WO2021143124A1

WO2021143124A1 - Flexible printed circuit board module manufactured using multiple films, and manufacturing method

Info

Publication number: WO2021143124A1
Application number: PCT/CN2020/108994
Authority: WO
Inventors: 王定锋; 徐文红; 冉崇友; 徐磊; 宋健
Original assignee: 王定锋
Priority date: 2020-01-15
Filing date: 2020-08-13
Publication date: 2021-07-22
Also published as: CN113133228A

Abstract

A flexible printed circuit board module manufactured using multiple films, and a manufacturing method. The method comprises: using a high-temperature resistant film to manufacture an upper-layer flexible printed circuit board, and attaching a component (5.1) on the front of the flexible printed circuit board; using a low-temperature resistant film to manufacture a lower-layer flexible printed circuit board provided with a single layer of circuits; and binding, by means of an adhesive (9.1), the flexible printed circuit board provided with the single layer of circuits to the back of the upper-layer flexible printed circuit board soldered with the component (5.1), and then connecting multiple layers of circuits together by means of soldering, or, directly placing the flexible printed circuit board provided with the single layer of circuits on the back of the upper-layer flexible printed circuit board soldered with the component (5.1), and then implementing a welding connection (8.1a), thereby forming a flexible printed circuit board module including multiple films and provided with two or three layers of flexible circuits. The cost of the flexible printed circuit board module manufactured using multiple films is significantly lower than the cost of a flexible circuit board module manufactured using a single film.

Description

Flexible circuit board module made of multiple films and manufacturing method

Technical field

The invention relates to the field of circuit boards, in particular to flexible circuit board modules made of multiple films and a manufacturing method.

Background technique

Existing flexible circuit boards require reflow soldering in the production and processing behind them. The temperature resistance needs to reach 190℃ or higher within a certain period of time, and the temperature is relatively high. Therefore, the material requirements for flexible circuit boards must reach the corresponding temperature resistance level, resulting in flexibility. The material cost of the circuit board is high.

In order to overcome the above shortcomings and shortcomings, the present invention uses the following new invention technology to make flexible circuit board modules, and use higher temperature resistant films to make flexible circuit boards. After the components are attached to the front of the flexible circuit board, the components are soldered on the flexible On the circuit board, make a flexible circuit board with components for the upper layer, and then use a lower temperature resistant film to make a single-layer circuit. The flexible circuit board without components is used on the lower layer, and then glue is used for the upper and lower flexible circuits. The boards are glued together and soldered together, or the upper and lower flexible circuit boards are directly welded together. The flexible circuit board modules with multiple films are the modules of double-layer flexible circuit boards, or A three-layer wire board module, the upper flexible circuit board made of a higher temperature resistant film, and when the film used is a PI film, the lower flexible circuit board is a single-layer flexible circuit board, Or a double-layer flexible circuit board, the lower temperature resistant film used is all PVC film, or all PET film, or one layer of PVC film and the other layer is PET film, the upper layer is resistant to higher temperature When the film used is a PET film, the flexible circuit board in the lower layer is a single-layer flexible circuit board or a double-layer flexible circuit board, and the lower temperature resistance The film is PVC film, or one layer of PVC film and the other layer is PET film. The cost of flexible circuit board modules made of multiple films is significantly lower than that of flexible circuit board modules made of one film. the cost of.

Summary of the invention

The invention relates to a flexible circuit board module made of a variety of films and a manufacturing method. Specifically, a higher temperature resistant film is used to make a flexible circuit board on the upper layer. After components are attached to the front of the flexible circuit board, a lower temperature resistant film is used. Make the flexible circuit board of the lower single-layer circuit with the film, glue the single-layer flexible circuit board to the back of the upper flexible circuit board of the soldered component, and then use solder to make the several layers of circuits conductive, or directly connect the single-sided board It is placed on the back of the upper flexible circuit board of the soldered component, and then welded and connected to form a flexible double-layer or three-layer flexible circuit board module with multiple films. The cost of the flexible circuit board module made of multiple films is significantly lower than the cost of the flexible circuit board module made of one film.

According to the present invention, a method for manufacturing flexible circuit board modules made of multiple films is provided. Specifically, a higher temperature resistant film is used to make the upper flexible circuit board, and the upper flexible circuit board is mounted on the front surface of the flexible circuit board. , Through reflow soldering, the components are soldered on the upper flexible circuit board to make the upper flexible circuit board with the components, and then the lower temperature resistant film is used to make the single-layer circuit and the lower flexible circuit board. Then use glue to glue the flexible circuit board with components on the upper layer and the flexible circuit board on the lower layer, and solder them together, or directly connect the flexible circuit board with components on the upper layer, and The flexible circuit boards in the lower layer are welded together to make a flexible circuit board module made of a variety of films. The flexible circuit board module of the multiple films is a double-layer flexible circuit board module, or a three-layer flexible circuit board module. A flexible circuit board module, the upper flexible circuit board made of a higher temperature resistant film, when the film used is PI film, the lower flexible circuit board is a single-layer film Flexible circuit board, or double-layer flexible circuit board, the lower temperature resistant film used is PVC film, or PET film, or one layer of PVC film and the other layer is PET film, which is on the upper layer A flexible circuit board made of a higher temperature resistant film, when the film used is a PET film, the flexible circuit board in the lower layer is a single-layer flexible circuit board or a double-layer flexible circuit board. The lower temperature resistant film is PVC film, or one layer of PVC film and the other layer is PET film. The bonding between all circuit layers of the flexible circuit board and the film is made by adhesive bonding. Overall, the cost of the flexible circuit board module made of multiple films is significantly lower than the cost of the flexible circuit board module made of one film.

According to the present invention, a flexible circuit board module made of a variety of films is also provided, including: components on the top layer; a flexible circuit board on the upper layer made of a higher temperature resistant film; and a lower temperature resistant film made The flexible circuit board in the lower layer; characterized in that the components on the top layer are soldered on the flexible circuit board on the upper layer, and the flexible circuit boards on the upper and lower layers are glued together and used Tin makes the flexible circuit boards on the upper and lower layers welded together, or the flexible circuit boards on the upper and lower layers are directly soldered together. The flexible circuit board modules of the various films are described. It is a flexible circuit board module with a double-layer circuit, or a flexible circuit board module with a three-layer circuit. The upper layer of the flexible circuit board is made of a higher temperature resistant film. When the film used is a PI film, The flexible circuit board in the lower layer is a single-layer flexible circuit board, or a double-layer flexible circuit board, and the lower temperature-resistant film used is a PVC film, or a PET film, or a layer of PVC The other layer of the film is a PET film. The flexible circuit board on the upper layer is made of a higher temperature resistant film. When the film used is a PET film, the flexible circuit board on the lower layer is a single-layer film. The flexible circuit board is either a double-layered flexible circuit board, the lower temperature resistant film in the lower layer is a PVC film, or a layer of PVC film and the other layer is a PET film, all of the flexible circuit board The combination between the circuit layer and the film is made by adhesive bonding into a whole. The cost of this flexible circuit board module made of multiple films is significantly lower than that of a flexible circuit made of one film The cost of the circuit board module.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that when the flexible circuit board module of the multiple films is a double-layer circuit module, the The flexible circuit board on the upper layer is a single-layer circuit flexible circuit board.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that when the flexible circuit board module of the multiple films is a three-layer circuit module, the The above-mentioned flexible circuit board is a double-layer circuit flexible circuit board.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple types of films is characterized in that the multiple types are two or three types.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that, when the flexible circuit board in the lower layer is a layer of film, the flexible circuit board is in the lower layer. The other side of the circuit of the flexible circuit board can be used to make an insulating layer with solder mask.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that the upper flexible circuit board is a flexible circuit board for soldering components. The solder mask of the flexible circuit board on the side is an ink solder mask.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that the upper flexible circuit board is a flexible circuit board for soldering components. The solder mask of the flexible circuit board on the surface is a cover film solder mask, and the cover film used is also a PI film or a PET film that is resistant to higher temperatures.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that the higher temperature resistant film is a film that can withstand the reflow temperature of the SMT process soldering components. When using low temperature solder paste, the reflow soldering temperature reaches at least 160 degrees Celsius. When using low temperature solder paste, the higher temperature resistant film is PI film or PET film. The reflow soldering temperature with high temperature solder paste reaches at least 240 degrees Celsius. When using high-temperature solder paste, the high-temperature-resistant film is PI film.

According to a preferred embodiment of the present invention, the flexible circuit board module made of multiple films is characterized in that the lower temperature-resistant film is compared in the flexible circuit board module, which is relatively The higher temperature-resistant film has a lower temperature resistance level, and is a film that cannot withstand the reflow temperature when soldering components in the SMT process. The reflow temperature when using low temperature solder paste is at least 160 degrees Celsius, and the reflow temperature when using high temperature solder paste At least 240 degrees Celsius.

In the following description of the drawings and specific embodiments, details of one or more embodiments of the present invention will be explained.

Description of the drawings

The features, objects and advantages of the present invention will become more apparent by reading this specification in conjunction with the following drawings. A brief description of the drawings is as follows.

Figure 1 is a plan view of a flexible circuit board with a single-layer circuit on the upper layer.

2 is a schematic cross-sectional view of a flexible circuit board with a PI film single-layer copper-clad substrate and an upper single-layer circuit with a front PI cover film.

3 is a schematic cross-sectional view of a flexible circuit board with a single-layer copper-clad PI film and a front-side solder resist ink.

4 is a schematic cross-sectional view of a flexible circuit board with a PET film single-layer copper-clad substrate and an upper single-layer circuit with a front PET cover film.

Fig. 5 is a schematic cross-sectional view of a flexible circuit board with a single-layer copper-clad PET film and an upper single-layer circuit with a front solder resist ink.

Fig. 6 is a schematic plan view of the flexible circuit board of the upper double-layer circuit.

FIG. 7 is a schematic cross-sectional view of a flexible circuit board with a double-layer circuit on the upper layer of the PI cover film on the front and back sides of the PI substrate.

FIG. 8 is a schematic cross-sectional view of a flexible circuit board with a double-layer circuit on the upper layer of the front and back PET covering film and PI substrate.

9 is a schematic cross-sectional view of a flexible circuit board with a double-layer circuit on the upper layer of the PET cover film on the front and back sides of the PET substrate.

FIG. 10 is a schematic cross-sectional view of a flexible circuit board with a double-layer circuit on the upper layer of the PI substrate with solder mask ink on the front and back sides.

FIG. 11 is a schematic cross-sectional view of a flexible circuit board with a double-layer circuit on the upper layer of a PET substrate with solder resist ink on the front and back sides.

Fig. 12 is a schematic plan view of a flexible circuit board module with an upper single-layer circuit with components.

Fig. 13 is a schematic plan view of a flexible circuit board module with an upper double-layer circuit with components.

Figure 14 is a schematic plan view of a single-layer flexible circuit board made of a layer of PVC film.

Figure 15 is a schematic plan view of a single-layer flexible circuit board made of a layer of PET film.

Figure 16 is a schematic plan view of a single-layer flexible circuit board made of two-layer PVC film on the front and PET on the back.

Figure 17 is a schematic plan view of a flexible circuit board module made of various films.

Fig. 18 is a schematic cross-sectional view showing that the flexible circuit boards on the upper and lower layers are not glued and only welded together.

Figure 19 is a schematic cross-sectional view of the flexible circuit boards on the upper and lower layers glued together and welded together.

Detailed ways

Hereinafter, the present invention will be described in detail by taking a preferred embodiment as an example.

However, those skilled in the art should understand that the following descriptions are merely examples to illustrate and describe some preferred embodiments, and do not have any limitation on the claims of the present invention.

Example

1. Production of the upper flexible circuit board

1.1. Production of flexible circuit board for upper single-layer circuit

After preparing the PI film single-layer copper-clad substrate 1.1a or the PET film single-layer copper-clad substrate 1.1b, the copper foil and the film of the copper-clad substrate are bonded together with an epoxy-based adhesive. Print the circuit on the copper surface. After the ink is removed by etching in the etching machine, the solder mask with the pad window is pasted on the front. The solder mask is also a higher temperature resistant PI cover film 2.1a with glue or a PET cover with glue. Film 2.1b, or printed solder mask ink for solder mask 2.1c, after OSP processing, drilled tin guide holes 3.1, made into a flexible circuit board on the upper single-layer circuit (Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, shown).

1.2. Production of the flexible circuit board of the upper double-layer circuit

Use PI film made of double-layer copper clad laminate 4.1a or PET film made of double-layer copper clad laminate 4.1b, after drilling 3.2, sinking copper and plating copper, paste anti-etching dry film, expose, develop, etch, and retreat In addition to the anti-etching dry film, paste the PI cover film 2.1a with glue, or the PET cover film 2.1b with glue on the front and back of the opened pad window, or print the solder mask ink for solder mask 2.1c, and make it on the upper layer The flexible circuit board of the double-layer circuit (Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11).

2. SMT paste components

Put the above two types of flexible circuit boards on the front of the flexible circuit board, print solder paste, paste components 5.1, reflow, solder the components on the front, and make the upper flexible circuit board module with components (Figure 12, Shown in Figure 13).

3. Production of the lower single-layer flexible circuit board

3.1. Single-layer flexible circuit board made of one layer of film

Multiple copper-clad aluminum wires 7.1 are pasted with glued PET film 2.1b or PVC film 6.1 to form the lower single-layer single-layer sheet of the single-layer film (shown in Figure 14 and Figure 15).

3.2. Single-layer flexible circuit board made of two-layer film

A layer of glued PET film 2.1b and a layer of glued PVC film 6.1 are sandwiched and juxtaposed flat copper-clad aluminum-magnesium wire 7.1, and then laminated together, and then cut and connect the front flexible circuit with a laser on one side of the PET The copper surface required for the board is formed with pads 8.1, and then the surface is treated with anti-oxidation to make the lower single-layer flexible circuit board (shown in Figure 16).

4. Assembly

4.1 Direct welding assembly

Respectively assemble the above-mentioned upper flexible circuit board modules with components on the above-mentioned lower single-layer panels, and weld the upper and lower flexible circuit boards together with tin wire and ferrochrome. Then heating makes the welding conduction 8.1a between the upper flexible circuit board and the lower flexible circuit board, and a flexible circuit board module made of various films (shown in Figure 17 and Figure 18) is made.

Description: The description of the drawings only takes the flexible circuit board of the upper single-layer circuit and the single-layer flexible circuit board made of the lower layer of film as an example for illustration.

4.2 Welding assembly after bonding with glue

Respectively assemble the above several types of upper flexible circuit board modules with components on the non-component side with glue 9.1, avoiding the tin hole when printing glue, and assemble them on the above several types of lower single-layer circuit flexible circuit boards , Use tin wire and ferrochrome to weld the upper and lower flexible circuit boards together. Then heat the upper flexible circuit board and the lower flexible circuit board to conduct welding 8.1a, and the flexible circuit board module made of various films containing glue (shown in Figure 17 and Figure 19) is made.

The specific embodiments of the flexible circuit board module made of various films and the manufacturing method have been described in detail above in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above descriptions are merely examples to illustrate and describe some specific embodiments, and do not have any limitation on the scope of the present invention, especially the scope of the claims.

Claims

The manufacturing method of flexible circuit board modules made of a variety of films, specifically, the upper flexible circuit board is made with a higher temperature resistant film, and the components are pasted on the front surface of the upper flexible circuit board, and then reflow soldering is used. The components are soldered on the upper flexible circuit board to make the upper flexible circuit board with the components, and then the lower temperature-resistant film is used to make the single-layer circuit and the lower layer flexible circuit board. The flexible circuit board with components on the upper layer is glued to the flexible circuit board on the lower layer and connected together by soldering, or directly connect the flexible circuit board with components on the upper layer and the flexible circuit on the lower layer The boards are welded together to produce a flexible circuit board module made of a variety of films, the flexible circuit board module of the multiple films is a double-layer flexible circuit board module, or a three-layer flexible circuit board Module, the upper flexible circuit board made of a higher temperature resistant film, when the film used is PI film, the lower flexible circuit board is a single-layer flexible circuit board, or It is a double-layer flexible circuit board, the lower temperature resistant film used is PVC film, or PET film, or one layer of PVC film and the other layer is PET film. The upper layer is higher temperature resistant The flexible circuit board made of film, when the film used is PET film, the flexible circuit board in the lower layer is a single-layer flexible circuit board or a double-layer flexible circuit board, and the lower temperature resistant The film is a PVC film, or a layer of PVC film and the other layer is a PET film. All the circuit layers of the flexible circuit board and the film are combined into a whole by adhesive bonding. The cost of a flexible circuit board module made of multiple films is significantly lower than the cost of a flexible circuit board module made of one film.
Flexible circuit board modules made of a variety of films, including:

Components at the top level;

A flexible circuit board on the upper layer made of a higher temperature resistant film;

Flexible circuit board in the lower layer made of low temperature resistant film;

It is characterized in that the components on the top layer are soldered on the flexible circuit board on the upper layer, and the flexible circuit boards on the upper and lower layers are glued together, and tin is used to make the upper and lower flexible circuit boards. The circuit boards are welded together, or the flexible circuit boards on the upper and lower layers are directly connected by soldering. The flexible circuit board modules of the various films are the flexible circuit board modules of double-layer circuits. Group, or a three-layer circuit flexible circuit board module, the upper flexible circuit board made of a higher temperature resistant film, when the film used is PI film, the flexible circuit in the lower layer The board is a single-layer flexible circuit board or a double-layer flexible circuit board. The lower temperature-resistant film used is PVC film, or PET film, or one layer of PVC film and the other layer is PET film, so The above-mentioned flexible circuit board made of a higher temperature resistant film, when the film used is a PET film, the flexible circuit board at the lower layer is a single-layer flexible circuit board or a double-layer film Flexible circuit board, the lower temperature resistant film in the lower layer is a PVC film, or a layer of PVC film and the other layer is a PET film, between all circuit layers of the flexible circuit board and the film The combination of the two is made by adhesive bonding to form a whole. The cost of the flexible circuit board module made of multiple films is significantly lower than the cost of the flexible circuit board module made of one film.
The flexible circuit board module made of multiple films according to claim 1 or 2, wherein when the flexible circuit board module of the multiple films is a double-layer circuit module, the The flexible circuit board on the upper layer is a single-layer flexible circuit board.
The flexible circuit board module made of multiple films according to claim 1 or 2, wherein when the flexible circuit board module of the multiple films is a three-layer circuit module, the The flexible circuit board on the upper layer is a double-layer circuit flexible circuit board.
The flexible circuit board module made of multiple types of films according to claim 1 or 2, wherein the multiple types are two or three types.
The flexible circuit board module made of multiple films according to claim 1 or 2, wherein when the flexible circuit board at the lower layer is a layer of film, the flexible circuit board at the lower layer The other side of the circuit of the board can be used to make an insulating layer with solder mask.
The flexible circuit board module made of multiple films according to claim 1 or 2, wherein the flexible circuit board on the upper layer is a flexible circuit board for soldering components, and the flexible circuit board on the soldering surface of the component is flexible The solder mask of the circuit board is the ink solder mask.
The flexible circuit board module made of multiple films according to claim 1 or 2, wherein the upper flexible circuit board is a flexible circuit board for soldering components, and the flexible circuit board on the soldering surface of the component is flexible The solder mask of the circuit board is a cover film solder mask, and the cover film used is also a PI film or a PET film that can withstand higher temperatures.
The flexible circuit board module made of multiple films according to claim 1 or 2, characterized in that the higher temperature resistant film is a film that can withstand the reflow temperature of the SMT process when soldering components. The reflow temperature of solder paste should reach at least 160 degrees Celsius. When low temperature solder paste is used, the higher temperature resistant film is PI film or PET film, and the reflow temperature of high temperature solder paste should reach at least 240 degrees Celsius. In the case of high-temperature solder paste, the higher temperature-resistant film is PI film.
The flexible circuit board module made of multiple films according to claim 1 or 2, wherein the lower temperature-resistant film is compared in the flexible circuit board module, and is relatively high-temperature resistant in the module. The film has a lower temperature resistance level and is a film that cannot withstand the reflow temperature when soldering components in the SMT process. The reflow temperature when using low temperature solder paste is at least 160 degrees Celsius, and the reflow temperature when using high temperature solder paste is at least Celsius. 240 degrees.