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CN-121986551-A - Method for manufacturing printed circuit board

CN121986551ACN 121986551 ACN121986551 ACN 121986551ACN-121986551-A

Abstract

The invention relates to a method for producing printed circuit boards, comprising a continuous supply of a sheet of electrically conductive material (1), a continuous coating of at least one layer of electrically insulating material (2) on at least one region of one side surface of the sheet of electrically conductive material, the at least one layer of electrically insulating material (2) comprising at least one epoxy resin, a continuous photopolymerisation of at least part of the region of the epoxy resin under ultraviolet radiation, and a formation of at least one pattern in the sheet of electrically conductive material by means of photolithographic etching, the pattern being supported by the photopolymerised epoxy resin.

Inventors

  • Patrice Grace
  • JIATING HE
  • Sebastian Germain

Assignees

  • 兰克森控股公司

Dates

Publication Date
20260505
Application Date
20240925
Priority Date
20230927

Claims (18)

  1. 1. A method of manufacturing a printed circuit board, comprising the steps of: Continuously feeding a sheet (1) of electrically conductive material; continuously applying at least one layer of an electrically insulating material (2) on at least one region of a side surface of the sheet of electrically conductive material (1), the electrically insulating material (2) comprising at least one epoxy resin; continuously photopolymerizing at least a portion of the region of the epoxy resin under ultraviolet radiation, and At least one pattern is formed in the sheet (1) of conductive material by means of a photolithographic etch, said pattern being supported by the photopolymerizable epoxy resin.
  2. 2. The method of claim 1, wherein the pattern is an electrode configured for use in a medical/biological detection device.
  3. 3. A method according to claim 1 or 2, wherein the epoxy resin has a dry weight ratio of 30% to 70% in the insulating material layer applied to one side surface of the sheet of conductive material (1).
  4. 4. The method according to any of the preceding claims, wherein the insulating material layer (2) applied to one side surface of the sheet of conductive material (1) comprises a mineral filler in a dry weight ratio of 10% to 70%.
  5. 5. The method according to claim 4, wherein the inorganic filler consists essentially of glass microspheres (7).
  6. 6. The method of any of the preceding claims, wherein the epoxy resin is selected from cycloaliphatic epoxy resins that are polymerizable by ultraviolet light.
  7. 7. The method of claim 6 wherein the epoxy resin is selected from the group consisting of 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexylformate and bis (3, 4-epoxycyclohexylmethyl) adipate.
  8. 8. The method of any one of the preceding claims, wherein the layer of electrically insulating material comprises at least one photoinitiator.
  9. 9. The method of claim 8, wherein the photoinitiator is a cationic photoinitiator.
  10. 10. The method of claim 9, wherein the photoinitiator is bis (4, 4' - (C10-C13) -alkylphenyl) iodonium hexafluoroantimonate, or propylene carbonate.
  11. 11. The method according to any one of the preceding claims, wherein the layer of electrically insulating material (2) comprises a photopolymerisation kinetic modifier.
  12. 12. The method of claim 11, wherein the photopolymerisation kinetic modulator is phenothiazine.
  13. 13. The method according to any one of the preceding claims, wherein the layer of electrically insulating material (2) comprises at least one rheological agent.
  14. 14. The method of claim 13 wherein the rheological agent is selected from the group consisting of silicones, siloxanes, fumed silica.
  15. 15. A method according to any one of the preceding claims, wherein the thickness of the layer of electrically insulating material (2) is 50 to 350 microns.
  16. 16. The method of any of the preceding claims, further comprising the step of incubating at least a partial region of the sheet of conductive material supporting the photopolymerizable epoxy resin under ultraviolet radiation for not less than 1 hour at ambient temperature.
  17. 17. The method of claim 16, wherein the incubating step is performed immediately after the step of continuously performing the epoxy partial region photopolymerization for a duration of 1 hour to 12 hours.
  18. 18. The method according to any one of the preceding claims, wherein the step of continuously performing the partial region photopolymerization of the epoxy resin under ultraviolet radiation is performed under the condition that ultraviolet radiation emitted by the light emitting diode and having a radiation energy density of 60 to 140mW/cm2 is irradiated for 5 seconds to 5 minutes.

Description

Method for manufacturing printed circuit board Technical Field The invention relates to the field of printed circuit boards, in particular to a manufacturing method of a printed circuit board. For example, the present invention relates to the field of flexible printed circuit boards for medical/biological detection devices. Background Some printed circuit boards are made of a multi-layer structure comprising at least one sheet of conductive material laminated to a layer of electrically insulating material. The sheet of conductive material is used to form conductive patterns (conductive traces, contacts, antennas, electrodes, etc.). The layer of electrically insulating material serves as a support and a dielectric substrate. For example, the sheet of conductive material is made of a metal or metal alloy, which may be selected from one or more of copper, aluminum, copper alloys, aluminum alloys, steel, and the like. For example, the layer of electrically insulating material forms a dielectric substrate of glass-epoxy, polyimide, or polyethylene terephthalate, or the like. Alternatively, a layer of adhesive material may be used to adhere the sheet of conductive material to the layer of electrically insulating material. For example, the adhesive material layer is made of epoxy resin. Defects can be created at the interface between layers by laminating a sheet of electrically conductive material with an electrically insulating material, possibly with a layer of adhesive material disposed therebetween. An example of such a defect is shown in fig. 1. Fig. 1 shows a pattern 1 etched in a copper alloy sheet laminated on a dielectric substrate 2 (in this example, the dielectric substrate 2 is formed of a polyethylene terephthalate layer). Holes and/or channels 3 are present in the surface of the dielectric substrate 2. After lamination of the sheet of electrically conductive material with the layer of electrically insulating material and etching of the pattern 1 in the sheet of electrically conductive material, the holes and/or channels 3 form openings 4 at the edges of the pattern 1. More specifically, these openings 4 may form entry points for etching solutions used to form the pattern 1 in the sheet of conductive material by chemical or electrochemical etching. This may result in uncontrolled etching of the sheet of conductive material around the periphery of the pattern 1. Fig. 2 shows the situation where it can be seen that at the interface between the sheet of conductive material and the layer of dielectric material 2, the openings 4 formed at the edges of the pattern 1 result in etched cavities 5 being formed in the sheet of conductive material, even though there is an adhesive layer 6 between the sheet of conductive material and the layer of dielectric material. Such uncontrolled etching may create a number of disadvantages. This is particularly the case when using these multilayer structures for the manufacture Of electrodes for medical/biological detection devices, in particular for Point Of Care (POC) devices. The electrodes are used to detect one or more molecules in a fluid, including a body fluid of a human, and optionally to measure the concentration of these molecules. The detection and possibly concentration measurement is performed electrochemically, i.e. by immersing one or more electrodes made of the above-described multilayer structure in the fluid. The fluid may contain one or more reagents for reacting with the electrode and producing an electrical signal representing information about the nature and/or composition of the electrode. However, it has been found that the measurement results of the above-described electrodes are not always stable and/or repeatable. The applicant has studied this and determined that the presence of openings 4 (as shown in figures 1 and 2) at the interface between the layers may alter the response of these electrodes. Disclosure of Invention The object of the present invention is to at least partially overcome the above-mentioned drawbacks. For this purpose, a method for producing a printed circuit board is proposed. The printed circuit board is preferably flexible enough so that the method of the invention can be implemented in a continuous manner (roll-to-roll). The method according to the invention comprises the following steps: Continuously feeding a sheet of electrically conductive material, the sheet having two major surfaces; Continuously applying at least one layer of an electrically insulating material comprising at least one epoxy resin on at least one region of one of the major surfaces of the sheet of electrically conductive material; continuously photopolymerizing at least a portion of the epoxy resin (i.e., at least the area where the pattern is to be formed); At least one pattern is formed in the sheet of conductive material by photolithographic etching, the pattern being supported only by the photopolymerizable epoxy resin. Thus, by the method of the