JP2009223262A - Exposure system and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To positively form a pattern conforming to an exposure object plane on a substrate or the like without deteriorating throughput. <P>SOLUTION: When the substrate is carried into a lithographic system, a position of an alignment mark formed on the exposure object plane is detected, and a corrected alignment mark is calculated from an error amount of mark intervals of the alignment mark and a reference alignment mark of a first plane. An index St is calculated, being a mean difference between the mark interval SLnm of the corrected alignment mark, and the measured mark interval MLnm of the alignment mark. In the same way, an index Sb with respect to a second plane is calculated. When St<Sb, it is determined that the first plane is the exposure object plane, and a lithographic process is carried out on the basis of lithographic data of the first plane. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an exposure system and an exposure method for forming a pattern on an electronic circuit board or the like. In particular, the present invention relates to determination of the front and back of a substrate that can form a pattern on both sides.

  In the substrate manufacturing process, pattern forming exposure processing is performed on a substrate coated with and coated with a photosensitive material such as a photoresist, using an exposure apparatus that uses a mask (reticle) or a maskless drawing apparatus. . In a drawing apparatus, an exposure unit (light) that scans an exposure surface by modulating an electron beam or a laser beam, or two-dimensionally arrayed spatial light modulation elements (cells) such as a DMD (Digital Micro-mirror Device). The exposure surface is scanned using a modulator. After the drawing process, processes such as development, etching, and photoresist removal are performed.

  In the exposure and drawing processes, it is possible to form a pattern on both sides of the substrate. For example, a drawing device is provided with a mechanism for turning the substrate upside down so that the pattern is continuously formed on both sides of the substrate. Further, when forming a pattern hierarchically on the substrate, different patterns are drawn in multiple times and the patterns are superimposed.

  In a drawing apparatus, in order to form a pattern accurately at a predetermined position on a substrate, it is required to accurately adjust alignment. However, when the substrate itself is deformed due to heat treatment or the like, the pattern position is shifted. Therefore, for example, alignment marks for positioning are provided at the four corners of the drawing area, and the displacement of the alignment mark is detected by a CCD camera. The drawing data is corrected from the measured positional deviation amount, and the pattern formation position is adjusted (see, for example, Patent Documents 1 and 2).

  On the other hand, the alignment mark for positioning can be used to detect the orientation and front / back of the substrate. In the manufacturing process, there are many operations in which a sample substrate is randomly extracted from the process for quality inspection and returned again after the inspection. For this reason, the substrate is carried into the drawing apparatus with the orientation and front / back of the substrate being incorrect. In particular, when the same alignment mark is provided on both sides of the substrate, it is easy to confuse the front and back.

In order to prevent such a substrate mounting error, a method is known in which one of the alignment marks provided at the four corners is different in size, shape, pattern, etc. from the alignment mark (Patent Document 3). reference). In this case, the position of an alignment mark different from the other is detected, and it is determined whether the alignment mark position corresponds to an expected appropriate position. If the detected alignment mark position is at a different position, it is determined that the orientation of the substrate or the front and back are incorrect, and the drawing process is not performed.
JP-A-2005-300628 JP 2000-122303 A JP 2005-10702 A

  Recent exposure and drawing apparatuses require mass production by improving throughput while forming a pattern with high accuracy. Therefore, restrictions are imposed on the setting position and size of the alignment mark in accordance with the improvement of the pattern accuracy, and it is difficult to detect the position of the alignment mark and determine the front and back with the conventional method. In addition, it is necessary to perform the alignment mark setting process performed before the exposure and drawing processes as efficiently as possible.

  The exposure system of the present invention is an exposure system including a maskless drawing apparatus or an exposure apparatus using a mask, and can form a pattern on a drawing object such as a substrate. The object to be drawn is formed with a plurality of marks having different setting positions on both sides and mounted on the table at the time of exposure. Here, a plurality of marks provided on each surface include holes, and for example, alignment marks for positioning are applied. Here, “the setting position is different” means that the position from the reference point is different for at least one mark when the objects to be drawn are reversed. When the object to be drawn is mounted on the table, one of the surfaces becomes the exposure target surface, that is, the surface, and the other surface becomes the bottom surface facing the drawing table.

  An exposure system according to the present invention includes a mark position detection unit that detects the position of a mark on an exposure target surface of a drawing object mounted on a table, and a first preset on one of the two surfaces (first surface). Based on the position displacement of the mark relative to the position of the 1 reference mark and the position displacement of the mark relative to the position of the second reference mark preset on the other surface (second surface), Determining means for determining whether the exposure target surface is the first surface or the second surface.

  The first reference mark is a design mark preset as data. If there is no substrate deformation or the like, the position of the reference mark coincides with the position of the measured mark. The second reference mark is a mark that serves as a design reference for the second surface.

  For example, when the first surface is the exposure target surface, an error (positional deviation) between the design reference mark position corresponding to the first surface and the measured mark position is only caused by substrate deformation or the like. And the error is not so big. On the other hand, with respect to the first reference mark on the first surface, the misalignment between the second reference mark and the measurement mark having different mark positions is not limited to the deformation of the substrate, but is set at a place different from the original position. Therefore, it can be considered that the error becomes larger than the error of the first surface.

  In the present invention, the surface to be exposed is determined from the degree of positional deviation between the reference marks on both the first and second surfaces and the actually measured marks. Therefore, when a substrate or the like is inverted by mistake, the error can be automatically detected based only on the measurement position of the mark having the same shape.

  For example, when there is a deviation in the mark position, an error occurs in the mark interval. The determination means may determine the exposure target surface based on the mark interval error. The number of marks is arbitrary, but considering that the degree of displacement of the entire pattern surface is detected, the first and second reference marks are composed of at least three reference marks, and the mark position detecting means It is sufficient to detect the positions of at least three marks. When the positional deviation is large only at one mark, the deviation of the three mark interval coupling lines measured with the mark position as the center is large, and determination is easy.

  When it is determined which surface is to be exposed, it is desirable to perform exposure processing in accordance with the surface to be exposed. Therefore, it is preferable that the exposure unit of the exposure system selects the pattern corresponding to the exposure target surface and executes the exposure process. In this case, a drawing pattern suitable for the exposure target surface is formed regardless of the mounting of the substrate or the like.

  For example, a memory for storing drawing data corresponding to the first surface and a memory for storing drawing data corresponding to the second surface are provided, and one of the drawing data is extracted after determining the exposure target surface. That's fine. In particular, in the case of an exposure system that includes a reversing mechanism and can continuously perform drawing processing on the first surface and the second surface, any surface of the drawing object may be carried as an exposure target surface. Appropriate drawing patterns are formed on both sides.

  When the substrate deformation is large and the positional deviation of each mark is large, it may be difficult to make a judgment simply by comparing the degree of positional deviation of the measured mark position. On the other hand, when the drawing data is corrected, the correction coefficient can be calculated based on the measured position coordinates of the mark and the reference mark. Therefore, it is desirable to make a front / back determination using the correction coefficient used in the drawing data correction process.

  Therefore, the determination unit is based on a comparison between the correction position of the first reference alignment mark obtained from the correction coefficient of the drawing data relating to the first surface and the correction position of the second reference alignment mark obtained from the correction coefficient relating to the second surface. Thus, it is preferable to determine the exposure target surface.

  For example, the determination unit may determine the exposure target surface based on a comparison of mark interval errors between the correction positions of the first and second reference alignment marks and the alignment mark position. Further, in order to correct the alignment mark position based on the correction scale amount, the first and second alignment marks of the first and second alignment marks are determined according to the correction scale amount with respect to the distance interval from the center position of the pattern to the correction positions of the first and second reference alignment marks. The correction position may be calculated.

  An exposure system program according to the present invention includes a mark position detection unit that detects a position of a mark on an exposure target surface with respect to a drawing object that is mounted on a table and has marks with different setting positions formed on both sides, and a first one. Based on the positional deviation of the mark based on the position of the first reference mark preset on the surface and the positional deviation of the mark based on the position of the second reference mark preset on the other second surface, A determination means for determining whether the exposure target surface of the drawing object is the first surface or the second surface is made to function.

  In the exposure method of the present invention, the position of the mark on the exposure target surface is detected in advance for a base material that is mounted on a table and has a plurality of marks with different setting positions formed on both surfaces, and is preset on one of the first surfaces. Based on the positional deviation of the mark with respect to the position of the first reference mark and the positional deviation of the mark with reference to the second reference mark set in advance on the other second surface, the exposure target surface of the drawing object is It is characterized by determining whether it is the 1st surface or the 2nd surface.

  According to the present invention, a pattern suitable for an exposure target surface can be reliably formed on a substrate or the like without reducing the throughput.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically illustrating a drawing system according to the present embodiment.

  The drawing system 10 can form a circuit pattern by irradiating light onto a substrate SW on which a photosensitive material such as a photoresist is formed, and can continuously form the pattern on both sides of the substrate being conveyed. The drawing system 10 includes a first exposure machine 20 and a second exposure machine 40. The first exposure machine 20 is on the upstream side (inlet side for substrate carry-in), and the second exposure machine 40 is on the downstream side (substrate outlet). Side).

  The rectangular substrate SW is a substrate for an electronic circuit such as a silicon wafer, a dry film, or a glass substrate, for example, and is in a blank state that has been subjected to processing such as pre-baking processing or photoresist coating, and the first exposure machine 20. Are mounted on the drawing table 22. Here, the exposure target surface that is the front side when the substrate SW is carried into the drawing system 10 from the outside is defined as the first surface OS.

  The substrate SW is provided with four circular alignment marks (alignment holes) AM0 to AM3 at the four corners of the drawing pattern region. In the first exposure machine 20, a pair of CCD cameras 24A, 24B are installed vertically above the drawing table 22 at predetermined intervals. The CCD cameras 24A, 24B are aligned with the alignment marks AM0, AM1 (AM2, AM3) of the substrate SW. The distance is separated according to the distance.

  The drawing data is stored in advance as CAD / CAM data in the external data server 80, and the drawing data is sequentially transmitted to the first exposure device 20 and the second exposure device 40. When the relative position of the alignment marks AM0 to AM3 with respect to the drawing table 22 is detected by the movement of the drawing table 22, the drawing data of the first surface OS is corrected according to the deformation state of the substrate SW. Based on the corrected drawing data, a drawing process is executed for the first surface OS.

  When the drawing process for the entire first surface OS is completed, the substrate SW is sent to the reversing mechanism 60. The reversing mechanism 60 reverses the front and back surfaces of the substrate SW, whereby the back side surface (hereinafter referred to as the second surface) US becomes the exposure target surface. The inverted substrate SW is mounted on the drawing table 42 of the second exposure machine 40.

  Also on the second surface US of the substrate SW, alignment marks BM0 to BM3 are provided at the four corners of the drawing pattern. The alignment marks AM0 to AM3 on the first surface OS and the alignment marks BM0 to BM3 on the second surface US are different in the installation positions of the alignment marks. Specifically, the mark position is set so that the graphic shape having the alignment mark as a vertex is different between the first surface OS and the second surface US.

  When the relative positions of the alignment marks BM0 to BM3 are detected by the pair of CCD cameras 44A and 44B provided in the second exposure device 40, the drawing data corresponding to the second surface US is corrected. A drawing process is executed based on the corrected drawing data. When the drawing process is completed for the entire second surface US, the substrate SW is transferred to the next apparatus.

  FIG. 2 is a block diagram of the drawing system 10.

  The first exposure machine 20 includes a plurality of DMDs (Digital Micro-mirror Devices) 21 in which micromirrors are arranged in a matrix as light modulation elements. Each DMD is mounted inside an exposure head (not shown) together with an illumination optical system and an imaging optical system, and spatially modulates illumination light from a light source via the illumination optical system. Each micromirror is independently controlled to be turned on / off, whereby a light beam corresponding to the drawing pattern is irradiated onto the substrate SW. The exposure heads are arranged at equal intervals along the sub-scanning direction, and drawing processing by the DMD 21 is performed while the substrate SW relatively moves along the scanning direction.

  The system control circuit 30 controls the operation of the first exposure unit 20 and outputs control signals to circuits such as the drawing table control circuit 35, the read address control circuit 36, and the DMD drive circuit 38. The system control circuit 30 is connected to an external data server 80, and draws drawing data of the first surface OS of the substrate SW and drawing data of the second surface US on the opposite side thereof, respectively, in the first memory 29A and the second memory. Store in 29B. A program for controlling the drawing process is stored in advance in a ROM (not shown) in the system control circuit 30.

  The pattern data sent as CAD / CAM data from the data server 80 is vector data represented by coordinate data, and the system control circuit 30 normally reads the pattern data of the first surface OS stored in the first memory 29A. . The raster conversion circuit 32 converts the vector data into raster data that is image data for drawing. The raster data is two-dimensional dot pattern data of a circuit pattern represented by binary data of 1 or 0, and determines the position of each micromirror to be in an ON state or an OFF state.

  The raster data sequentially generated in accordance with the drawing process is temporarily stored in the buffer memory 34 and sent to the DMD driving circuit 38. The DMD drive circuit 38 includes a bitmap memory for storing raster data, and outputs the raster data as a control signal (drawing signal) to each DMD micromirror. The timing for reading raster data and writing to the DMD drive circuit 38 is controlled by a read address control circuit 36.

  The drawing table control circuit 35 outputs a control signal to the drive circuit 37 and controls the movement of the stage mechanism 39. The stage mechanism 39 can rotate the drawing table 22 while moving the drawing table 22 in the scanning and sub-scanning directions (XY directions). The position detection sensor 33 detects the relative position of the substrate SW by detecting the position of the drawing table 22. The system control circuit 30 controls the DMD drive circuit 34, the read address control circuit 37, and the like based on the relative position of the substrate SW detected via the drawing table control circuit 35.

  When raster data corresponding to the exposure target area is input to the DMD driving circuit 38, a control signal for controlling each micromirror is output in synchronization with a clock pulse signal for matching the drawing timing. Thereby, the micromirror of each DMD is ON / OFF controlled based on the corresponding drawing signal. Here, the step & repeat method or the continuous movement method is applied as the exposure method.

  The alignment adjustment will be described. When the substrate SW is placed on the drawing table 22, the drawing table 22 is moved in the scanning direction. As a result, the CCDs 24A and 24B photograph the alignment marks AM0 to AM3 formed on the exposure target surface of the substrate SW, that is, the first surface OS. The mark position detection unit 26 outputs an image signal of the captured image, and the system control circuit 30 calculates (center) position coordinates of the alignment marks AM0 to AM3 based on the image signal.

  The system control circuit 30 sends drawing data based on the position coordinate information of the alignment marks sent from the data server 80 and temporarily stored in the memory 29A and the actually measured position coordinates of the alignment marks AM0 to AM3. Correct (vector data). Then, the corrected drawing data is output to the raster conversion circuit 32.

  The reversal control unit 62 drives the reversing mechanism 60 when it detects the end of the drawing process of the first exposure machine 20. As a result, the substrate SW is reversed and placed on the drawing table 49 of the second exposure device 40.

  Similar to the first exposure machine 20, the second exposure machine 40 includes a plurality of DMDs 41, and spatially modulates illumination light from the light source by controlling each micromirror on / off. The system control circuit 50 controls the drawing processing operation of the second exposure device 40 and outputs control signals to the read address control circuit 56, the drawing table control circuit 55, the DMD drive circuit 58, and the like.

  The drawing data for both the first surface OS and the second surface US is also transmitted from the data server 80 to the second exposure device 40 and stored in the first memory 49A and the second memory 49B, respectively. The drawing data corresponding to the second surface US is normally read out, converted into raster data by the raster conversion circuit 52, and stored in the buffer memory 54. The drawing process is executed by controlling the DMD micromirror based on the raster data read from the buffer memory 54.

  The drawing table control circuit 55 detects the position of the drawing table 49 from the position detection sensor 53, and outputs a control signal to the drive circuit 57 that drives the stage mechanism 59. Further, the position coordinates of the alignment marks BM0 to BM3 are detected based on the image data of the CCDs 44A and 44B obtained by the alignment mark position detection unit 46. Similar to the first exposure machine 40, the drawing data is corrected based on the position coordinates of the alignment marks BM0 to BM3.

  FIG. 3 is a diagram showing alignment marks on both sides of the substrate.

  As described above, in the present embodiment, the alignment marks AM0 to AM3 and BM0 to BM3 having different alignment mark positions are formed on the first surface OS and the second surface US, respectively. As shown in FIG. 3, rectangles having apexes of circular alignment marks AM0 to AM3 and BM0 to BM3 are trapezoidal shapes, and the alignment marks BM0 to BM3 invert the trapezoidal shapes of the alignment marks AM0 to AM3. It has a shape. However, the alignment mark position when the substrate is not deformed is shown here.

  In the substrate manufacturing process, a specific substrate may be extracted by inspection or the like and returned to the manufacturing process. If the substrate is turned upside down at this time, the surface that should originally be the exposure target surface is reversed. Therefore, when it is carried into the first exposure machine 20 of the drawing system 10, there occurs a situation where the first surface OS becomes the exposure target surface and the second surface OS becomes the upper surface.

  Since the position coordinates of the alignment marks AM0 and BM0 and the alignment marks AM3 and BM3 are greatly different from the reference point, if the deviation from the position coordinates of the reference alignment mark stored in advance as design data is large, the front and back are reversed. It can be considered that the substrate SW is installed.

  On the other hand, the drawing data is corrected by a correction coefficient calculated based on the alignment mark position. Therefore, when the alignment mark position determined in design by the correction coefficient is corrected, if the error from the measured alignment mark position is small, it is determined that the front and back are not in error, and the front and back are determined. This will be specifically described below.

  FIG. 4 is a flowchart showing a drawing process including board front / back determination executed by the system control circuit 30. Here, an index relating to the alignment mark position deviation when it is assumed that the first surface is the exposure target surface, and an index relating to the alignment mark position deviation when it is assumed that the second surface is the exposure target surface Are compared to determine the front and back. Then, the drawing process is executed according to the drawing data of the exposure target surface.

  In step S101, the position information of the reference alignment marks on both the first surface OS and the second surface US of the substrate SW is acquired from the data server 80.

  FIG. 5 is a diagram showing a reference alignment mark for the first surface OS. Data of the position coordinates (DXn, DYn (n = 0 to 3)) of the four alignment marks DM0 to DM3 is read from the first memory 29A. However, the center position of the circular alignment marks DM0 to DM3 is defined as the alignment mark position coordinates. Further, one end O of the substrate SW is set as a coordinate origin.

  In step S102, the drawing table 22 moves while the substrate SW is mounted on the drawing table 22, and the alignment marks formed on the exposure target surface of the substrate SW are photographed by the CCD cameras 24A and 24B of the first exposure machine 20. To do. Hereinafter, the alignment marks formed on the exposure target surface which is the first surface OS or the second surface US are represented by MM0 to MM3.

  FIG. 6 is a diagram showing the positions of the measured alignment marks MM0 to MM3. As shown in FIG. 6, the position of the design reference alignment marks DM <b> 0 to DM <b> 3 is displaced due to thermal deformation of the substrate SW. In step S103, the position coordinates (MXn, MYn (n = 0 to 3)) of the alignment marks MM0 to MM3 are detected based on the image data of the alignment marks MM0 to MM3. Here, the center position is detected as the mark position.

  In step S104, the distance interval MLnm between the alignment marks is calculated from the detected position coordinates (MXn, MYn) by the following equation. That is, six alignment mark intervals ML01, ML12, ML23, ML30, ML13, and ML02 are obtained.

  On the other hand, in step S105, based on the position coordinates (DXn, DYn) of the reference alignment marks DM0 to DM3 obtained in step S101, the DLnm between alignment marks on the design data (in an ideal state without substrate deformation) is expressed by the following equation. Sought by. That is, six alignment mark intervals DL01, DL12, DL23, DL30, DL13, and DL02 are calculated.

  In step S106, correction scale amounts SCX and SCY for correcting the drawing data are calculated by the following equations. SCX represents a correction scale amount along the X direction (scanning direction), and SCY represents a correction scale amount in the Y direction (sub-scanning direction).

As shown in the equation (3), the correction scale amounts SCX and SCY indicate the enlargement / reduction ratio of the graphic on the bisector along the X direction and the Y direction passing through the pattern center (graphic center). In other words, it represents the average similarity ratio (scale ratio) in the X and Y directions between the figure having the reference alignment marks DM0 to DM3 as vertices and the figure having the measured alignment marks MM0 to MM3 as vertices.

  In step S107, the positions of the reference alignment marks DM0 to DM3 are corrected based on the correction scale amount. The position coordinates (Sxn, Syn (n = 0 to 3)) of the corrected alignment marks SM0 to SM3 are obtained by the following equations. However, (CX, CY) represents the center position coordinate of the pattern area and is the center position of the drawing pattern formation. The position coordinates of the drawing pattern data are corrected based on this center position.

  FIG. 7 is a diagram showing the positions of the correction alignment marks SM0 to SM3. As shown in the equation (3), the positions of the correction alignment marks SM0 to SM3 are obtained by multiplying the distance from the pattern center position to the reference alignment marks DM0 to DM3 by the correction scale. When the figure having the reference alignment marks DM0 to DM3 as vertices is enlarged (reduced) as a whole by the scale ratio (similarity ratio), the vertices of the figures become the positions of the correction alignment marks SM0 to SM3.

  In step S108, based on the position coordinates calculated in step S107, (Sxn, Syn), the mark interval SLnm of the corrected alignment marks SM0 to SM3 is obtained by the following equation. Thereby, six mark intervals SL01, SL12, SL23, SL30, SL13, and SL02 are calculated.

  In step S109, an index St representing a difference between the mark interval SLnm of the corrected alignment marks SM0 to SM3 and the measured alignment mark MLnm is obtained by the following equation. The indicator St indicates six mark interval errors | ML01-SL01 |, | ML12-SL12 |, | ML23-SL23 |, | ML30-SL30 |, | ML02-SL02 |, Represents the average value of | ML31-SL13 |. The closer the corrected alignment marks SM0 to SM3 are to the actually measured alignment marks MM0 to MM3, the smaller the value of the index St.

  When the indexes St of the reference alignment marks DM0 to DM3 on the first surface OS are obtained in steps S101 to S109, the index Sb based on the reference alignment marks DM′0 to DM′3 on the second surface US is determined in step S110. .

  FIG. 8 is a diagram illustrating the reference alignment marks DM′0 to DM′3 on the second surface US. When the position coordinate data of the reference alignment marks DM′0 to DM′3 is read from the second memory 29B, the index Sb is obtained by the following equation, as with the first surface OS. Here, ML′nm represents the measured distance between the alignment marks, and SL′nm represents the distance between the corrected alignment marks according to the obtained correction scale amount.

  In step S111, the index St of the first surface OS and the index Sb of the second surface US are compared. When the index St <Sb, it can be considered that the positions of the corrected alignment marks SM0 to SM3 when the first surface OS is the exposure target surface are closer to the positions of the measured alignment marks MM0 to MM3. That is, the positions of the alignment marks MM0 to MM3 are less misaligned with respect to the reference alignment marks DM0 to DM3 on the first surface OS than the reference alignment marks DM′0 to DM′3 on the second surface US, and the first surface It is determined that the OS is the exposure target surface.

  On the other hand, when the index St> Sb, the actual position of the alignment marks MM0 to MM3 can be regarded as close to the position of the reference alignment marks DM′0 to DM ″ 3 of the second surface US. Is determined to be the exposure target surface.

  Therefore, if St <Sb, the drawing data corresponding to the first surface OS is read from the first memory 29A, and if St> Sb, the drawing data corresponding to the second surface US is read from the second memory 29B.

  The front / back determination can also be performed by detecting the positions of the three alignment marks without detecting all the four alignment marks. For example, when the alignment mark MM0 is not detected, an average value of ML1, ML23, and ML31 and an average value of SL12, SL23, and S311 may be calculated.

  In step S112, in addition to the previously calculated correction scale amounts SCX and SCY, offset amounts OFFX and OFFY, which are further correction coefficients for alignment, and a rotation amount Th are calculated. However, the offset amounts OFFX and OFFY represent the offset amounts in the X and Y directions, respectively, and the rotation amount Th is the reference alignment marks DM0 to DM3 (or DM′0 to DM) based on the pattern center coordinates (CX, XY). '3) represents the rotation angle. In the case of the drawing data of the first surface OS, the offset amount and the rotation amount are obtained by the following equations.

  In step S113, the drawing pattern data of the vector data is corrected based on the correction scale amount, the offset amount, and the rotation amount. In the case of vector data, since the position coordinates of the start point and end position of the pattern are provided as drawing data, the drawing data is corrected based on the correction scale amount, the offset amount, and the rotation amount. In step S114, a drawing process is executed based on the corrected drawing data.

  Note that the offset and rotation alignment may be configured such that the drawing table 22 is shifted and rotated by the stage mechanism 39 instead of correcting the drawing data.

  When the drawing process in the first exposure machine 20 is completed, the drawing process in the second exposure machine 40 is executed. Similar to the first exposure machine 20, the same front / back determination and drawing processing as those in steps S101 to S113 in FIG. 4 are executed. Since the first exposure machine 20 has already determined the front and back, the information is received from the system control circuit 30 of the first exposure machine 20, and the drawing data of the exposure target surface is read based on the information, A drawing process may be performed.

  Further, in step S110 in FIG. 4, the average alignment mark interval error between the reference alignment mark and the measured alignment mark is calculated. The error of each alignment mark interval is calculated individually, and the surface where the maximum error exists is calculated. You may comprise so that a reverse surface may be judged as an exposure object surface.

  For example, six alignment mark interval errors when the first surface OS is the reference are DTnm = | MLnm−SLnm |, and alignment mark interval errors when the second surface is the reference are DT′nm = | MLnm−. SLnm |. The maximum error among the six DTnms is defined as DTmax, and the maximum error among the six DT'nms is defined as DT'max. If DTmax <DT′max, it is determined that the first surface OS with a small maximum error is the exposure target surface, and if DTmax <DT′max, the second surface is determined to be the exposure target surface.

  As described above, according to the present embodiment, when the substrate SW is carried into the drawing system 10, the positions of the alignment marks MM0 to MM3 formed on the exposure target surface are detected by the CCD cameras 22A and 22B. Then, the correction scale amounts SCX and SCY are calculated from the error amount of the mark interval between the reference alignment marks DM0 to DM3 and the alignment marks MM0 to MM3 on the first surface OS, and the correction alignment marks SM0 to SM3 are calculated.

  Then, an index St that is an average difference between the mark interval SLnm of the corrected alignment marks SM0 to SM3 and the mark interval MLnm of the measured alignment marks MM0 to MM3 is calculated. Similarly, the index Sb is calculated for the second surface US. When the index St <Sb, it is determined that the first surface OS is the exposure target surface, and the drawing process is performed based on the drawing data of the first surface OS. That is, the degree of displacement of the measurement alignment marks MM0 to MM3 calculated with respect to the first surface is considered to be less than the degree of displacement calculated with respect to the second surface, and the exposure handling surface is the first surface. Judge that there is. Thus, in order to reliably determine the exposure target surface, even if the substrate is carried in by mistake, the appropriate pattern is formed on both the first surface OS and the second surface US.

  In the above description, the state in which the first surface OS becomes the exposure target surface in the first exposure machine 20 is determined to be normal. However, the drawing system 10 determines which of the first surface OS and the second surface US is first. However, the drawing process can be performed with appropriate drawing data. That is, the drawing system 10 can execute a drawing process based on drawing data suitable for the exposure target surface regardless of the front and back sides.

  For example, the indexes St and Sb of the first surface and the second surface are calculated for the substrate SW that is loaded first, and the Sb magnitude of St is compared. The exposure target surface of the substrate sequentially carried in from the next can be determined based on this size determination. Thereby, even if it carries in in the state where the board | substrate front and back were random, the suitable pattern can be formed in both surfaces.

  When the deformation of the substrate SW is large, not only the alignment marks DM0 and DM'3 that have a corresponding relationship in which the alignment mark positions differ greatly, but also the positions of other alignment marks are shifted. However, since the alignment mark interval error is compared and determined based on the positions of the corrected alignment marks SM0 to SM3, it is possible to reliably determine the front and back.

  The number of alignment marks is not limited to four, and at least three alignment marks may be used so as to appear as an alignment mark interval error. Alternatively, it may be constituted by two alignment marks, and the front / back determination may be made by a mark interval error in one direction. The shape and type of the alignment mark can be set to other than a circular shape. A dedicated mark may be set separately from the positioning mark for drawing data correction. The setting position of the mark position may be other than the trapezoidal vertex position described above, and it may be configured such that all mark position coordinates do not coincide when the front and back are reversed.

  The exposure target surface may be determined by a method other than the above-described total average of mark interval errors or the comparison of maximum errors. Further, the correction position of the reference alignment mark may be calculated without using the pattern center position as a reference, and may be calculated using a correction coefficient other than the correction scale amount. Further, instead of the mark distance interval, the front / back determination may be performed based on the positional deviation in the position coordinates of each mark.

  If the conditions are such that substrate deformation does not occur so much, the correction position of the reference alignment mark is not calculated, the mark interval error between the reference alignment mark and the measured alignment mark is directly calculated, and the degree of positional deviation is directly compared to determine the front and back May be.

  In the present embodiment, a drawing system is provided in which an appropriate pattern is formed on both sides of the substrate even if the front and back are reversed. However, a drawing system that performs drawing processing on only one side may be used. In this case, if the front and back are incorrect, the drawing process may be configured not to be performed. In addition to the drawing system, the present invention may be applied to an exposure apparatus that uses a mask (reticle) such as a stepper, or a system that performs pattern formation by other exposure.

It is the figure which showed roughly the drawing system which is this embodiment. It is a block diagram of a drawing system. It is the figure which showed the alignment mark of both surfaces of a board | substrate. It is a flowchart which shows the drawing process including the board | substrate front / back determination performed by a system control circuit. It is the figure which showed the reference | standard alignment mark with respect to a 1st surface. It is the figure which showed the position of the alignment mark measured. It is the figure which showed the position of the correction alignment mark. It is the figure which showed the reference | standard alignment mark of 2nd surface US.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drawing system 20 1st exposure machine 22 Drawing table 30 System control circuit 40 2nd exposure machine SW Substrate (object to be drawn)
OS 1st surface US 2nd surface MM0 to MM3 Alignment mark DM0 to DM3 Reference alignment mark (reference mark)
SM0 to SM3 Correction alignment mark

Claims (10)

Mark position detecting means for detecting the position of the mark on the exposure target surface for the drawing object mounted on the table and having the marks with different setting positions formed on both sides;
The positional deviation of the mark with reference to the position of the first reference mark preset on one first surface and the position of the mark with reference to the position of the second reference mark preset on the other second surface An exposure system comprising: a determination unit that determines whether the exposure target surface of the drawing object is the first surface or the second surface based on a positional deviation.   The exposure system according to claim 1, further comprising an exposure unit that selects a pattern according to an exposure target surface and executes an exposure process.   The exposure system according to claim 1, wherein the determination unit determines an exposure target surface based on a mark interval error. Based on a correction coefficient obtained from the amount of misalignment of the alignment mark, further has a data correction amount calculation means for calculating the correction amount of the drawing data,
Based on the correction position of the first reference alignment mark obtained from the correction coefficient of the drawing data relating to the first surface and the correction position of the second reference alignment mark obtained from the correction coefficient relating to the second surface. The exposure system according to claim 1, wherein an exposure target surface is determined.   The mark position detection unit determines an exposure target surface based on a comparison of mark interval errors between the correction positions of the first and second reference alignment marks and the measured position of the alignment mark. The exposure system according to claim 4.   The determination means calculates the correction positions of the first and second reference alignment marks based on the correction scale amount with respect to the distance interval from the center position of the drawing pattern to the correction positions of the first and second reference alignment marks. The exposure system according to claim 4, wherein The first and second reference marks comprise at least three reference marks;
3. The exposure system according to claim 1, wherein the determination unit detects positions of at least three corresponding marks.   The exposure system according to claim 2, wherein the exposure unit is capable of continuously performing a drawing process on the first surface and the second surface. Mark position detecting means for detecting the position of the mark on the exposure target surface for the drawing object mounted on the table and having the marks with different setting positions formed on both sides;
The positional deviation of the mark with reference to the position of the first reference mark preset on one first surface and the position of the mark with reference to the position of the second reference mark preset on the other second surface A program for an exposure system, which causes a determination unit that determines whether an exposure target surface of the drawing object is the first surface or the second surface based on a positional deviation. The position of the mark on the exposure target surface is detected on the base material that is mounted on the table and has multiple marks with different setting positions formed on both sides.
Misalignment of the mark based on the position of the first reference mark preset on one first surface, and Misalignment of the mark based on the second reference mark preset on the other second surface And determining whether the surface to be exposed of the drawing object is the first surface or the second surface based on the above.

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