JP6137323B2 - Exposure equipment - Google Patents

Description

  The present invention relates to an exposure apparatus used for manufacturing semiconductor devices, printed boards, LCDs, and the like. In particular, the present invention relates to an exposure apparatus that aligns an alignment mark provided on the back surface of a workpiece and an alignment mark of a mask and exposes a mask pattern on the workpiece.

  Another pattern with a fixed positional relationship with respect to the singular point on the other surface of the workpiece, with reference to a singular point such as a workpiece alignment mark, circuit or other workpiece pattern provided on one surface of the workpiece. May form. That is, this is a case where another pattern having a fixed positional relationship with the work alignment mark is formed on the surface opposite to the surface of the work provided with the work alignment mark.

  The alignment (alignment) between the mask and the workpiece is usually performed by detecting the position of the through hole and the position of the mask pattern by an alignment means (for example, an alignment microscope) so that they match. However, since the workpiece is generally opaque, when forming another pattern on the surface opposite to the surface provided with singular points such as workpiece alignment marks, patterns or holes provided on one surface of the workpiece, A singular point provided on one surface of the workpiece cannot be detected from the other surface (surface to be exposed) side of the workpiece. In general, photosensitive materials applied for exposure are opaque, and even if the workpiece is a transparent material, it can detect singular points such as alignment marks, patterns and holes from the exposed surface side. It is difficult.

  In order to solve such a problem, for example, Patent Document 1 discloses an exposure apparatus in which a mask alignment mark corresponding to a work alignment mark is provided in a portion outside the work size. Then, using a two-field microscope having two observation parts, or two microscopes whose relative positions do not change, and fixing with a fixing member that supports the microscope so as to match the distance between the workpiece alignment mark and the mask alignment mark Thus, a back surface alignment function that can detect the workpiece alignment mark and the mask alignment mark at the same time and align the mask and the workpiece is provided.

JP-A-11-340120

  The exposure apparatus disclosed in Patent Document 1 has a two-field microscope having two observation units. The distance between the two fields of the microscope or the distance between the two microscopes is mounted on the microscope. A fixed distance is maintained depending on the length of the fixing member. Therefore, when a large temperature change occurs in the surrounding environment of the exposure apparatus, the length of the fixing member fluctuates due to thermal expansion, so the distance between the microscopes cannot be maintained at a constant distance, and There was a problem that it was impossible to align the mask and the workpiece.

  The present invention has been made in view of such circumstances, and even an alignment mark provided on the back surface of the workpiece can be reliably aligned with the alignment mark of the mask, and the mask pattern can be accurately aligned with the workpiece. It is an object of the present invention to provide an exposure apparatus that exposes the top.

In order to achieve the above object, an exposure apparatus according to the present invention includes a mask provided with a mask alignment mark, a mask holder for holding the mask, and a surface opposite to the surface facing the surface provided with the mask alignment mark. A stage on which a workpiece having a workpiece alignment mark is mounted and fixed, a stage driving device for moving the stage and adjusting the relative position between the mask and the workpiece, the mask alignment mark, and the workpiece alignment mark An exposure apparatus comprising: an imaging apparatus having a fixed position in a height direction , wherein the stage is configured to capture a size of the workpiece when imaging the workpiece alignment mark of the mounted workpiece. An optical component that reflects light an odd number of times inside so that an image is formed at an outer position For example, the stage driving device, based on the image formed through the optical component is intended for aligning the workpiece alignment mark and the mask alignment mark, the work at the time of imaging of the workpiece alignment marks Is a thickness A, and a distance between the workpiece and the mask is a distance B, a distance C between the stage and the mask at the time of imaging the mask alignment mark is a thickness A and a distance B. The stage moves so as to be half of the sum of the above .

In the above configuration, when imaging the workpiece alignment mark of the mounted workpiece, the light is internally reflected an odd number of times so that an image is formed at a position outside the workpiece size. Therefore, since the image of the work alignment mark formed at a position outside the work size is an upright image, the mask alignment mark and the work alignment mark can be aligned with high accuracy. In addition, since the image of the mask alignment mark and the image of the work alignment mark formed by the optical component can be adjusted using the stage driving device so as to be at the same position, the alignment accuracy deteriorates due to the temperature change of the surrounding environment. There is no fear. Further, since the distance C between the stage and the mask at the time of imaging the mask alignment mark is (thickness A + distance B) / 2, even if the position in the height direction of the imaging apparatus is fixed, the focus is increased. Matching is easy and high quality images can be taken.

  In the exposure apparatus according to the present invention, the optical component is preferably a columnar prism having a pentagonal cross-sectional shape.

  In the above configuration, since the optical component is a prismatic prism having a pentagonal cross-sectional shape, an image formed at a position outside the size of the workpiece can be made an upright image by reflecting light an odd number of times inside. it can. Therefore, it is possible to align the mask alignment mark and the work alignment mark with high accuracy.

  In the exposure apparatus according to the present invention, the optical component is preferably configured by combining a plurality of columnar prisms having a polygonal cross-sectional shape.

  In the above configuration, the optical component is configured by combining a plurality of columnar prisms having a polygonal cross-sectional shape, and reflects an image an odd number of times to thereby form an image formed at a position outside the workpiece size. It can be an erect image. Therefore, it is possible to align the mask alignment mark and the work alignment mark with high accuracy.

  In the exposure apparatus according to the present invention, the optical component is preferably configured by combining a prismatic prism having a polygonal cross section and a mirror.

  In the above configuration, the optical component is configured by combining a prismatic prism having a polygonal cross section and a mirror, so that it can reflect light an odd number of times inside and is formed at a position outside the workpiece size. The image that is made can be an erect image. Therefore, it is possible to align the mask alignment mark and the work alignment mark with high accuracy.

According to the above configuration, when imaging the workpiece alignment mark of the mounted workpiece, the light is internally reflected an odd number of times so that an image is formed at a position outside the workpiece size. Therefore, since the image of the work alignment mark formed at a position outside the work size is an upright image, the mask alignment mark and the work alignment mark can be aligned with high accuracy. In addition, since the image of the mask alignment mark and the image of the work alignment mark formed by the optical component can be adjusted using the stage driving device so as to be at the same position, the alignment accuracy deteriorates due to the temperature change of the surrounding environment. There is no fear. Further, since the distance C between the stage and the mask at the time of imaging the mask alignment mark is (thickness A + distance B) / 2, even if the position in the height direction of the imaging apparatus is fixed, the focus is increased. Matching is easy and high quality images can be taken.

It is sectional drawing which shows the structure of the exposure apparatus which concerns on embodiment of this invention. It is sectional drawing of the columnar prism with which the stage of the exposure apparatus which concerns on embodiment of this invention is equipped. It is sectional drawing of the other optical component with which the stage of the exposure apparatus which concerns on embodiment of this invention is equipped. It is sectional drawing for demonstrating the state at the time of the imaging of the mask alignment mark of the exposure apparatus which concerns on embodiment of this invention. It is sectional drawing for demonstrating the state at the time of imaging of the workpiece alignment mark of the exposure apparatus which concerns on embodiment of this invention.

  Hereinafter, an exposure apparatus according to an embodiment of the present invention will be specifically described with reference to the drawings.

  An exposure apparatus according to an embodiment of the present invention captures an image of a workpiece alignment mark provided on the back surface of a workpiece to be imaged using an imaging device with a fixed height for imaging, and mask alignment mark of a mask And align. The exposure apparatus according to the present embodiment includes a pair of imaging devices at both ends for imaging a workpiece alignment mark provided on the back surface of a workpiece mounted during exposure. FIG. 1 is a sectional view showing the arrangement of an exposure apparatus according to an embodiment of the present invention.

  In FIG. 1, an exposure apparatus 1 according to an embodiment of the present invention holds a pair of imaging apparatus 11, a mask 13 provided with a mask pattern (not shown) and a mask alignment mark 131, and the mask 13. A workpiece having a workpiece alignment mark 141 on the surface 145 (the back surface of the workpiece 14) opposite to the mask holder 12 and the surface 135 (the surface facing the workpiece 14) on which the mask pattern and the mask alignment mark 131 are provided. 14 includes a stage 15 on which 14 is mounted and fixed, and stage driving devices 16 and 17 that adjust the relative position between the mask 13 and the workpiece 14 by moving the stage 15. For the mask alignment mark 131, the mask pattern itself may be used as the alignment mark.

  The imaging device 11 is a camera whose position in the height direction is fixed. It is preferable that the imaging device 11 is an integral type provided with illumination around the lens. This is because the imaging device 11 can be made compact. Further, the imaging device 11 is arranged so as to capture the workpiece alignment mark 141 outside the size of the workpiece 14, not directly above the mask alignment mark 131 of the mask 13. The image formation is realized by providing an optical component described later.

  The mask 13 is preferably a partly transparent plate, and a mask pattern (not shown) and a mask alignment mark 131 are provided on a surface 135 facing the workpiece 14. By aligning the position of the mask alignment mark 131 with the position of the work alignment mark 141 of the work 14, the mask pattern (circuit pattern) can be correctly exposed to a desired position on the work 14.

  The workpiece 14 is mounted on the stage 15 and fixed. The relative position between the mask 13 and the workpiece 14 can be adjusted by moving the stage 15 by the stage driving devices 16 and 17. For example, the stage driving device 16 moves the stage 15 in the vertical direction to adjust the distance between the mask 13 and the workpiece 14. The stage driving device 17 moves the stage 15 in the front-rear and left-right directions or rotates the stage 15 to adjust the horizontal position of the mask 13 and the work 14.

  The stage 15 includes an optical component that reflects light an odd number of times inside so that an image is formed at a position outside the size of the workpiece 14. In the present embodiment, a columnar prism 20 having a pentagonal cross section is provided as an optical component. By reflecting light within the columnar prism 20 an odd number of times, an image is formed as an erect image. Therefore, the mask alignment mark 131 of the mask 13 and the work alignment mark 141 of the work 14 can be aligned with high accuracy. Examples of the material of the columnar prism 20 include borosilicate glass and synthetic quartz. The light reflected inside the columnar prism 20 may be visible light or infrared light.

  FIG. 2 is a cross-sectional view of the columnar prism 20 provided in the stage 15 of the exposure apparatus 1 according to the embodiment of the present invention. As shown in FIG. 2, the light is reflected an odd number of times (three times in FIG. 2) inside the columnar prism 20. Thereby, the reflected image is formed as an erect image at a position outside the size of the work 14.

  The reason for forming the erect image is to facilitate alignment. When light is provided with a columnar prism that reflects an even number of times (for example, twice), the formed image is an inverted image. Since the image is formed as an inverted image, the direction in which the image is displaced is opposite to the direction in which the stage 15 is actually moved to correct the displacement. Therefore, it is difficult to correctly align only by moving the stage 15.

  On the other hand, when the formed image is an erect image, the direction in which the image is shifted coincides with the direction in which the shift is corrected by moving the stage 15. It can be aligned correctly.

  Further, the optical component is not limited to the columnar prism 20 having a pentagonal cross-sectional shape, as long as it can reflect light an odd number of times inside. FIG. 3 is a cross-sectional view of another optical component provided in the stage 15 of the exposure apparatus 1 according to the embodiment of the present invention.

  3A is a cross-sectional view of a composite prism in which a columnar prism 20a having a pentagonal cross-sectional shape, a columnar prism 20b having a rectangular cross-sectional shape, and a columnar prism 20c having a triangular cross-sectional shape are combined. Is shown. In FIG. 3A, since light is not reflected inside the columnar prism 20b having a rectangular cross-sectional shape, the position where the image is formed can be adjusted by adjusting the length of the columnar prism 20b. . The columnar prisms 20a, 20b, and 20c may be bonded with a transparent optical adhesive, or the columnar prisms 20a, 20b, and 20c may be melt bonded.

  FIG. 3B is a cross-sectional view of an optical component in which a columnar prism 20a having a pentagonal cross-sectional shape and a reflection mirror (mirror body) 20d are combined. In FIG. 3B, since the right end surface of the columnar prism 20a is configured to be perpendicular to the surface of the workpiece 14, the position of the image is formed by adjusting the position of the reflecting mirror 20d. It can be adjusted.

  Hereinafter, the alignment process in the exposure apparatus 1 having the above-described configuration will be described. FIG. 4 is a cross-sectional view for explaining a state during imaging of mask alignment mark 131 of exposure apparatus 1 according to the embodiment of the present invention.

  As shown in FIG. 4, the pair of imaging devices 11 are fixed at positions in the height direction. Therefore, focusing of the mask alignment mark 131 of the mask 13 to be imaged and the work alignment mark 141 of the work 14 is performed by moving the stage 15 in the vertical direction.

  Specifically, first, the thickness A (see FIG. 5) of the workpiece 14 is measured. The distance between the mask 13 and the workpiece 14 at the time of exposure is defined as an exposure gap B (see FIG. 5). The design value itself may be adopted as the thickness A of the workpiece 14.

  As shown in FIG. 4, the mask imaging gap C, which is the distance between the mask 13 and the stage 15 at the time of imaging the mask alignment mark 131, is half of the sum of the thickness A of the workpiece 14 and the exposure gap B. The height of the stage 15 is adjusted by the stage driving device 16 so as to be. In this way, even if the position of the imaging device 11 in the height direction is fixed by adjusting the height of the stage 15 so that the mask imaging gap C becomes (A + B) / 2, the mask The alignment mark 131 can be focused. Therefore, it is possible to align with high accuracy.

  The imaging device 11 images the mask alignment mark 131 in a state in which the height of the stage 15 is adjusted and focused, and stores information regarding the position of the captured mask alignment mark 131. Specifically, based on the captured image, the position information of the mask alignment mark 131 is extracted and stored.

  Next, the work 14 is mounted on the stage 15 and fixed. FIG. 5 is a cross-sectional view for explaining a state during imaging of the work alignment mark 141 of the exposure apparatus 1 according to the embodiment of the present invention. Similar to FIG. 4, focusing of an image to be captured is performed by moving the stage 15 in the vertical direction.

  Specifically, the distance between the mask 13 and the stage 15 at the time of imaging the workpiece alignment mark 141 is A + B, that is, the distance between the mask 13 and the workpiece 14 is equal to the exposure gap B. The stage 15 is moved up and down by the stage driving device 16 to adjust the height. In a state where the height of the stage 15 is adjusted and focused, the imaging device 11 images the work alignment mark 141 and extracts and stores position information of the work alignment mark 141.

  Based on the stored position information of the mask alignment mark 131 and the position information of the workpiece alignment mark 141, the stage 15 is moved in the front-rear and left-right directions and / or rotated by the stage driving device 17, so that both positions are Match. Specifically, the stage 15 is moved so that the position information of the work alignment mark 141 matches the position information of the mask alignment mark 131.

  Thereafter, the workpiece 14 is imaged again to acquire position information of the workpiece alignment mark 141, and the stage 15 is moved so that the position information of the workpiece alignment mark 141 acquired again matches the position information of the mask alignment mark 131. Let By repeating these operations, both pieces of positional information are made to coincide. By performing exposure in a state where the positional information of both is matched, the mask pattern (circuit pattern) can be accurately exposed on the work 14.

  As described above, according to the present embodiment, when imaging the workpiece alignment mark 141 of the mounted workpiece 14, the light is internally reflected an odd number of times so that an image is formed at a position outside the size of the workpiece 14. . Therefore, since the image of the workpiece alignment mark 141 formed at a position outside the size of the workpiece 14 is an upright image, the mask alignment mark 131 of the mask 13 and the workpiece alignment mark 141 of the workpiece 14 are aligned with high accuracy. It becomes possible to do. Further, since the image of the mask alignment mark 131 and the image of the work alignment mark 141 formed by the columnar prism 20 can be adjusted using the stage driving device 16 so as to be at the same position, the temperature change of the surrounding environment, etc. Therefore, there is no possibility that the alignment accuracy deteriorates.

  In addition, it cannot be overemphasized that embodiment mentioned above can be changed in the range which does not deviate from the meaning of this invention. For example, the optical component is not limited to a prismatic prism having a cross-sectional shape or a combination of prisms having different shapes, and a plurality of mirrors can be used as long as light can be reflected an odd number of times inside. You may comprise combining.

  In FIG. 1, the imaging device 11 and the optical component 20 are paired, but the imaging device 11 and the optical component 20 may each be a single unit. The imaging device 11 is paired because, when the size of the workpiece 14 is large, the workpiece alignment mark 141 of the workpiece 14 and the mask alignment mark 131 of the mask 13 are imaged and the θ accuracy of the alignment (rotation direction) In order to increase the accuracy). When the size of the workpiece 14 is small and the workpiece alignment mark 141 and the mask alignment mark 131 have a shape capable of detecting an angle (for example, a square shape or a cross shape), the imaging device 11 and the optical component 20 are used alone. There may be.

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 11 Imaging device 12 Mask holder 13 Mask 14 Work 15 Stage 16, 17 Stage drive device 20, 20a, 20b, 20c Columnar prism (optical component)
20d Reflection mirror (mirror body)
131 Mask alignment mark 141 Work alignment mark

Claims (4)

A mask provided with a mask alignment mark;
A mask holder for holding the mask;
A stage for mounting and fixing a workpiece having a workpiece alignment mark on a surface opposite to the surface facing the surface provided with the mask alignment mark;
A stage driving device for moving the stage and adjusting a relative position between the mask and the workpiece;
An exposure apparatus that images the mask alignment mark and the workpiece alignment mark , and an imaging apparatus having a fixed position in a height direction ,
The stage includes an optical component that reflects light an odd number of times internally so that an image is formed at a position outside the size of the workpiece when imaging the workpiece alignment mark of the mounted workpiece.
The stage drive device aligns the mask alignment mark and the work alignment mark based on an image formed through the optical component ,
When the thickness of the workpiece at the time of imaging the workpiece alignment mark is thickness A and the distance between the workpiece and the mask is distance B, the space between the stage and the mask at the time of imaging the mask alignment mark The exposure apparatus is characterized in that the stage moves so that the distance C is half the sum of the thickness A and the distance B.   The exposure apparatus according to claim 1, wherein the optical component is a columnar prism having a pentagonal cross-sectional shape.   The exposure apparatus according to claim 1, wherein the optical component is configured by combining a plurality of columnar prisms having a polygonal cross-sectional shape.   The exposure apparatus according to claim 1, wherein the optical component is configured by combining a columnar prism having a polygonal cross-sectional shape and a mirror body.

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