Multi-layer PCB manufacturing method and PCB

Abstract

The invention discloses a multi-layer PCB manufacturing method and a PCB, and the manufacturing method comprises the steps: S1, sequentially arranging a second sheet and a third sheet above a first sheet, arranging first prepregs between the first sheet and the second sheet and between the second sheet and the third sheet, and taking the second sheet as a symmetric center, the first sheet, the second sheet and the third sheet are subjected to hot pressing, and the first sheet, the second sheet and the third sheet form a symmetrical part after being subjected to hot pressing; s2, a fourth sheet is arranged on one side of the symmetrical part, a symmetrical sheet is arranged on the other side of the symmetrical part, a second prepreg is arranged between the fourth sheet and the symmetrical part, a second prepreg is arranged between the symmetrical sheet and the symmetrical part, and the fourth sheet, the symmetrical part and the symmetrical sheet are subjected to hot pressing to form a symmetrical laminated structure; and S3, symmetrical sheets in the symmetrical laminated structure are separated, and the remaining sheets are finished product boards. According to the invention, the warping degree of the finished PCB can be reduced, and the reject ratio of PCB production is reduced.

Description

Technical Field

[0001] This invention relates to the field of PCB manufacturing technology, and in particular to a method for manufacturing a multilayer PCB and the PCB itself. Background Technology

[0002] When manufacturing PCBs with four or more layers of asymmetric stacked structure, the PCBs need to be subjected to multiple high-temperature pressing processes. During pressing, the shrinkage of the prepreg can cause the PCB to warp and deform to one side. When the PCB warps severely, it can easily cause equipment jamming and damage during the manufacturing process, seriously affecting normal production. Therefore, there is an urgent need for a manufacturing method that can reduce the warping phenomenon in the production of asymmetric stacked PCBs. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing a multilayer PCB board and a PCB board, so as to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0004] The solution to the technical problem of this invention is: In a first aspect, this application provides a method for manufacturing a multilayer PCB board, comprising: S1: A second sheet and a third sheet are sequentially arranged above a first sheet. A first semi-cured sheet is arranged between the first sheet and the second sheet, and between the second sheet and the third sheet. The first sheet, the second sheet and the third sheet are hot-pressed with the second sheet as the center of symmetry. The first sheet, the second sheet and the third sheet are formed into a symmetrical part after hot pressing. S2: A fourth sheet is provided on one side of the symmetrical part and a symmetrical sheet is provided on the other side. A second semi-cured sheet is provided between the fourth sheet and the symmetrical part. A second semi-cured sheet is provided between the symmetrical sheet and the symmetrical part. The fourth sheet, the symmetrical part and the symmetrical sheet are hot-pressed to form a symmetrical laminated structure. S3: Separate the symmetrical sheets in the symmetrical laminated structure, and the remaining part is the finished board.

[0005] The technical solution has at least the following beneficial effects: In S1, when the first sheet, the second sheet and the third sheet are hot-pressed, the first semi-cured sheet between the first sheet and the second sheet is deformed by heat, and the first semi-cured sheet between the second sheet and the third sheet is deformed by heat. While the first sheet, the second sheet and the third sheet are bonded and fixed, the two first semi-cured sheets deform symmetrically with the second sheet as the center of symmetry. The two first semi-cured sheets generate bending moments of similar magnitude and opposite direction. The two bending moments cancel each other out, thereby greatly reducing the resultant moment on the entire symmetrical part itself, and thus reducing the degree of warping of the symmetrical part under the action of the resultant moment. Meanwhile, the required second semi-cured sheet and fourth sheet are further superimposed on the symmetrical part, and the second semi-cured sheet and symmetrical sheet are placed on the other side of the symmetrical part away from the fourth sheet. During hot pressing, the second semi-cured sheets on both sides also generate torques of similar magnitude but opposite direction. The two cancel each other out, greatly reducing the resultant torque on the finished board formed by the combination of the symmetrical part and the fourth sheet, thereby reducing the degree of warping of the finished board. In addition, the PCB board in this application needs to be laminated multiple times. Even if there is warping after the first lamination, if it is not controlled, a new unbalanced torque will be added when the sheets are stacked again for hot pressing. Therefore, by setting symmetrical sheets, it is equivalent to re-establishing a symmetrical environment each time hot pressing, so that the warping of the finished board after each lamination can be effectively controlled. In this way, the accumulation of warping can be effectively reduced and the yield of the finished board can be improved.

[0006] As a further improvement to the above technical solution, the method of S2 further includes: sequentially setting the second semi-cured sheet and the fourth sheet on one side of the symmetrical portion, sequentially setting the second semi-cured sheet and the symmetrical sheet on the other side of the symmetrical portion, and performing hot pressing, repeating the above actions until a symmetrical stacked structure with a predetermined number of layers is obtained.

[0007] As a further improvement to the above technical solution, the number of the first semi-cured sheets between the first sheet and the second sheet, and the number of the first semi-cured sheets between the second sheet and the third sheet, are equal, and their thicknesses are the same.

[0008] As a further improvement to the above technical solution, the number of second semi-cured sheets between the fourth sheet and the symmetrical portion, and the number of second semi-cured sheets between the symmetrical portion and the fourth sheet, are equal, and their thicknesses are the same.

[0009] As a further improvement to the above technical solution, a resist film is provided between the first sheet and the symmetrical sheet.

[0010] As a further improvement to the above technical solution, the specific method of S2 includes: setting a third semi-cured sheet between the second semi-cured sheet and the first sheet, opening an installation channel on the third semi-cured sheet, installing the resist film in the installation channel, with one side of the resist film abutting against the first sheet and the other side abutting against the symmetrical sheet.

[0011] As a further improvement to the above technical solution, the method between S3 and S4 further includes: screwing the symmetrical stacked structure, wherein the projection of the screwing path on the horizontal plane is located within the projection of the adhesive resist film on the same plane.

[0012] As a further improvement to the above technical solution, in S1, the first sheet, the second sheet and the third sheet are hot-pressed from the top and bottom sides; In S2, the fourth sheet, the symmetrical portion, and the symmetrical sheet are hot-pressed from the top and bottom sides.

[0013] As a further improvement to the above technical solution, in S1, laser blind holes, blind hole copper filling, and patterned circuit etching can be performed between the first sheet and the second sheet and / or between the third sheet and the second sheet.

[0014] Secondly, this application provides a PCB board manufactured using a multilayer PCB board manufacturing method as described in the first aspect. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly explained below. Obviously, the described drawings are only a part of the embodiments of the present invention, and not all of them. Those skilled in the art can obtain other design schemes and drawings based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the symmetrical part in this invention; Figure 2 This is a schematic diagram of the structure of the present invention when a fourth sheet and a symmetrical sheet are superimposed on the symmetrical part; Figure 3 This is a schematic diagram of the structure of the present invention when multiple fourth sheets and multiple symmetrical sheets are superimposed on the symmetrical part; Figure 4 This is a schematic diagram of the structure when the symmetrical layered structure is grooved in this invention; Figure 5 This is a schematic diagram of the structure when the finished board is separated from multiple symmetrical sheets. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0019] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] During the manufacturing process of PCB boards, the prepreg in the board often shrinks due to heat during high-temperature lamination, causing the entire board to warp and deform towards the prepreg. When manufacturing asymmetrical stacked PCB boards with multi-layer structures, multiple laminations are required on the same side of the PCB board to stack the new prepreg and copper foil onto the original board. Each lamination increases the thickness of the PCB board, and the warpage of the PCB board also increases, which may prevent the PCB board from completing subsequent processes. Therefore, this application provides a manufacturing method that can reduce the warpage of multi-layer PCB boards.

[0022] Example 1 This application provides a method for manufacturing a multilayer PCB board, which includes: S1: Reference Figure 1A second sheet 120 and a third sheet 130 are sequentially arranged above the first sheet 110. A first semi-cured sheet 140 is arranged between the first sheet 110 and the second sheet 120, and between the second sheet 120 and the third sheet 130. The first sheet 110, the second sheet 120 and the third sheet 130 are hot-pressed with the second sheet 120 as the center of symmetry. The first sheet 110, the second sheet 120 and the third sheet 130 are hot-pressed to form a symmetrical part 100. S2: Reference Figures 2 to 4 A fourth sheet 200 is provided on one side of the symmetrical portion 100 and a symmetrical sheet 300 is provided on the other side. A second semi-cured sheet 400 is provided between the fourth sheet 200 and the symmetrical portion 100, and a second semi-cured sheet 400 is provided between the symmetrical sheet 300 and the symmetrical portion 100. The fourth sheet 200, the symmetrical portion 100 and the symmetrical sheet 300 are hot-pressed to form a symmetrical laminated structure. S3: Reference Figure 5 The symmetrical sheet 300 in the symmetrical laminated structure is separated, and the remaining part is the finished board.

[0023] In this embodiment, both the first sheet 110 and the second sheet 120 include interconnected core plates and electroplated layers.

[0024] As can be seen from the above, in S1, when the first sheet 110, the second sheet 120 and the third sheet 130 are hot-pressed, the first semi-cured sheet 140 between the first sheet 110 and the second sheet 120 is deformed by heat, and the first semi-cured sheet 140 between the second sheet 120 and the third sheet 130 is deformed by heat. While the first sheet 110, the second sheet 120 and the third sheet 130 are bonded and fixed, the two first semi-cured sheets 140 deform symmetrically with the second sheet 120 as the center of symmetry. The two first semi-cured sheets 140 generate bending moments of similar magnitude and opposite direction. The two bending moments cancel each other out, thereby greatly reducing the resultant moment on the entire symmetrical part 100 itself, and thus reducing the degree of warping of the symmetrical part 100 under the action of the resultant moment. Simultaneously, the required second semi-cured sheet 400 and fourth sheet 200 are further superimposed on the symmetrical portion 100, and the second semi-cured sheet 400 and symmetrical sheet 300 are placed on the other side of the symmetrical portion 100 away from the fourth sheet 200. During hot pressing, with the symmetrical portion 100 as the second center of symmetry, the second semi-cured sheets 400 on both sides generate torques of similar magnitude but opposite directions. The two torques cancel each other out, greatly reducing the resultant torque on the finished board formed by the combination of the symmetrical portion 100 and the fourth sheet 200, thereby reducing the cost. The degree of warping of the board is such that, when manufacturing a PCB board including four layers of copper foil, the second sheet 120 in the middle is used as the center of symmetry to stack the symmetrical part 100, and then an additional symmetrical sheet 300 is added to achieve the stacking of the fourth sheet 200. That is, when stacking a four-layer PCB board, only one additional symmetrical sheet is needed, without having to use the first sheet 110 as the center of symmetry and add the second sheet 120, the third sheet 130 and the two corresponding symmetrical sheets 300 in sequence, thus reducing the consumption of raw materials; In addition, the PCB board in this application needs to be laminated multiple times. Even if there is warping after the first lamination, if it is not controlled, a new unbalanced torque will be added when the sheets are stacked again for hot pressing. Therefore, by setting symmetrical sheets 300, it is equivalent to re-establishing a symmetrical environment each time hot pressing, so that the warping of the finished board after each lamination can be effectively controlled. In this way, the accumulation of warping can be effectively reduced and the yield of the finished board can be improved.

[0025] Furthermore, in this application, because the production is assisted by the addition of symmetrical sheets 300 and a second prepreg, the finished PCB board can have its first sheet 110, second sheet 120, third sheet 130, fourth sheet 200, first prepreg 140, and second prepreg 400 customized according to requirements to fit the size of the customer's equipment without the need for changes in size and quantity, thus better meeting the customer's needs.

[0026] In S1, the specific method for "sequentially arranging the second sheet 120 and the third sheet 130 above the first sheet 110" includes: A metal module slot is formed on the first semi-cured sheet 140 between the first sheet 110 and the second sheet 120. The metal module is placed in the first semi-cured sheet 140 and connected to the first sheet 110 and the second sheet 120. Then, the first semi-cured sheet 140 and the third sheet 130 are placed on the second sheet 120 in sequence. In this way, each component can be processed separately before connecting the first sheet 110, the second sheet 120 and the third sheet 130.

[0027] In S1, the first sheet 110, the second sheet 120 and the third sheet 130 are hot-pressed from the top and bottom sides. By hot-pressing the top and bottom sides simultaneously, the first semi-cured sheet 140 on the top and bottom sides is heated to a similar degree, which makes their deformation and shrinkage similar. The resulting bending moments are closer, which reduces the magnitude of the resultant moment after mutual cancellation, and further reduces warping.

[0028] In S1, after the hot pressing of the symmetrical part 100 is completed, the specific manufacturing method also includes opening blind holes, filling copper in blind holes and etching pattern routes between the first sheet 110 and the second sheet 120 and / or between the third sheet 130 and the second sheet 120. Through this scheme, it is easy to open preset blind holes between the layers of the PCB board. As long as the hot pressing and stacking are completed, the blind holes can be opened smoothly in the PCB board.

[0029] In some embodiments, as shown in the figure, taking a six-layer PCB board as an example, step S2 includes the following steps: S21: A second pre-cured sheet 400 and a first fourth sheet 200 are placed sequentially above the symmetrical portion 100, and a second pre-cured sheet 400 and a first symmetrical sheet 300 are arranged sequentially below the symmetrical portion 100. S22: A second pre-cured sheet 400 and a second fourth sheet 200 are sequentially arranged above the first fourth sheet 200, and a second pre-cured sheet 400 and a second symmetrical sheet 300 are sequentially placed below the first symmetrical sheet 300. S23: Hot-press the symmetrical portion 100, the fourth sheet 200, and the symmetrical sheet 300 obtained in S21 or S22; S24: Repeat the operation of stacking the fourth sheet 200 in S22 and the hot pressing operation in S23 until a six-layer PCB board is obtained.

[0030] As can be seen from the above, when manufacturing a six-layer PCB board, by stacking multiple fourth sheets 200 on the upper side of the symmetrical part 100 and multiple symmetrical sheets 300 on the lower side of the symmetrical part 100, during each hot pressing process, the second semi-cured sheets 400 on the upper and lower sides of the symmetrical part 100 generate torques of opposite directions and similar magnitudes after being heated and contracted. After the two torques on the upper and lower sides of the symmetrical part 100 cancel each other out, the resultant torque on the symmetrical stacked structure is greatly reduced, thereby reducing the degree of bending of each part of the symmetrical stacked structure.

[0031] In S23 and S24, the fourth sheet 200, the symmetrical part 100 and the symmetrical sheet 300 are hot-pressed from the top and bottom sides. By hot-pressing the top and bottom sides simultaneously, the second semi-cured sheet 400 on the top and bottom sides are heated to a similar degree, so that their deformation and shrinkage are similar and the bending moments generated are closer. This reduces the magnitude of the resultant moment after they cancel each other out, and further reduces warping.

[0032] As a further embodiment of the above embodiments, the number of first semi-cured sheets 140 between the first sheet 110 and the second sheet 120 and between the second sheet 120 and the third sheet 130 are equal and have the same thickness; the number of second semi-cured sheets 400 between the fourth sheet 200 and the symmetrical portion 100 and between the symmetrical portion 100 and the fourth sheet 200 are equal and have the same thickness.

[0033] By controlling the specifications of the first prepreg 140 and the second prepreg 400 and their quantities at various locations, the torques generated between the first prepreg 140 and the second prepreg 400 with the symmetry part 100 as the center of symmetry are made numerically closer, thereby reducing PCB warpage better after they cancel each other out.

[0034] Reference Figure 3 A resist film 500 is disposed between the first sheet 110 and the symmetrical sheet 300. The specific method of s2 includes: disposing of a third semi-cured sheet 600 between the second semi-cured sheet 400 and the first sheet 110; creating an installation channel on the third semi-cured sheet 600; and installing the resist film 500 in the installation channel, with one side of the resist film 500 abutting against the first sheet 110 and the other side abutting against the symmetrical sheet 300. The method between S2 and S3 includes: spruing the symmetrical laminated structure, wherein the projection of the sprue cutting path on the horizontal plane is located within the projection of the resist film 500 on the same plane.

[0035] By adopting the above technical solution, because the second semi-cured sheet 400 does not contact the first sheet 110 at this location under the action of the resist film 500, after hot pressing, the second semi-cured sheet 400 will only be connected to the side of the resist film 500 away from the first sheet 110, while the third semi-cured sheet 600 will be connected to the first sheet 110 after being heated, thereby maintaining the connection between the second semi-cured sheet 400 and the first sheet 110. When the board is being rolled, the portion of the third semi-cured sheet 600 outside the resist film 500 is cut off. At this time, only the resist film 500 is set between the first sheet 110 and the second semi-cured sheet 400. The finished board can be directly removed to achieve its separation from multiple symmetrical sheets 300, reducing the difficulty of separation.

[0036] Furthermore, after the s3 process, once a finished board with a predetermined number of layers is obtained, perforations can be made from the outermost fourth sheet 200 or the first sheet 110 of the finished board, thereby creating through holes or buried holes on the finished board, and then copper filling is performed on the through holes or buried holes.

[0037] Secondly, this application provides a PCB board manufactured using a multilayer PCB board manufacturing method as described in the first aspect. The PCB board produced by this method can solve the long-standing defect in the PCB industry caused by severe warping of the board due to asymmetrical stacking, making it unsuitable for continued production.

[0038] Example 2 The difference between this embodiment and Embodiment 1 is that multiple fourth sheets 200 can be provided on both the upper and lower sides of the symmetrical portion 100. The number of fourth sheets 200 on one side of the symmetrical portion 100 is less than the number of fourth sheets 200 on the other side of the symmetrical portion 100, and the difference in number is 1. Specifically, in S2: S21: First, a second curing sheet and a fourth sheet 200 are sequentially set on both sides of the symmetrical part 100 and hot-pressed. Then, the patterns and lines of the fourth sheet 200 on both sides are etched. S22: Repeat S21 until a symmetrical stacked structure with one less layer than the preset number of layers is obtained on both sides of the symmetrical part 100. S23: On one side of the symmetrical stacked structure obtained in S22, a second prepreg 400 and a fourth sheet 200 are sequentially arranged, and on the other side, a third prepreg 600 with a resist film 500, a second prepreg 400 and a symmetrical sheet 300 are sequentially arranged, and hot pressing is performed to obtain a symmetrical stacked structure with an even number of fourth sheets 200, and patterns and lines are etched on the fourth sheet 200.

[0039] The symmetrical laminated structure after S23 is routerd, and the projection of the router's cutting path in the horizontal plane lies within the projection of the resist film 500 on the same plane. In this way, after routerting, the second prepreg 400 and the first sheet 110 at the resist film 500 are not bonded to each other. Separation of the symmetrical sheet 300 from the finished PCB board can be achieved simply by manually removing the symmetrical sheet 300 using automated tools.

[0040] By using the above scheme, when manufacturing multilayer PCBs, the fourth sheet 200 is stacked on both sides simultaneously. First, this method can reduce the warping of the PCB through a symmetrical structure. Second, by adding two sheets that do not need to be removed on the symmetrical part 100, the time for stacking the sheets is reduced, and the production speed of the PCB is increased.

[0041] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for manufacturing a multilayer PCB board, characterized in that, include: S1: A second sheet (120) and a third sheet (130) are sequentially arranged above the first sheet (110). A first semi-cured sheet (140) is arranged between the first sheet (110) and the second sheet (120) and between the second sheet (120) and the third sheet (130). The first sheet (110), the second sheet (120) and the third sheet (130) are hot-pressed with the second sheet (120) as the center of symmetry. The first sheet (110), the second sheet (120) and the third sheet (130) are hot-pressed to form a symmetrical part (100). S2: A fourth sheet (200) is provided on one side of the symmetrical portion (100), and a symmetrical sheet (300) is provided on the other side. A second semi-cured sheet (400) is provided between the fourth sheet (200) and the symmetrical portion (100), and a second semi-cured sheet (400) is provided between the symmetrical sheet (300) and the symmetrical portion (100). The fourth sheet (200), the symmetrical portion (100), and the symmetrical sheet (300) are hot-pressed to form a symmetrical laminated structure. S3: Separate the symmetrical sheet (300) in the symmetrical stacked structure, and the remaining part is the finished board.

2. The method for manufacturing a multilayer PCB board according to claim 1, characterized in that, The method of S2 further includes: sequentially setting the second semi-cured sheet (400) and the fourth sheet (200) on one side of the symmetrical portion (100), sequentially setting the second semi-cured sheet (400) and the symmetrical sheet (300) on the other side of the symmetrical portion (100), and performing hot pressing, repeating the above actions until a symmetrical stacked structure with a predetermined number of layers is obtained.

3. The method for manufacturing a multilayer PCB board according to claim 1, characterized in that, The number of the first semi-cured sheets (140) between the first sheet (110) and the second sheet (120) and between the second sheet (120) and the third sheet (130) are equal, and the thickness is the same.

4. The method for manufacturing a multilayer PCB board according to claim 1, characterized in that, The number and thickness of the second semi-cured sheet (400) between the fourth sheet (200) and the symmetrical portion (100) are equal.

5. A method for manufacturing a multilayer PCB board according to claim 1, characterized in that, A resist film (500) is disposed between the first sheet (110) and the symmetrical sheet (300).

6. A method for manufacturing a multilayer PCB board according to claim 5, characterized in that, The specific method of S2 includes: setting a third semi-cured sheet (600) between the second semi-cured sheet (400) and the first sheet (110), opening an installation channel on the third semi-cured sheet (600), installing the adhesive resist film (500) in the installation channel, with one side of the adhesive resist film (500) abutting against the first sheet (110) and the other side abutting against the symmetrical sheet (300).

7. A method for manufacturing a multilayer PCB board according to claim 5, characterized in that, The method between S2 and S3 further includes: screwing the symmetrical laminated structure, wherein the projection of the screwing path on the horizontal plane is located within the projection of the adhesive resist film (500) on the same plane.

8. A method for manufacturing a multilayer PCB board according to claim 1, characterized in that, In S1, the first sheet (110), the second sheet (120), and the third sheet (130) are hot-pressed from the top and bottom sides; In S2, the fourth sheet (200), the symmetrical portion (100), and the symmetrical sheet (300) are hot-pressed from the top and bottom sides.

9. A method for manufacturing a multilayer PCB board according to claim 1, characterized in that, In S1, laser blind vias, blind via copper filling, and patterned circuit etching can be performed between the first sheet (110) and the second sheet (120) and / or between the third sheet (130) and the second sheet (120).

10. A PCB board, characterized in that, The PCB board is manufactured using a multilayer PCB board manufacturing method as described in any one of claims 1-9.

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