the portable wavefront aberration measuring unit that can be attached to wafer station WST main body to be carried out the measurement of wavefront aberration.As such wavefront aberration measuring unit, can use a kind of wavefront aberration measuring unit 80 based on the Shack-Hartmann method, this device uses a microlens array in its photodetection optical system, as shown in figure 10.
Below the structure of wavefront aberration measuring unit 80 will be described briefly.As shown in figure 10, wavefront aberration measuring unit 80 comprises that its inner space has one to be L shaped xsect in the YZ plane, a photodetection optical system 84, this system is made up of a plurality of optical elements that are distributed in the shell 82 with the preposition relation, also has a photodetection part 86 that is arranged on shell 82 interior+Y sides.
Shell 82 is that the L shaped element of letter is made by its xsect in the YZ plane, be formed with a space therein, and form at its top (end of+Z direction) one when looking squarely for circular opening 82a, make the light of shell more than 82 will be directed in the inner space of shell 82.In addition, a cover plate glass 88 is set and covers opening 82a with inside from shell 82.Vapour deposition by metal such as chromium on the upper surface of cover plate glass 88 forms a round-meshed shading barrier film of the heart therein, and when measuring the wavefront aberration of projection optical system PL, this barrier film will block unwanted light and enter photodetection optical system 84.
Photodetection optical system 84 by an object lens 84a who distributes successively downwards below 88 at the cover plate glass of shell 82 inside, relay lens 84b and deflection mirror 84c and deflection mirror 84c+a collimation lens 84a and a microlens array 84e that the Y side distributes successively form.The deflection mirror 84c that is provided with has 45 ° degree of tilt, and by deflection mirror 84c, and the light path from the light that enters into object lens 84a on direction vertically downward is deflected to collimation lens 84d.Each optical element of forming photodetection optical system 84 is fixed to the inwall of shell 82 respectively by the fixture (not shown).Microlens array 84e has a plurality of little convex lens (lens element) that are scattered in the array shape on the plane perpendicular to light path.
Photodetection part 86 is made up of the parts that are similar to optical detection device such as two-dimensional CCD and circuit such as charge transfer control circuit.Optical detection device has one entered object lens 84a and from the area of all light beams of microlens array 84e outgoing even as big as receiving.The measurement data of photodetection part 86 is exported to master controller 50 through the signal wire (not shown).
Next the wavefront aberration mensuration that utilizes wavefront aberration measuring unit 80 is described.In the following description, for simplicity, think that the aberration of photodetection optical system 84 is enough little in the wavefront aberration measuring unit 80, so that can ignore.
At first, in common exposure, because wavefront aberration measuring unit 80 separates to tilting table 58 with Z, so the operator carries out wavefront aberration measuring unit 80 is attached to the operation of Z to tilting table 58 when carrying out wavefront measurement.When this links operation, wavefront aberration measuring unit 80 is fixed to the predetermined reference face surface of+Y side (in the case for) by bolt or magnet, makes wavefront aberration measuring unit 80 within the movement travel that is in wafer station WST (Z is to tilting table 58) during the wavefront measurement.
Finish after the above-mentioned binding, start in response to the instruction of operator input and measure, according to from method of principal axes, master controller 50 moves wafer station WST by wafer station drive part 56, makes wavefront measurement unit 80 be positioned under the aforesaid calibration system.Then, master controller 50 utilizes calibration system to survey to be arranged on the collimating marks (not shown) on the wavefront aberration measuring unit 80, and calculates the position coordinates of collimating marks and obtain the exact position of wavefront aberration measuring unit 80 at the measured value of this point according to result of detection and laser interferometer 54W.Then, after the position that records wavefront aberration measuring unit 80, measure wavefront aberration in the following manner, master controller 50 is played the part of important role.
At first, graticule loader of master controller 50 usefulness is loaded into a measuring reticle (not shown) (in order to distinguish with aforesaid measuring reticle RT, below being also referred to as " pin hole graticule ") that is formed with the pin hole pattern on it on graduation pallet RST.Have pin hole (this pin hole becomes the ideal point light source that produces spherical wave) on this measuring reticle, pin hole is formed on the pattern plane at a plurality of somes place in the zone consistent with surround IAR, only is used for measuring.
Be used for the pin hole graticule of this situation, for example on the surface scatter plate is set thereon, make and the wavefront of the light beam can obtain passing all numerical apertures of projection optical system PL promptly, to record the wavefront aberration of all numerical apertures that comprise projection optical system PL.
Loaded after the pin hole graticule, master controller 50 utilizes aforesaid graticule calibration microscope to survey the graticule collimating marks that is formed on the pin hole graticule, and calibrates the pin hole graticule in precalculated position according to result of detection.By this operation, make the pin hole graticule the center basically with the optical axis coincidence of projection optical system PL.
Then, master controller 50 gives light source 16 with control information TS, thereby makes light source 16 emission of lasering beam.By this operation, the illumination light EL that sends from lamp optical system 12 shines on the pin hole graticule.Then, the light beam that a plurality of pin holes send from the pin hole graticule is projected optical system PL and converges on the image plane, and forms the image of pin hole on image plane.
Next, master controller 50 moves wafer station WST by wafer station drive part 56, make the practical center of opening 82a of wavefront aberration measuring unit 80 overlap with becoming image point, wherein be formed on the pin hole graticule (below be called focus on pin hole), monitor the measured value of wafer laser interferometer 54W simultaneously at the image of this one-tenth image point place pin hole.When this operates, result of detection according to aforementioned focal position detection system, master controller 50 at the fine mobile wafer station WST of Z-direction, makes the upper surface of cover plate glass 88 of wavefront aberration measuring unit 80 overlap with the image plane of formation pin hole image by wafer station drive part 56.When wafer station WST quilt is fine mobile, if desired, can also regulate the pitch angle.By this kind mode, the opening that focuses on imaging light beam process cover plate glass 88 centers of pin hole enters photodetection optical system 84, and by the optical detection device photodetection of forming photodetection part 86.
More particularly, the spherical wave that is produced by the focusing pin hole on the pin hole graticule becomes directional light and shines on the microlens array 84e through projection optical system PL and object lens 84a, the relay lens 84b, catoptron 84c and the collimation lens 84d that form photodetection optical system 84.By this operation, the pupil plane of projection optical system PL is relayed to microlens array 84e, and separates thus again.By each lens element of microlens array 84e, each light beam is converged on the photodetection face of optical detection device then, and the image of pin hole is respectively formed on the photodetection face.
In the case, when projection optical system PL is a perfect optical system without any wavefront aberration, wavefront on the projection optical system PL pupil plane becomes desired shapes (being a plane in the case), and the result, the directional light of supposing to incide on the microlens array 84e is a plane wave with desirable wavefront.In the case, shown in Figure 11 A, form a hot spot image (below be also referred to as " hot spot ") in a position on the optical axis of each lens element of forming microlens array 84e.
But, in projection optical system PL, because have wavefront aberration usually, depart from desirable wavefront so incide the wavefront of the parallel beam of microlens array 84e, and skew is corresponding therewith, promptly this wavefront is with respect to desirable wavetilt, and the displacement of the image spaces of each hot spot on each lens element optical axis of microlens array 84e is shown in Figure 11 B.In the case, it is corresponding with the degree of tilt of wavefront that each hot spot departs from the position deviation of reference point (position on each lens element optical axis).
Then, the light (light beam of hot spot image) that incides each convergent point on the optical detection device of forming photodetection part 86 is by the optical detection device opto-electronic conversion, and by circuit photoelectric conversion signal sent to master controller 50.According to photoelectric conversion signal, master controller 50 calculates the image spaces of each hot spot, and utilizes the position data calculating location deviation (Δ ξ, Δ η) of result of calculation and known reference point again, and it is stored among the RAM.When this operated, (Xi, the measured value of Yi) locating was sent to master controller 50 to laser interferometer 54W at point.
When wavefront aberration measuring unit 80 is finished the measurement of the position deviation of hot spot image at the one-tenth image point place that focuses on the pin hole image, master controller 50 moves wafer station WST, makes the image point that becomes of essence center and next pin hole image of opening 82a of wavefront aberration measuring unit 80 overlap.When this moves when finishing, master controller 50 makes light source 16 produce laser beam as previously mentioned, and calculates the image spaces of each hot spot similarly, similarly measures successively at the one-tenth image point place of other pin hole image afterwards.
When all essential measurements are all finished, in the RAM of master controller 50, store about position deviation (Δ ξ at each pin hole image of aforementioned one-tenth image point place, Δ η) data and each become coordinate data (the laser interferometer 54W when one-tenth image point of each pin hole image is measured (Xi, measured value Yi)) of image point.
Then, master controller 50 is according to position deviation (the Δ ξ that is stored in the pin hole image one-tenth image point among the RAM, Δ η), utilize aforesaid and the similar different switching program calculating of first program wave front data (coefficient of each in the Zelnick polynomial expression), wherein, this position deviation is corresponding to the degree of tilt of wavefront on the pupil plane of projection optical system PL.The reason of statement " similar with first program " is, when using foregoing wavefront aberration measuring unit 80, usually prepare a program different, the position deviation amount of the visual one-tenth of the hot spot that records image point is converted in the Zelnick polynomial expression to the coefficient of each with first program.
Obvious from description up to the present, when utilizing wavefront aberration measuring unit 80 to measure wavefront aberrations, will not need wafer development etc., therefore can expect the shortening of Measuring Time.In addition, because do not need wafer development etc., so exposure sources 10 also has an advantage to be to carry out under wavefront aberration measuring unit 80 is attached to the state of wafer station WST so-called from measuring.Then, be similar to the process of the program of the foregoing description by execution, master controller 50 can calculate and display target aberration (imaging characteristic), and therefore can automatically carry out the adjusting of projection optical system PL imaging characteristic.
In the above-described embodiments, describe first program, second program, the 3rd program and set of databases are contained in a situation among the CD-ROM, wherein first program is utilizing measuring reticle R TThe position deviation amount that records converts in the Zelnick polynomial expression coefficient of each to, second program is according to the regulated quantity of the coefficient calculations imaging characteristic of each in the Zelnick polynomial expression of changing in first program, the 3rd program converts the coefficient of each in the Zelnick polynomial expression of changing to each aberration (index that comprises this aberration) in first program, and database moves with second program.But such software package is not forced to follow.Promptly first program, second program (and database) and the 3rd program are the programs with various objectives, and they mean all have sufficient value independently.
Especially the 3rd program, its part (corresponding to step 101～122) of making the Zelnick argument table can be used as an independent program.By the input various information, comprise information about the main body pattern, about the information of target imaging characteristic, about the information of projection optical system, about the information of the aberration of the computing machine that gives to have installed this program from input block such as keyboard, make the Zelnick argument table of target imaging characteristic.Therefore, the database of being made up of the Zelnick argument table of preparation can suitably be used in other exposure sources as previously mentioned in the above described manner.
For example, when using aforesaid wavefront aberration measuring unit, usually prepare a program that is different from first program, the imaging position deviation amount of the hot spot image that records is converted to each coefficient of Zelnick polynomial expression, and even when second program and database thereof and the 3rd program therewith during the converse routine combination, second program and database and the 3rd program also can show their ability fully.
In addition, especially second program and the 3rd program are because their purpose is very different, so needn't combine them.The former purpose is that the operation that makes service technician etc. regulate the exposure sources place under repair of projection optical system imaging characteristic and adjusting to needs is more efficient, and the latter's purpose is to carry out a kind of simulation, operator at exposure sources waits when semiconductor is made the field to the main body pattern exposure, confirms whether the target imaging characteristic of projection optical system is enough.After these differences of considering their purposes, be under the situation of identical software package at second program and database thereof and the 3rd program, two class passwords for example can be set.In this case, can provide as different information storage mediums with the 3rd program,, and have only this database can be recorded among a storage medium such as the CD-ROM as a firmware with second.
In addition, in the above-described embodiments, when regulating the imaging characteristic of projection optical system PL, first to the 3rd program is installed to storage unit 42 from CD-ROM, and storage unit 42 is arrived in database replication.But the invention is not restricted to this, as long as first to the 3rd program is installed to storage unit 42 from CD-ROM, just needn't be in storage unit 42 database replication.In the case, the CD-ROM that is arranged in the driver element constitutes this storage unit.
In the above-described embodiments, such situation has been described, that is, and by corresponding to movable lens 13 1～13 4The situation of forming database in the parameter of the unit drive amount of each degree of freedom direction.But the invention is not restricted to this, can also comprise such situation, that is, in the time can changing a part of lens of forming projection optical system PL at an easy rate, the expression imaging characteristic is corresponding to the parameter of the variation of lens thickness.In this case, best lens thickness be can be regarded as the target regulated quantity.Except that these parameters, database can also comprise that expression and graticule rotate the parameter of corresponding imaging characteristic variation.In the case, for example when graticule R rotates shown in Fig. 2 F, this rotation can be in+(just) direction, and the unit amount of spin can be 0.1 °.In the case, according to the graticule amount of spin of calculating, for example can rotate at least graduation pallet RST and wafer station WST one of them.And except that these parameters, the imaging characteristic of variable effect projection optical system and the details that can regulate also can be included in this database, and as the centre wavelength of illumination light, or graticule etc. is in the position of optical axis direction.
In addition, in the above-described embodiments, master controller 50 has been described according to the target regulated quantity of the particular optical element of calculating by second program or the situation of regulating the imaging characteristic of projection optical system PL automatically by imaging characteristic correcting controller 48 by the target aberration amount that the 3rd program is calculated.But the invention is not restricted to this, the imaging characteristic of projection optical system PL can manually be regulated by the operator or by operation.In the case, the second or the 3rd program not only can be used to regulate platform effectively, and whenever also can be used in the making platform, makes the output of the projection optical system that imaging characteristic is adjusted improve.
In the above-described embodiments, described reference pattern and be arranged on measuring reticle R with measured pattern TOn situation, but reference pattern needn't be arranged on the measuring reticle mark and (is measuring reticle R in the case of the above embodiments for measuring optical characteristics T) on.That is, reference pattern can be arranged on the different marks, and perhaps reference pattern can not be arranged on mask one side, can be arranged on substrate (wafer) side.More particularly, can use to be formed with the reference wafer of reference pattern in advance corresponding to the size of projection magnification ratio, and by on reference wafer, applying a kind of resist, be transferred to measured pattern on the resist layer and to this pattern development, again by measure can be after developing the resist image of the measured pattern of acquisition and the position deviation between the reference marker, can carry out measurement same as the previously described embodiments basically.
In addition, in the above-described embodiments, after measured pattern and reference pattern are transferred on the wafer W, according to the wavefront aberration of the measurement result calculating projection optical system PL of the resist image that obtains by wafer is developed.But the invention is not restricted to this, projection image (spatial image) or measured pattern can project on the wafer, and can utilize the spatial image measuring unit to measure projection image (spatial image), perhaps can measure the latent image of the measured pattern that is formed on the resist layer and reference pattern or pass through the image that chip etching obtains.In this case, as long as record the position deviation of measured pattern and reference position (as the projected position of the design of measured pattern), just can measure the wavefront aberration of projection optical system according to program similar to the aforementioned embodiment according to measurement result.In addition, replacement is transferred to measured pattern on the wafer, also can prepare the reference wafer that has been formed with reference pattern on it in advance, and can be transferred to reference pattern on its resist layer, and the position deviation that records or the spatial image measuring unit with a plurality of apertures corresponding to measured pattern are used to measure position deviation between aperture and the reference pattern.In addition, in the above-described embodiments, utilize the covering measuring unit to measure aforesaid position deviation, but also can use other device, as be arranged on the calibrating sensors in the exposure sources.
In addition, in the above-described embodiments, use the coefficient up to the 37th in the Zelnick polynomial expression, but also can use the 38th or higher, for example utilize the 81st, the feasible high-order composition that can calculate each aberration of projection optical system PL.That is, item or the item number that is used in the Zelnick polynomial expression can be any number.In addition, because so the aberration of projection optical system PL can in the above-described embodiments, can be regulated the optical element of projection optical system PL according to generations for certain such as lighting conditions, make the target aberration except in institute be if having time zero or minimum, can also become a predetermined value.
In addition, in the above-described embodiments, service technician is carried out the installation of aforementioned program.But, for example this program also can be installed in one and is attached in the server of host computer through the internet etc., wherein host computer is totally controlled manufacturing equipment, as exposure sources or comprise the production line of a large amount of manufacturing equipments, perhaps also can be installed in this program in the exposure sources.In the case, the operator can import pattern-information, perhaps can make exposure sources to obtain pattern-information by the two-dimension code of reading bar code or being formed with the graticule that will be transferred to the pattern on the wafer on it, make exposure sources or server can automatically carry out the making of aforementioned Zelnick argument table, decision optimum exposure condition (as the numerical aperture of lighting condition and projection optical system PL), and the imaging characteristic of adjusting projection optical system PL, need not any mediation of operator or service technician.At this automatically in the operation, for example when the measurement wavefront aberration uses aforesaid measuring reticle, the calibration system of exposure sources can be surveyed the position deviation of the latent image of the latent image of the measurement image that is formed on the wafer resist layer and reference pattern.In addition, in the above-described embodiments, operator etc. are fixed to wafer station WST to wavefront aberration measuring unit 80, but for example, also can adopt a carrier system (as the wafer loading bin) of carrying out wafer or chip support replacing, so that automatically deliver wavefront aberration measuring unit 80.
In the above-described embodiments, the situation that the present invention is applied to ledex has been described, but the invention is not restricted to this, the present invention also can suitably be applied to scanning type exposure equipment, be similar to U.S. Pat 5, disclosed in 473,410 with moved further mask and substrate, mask pattern is transferred to on-chip situation.
The purposes of exposure sources is not limited to make semiconductor devices, and the present invention also can be widely used for a kind of exposure sources and a kind of exposure sources of producing thin-film head, micromachine, DNA chip etc. of LCD pattern transfer to rectangular glass.In addition; the present invention not only can use the exposure sources of producing micro element such as semiconductor devices, also can use a kind of circuit pattern is transferred on glass plate or the silicon wafer with manufacturing and be used in the mask in light exposure sources, EUV exposure sources, X ray exposure sources, the electron beam exposure equipment etc. or the exposure sources of graticule.
In addition, the light source of the exposure sources in the foregoing description is not limited to the ultraviolet pulse light source, as F 2Laser instrument, ArF excimer laser or KrF excimer laser also can use the ultrahigh pressure mercury lamp of divergent-ray such as g line (wavelength is 436nm) or i line (wavelength is 365nm).
In addition, also can use by utilizing er-doped (or er-doped and yttrium) fiber amplifier to amplify the single wavelength laser bundle and the harmonic wave of the infrared or visible light wave range that dfb semiconductor laser instrument or fiber laser send by utilizing nonlinear optical crystal that this Wavelength conversion is obtained as ultraviolet light.In addition, the magnification of projection optical system is not limited to reduction system, the system of magnification or amplification such as also can adopt.In addition, projection optical system is not limited to dioptric system, also can use catadioptric system with reflective optical devices and refraction optical element and the reflecting system of only utilizing reflective optical devices.When catadioptric system or reflecting system during, wait the imaging characteristic of regulating projection optical system by changing as the position of the reflective optical devices (as recessed catoptron or catoptron) of aforementioned particular optical element as projection optical system PL.In addition, when F 2Laser beam, Ar 2When laser beam, EUV light etc. were used as illumination light EL, projection optical system PL can be a full reflected system that has only reflective optical devices.But, when using Ar 2When laser beam, EUV light etc., also needing graticule R is a kind of reflection-type graticule.
By the way, the following step is followed in the manufacturing of semiconductor devices: the design procedure of device function/performance; The graticule making step is made graticule according to design procedure; The wafer fabrication step is made a wafer by silicon materials; Transfer step, the exposure sources by present embodiment the pattern transfer of graticule to wafer; Device number of assembling steps (comprise and cut step, adhesion step and encapsulation step) and detection step.According to device manufacturing method, because in photoetching process, utilize the exposure sources in the foregoing description to expose, so the pattern of graticule R is transferred on the wafer W according to the projection optical system PL that the measurement result high precision of wavefront aberration is regulated according to main body pattern adjusted projection optical system PL or imaging characteristic by imaging characteristic, and therefore can complicated patterns be transferred on the wafer W with very high covering degree of accuracy.Therefore, be improved as the output of the device of end product, this makes can improve its throughput rate.
Industrial applicibility
As mentioned above, imaging characteristics measuring method of the present invention is suitable for measuring the target of projection optical system Imaging characteristic. In addition, imaging characteristics adjusting method of the present invention is suitable for regulating projection optical system Imaging characteristic. Exposure method of the present invention is suitable for forming meticulous pattern at substrate. Of the present invention Exposure sources is suitable for obtaining with imaging characteristic the projection optical system of fine adjustment and exposes. This Program and the storage medium of invention are suitable for being used in the above-mentioned exposure sources. In addition, device of the present invention The part autofrettage is suitable for use in the manufacturing micro element.

Claims (21)

  1. One kind by projection optical system the exposure method of pattern transfer to the object,
    According to the information relevant with the wavefront aberration of described projection optical system, with the corresponding Zelnick argument table of lighting condition that should be transferred to pattern on the described object and this pattern and with the equipment of regulating described projection optical system imaging characteristic in regulated quantity and the relevant data of relation of the variation of the every coefficient of Zelnick polynomial expression, regulate the imaging characteristic of described projection optical system
    By the projection optical system of regulating behind the described imaging characteristic pattern image is projected on the described object.
  2. 2. exposure method as claimed in claim 1, wherein,
    According among the feature change who moves and shine the illumination light on the described pattern of the optical element of described projection optical system at least one, regulate the imaging characteristic of described projection optical system.
  3. 3. exposure method as claimed in claim 2, wherein,
    The characteristic of described illumination light comprises wavelength.
  4. 4. exposure method as claimed in claim 2, wherein,
    For regulating described imaging characteristic, calculate the regulated quantity in the described conditioning equipment relevant with at least one side in described optical element and the described illumination light.
  5. 5. exposure method as claimed in claim 4, wherein,
    Adopt least square method to calculate described regulated quantity.
  6. 6. exposure method as claimed in claim 4, wherein,
    According to the information decision Zelnick polynomial expression every coefficient relevant, and utilize the every coefficient of described determined Zelnick polynomial expression to calculate described regulated quantity with described wavefront aberration.
  7. 7. exposure method as claimed in claim 4, wherein,
    Described Zelnick change list is paid the polynomial imaging characteristics every, that also calculate described projection optical system respectively with the polynomial a plurality of items of Zelnick of Zelnick to the aberration of setting and is obtained.
  8. 8. exposure method as claimed in claim 4, wherein,
    Detect described illumination light and measure the information relevant by described projection optical system, utilize this metrical information to calculate described regulated quantity with described wavefront aberration.
  9. 9. exposure method as claimed in claim 4, wherein,
    The lighting condition of described pattern can change, and utilizes with the described corresponding Zelnick change list of lighting condition after changing and calculates described regulated quantity.
  10. 10. exposure method as claimed in claim 4, wherein,
    When different patterns being carried out projection, utilize the Zelnick change list to calculate described regulated quantity for each described pattern with described projection optical system.
  11. 11. a device making method that comprises photoetching process,
    In described photoetching process, adopt and on the sensitization substrate, form pattern as each described exposure method in the claim 1 to 10.
  12. 12. one kind by projection optical system the exposure sources of pattern transfer to the object, comprising:
    Regulate the conditioning equipment of the imaging characteristic of described projection optical system, and
    Control device, its according to the information relevant with the wavefront aberration of described projection optical system, with the corresponding Zelnick argument table of lighting condition that should be transferred to pattern on the described object and this pattern and with described conditioning equipment in regulated quantity and the relevant data of relation of the variation of the every coefficient of Zelnick polynomial expression, control of the adjusting of described conditioning equipment to imaging characteristic
    By the projection optical system of regulating behind the described imaging characteristic pattern image is projected on the described object.
  13. 13. exposure sources as claimed in claim 12, wherein,
    Described conditioning equipment according among the feature change who moves and shine the illumination light on the described pattern of the optical element of described projection optical system at least one, is regulated the imaging characteristic of described projection optical system.
  14. 14. exposure sources as claimed in claim 13, wherein,
    The characteristic of described illumination light comprises wavelength.
  15. 15. exposure sources as claimed in claim 13, wherein,
    Described opertaing device is calculated the regulated quantity in the described conditioning equipment relevant with at least one side in described optical element and the described illumination light.
  16. 16. exposure sources as claimed in claim 15, wherein,
    Adopt least square method to calculate described regulated quantity.
  17. 17. exposure sources as claimed in claim 15, wherein,
    The every coefficient of information decision Zelnick polynomial expression according to relevant with described wavefront aberration utilizes the every coefficient of described determined Zelnick polynomial expression to calculate described regulated quantity.
  18. 18. exposure sources as claimed in claim 15, wherein,
    Described Zelnick change list is paid the polynomial imaging characteristics every, that also calculate described projection optical system respectively with the polynomial a plurality of items of Zelnick of Zelnick to the aberration of setting and is obtained.
  19. 19. exposure sources as claimed in claim 15, wherein,
    Also comprise by described projection optical system and detect the measuring equipment that described illumination light is also measured the information relevant with described wavefront aberration, utilize this metrical information to calculate described regulated quantity.
  20. 20. exposure sources as claimed in claim 15, wherein,
    The set device that also comprises the lighting condition that can change described pattern, utilize with change by described set device after the corresponding Zelnick change list of lighting condition calculate described regulated quantity.
  21. 21. exposure sources as claimed in claim 15, wherein,
    When different patterns being carried out projection, utilize the Zelnick change list to calculate described regulated quantity for each described pattern with described projection optical system.
CNA2007101547932A 2000-12-28 2001-12-27 Exposure method and apparatus and device manufacturing method Pending CN101135864A (en)

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JP2000402686 2000-12-28
JP2000402657 2000-12-28
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CN106325000A (en) * 2015-07-06 2017-01-11 上海微电子装备有限公司 Position measurement system
CN106462077A (en) * 2014-04-23 2017-02-22 利特克有限公司 Photolithography apparatus comprising projection system for control of image size
CN106767522A (en) * 2017-04-01 2017-05-31 长春理工大学 A kind of freeform optics surface detection method and device for heavy caliber depth rise
CN109917544A (en) * 2019-03-19 2019-06-21 北京遥感设备研究所 A kind of transmission-type scanning is steady as optical system
CN110031968A (en) * 2016-03-30 2019-07-19 株式会社尼康 Pattern plotter device, pattern plotter method and manufacturing method
CN114415478A (en) * 2017-01-26 2022-04-29 Asml荷兰有限公司 Method for fine tuning process model
CN114967024A (en) * 2022-06-24 2022-08-30 江西弘耀光学水晶有限公司 High-precision optical lens eccentricity adjusting structure and method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106462077A (en) * 2014-04-23 2017-02-22 利特克有限公司 Photolithography apparatus comprising projection system for control of image size
US9939734B2 (en) 2014-04-23 2018-04-10 Kulicke & Soffa Liteq B.V. Photolithography apparatus comprising projection system for control of image size
CN106462077B (en) * 2014-04-23 2019-01-25 库力&索法利特克有限公司 Lithographic equipment including the optical projection system controlled for image size
CN106325000A (en) * 2015-07-06 2017-01-11 上海微电子装备有限公司 Position measurement system
CN110031968A (en) * 2016-03-30 2019-07-19 株式会社尼康 Pattern plotter device, pattern plotter method and manufacturing method
CN110031968B (en) * 2016-03-30 2022-03-15 株式会社尼康 Pattern drawing device, pattern drawing method, and device manufacturing method
CN114415478A (en) * 2017-01-26 2022-04-29 Asml荷兰有限公司 Method for fine tuning process model
CN106767522A (en) * 2017-04-01 2017-05-31 长春理工大学 A kind of freeform optics surface detection method and device for heavy caliber depth rise
CN106767522B (en) * 2017-04-01 2023-05-19 长春理工大学 Optical free-form surface detection method and device for large caliber deep sagittal height
CN109917544A (en) * 2019-03-19 2019-06-21 北京遥感设备研究所 A kind of transmission-type scanning is steady as optical system
CN114967024A (en) * 2022-06-24 2022-08-30 江西弘耀光学水晶有限公司 High-precision optical lens eccentricity adjusting structure and method
CN114967024B (en) * 2022-06-24 2024-04-12 江西弘耀光学水晶有限公司 High-precision optical lens eccentric adjustment structure and method

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