Machine drilling operation method for improving heat dissipation of substrate

Abstract

The invention relates to a machine drilling operation method for improving heat dissipation of a substrate, which comprises the following steps of: providing a minimum skip drilling preset substrate thickness, and acquiring the shortest distance between hole centers to be drilled on the substrate as a hole pitch; when the thickness of the substrate is not smaller than the preset substrate thickness of the minimum drill jumping, a drill jumping distance is set, and the drill jumping distance is larger than the hole distance; a drilling path is obtained, the drilling path sequentially passes through all the holes, and the distance between the centers of the two adjacent holes in the front and back direction of the drilling path is not smaller than the drill jumping distance; and drilling the substrate in sequence according to the drilling path. According to the invention, by introducing the drill jumping spacing, adverse effects caused by substrate temperature rise due to excessive concentration in array drill holes can be avoided.

Description

Technical Field

[0001] This invention relates to a circuit board manufacturing method, and more particularly to a drilling operation method for improving heat dissipation of a substrate. Background Technology

[0002] The description in this section provides only background information related to the disclosure of this invention and does not constitute prior art.

[0003] In circuit board manufacturing, it is necessary to perform array drilling operations on the substrate. Currently, the drilling path is calculated by software to find the shortest total distance and the fastest speed, and the drilling path is output according to the specified rule path.

[0004] If the drilling method described above is followed, the high density of the drilled holes, with all the pre-drilled holes located in the same position on the substrate, may cause the substrate temperature to rise. In some cases, abnormalities such as hole misalignment, hole burrs, board bursting, board cracking, and board warping may even occur.

[0005] It should be noted that the above description of the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of this invention. Summary of the Invention

[0006] The purpose of this invention is to provide a drilling method for improving heat dissipation of a substrate. By introducing skip drilling spacing, the adverse effects caused by excessive concentration of drill holes in the array, which leads to increased substrate temperature, can be avoided.

[0007] To achieve the above objectives, the present invention discloses a drilling method for improving heat dissipation of a substrate, the drilling method comprising the following steps: Provide the minimum preset substrate thickness for skip drilling, and obtain the shortest distance between the centers of the holes to be drilled on the substrate as the hole spacing; When the thickness of the substrate is not less than the minimum skip drill preset substrate thickness, a skip drill spacing is set, and the skip drill spacing is greater than the hole spacing. Obtain a drilling path, wherein the drilling path passes through all holes in sequence, and the center-to-center distance between two adjacent holes along the drilling path is not less than the skip drilling distance. Drill holes in the substrate sequentially according to the drilling path.

[0008] As a further description of the above technical solution, in the step of "obtaining the drilling path, wherein the drilling path passes through all holes in sequence, and the center-to-center distance between two adjacent holes in the drilling path is not less than the skip drilling distance", if there are multiple different drilling paths that can pass through all holes, the drilling path with the shortest path length is selected.

[0009] As a further description of the above technical solution, in the step of "setting the skip drill spacing, wherein the skip drill spacing is greater than the hole spacing", the substrate thickness is obtained, and the size of the skip drill spacing is obtained based on the size of the substrate thickness.

[0010] As a further description of the above technical solution, the minimum skip drilling preset substrate thickness is 1.2mm, and the skip drilling spacing is the substrate thickness divided by 1.2.

[0011] As a further description of the above technical solution, the skip drilling distance is no greater than 1000um.

[0012] As a further description of the above technical solution, the aperture is 150um, the spacing of the skip drill is 1000um, and the thickness of the substrate is 1200um.

[0013] As a further description of the above technical solution, before the step of "drilling the substrate sequentially according to the drilling path", the steps of feeding material, feeding baking, and thin copper are also included.

[0014] As a further description of the above technical solution, in the step of "drilling the substrate sequentially according to the drilling path", the substrate is fixed around its perimeter with pins.

[0015] As a further description of the above technical solution, after the step of "drilling the substrate sequentially according to the drilling path", the substrate after drilling is baked to release stress.

[0016] As a further description of the above technical solution, a preset number of boreholes is provided. In the step of "obtaining a borehole path, wherein the borehole path passes through all holes in sequence and the center-to-center distance between two adjacent holes in the borehole path is not less than the skip-drilling distance", the actual number of boreholes is also obtained, and the actual number of boreholes is compared with the preset number of boreholes. When the actual number of boreholes is not greater than the preset number of boreholes, the borehole path is set to an N-shaped path with up-and-down turns. When the actual number of boreholes is greater than the preset number of boreholes, the borehole path is set to a mosquito coil-shaped path that circles outward from the center.

[0017] By employing the above technical solutions, the beneficial effects of the present invention are as follows: The drilling method for improving substrate heat dissipation of the present invention can avoid the adverse effects caused by excessive concentration of drill holes in the array, which leads to increased substrate temperature. The method of the present invention can replan the drilling path and appropriately extend it, thus dispersing the distance between two adjacent holes. Therefore, it can effectively avoid localized heating of the substrate caused by excessively concentrated drilling, thereby avoiding the aforementioned abnormal phenomena such as hole misalignment, hole burrs, board bursting, board cracking, and board warping.

[0018] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a complete drilling path diagram of a machine drilling method for improving heat dissipation of a substrate provided in the embodiments of this specification; in Figure 1 The numerical designations in the diagram represent the drilling sequence, ordered by numerical value from largest to smallest. Figure 1 The thick white line in the image represents the drilling path; Figure 2 This is a schematic diagram of an N-type drilling path for a machine drilling method to improve heat dissipation of a substrate, as provided in the embodiments of this specification. Figure 3 This is a schematic diagram of a mosquito coil-shaped drilling path for a machine drilling method to improve heat dissipation of a substrate, as provided in the embodiments of this specification. in Figure 2 , 3 The thick black line in the diagram represents the drilling path, and the arrow indicates the starting direction of the path. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0023] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should, as appropriate, include any combination of one or more of the related listed items.

[0024] Please see Figure 1 This embodiment provides a drilling method for improving heat dissipation of a substrate, which includes the following steps: Provide the minimum preset substrate thickness for skip drilling, and obtain the shortest distance between the centers of the holes to be drilled on the substrate as the hole spacing; When the thickness of the substrate is not less than the minimum skip drill preset substrate thickness, a skip drill spacing is set, and the skip drill spacing is greater than the hole spacing. Obtain a drilling path, wherein the drilling path passes through all holes in sequence, and the center-to-center distance between two adjacent holes along the drilling path is not less than the skip drilling distance. Drill holes in the substrate sequentially according to the drilling path.

[0025] Based on the above steps, specifically, after obtaining the corresponding substrate and drilling requirements, the hole spacing can be obtained in advance according to the array pattern of holes on the substrate. The hole spacing can be the distance between the centers of the two closest and adjacent holes among all the holes in the preset drilling.

[0026] Based on the above, a smaller hole spacing is obtained, and a longer skip drill spacing is set that is at least larger than the hole spacing.

[0027] The skip drilling distance is actually at least twice the hole spacing. Therefore, when planning the drilling path, it is possible to ensure that there is a sufficiently wide distance between two adjacent holes on the drilling path, so that at least one hole can be skipped in the middle.

[0028] In specific operations, such as Figure 1 As shown, the drilling equipment can start drilling from hole 1. After drilling is completed, it can move to hole 2 at a distance not less than the skip-drilling distance and drill thereafter, and so on, until hole 3 is completed, until all holes 20 of this batch are drilled. Holes 1-20 can be connected to form a drilling path with a turning line, and there is a distance not less than the skip-drilling distance between each pair of adjacent holes.

[0029] It is worth noting that before the above operations, a minimum preset substrate thickness for skip drilling needs to be set. In this embodiment, it is set to 1.2mm as needed. Skip drilling is only performed when the substrate thickness is not less than 1.2mm. The specific reason is that when the substrate thickness is less than 1.2mm, the heat dissipation of the substrate is relatively good, so skip drilling is unnecessary and avoids affecting processing efficiency.

[0030] Based on the above steps, by introducing skip drilling spacing, the adverse effects caused by excessive concentration of holes in the array drilling, leading to increased substrate temperature, can be avoided. In the method of this invention, the drilling path is replanned and appropriately extended, thus dispersing the distance between adjacent holes. This effectively avoids localized heating of the substrate caused by excessively concentrated drilling, thereby preventing the aforementioned abnormal phenomena such as hole misalignment, hole burrs, board bursting, board cracking, and board warping. In other words, existing substrate drilling generally follows the principle of closest adjacent holes, and the planned drilling path often does not include skip holes. In the case of array holes, the path planning on the substrate is generally a regular serpentine pattern. This easily leads to drilling multiple holes simultaneously in small local areas on the substrate, resulting in localized overheating or excessive localized stress on the substrate.

[0031] In another embodiment, in the step "obtaining the drilling path, wherein the drilling path sequentially passes through all holes, and the center-to-center distance between two adjacent holes along the drilling path is not less than the skip drilling distance", if multiple different drilling paths that can pass through all holes are included, the drilling path with the shortest path length is selected. For example... Figure 1 In the illustration of this application, the thick white line represents the drilling path. The overall path is a completely irregular broken line, following the rule that the total drilling path is shortest when the distance between two holes is greater than the drilling path length. This achieves both avoiding localized overheating and high efficiency.

[0032] In the step "Setting the skip drill spacing, wherein the skip drill spacing is greater than the hole spacing", the substrate thickness is obtained, and the size of the skip drill spacing is obtained based on the substrate thickness. Specifically, the size of the skip drill spacing is the substrate thickness divided by 1.2. The skip drill spacing is actually slightly smaller than the substrate thickness to achieve a balance between avoiding overheating and efficiency. The skip drill spacing in this application is mainly set based on the substrate thickness. That is, the thicker the substrate, the farther the skip drill spacing needs to be to avoid overheating when drilling holes in thick boards. Conversely, the thinner the substrate, the closer the skip drill spacing can be.

[0033] In one embodiment, the skip drill spacing is limited to no more than 1000 μm, as an excessively large skip drill spacing may affect processing efficiency. Specifically, the hole diameter is 150 μm, the skip drill spacing is 1000 μm, and the substrate thickness is 1200 μm. The 1000 μm skip drill spacing is significantly larger than the 150 μm hole diameter, allowing for a sufficiently long distance to be stretched between the two holes, thus preventing overheating.

[0034] During actual drilling, drilling is performed according to the drilling path output by the program, combined with the machine tool settings for spindle speed, tool speed, and drill bit life. UC-type drill bits are used, whose chip flutes are longer than those of ordinary drill bits. During cutting, smoother chip removal reduces frictional heat generation. The drill tip diameter is smaller than the beveled part (middle section) of the drill bit, significantly reducing the contact area between the drill bit and the hole wall, thus reducing frictional heat generation, hole wall contamination and roughness, and greatly reducing the risk of drill bit breakage. Simultaneously, a spindle speed of 160-200 rpm, an ascent speed of 300-500 mm / sec, and an descent speed of 100-167 mm / sec (adjusted according to plate thickness), a drill bit diameter of 0.1 mm to 0.35 mm, humidity of 50% to 60%, and a temperature of 20 to 24°C further aid in chip removal and drill bit cooling.

[0035] Before the step of "drilling the substrate sequentially according to the drilling path", the process includes material feeding, material baking, and thin copper plating. Specifically, the purpose of material feeding is for the material management department to prepare raw materials for feeding, and to put qualified raw materials into production; material baking is to remove moisture from the substrate, stabilize the dimensions, and prevent deformation or cracking of the board due to water expansion during subsequent hot pressing and drilling; thin copper plating is to adjust the copper layer thickness of the substrate to meet the requirements of subsequent electroplating / etching, ensure the uniformity of the copper layer on the board, and improve the quality of the hole walls and surface copper. The raw material board has a relatively thick copper layer, which needs to be properly processed to meet the hole copper / surface copper specifications required by the subsequent processes, and finally meet the customer's specifications.

[0036] In the step of "drilling holes in the substrate sequentially according to the drilling path," the substrate is secured around its perimeter with pins. The specific steps include first clamping the substrate with upper and lower plates and securing it with pins, which act as positioning pins, to prevent vibration, deviation, or warping during drilling. During the drilling operation, the pins remain stationary around the perimeter of the substrate, ensuring its position remains constant. After drilling is complete, the pins can be removed from the substrate, allowing the substrate to be separated.

[0037] Following the step of "drilling the substrate sequentially according to the drilling path," the process also includes checking the size, deviation, and accuracy of all holes. Specifically, if the hole diameter in this embodiment is set to 150µm, and the drilling is done by machine, the tolerance is checked to be within ±25µm. If this is not met, the hole diameter is non-compliant. Similarly, the depth of the hole from the surface to the target layer is checked, as well as whether the hole wall is smooth, has a copper layer, and is free of residue. If delamination, cracks, copper fragments, or tool marks are present, the hole is non-compliant. The above-mentioned hole inspection can be achieved using an optical image analysis instrument, utilizing an AOI system to check the hole diameter, position, and edge quality. Specifically, the inspection standards are: hole size deviation from customer specifications within 10µm, hole distance from center offset within 20µm, and hole accuracy process capability index (Cpk) not less than 1.33.

[0038] After drilling and inspection, a cleaning step is also included. Specifically, after machine drilling, plasma cleaning is performed. After inspection, the substrate is treated with plasma (30% carbon tetrafluoride, 55% oxygen, 25% argon, vacuum degree 60-70 Pa, time 3-4 min, power 700-750 watts, temperature 35-40℃, vacuum environment with no humidity control) to remove dust and burrs from the surface and inside of the holes, in order to ensure the quality of the hole walls.

[0039] In another embodiment, the substrate needs to be baked after drilling to release stress. Specifically, the baking temperature can be selected at 120±5℃, the humidity not exceeding 30%RH, using nitrogen gas with a purity of 99.9%, and the baking time is set at 1.5-2.0 hours. After natural cooling to 50℃, it is removed, which has the best stress release effect. The shear force and thermal effect of machine drilling cause deformation of the copper foil's microstructure, generating residual stress. Adding a secondary baking process can release this residual stress.

[0040] In fact, to ensure efficiency, the preliminary work of this invention also includes steps such as measurement, drawing matching, order acceptance and material cutting, program output, and process establishment. In the measurement step, relevant departments are responsible for receiving the customer's design documents, measuring key parameters such as hole diameter and plate thickness, and providing them to product personnel. In the drawing matching step, product personnel, based on the measured graphic information and relevant product information, coordinate with the customer to adjust the drawings, ensuring that the manufacturing capacity is sufficient for production. In the order acceptance and material cutting step, product personnel deploy the production process, delivery time, and key points within the factory. In the program output step, output personnel, based on the information provided by product personnel, and considering specific plate thickness, hole spacing, number of holes, etc. (and densely distributed machine-drilled holes), create a skip-drilling program to ensure that the machine-drilled hole path conforms to the skip-drilling spacing specified in this invention. Finally, after establishing the construction process, materials are issued and the manufacturing phase begins.

[0041] In another embodiment, a preset number of holes is also provided, wherein the number is set to 700,000 based on empirical data about the substrate size. In the step "obtaining the drilling path, wherein the drilling path sequentially passes through all holes, and the center-to-center distance between two adjacent holes along the drilling path is not less than the skip-drill distance", the actual number of holes is also obtained, and the actual number of holes is compared with the preset number of holes, such as... Figure 2 As shown, when the actual number of boreholes is not greater than the preset number of boreholes, the borehole path is set to an N-type with up-and-down reversals; as Figure 3 As shown, when the actual number of drilled holes is greater than the preset number of drilled holes, the drilling path is set to a mosquito coil shape, spiraling outwards from the center. Specifically, according to experimental tests on drilling accuracy, when the total number of holes is no more than 700,000, the N-type drilling accuracy is better; when the total number of holes is greater than 700,000, the drilling path with the outer and inner rings rotating in a mosquito coil shape has better drilling accuracy.

[0042] The accuracy tests for the two different drilling paths are shown in the table below. The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the contents of the present invention specification and drawings are included in the scope of the patent application of the present invention.

[0043] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0044] Although this application has been described by way of examples, those skilled in the art will know that this application has many modifications and variations without departing from the spirit of this application, and it is intended that the appended embodiments include these modifications and variations without departing from this application.

Claims

1. A drilling method for improving heat dissipation of a substrate, characterized in that, The drilling method for improving heat dissipation of the substrate includes the following steps: Provide the minimum preset substrate thickness for skip drilling, and obtain the closest distance between the centers of the holes to be drilled on the substrate as the hole spacing; When the thickness of the substrate is not less than the minimum skip drill preset substrate thickness, a skip drill spacing is set, and the skip drill spacing is greater than the hole spacing. Obtain a drilling path, wherein the drilling path passes through all holes in sequence, and the center-to-center distance between two adjacent holes along the drilling path is not less than the skip drilling distance; The substrate is drilled sequentially according to the drilling path.

2. The drilling method for improving heat dissipation of a substrate according to claim 1, characterized in that: In the step "obtain the drilling path, wherein the drilling path passes through all holes in sequence, and the center-to-center distance between two adjacent holes in the drilling path is not less than the skip drilling distance", if there are multiple different drilling paths that can pass through all holes, select the drilling path with the shortest path length.

3. The drilling method for improving heat dissipation of a substrate according to claim 1, characterized in that: In the step "Set the skip drill spacing, the skip drill spacing is greater than the hole spacing", the substrate thickness is obtained, and the size of the skip drill spacing is obtained based on the size of the substrate thickness.

4. The drilling method for improving heat dissipation of a substrate according to claim 3, characterized in that: The minimum skip drill preset substrate thickness is 1.2 mm, and the skip drill spacing is the substrate thickness divided by 1.

2.

5. The drilling method for improving heat dissipation of a substrate according to claim 4, characterized in that: The spacing between the skip drills is no greater than 1000um.

6. The drilling method for improving heat dissipation of a substrate according to claim 5, characterized in that: The aperture is 150µm, the spacing between the skip drills is 1000µm, and the thickness of the substrate is 1200µm.

7. The drilling method for improving heat dissipation of a substrate according to claim 1, characterized in that: Before the step of "drilling the substrate sequentially according to the drilling path", the steps of feeding material, feeding material baking, and thin copper are also included.

8. The drilling method for improving heat dissipation of a substrate according to claim 1, characterized in that: In the step of "drilling holes in the substrate sequentially according to the drilling path", the substrate is fixed around its perimeter with pins.

9. The drilling method for improving heat dissipation of a substrate according to claim 1, characterized in that: After the step of "drilling the substrate sequentially according to the drilling path", the substrate after drilling is baked to release stress.

10. The drilling method for improving heat dissipation of a substrate according to claim 1, characterized in that: A preset number of holes is provided. In the step "obtaining the drilling path, wherein the drilling path passes through all holes in sequence and the center-to-center distance between two adjacent holes in the drilling path is not less than the skip drilling distance", the actual number of holes is also obtained and compared with the preset number of holes. When the actual number of holes is not greater than the preset number of holes, the drilling path is set to an N-shape with up and down turns. When the actual number of holes is greater than the preset number of holes, the drilling path is set to a mosquito coil shape that surrounds from the center outward.

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