Circuit board with special-shaped quantity target and windowing method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGHE ELECTRONIC TECH (SHANDONG) CO LTD
- Filing Date
- 2026-02-11
- Publication Date
- 2026-04-14
Smart Images
Figure CN121865503A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of circuit board technology, and in particular to a circuit board with an irregularly shaped target and a method for opening a window. Background Technology
[0002] Lamination is a process in printed circuit board manufacturing that uses high temperature and high pressure to firmly bond multiple layers of materials into one piece.
[0003] During the lamination process, the substrate material inevitably undergoes deformation due to high temperature and pressure. Therefore, it is necessary to measure the impact of each hydraulic pressure condition on the substrate deformation. By comparing the changes in the coordinates of the patterned target before and after lamination using a patterned target, the substrate irregularity amount is calculated. Since the inner layer irregularity target is covered after lamination, it is necessary to open a window to re-expose the inner layer target. The existing windowing method uses laser windowing and sets four positioning target points around the circuit board, using the edge positioning target points to locate the patterned target.
[0004] However, the irregular shape after lamination is usually not a combination of rigid translation and rotation, but rather nonlinear stretching, local warping, and non-uniform deformation in the X / Y directions. The four positioning target points can only establish affine or simple distortion models, but the actual position of the inner layer pattern in the middle or local area still has deviations, and the central or edge targets may be burned off. Moreover, the positioning target points added around the inner layer pattern change the local copper distribution and resin flow path. The positioning target point area is more likely to generate stress concentration during lamination, and the local deformation is not synchronized with the main pattern, making the positioning target point the source of irregular shape. Summary of the Invention
[0005] To address the technical problem in the prior art where existing positioning target points around the circuit board are prone to becoming irregular shapes, affecting the accuracy of window positioning, this invention provides a circuit board with an irregularly shaped target and a windowing method.
[0006] The technical solution of this invention is as follows: This invention provides a circuit board with an irregularly shaped target, including an inner irregularly shaped target pattern disposed in the functional test area of the circuit board. The circuit board also has main positioning holes and an auxiliary positioning pattern group. The main positioning holes are disposed in the four corner areas of the circuit board. The auxiliary positioning pattern group includes a central auxiliary positioning pattern, an edge auxiliary positioning pattern, and a target-adjacent auxiliary positioning pattern. The central auxiliary positioning pattern is disposed at the geometric center of the circuit board and is used to reflect the irregularity in the central area of the board. The edge auxiliary positioning pattern is disposed in the middle area of the board edge between adjacent main positioning holes and is used to reflect the tensile or compressive irregularity in the board edge area. The target-adjacent auxiliary positioning pattern is disposed on the periphery of the inner irregularly shaped target pattern and is used to compensate for the irregularity in the local area of the target. Setting the inner layer irregularity target pattern in the functional test area eliminates the need for additional positioning target points and does not alter the local copper distribution and resin flow path of the circuit board. This fundamentally avoids stress concentration and asynchronous deformation caused by additional targets. Simultaneously, through multi-region and multi-type auxiliary positioning pattern groups, irregularity features at different locations such as the center of the circuit board, the edge of the board, and the periphery of the target can be captured in a targeted manner. This can comprehensively reflect the complex deformation conditions such as nonlinear stretching, local warping, and unequal X / Y ratios after substrate lamination, making the detection of irregularity more comprehensive and more in line with the actual deformation state.
[0007] Preferably, the distance between the auxiliary positioning pattern near the target and the corresponding inner-layer irregular target pattern is less than the distance between the inner-layer irregular target pattern and the nearest main positioning hole. The auxiliary positioning pattern near the target is set close to the inner-layer irregular target pattern, which can accurately capture the local irregular changes around the target, provide more realistic local data support for the irregularity compensation of the target position, effectively reduce the local position deviation caused by remote positioning, and improve the accuracy of target position positioning.
[0008] Preferably, the center auxiliary positioning pattern, the edge auxiliary positioning pattern, and the target proximity auxiliary positioning pattern are any one of the following: cross-shaped copper pattern, ring-shaped copper pattern, or other regular geometric feature patterns. Regular geometric feature patterns have clear and easily identifiable visual characteristics, which can be quickly and accurately captured by the detection equipment, reducing the error of coordinate recognition and providing a precise measured data basis for the subsequent establishment of the irregular quantity compensation model.
[0009] Preferably, the main positioning hole is used to establish board-level reference coordinates. The inner layer irregular quantity target pattern is located within the area enclosed by the main positioning hole. By relying on the main positioning hole to establish a unified board-level reference coordinate system, a standardized coordinate reference system is provided for the irregular quantity detection of the entire circuit board. This ensures that the coordinate data of the auxiliary positioning patterns in each area and the inner layer irregular quantity target pattern are consistent and comparable. At the same time, placing the inner layer irregular quantity target pattern within the area enclosed by the main positioning hole enables accurate positioning of the core area target and calculation of irregular quantity based on the reference coordinates.
[0010] Preferably, a copper reduction zone is set around the main positioning hole, which can effectively avoid stress concentration caused by uneven copper layer distribution around the positioning hole, reduce local deformation in the positioning hole area, and prevent the positioning hole from becoming a new source of irregularity. Before pressing, the main positioning hole is a blind hole structure, which can protect the positioning hole structure from damage in the high temperature and high pressure environment of pressing. After pressing, it is drilled to form a through hole, which allows the testing equipment to more conveniently and accurately identify the position of the positioning hole and improve the accuracy of the establishment of the reference coordinate.
[0011] A method of opening a window, comprising: Step 1: Press the circuit board with the irregularly shaped target together; Step 2: Use an X-RAY device to identify the actual positions of the main positioning holes and auxiliary positioning graphic groups, and record the measured coordinates. Utilizing the penetrating power of the X-RAY device, the actual positions of the main positioning holes and auxiliary positioning graphic groups that are covered after pressing can be accurately identified, effectively obtaining the real measured coordinates of each positioning mark. This provides accurate and comprehensive actual data support for the subsequent establishment of the irregular amount compensation model, avoiding coordinate data errors caused by insufficient accuracy of the identification device. Step 3: Establish board-level reference coordinates based on the main positioning holes, and combine them with the measured coordinates of the auxiliary positioning pattern group to establish a compensation model for the irregular amount of the inner layer pattern after lamination. Calculate the predicted coordinates of the inner layer irregular amount target pattern after lamination. First, establish board-level reference coordinates based on the main positioning holes to ensure that the compensation model has a unified coordinate reference. Then, combine the measured coordinates of the multi-region auxiliary positioning pattern group to ensure that the established irregular amount compensation model can fully integrate the irregular data of different regions such as the center of the substrate, the edge of the board, and the periphery of the target, accurately adapt to the complex nonlinear deformation of the substrate after lamination. The target prediction coordinates calculated by the model can fit the actual position of the target to the greatest extent and significantly reduce the target positioning deviation. Step 4: Before ablation, the laser equipment performs a low-power scan on the calculated position of the inner layer irregular target graphic and compares it with the predicted coordinates. When the verification result meets the preset deviation threshold, the laser ablation operation is performed. The addition of the low-power scan and coordinate comparison verification steps before laser ablation can actually verify the predicted coordinates calculated by the model and promptly detect the deviation between the predicted coordinates and the actual position. The ablation operation is only performed when the deviation meets the preset threshold. This avoids the target ablation problem caused by model prediction deviation from the operation process and improves the accuracy of laser windowing. Step 5: Complete the ablation of the outer copper foil and PP material to expose the inner irregular target pattern.
[0012] Preferably, in step 3, an affine transformation model is first established based on the main positioning hole to map the design coordinates to the actual coordinates after pressing. Then, based on the auxiliary positioning graphic group, a nonlinear irregular shape compensation model is established on the basis of the affine coordinates to output the predicted coordinates. First, the basic mapping from the design coordinates to the actual coordinates after pressing is achieved through the affine transformation model, completing the translation, rotation, and scaling deformation compensation of the substrate base. Then, a nonlinear irregular shape compensation model is established based on the auxiliary positioning graphic group. On the basis of the basic mapping, the nonlinear stretching, local warping, and unequal deformation in the X / Y direction of the substrate are further accurately compensated. Through the two-step modeling method, the compensation model has both the overall deformation adaptability at the board level and the ability to accurately capture local nonlinear irregular shape features, which greatly improves the accuracy of the target predicted coordinates.
[0013] The preferred affine transformation model is:
[0014] in, For design coordinates; The coordinates after pressing are shown; the transformation model translates, rotates and scales the design coordinate system through the coordinates of the four main positioning holes, where a, b, c, d, e, and f are the coefficients of the affine transformation matrix. Nonlinear irregular compensation model:
[0015]
[0016] in, To design coordinates, The output is the predicted coordinates. and This is a local nonlinear offset; For constant terms; The coefficient of the linear term; The coefficient of the linear term; The coefficient of the quadratic term; The cross term coefficient; These are the coefficients for the quadratic term. The affine transformation model, through fixed matrix coefficients and relying on four main positioning holes, achieves a comprehensive transformation from the design coordinate system to the actual coordinate system, laying a precise foundation for nonlinear compensation. The nonlinear irregular shape compensation model introduces first-order, quadratic, and cross-term coefficients, which can accurately fit the offset patterns of complex deformations such as nonlinear stretching, local warping, and unequal X / Y ratios that occur after substrate lamination. By quantifying the local nonlinear offset, the coordinates are precisely corrected, ensuring that the output predicted coordinates closely match the actual position of the target, thus achieving precise mathematical compensation for complex irregular shapes.
[0017] Preferably, in step 4, after acquiring the scanned image, the deviation between the scanned image and the predicted coordinates is calculated. The deviation calculation formula is as follows:
[0018] in, The actual target position coordinates are obtained through low-power laser scanning or imaging. These are the target coordinates predicted in step 3. The deviation calculation formula allows for the quantification of the deviation between the actual target coordinates obtained from low-power scanning and the model-predicted coordinates. This provides an objective and unified numerical standard for deviation judgment, avoiding errors caused by subjective judgment, accurately measuring the fit between the predicted coordinates and the actual position, and providing accurate numerical basis for deciding whether to perform the ablation operation.
[0019] Preferably, when When, the cauterization step is permitted; when When the deviation exceeds the threshold, the processing is stopped and an abnormal message is output. Setting a deviation threshold as the execution judgment standard for the burning operation can effectively control the error range of the target positioning and avoid the laser burning the target due to excessive deviation. When the deviation exceeds the threshold, the processing is stopped immediately and an abnormal message is output, which can terminate unqualified processing operations in time, reduce the waste of raw materials, and remind the staff to check the problem and ensure the overall quality of the window opening processing.
[0020] As can be seen from the above technical solutions, the advantages of the present invention are: 1. By setting the inner layer irregularity target pattern in the functional test area, there is no need to add additional positioning target points. This will not change the local copper distribution and resin flow path of the circuit board, thus avoiding stress concentration and local asynchronous deformation caused by adding additional targets. At the same time, through multi-area and multi-type auxiliary positioning pattern groups, the irregularity features of different positions in the center of the circuit board, the edge of the board, and the periphery of the target can be captured in a targeted manner. This can comprehensively reflect the complex deformation of nonlinear stretching, local warping, and unequal X / Y ratio after the substrate is laminated, making the detection of irregularity more comprehensive and more in line with the actual deformation state.
[0021] 2. First, the design coordinates are mapped to the actual coordinates after pressing using an affine transformation model to complete the translation, rotation, and scaling deformation compensation of the substrate base. Then, a nonlinear irregular shape compensation model is established based on the auxiliary positioning graphic group. On the basis of the basic mapping, the nonlinear stretching, local warping, and unequal deformation in the X / Y direction of the substrate are further accurately compensated. Through the two-step modeling method, the compensation model has both the overall deformation adaptability of the board level and the ability to accurately capture local nonlinear irregular shape features, which greatly improves the accuracy of the target prediction coordinates. Attached Figure Description
[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description 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.
[0023] Figure 1 This is a schematic diagram of the overall structure of a circuit board with an irregularly shaped target according to one or more embodiments of the present invention. Figure 2 This is a schematic flowchart of a window opening method according to one or more embodiments of the present invention; The components represented by the various reference numerals in the diagram are: 1. Circuit board; 2. Inner layer irregular target pattern; 3. Main positioning hole; 4. Center auxiliary positioning pattern; 5. Edge auxiliary positioning pattern; 6. Target adjacent auxiliary positioning pattern. Detailed Implementation
[0024] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.
[0025] Example 1 In a typical embodiment of the present invention, such as Figure 1As shown, a circuit board with an irregularly shaped measurement target is proposed, including: an inner irregularly shaped measurement target pattern 2, main positioning holes 3, and an auxiliary positioning pattern group. The inner irregularly shaped measurement target pattern 2, the main positioning holes 3, and the auxiliary positioning patterns are all set on the circuit board 1. The inner irregularly shaped measurement target pattern 2 is set in the functional test area of the circuit board 1 and is located inside the area enclosed by the main positioning holes 3. The inner irregularly shaped measurement target pattern 2 maintains a set safety distance from the board edge to avoid edge stress interference. There are four main positioning holes 3, which are located in the four corner areas of the circuit board 1. Each main positioning hole 3 is equidistant from the corresponding board edge. The four main positioning holes 3 form a rectangle or near-rectangular shape. The board is rectangular in shape, and the four main positioning holes 3 are symmetrically distributed with respect to the center of the board. The auxiliary positioning pattern group includes a central auxiliary positioning pattern 4, an edge auxiliary positioning pattern 5, and a target adjacent auxiliary positioning pattern 6. The central auxiliary positioning pattern 4 is set at or near the geometric center of the circuit board 1 to reflect the irregular shape in the central area of the board. The edge auxiliary positioning pattern 5 is set in the middle area of the board edge between adjacent main positioning holes 3 to reflect the stretching or compression irregular shape in the board edge area. The target adjacent auxiliary positioning pattern 6 is set around the inner layer irregular shape target pattern 2 and maintains a preset distance from the inner layer irregular shape target pattern 2 to compensate for the irregular shape in the local area of the target.
[0026] Setting the inner layer irregularity target pattern 2 in the functional test area eliminates the need for additional positioning target points and does not alter the local copper distribution and resin flow path of the circuit board 1. This fundamentally avoids stress concentration and local asynchronous deformation caused by additional targets. At the same time, through a multi-regional and multi-type auxiliary positioning pattern group, the irregularity features at different locations such as the center, edge, and periphery of the circuit board 1 are captured in a targeted manner. This can comprehensively reflect the complex deformation situation of nonlinear stretching, local warping, and unequal X / Y ratio after substrate lamination, making the detection of irregularity more comprehensive and more in line with the actual deformation state.
[0027] Specifically, a copper reduction area is set around the main positioning hole 3. The main positioning hole 3 is a circular hole structure with a diameter of 0.8mm-2.0mm. Before lamination, the main positioning hole 3 is a blind hole structure. After lamination, it is formed into a through hole by X-RAY drilling. There is at least one inner layer irregular measurement target pattern 2. When there is more than one, it is arranged in an array along the X direction and / or Y direction or symmetrically distributed around the center of the board. The inner layer irregular measurement target pattern 2 is any one of the cross-shaped circuit pattern, ring circuit pattern or rectangular closed circuit pattern, with a clear geometric center, which is convenient for identifying the center position by X-RAY or laser.
[0028] At least one target proximity auxiliary positioning pattern 6 is set around each inner layer irregular quantity target pattern 2. The distance between the target proximity auxiliary positioning pattern 6 and the corresponding inner layer irregular quantity target pattern 2 is less than the distance between the inner layer irregular quantity target pattern 2 and the nearest main positioning hole 3.
[0029] The center auxiliary positioning pattern 4, the edge auxiliary positioning pattern 5, and the target proximity auxiliary positioning pattern 6 are any one of the following: cross-shaped copper pattern, ring-shaped copper pattern, or other regular geometric feature patterns. They do not form through holes and do not participate in electrical connections, so as to have obvious geometric features under X-ray.
[0030] In this embodiment, the main positioning hole 3 is used to establish the plate-level reference coordinates. The inner layer irregular quantity target pattern 2 is located in the area enclosed by the main positioning hole 3. The auxiliary positioning pattern group is located between the main positioning hole 3 and the inner layer irregular quantity target pattern 2, and is set close to the inner layer irregular quantity target pattern 2. The main positioning hole 3, the auxiliary positioning pattern group and the inner layer irregular quantity target pattern 2 together constitute a multi-reference point irregular quantity test structure.
[0031] Example 2 In another typical embodiment of the present invention, such as Figure 2 As shown, a windowing method is proposed for windowing circuit boards with irregularly shaped measurement targets. The windowing method includes: Step 1: Pressing of circuit board 1; The circuit board 1, which includes the inner layer irregular target pattern 2, the main positioning hole 3, and the auxiliary positioning pattern group, is press-fitted to generate the actual irregular shape of the inner layer circuit pattern under hot pressing. The PP thickness is 80. -120 The PP resin content is 45%-55%, and the copper foil thickness is 12mm. Or 18 .
[0032] Step 2: After pressing is completed, use an X-RAY device to identify the actual position of the main positioning hole 3 and the auxiliary positioning graphic group, and record the measured coordinates; Specifically, the actual positions of the four main positioning holes 3 and the auxiliary positioning graphic group are read, the main positioning holes 3 are drilled, and the measured coordinates of all reference points are recorded.
[0033] Step 3: Based on the main positioning hole 3, establish the plate-level reference coordinates. Combined with the measured coordinates of the auxiliary positioning graphic group, establish the irregular amount compensation model of the inner layer graphic after pressing, and calculate the predicted coordinates of the inner layer irregular amount target graphic 2 after pressing. Specifically, an affine transformation model is established based on the main positioning hole 3 to complete overall translation, rotation, and linear scaling compensation, eliminate overall deformation, and transform the design coordinates. Mapped to actual coordinates after pressing The affine transformation model is:
[0034] in, Design coordinates refer to the ideal target graphic coordinates determined based on CAD or PCB design documents during the circuit board design stage, before lamination. The coordinates after pressing are shown. The transformation model translates, rotates, and scales the design coordinate system through the coordinates of the four main positioning holes 3. In the formula, a, b, c, d, e, and f are the coefficients of the affine transformation matrix, representing the transformation relationship from the design coordinate system to the actual coordinate system. Specifically, a and e represent the scaling coefficients in the x and y directions of the design coordinate system, respectively, controlling the scaling ratio of the transformed coordinates; b and d represent the rotation and tilt coefficients in the x and y directions of the design coordinate system, respectively, controlling the degree of rotation or bending; c and f are the translation coefficients, representing the translation amount in the x and y directions of the design coordinate system, that is, translating the origin to the actual pressed coordinates.
[0035] Using an auxiliary positioning graphic set, a nonlinear irregular shape compensation model is established based on affine coordinates to perform fine compensation on the target position. This model is used to compensate for local nonlinear deformation of the circuit board caused by pressing stress, material inhomogeneity, or thermal deformation. The nonlinear irregular shape compensation model is as follows:
[0036]
[0037] in, To design coordinates, The output is the predicted coordinates. and This is a local nonlinear offset; This is a constant term, representing the offset of the coordinates; The coefficient of the linear term represents the compensation for linear deformation; The coefficient of the first-order term represents linear deformation compensation in the other direction; The coefficient of the quadratic term represents the nonlinear deformation caused by the pressing process, especially the quadratic deformation. The cross term coefficient represents the coupling effect between the x and y directions; The coefficients are quadratic terms, and nonlinear deformation in the y-direction is further considered.
[0038] That is, the coefficients of the affine transformation matrix The main control is based on the translation, rotation, and scaling of the four main positioning holes 3, and the coefficients in the nonlinear irregular shape compensation model. To further correct the nonlinear deformation after pressing, all model coefficients were calculated using the least squares method.
[0039] After the model is built, its effectiveness is determined. Specifically, the model error is calculated using the following formula:
[0040] RMSE is used to measure the deviation between the model's predictions and the actual observations. A smaller RMSE indicates higher prediction accuracy. In this embodiment, when... When, the model is deemed valid; when If necessary, remodel or terminate subsequent processing; N is the number of reference points; The actual measured coordinates of each reference point are the actual position coordinates obtained through X-RAY or other methods; they are real, verified coordinate data. These are the predicted coordinates calculated by the nonlinear irregular compensation model.
[0041] First, an affine transformation model is used to achieve a basic mapping from the design coordinates to the actual coordinates after pressing, completing the translation, rotation, and scaling deformation compensation of the substrate base. Then, a nonlinear irregular shape compensation model is established based on the auxiliary positioning graphic group. On the basis of the basic mapping, the nonlinear stretching, local warping, and unequal deformation in the X / Y direction of the substrate are further accurately compensated. Through the two-step modeling method, the compensation model has both the overall deformation adaptability at the board level and the ability to accurately capture local nonlinear irregular shape features, which greatly improves the accuracy of the target prediction coordinates.
[0042] Step 4: Before ablation, the laser equipment performs a low-power scan on the calculated position of the inner layer irregular target pattern 2 and compares it with the predicted coordinates. When the verification result meets the preset deviation threshold, the laser ablation operation is performed. Specifically, before the formal laser ablation, the laser equipment performs a low-power scan on the calculated position of the inner layer irregular target pattern 2. After acquiring the scanned image, the deviation between the scanned image and the predicted coordinates is calculated. The deviation calculation formula is as follows:
[0043] in, To predict the deviation distance between the target position and the actual scanned image; These are the actual target position coordinates obtained through low-power laser scanning or imaging, i.e., the measured coordinates of the target on the board in the scanned image. In this embodiment, when... When, the cauterization step is permitted; when When this occurs, processing is stopped and an error message is output; These are the target coordinates predicted in step 3, which are the theoretically calculated target positions after compression.
[0044] Step 5: Complete the ablation of the outer copper foil and PP material to expose the inner irregular target pattern 2.
[0045] Calculate the local PP thickness based on the X-RAY grayscale value G:
[0046] in, These are pre-calibrated coefficients.
[0047] Calculate the laser ablation energy based on the PP thickness and copper foil thickness:
[0048] in, The value range is 0.8-1.2; The value range is 1.5-2.0; The value range is 10-15; This refers to the thickness of the outer copper foil.
[0049] The number of laser scans is determined based on the PP thickness.
[0050] The laser reflection signal is monitored in real time during the burning process. When the copper layer reflection characteristics are detected to reach a preset threshold, the burning is automatically terminated to prevent overburning.
[0051] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A circuit board with an irregularly shaped target, comprising: The inner layer irregular quantity target pattern (2) set in the functional test area of the circuit board (1) is characterized in that the circuit board (1) is also provided with a main positioning hole (3) and an auxiliary positioning pattern group. The main positioning hole (3) is set in the four corner areas of the circuit board (1). The auxiliary positioning pattern group includes a central auxiliary positioning pattern (4), an edge auxiliary positioning pattern (5) and a target adjacent auxiliary positioning pattern (6). The central auxiliary positioning pattern (4) is set at the geometric center of the circuit board (1) and is used to reflect the irregular quantity in the central area of the board. The edge auxiliary positioning pattern (5) is set in the middle area of the board edge between adjacent main positioning holes (3) and is used to reflect the stretching or compression irregularity in the board edge area. The target adjacent auxiliary positioning pattern (6) is set on the periphery of the inner layer irregular quantity target pattern (2) and is used to compensate for the irregular quantity in the local area of the target.
2. The circuit board with an irregularly shaped target according to claim 1, characterized in that, The distance between the target's adjacent auxiliary positioning pattern (6) and the corresponding inner layer irregular quantity target pattern (2) is less than the distance between the inner layer irregular quantity target pattern (2) and the nearest main positioning hole (3).
3. The circuit board with an irregularly shaped target according to claim 1, characterized in that, The center auxiliary positioning pattern (4), the edge auxiliary positioning pattern (5), and the target proximity auxiliary positioning pattern (6) are any one of the following: cross-shaped copper pattern, ring-shaped copper pattern, or other regular geometric feature patterns.
4. The circuit board with an irregularly shaped target according to claim 1, characterized in that, The main positioning hole (3) is used to establish the plate-level reference coordinates, and the inner layer irregular target pattern (2) is located in the area enclosed by the main positioning hole (3).
5. The circuit board with an irregularly shaped target according to claim 1, characterized in that, A copper reduction zone is set around the main positioning hole (3). The main positioning hole (3) is a blind hole structure before pressing, and is drilled to form a through hole after pressing.
6. A method for opening a window, characterized in that, include: Step 1: Press the circuit board with the irregularly shaped target as described in any one of claims 1-5; Step 2: Use an X-RAY device to identify the actual positions of the main positioning hole (3) and the auxiliary positioning graphic group, and record the measured coordinates; Step 3: Based on the main positioning hole (3), establish the plate-level reference coordinates, and combine the measured coordinates of the auxiliary positioning graphic group to establish the irregular amount compensation model of the inner layer graphic after pressing, and calculate the predicted coordinates of the inner layer irregular amount target graphic (2) after pressing. Step 4: Before ablation, the laser device performs a low-power scan on the calculated inner layer irregular target pattern (2) and compares it with the predicted coordinates. When the verification result meets the preset deviation threshold, the laser ablation operation is performed. Step 5: Complete the ablation of the outer copper foil and PP material to expose the inner irregular target pattern (2).
7. The window opening method according to claim 6, characterized in that, In step 3, firstly, an affine transformation model is established based on the main positioning hole (3) to map the design coordinates to the actual coordinates after pressing; then, based on the auxiliary positioning graphic group, a nonlinear irregular compensation model is established on the basis of the affine coordinates to output the predicted coordinates.
8. The window opening method according to claim 7, characterized in that, The affine transformation model is: in, For design coordinates; The coordinates after pressing are: The transformation model translates, rotates and scales the design coordinate system through the coordinates of the four main positioning holes (3), where a, b, c, d, e, and f are the coefficients of the affine transformation matrix; Nonlinear irregular compensation model: in, To design coordinates, The output is the predicted coordinates. and This is a local nonlinear offset; For constant terms; The coefficient of the linear term; The coefficient of the linear term; The coefficient of the quadratic term; The cross term coefficient; The coefficient of the quadratic term.
9. The window opening method according to claim 6, characterized in that, In step 4, after acquiring the scanned image, the deviation between the scanned image and the predicted coordinates is calculated. The deviation calculation formula is as follows: in, The actual target position coordinates are obtained through low-power laser scanning or imaging. These are the target coordinates predicted in step 3.
10. The window opening method according to claim 9, characterized in that, when When, the cauterization step is permitted; when When the error occurs, processing is stopped and an error message is output.