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CN-122028334-A - Preparation method of high-heat-conductivity thick copper coil circuit board

CN122028334ACN 122028334 ACN122028334 ACN 122028334ACN-122028334-A

Abstract

The invention relates to the technical field of printed circuit board manufacturing, in particular to a preparation method of a high-heat-conductivity thick copper coil circuit board, which comprises the following steps of S1 mixing a heat-conducting filler with cyanate resin to form a modified heat-conducting adhesive film, S2 carrying out surface treatment on a thick copper foil to obtain a surface-modified micro-nano composite thick copper foil, S3 carrying out lamination according to the alternating sequence of a conductive layer and an insulating adhesive layer to form a multi-layer pre-lamination structure, S4 carrying out a gradient hot-pressing process to obtain a composite substrate, S5 carrying out annealing treatment on the composite substrate of S4 to obtain a stable composite substrate, S6 forming an etching-resistant pattern on the surface of the stable composite substrate of S5, and S7 carrying out post treatment to obtain a finished product of the high-heat-conductivity thick copper coil circuit board. According to the invention, the thick copper coil circuit board with high heat conduction, high bonding strength and low internal stress is prepared through the synergistic process of material modification, interface construction, gradient hot pressing and stress release.

Inventors

  • LI GUOBIN
  • LAI LIRONG
  • Xu Tengfang

Assignees

  • 启绩科技(广东)有限公司

Dates

Publication Date
20260512
Application Date
20260402

Claims (9)

  1. 1. The preparation method of the high-heat-conductivity thick copper coil circuit board is characterized by comprising the following steps of: S1, mixing a heat conducting filler with cyanate resin, and coating to form a modified heat conducting adhesive film after vacuum stirring and defoaming; s2, carrying out surface treatment on the thick copper foil, firstly forming a roughened layer on the surface of the thick copper foil, and then depositing a nano composite coating on the surface of the roughened layer to obtain a surface-modified micro-nano composite thick copper foil; S3, taking the micro-nano composite thick copper foil of S2 as a conductive layer, taking the modified heat-conducting adhesive film of S1 as an insulating adhesive layer, laminating the conductive layer and the insulating adhesive layer in an alternating sequence, and pre-fixing the conductive layer and the insulating adhesive layer in a local hot-press spot welding mode to form a multi-layer pre-lamination structure; s4, placing the multi-layer pre-stacked structure formed in the S3 in a vacuum hot press, performing a gradient hot pressing process, and sequentially performing press fit solidification through a low-temperature low-pressure stage and a high-temperature high-pressure stage to obtain a composite substrate; S5, annealing the composite substrate of the S4, and then cooling to obtain a stable composite substrate after stress release; s6, forming an etching-resistant pattern on the surface of the stable composite substrate in the S5, and etching the thick copper layer in the uncovered area to form a thick copper coil circuit board semi-finished product with a preset circuit pattern; And S7, carrying out post-treatment on the circuit pattern surface of the semi-finished product of the S6 thick copper coil circuit board, and finally obtaining the finished product of the high-heat-conductivity thick copper coil circuit board.
  2. 2. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the S1 specifically comprises: S11, respectively weighing the heat-conducting filler and the cyanate ester resin according to the weight ratio of 7:3, and adding a silane coupling agent accounting for 0.5% -2.0% of the total weight of the heat-conducting filler; S12, putting the heat conducting filler, the silane coupling agent and the cyanate ester resin into a stirring container, and premixing for 15-30 min under the condition that the rotating speed is 800-1200 rpm to obtain a primary mixed material; S13, transferring the preliminary mixed material into a vacuum stirring deaerator, stirring and deaerating for 30-60 min under the conditions of vacuum degree of-0.09 MPa to-0.1 MPa and rotating speed of 600rpm-1000rpm, and obtaining deaerated heat-conducting mucilage; And S14, coating the defoamed heat-conducting adhesive cement on a release film through a coating machine, and controlling the coating thickness to be 50-120 mu m to form a modified heat-conducting adhesive film.
  3. 3. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 2, wherein the thermal conductive filler is selected from spherical alumina or aluminum nitride, and the cyanate resin is selected from bisphenol a type cyanate resin or phenolic type cyanate resin.
  4. 4. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the step S2 specifically comprises: S21, preparing a rolled copper foil with the thickness of 210-420 mu m, and carrying out degreasing and pickling pretreatment on the surface of the rolled copper foil; S22, placing the pretreated rolled copper foil in an electroplating bath, and carrying out electrochemical deposition by adopting direct current with the current density of 15A/dm2-25A/dm2 for 30S-90S, wherein the plating solution is a copper sulfate system, and a needle-shaped roughened layer is formed on the surface of the copper foil; S23, immersing the copper foil after the needle-shaped roughened layer is formed in a deposition solution, wherein the deposition solution comprises 0.5g/L-1.5g/L of graphene oxide and 2g/L-4g/L of dopamine, the solvent is Tris buffer solution with the pH value of 8.0-8.5, the reaction is carried out for 30min-60min under the condition that the temperature is 40-50 ℃, and a graphene oxide-polydopamine composite coating is deposited on the surface of the needle-shaped roughened layer; and S24, taking out the copper foil deposited with the composite coating, flushing with deionized water, and drying at the temperature of 60-80 ℃ for 10-20 min to obtain the surface modified micro-nano composite thick copper foil.
  5. 5. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the step S3 specifically comprises: S31, providing two micro-nano composite thick copper foils prepared by S2 and one modified heat-conducting adhesive film prepared by S1, placing the modified heat-conducting adhesive film between the two micro-nano composite thick copper foils, and laminating the two micro-nano composite thick copper foils, the modified heat-conducting adhesive film and the micro-nano composite thick copper foils in sequence from top to bottom to align edges of each layer to form an initial laminated structure; S32, placing the initial laminated structure on a workbench of spot welding equipment, and carrying out local spot welding fixation by adopting a hot-press spot welding head in a preset non-line pattern area, wherein the spot welding temperature is 180-200 ℃, the spot welding pressure is 0.2-0.5 MPa, the single-point spot welding time is 1S-3S, and the pitch of spot welding lattices is 30-50 mm; and S33, after the welding of all the spot welding points is completed, obtaining the multi-layer pre-stacked structure.
  6. 6. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the step S4 specifically comprises: S41, placing the multi-layer pre-stacked structure prepared in the step S3 on a working platform of a vacuum hot press, closing the press, and vacuumizing a cavity to maintain the vacuum degree of the cavity below 10 Pa; s42, executing a low-temperature and low-pressure stage, and raising the temperature from room temperature to 120-130 ℃ at a temperature raising rate of 1.5-2.5 ℃ per minute, and raising the pressure to 0.5-1.0 MPa and keeping for 10-20 min; S43, executing a high-temperature and high-pressure stage, raising the temperature to 220-240 ℃ at a temperature raising rate of 2.0-3.0 ℃ per minute, raising the pressure to 3.5-5.0 MPa, and maintaining for 60-90 min; S44, cooling the temperature to room temperature at a cooling rate of 1.0-2.0 ℃ per minute under the condition of keeping the pressure to 3.5-5.0 MPa, then releasing pressure, starting the press, and taking out to obtain the composite substrate.
  7. 7. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the step S5 specifically comprises: s51, placing the composite substrate prepared in the step S4 in an oven, closing a door of the oven and introducing nitrogen, and raising the temperature in the oven from room temperature to 160-180 ℃ at a heating rate of 1.0-2.0 ℃ per minute; s52, keeping the temperature in the oven constant under the temperature condition of 160-180 ℃, and carrying out annealing treatment on the composite substrate for 4-6 hours; And S53, after the annealing treatment is finished, turning off a heating power supply of the oven, naturally cooling the composite substrate to room temperature in the oven, and taking out to obtain the stable composite substrate after stress release.
  8. 8. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the step S6 specifically comprises: S61, cleaning the surface of the stable composite substrate prepared in the step S5, spraying and cleaning for 2-5 min at the temperature of 40-50 ℃ by adopting an acid cleaning agent, and then washing with deionized water and drying; S62, adhering a photosensitive dry film on the surface of the cleaned stable composite substrate, wherein the film adhering temperature is 100-120 ℃, the film adhering pressure is 0.3-0.5 MPa, and the film adhering speed is 1.0-1.5 m/min; S63, placing the substrate subjected to film pasting in an exposure machine, and performing alignment exposure by adopting a photomask with a preset circuit pattern, wherein the exposure energy is 80mJ/cm < 2 > -120mJ/cm < 2 >; S64, placing the exposed substrate in a developing solution, wherein the developing solution is 1.0% -1.5% of sodium carbonate aqueous solution, the developing temperature is 28-32 ℃, the developing time is 40-80S, removing the photosensitive dry film in the unexposed area, exposing the surface of the thick copper layer to be etched, and forming an etching-resistant pattern; S65, placing the developed substrate in an acid etching solution, controlling the temperature of the etching solution to be 50-55 ℃ and the spraying pressure to be 0.2-0.3 MPa, so that a thick copper layer which is not covered by the etching-resistant pattern is completely removed, and forming a preset circuit pattern; And S66, placing the etched substrate in film stripping liquid, wherein the film stripping liquid is 2.0% -3.0% of sodium hydroxide aqueous solution, the film stripping temperature is 45-55 ℃, the film stripping time is 60-120S, removing the photosensitive dry film on the surface of the circuit, and washing and drying the circuit by deionized water to obtain a thick copper coil circuit board semi-finished product.
  9. 9. The method for manufacturing a high thermal conductivity thick copper coil circuit board according to claim 1, wherein the step S7 specifically comprises: S71, placing the thick copper coil circuit board semi-finished product prepared in the S6 into a microetching tank, carrying out microetching roughening treatment by adopting sodium persulfate-sulfuric acid system microetching solution, wherein the concentration of sodium persulfate in the microetching solution is 80g/L-120g/L, the volume concentration of sulfuric acid is 3% -5%, the microetching temperature is 30-40 ℃, the microetching time is 60-120S, and the microetching depth is controlled to be 1-3 mu m; s72, carrying out overflow cleaning on the circuit board subjected to microetching coarsening by using deionized water for 2-5 min, and removing microetching liquid remained on the surface; S73, placing the cleaned circuit board in an organic solder mask coating groove, coating by adopting imidazole organic solder mask, wherein the concentration of the solder mask is 5% -10%, the coating temperature is 40-50 ℃, the coating time is 60-90S, and the thickness of the organic solder mask is controlled to be 0.2-0.5 mu m; S74, cleaning the circuit board coated with the organic solder mask by deionized water for 1-3 min to remove superfluous solder mask residues on the surface; And S75, placing the cleaned circuit board in an oven, and drying at the temperature of 80-100 ℃ for 10-20 min to obtain a finished product of the high-heat-conductivity thick copper coil circuit board.

Description

Preparation method of high-heat-conductivity thick copper coil circuit board Technical Field The invention relates to the technical field of printed circuit board manufacturing, in particular to a preparation method of a high-heat-conductivity thick copper coil circuit board. Background The thick copper coil circuit board is widely applied to the fields of high-power supply modules, new energy automobile electric control systems, high-power LED illumination and the like with severe requirements on thermal management due to the excellent current carrying capacity, in the circuit board, an insulating medium layer bears the dual functions of electric isolation and mechanical support, in the traditional preparation process, a common prepreg is generally adopted for the insulating medium layer, the heat conductivity is generally lower than 0.8W/m.K, the Joule heat generated by the thick copper coil is difficult to be rapidly LED out, hot spots are formed by local accumulation of the heat, the reliability and the power output capacity of electronic equipment are seriously influenced, and in order to improve the heat dissipation performance, the high heat conduction filler is partially tried to be added into resin in the prior art, but the problem of process fluidity and brittleness caused by the interface compatibility and the high filling amount of the filler is limited, and the heat conduction performance, the processing performance and the mechanical toughness are difficult to be considered. Meanwhile, the core problems faced in the manufacturing process of the thick copper circuit board are that the bonding reliability and internal stress control are achieved between the thick copper layer and the insulating medium layer, the difference of linear expansion coefficients of copper and insulating materials is remarkable, huge interlayer shearing stress is easy to generate in high-temperature lamination and subsequent thermal processing, chemical roughening or blackening treatment is mostly adopted in the prior art to increase mechanical anchoring force, but chemical bonding is difficult to form, long-term reliability is insufficient, the problems of foaming, layering and warping of the whole board are remarkable, in addition, the problem of side etching effect is remarkable in thick copper circuit etching, the line width control difficulty is high, and the manufacturing yield of the high-precision coil circuit board is further restricted. Therefore, there is a need to develop a method for manufacturing a high thermal conductivity thick copper coil circuit board to solve the above-mentioned technical problems. Disclosure of Invention Based on the above purpose, the invention provides a preparation method of the high-heat-conductivity thick copper coil circuit board. A preparation method of a high-heat-conductivity thick copper coil circuit board comprises the following steps: S1, mixing a heat conducting filler with cyanate resin, and coating to form a modified heat conducting adhesive film after vacuum stirring and defoaming; s2, carrying out surface treatment on the thick copper foil, firstly forming a roughened layer on the surface of the thick copper foil, and then depositing a nano composite coating on the surface of the roughened layer to obtain a surface-modified micro-nano composite thick copper foil; S3, taking the micro-nano composite thick copper foil of S2 as a conductive layer, taking the modified heat-conducting adhesive film of S1 as an insulating adhesive layer, laminating the conductive layer and the insulating adhesive layer in an alternating sequence, and pre-fixing the conductive layer and the insulating adhesive layer in a local hot-press spot welding mode to form a multi-layer pre-lamination structure; s4, placing the multi-layer pre-stacked structure formed in the S3 in a vacuum hot press, performing a gradient hot pressing process, and sequentially performing press fit solidification through a low-temperature low-pressure stage and a high-temperature high-pressure stage to obtain a composite substrate; S5, annealing the composite substrate of the S4, and then cooling to obtain a stable composite substrate after stress release; s6, forming an etching-resistant pattern on the surface of the stable composite substrate in the S5, and etching the thick copper layer in the uncovered area to form a thick copper coil circuit board semi-finished product with a preset circuit pattern; And S7, carrying out post-treatment on the circuit pattern surface of the semi-finished product of the S6 thick copper coil circuit board, and finally obtaining the finished product of the high-heat-conductivity thick copper coil circuit board. Optionally, the S1 specifically includes: S11, respectively weighing the heat-conducting filler and the cyanate ester resin according to the weight ratio of 7:3, and adding a silane coupling agent accounting for 0.5% -2.0% of the total weight of the heat-conducting filler; S12,