JP2005129786A - Aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner which is capable of restraining an equipment cost from increasing and very easily and precisely aligning a mask pattern that is projected for exposure to both the sides of a substrate as an object of exposure. <P>SOLUTION: An upper projector 4 and a lower projector 5 are provided on the surface side and backside of a substrate support stage 3 which supports the substrate 2 as an object of exposure. Aligning optical members 22 and 22 are provided in the vicinity of the substrate support stage 3, the upper projector 4 and the lower projector 5 irradiate the substrate 2 through the intermediary of a surface photomask 14 and a backside photomask 15 with light, respectively, and the images of aligning marks 14a, 14a and 15a, 15a are guided to mark detectors 21 and 21 and photographed. The mask support stages 12 and 12 are driven and controlled by a control unit 31 on the basis of the detection signals outputted from the mark detectors 21 and 21 to align the surface photomask 14 and the backside photomask 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exposure apparatus that projects a mask pattern formed on a photomask from both sides of a substrate to be exposed.

  2. Description of the Related Art Conventionally, in an exposure apparatus used for manufacturing a semiconductor such as an IC, exposure is performed by irradiating light through a photomask having a mask pattern formed on an exposure target substrate coated with a photosensitive agent. An exposure apparatus that transfers a mask pattern onto a substrate is used.

  As this type of exposure apparatus, a double-sided exposure type exposure apparatus that projects a mask pattern formed on a photomask from both sides of a substrate to be exposed is known (for example, see Patent Document 1).

JP 2002-182397 A

  By the way, in a double-side exposure type exposure apparatus, it is necessary to align and expose a mask pattern projected on both sides of a substrate to be exposed with high accuracy. Therefore, develop the exposed substrate with the mask pattern exposed on both sides, measure the error of the pattern formed on the exposed substrate with a double-sided microscope, and adjust the position of the photomask based on the measurement result Although the alignment is performed, this alignment operation is extremely complicated and requires a lot of labor and time. Moreover, in order to align in this way, the chemical processing equipment which develops a to-be-exposed board | substrate must be installed in the vicinity of exposure equipment, an installation becomes large and an installation expense will increase.

  The present invention has been made in view of the above-described circumstances, and its object is to extremely easily and highly accurately align mask patterns to be exposed on both surfaces of a substrate to be exposed without incurring an increase in equipment costs. It is an object of the present invention to provide an exposure apparatus that can be performed in the same manner.

  In order to achieve the above object, an exposure apparatus according to the present invention is characterized by the following (1) to (3).

  (1) Projectors for irradiating light through a photomask supported by a mask support stage are respectively installed on both sides of a substrate support stage to be exposed for supporting the substrate to be exposed. An exposure apparatus for projecting and transferring a mask pattern on both sides of an optical member, and detecting an optical member for guiding light from each projector in the same direction and light from each projector guided by the optical member And a position difference of a photomask of each projector can be detected based on a detection signal from the detector.

  (2) The exposure apparatus according to (1), further comprising a control unit that controls the mask support stage based on a detection signal from the detector and aligns the photomasks on both sides. It is characterized by that.

  (3) In the exposure apparatus according to (1) or (2), the optical member includes a half mirror that separates light from the projector into reflected light and transmitted light.

  According to the exposure apparatus described in (1) above, the detector detects the light from each projector guided by the optical member. Based on the detection signal from the detector, for example, Images from the projectors can be displayed on a display device, and the mask support stage can be driven based on the displayed images to align the photomask. This eliminates the need for a development processing facility for developing the substrate to be exposed for alignment, and extremely aligns the mask pattern to be exposed on both surfaces of the substrate to be exposed without increasing the equipment cost. It can be performed easily and with high accuracy.

  According to the exposure apparatus described in (2) above, the control unit controls the mask support stage based on the detection signal from the detector to automatically align the photomasks on both sides. Further alignment can be facilitated.

  According to the exposure apparatus described in (3) above, since an optical member made of a half mirror is simply used, highly accurate alignment can be easily realized without increasing the cost.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(First embodiment)
First, the exposure apparatus according to the first embodiment will be described.

  FIG. 1 is a schematic diagram showing the overall configuration of a first embodiment of the exposure apparatus according to the present invention, and FIG. 2 is an enlarged view showing the configuration of the alignment portion of the photomask in the exposure apparatus of FIG.

  As shown in FIG. 1, an exposure apparatus 1 is a double-sided exposure type exposure apparatus that projects a mask pattern from both sides of a substrate to be exposed. The exposure apparatus 1 includes an exposure substrate support stage 3 that supports an exposure substrate 2. An upper projector 4 and a lower projector 5 are provided above and below the exposure substrate support stage 3, respectively. It has been.

  Each of the upper projector 4 and the lower projector 5 includes a light projecting lens 11, a mask support stage 12, and a light source 13 in order from the exposed substrate support stage 3 side. The mask support stage 12 of the upper projector 4 supports the front photomask 14, and the mask support stage 12 of the lower projector 5 supports the back photomask 15.

  Each mask support stage 12 supports the front photomask 14 or the back photomask 15 so as to be movable in two directions (XY directions) orthogonal to each other in a horizontal plane and to be rotatable in a rotation direction (θ direction). The front photomask 14 and the back photomask 15 supported by the mask support stages 12 and 12 are provided with alignment marks 14a and 14a and alignment marks 15a and 15a in the vicinity of both sides, respectively.

  In this exposure apparatus 1, light from the light sources 13 and 13 of the upper projector 4 and the lower projector 5 passes through the front photomask 14 or the back photomask 15, and further passes through the light projection lenses 11 and 11. The mask pattern is transferred onto both surfaces of the substrate 2 to be exposed, which is irradiated on the front and back of the substrate 2 to be exposed supported by the substrate support stage 3 to be exposed.

  This exposure apparatus 1 is provided with mark detectors 21 and 21 comprising CCD cameras in the vicinity of both sides of the substrate support stage 3 to be exposed. In addition, alignment optical members 22 and 22 can be provided in the vicinity of both side portions of the substrate support stage 3 instead of the substrate 2 when the front photomask 14 and the back photomask 15 are aligned. It is like that. As shown in FIG. 2, the alignment optical members 22 and 22 are made of a plate-like half mirror (here, a substance having a lower light reflectance than the base material on the upper surface of a substantially transparent base material (eg, glass)). The reflectance of the material to be coated is not limited to 50%, and may be a different value if applicable to the present invention. , 22, a part of the light irradiated from the front and back is reflected and the rest is transmitted.

  Note that the alignment marks 14a and 14a and the alignment marks 15a and 15a are in exactly the same positions on the front photomask 14 and the back photomask 15, respectively, and the alignment between the front photomask 14 and the back photomask 15 is actually performed. Even in a state where the light is incident, the light incident on the alignment optical members 22 and 22 from the back photomask 15 side is refracted. Therefore, strictly speaking, the alignment marks 14a and 14a and the alignment marks 15a and 15a are misaligned. The state and the mark detectors 21 and 21 may be observed. Therefore, in order to eliminate such inconveniences, conditions such as the thickness of the alignment optical members 22 and 22, the refractive index, the thickness of the substrate 2 to be exposed, and the like are taken into consideration. The alignment marks 14a and 14a and the alignment marks 14a and 14a are observed so as to be observed by the mark detectors 21 and 21 when the alignment marks 14a and the alignment marks 15a are aligned in a state where the alignment is actually performed. The positional relationship between the alignment marks 15a and 15a is preferably adjusted in advance.

  Each of the alignment optical members 22 and 22 is configured such that it can be advanced and retracted by a conveying device (not shown) while being held by a holding member (not shown). However, instead of such a configuration, for example, an operator may install a plate having the same dimensions as the substrate 2 to be exposed and having at least a necessary portion constituted by a half mirror when necessary.

  Further, as shown in FIG. 3, the exposure apparatus 1 includes a control unit 31, and mark detectors 21 and 21 are connected to the control unit 31. The control unit 31 is connected to the respective mask support stages 12 and 12 of the upper projector 4 and the lower projector 5. The control unit 31 is based on detection signals from the mark detectors 21 and 21. Then, a control signal is transmitted to the mark support stages 12 and 12, and the drive of the mark support stages 12 and 12 is controlled.

  Next, in the exposure apparatus 1 having the above-described configuration, a case where the front photomask 14 and the back photomask 15 supported on the mask support stages 12 and 12 of the upper projector 4 and the lower projector 5 are aligned will be described.

  First, the alignment optical members 22 and 22 are supported at predetermined positions in place of the exposure substrate 2 on the exposure substrate support stage 3 that supports the exposure substrate 2.

  In this state, exposure by the upper projector 4 and the lower projector 5 is performed. In this way, the light from the light sources 13 and 13 of the upper projector 4 and the lower projector 5 is transmitted through the front photomask 14 or the back photomask 15, and is further exposed via the light projection lenses 11 and 11. Irradiation from the front and back toward the substrate support stage 3.

  Then, the alignment optical members 22 and 22 are irradiated with the light of the images of the alignment marks 14a and 14a of the front photomask 14 and the light of the images of the alignment marks 15a and 15a of the back photomask 15, respectively.

  As a result, the image of the alignment marks 14a and 14a of the front photomask 14 reflected by the alignment optical members 22 and 22 and the alignment marks 15a and 15a of the back photomask 15 transmitted through the alignment optical members 22 and 22 are obtained. The light of the image 15a is guided to the mark detectors 21 and 21.

  The mark detectors 21, 21 convert the images of the alignment marks 14 a, 14 a, 15 a, 15 a into electrical signals and output them as detection signals to the control unit 31, which controls the mark detectors 21, 21. Based on the detection signal, a control signal is output to each mask support stage 12 so that the positions of the alignment marks 14a, 14a, 15a, 15a coincide with each other, and the positions of the front photomask 14 and the back photomask 15 are set. adjust.

  Specifically, calculation of the center positions of the alignment marks 14a, 14a, 15a, and 15a at each of the two locations and the respective alignment marks by an appropriate arithmetic processing device and software program built in the control unit 31. The amount of movement of the mask support stages 12 and 12 necessary for eliminating the deviation of the center positions of 14a, 14a, 15a and 15a is calculated. Then, as shown in FIGS. 4A and 4B, when the alignment marks 14a, 14a of the front photomask 14 and the alignment marks 15a, 15a of the back photomask 15 are misaligned. (The state of FIG. 4A), the control unit 31 controls each mask support stage 12, and the alignment mark 15a of the back photomask 15 is placed at the center of each of the alignment marks 14a, 14a of the front photomask 14. 15a are arranged (the state shown in FIG. 4B).

  Note that the specific alignment method between the alignment marks 14a and 15a is not limited to the case where the centers coincide with each other as described above. For example, the alignment marks 14a and 15a are arranged at a predetermined position. The corners may be matched. Further, the shapes of the alignment marks 14a, 14a, 15a and 15a are not limited to those shown in FIGS. 4A and 4B, but are within the field of view of the CCD camera which is the mark detectors 21 and 21. Other patterns may be used as long as they can be accommodated and the shift amount of the front photomask 14 and back photomask 15 can be specified. As a method of alignment, for example, reference positions such as the center position of the visual field of the CCD camera which is the mark detectors 21 and 21 are determined, and the center positions of the alignment marks 14a, 14a, 15a, and 15a are respectively determined. Try to match. However, instead of this, only one of the mask support stages 12 and 12 is movable, and the alignment marks 14a and 14a or 15a and 15a corresponding to the mask support stage 12 on the fixed side are used as a reference. The alignment marks 15a, 15a or 14a, 14a corresponding to the mask support stage 12 may be aligned.

  After aligning the front photomask 14 and the back photomask 15 as described above, the alignment optical members 22 and 22 used for alignment are removed from the exposure substrate support stage 3 to support the exposure substrate 2, A mask pattern is exposed on both surfaces of the substrate 2 to be exposed by the upper projector 4 and the lower projector 5.

  Here, since the images of the mask pattern irradiated from each of the upper projector 4 and the lower projector 5 are aligned with high accuracy, the exposure substrate 2 is aligned with both surfaces with high accuracy. The mask pattern is transferred.

  As described above, according to the exposure apparatus 1 of the above embodiment, the mark detectors 21 and 21 detect the light from the upper projector 4 and the lower projector 5 guided by the alignment optical members 22 and 22, and these are detected. Based on detection signals from the mark detectors 21, 21, the control unit 31 can control the mask support stages 12, 12 to automatically align the front photomask 14 and the back photomask 15.

  This eliminates the need for development processing equipment for developing the exposed substrate 2 for positioning, and makes it possible to position the mask pattern exposed on both surfaces of the exposed substrate 2 without increasing the equipment cost. It can be performed easily and with high accuracy.

  In addition, since the alignment optical members 22 and 22 composed of half mirrors are simply used, highly accurate alignment can be easily realized without increasing the cost.

(Second Embodiment)
Next, a second embodiment of the exposure apparatus according to the present invention will be described. The same structural parts as those in the first embodiment of the exposure apparatus described above are denoted by the same reference numerals, and description thereof is simplified or omitted.

  FIG. 5 is a schematic view showing the overall configuration of the second embodiment of the exposure apparatus according to the present invention, and FIG. 6 is an enlarged view showing the configuration of the alignment portion of the photomask in the exposure apparatus of FIG.

  As shown in FIG. 5, in this exposure apparatus 1A, the irradiation light irradiated to the to-be-exposed board | substrate 2 from the light projection lenses 11 and 11 of the upper projector 4 and the lower projector 5 is made into parallel light, and is irradiated perpendicularly. The In the exposure apparatus 1A, when aligning the front photomask 14 and the back photomask 15, prism-shaped alignment optical members 41, 41 having a triangular shape in side view are used.

  As shown in FIG. 6, each alignment optical member 41 has a coating 41a, coating 41a, which is substantially transparent and has a lower reflectance than the prism body on the two surfaces on which light is incident from the upper projector 4 and the lower projector 5, respectively. 41a, which guides the irradiation light from the upper projector 4 and the lower projector 5 to the sides, and the mark detector 21 is disposed on the side of each alignment optical member 41.

  Even when the front photomask 14 and the back photomask 15 are aligned in the exposure apparatus 1A, the substrate 2 to be exposed is first placed on the substrate support stage 3 that supports the substrate 2 to be exposed as described above. Instead, the alignment optical members 41 and 41 are supported at predetermined positions, and exposure by the upper projector 4 and the lower projector 5 is performed.

  In this way, the light from the light sources 13 and 13 of the upper projector 4 and the lower projector 5 is transmitted through the front photomask 14 or the back photomask 15, and further through the projection lenses 11 and 11. The light is irradiated from the front and back as parallel light toward the exposure substrate support stage 3.

  Then, the alignment optical members 41 and 41 are irradiated with the light of the image of the alignment marks 14a and 14a of the front photomask 14 and the light of the image of the alignment marks 15a and 15a of the back photomask 15, respectively. It is guided toward the detectors 21 and 21.

  The mark detectors 21, 21 convert the images of the alignment marks 14 a, 14 a, 15 a, 15 a into electrical signals and output them as detection signals to the control unit 31, which controls the mark detectors 21, 21. Based on the detection signal, a control signal is output to each mask support stage 12 so that the positions of the alignment marks 14a, 14a, 15a, 15a coincide with each other, and the positions of the front photomask 14 and the back photomask 15 are set. adjust. Thereby, the front photomask 14 and the back photomask 15 are aligned, and the mask pattern aligned with high accuracy is transferred onto both surfaces of the substrate 2 to be exposed.

  In the case of the exposure apparatus 1A of the second embodiment, the mark detectors 21 and 21 detect the light from the upper projector 4 and the lower projector 5 guided by the alignment optical members 41 and 41. Based on detection signals from the mark detectors 21, 21, the control unit 31 can control the mask support stages 12, 12 to automatically align the front photomask 14 and the back photomask 15.

  This eliminates the need for development processing equipment for developing the exposed substrate 2 for positioning, and makes it possible to position the mask pattern exposed on both surfaces of the exposed substrate 2 without increasing the equipment cost. It can be performed easily and with high accuracy.

  The present invention is not limited to the above-described embodiments, and modifications, improvements, etc. can be made as appropriate. In addition, the material, shape, dimension, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  In the first embodiment and the second embodiment, the front photomask is corrected by correcting the positional deviation between the center positions of the images of the alignment marks 14a, 14a, 15a, 15a of the front photomask 14 and the back photomask 15. 14 and the back photomask 15 are aligned, but a laser beam may be irradiated through the front photomask 14 and the back photomask 15 so that these laser beams coincide (ie overlap).

  In the first embodiment and the second embodiment, the controller 31 controls the mask support stages 12 and 12 based on the detection results from the mark detectors 21 and 21 to control the front photomask 14 and the back photomask. 15, for example, images taken by the mark detectors 21, 21 are displayed on a display device, and the positions of the alignment marks 14 a, 14 a, 15 a, 15 a are determined based on this display. The operator may operate the mask support stages 12 and 12 so as to match.

1 is a schematic diagram showing an overall configuration of a first embodiment of an exposure apparatus according to the present invention. It is an enlarged view which shows the structure of the alignment part of the photomask in the exposure apparatus of FIG. It is a block diagram for demonstrating the control system of exposure apparatus. It is explanatory drawing for demonstrating the method of alignment. It is the schematic which shows the whole structure of 2nd Embodiment of the exposure apparatus which concerns on this invention. It is an enlarged view which shows the structure of the position alignment part of the photomask in the exposure apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A exposure apparatus 2 Exposed substrate 3 Exposed substrate support stage 4 Upper projector (projector)
5 Downward projector (projector)
12 Mask support stage 14 Front photomask (photomask)
15 Back photomask (photomask)
21 Mark detector (detector)
22, 41 Positioning optical member (optical member)
31 Control unit

Claims (3)

Projectors for irradiating light through photomasks supported by a mask support stage are installed on both sides of the substrate support stage for supporting the substrate to be exposed, respectively. An exposure apparatus that projects and transfers a mask pattern,
An optical member that guides the light from each projector in the same direction; and a detector that detects the light from each projector guided by the optical member, and based on a detection signal from the detector, An exposure apparatus characterized in that a positional shift of a photomask of a projector can be detected.   2. The exposure apparatus according to claim 1, further comprising a control unit that controls the mask support stage based on a detection signal from the detector to align the photomasks on both sides. .   The exposure apparatus according to claim 1, wherein the optical member includes a half mirror that separates light from the projector into reflected light and transmitted light.

Images