CN114302570A

CN114302570A - Etching circle manufacturing method based on FPC

Info

Publication number: CN114302570A
Application number: CN202210020835.8A
Authority: CN
Inventors: 胡井海; 张伟; 李绪东; 虞成城
Original assignee: Sunway Communication Jiangsu Co Ltd
Current assignee: Sunway Communication Jiangsu Co Ltd
Priority date: 2022-01-10
Filing date: 2022-01-10
Publication date: 2022-04-08

Abstract

The invention discloses a manufacturing method of an etching circle based on an FPC (flexible printed circuit), wherein a waste area is fully paved with a circle with the diameter of 1mm, a product graph and an identification mark are placed, the process is completed on a film negative film at one time, the product graph is transferred on a dry film of a copper foil through exposure, the dry film is attached to the surface of a processing surface of the copper foil, the etching circle and the product graph appear on a product area through a process flow, the FPC is formed by arranging a plurality of product areas, the FPC comprises a product effective area and a product waste area, the product area is arranged in the product effective area, the product waste area is provided with uniformly distributed etching circles, a copper-free area is arranged between the product effective area and the product waste area, copper in the product waste area around the copper-free area is not less than 0.4mm, and the distance between the etching circles and a positioning target hole is not less than 5 mm. According to the invention, the etching circle is added in the waste area of the product, so that the problem of line corrugation caused by manual taking of the product is reduced, the expansion and shrinkage stability of the FPC is improved, and the yield of the product is improved.

Description

Etching circle manufacturing method based on FPC

Technical Field

The invention relates to the technical field of flexible circuit boards, in particular to an etching circle manufacturing method based on an FPC (flexible printed circuit).

Background

The FPC is a flexible printed circuit board made of Polyimide (PI) or polyester film as a base material, has high reliability and excellent flexibility, has the characteristics of high wiring density, light weight, thin thickness and good bending property, and is used in products of a plurality of enterprises, and the outlines of the FPCs are widely different. Currently, PI materials are too hygroscopic, resulting in reduced reliability of FPCs made therefrom under high humidity conditions, including the hazards of oxidation of the copper foil and reduction in peel strength caused by evaporation of the water paint at high temperatures. Moreover, the FPC based on the PI material is only suitable for manufacturing high-frequency antennas with the frequency of less than 6 GHz. The use frequency is increasing with the high-frequency and high-speed development of the actuator, and for the high-frequency antenna with the frequency of more than 6GHz, the signal loss is large due to the high dielectric constant (3.4) and the high dielectric loss (0.02) of PI. Thus, a resin material having a low dielectric constant and low dielectric loss, such as a Liquid Crystal Polymer (LCP) material, has to be used.

In the prior art, due to the influence of thinner material, the FPC is manually taken after the circuit is formed and is influenced by stress, and wrinkles are easy to appear in an effective area of a product, so that the product is wrinkled and scrapped; after the product is formed on the circuit, the copper is irregular due to the fact that the whole board surface is reserved, in the RTR process, under the action of traction force of a machine table, the expansion and shrinkage are unstable, and the yield of the FPC and subsequent manufacturing are affected.

Disclosure of Invention

According to the technical problem to be solved, the method for manufacturing the etching circle based on the FPC is provided.

In order to achieve the purpose, the invention discloses an etching circle manufacturing method based on an FPC (flexible printed circuit). in the process of file manufacturing, a waste area is fully paved with a circle with the diameter of 1mm, a product graph and an identification mark are placed, then the process is completed on a film negative film at one time, the product graph is transferred on a copper foil dry film through exposure, the dry film is attached to the surface of a copper foil processing surface, the etching circle and the product graph appear on a product area together through a process flow, and the etching circle is designed for not leaving copper.

Further, the FPC board is arranged by the product region of a plurality of quantity and is constituteed, the FPC board includes product active area and product waste material district, the product region sets up in the product active area, the product waste material district is provided with the etching circle of evenly arranging, the product region is arranged by a plurality of product figure arrays and is constituteed, makes the stress of product region and whole FPC board obtain releasing, avoids the buckling phenomenon of crooked production.

Furthermore, the etching circles are copper-free circles with the diameter not larger than 1mm, the transverse spacing of the etching circles is 1.5mm, the longitudinal spacing of the etching circles is 1.5mm, and the uniformly arranged etching circles can release the stress of the product and maintain the structural integrity of a product waste area.

Furthermore, a copper-free area is arranged between the product effective area and the product waste area, copper is not less than 0.4mm reserved in the product waste area around the copper-free area, and the stability of the product can be guaranteed by the copper-reserved area.

Furthermore, a plurality of positioning target holes are formed in the FPC board, the distance between the etching circle and the positioning target holes is not smaller than 5mm, the positioning target holes are used for machine mark identification, and the distance between the positioning target holes and the etching circle can avoid machine identification errors.

Further, the process flow includes developing, etching, and stripping.

Furthermore, the FPC boards are stacked in the vertical direction, and the etching circles corresponding to two adjacent layers of FPC boards are staggered, so that the phenomenon of uneven thickness caused by the fact that the etching circles of different layers are stacked in the same position is avoided, and the thickness of the board is stabilized.

Compared with the prior art, the invention has the following beneficial effects: the etching circular structure is added in the product waste area, so that the stress of the whole product is released, the problem of circuit buckling caused by manual taking in the product effective area is reduced, the expansion and shrinkage stability of the FPC is improved, and the product yield is improved; meanwhile, the etching circle structure can be formed together with the circuit, so that the cost is not increased.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Fig. 1 is a schematic structural diagram of an FPC board according to the prior art.

Fig. 2 is a schematic structural diagram of an FPC-based etched circle structure according to an embodiment of the present invention.

Fig. 3 is a partial enlarged view a of the first embodiment of the present invention.

Fig. 4 is a schematic diagram of an etched circle of adjacent FPC boards according to the third embodiment of the present invention.

Fig. 5 is a sectional view of a third embodiment of the present invention.

FIG. 6 shows the results of the prior art FPC board four-side expansion and contraction rate test.

FIG. 7 shows the results of testing the four-side shrinkage of the FPC board with the etched circle structure according to the present invention.

FIG. 8 is a process flow diagram of the present invention.

In the figure: 1 is an FPC board; 2 is a product area; 3 is a positioning target hole; 4 is a copper-free area; 5 is an etching circle; 11 is a product effective area; 12 is a product waste area; and 21, product graphics.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of the present invention.

The first embodiment of the invention provides a manufacturing method of an etching circle structure based on an FPC (flexible printed circuit), as shown in fig. 1 and fig. 2, fig. 1 is a schematic diagram of a structure of the FPC in the prior art, fig. 2 is a schematic diagram of the structure of the FPC in the invention, a circle with the diameter of 1mm is fully paved in a waste area of a film negative, a product graph 21 and an identification mark are placed, the product graph 21 is transferred to a dry film of a copper foil through exposure, the dry film is attached to the surface of a processing surface of the copper foil, and finally, an etching circle 5 and the product graph 21 appear on a product area 2 together through the process flows of developing, etching and stripping, and the etching circle 5 is designed without copper.

In the second embodiment, as shown in fig. 3, an etching circle structure based on FPC of the present invention is disclosed, wherein a copper-free area 4 is disposed at an edge of a product active area 11, the copper-free area 4 is disposed between the product active area 11 and a product waste area 12, copper is not less than 0.4mm remained in the product waste area 12 around the copper-free area 4, and the etching circle 5 is not placed within a range of 5mm around a positioning target hole 3.

In the third embodiment, as shown in fig. 4 and 5, the FPC boards 1 are stacked in the vertical direction, and the positions of the etching circles 5 corresponding to two adjacent layers of FPC boards are staggered, taking four layers of boards as an example, which are respectively L1, L2, L3, and L4, wherein L1 and the etching circles 5 in L2 are transversely and longitudinally arranged at equal intervals, and since the etching circles 5 are designed without copper, the position of the etching circle 5 of the upper layer FPC board L1 corresponds to the position of the non-etching circle 5 of the lower layer FPC board L2, the position of the etching circle 5 of L3 is the same as L1, and the position of the etching circle 5 of L4 is the same as L2, so as to achieve different layers of staggered placement, and finally stabilize the board thickness.

The FPC boards of the first embodiment are respectively subjected to a harmomegathus test, where X1 is the upper side of the FPC board, X2 is the lower side of the FPC board, Y1 is the right side of the FPC board, and Y2 is the left side of the FPC board, and according to the test results, as shown in fig. 6 and 7, the maximum value and the minimum value of the harmomegathus of the FPC boards Y1 and Y2 in the prior art are different more, which indicates that the harmomegathus effect is not good, but the etched circle structure adopted by the present invention can improve the harmomegathus phenomenon of the FPC boards.

The points to be explained are as follows: first, in the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounted," "connected," and "connected" should be understood broadly, and may be a mechanical connection or an electrical connection, or a communication between two elements, and may be a direct connection, and "upper," "lower," "left," and "right" are only used to indicate a relative positional relationship, and when the absolute position of the object to be described is changed, the relative positional relationship may be changed; second, in this document, relational terms such as first and second, and the like may be used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities.

The above examples are merely illustrative of the present invention and should not be construed as limiting the scope of the present invention, and all designs identical or similar to the present invention are within the scope of the present invention.

Claims

1. A manufacturing method of an etching circle based on FPC is characterized in that:

s1: in the file manufacturing, a waste material area is fully paved with a circle with the diameter of 1mm, then a product graph (21) and an identification mark are placed, and the file manufacturing is finished on a film negative film at one time;

s2: transferring a product graph (21) on a copper foil dry film through exposure, wherein the dry film is attached to the surface of a copper foil processing surface;

s3: by means of the process flow, an etching circle (5) is present on the product area together with the product pattern (21), said etching circle (5) being designed without leaving copper.

2. The FPC-based etched circle manufacturing method according to claim 1, wherein: FPC board (1) is arranged by the product region (2) of a plurality of quantity and is constituteed, FPC board (1) is including product active area (11) and product waste material district (12), product region (2) set up in product active area (11), product waste material district (12) are provided with etching circle (5) of evenly arranging, product region (2) are arranged by a plurality of product figure (21) array and are constituteed.

3. The FPC-based etched circle manufacturing method according to claim 2, wherein: the etching circle (5) is a copper-free circle with the diameter not larger than 1mm, the transverse distance of the etching circle (5) is 1.5mm, and the longitudinal distance of the etching circle (5) is 1.5 mm.

4. The FPC-based etched circle manufacturing method according to claim 2, wherein: a copper-free area (4) is arranged between the product effective area (11) and the product waste area (12), and copper remained in the product waste area (12) around the copper-free area (4) is not less than 0.4 mm.

5. The FPC-based etched circle manufacturing method according to claim 2, wherein: the FPC board (1) is provided with a plurality of positioning target holes (3), and the distance between the etching circle (5) and the positioning target holes (3) is not less than 5 mm.

6. The FPC-based etched circle manufacturing method according to claim 1, wherein: the process flow comprises developing, etching and stripping.

7. The FPC-based etched circle manufacturing method according to claim 1, wherein: the FPC boards (1) are stacked in the vertical direction, and the positions of the etching circles (5) corresponding to the two adjacent layers of FPC boards (1) are arranged in a staggered mode.