TWI251663B - Determination of center of focus by cross-section analysis - Google Patents

Abstract

Method for determination of parameters in lithographic devices and applications by cross-section analysis of scatterometry model, including determination of center of focus in lithographic devices and applications. Control methods are provided for process control of center of focus in lithography devices utilizing cross-section analysis

Description

!251663 V. DESCRIPTION OF THE INVENTION (1) [Description of the invention The application of the printing technique in the technical application of the present invention. [Prior technology note recently published earlier technology. But this type of publishing technology. There are many aspects in the semi-conductor. One of them should be left from the mask or the light layer and then left to appear as a negative image. Types are also used in the application, source and excimer workforce methods, and are described in the technical field. The method is related to the method of determining the printing parameters in lithography by cross-sectional scattering model analysis, including in lithography. In the fabrication of photoresist etched wafers, the focus center discussion mentions some author publications and publication years, based on the 'period of publications' and may not be considered as such publications relative to the present invention. The discussion gives a more complete background, and the product does not constitute the application of lithographic techniques in earlier hair, optical, and other related industries for the purpose of patent determination. The lithographic technique is applied to integrated circuits, flat panel displays, magnetic heads, and the like on the production of semiconductor devices. In the lithography technique, a pattern network cable is transported to the anti-dye layer on the substrate by the pitch modulation light, and the image of the anti-dye agent is exposed, and the image of the exposure can be removed by etching. The method of dyeing or dyeing, > produces a three-dimensional space on the layer of the anti-dyeing agent, but is printed in addition to the photoresist etchant printing technique. In the kind of printing technology stepper used in the semiconductor industry, the most typical ones include lenses and light-emitting sources, wafer stages, wire nets, ^^n I: second-generation/injector And negative staining with the original step and repeat mode or step and scan mode, or

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Both have. The quality of the anti-staining 2-drawer pattern in the lithography and focal length etchant printing is also used in the flat two ‘1 in each unit area. Exposure determines the control of the image. The focal length is determined by &quot;two miles&apos; and is reduced by the illumination time and intensity, and is controlled by the modulation relative to the image?, /糸 phase, and the correct focus. ...the surface of the anti-staining layer of the $ focal plane. The exposure and focal length will be affected by the offset of the focal length and the impact of a printing technique is within acceptable limits. The lithographic technique of the rice noodle is used in applications that determine the step focal length device, such as a sweeper. However, even if the SEM process is very expensive, it is very slow and difficult to dye the thickness of the layer, the distribution of the substrate, and the difference in steps. Because of the difference, lithographic image patterns must be monitored to ensure image quality. Exposure and focus monitoring are particularly important in generating sub-micro. There are various methods and other similar printing techniques and #田策子microscopes <SEM> and other similar instruments. The measurement technology has a precision of up to 1 micron, and it requires a high vacuum chamber and is relatively automated. Optical microscopy can also be applied, but it does not have the equivalent of micron resolution. Other methods include the development of specific targets and test covers, which are shown in US patents 5,712,707 '5,953,128 and 6,088,113. The overlap error method shown in U.S. Patent No. 5,952,132 is another known method. However, these methods still need to be used with SEM, optical microscope or related direct enough instrument when the resolution required for the nature of the target is advanced.

Page 5 1251663 V. Description of the invention (3) There are many different scatterometers and related technologies and measuring instruments used in the micro-molecular structure depicting microelectronics and optoelectronic semiconductor materials, computer hard drives, optical discs, planed optical components and The lateral dimension of the other materials ranges from 1 micron to tens of microns. For example, the CDS200 scatterometer sold by Accent 0 ptica 1 Technologies, Inc. is a fully automated, zero-destructive critical dimension measurement and section wheel temple analysis system. , 7 0 3, 6 9 2nd. The instrument continuously analyzes critical dimensions with a fineness of up to 1 nm or less, while determining the profile analysis and performing a single layer thickness estimate. The instrument monitors the intensity of a single diffraction stage that varies with the angle of incidence of the illuminating beam. Variations in the intensity of the zero or squared reflections produced by the sample and the more south diffraction orders can be monitored in this manner, thus providing the information needed for the properties of the sample. The production process of the sample determines the nature of the object, so the resulting data can also be indirectly monitored for its smuggling. This methodology is an important chapter in the semiconductor manufacturing culture. Many methods and techniques for scatter analysis are widely taught, including those shown in U.S. Patent Nos. 4,710, 642, 5, 164,790, 5, 241,369, 5,70, 3,692, 5,867,276, 5,889,593, 5,912,741 and 6,100, 9 8 Number 5. Another technique for determining the best focal length is an optical cable specially designed for phase-shifting technology (R· Edwards, P· Ackmann, C.

Fischer, &quot;Characterization of Autofocus Uniformity and Precision on ASML Steppers using the Phase Shift Focus Monitor Reticle, M Proc, SP IE Vo 1. 3051, pp. 448-455, 1997). When an object is outside the best focal length

Page 6

V 1251663 V. INSTRUCTIONS (4) When photographed, the image printed from the optical network will become misaligned and have more lateral image displacement. These images can be analyzed using image reference metrics such as those used in cascade measurement techniques. Another technique for determining the optimum focal length is the line shortening method, or 'schni tzlometry11 &lt;C. P, Ausschnitt, Μ. E. Lagus, Seeing the forest for the trees: a new approach t〇CD control,” Pr〇 c. SPIE V〇l· 3332, pp·212-220, 1 9 9 8> This method uses a line/space array compared to the larger critical dimension (about 3 microns), the two arrays being adjacent to each other. When the structure is printed via focus and/or effective dose, the lines are shortened so that the space between them is widened, and this space can be measured as an image reference metric tool used in the overlay measurement technique. The technique for determining the optimum focal length is the r-diffraction characteristic difference method, or DSD' is shown in US Patent No. 6, 42 9, 9 3 nickname, inventor

Michael E. Littau and Christopher J. Raymond

Determination of Center of Focus by Diffraction Signature AnalySls. This technique is an experimental analysis of the diffraction characteristics of the scattering mode. When the optimum focal length is reached, the difference in diffraction characteristics between adjacent steps can be minimized. , '/ Another widely used decision to determine the best focal length technique is called the &quot;B〇ssung plot&quot; method. When using a critical dimension measurement tool such as a CD-SEM or scatterometer to measure the selected features printed under focus In addition to the i size, the resulting trend is usually parabolic. A parabola is placed on this critical dimension trend graph, and the tangent is zero, which is the best focal length. ^ ^

1251663 V. INSTRUCTIONS (5) The graph is called B 〇 s s u n g P 1 〇 t. One of the benefits of this method is that in addition to maintaining the best focus of the image, the exact critical dimensions in the process are also quantified. However, this method is not always strong in certain operating environments, making it difficult to determine the optimal focal length and automate it. In addition, when this technique is used in conjunction with a CD-SEM, the measurement results may be affected by changes in the angle of the sidewalls of the lines, resulting in non-objective results. The scatterometer and associated instruments can be used in a variety of different modes of operation. One method is to use a single known wavelength source whose angle of incidence 0 is varied in a determined continuous range. Another method is to use several laser beam sources and selectively project the beam at different incident angles of zero. Another method is to use an incident wide optical-spectral light source whose wavelength of the incident light source varies within a certain range and its incident angle is selectively maintained as a constant. There are also various known positional light elements that utilize optics and filtering, mirrors to create a range of incident orientations, and use a detector to detect the resulting diffraction direction. Alternatively, various polarization stage optical components can be used to change the polarized light between the s and p components using optics and filters. The angle of incidence can also be tuned around the target area within a fixed range Φ, or conversely to the source of radiation. Using the above-mentioned appointments, or arranging the use of 'can be obtained in addition to the scatterometer instrument, there is a refracted light reference source with a predetermined zero-order or higher refraction level, and the emitted light can be detected by a detector. The ray is taken, for example, by a light source or other radiation surrounding the illuminating source or any of its methods' or combining and combining the diffraction characteristics of the sample target. Many other methods and instruments are capable of determining characteristics. The method is to use a reflection or transmission through a refraction grating, ° other methods than the scatterometer

Page 8 1251663 V. INSTRUCTIONS (6) The instrument also includes a polarized ellipsometer and a refractometer. It is also known that non-light reference diffraction characteristics can also be obtained using other radiation sources such as X-rays.

In this field, a sample target known to the glutinous rice is utilized. One of the simplest and widely used sample targets is a refractive grating. In principle, it consists of a series of periodic lines. Generally, the line width to spacing ratio is between 1: 1 and 1: 3, but there are others. Know the ratio. For example, a refraction grating with a ratio of 1:3 has a linewidth of 1 〇 〇 nm and an interval of 300 nm, and the total pitch <line width plus spacing> is 400 nm. The line width and total spacing vary with the resolution of the printing process, so that when the printing process can use a smaller line width and total spacing, the line width and total spacing of the grating can be reduced in the same way. The diffractive technique can be applied to any possible line width and total pitch, including those that are much smaller than the average line spacing and total spacing used today. There are also known double-spaced and other multi-spaced structures, such as those shown in U.S. Patent No. 2002/0131055, issued September 2002. There are also known three-dimensional space gratings or structures as shown in U.S. Patent No. 6, 4 2 9,9 3 0. Thus the refractive structure may have more than one period, or may be composed of elements other than lines and spaces, such as holes, squares, columns or the like. In the prayer mode on the wafer, the diffracted light is usually dispersed into a known pattern. In this art, it is known to have several molds on a single wafer. Each diffractive pattern can be manufactured to a different focal length by printing methods, such as using different focal length settings or different exposure settings or doses. In addition, the focal length center can also be determined by the scattering mode and the diffraction grating. Its side

Page 9 1251663 V. INSTRUCTIONS (7) The method compares the diffraction characteristics produced by diffractive gratings of different focal lengths with a theoretical model database that produces the characteristics of diffraction gratings of critical dimensions. The actual diffraction measurements are compared to the model used to derive the critical dimension, and the resulting critical dimension values are plotted against the axis as a parabola plot. However, the B 〇 s s u n g P 1 〇 t method discussed above has significant limitations. SUMMARY OF THE INVENTION In one embodiment, the present invention provides a method for measuring printing parameters in relation to lithographic techniques. The method includes the steps of providing a substrate comprising a plurality of diffractive structures produced in a printing process, the diffractive structure comprising a plurality of spacer elements; and measuring a diffraction characteristic of the complex of at least three diffractive structures using a tool based on the radiation source Selecting a theoretical diffraction structure that provides a theoretical diffraction characteristic that is consistent with the diffraction characteristics of the measured diffraction structure; calculates a section of each selected theoretical refractive structure; and calculates the fracture A metric is determined between the faces to create an ideal parameter for this printing technique. In all of the methods of the present invention, the diffraction structure may be a single cycle, a double cycle, or a multi-cycle structure. The section can be a region, a block, or a sum of two or more theoretical diffraction structure parameters that provide theoretical diffraction characteristics. In one of the examples, the parameter is a critical dimension. In the method of the present invention, a theoretical diffraction structure conforming to the diffraction characteristics of the measurement diffraction structure is selected, the steps of which include generating a library of theoretical diffraction characteristics derived from the theoretical diffraction structure. And further determine the most reasonable theoretical diffraction structure from this database. this

1251663 V. INSTRUCTIONS (8) Metrics include plotting the calculated section into a map or determining the difference between the calculated sections. In another example, the present invention provides a method of determining the center of focus in a printing technique. The method includes the steps of providing a substrate comprising a plurality of diffraction structures produced by a printing device, the diffraction structure comprising a plurality of different known focal length settings; and measuring a diffraction characteristic of the plurality of diffraction structures at least three of the diffraction structures using a radiation source reference tool Providing a database of diffraction characteristics of a theoretical diffraction structure; determining a theoretical diffraction characteristic that best fits each measurement diffraction characteristic; calculating each theoretical diffraction structure that provides the most theoretical diffraction characteristics And the determination of a focal length center as the basis for the focal length setting, and this focal length setting has the smallest difference between the adjacent diffraction grating focal length setting sections. In this method, the change in the cross-sectional difference between the focal lengths of adjacent diffraction structures is approximately a parabola curve, and the tangential line is the smallest difference at zero. The decision of the minimum difference involves applying the data derived from the difference in the profile between adjacent focal diffraction grating focal length settings on a parabolic curve that is consistent with the minimum of the parabola. In these methods, the cross-section of the diffractive structure with different focal length settings can be plotted as an equation for the focal length function. The method used in the present invention further provides process monitoring of the focal length center required in printing techniques, the method comprising the steps of providing a substrate comprising a plurality of latent image diffraction structures produced using printing techniques, the diffraction structure of which Including different known focal length settings; measuring the diffraction characteristics of the complex number of at least three latent image diffraction structures using a radiation source reference tool; providing a database of diffraction characteristics of the theoretical diffraction structure;

Page 11 1251663 V. INSTRUCTIONS (9) The theoretical diffraction characteristics that best match the diffraction characteristics of each measurement; calculate the cross section of each theoretical diffraction structure to provide a theoretical diffraction characteristic that best fits; A focal length center is used as the basis for the focal length setting, and the focal length setting has the smallest difference between the focal length setting sections of the adjacent latent image diffraction structures; and the focal length value in the printing technique is adjusted to conform to the measured focal length center. In this method, the adjustment of the print focus setting may include a computer-based control system, or an auto-focus system, at least one of which may include a parameter relating to the difference between the sections.

In all of the foregoing methods, the radiation source reference tool includes a light source reference tool. In one example, the light source reference tool includes an incident laser beam source, an optical system that focuses the laser beam and scans through a range of incident angles, and a detection of the diffraction characteristics of the resulting measurement at the resulting measurement angle. Detector. The light source reference tool can further include an angular resolution scatterometer. In another different example, the light source reference tool includes a complex number of laser beam sources. In another example, a light source reference tool includes an incident wide spectral source, an optical system that focuses the beam and illuminates at a range of incident wavelengths, and an optical system that detects the resulting diffraction wavelength at the resulting measurement wavelength. Detector. In one example, a light source reference tool includes an incident light source, a component for varying the amplitude and phase of the S and P poles, an optical system that focuses the beam and illuminates inwardly over a range of incident positions. And a detector for detecting the resulting diffraction characteristic. In all of the foregoing methods, the step of measuring a diffraction characteristic includes

Page 12 1251663 V. Description of invention (ίο)

The position measurement by a tool source based on a broadband source is operated at a fixed angle and a variability angle of 0 or a variability angle Φ. In these methods, the step of measuring a diffraction characteristic may also include a direction measurement by a tool source based on a single wavelength radiation source, operating at a fixed angle, and a variability angle of 0 or variability. Angle Φ. The step of measuring a diffraction characteristic may also include the measurement of the orientation by a tool source based on multiple discrete wavelength sources or a tool source based on a wide spectrum source. The diffraction characteristic can be a reflection diffraction characteristic or a conductive diffraction characteristic. The diffraction characteristic may be a reflection normal diffraction characteristic or a higher normal diffraction characteristic, either positive or negative. It is a primary object of the present invention to provide a method of measuring parameters in a printing apparatus without the use of optical, SEM or other similar microscopic metric tools. Another object of the present invention is to provide a method of determining the center of focus in a printing apparatus. The method is to find the most suitable theoretical diffraction characteristics in a series of diffraction structures with different focal length values, and use this section to determine the focal length center.

Another object of the present invention is to provide a method for determining or measuring parameters such as the center of focus in a printing apparatus. This method is to use the reflective or conductive diffraction to derive the diffraction characteristics, and compare the diffraction characteristics with a theoretical model database, thereby selecting a theoretical diffraction characteristic that best matches the theory. Draw the cross section of the structure to find the most suitable diffraction characteristics.

Page 13 1251663 V. INSTRUCTIONS (11) Another object of the present invention is to measure or generate a diffraction characteristic in a measurement parameter such as a focal length, == related to a printing device. The variable true 3 y includes, but is not limited to, a reflective or conduction-oriented diffraction, or an upper, 'crossing position, variable polarization state or variable level or any higher order number. Combining 'to find zero power or reflectance Another object of the present invention is to determine the method of measuring parameters. Two of the same factors relating to the determination or the structure of the structure in the printing device; from the repeating or periodic diffraction level or any higher order, '= all 5 inclusive or refractions. Similar to the microscopic measurement tool to "learn: SEM or other parameters in the wV wp brush device. Another advantage of this service is that it can be produced by the method of printing by cattle - money agent = 7 I t The photoresist engraved focal length diffracts the structure or grating, and uses the difference between the -column to determine the focal length center, and the equation of the structural section function determined by the type. The section or its derivative edge is made into one Focal length Another advantage of the present invention is that the device for obtaining results such as the focal length center, such as the stepper conventional and known methods, is fast and inexpensive: the method and the skirting, the method and the cracking are more than the other The purpose and advantage of the mouth will be discussed in the following details and the application of the step-by-step by examining the following discussion:: = ' and accompanying the schema explanation. This month will be good for those who are good at

1251663 V. INSTRUCTIONS (12) The person in the domain presents a certain degree of superficiality or can be learned through practice. The objects and advantages of the invention may be realized and attained by the <RTIgt; [Embodiment] The present invention provides a method and apparatus for measuring printing parameters in relation to a printing apparatus, and one preferred example is the determination of the center of focus in the printing apparatus. In the development of a photoresist etched wafer process, the decision of the focal length center at a fixed dose is very important. In addition, the dose variable can be used to determine the difficulty of determining the center of focus. The lens used in the stepper has a fairly limited focal depth, so extreme precision is necessary. A lens that is properly focused will produce a sharper image of the printed photoresist etchant, and the lack of proper focus will result in the development of incomplete photoresist etchant images, as well as generally poor process results. Located at the center of the focal length, or the best focal length, improves process repeatability and stability. In moving forward to more descriptions of the invention, the following definitions need to be given. The lithographic technique refers to any device that utilizes an image, such as a reticle, to transfer a pattern to and selectively enter a substrate. This device therefore includes conventional optical printing, such as photoresist etch printing, but other printing methods are also included. Photoresist etchant printing, also known as lithography, uses optical methods to transfer circuit images from a primary image, called a reticle or optical network, to a wafer. In this process, one or more special materials, called anti-staining agents, are applied to the wafer used to fabricate the circuit. It is necessary to apply a layer of anti-staining agent, and the wafer must be processed by a method such as soft baking. Positive anti-dyeing or negative anti-dye photoresist etchant raw materials

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V. Description of invention (13) __________ Meaning. Positive anti-staining agents are usually insoluble in materials that are used as anti-staining agents, but become soluble when exposed to light. The anti-staining agent is usually used as an anti-staining developer. However, when exposed to light, it becomes insoluble. ^ Original: When the anti-staining agent is exposed to certain areas instead of other areas, the structure will be generated on the anti-dye film. In the optical printing, the exposure or the selective exposure is achieved by the imaging of a reticle #:, its selection, ., the image of the early wind, usually the 氺 氺 green on the reticle, and The transmitted image is projected on the anti-half agent soft moon, and the printing damages cited by ΓΓ include a stepper that projects a reticle to a coating. The shape of the shirt is a typical stepping from the day of reading the bamboo shoots, the day of the film, the lens and the source, the excimer laser source, the wafer A segment, the wafer E ' And an operator workstation 2:; network cable and negative anti-dyeing method, and the original step and repeat tj with positive anti-dye, or a combination of the two. , or V and scanning dies are applied to a wafer or a device that is produced by a printing device to sing two soils and amps in the operation of the present invention. . With the simplest structure or image. The periodic variation of the knot produced by this impression. This change in the reflectance index can be 2: the reflectance index is different, or it can be a chemical difference. Physically, the physics is poor. Other lithography produces::: The raw material of the refractive index by the photoresist or the lightness of the refractive index, 35 such as one with the air grid, or one different; The optical diffracted light is not the raw material of the original light. Chemicals Page 16 1251663 V. INSTRUCTIONS (14) =: 1 The wafer of the diffraction structure exposed by the etchant, for example, a crack-proof agent is still 'on',: the first gate. In this case, all the defenses: the exposure of the two i: r:: has - an ... unexposed anti-mechanism ::: r diffraction structure = please get. - A diffraction structure can be single-cycle = j or multi-cycle. The structure thus includes a series of flat diffraction gratings, but also includes a three-dimensional space two-column array=array structure in which periodic column diagrams d are displayed in both the x-direction and the gamma-direction. A square gentleman &amp; Γ 韶 韶 1U has a periodic diffraction structure in both the 1 direction and the γ direction. Figure 2", the member is not in a direction with a periodicity and consists of a parallel line of 25 diffraction diffraction structure thus including photoresist etchant 'grating, etching film stack #二ii genus grating and others in the field A known grating. A winding &amp; shot: has a line width and a ratio of between 1: 1 and 1: 3, and the ratio ^ ^ ratio is also applied. A typical ratio of 1: 3 ^.'Two-shot grating, there will be a 100nm line width and a total of 40 0ηιη, and the total spacing can be a small value, depending in part on the resolution of the printed T. A diffraction structure is used to generate a diffraction characteristic. A diffraction characteristic can be generated by any of a variety of instruments, such as a live shot!! Circular Polarizer' or a reflectometer. Any one uses radiation to 'Inch instruments are referred to herein as a source reference. 1. Two]: A visible source reference tool, such as a source reference tool, can be used, but the source can be non-visible radiation. Such as dawn

Page 17 1251663

V. Description of invention (15); Shooting =: 丨: The winding:: Sex is caused by - The astigmatism of the ray ray reflected by the ray can be obtained by - angle analysis of the angle of incidence 0 - PA 4 ~ a single Knowing that the wavelength source is utilized, its effect is diffracted: the sex can be changed by the range = as shown in Fig. 2. The knot 0 is the square of the two axes: ~ one with light intensity and angle of incidence and reflection Source:::, and the map. In the method, many laser beams have one square. Selective soil is also incident on the non-angle. In a wave+ range, your incident wide-spectrum light source is utilized, and the incident light number, such as h\, is incident. The horns are selectively maintained - a constant tiT: two kinds of incident phase with one range and one with a minimum of one using a polarized angle from (1) or (1)' Light: ;!: People know... Bu may also adjust the scope into the light circle as: ^, clothing, in the diffraction structure, or the diffraction structure relative to m, as shown in Figure 2. Using these various devices Any one or two hearts: 2 use 'or arrange for use' • It is possible and known to obtain a diffraction characteristic from the structure. Generally, the households "measure the incident light wave and at least one variability parameter, such as the human angle θ, the two fine-grained ^ incident light direction, the sweep angle 1 or other similar element clothing equation. Diffraction characteristics It can represent the zeroth power or the reflection, and it is the second time to return to the normal state. A conductive mode, 'is valued for application in generating a diffraction characteristic, such as using an X-ray source as a radiation source reference tool. In the operation of this service, a diffraction structure and its corresponding

Page 18 1251663

The output signal of the number of sexual physio-chemical characteristics can be used in the nature and rationality to generate the guess. The best way to circulate the knot can be selected by the reference index, and the characteristics can be achieved. Based on the actual characteristics of the database 'and' - and - ^ overlay and a wrap around by other methods of removing the letter, and the function of the equation in the database domain, the root 'includes

And will be based on theoretical diffraction. This theoretical capital. In the '&quot;force&quot; method' ^ before a specified variable parameter is produced, or it can be produced in the process of matching. A separate from the theoretical diffraction characteristic of the measured structure geometry. The structural parameters are used as theoretical data. The diffraction characteristics of the diffraction structure can be trimmed instead of the measured number of the method, and the internal difference of this signal is represented. Each characteristic is distinguished from one or the exact characteristics based on this composition. According to these optics, the invention (16) theoretical diffraction, the structure of the winding = 庠 can be any theoretical theory of the hidden. This database will measure the amount of diffraction. Therefore, in this case, the diffraction characteristic is calculated, and the calculation of the optimal fruit is performed, and the comparison can be determined by experiment 2, where ^. This database can be precisely ~ the index function of a database and the index is optimized for the 1 Bay method, one used to calculate a predicted value, and = the structure of the test call to the computer Descriptive data and the theoretical database database for measuring the diffraction of the diffraction characteristics of different method numbers, and the different results are inconsistent. The resulting size is qualitatively produced by a similar association via the set values. This type of method is selected in the light of the diffraction structure parameters based on the Maxwell diffraction structure. The amount of correlation between the diffraction structure model and the formation, as well as the knowledge. In which _ the theoretical model is, for example, the diffraction characteristic process, a set of values constitutes a material and geometry. 1251663

V. INSTRUCTIONS (17) The electromagnetic response between the diffractive structure and the illumination is digitally simulated to account for a predicted value of the diffraction characteristic. Any of a variety of optimal configuration algorithms can be utilized to adjust the value of the diffraction structure parameter, the process being repeated repeatedly to reduce the difference between the diffraction characteristics of the measurement and the expected diffraction characteristics. A best match value. US Patent/Application No. 1 / , 2 0 0 2 / 0 0 4 6 0 8 contains a database method for structural identification, and US patent application U s· 2 0 0 2/ 0 0 There is another method in the 3 8 1 9 6 note. Tongsong, the US issued patent application U. s. 2(10)2 / 〇 1 3 5 8 3

The number has a theoretical database method, as described in U.S. Patent Application No. U.S. 2 0 0 2/0 0 3 8 1 196. The diffraction structure parameters that can be utilized in a theoretical II database include any parameters that can be modeled, including the following factors: • The critical dimensions of the bottom and/or top of the structure. • Height and thickness, such as the thickness and height of a line, column or other structure. The total height of the area defined by the diffraction characteristics.形状 The shape of a structure, such as a rectangle, triangle, circle, or other geometric shape. /

• The radius of curvature of the bottom and/or top of a structure or area. • The period of the raster. • Line or other structure width. • Raw material parameters of the structure, including parameters for each layer. • The material of a substrate' is placed on its previous structure, such as the thickness of a film and the refractive index of the film underneath the structure.

Page 20 1251663 V. INSTRUCTIONS (18) # Various weighting values or average values, such as critical dimensions at a given location, and weighting values made by the associated effects of the structure and substrate, or similar values. In the practice of the present invention, a section having a diffraction structure having the most theoretical diffraction characteristics after comparison with the measurement of the diffraction characteristics is calculated. In the sense of the invention, the section is the sum of at least two diffraction characteristic parameters in an optimum configuration. For an example, the section is a section area, such as the sum of the critical dimension and height. In another example, the section is a section block, such as the sum of the critical dimensions, height, and shape of a structure. However, the section used herein does not have to be a shape defined in geometry; meaning that the section can be the sum of any two or more diffraction structure parameters. In one example, the section includes a critical dimension and at least one additional diffraction structure parameter. In the method used herein, "the sum of at least two diffraction structure parameters" means any mathematical operation or processing of the at least two parameters, including but not limited to mathematical operations including multiplication, and selection Optionally, at least one sub-mathematical method of operation is included. A section of the theoretical diffraction characteristic that meets or best matches the measurement of the diffraction characteristics can be calculated by any method known in the art. For an example, this may include matching measurement diffraction characteristics and discrete and existing theoretical diffraction characteristics in an existing database, such as selecting a best match value through various matching algorithms using defined limits. . In another example, the best match value may include a database interpolation method to achieve a theoretical diffraction characteristic even though the diffraction characteristic does not exist prior to interpolation. another

Page 21 1251663 Steps include the theory of average sampling, the diffraction characteristics method or technique, value. A series of words are represented, such as when a stepper door is opened, and at the same time, when the shutter is exposed, there is only one case where the optical network is born. The diffraction of the focal length of the selectable gate group 20 is determined by a series of identical doses of the group of gates 20, which can be used with a grating that uses a grating group 20, regardless of the dose. A wafer 1 and associated model to present a database-based diffraction characteristic. Therefore, any theoretical diffraction characteristics used to identify and obtain it can be utilized here to obtain a matching value for each of the molds shown in Figure 1A, as shown in Figure 1 for the portion of the wafer representative area. . The area exposed in a repeating step. In the ~step net or reticle exposure 5, the invention description (19) can also enter a diffractive characteristic or match the matching party or the best match in the presentation 'distribution' - generally In the printing equipment system, it will be composed of the grid of the gate group 20 in the illumination scanning system, 2 2 is the diffracted grating group 2 0 with the focal length but not, the diffracted light, and preferably all the diffraction Partially diffracting a mold, the mold is 15 . When a portion of the wafer is exposed to the web or reticle, only a portion of the mold mask can be selectively differentiated by the grating group 20. The same diffraction grating has a different set of known and incremental fixed doses. example. The entire exposed area of the light that will be exposed from the exposed area from the crystal range or focus will be moved to cause a series of not. It is also possible to use a grating as shown in Figure 1 C. The step of diffracting at a focal length diffracts the grating 2 2 on the slice 10 - the diffraction grating that sets the range in either of the diffracted light and the diffracted light is 'this winding is a series of selected examples of light peaches Change in group, which describes ~ shape I scale to another or both

Page 22 1251663 ------ V. Inventions (20) There will be changes. pass

And the change may be exemplified in one quantity. Diffraction line 2 5, using three diffractions to prepare a transparent and transparent one of the anti-staining layer cover and anti-staining when exposed, chemical changes in one material, for example, as an after-exposure layer The part of the group to be developed is transferred. This opening produces i worm hai J and thus promotes the norm, the grating 2 2 or the latitude space structure has a side that echoes the side of the region, due to the latent change in radiation between layers, which can be used in baking, yuan . In this case, the process area or system, the dose into a subsequent enclosure for 50 nm may be used in a diffraction pattern as shown in any other diffraction pattern. cover. Then, the mask or the above is transparent, and the latent image generated by the selection or giving of the full image is generated to have the purpose of the former anti-staining agent. The decision is also quoted as space 'or or the focal length is an analysis of the steps with a constant increment. So for example, the step of the focal length to 100 nm changes. The incremental structure of 1 m J to 2 m J is shown in the range of 1 C, and the transmission structure separated by the interval 30 includes some structures as shown in FIG. The anti-dye material is manufactured in a desired shape, size and configuration without a radiation source. The mirror or other optical system that is applied to the shape and spacing of the reticle to the other side can be inserted optically. Insert between the radiation source and the reticle. The energy that rises in the anti-staining agent becomes a change in the anti-staining agent. This represents the original image of the anti-staining agent, resulting in the diffraction characteristics mentioned in the face of the reflection value in the anti-staining layer. In the case of a wafer in which a latent image is prepared, it can be used to add a chemical reaction, or to spread the dye, and the anti-dyeing agent can be developed through chemical development. Among them, the anti-staining agent is etched according to the use of positive or negative anti-staining, and is used to select the anti-dye layer on the anti-dye layer.

Page 23 1251663 V. INSTRUCTIONS (21) Bottom materials, such as etched areas or spaces on other films. In the method and apparatus to which the present invention is applied, the diffraction structure may be exposed but not developed, or may alternatively be developed. Similarly, while the foregoing describes approximately a conventional method of creating a diffractive structure, any method can be applied, including the use of a transmissive reticle, any of a variety of sources, including electron beam illumination and the like. Radiation source.

In any printing device, including steppers or similar printing equipment, focal length is a very important parameter. The focal length and focal depth are a function of the quantum of the dose or radiation energy and are a function of the focal length or the distance from the lens to the target. The imaging results must be good at any point in the given exposure zone, thus producing a definable usable focal depth. However, factors other than dose and focal length can also affect focal length and focal depth, including astigmatism, field curvature, lens quality, orientation of the wafer stage on the X and Y axes, and the like. A typical production wafer stepper has a resolution of from about 0.15 to 1.23 micrometers, and a usable focal depth of from about 0. 40 to 1.50 micrometers.

In order to operate effectively in a stepper used in a photoresist process, such as a photoresist etch exposure step in a wafer fabrication process, the decision of the focal length center at a fixed dose is very important. The variable of the dose multiplies the difficulty in determining the center of the focal length. Lenses used in steppers and other printing equipment have a very limited focal depth, so extreme precision is a must. The lens under focus will produce a clear printed photoresist etched image, while out of focus will produce inactive photoresist etch features. Being located at the right focal length center also promotes process repeatability on a large scale. Once the focal length center is recognized and confirmed

Page 24 1251663 V. INSTRUCTIONS (22) It is determined that various differences are applied to determine optical methods, and inductive methods, such as the ability to determine the constant in the focal length. In the general case of the image in the printing device or in the fixed radiation, it is measured at the second degree to be a third degree space. For the sake of the rectangular side, the user refers to the pattern column and the experiment is more complicated. The automatic lens is applied to the lens and the compression core is applied. The operation of the scanner is repeated. The degree of spatial structure determines the shape of the four sides of the broken die. The spacing of the model is considered to be the light in the model. The distance between the lens and the center is the center of each section. The first changed diffraction fixture, the range variable has a line, column or selected data. The more complex edge and the south data theory are used to obtain the diffraction structure. Diffraction of the diffracted light. The first choice is to make a step by step. The diffraction pattern can be diffracted so that the structure can be gated or configurable. The volume of the three structures is a simple shape quadrilateral. Others make the film and the diffraction characteristic parameters. from. A reflected air between the focal system or the wafer. However, it is only in the preservation of the law, in the focus of the most frequently invented application in Jiaozuo, with the focal length or the periodic source reference, each of the focal points, such as the traditional, such as the hole case, the theoretical surface, or should be round Profile. Theory. The cross section will be matched to any constant around the winding. The decision of the system and the chip to the chip must be six hours. This diffractive special strip and spacing can be used in a variety of shapes or recursive libraries. It can also have optical species that have been processed by theory. These system methods and pressure schemes can be used. The distance is not one cycle or less. The type analysis uses the brush method to produce some characteristic packages. This is done by using a contour such as an unequal contour or a predictive flow parameter at the bottom.

Page 25 1251663 V. INSTRUCTIONS (23) Optical η and k values, so that the total optical path will be plotted via the theoretical section. The continuous focal length is from the center at the closer the difference between the focal steps. This method is set to echo the focus of the focus. This parabolic curve should be determined by the fact that the photoresist can have a minimum value and the thickness of the film below it so that the focal length is measured and the data is at the parabolic value, which can be included in the center of the statistical distance. These are measured by the reflector and used to measure the tool. This and/or single-line tangential technique can be technically or conductively radiated. The tool uses the reflection technique. The thickness of the layer is further from the center distance. In another area between the steps, there may be a focal length in the application library, or a maximum of zero. It cuts the value of the concave chemistry. The value can also be derived from the equation model of the best matching rational function to get a focal length step to the next. The theoretically optimal variable is the smallest point. The way is that the point where a parabola is zero is the upper or the flow, the concave downwards and thus the throwing of any one of the cases, the focal method, the minimum value of the area used here includes the traditional The best focal length of the focal length that should be calculated from the focal length is the inverse of the focal curve in the focal length of the focal point. "The smallest variety of calculated focal points is applied to the metrology tool. This tool has a diffraction structure. Radiation reference source, and by a detection, in other words, any one that can be used as a diffraction reference scattering can be used in this technology. These include but not limited Or the angular resolution and/or wavelength solution of the ellipsometer can be used to monitor the offset of the focal length and/or dose in the manufacturing background. In the calculated area of the monitoring diffraction characteristics,

Page 26 1251663 V. INSTRUCTIONS (24) If the calculated area deviates from a specific range, the process must be tested for the offset. In the use of these methods, it is necessary to use various filtering methods to remove factors that would adversely affect the focus analysis. One of the filtering methods is to take advantage of the compatibility between the experimental diffraction characteristics and the theoretical diffraction characteristics. Poorly configured match values will be removed from the analysis. The method of the present invention will find the primary application of the photoresist etchant processing step, with the determination of the optimum focal length being the most important part of the step. However, the method of the present invention can be applied more deeply to the process to determine the "best focus" setting for the surname film stack and the metal grating, or the "best etch" state associated with the etch process. The traditional B 〇 s s u n g P 1 ◦ t s method plots the critical dimension into a focal length-function equation to determine the optimal focal length. Also known is the method of 'adding other additional parameters, such as sidewall or thickness, to an equation of the focal length function to determine the best focal length <j. A. A 1 1 gair, DC Benoit, RR Hershey, LC Litt, B. Braymer, PP Herrera, CA Mack, JC Robinson, UK

Whitney, P. Zalicki, &quot;Implementation of spectroscopic critical dimension (SCD) for gate CD control and stepper characterization, ,f Proc SP IE, Vol. 4344, pp. 462-471, 2001>. However, these parameters often do not correspond to the parabola of the focal length. In the following discussion, the method of the present invention will provide an even higher result. Figure 5 shows an anti-staining method based on the scattering pattern measurement based on experimental data.

Page 27 1251663 ^----- The bottom end 踭 and p are shown as equations for the change of the focal length with the focal length. The bottom critical dimension is a graph of the equation as a function of the ratio of the critical dimension of the bottom end to the maximum bottom critical point visible in the focal length trend. In this Bossung pi〇ts method, the 1st flat is not a parabola, but it rises with the focal length and then reaches a figure. Figure 6 is an equation for the anti-staining sidewall and prevention measured by the scattering mode. The side wall and the anti-staining value are expressed as the ratio of the parameter to the Xitian 7 / recognition, and the ratio of the loyalty distance to the larger number. The sidewall trend is generally opposite to the bottom dimension, potential. When the sidewall trend is highest, the bottom critical dimension trend is lower. The highest sidewall value can be higher than 90 degrees. When the sidewall is reduced, the critical dimension of the bottom is increased. The anti-staining thickness is usually at a point in the middle of the focal length curve. Loss of protection is visible on both edges close to the focal length. It can be seen that the thickness of the anti-staining is about a parabola, but it will not be an accurate curve forever. The spring is especially in the grating structure of your collection, and its loss of dyeing can be minimized in the focal length of a large area. Fig. 7 is a graph showing an anti-staining section determined by the method of the present invention, or a cross-sectional area thereof, as a function of focal length. Among them, a simple elliptical quadrilateral model is used. The cross-sectional area is expressed as the ratio of the area of a section to the largest section of the focal length trend. The critical dimension of the bottom end of the anti-dyeing side, the side wall, and the thickness, alone, do not become a parabolic trend, as shown in Figures 5 and 6. However, when they are combined to form a grating cross-sectional area, a parabolic tendency is seen as shown in Fig. 7. Even when a single number of tables, such as critical dimensions or thicknesses, can be plotted as an equation of equation that changes with focal length and produces a parabolic curve, one is more consistent with _parabolic two in many cases.

Page 28 1251663 V. INSTRUCTIONS (26) A parabolic curve similar to the line can be found in the section used. In addition, the section need not be an area and thus may be the sum of one volume or more than two parameters that do not form a geometry. Thus, the section can be an area, a volume or a sum of two or more parameters. For an example, the critical dimension is chosen as one of the parameters. A wide variety of theoretical model profiles can be utilized to determine the section area. Figure 8 illustrates a basic theoretical grating structure, a simple rectangle, where W is the measured width, such as the critical dimension, and Η is the diffraction structure 80,8 0 ',8 (设置) disposed on the substrate 84. The measured height of the section is defined by the following formula:

H · W ross-Sect i on Area where H is the light thumb height and W is the grating width. More detailed theoretical models can be utilized to facilitate the accuracy of the stepper focus center decision. One such model is an unequal quadrilateral, adding a dimension of the sidewall angle, as shown in Figure 9, and applying the diffractive structures 82, 82', 82". Equations determining the section of the equilateral quadrilateral grating As follows: (2)

Cross-Sect i on Area II Η · (W-H/tanA) where Η is the height of the grating and W is the width of the bottom of the grating, and Α is the side angle of the unequal quadrilateral. Other more complex shapes can also be utilized. More complex shapes require more complex equations to represent the shape of the grating in cross-sectional area. The three-dimensional structure can also be analyzed in a similar way. For a three-dimensional structure, one of the sections is measured as a section volume. For example, a simple contact hole model assumes a perfect circle on both the X and Y axes.

Page 29 1251663 V. INSTRUCTIONS (27) The veranda, as well as the face as a bottom at the focal length, according to the scatterometer will result in these can be determined in a simple section, or with a thin soft break Is the sum of a number. The average value, the sum of the results, and the number of wafer stepper areas or volumes that exist outside the line are zero. In the Z-axis, a side wall fixed at 90 degrees can be broken. Calculated, thus obtaining a cross-sectional volume. The thickness of the underlying film and the optical properties of the material typically do not materially change the theoretical database model. However, the choice of configuration, and theoretical models, changes in the focal length of the property. It can thus be seen that the theoretical database can incorporate thin film thicknesses and optical constants in the cross section. This step is more complicated by adding a thin film of a uniform period to the cross-sectional area of the grating, and the contribution of the optical area constants η and K to the grating surface area. It can be seen that non-geometric sections can also be applied. Thus, the cross-section parameters such as the sum of the critical dimensions, and one or more additional parameters such as, for example, raw material parameters, weight or degree measurements, optical properties, curves, and the like. A similar method can be applied to the cross-sectional area or volume. The method analyzes the profile focal length metric to determine the printing equipment, such as the focal length center. The easiest way is to plot the section, such as the section, into an equation that changes with the focal length, and remove any factors and configure a parabolic curve to the resulting data. Cut a point is the center of the focal length, as shown in Figure 7. Another measure is to find the maximum cross-sectional area and the minimum cross-sectional area on the focal length (this depends on the maximum or minimum of the focal center respectively). Another step to the next decision to determine the center of focus is to analyze the rate of change of the section from a focal length step. Ideal theoretical case

Page 30 1251663 V. Inventive Note (28) —__ When the focal length is close to the center of the focal moment, the difference between the steps of the focal length will reduce the change from the step of one focal length to the step of the next focal length of the section. Face from a focal length step to a focal length step to the next ~ 隹 distance: t heart reaches the minimum. The section self-focus distance is the equation of the axis, and the change between the steps can also be plotted as a point of zero. The focal length =: is placed on the parabola. The tangential line is determined by the method of the present invention, which is generated by the method of the present invention: the best focal length position of the 描 描 描 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , / In this method, the - series is determined by the stage tilt and the field is not. In a region, such as a crystal f-two junction, the two diffraction gratings have the same series of continuity with the same focal length. The diffraction characteristics are obtained from 60 and 60, as shown in Fig. 4: The distance from the set diffraction grating 4〇, 45, 50, 55 is from the theoretical database and not. The theoretical contour model and the diffraction characteristics are determined by the face, such as the area of a section. This type of change changes. As a result, a diffractive grating is selected and the diffraction characteristics and the equation of the mode are selected. The surface, such as a cross-sectional area, is plotted as a positional consistency map. The stage tilt and field that produce a three-dimensional space are therefore not clearly different from the surface and the data (this field is, using the position of the diffraction structure in the field to make a conventional wafer stage with the position in the field), the focal length can be The center of the drawing system and the light in the astigmatism: Chu: = The tomb This equation may show the difference between the mirror and the light, or other defects that cause the center of the focal length of the cross. Similarly, the inclination of the field in the range of the ... and ~ ^ cross X and the υ axis can also be plotted, so that there is no focal point in the center of the field.

Page 31 1251663 V. Description of invention (29) should. The methods and apparatus of the present invention can be used for quality control testing, including analysis of focal length centers determined by other methods. This test can be used to resolve the scatterometer from the perspective described above, including related computer systems, or by other suitable instruments capable of making the described measurements. By applying an angular resolution scatterometer, the diffraction characteristics are divided into distinct diffraction orders at the angular position, which is specified by the following grating equation: sinei + sinen ηλ/d (3) where θι It is the incident angle of a negative number, and θη is the angular position of the η power diffraction order; I is the wavelength of the incident angle, and d is the interval or sum of the diffraction structures. It can thus be seen that for a zeroth power or a reflected diffraction stage, the angle of incidence is equal to the angular position of the reflection diffraction stage. However, in addition to reflection, other diffraction normals can be applied, as well as the appropriate angular position as determined by the above method. Similar relationships govern other methods of generating diffraction characteristics, so any method that produces diffraction characteristics, whether reflective diffraction orders or other higher diffraction orders, can be applied. For example, in a wavelength analysis instrument, the angle θί can be a constant, and the wavelength; I is a variable, and the equation is calculated in a predetermined η (9 η. The method and apparatus of the present invention can also be applied. To determine the center of focus, the center of focus can be adjusted by any suitable method, including the use of a computer-based control system, and the method of the present invention for determining whether an acceptable or optimal focal length has been determined. Dosage

Page 32 1251663 V. INSTRUCTIONS (30) Variables or other methods known in the art are to be accomplished.

The present invention can utilize an autofocus control system to further automate or automate the determination of the focal length center, wherein the data generated by the cross-sectional analysis, such as dose variables, is utilized in the control system to determine the focal length. Although the present invention has been described in detail with reference to certain preferred examples, other examples may achieve the same effect. Variations and modifications of the present invention will become apparent to those skilled in the art, and the scope of the appended claims is intended to cover such changes and modifications. All references, applications, patents, and publications cited above are hereby incorporated by reference.

Page 33 1251663 BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in the specification, are intended to illustrate one or more examples of the invention, and in principle. The purpose of these drawings is to describe one or more preferred embodiments of the invention, and not to illustrate elements of the solution. In order to limit the invention, in the drawings: Fig. 1 A to 1 C is an exploded view of a wafer having a mold comprising a diffraction grating. The figure VIII depicts the wafer pattern 'the mold of which includes the mold of the diffraction grating set on the wafer in Fig. iA. Two: Describe the single-diffractive optical thumb of the mold diffraction grating set in Fig. 1B. Fig. 2 is a schematic diagram showing various modes for obtaining the diffraction characteristics of the reflection zeroth power. Figure 3 depicts a three-dimensional diffraction structure. Figure 4 depicts a series of diffraction gratings. Figure 5 is a diagram depicting the critical dimension of the bottom end of a sample anti-staining agent as a function of focal length. Figure 6 is a diagram depicting the sidewalls of the sample anti-dye and the thickness of the anti-staining agent as a function of the focal length. Figure 7 is a diagram depicting the cross-sectional area of a sample anti-dye agent that follows the focal length. Figure 8 depicts a cross section of a rectangular diffractive structure. Figure 9 depicts a section of a non-rectangular diffraction structure. The symbol of the component says that the moon is transferred to the die.

Page 34 1251663 Schematic description

Diffraction grating group 20 diffraction grating 22 parallel line 25 conventional line 25 interval 30 diffractive light tear 40. 45. 50.55. 60 diffraction structure 8 0 · 8 0 \ 8 0,, diffraction structure 8 2 · 8 2,. 8 2π substrate 84第35页

Claims (1)

1251663 々, patent application scope 1. A measuring step consists of a complex number of complex elements by a diffraction structure; using a theoretical complex diffraction diffracted characteristic phasor relating to lithographic printing: provision and determination of a device 2 Device period or 3. Device 4. Device 5. Device characteristics 6. Device 7. Device ray as in the application of the multi-cycle as in the application in the application in the application of the reference in the application of the theory as in the application Refer to the rationality of the parametric ray of the application, which is in line with the square structure of the ideal patent norm. The patent paradigm of the patent paradigm of the patent paradigm of the patent patent norm of the patent paradigm of the patent paradigm of the parametric method, the method of placing the radiation structure generated during the printing process contains an interval A meta-based tool measures at least three diffractions to provide a theoretical diffraction characteristic of the theoretical diffraction characteristics and a measured diffraction structure for each selected diffraction structure to calculate its cross-section; A measure that takes the parameters of the printing mentioned. A base of profitability; a printing device in the brushing device, which surrounds the method described in the first item, wherein the diffraction is a single cycle of measuring a lithographic structure, and the first item around the double A test method in which the section is a test method according to the first item of a section, wherein the section of the section referred to in the first item of the section is provided by one or more parameter methods. One of the measurements described in the fifth item of the structure, wherein one parameter is one of the measurements described in the first item, one of which corresponds to the selection of the measurement structure, and is related to the yield-related lithographic area. The amount is related to the lithographic block. The sum of the quantities related to the rationale. The amount is related to the lithographic boundary size. A quantity related to the lithographic amount diffraction structure, a theoretical lithographic printing Page 36 1251663 VI. The scope of application for patents The characteristics of the radiation characteristics are derived. 8. If the application in the device is the best. 9. If you are applying for a reference in the device. 10. If you apply for differences in the parameters in the device. 11. If the reference in the application device is 12. If the application is in the device, the light source is 13. If the incident measurement of the incident laser range in the brush device is applied, the diffraction result is 14. If the angle is resolved in the application brush device One of the seven measurements described in relation to lithography further includes a decision on the neutral diffraction characteristics of the theoretical database. Method of patent range number of patents method of patent range number of methods based on the patent range parameter square beam source, angle of optical characteristics of the patent range parameter square scattering mode system detector tenth method, the library consists of The diffraction characteristic is a method for measuring the number of lithographic printings according to the method of the theoretical diffraction range of the theoretical diffraction range, wherein the measurement includes the first item of the calculated section. One such measurement relates to lithography, wherein the metric comprises determining a measurement related lithography as described in the first item between the calculated cross-sections, wherein the substrate comprises a wafer. One of the measurements described in the first item relates to lithography, in which a radiation source based tool comprises one. A measurement relating to lithographic printing according to the twelfth aspect, wherein the light source-based tool comprises a method of focusing and scanning the laser beam through one of the measurements and detecting one of the three measurements at the resulting measurement angle. Lithographic printing Page 37 1251663 VI. Scope of Application Patent 15. A method of measuring parameters in a lithographic printing apparatus as described in claim 12, wherein the light source based tool comprises a plurality of laser beam sources. 16. A method of measuring a parameter in a lithographic apparatus according to claim 12, wherein the light source based tool comprises an incident wide reflective light source, an incident that focuses and illuminates the light through a range A wavelength optical system, and a detector that measures the diffraction characteristics of the resulting measurement wavelength. 17. A method of measuring a parameter in a lithographic apparatus according to claim 12, wherein the light source based tool comprises an incident light source that changes the amplitude and orientation of the S and P polarizations. Element, and a detector that detects the diffraction characteristics of the detection direction. 18. A method of measuring a parameter in a lithographic apparatus according to the first aspect of the invention, wherein the measurement of a diffraction characteristic comprises a direction of a tool source based on a broad reflection radiation source. Measurement, operation at a fixed angle, a change angle of 0 or a change angle must be. 19. A method of measuring a parameter relating to a lithographic apparatus according to the first aspect of the invention, wherein the measurement of a diffraction characteristic comprises a position measurement by a tool source based on a single wavelength radiation source Operating at a fixed angle, a varying angle 0 or a varying angle φ 〇 20. A method for measuring parameters in a lithographic apparatus as described in the first paragraph of the patent application, wherein the measurement of a diffraction characteristic comprises A direction measurement made by a tool source based on multiple discrete sources. Page 38 1251663 This method forms a central 〇 twenty-five method, its process chart; focal length and surface; or twenty-five method, one of the measurements described in relation to lithography where the diffraction characteristic is a reflective diffraction One of the measurements described in relation to lithographic printing wherein the diffraction characteristic is a conductive diffraction characteristic, one of the measurements relating to lithographic printing wherein the diffraction characteristic is a reflection level diffraction A measurement relating to lithographic printing in which the diffraction characteristics are a more advanced diffraction feature relating to lithographic printing further comprises the use of a printing apparatus in a plurality of diffraction structures, wherein the parameters are six, the scope of the patent application is 21. The method of the parameters in the device, sex. 22. The method of applying the parameters in the device of the patent scope, sex. 2 3. The method of applying the parameters in the device of the patent scope, sex. 24. The method of applying the parameters in the device of the patent scope, sex. - 25. The method of applying the parameters in the device of the patent range, a known different focal length setting is the focal length in the printing device 2 6. The parameters of the parameters in the printing device of the patent application range vary according to the focal length. The difference between the square sections is plotted as a rate of change; the maximum break is determined. 2. 7. The different focal lengths of the parameters of the parameters in the printing device of the patent application range. One of the measurements described in relation to the lithographic metric includes: drawing the section to map the change in the adjacent focal length to the diffraction structure; determining the minimum section in the section. One of the measurements described in the lithographic version is known to have different focal lengths set to equal increase Page 39 1251663 VI. Scope of Patent Application 2 8. A method for measuring parameters in a lithographic apparatus as described in claim 25, wherein different focal lengths are known to be set to unequal increments of different focal lengths. The settings, and the method further includes using a mathematical algorithm to normalize the different focal length settings of the unequal increments. 29. A method of measuring a parameter relating to a lithographic apparatus as recited in claim 25, wherein the section between the cross-section or the diffractive structure has a variation of the difference of approximately a parabolic curve with a tangent of zero The position is 'heart 〇' in the focal length. 3 0. A method for measuring parameters in a lithographic apparatus as described in the first paragraph of the patent application, the method further comprising forming a winding at the same focal length setting by using a printing apparatus The structure is complex and determines the difference that varies with the location of the diffractive structure on the substrate. 31. A method of measuring a parameter in a lithographic apparatus as described in the first paragraph of the patent application, the method further comprising forming a diffraction using a printing apparatus at a known different focal length setting and a different dose setting. The structure is complex and determines the effect of the dose on the focal length. 3 2. A method of measuring a parameter in a lithographic apparatus according to claim 31, wherein the diffractive structure comprises a set of diffractive structures of the same known different focal lengths, and The dose is set to change and change. 3 3. A method for determining a focal length center in a printing apparatus, the method comprising: providing a base of a plurality of diffraction structures generated by a printing apparatus, wherein the diffraction structure comprises a plurality of different known Focal length setting; measuring the diffraction of at least three diffractive structures using a radiation-based tool Page 40 1251663 VI. Characteristics of the scope of application for patents; provide a theoretical database of theoretical diffraction characteristics of a theoretical diffraction structure; determine an optimal theoretical diffraction characteristic that meets the diffraction characteristics of each measurement; A theoretical diffraction structure calculates its section to provide a theoretically optimal diffraction characteristic; and determines the focal length center, the focal length setting having a minimum of the difference between the sections of the diffraction grating set by the adjacent focal length. 34. A method for determining a focal length center in a printing apparatus as recited in claim 33, wherein the difference between the cross-sections of the adjacent focal length setting diffraction structures is approximately a parabolic curve, and the tangent is zero The smallest difference. 3 5. A method for determining a focal length center in a printing apparatus as described in claim 33, wherein the minimum difference decision comprises a data set obtained by setting a difference between the cross-sections of the diffraction gratings by adjacent consecutive focal lengths. On a parabolic curve, the smallest difference includes the smallest of the parabolic curves. 6. A method for determining the focal length center in a printing apparatus as described in claim 33, wherein different focal lengths are set to be diffracted. The section of the structure is drawn as an equation that varies with focal length. 37. A method of determining a focal length center in a printing apparatus as described in claim 33, wherein the diffraction structure is a single cycle, a bi-period, or a multi-cycle structure. 38. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the cross-section is a cross-sectional area. 39. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the cross section is a cross-sectional volume. 40. One of the types described in claim 33 of the patent application is in a printing device Page 41 1251663 VI. Scope of Application Patent The method of determining the center of the focal length, where the section provides a sum of two or more parameters in a theoretical diffraction structure that conforms to the theoretical diffraction characteristics. 41. A method of determining a focal length center in a printing apparatus as recited in claim 40, wherein one parameter is a critical dimension. 4 2. A method of determining a focal length center in a printing apparatus as claimed in claim 33, wherein the substrate comprises a wafer. 43. A method for determining the center of focus in a printing device as described in claim 33, wherein the radiation source-based kit includes a light source-based tool. 4 4. A method for determining a focal length center in a printing apparatus as described in claim 43 of the patent application, wherein the light source based tool comprises an incident laser beam source, and a laser beam is focused and fired. A detector that measures the diffraction characteristics at an angle through a range of incident angles and a pain test result. 45. A method of determining a focal length center in a printing apparatus as described in claim 44, wherein the light source based tool comprises an angle resolved scatterometer. 46. A method of determining a focal length center in a printing apparatus as described in claim 43 of the patent application, wherein the light source based tool comprises a plurality of laser beam sources. 4 7. A method for determining a focal length center in a printing apparatus according to claim 43 of the patent application, wherein the light source-based tool comprises an _ incident wide reflection light source, and a light source is focused and illuminated by the light source. Range of in-shooting wavelengths, and the resulting diffraction characteristics of the resulting measurement wavelength Page 42 1251663 VI. Application for patent scope Detector. 4 8. A method for determining a focal length center in a printing apparatus as described in claim 43 wherein the light source based tool comprises an incident light source that varies the amplitude and orientation of the S and P polarizations. A component that directs the light source to focus and illumination through a range of incident orientations, and a detector that detects the direction of the diffraction characteristics of the resulting image. 49. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the measuring of the diffraction characteristic comprises the use of a position measurement based on a tool source based on a wide reflected radiation source Operates at a fixed angle, a varying angle β or a varying angle of 0. 50. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the measuring of the diffraction characteristic comprises a position measurement using a tool source based on a single wavelength radiation source , operates at a fixed angle, a varying angle Θ or a varying angle φ. 51. A method of determining a focal length center in a printing apparatus as described in claim 33, wherein the measuring of the diffraction characteristic comprises using a tool source based on a plurality of discrete wavelength radiation sources. Measurement the amount. 5 2. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the diffraction characteristic is a reflective diffraction characteristic. 53. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the diffraction characteristic is a conductive diffraction characteristic. 5 4. In the printing equipment as described in the thirty-third patent application scope Page 43 1251663 VI. Scope of Application Patent The method of determining the center of the focal length, in which the diffraction characteristic is the diffraction characteristic of the reflection level. 5 5. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the diffraction characteristic is a higher order diffractive characteristic. 56. A method of determining a focal length center in a printing apparatus as recited in claim 33, wherein the different focal length settings comprise constant differences between different focal length settings. 57. A method for determining a focal length center in a printing apparatus as described in claim 33, wherein different known focal lengths are set to different focal lengths of non-equal distance, the method further comprising using a mathematics The algorithm is used to normalize the different focal length settings of the non-equal distance. 5 8. A method of determining a focal length center in a printing apparatus as claimed in claim 33, wherein the diffraction structure is a latent image diffraction structure. 5 9. A method of determining a focal length center in a printing apparatus as described in claim 33, wherein the substrate is a wafer 5 whose wafer has not been subjected to a development process. 6 0. A method of flow control in a focal length center of a printing apparatus, the method comprising the steps of: providing a substrate having a latent image of a diffraction pattern generated by a printing device, the diffraction structure comprising a plurality of different Knowing the focal length setting; using a radiation-based tool to measure the diffraction characteristics of at least three complex image diffraction structures; providing a theoretical database of theoretical diffraction characteristics of the theoretical diffraction structure Determining a theoretical diffraction characteristic that best matches each measurement and diffraction characteristic; for each theory Page 44 1251663 VI. Apply for patent-specific diffraction structure to calculate its section to provide a theoretically perfect diffraction characteristic; determine a focal length center as a focal length setting, where adjacent focal lengths set the latent image diffraction structure The difference in the cross-section is minimal; and the focal length setting in the printing device is adjusted to the determined focal length center. 61. A method of flow control in a focal length center of a printing apparatus as claimed in claim 60, wherein the adjustment of the focus setting in the printing apparatus comprises a computer based control system. 6 2. A method of flow control in a focal length center of a printing apparatus as claimed in claim 60, wherein the adjustment of the focus setting in the printing apparatus comprises an autofocus control system, at least one of which is input to the autofocus The system's data contains a parameter related to the difference between the sections. Page 45