A method for manufacturing a photovoltaic module printed circuit board with super-large aperture

Abstract

A method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture includes the following steps: STEP 101: Fabricating the first layer group L1-L2; STEP 102: Fabricating the second layer group L3-L4; STEP 103: Fabricating the third layer group L5-L6, wherein the resin plugging via fabrication steps are as follows: STEP 1031: Milling through holes for L5-L6, the diameter of the through holes being between 2mm and 12.1mm; STEP 1032: Metallizing the through holes; STEP 1033: Applying adhesive tape to one side of L6; STEP 1034: Punctured into the adhesive tape with a needle; STEP 1035: Covering the holes with drilled aluminum sheets and plugging the holes using a vacuum resin plugging machine; STEP 1036: Baking and curing after plugging, removing the adhesive tape and sanding smooth; STEP 104: Fabricating layers L7-L8; STEP 105: Lamination.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and in particular to a method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture. Background Technology

[0002] In the electronics industry, circuit boards have become an indispensable component. The primary function of a conventional PCB is to form the conductors that transmit information. As China's solar photovoltaic industry is now at the forefront globally, and the solar and wind power industries are developing rapidly, the number of PCBs used in these fields is gradually increasing, and the product requirements are becoming more stringent.

[0003] In the photovoltaic industry, the PCB designs for some photovoltaic modules are complex and the manufacturing processes are challenging. Particularly in the case of metal via plugging, the via diameters vary to achieve signal shielding. Generally, resin plugs with a diameter ≤1.0mm are relatively easy to meet requirements. However, when the diameter exceeds 1.0mm, it becomes difficult to achieve, resulting in PCBs with issues such as depressions, bubbles, and voids after plugging, affecting the reliability of subsequent electroplating and failing to fully meet product requirements. Summary of the Invention

[0004] In view of this, the present invention provides a method for manufacturing a photovoltaic module printed circuit board with an ultra-large aperture that can solve the above-mentioned technical problems.

[0005] A method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture includes the following steps:

[0006] STEP101: Fabrication of the first layer group L1-L2: Material cutting -- copper plating -- drilling -- inner layer circuitry -- etching -- molding -- browning / lamination;

[0007] STEP102: Fabrication of the second layer L3-L4: Material preparation -- Drilling -- Plasma -- PTH / Board electrode -- Resin plugging -- Inner layer circuitry -- Etching -- AOI -- Inner layer gold plating -- Lead pick-out -- Browning / lamination;

[0008] STEP 103: Fabrication of the third layer group L5-L6: Material preparation -- Copper reduction -- Drilling buried vias -- Plasma -- PTH / PCB electrode -- Resin-filled buried vias -- Inner layer circuitry -- Etching -- AOI -- Conductor picking -- Browning / lamination. The fabrication steps for resin-filled buried vias are as follows:

[0009] STEP1031: Mill through holes for L5-L6, wherein the diameter of the through holes is between 2mm and 12.1mm;

[0010] STEP1032: Metallize the via with a copper thickness of 25-30µm and a control aperture of 12.0+ / -0.05mm;

[0011] STEP1033: Apply high-temperature resistant tape to one side of L6 to block the through hole that needs to be filled with resin;

[0012] STEP 1034: Puncture the tape with a needle, the needle having a diameter of 0.1-0.2 mm, to release air.

[0013] STEP1035: Use a pre-drilled aluminum sheet to cover the hole, and then plug the hole using a vacuum resin plugging machine;

[0014] STEP1036: After plugging the holes, bake and cure the material, then remove the tape and sand it smooth.

[0015] STEP104: Fabrication of L7-L8 layers: material preparation -- inner layer circuitry -- etching -- browning / lamination;

[0016] STEP105: Lamination: Browning / Lamination L1-L8--Drilling--Forming--Plasma--PTH / Board Electrode--Outer Layer Circuitry--Etching--AOI--Surface Treatment--Drilling--Forming--Electrical Testing--Final Inspection.

[0017] Furthermore, in step STEP101, rivet holes are drilled simultaneously during drilling.

[0018] Furthermore, in step STEP102, PTH / plate electrical circuitry is performed twice.

[0019] Furthermore, after step STEP1306, a second hole plugging is performed after the first hole plugging, and the second hole plugging process is the same as the first hole plugging process.

[0020] Furthermore, in step STEP104, when the inner layer circuit is fabricated, the inner layer circuit is placed on layer L7, and layer L8 must be protected during the fabrication of the inner layer circuit.

[0021] Furthermore, in step STEP 1033, the tape is able to withstand high temperatures above 160°C.

[0022] Furthermore, the tape is a PI film.

[0023] Furthermore, L3, L1, and L8 undergo surface treatment, which is nickel-gold plating.

[0024] Furthermore, in step STEP 105, the process of controlling the depth of the front and back sides during molding includes the following steps:

[0025] STEP1051: First, gold plate the outer layers of L1-L8, that is, the surfaces of L1 and L8 are gold plated.

[0026] STEP1052: After gold plating, deep forming is performed. The depth of deep forming is calculated based on the thickness of each layer. After the depth is calculated, 0.1mm is subtracted to facilitate gradual adjustment during deep forming to achieve the required value.

[0027] STEP1053: Set up the mechanical milling groove;

[0028] STEP1054: Stepped blind slots are achieved by milling grooves on both sides to expose the gold plating layer of L3, the through blind hole of L7, and the blind hole of L6.

[0029] Compared with existing technologies, the present invention provides a method for manufacturing photovoltaic module printed circuit boards with ultra-large apertures. By attaching high-temperature resistant PI tape to the back of the L6 with large-diameter through holes, it can prevent resin from falling to the back or causing depressions when filling the large holes with resin, thus achieving an ultra-large aperture resin plugging process. At the same time, puncturing the tape with a needle before plugging the holes can solve the process problem of air bubbles in the resin plugging process. Therefore, the ultra-large apertures of the printed circuit boards manufactured by this method will not have problems such as depressions, air bubbles, or voids, and can meet the signal shielding effect design of photovoltaic module circuit boards. Detailed Implementation

[0030] The following provides a more detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0031] The present invention provides a method for manufacturing a photovoltaic module printed circuit board with an ultra-large aperture, which includes the following steps:

[0032] STEP101: Fabrication of the first layer group L1-L2: Material cutting -- copper plating -- drilling -- inner layer circuitry -- etching -- molding -- browning / lamination;

[0033] STEP102: Fabrication of the second layer L3-L4: Material preparation -- Drilling -- Plasma -- PTH / Board electrode -- Resin plugging -- Inner layer circuitry -- Etching -- AOI -- Inner layer gold plating -- Lead pick-out -- Browning / lamination;

[0034] STEP 103: Fabrication of the third layer group L5-L6: Material preparation -- Copper reduction -- Drilling buried vias -- Plasma -- PTH / PCB electrode -- Resin-filled buried vias -- Inner layer circuitry -- Etching -- AOI -- Conductor picking -- Browning / lamination. The fabrication steps for resin-filled buried vias are as follows:

[0035] STEP1031: Mill through holes for L5-L6, wherein the diameter of the through holes is between 2mm and 12.1mm;

[0036] STEP1032: Metallize the via with a copper thickness of 25-30µm and a control aperture of 12.0+ / -0.05mm;

[0037] STEP1033: Apply tape to one side of L6 to block the pores where resin needs to be inserted;

[0038] STEP1034: Puncture the tape with a needle, the diameter of which is 0.1-0.2 mm;

[0039] STEP1035: Use a pre-drilled aluminum sheet to cover the hole, and then plug the hole using a vacuum resin plugging machine;

[0040] STEP1036: After plugging the holes, bake and cure the material, then remove the tape and sand it smooth.

[0041] STEP104: Fabrication of L7-L8 layers: material preparation -- inner layer circuitry -- etching -- browning / lamination;

[0042] STEP105: Lamination: Browning / Lamination L1-L8--Drilling--Forming--Plasma--PTH / Board Electrode--Outer Layer Circuitry--Etching--AOI--Surface Treatment--Drilling--Forming--Electrical Testing--Final Inspection.

[0043] The four core layers used in this fabrication method, namely L1-L2, L3-L4, L5-L6, and L7-L8, have their large-diameter holes located on the third core layer, L5-L6. These holes, requiring resin plugging, have a diameter of 12.1 mm and are metallized (copper-plated) with a copper thickness ≥25 μm. L1-L2 are made of RF-10 2.023 mm¹ / O high-frequency board, L3-L4 can be made of RF-60 3.175 mm¹ / I high-frequency board, and L5-L6 and L7-L8 are both made of TLY-5 0.508 mm¹ / I high-frequency board. When laminating L1-L2, L3-L4, L5-L6, and L7-L8, three FR-28 high-frequency polypropylene (PP) boards can be laminated to obtain an eight-layer buried-blind-via microwave board.

[0044] In step STEP101, rivet holes are also drilled during drilling to be used during pressing for positioning purposes. This also helps to prevent misalignment of the four boards L1-L2, L3-L4, L5-L6, and L7-L8 during pressing.

[0045] In step STEP102, PTH / plate electrical circuitry is performed twice.

[0046] In step STEP1031, the diameter of the milled through hole is 12.1 mm.

[0047] In step STEP 1032, the milled through-hole is copper-plated, with the copper thickness ranging from 25 to 30 micrometers. This copper plating controls the diameter of the through-hole to be within 12.0 + / - 0.05 mm.

[0048] In step STEP 1033, the adhesive tape must be able to withstand temperatures above 160°C. Therefore, the adhesive tape can be a PI film resistant to 250°C or a red adhesive tape resistant to 200°C. By attaching the high-temperature resistant tape to one end of the through-hole, the resin can completely fill the through-hole when the resin plugs it, thus preventing it from falling off to the other side and avoiding depressions.

[0049] In step STEP 1034, by using a needle with a diameter of 0.1-0.2 mm to poke multiple holes in the adhesive tape, air can be released during resin plugging. By releasing the gas from the through-holes during resin plugging, voids in the resin after plugging are avoided due to incomplete or insufficient venting. Especially without adhesive tape, baking is often performed quickly to prevent resin from falling to the back, making it difficult to completely remove air from the resin. This can result in air bubbles in the through-holes, which can cause depressions if they are only released after plugging. However, by attaching the adhesive tape to one side of the through-hole, time is allowed for the gas to escape, thus preventing air bubbles from remaining in the resin. Furthermore, since no air bubbles are released after plugging, depressions are avoided, ensuring the plugged through-holes meet product requirements.

[0050] In step STEP 1035, the purpose of covering the drilled through-holes with an aluminum sheet is to prevent uneven copper thickness on the large copper surface due to repeated grinding, which could lead to exposed substrate in subsequent copper reduction processes, as well as expansion and contraction issues caused by repeated grinding. Because the resin-filled holes need to be ground smooth after filling, the copper surface would be manipulated without protection. Therefore, an aluminum sheet is needed to protect the copper surface; that is, an aluminum sheet with holes is placed on the core board, and the holes on the aluminum sheet are aligned with the drilled through-holes.

[0051] In step STEP 1036, a baking curing process is first performed at a temperature between 155°C and 230°C. Baking thoroughly cures the resin after plugging the holes. After curing, the tape is removed, and the resin in the through-hole is then smoothed using a grinding machine.

[0052] In addition, before step STEP 1306, since slight depressions may still exist after the first plugging, a second plugging is performed regardless of whether the hole protrudes to the outside or is depressed, to ensure that any potential depressions are eliminated. The second plugging process is the same as the first plugging process and will not be described again here.

[0053] In step STEP 104, when fabricating the inner layer circuitry, the inner layer circuitry is placed on layer L7. Simultaneously, layer L8 must be protected during the inner layer circuitry fabrication process to prevent it from being etched. The method for protecting L8 can be a dry film pressing followed by full-area exposure to protect the copper surface from etching; this is existing technology and will not be described in detail here.

[0054] In step STEP 105, the process of controlling the depth of the front and back sides during molding includes the following steps:

[0055] STEP1051: First, gold plate the outer layers of L1-L8, that is, the surfaces of L1 and L8 are gold plated.

[0056] STEP1052: After gold plating, deep forming is performed. The depth of deep forming is calculated based on the thickness of each layer. After the depth is calculated, 0.1mm is subtracted to facilitate gradual adjustment during deep forming to achieve the required value.

[0057] STEP1053: Set up the mechanical milling groove;

[0058] STEP1054: Stepped blind slots are achieved by milling grooves on both sides to expose the gold plating layer of L3, the through blind hole of L7, and the blind hole of L6.

[0059] In step STEP105, the pressed laminates can be joined by hot-melt riveting to ensure interlayer alignment.

[0060] In step STEP 105, after lamination, a diamond-coated drill bit can be selected for drilling to reduce the drill bit's lifespan. The lifespan of the drill bit is set to 200 holes for holes smaller than 0.6 mm and 60 holes for holes larger than 0.6 mm. A 0.15 mm coated aluminum sheet is used as a cover plate to effectively reduce the heat of the drill bit.

[0061] In step STEP106, all electroplating after pressing requires pulse electroplating. Pulse electroplating uses forward DC + reverse pulse + forward DC, with a high current density of 20 ASF, chloride ion controlled at 75±15 ppm, copper sulfate concentration of 65±10 g / L, and copper bath temperature of 21-25 degrees Celsius, set to 23 degrees Celsius. This allows for the satisfaction of hole copper while minimizing the increase in surface copper.

[0062] For inner layer electroplating, VCP vertical continuous plating is used. This board is 3.3mm thick, with a minimum drill bit of 0.4mm and an aspect ratio exceeding 8:1. To ensure deep plating capability, the jet frequency must be set to 40-65Hz, and appropriate current density and plating time must be set during VCP plating to ensure that the copper thickness in the holes is ≥12um.

[0063] After completing the outer layer automated optical inspection steps, four-line low-resistance testing, solder mask application, character marking, and surface treatment with tin plating are also required. Due to the board thickness and copper thickness exceeding the design structure of ordinary boards, the tin plating parameters must be set appropriately. After multiple verifications on test boards, the final settings were: immersion time of 6 seconds, preheating temperature of 150 degrees Celsius, and baking time of 60 minutes. After tin plating, the tin surface should be full and bright, without solder mask bridging, whitening of the tin surface, or excessive tin thickness.

[0064] Compared with existing technologies, the present invention provides a method for manufacturing photovoltaic module printed circuit boards with ultra-large apertures. By applying adhesive tape to the back of L6, which has a large-diameter through hole, resin can be prevented from falling to the back during resin plugging of large holes, thus achieving an ultra-large aperture resin plugging process. At the same time, puncturing the adhesive tape with a needle before plugging the hole solves the process problem of air bubbles in the resin plugging process. Therefore, the ultra-large apertures of the printed circuit board manufactured by this method after resin plugging will not have problems such as depressions, air bubbles, or voids, and can meet the design signal shielding effect of photovoltaic module circuit boards.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions or improvements within the spirit of the present invention are covered within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture, comprising the following steps: STEP101: Fabrication of the first layer group L1-L2: Material cutting -- copper plating -- drilling -- inner layer circuitry -- etching -- molding -- browning / lamination; STEP102: Fabrication of the second layer L3-L4: Material preparation -- Drilling -- Plasma -- PTH / Board electrode -- Resin plugging -- Inner layer circuitry -- Etching -- AOI -- Inner layer gold plating -- Lead pick-out -- Browning / lamination; STEP 103: Fabrication of the third layer group L5-L6: Material preparation -- Copper reduction -- Drilling buried vias -- Plasma -- PTH / PCB electroplating -- Resin-filled buried vias -- Inner layer circuitry -- Etching -- AOI -- Conductor picking -- Browning / lamination. The fabrication steps for resin-filled buried vias are as follows: STEP1031: Mill through holes in L5-L6, wherein the diameter of the through holes is between 2mm and 12.1mm; STEP1032: Metallize the via with a copper thickness of 25-30 μm and a control aperture of 12.0 ± 0.05 mm; STEP1033: Apply high-temperature resistant tape to one side of L6 to block the through hole that needs to be filled with resin; STEP 1034: Puncture the tape with a needle to plug the hole for venting; the needle has a diameter of 0.1-0.2 mm. STEP1035: Use a pre-drilled aluminum sheet to cover the hole, and then plug the hole using a vacuum resin plugging machine; STEP1036: After plugging the holes, bake and cure the material, then remove the tape and sand it smooth. STEP104: Fabrication of L7-L8 layers: material preparation -- inner layer circuitry -- etching -- browning / lamination; STEP105: Lamination: Browning / Lamination L1-L8--Drilling--Forming--Plasma--PTH / Board Electrode--Outer Layer Circuitry--Etching--AOI--Surface Treatment--Drilling--Forming--Electrical Testing--Final Inspection.

2. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: In step STEP101, rivet holes are drilled simultaneously during drilling.

3. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: In step STEP102, PTH / plate electrical circuitry is performed twice.

4. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: Before step STEP1036, a second hole plugging is performed after the first hole plugging. The second hole plugging process is the same as the first hole plugging process.

5. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: In step STEP104, when the inner layer circuit is fabricated, the inner layer circuit is placed on layer L7, and layer L8 is protected during the fabrication of the inner layer circuit.

6. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: In step STEP1033, the tape can withstand high temperatures above 160°C.

7. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: The tape is a high-temperature resistant PI film.

8. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: The L3, L1, and L8 are subjected to surface treatment, which is nickel-gold plating.

9. The method for manufacturing a photovoltaic module printed circuit board with ultra-large aperture as described in claim 1, characterized in that: In step STEP105, the process of controlling the depth of the front and back sides during molding includes the following steps: STEP1051: Gold plating on the outer layer surface of L1 and L8 layers; STEP1052: After gold plating, deep forming is performed. The depth of deep forming is calculated based on the thickness of each layer. After the depth is calculated, 0.1mm is subtracted to facilitate gradual adjustment during deep forming to achieve the required value. STEP1053: Perform mechanical milling; STEP1054: A stepped blind groove is created by milling grooves on both sides to expose the gold plating layer of L3, the through blind hole of L7, and the blind hole of L6.