Substrate processing device and substrate processing method
Patent Information
- Application Number
- PCT/JP2025/039991
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-26
- Filing Date
- 2025-11-14
- Publication Date
- 2026-09-03
Smart Images
Figure JP2025039991_03092026_PF_FP_ABST
Abstract
Description
Substrate processing apparatus and substrate processing method
[0001] The subject matter disclosed herein relates to substrate processing apparatus and substrate processing methods.
[0002] Conventionally, exposure apparatuses are known for directly exposing patterns onto the upper surface of substrates, such as semiconductor substrates and printed circuit boards, in order to manufacture such substrates. In this type of exposure apparatus, alignment marks formed on the substrate are detected, and the exposure on the substrate is aligned based on the position of the alignment marks. For example, Patent Document 1 describes detecting alignment marks by performing a template matching process between a template image stored in a memory unit and a real image acquired by a CCD camera.
[0003] Japanese Patent Publication No. 2006-214816
[0004] Increasing the number of alignment marks can contribute to improving alignment accuracy. Similarly, increasing the camera resolution can also contribute to improving alignment accuracy. However, in both cases, there was a technical challenge: the increase in image data led to an increase in the amount of data transferred to the image processing unit.
[0005] The objective of the present invention is to provide a technology that can efficiently transfer image data while maintaining the accuracy of alignment mark detection.
[0006] To solve the above problems, the first embodiment is a substrate processing apparatus comprising: a stage for holding a substrate having alignment marks; an imaging unit for capturing images of the alignment marks on the substrate held on the stage and acquiring multi-tone image data; a compression unit for compressing the image data acquired by the imaging unit according to predetermined conditions; and an image processing unit for detecting the position of the alignment marks based on the image data compressed by the compression unit, wherein the compression unit compresses the image data that the image processing unit does not use for detecting the position of the alignment marks.
[0007] The second embodiment is a substrate processing apparatus according to the first embodiment, wherein the compression unit determines whether the grayscale value shown by the image data is within a predetermined threshold range, and compresses the image data that is outside the threshold range.
[0008] A third embodiment is a substrate processing apparatus according to the second embodiment, wherein the compression unit compresses the image data outside the threshold range into 1 bit information by converting the grayscale value indicated by the image data to a first value if it is less than the lower limit of the threshold range, and to a second value if it exceeds the upper limit of the threshold range.
[0009] A fourth embodiment is a substrate processing apparatus according to the third embodiment, wherein the compression unit converts the image data in a first distribution region in the grayscale value distribution shown by a series of image data, in which the grayscale value exceeds the lower limit but falls below the lower limit without exceeding the upper limit, into the first value.
[0010] The fifth embodiment is a substrate processing apparatus according to the third or fourth embodiment, wherein the compression unit converts the image data in a second distribution region in which the grayscale value distribution shown by a series of image data exceeds the upper limit without falling below the lower limit, after the grayscale value has fallen below the upper limit, into the second value.
[0011] The sixth embodiment is a substrate processing apparatus according to any of the first to fifth embodiments, wherein the image processing unit detects the position of the alignment mark by shape matching.
[0012] The seventh embodiment is a substrate processing apparatus according to any of the first to sixth embodiments, further comprising an exposure head for emitting light onto the substrate.
[0013] The eighth aspect is a substrate processing method comprising: an image data acquisition step of acquiring multi-tone image data by imaging alignment marks formed on the substrate held on a stage; a compression step of compressing the image data acquired in the image data acquisition step according to predetermined conditions; and a position detection step of detecting the position of the alignment marks based on the image data compressed in the compression step, wherein the compression step includes a step of compressing image data from the image data of the alignment marks that is not used for position detection of the alignment marks in the position detection step.
[0014] According to the first to eighth embodiments, image data transfer can be improved by compressing image data of areas not used for alignment mark detection.
[0015] According to the substrate processing apparatus of the second embodiment, the transfer of image data can be improved by compressing image data outside the threshold range.
[0016] According to the substrate processing apparatus of the third embodiment, image data outside the threshold range can be significantly compressed, thereby further improving the transfer efficiency of image data.
[0017] According to the fourth embodiment and the substrate processing apparatus of the fourth embodiment, image data of unnecessary distribution areas that do not contribute to the detection of alignment marks can be compressed, thereby further improving data transfer efficiency.
[0018] According to the substrate processing apparatus of the sixth embodiment, alignment marks can be identified with high precision by shape matching.
[0019] This is a perspective view showing the overall configuration of the exposure apparatus according to the embodiment. This is a block diagram relating to the processing of image data. This is a diagram showing alignment marks. This is a control block diagram of the exposure apparatus. This is a diagram showing the first grayscale value distribution. This is a diagram showing another example of setting the threshold range. This is a diagram showing the second grayscale value distribution. This is a diagram showing the third grayscale value distribution. This is a diagram showing the timing chart relating to the transmission of image data.
[0020] Embodiments of the present invention will be described below with reference to the attached drawings. Note that the components described in these embodiments are merely illustrative and are not intended to limit the scope of the present invention to them alone. In the drawings, for ease of understanding, the dimensions and number of parts may be exaggerated or simplified as needed.
[0021] Figure 1 and subsequent figures define an XYZ Cartesian coordinate system to explain the positional relationships of the elements. Here, the X and Y axes are defined as horizontal directions, and the Z axis is defined as vertical. In the following explanation, the +Z direction is defined as vertically upward, and the -Z direction is defined as vertically downward.
[0022] <1. Embodiment> Figure 1 is a perspective view showing the overall configuration of an exposure apparatus 1 according to an embodiment. The exposure apparatus 1 is a substrate processing apparatus that irradiates light onto the upper surface of a substrate W coated with a photosensitive material to draw a pattern on the upper surface of the substrate W without a mask. The substrate W is, for example, a printed circuit board or a semiconductor substrate. For example, in the manufacturing process of a printed circuit board, the process of forming a layer on the upper surface of the substrate W in another apparatus and the process of exposing a pattern on the upper surface of the substrate W in this exposure apparatus 1 are repeatedly performed. This produces a multilayer printed circuit board.
[0023] The exposure apparatus 1 comprises a base 10, a gantry 15, a first stage 21, a first moving mechanism 23, a second stage 25, a second moving mechanism 27, an exposure unit 40, an imaging unit 50, a compression unit 60 (see Figure 2), and a control unit 70.
[0024] The base 10 is a support base that supports each element of the exposure apparatus 1, such as the gantry 15 and the first stage 21. The base 10 has a flat, plate-like shape that extends along the horizontal plane. The base 10 is made of a stone material such as granite. The base 10 is fixed to the factory floor. The base 10 is rectangular in shape when viewed from above. The long side of the base 10 is parallel to the Y-axis direction. The short side of the base 10 is parallel to the X-axis direction.
[0025] The gantry 15 is fixed to the upper surface of the base 10. The gantry 15 has a pair of legs 151 and a bridging portion 152. The pair of legs 151 are spaced apart in the X-axis direction. Each leg 151 extends upward (in the +Z direction) from the upper surface of the base 10. The bridging portion 152 connects the upper ends of the legs 151 in the X-axis direction. A through-hole 18 is formed between the upper surface of the base 10 and the gantry 15, through which the substrate W can pass in the Y-axis direction.
[0026] The first stage 21 is movable along the Y-axis. The first stage 21 has a flat, plate-like shape. In a top view, the shape of the first stage 21 is rectangular, smaller than the base 10. The first stage 21 is positioned above the base 10 in a substantially horizontal position.
[0027] The first moving mechanism 23 is a mechanism for moving the first stage 21 in the Y-axis direction relative to the base 10 and the gantry 15. The first moving mechanism 23 is a linear motor mechanism having a pair of guide rails and a linear motor. The pair of guide rails are rails for guiding the first stage 21 in the Y-axis direction. The pair of guide rails are provided on the upper surface of the base 10 at intervals in the X-axis direction and extend linearly along the Y-axis direction. The linear motor has a stator provided on the upper surface of the base 10 and a mover fixed to the lower surface of the first stage 21. When a drive signal is supplied to the linear motor from the control unit 70, the mover moves along the stator in the Y-axis direction due to the magnetic attractive and repulsive forces generated between the stator and the mover. As a result, the first stage 21 moves in the Y-axis direction relative to the base 10. Note that the drive source of the first moving mechanism 23 is not limited to a linear motor. The first moving mechanism 23 may be, for example, a mechanism that converts the rotational motion of a servo motor into linear motion using a ball screw.
[0028] The second stage 25 is movable along the X-axis. The second stage 25 has a flat, plate-like shape. In a top view, the shape of the second stage 25 is a rectangle smaller than that of the first stage 21. The second stage 25 is positioned above the first stage 21 in a substantially horizontal position.
[0029] The second moving mechanism 27 is a mechanism for moving the second stage 25 in the X-axis direction relative to the first stage 21. The second moving mechanism 27 is a linear motor mechanism having a pair of guide rails and a linear motor. The pair of guide rails are arranged on the upper surface of the first stage 21 at intervals in the Y-axis direction. Each guide rail extends linearly along the X-axis direction. The pair of guide rails are rails for guiding the second stage 25 in the X-axis direction. However, the second moving mechanism 27 is not limited to a linear motor mechanism, and may be, for example, a ball screw mechanism.
[0030] The substrate W is supported on the upper surface of the second stage 25 in a substantially horizontal position. The second stage 25 may have chuck pins for fixing the substrate W and a plurality of suction holes for adsorbing the substrate W. The exposure apparatus 1 moves the substrate W in the Y-axis direction (main scanning direction) and the X-axis direction (sub-scanning direction), respectively, by operating the first moving mechanism 23 and the second moving mechanism 27.
[0031] The exposure unit 40 is a unit that exposes the substrate W supported by the second stage 25. The exposure unit 40 has four exposure heads 41. The multiple exposure heads 41 are fixed to the bridging portion 152 of the gantry 15. The multiple exposure heads 41 are arranged at equal intervals along the X-axis. Each exposure head 41 has a spatial light modulation element to form a desired pattern on the substrate W. As the spatial light modulation element, for example, a GLV (Grating Light Valve) (registered trademark) or a DMD (Digital Micromirror Device) can be used. A GLV is a diffraction grating type spatial light modulator that uses a minute diffraction grating structure to control the diffraction of laser light, thereby adjusting the transmittance and reflectance of the light and forming a patterned light. A DMD uses a minute mirror array to change the direction of light reflection by tilting individual mirrors and forming a patterned light.
[0032] The exposure unit 40 spatially modulates the laser light supplied from the light source 43 to form patterned light, which is then irradiated onto the substrate W. The light source 43 can be, for example, a laser oscillator, an LED (Light Emitting Diode), or a mercury lamp. The laser light from the light source 43 is converted into linear laser light by the illumination optical system 45 and guided to the spatial light modulator of the exposure head 41. The illumination optical system 45 includes, for example, a collimator lens that converts the light from the light source 43 into parallel light, and a cylindrical lens that converts it into linear light.
[0033] The exposure apparatus 1 alternately performs a main scanning process and a sub-scanning process. In the main scanning process, the exposure apparatus 1 moves the substrate W in the Y-axis direction while multiple exposure heads 41 emit pattern light. In the main scanning process, the exposure apparatus 1 moves the substrate W relative to the multiple exposure heads 41 in the Y-axis direction. This draws a pattern in a striped area. In the sub-scanning process, the substrate W is moved a predetermined distance in the X-axis direction to position the substrate W at the starting position of the next exposure. The exposure apparatus 1 exposes the entire surface of the substrate W by repeating these main scanning and sub-scanning processes.
[0034] The imaging unit 50 images the alignment marks M formed on the substrate W supported by the second stage 25 and acquires image data including the alignment marks M. The imaging unit 50 is attached to the bridging portion 152 of the gantry 15. The imaging unit 50 performs imaging based on a drive signal from the control unit 70.
[0035] Figure 2 is a block diagram relating to the processing of image data. The imaging unit 50 includes an image sensor 51 and an AD converter 53. The image sensor 51 is a semiconductor device having a plurality of photoreceiving elements that convert light into electrical signals, and is specifically an image sensor such as a CCD (Charge-Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor). The image sensor 51 is a line sensor in which a plurality of photoreceiving elements are arranged in the X-axis direction.
[0036] The AD converter 53 converts the electrical signal output by the image sensor 51 into image data that is multi-gradation digital data. In this embodiment, in order to acquire an image including the alignment mark M as a grayscale image, the AD converter 53 converts the electrical signal from the image sensor 51 into 256-gradation 8-bit data in which black is 00h and white is ffh. The imaging unit 50 outputs the acquired image data to the compression unit 60. The step in which the imaging unit 50 images the alignment mark M on the substrate W held on the second stage 25 and acquires multi-gradation image data as described above corresponds to an "image data acquisition step".
[0037] The compression unit 60 compresses the image data input from the imaging unit 50 according to predetermined conditions (compression step). Then, the compression unit 60 transmits the compressed image data to the control unit 70 (image processing apparatus). The conditions under which the compression unit 60 performs compression will be described later.
[0038] FIG. 3 is a diagram showing the alignment mark M. The alignment mark M shown in FIG. 3 has a cross shape, but may have other shapes. The alignment mark M is formed by, for example, etching or laser processing. When imaging the alignment mark M, the control unit 70 moves the substrate W in the X-axis direction such that the alignment mark M falls within the imaging area of the imaging unit 50. Thereafter, the control unit 70 moves the substrate W in the Y-axis direction, and images the alignment mark M when the alignment mark M passes directly below the imaging unit 50 (see FIG. 3). When a plurality of alignment marks M are formed at different positions in the X-axis direction, the control unit 70 sequentially moves the substrate W to the position of each alignment mark M. The control unit 70 repeats the operation of moving the substrate W in the X-axis direction and then moving it in the Y-axis direction, and causes the imaging unit 50 to image all alignment marks M.
[0039] It should be noted that the imaging unit 50 may include a light source for illuminating an object. Further, the exposure apparatus 1 may include a moving mechanism that moves the imaging unit 50 in the X-axis direction. As such a moving mechanism, for example, a linear motor mechanism or a ball screw mechanism can be used. The exposure apparatus 1 may include a plurality of imaging units 50 arranged in the X-axis direction. The imaging unit 50 may include a two-dimensional image sensor instead of a line sensor.
[0040] FIG. 4 is a control block diagram of the exposure apparatus 1. The control unit 70 is a unit for controlling the operation of each part of the exposure apparatus 1. As shown in FIG. 4, the control unit 70 is a computer including a processor 71 such as a CPU (Central Processing Unit) and a memory 72 such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The memory 72 may include an auxiliary storage device such as a hard disk drive.
[0041] The control unit 70 is electrically and communicably connected to the first moving mechanism 23, the second moving mechanism 27, the exposure unit 40, the imaging unit 50, and the compression unit 60.
[0042] The memory 72 stores a detection program P1 and an exposure program P2. The detection program P1 and the exposure program P2 may be recorded on a computer-readable recording medium that can be read by the control unit 70 which is a computer. The processor 71 executes position detection of the alignment mark M by executing the detection program P1 (position detection step). Further, the processor 71 executes exposure processing by executing the exposure program P2.
[0043] In this embodiment, the control unit 70 applies shape matching to detect the position of the alignment mark M. Specifically, it detects edge portions in the image data transmitted from the compression unit 60 where the gradation value (luminance value) changes abruptly, and extracts these gradation value change portions as edge information. Based on the obtained edge information, the control unit 70 compares a template Tm1 (see Figure 3) representing the outline of the alignment mark M, which has been prepared in advance, with the features in the image to identify the most similar region. The control unit 70 then acquires the position of the identified region (for example, the centroid coordinates of the region) as the position of the alignment mark M.
[0044] As shown in Figure 3, when the alignment mark M is imaged, a gradation value distribution H is obtained from the series of image data. In this gradation value distribution H, the alignment mark M has high gradation values (high brightness), while the other parts have low gradation values (low brightness). Here, as shown in Figure 3, if there is a foreign object 9 such as a stain within the alignment mark M, a decrease in gradation value occurs at the corresponding location. However, in shape matching, the shape of the alignment mark M is detected by the change in gradation value using the template Tm1, so the position of the alignment mark M can be detected without being affected by the foreign object 9.
[0045] The compression unit 60 compresses the image data of the alignment mark M acquired by the imaging unit 50 that the control unit 70 (image processing unit) does not use for position detection of the alignment mark M. For example, in position detection by shape matching, information other than changes in the grayscale value of the edge portion is basically unnecessary. Therefore, the compression unit 60 compresses the image data that does not correspond to the edge portion. Specifically, the compression unit 60 determines whether the grayscale value of the image data is within a predetermined threshold range, and if the grayscale value is outside the threshold range, it compresses the image data. More specifically, if the grayscale value of the image data is outside the threshold range, the compression unit 60 compresses the image data from 8 bits to 1 bit of information.
[0046] Figure 5A shows the first grayscale value distribution H1. As shown in Figure 5A, the compression unit 60 sets the grayscale value of the image data to the lower limit of the threshold range L ｍｉｎIf it is less than the threshold, the image data is converted into 0b (first value) which is 1-bit information. On the other hand, when the gradation value of the image data is the upper limit L of the threshold range ｍａｘ is exceeded, the image data is converted into 1b (second value) which is 1-bit information.
[0047] As described above, by setting the image data used for position detection of the alignment mark M as uncompressed and compressing only the image data not used for position detection of the alignment mark M, the transfer efficiency of the image data can be improved without reducing the position detection accuracy of the alignment mark M.
[0048] In particular, in the case of shape matching, by setting image data within a preset threshold range as uncompressed, information about edge portions necessary for detecting the alignment mark M can be retained. On the other hand, by compressing image data outside the threshold range, the data amount of regions other than the edge portions can be reduced. Therefore, the transfer efficiency of image data can be improved without reducing the position detection accuracy of the alignment mark M by shape matching.
[0049] Furthermore, compressing image data into 1-bit information can significantly reduce the amount of image data, thereby greatly improving the transfer efficiency of image data.
[0050] FIG. 5B is a diagram showing another example of setting a threshold range. The lower limit L of the threshold range ｍｉｎ and the upper limit L ｍａｘ It is not essential that both of them are preset. In FIG. 5B, only the lower limit L ｍｉｎ is set, and the upper limit L of the threshold range ｍａｘ is the maximum gradation value (ffh). In this case, the compression unit 60 compresses only image data that does not exceed the lower limit L ｍｉｎ into 0b. Although not shown in the drawings, when only the upper limit L ｍａｘ is set, the lower limit of the threshold range is set to the minimum gradation value (00h). In this case, the compression unit 60 may be configured to compress only image data exceeding the upper limit L ｍａｘ into 1b.
[0051] The compression unit 60 may perform image data compression by analyzing the shape of the grayscale value distribution. Figure 6A shows a second grayscale value distribution H2. In this grayscale value distribution H2, the grayscale value is the lower limit L ｍｉｎ After exceeding the upper limit L ｍａｘ Without exceeding the lower limit L ｍｉｎ It includes a distribution region A1 that is below a certain threshold. The grayscale values of the image data in distribution region A1 are within the threshold range. However, the compression unit 60 may compress the image data in this distribution region A1 to 0b (the first value). Distribution region A1 corresponds to the "first distribution region".
[0052] Figure 6B shows the third grayscale value distribution H3. In this grayscale value distribution H3, the grayscale value is the upper limit L ｍａｘ After falling below the lower limit L ｍｉｎ Without falling below the upper limit L ｍａｘ It includes a distribution region A2 that exceeds [a certain value]. The grayscale values of the image data in distribution region A2 are within the threshold range. However, the compression unit 60 may compress the image data within this distribution region A2 to 1b (the second value). Distribution region A2 corresponds to the "second distribution region".
[0053] Distribution regions A1 and A2 represent errors within the alignment mark M caused by foreign objects 9 shown in Figure 3, or by factors such as lighting brightness, and are unnecessary for position detection of the alignment mark M. Therefore, by compressing the image data of distribution regions A1 and A2, which include such errors, data transfer efficiency can be further improved without reducing the accuracy of position detection of the alignment mark M.
[0054] Figure 7 is a timing chart for transmitting image data. As shown in Figure 7, the compression unit 60 transmits the image data D, along with a clock signal CK, a data recognition signal S, and an enable signal E, to the control unit 70. The image data D is transmitted using a serial communication method. That is, the image data D is transmitted bit by bit in chronological order using a single communication line. Uncompressed image data D is transmitted in 8 bits, and compressed image data D is transmitted in 1 bit.
[0055] The clock signal CK, the data recognition signal S, and the enable signal E are transmitted to the image data D using a parallel communication method. The clock signal CK functions as a synchronization signal for the image data. In one cycle of the clock signal CK, one bit of the image data D is transmitted to the control unit 70. The data recognition signal S is a signal for identifying one pixel of the image data D. The data recognition signal S transitions between a High level and a Low level at the timing of the switching of the image data D. The enable signal E is a signal indicating that valid data is being transmitted. When the image data D is compressed, the period of the data recognition signal S becomes shorter than when it is uncompressed. Therefore, the control unit 70 can determine whether the image data D is compressed or uncompressed based on the period of the data recognition signal S. <2. Modifications> Although embodiments have been described above, the present invention is not limited to those described above, and various modifications are possible.
[0056] In the above embodiment, shape matching is applied to detect the position of the alignment mark M, but other methods may also be applied. For example, the centroid position of the alignment mark M may be determined by finding the centroid of the edges on both sides from the slope of the gradation value change corresponding to the edges on both sides of the alignment mark M.
[0057] Although this invention has been described in detail, the above description is illustrative in all respects, and the invention is not limited thereto. It is understood that countless variations not illustrated can be conceived without falling outside the scope of this invention. The components described in each of the above embodiments and variations can be combined or omitted as appropriate, as long as they do not contradict each other.
[0058] 1: Exposure apparatus (substrate processing apparatus) 40: Exposure unit 50: Imaging unit 60: Compression unit 70: Control unit (image processing unit) M: Alignment mark W: Substrate
Claims
1. A substrate processing apparatus comprising: a stage for holding a substrate having alignment marks; an imaging unit for imaging the alignment marks on the substrate held on the stage and acquiring multi-tone image data; a compression unit for compressing the image data acquired by the imaging unit according to predetermined conditions; and an image processing unit for detecting the position of the alignment marks based on the image data compressed by the compression unit, wherein the compression unit compresses image data from the image data that the image processing unit does not use for detecting the position of the alignment marks.
2. A substrate processing apparatus according to claim 1, wherein the compression unit determines whether the grayscale values shown by the image data are within a predetermined threshold range, and compresses the image data that is outside the threshold range.
3. A substrate processing apparatus according to claim 2, wherein the compression unit compresses the image data outside the threshold range into 1-bit information by converting the gradation value indicated by the image data to a first value if it is less than the lower limit of the threshold range, and to a second value if it exceeds the upper limit of the threshold range.
4. A substrate processing apparatus according to claim 3, wherein the compression unit converts the image data in a first distribution region in which the grayscale value distribution shown by a series of image data exceeds the lower limit value but does not exceed the upper limit value and falls below the lower limit value into the first value.
5. A substrate processing apparatus according to claim 3 or claim 4, wherein the compression unit converts the image data in a second distribution region in which the grayscale value distribution shown by a series of image data exceeds the upper limit without falling below the lower limit, after the grayscale value has fallen below the upper limit, into the second value.
6. A substrate processing apparatus according to any one of claims 1 to 5, wherein the image processing unit detects the position of the alignment mark by shape matching.
7. A substrate processing apparatus according to any one of claims 1 to 6, further comprising: an exposure head for emitting light onto the substrate.
8. A substrate processing method comprising: an image data acquisition step of acquiring multi-tone image data by imaging alignment marks formed on the substrate held on a stage; a compression step of compressing the image data acquired in the image data acquisition step according to predetermined conditions; and a position detection step of detecting the position of the alignment marks based on the image data compressed in the compression step, wherein the compression step includes a step of compressing image data of the alignment marks that is not used for position detection of the alignment marks in the position detection step.