JP2005259771A - Device and method for correcting pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method for correcting pattern by which the position of a mask pattern composed of through holes formed by releasing the stress of a thin film can be corrected accurately by quickly and accurately calculating the displacement of the pattern. <P>SOLUTION: The relation between an experimentally found characteristic value and a stiffness matrix is entered in advance in a database. The stiffness matrix becomes to conform to a mask which becomes an actual object to be processed. In a pattern correcting process, a mask pattern to be processed is divided into unit areas (ST21), and the characteristic value of the mask pattern is calculated at every unit area (ST22). Then the stiffness matrix is found at every unit area by referring to the data base (ST23), and the displacement of the mask pattern is found at every unit area by solving a stiffness equation by using the stiffness matrix (ST24). In addition, the position of the mask pattern is corrected at every unit area in accordance with the found displacement of the mask pattern. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, in particular, in a mask in which a through-hole of a mask pattern is formed in a thin film, the mask pattern made of the through-hole is displaced in advance in consideration of the displacement of the mask pattern formed by the through-hole due to the stress release of the thin film. The present invention relates to a pattern correction apparatus and a pattern correction method for obtaining an amount and correcting a position of a mask pattern in advance with the obtained displacement.

  In the same-magnification stencil mask used for low-energy electron beam proximity projection lithography (LEEEP), the same pattern position (IP) accuracy as that required on the wafer is required for the mask. Further, unlike the photomask, in the above-mentioned equal-magnification stencil mask, a mask pattern consisting of through holes is formed on a membrane having a thickness of 1 μm or less with low mechanical rigidity, so pattern position control is a very important issue. .

  Pattern position errors can be classified into (1) global errors caused by the deformation of the mask substrate over the entire mask surface and (2) local errors occurring in one membrane. The latter is caused not only by the accuracy of the electron beam (EB) drawing apparatus at the time of manufacturing the mask but also by the arrangement of the pattern in the membrane. In general, a pattern formed by a through hole on a membrane is deformed when the membrane is pulled, and the position is also shifted. Also in the case of a stencil mask, a local error of the pattern occurs due to a tensile stress (usually several MPa to several tens MPa) for allowing the membrane to stand by itself without bending.

  In order to solve this problem, two methods have been proposed (see Patent Documents 1 and 2). The basic idea of these methods is to calculate the displacement of a given mask pattern by the finite element method (FEM) and correct the pattern position in the opposite direction to the displacement in advance. . Since it is impossible in terms of calculation time to strictly execute the finite element method for the pattern on the actual stencil mask, the above Patent Documents 1 and 2 disclose speed-up approximation methods, respectively. .

  The method described in Patent Document 1 is a method of solving the stiffness equation by converting the pattern density in each finite element into the thickness of the finite element, which is effective for a contact layer or the like, but has a large pattern aspect ratio. For different wiring patterns and the like, the accuracy is lowered. This is because the displacement anisotropy due to the pattern anisotropy cannot be analyzed only by changing the thickness of the finite element.

  In the method described in Patent Document 2, the mask pattern is divided into unit regions, and the corresponding stiffness matrix is calculated by the accurate finite element method for the characteristic values that characterize the pattern (such as the pattern density for the contact layer). The correspondence relationship is stored in a database in advance. For a mask pattern to be processed, a characteristic value is calculated for each unit area, and a corresponding stiffness matrix is obtained by referring to a database. As a result, the stiffness matrix can be obtained at high speed without performing an accurate calculation by the finite element method for each mask data to be processed.

JP 2003-017397 A JP 2003-318084 A

  However, physical parameters such as Young's modulus and Poisson's ratio are required as input parameters necessary for calculation by the finite element method, and the internal stress of the membrane must be experimentally measured. The literature values are generally used as the physical property values, but the mask membrane does not always have the same values as the literature values measured for the bulk crystal. In addition, the measurement value of the internal stress includes an error.

  For example, for a sample in which the internal stress of a membrane made of a silicon single crystal having a thickness of 500 nm and 1 mm square is adjusted to 25 MPa by boron doping, and a contact hole is processed so that the area density is 15% in the left half of the membrane. The local position error of the pattern was measured with a Leica coordinate measuring instrument LMS IPRO. Moreover, the calculation by the finite element method of patent document 2 was performed with respect to the same pattern.

  FIG. 12A shows the actually measured local position error, and FIG. 12B shows the result by the finite element method. As shown in FIG. 12, it can be seen that the agreement between the two is not good. This is because there are errors in the physical property values used in the calculation and the measured values of internal stress.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to calculate the displacement of the mask pattern formed of the through-hole due to the stress release of the thin film at high speed and accurately and correct the mask pattern position correction. It is an object of the present invention to provide a pattern correction apparatus and a pattern correction method that can be performed at the same time.

  In order to achieve the above object, the pattern correction apparatus according to the present invention provides a mask in which a through hole of a mask pattern is formed in a thin film, and the mask pattern of the through hole is released by stress release of the thin film by forming the through hole. A pattern correction apparatus that corrects the position of the mask pattern on the data in advance in consideration of displacement, and a characteristic value that characterizes the mask pattern in the unit region obtained experimentally in advance and the unit A storage unit for storing the relationship with the stiffness matrix in the region, a dividing unit for dividing the mask pattern to be processed into the unit regions, and obtaining the characteristic value of the mask pattern for each of the divided unit regions Characteristic value calculation means, and rigidity matrix calculation for obtaining the rigidity matrix corresponding to the characteristic value for each unit region from the storage unit A pattern displacement calculating means for solving the stiffness equation using the stiffness matrix and obtaining the displacement of the mask pattern for each unit region; and for each unit region according to the obtained displacement of the mask pattern. Pattern position correcting means for correcting the position of the mask pattern.

In the pattern correction apparatus of the present invention described above, the relationship between the characteristic value and the stiffness matrix obtained experimentally in advance is stored in the storage unit. Therefore, the stiffness matrix matches the mask to be actually processed.
In the pattern correction process, first, the mask pattern to be processed is divided into unit areas by the dividing unit, and the characteristic value of the mask pattern is calculated for each unit area by the characteristic value calculating unit.
Then, using the relationship between the characteristic value stored in the storage unit and the stiffness matrix, the stiffness matrix calculation means obtains the stiffness matrix for each unit region.
Then, the displacement of the mask pattern is obtained for each unit region by solving the stiffness equation using the stiffness matrix by the pattern displacement calculating means.
The position of the mask pattern is corrected for each unit area by the pattern position correction means in accordance with the obtained pattern displacement.

  In order to achieve the above object, according to the pattern correction method of the present invention, in the mask in which the through hole of the mask pattern is formed in the thin film, the mask pattern of the through hole is formed by releasing the stress of the thin film by forming the through hole. A pattern correction method for correcting in advance the position of the mask pattern on data in consideration of displacement, a characteristic value for graphically characterizing the mask pattern in a unit region and a stiffness matrix in the unit region A step of experimentally obtaining a relationship with the database, a step of dividing the mask pattern to be processed into the unit regions, and a step of obtaining the characteristic value of the mask pattern for each of the divided unit regions And referring to the database, the rigidity matrix corresponding to the characteristic value of the unit area to be processed. In accordance with the step of determining the mask pattern for each unit region, solving the stiffness equation using the stiffness matrix, determining the displacement of the mask pattern for each unit region, and according to the determined displacement of the mask pattern, Correcting the position of the mask pattern for each unit region.

In the pattern correction method of the present invention, the relationship between the experimentally obtained characteristic value and the stiffness matrix is stored in a database in advance. Therefore, the stiffness matrix matches the mask to be actually processed.
In the pattern correction process, first, a mask pattern to be processed is divided into unit areas, and a characteristic value of the mask pattern is calculated for each unit area.
Next, the stiffness matrix is obtained for each unit region with reference to the database, and the displacement of the mask pattern is obtained for each unit region by solving the stiffness equation using the stiffness matrix.
The pattern correction process is completed by correcting the position of the mask pattern for each unit area in accordance with the obtained pattern displacement.

  According to the pattern correction apparatus and the pattern correction method of the present invention, the displacement of the mask pattern formed of the through-hole due to the stress release of the thin film can be calculated at high speed and accurately, and the position correction of the mask pattern can be performed accurately. .

  Embodiments of a pattern correction apparatus and a pattern correction method of the present invention will be described below with reference to the drawings.

  Conventionally, a database that gives a relationship between a characteristic value that characterizes a mask pattern graphically and a stiffness matrix has been created by the finite element method. That is, the stiffness matrix is calculated by applying an external force to the virtual system and solving the stiffness equation from the deformation of the membrane. In the present invention, by performing this part experimentally, the above-described error factors are eliminated and a more realistic stiffness matrix is experimentally calculated. That is, for a test mask manufactured by the same process as the production mask, the displacement of the four corners of the unit area is measured with a coordinate measuring instrument, and the stiffness equation is solved to calculate the experimental stiffness matrix and create a database To do.

  FIG. 1 is a plan view of a test mask used for experimentally determining the relationship between the characteristic value and the stiffness matrix.

  In the test mask 1 shown in FIG. 1, a plurality of membranes (thin films) 3 are formed on a thick substrate 2, and beams 4 for partitioning the membranes 3 are formed to reinforce the strength of the membrane 3. The substrate material and mask manufacturing process described above are exactly the same as the production mask. Therefore, the conditions of the internal stress adjustment process of the membrane 3 as well as the thickness of the substrate 2 and the membrane 3 are the same. For example, in the production mask, for example, the thickness of the substrate 2 and the beam 4 is about 700 μm, and the thickness of the membrane 3 is about 500 nm.

  Next, a range of characteristic values and a step width for creating a database of characteristic values and a stiffness matrix are determined. This takes a step width such that the stiffness matrix for an arbitrary characteristic value can be accurately interpolated from the database curve, and is set so as to sufficiently cover the range of characteristic values assumed in the actual device pattern. For example, in the case of a contact layer, an actual device pattern is examined. If the area density is about 0% (region without pattern) to about 30%, the characteristic value is changed in increments of 5%, for example, and 6 points ( It is sufficient to experimentally calculate the stiffness matrix. If an accurate database cannot be created without setting multiple types of characteristic values outside the contact layer, more experiments are required.

  Further, in the pattern local position error correction process, the grid width for calculating the pattern position error is determined. The grid width defines the dimension of one side of the unit area. For example, when the production mask has a 1 mm square membrane, the position error is calculated in units of 250 μm, and the error at the intermediate points may be interpolated from the values on the grid points. In this case, the stiffness matrix is calculated for each unit area of 250 μm square.

  A membrane 3 larger than the grid width is formed on the test mask 1 shown in FIG. Then, a unit region is set in the central region of each membrane 3, and a pattern whose characteristic value is changed is arranged in the unit region. FIG. 2A is a diagram illustrating an example of a pattern arranged in a unit region of one membrane 3.

  As shown in FIG. 2A, a unit area Ar defined by the grid width G is set in the central area of one membrane 3. Position measurement marks M for measuring pattern displacement with a coordinate measuring instrument are arranged at the four corners of the unit area Ar. The position measurement mark M is, for example, a cross mark of several μm to several tens of μm.

  After the through hole of the mask pattern P is formed in the membrane 3 in the unit region Ar, the position of the position measurement mark M is measured one after another by a coordinate measuring instrument. As shown in FIG. 2B, the unit region Ar in the membrane 3 can be regarded as a finite element composed of four nodes N. Finite elements have equivalent stiffness, which is represented by an elastic stress-strain matrix. The four nodes N are pulled outward by the internal stress F of the membrane 3 surrounding the periphery. The force is unknown, but takes the same absolute value in the X and Y directions due to the symmetry of the system. The displacement of the node N is obtained from the measurement result of the position measurement mark M arranged at the position of the node N. The force acting on the node N and the displacement are related by the stiffness equation shown in the following equation (1). Therefore, by solving the stiffness equation of Equation (1), the stiffness matrix of the unit region corresponding to a certain characteristic value and the internal stress of the membrane 3 can be obtained from the displacement of the node N. The internal stress on the same mask should basically take a common value even if there is a process variation, so that the calculation result of the internal stress for each membrane 3 is almost the same value. Therefore, when the process does not change, the value of the internal stress calculated once (average value in the membrane) can be used as a constant thereafter.

[Equation 1]
{F} = [K] {U} (1)

  In the above formula (1), {F} indicates a load vector of the force F acting on each node. {U} is a displacement vector indicating the displacement direction and displacement amount of the node position. [K] is a stiffness matrix of the element (unit region). The stiffness matrix [K] is a value indicating the relationship between stress and displacement. When dealing with planar problems, such as stencil masks, the stiffness matrix is a 3 × 3 matrix.

  In the above method, a conventional procedure of applying a virtual external force on a simulation to a unit region having a certain characteristic value, calculating a displacement caused by a finite element method, and calculating a stiffness matrix therefrom, This was done experimentally. The method of the present invention can be said to be a more accurate method in the sense that it is not necessary to input physical property values such as Young's modulus and Poisson's ratio, and internal stress calculation values of the membrane.

  By obtaining a stiffness matrix for each unit region in which patterns having various property values are arranged, the relationship between the property values and the stiffness matrix is represented by a table or function. FIG. 3 is an example in which the relationship between the characteristic value and the stiffness matrix is expressed as a function. In the figure, the horizontal axis represents the characteristic value ψ, and the vertical axis represents the stiffness matrix [K]. For each of a plurality of characteristic values, a rigidity matrix is experimentally obtained, and the relationship between the characteristic values and the rigidity matrix as shown in FIG. 3 is obtained by interpolating the rigidity matrix between the obtained characteristic values.

  FIG. 4 is a schematic configuration diagram of the pattern correction apparatus according to the present embodiment. The pattern correction apparatus according to the present embodiment converts design data D1 into drawing data D2.

  The pattern correction apparatus shown in FIG. 4 includes a storage unit 10, a complementary division unit 11, a unit area division unit 12, a characteristic value calculation unit 13, a stiffness matrix calculation unit 14, a pattern displacement calculation unit 15, and a pattern position. And correction means 16.

  The design data D1 includes a design pattern to be transferred to a wafer that is an exposure target using a stencil mask.

  The drawing data D2 includes a mask pattern formed as a through hole in the stencil mask. The pattern arrangement is different between the design pattern and the mask pattern. This is because in the stencil mask, a donut pattern or the like cannot be formed by a through-hole, and a mask pattern cannot be arranged at a place where a beam exists. Therefore, the design pattern cannot be formed as a through hole in the stencil mask with the arrangement as it is, and it is usually necessary to divide the design pattern in a complementary manner. Further, even if the mask pattern through-hole is formed at a predetermined position as described above, the mask pattern position is shifted due to the stress release of the membrane 3 due to the formation of the through-hole. This is because the mask pattern forming position needs to be corrected in advance by the amount of displacement of the mask pattern.

  The storage means 10 is a database of the experimentally obtained relationship between the characteristic value that graphically characterizes the mask pattern in the unit area and the stiffness matrix of the unit area as described above.

  Complementary division means 11 performs complementary division processing on the design pattern to create a mask pattern to be placed on the mask. Normally, the drawing data D2 is created from the design data D1 in one apparatus, but the complementary division processing can also be performed in another apparatus.

  The unit area dividing means 12 divides the mask pattern subjected to the complementary division processing by the complementary dividing means 11 into each unit area. This unit area has the same dimensions as the unit area Ar shown in FIG. 2A set for experimentally determining the relationship between the characteristic values stored in the storage means 10 and the stiffness matrix.

  The characteristic value calculating unit 13 calculates the characteristic value of the mask pattern included in the unit area for each unit area divided by the unit area dividing unit 12. For example, in the case of a contact hole pattern, the pattern density is calculated as the characteristic value.

  The stiffness matrix calculating unit 14 corresponds to the characteristic value ψ calculated by the characteristic value calculating unit 13 based on a table or function indicating the relationship between the characteristic value ψ stored in the storage unit 10 and the stiffness matrix [K]. The stiffness matrix [K] is calculated for each unit region.

  The pattern displacement calculation means 15 solves the stiffness equation of the above equation (1) using the stiffness matrix obtained by the stiffness matrix calculation means 14 and obtains the displacement of the mask pattern for each unit area. The pattern displacement is a vector including a displacement amount and a direction.

  The pattern position correcting unit 16 corrects the position of the mask pattern for each unit area according to the pattern displacement obtained by the pattern displacement calculating unit 15. For example, the position of the mask pattern is shifted in the opposite direction to the pattern displacement.

  Next, an outline of a pattern correction method for obtaining drawing data from design data by the pattern correction apparatus will be described with reference to the flowchart of FIG.

  First, the complementary division means 11 performs complementary division processing on the design pattern to create a mask pattern to be placed on the mask (step ST1). Then, the unit region dividing unit 12, the characteristic value calculating unit 13, the stiffness matrix calculating unit 14, and the pattern displacement calculating unit 15 calculate a pattern displacement using a finite element method accompanied by high-speed approximation (step ST2).

  After the pattern displacement is calculated, the pattern position correcting unit 16 performs, for example, a correction process for shifting the position of the mask pattern in the reverse direction according to the pattern displacement for each unit region (step ST3). The corrected mask pattern is the drawing data.

  FIG. 6 is a flowchart for explaining step ST2 of FIG. 5 in detail.

  In step ST2, first, the unit area dividing means 12 divides the mask pattern subjected to complementary division processing into unit areas (step ST21).

  Next, the characteristic value calculation means 13 calculates the characteristic value of the mask pattern included in the unit area for each divided unit area (step ST22). For example, in the case of a contact hole pattern, the pattern density is calculated as the characteristic value.

  As shown in FIG. 7, when there is a mask pattern to be placed on the production mask 100, a mask pattern placed on one membrane 3 at the upper left of the production mask 100 will be considered. FIG. 7 shows an example in which one membrane 3 is divided into 4 × 4 unit areas Ar. In step ST22, the characteristic value ψ of each unit region Ar of one membrane 3 shown in FIG. 7 is calculated.

  Next, the characteristic value ψ calculated by the characteristic value calculating unit 13 based on the table or function indicating the relationship between the characteristic value ψ stored in the storage unit 10 and the rigidity matrix [K] by the stiffness matrix calculating unit 14. Is calculated for each unit region (step ST23). For example, based on the relationship between the characteristic value ψ and the stiffness matrix [K] as shown in FIG. 3 stored in the storage means 10, as shown in FIG. 8, the stiffness matrix [each unit region Ar of the membrane 3 [ K] is calculated.

  Next, the pattern displacement calculation means 15 solves the stiffness equation using the obtained stiffness matrix to determine the displacement of the mask pattern for each unit region (step ST24). The pattern displacement is a vector including a displacement amount and a direction. By performing the process of obtaining the pattern displacement for each unit area Ar on all the membranes 3, as shown by the dotted lines in FIG. 8, the local error (local displacement) of each membrane 3 in the production mask 100 is obtained.

  As described above, according to the pattern correction apparatus and the pattern correction method according to the present embodiment, by experimentally calculating the stiffness matrix and the internal stress corresponding to the characteristic values that characterize the mask pattern graphically, A stiffness matrix that matches the actual production mask is obtained. That is, a stiffness matrix is calculated using literature values as physical properties such as Young's modulus and Poisson's ratio, and a more accurate stiffness matrix and internal stress can be obtained as compared to the case where the membrane internal stress also uses literature values.

  Then, the characteristic value of the mask pattern is obtained for each unit area with respect to the mask to be processed, and the stiffness matrix corresponding to the characteristic value is obtained using the relationship between the property value and the stiffness matrix obtained experimentally in advance. Then, by solving the stiffness equation using the stiffness matrix and obtaining the displacement of the mask pattern for each unit region, it is possible to obtain the pattern displacement quickly and accurately without performing an accurate finite element method calculation. .

  Accordingly, the mask pattern position accuracy can be improved by correcting the position of the mask pattern for each unit region in accordance with the obtained pattern displacement. By improving the position accuracy of the mask pattern, it is possible to improve the overlay accuracy of the pattern at the time of device manufacture, and to improve the device yield and performance.

(Other examples of characteristic value ψ)
In the above embodiment, as an example of the characteristic value ψ, an example using a pattern density has been described for a contact hole pattern, for example. However, since there is no information about the pattern anisotropy (direction) in the characteristic value ψ only with the pattern density, the anisotropy of the pattern displacement cannot be calculated. Accordingly, when there is anisotropy of the pattern in the X direction and the Y direction, particularly in the case of a wiring pattern, it is preferable to use the characteristic values shown in the following (1) to (2) or use them together.

  (1) As the characteristic value ψ, the ratio of the total value of the X-axis direction components of the perimeter of the pattern in the unit area and the total value of the Y-axis direction components is obtained. For example, as shown in FIG. 9, it is assumed that a plurality of mask patterns P are arranged in the unit region Ar. FIG. 9 shows a mask pattern P in which the shaded portion is the membrane 3 and the portions other than the shaded portion are through holes.

  FIG. 10 is an enlarged view of only the mask pattern P portion of FIG. As shown in FIG. 10, the lengths of the sides of each mask pattern P in the X-axis direction are A to L, and the lengths of the sides of each mask pattern P in the Y-axis direction are a to l. In this case, the characteristic value ψ is expressed by the following equation (2). The characteristic value ψ in this case can be considered as the aspect ratio of the entire mask pattern in the unit area Ar.

[Equation 2]
ψ = (A + B +... + K + L) / (a + b +... + k + l) (2)

  (2) As the characteristic value ψ, ψx, which is a ratio determined based on the length of the mask pattern P in the unit area Ar projected on the X axis, and the mask pattern in the unit area Ar are projected on the Y axis. A ratio (ψx / ψy) with ψy, which is a ratio determined based on the length to be determined. The mask pattern P in the unit area Ar shown in FIG. 9 will be described as an example. As shown in FIG. 11, the length of the portion (projection FX) of the entire unit area Ar projected on the X axis is Lfx. Let Lpx be the length of the portion (projection PX) projected on the X axis of at least one mask pattern P in the unit area Ar.

  In addition, the length of a portion (projection FX) of the entire unit area Ar projected on the Y axis is Lfy. In the present embodiment, Lfx = Lfy. Let Lpy1 to Lpy4 be the lengths of the portions (projections PY1 to PY4) projected on the Y axis of at least one mask pattern P in the unit region Ar. Here, it is assumed that the ratio between the projection length of the unit area Ar and the length of the mask pattern P is ψx and ψy. Therefore, ψx and ψy are expressed by the following equations (3) and (4). From these, the characteristic value (ψ = ψx / ψy) is obtained.

[Equation 3]
ψx = Lpx / Lfx (3)

[Equation 4]
ψy = (Lpy1 + Lpy2 + Lpy3 + Lpy4) / Lfy (4)

  As described above, the characteristic value ψ in which the above (1) and (2) are used alone or in combination with the pattern density is used, and the rigidity matrix corresponding to the characteristic value ψ is experimentally obtained, so that the direction to the pattern is obtained. Even when anisotropic pattern displacement occurs, accurate pattern correction can be performed at high speed.

The present invention is not limited to the description of the above embodiment.
For example, although some examples of characteristic values have been described in the above-described embodiment, there is no particular limitation as long as the directionality of patterns in the X direction and the Y direction can be shown. In the present embodiment, an example in which only the displacement amount is corrected in the direction opposite to the pattern displacement based on the pattern displacement has been described, but the correction amount is not limited. Further, after the pattern correction is performed once in step 3, the process returns to step 2 again to further determine the displacement of the corrected mask pattern, and repeat the pattern displacement analysis and the pattern correction processing until it approaches the ideal value. Good.

Further, the mask pattern to be processed may be any stencil mask in which the pattern is formed by a through hole. The pattern correction apparatus and pattern correction method of the present invention can be applied to a mask pattern of a stencil mask used for electron beam equal magnification exposure, electron beam reduced projection exposure, and ion beam exposure. Further, the present invention can be applied to a mask pattern of a stencil mask used for processes other than lithography such as ion implantation.
In addition, various modifications can be made without departing from the scope of the present invention.

It is a top view of the test mask used in order to obtain | require experimentally the relationship between a characteristic value and a rigidity matrix. It is a figure for demonstrating the process which measures the pattern displacement of the mask pattern which has a certain characteristic value with a coordinate measuring device. It is a figure which shows the relationship between a characteristic value and a rigidity matrix. It is a schematic block diagram of the pattern correction apparatus which concerns on this embodiment. It is a flowchart of the pattern correction method according to the present embodiment. It is a flowchart for demonstrating in detail step ST2 of FIG. It is a figure for demonstrating the process which calculates | requires the characteristic value of each unit area | region. It is a figure for demonstrating the process which calculates | requires the rigidity matrix of each unit area | region, and calculates | requires a pattern displacement using the said rigidity matrix. It is a figure for demonstrating the other example of a characteristic value. It is a figure for demonstrating the other example of a characteristic value. It is a figure for demonstrating the other example of a characteristic value. It is a figure for demonstrating the problem of the pattern correction process which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Test mask, 2 ... Board | substrate, 3 ... Membrane, 4 ... Beam, 10 ... Memory | storage means, 11 ... Complementary division | segmentation means, 12 ... Unit area division | segmentation means, 13 ... Characteristic value calculation means, 14 ... Stiffness matrix calculation means, 15 ... Pattern displacement calculating means, 16 ... pattern position correcting means, D1 ... design data, D2 ... drawing data, 100 ... production mask, Ar ... unit area, M ... position measuring mark, N ... node, F ... force, P ... Mask pattern

Claims (5)

In the mask in which the through hole of the mask pattern is formed in the thin film, the position of the mask pattern on the data is considered in consideration that the mask pattern of the through hole is displaced by stress release of the thin film due to the formation of the through hole. A pattern correction apparatus for correcting
A storage unit for storing a relationship between a characteristic value that graphically characterizes a mask pattern in a unit region obtained experimentally in advance and a stiffness matrix in the unit region;
A dividing means for dividing the mask pattern to be processed into the unit areas;
Characteristic value calculation means for obtaining the characteristic value of the mask pattern for each of the divided unit areas;
Stiffness matrix calculation means for obtaining, for each unit region, the stiffness matrix corresponding to the characteristic value from the storage unit;
A pattern displacement calculating means for solving a stiffness equation using the stiffness matrix and obtaining a displacement of the mask pattern for each unit region;
A pattern correction apparatus comprising: pattern position correction means for correcting the position of the mask pattern for each unit region in accordance with the obtained displacement of the mask pattern. The pattern correction apparatus according to claim 1, further comprising complementary division means for generating a mask pattern to be arranged on the mask by complementary division of a design pattern. In the mask in which the through hole of the mask pattern is formed in the thin film, the position of the mask pattern on the data is considered in consideration that the mask pattern of the through hole is displaced by stress release of the thin film due to the formation of the through hole. Is a pattern correction method for correcting in advance,
A step of experimentally obtaining in advance a database of a characteristic value that characterizes the mask pattern in the unit region and a stiffness matrix in the unit region;
Dividing the mask pattern to be processed into the unit regions;
Obtaining the characteristic value of the mask pattern for each of the divided unit regions;
With reference to the database, obtaining the rigidity matrix corresponding to the characteristic value of the unit region to be processed for each unit region;
Solving a stiffness equation using the stiffness matrix to determine a displacement of the mask pattern for each unit region;
And correcting the position of the mask pattern for each unit region according to the obtained displacement of the mask pattern. The step of preliminarily experimentally determining the relationship between the characteristic value characterizing the mask pattern in the unit region and the rigidity matrix in the unit region in advance is a database.
By using the same process as the mask to be processed, mask blanks divided into a plurality of thin films by a beam are prepared, the unit areas are set in each thin film, and position measurement marks are formed at the corners of the unit areas. Steps,
Forming a plurality of mask patterns with varying characteristic values in the thin film in each unit region by the through holes;
Measuring a position of the position measurement mark in the unit region, and obtaining a displacement of the position measurement mark by forming the mask pattern;
Solving a stiffness equation using the displacement of the position measurement mark to obtain an internal stress of the thin film and a stiffness matrix corresponding to the characteristic value;
The pattern correction method according to claim 3, further comprising: creating a database of relationships between the characteristic values and the stiffness matrix. The pattern correction method according to claim 3, further comprising the step of creating a mask pattern to be processed by complementary division of a design pattern before the step of dividing the mask pattern to be processed into the unit regions.

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