A method for forming a blind via HDI printed circuit board based on laser and hot pressing

Abstract

The application discloses a kind of based on laser and hot-pressing integrated forming blind hole HDI printed circuit board method, the present application relates to the technical field of forming blind hole HDI printed circuit board, it includes the following steps: S1, take out an auxiliary positioning assembly;S2, the bar-shaped base of auxiliary positioning assembly is placed on the mesa of tooling table;S3, take out a second circuit board;S4, take out a solidification piece B;S5, each through hole B of second circuit board is respectively covered in each positioning cylinder outside of auxiliary positioning assembly;S6, each through hole b of solidification piece B is respectively covered in each positioning cylinder outside of auxiliary positioning assembly;S7, take out a first circuit board;S8, worker controls the hot-pressing head B of hot press machine and moves downward;S9, so that hot-pressing head B is away from first circuit board.The beneficial effects of the present application are: greatly improve the forming efficiency of blind hole HDI printed circuit board, greatly improve the forming quality of blind hole HDI printed circuit board.

Description

Technical Field

[0001] This invention relates to the technical field of forming HDI printed circuit boards with blind vias, and in particular to a method for forming HDI printed circuit boards with blind vias based on laser and thermoforming. Background Technology

[0002] HDI printed circuit boards are double-layer circuit boards, characterized by fast data transmission and low transmission loss. They are widely installed in chassis to control the normal operation of electrical equipment.

[0003] The structure of an HDI printed circuit board with blind via A produced by a certain workshop for a customer is as follows: Figures 1-2 As shown, it includes a first circuit board 1 and a second circuit board 2. A curing sheet A3 is fixed between the first circuit board 1 and the second circuit board 2 to fix the two circuit boards together. Multiple through holes A4 are opened in the horizontal direction of the inner side of the second circuit board 2. A blind hole A is formed between the inner wall of the through hole A4 and the top surface of the curing sheet A3. The blind hole A is used to install the customer's electronic components.

[0004] The method used by the workers in the workshop to form this type of HDI printed circuit board with blind vias is as follows:

[0005] S1. The worker takes out a first circuit board 1 and places it flat on the table of machine 5, as follows. Figure 3 As shown; then the worker places a curing sheet A3 flat on the top surface of the first circuit board 1, as shown. Figure 4 As shown, and ensure that the four outer end faces of the cured sheet A3 are flush with the four outer end faces of the first circuit board 1 respectively;

[0006] S2. A worker takes out a second circuit board 2 and drills multiple through holes A4 horizontally inside the second circuit board 2 using a drilling machine. After drilling, burrs 6 are distributed at the top and bottom ends of each through hole A4 on the second circuit board 2. Figure 5 As shown;

[0007] S3. Workers use grinding equipment to remove the burrs 6 at the top and bottom ports of each through hole A4 inside the second circuit board 2, such as... Figure 6 As shown;

[0008] S4. The worker places the second circuit board 2, after removing the burrs 6, flat on the top surface of the cured sheet A3, as follows: Figure 7 As shown, and ensure that the four outer end faces of the second circuit board 2 are flush with the four outer end faces of the curing sheet A3 respectively. At this time, the inner wall of the through hole A4 and the top surface of the curing sheet A3 form a blind hole A.

[0009] S5. The worker controls the hot press head A7 of the hot press to move downwards, so that the hot press head A7 presses against the top surface of the second circuit board 2, as shown. Figure 8 As shown, the heat on the hot press head A7 is transferred to the second circuit board 2, and the second circuit board 2 then transfers the heat to the curing sheet A3. After holding the pressure for a period of time, the curing sheet A3 after being heated and pressed will fix the first circuit board 1 and the second circuit board 2 together, thereby forming the first HDI printed circuit board with blind hole A.

[0010] S6. Control the hot press head A7 of the hot press to move upward so that the hot press head A7 is away from the second circuit board 2; then the worker removes the HDI printed circuit board with blind hole A.

[0011] S7. Workers can repeat steps S1 to S6 multiple times to form multiple HDI printed circuit boards with blind vias A.

[0012] However, although this molding method can produce HDI printed circuit boards with blind vias A, it still exhibits the following technical defects in actual operation:

[0013] I. In steps S2 to S3, after the drilling equipment drills multiple through holes A4 in the second circuit board 2 along its horizontal direction, it is necessary to use a grinding equipment to grind away the burrs 6 at the top and bottom ports of each through hole A4 in the second circuit board 2 before the produced second circuit board 2 can be put into use in subsequent processes. This undoubtedly increases the grinding process, thereby prolonging the forming time of the HDI printed circuit board with blind holes, and thus reducing the forming efficiency of the HDI printed circuit board with blind holes.

[0014] II. In step S5, after the hot press head A7 presses against the top surface of the second circuit board 2, a portion of the material of the cured sheet A3 after being heated and pressed will enter the through hole A4 of the second circuit board 2. The direction of entry of this portion of material is as follows: Figure 8 As shown by the middle arrow, and attached to the inner wall of the through hole A4, this means that some of the material of the cured sheet A3 after being heated and pressed will adhere to the inner wall of the blind hole [while the process requires that the inner wall of the blind hole should not have any excess material]. This undoubtedly reduces the molding quality of the HDI printed circuit board with blind holes.

[0015] Therefore, there is an urgent need for a molding method that can greatly improve the molding efficiency and molding quality of HDI printed circuit boards with blind vias. Summary of the Invention

[0016] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for molding HDI printed circuit boards with blind vias by integrating laser and hot pressing, which greatly improves the molding efficiency and molding quality of HDI printed circuit boards with blind vias.

[0017] The objective of this invention is achieved through the following technical solution: a method for molding a blind-via HDI printed circuit board based on laser and thermoforming, comprising the following steps:

[0018] S1. Take out an auxiliary positioning component, which includes a strip base. Multiple countersunk holes are opened on the top surface of the strip base along its horizontal direction. A vertical spring is fixed at the bottom of each countersunk hole. A positioning cylinder extending outside the countersunk hole is fixed to the top of each vertical spring. The positioning cylinder slides with the countersunk hole.

[0019] S2. The worker places the strip base of the auxiliary positioning component flat on the workbench table.

[0020] S3. The worker takes out a second circuit board and uses a laser cutting device to laser cut multiple through holes B in the second circuit board along its horizontal direction, and ensures that each through hole B corresponds to each positioning cylinder of the auxiliary positioning component. At the same time, the worker ensures that the diameter of the through hole B is equal to the diameter of the positioning cylinder.

[0021] S4. The worker takes out a curing sheet B and drills multiple through holes b in the curing sheet B along its horizontal direction using a drilling device. The worker ensures that each through hole b corresponds to a positioning cylinder of the auxiliary positioning component. At the same time, the worker ensures that the diameter of the through hole b is equal to the diameter of the positioning cylinder.

[0022] S5. The worker places each through hole B of the second circuit board onto the outside of each positioning cylinder of the auxiliary positioning component, and then supports the second circuit board on the top surface of the strip base.

[0023] S6. The worker places each through hole b of the curing sheet B onto the outside of each positioning cylinder of the auxiliary positioning component, and then supports the curing sheet B on the top surface of the second circuit board. At this time, the top surface of the curing sheet B is just flush with the top surface of the positioning cylinder.

[0024] S7. The worker takes out a first circuit board and places the first circuit board flat on the top surface of the curing sheet B, and ensures that the four outer end faces of the first circuit board are flush with the four outer end faces of the curing sheet B respectively. At this time, the bottom surface of the first circuit board, the inner wall of the through hole b of the curing sheet B, and the inner wall of the through hole B of the second circuit board form a blind hole B.

[0025] S8. The worker controls the hot press head B of the hot press to move downward, so that the hot press head B presses on the top surface of the first circuit board. The heat on the hot press head B is transferred to the first circuit board, and the first circuit board then transfers the heat to the curing sheet B. After holding the pressure for a period of time, the curing sheet B after being heated and pressed will fix the first circuit board and the second circuit board together, thereby forming the first HDI printed circuit board with blind hole B.

[0026] S9. Control the hot press head B of the hot press to move upward so that the hot press head B is away from the first circuit board; then the worker removes the HDI printed circuit board with blind hole B from the auxiliary positioning assembly.

[0027] S10. Workers can repeat steps S2 to S9 multiple times to form multiple HDI printed circuit boards with blind vias B.

[0028] In step S1, the spacing between any two adjacent countersunk holes is equal.

[0029] In step S1, the bottom end of the vertical spring is welded to the bottom of the countersunk hole, and the top end of the vertical spring is welded to the bottom surface of the positioning cylinder.

[0030] In step S3, the size of the second circuit board is smaller than the size of the strip base.

[0031] In step S4, the thickness of the cured sheet B is 0.5~0.8mm.

[0032] The present invention has the following advantages: it greatly improves the molding efficiency of HDI printed circuit boards with blind vias and greatly improves the molding quality of HDI printed circuit boards with blind vias. Attached Figure Description

[0033] Figure 1 A schematic diagram of the structure of an HDI printed circuit board with blind via A;

[0034] Figure 2 for Figure 1 MM section view;

[0035] Figure 3 This is a schematic diagram showing the first circuit board being placed flat on the machine tool.

[0036] Figure 4 A schematic diagram showing a cured sheet A placed flat on the top surface of a first circuit board;

[0037] Figure 5 This is a schematic diagram showing burrs distributed at the top and bottom ports of each through hole A on the second circuit board.

[0038] Figure 6 A schematic diagram for grinding away the burrs at the top and bottom ports of each through hole A in the second circuit board;

[0039] Figure 7 This is a schematic diagram showing the second circuit board placed flat on the top surface of the cured wafer A.

[0040] Figure 8 A schematic diagram showing how the hot press head A is pressed against the top surface of the second circuit board;

[0041] Figure 9A schematic diagram of the auxiliary positioning component;

[0042] Figure 10 A schematic diagram showing the strip base of the auxiliary positioning component placed flat on the tooling table.

[0043] Figure 11 This is a schematic diagram showing how multiple through holes B are laser-cut along the horizontal direction within a second circuit board using a laser cutting device.

[0044] Figure 12 A schematic diagram showing multiple through holes b drilled horizontally within the cured sheet B using a drilling device.

[0045] Figure 13 This is a schematic diagram showing how each through hole B of the second circuit board is fitted onto the outside of each positioning cylinder of the auxiliary positioning assembly.

[0046] Figure 14 This is a schematic diagram showing how each through hole b of the cured sheet B is fitted onto the outside of each positioning cylinder of the auxiliary positioning assembly.

[0047] Figure 15 This is a schematic diagram showing the first circuit board placed flat on the top surface of the cured wafer B.

[0048] Figure 16 for Figure 15 A magnified view of part I;

[0049] Figure 17 A schematic diagram showing how the hot press head B is pressed against the top surface of the first circuit board.

[0050] Figure 18 A schematic diagram of an HDI printed circuit board with blind via B;

[0051] In the picture:

[0052] 1-First circuit board, 2-Second circuit board, 3-Curved sheet A, 4-Through hole A, 5-Machine base, 6-Burry, 7-Hot press head A;

[0053] 8-Strip base, 9-Counterhead hole, 10-Vertical spring, 11-Positioning cylinder, 12-Tooling table, 13-Through hole B, 14-Curing sheet B, 15-Through hole b, 16-Hot press head B. Detailed Implementation

[0054] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description:

[0055] A method for molding a blind via HDI printed circuit board based on laser and thermoforming, comprising the following steps:

[0056] S1, Take out one such as Figure 9 The auxiliary positioning component shown includes a strip-shaped base 8. Multiple countersunk holes 9 are formed on the top surface of the strip-shaped base 8 along its horizontal direction. The spacing between any two adjacent countersunk holes 9 is equal. A vertical spring 10 is fixed to the bottom of each countersunk hole 9. A positioning cylinder 11 extending outside the countersunk hole 9 is fixed to the top of each vertical spring 10. The positioning cylinder 11 slides in conjunction with the countersunk hole 9. The bottom end of the vertical spring 10 is welded to the bottom of the countersunk hole 9, and the top end of the vertical spring 10 is welded to the bottom surface of the positioning cylinder 11.

[0057] S2. The worker places the strip base 8 of the auxiliary positioning component flat on the table surface of the tooling table 12, such as... Figure 10 As shown;

[0058] S3. The worker takes out a second circuit board 2 and uses a laser cutting device to laser-cut multiple through holes B13 along its horizontal direction inside the second circuit board 2, such as... Figure 11 As shown, and ensure that each through hole B13 corresponds to each positioning cylinder 11 of the auxiliary positioning component, and at the same time ensure that the diameter of the through hole B13 is equal to the diameter of the positioning cylinder 11; the size of the second circuit board 2 is smaller than the size of the strip base 8.

[0059] In step S3, because the laser cutting equipment uses a laser beam to cut the second circuit board 2, the cutting precision is high. Therefore, after the laser cutting equipment drills multiple through holes B13 in the horizontal direction of the second circuit board 2, there are no burrs at the top and bottom ends of the through holes B13. Compared with the process in the workshop, this is much smoother. Figures 1-8 The forming method shown eliminates the need for subsequent grinding of burrs using grinding equipment, thus saving the grinding process. This allows the processed second circuit board 2 to be quickly put into use in subsequent processes, thereby shortening the forming time of HDI printed circuit boards with blind vias and greatly improving the forming efficiency of HDI printed circuit boards with blind vias.

[0060] S4. The worker removes a cured sheet B14, which is 0.5~0.8mm thick. Multiple through holes b15 are drilled horizontally inside the cured sheet B14 using a drilling machine. Figure 12 As shown, ensure that each through hole b15 corresponds to each positioning cylinder 11 of the auxiliary positioning assembly, and at the same time, ensure that the diameter of the through hole b15 is equal to the diameter of the positioning cylinder 11.

[0061] S5. The worker places each through hole B13 of the second circuit board 2 onto the outside of each positioning cylinder 11 of the auxiliary positioning assembly, such as... Figure 13 As shown, the second circuit board 2 is then supported on the top surface of the strip base 8;

[0062] S6. The worker places the through holes b15 of the cured sheet B14 onto the outside of each positioning cylinder 11 of the auxiliary positioning assembly, such as... Figure 14 As shown, the curing sheet B14 is then supported on the top surface of the second circuit board 2. At this time, the top surface of the curing sheet B14 is just flush with the top surface of the positioning cylinder 11.

[0063] S7. The worker takes out a first circuit board 1 and places it flat on the top surface of the cured wafer B14, as shown. Figures 15-16 As shown, and ensure that the four outer end faces of the first circuit board 1 are flush with the four outer end faces of the curing sheet B14 respectively, at this time, the bottom surface of the first circuit board 1, the inner wall of the through hole b15 of the curing sheet B14, and the inner wall of the through hole B13 of the second circuit board 2 form a blind hole B.

[0064] S8. The worker controls the hot press head B16 of the hot press to move downwards, so that the hot press head B16 presses against the top surface of the first circuit board 1, as shown. Figure 17 As shown, heat from the hot press head B16 is transferred to the first circuit board 1, which in turn transfers heat to the curing sheet B14. After holding the pressure for a period of time, the heat-pressed curing sheet B14 bonds the first circuit board 1 and the second circuit board 2 together, thus forming the first HDI printed circuit board with blind via B. The structure of the HDI printed circuit board with blind via B is as follows: Figure 18 As shown;

[0065] In steps S5 to S8, since each through hole B13 of the second circuit board 2 is fitted onto the outside of each positioning cylinder 11, and since each through hole b15 of the cured sheet B14 is fitted onto the outside of each positioning cylinder 11, the positioning cylinder 11 supports both the through holes B13 and the through holes b15.

[0066] Therefore, when the hot press head B16 presses against the top surface of the first circuit board 1, a portion of the material of the cured sheet B14 after hot pressing will not enter the through hole B13 of the second circuit board 2. In other words, a portion of the material of the cured sheet B14 after hot pressing will not adhere to the inner wall of the blind hole. Thus, this method, compared to methods used in workshops, [is more efficient / effective]. Figures 1-8 The molding method shown meets the process requirements, thereby greatly improving the molding quality of HDI printed circuit boards with blind vias.

[0067] S9. Control the hot press head B16 of the hot press to move upward so that the hot press head B16 is away from the first circuit board 1; then the worker removes the HDI printed circuit board with blind hole B from the auxiliary positioning assembly.

[0068] S10. Workers can repeat steps S2 to S9 multiple times to form multiple HDI printed circuit boards with blind vias B.

Claims

1. A method for forming a blind-via HDI printed circuit board based on laser and hot pressing, characterized in that: It includes the following steps: S1, take out an auxiliary positioning assembly, the auxiliary positioning assembly includes a strip-shaped base (8), a plurality of countersunk holes (9) are opened on the top surface of the strip-shaped base (8) and along the horizontal direction thereof, a vertical spring (10) is fixedly arranged at the bottom of each countersunk hole (9), and a positioning cylinder (11) extending outside the countersunk hole (9) is fixedly connected to the top end portion of each vertical spring (10), and the positioning cylinder (11) is in sliding fit with the countersunk hole (9); S2, the worker places the strip-shaped base (8) of the auxiliary positioning assembly on the table surface of the tooling table (12); S3, the worker takes out a second circuit board (2), cuts a plurality of through holes B (13) in the second circuit board (2) along the horizontal direction thereof through a laser cutting device, and ensures that each through hole B (13) corresponds to each positioning cylinder (11) of the auxiliary positioning assembly respectively, and at the same time, ensures that the diameter of the through hole B (13) is equal to the diameter of the positioning cylinder (11); S4, the worker takes out a solidification sheet B (14), drills a plurality of through holes b (15) in the solidification sheet B (14) along the horizontal direction thereof through a drilling device, and ensures that each through hole b (15) corresponds to each positioning cylinder (11) of the auxiliary positioning assembly respectively, and at the same time, ensures that the diameter of the through hole b (15) is equal to the diameter of the positioning cylinder (11); S5, the worker respectively sleeves each through hole B (13) of the second circuit board (2) outside each positioning cylinder (11) of the auxiliary positioning assembly, and then supports the second circuit board (2) on the top surface of the strip-shaped base (8); S6, the worker respectively sleeves each through hole b (15) of the solidification sheet B (14) outside each positioning cylinder (11) of the auxiliary positioning assembly, and then supports the solidification sheet B (14) on the top surface of the second circuit board (2), at this time, the top surface of the solidification sheet B (14) is flush with the top surface of the positioning cylinder (11); S7, the worker takes out a first circuit board (1), places the first circuit board (1) on the top surface of the solidification sheet B (14), and ensures that the four outer end surfaces of the first circuit board (1) are flush with the four outer end surfaces of the solidification sheet B (14), at this time, a blind hole B is formed between the bottom surface of the first circuit board (1), the inner wall of the through hole b (15) of the solidification sheet B (14) and the inner wall of the through hole B (13) of the second circuit board (2); S8, the worker controls the hot pressing head B (16) of the hot press to move downward, so that the hot pressing head B (16) is pressed on the top surface of the first circuit board (1), the heat on the hot pressing head B (16) is transmitted to the first circuit board (1), and the first circuit board (1) transmits the heat to the solidification sheet B (14), after a certain pressure maintaining time, the solidification sheet B (14) after heat pressing fixes the first circuit board (1) and the second circuit board (2) together, thereby forming a first HDI printed circuit board with a blind hole B; S9. The hot press head B (16) of the hot press is controlled to move upward so that the hot press head B (16) is away from the first circuit board (1); then the worker takes the HDI printed circuit board with the blind hole B from the auxiliary positioning assembly; S10. The worker repeats the operations of steps S2-S9 for multiple times, so that multiple HDI printed circuit boards with blind holes B are formed.

2. The method of claim 1, wherein the method is a method of forming a laser and hot-pressing based HDI printed circuit board with blind vias. In the step S1, the distance between every two adjacent counter sunk holes (9) is equal.

3. The method of claim 1, wherein the method is characterized by: In the step S1, the bottom end of the vertical spring (10) is welded to the bottom of the counter sunk hole (9), and the top end of the vertical spring (10) is welded to the bottom surface of the positioning cylinder (11).

4. The method of claim 1, wherein the method is characterized by: In the step S3, the size of the second circuit board (2) is smaller than the size of the strip-shaped base (8).

5. The method of claim 1, wherein the method is characterized by: In the step S4, the thickness of the curing sheet B (14) is 0.5-0.8 mm.

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