WO2004105451A1

WO2004105451A1 - Printed ciruit board and method of producing the same

Info

Publication number: WO2004105451A1
Application number: PCT/CN2004/000520
Authority: WO
Inventors: Lihua Wang
Original assignee: Lihua Wang
Priority date: 2003-05-26
Filing date: 2004-05-24
Publication date: 2004-12-02
Also published as: CN1553760A; CN1290384C

Abstract

The present invention discloses a printed circuit board having metal substrate, high heat dispersion and metallized hole, and method for manufacturing the same. The printed circuit board comprises metal substrate, double sided wiring layers on the surface of metal substrate and insulating film between wiring layers and metal substrate. There are holes disposed in the metal substrate of printed circuit board and metal layers on the inner surface of the holes. The double sided wiring layers on the surface of metal substrate are connected by the metal layers on the inner surface of the holes.

Description

Aluminum, magnesium or its alloy-based high-radiation-hole metallized printed wiring board and manufacturing method thereof

The present invention relates to a printed wiring board with electronic components installed in electronic and electrical equipment facility components and a method for manufacturing the same. More specifically, the present invention relates to an aluminum, magnesium or its alloy-based metallized printed wiring board with high heat dissipation holes. And its manufacturing method. Background technique

Existing circuit board plates can be divided into two categories, organic and inorganic, and organic plates can be divided into paper-based phenolic sheet, paper-based epoxy sheet, glass cloth phenolic sheet, glass cloth epoxy sheet, glass cloth polytetrafluoro Acetate sheet, carbon-based sheet, etc., inorganic sheet can be divided into ceramic-based sheet, metal-based sheet and so on. The metal-based plate is a plate made of copper or molybdenum powder metallurgy, or a plate made of aluminum-lithium mixed insulating powder, or a plate made of iron or stainless steel. After drilling, it is impregnated with a resin insulation layer or A ceramic insulating layer is fired, or an aluminum plate is anodized with sulfuric acid on the surface, and a copper-clad plate is made of an adhesive copper foil. Circuit boards made of existing organic circuit board materials have poor heat dissipation, poor bendability and flame retardancy; while inorganic circuit boards are used to prepare circuit boards, the processing process is complicated, the cost is high, and the weight is large. Although the copper clad board is light in weight, it cannot achieve metallization of small holes to interconnect circuit interconnections. At the same time, the coating layer also affects the heat dissipation effect. Summary of the Invention

One of the objectives of the present invention is to provide a printed circuit board made of metallic aluminum, metallic magnesium or its alloy sheet material, which has good heat dissipation and can realize metallization of single and double-sided circuits with small holes. This printed wiring board is particularly suitable for devices that generate heat and require heat dissipation when mounting components on the printed wiring board.

Another object of the present invention is to provide a method for manufacturing the above-mentioned printed wiring board.

Confirm this In one aspect, the present invention provides a metal substrate-based, high-heat-dissipation, hole-metallized printed circuit board. The printed circuit board includes a metal substrate, a double-sided circuit metal layer on a surface of the metal substrate, and An insulating film between the line metal layer and the metal substrate; the metal substrate is also perforated, and a hole wall metal layer is provided on the hole wall of the hole.

Preferably, the metal substrate of the printed wiring board is made of a metal aluminum plate, an aluminum alloy plate, a metal magnesium plate, a magnesium alloy plate, or a magnesium aluminum alloy plate; and the circuit metal layer and the hole wall metal layer are preferably copper layers. And / or a silver layer, more preferably a copper layer.

The insulating film of each of the printed wiring boards may be an oxide film, and the micropores on the insulating film contain a low-molecular organic substance or an organic glue that closes the micropores; the organic glue may be a low-viscosity anaerobic Glue, for example, organic monthly delivery whose main component is acrylic acid, methacrylic acid and / or its ester.

In the printed wiring board of the present invention, the circuit metal layer and the hole wall metal layer on the surface of the metal base material are patterns made according to the design, and the circuit metal layer uses the hole wall metal layer to realize circuit interaction on both sides of the metal substrate Connected.

On the other hand, the present invention also provides a method for manufacturing a hole-metallized printed wiring board with a metal substrate. The method includes the following steps:

(1) selecting an appropriate metal substrate and punching holes in the metal substrate;

(2) performing oxidation treatment on the metal substrate obtained after the punching in step (1) to form an insulating film;

(3) performing a sealing treatment on the plate-like product obtained in step (2) to close the micropores on the insulating film;

(4) forming a metal plating layer on the plate-like product obtained in step (3);

(5) performing filming, plate-making, developing, and pattern plating processing on the plate-like product characteristics obtained in step (4);

(6) The plate-like product obtained in step (5) is subjected to a plating resist and an etching treatment, and finally a desired printed wiring board is obtained. In the above step (1), the metal substrate may be selected from a metal aluminum plate, an aluminum alloy plate, a metal magnesium plate, a magnesium alloy plate, or a magnesium aluminum alloy plate.

In the above step (2), the so-called insulating film is an oxide film obtained by oxidation treatment; and the oxidation treatment method may be anodization treatment or high-pressure plasma micro-arc oxidation treatment; the method of anodization treatment is preferably a hard shield sulfate Anodizing treatment.

Generally speaking, sulfuric acid hard anodizing means that the oxide film obtained after anodizing is larger than 25 microns.

The plate-like product after the oxidation treatment is dried and then processed in step (3). In step (3), the so-called closing treatment is to seal the micropores on the insulating film. This process includes dipping treatment and curing treatment, and dipping treatment is to dip the plate-like product obtained in step (2) into low molecular Among the organic matter or organic glue, the organic glue is preferably a low-viscosity anaerobic glue or non-anaerobic glue; the curing treatment is vacuum, anaerobic or heating to cure the organic matter or organic glue. In general, vacuum or anaerobic curing can be carried out at normal temperature, and heat curing can be carried out under normal atmospheric environment. For example, anaerobic curing can be performed in a carbon dioxide tank or a paraffin bath.

In fact, in step (3), after the dipping and before curing, a cleaning treatment may be performed.

When the metal plating layer is formed in step (4), either chemical copper plating may be performed first to form a bottom copper layer on the insulating film, and then the whole plate copper plating process may be performed, or the whole plate copper plating process may be performed directly.

When electroless copper plating is performed, sensitization treatment may be performed first, for example, treatment with SnCl ₂ ¾ acid solution, followed by activation treatment with colloidal palladium, and then degumming treatment, such as treatment with acid or alkali, so that metal palladium atoms The tree is exposed. Due to the catalytic activity of the metal palladium atom, it can spontaneously lead to the occurrence of electroless copper plating.

In the step (5), the existing conventional techniques can be used for the filming, printing, developing, and pattern plating processes. In step (6), the conventional plating technology and the etching treatment may also use the existing conventional technology; of course, after the etching treatment, further processing such as solder resist, hot air leveling, and printing characters may be performed.

Compared with the existing printed circuit boards made of circuit board plates, printed circuit boards made of metal aluminum, aluminum alloy, metal magnesium, samarium alloy or magnesium aluminum alloy have many advantages: first, the prepared The printed circuit board has good thermal conductivity and heat dissipation, and good flame retardancy. The thermal conductivity of metallic aluminum is second only to that of copper. The finished printed circuit board is directly copper-plated on the oxide film without an adhesive layer, which can dissipate heat in a timely manner, and greatly improve the reliability of electrical components. Second, the dielectric constant of the aluminum oxide film layer is small, which is suitable for high-frequency requirements. Third, it is light in weight and simple in processing technology, which meets the requirements for lightening electrical products. Fourth, the board can be recycled and reused without polluting the environment, and meets environmental protection requirements. Fifth, the metal sheet used has electromagnetic shielding property, which can realize the metalization of small holes and realize the interconnection and interconnection of circuits, so that the anti-electromagnetic interference ability of electronic components is significantly improved.

Compared with the existing printed circuit board made of aluminum oxide sheet and copper foil, the printed circuit board of the present invention has the following advantages: First, the oxide film surface has no adhesive layer for heat insulation, and the heat conduction and heat dissipation are enhanced. Secondly, it can realize the interconnection and interconnection of double-sided circuits, improve the assembling density of electronic components, and meet the requirements of lightness and miniaturization of electronic products.

In short, the printed circuit board of the present invention has better heat dissipation performance and good electromagnetic shielding performance, and can be used in the electronics industry, integrated circuits, and surface-mounted circuit boards that require high heat dissipation performance substrates; for semiconductor refrigerators In the manufacturing field, the printed circuit board of the present invention can replace the existing ceramic sheet. The refrigerator combined with the electric heating reactor not only reduces the cost, but also has good heat dissipation and cooling performance, thereby forming a new type of semiconductor semiconductor. Cooler. Due to the unique technology of the printed circuit board of the present invention, it will have a wide range of applications in various fields such as metallurgy, machinery, electronics, aerospace, weapons, energy, light industry, automobiles, communication equipment, computers, household appliances and the like.

The invention is further described below with reference to the drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged cross-sectional view of a printed circuit board structure of the present invention, wherein: 1 metal substrate 2 holes

3 Oxidation insulation film 4 Circuit metal layer (circuit copper layer)

5 Hole wall metal layer (hole wall copper layer)

FIG. 1 is a cross-sectional view of a printed wiring board cut along a small hole. As shown in FIG. 1, the metal substrate 1 of the printed wiring board of the present invention is provided with a double-sided circuit copper layer 4 on the surface, and an oxide insulating film 3 is provided between the circuit copper layer 4 and the metal substrate 1. The micropores of the insulating film 3 contain a closed-pore low-molecular-weight organic glue, which is a low-viscosity anaerobic glue, which is mainly composed of acrylic acid, methacrylic acid, and esters thereof.

The metal substrate 1 is made of metal aluminum plate, aluminum alloy plate, metal magnesium plate, magnesium alloy plate or aluminum alloy plate. The metal substrate 1 is provided with a hole 2, and a hole copper layer 5 is provided on a wall of the hole 2. The copper layer 4 of the circuit realizes the double-sided circuit interconnection of the metal substrate 1 through the copper layer 5 of the hole wall.

When preparing the printed circuit board of the present invention, the following process flow can be adopted: a. Reviewing the picture, cutting, punching, deburring, and degreasing;

b, oxidation and drying;

c. Dip sealing, cleaning and curing;

d, sensitization, activation, degumming, electroless copper plating, full plate electroplating copper;

e. Foil, printing, development, graphic plating;

f, plating resist, removing film, etching;

g. Remove resist, print solder resist, hot air leveling, print characters, inspection, packaging. Specifically, the printed wiring board of the present invention can be prepared as follows. First, according to the external dimensions on the printed board drawing, metal aluminum plate, aluminum alloy plate, metal magnesium plate, magnesium alloy The gold plate or magnesium aluminum alloy plate 1 is cut according to the size of the pattern. Then, according to the program that has been prepared according to the holes on the drawing, punch holes 2 on the metal plate 1 with punching equipment such as a CNC drilling machine. Deburr the perforated metal plate 1, and then hang the metal plate 1 on the hanger to get the oil from the alkaline degreasing tank. After degreasing, wash with water, pickling and water. The hanger with the metal plate 1 hung in an oxidation tank for anodization. Oxidation methods such as acid hard anodic oxidation or high pressure plasma micro-arc oxidation, the solution can be selected from silicate, phosphate, borate and so on. The surface of the metal plate 1, including the surface of the hole wall, is oxidized in an oxidation bath to form an insulating film 3. The insulating film 3 has many micro holes and is not resistant to corrosion. The metal plate 1 is taken out from the oxidation tank, washed with water, and dried. The metal plate 1 with the insulating film 3 is immersed in a low molecular organic glue, such as a glue composed of acrylic acid and its ester. The glue is a low-viscosity anaerobic glue, which is mainly composed of acrylic acid, fluorenyl acrylic acid, and / or an ester thereof. Remove the metal plate 1 from the gel. When no glue drops, the metal plate 1 is sent to an oxygen-free environment for curing. An anaerobic environment is a carbon dioxide tank or paraffin solution. Take out the anaerobic rubber-cured metal plate 1 and wash away the surface float or paraffin wax. Then, according to the hole metallization process of the printed circuit board, sensitization, activation, degumming, and electroless copper plating are performed. Electroless copper plating uses formaldehyde as a reducing agent. After the substrate is plated to a copper red color in the solution, the whole plate is plated with copper in an acidic copper sulfate plating solution after being washed with water. The thickened substrate is consistent with the existing thick plated substrate of electroless copper plating drilled on the plate, and continues to be processed by conventional printed wiring board processing technology. Use wet or dry film to form photoresist film, and then transfer the image to form circuits. The pattern is plated with acid bright copper, thickened, electroplated lead resist, remove the drug film in alkaline solution, and etch in acid or alkaline. Etching in liquid. After the etching, the surface of the resist layer is removed as shown in the drawing, and a circuit copper layer 4 and a hole wall copper layer 5 are formed. The screen printing solder mask layer is flattened by hot air, and the screen printing characters are made into a finished printed circuit board.

Claims

Rights request

1. A printed circuit board with a metal substrate, a high heat dissipation, and a hole metallization, characterized in that the printed circuit board includes a metal substrate (1) on a surface of the metal substrate (1) A double-sided circuit metal layer (4) and an insulating film (3) between the circuit metal layer (4) and the metal substrate (1); the metal substrate (1) is further provided with a hole ( 2) A hole wall metal layer (5) is provided on the hole wall of the hole (2).

2. The printed wiring board according to claim 1, wherein the metal substrate (1) is made of a metal aluminum plate, an aluminum alloy plate, a metal magnesium plate, a magnesium alloy plate or a magnesium aluminum plate Into.

3. The printed wiring board according to claim 1, wherein the wiring metal layer (4) and the hole wall metal layer (5) are a copper layer and / or a silver layer.

4. The printed wiring board according to claim 1, wherein the insulating film (3) is an oxide film, and a micro-hole in the insulating film (3) contains a type that closes the micro-film. Porous low-molecular-weight organics or organic gums.

5. The printed wiring board according to claim 4, wherein a main component of the organic glue is acrylic acid, methacrylic acid, and / or an ester thereof.

6. The printed wiring board according to claim 1, characterized in that: the wiring metal layer (4) on the surface of the metal substrate (1) and the hole wall metal layer (5) of the hole (2) It is a pattern made according to the design, and the circuit metal layer (4) realizes the interconnection and interconnection of the two sides of the metal substrate (1) through the hole wall metal layer (5).

7. A method for manufacturing a hole-metallized printed circuit board with a metal substrate, comprising the following steps:

(1) Select an appropriate metal substrate and punch holes in the metal substrate;

(2) performing an oxidation treatment on the metal substrate obtained after the punching in step (1) to form an insulating film;

(5) performing the film, plate, development, and pattern plating treatment on the plate-like product obtained in step (4);

(6) The plate-like product obtained in step (5) is subjected to a plating resist and an etching treatment.

8. The method for manufacturing a printed wiring board according to claim 7, wherein the oxidation treatment method in step (2) is an anodization treatment or a high-pressure plasma micro-arc oxidation treatment.

9. The method for manufacturing a printed wiring board according to claim 8, wherein the method of the anodizing treatment is a sulfuric acid hard anodizing treatment.

10. The method for manufacturing a printed wiring board according to claim 7, wherein the sealing process in step (3) comprises a dipping process and a curing process.

11. The method for manufacturing a printed wiring board as claimed in claim 10, wherein the dipping process comprises dipping the plate-like product obtained in step (2) into a low-molecular organic substance or an organic glue.

12. The method for manufacturing a printed wiring board according to claim 11, wherein the organic glue is an anaerobic glue.

13. The method for manufacturing a printed wiring board according to claim 10, wherein the curing process is a method using vacuum, oxygen-free or heating.

14. The method for manufacturing a printed wiring board according to claim 7, wherein forming a metal plating layer in the step (4) comprises performing electroless copper plating to form a bottom copper layer on the insulating film, and then performing a full board Treatment of electroplated copper.

15. The method for manufacturing a printed wiring board according to claim 7, characterized in that, in the step (4), the metal plating layer is formed by directly performing a full-plate electroplated steel treatment.