JP2022128059A - Substrate for double-sided and multi-layer fpc and processing method thereof - Google Patents

Abstract

To reduce production costs, facilitate the formation of holes, and easily allow sputtering on the inner surfaces of the holes, and avoid sputtering to the opposing roll by sputtering the sputtering plasma onto the inner surfaces of the holes.SOLUTION: The present invention relates to a technical field of processing a substrate, and more particularly to a substrate for double-sided and multi-layer FPCs and a processing method thereof. The substrate for the double-sided and multi-layer FPC includes a base material having a plurality of inclined holes penetrating in a thickness direction, a sputtering layer attached to the base material and the surfaces of the inclined holes, a conductive portion provided in the inclined hole and connected to the sputtering layer, and a plurality of line copper layers located on the upper and lower surfaces of the base material and connected to the sputtering layer, and in which the plurality of line copper layers are connected by the conductive portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to the technical field of processing substrates, and more particularly to substrates for double-sided and multi-layer FPCs and processing methods thereof.

A flexible printed circuit board (FPC) is manufactured using a thin film of polyimide or polyester as a base material, and is a printed circuit board with high reliability and excellent flexibility. It is simply called FPC, and has characteristics such as high wiring density, light weight, and thin thickness.

COF (Chip On Flex, or Chip On Film, often called crystal coated film), a technology to fix the driving IC on the flexible circuit board and package it with a crystal grain flexible film, uses an additional circuit board as a flexible It is a technology that combines a chip and a flexible substrate circuit as a carrier for a chip package. COF is one type of FPC that requires relatively high accuracy.

When manufacturing double-sided and multi-layer FPCs by conventional methods, the following two methods are adopted.
1. The build-up method includes the steps of conductive hole drilling, hole cleaning, black shadow, lamination, exposure, projection, copper plating, film removal, bottom copper removal, tiecoat removal and circuit inspection in sequence. .
2. Etching method The engineering method includes the steps of conductive hole drilling, hole cleaning, black shadow, copper plating, lamination pretreatment, lamination, exposure, projection, etching, film removal and circuit inspection in sequence. is

The prior art often purchases an FPC substrate covered with copper foil and installs vertical conductive holes. On the other hand, the cost of the FPC base material covered with copper foil is higher than that of the insulating film base material. The demand for light energy is increasing, the efficiency of hole placement is low, and the FPC substrate covered with copper foil is distorted due to overheating, increasing the error.

In addition, when a hole is provided as a vertical hole in the insulating film base material, if sputtering is performed through the vertical hole, it is difficult to completely cover the inner surface of the vertical hole with the sputtering layer, and moreover, sputtering is performed using the vertical hole. Then, the sputtering plasma will pass through the vertical hole and sputter to the opposite roll, causing the roll to stick, and the sticking sputtering plasma will fall down and form powder, leading to contamination. .

The problem to be solved by the present invention is that, in the prior art, if the FPC substrate covered with copper foil is purchased and holes are installed, the cost is high and it is difficult to install the holes. 2, when the vertical hole is installed, the technical problem is that it is difficult to completely cover the hole with the sputtering layer, and the sputtering plasma passes through the vertical hole and sputters to the opposite roll, causing the roll to stick. It's about solving technical problems.
According to the double-sided and multi-layer FPC substrate processing method provided by the present invention, the production cost can be reduced, the difficulty of hole installation can be reduced, and the inner surface of the convenient hole can be easily sputtered, Also, by sputtering the sputtering plasma up to the inner surface of the hole, it is possible to avoid sputtering the opposing roll.

The present invention provides a technical means for solving the above-described problems, comprising a base material having a plurality of inclined holes penetrating in the thickness direction, and a sputtering layer attached to the surface of the base material and the inclined holes. a conductive portion provided in the inclined hole and connected to the sputtering layer; and a plurality of line copper layers positioned on upper and lower surfaces of the base material and connected to the sputtering layer, wherein the plurality of line copper layers are spaced apart from the A substrate for double-sided and multi-layer FPC, comprising a plurality of line copper layers connected by conductive portions.

Preferably, the slanted hole is a cylindrical slanted hole.

The orthographic projection of the upper opening of the slanted hole and the orthographic projection of the lower opening of the slanted hole do not intersect, and the straight line distance between the orthographic projection of the upper opening and the orthographic projection of the lower opening is the orthographic projection of the upper opening. Not greater than the longest chord of the projection.
Since the orthographic projection of the upper opening of the oblique hole and the orthographic projection of the lower opening of the oblique hole do not intersect, the sputtering plasma cannot directly pass through the upper opening and the lower opening when the sputtering plasma is vertically sputtered. , which can solve the technical problem of further avoiding the sputtering plasma from sputtering through the hole to the opposing roll. Moreover, the linear distance between the orthographic projection of the upper aperture and the orthographic projection of the lower aperture is no greater than the longest chord of the orthographic projection of the upper aperture. If the linear distance between the orthographic projection of the upper opening and the orthographic projection of the lower opening is greater than the longest chord of the orthographic projection of the upper opening, then the effective area for sputtering the sputtering plasma onto the inner wall of the inclined hole is It may become smaller, and it may not be possible to ensure electrical continuity in the slanted hole in the subsequent plating process.

The orthographically projected edge of the upper opening of the inclined hole and the orthographically projected edge of the lower opening of the inclined hole are tangential. If the orthographically projected edge of the upper opening of the angled hole and the orthographically projected edge of the lower opening of said angled hole are tangential, the sputtering plasma cannot sputter from within the angled hole to the opposing roll and will not be able to sputter from the upper opening. It can ensure that the generated sputtering plasma is just and completely sputtered to the inner surface of one side of the inclined hole, so that the distribution effect of sputtering in the hole is further improved.

Preferably, the substrate is a PI film. The PI film has excellent high temperature resistance, low temperature resistance, electrical insulation, adhesiveness, radiation resistance, and chemical resistance.

Any one of the above-described methods for processing a substrate for double-sided and multilayer FPC includes a step S1 of forming an inclined hole penetrating in a thickness direction in the surface of the base material, a step S2 of cleaning the inclined hole, and a step S3 of sputtering a sputtering layer on the inner surface of the inclined hole and both surfaces of the base material; plating the base material and the inclined hole to thicken the material; and a step S4 of covering a plurality of line copper layers on the surface of the material and conducting between the plurality of line copper layers through the conductive portions.

A method of processing a substrate for double-sided and multilayer FPC according to the present application provides inclined holes in the thickness direction of a base material. Since there is no copper foil or copper layer on the base material, the purchase cost is low and holes can be easily formed. It is possible to avoid the fact that the efficiency of hole setting is lowered, the base material is distorted due to overheating, and the error is increased. After cleaning the angled hole, the inner surface of the angled hole and the substrate are sputtered on both sides thereof. Since the hole is an inclined hole, when sputtering is performed, the inner surface of the inclined hole is inclined. is more likely to adhere to the surface of the base material, and if the inner surface of the slanted hole is in a slanted state, it becomes even more difficult for the sputtering plasma to directly pass through the hole and sputter to the opposing roll.

In order to achieve uniform distribution of the metal sputtering plasma on the inner wall of the positioning hole, in step S3, a part of the inner wall of the slanted hole and one side of the substrate are simultaneously sputtered with a part of the sputtering layer. , the other part of the sputtering layer is simultaneously sputtered onto the other part of the inner wall of the inclined hole and the other surface of the substrate.

In step S4, the inner walls of the inclined holes and both surfaces of the substrate are plated simultaneously so as to make the plating layer uniform.

Preferably, in step S2, the angled holes are cleaned with Plasma or Desmear.

Preferably, in step S1, the inclined holes are formed by laser light.

The beneficial effects of the double-sided and multi-layered FPC substrate and its processing method according to the present invention are as follows.
1. Since there is no metal layer on the base material, the cost is low, the energy used to form holes with laser light is low, the speed and efficiency of hole formation are high, the amount of heat is small, and the amount of distortion in the base material is small. , the accuracy is relatively high.
2. Since the sputtering is performed through the inclined holes, the distribution effect of the sputtering is improved in the holes, and the sputtering plasma passes through the inclined holes to the facing rolls, thereby avoiding sticking of the rolls and making the rolls adhere to each other. It is possible to avoid contamination by powders that fall off and form.

In the following, the invention will be explained in detail with reference to the drawings and examples.
1 is a schematic diagram of a first embodiment of a double-sided and multi-layer FPC substrate according to the present invention; FIG. FIG. 2 is a schematic diagram of a second embodiment of a double-sided and multi-layer FPC substrate according to the present invention; FIG. 4 is a schematic diagram of an orthographic projection of upper and lower openings of inclined holes in the method of processing a double-sided and multi-layer FPC substrate according to the present invention; 1 is a schematic diagram of a cross-sectional configuration of a double-sided and multilayer FPC substrate according to the present invention; FIG.

The present invention will be described in more detail below with reference to the drawings. Since these drawings are simplified schematic diagrams and are intended to exemplify the basic configuration of the present invention, only the structure according to the present invention is shown.

As shown in FIG. 1, a double-sided and multi-layer FPC board according to the first embodiment of the present invention comprises a substrate 10 having a plurality of oblique holes 11 penetrating in the thickness direction, and a substrate 10. The sputtering layer 1 attached to the surface of the inclined hole 11, the conductive part located in the inclined hole 11 and connected to the sputtering layer 1, and the plurality of lines located on the upper and lower surfaces of the substrate 10 and connected to the sputtering layer 1. The copper layer 2 includes a plurality of line copper layers 2 in which the plurality of line copper layers 2 are connected by conductive portions.
The inclined hole 11 is a cylindrical inclined hole. The orthographic projection of the upper opening 12 of the slanted hole 11 and the orthographic projection of the lower opening 13 of the slanted hole 11 do not intersect, and the linear distance between the orthographic projection of the upper opening 12 and the orthographic projection of the lower opening 13 is the upper opening 12 not greater than the longest chord of the orthographic projection of . A base material 10 is a PI film.

The orthographic projection of the upper opening 12 of the slanted hole 11 and the orthographic projection of the lower opening 13 of the slanted hole 11 do not intersect, and the linear distance between the orthographic projection of the upper opening 12 and the orthographic projection of the lower opening 13 is the upper opening 12 , if not greater than the longest chord of the orthographic projection of the upper aperture 12, as shown in FIGS. If the length is also L, and the linear distance between the orthographic projection of the upper opening 12 and the orthographic projection of the lower opening 13 is d, then 0<d≦L, and the sputtering plasma is completely formed in the inclined hole 11 during sputtering. Although the inner surface cannot be sputtered, both sides of the base material 10 can be made conductive by filling the inner surface of the inclined hole 11 with plating in a subsequent plating process.

Beneficial effects of the first embodiment are as follows.

For the substrate for double-sided and multi-layer FPC according to the present application, the substrate 10 is provided with oblique holes 11 in its thickness direction. Since there is no copper foil or copper layer on the base material, the purchase cost is low and hole placement is simple. In addition, the use of a copper foil or copper layer requires high energy requirements for the laser beam, and the efficiency of drilling holes is low. After cleaning the inclined hole, both the inner surface of the inclined hole and the base material are sputtered. When an inclined state is formed and sputtering is performed, the sputtering plasma is likely to be sputtered to the inner surface of the inclined hole, and the sputtering plasma is more likely to adhere to the surface of the base material. are difficult to sputter directly through the hole to the opposing roll.

As shown in FIG. 2, the double-sided and multi-layer FPC board according to the second embodiment of the present invention differs from that according to the first embodiment in that the upper opening 12 of the inclined hole 11 is different. The orthographically projected edge and the orthographically projected edge of the lower opening 13 of the inclined hole 11 are tangential.

Beneficial effects of the second embodiment are as follows.
When the orthographically projected edge of the upper opening 12 of the angled hole 11 and the orthographically projected edge of the lower opening 13 of the angled hole 11 are tangential, the sputtering plasma cannot sputter from within the angled hole to the opposing roll, and the sputtering plasma exits the upper opening 12. It can ensure that the generated sputtering plasma is just completely sputtered on the inner surface of one side of the inclined hole, so that the sputtering distribution effect in the hole is further improved.

The method for processing the substrate for double-sided and multi-layer FPC according to the above two embodiments includes the following steps.

In step S1, an inclined hole 11 penetrating in the thickness direction is formed in the surface of the base material 10 . In addition, the inclined hole 11 is formed by a laser beam.

A step S2 cleans the slanted hole 11 . Further, in step S2, the inclined holes 11 are cleaned with Plasma or Desmear.

Step S3 sputters a conductive layer on the inner surface of the slanted hole 11 and both surfaces of the substrate 10 . In step S3, a conductive layer is simultaneously sputtered on a portion of the inner wall of the inclined hole 11 and one surface of the substrate 10, and a conductive layer is simultaneously sputtered on the other portion of the inner wall of the inclined hole 11 and the other surface of the substrate 10. do.

In step S4, the substrate 10 is plated to be thickened so that the surface of the substrate 10 is covered with the line copper layer and both surfaces are electrically connected. In step S4, the inner wall of the inclined hole 11 and both surfaces of the substrate 10 are simultaneously plated.

As described above, the double-sided and multi-layer FPC substrate and the processing method thereof according to the present invention have no metal layer on the base material 10, so that the cost is low and the energy for forming holes by laser light is low. , the speed and efficiency of hole formation is high, the amount of heat is small, the distortion of the substrate is small, and the accuracy is relatively high. In addition, by performing sputtering through the inclined holes 11, the effect of sputtering is improved, and sputtering plasma penetrates through the inclined holes and sputters to the facing rolls, thereby avoiding sticking of the rolls, which is becoming sticky. This makes it possible to avoid contamination by falling powder.

The preferred embodiment of the present invention described above is suggestive, and based on the above description and content, a person skilled in the art can make numerous changes and modifications without departing from the scope of the technical spirit of the present invention. It is clear that it is possible to obtain It goes without saying that the scope of protection of the present invention is not limited to what is described in the specification, and the technical scope is defined based on the claims.

Reference Signs List 1 Sputtering layer 2 Line copper layer 10 Base material 11 Inclined hole 12 Upper opening 13 Lower opening

Claims (10)

a base material (10) provided with a plurality of inclined holes (11) penetrating in the thickness direction;
a sputtering layer (1) attached to the surface of the substrate (10) and the oblique hole (11);
a conductive part provided in the inclined hole (11) and connected with the sputtering layer (1);
A plurality of line copper layers (2) located on the upper and lower surfaces of the substrate (10) and connected to the sputtering layer (1), wherein the plurality of line copper layers (2) are connected by the conductive portion. A substrate for double-sided and multi-layer FPC, comprising: a plurality of line copper layers (2). The substrate for double-sided and multi-layer FPC according to claim 1, characterized in that said slanted hole (11) is a cylindrical slanted hole. The orthographic projection of the upper opening (12) of the inclined hole (11) and the orthographic projection of the lower opening (13) of the inclined hole (11) do not intersect, and the orthographic projection of the upper opening (12) and the lower opening (13) do not intersect. 3. The substrate for double-sided and multi-layer FPC according to claim 2, characterized in that the linear distance between the orthographic projection of (13) is not greater than the longest chord of the orthographic projection of said upper opening (12). 2. The edge of the orthographic projection of the upper opening (12) of the inclined hole (11) and the edge of the orthographic projection of the lower opening (13) of the inclined hole (11) are tangential. 2. The substrate for double-sided and multi-layer FPC according to 2 above. The substrate for double-sided and multi-layer FPC according to claim 1, characterized in that said substrate (10) is a PI film. A method for processing a double-sided and multi-layer FPC substrate according to any one of claims 1 to 5,
step S1 of forming an inclined hole (11) penetrating in the thickness direction in the surface of the base material (10);
a step S2 of cleaning said inclined hole (11);
a step S3 of sputtering a sputtering layer (1) on the inner surface of the slanted hole (11) and both sides of the substrate (10);
The base material (10) and the slanted hole (11) are plated to thicken, forming a conductive part in the slanted hole (11), and a plurality of line copper wires on the surface of the base material (10). and a step S4 of covering the layer (2) and establishing electrical continuity between the plurality of line copper layers (2) via the conductive portions. In step S3, a part of the inner wall of the inclined hole (11) and one surface of the base material (10) are simultaneously sputtered as a part of the sputtering layer (1), and other than the inner wall of the inclined hole (11) 7. The processing method according to claim 6, wherein the part and the other surface of the substrate (10) are simultaneously sputtered as the other part of the sputtering layer (1). 7. The processing method according to claim 6, wherein in step S4, the inner wall of said inclined hole (11) and both surfaces of said substrate (10) are simultaneously plated. 7. The processing method according to claim 6, wherein in step S2, said inclined hole (11) is cleaned by plasma or desmear. 7. The processing method according to claim 6, wherein in step S1, said inclined hole (11) is formed by laser light.

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