CN114390787A - A manufacturing process of a flexible circuit board - Google Patents

Abstract

The invention discloses a manufacturing process of a flexible circuit board, which belongs to the technical field of flexible circuit boards. The manufacturing process of the flexible circuit board firstly performs laser cutting on one side of the outer layer board to form a reverse cutting groove, which effectively solves the problem that the inner layer board is easily cut due to the excessive laser cutting depth, which makes the flexible board scrapped and improves the flexibility. The production pass rate of the circuit board. The above-mentioned reverse cutting grooves are arranged in the pre-opening area of the flexible circuit board, and the pre-opening area that is not on the flexible circuit board will be laser cut on the other side of the outer layer board, which is conducive to removing waste materials and improving flexibility. Production efficiency of circuit boards.

Description

A manufacturing process of a flexible circuit board

technical field

The invention relates to the technical field of flexible circuit boards, in particular to a manufacturing process of a flexible circuit board.

Background technique

Nowadays, flexible circuit boards are mostly made of LCP (Liquid Crystal Polymer, liquid crystal polymer) materials as the base material. The LCP material has good heat and chemical resistance and its linear expansion rate is small, which makes the flexible circuit board meet the requirements of surface mount soldering technology for its dimensional stability and heat resistance. However, the flexibility of the LCP material is poor. In order to ensure the flexibility of the flexible circuit board, the flexible circuit board needs to be partially opened.

The production process of the flexible circuit board is as follows: firstly, the adhesive glue in the pre-opened area of the inner layer board is punched out, and the circuit is etched on the inner layer board at the same time; plywood; then etch the circuit on the outer surface of the plywood, and attach an outer protective film; after the surface treatment of the plywood with the outer protective film attached, open the cover by laser cutting; finally remove the waste to obtain a flexible circuit board .

However, the opening process of the above-mentioned flexible circuit board manufacturing process has the following defects:

1. Due to the poor flatness of the outer surface of the flexible circuit board, it is difficult to control the cutting depth during the laser cutting process, and it is easy to cut the inner layer board, making the flexible circuit board scrapped. Some data show that the defective rate of scrapped flexible circuit boards is as high as 30% due to difficult control of cutting depth.

2. When the above-mentioned cover opening process only cuts the cover opening area on the flexible circuit board, and part of the cover opening area is outside the flexible circuit board, it is not effectively cut. Cutting only a portion of the flexible circuit board will make it difficult to remove production waste and reduce the production efficiency of the flexible circuit board.

Therefore, there is an urgent need to provide a manufacturing process of a flexible circuit board to solve the above problems.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a manufacturing process of a flexible circuit board, solve the problem that the laser cutting depth of the cover opening in the existing flexible circuit board manufacturing process is not easy to control, and the problem that the cover opening cutting is only aimed at the flexible circuit board, and improve the flexibility of the flexible circuit board. production qualification rate and production efficiency.

To achieve the above purpose, the following technical solutions are provided:

A manufacturing process of a flexible circuit board, comprising the following steps:

S1, etch the inner layer circuit on the inner layer board, and remove the glue layer from the pre-opening area on the inner layer board;

S2, performing laser cutting on the pre-opened area on the flexible circuit board on one side of the outer layer board to form a reverse cutting groove;

S3. The outer-layer board and the inner-layer board are stacked in sequence from top to bottom to form a laminated board; and the side of the outer-layer board with the back-cut notch is in contact with the inner-layer board touch;

S4, etching the outer layer circuit on the outer layer board;

S5, pressing protective films on the upper and lower sides of the pressing plate;

S6, performing surface treatment on the window pads of the protective film on the outer layer board;

S7, performing laser cutting on the pre-opened area not on the flexible circuit board on the side of the outer-layer board where the outer-layer circuit is provided;

S8, after removing the waste material, to generate the flexible circuit board.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, both the inner layer board and the outer layer board include a base material layer and a copper layer provided on one side of the base material layer, and the inner layer circuit The outer layer circuit is arranged on the copper layer of the inner layer board, and the outer layer circuit is arranged on the copper layer of the outer layer board.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, the depth of laser cutting, the number of times of laser cutting, and the direction of laser cutting in step S2 are all determined by the thickness of the base material layer of the outer layer board.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, step S2 further includes the following steps:

S21. When the thickness of the base material layer of the outer layer board is not greater than 25 μm, laser cutting the pre-opened area on the flexible circuit board on one side of the outer layer board to form the reverse grooving;

S22. When the thickness of the base material layer of the outer layer board is not less than 50 μm, first perform laser cutting on the pre-opened area on the flexible circuit board on one side of the outer layer board to forming the reverse cutting groove; and then performing laser cutting on the pre-opened area on the flexible circuit board on the other side of the outer layer board to form a forward cutting groove.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, it includes: the depth of laser cutting in step S21 is the thickness of the base material layer of the outer layer board.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, the depths of the two laser cuttings in step S22 are both half of the thickness of the base material layer of the outer layer board.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, step S23 is also provided before step S21: opening a through hole along the thickness direction of the outer layer board; using the through hole as the back-cut slot and the Benchmark for laser cutting of tangential grooves.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, the depth of laser cutting in step S5 is not less than the thickness of the base material layer of the outer layer board.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, the boundary of the degummed area of the inner layer board is outwardly expanded relative to the boundary of the pre-opened cover area.

As an optional solution of the above-mentioned manufacturing process of the flexible circuit board, the distance between the boundary of the degummed area of the inner layer board and the boundary of the pre-opened cover area is 0.15 mm.

Compared with the prior art, the beneficial effects of the present invention:

The manufacturing process of a flexible circuit board provided by the present invention effectively solves the problem that due to the excessive laser cutting depth, the inner layer board is easily cut, and the flexible board is scrapped by performing laser cutting on one side of the outer layer board to form a reverse groove problems, and improve the production qualification rate of flexible circuit boards. The above-mentioned reverse cutting groove is arranged in the pre-opening area of the flexible circuit board, and the pre-opening area that is not on the flexible circuit board will be laser cut on the other side of the outer layer board, which is conducive to removing waste materials and improving flexibility. Production efficiency of circuit boards.

Description of drawings

1 is a flowchart of a manufacturing process of a flexible circuit board in an embodiment of the present invention;

Fig. 2 is the flow chart of step S2 in the embodiment of the present invention;

3 is a schematic diagram of opening the cover when the thickness of the substrate layer is not greater than 25 μm in the embodiment of the present invention;

FIG. 4 is a schematic diagram of opening the cover when the thickness of the substrate layer is not less than 50 μm in the embodiment of the present invention.

Reference number:

1. Inner board; 2. Outer board; 3. Adhesive layer; 4. Protective film;

21. Substrate layer; 22. Copper layer; 23. Reverse cut groove; 24, Normal cut groove; 25, Through hole.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Thus, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or The positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed when it is used. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the device referred to. Or elements must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first", "second", "third", etc. are only used to differentiate the description and should not be construed as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should also be noted that, unless otherwise expressly specified and limited, the terms "arrangement" and "connection" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection, or Integrally connected; either mechanical or electrical. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may include the first and second features in direct contact, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present invention, and should not be construed as a limitation of the present invention.

As shown in FIG. 1 to FIG. 4 , this embodiment provides a manufacturing process of a flexible circuit board, including the following steps:

S1. Etch the inner layer circuit on the inner layer board 1, and remove the adhesive layer 3 from the pre-opened area on the inner layer board 1;

S2, laser cutting the pre-opened area on the flexible circuit board on one side of the outer layer board 2 to form the reverse cutting groove 23;

S3, the outer layer board 2 and the inner layer board 1 are stacked sequentially from top to bottom to form a pressed board; and the side of the outer layer board 2 that is provided with the back-cut groove 23 is in contact with the inner layer board 1;

S4, etching the outer layer circuit on the outer layer board 2;

S5. Press the protective film 4 on the upper and lower sides of the pressing plate to protect the pressing plate from being in direct contact with the outside world;

S6. Surface treatment is performed on the window pads of the protective film 4 on the outer layer board 2 to ensure the solderability of the exposed pads, so as to facilitate the connection between the flexible circuit board and other electrical components;

S7, on the side of the outer layer board 2 where the outer layer circuit is provided, perform laser cutting on the pre-opened area that is not on the flexible circuit board;

S8, after removing the waste material, to generate the flexible circuit board.

The above-mentioned manufacturing process of the flexible circuit board firstly performs laser cutting on one side of the outer layer board 2 to form the reverse cutting groove 23, which effectively solves the problem that the inner layer board 1 is easily cut due to the excessive laser cutting depth, and the flexible board is scrapped. The production qualification rate of the flexible circuit board is improved. The above-mentioned reverse cutting groove 23 is arranged in the pre-opening area of the flexible circuit board, and the pre-opening area that is not on the flexible circuit board will be laser cut on the other side of the outer board The production efficiency of flexible circuit boards is improved.

The inner layer board 1 and the outer layer board 2 both include a base material layer 21 and a copper layer 22 arranged on one side of the base material layer 21 , the inner layer circuit is arranged on the copper layer 22 of the inner layer plate 1 , and the outer layer circuit is arranged on the copper layer 22 of the inner layer board 1 . on the copper layer 22 of the outer layer board 2 .

Since the flexible circuit board will choose different thicknesses according to the application, the thickness of the base material in the flexible circuit board with different thicknesses is different, and the depth of laser cutting will also change accordingly when the cover is opened. Therefore, the depth of laser cutting, the number of times of laser cutting, and the direction of laser cutting in step S2 are all determined by the thickness of the base material layer 21 of the outer layer board 2 .

Further optionally, step S2 also includes the following steps:

S21, when the thickness of the base material layer 21 of the outer layer board 2 is not greater than 25 μm, perform laser cutting on the pre-opened area on the flexible circuit board on one side of the outer layer board 2 to form the reverse cutting groove 23;

S22. When the thickness of the base material layer 21 of the outer layer board 2 is not less than 50 μm, perform laser cutting on the pre-opened area on the flexible circuit board on one side of the outer layer board 2 to form a reverse cutting groove 23; On the other side of 2, the pre-opened area on the flexible circuit board is laser cut to form the tangent groove 24.

The above steps propose two cutting solutions according to the difference in the thickness of the base material layer 21 of the outer layer board 2 . When the base material layer 21 is relatively thin, cutting the reverse cutting groove 23 on the outer layer board 2 can realize the cutting of the pre-opened area on the flexible circuit board. Pre-cutting the reverse cutting groove 23 completely eliminates the defective rate of scrapping the flexible circuit board due to the difficult control of the cutting depth, and improves the production qualification rate of the flexible circuit board.

When the base material layer 21 is thick, cutting the reverse cutting groove 23 on one side of the outer layer board 2 and cutting the normal cutting groove 24 on the other side can not only realize the cutting of the pre-opening area on the flexible circuit board, but also improve the In the prior art, since the base material layer 21 is thick, it is necessary to perform laser cutting in the same direction for many times and for a long time, which leads to the problem of carbon black on the flexible circuit board, and improves the aesthetics of the flexible circuit board. Data shows that the manufacturing process of the flexible circuit board in this embodiment will reduce the defective rate of the flexible circuit board that is unqualified due to carbon black from 20% to 3%.

In order to improve the production quality of the flexible circuit board, further optionally, the depth of the laser cutting in step S21 is the thickness of the base material layer 21 of the outer layer board 2 . Further optionally, the depths of the two laser cuttings in step S22 are both half of the thickness of the base material layer 21 of the outer layer board 2 . Since the thickness of the existing substrate is only 25 μm and 50 μm, in this embodiment, in the laser cutting in step S2 , it is only necessary to control the cutting depth to be 25 μm.

In order to improve the accuracy of laser cutting, it is necessary to set the benchmark for laser cutting. Therefore, further optionally, step S23 is further provided before step S21 : opening through holes 25 along the thickness direction of the outer layer board 2 . Using the through hole 25 as the benchmark for the laser cutting of the reverse cutting groove 23 and the tangential cutting groove 24 can not only improve the accuracy of laser cutting, but also make the reverse cutting groove 23 and the regular cutting groove 24 on the same straight line, ensuring the consistency of the two cuts sex.

Further optionally, the laser cutting depth in step S5 is not less than the thickness of the base material layer 21 to ensure that the outer layer board 2 can be completely cut, which is convenient for subsequent waste removal.

Further optionally, the boundary of the degumming area of the inner layer board 1 is expanded outward relative to the boundary of the pre-opening area, so as to avoid the waste after cutting from sticking to the flexible circuit board, which is inconvenient to remove. In this embodiment, the boundary of the degumming area of the inner layer board 1 is outwardly expanded by 0.15 mm relative to the boundary of the pre-opening area.

Further optionally, in step S1, the method of punching is selected to remove the glue, which improves the efficiency of the glue removal.

Further optionally, the surface treatment in step S6 is performed by a gold chemical process or an OSP (Organic Solderability Preservatives, organic solder protection film) process.

Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention. The scope is determined by the scope of the appended claims.

Claims (10)

1. a manufacturing process of a flexible circuit board, is characterized in that, comprises the following steps: S1, etching the inner layer circuit on the inner layer board (1), and removing the adhesive layer (3) from the pre-opened area on the inner layer board (1); S2, performing laser cutting on the pre-opened area on the flexible circuit board on one side of the outer layer board (2) to form a reverse cutting groove (23); S3. The outer layer board (2) and the inner layer board (1) are stacked sequentially from top to bottom to form a laminated board; and the outer layer board (2) is provided with the reverse cutting groove (23) One side of the notch is in contact with the inner layer board (1); S4, etching the outer layer circuit on the outer layer board (2); S5, pressing the protective film (4) on the upper and lower sides of the pressing plate; S6, performing surface treatment on the window pads of the protective film (4) on the outer layer board (2); S7, performing laser cutting on the pre-opened area not on the flexible circuit board on the side of the outer-layer board (2) where the outer-layer circuit is provided; S8, after removing the waste material, to generate the flexible circuit board. 2. The manufacturing process of the flexible circuit board according to claim 1, characterized in that both the inner layer board (1) and the outer layer board (2) comprise a base material layer (21) and a base material layer (21) provided on the base material. A copper layer (22) on one side of the layer (21), the inner layer circuit is arranged on the copper layer (22) of the inner layer board (1), and the outer layer circuit is arranged on the outer layer board (2) on the copper layer (22). 3. The manufacturing process of the flexible circuit board according to claim 2, wherein in step S2, the depth of laser cutting, the number of times of laser cutting, and the direction of laser cutting are determined by the base material of the outer layer board (2). Layer (21) thickness is determined. 4. The manufacturing process of the flexible circuit board according to claim 3, wherein step S2 further comprises the following steps: S21. When the thickness of the base material layer (21) of the outer layer board (2) is not greater than 25 μm, align the pre-fab on the flexible circuit board on one side of the outer layer board (2). Laser cutting is carried out in the open area to form the reverse cutting groove (23); S22. When the thickness of the base material layer (21) of the outer layer board (2) is not less than 50 μm, first align the substrate layer (21) on the flexible circuit board on one side of the outer layer board (2). Perform laser cutting on the pre-opened area to form the reverse cutting groove (23); and then perform laser cutting on the pre-opened area on the flexible circuit board on the other side of the outer layer board (2) , to form a tangential groove (24). 5 . The manufacturing process of the flexible circuit board according to claim 4 , wherein the depth of laser cutting in step S21 is the thickness of the base material layer ( 21 ) of the outer layer board ( 2 ). 6 . 6 . The manufacturing process of the flexible circuit board according to claim 4 , wherein the depth of the two laser cuts in step S22 is half the thickness of the base material layer ( 21 ) of the outer layer board ( 2 ). 7 . 7. The manufacturing process of the flexible circuit board according to claim 4, wherein a step S23 is further provided before the step S21: opening a through hole (25) along the thickness direction of the outer layer board (2); The hole (25) serves as a reference for the laser cutting of the reverse cut groove (23) and the tangential groove (24). 8 . The manufacturing process of the flexible circuit board according to claim 1 , wherein the depth of laser cutting in step S5 is not less than the thickness of the base material layer ( 21 ) of the outer layer board ( 2 ). 9 . 9 . The manufacturing process of the flexible circuit board according to claim 1 , wherein the boundary of the degumming area of the inner layer board ( 1 ) expands outward relative to the boundary of the pre-opened cover area. 10 . 10 . The manufacturing process of the flexible circuit board according to claim 9 , wherein the distance between the boundary of the degummed area of the inner layer board ( 1 ) and the boundary of the pre-opened cover area is 0.15 mm. 11 .

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