CN116367443A

CN116367443A - Non-electroplating continuous flexible circuit board and preparation method thereof

Info

Publication number: CN116367443A
Application number: CN202310274166.1A
Authority: CN
Inventors: 王吉元; 高钟淦; 陈江波; 罗隆恒
Original assignee: Zhuhai Huiyihong Photoelectric Co ltd
Current assignee: Zhuhai Huiyihong Photoelectric Co ltd
Priority date: 2023-03-20
Filing date: 2023-03-20
Publication date: 2023-06-30

Abstract

The invention provides a non-electroplating continuous flexible circuit board and a preparation method thereof, wherein a back adhesive substrate is identified by a CCD and then is subjected to punching treatment to obtain the back adhesive substrate with side holes and through holes; combining the copper foil with the back adhesive base material, and baking and curing to obtain a substrate; cleaning the substrate, and covering the front and back sides of the cleaned substrate with dry films to obtain a substrate with the front and back sides provided with dry films; positioning the substrate through the identification side holes, and performing exposure treatment; the substrate after exposure treatment is sequentially subjected to etching and film stripping treatment to obtain the flexible circuit board with the metal circuit, then the flexible circuit board is tested, and after the flexible circuit board qualified in the test is subjected to film pasting treatment, the flexible circuit board is baked to obtain a target flexible circuit board, so that the problem that the flexible printed circuit board obtained by processing in an electroplating manner has a fixed length is avoided, the working hours of subsequent assembly are effectively reduced, and meanwhile, welding materials are saved.

Description

Non-electroplating continuous flexible circuit board and preparation method thereof

Technical Field

The invention relates to the technical field of flexible circuit boards, in particular to a non-electroplating continuous flexible circuit board and a preparation method thereof.

Background

The flexible circuit board (Flexible Printed Circuit Board) is called a flexible board for short, is commonly called an FPC in industry, and is a printed circuit board made of flexible insulating base materials (mainly polyimide or polyester films). The FPC is utilized to greatly reduce the volume of the electronic product, and is suitable for the requirements of the electronic product on development in the high-density, miniaturized and high-reliability directions. Therefore, FPCs have been widely used in the fields or products of aerospace, military, mobile communication, portable computers, computer peripherals, PDAs, digital cameras, and the like.

Generally, the flexible printed circuit board is usually processed by adopting an electroplating mode, the electroplating mode not only affects the health of a human body, but also needs to treat dangerous waste generated by the electroplating mode, thereby increasing extra cost.

Disclosure of Invention

Based on this, the invention aims to provide an electroless continuous flexible circuit board and a preparation method thereof, and aims to solve the problems that in the prior art, flexible printed circuit boards processed by adopting an electroplating mode have fixed lengths, and in order to adapt to different application scenes, flexible printed circuit boards with one section must be welded, so that a large amount of working hours and welding materials are consumed.

According to the preparation method of the electroless continuous flexible circuit board, the method comprises the following steps:

after the back adhesive base material is identified by a CCD, punching treatment is carried out to obtain the back adhesive base material with side holes and through holes;

combining the copper foil with a back adhesive base material with side holes and through holes, and baking and curing to obtain a substrate;

cleaning the substrate, and covering the front and back sides of the cleaned substrate with dry films to obtain a substrate with dry films on the front and back sides;

positioning the substrate with the dry films on the front side and the back side by identifying the side holes, and performing exposure treatment;

sequentially etching and film stripping the substrate after exposure treatment to obtain a flexible circuit board with a metal circuit;

testing the flexible circuit board with the metal circuit, and performing film pasting treatment on the flexible circuit board which is qualified in the test to obtain the flexible circuit board with the protective film;

and baking the flexible circuit board with the protective film to obtain the target flexible circuit board.

Further, the width of the back adhesive base material is larger than the width of the copper foil.

Further, in the step of combining the copper foil with the back adhesive base material with the side holes and the through holes, the copper foil is placed on the adhesive surface of the back adhesive base material with the side holes and the through holes, and the copper foil is combined with the back adhesive base material with the side holes and the through holes by a circular knife machine and a deviation corrector combined wheel and heated to 115-125 ℃ for pre-curing.

Further, in the step of combining the copper foil with the back adhesive base material with the side holes and the through holes, and baking and curing the back adhesive base material to obtain the substrate, the copper foil is combined with the back adhesive base material with the side holes and the through holes, and then baked and cured by a loop oven to obtain the substrate, wherein the baking temperature set by the loop oven is 155-165 ℃, and the baking time is 10-20 min.

Further, in the step of cleaning the substrate, the substrate is automatically wound and unwound by a horizontal microetching line to be cleaned, one end of the horizontal microetching line is provided with a discharging device, and the other end of the horizontal microetching line is provided with a winding device, wherein the discharging device is used for automatically winding the reel-shaped substrate, so that the flat substrate flows into the horizontal microetching device, and the winding device is used for winding the flat substrate flowing out of the horizontal microetching device into the reel-shaped substrate.

Further, in the step of covering the front and back sides of the cleaned substrate with dry films to obtain the substrate with the dry films on the front and back sides, the cleaned substrate is subjected to film pressing on the front and back sides through an automatic dry film sticking machine, the temperature of the automatic dry film sticking machine is set to 120-125 ℃, the film pressing speed is set to 2.5-3.5 m/min, one end of the automatic dry film sticking machine is provided with the discharging device, and the other end of the automatic dry film sticking machine is provided with the collecting device.

Further, the substrate with the dry films on the front side and the back side is positioned by identifying the side holes, and in the step of exposing, the substrate with the dry films on the front side and the back side is placed into an exposure machine to finish the exposing, wherein one end of the exposure machine is provided with the discharging device, and the other end of the exposure machine is provided with the receiving device.

Further, in the step of sequentially performing etching and film removing treatment on the substrate subjected to exposure treatment to obtain the flexible circuit board with the metal circuit, the substrate subjected to exposure treatment is placed in a horizontal DES line, and sequentially subjected to etching and film removing treatment to obtain the flexible circuit board with the metal circuit, wherein one end of the horizontal DES line is provided with the discharging device, and the other end of the horizontal DES line is provided with the receiving device.

Further, the step of testing the flexible circuit board with the metal circuit and performing film pasting treatment on the flexible circuit board which is qualified in the test to obtain the flexible circuit board with the protective film comprises the following steps:

comparing patterns of the flexible circuit board with the metal circuit through the AOI equipment, and judging whether the patterns are preset patterns or not;

if yes, carrying out open-short circuit test on the flexible circuit board with the metal circuit;

and pasting cover films on the front side and the back side of the flexible circuit board which is qualified in open-short circuit test, and pressing through a quick press to obtain the flexible circuit board with the protective film, wherein the temperature of the quick press is set to be 180-185 ℃, the precompression is 25-35 kg, the precompression time is 8-12 s, the molding pressure is 125-135 kg, and the molding time is 20-40 s.

According to the embodiment of the invention, the non-electroplating continuous flexible circuit board is prepared by the preparation method of the non-electroplating continuous flexible circuit board.

Compared with the prior art: the method comprises the steps of identifying a back adhesive base material through a CCD, and then punching to obtain the back adhesive base material with side holes and through holes; combining the copper foil with a back adhesive base material with side holes and through holes, and baking and curing to obtain a substrate; cleaning the substrate, and covering the front and back sides of the cleaned substrate with dry films to obtain a substrate with the front and back sides provided with dry films; positioning the substrate with the dry films on the front side and the back side through identifying the side holes, and performing exposure treatment; sequentially etching and film stripping the substrate after exposure treatment to obtain a flexible circuit board with a metal circuit; testing the flexible circuit board with the metal circuit, and performing film pasting treatment on the flexible circuit board which is qualified in the test to obtain the flexible circuit board with the protective film; the flexible printed circuit board with the protective film is baked to obtain the target flexible printed circuit board, so that the problem that the flexible printed circuit board obtained by processing in an electroplating mode has a fixed length is avoided, the working hours of subsequent assembly are effectively reduced, and meanwhile, welding materials are saved.

Drawings

Fig. 1 is a flowchart of a preparation method of a non-electroplating continuous flexible circuit board according to an embodiment of the present invention.

Detailed Description

In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, a flowchart of a method for manufacturing a non-electroplating continuous flexible circuit board according to an embodiment of the present invention is provided, and the method specifically includes steps S01 to S07, where:

and S01, identifying the back adhesive base material through a CCD, and then punching to obtain the back adhesive base material with side holes and through holes.

The adhesive is an insulating colloid, the plastic film is an insulating layer, and the insulating colloid can be any one of an adhesive or a thermosetting adhesive film.

In this embodiment, a backing substrate with a width of 255mm is adopted, and the backing substrate is put into an automatic punching machine with a recognition function of a CCD (Charge coupled Device ), and as a marking point can be manufactured in advance on the backing substrate, firstly, the marking point of the backing substrate can be recognized through the CCD, after the backing substrate is corrected, a side hole and a via hole are punched, wherein the side hole is positioned at the edge close to the length direction of the backing substrate, and the via hole is mainly used for brushing tin through a main line position in the subsequent preparation process, namely, the front surface of the backing substrate is penetrated by tin through the via hole from the front surface to the back surface of a circuit board, so that double-sided conduction is realized more conveniently, and the stability of performance can be ensured.

And S02, combining the copper foil with a back adhesive base material with side holes and through holes, and baking and curing to obtain the substrate.

In this embodiment, the width of the copper foil may be 246mm, that is, the width of the back adhesive substrate is greater than the width of the copper foil, which aims to make the copper foil be completely covered by the back adhesive substrate, with a certain tolerance, specifically, firstly, the copper foil is aligned with the back adhesive substrate having the side holes and the through holes, the copper foil is placed on the side of the back adhesive substrate having the glue through a tooling, then the copper foil and the back adhesive substrate are passed through a circular cutter machine together under the correction of a deviation corrector combination wheel, and the temperature is raised to 115-125 ℃ for pre-curing, wherein the circular cutter machine is also called a multi-station rotary cutter machine, and also called a hob machine or a circular cutter die cutter machine. The continuous rotary die cutting processing in the form of a hob is one of the devices with highest production efficiency in a die cutting machine, and the die-cut product is widely applied to the fields of mobile phones, computers, liquid crystal displays, digital cameras, LCD backlights and the like.

It should be noted that, the side hole on the back adhesive substrate cannot be covered by the copper foil, and the main reason is that the side hole plays a role in positioning in each process of the back adhesive substrate, if covered, the positioning accuracy will be reduced, and even the yield cannot be ensured. In addition, as the temperature is raised to 115-125 ℃ and only pre-curing is carried out, the copper foil and the back adhesive base material are not separated under the condition of a certain external force.

Further, after the copper foil is combined with the back adhesive base material with the side holes and the through holes, baking and curing are carried out through a loop-shaped baking oven to obtain the base plate, wherein the baking temperature set by the loop-shaped baking oven is 155-165 ℃ and the baking time is 10-20 min, it is understood that the loop-shaped baking oven can be formed by combining a loop-shaped transmission line with the baking oven, the copper foil and the back adhesive base material with the side holes and the through holes can be placed on the loop-shaped transmission line, and the copper foil and the back adhesive base material with the side holes and the through holes can flow through the baking oven under the transmission of the loop-shaped transmission line, and the baking time is kept within 10-20 min by controlling the transmission speed of the transmission line, namely the pulling speed. The purpose of baking and curing by adopting the oven in a shape of a loop is to take into consideration that the copper foil and the back adhesive base material with the side holes and the through holes are combined to be baked in a roll shape, so that a plurality of adhesive surface parts on the back adhesive base material can be mutually adhered, and the follow-up production is not facilitated.

And S03, cleaning the substrate, and covering the front and back sides of the cleaned substrate with dry films to obtain the substrate with the dry films on the front and back sides.

Specifically, the substrate is automatically wound and unwound through the horizontal microetching line to be cleaned, one end of the horizontal microetching line is a discharging device, the other end of the horizontal microetching line is a receiving device, wherein the discharging device is used for automatically unwinding a reel-shaped substrate, the flat substrate flows into the horizontal microetching device, the receiving device is used for winding the flat substrate flowing out of the horizontal microetching device into the reel-shaped substrate, a microetching liquid is generally adopted to clean the substrate in the microetching device, the microetching liquid is required to have small change amplitude of etching rate, the process is more uniform, mild and good in controllability, and secondly, the surface appearance of the microetching metal is good, the etched surface is uniform and consistent, the surface bonding strength is better, in addition, the surface is easy to clean, secondary reaction is avoided, and the surface is not oxidized.

It can be understood that the above-mentioned discharging device and the receiving device are actually the same type of device, specifically, for the horizontal microetching device, the discharging device is placed at the input end of the horizontal microetching device, the receiving device is placed at the output end of the horizontal microetching device, for the loop oven, the discharging device is placed at the output end of the loop oven, and similarly, for the automatic dry film sticking machine, the receiving device is placed at the output end of the horizontal microetching device, is placed at the input end of the automatic dry film sticking machine.

Further, the cleaned substrate is subjected to film pressing on the front side and the back side through an automatic dry film sticking machine, the temperature of the automatic dry film sticking machine is set to be 120-125 ℃, the film pressing speed is set to be 2.5-3.5 m/min, a discharging device is arranged at one end of the automatic dry film sticking machine, a receiving device is arranged at the other end of the automatic dry film sticking machine, and the automatic dry film sticking machine is particularly used for covering photosensitive materials on the front side and the back side of the substrate.

And S04, positioning the substrate with the dry films on the front side and the back side by identifying the side holes, and performing exposure treatment.

Specifically, the substrate with the dry films on the front surface and the back surface is placed into an exposure machine to complete exposure treatment, wherein one end of the exposure machine is provided with a discharging device, and the other end of the exposure machine is provided with a receiving device.

And step S05, sequentially etching and film stripping the substrate subjected to the exposure treatment to obtain the flexible circuit board with the metal circuit.

Specifically, the front and back sides of the substrate after exposure treatment are developed to form a metal circuit protection layer, the substrate after exposure treatment is placed in a horizontal DES (development etching film stripping) line, and the flexible circuit board with the metal circuit is obtained through etching and film stripping treatment in sequence, wherein a discharging device is arranged at one end of the horizontal DES line, and a receiving device is arranged at the other end of the horizontal DES line.

And step S06, testing the flexible circuit board with the metal circuit, and performing film pasting treatment on the flexible circuit board which is qualified in the test to obtain the flexible circuit board with the protective film.

Specifically, a flexible circuit board with a metal circuit is subjected to pattern comparison through an AOI (automatic optical inspection) device, whether the pattern is a preset pattern or not is judged, if the pattern is judged to be the preset pattern, an open-short circuit test is carried out on the flexible circuit board with the metal circuit, then a cover film is attached to the front side and the back side of the flexible circuit board qualified in the open-short circuit test, and lamination is carried out through a quick press, so that the flexible circuit board with a protective film is obtained, wherein the temperature of the quick press is set to 180-185 ℃, the pre-pressing force is 25-35 kg, the pre-pressing time is 8-12 s, the molding pressure is 125-135 kg, and the molding time is 20-40 s. It should be noted that, in other embodiments of the present invention, a method of drilling a hole and pasting a cover film may be used to obtain a flexible circuit board with a protective film, which is cheaper than a whole roll of film.

And S07, baking the flexible circuit board with the protective film to obtain the target flexible circuit board.

In this embodiment, before baking treatment, the flexible circuit board with the protective film may be placed into an automatic screen printer with a CCD according to customer requirements, after the whole roll of flexible circuit board is identified, characters or symbols are printed at a preset position, after screen printing, the whole roll of flexible circuit board is unwound, the shaft core is taken out, baking treatment is performed in an oven, wherein the baking temperature is set to 155-165 ℃ and the baking time is 3 hours, and after baking is finished, the target flexible circuit board is obtained, and it is required that the thickness of the front circuit, namely the back adhesive substrate, may be 18 μm, 22 μm, 25 μm, 35 μm, etc., while not limited thereto; the thickness of the back surface wiring, i.e., copper foil, may be 18 μm, 22 μm, 25 μm, 35 μm, 50 μm, 70 μm, 105 μm, etc., but is not limited thereto.

Further, in order to make the target flexible circuit board more conform to customer demands, the target flexible circuit board can be subjected to anti-oxidation treatment, specifically, the target flexible circuit board is placed in a horizontal anti-oxidation line so as to be provided with a protective film at a welding position, and then the target flexible circuit board is subjected to pre-inspection (defective products are detected and marks are made), parting (an automatic punching machine is used for cutting the customer to a required length through a die and parting the damaged board), forming (the parting is completed through the die through the punching machine), final inspection and packaging, and finally delivered to the customer.

In summary, in the embodiment of the invention, the back adhesive substrate with the side holes and the through holes is obtained by carrying out punching treatment after the back adhesive substrate is identified by the CCD; combining the copper foil with a back adhesive base material with side holes and through holes, and baking and curing to obtain a substrate; cleaning the substrate, and covering the front and back sides of the cleaned substrate with dry films to obtain a substrate with the front and back sides provided with dry films; positioning the substrate with the dry films on the front side and the back side through identifying the side holes, and performing exposure treatment; sequentially etching and film stripping the substrate after exposure treatment to obtain a flexible circuit board with a metal circuit; testing the flexible circuit board with the metal circuit, and performing film pasting treatment on the flexible circuit board which is qualified in the test to obtain the flexible circuit board with the protective film; the flexible printed circuit board with the protective film is baked to obtain the target flexible printed circuit board, so that the problem that the flexible printed circuit board obtained by processing in an electroplating mode has a fixed length is avoided, the working hours of subsequent assembly are effectively reduced, and meanwhile, welding materials are saved.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A method of manufacturing a non-plated continuous flexible circuit board, the method comprising:

2. The method of manufacturing a continuous flexible circuit board according to claim 1, wherein the width of the back adhesive base material is larger than the width of the copper foil.

3. The method of manufacturing a continuous flexible circuit board according to claim 1, wherein in the step of combining the copper foil with the back adhesive base material having the side holes and the through holes, the copper foil is placed on the adhesive surface of the back adhesive base material having the side holes and the through holes, and the copper foil is combined with the back adhesive base material having the side holes and the through holes by a circular knife machine and a deviation corrector combining wheel, and is heated to 115 ℃ to 125 ℃ for pre-curing, so that the copper foil is combined with the back adhesive base material having the side holes and the through holes.

4. The method for manufacturing a continuous flexible circuit board according to claim 3, wherein in the step of combining the copper foil with the back adhesive base material having the side holes and the through holes, and baking and curing, the copper foil is baked and cured by a loop oven after being combined with the back adhesive base material having the side holes and the through holes, so as to obtain the substrate, wherein the baking temperature set by the loop oven is 155-165 ℃ and the baking time is 10-20 min.

5. The method of manufacturing a continuous flexible circuit board according to claim 4, wherein in the step of cleaning the substrate, the substrate is cleaned by automatically winding and unwinding the substrate by a horizontal microetching line, one end of the horizontal microetching line is a winding device, and the other end of the horizontal microetching line is a winding device, wherein the winding device is used for automatically winding the substrate in a roll shape so that the flat substrate flows into a horizontal microetching device, and the winding device is used for winding the flat substrate flowing out of the horizontal microetching device into a roll shape substrate.

6. The method for manufacturing a non-electroplating continuous flexible circuit board according to claim 5, wherein in the step of covering the front and back sides of the cleaned substrate with dry films to obtain the substrate with dry films on the front and back sides, the cleaned substrate is pressed with the films on the front and back sides by an automatic dry film sticking machine, the temperature of the automatic dry film sticking machine is set to 120-125 ℃, the film pressing speed is set to 2.5-3.5 m/min, wherein one end of the automatic dry film sticking machine is provided with the discharging device, and the other end of the automatic dry film sticking machine is provided with the receiving device.

7. The method for manufacturing a flexible circuit board according to claim 6, wherein the step of positioning and exposing the substrate having the dry films on the front and back surfaces by identifying the side holes is performed by placing the substrate having the dry films on the front and back surfaces into an exposure machine, wherein one end of the exposure machine is provided with the discharging device, and the other end of the exposure machine is provided with the receiving device.

8. The method for manufacturing a flexible circuit board according to claim 7, wherein in the step of sequentially etching and film-removing the exposed substrate to obtain the flexible circuit board with the metal line, the exposed substrate is placed in a horizontal DES line, and sequentially etching and film-removing are performed to obtain the flexible circuit board with the metal line, wherein one end of the horizontal DES line is provided with the discharging device, and the other end of the horizontal DES line is provided with the collecting device.

9. The method for manufacturing a non-electroplated continuous flexible circuit board according to claim 8, wherein the step of testing the flexible circuit board with the metal circuit and performing film pasting treatment on the flexible circuit board which is qualified in the test to obtain the flexible circuit board with the protective film comprises the following steps:

10. A non-electroplated continuous flexible circuit board prepared by the method of preparing a non-electroplated continuous flexible circuit board according to any one of claims 1-9.