Circuit board structure and method for improving alignment precision capability between circuit board pressing layers

Abstract

The invention discloses a circuit board structure and method for improving the alignment precision capability between circuit board lamination layers, and the circuit board structure improves the board edge design of an existing circuit board which needs to be laminated, and on the basis of an existing Pi < n-1 > am positioning hole, the alignment precision capability between the lamination layers of the circuit board is improved. And a plurality of conductive blocks capable of heating and pre-fusing prepregs after being electrified are arranged on the edge of the plate. According to the method, the circuit board A and the circuit board B are manufactured according to the circuit board structure, the X-ray irradiation function is utilized firstly, and the T-face target and the B-face target on the circuit board A and the circuit board B are accurately recognized and matched when alignment between circuit board pressing layers is carried out, so that high-precision automatic alignment is achieved. And the electromagnetic hot melting function of the two vacuum table boards is started, so that the conductive blocks designed on the circuit board A and the conductive blocks designed on the circuit board B are used as fixing points to be fused with the prepregs respectively, the relative positions between layers can be kept unchanged in the fusion process, preliminary positioning is achieved, and the alignment precision is further improved. And after the preliminary fusion positioning, the Pi < n-1 > am positioning holes are utilized to carry out Pi < n-1 > am lamination on the whole, so that higher alignment precision among the layers in the lamination process is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board processing, and in particular to a circuit board structure and method for improving the alignment accuracy capability between lamination layers of a circuit board. Background Art

[0002] In the manufacturing process of multi-layer circuit boards (MLB), especially for high-density multi-layer circuit boards with N+N structures, the alignment accuracy between the lamination layers is a key factor in ensuring product performance and quality. With the rapid development of electronic technology, the integration of electronic products is getting higher and higher, the number of layers of circuit boards is increasing, and the requirements for inter-layer alignment accuracy are becoming increasingly stringent. At present, the Pin-Lam (Pin Lamination) method widely used in the industry is an effective lamination positioning technology, which achieves accurate alignment of multi-layer boards by setting PIN holes on the edge of the board. This method can meet production needs when the number of multi-layer boards is small and the alignment accuracy requirements are relatively loose, such as ≥3mil. However, with the increase in the number of product layers and the improvement of alignment accuracy requirements, such as requiring inter-layer offset ≤2mil, or even 1mil, the limitations of the Pin-Lam method are gradually emerging.

[0003] China Publication No. CN111800959A discloses a fusion riveting method for improving the interlayer alignment accuracy of a circuit board. Before processing the positioning hole, the target on the A side and the target on the B side are identified at the same time, and the midpoint of the line connecting the target on the A side and the target on the B side is used as the center of the positioning hole. The deviation between the positioning hole and the center of the target on the A side or the center of the target on the B side is less than 0.025 mm. The positioning hole can take into account the deviation of the A and B surface layers, reduce the misalignment problem of the A and B surfaces of a single core board, and cause the concentricity difference of the final product, improve the interlayer alignment accuracy of the multilayer printed circuit board pressed at one time, reduce the scrap rate of the circuit board caused by the positioning hole, and avoid causing great waste. However, the above method still cannot meet the needs for high-density multi-layer circuit boards with N+N structure and high precision.

[0004] Therefore, how to overcome the above-mentioned defects has become an important issue to be solved urgently by those skilled in the art. Summary of the invention

[0005] The present invention overcomes the shortcomings of the above-mentioned technology and provides a method and structure for manufacturing an IC carrier.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention discloses a circuit board structure for improving the alignment accuracy between the pressed layers of the circuit board, including a circuit board, wherein the circuit board is designed with multiple T-surface targets 1 on the top layer of the board edge, and multiple B-surface targets 2 corresponding to the positions of the T-surface targets 1 are designed on the bottom layer, and multiple conductive blocks 3 are arranged on the board edge that can heat and pre-fuse the semi-cured sheet after power is turned on, and multiple Pinl am positioning holes 4 are arranged at other positions on the board edge.

[0008] Preferably, the conductive block 3 is a copper block, and a plurality of conductive blocks 3 are evenly spaced along the edge of the circuit board.

[0009] Preferably, the conductive block 3 has a size of 8*8 mm.

[0010] Preferably, the T-plane target 1 and the B-plane target 2 are arranged on the inner side of a square ring formed by connecting multiple conductive blocks 3; the T-plane target 1 is in the shape of a circular ring, and each T-plane target 1 is provided with a B-plane target 2 in the shape of a solid circle in its circular ring, and the centers of the T-plane target 1 and the B-plane target 2 coincide.

[0011] Preferably, the T-surface target 1 is a non-conductive ring, and the B-surface target 2 is a circular copper PAD.

[0012] Preferably, the inner ring diameter of the T-surface target 1 is 3 mi l, and the diameter of the B-surface target 2 is 1 mi l.

[0013] Preferably, a plurality of T-surface targets 1 on the same side, a plurality of B-surface targets 2 on the same side, and a plurality of Pinl am positioning holes 4 on the same side are all arranged in parallel.

[0014] Preferably, the circuit board is provided with a conductive block 3 at each of the four corners at the edge of the board, and one or more conductive blocks 3 are evenly arranged on the long side of the circuit board; the circuit board is provided with two T-surface targets 1 at the corners of the short side of one side, and two T-surface targets 1 are symmetrically arranged on the short side of the other side; a Pinl am positioning hole 4 is arranged at the midpoint of the line connecting the two T-surface targets 1 on the same short side.

[0015] In a second aspect, the present invention provides a method for improving the alignment accuracy of lamination layers of a circuit board, comprising the following steps:

[0016] Step A, preparing a circuit board A on which circuits have been fabricated and a circuit board B on which circuits have been fabricated, wherein the circuit board A and the circuit board B adopt the circuit board structure described in the first aspect;

[0017] Step B: first place the circuit board A with the circuits made on a vacuum table with X-ray function and electromagnetic hot melting function;

[0018] Step C, pre-stack the prepreg on the circuit board A;

[0019] Step D: Use another vacuum table with electromagnetic hot melting function to suck up the circuit board B with the circuits made, and irradiate it with X-ray to automatically align it with the circuit board A according to the target;

[0020] Step E: Turn on the electromagnetic hot-melt function of the two vacuum tables to fuse the circuit board A, the prepreg, and the circuit board B to achieve preliminary positioning;

[0021] Step F: After fusion, the whole is subjected to Pinl am pressing to obtain a multi-layer circuit board.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The circuit board structure of this case is an improvement on the existing circuit board edge design that needs to be pressed. Based on the existing Pinl am positioning holes, multiple conductive blocks that can heat and pre-fuse the semi-cured sheets after power is turned on are set on the board edge, so that when the above circuit board structure is used for the inter-layer alignment of the circuit board pressing, the electromagnetic hot-melt technology can be used for alignment. The equipment table adopts an electromagnetic hot-melt structure, which can electromagnetically fuse the edge of the circuit board after the pre-stacked semi-cured sheets, which helps to maintain the stability and consistency between the layers during the pressing process. In addition, the design of the T-side target and the B-side target allows the subsequent circuit board to monitor and correct the alignment between the layers when the circuit board is used for pressing, so as to intuitively judge whether there is an alignment deviation between the layers by comparing the relative positions of the T-side target and the B-side target, and make adjustments in time.

[0024] The Pinl am positioning holes are still retained to provide precise positioning references during the lamination process, ensuring precise alignment between layers.

[0025] 2. In this case, the T-side target and the B-side target are set on the inner side of the square ring formed by the connection lines of multiple conductive blocks. The target and the conductive block can be staggered to reduce the influence on each other, ensure the requirement of alignment accuracy, and avoid unnecessary waste of space. The circular T-side target provides a clear boundary, which is convenient for identification and positioning during the lamination process. At the same time, the internal circular B-side target serves as a more accurate alignment point, further improving the accuracy of positioning. The design of overlapping center of circle ensures the precise correspondence between the T-side target and the B-side target, and can more easily achieve accurate alignment between layers during multi-layer lamination. Moreover, the combination design of the circular ring and the circular target in this case is more visually intuitive, reducing recognition errors and confusion caused by high shape similarity, allowing the automatic alignment system to more accurately identify and lock the target position, ensuring the accuracy of alignment, thereby improving the alignment accuracy between subsequent circuit board lamination layers. In this case, the B-side target is designed as a solid circle shape as the core point of alignment. On the one hand, the solid area of ​​the circular B-side target is relatively large, providing more identification information, making it clearer and more specific during the X-RAY recognition process, which is beneficial to improving the stability of the alignment process and thus reducing alignment deviation.

[0026] 3. The circuit board structure of this case is helpful to achieve high-precision alignment in the multi-layer lamination and manufacturing process by setting multiple T-side targets, multiple B-side targets, and multiple Pinl am positioning holes in parallel on the same side. Specifically, the conductive blocks set at the four corners of the edge of the circuit board can ensure that the circuit board can be accurately aligned through the four corners. By symmetrically setting targets on both sides of the short side of the circuit board, symmetry can be ensured during the manufacturing process, which is conducive to the precise control of inter-layer alignment. In addition, since the short side is shorter, setting targets on the short side makes it easier to achieve high-precision alignment operations, thereby effectively controlling the alignment accuracy.

[0027] 3. The method of this case manufactures circuit board A and circuit board B according to the circuit board structure of the first aspect, so that circuit board A and circuit board B have T-surface targets, B-surface targets, conductive blocks and Pinl am positioning holes, and can first use the X-ray irradiation function to accurately identify and match the T-surface targets and B-surface targets on circuit board A and circuit board B when aligning the layers of the circuit board. The setting of the T-surface targets and B-surface targets provides multiple precise reference points, and these targets can be clearly identified under X-ray irradiation, thereby achieving high-precision automatic alignment. Then, the electromagnetic hot melting function of the two vacuum tables is turned on through step E so that the conductive blocks designed on circuit board A and the conductive blocks designed on circuit board B are respectively fused with the semi-cured sheet as fixed points, which can ensure that the relative position between the layers remains unchanged during the fusion process to achieve preliminary positioning, thereby improving the alignment accuracy. In addition to target alignment and electromagnetic hot melt fusion, after the initial fusion positioning, through the setting of step F, the whole is Pinl am pressed using Pinl am positioning holes to ensure higher alignment accuracy between the layers during the pressing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the board edge structure design of the circuit board structure of the first embodiment of this case.

[0029] Figure 2 It is an enlarged schematic diagram of a certain part of the circuit board structure including a T-side target and a B-side target in the first embodiment of the present case.

[0030] Figure 3 It is a flow chart of the second embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of the N+N structure circuit board layout implemented based on the method of the second embodiment;

[0032] Wherein: 1-T surface target, 2-B surface target, 3-conductive block, 4-Pi nl am positioning hole, 100-circuit board A, 200-circuit board B, 300-first vacuum table, 400-prepreg sheet, 500-second vacuum table; DETAILED DESCRIPTION

[0033] The features of the present invention and other related features are further described in detail below through embodiments to facilitate understanding by those skilled in the art:

[0034] Embodiment 1

[0035] like Figure 1 and Figure 2As shown, a circuit board structure for improving the alignment accuracy between circuit board lamination layers includes a circuit board, wherein the circuit board is respectively designed with a plurality of T-surface targets 1 on the top layer of the board edge, and a plurality of B-surface targets 2 corresponding to the positions of the T-surface targets 1 on the bottom layer, and a plurality of conductive blocks 3 are arranged on the board edge, which can heat and pre-fuse the semi-cured sheet after power is turned on, and a plurality of Pinl am positioning holes 4 are arranged on the rest of the board edge.

[0036] As described above, this case improves the existing circuit board edge design that needs to be pressed. Based on the existing Pinl am positioning holes 4, multiple conductive blocks 3 that can heat and pre-fuse the semi-cured sheets after power is turned on are set on the board edge, so that when the above circuit board structure is used for the inter-layer alignment of the circuit board pressing, the electromagnetic hot melt technology can be used for alignment. The equipment table adopts an electromagnetic hot melt structure, which can electromagnetically fuse the edge of the circuit board after the pre-stacked semi-cured sheets, which helps to maintain the stability and consistency between the layers during the pressing process. In addition, the design of the T-side target and the B-side target allows the subsequent circuit board to monitor and correct the alignment between the layers when the circuit board is used for pressing, so as to intuitively judge whether there is an alignment deviation between the layers by comparing the relative positions of the T-side target and the B-side target, and make adjustments in time.

[0037] The setting of the Pinl am positioning hole 4 is still retained to further provide an accurate positioning reference during the lamination process, thereby ensuring accurate alignment between the layers.

[0038] As a preferred embodiment, the conductive block 3 is a copper block, and a plurality of conductive blocks 3 are evenly spaced along the edge of the circuit board. In this way, the conductive block is a copper block. As an excellent thermal conductive material, the copper block can quickly and evenly transfer heat, ensure uniform conductivity along the edge of the circuit board, and produce uniform heat distribution, which helps to achieve uniform softening and fusion of the prepreg, thereby improving the bonding quality and consistency between layers. Moreover, evenly spacing the conductive blocks at the edge of the board helps to disperse the stress generated during the lamination process, so as to reduce interlayer deformation or damage caused by stress concentration, thereby improving the overall stability and reliability of the circuit board.

[0039] As a preferred embodiment, the size of the conductive block 3 is 8*8mm. Thus, by designing the size of the conductive block 3 to be 8*8mm, it is possible to generate a precise conductive heating area at the edge of the circuit board on the basis of a smaller size design. On the one hand, it is convenient to realize local and precise fusion control during the lamination process to avoid unnecessary thermal stress on the entire circuit board; on the other hand, it is convenient to place the conductive block more accurately in the area that needs pre-fusion, thereby improving the accuracy of inter-layer alignment. In addition, precise control of the size of the conductive block 3 helps to reduce production costs.

[0040] like Figure 1 As shown, in a specific implementation, the T-plane target 1 and the B-plane target 2 are arranged on the inner side of a square ring formed by connecting a plurality of conductive blocks 3; the T-plane target 1 is in the shape of a circular ring, and each T-plane target 1 is provided with a corresponding B-plane target 2 in the shape of a solid circle in its circular ring, and the centers of the T-plane target 1 and the B-plane target 2 coincide with each other.

[0041] As mentioned above, the T-side target 1 and the B-side target 2 are arranged on the inner side of the square ring formed by the connection lines of multiple conductive blocks 3. The target and the conductive block can be staggered to reduce the influence on each other, ensure the positioning accuracy requirements, and avoid unnecessary waste of space. The circular ring-shaped T-side target 1 provides a clear boundary, which is convenient for identification and positioning during the lamination process. At the same time, the internal circular B-side target 2 serves as a more precise alignment point, further improving the accuracy of positioning. The design of overlapping center of circle ensures the precise correspondence between the T-side target 1 and the B-side target 2, which makes it easier to achieve precise alignment between layers during multi-layer lamination. Specifically, in the prior art, both targets are designed to be ring-shaped, with a small ring nested inside a large ring. The boundary between the two rings may cause visual confusion during the automatic identification and alignment process, which may easily lead to identification errors, thereby affecting the alignment accuracy between the laminated layers of the circuit board. Moreover, the combination design of the ring and the circle target in this case is more visually intuitive, reducing the identification errors and confusion caused by the high similarity of the shapes, so that the automatic alignment system can more accurately identify and lock the target position, ensuring the accuracy of the alignment, thereby improving the alignment accuracy between the subsequent laminated layers of the circuit board. In this case, the B-side target 2 is designed to be a solid circle shape as the core point of alignment. On the one hand, the solid area of ​​the circular B-side target 2 is relatively large, providing more identification information, so that it is clearer and more specific during the X-RAY identification process, which is conducive to improving the stability during the alignment process, thereby reducing alignment deviations.

[0042] As an optional embodiment, the T-side target 1 is a non-conductive ring, and the B-side target 2 is a circular copper PAD. In this way, the non-conductive ring as the T-side target 1, with its clear boundary and clear shape, helps to achieve high-precision positioning in the multi-layer lamination process, and because it is non-conductive, it will not interfere with the normal operation of the circuit, ensuring the accuracy of positioning. The B-side target 2 is designed as a circular copper PAD, so that the B-side target 2 has a higher reflectivity and a significant contrast with the surrounding non-conductive materials, so that the copper PAD can be more easily captured and recognized by the recognition system, thereby improving the accuracy and stability of recognition.

[0043] As an optional implementation, the inner ring diameter of the T-surface target 1 is 3mil, and the diameter of the B-surface target 2 is 1mil. In this way, a gap of 1mil is left between the inner ring of the T-surface target 1 and the circular outer edge of the B-surface target 2, which can accommodate the deviations that may occur during the actual production of the T-surface and the B-surface; and the smaller diameter of the B-surface target 2 makes it easier to achieve high-precision alignment during the alignment process, which can meet the current requirement of interlayer offset ≤2mil, ensuring the precision and accuracy of target identification.

[0044] like Figure 1 As shown, multiple T-surface targets 1, multiple B-surface targets 2, and multiple Pinl am positioning holes 4 on the same side are all arranged in parallel. Thus, by requiring the T-surface targets, B-surface targets, and Pinl am positioning holes to be arranged in parallel on the same side, this layout helps to maintain stability and consistency between layers during the lamination process and avoid misalignment and offset.

[0045] As an optional embodiment, the circuit board is provided with a conductive block 3 at each of the four corners of the edge of the board, and one or more conductive blocks 3 are evenly arranged on the long side of the circuit board; the circuit board is provided with two T-surface targets 1 at the corners of the short side of one side, and two T-surface targets 1 are symmetrically arranged on the short side of the other side; a Pinl am positioning hole 4 is provided at the midpoint of the line connecting the two T-surface targets 1 on the same short side.

[0046] As described above, by defining multiple T-surface targets 1, multiple B-surface targets 2, and multiple Pinl am positioning holes 4 on the same side and setting them in parallel, it is helpful to achieve high-precision alignment in the multi-layer lamination and manufacturing process. Specifically, the conductive blocks 3 set at the four corners of the edge of the circuit board can ensure that the circuit board can be accurately aligned through the four corners. By symmetrically setting targets on the short sides of the circuit board on both sides, the symmetry in the manufacturing process can be ensured, which is conducive to the precise control of the inter-layer alignment. In addition, since the short side is short, setting targets on the short side makes it easier to achieve high-precision alignment operations, thereby effectively controlling the alignment accuracy.

[0047] Embodiment 2

[0048] like Figure 3 and Figure 4 As shown, a method for improving the alignment accuracy between lamination layers of a circuit board comprises the following steps:

[0049] Step A, preparing a circuit board A on which circuits have been fabricated and a circuit board B on which circuits have been fabricated, wherein the circuit board A and the circuit board B adopt the circuit board structure described in the first embodiment;

[0050] Step B, firstly place the circuit board A with the circuits fabricated on a vacuum table with X-ray function and electromagnetic heat melting function; the vacuum table with X-ray function and electromagnetic heat melting function is recorded as the first vacuum table 300;

[0051] Step C, pre-stack the prepreg 400 on the circuit board A;

[0052] Step D: Use another vacuum table with electromagnetic heat-melting function to suck up the circuit board B with the circuits made, and irradiate it with X-ray to automatically align it with the circuit board A according to the target; the other vacuum table with electromagnetic heat-melting function is recorded as the second vacuum table 500;

[0053] Step E: Turn on the electromagnetic hot-melt function of the two vacuum tables to fuse the circuit board A, the prepreg, and the circuit board B to achieve preliminary positioning;

[0054] Step F, turning off the electromagnetic hot-melt function, that is, performing Pinl am pressing on the whole after fusion to obtain a multi-layer circuit board.

[0055] In specific implementation, the electromagnetic hot melting function refers to using the principle of electromagnetic induction to convert electrical energy into thermal energy to melt the metal material in the workpiece, thereby achieving the purpose of welding.

[0056] As described above, the method of this case manufactures circuit board A and circuit board B according to the circuit board structure of embodiment one, so that circuit board A and circuit board B have T-side target 1, B-side target 2, conductive block 3 and Pinl am positioning hole 4. When aligning the circuit board lamination layers, the X-ray irradiation function is first used to accurately identify and match the T-side target 1 and the B-side target 2 on circuit board A and circuit board B. The setting of the T-side target 1 and the B-side target 2 provides multiple precise reference points, which can be clearly identified under X-ray irradiation, thereby achieving high-precision automatic alignment. Then, through step E, the electromagnetic hot-melt function of the two vacuum tables is turned on, and the electromagnetic induction principle is used to enable the conductive block 3 designed on the circuit board A and the conductive block 3 designed on the circuit board B to generate heat, so that the local material of the semi-cured sheet is softened or melted, thereby achieving the initial positioning between the layers, so that the heating area can be accurately controlled, and the precise alignment between the layers can be achieved without damaging the surrounding materials, which provides a good foundation for the subsequent Pinl am pressing, reduces the risk of misalignment during the pressing process, and thus improves the alignment accuracy. In addition, in addition to the target alignment and electromagnetic hot-melt fusion, after the initial fusion positioning, the Pinl am positioning hole 4 is used to perform Pinl am pressing on the whole through the setting of step F to ensure that the layers achieve a higher alignment accuracy during the pressing process.

[0057] In summary, the present invention proposes a new circuit board structure and a new method for improving the inter-layer alignment accuracy of the circuit board, by designing a T-side target on the top layer of the circuit board edge and a B-side target on the bottom layer, and using electromagnetic hot melt technology to allow the conductive block to heat and pre-fuse the prepreg, and designing Pinl am positioning holes, so as to achieve high-precision alignment of the multi-layer circuit board during the lamination process. This structure and method combine the traditional Pinl am method and the accurate identification of the target, effectively improving the inter-layer alignment accuracy.

[0058] As described above, this case protects a circuit board structure and method that improves the alignment accuracy between the lamination layers of the circuit board. All technical solutions that are the same or similar to this case should be deemed to fall within the scope of protection of this case.

Claims

1. A circuit board structure for improving the alignment accuracy between lamination layers of a circuit board, comprising a circuit board, characterized in that: The circuit board is respectively designed with a plurality of T-surface targets (1) on the top layer of the board edge, and a plurality of B-surface targets (2) corresponding to the positions of the T-surface targets (1) on the bottom layer, and is provided with a plurality of conductive blocks (3) on the board edge that can generate heat to pre-fuse the prepreg after power is turned on, and a plurality of Pin-lam positioning holes (4) are provided at other positions of the board edge.

2. The circuit board structure according to claim 1, characterized in that: The conductive block (3) is a copper block, and a plurality of conductive blocks (3) are evenly spaced and arranged along the edge of the circuit board.

3. The circuit board structure according to claim 2, characterized in that: The conductive block (3) has a size of 8*8 mm.

4. The circuit board structure according to any one of claims 1, characterized in that: The T-plane target (1) and the B-plane target (2) are arranged on the inner side of a square ring formed by connecting a plurality of conductive blocks (3); the T-plane target (1) is in the shape of a circular ring, and each T-plane target (1) is provided with a corresponding B-plane target (2) in the shape of a solid circle in its circular ring, and the centers of the T-plane target (1) and the B-plane target (2) coincide with each other.

5. The circuit board structure according to claim 4, characterized in that: The T-surface target (1) is a non-conductive ring, and the B-surface target (2) is a circular copper PAD.

6. The circuit board structure according to claim 4 or 5, characterized in that: The inner ring diameter of the T-surface target (1) is 3 mil, and the diameter of the B-surface target (2) is 1 mil.

7. The circuit board structure according to claim 1, characterized in that: A plurality of T-surface targets (1) on the same side, a plurality of B-surface targets (2) on the same side, and a plurality of Pin-lam positioning holes (4) on the same side are all arranged in parallel.

8. The circuit board structure according to claim 1 or 7, characterized in that: The circuit board is provided with one of the conductive blocks (3) at the four corners of the edge of the board, and one or more conductive blocks (3) are evenly arranged on the long side of the circuit board; the circuit board has two T-surface targets (1) at the corners of the short side of one side, and two T-surface targets (1) are symmetrically arranged on the short side of the other side; and a Pin-lam positioning hole (4) is arranged at the midpoint of the line connecting the two T-surface targets (1) on the same short side.

9. A method for improving the alignment accuracy of circuit board lamination layers, characterized in that: The steps include: Step A, preparing a circuit board A with circuits already made and a circuit board B with circuits already made, wherein the circuit board A and the circuit board B adopt the circuit board structure according to any one of claims 1 to 8; Step B: first place the circuit board A with the circuits made on a vacuum table with X-ray function and electromagnetic hot melting function; Step C, pre-stack the prepreg on the circuit board A; Step D: Use another vacuum table with electromagnetic hot melting function to suck up the circuit board B with the circuits made, and irradiate it with X-ray to automatically align it with the circuit board A according to the target; Step E: Turn on the electromagnetic hot-melt function of the two vacuum tables to fuse the circuit board A, the prepreg, and the circuit board B to achieve preliminary positioning; Step F: After fusion, the whole is pin-laminated to obtain a multi-layer circuit board.

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