Manufacturing method of super high-rise three-step buried one-step blind hole back drilling HDI plate
Through the method of layered production and three-time pressing, combined with micropore design and advanced technology, the technical problems such as blind hole copper-coated core plating on the high-density level of HDI boards are solved, and the copper plating does not come into contact with the substrate copper is achieved, achieving high-density interconnection and high-electrical efficiency HDI board production.
Patent Information
- Application Number
- CN202510008847.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-05-16
AI Technical Summary
It is difficult to achieve effective technical problems such as blind hole copper-core plating at high density level, copper plating does not come into contact with the base copper, thin/uneven copper, and depression, and it is difficult to achieve high-density interconnection and high electrical efficiency while reducing costs.
The layered production method is adopted to achieve the production of buried holes in the inner layer and blind holes in each layer through three pressings, reducing the number of back drilling times, combining micropore design and advanced technologies such as laser drilling, hole filling electroplating, etc. to achieve high-density interconnection.
It realizes high-density interconnection, electrical efficiency and signal accuracy higher than traditional PCBs, and at the same time reduces costs, solving technical problems such as blind-hole copper-plated core-plated copper-plated core-free, and non-contact copper-plated copper-plated substrate copper.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of circuit board manufacturing, and in particular to a manufacturing method of an ultra-high-layer three-level buried first-level blind via back-drilled HDI board. Background Art
[0002] In the electronics industry, circuit boards have become an indispensable component, among which the HDI board, or high-density interconnect board, is a compact circuit board product with a relatively high line distribution density using micro-blind buried hole technology.
[0003] When the density of PCB increases to more than eight layers, the cost of manufacturing with HDI will be lower than the traditional complex lamination process. At the same time, the electrical performance and signal accuracy of HDI boards are higher than traditional PCBs. In addition, HDI boards have better improvements in radio frequency interference, electromagnetic interference, electrostatic discharge, thermal conduction, etc. High-density integration (HDI) technology can make the design of terminal products more miniaturized while meeting higher standards of electronic performance and efficiency. Ordinary first-order HDI boards are relatively simple, and the process and technology are easy to control. Summary of the invention
[0004] In view of this, the present invention provides a method for manufacturing an ultra-high-layer three-level buried one-level blind via back-drilled HDI board that can solve the above technical problems.
[0005] A method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board comprises the following steps: STEP101: Cutting - inner layer circuit - inner layer acid etching - AOI - browning - first pressing L2-9 - drilling - plasma - PTH - copper - resin plugging - circuit - AOI - browning; STEP102: Cutting--Inner layer circuit--Inner layer acid etching--AOI--Brown--Second lamination L12-19--Drilling--Plasma--PTH--One copper--Resin plugging--Circuit--AOI--Brown; STEP103: Press L2-L19 for the second time; STEP104: copper reduction--L2-19 layer drilling--plasma--PTH--board electricity--resin plugging--copper reduction--circuit / etching--third pressing, that is, pressing L2-L9 with L12 to L19 together; STEP105: Transfer to outer layer production: copper reduction after lamination -- L1-2, L19-20 layer laser drilling -- plasma -- filling plating -- copper reduction -- drilling -- plasma -- PTH -- pulse plating -- outer layer circuit -- graphic plating -- etching -- AOI -- solder mask -- text -- tin spraying -- testing -- molding -- final inspection.
[0006] Furthermore, in step STEP101, the width of the L2 line is determined according to the average value of the measured expansion and contraction data of L2-L9.
[0007] Furthermore, in step STEP 102 , the widths of the lines of the L10 , L11 , and L19 layers are determined according to the average value of the measured expansion and contraction data of L12 - L19 .
[0008] Furthermore, before step STEP104, the copper thickness on the surface of the L2 and L19 layers is reduced to 17-23 um.
[0009] Furthermore, in step STEP 104 , the copper thickness in the copper hole is reduced to 35-40 um.
[0010] Furthermore, during the first, second and third pressing, the pressing heating rate is controlled within the range of 2.0±0.5℃ / min, the temperature of the pressed material is controlled within the range of 80-140℃, the maximum pressure is 420PSI, and when the temperature of the outer layer material is between 80-100℃, high pressure is applied. The curing temperature should be greater than or equal to 195℃, and the curing time should be greater than or equal to 60min.
[0011] Furthermore, silicone pad-type pressing is used in the first, second and third pressing to make the plate thickness more uniform, and the thickness of the dielectric layer of the sub-outer layer, i.e., the L1-L2 and L19-L20 layers, is controlled to 0.1 mm ± 10%.
[0012] Furthermore, during the third pressing, the pressed layers L2-L9 and L12-L19 should be riveted first. The riveting is done by first using a high-precision electromagnetic hot melt machine to rivet the layers together, and then reinforcing them with rivets to prevent sliding or deviation during the hot pressing process.
[0013] Furthermore, during drilling, the center of the hole plate is hollowed out by etching in the inner layer design to reduce the copper thickness.
[0014] Compared with the prior art, the manufacturing method of the twenty-layer three-step buried first-step blind via back-drilled HDI board provided by the present invention adopts a hierarchical manufacturing method to reduce the number of back drilling times, avoid back drilling to the circuit that cannot be avoided, and at the same time ensure the copper thickness requirements of the inner layer blind vias. In addition, through three times of pressing, on the one hand, the production of inner layer buried vias can be realized, and on the other hand, it is convenient to make blind vias of each layer, and solve the technical problems such as blind via copper plating core, copper plating and substrate copper not contacting, thin / uneven copper, and depression. For the secondary outer layer micro-via buried vias, the micro-via design can achieve very high path density with fewer layers, reduce the overall size, improve the benefits of assembly, space utilization, etc., and realize high-density interconnection. Interconnection is achieved through conductive through holes, buried vias and blind vias, which is different from ordinary multi-layer circuit boards in structure, and a large number of micro-buried blind vias, laser drilling, hole filling electroplating and other advanced technologies are used in the secondary product to achieve interconnection density, so that its electrical performance and signal correctness are higher than traditional PCBs. DETAILED DESCRIPTION
[0015] The specific embodiments of the present invention are further described in detail below. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the protection scope of the present invention.
[0016] The present invention provides a method for manufacturing an ultra-high-layer three-level buried first-level blind via back-drilled HDI board, which comprises the following steps: STEP101: Cutting - inner layer circuit - inner layer acid etching - AOI - browning - first pressing L2-9 - drilling - plasma - PTH - copper - resin plugging - circuit - AOI - browning; STEP102: Cutting--Inner layer circuit--Inner layer acid etching--AOI--Brown--Second lamination L12-19--Drilling--Plasma--PTH--One copper--Resin plugging--Circuit--AOI--Brown; STEP103: Press L2-L19 for the second time; STEP104: copper reduction -- L2-19 layer drilling -- plasma -- PTH -- board electricity -- resin plugging -- copper reduction -- circuit / etching -- third lamination; STEP105: Transfer to outer layer production: copper reduction after lamination -- L1-2, L19-20 layer laser drilling -- plasma -- filling plating -- copper reduction -- drilling -- plasma -- PTH -- pulse plating -- outer layer circuit -- graphic plating -- etching -- AOI -- solder mask -- text -- tin spraying -- testing -- molding -- final inspection.
[0017] In steps STEP101 and STEP102, the material used for L2--L9, L12--L19 can be S1000-2M FR-4 0.1 2 / 2 without copper. After cutting, the inner layer circuits are directly placed on the L2--L9, L12--L19 layers. The inner layer adopts LDI imaging technology. The free expansion and contraction function of LDI can avoid the defects of insufficient positioning accuracy of traditional exposure machines. The positioning accuracy can reach within 50um to meet the compact and high-density interconnection characteristics of the product. The inner layer substrate thickness is 0.1mm, and the copper thickness is 2 ounces. During etching, film stripping, and browning, the drag board is added to the machine; the inner layer line width tolerance is controlled at ±1mil. During the operation, hold the board with both hands to prevent the substrate from breaking during the circulation process. Scratches, chemical contamination, water vapor, and other problems are not allowed. At the same time, during the design, the widths of L10, L11, and L19 lines are determined according to the average value of the measured expansion and contraction data of L12-19, and the width of L2 line is determined according to the average value of the measured expansion and contraction data of L2-L9.
[0018] In steps STEP101, STEP102, and STEP103, the lamination method and parameters are as follows: (1) The heating rate of pressing is controlled within the range of 2.0±0.5℃ / min, the temperature of the pressed material is controlled within the range of 80~140℃, the maximum pressure is 420PSI, and when the temperature of the outer layer material is between 80-100℃, high pressure is applied. The curing temperature should be greater than or equal to 195℃, and the curing time should be greater than or equal to 60min.
[0019] (2) Since the product has 20 layers and the total board thickness reaches 3.4mm, the inner copper thickness is controlled at 70-75um, and the amount of glue filling is large, it is easy to have uneven glue flow and cause voids in the board. Therefore, silicone pad pressing is used in the board thickness pressing to make the board thickness more uniform. The thickness of the dielectric layer of the second outer layer, i.e., the L1-L2 and L19-L20 layers, is controlled to 0.1mm±10%, reducing the difficulty of subsequent laser drilling and regulating electroplating.
[0020] (3) Interlayer alignment: This product is an HDI board, which is a compact, high-density interconnected PCB product with dense inner layer routing and a minimum spacing of 6.6 mil. Therefore, the new process method used for interlayer alignment is: due to the layered production of blind holes, namely three blind holes and one buried hole, plus three times of pressing, the interlayer alignment becomes the top priority during the riveting process. If there is an offset, it will cause a short circuit. For this reason, the riveting is first riveted together with a high-precision electromagnetic hot melt machine, and then reinforced with rivets for the second time, so that there will be no sliding or offset during the hot pressing process, ensuring the accuracy of interlayer alignment. In addition, in order to ensure the uniformity of pressing, the pressing heating rate is controlled within the range of 2.0±0.5℃ / min, the material temperature is controlled within the range of 80~140℃, the maximum pressure is 420PSI, the outer layer material temperature is switched to high pressure at 80-100℃, the curing temperature is ≥195℃, and the curing time is ≥60min.
[0021] In step STEP104, the outer layer drilling and filling methods and parameters are as follows: (1) In order to improve efficiency and ensure stable quality, laser drilling technology is used for clock holes, with a minimum hole diameter of 0.15mm. The hole filling method is sky plating, and the hole filling requirement is: concave ≤0.5mil; (2) For the outer through holes: The copper thickness of the inner layer of this HDI board is 2 ounces, and the total copper thickness of the finished product of this HDI board is greater than 36 ounces, which can easily lead to tool breakage, rough hole wall, and flash during the drilling process. For this reason, the middle of the hole plate is hollowed out by etching in the inner layer design, which can effectively reduce the copper thickness and reduce the wear of the drill needle, improve the quality, so that the drill needle can remove chips cleanly without breaking the needle, and the hole thickness will be less than 30um and there will be no nail heads.
[0022] After the third lamination of this HDI board is completed, the total board thickness will reach more than 3.4mm, and the minimum hole diameter will be less than 0.59mm. At the same time, in order to ensure that the hole copper meets the requirements and the surface copper thickness can meet the requirements of etching ability, pulse electroplating operation is required to improve the through-hole ability of the solution.
[0023] In step STE105, electrical performance test and appearance inspection are required, specifically: (1) After the outer layer is etched, a mid-test process is added to test the network connectivity; (2) After the product is finished, perform thermal shock test, hot and cold cycle test, reflow test, slice measurement of blind buried hole / through hole copper thickness, surface copper thickness, hole diameter, molding size, etc. according to GJB362C-2021 and QJ831B-2011; (3) Check appearance problems according to GJB362C-2021 and QJ831B-2011.
[0024] At the same time, in the pulse electroplating step of step STEP105, in order to ensure that the hole copper meets the customer's requirements and the surface copper thickness can meet the requirements of etching ability, pulse electroplating operation is adopted to improve the through-hole ability of the solution.
[0025] In steps STEP101, STEP102, and STEP103, expansion and shrinkage control is also required. Because the product is a high-density interconnected HDI board, and a hierarchical production solution is adopted, it requires three presses. Therefore, the standard for expansion and shrinkage control is: first reserve an 80,000th shrinkage for the inner layer graphics of the L2--L9 and L12-19 layers as a whole, and measure the actual expansion and shrinkage of the two sub-layers of "L2--L9, L12-19" after the first press is completed. According to the average expansion and shrinkage of the two sub-layers, the drilling and line production materials of the "L2--L9, L12-19" layers and the line materials of the L10-11 layers are increased to ensure that the expansion and shrinkage of each inner layer board is consistent in the second press, and the requirements of no offset between the layers are met.
[0026] Compared with the prior art, the manufacturing method of the twenty-layer three-step buried first-step blind via back-drilled HDI board provided by the present invention adopts a hierarchical manufacturing method to reduce the number of back drilling times, avoid back drilling to the circuit that cannot be avoided, and at the same time ensure the copper thickness requirements of the inner layer blind vias. In addition, through three times of pressing, on the one hand, the production of inner layer buried vias can be realized, and on the other hand, it is convenient to make blind vias of each layer, and solve the technical problems such as blind via copper plating core, copper plating and substrate copper not contacting, thin / uneven copper, and depression. For the secondary outer layer micro-via buried vias, the micro-via design can achieve very high path density with fewer layers, reduce the overall size, improve the benefits of assembly, space utilization, etc., and realize high-density interconnection. Interconnection is achieved through conductive through holes, buried vias and blind vias, which is different from ordinary multi-layer circuit boards in structure, and a large number of micro-buried blind vias, laser drilling, hole filling electroplating and other advanced technologies are used in the secondary product to achieve interconnection density, so that its electrical performance and signal correctness are higher than traditional PCBs.
[0027] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modification, equivalent substitution or improvement within the spirit of the present invention is included in the scope of the claims of the present invention.
Claims
1. A method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board, comprising the following steps: STEP101: Cutting - inner layer circuit - inner layer acid etching - AOI - browning - first pressing L2-9 - drilling - plasma - PTH - copper - resin plugging - circuit - AOI - browning; STEP102: Cutting--Inner layer circuit--Inner layer acid etching--AOI--Brown--Second lamination L12-19--Drilling--Plasma--PTH--One copper--Resin plugging--Circuit--AOI--Brown; STEP103: Press L2-L19 for the second time; STEP104: copper reduction--L2-19 layer drilling--plasma--PTH--board electricity--resin plugging--copper reduction--circuit / etching--third pressing, that is, pressing L2-L9 with L12 to L19 together; STEP105: Transfer to outer layer production: copper reduction after lamination -- L1-2, L19-20 layer laser drilling -- plasma -- filling plating -- copper reduction -- drilling -- plasma -- PTH -- pulse plating -- outer layer circuit -- graphic plating -- etching -- AOI -- solder mask -- text -- tin spraying -- testing -- molding -- final inspection.
2. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: In step STEP 101 , the width of the L2 line is determined according to the average value of the measured expansion and contraction data of L2-L9.
3. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: In step STEP 102, the widths of the lines of the L10, L11, and L19 layers are determined according to the average value of the measured expansion and contraction data of L12-L19.
4. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: Before step STEP104, the copper thickness on the surface of the L2 and L19 layers is reduced to 17-23 um.
5. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: In step STEP 104 , the copper thickness in the copper hole is reduced to 35-40 um.
6. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: During the first, second and third pressing, the pressing heating rate is controlled within the range of 2.0±0.5℃ / min, the temperature of the pressed material is controlled within the range of 80-140℃, the maximum pressure is 420PSI, and when the temperature of the outer layer material is between 80-100℃, high pressure is applied. The curing temperature should be greater than or equal to 195℃, and the curing time should be greater than or equal to 60min.
7. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: Silicone pad-type pressing is used in the first, second and third pressing to make the board thickness more uniform. The thickness of the dielectric layer of the second outer layer, i.e., the L1-L2 and L19-L20 layers, is controlled to 0.1mm±10%.
8. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: During the third pressing, the pressed layers L2-L9 and L12-L19 should be riveted first. The riveting is done by first using a high-precision electromagnetic hot melt machine to rivet the stacked layers together, and then using rivets for secondary reinforcement to prevent sliding or offset during the hot pressing process.
9. The method for manufacturing an ultra-high-rise three-level buried first-level blind via back-drilled HDI board according to claim 1, characterized in that: During drilling, the center of the hole pad is hollowed out by etching in the inner layer design to reduce the copper thickness.