A method for manufacturing a blind slot containing a metallized insert hole
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-29
- Publication Date
- 2026-08-14
AI Technical Summary
[0003]盲槽内含金属化插件孔工艺是指在多层PCB中，通过特定的制造工艺与流程，在盲槽内形成金属化通孔，并实现盲槽内插件孔与其他任意网络电气连接，该工艺的主要难点在于制作盲槽内金属化插件孔的同时，需要满足其他通埋孔的制作，若采用常规的PI阻胶工艺，压合后盲槽内的金属化插件孔会有一头露在外面，在制作外层其他金属化孔通孔时过程的药水会浸透到插件孔内，对盲槽造成污染，且槽内会藏大量的药水，会对盲槽内其他焊盘与金属化孔造成腐蚀，生产加工时药水还会溢出的表层对表层的铜面造成严重污染，导致无法完成全流程的制作，成品良率低，为此特提供一种盲槽内含金属化插件孔的制作方法
1、该盲槽内含金属化插件孔的制作方法，通过优化整个金属化插件孔的制作流程，在前期层板压合制作时，在预设的盲槽底部位置进行盲槽内阻焊层制作，同时利用PI胶替代盲槽位置的PP胶，在层板压合后直接进行盲槽内外的所有孔钻孔，钻孔结束后再进行盲槽开窗，最后进行统一沉铜，由于盲槽内的阻焊层采用预先增大尺寸制作，与盲槽开设后进行阻焊层制作相比较，本方案的阻焊层能够更好地保护内部层板的表面图形，避免药液渗入，同时后期统一开孔和沉铜，无需分开沉铜制作，避免多次沉铜造成进一步腐蚀伤害，有效提升整个多层板的质量。
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Figure CN122579467A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of multilayer PCB processing technology, and in particular to a method for manufacturing a blind slot containing a metallized insertion hole. Background Technology
[0002] With the rapid development of microelectronics technology, blind slots in printed circuit boards are now a common product structure. However, the process of adding metallized through-holes in the blind slots has brought a series of problems to the printed circuit board production process.
[0003] The process of creating metallized vias within blind slots in multilayer PCBs involves forming metallized vias within blind slots through specific manufacturing processes and procedures. This allows for electrical connections between the vias within the blind slots and other network connections. The main challenge lies in simultaneously fabricating the metallized vias within the blind slots and other buried vias. If conventional PI resist bonding is used, one end of the metallized via in the blind slot will be exposed after lamination. During the fabrication of other metallized vias on the outer layer, the chemicals used in the process will seep into the vias, contaminating the blind slot. Furthermore, a large amount of chemicals will accumulate in the slot, corroding other pads and metallized vias within the blind slot. During production, the chemicals will also overflow onto the surface, severely contaminating the copper surface and making it impossible to complete the entire process, resulting in low yield. Therefore, a method for fabricating metallized vias within blind slots is provided. Summary of the Invention
[0004] The purpose of this invention is to provide a method for manufacturing a blind slot containing a metallized insert hole, so as to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing a blind slot containing a metallized insert hole, comprising the following steps: S1. Fabrication of inner blind slot solder resist layer; S2, PP window opening, PI tape covering, pressing; S3. Drill the external through hole of the blind groove, drill the internal insertion hole of the blind groove, and open the window in the blind groove; S4, copper plating: laser ablation to remove the copper layer outside the inner ring of the blind slot, followed by electroplating; S5. Outer layer graphic creation, and isolation creation between the inner wall of the blind groove and the outer layer graphic; S6. Remove the copper foil from the inner wall of the blind slot to complete the fabrication.
[0006] Preferably, in step S1, the inner blind groove solder resist layer is formed by coating the top of the preset layer with the blind groove solder resist layer and then curing it before the layer plates are pressed together, so that when multiple layers are pasted and pressed together, the blind groove solder resist layer is formed inside the multilayer board.
[0007] Preferably, when the blind slot solder resist layer is coated, it is precisely positioned to the blind slot opening position, and the area of the blind slot solder resist layer is larger than the blind slot opening size, so as to avoid the solution from contacting the circuit pattern on the surface of the board where the blind slot solder resist layer is located during the subsequent copper plating.
[0008] Preferably, when the blind slot solder resist layer is applied, a solder resist window is made at the position of the plug-in hole in the blind slot on the surface of the layer plate where the blind slot solder resist layer is located. The solder resist window is increased based on the size of the plug-in hole in the blind slot so that the hole ring at the top of the plug-in hole in the blind slot is exposed outside the blind slot solder resist layer.
[0009] Preferably, in step S2, PP adhesive is applied to the surface of the layer where the blind slot solder resist layer is located. Then, after precise positioning based on the blind slot opening position on the PP adhesive surface, a window is opened to form a blind slot exposure area. Then, PI adhesive is applied to the PP adhesive surface. After precise positioning based on the blind slot opening position, the PI adhesive is cut and the portion facing the preset blind slot opening position is retained to form a PI adhesive filling part. The PI adhesive filling part is pressed downward so that the PI adhesive filling part enters the blind slot exposure area.
[0010] Preferably, the PI glue filling part is the same size as the blind groove opening, so that the PI glue filling part can be completely removed after the blind groove opening; The exposed area of the blind groove is compensated to be larger than the opening size of the blind groove, so that when multiple layers are pressed together, there can be space for the PP glue to flow inward, so as to prevent the PP glue from entering the blind groove.
[0011] Preferably, in step S3, after the multiple layers are laminated, holes are drilled in the multiple layers at preset positions, and after drilling, a window is made at the blind groove position so that when drilling the insertion hole in the blind groove, the surface of the layer on which the blind groove solder mask layer is located is pressed and solidified by the layer, thereby avoiding bursting and burrs at the end of the metallized insertion hole in the blind groove when drilling. Then, the blind groove position is cut and a window is made to remove the cutting material and PI film of the layer above the blind groove solder mask layer to expose the blind groove and the metallized insertion hole in the blind groove.
[0012] Preferably, step S4 includes the following specific process; S41. After drilling and blind slot opening, the multilayer board is placed in copper immersion solution for copper immersion treatment so that copper layer is formed on the surface of the multilayer board, the external through holes of the blind slot and the insertion holes inside the blind slot. S42. After copper plating, laser ablation is used to burn off the chemical copper layer outside the insertion hole in the blind slot, and ablation compensation is performed on the pre-reserved hole ring at the top of the insertion hole in the blind slot to avoid copper removal from the hole ring. S43. Electroplating is performed on the multilayer board so that the areas where the copper layer is retained are electroplated to form a metallized thickening.
[0013] Preferably, step S5 involves etching the outer layer of the multilayer board to create a pattern, and then creating a blind groove to isolate the inner wall of the blind groove from the outer pattern.
[0014] Preferably, in step S5, after the outer layer of the multilayer board is electroplated, alkaline etching is performed. At the same time, an isolation layer is made between the inner sidewall of the blind slot and the outer layer pattern so that the inner sidewall is not connected to the copper layer on the surface. The copper plating layer on the sidewall of the blind slot can be removed around the entire circle by simply picking it with a tool.
[0015] The technical effects and advantages of this invention are as follows: 1. The method for manufacturing metallized insertion holes within the blind slot optimizes the entire metallized insertion hole manufacturing process. During the initial layer lamination process, the solder mask layer is fabricated at the bottom of the blind slot at a pre-defined location. PI adhesive is used instead of PP adhesive at the blind slot location. After layer lamination, all holes inside and outside the blind slot are drilled directly. After drilling, the blind slot is opened, and finally, uniform copper plating is performed. Because the solder mask layer within the blind slot is pre-enlarged, compared to fabricating the solder mask layer after the blind slot is opened, this solution provides better protection for the surface pattern of the internal layer, preventing solvent penetration. Furthermore, the uniform opening and copper plating in the later stages eliminate the need for separate copper plating processes, avoiding further corrosion damage from multiple copper plating processes and effectively improving the overall quality of the multilayer board.
[0016] 2. The method for manufacturing the metallized insertion hole in the blind groove involves drilling the external through hole and the internal insertion hole of the blind groove before opening the window. Therefore, the top of the pre-set internal insertion hole of the blind groove is actually squeezed and fixed by the upper layer plate, thereby avoiding the formation of burst holes and burrs at the end of the drilled hole on the end face, thus improving the end face quality of the internal insertion hole of the blind groove.
[0017] 3. The method for manufacturing the metallized insert hole in the blind groove involves cutting a window in the PP glue, which is larger than the blind groove size, to form an exposed blind groove area before laminating the layers. The reserved space in the exposed blind groove area provides an extension space for glue overflow during subsequent lamination. At the same time, the reserved position of the blind groove is occupied by PI glue, thereby preventing PP glue from entering the preset position of the blind groove. Furthermore, when opening the window in the blind groove later, the PI glue allows the waste material and PI glue cut from the top of the blind groove to be easily removed simultaneously after the cutting is completed, reducing the difficulty of waste material removal after opening the window and preventing damage to the blind groove caused by waste material removal.
[0018] 4. The method for manufacturing metallized insertion holes in the blind slot is to optimize the overall process by creating the solder mask layer and positioning the PI glue inside the blind slot before drilling, drilling the holes inside and outside the blind slot sequentially before opening the blind slot, and then uniformly depositing copper after opening the blind slot. This reduces the number of steps in the entire process and effectively improves the operation speed. Attached Figure Description
[0019] Figure 1 This is a flowchart illustrating the manufacturing method of the blind slot containing a metallized insert hole according to the present invention. Figure 2 This is a cross-sectional view of the internal structure of the multilayer board before drilling according to the present invention; Figure 3 This is a cross-sectional view of the internal structure of the multilayer board after drilling according to the present invention; Figure 4 This is a cross-sectional view of the internal structure of the multilayer board after the window is opened in the blind groove of the present invention. Figure 5 This is a schematic diagram of the cured blind groove solder resist layer on the surface of the layer plate where the bottom surface of the blind groove is located according to the present invention; Figure 6 This is a schematic diagram of the PI adhesive windowed on the surface of the layer plate where the bottom of the blind groove of the present invention is located; Figure 7 This is a schematic diagram showing the completion of the insertion hole opening inside the blind slot after the window is opened in the blind slot according to the present invention; Figure 8 This is a schematic diagram of copper plating inside the blind trench of the present invention; Figure 9 This is a schematic diagram of laser ablation within the blind groove of the present invention; Figure 10 This is a schematic diagram of the electroplating process inside the blind tank of the present invention. Figure 11 This is a schematic diagram showing the completed fabrication of the outer wall pattern of the multilayer board of the present invention; Figure 12 This is a schematic diagram of the removal of copper foil from the inner wall of the blind slot in this invention; Figure 13 This is a partially enlarged schematic diagram of the metallized insertion hole in the blind slot manufactured according to the present invention. Figure 14 This is a side cross-sectional view of the metallized hole in the blind slot of the multilayer board finally formed by the present invention. Detailed Implementation
[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0021] This invention provides, for example Figures 1-14 The method for manufacturing a blind slot containing a metallized insert hole, as shown, includes the following steps: S1. Fabrication of inner blind slot solder resist layer; S2, PP window opening, PI tape covering, pressing; S3. Drill the external through hole of the blind groove, drill the internal insertion hole of the blind groove, and open the window in the blind groove; S4, copper plating: laser ablation to remove the copper layer outside the inner ring of the blind slot, followed by electroplating; S5. Outer layer graphic creation, and isolation creation between the inner wall of the blind groove and the outer layer graphic; S6. Remove the copper foil from the inner wall of the blind slot to complete the fabrication.
[0022] Before laminating the layers, the inner layer blind slot solder mask layer in step S1 is applied to the top of the preset layer and cured. This ensures that when multiple layers are bonded and laminated, the blind slot solder mask layer is formed inside the multilayer board. Furthermore, the blind slot solder mask layer is precisely positioned at the blind slot opening position during application, and the area of the blind slot solder mask layer is larger than the blind slot opening size. This achieves over-coverage of the bottom area of the blind slot, effectively preventing the copper plating solution from seeping through the gap between the two layers and contacting the circuit pattern on the surface of the layer where the blind slot solder mask layer is located.
[0023] When applying the solder mask layer to the blind slot, solder mask openings are made at the positions of the plug-in holes in the blind slot on the surface of the layer where the solder mask layer is located. The solder mask openings are made larger to compensate for the size of the plug-in holes in the blind slot, so that the hole ring at the top of the plug-in hole in the blind slot is exposed outside the solder mask layer. This allows a copper layer to be formed on the hole ring and the surface of the plug-in hole in the blind slot during the subsequent copper plating process.
[0024] Step S2 involves applying PP adhesive to the surface of the layer where the blind groove solder resist layer is located. Then, after precisely positioning the PP adhesive surface based on the blind groove opening position, an opening is made to form the blind groove exposure area. Next, PI adhesive is applied to the PP adhesive surface. After precisely positioning the PI adhesive based on the blind groove opening position, the PI adhesive is cut, retaining the portion facing the preset blind groove opening position to form the PI adhesive filling part. The PI adhesive filling part is pressed downward so that it enters the blind groove exposure area. The blind groove exposure area is compensated to make its area larger than the blind groove opening size, so that when multiple layers are pressed together, there is room for PP adhesive to flow inward, thus preventing PP adhesive from entering the blind groove. The PI adhesive filling part is the same size as the blind groove opening, so that the PI adhesive filling part can be completely removed after the blind groove opening. This solves the problem of PP adhesive sticking and being unable to be peeled off when the blind groove is opened later. At the same time, the PI adhesive can be peeled off quickly without damaging the blind groove.
[0025] Step S3: After multiple layers are laminated, holes are drilled in the multiple layers according to preset positions. After drilling, windows are opened in the blind slot positions so that when drilling the insertion holes in the blind slot, the surface of the layer on which the solder mask layer of the blind slot is located is pressed and solidified by the layer, thereby avoiding bursting and burrs at the end of the metallized insertion hole in the blind slot when drilling. Then, the blind slot positions are cut and windows are opened to remove the cutting material and PI film of the layer above the solder mask layer of the blind slot, so as to expose the blind slot and the metallized insertion hole in the blind slot.
[0026] Step S4 includes the following specific process; S41. After drilling and blind slot opening, the multilayer board is placed in copper immersion solution for copper immersion treatment so that copper layer is formed on the surface of the multilayer board, the external through holes of the blind slot and the insertion holes inside the blind slot. S42. After copper plating, laser ablation is used to burn off the chemical copper layer outside the insertion holes in the blind slot of the multilayer board. The pre-reserved hole ring at the top of the insertion hole in the blind slot is ablated to compensate for the copper removal. S43. Electroplating is performed on the multilayer board so that the areas where the copper layer is retained are electroplated to form a metallized thickening.
[0027] Step S5 involves etching the outer layer of the multilayer board and creating a hollowing-out isolation between the inner wall of the blind trench and the outer layer pattern. Here, the inner wall of the blind trench and the outer layer pattern are isolated and compensated accordingly. After subsequent etching, the inner wall of the blind trench and the outer layer pattern cannot form a whole. At this time, the laser copper removal cannot remove copper from the blind trench sidewall parallel to the laser beam. After hollowing-out isolation, the inner wall is not connected to the surface copper layer. The copper plating layer of the blind trench sidewall can be removed around the entire circle by simply picking it with a trimmer.
[0028] Working principle: The method for manufacturing the metallized insertion hole in the blind slot involves first determining the position of the bottom layer of the blind slot based on the number of layers in the multilayer board and the preset depth of the blind slot. Then, layers and PP adhesive are stacked sequentially from bottom to top. When the stacking reaches the position of the bottom layer of the blind slot, the preset blind slot position is located using a target on the PCB board as a reference point. Then, the blind slot solder mask layer is fabricated at the blind slot position of the layer. It should be noted that the area of the blind slot solder mask layer needs to be increased so that the area of the blind slot solder mask layer is larger than the size of the blind slot. When fabricating the blind slot solder mask layer, a hole ring has been set for the preset insertion hole position in the blind slot on the surface of the layer board. A window is made in the blind slot solder mask layer at the hole ring, and the area of the window is larger than the area of the hole ring so that the hole ring is fully exposed. Then, the top PP adhesive is applied. Then, the PP adhesive is cut using laser milling. By controlling the laser beam energy, the laser cuts only the PP adhesive without damaging the underlying blind groove solder mask layer or the pattern on the layer board, thus forming a blind groove exposed area on the PP adhesive. It should be noted that the size of the blind groove exposed area should be larger than the size of the blind groove. Then, PI adhesive is pasted on the PP adhesive, with the PI adhesive having the same thickness as the PP adhesive. At this point, the PI adhesive is precisely cut according to the size of the blind groove. The PI adhesive in the non-blind groove position is removed after cutting. Then, the PI adhesive in the blind groove position is pressed down into the blind groove exposed area. At this point, the upper layer board and PP adhesive are pasted together until the number of layers reaches the preset number. At this time, the multi-layered plates are pressed together. When the PP glue in the same layer as the blind groove solder resist layer is squeezed, it will overflow into the preset blind groove. At this time, under the reserved space in the exposed area of the blind groove, there is an extension space reserved for the overflow of glue. At the same time, the reserved position of the blind groove is occupied by PI glue, so as to prevent PP glue from entering the preset position of the blind groove. Immediately after lamination, drilling is performed on the external through holes and internal insertion holes of the blind groove. The two are drilled separately, and a brand new drill bit is required for the internal insertion holes. By optimizing the drilling process, the drill bit initially rotates at high speed with a low feed rate to ensure the flatness of the end of the internal insertion hole. Then, the feed rate is increased for rapid drilling. In the middle and later stages, due to the increased hole depth, the material discharge and cooling effects deteriorate. At this point, the rotation speed and feed rate need to be reduced to complete the drilling. During this process, since the blind groove has not yet been opened, the top of the pre-set internal insertion hole is actually squeezed and fixed by the upper layer plate, thus avoiding the formation of burst holes and burrs at the end of the drilled hole, thereby improving the end face quality of the internal insertion hole. After all drilling operations are completed, the top shelf of the blind slot is cut to open the blind slot. At this time, with the help of PI glue, the waste shelf material and PI glue cut out from the top of the blind slot can be easily removed at the same time after the cutting is completed. Then the whole thing is placed in the copper plating solution for copper plating. After the copper plating is completed, the copper layer in the non-target area is removed by laser ablation. During the ablation process, the hole ring is compensated by opening a window to avoid removing the copper layer on the surface of the hole ring, so that the inner wall of the plug-in hole in the blind slot is metallized. Then electroplating is performed to make the metallization thicker and denser. Finally, the outer surface of the entire multilayer board is patterned. During the patterning process, the inner wall of the blind slot is isolated from the outer pattern. After the patterning is completed, the copper layer on the inner wall of the blind slot is lifted and removed by a trimmer.
[0029] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for manufacturing a blind slot containing a metallized insert hole, characterized in that, Includes the following steps: S1. Fabrication of inner blind slot solder resist layer; S2, PP window opening, PI tape covering, pressing; S3. Drill the external through hole of the blind groove, drill the internal insertion hole of the blind groove, and open the window in the blind groove; S4, copper plating: laser ablation to remove the copper layer outside the inner ring of the blind slot, followed by electroplating; S5. Outer layer graphic creation, and isolation creation between the inner wall of the blind groove and the outer layer graphic; S6. Remove the copper foil from the inner wall of the blind slot to complete the fabrication.
2. The method for manufacturing a blind slot containing a metallized insert hole according to claim 1, characterized in that, Before the layer plates are laminated, the inner blind groove solder resist layer of step S1 is coated on the top of the preset layer plate and then cured to form the blind groove solder resist layer, so that when multiple layers are pasted and laminated, the blind groove solder resist layer is formed inside the multilayer board.
3. The method for manufacturing a blind slot containing a metallized insert hole according to claim 2, characterized in that, When the blind slot solder resist layer is coated, it is precisely positioned at the blind slot opening position, and the area of the blind slot solder resist layer is larger than the blind slot opening size, so as to avoid the solution from contacting the circuit pattern on the surface of the board where the blind slot solder resist layer is located during the subsequent copper plating.
4. The method for manufacturing a blind slot containing a metallized insert hole according to claim 2, characterized in that, When the blind slot solder resist layer is applied, solder resist openings are made at the preset positions of the insertion holes in the blind slot on the surface of the layer where the blind slot solder resist layer is located. The solder resist openings are made by compensating for the size of the insertion holes in the blind slot, so that the hole ring at the top of the insertion holes in the blind slot is exposed outside the blind slot solder resist layer.
5. The method for manufacturing a blind slot containing a metallized insert hole according to claim 2, characterized in that, In step S2, PP adhesive is applied to the surface of the layer plate where the blind slot solder resist layer is located. Then, after precise positioning based on the blind slot opening position on the PP adhesive surface, a window is opened to form the blind slot exposure area. Then, PI adhesive is applied to the PP adhesive surface. After precise positioning based on the blind slot opening position, the PI adhesive is cut and the portion facing the preset blind slot opening position is retained to form the PI adhesive filling part. The PI adhesive filling part is pressed down so that the PI adhesive filling part enters the blind slot exposure area.
6. The method for manufacturing a blind slot containing a metallized insert hole according to claim 5, characterized in that, The PI glue filling part is the same size as the blind groove opening, so that the PI glue filling part can be completely removed after the blind groove opening; The exposed area of the blind groove is compensated to be larger than the opening size of the blind groove, so that when multiple layers are pressed together, there can be space for the PP glue to flow inward, so as to prevent the PP glue from entering the blind groove.
7. The method for manufacturing a blind slot containing a metallized insert hole according to claim 2, characterized in that, In step S3, after the multiple layers are laminated, holes are drilled in the multiple layers at preset positions. After drilling, a window is made at the blind groove position so that when drilling the insertion hole in the blind groove, the surface of the layer on which the blind groove solder mask layer is located is pressed and solidified by the layer, thereby avoiding bursting and burrs at the end of the metallized insertion hole in the blind groove when drilling. Then, the blind groove position is cut and a window is made to remove the cutting material and PI film of the layer above the blind groove solder mask layer to expose the blind groove and the metallized insertion hole in the blind groove.
8. A method for manufacturing a blind slot containing a metallized insert hole according to claim 7, characterized in that, Step S4 includes the following specific process; S41. After drilling and blind slot opening, the multilayer board is placed in copper immersion solution for copper immersion treatment so that copper layer is formed on the surface of the multilayer board, the external through holes of the blind slot and the insertion holes inside the blind slot. S42. After copper plating, laser ablation is used to burn off the chemical copper layer outside the insertion hole in the blind slot, and ablation compensation is performed on the pre-reserved hole ring at the top of the insertion hole in the blind slot to avoid copper removal from the hole ring. S43. Electroplating is performed on the multilayer board so that the areas where the copper layer is retained are electroplated to form a metallized thickening.
9. A method for manufacturing a blind slot containing a metallized insert hole according to claim 8, characterized in that, Step S5 involves etching the pattern on the outer layer of the multilayer board and creating a blind slot between the inner wall of the blind slot and the outer pattern.
10. A method for manufacturing a blind slot containing a metallized insert hole according to claim 9, characterized in that, In step S5, after the outer layer of the multilayer board is electroplated, alkaline etching is performed. At the same time, an isolation layer is made between the inner wall of the blind slot and the outer layer pattern so that the inner wall is not connected to the copper layer on the surface. The copper plating layer on the side wall of the blind slot can be removed by simply picking it with a tool.