Method for embedding device on circuit board based on laser grooving

Abstract

The invention discloses a method for embedding a device on a circuit board based on laser grooving. The method comprises the following steps: S1, cutting: cutting a prepreg into a substrate according to a preset size; s2, laser grooving is conducted, specifically, a through groove is machined in the base body on a laser cutting platform to obtain a sample piece, and during machining, the upper surface of the base body is cut for the first time to form a first cutting groove with the longitudinal section being in a V shape and the opening width being D1; second cutting is conducted in the first cutting groove to penetrate through the lower surface of the base body to obtain a second cutting groove with the vertical side wall and the width D2, D2 is smaller than D1, and the first cutting groove and the second cutting groove are communicated to form a through groove; s3, cleaning the slotted hole; s4, bonding glue is pressed on the lower surface of the sample piece; s5, mounting a device in the through groove; s6, laminating a base material above the sample piece after the device is mounted; and S7, removing the bonding glue, pressing the base material on the side surface, and obtaining a layer of sample piece with the embedded device after appearance detection is qualified. When the device is embedded, the device is not easy to interfere with the side wall of the cutting groove so as not to tilt up, and the qualified rate of products is high.

Description

Technical Field

[0001] The invention belongs to the technical field of embedded components on circuit boards, and in particular relates to a method for embedding components on circuit boards based on laser grooving. Background Art

[0002] At present, in electronic devices, capacitors are usually used to store charge and provide power stability. The traditional way to install capacitors is to connect them to the circuit board through leads, but this installation method takes up more space and is easily interfered by the outside world. The embedded capacitor technology can significantly reduce the volume of the circuit board and improve the stability of the capacitor by embedding the capacitor into the inside of the circuit board. The implementation of the embedded capacitor technology requires some special process steps. First, a hole matching the size of the capacitor needs to be made on the surface of the circuit board. Then, the lead of the capacitor is inserted into the hole and fixed using appropriate welding technology. Finally, a cover layer is used to encapsulate the capacitor with the surface of the circuit board to ensure its safety and stability.

[0003] Holes and slots for embedding capacitor components can generally be processed by mechanical milling machines and laser cutting equipment. Mechanical milling machines are limited by the minimum milling cutter size and cannot process slots less than 1mm wide. When conventional laser cutting equipment processes through slots on materials thicker than 1mm, as the cutting depth increases, on the one hand, the laser processing energy is attenuated because the processing plane is not in the focus position, and on the other hand, the processed position will block part of the laser, resulting in laser energy attenuation when processing deep slots. Therefore, the side wall taper is large after grooving, which can easily cause deviation when the subsequent device is embedded, affecting the overall product yield.

[0004] Therefore, a new technology is needed to solve the problem in the prior art that when the embedded device contacts the side wall of the groove, interference is easily generated, thereby affecting the product qualification rate. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a method for embedding components on a circuit board based on laser grooving. When the external dimensions of the embedded components are close to the actual grooving dimensions, when the components are embedded, interference is not likely to occur when the components contact the side walls of the grooving, causing the components to warp up, and the product qualification rate is high.

[0006] The present invention adopts the following technical solutions:

[0007] A method for embedding a device on a circuit board based on laser grooving comprises the following steps:

[0008] S1. Cutting: Cutting the prepreg into a prepreg substrate of a preset size;

[0009] S2. Laser grooving: The substrate formed after cutting is fixed on a laser cutting platform, and a through groove is processed through the upper and lower surfaces of the substrate, and the through groove is processed to obtain a sample;

[0010] S21. According to the maximum groove width D1 required by the established document, a first cutting is performed in a designated area on the upper surface of the substrate, and a first groove having a tapered side wall is obtained after cutting, wherein the longitudinal section of the first groove is V-shaped;

[0011] S22. According to the groove width D2 required by the established document, a second cut is made downward in the first groove area and penetrates the lower surface of the substrate, and a second groove vertically arranged on the side wall is obtained after cutting, and the remaining part of the first groove is connected with the second groove to form the through groove, wherein D2 is smaller than D1;

[0012] S3. Cleaning the slots on the sample;

[0013] S4. Adhesive pressing: pre-pressing the lower surface of the sample with the adhesive, and then pressing quickly according to the established conditions;

[0014] S5. Mounting components: Mount corresponding components in the designated through slots according to the design drawings;

[0015] S6. Lamination of substrates: pre-laminating and laminating the upper surface of the sample with the mounted device in step S5 with the single-sided substrate, and then laminating according to predetermined conditions. After lamination, the insulating medium in the single-sided substrate can fill the gaps around the device.

[0016] S7. Adhesive removal: removing the adhesive on the lower surface of the sample after the substrate is pressed in step S6;

[0017] S8. Lamination of substrates: laminating and pre-pressing the surface after the adhesive is removed in step S7 with the single-sided substrate, and then laminating according to predetermined conditions;

[0018] S9. Appearance inspection: Perform appearance inspection. If the appearance inspection is qualified, a sample with a layer of device embedding can be obtained.

[0019] As a further improvement of the technical solution of the present invention, the prepreg is made of insulating material.

[0020] As a further improvement of the technical solution of the present invention, in step S2, the prepreg is fixed on the laser cutting platform by adsorption.

[0021] As a further improvement of the technical solution of the present invention, in step S21, the laser cutting power of the first cutting is 5w-6w, the laser scanning speed is 200mm / s-300mm / s, the laser cutting frequency is 45KHZ-55KHZ, the number of laser cutting times is 1-4 times, and the Z-axis height is set to 0mm.

[0022] As a further improvement of the technical solution of the present invention, in step S22, the laser cutting power of the second cutting is 3w-3.6w, the laser scanning speed is 250mm / s-350mm / s, the laser cutting frequency is 45KHZ-55KHZ, the number of laser cutting times is 3 times-6 times, and the Z-axis height is set to -0.001mm.

[0023] As a further improvement of the technical solution of the present invention, the difference between D1 and D2 is not less than 10 μm.

[0024] As a further improvement of the technical solution of the present invention, in step S2, the four side walls of the first groove are connected end to end in sequence to form a cone; and the connection node of two adjacent side walls of the second groove is an arc transition surface.

[0025] As a further improvement of the technical solution of the present invention, in step S2, the laser processing path for the first cutting and the laser processing path for the second cutting both include a first path and a second path, the first path is rectangular, the second path is a line segment, and the two ends of the second path are respectively connected to the opposite sides of the rectangle of the first path.

[0026] As a further improvement of the technical solution of the present invention, in step S2, the length of the first groove is equal to the length of the second groove.

[0027] As a further improvement of the technical solution of the present invention, in step S3, a plasma device is used to clean the slot holes.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] When the size of the embedded device is close to the actual groove size, the method of embedding the device based on laser groove on the circuit board of this scheme is adopted. When embedding the device, the device is placed in the through groove, and the lower part of the device is located in the second groove. The device will not contact the inclined side wall in the first groove and tilt up, thereby improving the qualified rate of the product. In addition, the inclined setting of the side wall of the first groove makes the embedding process of the device smoother, reduces the taper of the side wall of the first groove after laser cutting, and uses the adhesive fixing process instead of the welding fixing process after the device is embedded, solving the problem that the small-sized devices such as capacitors are prone to displacement when embedding based on laser deep groove cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The technology of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0031] Figure 1 It is a process flow chart of embedding devices based on laser grooving on a circuit board of the present invention;

[0032] Figure 2 It is a cross-sectional view of the grooving area and the laser processing paths for the first and second cuts.

[0033] Reference numerals:

[0034] 1-base; 11-through groove; 12-groove area;

[0035] 2- Adhesive glue;

[0036] 3- Single-sided substrate;

[0037] 4-Device;

[0038] 5-laser processing path for the first cutting; 51-first path; 52-second path;

[0039] 6-Laser processing path for the second cutting;

[0040] 7- Copper layer. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0042] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in the present invention are only relative to the relative positional relationship of the components of the present invention in the drawings.

[0043] Reference Figure 1 , a method for embedding a device on a circuit board based on laser grooving, comprising the following steps:

[0044] S1. Cutting: Cut the prepreg into a prepreg substrate 1 of a preset size. The prepreg is made of an insulating material, and the prepreg can preferably be an insulating medium such as ABF or PP.

[0045] S2. Laser grooving: Fix the substrate 1 formed after cutting on a laser cutting platform, and process a through groove 11 that passes through the upper and lower surfaces of the substrate 1. After the through groove 11 is processed, a sample is obtained. The prepreg is fixed on the laser cutting platform by adsorption. The number of through grooves on the substrate can be set according to the number of components to be embedded, and the size of each through groove can be determined according to the size of the components to be embedded.

[0046] S21. According to the maximum groove width D1 required by the established document, the first cutting is performed in the designated groove area 12 on the upper surface of the substrate 1, and the first groove with a tapered side wall is obtained after cutting. The longitudinal section of the first groove is V-shaped, and the four side walls of the first groove are connected end to end in sequence to form a cone. The length of the first groove is L. The laser processing path 5 of the first cutting includes a first path 51 and a second path 52. The first path 51 is rectangular, and the second path 52 is a line segment. The two ends of the second path 52 are respectively connected to the opposite sides of the rectangle of the first path 51. Among them, the corresponding laser grooving parameters can be confirmed according to the actual thickness of the substrate 1 in the groove area. The laser cutting power of the first cutting is 5w-6w, the laser scanning speed is 200mm / s-300mm / s, the laser cutting frequency is 45KHZ-55KHZ, the number of laser cutting is 1-4 times, and the Z-axis height is set to 0mm.

[0047] S22. According to the groove width D2 required by the established document, a second cut is made downward in the area of ​​the first groove and through the lower surface of the substrate 1, and a second groove with a vertically arranged side wall is obtained after cutting, and the connection node of the two adjacent side walls of the second groove is an arc transition surface. The remaining part of the first groove is connected with the second groove to form the through groove 11, wherein D2 is smaller than D1, the difference between D1 and D2 is not less than 10μm, and the difference between D1 and D2 can be selected as 10μm. The laser cutting power of the second cutting is 3w-3.6w, the laser scanning speed is 250mm / s-350mm / s, the laser cutting frequency is 45KHZ-55KHZ, the number of laser cutting times is 3-6 times, and the Z-axis height is set to -0.001mm. The Z-axis height in the first grooving process is set to 0mm. At this time, the laser is in the focus state on the processing surface. The Z-axis height of the second grooving process is set to -0.001mm. With this setting, after the first processing, the laser cutting equipment has time to adjust the Z-axis focal length. During the two processing periods, it avoids continuous accumulation of heat at the same processing position, which can effectively reduce the impact of thermal effects. The actual laser grooving parameters can be adjusted according to the thickness of the grooving medium. The length of the first grooving is equal to that of the second grooving, and the laser processing path 6 of the second cutting is similar to the laser processing path 5 of the first cutting in the horizontal direction. The shape of the laser processing path 6 of the second cutting and the laser processing path 5 of the first cutting are both composed of a rectangle + line segment. The purpose of adding line segments is to break up the cutting waste during processing and facilitate waste discharge after cutting.

[0048] As product packaging requires smaller and smaller product volumes, the precision and requirements for product processing are becoming more and more stringent, so the external dimensions of the embedded device 4 are getting closer and closer to the size of the slot body. When embedding the device 4, the four corners in the conventional groove are vertical right-angled edges or sharp corners. Therefore, after the conventional groove is adopted, the slot body presents an inverted trapezoidal body. When the actual device 4 is embedded, the device 4 in the slot body is slightly offset, and one corner of the device 4 will contact and interfere with one corner of the slot body and tilt, making it impossible to carry out subsequent embedding work. In this scheme, the two right-angled edges in the second groove are arc transitioned. After the groove is cut, the connection of the four corners presents a semi-cylindrical shape extending toward the outside of the groove and forming an arc transition surface. This can solve the problem that when the external dimensions of the embedded device 4 are close to the actual groove dimensions, when the device 4 is embedded, when the device 4 is slightly offset, one corner of the device 4 will extend into the semi-cylindrical position of one corner of the slot body, and will not interfere with the side wall of the through groove 11.

[0049] When the size of the embedded device 4 is close to the actual size of the second groove, when the device 4 is embedded, the lower part of the device 4 is located in the second groove, and the device 4 will not contact the inclined side wall in the first groove and tilt up, thereby improving the qualified rate of the product. In addition, the inclined setting of the side wall of the first groove makes the embedding process of the device 4 smoother. In addition, only the upper side wall of the through groove 11 is inclined, and the side wall of the first groove does not need to be connected to the bottom surface of the substrate 1, thereby reducing the taper of the side wall of the first groove after laser cutting.

[0050] S3. Use plasma equipment to clean each slot on the sample.

[0051] S4. Pressing with adhesive 2: The lower surface of the sample is first overlapped with the adhesive 2 for pre-pressing, and then quickly pressed according to the given conditions. The process of fixing the device 4 with adhesive 2 replaces the welding and fixing process after the device 4 is embedded, and solves the problem of easy displacement of small-sized devices 4 embedded in laser-cut deep grooves.

[0052] S5. Mounting components 4: Mount corresponding components 4 in the designated through slots 11 according to the design drawings, such as mounting capacitors in the through slots 11 .

[0053] S6. Lamination of substrates: The sample or substrate 1 on which the device 4 is mounted in step S5 is pre-laminated on the side of the upper surface thereof and the single-sided substrate 3, and then laminated according to predetermined conditions. After lamination, the insulating medium in the single-sided substrate 3 can fill the gaps around the device 4, thereby fixing the device 4. A copper layer 7 can be provided on the upper surface of the single-sided substrate 3, and the specific material for making the single-sided substrate 3 can be a material having a filling property during lamination.

[0054] S7. Removing the adhesive 2: removing the adhesive 2 on the lower surface of the sample after the substrate is pressed in step S6.

[0055] S8. Substrate lamination: The surface after the adhesive 2 is removed in step S7 is first overlapped and pre-pressed with the single-sided substrate 3, and then pressed according to the predetermined conditions to obtain a sample with a layer of embedded device 4. A copper layer 7 can be provided on the lower surface of the single-sided substrate 3.

[0056] S9. Appearance inspection: Perform appearance inspection. If the appearance inspection is qualified, a qualified sample with a layer of embedded device 4 can be obtained.

[0057] In one embodiment, the method of embedding devices based on laser grooving on a circuit board of the present scheme is adopted, and the specific values ​​of the corresponding laser grooving parameters are confirmed according to the thickness of the substrate 1 in the actual grooving area. The confirmed laser grooving parameters are input into the laser cutting machine and the production of the cutting processing file is completed. The cutting processing file includes the first grooving processing drawing and the second grooving processing drawing. The laser processing path 5 of the first cutting is recorded on the first grooving processing drawing, and the laser processing path 6 of the second cutting is recorded on the second grooving processing drawing. After the laser cutting equipment automatically grabs the positioning points on the substrate to accurately locate the processing area, it performs the first cutting process according to the first grooving processing drawing required by the established file. After the first cutting process, the laser cutting equipment performs the second cutting process according to the second grooving processing drawing required by the established file. In this embodiment, the slit length of the laser processing path 5 of the first cutting is B, and the slit width is A1. The slit length of the laser processing path 6 of the second cutting is B, and the slit width is A2=A1-60μm. The groove width recorded on the second grooving processing drawing is formed by reducing the groove width recorded on the first grooving processing drawing by 60μm. Figure 2 As shown. The Z-axis height in the first grooving process is set to 0mm, and the laser is in the focus state on the processing surface at this time. The Z-axis height of the second grooving process is set to -0.001mm. In this way, after the first processing, the laser cutting equipment has time to adjust the Z-axis focal length. During the two processing periods, it avoids continuous accumulation of heat at the same processing position, which can effectively reduce the impact of thermal effects. The planar shapes of the laser processing path 5 of the first cutting and the laser processing path 6 of the second cutting are both composed of a rectangle + line segment. The purpose of setting the line segment in the rectangle as a part of the processing path is to break up the cutting waste during processing to facilitate waste discharge after cutting. In this embodiment, the laser grooving parameters can be referred to in Table 1 below as shown in the laser grooving parameter reference table.

[0058] Table 1. Laser grooving parameter reference table

[0059]

[0060] For other contents of the method for embedding components on a circuit board based on laser grooving described in the present invention, please refer to the prior art and will not be described in detail here.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for embedding components on a circuit board based on laser grooving, characterized in that: The following steps are involved: S1. Cutting: Cutting the prepreg into a prepreg substrate of a preset size; S2. Laser grooving: The substrate formed after cutting is fixed on a laser cutting platform, and a through groove is processed through the upper and lower surfaces of the substrate, and the through groove is processed to obtain a sample; S21. According to the maximum groove width D1 required by the established document, a first cutting is performed in a designated area on the upper surface of the substrate, and a first groove having a tapered side wall is obtained after cutting, wherein the longitudinal section of the first groove is V-shaped; S22. According to the groove width D2 required by the established document, a second cut is made downward in the first groove area and penetrates the lower surface of the substrate, and a second groove vertically arranged on the side wall is obtained after cutting, and the remaining part of the first groove is connected with the second groove to form the through groove, wherein D2 is smaller than D1; S3. Cleaning the slots on the sample; S4. Adhesive pressing: pre-pressing the lower surface of the sample with the adhesive, and then pressing quickly according to the established conditions; S5. Mounting components: Mount corresponding components in the designated through slots according to the design drawings; S6. Lamination of substrates: pre-laminating and laminating the upper surface of the sample with the mounted device in step S5 with the single-sided substrate, and then laminating according to predetermined conditions. After lamination, the insulating medium in the single-sided substrate can fill the gaps around the device. S7. Adhesive removal: removing the adhesive on the lower surface of the sample after the substrate is pressed in step S6; S8. Lamination of substrates: laminating and pre-pressing the surface after the adhesive is removed in step S7 with the single-sided substrate, and then laminating according to predetermined conditions; S9. Appearance inspection: Perform appearance inspection. If the appearance inspection is qualified, a sample with a layer of device embedding can be obtained.

2. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: The prepreg is made of insulating material.

3. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: In step S2, the prepreg is fixed on the laser cutting platform by adsorption.

4. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: In step S21, the laser cutting power of the first cutting is 5w-6w, the laser scanning speed is 200mm / s-300mm / s, the laser cutting frequency is 45KHZ-55KHZ, the number of laser cutting times is 1-4 times, and the Z-axis height is set to 0mm.

5. The method for embedding components on a circuit board based on laser grooving according to claim 4, characterized in that: In step S22, the laser cutting power of the second cutting is 3w-3.6w, the laser scanning speed is 250mm / s-350mm / s, the laser cutting frequency is 45KHZ-55KHZ, the number of laser cutting times is 3-6 times, and the Z-axis height is set to -0.001mm.

6. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: The difference between D1 and D2 is not less than 10 μm.

7. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: In step S2, the four side walls of the first groove are connected end to end in sequence to form a cone; and the connection node of two adjacent side walls of the second groove is an arc transition surface.

8. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: In step S2, the laser processing path for the first cutting and the laser processing path for the second cutting both include a first path and a second path, the first path is rectangular, the second path is a line segment, and the two ends of the second path are respectively connected to the opposite sides of the rectangle of the first path.

9. The method for embedding components on a circuit board based on laser grooving according to claim 8, characterized in that: In step S2, the lengths of the first groove and the second groove are equal.

10. The method for embedding components on a circuit board based on laser grooving according to claim 1, characterized in that: In step S3, a plasma device is used to clean the slots.

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