Alignment device, method and equipment for double-sided exposure

Abstract

The disclosure provides an alignment device, method and equipment for double-sided exposure, and belongs to the technical field of printed circuit boards. The device comprises positioning signs (11), marking signs (12) and a position acquisition device (13). Before each sample to be exposed is exposed, the position information of the positioning signs (11) is acquired by the position acquisition device (13), so as to obtain the position variation of the positioning signs (11) in actual production. Because the relative positions of the marking signs (12) and the positioning signs (11) are unchanged, the position variation of the marking signs (12) in actual production can be obtained. According to the position variation, the position of an exposure pattern on the other side of the sample to be exposed is adjusted in real time, thereby solving the problem of inaccurate exposure alignment caused by the fact that the marking signs (12) cannot be positioned in real time in the prior art, and improving the accuracy of double-sided alignment of the sample to be exposed. The most illustrative figure: Fig. 1

Description

A double-sided exposure alignment device, method and equipment Technical Field

[0001] This invention relates to an alignment device, method, and apparatus for double-sided exposure, belonging to the field of printed circuit board technology. Background Technology

[0002] When producing inner layer circuit boards, laser direct imaging (LDI) exposure machines require precise alignment of the images on both sides of the printed circuit board (PCB) to ensure accurate positioning of the patterns on both sides of the PCB.

[0003] During the production process, laser marking is typically used to independently mark two marks for precise alignment of the inner PCB board. A mark exposure aperture is located at the bottom of the vacuum chuck. During the first exposure printing of the inner PCB board, two marks are laser-marked on the non-exposed area of ​​the other edge of the PCB board using the mark exposure aperture. After flipping the board, the rotation and translation of the PCB are calculated using the coordinates of the two laser-marked marks on the PCB board surface and the coordinates of the aperture that produced these marks, thus achieving precise alignment of the two sides of the PCB. Therefore, to achieve precise alignment of the inner PCB board, the position of the mark exposure aperture needs to be accurately located.

[0004] However, the mark exposure aperture is fixed on a metal vacuum chuck with a side length of ≥500mm. As production progresses, if the internal temperature of the machine changes significantly, the metal vacuum chuck will expand and contract due to the temperature. Moreover, the vacuum chuck has a vacuum cavity in the middle. When the PCB board is vacuumed, the vacuum level inside the cavity reaches -20kPa. Under the pressure of 20kPa, the main body of the vacuum chuck will deform, and this deformation is irregular and non-linear. Since thermal expansion and contraction and vacuum adsorption both cause the vacuum chuck to deform, the position of the mark exposure aperture installed on the edge of the chuck will also change. Because the mark exposure aperture is covered by the PCB to be exposed during exposure, it cannot be calibrated simultaneously or in real time. Therefore, the existing positioning method of the mark exposure aperture is to calibrate and position the mark exposure aperture at regular intervals. If the vacuum chuck expands, contracts or deforms during the calibration interval, the position of the mark exposure aperture will change. Therefore, the traditional positioning method cannot accurately position the mark exposure aperture simultaneously or in real time during continuous exposure of the PCB board.

[0005] Summary of the Invention

[0006] To address the problem of misalignment caused by changes in the position of the mark exposure aperture due to expansion, contraction, or deformation of the vacuum chuck during the calibration interval, this invention provides a double-sided exposure alignment device, method, and exposure equipment including the double-sided exposure alignment device.

[0007] The first object of the present invention is to provide an alignment apparatus for double-sided exposure, the apparatus comprising:

[0008] Positioning markers, marking markers, and location acquisition devices;

[0009] The positioning mark is used to determine the position of the marking mark in real time, thereby determining the position of the exposure pattern of the sample to be exposed based on the position of the marking mark;

[0010] The marking marks are used to mark the samples to be exposed;

[0011] The location acquisition device is used to acquire the location information of the positioning marker in real time.

[0012] Optionally, the relative positional change of the positioning mark and the marking mark is less than a predetermined value, which is set according to the alignment accuracy required when the sample to be exposed is subjected to double-sided exposure.

[0013] Optionally, the distance between the positioning mark and the marking mark is less than 20 mm and / or they are connected by an anti-deformation material.

[0014] Optionally, the device further includes:

[0015] A sample carrier and a marking device; the sample carrier is used to carry the sample to be exposed; the marking device is used to mark the sample to be exposed using the marking mark;

[0016] The marking mark is located on the sample carrier.

[0017] Optionally, the marking mark is located on the edge portion of the sample carrier.

[0018] Optionally, the marking mark corresponds one-to-one with the positioning mark; the positioning mark is used to determine the position of the corresponding marking mark.

[0019] A second objective of this invention is to provide an alignment method for double-sided exposure, the method being applied in the aforementioned double-sided exposure alignment apparatus, the method comprising:

[0020] Expose one side of the sample to be exposed;

[0021] The other side of the sample to be exposed is marked by marking.

[0022] Real-time acquisition of location information of positioning markers;

[0023] The location information of the marking mark is determined based on the location information of the positioning mark obtained in real time;

[0024] The other side of the sample is aligned and exposed based on the position information of the marking marks.

[0025] Optionally, before exposing one side of the sample to be exposed, the method further includes:

[0026] The system acquires the position information of the positioning mark when exposing one side of the sample to be exposed in real time, and exposes an intermediate mark on one side of the sample to be exposed based on the acquired position information of the positioning mark. The intermediate mark is used to determine the position of the exposed pattern on its side.

[0027] Optionally, before marking the other side of the sample to be exposed by marking, the method further includes:

[0028] Select at least two marking marks according to the size of the sample to be exposed;

[0029] The sample to be exposed is placed over the marking mark, but the positioning mark corresponding to the selected marking mark is not covered.

[0030] Optionally, aligning and exposing the other side of the sample according to the position information of the marking marks includes:

[0031] The position of the exposure pattern on the other side of the sample to be exposed is determined in real time based on the position information of the marking marks;

[0032] The other side of the sample to be exposed is exposed based on the position of the exposure pattern on the other side determined in real time.

[0033] A third object of the present invention is an exposure apparatus comprising the above-described alignment device for double-sided exposure.

[0034] The beneficial effects of this invention are:

[0035] By providing a double-sided exposure alignment device, including positioning marks, marking marks, and a position acquisition device, a suitable marking mark is selected according to the size of each sample to be exposed before exposure. The position acquisition device acquires the position information of the positioning mark corresponding to the selected marking mark, thereby obtaining the position information of the marking mark and determining the amount of change of the position of the marking mark relative to the predetermined position when the sample is exposed. The position of the other side of the sample to be exposed is adjusted in real time according to the amount of change. This solves the problem of inaccurate exposure alignment caused by the inability of the marking mark to be positioned in real time in the prior art, and improves the accuracy of double-sided alignment of the sample to be exposed. By ensuring that the distance between the positioning mark and the marking mark is less than 20mm and / or by connecting them with an anti-deformation material, the relative positional change of the two during exposure is guaranteed to be less than the predetermined value set according to the alignment accuracy required for the exposure of the sample, thereby improving the accuracy of the double-sided alignment of the sample to be exposed. Before each sample to be exposed, the position information of the positioning mark is obtained through a position acquisition device, and then the position information of the marking mark is obtained, thereby determining the amount of change of the position of the marking mark relative to the predetermined position during the exposure of the sample. Based on this amount of change, the position of the predetermined exposure pattern on the other side of the sample to be exposed is adjusted in real time, thereby improving the accuracy of the double-sided alignment of the sample to be exposed. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 is a schematic diagram of the alignment device for double-sided exposure provided in Embodiment 1 of the present invention;

[0038] Figure 2 is a schematic diagram of the alignment device for double-sided exposure provided in embodiments two and three of the present invention;

[0039] Figure 3 is a schematic diagram showing the position of the positioning mark and the marking mark located at the lower edge of the loading suction cup in an embodiment of the present invention;

[0040] Figure 4 is a schematic diagram showing the positions of the positioning mark and the marking mark on one side and the lower part of the edge of the loading suction cup in an embodiment of the present invention.

[0041] Figure 5 is a schematic diagram of the position of the sample to be exposed on the chuck for exposure.

[0042] Figure 6 is a schematic diagram of an exposure device including a double-sided exposure alignment device provided in Embodiment 4 of the present invention;

[0043] Figure 7 is a front view of the positioning mark and the marking mark in this invention, where 1 is the marking mark and 3 is the positioning mark;

[0044] Figure 8 is a cross-sectional view of the positional relationship between the 405 laser source, the marking mark, and the positioning mark in this invention, wherein 1 is the marking mark, 3 is the positioning mark, 4 is the lens, 5 is the 405 laser, and 6 is the laser controller.

[0045] Figure 9 is a schematic diagram of the connection between the positioning mark and the marking mark through the anti-deformation material in an embodiment of the present invention, wherein 1 is the marking mark, 2 is the anti-deformation material, and 3 is the positioning mark;

[0046] Figure 10 is a schematic diagram of the placement of the sample to be exposed in the double-sided exposure method provided in Embodiment 5 of the present invention;

[0047] Figure 11 is a schematic diagram of the exposure process of the sample to be exposed in the double-sided exposure method provided in Embodiment 5 of the present invention. Detailed Implementation

[0048] In industrial production, the alignment accuracy of the front and back sides of the PCB inner layer without holes is required to be within 10μm. However, factors affecting this alignment accuracy include the repeatability of the system axis, the accuracy of the chuck system, and the image processing accuracy. Among them, the chuck system is affected by the following two reasons: (1) the chuck body is made of aluminum alloy, which has the characteristic of thermal expansion and contraction with temperature changes; (2) the chuck needs to vacuum adsorb the PCB board, and vacuum adsorption will cause the chuck to deform. Therefore, the chuck system has a great impact on the alignment accuracy of the front and back sides of the PCB inner layer without holes. In actual application, the thermal expansion coefficient of aluminum alloy is 23μm / ℃.m, the temperature fluctuation is ±2℃, and the size of the chuck is 650mm (width) * 850mm (length). Its edge deformation is as follows:

[0049] 23 * 4 * 0.85 = 78.2 μm (length); 23 * 4 * 0.65 = 59.8 μm (width);

[0050] This means that when the temperature fluctuates by ±2℃, the width of the suction cup changes by 59.8μm and the length by 78.2μm. The alignment accuracy between the front and back sides changes significantly with temperature fluctuations, far exceeding the 10μm specification.

[0051] When vacuum adsorbing the PCB board, the main body of the chuck is an aluminum alloy part measuring 650mm (width) * 850mm (length) * 23mm (thickness), with a vacuum chamber in the middle. When the vacuum is drawn, the vacuum degree inside the chamber reaches -20kPa. Under the pressure of 20kPa, the chuck body undergoes irregular nonlinear deformation. Through actual testing, the deformation is about 5μm. Although it does not exceed the 10μm limit, it has already contributed 50% to the alignment accuracy of the system, and the impact is relatively large.

[0052] For the reasons mentioned above (1), it is suggested to use materials with low coefficients of thermal expansion, such as Invar steel, marble, silicon carbide, etc. However, these materials are difficult to process, marble and silicon carbide are easily broken, and their cost is 5-10 times that of aluminum alloys. Therefore, these materials cannot be considered.

[0053] The above reason (2) is that the deformation of the suction cup body is irregular and nonlinear, so it is impossible to find its change law and solve it.

[0054] Since the PCB board is covered on the mark hole during the production process, the commonly used method is to compensate for the deformation of the suction cup body caused by temperature changes and vacuum adsorption by periodically calibrating the positioning. This method cannot determine the amount of deformation of the suction cup body in real time.

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0056] Example 1

[0057] This embodiment provides an alignment device for double-sided exposure, as shown in Figure 1. The device includes:

[0058] Positioning mark 11, marking mark 12, and position acquisition device 13;

[0059] The positioning mark 11 is used to determine the position of the marking mark 12 in real time, thereby determining the position of the exposure pattern of the sample to be exposed based on the position of the marking mark 12;

[0060] Marking mark 12 is used for marking the sample to be exposed;

[0061] The location acquisition device 13 is used to acquire the location information of the positioning marker in real time.

[0062] This invention provides a double-sided exposure alignment device, including a positioning mark, a marking mark, and a position acquisition device. The position acquisition device acquires the position information of the positioning mark in real time, thereby obtaining the real-time position information of the marking mark. Then, based on the real-time position information of the marking mark, the other side of the sample to be exposed is aligned and exposed. This solves the problem of inaccurate exposure alignment caused by the inability of the marking mark to be accurately positioned in real time in the prior art, and achieves the effect of improving the accuracy of double-sided alignment of the sample to be exposed.

[0063] Example 2

[0064] This embodiment provides an alignment device and method for double-sided exposure. Referring to Figure 2, the device includes:

[0065] Positioning mark 11, marking mark 12, position acquisition device 13, sample carrying device 14, and marking device 15;

[0066] The positioning mark 11 is used to determine the position of the marking mark 12 in real time, thereby determining the position of the exposure pattern of the sample to be exposed based on the position of the marking mark 12;

[0067] Marking mark 12 is used for marking the sample to be exposed;

[0068] Location acquisition device 13 is used to acquire the location information of the positioning marker in real time;

[0069] The relative positional change of the positioning mark 11 and the marking mark 12 is less than a predetermined value, which is set according to the alignment accuracy required when the sample to be exposed is double-sided exposed; the distance between the positioning mark 11 and the marking mark 12 is less than 20mm and / or they are connected by an anti-deformation material.

[0070] The sample carrier 14 is used to carry the sample to be exposed; the marking device 15 is used to mark the sample to be exposed by the marking mark 12;

[0071] Marking mark 12 is located on sample carrier device 14.

[0072] This embodiment uses a PCB board as the sample to be exposed, a PCB board as the sample carrier device, a PCB board carrier suction cup made of aluminum alloy, a marking mark 12 as a marking hole on the PCB board, a CCD camera as the position acquisition device 13, and a 405 laser source as the marking device 15 for illustration.

[0073] Specifically, when the PCB board is placed on the suction cup, it covers the marking hole so that the 405 laser source can mark the side of the PCB board facing that direction, ensuring that the PCB board is not covered by the positioning mark so that the CCD camera can obtain the position information of the positioning mark. The positioning mark can be a positioning hole on the suction cup, the distance between the positioning hole and the marking hole is less than 20mm, or it can be a marker connected to the marking hole by an anti-deformation material, as shown in Figure 9. As long as the relative position change between the positioning mark and the marking hole during the operation is less than a predetermined value, the predetermined value is set according to the alignment accuracy required when the PCB board is exposed on both sides.

[0074] For example, if the alignment accuracy of the front and back sides of the PCB board is required to be within 10μm, then the predetermined value is set to 2μm. If the positioning mark is a positioning hole located on the chuck, then the distance between the positioning hole and the marking hole is set to be less than 20mm. During the PCB board exposure process, based on the thermal expansion coefficient of aluminum alloy, the material of the chuck, which is 23μm / ℃.m, and the temperature fluctuation range during the exposure process, which is ±2℃, the relative positional change of the positioning hole and the marking hole is 23*4*0.02=1.8μm<2μm. Furthermore, since the local rigidity of aluminum alloy is greater than the overall rigidity, the vacuum effect is very small when the distance between the positioning hole and the marking hole is small and can be ignored. Through actual testing, the relative positional change of the positioning hole and the marking hole meets the standard of less than the predetermined value of 2μm.

[0075] Similarly, if the positioning mark is a marker connected to the marking hole through an anti-deformation material, then since the anti-deformation material is minimally affected by temperature, the relative positional change between the positioning mark and the marking hole can be ignored.

[0076] In practical applications, anti-deformation materials can be made of materials with low coefficients of thermal expansion, such as Invar steel, marble, and ceramics. These materials are minimally affected by temperature. For example, the coefficient of thermal expansion of Invar steel is 0.8 μm / ℃ / m, that of marble is 5 μm / ℃ / m, and that of ceramics is 7 μm / ℃ / m. Even if the length of the anti-deformation material connecting the positioning mark and the marking hole is as long as 100 mm, its deformation within a temperature range of ±2℃ is 0.8*4*0.1=0.32 μm and 5 μm, respectively. *4*0.1=2μm, 7*4*0.1=2.8μm. Moreover, in practical applications, the anti-deformation material will not be 100mm long. For example, if the distance between the positioning mark and the marking hole is 20mm, then within a temperature change range of ±2℃, the deformation of the anti-deformation material will be 0.8*4*0.02=0.064μm, 5*4*0.02=0.4μm, and 7*4*0.02=0.56μm, respectively. Therefore, the relative positional change between the positioning mark and the marking hole can be ignored.

[0077] To achieve higher alignment accuracy, the distance between the positioning mark and the marking mark can be set to any value less than 20mm.

[0078] During the exposure process, the CCD camera acquires the position information of the positioning marks. When exposing the other side of the PCB board, the position information of the marking holes is determined based on the position information of the positioning marks acquired by the CCD camera. Then, the position of the exposure pattern on the other side of the PCB board is determined based on the position information of the marking holes, and then the exposure is performed.

[0079] For ease of description, the two sides of the PCB board will be referred to as side A and side B, respectively.

[0080] For example, the initial calibration position of the marking hole recorded in the system is denoted as... The initial calibration position of the positioning mark is denoted as When exposing a PCB board, the real-time position of the positioning marker is recorded as follows: The CCD camera acquires the position change of the positioning marker relative to the initial position recorded in the system as follows:

[0081]

[0082]

[0083] Since the relative positional change between the positioning mark and the marking hole is negligible, it can be concluded that the positional change of the marking hole is also:

[0084]

[0085]

[0086] The theoretical value of the marking hole at the marked position on side B is denoted as...

[0087] When flipping the board up and down, the height of the PCB board is recorded as H, and the X coordinate of the bottom edge of the board is marked as X. bottom ;

[0088] Based on the theoretical value of the marking hole's position on side B, the expected position of the marking hole on side B is:

[0089] The actual location of the marking hole captured on side B after flipping the plate.

[0090] Alignment results

[0091] Exposure graphic A-side position Obtained through Y mirror

[0092] That is, the position of the graphic on side B is

[0093] This invention provides a double-sided exposure alignment device, including a positioning mark, a marking mark, and a position acquisition device. The position acquisition device acquires the position information of the positioning mark in real time, thereby obtaining the real-time position information of the marking mark. Then, based on the real-time position information of the marking mark, the other side of the sample to be exposed is aligned and exposed. This solves the problem of inaccurate exposure alignment caused by the inability of the prior art to accurately position the marking mark in real time. By ensuring that the distance between the positioning mark and the marking mark is less than 20mm and / or by connecting them with an anti-deformation material, it is ensured that the relative position change between the two during exposure is less than a predetermined value set according to the alignment accuracy required for the exposure of the sample, thereby improving the accuracy of double-sided alignment of the sample to be exposed.

[0094] In the actual exposure process, the marking marks and positioning marks can be in a one-to-one correspondence, with the positioning mark used to determine the position of the corresponding marking mark; or they can be in a one-to-many correspondence, for example, one marking mark corresponds to two or more positioning marks, and the position information of the marking mark is determined by combining the two positioning marks; or multiple marking marks can correspond to one positioning mark, and the positioning mark determines the position of the above multiple marking marks.

[0095] The following embodiments three and four of the present invention are described with a one-to-one correspondence between the marking mark and the positioning mark, and the positional relationship between the marking mark and the positioning mark is shown in Figure 7.

[0096] Example 3

[0097] This embodiment provides an alignment device and method for double-sided exposure. Referring to Figure 2, the device includes:

[0098] Positioning mark 11, marking mark 12, position acquisition device 13, sample carrying device 14, and marking device 15;

[0099] The positioning mark 11 is used to determine the position of the marking mark 12 in real time, thereby determining the position of the exposure pattern of the sample to be exposed based on the position of the marking mark 12;

[0100] Marking mark 12 is used for marking the sample to be exposed;

[0101] Location acquisition device 13 is used to acquire the location information of the positioning marker in real time;

[0102] The relative positional change of the positioning mark 11 and the marking mark 12 is less than a predetermined value, which is set according to the alignment accuracy required when the sample to be exposed is double-sided exposed; the distance between the positioning mark 11 and the marking mark 12 is less than 20mm and / or they are connected by an anti-deformation material.

[0103] The sample carrier 14 is used to carry the sample to be exposed; the marking device 15 is used to mark the sample to be exposed by the marking mark 12;

[0104] Marking mark 12 is located on sample carrier device 14.

[0105] This embodiment uses a PCB board as the sample to be exposed, a PCB board as the sample carrier device, a PCB board carrier suction cup made of aluminum alloy, a marking mark 12 as a marking hole on the PCB board, a CCD camera as the position acquisition device 13, and a 405 laser source as the marking device 15 for illustration.

[0106] Figure 8 shows a cross-sectional view of the positional relationship between the laser source of the marking device 405 and the marking and positioning marks.

[0107] Specifically, when the PCB board is placed on the chuck, it covers the marking hole so that the 405 laser source can mark the side of the PCB board facing that direction, ensuring that the PCB board is not covered by the positioning mark so that the CCD camera can obtain the position information of the positioning mark. The positioning mark can be a positioning hole on the chuck, the distance between the positioning hole and the marking hole is less than 20mm, or it can be a mark connected to the marking hole by an anti-deformation material, as long as the relative position change between the positioning mark and the marking hole during the operation is less than a predetermined value. This predetermined value is set according to the alignment accuracy required when the PCB board is exposed on both sides.

[0108] For example, if the alignment accuracy of the front and back sides of the PCB board is required to be within 10μm, then the predetermined value is set to 2μm. If the positioning mark is a positioning hole located on the chuck, then the distance between the positioning hole and the marking hole is set to be less than 20mm. During the PCB board exposure process, based on the thermal expansion coefficient of aluminum alloy, the material of the chuck, which is 23μm / ℃.m, and the temperature fluctuation range during the exposure process, which is ±2℃, the relative positional change between the positioning hole and the marking hole is 23*4*0.02=1.8μm<2μm. Furthermore, since the local rigidity of aluminum alloy is greater than the overall rigidity, the vacuum effect is very small when the distance between the positioning hole and the marking hole is small and can be ignored. Through actual testing, the relative positional change between the positioning hole and the marking hole meets the standard of less than the predetermined value of 2μm.

[0109] Similarly, if the positioning mark is a marker connected to the marking hole through an anti-deformation material, then since the anti-deformation material is minimally affected by temperature, the relative positional change between the positioning mark and the marking hole can be ignored.

[0110] In practical applications, anti-deformation materials can be made of materials with low coefficients of thermal expansion, such as Invar steel, marble, and ceramics. These materials are minimally affected by temperature. For example, the coefficient of thermal expansion of Invar steel is 0.8 μm / ℃ / m, that of marble is 5 μm / ℃ / m, and that of ceramics is 7 μm / ℃ / m. Even if the length of the anti-deformation material connecting the positioning mark and the marking hole is as long as 100 mm, its deformation within a temperature range of ±2℃ is 0.8*4*0.1=0.32 μm and 5 μm, respectively. *4*0.1=2μm, 7*4*0.1=2.8μm. Moreover, in practical applications, the anti-deformation material will not be 100mm long. For example, if the distance between the positioning mark and the marking hole is 10mm, then within a temperature change range of ±2℃, the deformation of the anti-deformation material will be 0.8*4*0.02=0.064μm, 5*4*0.02=0.4μm, and 7*4*0.02=0.56μm, respectively. Therefore, the relative positional change between the positioning mark and the marking hole can be ignored.

[0111] To achieve higher alignment accuracy, the distance between the positioning mark and the marking mark can be set to any value less than 20mm.

[0112] During the exposure process, the marking mark is selected according to the size of the PCB board; as shown in Figures 3, 4 and 5, any marking mark can be selected according to the size of the PCB board.

[0113] The marking mark can be placed anywhere on the suction cup.

[0114] During the exposure process, the CCD camera acquires the position information of the positioning marks. When exposing the other side of the PCB board, the position information of the marking holes is determined based on the position information of the positioning marks acquired by the CCD camera. Then, the position of the exposure pattern on the other side of the PCB board is determined based on the position information of the marking holes, and then the exposure is performed.

[0115] For ease of description, the two sides of the PCB board will be referred to as side A and side B, respectively.

[0116] For example, the initial calibration position of the marking hole recorded in the system is denoted as... The initial calibration position of the positioning mark is denoted as When exposing a PCB board, the real-time position of the positioning marker is recorded as follows: The CCD camera acquires the position change of the positioning marker relative to the initial position recorded in the system as follows:

[0117]

[0118]

[0119] Since the relative positional change between the positioning mark and the marking hole is negligible, it can be concluded that the positional change of the marking hole is also:

[0120]

[0121]

[0122] The theoretical value of the marking hole at the marked position on side B is denoted as...

[0123] When flipping the board up and down, the height of the PCB board is recorded as H, and the X coordinate of the bottom edge of the board is marked as X. bottom ;

[0124] Based on the theoretical value of the marking hole's position on side B, the expected position of the marking hole on side B is:

[0125] The actual location of the marking hole captured on side B after flipping the plate.

[0126] Alignment results

[0127] Exposure graphic A-side position Obtained through Y mirror

[0128] That is, the position of the graphic on side B is

[0129] This invention provides a double-sided exposure alignment device, including a positioning mark, a marking mark, and a position acquisition device. Before each sample is exposed, the position acquisition device acquires the position information of the positioning mark and then the position information of the marking mark. This determines the amount of change in the position of the marking mark relative to a predetermined position during the exposure of the sample. Based on this change, the position of the other side of the sample to be exposed is adjusted in real time. This solves the problem of inaccurate exposure alignment caused by the inability to perform real-time positioning of the marking mark in the prior art, and improves the accuracy of double-sided alignment of the sample to be exposed. By ensuring that the distance between the positioning mark and the marking mark is less than 20mm and / or by connecting them with an anti-deformation material, the relative positional change of the two during exposure is guaranteed to be less than the predetermined value set according to the alignment accuracy required for the exposure of the sample, thereby improving the accuracy of the double-sided alignment of the sample to be exposed. Before each sample to be exposed, the position information of the positioning mark is obtained through a position acquisition device, and then the position information of the marking mark is obtained, thereby determining the amount of change of the position of the marking mark relative to the predetermined position during the exposure of the sample. Based on this amount of change, the position of the predetermined exposure pattern on the other side of the sample to be exposed is adjusted in real time, thereby improving the accuracy of the double-sided alignment of the sample to be exposed.

[0130] Example 4

[0131] This embodiment provides an exposure apparatus including a double-sided exposure alignment device, as shown in Figure 6. The apparatus includes:

[0132] Positioning mark 11, marking mark 12, position acquisition device 13, sample carrying device 14, marking device 15, and exposure device 16;

[0133] The positioning mark 11 is used to determine the position of the marking mark 12 in real time, thereby determining the position of the exposure pattern of the sample to be exposed based on the position of the marking mark 12;

[0134] Marking mark 12 is used for marking the sample to be exposed;

[0135] Location acquisition device 13 is used to acquire the location information of the positioning marker in real time;

[0136] Exposure device 16 is used to expose the sample to be exposed;

[0137] The relative positional change of the positioning mark 11 and the marking mark 12 is less than a predetermined value, which is set according to the alignment accuracy required when the sample to be exposed is double-sided exposed; the distance between the positioning mark 11 and the marking mark 12 is less than 20mm and / or they are connected by an anti-deformation material.

[0138] The sample carrier 14 is used to carry the sample to be exposed; the marking device 15 is used to mark the sample to be exposed by the marking mark 12;

[0139] Marking mark 12 is located on sample carrier device 14.

[0140] This embodiment uses a PCB board as the sample to be exposed, a PCB board as the sample carrier device, a PCB board carrier suction cup made of aluminum alloy, a marking mark 12 as a marking hole on the PCB board, a CCD camera as the position acquisition device 13, and a 405 laser source as the marking device 15 for illustration.

[0141] Specifically, when the PCB board is placed on the chuck, it covers the marking hole so that the 405 laser source can mark the side of the PCB board facing that direction, ensuring that the PCB board is not covered by the positioning mark so that the CCD camera can obtain the position information of the positioning mark. The positioning mark can be a positioning hole on the chuck, the distance between the positioning hole and the marking hole is less than 20mm, or it can be a mark connected to the marking hole by an anti-deformation material, as long as the relative position change between the positioning mark and the marking hole during the operation is less than a predetermined value. This predetermined value is set according to the alignment accuracy required when the PCB board is exposed on both sides.

[0142] For example, if the alignment accuracy of the front and back sides of the PCB board is required to be within 10μm, then the predetermined value is set to 2μm. If the positioning mark is a positioning hole located on the chuck, then the distance between the positioning hole and the marking hole is set to be less than 20mm. During the PCB board exposure process, based on the thermal expansion coefficient of aluminum alloy, the material of the chuck, which is 23μm / ℃.m, and the temperature fluctuation range during the exposure process, which is ±2℃, the relative positional change of the positioning hole and the marking hole is 23*4*0.02=1.8μm<2μm. Furthermore, since the local rigidity of aluminum alloy is greater than the overall rigidity, the vacuum effect is very small when the distance between the positioning hole and the marking hole is small and can be ignored. Through actual testing, the relative positional change of the positioning hole and the marking hole meets the standard of less than the predetermined value of 2μm.

[0143] Similarly, if the positioning mark is a marker connected to the marking hole through an anti-deformation material, then since the anti-deformation material is minimally affected by temperature, the relative positional change between the positioning mark and the marking hole can be ignored.

[0144] In practical applications, materials with low coefficients of thermal expansion, such as Invar steel, marble, and ceramics, can be used to resist deformation. These materials are minimally affected by temperature. For example, Invar steel has a coefficient of thermal expansion of 0.8 μm / ℃ / m, marble has 5 μm / ℃ / m, and ceramics have 7 μm / ℃ / m. Even if the length of the anti-deformation material connecting the positioning mark and the marking hole is as long as 100 mm, its deformation within a temperature range of ±2℃ is 0.8*4*0.1=0.32 μm, 5*4*0.1=2 μm, and 7*4*0.1=2.8 μm, respectively. Moreover, in practical applications, the anti-deformation material will not be 100 mm long. For example, if the distance between the positioning mark and the marking hole is 10mm, then within a temperature range of ±2℃, the deformation of the deformation-resistant material is 0.8*4*0.02=0.064μm, 5*4*0.02=0.4μm, and 7*4*0.02=0.56μm, respectively. Therefore, the relative positional change between the positioning mark and the marking hole can be ignored.

[0145] To achieve higher alignment accuracy, the distance between the positioning mark and the marking mark can be set to any value less than 20mm.

[0146] During the exposure process, when the PCB board is placed on the carrier suction cup for exposure, at least two marking marks are selected according to the size of the PCB board; the marking marks are located at any part of the edge of the carrier suction cup, as shown in Figures 3, 4 and 5.

[0147] Cover the PCB board over the marking holes, but do not cover the positioning marks corresponding to the selected marking holes.

[0148] During the exposure process, the CCD camera acquires the position information of the positioning marks. When exposing the other side of the PCB board, the position information of the marking holes is determined based on the position information of the positioning marks acquired by the CCD camera. Then, the position of the exposure pattern on the other side of the PCB board is determined based on the position information of the marking holes, and then the exposure is performed.

[0149] For ease of description, the two sides of the PCB board will be referred to as side A and side B, respectively.

[0150] For example, the initial calibration position of the marking hole recorded in the system is denoted as... The initial calibration position of the positioning mark is denoted as When exposing a PCB board, the real-time position of the positioning marker is recorded as follows: The CCD camera acquires the position change of the positioning marker relative to the initial position recorded in the system as follows:

[0151]

[0152]

[0153] Since the relative positional change between the positioning mark and the marking hole is negligible, it can be concluded that the positional change of the marking hole is also:

[0154]

[0155]

[0156] The theoretical value of the marking hole at the marked position on side B is denoted as...

[0157] When flipping the board up and down, the height of the PCB board is recorded as H, and the X coordinate of the bottom edge of the board is marked as X. bottom ;

[0158] Based on the theoretical value of the marking hole's position on side B, the expected position of the marking hole on side B is:

[0159] The actual location of the marking hole captured on side B after flipping the plate.

[0160] Alignment results

[0161] Exposure graphic A-side position Obtained through Y mirror

[0162] That is, the position of the graphic on side B is

[0163] Actual testing shows that, with a system axis repeatability accuracy of 1μm and an image processing accuracy of 1μm, this invention can ensure precise positioning of both sides of the PCB inner layer holeless board within 10μm.

[0164] This invention provides a double-sided exposure alignment device, including a positioning mark, a marking mark, and a position acquisition device. Before each sample is exposed, a suitable marking mark is selected according to the size of the sample. The position acquisition device acquires the position information of the positioning mark corresponding to the selected marking mark, thereby determining the change in the position of the marking mark relative to a predetermined position during the exposure of the sample. Based on this change, the position of the other side of the sample to be exposed is adjusted in real time. This solves the problem of inaccurate exposure alignment caused by the inability to perform real-time positioning of the marking mark in the prior art, and improves the accuracy of double-sided alignment of the sample to be exposed. By ensuring that the distance between the positioning mark and the marking mark is less than 20mm and / or by connecting them with an anti-deformation material, the relative positional change of the two during exposure is guaranteed to be less than the predetermined value set according to the alignment accuracy required for the exposure of the sample, thereby improving the accuracy of the double-sided alignment of the sample to be exposed. Before each sample to be exposed, the position information of the positioning mark is obtained through a position acquisition device, and then the position information of the marking mark is obtained, thereby determining the amount of change of the position of the marking mark relative to the predetermined position during the exposure of the sample. Based on this amount of change, the position of the predetermined exposure pattern on the other side of the sample to be exposed is adjusted in real time, thereby improving the accuracy of the double-sided alignment of the sample to be exposed.

[0165] Example 5

[0166] This embodiment provides a double-sided exposure method, as shown in Figures 10 and 11.

[0167] As shown in Figure 10, the substrate 20 to be exposed is placed on the sample carrier 14, and at the same time, the position acquisition device 13 acquires the position information of the selected positioning mark 11.

[0168] As shown in Figure 11, the position information of the selected positioning mark 11 is obtained by the position acquisition device 13, and the positioning mark 21 is exposed on the substrate 20 to be exposed by the exposure device 16, so that the positioning mark 21 and the mark printed by the marking mark 12 are established in a one-to-one correspondence. At the same time, the positioning mark 21 is used as the graphic position positioning mark when the front side of the substrate is exposed, and the mark printed by the marking mark 12 is used as the graphic position positioning mark when the back side of the substrate is exposed. Therefore, the two sides of the graphic can establish a precise positional relationship.

[0169] For ease of description, the two sides of the PCB board will be referred to as side A and side B, respectively.

[0170] For example, the initial calibration position of the marking hole recorded in the system is denoted as... The initial calibration position of the positioning mark is denoted as When exposing a PCB board, the real-time position of the positioning marker is recorded as follows: The CCD camera acquires the position change of the positioning marker relative to the initial position recorded in the system as follows:

[0171]

[0172]

[0173] Since the relative positional change between the positioning mark and the marking hole is negligible, it can be concluded that the positional change of the marking hole is also:

[0174]

[0175]

[0176] The theoretical value of the marking hole at the marked position on side B is denoted as...

[0177] Exposure device 16 uses the theoretical value of the marked position on surface A. The positioning Mark 21 is exposed as an intermediate marker. The positioning Mark 21 is used to determine the pattern position when exposing the A side of the exposure substrate.

[0178] When flipping the board up and down, the height of the PCB board is recorded as H, and the X coordinate of the bottom edge of the board is marked as X. bottom ;

[0179] Based on the theoretical value of the marking hole's position on side B, the expected position of the marking hole on side B is:

[0180] The actual location of the marking hole captured on side B after flipping the plate.

[0181] Alignment results

[0182] Exposure graphic A-side position Obtained through Y mirror

[0183] That is, the position of the graphic on side B is

[0184] Actual testing shows that, with a system axis repeatability accuracy of 1μm and an image processing accuracy of 1μm, this invention can ensure precise positioning of both sides of the PCB inner layer holeless board within 10μm.

[0185] Some steps in the embodiments of the present invention can be implemented using software, and the corresponding software program can be stored in a readable storage medium, such as an optical disc or a hard disk.

[0186] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A double-sided exposure alignment device, characterized in that, The device includes: Positioning markers, marking markers, and location acquisition devices; The positioning mark is used to determine the position of the marking mark in real time, thereby determining the position of the exposure pattern of the sample to be exposed based on the position of the marking mark; The marking marks are used to mark the samples to be exposed; The location acquisition device is used to acquire the location information of the positioning marker in real time.

2. The apparatus according to claim 1, characterized in that, The relative positional change of the positioning mark and the marking mark is less than a predetermined value, which is set according to the alignment accuracy required when the sample to be exposed is subjected to double-sided exposure.

3. The apparatus according to claim 1, characterized in that, The distance between the positioning mark and the marking mark is less than 20 mm and / or they are connected by an anti-deformation material.

4. The apparatus according to claim 1, characterized in that, The device further includes: A sample carrier and a marking device; the sample carrier is used to carry the sample to be exposed; the marking device is used to mark the sample to be exposed using the marking mark; The marking mark is located on the sample carrier.

5. The apparatus according to claim 4, characterized in that, The marking mark is located on the edge of the sample carrier.

6. A method for aligning two-sided exposures, characterized in that, The method is applied to the above-mentioned alignment apparatus for double-sided exposure, and the method includes: Expose one side of the sample to be exposed; The other side of the sample to be exposed is marked by marking. Real-time acquisition of location information of positioning markers; The location information of the marking mark is determined based on the location information of the positioning mark obtained in real time; The other side of the sample to be exposed is aligned and exposed according to the position information of the marking mark.

7. The method according to claim 6, characterized in that, Before exposing one side of the sample to be exposed, the method further includes: The system acquires the position information of the positioning mark when exposing one side of the sample to be exposed in real time, and exposes an intermediate mark on one side of the sample to be exposed based on the acquired position information of the positioning mark. The intermediate mark is used to determine the position of the exposed pattern on its side.

8. The method according to claim 7, characterized in that, Before marking the other side of the sample to be exposed by marking, the method further includes: Select at least two marking marks according to the size of the sample to be exposed; The sample to be exposed is placed over the marking mark, but the positioning mark corresponding to the selected marking mark is not covered.

9. The method according to claim 8, characterized in that, The step of aligning and exposing the other side of the sample to be exposed according to the position information of the marking marks includes: The position of the exposure pattern on the other side of the sample to be exposed is determined in real time based on the position information of the marking marks; The other side of the sample to be exposed is exposed based on the position of the exposure pattern on the other side determined in real time.

10. An exposure apparatus, characterized in that, The exposure equipment includes the alignment device for double-sided exposure as described in any one of claims 1 to 5.