JP2015012258A - Exposure equipment, exposure method, and method for manufacturing device by using the equipment and the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide exposure equipment advantageous to improvement in overlay accuracy in a joint region when performing joint exposure.SOLUTION: The exposure equipment joints a first image with a second image to expose an image having an area larger than that of the first image or the second image to a pattern forming region PS10 on a substrate. Further, the exposure equipment has a control unit for allowing one or more alignment marks AM12, AM13 (AM21, AM22) in a scanning direction of the substrate to be formed in a joint region C in which a first pattern region MS1 for formation of the first image and a second pattern region MS2 for formation of the second image are overlapped with each other in the pattern forming region PS10, and allowing alignment in forming the next layer on the image by using the alignment marks AM12, AM13 (AM21, AM22).

Description

  The present invention relates to an exposure apparatus, an exposure method, and a device manufacturing method using them.

  In a lithography process, which is one of the manufacturing processes for liquid crystal display devices and the like, an exposure apparatus applies a pattern of a mask (original plate) to a photosensitive plate (such as a glass plate having a resist layer formed on the surface) through a projection optical system. A substrate). In recent years, in order to cope with an increase in area of one pattern formation region accompanying an increase in the size of the plate, the pattern formation region on the plate is divided into a plurality of shot regions, and a pattern image corresponding to each shot region is sequentially exposed. There is a stitching exposure type exposure apparatus. In such an exposure apparatus, so-called joint exposure is performed in which a part of the pattern of adjacent shot regions is joined and exposed. Here, there is a first pattern formed in the first shot region using the first mask and a second pattern formed in the second shot region adjacent to the first shot region. Assume that. Then, consider a case where an image of a pattern of the first mask or a second mask different from the first mask is further exposed (overlapping the next layer) on these patterns. In this case, Patent Document 1 detects in advance the position of the alignment mark image exposed to the first shot area, performs alignment with the mask based on the detection result, An exposure method for performing exposure on a shot area is disclosed.

JP-A-6-204105

  However, in the exposure method shown in Patent Document 1, when exposure is performed on an adjacent shot area, an image of an alignment mark as a latent image pattern of the shot area that has already been exposed is detected. In addition, alignment marks used for alignment are only those that exist in areas other than the area where the connection exposure is performed (the connection area). Therefore, the overlay accuracy is not guaranteed in the connection area.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide an exposure apparatus that is advantageous for improving overlay accuracy in a joint region when performing joint exposure, for example.

  In order to solve the above problems, the present invention connects a first image and a second image to form an image having a larger area than the first image or the second image in a pattern formation region on the substrate. An exposure apparatus that exposes a substrate in a connection region where a first pattern region for forming a first image and a second pattern region for forming a second image overlap each other in the pattern formation region And a control unit that performs alignment when forming one or more alignment marks in the scanning direction and forming the next layer on the image using the alignment marks.

  According to the present invention, it is possible to provide an exposure apparatus that is advantageous for improving the overlay accuracy in a joint area when performing joint exposure, for example.

It is a figure which shows the structure of the exposure apparatus which concerns on one Embodiment of this invention. It is a figure which shows arrangement | positioning of the alignment mark in one Embodiment. It is a flowchart which shows the flow of exposure with respect to the next layer in one Embodiment. It is a figure explaining calculation of the amount of correction in one embodiment. It is a figure explaining the operation | movement at the time of connection exposure in one Embodiment. It is a figure which shows the ideal illumination intensity distribution of the connection area | region in one Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  First, the configuration of an exposure apparatus according to an embodiment of the present invention will be described. FIG. 1 is a schematic view showing the arrangement of an exposure apparatus 10 according to this embodiment. The exposure apparatus 10 shall be employ | adopted as the lithography process in the manufacturing process of a liquid crystal display device (liquid crystal panel) as an example. The exposure apparatus 10 is a plate (glass) that is a substrate having a resist (photosensitive agent) layer formed on the surface of a pattern formed on a mask M via a projection optical system 105 by a step-and-scan method. It is a scanning projection exposure apparatus that exposes on a plate (P) (on a substrate). In FIG. 1, the Y axis is taken in the scanning direction of the mask M and the plate P during exposure in the plane perpendicular to the Z axis, which is the vertical direction, and the X axis is taken in the non-scanning direction orthogonal to the Y axis. . The “optical system” used in the description refers to a system composed of one or a plurality of mirror bodies and / or lens bodies. The exposure apparatus 10 includes an illumination system 100, a mask stage 106, a projection optical system 105, a plate stage 107, and a control unit 200.

  The illumination system 100 receives light emitted from a light source 108 such as an Hg lamp and irradiates the mask M with illumination light shaped like a slit. The illumination system 100 includes, for example, a fly-eye optical system 101, a reflecting mirror 102, a shutter optical system 103, a light shielding mechanism 109, and an imaging optical system 104. The illumination light F collected by the elliptical mirror of the light source 108 is adjusted to a light flux having a uniform illuminance distribution by the fly-eye optical system 101, then reflected by the reflecting mirror 102 and incident on the shutter optical system 103. . The shutter optical system 103 includes a slit 103a (see FIG. 5) that defines an exposure area. The illumination light F that has passed through the shutter optical system 103 enters the light shielding mechanism 109. The light shielding mechanism 109 includes a light shielding plate (light shielding member) 109a and a light shielding control unit 201 that controls the movement operation of the light shielding plate 109a. The light shielding plate 109a is arranged at a position conjugate with the position of the mask M at the time of exposure, and is illuminated by moving at least in the scanning direction of the mask M and the plate P at the time of exposure, that is, the + side and the − side in the Y axis direction. The light F can be shielded. With the movement of the light shielding plate 109a, the size of the opening through which the illumination light F passes (to the extent that it is blocked by the light shielding plate 109a) is defined, The light enters the imaging optical system 104 and forms an image on the mask M.

  The mask M is, for example, a glass original plate on which a fine pattern (for example, a circuit pattern) to be exposed is drawn. The mask stage 106 is movable at least in the Y-axis direction while holding the mask M by, for example, vacuum suction. The projection optical system 105 maintains a mask M and the plate P held by the plate stage 107 in an optically conjugate relationship, and projects a pattern image onto the plate P at an equal magnification. The plate stage 107 is movable at least in the Y-axis direction while holding the plate P by, for example, vacuum suction. Mask stage 106 and plate stage 107 are driven by stage control unit 202.

  The control unit 200 can control the operation and adjustment of each component of the exposure apparatus 10. The control unit 200 is configured by, for example, a computer, is connected to each component of the exposure apparatus 10 via a line, and can control each component according to a program or the like. In particular, the control unit 200 in the present embodiment can include the light shielding control unit 201 and the stage control unit 202 described above. Note that the control unit 200 may be configured integrally with other parts of the exposure apparatus 10 (in a common casing), or separate from the other parts of the exposure apparatus 10 (in a separate casing). It may be configured. The light shielding control unit 201 and the stage control unit 202 may also be installed independently without being integrated with the control unit 200.

  Next, the processing operation of the exposure apparatus 10 will be described. The exposure apparatus 10 scans the mask M and the plate P synchronously, and exposes a pattern image existing in the illumination range of the mask M to a pattern formation region on the plate P. Here, the exposure apparatus 10 sets a plurality of shot areas per pattern forming area and exposes a part of the pattern image when exposing an area larger than the pattern image existing on the mask M to the pattern forming area. So-called continuous exposure is performed in which exposure is performed a plurality of times while overlapping each other. Hereinafter, a first shot area and a second shot area partially overlapping with the first shot area are set for one pattern formation area, and each image is formed in each shot area with one mask M. It will be described as a continuous exposure by exposing.

  FIG. 2 illustrates the arrangement of alignment mark patterns (mark patterns) M10 formed in advance on the mask M used in the present embodiment and the arrangement of alignment marks exposed on the pattern formation region PS10 on the plate P. It is a schematic plan view for doing. By using the mask M to expose pattern images in the first shot region PS1 (see FIG. 2E) and the second shot region PS2 (see FIG. 2F), the pattern formation region PS10 is exposed. Perform bridging exposure. For example, as shown in FIG. 2A, the mask M is formed with a first pattern region MS1 in which a pattern to be exposed in the first shot region PS1 is formed and a pattern in which the second shot region PS2 is exposed. Second pattern region MS2. In the mask M, for example, twelve mark patterns are arranged side by side along the Y axis that is the scanning direction. The mark pattern is formed on the side or corner of the pattern area formed on the mask M. In particular, in this example, six mark patterns are aligned in the X-axis direction + side, and the other six mark patterns are in the same row in the X-axis direction + side and in the Y-axis direction. Are arranged along. Such an arrangement is advantageous in that the formation area of a pattern (such as a circuit pattern to be transferred) formed on the mask M can be made as wide as possible, or deformation such as distortion of the mask M can be detected with high accuracy. It is. Further, four of the plurality of mark patterns formed on the mask M are arranged in the vicinity of the four vertices on the surface of the mask M which is a rectangle. In addition, four other mark patterns are arranged at equal intervals in the Y-axis direction in the central region of the two sides parallel to the Y-axis direction of the pattern area of the mask M, respectively.

  2B and 2C are diagrams in which the first pattern region MS1 and the second pattern region MS2 shown in FIG. 2A are individually extracted. First, as shown in FIG. 2B, the first pattern region MS1 includes the mark pattern M10 in the vicinity of two vertices in contact with one side surface parallel to the X axis, and the central region. This area includes a total of eight mark patterns. On the other hand, as shown in FIG. 2C, the second pattern region MS2 is in the vicinity of the two vertices in contact with the other side of the pattern region parallel to the X axis among the mark patterns M10. This is an area including a mark pattern and a total of eight mark patterns in the central area. That is, the first pattern region MS1 and the second pattern region MS2 share a total of eight mark patterns in the central region.

  FIG. 2D is a diagram showing the pattern formation region PS10 on the plate P and the arrangement of alignment marks exposed (formed) in the pattern formation region PS10 using the mask M. The pattern formation region PS10 includes a first shot region PS1 exposed using the first pattern region MS1 of the mask M and a second shot region PS2 exposed using the second pattern region MS2 of the mask M. Including. FIGS. 2E and 2F are diagrams in which the first shot region PS1 and the second shot region PS2 shown in FIG. 2D are extracted individually. First, using the first pattern region MS1 of the mask M, exposure is performed while synchronously scanning the mask M and the plate P in the Y-axis direction, and the first shot region PS1 shown in FIG. An image (first image) of one pattern region MS1 is transferred. Next, the mask M and the plate P are exposed while being synchronously scanned in the Y-axis direction, and an image (second image) of the second pattern region MS2 is formed in the second shot region PS2 shown in FIG. ) Is transcribed. As a result, a first layer including a connection region C where the first image and the second image overlap is formed in the pattern formation region PS10, and a plurality of layers based on the mark pattern M10 formed on the mask M are formed. The alignment mark is formed. Specifically, first, when the first image is exposed, as shown in FIG. 2E, five alignment marks AM11 to AM15 are formed in two rows along the side of the shot region parallel to the Y axis. The Next, when the second image is exposed, as shown in FIG. 2F, five alignment marks AM21 to AM25 are formed in two rows along the side of the shot region parallel to the Y axis. At this time, the two alignment marks AM21 and AM22 arranged in the Y-axis direction near the first shot region PS1 overlap with the alignment marks AM12 and AM13 that have already been formed in the connection region C, respectively, Become. That is, in the present embodiment, one or more alignment marks are formed not only in the connecting region C but also in the connecting region C in the Y-axis direction. However, when the correction amount is calculated using the alignment mark existing in the connection region C as described later, two or more alignment marks AM are formed in the Y-axis direction as shown in FIG. It is desirable that The alignment mark AM formed here is used for position detection when the next layer is formed (exposed) on the first layer (on the first and second images).

  FIG. 3 is a flowchart showing the flow of processing for detecting the alignment mark AM formed on the plate P as described above and forming the next layer by connecting exposure. First, as exposure for the next layer, the control unit 200 measures (detects) alignment marks AM11 to AM13 (indicated by broken-line circles in FIG. 2E) formed in the first shot region PS1 ( Step S101). Next, the control unit 200 determines whether or not the alignment marks AM11 to AM13 have been successfully measured in step S101 (step S102). Here, when the control unit 200 determines that the measurement has been successful (YES), next, the alignment marks AM21 to AM23 formed in the second shot region PS2 (broken lines in FIG. 2 (f)). (Indicated by a circle) is measured (step S103). On the other hand, when the control unit 200 determines in step S102 that the measurement has not been successful (NO), the process proceeds to step S104, and alignment marks (for example, alignment marks AM11, AM11, etc.) formed outside the connecting region C are transferred. AM14, AM15) are measured. Thereafter, the process proceeds to step S103. Next, in step S103, the control unit 200 determines whether or not the alignment marks AM21 to AM23 have been successfully measured (step S105). If the control unit 200 determines that the measurement is successful (YES), the control unit 200 then calculates a correction amount for each shot region based on the measured detection result of the alignment mark AM (step S107). . On the other hand, when the control unit 200 determines in step S105 that the measurement has not been successful (NO), the process proceeds to step S106, and alignment marks (for example, alignment mark AM23, AM24, AM25) are measured. Thereafter, the control unit 200 proceeds to step S107, and calculates a correction amount for each shot area based on the detection result of the measured alignment mark AM (in this case, AM23, AM24, AM25). Next, the control unit 200 sequentially scans the mask M and the plate P synchronously to perform exposure on the second shot region PS2 (step S108) and subsequent exposure on the first shot region PS1 (step S109), that is, The continuous exposure is performed, and the process is terminated. The correction at the time of exposure using the calculated correction amount will be described later.

  Next, the calculation of the correction amount in step S107 will be described. The correction amount herein includes, for example, an X-axis direction (direction orthogonal to the scanning direction) shift component, a Y-axis direction (scanning direction) shift component, an X magnification component (a magnification component in a direction orthogonal to the scanning direction), Y A magnification component (a magnification component in the scanning direction) or a rotation component is included. Hereinafter, as an example, a case where the correction amount (the amount to be corrected) is an X magnification component will be described.

  FIG. 4 is a schematic plan view showing the first shot region PS1 and the second shot region PS2 for explaining the calculation of the correction amount in step S107. In this example, the detection results AM11 ′, AM12 ′, AM13 ′ of the alignment marks AM11, AM12, AM13 existing in the first shot region PS1 are shifted from the ideal shot region (X magnification component = 0). (Including displacement). First, the X magnification component of the first shot region PS1 can be calculated from the average value MX of the detection results AM11 ', AM12', and AM13 '. Here, in order to give priority to the overlay accuracy of the connection area C, the control unit 200 calculates magnification residuals d1 and d2 in the connection area C based on the average value MX and the detection results AM12 ′ and AM13 ′ ( d1 = AM12′−MX, d2 = AM13′−MX). If the control unit 200 determines that any one of the magnification residuals d1 and d2 exceeds the allowable amount, the control unit 200 adds an amount obtained by adding the average value ((d1 + d2) / 2) of the magnification residuals to the average value MX. Here, the X magnification component (correction amount) is used. On the other hand, the X magnification component of the second shot region PS2 can be similarly calculated from the average value MX 'of the detection results AM21', AM22 ', AM23' of the alignment marks AM21, AM22, AM23. In this case, based on the average value MX ′ and the detection results AM21 ′ and AM22 ′, magnification residuals d3 and d4 in the connection region C are calculated (d3 = AM21′−MX ′, d4 = AM22′−MX ′). . When the control unit 200 determines that any one of the magnification residuals d3 and d4 exceeds the allowable amount, the control unit 200 adds the average magnification residual value ((d3 + d4) / 2) to the average value MX ′. Is the X magnification component here. The control unit 200 corrects the overlay error using these correction amounts, and performs connection exposure, thereby connecting the corrected first shot region T1 and the corrected second shot region T2. The overlay accuracy in C can be sufficiently maintained.

  The method for calculating the correction amount is not limited to the above. For example, the average value of all magnification residuals ((d1 + d2 + d3 + d4) / 4) is the average value MX ″ ((AM11 ′ + AM12 ′ + AM13 ′ + AM21 ′ + AM22 ′ + AM23 ′) / 6) of the detection results of all alignment marks AM. To the X magnification component. In this case, the calculated X magnification component is a correction amount common to the first shot area PS1 and the second shot area PS2.

  Next, synchronous scanning of each component of the exposure apparatus 10 when performing the above-described joint exposure will be described. In the joining exposure in the present embodiment, a part of the first shot area PS1 and a part of the second shot area PS2 overlap in the joining area C. Therefore, it is desirable to make the exposure amount uniform in the connecting region C and other regions, that is, to make the integrated illuminance reaching the plate P uniform. Therefore, the exposure apparatus 10 synchronously scans the light shielding mechanism 109 having the light shielding plate 109a, the mask stage 106 that holds the mask M, and the plate stage 107 that holds the plate P as follows, so that the integrated illuminance is increased. adjust.

  FIG. 5 is a schematic side view for explaining synchronous scanning of the light shielding mechanism 109, the mask stage 106, and the plate stage 107 at the time of joint exposure in the present embodiment. In particular, FIG. 5A shows a state when the connection area C is exposed immediately before the end of exposure (just before the end of the first exposure) for the first shot area PS1 in a certain pattern formation area PS10 on the plate P. FIG. In the joint exposure in the present embodiment, immediately before the end of the first exposure, the light shielding plate 109a of the light shielding mechanism 109 is synchronized with the movement (scanning) of the mask M and the plate P in the + Y axis direction in the −Y axis direction. Move (scan). By this synchronous scanning, the light transmission side of the aperture slit 103a is gradually shielded, and the amount of illumination light F passing through the aperture slit 103a is gradually reduced. The illumination light F with the light quantity adjusted in this way illuminates a part of the pattern area of the mask M, so that the image is exposed to the connecting area C of the pattern formation area PS10 on the plate P and the exposure amount is almost linear. Transfer is performed with an exposure amount distribution that is small.

  On the other hand, FIG. 5B is a diagram showing a state when the connection region C is exposed immediately after the exposure of the second shot region PS2 in the certain pattern formation region PS10 is started (immediately after the start of the second exposure). First, at the start of the second exposure in the joint exposure, the light transmission side of the opening slit 103a is blocked by the light shielding plate 109a. In this state, the joint area C is positioned in the exposure area. The light shielding plate 109a moves in the −Y axis direction in synchronization with the movement of the mask M and the plate P in the + Y axis direction. By this synchronous scanning, the light transmission side of the aperture slit 103a is gradually opened, and the amount of illumination light F passing through the aperture slit 103a is gradually increased. The illumination light F with the light quantity adjusted in this way illuminates a part of the pattern area of the mask M, so that the image is exposed to the connecting area C of the pattern formation area PS10 on the plate P and the exposure amount is almost linear. The image is transferred with an exposure amount distribution that increases in size.

  FIG. 6 is a graph showing an ideal change in illuminance when the connecting region C is exposed while performing the synchronous scanning of each component shown in FIG. In FIG. 6, the horizontal axis indicates coordinates in the scanning direction (Y-axis direction) on the plate P, and the vertical axis indicates illuminance applied to the pattern formation region PS10 on the plate P. The illuminance TI1 at the time of the first exposure decreases in the connecting region C with an inclination. On the other hand, the illuminance TI2 at the time of the second exposure increases in the connecting region C with an inclination. Therefore, in the joint area C, although the two exposures overlap, the integrated illuminance TI3 is equivalent to the illuminance TI1 or TI2 in the area other than the joint area C.

  Thus, the exposure apparatus 10 forms the alignment mark in the connection region C as described above when performing the connection exposure, and uses this alignment mark for alignment when forming the next layer. Therefore, it is possible to carry out the overlay in the connecting region C with high accuracy. Further, the exposure apparatus 10 moves the light shielding plate 109a of the light shielding mechanism 109 in synchronization with the scanning of the mask M and the plate P as described above, so that the two exposures are overlapped when the connection region C is exposed. In addition, the alignment mark can be suitably formed in the connecting region C.

  As described above, according to the present embodiment, it is possible to provide an exposure apparatus that is advantageous for improving the overlay accuracy in the joint region when performing joint exposure.

  In the present embodiment, as shown in FIGS. 2A to 2C, the first pattern region MS1 and the second pattern region MS2 are set on the same mask M, and overlapping alignment marks are set. It is arranged. However, the present invention is not limited to this, and alignment marks for each pattern region may be formed on two different masks.

(Device manufacturing method)
Next, a method for manufacturing a device (semiconductor device, liquid crystal display device, etc.) according to an embodiment of the present invention will be described. A semiconductor device is manufactured through a pre-process for producing an integrated circuit on a wafer and a post-process for completing an integrated circuit chip on the wafer produced in the pre-process as a product. The pre-process includes a step of exposing a wafer coated with a photosensitive agent using the above-described exposure apparatus, and a step of developing the wafer. The post-process includes an assembly process (dicing and bonding) and a packaging process (encapsulation). A liquid crystal display device is manufactured through a process of forming a transparent electrode. The step of forming the transparent electrode includes a step of applying a photosensitive agent to a glass substrate on which a transparent conductive film is deposited, a step of exposing the glass substrate on which the photosensitive agent is applied using the above-described exposure apparatus, and a glass substrate. The process of developing is included. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 10 Exposure apparatus 200 Control part AM Alignment mark C Connection area | region M Mask P Plate MS1 1st pattern area MS2 2nd pattern area PS10 Pattern formation area

Claims (8)

An exposure apparatus that joins a first image and a second image to expose a pattern formation region on a substrate to an image having a larger area than the first image or the second image,
A first pattern region for forming the first image and a second pattern region for forming the second image are connected to each other in the pattern formation region in a connecting region in the scanning direction of the substrate. An exposure apparatus comprising: a control unit that forms one or more alignment marks and performs alignment when forming a next layer on the image using the alignment marks.   The first pattern area and the second pattern area including a mark pattern that forms the alignment mark when the first image and the second image are exposed to the pattern formation area. The exposure apparatus according to claim 1, wherein an original plate having the following is used.   3. The exposure apparatus according to claim 2, wherein the first pattern area and the second pattern area are in the same original plate and share the mark pattern. Two or more alignment marks are formed in the connecting region in the scanning direction,
The control unit obtains a correction amount by giving priority to the overlay accuracy of the joint region using the alignment mark at the time of the alignment, and corrects the position based on the correction amount;
The exposure apparatus according to claim 1, wherein:   The correction amount is at least one of a shift component in a direction orthogonal to the scanning direction, a shift component in the scanning direction, a magnification component in a direction orthogonal to the scanning direction, a magnification component in the scanning direction, or a rotation component. The exposure apparatus according to claim 4. A light shielding member that moves in the scanning direction in synchronization with scanning of the substrate and that can block illumination light that illuminates the first pattern region and the second pattern region;
The controller, when exposing the joint area included in the first image, linearly decreases the exposure amount by moving the light shielding member so as to gradually shield the illumination light. When exposing the connection area included in the image of 2, the exposure amount is linearly increased by moving the light shielding member so as to gradually irradiate the illumination light,
6. An exposure apparatus according to claim 1, wherein An exposure method for connecting a first image and a second image to expose a pattern forming region on a substrate with an image having a larger area than the first image or the second image,
A first pattern region for forming the first image and a second pattern region for forming the second image are connected to each other in the pattern formation region in a connecting region in the scanning direction of the substrate. Forming at least one or more alignment marks;
A step of performing alignment when forming a next layer on the image using the alignment mark;
An exposure method comprising: A step of exposing the substrate using the exposure apparatus according to any one of claims 1 to 6 or the exposure method according to claim 7;
Developing the exposed substrate;
A device manufacturing method comprising:

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