JP4914043B2 - Exposure equipment - Google Patents

Description

  The present invention relates to an exposure apparatus that directly exposes an exposure pattern on an object to be exposed without using a photomask, and more specifically, to improve the overlay accuracy of the exposure pattern with respect to a reference pattern formed on the object to be exposed. This relates to an exposure apparatus.

  A conventional exposure apparatus uses a photomask in which a mask pattern corresponding to an exposure pattern is formed in advance on a transparent glass substrate, and transfers and exposes the mask pattern on an object to be exposed. For example, a stepper or proximity ( Proximity) devices. However, in these conventional exposure apparatuses, when a plurality of patterns are stacked and formed, the overlay accuracy of the exposure patterns between the layers becomes a problem. In particular, in the case of a large photomask used for forming a TFT substrate or a color filter for a large liquid crystal display, high absolute dimensional accuracy is required for the arrangement of the mask pattern, and the cost of the photomask has increased. Further, in order to obtain the above overlay accuracy, alignment between the reference pattern of the underlayer and the mask pattern is necessary, and this alignment is particularly difficult in a large photomask.

On the other hand, there is an exposure apparatus that directly exposes a pattern based on CAD data stored in a storage unit in advance using an electron beam or a laser beam without using a photomask. This type of exposure apparatus includes a laser light source, an exposure optical system that reciprocally scans a laser beam emitted from the laser light source, and a transport unit that transports the object to be exposed, based on CAD data. While controlling the emission state of the laser light source, the laser beam is reciprocally scanned and the object to be exposed is transported in a direction orthogonal to the scanning direction of the laser beam, and a CAD data pattern corresponding to the exposure pattern is formed on the object to be exposed. It is formed two-dimensionally (see, for example, Patent Document 1).
JP 2001-144415 A

  However, in such a direct exposure type conventional exposure apparatus, a high absolute dimensional accuracy is required for the pattern arrangement of CAD data, similar to the exposure apparatus using a photomask. Further, in a manufacturing process in which a pattern is formed using a plurality of exposure apparatuses, there is a problem that the overlay accuracy of the exposure pattern is deteriorated if there is a variation in accuracy between the exposure apparatuses. In order to cope with such a problem, a highly accurate exposure apparatus is required, and the cost of the exposure apparatus has increased.

Furthermore, the point that the alignment of the pattern of the underlayer and the CAD data pattern must be taken in advance is the same as other exposure apparatuses using a photomask, and the alignment accuracy cannot be improved as described above. there is a problem in that.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an exposure apparatus that addresses such a problem and improves the overlay accuracy of an exposure pattern with respect to a reference pattern formed on an object to be exposed.

In order to achieve the above object, an exposure apparatus according to the present invention is provided with a transport means for placing an object to be exposed on a placement surface and transporting it in a predetermined direction, and disposed above the transport means, on a semiconductor substrate. A plurality of micromirrors arranged in a predetermined state, each micromirror is individually tilted based on a drive control signal inputted thereto, and the intensity is modulated on the incident exposure light to be emitted; and the semiconductor substrate wherein the micromirror device at the top is the conveying direction leading end portion is close to the micromirror device of arrangement of the object to be exposed, the plurality of micro-mirrors said direction perpendicular to the conveying direction of the object to be exposed imaging means for imaging the reference pattern on the object to be exposed by a plurality of light receiving elements arranged in correspondence with the respective one-to-one arrangement, the conveying means and the micro-mirror device and shooting And a projection for projecting the light emitted from the micromirror onto the object to be exposed and forming an image of a reference pattern on the object to be exposed on the light receiving element surface of the imaging means. Based on image data obtained by binarizing the image of the reference pattern imaged by the lens and the imaging means, each micromirror of the micromirror device is tilt-controlled to expose the reference pattern. And a control means for enabling.

With such a configuration, the object to be exposed is placed on the placement surface by the transport means and transported in a predetermined direction, and the micromirror is mounted on the semiconductor substrate on which the plurality of micromirrors of the micromirror device are disposed in a predetermined state. Arranged in a one-to-one correspondence with the direction of the plurality of micromirrors in the direction perpendicular to the transport direction of the object to be exposed, in proximity to the micromirror device at the head of the device in the transport direction of the object to be exposed The reference pattern on the object to be exposed is imaged through the projection lens by the plurality of light receiving elements of the image pickup means, and the control means controls the micro pattern based on the image data obtained by binarizing the image. Each micro mirror of the mirror device is tilted, the exposure light from the exposure light source is reflected to modulate the intensity of the exposure light, and the exposure light whose intensity is modulated by the projection lens is applied to the object to be exposed. To shadow.

  In the micromirror device, a plurality of micromirrors are arranged in a straight line in a direction perpendicular to the transport direction within a plane parallel to the mounting surface of the transport means. Thereby, intensity modulation is applied to the exposure light by a micromirror device in which a plurality of micromirrors are arranged in a straight line in a direction perpendicular to the transport direction of the object to be exposed in a plane parallel to the mounting surface of the transport means.

  In the micromirror device, a plurality of micromirrors are arranged in a matrix in a plane parallel to the mounting surface of the transport unit. Thereby, intensity modulation is applied to the exposure light by a micromirror device in which a plurality of micromirrors are arranged in a matrix in a plane parallel to the mounting surface of the conveying means.

  The image pickup unit is configured by arranging the plurality of light receiving elements in a straight line in a direction perpendicular to the transfer direction of the object to be exposed in a plane parallel to the placement surface of the transfer unit. As a result, the reference pattern on the object to be exposed is picked up by the image pickup means in which a plurality of light receiving elements are arranged in a straight line in a direction orthogonal to the transport direction of the object to be exposed in a plane parallel to the mounting surface of the transport means To do.

According to the first aspect of the present invention, the micromirrors of the micromirror device and the light receiving elements of the imaging means are arranged in a one-to-one correspondence with each other in the direction orthogonal to the transport direction of the object to be exposed. Since they are arranged close to each other on the same semiconductor substrate, the reference pattern formed on the object to be exposed can be imaged and exposed to the reference pattern immediately, and the influence of the displacement of the object to be exposed As a result, the overlay accuracy of the exposure pattern with respect to the reference pattern can be improved. Therefore, even when a plurality of patterns are stacked, the accuracy of overlaying the patterns of each layer is increased. In addition, even when a multilayer pattern is formed using a plurality of exposure apparatuses, it is possible to eliminate the problem of deterioration of the overlay accuracy of the pattern of each layer due to the difference in accuracy between the exposure apparatuses. Up can be suppressed.

  Moreover, according to the invention which concerns on Claim 2, the structure of a micromirror device becomes simple and can reduce cost.

  Furthermore, according to the third aspect of the present invention, a complicated exposure pattern can be easily created based on CAD data without using a photomask.

  According to the fourth aspect of the present invention, the micromirror device corresponding to the light receiving states of the plurality of light receiving elements of the imaging means may be driven on / off, and the drive control of the micromirror device is facilitated. In particular, when the micromirror device has a plurality of micromirrors arranged in a straight line, the position of the micromirror device and the object to be exposed even if the object to be exposed moves while swinging in a direction perpendicular to the transport direction. There is no need to match. Therefore, the apparatus is simplified and the cost of the apparatus can be reduced. Further, even if the reference pattern on the object to be exposed has a complicated shape, the exposure pattern can be easily formed according to the shape, and the CAD data is not required, so that the apparatus is further simplified.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing an embodiment of an exposure apparatus according to the present invention. This exposure apparatus directly exposes an exposure pattern on an object to be exposed without using a photomask, and includes a conveying means 1, an exposure light source 2, a micromirror device 3, an imaging means 4, a projection lens 5, and the like. The illumination light source 6 and the control means 7 are included. Hereinafter, a case where the object to be exposed is a color filter substrate will be described.

  The transport means 1 places the color filter substrate 8 coated with a color resist on the placement surface 1a on the stage 9, and transports it at a predetermined speed in the direction of arrow A shown in FIG. For example, a conveyance roller (not shown) that moves the stage 9, a conveyance drive unit such as a motor that rotationally drives the conveyance roller, a position detection sensor such as an encoder or a linear sensor, and a speed sensor are provided. Position detection and speed control are made possible by feeding back to the control means 7 described later.

An exposure light source 2 is provided above the conveying means 1. The exposure light source 2 emits exposure light including ultraviolet rays, and is, for example, a high-pressure mercury lamp, a xenon lamp, an ultraviolet light emitting laser, or the like. Then, so as to irradiate the exposure light micromirror device 3 will be described later from an oblique direction.

  A micromirror device 3 is provided in front of the exposure light source 2 in the exposure light irradiation direction. The micromirror device 3 irradiates a color filter substrate 8 coated with a color resist with exposure light to form an exposure pattern of a color filter of a predetermined color. A plurality of micromirror devices 3 are formed on a silicon substrate 11 as a semiconductor substrate. The micromirrors 10 are arranged in a predetermined state, and each micromirror 10 is individually tilted based on a drive control signal inputted thereto, and the exposure light incident from the exposure light source 2 is applied with on / off intensity modulation and emitted. It is like that. In this embodiment, as shown in FIG. 2, the micromirror device 3 has a plurality of micromirrors 10 transported by an arrow A in the plane parallel to the mounting surface 1a of the transport means 1. They are arranged in a straight line in a direction perpendicular to the direction.

  As shown in FIG. 3A, the micromirror 10 forms a yoke 13 pivotally supported by a pair of hinges 12 on a silicon substrate 11, and reflects exposure light on the upper surface of the yoke 13. A reflection plate 14 is formed. Then, as shown in FIG. 2B, a pair of electrodes 15 is provided opposite to the lower surface of the yoke 13 and the upper surface of the silicon substrate 11, and a voltage is applied to the pair of electrodes 15, thereby providing a gap between the electrodes 15. An electrostatic attraction force or a repulsive force is generated at the center, the yoke 13 tilts in the direction of the arrow about the hinge 12, and the reflector 14 tilts. In this case, in the exposure-on state, as shown in FIG. 4A, the reflection plate 14 of the micromirror 10 is tilted so that the reflected light passes through the projection lens 5, and in the exposure-off state, FIG. As shown, the reflected light is inclined so as not to pass through the projection lens 5. In the following description, the driving state of the micromirror 10 as shown in FIG. 4A is referred to as ON driving, and the driving state of the micromirror 10 as shown in FIG.

As shown in FIG. 2, the micromirror device 3 is imaged close to the micromirror device 3 on the top side in the transport direction (arrow A direction) of the color filter substrate 8 of the micromirror device 3 on the silicon substrate 11. Means 4 are provided. This image pickup means 4 has pixels 17 of a black matrix 16 as a reference pattern on the color filter substrate 8 (see FIG. 5) at a position (image pickup position) P2 on the color filter substrate 8 on the front side in the transport direction of the exposure position P1. For example, a line CCD in which a plurality of light receiving elements 18 that receive light from the color filter substrate 8 are arranged in a straight line in a direction orthogonal to the transport direction (arrow A direction) as shown in FIG. It is. In this case, the plurality of light receiving elements 18 are arranged in a one-to-one correspondence with each other in the direction orthogonal to the conveyance direction (arrow A direction) of the color filter substrate 8 of the plurality of micromirrors 10. The light receiving element 18 is separated from the micromirror 10 by a distance d.

  The light receiving element 18 of the imaging means 4 is formed integrally with the micromirror 10 of the micromirror device 3 on the silicon substrate 11. In this case, the micromirror forming region 19 set on the silicon substrate 11 is masked with, for example, a photoresist, and a light receiving element 18 is formed by applying a known technique to the light receiving element forming region 20. Further, the micromirror 10 is formed by applying a known technique to the micromirror forming region 19 by masking the light receiving element forming region 20 with, for example, a photoresist. At this time, if the light receiving element 18 and the micromirror 10 are formed on the silicon substrate 11 with reference to a preset reference position, the alignment between the corresponding light receiving element 18 and the micromirror 10 can be performed with high accuracy. .

  As shown in FIG. 1, one projection lens 5 is disposed between the transport unit 1, the micromirror device 3, and the imaging unit 4. The projection lens 5 projects an image of the micromirror 10 of the micromirror device 3 onto the surface of the color filter substrate 8, and constitutes a telecentric optical system by combining a plurality of lenses. Further, the image of the pixel 17 of the black matrix 16 formed on the color filter substrate 8 can be taken into the surface of the light receiving element 18 of the imaging means 4 through the projection lens 5.

  An illumination light source 6 is provided below the stage 9 of the conveying means 1. The illumination light source 6 illuminates the imaging position P2 by the imaging means 4 with visible light so that the pixels 17 of the black matrix 16 formed on the color filter substrate 8 made of a transparent glass substrate can be imaged with transmitted light. It is back lighting. Thereby, the contrast of the image of the pixel 17 becomes clear and imaging accuracy is improved. In this case, the stage 9 corresponding to the exposure region of the color filter substrate 8 is provided with an opening (not shown) that penetrates the back surface of the color filter substrate 8 so that illumination light can be irradiated. In addition, the illumination light source 6 is not limited to the one that is arranged below the stage 9 and used as the back illumination, but may be arranged above the stage 9 to provide epi-illumination. When the illumination light contains an ultraviolet component, an ultraviolet cut filter (not shown) is disposed in front of the illumination light source 6 to prevent the color resist applied on the color filter substrate 8 from being exposed. Also good.

  Control means 7 is provided in connection with the exposure light source 2, the micromirror device 3, the imaging means 4, the transport means 1, and the illumination light source 6. The control means 7 detects a reference position S1 (see FIG. 5) set in advance in the pixels 17 of the black matrix 16 on the color filter substrate 8 picked up by the image pickup means 4, and uses the reference position S1 as a reference. Controls the driving of the micromirror device 3, and includes an exposure light source drive unit 21, a mirror drive controller 22, an image processing unit 23, a transport means controller 24, an illumination light source drive unit 25, and a storage unit 26. , A calculation unit 27 and a control unit 28 are provided.

Here, the exposure light source drive unit 21 drives the exposure light source 2 to turn on. The mirror drive controller 22 controls on / off drive of the micromirror 10 of the micromirror device 3 in accordance with the light receiving state of the light receiving element 18. Further, the image processing unit 23 outputs the image data of the image of the pixel 17 of the black matrix 16 imaged by the imaging unit 4 and the look-up table (hereinafter, referred to as the image data and the storage unit 26). And a reference position S1 preset for the pixel 17 is detected. Furthermore, the transport means controller 24 moves the stage 9 of the transport means 1 in a predetermined direction at a constant speed. The illumination light source drive unit 25 drives the illumination light source 6 to turn on. Further, the storage unit 26 stores, for example, an LUT for detecting the reference position S1 on the color filter substrate 8. Furthermore, the calculation unit 27 uses the distance D between the imaging position P2 and the exposure position P1 and the transport speed V of the color filter substrate 8 to drive the micromirror device 3 after imaging by the imaging unit 4. The exposure timing time t until the exposure is calculated. And the control part 28 controls drive of said each part appropriately.

Next, the operation of the exposure apparatus configured as described above will be described.
First, when a startup switch (not shown) provided in the apparatus is turned on, the control unit 7 is activated, the illumination light source drive unit 25 turns on the illumination light source 6, and the imaging unit 4 starts imaging. The transport unit 1 is in a standby state with the color filter substrate 8 coated with a color resist placed on a predetermined position on the stage 9. Next, when the exposure start switch not shown is turned on, the stage 9 of the transport means 1 starts moving at velocity V in the direction of the arrow A is controlled by the transport means controller 24.

  When the color filter substrate 8 moves and the pixel 17 of the black matrix 16 reaches the imaging position P2 as shown in FIG. 5A, an image of the pixel 17 is acquired by the imaging means 4 via the projection lens 5. . The image acquired by the imaging unit 4 is subjected to image processing in the image processing unit 23 and binarized to obtain image data. At the same time, the image processing unit 23 compares this image data with the LUT read from the storage unit 26, and when the two data match, the imaging position of the pixel 17 corresponding to the image data, for example, the pixel 17 of the black matrix 16 Is determined as the reference position S1. Then, the time t1 when the reference position S1 is detected is stored in the storage unit 26.

Furthermore, carried in the color filter substrate 8 velocity V, the exposure and is positioned at the exposure position P1 advances the reference position S1 is a distance D is initiated. In this case, the moving distance D is managed by time. That is, the calculation unit 27 calculates the time t during which the color filter substrate 8 is transported by the distance D based on the transport speed V and the data on the distance D between the imaging position P2 and the exposure position P1. Then, when the time t has elapsed since the imaging means 4 detects the reference position S1 (detection time t1), it is determined that the reference position S1 has been set to the exposure position P1, and exposure is started.

  In the exposure, first, the image data of the pixels 17 of the black matrix 16 acquired by the imaging unit 4 is read from the storage unit 26, the mirror drive controller 22 is driven based on this image data, and the micromirror 10 of the micromirror device 3. The tilting is controlled. For example, as shown in FIG. 5A, when the image data is “001111111111001111111111001111...”, The micromirrors 10-3 to 10-12, 10-15 to 10-24, and 10 of the micromirror device 3 shown in FIG. -27 ... is tilted and driven on. As a result, the exposure light incident from the exposure light source 2 is reflected by the micromirrors 10-3 to 10-12, 10-15 to 10-24 and 10-27 to the projection lens 5 side, and passes through the projection lens 5. Then, the color resist substrate 8 is reached and the color resist on the pixel 17 corresponding to the exposure position P1 is exposed (see the exposure region Q1 shown in FIG. 5B).

  Subsequently, the part of the pixel 17 following the exposure area Q1 is imaged by the imaging means 4. Then, the micromirror of the micromirror device 3 shown in FIG. 5A is obtained based on the image data acquired by the imaging means 4, for example “001111111111001111111111001111...” Shown in FIG. 10-3 to 10-12, 10-15 to 10-24 and 10-27... Are tilted and turned on, and exposure is performed in a region Q2 following the exposure region Q1 on the pixel 17 shown in FIG. Executed. Note that the exposure on the pixel 17 may be terminated, for example, by setting the lower left corner of the pixel 17 as the second reference position S2 and stopping the exposure when the reference position S2 is detected. Alternatively, the time T during which the color filter substrate 8 travels by the distance W may be calculated from the width W in the transport direction of the pixel 17 and the transport speed V, and the exposure may be stopped after the time T has elapsed from the start of exposure.

  Similarly, exposure is performed on a predetermined pixel 17 to form an exposure pattern of a color filter. Here, when exposure is performed by skipping a predetermined number of pixels 17 arranged in the transport direction, the number of times of detection of the reference position S1 is counted, and the count is preset and stored in the storage unit 26. The pixel column number to be exposed is compared, and the pixel column in which both match is exposed.

  In the above embodiment, the case where the object to be exposed is the color filter substrate 8 has been described. However, the present invention is not limited to this, and the object to be exposed may be any semiconductor substrate or the like.

An embodiment of an exposure apparatus according to the present invention is a schematic diagram showing. It is a top view which shows the micromirror device arrange | positioned on the same silicon substrate used in the said exposure apparatus, and an imaging means. It is explanatory drawing which shows the structure of the micromirror of the said micromirror device, (a) is a center longitudinal cross-sectional view, (b) is a center cross-sectional view. It is a side view explaining the tilting of the micromirror of the said micromirror device, (a) shows an ON drive state, (b) is an OFF drive state. It is explanatory drawing which shows the exposure operation | movement by the said exposure apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conveyance means 1a ... Mounting surface 2 ... Exposure light source 3 ... Micromirror device 4 ... Imaging means 5 ... Projection lens 7 ... Control means 8 ... Color filter substrate (exposed body)
10 ... Micromirror 11 ... Silicon substrate (semiconductor substrate)
16 ... Black matrix 17 ... Pixel (reference pattern)
18. Light receiving element

Claims (4)

Conveying means for placing the object to be exposed on the placing surface and conveying the object in a predetermined direction;
A plurality of micromirrors are arranged in a predetermined state on the semiconductor substrate, disposed above the transport means, and each micromirror is individually tilted based on an input drive control signal, and the intensity of incident exposure light A micromirror device that emits light with modulation,
Wherein the micromirror device at the semiconductor substrate in proximity with the micromirror device to the portion of the conveying direction leading side of the object to be exposed is arranged, perpendicular to the transport direction of the object to be exposed of the plurality of micromirrors Imaging means for imaging a reference pattern on the object to be exposed with a plurality of light receiving elements arranged in a one-to-one correspondence with each other in a direction to be
An image of a reference pattern on the object to be exposed is formed on the light receiving element surface of the imaging unit, and emitted light from the micromirror is disposed between the transport unit, the micromirror device, and the imaging unit. A projection lens that projects onto the object to be exposed;
Based on the image data obtained by binarizing the image of the reference pattern imaged by the imaging means, each micromirror of the micromirror device is tilt-controlled to allow exposure on the reference pattern. Control means;
An exposure apparatus comprising:   2. The exposure apparatus according to claim 1, wherein the micromirror device includes a plurality of micromirrors arranged in a straight line in a direction perpendicular to the transport direction within a plane parallel to the mounting surface of the transport unit. .   2. The exposure apparatus according to claim 1, wherein the micromirror device has a plurality of micromirrors arranged in a matrix in a plane parallel to the mounting surface of the transport means.   The image pickup means is characterized in that the plurality of light receiving elements are arranged in a straight line in a direction perpendicular to the transfer direction of the object to be exposed within a plane parallel to the mounting surface of the transfer means. The exposure apparatus according to any one of 1 to 3.

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