A manufacturing method of a circuit board with high-precision metallization semi-hole at board edge

Abstract

The application discloses a manufacturing method of a circuit board with a high-precision metalized semi-hole at the board edge, which comprises the following steps: manufacturing a metalized hole at a design position corresponding to the semi-hole; performing first clockwise drilling and milling on the metalized hole of the circuit board from the hole to the hole wall of an invalid area, and passing through the intersection of a forming line and the hole wall; connecting the end of the first drilling and milling path and performing second drilling and milling in parallel to the direction of the forming line to form a second drilling and milling path, and forming a groove in the hole wall; forming a drilling and milling plate as a whole, flipping the drilling and milling plate, and performing milling along the forming line from one end of the groove to the hole to form the circuit board; the unique path design is adopted, the drilling and milling and the milling are both clockwise rotation, the cutting action on the hole wall is formed, the front and back are effectively matched, the pulling action on the hole wall during the milling is effectively avoided, and the problems such as burrs and burrs are avoided, and high-precision processing is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit board manufacturing, in particular to a manufacturing method of a circuit board with high-precision metalized half-hole on the board edge. BACKGROUND

[0002] For a type of power module circuit board, metalized half-hole is needed to realize direct welding of the hole edge and the main edge, which has the effect of saving connectors and space.

[0003] Currently, the manufacturing method of the circuit board generally forms the board edge first, then drills the half-hole by drilling, and further forms the metalized layer by electroplating. However, the manufacturing method of forming first and then drilling the half-hole, when drilling the half-hole, the drill cutter mills the board edge, and due to the excessive milling force of the milling cutter, burrs and burrs may occur at the top corner position of the half-hole, which may cause copper tumor and uneven electroplating in subsequent electroplating processing.

[0004] Therefore, in order to solve the above-mentioned problems, a manufacturing method of a circuit board with high-precision metalized half-hole on the board edge is needed. SUMMARY

[0005] The present application aims to solve the low processing precision of the existing technology of the board edge metalized half-hole, and proposes a manufacturing method of a circuit board with high-precision metalized half-hole on the board edge, which comprises the following steps:

[0006] The circuit board is designed with a forming line, the range of the forming line is an effective area, and the other area is an ineffective area, the effective area is the upper end, and the ineffective area is the lower end, and the corresponding left end and right end are formed with the upper end and the lower end as the reference direction;

[0007] S10: Drill a through hole at the design position of the half-hole corresponding to the forming line of the circuit board, and electroplate to form a metalized hole;

[0008] S20: Perform first drilling and milling on the circuit board to form a first drilling and milling path, the drilling direction of the first drilling and milling is clockwise; the first drilling and milling is to mill the hole wall of the metalized hole from the hole to the ineffective area in the direction range of the left end and the lower end, and passes through the intersection of the forming line and the hole wall; then, the second drilling and milling is performed from the right end to the left end at the end of the first drilling and milling path to form a second drilling and milling path, the second drilling and milling path is parallel to the forming line, and the hole wall forms a groove; and the whole forms a drilling and milling plate;

[0009] S30: Flip the drilling and milling plate, and then mill from one end of the groove to the hole in the direction of the forming line to form the circuit board.

[0010] Further, the metallized hole is a small hole, and the diameter of the small hole is 0.15mm to 0.5mm.

[0011] Further, the metallized hole includes a hole ring, and the size of the hole ring is 25μm to 105μm.

[0012] Further, the first drilling and milling and the second drilling and milling both use a single-blade drill bit.

[0013] Further, the distance between the second drilling and milling path and the forming line is 20μm to 50μm.

[0014] Further, the rotation speed of the first drilling and milling is 25krpm to 30krpm, preferably 28krpm; the feed speed is 0.3m / min to 0.7m / min, preferably 0.5m / min; the retreat speed is 7.0m / min to 9.0m / min, preferably 8.0m / min; and the moving speed is 0.4m / min to 0.6m / min, preferably 0.5m / min.

[0015] Further, the rotation speed of the second drilling and milling is 33krpm to 37krpm, preferably 35krpm; the feed speed is 0.8m / min to 1.2mm / min, preferably 1.0m / min; the retreat speed is 6.0m / min to 10.0m / min, preferably 8.0m / min; and the moving speed is 0.5m / min to 0.9m / min, preferably 0.7m / min.

[0016] Further, the milling uses a double-blade milling cutter.

[0017] Further, the double-blade milling cutter rotates clockwise.

[0018] Further, the rotation speed of the milling is 32krpm to 40krpm, preferably 37krpm; the feed speed is 0.6m / min to 1.0m / min, preferably 0.8m / min; the retreat speed is 20m / min to 25m / min, preferably 22m / min; and the moving speed is 1.0m / min to 1.4m / min, preferably 1.2m / min.

[0019] The technical scheme of the present application firstly processes the invalid area of the metallized hole by first drilling and milling and second drilling and milling, and finally forms a milling cut, so that the effective area forms a metallized half-hole, thereby avoiding direct milling of the metallized hole to form a metallized half-hole, and effectively improving the processing precision of the metallized half-hole; through a unique path design, the first drilling and milling and the second drilling and milling are connected to form a groove, the board is then flipped, the groove is the milling feed port at this time, and the drilling and milling and the milling are both designed to rotate clockwise, the entire processing process forms a cutting action on the hole wall, and the front and rear form effective cooperation, thereby effectively avoiding the pulling action on the hole wall during milling, and problems such as burrs and burrs, and realizing high-precision processing of a circuit board with a high-precision metallized half-hole on the board edge. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.

[0021] Figure 1 It is a process flow diagram;

[0022] Figure 2 It is a plan view of the metallized hole;

[0023] Figure 3 It is a plan view of the metallized hole drilled and milled on the front surface of the circuit board;

[0024] Figure 4 It is Figure 3 It is a partial enlarged view of the FD;

[0025] Figure 5 It is a design diagram of the first drilling and milling and the second drilling and milling of the metallized hole;

[0026] Figure 6 It is a design diagram of the first drilling and milling and the second drilling and milling of the metallized hole and the forming line relationship;

[0027] Figure 7 It is a plan view of the metallized hole milled on the back surface of the circuit board;

[0028] Figure 8 It is a plan view of the metallized half-hole.

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030]

[0031] The objectives, functional features and advantages of the present application will be further described with reference to the embodiments in combination with the accompanying drawings. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0033] It should be noted that all the directionality indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings). If the specific posture changes, the directionality indications also change accordingly.

[0034] In addition, the descriptions such as “first”, “second” and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as “first”, “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “plurality” is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0035] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0036] Please refer to Figure 1 , Figure 1 for the process flow diagram.

[0037] The manufacturing process of the embodiment of the present application includes the implementation of each step process in Figure 1 , and each step process in Figure 1 will be further described step by step.

[0038] Please refer to Figure 2 , Figure 2 for the planar schematic diagram of the metallized hole.

[0039] The circuit board of the present embodiment is designed with a forming line 100, the effective area is within the forming line 100, and the other area is the ineffective area. The effective area is the upper end, and the ineffective area is the lower end. The upper end and the lower end are the reference directions to form the corresponding left end and right end.

[0040] Step S10:

[0041] In the forming line 100 of the circuit board, a through hole is drilled at the design position of the half-hole, and is plated to form a metallized hole 200, to form a metallized hole plate 10. By first making a complete metallized hole 200, and cooperating with the milling in the later process, the metallized hole 200 in the effective area is formed into the required metallized half-hole 3010, providing a processing basis for the later process.

[0042] Optionally, the metallized hole is a small hole with a diameter of 0.15mm to 0.5mm. The present embodiment is directed to the technical process of a smaller diameter metallized hole. The adhesion of the copper layer on the wall of the small hole is relatively weak. Generally, the milling cutter has a larger diameter. If direct forming milling is used, it is more likely to cause problems such as pulling and tearing of the copper layer on the hole wall. In addition, the small hole is conducive to high-density processing of the effective space.

[0043] Optionally, a hole ring 210 is made for the metallized hole 200 to provide a connection function for the hole wall metal layer of the metallized half-hole 3010, and also provides a processable hole ring pattern basis for the present embodiment. The size of the hole ring 210 is 25μm to 105μm, which can provide sufficient contact surface area to ensure good welding performance, thereby reducing the failure probability caused by poor contact and achieving higher positioning accuracy. This is not only conducive to improving the yield.

[0044] Please refer to Figure 3 and Figure 6 , Figure 3 is a plan view of the milling of the metallized hole on the front surface of the circuit board; Figure 4 is a partial enlarged view of the FD of Figure 3 ; Figure 5 is a design diagram of the first drilling and milling and the second drilling and milling of the metallized hole; Figure 6 is a design diagram of the first drilling and milling, the second drilling and milling, and the forming line of the metallized hole.

[0045] Step S20:

[0046] The first drilling and milling is performed on the circuit board to form a first drilling and milling path 2010, and the rotation direction of the drill bit in the first drilling and milling is clockwise. The first drilling and milling is performed on the metalized hole 100 from the inside of the hole to the hole wall of the invalid area, so that the cutting edge of the drill bit forms a cutting force (rather than a pulling force) on the hole wall, preventing the hole wall from being pulled and torn, and preventing burrs or burrs from occurring. The angle of the first drilling and milling is in the range of the left end and the lower end (i.e., 20° to 80°), and passes through the intersection JD of the forming line 100 and the hole wall, exposing the substrate at the intersection JD, forming a pre-milling state, effectively avoiding the impact of the high speed of the milling cutter on the intersection JD of the left side of the circuit board during the milling and forming of the subsequent process, and preventing burrs, burrs and other problems from occurring on the edge of the metalized half-hole 3010.

[0047] The second drilling and milling is performed from the right end to the left end of the first drilling and milling path 2010, forming a second drilling and milling path 2020. The second drilling and milling path 2020 is parallel to the forming line 100, the hole wall forms a groove, and the whole forms a drilling plate 20. The process of forming the first step of milling the hole wall and the second step of milling the micro groove ensures that the copper layer of the hole wall is cleanly milled, effectively preventing the hole wall from being pulled during milling and causing burrs, burrs and other problems if it is processed simultaneously with the subsequent forming and milling.

[0048] Further, the first drilling and milling and the second drilling and milling both use single-edge drill bits, which produce less cutting waste and are easy to remove. This helps to reduce surface damage caused by cutting waste accumulation, resulting in a smoother hole wall and better drilling quality.

[0049] In the present embodiment, the second drilling and milling path 2020 has a remaining margin 2030 between the forming line 100, and the distance is 20 microns to 50 microns. On the one hand, it provides a milling force point for the milling cutter of the subsequent milling plate, preventing the milling cutter from causing unevenness in the plate edge due to empty milling. On the other hand, it also does not increase the unnecessary amount of material removal due to the large distance, effectively improving production efficiency and product quality.

[0050] Further, the rotation speed of the first drilling and milling is 25 krpm to 30 krpm, preferably 28 krpm; the feed speed is 0.3 m / min to 0.7 m / min, preferably 0.5 m / min; the withdrawal speed is 7.0 m / min to 9.0 m / min, preferably 8.0 m / min; and the movement speed is 0.4 m / min to 0.6 m / min, preferably 0.5 m / min.

[0051] Further, the rotation speed of the second drilling and milling is 33krpm to 37krpm, preferably 35krpm; the feed speed is 0.8m / min to 1.2mm / min, preferably 1.0m / min; the retreat speed is 6.0m / min to 10.0m / min, preferably 8.0m / min; and the moving speed is 0.5m / min to 0.9m / min, preferably 0.7m / min.

[0052] The first drilling and milling needs to mill the copper layer on the hole wall, and a relatively low rotation speed is used to form a fine milling, a relatively small feed speed and a relatively small retreat speed are used to form the minimum pulling damage to the hole wall; the first drilling and milling is to mill the groove in the invalid area, and a relatively large rotation speed, a relatively large feed speed and a retreat speed are used to realize high efficiency processing; by reasonably controlling the rotation speed of the cutting edge and the feed speed, material tearing caused by too fast can be avoided, so that better surface smoothness and flatness are obtained, and the faster but stable retreat speed not only improves the speed of a single process, but also improves the output rate of the production line as a whole.

[0053] Please refer to Figure 7 and Figure 8 , Figure 7 is a schematic diagram of milling the metallized hole on the back of the circuit board; Figure 8 is a schematic diagram of the planar structure of the metallized half hole.

[0054] Step S30:

[0055] The drilling and milling plate 20 is flipped, and then the milling is performed along the forming line 100 from one end of the groove to the inside of the hole, forming the circuit board 30.

[0056] The first drilling path 2010 of the previous process and the second drilling path 2020 communicate to form a groove, and the drilling and milling plate 20 is flipped, but the clockwise rotation direction of the milling cutter is not changed, at this time the groove is the feed port of the milling, the milling cutter first advances to the position of the hole edge that has been milled, and the remaining margin 2030 is trimmed and milled, and then advances to the hole wall for drilling and milling, and the milling uses a double-edge milling cutter and rotates clockwise (the same as the previous drilling), at this time the advancing direction of the milling cutter forms a cutting state with the hole wall, effectively avoiding the pulling effect on the hole wall during milling, and problems such as burrs and burrs.

[0057] Further, the rotation speed of the second drilling and milling is 33krpm to 37krpm, preferably 35krpm; the feed speed is 0.8m / min to 1.2mm / min, preferably 1.0m / min; the retreat speed is 6.0m / min to 10.0m / min, preferably 8.0m / min; and the moving speed is 0.5m / min to 0.9m / min, preferably 0.7m / min.

[0058] The above merely provides the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure variations or direct / indirect applications in other related technical fields, which are made based on the contents of the present application specification and drawings, shall fall within the patent protection scope of the present application.

Claims

1. A method for manufacturing a high-precision metallized half-hole circuit board with a board edge, wherein the circuit board is designed with a molding line, the area within the molding line is an effective area, and the rest of the area is an ineffective area, the effective area is the upper end, the ineffective area is the lower end, and the upper end and the lower end are used as reference directions to form the corresponding left end and right end; characterized in that: The manufacturing method comprises the following steps: S10: drilling a through hole at a design position of the semi-hole corresponding to the forming line of the circuit board, and electroplating to form a metallized hole; the metallized hole comprises a hole ring; S20: performing first drilling and milling on the circuit board to form a first drilling and milling path, and the rotation direction of the drill bit of the first drilling and milling is clockwise; The first drilling and milling is to mill the hole wall of the metallized hole from the hole to the invalid area in the direction range of the left end and the lower end, and pass through the intersection of the forming line and the hole wall; The end of the first drilling and milling path is connected to the second drilling and milling from the right end to the left end to form a second drilling and milling path, the second drilling and milling path is parallel to the forming line, and the hole wall forms a groove; Form a drilling and milling plate as a whole; S30: flip the drilling and milling plate, and then mill from one end of the groove to the hole in the direction along the forming line to form the circuit board.

2. The method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 1, characterized in that: The metallized hole is a small hole, and the diameter of the small hole is 0.15mm to 0.5mm.

3. A method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 1 or 2, characterized in that: The size of the hole ring is 25μm to 105μm.

4. The method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 1, wherein: The first drilling and milling and the second drilling and milling both use a single-blade drill bit.

5. The method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 1, wherein: The distance between the second drilling and milling path and the forming line is 20μm to 50μm.

6. The method of claim 1, wherein the method further comprises: after the step of applying the solder mask, applying a solder resist to the solder mask; and after the step of applying the solder resist, applying a solder paste to the solder resist. 5 The rotation speed of the first drilling and milling is 25krpm to 30krpm; The feed speed is 0.3m / min to 0.7m / min; The retreat speed is 7.0m / min to 9.0m / min; The moving speed is 0.4m / min to 0.6m / min.

7. The method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 1, characterized in that: The rotation speed of the second drilling and milling is 33krpm to 37krpm; The feed speed is 0.8m / min to 1.2mm / min; The retreat speed is 6.0m / min to 10.0m / min; The moving speed is 0.5m / min to 0.9m / min.

8. The method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 1, wherein: The milling uses a double-blade milling cutter.

9. The method for manufacturing a half-hole circuit board with high-precision metallized board edges according to claim 8, characterized in that: The double-blade milling cutter rotates clockwise.

10. The method of claim 1 or 9, wherein the method further comprises: The rotation speed of the milling is 32krpm to 40krpm; ​ The feed speed is 0.6m / min to 1.0m / min; The retreat speed is 20m / min to 25m / min; The moving speed is 1.0m / min to 1.4m / min.

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