Production method of printed circuit board with ball grid array

Abstract

The invention provides a production method of a printed circuit board with a ball grid array, which comprises the following steps of: finishing board grinding of resin plug holes on the printed circuit board, removing resin protruding out of a board surface and copper bulges around the holes, and drilling other holes except the resin plug holes; electroplating of hole copper and surface copper on the printed circuit board is carried out, and etching of the ball grid array position of the first surface is completed in an image transfer mode; according to the production method of the printed circuit board with the ball grid array, through image transfer, the position of the ball grid array is electroplated, then electrogilding is conducted, copper thickness increasing and electrogilding are conducted on the position of the ball grid array, and after the position of the ball grid array is covered with a dry film, pattern manufacturing of other positions of the printed circuit board is completed. According to the printed circuit board, the patterns at other positions are etched, so that the copper thickness at the position of the ball grid array can be independently electroplated to be higher and protrude out of other positions on the printed circuit board, and the smoothness and the fitting degree of the printed circuit board in the assembly process are improved.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to a method for producing printed circuit boards with ball grid arrays. Background Technology

[0002] With the advent of the AI ​​era, the requirements for product computing speed and power consumption are increasing, leading to more demanding chip requirements and consequently, larger chip designs. To ensure a perfect fit between the circuit board and the chip during assembly, special requirements are placed on the BGA (Ball Grid Array) within the circuit board: the BGA area needs to be gold-plated, conductive traces are not allowed, and the BGA area needs to be higher than the surrounding areas to ensure smooth assembly and a perfect fit.

[0003] If traditional circuit board manufacturing methods are used, the BGA is positioned lower than other surrounding areas. Furthermore, existing processes have limitations when performing gold plating on BGAs, primarily in the following two aspects: 1. Due to the limitations of circuit board design, the traditional process for BGA gold plating has many constraints and relatively few usable processes, which cannot meet the requirements. 2. The pattern of the BGA is etched together with the outer layer circuitry. Due to the design of the inner layer pattern and the BGA itself, the position of the BGA will be lower than other positions after the board is laminated. In addition, during electroplating, because the BGA position is a low current area, the copper plating thickness will also be lower than other positions. All in all, the position of the BGA will be lower than other positions. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for manufacturing printed circuit boards with ball grid arrays to address at least one of the problems mentioned above.

[0005] The present invention provides a method for manufacturing printed circuit boards with ball grid arrays, comprising the following steps: A grinding plate is used to complete the resin-filled holes on a printed circuit board. The resin protruding from the board surface and the copper bumps around the holes are removed, and the remaining holes except for the resin-filled holes are drilled. Electroplating of the hole copper and surface copper on the printed circuit board is performed, and etching of the ball grid array position on the first side is completed by image transfer. The copper thickness of the ball grid array position is increased and gold is electroplated. After the ball grid array position is covered with dry film, the pattern fabrication of other positions of the printed circuit board is completed.

[0006] In one embodiment, prior to the step of grinding the plate to complete the resin-filled vias on the printed circuit board, the method further includes: The substrate is obtained by multiple laminations, and preliminary drilling is completed on the substrate. Back drilling is added to the holes that need to be filled by electroplating. Then, copper plating of the holes is performed through image transfer; Complete the resin plugging process.

[0007] In one embodiment, the steps of thickening the copper and electroplating gold at the ball grid array location include: The positions of the ball grid array are exposed by using a film, while other positions are covered and protected with dry film before electroplating.

[0008] In one embodiment, the steps of thickening the copper and electroplating gold at the ball grid array location include: The positions of the ball grid array are developed using a film, and other positions are protected with a dry film. Then, gold is electroplated at the positions of the ball grid array.

[0009] The technical solutions provided in the embodiments of the present invention bring the following beneficial technical effects:

[0010] The method for producing a printed circuit board with a ball grid array provided by the present invention uses image transfer to electroplate the positions of the ball grid array, then electroplate gold, and then etch patterns in other positions. This method can electroplate the copper thickness of the ball grid array positions higher, making them protrude from other positions on the printed circuit board, thereby improving the smoothness and fit of the printed circuit board during assembly.

[0011] Additional aspects and advantages of this application will be set forth in the following sections and will be understood in detail from the following description, or may be learned by specific practice of the invention. Attached Figure Description

[0012] Figure 1 This is a schematic flowchart of a method for manufacturing a printed circuit board with a ball grid array according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the preceding method flow of S100 in one embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the structural changes of a printed circuit board with a ball grid array in one embodiment of the present invention. Detailed Implementation

[0013] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Possible embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein with reference to the drawings. The embodiments described with reference to the drawings are exemplary and intended to provide a more thorough and complete understanding of the disclosure of the invention, and should not be construed as limiting the invention. Furthermore, detailed descriptions of known techniques may be omitted where such details are not essential to the features of the illustrated invention.

[0014] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the prior art and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0015] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms "one," "an," "say," and "this" used herein may also include plural forms. It should be further understood that the terminology used in this application includes the presence of the stated feature, integer, step, operation, element, and / or component, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that the terminology used herein and / or includes all or any unit and all combinations of one or more associated listed items.

[0016] The technical solution of the present invention and how the technical solution solves the above-mentioned technical problems will be described in detail below with specific embodiments.

[0017] The present invention provides a method for manufacturing printed circuit boards with ball grid arrays, such as... Figure 1 As shown, it includes the following steps: S100: A grinding plate on a printed circuit board to complete resin-filled vias. The resin protruding from the board surface and the copper bumps around the holes are removed, and the remaining holes except for the resin-filled vias are drilled.

[0018] S200: Performs electroplating of the hole copper and surface copper on the printed circuit board, and completes the etching of the ball grid array position on the first side by means of image transfer.

[0019] S300: Thickens the copper and electroplats gold at the ball grid array position, and then completes the pattern fabrication of other positions on the printed circuit board after covering the ball grid array position with dry film.

[0020] The method for producing a printed circuit board with a ball grid array provided by the present invention uses image transfer to electroplate the positions of the ball grid array, then electroplate gold, and then etch patterns in other positions. This method can electroplate the copper thickness of the ball grid array positions higher, making them protrude from other positions on the printed circuit board, thereby improving the smoothness and fit of the printed circuit board during assembly.

[0021] Specifically, in one implementation of this invention, such as Figure 2 As shown, before the step of grinding the resin-filled vias on the printed circuit board, the following steps are also included: S110: The substrate is obtained by multiple laminations, and preliminary drilling is completed on the substrate. Back drilling is added to the holes that need to be filled with electroplating. Back drilling is to remove the unwanted copper from the original through holes, leaving the remaining copper.

[0022] S120: Electroplating of the hole copper is then performed through image transfer.

[0023] S130: Complete resin plugging. The holes are filled with a special resin, specifically by using an ink to fill the holes completely.

[0024] Furthermore, in conjunction with the foregoing embodiments and implementation methods, in another specific implementation of the present invention, the steps of thickening the copper and electroplating gold at the ball grid array positions include: exposing the ball grid array positions through a film, covering and protecting other positions with dry film, and then performing the electroplating operation.

[0025] Furthermore, in another specific implementation of the present invention, in conjunction with the foregoing embodiments and implementation methods, the steps of thickening the copper and electroplating gold at the ball grid array positions further include: developing the ball grid array positions using a film, then protecting other positions with a dry film, and finally electroplating gold at the ball grid array positions.

[0026] The following describes the manufacturing method of the printed circuit board with ball grid array provided by the present invention in more detailed steps: 1) Complete multiple laminations and manufacture the substrate using conventional printed circuit board manufacturing processes.

[0027] 2) Complete the Via drilling. Via holes are small holes in the PCB, mainly used for current flow.

[0028] 3) Add back drilling to holes that require POFV (Plating Over Filled Via).

[0029] 4) Complete the copper plating of the holes: The copper plating of the holes is performed by image transfer.

[0030] 5) Complete the resin plugging.

[0031] 6) After completing the resin-filled hole grinding, remove the resin protruding from the board surface and the copper protrusions after hole copper electroplating.

[0032] 7) Complete the via hole drilling (drill all holes except the POFV hole).

[0033] 8) Electroplated copper in the holes and on the surface.

[0034] 9) The etching of the BGA position on the TOP surface is completed by image transfer (the graphics in other positions are not etched, only the graphics of the BGA are etched).

[0035] 10) The copper thickness of the BGA position on the TOP surface is increased by means of image transfer.

[0036] 11) Electroplating gold on the BGA position of the TOP surface is completed by image transfer.

[0037] 12) Then, the graphics in other locations are created by image transfer (the BGA location on the TOP surface needs to be protected by the dry film).

[0038] 13) Proceed with the subsequent processes as normal.

[0039] refer to Figure 3 The key steps are described below: After the multilayer circuit board is laminated, POFV holes are drilled first. After drilling, the POFV holes are plugged with resin, and then electroplating is performed. Next, copper is electroplated, and the BGA locations are revealed using image transfer. Then, acid etching is used to etch the BGA pattern. The etched BGA locations are then revealed using image transfer, and the BGA locations are electroplated separately.

[0040] After the BGA locations are electroplated, a pattern transfer method is used to develop the BGA, and then the BGA locations are electroplated with gold. Next, another image transfer method is used to protect the BGA locations with a dry film, while the patterns for the non-BGA locations are developed for copper thickening. Finally, an alkaline etching method is used to etch the patterns from the non-BGA locations.

[0041] Those skilled in the art will understand that the steps, measures, and solutions in the various operations, methods, and processes discussed in this application can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and solutions in the various operations, methods, and processes discussed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and solutions in the prior art that are similar to those disclosed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0042] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0043] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for manufacturing a printed circuit board with a ball grid array, characterized in that, Includes the following steps: A grinding plate is used to complete the resin-filled holes on a printed circuit board. The resin protruding from the board surface and the copper bumps around the holes are removed, and the remaining holes except for the resin-filled holes are drilled. Electroplating of the hole copper and surface copper on the printed circuit board is performed, and etching of the ball grid array position on the first side is completed by image transfer. The copper thickness of the ball grid array position is increased and gold is electroplated. After the ball grid array position is covered with dry film, the pattern fabrication of other positions of the printed circuit board is completed.

2. The method for manufacturing a printed circuit board with a ball grid array according to claim 1, characterized in that, Before the step of grinding the plate to complete the resin-filled vias on the printed circuit board, the method further includes: The substrate is obtained by multiple laminations, and preliminary drilling is completed on the substrate. Back drilling is added to the holes that need to be filled by electroplating. Then, copper plating of the holes is performed through image transfer; Complete the resin plugging process.

3. The method for manufacturing a printed circuit board with a ball grid array according to claim 1, characterized in that, The steps of thickening the copper and electroplating gold at the ball grid array positions include: The positions of the ball grid array are exposed by using a film, while other positions are covered and protected with dry film before electroplating.

4. The method for manufacturing a printed circuit board with a ball grid array according to claim 1, characterized in that, The steps of thickening the copper and electroplating gold at the ball grid array positions include: The positions of the ball grid array are developed using a film, and other positions are protected with a dry film. Then, gold is electroplated at the positions of the ball grid array.

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