TW201736977A - Exposure device and exposure method - Google Patents

Abstract

To provide an exposure technique suitable for small-volume production of multiple products which is neither burdensome nor costly even when performing exposure with different exposure patterns for different types of products. Alignment marks AM on a workpiece W are imaged with cameras 7 through a transmission-type digital photomask 2, and on the basis of the image data, a correction program on a controller 4 corrects the original pattern data. The correction includes correction of the display position of a master pattern and correction of magnification. Light from the light source 1, which includes ultraviolet rays, is irradiated through the corrected mask pattern onto the workpiece W, and the workpiece W is exposed.

Description

Exposure device and exposure method

The invention of the present invention is an exposure technique related to photolithography.

Photolithography is a technique for making a fine shape in an object, and is used in various applications. Typically, photolithography is performed in order to form a circuit pattern for manufacturing a printed circuit board mounted on various electronic devices. In photolithography, there is an exposure process of irradiating light of a shape to be obtained to an object, and an exposure device is used.

The exposure apparatus is various in the form of projection exposure, contact exposure, proximity exposure, and the like. The above-described method is a configuration in which light from a light source is irradiated to an object (hereinafter referred to as a workpiece) via a photomask. The mask is formed of a light-shielding material such as chrome on a transparent glass substrate such as a quartz glass substrate, and the light is transmitted and blocked by the pattern. This pattern is the same as the pattern to be formed on the workpiece, whereby the light of the pattern is projected or transferred onto the workpiece for exposure. Hereinafter, a pattern of light that is irradiated onto the workpiece is referred to as an exposure pattern, and a pattern formed on the mask is referred to as a mask pattern.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 6-232024

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-87771

In the conventional exposure apparatus described above, since the patterns formed in the case of different types of products are different, it is necessary to prepare the respective masks in accordance with various types, and the cost of management cannot be ignored in addition to the cost of the mask itself. This point is a production site with a large number of small-scale production, and the deeper the problem.

The invention of the present invention has been made in consideration of the above-mentioned problems, and has been proposed to provide an exposure technique suitable for various types of small-scale production, even when exposure to different types of exposure patterns is performed in different types, without consuming or costly.

In order to solve the above problems, the invention of claim 1 includes a light source that emits light including ultraviolet light, a transmissive digital mask, and a transport system that transports the workpiece to a light source that passes through the digital mask. a position at which the light is irradiated; a camera that picks up a specific portion of the workpiece that is transported to the irradiation position of the light; and a controller that, in addition, a digital mask, has a plurality of pixels controlled by the controller, each of the paintings The system has a memory unit that stores a pattern of data for displaying the mask pattern on the digital mask; The output unit outputs the pattern data to the digital mask, and displays the mask pattern on the digital mask, and a correction program is installed in the controller to correct the pattern data according to the camera data of the camera. The pattern data can be output from the output unit, and the correction program includes a display position correction module for correcting the display position of the mask pattern on the digital mask according to the image data of the specific portion of the workpiece of the camera.

In addition, in the configuration of the above-mentioned claim 1, the invention of the above-mentioned claim 1 has a configuration in which a specific portion of the workpiece is an alignment mark.

In order to solve the problem, the invention of claim 3 is characterized in that the number of the alignment marks is plural, and the camera is configured to take in each of the alignment marks.

In order to solve the problem, the invention of claim 3 is the configuration of the request item 3, wherein the camera system is provided in a position where each of the alignment marks can be ingested.

Further, in order to solve the above-described problems, the invention of claim 5, wherein the modification program includes determining the mask of the digital mask in accordance with the image data of the alignment mark of the camera. The composition of the expansion and contraction module of the display magnification of the cover pattern.

In addition, in the configuration of the above-mentioned claim 3, 4 or 5, the invention according to the invention of claim 3, wherein the correction program includes determining the deformation of the workpiece in accordance with the image data of the alignment mark of the camera. The mask pattern is formed by deforming the deformation module according to the judgment result.

In addition, in the configuration of any one of the above-mentioned claims 1 to 6, the digital photomask has a light transmitting portion that transmits light of an imaging wavelength of the camera, and The camera is disposed so as to be able to pass through the transparent portion of the digital mask to focus on the position of the specific portion.

In order to solve the problem, the invention of claim 8 is characterized in that the configuration of the above-mentioned claim 7 includes a moving mechanism that moves the workpiece or the photomask that is transported to the irradiation position. The state in which the workpiece is in contact with the digital reticle or the state in which the predetermined gap is opposed is set.

Moreover, in order to solve the above problem, the invention according to claim 9 is the configuration of the above-mentioned claim 1, wherein the specific portion of the workpiece is provided by The configuration of the specific portion of the pattern formed by photolithography.

In addition, in the invention of claim 10, the exposure method of the exposure apparatus according to any one of the above claims 1 to 9 is used.

The exposure apparatus includes a stage that is disposed at an irradiation position of the light, and a moving mechanism that moves the stage or the digital mask in a state in which the workpiece is placed on the stage to bring the digital mask into contact with the workpiece. The photographing step is characterized in that after the digital mask is in contact with the workpiece, the camera is used to perform photographing of a specific portion of the workpiece through the digital mask; and the correcting step is performed according to the image data obtained in the photographing step. Executing the correction program; and an exposure step of exposing the workpiece while the mask pattern is displayed on the digital mask by the pattern data corrected by the correction program, from the photographing step to the end of the exposure step The state in which the positional relationship between the two positions of the photomask is in contact with the workpiece does not change.

In the exposure method of the exposure apparatus according to any one of claims 1 to 9, the exposure apparatus includes a platform disposed at an irradiation position of the light, and an exposure method according to the invention. And making the platform or the aforementioned digital light in a state where the workpiece is placed on the platform a moving mechanism for moving the cover to contact the digital mask with the workpiece, and a vacuum for exhausting the space between the digital mask and the workpiece in a state where the digital mask is in contact with the workpiece, and the two are closely adhered The system has a photographing step of photographing a space between the photomask and the workpiece by vacuum evacuation, and then passing through the digital mask to perform photographing of a specific portion of the workpiece by using the camera. a correction step of performing the correction program according to the image data obtained in the photographing step; and an exposure step of displaying the mask pattern on the digital mask by the pattern data corrected by the correction program While the workpiece is exposed, the space between the digital reticle and the workpiece is evacuated by vacuum evacuation while the exposure step is completed, and the state in which the two are in close contact continues.

As described below, according to the invention of claim 1 of the present invention, since the exposure is performed using the digital mask, it is not necessary to replace the hard mask even when performing exposure for different types of products. It is not necessary to prepare a hard mask for each type to manage. Therefore, it is possible to provide an exposure apparatus which is high in productivity and inexpensive in operation. Further, the mask pattern is displayed by the pattern data corrected by the display correction data calculated based on the imaging result of the specific portion of the workpiece, and the workpiece is exposed by the light passing through the mask pattern, so that alignment is not required. . Place Therefore, this point makes the cost of the device cheaper and the productivity becomes higher.

According to the invention described in the second aspect of the invention, in addition to the above-described effects, the photographer takes the alignment mark provided on the workpiece and calculates the display correction data, so that the data processing is easy.

Further, according to the invention of claim 3, in addition to the above-described effects, since a plurality of alignment marks are provided, there is no need for a camera having a very high resolution, or the accuracy of the expansion of the mark is determined by the expansion and contraction of the mark. The problem.

Further, according to the invention described in the claim 4, in addition to the above-described effects, since the camera is provided for each of the alignment marks, the movement mechanism of the camera is not required, and the accuracy of the stop position does not matter. Therefore, superior results can be obtained in terms of cost and exposure quality.

Further, according to the invention described in the claim 5, in addition to the above-described effects, even if the size of the workpiece changes, the mask pattern can be corrected in accordance with the dimensional change, and the exposure is performed in the corrected state, so that the dimensional change and the final When the relationship of the product is allowable, pattern formation corresponding to an allowable dimensional change is performed. Therefore, the yield of the product can be improved.

According to the invention of claim 6, in addition to the above-described effects, even if the workpiece is deformed, the mask pattern can be corrected in accordance with the deformation, and the exposure is performed in the corrected state. Therefore, the relationship between the deformation and the final product is When it is permissible, the pattern is formed in a state corresponding to the deformation of the allowable workpiece. Therefore, the yield of the product can be improved.

Further, according to the invention described in claim 7, in addition to the above effects, the alignment mark is taken through the digital mask, and therefore the alignment mark is taken. The parallax will be smaller. Therefore, more accurate data correction can be performed.

Further, according to the invention described in the claim 9, in addition to the above-described effects, when the pattern of the hierarchical structure is formed, the pattern of each layer is formed in a state where the positional deviation or the deformation is corrected, so that a more favorable multilayer structure can be obtained. picture of.

According to the invention of claim 10, in addition to the above-described effects, the state in which the positional relationship between the two reticle and the workpiece are not changed is maintained, and the pattern data to which the correction data is applied is displayed on the digital mask. , for exposure. Therefore, there is no case where the positional deviation of the workpiece occurs after the camera is photographed, and the display correction data is not correct. The technical configuration of the correction of the mask pattern in accordance with the imaging result of the camera becomes more meaningful.

Further, according to the invention described in the claim 11, in addition to the above-described effects, the state in which the position of the photoreceptor and the workpiece by vacuum evacuation are kept intact, and the pattern data to which the correction data is applied is displayed on the digital mask. exposure. Therefore, the above effects can be obtained more reliably.

1‧‧‧Light source

2‧‧‧Digital mask

3‧‧‧Transfer Department

31‧‧‧ moving into the side conveyor

32‧‧‧Removing side conveyor

33‧‧‧Hand in hand

34‧‧‧ Moved out

4‧‧‧ Controller

41‧‧‧ Processor

42‧‧‧Memory Department

43‧‧‧Import and Export Department

5‧‧‧Optical Optics

6‧‧‧ platform

61‧‧‧Vacuum adsorption holes

62‧‧‧Mobile agencies

63‧‧‧Weighed sealing members

64‧‧‧ venting holes

7‧‧‧ camera

8‧‧‧Exhaust system

Fig. 1 is a schematic view of an exposure apparatus according to an embodiment.

Fig. 2 is a flow chart showing the main part of a sequence program of the apparatus of the embodiment.

3 is a flow chart showing an outline of a correction program.

Fig. 4 is a conceptual diagram for the specificity of the origin of the image.

FIG. 5 is a conceptual diagram showing a display position correction module.

Fig. 6 is a conceptual diagram showing the expansion and contraction module.

Fig. 7 is a conceptual diagram showing a deformation module.

8 is a front cross-sectional schematic view showing the overall operation of the exposure apparatus according to the embodiment.

Next, a mode for carrying out the invention of the present invention (hereinafter referred to as an embodiment) will be described.

Fig. 1 is a schematic view of an exposure apparatus according to an embodiment. The exposure apparatus shown in FIG. 1 is configured to include a light source 1, a mask 2, a transport system 3, and a controller 4 of each unit of the control device.

The light source 1 is a person who emits at least ultraviolet light. For example, a short arc type or a long arc type mercury lamp or the like is used as the light source 1.

The photomask 2 is an exposure apparatus of this embodiment as a large feature point, and a transmissive digital mask 2 is used. Although the digital mask 2 is not a general term, it is a photomask that displays a mask pattern in digital form.

The digital mask 2 has a plurality of pixels controlled by the controller 4, and each pixel acquires an ON-OFF pattern of the pixels in an OFF state in which ultraviolet rays are transmitted and an ON state in which ultraviolet rays are blocked. For the mask pattern that is displayed.

As such a digital mask 2, in this embodiment, a transmissive liquid crystal display is used. For example, a high resolution TFT color liquid crystal display having a pixel pitch of about 10 to 100 μm can be used. But because the backlight is It is not required, so it is used in the state of being removed. Further, a commercially available liquid crystal display has a case where an ultraviolet cut filter is provided, but this case is also removed.

The structure of the optical system differs depending on the manner of exposure. The device of this embodiment is a device for performing contact exposure, and an illuminating optical system 5 is disposed between the light source 1 and the digital mask 2. The illumination optical system 5 can be arbitrarily selected from various types. For example, when a short-arc type ultraviolet lamp is used as the light source 1, an integrator lens can be used to set the light from the light source 1 to a uniform intensity distribution. After the light beam, the collimator lens is used as the parallel light to illuminate the configuration of the digital mask 2. The light intercepted by the digital mask 2 is controlled to maintain the parallel light reaching the workpiece W and expose the workpiece W. The illumination optical system 5 includes a shutter (not shown), and the shutter is controlled by the controller 4.

Further, when projection exposure is performed, a projection optical system is disposed between the digital mask 2 and the workpiece W. The projection optical system projects a mask pattern on the digital reticle 2 to illuminate the workpiece W.

A platform 6 is disposed at a position opposed to the digital mask 2. The stage 6 is a member that holds the workpiece W at a position where the light of the exposure pattern is irradiated. The workpiece W is held on top of the platform 6. The stage 6 has a vacuum suction hole 61 on the upper surface for preventing the workpiece W from moving on the stage 6, and an exhaust system 8 for evacuating the vacuum adsorption hole 61 and vacuum-absorbing the workpiece W. The stage 6 is provided with a workpiece sensor (not shown), and the workpiece W can be confirmed by the workpiece sensor. The workpiece sensor is connected to the controller 4.

The transport system 3 is optimized according to the type of the workpiece W. In this embodiment, it is an exposure apparatus for a rigid type of printed circuit board. Therefore, in this embodiment, the transport system 3 is constituted by the conveyors 31, 32 and the transport hands 33, 34 and the like.

The conveyors 31 and 32 are provided on the loading side and the unloading side (hereinafter referred to as a conveyor side conveyor and a carry-out conveyor), and the transporting hands 33 and 34 are also provided on the carry-in side and the carry-out side (hereinafter referred to as a carry-in hand). , move out). In this embodiment, the conveying direction is the horizontal direction. Hereinafter, for the convenience of explanation, the transport direction (the horizontal direction on the paper surface of FIG. 1) is referred to as the X direction, and the horizontal direction (the direction perpendicular to the paper surface of FIG. 1) perpendicular to the X direction is referred to as the Y direction.

The carry-in hand 33 is a mechanism for picking up the workpiece W conveyed by the carry-in conveyor 31 and placing it on the stage 6. The carry-out hand 34 is a mechanism for picking up the exposed workpiece W from the stage 6 and placing it on the carry-out side conveyor 32. . Each of the hands 33, 34 is provided with an adsorption pad (not shown) that adsorbs the workpiece W at the lower end, and includes hand drive mechanisms 331, 341. Each of the hand drive mechanisms 331, 341 is a mechanism that moves each hand in the horizontal direction and the vertical direction. The transfer of the workpiece W is performed by these mechanisms.

Further, the device is a moving mechanism 62 having a moving platform 6. The moving mechanism 62 is a mechanism for adjusting the distance of the platform 6 placed on the photomask 2 to be optimal. In this embodiment, the contact exposure is performed to cause the workpiece W to be placed in contact with the movement of the digital mask 2. Therefore, the moving mechanism 62 is an elevating mechanism in this embodiment. In addition, regarding the digital optical mask 2 The distance relative to the workpiece W (including the distance zero) is adjusted in response to the need to have a moving mechanism.

Further, the device of the embodiment is configured to evacuate the workpiece W and the digital mask 2 in order to improve the adhesion of the digital mask 2 to the workpiece W. Specifically, as shown in FIG. 1, a circumferential sealing member 63 such as an O-ring is provided on the surface of the stage 6. The digital photomask 2 has the frame portion 21, and when the stage 6 is raised by the moving mechanism 62 as will be described later, the frame portion 21 abuts against the circumferential sealing member 63 and is in close contact with each other. The workpiece W is placed on the inner side of the circumferential seal member 63. The stage 6 is formed with a vent hole 64 for abutment between the workpiece W placed on the surface and the circumferential sealing member 63. The vacuum between the workpiece W and the digital mask 2 is evacuated from the exhaust hole 64, and the adhesion of the digital mask 2 to the workpiece W is improved.

Further, a camera 7 that picks up an alignment mark of the workpiece W conveyed to the irradiation position is provided. The alignment mark is provided at least two on the surface of the workpiece W. In cooperation with this, at least two cameras 7 are provided in this embodiment. For example, if the alignment mark is four, the camera 7 is also provided with four.

The arrangement position of each camera 7 is a position (in the range of the visual field) at which the alignment mark of the placed workpiece W can be taken when the workpiece W is placed on the set placement position. Each of the cameras 7 is a camera 7 which employs a CCD camera 7 and adopts a high resolution corresponding to the pixel pitch of the digital mask 2. For example, a pixel pitch of about 2 μm to 10 μm is used. Further, each camera 7 picks up each alignment mark through the digital mask 2. Each camera is a person who sets the visible light as the imaging wavelength, but the digital mask 2 is There is a transmission through the visible light. The transmission portion is configured by setting a point group of a certain area to a transmission state, similarly to the display of the mask pattern.

Further, each camera 7 is connected to the controller 4, and data (hereinafter referred to as image data) acquired by the imaging of each camera 7 is transmitted to the controller 4. The memory unit of the controller 4 is for each camera 7 to secure the memory area, and the image data from each camera 7 is stored in each memory area, and is updated by the frame period of each camera 7.

The controller 4 is a control means including a processor that executes various programs, and uses a programmable control device such as a PLC (Programmable Logic Controller) as the controller 4. As shown in FIG. 1, the controller 4 is provided with a processor 41, a memory unit 42 such as a memory, an input/output unit (1/O) 43, and the like. Further, various programs are stored in the storage unit 42, and a sequence program is included.

As described above, the digital mask 2 is used to control the transmission of light by the mask pattern formed. The light projection of the exposure pattern is transferred onto the workpiece W by occlusion. In the apparatus of this embodiment, the digital mask 2 is connected to the controller 4, and display by the data transmitted from the controller 4 becomes a mask pattern. Hereinafter, the material for display of this mask pattern is referred to as pattern data. Further, the input/output unit 43 of the controller 4 functions as an output unit of the embodiment, and outputs a portion of the pattern data to the photomask 2.

The controller 4 controls the transport system 3 to carry the workpiece W one by one and mounts it on the stage 6, and outputs the pattern data to the digital mask 2 to display the mask pattern, and exposes the workpiece W in this state. Scheduled time After the exposure, the workpiece W is picked up from the stage 6 and carried out. The sequence program will be installed on the controller 4, and will be enabled in such a sequential operation. In such a sequence program, the display of the mask pattern using the digital mask 2 and the exposure of the workpiece W using the same are optimized. Below, explain this point.

Fig. 2 is a flow chart showing the main part of a sequence program of the apparatus of the embodiment.

In the embodiment, the pattern data is basically prepared in advance and stored in the memory unit 42 of the controller 4. The creation of the pattern data is based on the design information of the final product based on how the pattern is formed on the workpiece W. In addition, the pattern data is data for displaying the image of the digital mask 2, and can also be referred to as certain image data.

Pattern data is stored in the memory unit 42 for each type. Hereinafter, the pattern data of each type of the original stored in the memory unit 42 is referred to as prototype material. The sequence program reads the pattern data of the specified type from the storage unit 42, and transmits it to the digital mask 2 via the input/output unit 43 to display the mask pattern. At this time, the prototype data is corrected in accordance with the image data transmitted from each camera 7, and the corrected pattern data (hereinafter referred to as the corrected pattern data) is transmitted to the digital mask 2. The correction program for this correction will be installed as a subroutine of the sequence program.

More specifically, as shown in FIG. 2, during exposure, the sequential program is to place the workpiece W on the stage 6, and drive the platform 6 to make the workpiece W into contact with the digital mask 2, and by arranging The gas system 8 evacuates the vacuum between the two to make it close. In this state, the sequence program Execute the correction program.

The recovery value of the correction program is how to correct the prototype data and display the data (hereinafter referred to as display correction data). As shown in FIG. 2, the sequence program applies display correction data to the prototype data to obtain the corrected pattern data, and transmits the corrected pattern data to the digital mask 2 to display the mask pattern. In this state, the shutter in the illumination optical system 5 is turned on to perform exposure. Then, after the exposure for a predetermined period of time, the shutter is closed, and the transport system 3 is controlled after the release is released, and the exposed workpiece W is picked up from the platform 6 and carried out. The sequence program will be installed on the controller 4, and will be enabled in such a sequential operation.

Next, the correction program will be described with reference to FIG. 3. 3 is a flow chart showing an outline of a correction program.

As shown in FIG. 2, when the workpiece sensor is confirmed to have the workpiece W placed thereon, the sequence program is called by the correction program and executed. As shown in FIG. 3, once the correction program is started, the image data of each camera 7 is acquired. That is, each of the image data is read from the memory area of the memory unit 42 and temporarily stored as a variable.

Next, the correction program processes the respective image data to calculate the display correction data. The display correction data is a case where the data of the display position of the mask pattern is corrected, a case where the material of the shape of the mask pattern is corrected, or both of them. In any case, the correction program acquires a part of an image (hereinafter referred to as a mark image) that displays an alignment mark from each image data, and specifies a point (hereinafter referred to as an image origin) which serves as a reference for the mark image. This point will be explained with reference to FIG. 4. Figure 4 is a view showing alignment of an embodiment Mark and a specific conceptual map like the origin.

As shown in FIG. 4, the workpiece W is a region (hereinafter referred to as a pattern formation region) WR having a pattern formed by photolithography. The alignment mark AM is a blank area formed on the outer side of the pattern formation region WR. As shown in Fig. 4, in this embodiment, it is provided in a portion of each corner of the contour of the square workpiece W. In this example, the alignment mark AM is a pattern that becomes a circle.

In Fig. 4, a photographing possible area (field of view) 72 of each camera 7 is displayed, exemplifying an image I photographed by a certain camera 7. The data (camera data) of this image I is processed to specify the origin Mo. Although there are several practices regarding the specificity of the origin, in this embodiment, the center of gravity is specified as the origin. The center of gravity of this case is to assume the center of gravity of the case where the plane has a uniform plate having the shape of the mark image. In this example, since the alignment mark AM is circular, the center of the circle becomes the origin Mo, but the coordinates of the plane of gravity of the center of gravity can be calculated as the origin Mo when other shapes such as a star shape or a cross shape are used. .

As shown in FIG. 3, the correction program calculates the offset of the reference point and the image origin Mo after calculating the origin Mo, and calculates the correction data as the amount of the offset (corrected). First, explain the relevant benchmarks.

The reference point at the time of calculation of the display correction data is a reference point at which the workpiece W is placed on the stage 6, and is preferably a reference point on which the platform 6 is placed at this position. Hereinafter, the reference point is referred to as a placement reference point. The placement reference point is indicated by Po in FIG. For example, the workpiece W is square, An alignment workpiece W is formed at each corner of the square, and four cameras are provided in such a manner that the camera 7 can simultaneously take in each alignment mark. In this case, the placement reference point Po is, for example, a point at which the optical axis 51 of the illumination optical system 5 intersects with respect to the stage 6 as a platform origin (indicated by 60 in FIG. 1), with respect to the platform origin 60, The position of each corner of the square extending in the XY direction becomes the placement reference point Po. The size of this square is a square size equivalent to the design information of the four alignment marks. That is, the size of the square of the information set in advance as the formation position of the alignment mark on the workpiece W is the same.

Each of the cameras 7 is disposed at a position facing the placement reference point Po on the platform 6. Usually, it is assumed that the optical axis of the camera 7 (the central axis of the imaging lens of the camera 7) 71 coincides with the placement reference point Po. The carrying handle of the transport system 3 is such that the workpiece W is placed on the stage 6 so that the respective alignment marks of the workpiece W can match the respective placement reference points Po. However, the position of the workpiece W placed on the stage 6 is not the same as the placement reference point because the accuracy of loading 43 hands or the position at the time point on the loading conveyor 41 has been shifted. Po's location. Even so, each alignment mark enters the imaging area of each camera 7. In other words, the positional deviation due to the accuracy of each mechanism is about 0.5 to 1.0 mm at most. On the other hand, each of the cameras 7 has an area of about 7.5 × 10 mm as an imaging area in the imaging distance in the mounted state, and each of the alignment marks is taken with a sufficient margin.

Such a placement reference point Po is also set as a constant in the processing of the image data. For example, when the point on the optical axis 71 of the camera 7 is When the reference point Po is placed, as shown in FIG. 4, the center point of the image I represented by the image data is the placement reference point Po. As shown in FIG. 4, the correction program calculates the image origin Mo from the image data of each camera 7, and determines whether or not the shape (hereinafter referred to as the origin formation pattern) formed by connecting the image origin Mo is square. . In the case of a square shape, it is determined whether or not the square (hereinafter referred to as a reference square) BR formed by connecting the placement reference point Po is substantially the same size. The term "substantially the same size" means that the difference in size of each side is within a certain critical value. When it is approximately the same size, as shown in FIG. 3, the correction program is a display position correction module. The display position correction module is a program that is installed as a subroutine of the correction program. Fig. 5 is a conceptual diagram showing a display position correction module.

The display position correction module calculates the offset amount based on any one of the four placement reference points Po. For example, as shown in FIG. 5, a square (hereinafter referred to as an image square) MR formed by connecting the image origin points Mo with reference to the lower left placement reference point Po is calculated based on the lower left placement reference point Po. Degree offset. In other words, the amount of shift in the X direction from the anchor point Mo of the lower left image of the square MR, the amount of shift in the Y direction, and the amount of shift in the direction of rotation (θ direction) are calculated. The data of the offset amounts are correction data in the XYθ direction (hereinafter referred to as XYθ correction data). The display position correction data includes information on the respective amounts of XYθ and which of the four placement reference points Po is used as a reference. The display position correction module returns the correction program with the display position correction data thus calculated as the recovery value. In addition, there is also a case where θ is zero.

Also, like the origin, the graphic is square, but not with the base. When the quasi-square BR is approximately the same size, the display position correction program is to execute the expansion and contraction module. Fig. 6 is a conceptual diagram showing the expansion and contraction module.

As shown in Fig. 6 (1), in the expansion/contraction module, the offset in the XY direction and the deviation in the θ direction of the square MR are calculated based on any of the four placement reference points Po. shift. That is, the XYθ correction data is calculated. Then, as shown in Fig. 6 (2), the image origin Mo of the corresponding image square MR is made to coincide with the placement reference point Po, and only the inclination angle θ is reversely rotated so that the sides in the XY direction are aligned. concept. In this state, the magnification of how much the square MR is from the reference square BR is calculated, and the magnification is used as the expansion ratio, and is included in the display correction data. In this case, the expansion ratio in the X direction is different from the expansion ratio in the Y direction. In this way, in addition to the XYθ correction data, the expansion/expansion module acquires correction data including the expansion ratio of XY, and returns it to the correction program as a recovery value.

When the pattern formed like the origin is not a square, as shown in FIG. 4, the correction program is a deformation module. Fig. 7 is a conceptual diagram showing a deformation module.

When the pattern formed like the origin is not a square, it means that the workpiece W is deformed like a skew. In this case, there are corrections to possible deformations and corrections that are impossible. The deformation module analyzes the image from the origin to determine whether it can be corrected. For example, as shown in Fig. 7 (1), when the shape formed by connecting the origin Mo is a trapezoid which is symmetrical with respect to the center line Lc, it is possible to correct it. That is, the deformation module is a line portion Lo in which a certain two image origin Mo is connected as a reference line portion, and a line Lc perpendicular to the line portion is a concept through a midpoint of the reference line portion Lo. If the image is formed like the origin relative to the line portion For a symmetrical trapezoid, it is possible to correct.

In this case, as shown in Fig. 7 (1), the deformation program calculates XYθ correction data for matching the reference line portion Lo to the side of the corresponding reference square BR. Then, as shown in Fig. 7 (2), the image originating pattern is reversely moved with respect to XYθ so that the state in which the reference line portion Lo in which the origin is formed into a pattern coincides with the corresponding side of the reference square BR is a concept. At this time, when the length of the reference line portion Lo does not coincide with the length of the corresponding side of the reference square BR, the entire image is enlarged and reduced like the origin, and the expansion ratio at that time is memorized.

Then, in the state shown in Fig. 7 (2), the ratio of the upper side to the lower side of the trapezoid is calculated, and correction data (gradual expansion ratio) which gradually expands or contracts in the direction of the center line Lc is generated. Then, the XYθ correction data, the reciprocal of the overall expansion ratio, and the gradual expansion ratio in the X direction or the Y direction are included in the correction data. The display correction data thus calculated is returned to the correction program as the execution result of the deformation module. The above example is trapezoidal, but the case of a pattern such as a parallelogram or a diamond can be corrected, and the deformation data can be corrected to return to the correction program. In addition, when it is judged that it cannot be deformed, the value of the intention is returned to the correction program as the recovery value.

In this way, each module will be executed according to the conditions, and the display correction data will be obtained in the correction program. The correction program returns the sequence program by the display correction data thus obtained as the execution result of the program, and ends the program. In addition, when the undeformable value is returned by the morphing module, since the uncorrectable skew occurs in the workpiece W, the correction program outputs the execution result of the program which cannot be corrected to the sequence program, and the final program is completed. formula.

As shown in FIG. 2, once the correction program is returned to the display correction data, the sequence program is adapted to display the correction data to update the prototype data. That is, the prototype data is updated by correcting the display position of the mask pattern in the XY direction based on the correction data in the XY direction, and the pattern data is corrected. Further, if the θ correction data is included in the display correction data, the rotation center point and the rotation angle are applied to correct the prototype data. Further, if the expansion correction data or the deformation data is included, the data is applied, and the prototype data is corrected by expanding or contracting in the X direction and the Y direction. In this way, the sequence program obtains the corrected pattern data.

Secondly, the sequence program transmits the corrected pattern data to the digital mask 2 to display the mask pattern. In this state, the shutter is opened, and the workpiece W is exposed through the digital mask 2. Further, as shown in FIG. 2, when the recovery value from the correction program is not the display correction data (when it cannot be corrected), the sequence program displays an error message for the display (not shown) provided in the controller 4, Stop the program. Sequential programs and correction programs are designed to behave in such a sequential order.

In addition, the imaging of each of the alignment marks of each of the cameras 7 is vacuum-exhausted by the exhaust system 8, and the digital mask 2 is in close contact with the workpiece W, and the display of the mask pattern to which the correction information is applied is completed, corresponding to the mask. The exposure of the workpiece W of the exposure pattern of the cover pattern is thus maintained in abutment state. Therefore, there is no case where the workpiece W is displaced from the position of the digital mask 2 while the exposure of each of the cameras 7 after the alignment marks are taken.

Next, the relevant embodiment will be schematically explained with reference to FIG. The overall operation of the exposure apparatus. 8 is a front cross-sectional schematic view showing the overall operation of the exposure apparatus according to the embodiment. The following description is an explanation of an embodiment of the invention of the exposure method.

First, as shown in Fig. 8 (1), one piece of the workpiece W is carried in by the carry-in conveyor 31. Then, as shown in Fig. 8 (2), the platform 6 is placed by loading the hand 33. Then, the workpiece W is adsorbed to the stage 6 by vacuum evacuation from the vacuum adsorption hole 62. Next, the moving mechanism 62 operates to raise the stage 6, and the workpiece W is brought into contact with the digital mask 2 as shown in Fig. 8 (3).

Then, vacuum evacuation is performed from the exhaust hole 64 of the stage 6, and the space between the digital mask 2 and the workpiece W is evacuated by vacuum to make the two adhere to each other. In this state, each camera 7 picks up the alignment marks of the workpiece W through the digital mask 2. Each camera transmits the image data to the controller 4, and the controller 4 executes the correction program. As a result, the corrected pattern data is transmitted to the digital mask 2, and the corrected mask pattern is displayed in the digital mask 2.

In this state, the shutter in the illumination optical system 5 is turned on, and the light E from the illumination optical system R is irradiated to the digital mask 2 displaying the corrected mask pattern, and the exposure of the exposure pattern is performed on the workpiece W. After the exposure of the predetermined time, the shutter is closed, and the vacuum exhaust between the digital mask 2 and the workpiece W is released. Then, the moving mechanism 62 lowers the platform 6, as shown in Fig. 8 (4), and returns to the original height. Thereby, the workpiece W is separated from the digital mask 2. Then, the vacuum suction of the workpiece W on the stage 6 is released, as shown in Fig. 8 (5), the hand 34 will be removed. The workpiece W is picked up from the platform 6 and transferred to the carry-out side conveyor 32. Then, the carry-out side conveyor 32 carries out the workpiece W. On the other hand, the carry-in conveyor 31 carries in the next workpiece W, and the same step is repeated for the next workpiece W.

According to the exposure apparatus of the embodiment of the above configuration and operation, the exposure is performed using a digital mask instead of the conventional photomask. Therefore, when performing exposure for different types of products, only the pattern data can be changed, and replacement of the hard mask is not required. Therefore, it becomes a highly productive process. Further, it is not necessary to prepare a hard mask for each type, and it is not necessary to manage a hard mask for each type. Therefore, the running cost is also cheap.

Further, in the exposure apparatus of the embodiment, when the workpiece W is carried in and placed on the stage 6, the image pickup data is processed by ingesting the alignment marks of the workpiece W, and the display correction data of the mask pattern is created. The mask pattern is displayed in a state corrected by displaying the correction data. Then, the light is transmitted and blocked according to the mask pattern that is corrected to be displayed, and the light of the exposure pattern is irradiated onto the workpiece W to be exposed. That is, the workpiece W is exposed while maintaining the state placed on the stage 6, and essentially does not require alignment. Therefore, the device of the embodiment does not require an alignment mechanism and does not require an alignment action. Therefore, at this point, the cost of the device becomes cheaper, and the intermittent time becomes shorter.

Further, even when the workpiece W has a dimensional change or deformation, the mask pattern can be corrected in accordance with the dimensional change or deformation thereof, and exposure is performed in the corrected state. Therefore, when the dimensions change or deform When the relationship of the final article is tolerable, a pattern corresponding to the allowable dimensional change or deformation is formed. Therefore, the yield of the product can be improved. In other words, when the workpiece W has an allowable dimensional change or deformation, if the pattern is formed in a state in which the workpiece W is not provided, the size and shape of the pattern and the workpiece W are unbalanced, so that it is easy to form a product defect. According to the apparatus of the embodiment, the defective product of the cause can be reduced, which can help the yield increase.

Further, the degree to which the dimensional change or the deformation is allowed is the condition to be reflected in the judgment of the above-described correction program. That is, for example, the critical value when it is judged to be a square is to reflect the extent to which the deformation is allowed. The same is true for dimensional changes.

When it is not necessary for the correspondence of the dimensional change or the deformation, the correction program only performs the correction of XYθ. This situation also has the effect of not needing alignment. Further, when the workpiece W is loaded and placed without the θ direction shift, the correction program is programmed to not correct the θ direction. Further, in the correction of the expansion and contraction, the correction of the expansion and the equal magnification is performed in the XY direction, but the correction of the unequal magnification (non-similar correction) may not be performed. If only a similar shape change occurs in the workpiece W, and a non-similar change does not occur, there is a case where this is also done. Further, if the square workpiece W does not change in a non-square shape, there is a case where the correction (deformation) of the non-square is not performed.

In the above embodiment, when the exposure for different types is performed, the mask pattern is of course different. The memory unit 42 of the controller 4 memorizes pattern data of various types. The operator is in a certain class At the start of the batch processing, the controller 4 is operated to perform input of selecting a mask pattern. The controller 4 reads out the selected mask pattern from the storage unit 42, and performs exposure processing of each workpiece W while executing the correction program as described above. The correction program is such that the position at which the reference point Po is placed, the reference square BR, and even the respective threshold values are different for each type. Therefore, the design program is optimized according to the pattern data, and is installed in the controller 4. Therefore, when the exposure processing is performed using different pattern data, the correction program is selected in response to this and executed in the processor 41.

Further, there may be a case where the ID of the product type is printed on the workpiece W. In some cases, the ID may be read by the camera 7 to determine the type, and the controller 4 automatically selects the pattern data.

In the above embodiment, the number of alignment marks is set to four, but the alignment marks are sufficient as long as at least two. If there are two, the display position of XYθ is corrected as possible. Further, when the alignment marks are three, the placement reference point Po also becomes three, and thus the reference pattern is a triangle. Therefore, whether or not the expansion correction is possible is determined by whether or not the pattern formed by the origin forms a triangle substantially similar to the triangle formed by connecting the placement reference point Po.

Further, the number of cameras corresponds to the number of alignment marks, but may not necessarily be the same number. In other words, for example, when two cameras having two alignment marks are provided, a moving mechanism may be provided in the camera, and the camera may be sequentially moved to the imaging position of each of the alignment marks. However, since the display position correction is performed at which position with the alignment mark at the time of imaging, the camera must be accurately stopped at the position to be the reference. According to the above-described embodiment, since the camera is provided for each of the alignment marks, the movement mechanism is not required, and the accuracy of the stop position is irrelevant, so that it is advantageous in terms of cost and exposure quality.

Also, even if the alignment mark is one, it can be implemented. For example, the square pattern that is coated forms an alignment mark, and the XYθ correction data is calculated from the position and inclination angle at which the alignment mark is taken, and the expansion data is calculated by the deviation from the reference size of the image size. . However, if the correction data is to be calculated with only one mark, there is a disadvantage that a camera having a very high resolution is required. Further, if the expansion and contraction of the workpiece W is judged by the expansion and contraction of the mark, there may be a case where the accuracy is not good. Based on the point where there is no such disadvantage, it is preferable to judge by a plurality of alignment marks.

Further, in the above-described embodiment, the camera 7 is disposed at a position where the alignment mark is received by the digital mask 2, but this is not necessarily required. For example, there is a case where each alignment mark is provided on the back surface of the workpiece W. In this case, it is conceivable that the opening for imaging is provided on the stage 6, and the image is imaged from the back side via the opening. The position of the opening is set to a position at which each alignment mark can be eye-catched when the workpiece W is placed. Further, in the case of an optical system for performing projection exposure, a folding mirror may be provided between the digital mask 2 and the stage 6, and each alignment mark may be taken while the mirror is folded back. Each of the folding mirrors is disposed at a position where the light for exposure is not blocked.

However, in the device for performing contact exposure or proximity exposure, if the alignment mark is received by the digital mask 2, the parallax at the time of picking up the alignment mark is reduced, so that data having higher precision can be obtained. Correction The superiority.

Further, as described above, in the above embodiment, the contact exposure is performed by vacuum evacuation to improve the adhesion. The imaging of the alignment mark of the camera 7 is performed by the digital mask 2 and the workpiece W by vacuum evacuation. Come in a close state. Then, keeping the vacuum exhausted in a state of close contact, the mask pattern to which the correction data is applied is displayed on the digital mask 2 for exposure. Therefore, after the photographing of the camera 7, there is no possibility that the positional deviation of the workpiece W occurs and the correction data is formed incorrectly, and the technical configuration of the correction of the mask pattern of the alignment mark imaging becomes more significant.

Further, the improvement of the adhesion by vacuum evacuation is not essential in the invention of the present invention, as long as the digital mask 2 is brought into contact with the workpiece W. In this case, as long as the frictional force acts between the two, not only does one move, but the positional relationship between the two does not change, and the above effects can be obtained. However, since vacuum adsorption is performed, the frictional force is relatively high, so that the above effect has a more reliable surface.

The relationship between the dot pitch of the digital mask 2 and the resolution of the exposure is, for example, a case where the digital mask 2 having a dot pitch of about 30 μm is used for exposure in equal magnification (contact method or proximity method). Exposure to line and space at a level of 100 μm. A line width of about 100 μm is a grade used in most articles, and the level of lithography which is highly flexible at this level is significant.

Further, there is a case where a plurality of lithography is repeated for one workpiece W in a certain manufacturing process to form a pattern of a hierarchical structure. In this case, it is possible to adjust the next time in the lithography at the time of patterning. Patterning of lithography (patterning of the upper layer). That is, as shown enlarged in FIG. 4, another pattern may be formed in the pattern forming region WR of the workpiece W. The configuration of the embodiment can be optimized for such use. Specifically, data processing is performed by taking a specific portion of the pattern formed by the previous photolithography with a camera. In this case, it can be determined that the image forming position is selected at the position where the pattern of the previous photolithography is formed, and the XYθ correction data is calculated in the same manner as in the case of the workpiece W. Further, by ingesting a certain characteristic point, it is possible to determine the offset of the size of the formed pattern or to determine the deformation. In this case, similarly to the case of the workpiece W, the expansion correction data is calculated or the deformation data is created. The next exposure is performed in a state where the display position or shape of the mask pattern is corrected. In this way, since the pattern of each layer is formed in a state where the positional shift or the deformation is corrected, a more favorable pattern of the multilayer structure can be obtained.

Further, in the workpiece W such as a wafer, a singular point of a contour shape such as an orientation flat or a notch is provided. Therefore, the XYθ correction data can also be created by taking the singular point on the camera. Therefore, in the invention of the present invention, the imaging of the camera is a specific portion of the workpiece W which is made possible by the correction data.

However, as is apparent from the above description, the alignment mark is provided on the workpiece to pick up the alignment mark and is used for the correction of the mask data, and the data processing is easy, and the expansion correction and the like are also easily performed. At this point, the camera with the alignment mark is ideal.

1‧‧‧Light source

2‧‧‧Digital mask

3‧‧‧Transfer Department

4‧‧‧ Controller

5‧‧‧Optical Optics

6‧‧‧ platform

7‧‧‧ camera

8‧‧‧Exhaust system

21‧‧‧ Frame Department

31‧‧‧ moving into the side conveyor

32‧‧‧Removing side conveyor

33‧‧‧Hand in hand

34‧‧‧ Moved out

41‧‧‧ Processor

42‧‧‧Memory Department

43‧‧‧Import and Export Department

51‧‧‧ optical axis

60‧‧‧ platform origin

61‧‧‧Vacuum adsorption holes

62‧‧‧Mobile agencies

63‧‧‧Weighed sealing members

64‧‧‧ venting holes

71‧‧‧ optical axis

331, 341‧‧‧Hand drive mechanism

AM‧‧ Alignment mark

W‧‧‧Workpiece

Claims (11)

An exposure apparatus comprising: a light source that emits light including ultraviolet rays; a transmissive digital photomask; and a transport system that transports a workpiece to an irradiation position of light from a light source that passes through the digital mask; This is a specific part of the workpiece that is conveyed to the irradiation position of the light; and the controller, in addition, the digital mask has a plurality of pixels controlled by the controller, and each pixel is obtained: the ultraviolet light is turned off. In the state and the ON state in which the ultraviolet ray is blocked, the controller includes a memory unit that memorizes pattern data for displaying the mask pattern on the digital mask, and an output unit that is paired with the digital light. The mask outputs the pattern data, and the display of the mask pattern is performed on the digital mask, and a correction program is installed in the controller, so that the pattern data corrected according to the image data of the camera can be output from the output portion. The correction program includes a display position correction module for correcting the mask pattern on the digital mask according to the camera data of the specific part of the workpiece of the camera. Location. An exposure apparatus according to claim 1, wherein the foregoing A specific part of the workpiece is an alignment mark. The exposure apparatus of claim 2, wherein the plurality of alignment marks are provided, and the camera is a person who picks up each alignment mark. The exposure apparatus of claim 3, wherein the camera system is provided at a position at which each of the alignment marks can be ingested. The exposure apparatus of claim 3, wherein the correction program includes a expansion/expansion module that determines a display magnification of a mask pattern of the digital mask according to the image data of the alignment mark of the camera. The exposure apparatus of claim 3, wherein the correction program comprises: determining deformation of the workpiece according to the image data of the alignment mark of the camera, and the mask pattern is deformed according to the determination result. Deformation module. The exposure apparatus of claim 1, wherein the digital photomask has a light transmitting portion that transmits light of a wavelength of the camera, and the camera is placed in the transmitting portion that is transparent to the digital mask to be targeted The location of the aforementioned specific part. The exposure apparatus of claim 7, wherein the moving mechanism is configured to move the workpiece conveyed to the irradiation position or the digital mask to be in a state in which the workpiece is in contact with the digital mask or The predetermined gap is in the opposite direction. An exposure apparatus according to claim 1, wherein the foregoing The specific portion of the workpiece is a specific portion of the pattern formed by photolithography that has been performed. An exposure method using an exposure apparatus according to any one of the first to ninth aspects of the invention, wherein the exposure apparatus includes a platform disposed at an irradiation position of the light, and a platform a moving mechanism for moving the platform or the digital mask to move the digital mask to the workpiece while the workpiece is placed, and having a photographing step of transmitting the digital mask to the workpiece and transmitting the digital image a mask for performing photographing of a specific portion of the workpiece by using the camera; a correcting step of performing the correction program according to image data acquired in the photographing step; and an exposure step of being corrected by the correction program The pattern data is such that the mask pattern is displayed on the digital mask, and the workpiece is exposed. During the period from the photographing step to the end of the exposure step, the position of the digital mask that is in contact with the workpiece and the positional relationship between the two does not change. . An exposure method using an exposure apparatus according to any one of the first to ninth aspects of the invention, wherein the exposure apparatus includes a platform disposed at an irradiation position of the light, and a platform a moving mechanism for moving the platform or the digital mask to bring the digital mask into contact with the workpiece while the workpiece is placed, and the digital mask and the workpiece in a state where the digital mask is in contact with the workpiece An exhaust system in which a space is evacuated and the two are in close contact with each other, characterized in that: a photographing step is performed in which a space between the photomask and the workpiece is vacuum-exhausted and the two are in close contact with each other a digital photomask for performing photographing of a specific portion of the workpiece by using the camera; a correcting step of performing the correction program according to the image data obtained in the photographing step; and an exposing step by using the correction program The modified pattern data is used to display the mask pattern on the digital reticle, and the workpiece is exposed. During the period from the photographing step to the end of the exposure step, the space between the digital reticle and the workpiece is evacuated by vacuum. The status of the post will continue.