CN117425290A - Precise circuit board with high heat dissipation performance and manufacturing method thereof - Google Patents

Abstract

The invention discloses a precise circuit board with high heat dissipation performance and a manufacturing method thereof, wherein the manufacturing method comprises the following steps: cutting a multi-layer copper foil with three copper foil layers, wherein a nickel layer is arranged between two adjacent copper foil layers; pasting dry films on two surfaces of the multilayer copper foil, and then windowing at positions corresponding to the circuit patterns on the dry films to manufacture a plurality of blind holes; performing hole filling electroplating on the multi-layer copper foil to form copper columns in the blind holes by electroplating, and removing the film; laminating the multilayer copper foil and PP, and exposing the top surface of the copper column through a grinding plate; peeling off the multi-layer copper foil, and removing the middle copper foil layer to form an upper production plate and a lower production plate; etching after the PP surface film in the production plate is stuck, and removing the copper foil layer on the other surface of the PP; after film stripping, depositing a copper layer on two surfaces of the PP through copper deposition, and manufacturing an outer layer circuit on the two surfaces of the PP through a positive film process. The method solves the problem that the precision circuit board cannot be manufactured by using the conventional copper/silver paste plug holes so as to meet the heat dissipation requirement.

Description

Precise circuit board with high heat dissipation performance and manufacturing method thereof

Technical Field

The invention relates to the technical field of printed circuit board manufacturing, in particular to a precise circuit board with high heat dissipation performance and a manufacturing method thereof.

Background

For the double-sided board with low reliability requirement, the hole plugging can be directly carried out by utilizing good conductive heat dissipation performance of copper paste and silver paste, and then a metal layer is plated on the surface of the copper paste or the silver paste, so that interlayer conduction is realized. For the multilayer board, copper paste plug holes or silver paste plug holes are needed to be made after in-hole electroplating, so that the electrical interconnection performance of the inner layer is ensured.

The simple double-panel copper/silver paste process flow comprises the following steps: drilling, plugging copper/silver paste, grinding a plate, forming an outer layer circuit, resisting welding, surface treatment and post-process

The process flow of the copper/silver paste of the inner layer buried orifice plate comprises the following steps: drilling, plugging copper/silver paste, grinding a plate, depositing copper, plating electricity, transferring patterns, etching, browning, pressing and carrying out post-process.

The printed board has the advantages that along with miniaturization, high density and multifunction of electronic equipment, the mounting density of components is greatly improved, so that the heat loss on the assembly area is increased, the conductive heat dissipation performance of copper/silver paste is conventionally utilized to directly plug holes, and the heat loss of the printed board can be reduced; in addition, for precision circuit manufacture, based on the capability of drilling equipment and in order to avoid circuit short circuit, the drilling aperture of 100 μm reaches the limit, the control difficulty is extremely high, the drilling cost is extremely high, the quality problems such as short circuit in broken holes and the like are extremely easy to occur, meanwhile, the distance from different network holes to the holes is more than 180 μm, the precision circuit board below the range cannot dissipate heat through the copper/silver paste plug hole manufacture after drilling, and the copper/silver paste plug hole production cost is high.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a manufacturing method of a precision circuit board with high heat dissipation performance, which can manufacture a high-precision circuit with a plurality of copper columns in a circuit area so as to meet the high heat dissipation performance of the precision circuit board and solve the problem that the precision circuit board cannot be manufactured by using a conventional copper/silver paste plug hole so as to meet the heat dissipation.

In order to solve the technical problems, the invention provides a manufacturing method of a precision circuit board with high heat dissipation performance, which comprises the following steps:

in a first aspect, the invention discloses a method for manufacturing a precision circuit board with high heat dissipation performance, comprising the following steps:

s1, cutting a multi-layer copper foil, wherein the multi-layer copper foil consists of a first copper foil layer, a second copper foil layer and a third copper foil layer which are sequentially arranged, and a nickel layer is arranged between two adjacent copper foil layers so as to separate the two adjacent copper foil layers;

s2, pasting dry films on two surfaces of the multilayer copper foil, and then windowing at positions corresponding to circuit patterns on the dry films sequentially through exposure and development to manufacture a plurality of blind holes exposing the copper surface of the inner layer;

s3, performing hole filling electroplating on the multi-layer copper foil to form copper columns in the blind holes by electroplating, and then removing the film;

s4, laminating PP on two surfaces of the multilayer copper foil, and enabling the top surfaces of the copper columns to be exposed through a grinding plate;

s5, stripping three copper foil layers of the multi-layer copper foil to remove a second copper foil layer in the middle, so as to form an upper independent production plate and a lower independent production plate;

s6, sticking a film on the surface of the PP in the production plate, and then etching to remove the copper foil layer on the other surface of the PP;

and S7, after film stripping, depositing a copper layer on two surfaces of the PP through copper deposition, and then manufacturing an outer layer circuit on the two surfaces of the PP through a positive process, wherein the pattern electroplating process in the positive process only comprises copper plating and tin plating.

Further, in step S1, the thicknesses of the first copper foil layer and the third copper foil layer are 3 μm, and the thickness of the second copper foil layer is 18 μm.

Further, in step S2, the thickness of the dry film is 200-300 μm, and the aperture of the blind hole is 100 μm.

Further, in step S3, the height of the copper pillar is lower than the thickness of the dry film.

Further, in step S4, excess PP is removed by a ceramic grinding plate to expose the top surface of the copper pillar.

In step S6, after the film is adhered to the PP surface, the exposed copper pillars are protected by the film, and then the exposed copper pillars are rapidly etched to remove the first copper foil layer or the third copper foil layer on the other surface of the PP, so as to manufacture a PP substrate with a plurality of copper pillars.

Further, in step S7, after copper layers are deposited on two surfaces of the PP substrate by copper deposition, a film is then attached to the PP substrate, and a circuit pattern is formed by exposure and development in sequence, copper columns are located in the circuit pattern area, the thickness of the copper layer at the circuit pattern is thickened by pattern electroplating, only copper is plated without tin during pattern electroplating, the plate surface copper layer at the non-circuit pattern is removed by rapid etching after film removal, and a high-heat-dissipation precise circuit with a plurality of copper columns is manufactured.

Further, in step S7, the copper layer deposited in the copper deposition step can have a thickness of 0.5. Mu.m.

In a second aspect, the invention also discloses a method for manufacturing the precision circuit board with high heat dissipation performance, which comprises the following steps:

s1, cutting a plurality of layers of copper foil, wherein the plurality of layers of copper foil consists of a first copper foil layer and a second copper foil layer which are sequentially arranged, and a nickel layer is arranged between the first copper foil layer and the second copper foil layer so as to separate the first copper foil layer and the second copper foil layer; the thickness of the first copper foil layer is 3 μm, and the thickness of the second copper foil layer is 18 μm

S2, pasting a dry film on the surface of the first copper foil layer, and then windowing at the position corresponding to the circuit pattern on the dry film sequentially through exposure and development to manufacture a plurality of blind holes exposing the surface of the first copper foil layer; and the surface of the second copper foil layer is stuck with a full exposure dry film protection;

s3, performing hole filling electroplating on the multi-layer copper foil to form copper columns in the blind holes by electroplating, and then removing the film;

s4, laminating PP on the surface of the first copper foil layer, and then laminating, wherein the top surface of the copper column is exposed through a grinding plate;

s5, stripping the two copper foil layers of the multi-layer copper foil, removing the second copper foil layer, and reserving the first copper foil layer with PP to form a production plate;

s6, sticking a film on the surface of the PP in the production plate, and then etching to remove the first copper foil layer on the other surface of the PP;

and S7, after film stripping, depositing a copper layer on two surfaces of the PP through copper deposition, and then manufacturing an outer layer circuit on the two surfaces of the PP through a positive process, wherein the pattern electroplating process in the positive process only comprises copper plating and tin plating.

In a third aspect, the present invention also discloses a precision circuit board with high heat dissipation performance, which is manufactured by the manufacturing method according to any one of the first aspect or the second aspect.

Further, the following steps are included between the steps S3 and S4:

s31, grinding the copper-clad plate to make the plate surface flat.

Compared with the prior art, the invention has the following beneficial effects:

in the invention, firstly, a copper column is formed after hole filling electroplating by pasting a dry film on a multilayer copper foil and windowing to form a plurality of blind holes, and the copper column is positioned in a circuit area for later heat dissipation, and because the hole diameter of a drilling hole of a copper/silver paste hole plugging process is more than 180 mu m, the conventional copper/silver paste hole plugging in the prior art cannot manufacture a high heat dissipation precision circuit board with the hole spacing less than or equal to 180 mu m, the space between holes can be less than or equal to 180 mu m by exposing and developing the blind holes to form the blind holes, the manufacturing requirement of the high heat dissipation precision circuit board with the hole spacing less than or equal to 180 mu m is met, the manufacturing process has small control difficulty, convenient manufacture and can effectively improve the production quality, the method solves the quality problems that the control difficulty is high, the cost is high and the circuit short circuit is easy to occur in the prior drilling mode, and because the adjacent copper foil layers of the multi-layer copper foil are separated by adopting nickel layers, and the characteristic that the nickel layers and the copper layers are combined and then stripped is utilized, the manufactured copper columns and PP form a whole after the copper foil layers on the surface of the PP are etched, the PP base material (equivalent to a core plate) manufactured by the circuit board is used, and outer-layer circuits are manufactured on the two surfaces of the PP in the modes of copper deposition and positive film technology.

Drawings

FIG. 1 is a schematic view of a multi-layered copper foil of example 1;

FIG. 2 is a schematic diagram of example 1 after dry film is applied to a multi-layered copper foil and electroplated to form copper posts;

FIG. 3 is a schematic view of example 1 after forming copper pillars on the multi-layered copper foil and removing the dry film;

FIG. 4 is a schematic diagram of the laminated copper foil and PP film of example 1;

FIG. 5 is a schematic view of the multilayer copper foil of example 1 after being peeled;

FIG. 6 is a schematic view of the multi-layered copper foil of example 1 after removal of the second copper foil layer;

FIG. 7 is a schematic diagram of example 1 after dry film application to a production board;

fig. 8 is a schematic diagram of the production board of example 1 after etching away the copper foil layer to form a PP substrate.

Detailed Description

In order to more fully understand the technical content of the present invention, the technical solution of the present invention will be further described and illustrated with reference to specific embodiments.

Example 1

The manufacturing method of the precise circuit board with high heat dissipation performance comprises the following processing procedures in sequence:

(1) Cutting: preparing a plurality of layers of copper foil and cutting according to the design size, wherein the plurality of layers of copper foil comprises a first copper foil layer 1, a second copper foil layer 2 and a third copper foil layer 3 which are sequentially arranged, and a nickel layer (not shown in the figure) is arranged between two adjacent copper foil layers so as to separate the two adjacent copper foil layers; the thickness of the first copper foil layer and the third copper foil layer is 3 μm, the thickness of the second copper foil layer is 18 μm, and the thickness of the nickel layer is generally controlled to be 0.5 μm.

(2) Sticking film: as shown in fig. 2, dry films 4 are attached to two surfaces of the multi-layer copper foil, and then windows are formed at positions corresponding to circuit patterns on the dry films through exposure and development in sequence, so that a plurality of blind holes 5 exposing the copper surface of the inner layer are formed at positions corresponding to the circuit patterns.

In the above, the thickness of the dry film is 200-300 μm, and the aperture of the blind hole is 100 μm.

(3) Hole filling electroplating: the multi-layered copper foil is subjected to hole filling plating to form copper pillars 6 (as shown in fig. 2) in the blind holes by electroplating, and then film is backed (as shown in fig. 3).

Among the above, the copper post highly is less than the thickness of dry film, avoids the copper post top after electroplating to surpass behind the dry film radial expansion, and then surpasses the regional etching operation and the circuit quality of later stage of influence of circuit figure.

(4) Pressing: as shown in fig. 4, after PP7 is laminated on two surfaces of the multi-layer copper foil, only PP is laminated, and then the redundant PP on the two surfaces is removed by a ceramic grinding plate, so that the top surface of the copper pillar is exposed, i.e. the top surface of the copper pillar is flush with the surface of PP.

(5) Stripping: as shown in fig. 5, three copper foil layers of the multi-layered copper foil are peeled off from each other to remove the second copper foil layer in the middle, thereby forming two independent production boards (as shown in fig. 6), i.e., one production board formed by combining the first copper foil layer with PP and the other production board formed by combining the third copper foil layer with PP.

(6) Etching: as shown in fig. 7, a dry film 4 is attached to the surface of one side of PP in the production board, then a full-face exposure is performed to protect the exposed copper pillars by the dry film, then a rapid etching is performed to remove the first copper foil layer or the third copper foil layer on the other surface of PP, so as to manufacture a PP substrate with a plurality of copper pillars (namely, equivalent to manufacturing a core board of a circuit board), and then film stripping is performed (as shown in fig. 8).

(7) Copper deposition: and depositing a copper layer with the thickness of 0.5 mu m on both surfaces of the PP substrate through a copper deposition process.

(8) And (3) manufacturing an outer layer circuit: transferring the outer layer pattern, completing outer layer line exposure by using an LDI exposure machine with a 5-7-grid exposure rule (a 21-grid exposure rule), developing to form an outer layer line pattern on the PP substrate, and positioning copper columns in the line pattern area; plating the outer layer pattern, plating copper on the production board, and plating the copper layer at the outer layer circuit pattern to the thickness required by design, wherein the copper is plated only without plating the tin during pattern plating; removing the plate surface copper layer of the non-outer layer circuit part by rapid etching after film stripping to prepare a high-heat-dissipation precise circuit with a plurality of copper columns inside; an outer layer AOI, which uses an automatic optical detection system to detect whether the outer layer circuit has defects such as open circuit, notch, incomplete etching, short circuit, etc. by comparing with CAM data

(9) And the subsequent steps of manufacturing a solder mask layer, surface treatment, forming treatment and FQC detection on the PP substrate in sequence to obtain the precise circuit board with high heat dissipation performance.

Example 2

The manufacturing method of the precise circuit board with high heat dissipation performance comprises the following processing procedures in sequence:

(1) Cutting: preparing a plurality of layers of copper foil, and cutting according to the design size, wherein the plurality of layers of copper foil consists of a first copper foil layer and a second copper foil layer which are sequentially arranged, and a nickel layer is arranged between the first copper foil layer and the second copper foil layer so as to separate the first copper foil layer and the second copper foil layer; the thickness of the first copper foil layer is 3 μm, the thickness of the second copper foil layer is 18 μm, and the thickness of the nickel layer is generally controlled to be 0.5 μm.

(2) Sticking film: pasting a dry film on the surface of the first copper foil layer, and then windowing at the position corresponding to the circuit pattern on the dry film sequentially through exposure and development to manufacture a plurality of blind holes exposing the copper surface of the inner layer at the position corresponding to the circuit pattern; meanwhile, a dry film is also stuck on the surface of the second copper foil layer, but the dry film on the second copper foil layer is exposed to full exposure to protect the whole second copper foil layer.

In the above, the thickness of the dry film is 200-300 μm, and the aperture of the blind hole is 100 μm.

(4) Hole filling electroplating: and (3) performing hole filling electroplating on the multi-layer copper foil to form copper columns in the blind holes by electroplating, and then carrying out film backing.

Among the above, the copper post highly is less than the thickness of dry film, avoids the copper post top after electroplating to surpass behind the dry film radial expansion, and then surpasses the regional etching operation and the circuit quality of later stage of influence of circuit figure.

(4) Pressing: and laminating PP on the surface of the first copper foil layer, laminating the PP, removing redundant PP through a ceramic grinding plate, and exposing the top surface of the copper column, namely, enabling the top surface of the copper column to be flush with the surface of the PP.

(5) Stripping: and stripping the first copper foil layer and the second copper foil layer, removing the second copper foil layer, and reserving the first copper foil layer with PP to form the production plate.

(6) Etching: and (3) pasting a dry film on the surface of one side of the PP in the production board, performing surface finishing exposure to protect the exposed copper columns through the dry film, performing rapid etching to remove a first copper foil layer on the other surface of the PP, manufacturing a PP base material (namely, a core board equivalent to manufacturing a circuit board) with a plurality of copper columns, and removing the film.

(7) Copper deposition: and depositing a copper layer with the thickness of 0.5 mu m on both surfaces of the PP substrate through a copper deposition process.

(8) And (3) manufacturing an outer layer circuit: transferring the outer layer pattern, completing outer layer line exposure by using an LDI exposure machine with a 5-7-grid exposure rule (a 21-grid exposure rule), developing to form an outer layer line pattern on the PP substrate, and positioning copper columns in the line pattern area; plating the outer layer pattern, plating copper on the production board, and plating the copper layer at the outer layer circuit pattern to the thickness required by design, wherein the copper is plated only without plating the tin during pattern plating; removing the plate surface copper layer of the non-outer layer circuit part by rapid etching after film stripping to prepare a high-heat-dissipation precise circuit with a plurality of copper columns inside; the outer layer AO I uses an automatic optical detection system to detect whether the outer layer circuit has defects such as open circuit, notch, incomplete etching, short circuit, etc. by comparing with CAM data

(9) And the subsequent steps of manufacturing a solder mask layer, surface treatment, forming treatment and FQC detection on the PP substrate in sequence to obtain the precise circuit board with high heat dissipation performance.

The foregoing has described in detail the technical solutions provided by the embodiments of the present invention, and specific examples have been applied to illustrate the principles and implementations of the embodiments of the present invention, where the above description of the embodiments is only suitable for helping to understand the principles of the embodiments of the present invention; meanwhile, as for those skilled in the art, according to the embodiments of the present invention, there are variations in the specific embodiments and the application scope, and the present description should not be construed as limiting the present invention.

Claims (10)

1. The manufacturing method of the precise circuit board with high heat dissipation performance is characterized by comprising the following steps of:

s1, cutting a multi-layer copper foil, wherein the multi-layer copper foil consists of a first copper foil layer, a second copper foil layer and a third copper foil layer which are sequentially arranged, and a nickel layer is arranged between two adjacent copper foil layers so as to separate the two adjacent copper foil layers;

s2, pasting dry films on two surfaces of the multilayer copper foil, and then windowing at positions corresponding to circuit patterns on the dry films sequentially through exposure and development to manufacture a plurality of blind holes exposing the copper surface of the inner layer;

s3, performing hole filling electroplating on the multi-layer copper foil to form copper columns in the blind holes by electroplating, and then removing the film;

s4, laminating PP on two surfaces of the multilayer copper foil, and enabling the top surfaces of the copper columns to be exposed through a grinding plate;

s5, stripping three copper foil layers of the multi-layer copper foil to remove a second copper foil layer in the middle, so as to form an upper independent production plate and a lower independent production plate;

s6, sticking a film on the surface of the PP in the production plate, and then etching to remove the copper foil layer on the other surface of the PP;

and S7, after film stripping, depositing a copper layer on two surfaces of the PP through copper deposition, and then manufacturing an outer layer circuit on the two surfaces of the PP through a positive process, wherein the pattern electroplating process in the positive process only comprises copper plating and tin plating.

2. The method of manufacturing a precision circuit board with high heat dissipation performance according to claim 1, wherein in step S1, the thicknesses of the first copper foil layer and the third copper foil layer are 3 μm, and the thickness of the second copper foil layer is 18 μm.

3. The method of manufacturing a precision circuit board with high heat dissipation performance according to claim 1, wherein in step S2, the thickness of the dry film is 200-300 μm, and the aperture of the blind hole is 100 μm.

4. The method of manufacturing a precision circuit board with high heat dissipation performance according to any one of claims 1 to 3, wherein in step S3, the height of the copper pillar is lower than the thickness of the dry film.

5. The method of manufacturing a precision circuit board with high heat dissipation performance according to claim 1, wherein in step S4, excess PP is removed by a ceramic grinding plate to expose the top surface of the copper pillar.

6. The method for manufacturing a precision circuit board with high heat dissipation performance according to claim 1, wherein in step S6, after the surface of PP is coated with a film, the exposed copper pillars are protected by the film, and then the exposed copper pillars are rapidly etched to remove the first copper foil layer or the third copper foil layer on the other surface of PP, so as to manufacture a PP substrate with a plurality of copper pillars.

7. The method for manufacturing a precision circuit board with high heat dissipation performance according to claim 6, wherein in step S7, after copper layers are deposited on two surfaces of a PP substrate by copper deposition, a film is then pasted on the PP substrate, a circuit pattern is formed by exposure and development in sequence, copper columns are located in the circuit pattern area, the thickness of the copper layer at the circuit pattern is thickened by pattern electroplating, only copper plating is performed during pattern electroplating without tin plating, and after film removal, a plate surface copper layer at a non-circuit pattern is removed by rapid etching, so that a high heat dissipation precision circuit with a plurality of copper columns is manufactured.

8. The method of manufacturing a precision circuit board with high heat dissipation performance according to claim 1, wherein in step S7, the thickness of the copper layer deposited in the copper deposition step is 0.5 μm.

9. The manufacturing method of the precise circuit board with high heat dissipation performance is characterized by comprising the following steps of:

s1, cutting a plurality of layers of copper foil, wherein the plurality of layers of copper foil consists of a first copper foil layer and a second copper foil layer which are sequentially arranged, and a nickel layer is arranged between the first copper foil layer and the second copper foil layer so as to separate the first copper foil layer and the second copper foil layer; the thickness of the first copper foil layer is 3 μm, and the thickness of the second copper foil layer is 18 μm

S2, pasting a dry film on the surface of the first copper foil layer, and then windowing at the position corresponding to the circuit pattern on the dry film sequentially through exposure and development to manufacture a plurality of blind holes exposing the surface of the first copper foil layer; and the surface of the second copper foil layer is stuck with a full exposure dry film protection;

s3, performing hole filling electroplating on the multi-layer copper foil to form copper columns in the blind holes by electroplating, and then removing the film;

s4, laminating PP on the surface of the first copper foil layer, and then laminating, wherein the top surface of the copper column is exposed through a grinding plate;

s5, stripping the two copper foil layers of the multi-layer copper foil, removing the second copper foil layer, and reserving the first copper foil layer with PP to form a production plate;

s6, sticking a film on the surface of the PP in the production plate, and then etching to remove the first copper foil layer on the other surface of the PP;

and S7, after film stripping, depositing a copper layer on two surfaces of the PP through copper deposition, and then manufacturing an outer layer circuit on the two surfaces of the PP through a positive process, wherein the pattern electroplating process in the positive process only comprises copper plating and tin plating.

10. A precision circuit board having high heat dissipation properties, characterized in that it is manufactured by the manufacturing method according to any one of claims 1 to 9.