KR20180025345A - Rigid flexible circuit board manufacturing method - Google Patents

Abstract

The present invention relates to a method for manufacturing a rigid flexible circuit board, which comprises the steps of: a) preparing a base layer and a plurality of core layers having an inner layer circuit formed on a surface thereof; b) preparing a prepreg layer having a plurality of through holes formed at regular intervals to correspond to a flexible region of the core layers; c) forming an inner layer circuit board by stacking each of the core layers on upper and lower portions of the base layer with the base layer as a center, and stacking the prepared prepreg layer on the core layers stacked on the upper portion of the base layer among the core layers; d) performing hot-press while stacking an outer layer insulating layer, which is bonded to a surface of a copper foil, on upper and lower surfaces of the inner layer circuit board; e) etching the copper foil of the outer layer insulating layer to form an outer layer circuit on the outer layer insulating layer; and f) completing a rigid flexible circuit board by removing a substrate dummy positioned in the flexible region in either upward or downward direction with respect to the prepreg layer of the circuit board. Accordingly, interlaminar adhesion of the circuit board and flexibility of the flexible region are improved.

Description

Technical Field [0001] The present invention relates to a rigid flexible circuit board manufacturing method,

The present invention relates to a rigid flexible circuit board manufacturing method, and more particularly to a rigid flexible circuit board manufacturing method in which a plurality of through holes are formed at regular intervals in a prepreg layer in a flexible region of a rigid flexible circuit board in order to increase the flexibility of a rigid flexible circuit board, The present invention relates to a method of manufacturing a rigid flexible circuit board in which interlaminar holes are filled with a molten insulating member to improve interlaminar bondability and flexibility in a flexible region.

Recently, as the production technology has been continuously evolving, electronic devices have not developed in the direction of light weight shortening among the electronic products, and all kinds of micro portable electronic products such as mobile phones and digital cameras have high density interconnection (abbreviated HDI ) It is a product under technical development.

High-density interconnects, that is, interconnecting the layers and layers of a circuit board through the formation of microchannels, are the current state of the art in circuit board fabrication.

And as these high-density interconnect manufacturing processes are combined with build-up technology, circuit boards can be developed in the direction of thinness and miniaturization.

The build-up method is a method of using a concept of sequential lamination on the basis of a double-sided or single-sided circuit board, in which a circuit layer is sequentially added to the outside of the substrate, and the layers are mutually connected by a blind hole.

The blind holes and buried holes that communicate between some layers can eliminate the space occupied by the through holes on the substrate surface and use a limited outer layer area as much as possible for wiring and welding parts, A multilayer printed circuit board having a required number of layers can be obtained.

Currently, printed circuit boards have different strengths depending on the insulating material used and can be classified into rigid printed circuit boards, flexible printed circuit boards (FPC) and rigid flexible printed circuit boards.

A rigid flexible circuit board is a printed circuit board having one or a plurality of rigid regions and one or more flexible regions on one printed circuit board, and combines the advantages of a rigid substrate and a flexible substrate as a combination of a flexible substrate and a rigid substrate .

The flexible printed circuit board can be bent, rolled or folded freely on the basis of the flexible circuit board, so that the product manufactured by the rigid flexible circuit board is not only easy to assemble but also can be folded to form a very good close mounting type, It is possible to omit the installation so as to reduce or not to use the connector and the terminal welding so that the space and the weight can be reduced and the electrical interference can be reduced or prevented to improve the electrical performance and the electronic device It can fully satisfy the demand that develops in the direction of digestion and multifunction.

Especially, it adopts high density interconnect technology and rigid flexible circuit board in order to make it thin, light, and wheel, it is easy to satisfy three dimensional assembly demand, and verified blind hall, precise line width and line length, Technology, etc., and it has been extensively applied to the features of thinning and miniaturization of circuit boards.

At present, the working material of the rigid flexible circuit board includes a rigid substrate material and a flexible substrate material.

Generally, the rigid substrate material and the flexible substrate material are separately processed at the time of processing, and then the substrates are laminated and then the two substrate materials are laminated together using a prepreg.

In the case of such a manufacturing method, all the conductive layers which are the material layers of the flexible area in the rigid flexible printed circuit board are made of the flexible substrate material, and the rigid-flexible circuit board has the rigid area and the waste (dummy) area A flexible printed circuit board (also referred to as a Flexible Copper Clad Laminate (abbreviated as FCCL or a planar copper substrate, a flexible copper film substrate, and a flexible printed circuit board) is used by using a flexible substrate material in an area in which a material is not required to be used. Which is a processing material of the flexible substrate material, and wastes the flexible substrate material. However, since the production cost of the flexible copper film substrate is relatively high, the manufacturing cost of the electronic device (or product) using the printed circuit board actually increases.

According to the prior art, in Japanese Patent No. 10-1319808 (Oct. 10, 2013), there is provided a method of manufacturing a semiconductor device, comprising the steps of: providing a first flexible film having a first metal layer formed on one surface or both surfaces thereof; patterning the first metal layer to form a circuit pattern; Forming a second flexible film having a second metal layer on one surface thereof on one surface or both surfaces of the first flexible film so that a surface on which the second metal layer is not formed faces the first flexible film; Forming a first conductive layer comprising the second metal layer and the plating layer by forming a plating layer on the second metal layer, patterning the first conductive layer in the rigid region R to form a circuit pattern, Providing an antioxidant protective layer on the first conductive layer in the region F and forming a circuit layer composed of an insulating layer and a second conductive layer formed on the insulating layer on the second flexible film It provided the above lamination step, and the flexible regions (F) substrate manufacturing method contest flexible printed circuit for removing a layer of the circuitry that.

However, when a rigid flexible circuit board is manufactured as in the prior art, if a prepreg containing a glass fiber layer is used in a bent portion which is a flexible region, the flexibility of the circuit board is lowered. If such a circuit board is bent as needed There was a problem that the glass fiber layer of the prepreg was damaged, resulting in product failure.

The present invention relates to a rigid flexible circuit board in which a plurality of through holes are formed in a prepreg layer of a flexible region at regular intervals and the inner layer insulating layer melted by heat generated by hot pressing is filled in the through holes, And an object of the present invention is to provide a method of manufacturing a rigid flexible circuit board in which the interlayer bonding property and the bendability are improved.

A step of preparing a core layer having a base layer and an inner layer circuit formed on a surface thereof, b) a prepreg layer having a plurality of through holes formed at regular intervals corresponding to the flexible region of the core layer, C) stacking a prepared prepreg layer on the core layer stacked on top of the base layer of the core layer while laminating a core layer on top and bottom of the base layer with the base layer as a center, D) subjecting the inner layer circuit board to hot pressing while laminating an outer layer insulating layer bonded to the surface of the inner layer circuit board with a copper foil on the upper and lower surfaces thereof, and e) Forming an outer layer circuit on the surface of the outer layer insulating layer by etching; and f) positioning the outer layer circuit on the flexible layer in either the upward or downward direction with respect to the prepreg layer Removal of the pile board, and a step of completing the rigid flexible circuit board.

At this time, in the step of laminating the core layer on the upper and lower sides of the base layer and the prepreg layer on the core layer laminated on the base layer while centering the base layer as step c) according to the present invention, When the core layers are respectively located on the upper and lower sides of the base layer, an inner layer insulating layer is disposed between the base layer and the core layer.

In the step of laminating the core layer laminated on the upper and lower sides of the base layer and the prepreg layer on the core layer laminated on the base layer with the base layer being the center of step c) according to the present invention, When the prepared prepreg layer is laminated while laminating the core layer on the base layer, the release paper is pre-laminated on the flexible region of the core layer located above the base layer of the core layer, And laminated on the core layer.

Further, in the step of hot-pressing while the outer-layer insulating layer having the copper foil bonded on the surface of step d) according to the present invention is laminated on the upper and lower surfaces of the inner-layer circuit board, the hot- The inner layer insulating layer is melted and the melted inner layer insulating layer fills the through holes of the prepreg.

In addition, in the step of completing the rigid flexible circuit board by removing the substrate dummy located in the flexible region in either the upper or lower direction with respect to the prepreg layer in the flexible region of step f) according to the present invention, A boundary dividing the flexible region and the rigid region is drilled on one side of the circuit board by a drill, and then the substrate pile in the flexible region is removed while punching the drilled boundary, thereby completing the rigid flexible circuit board.

A method of manufacturing a rigid flexible circuit board according to an embodiment of the present invention includes the steps of forming a plurality of through holes in a prepreg layer of a flexible region of a rigid flexible circuit board at regular intervals, And the inner layer insulating layer melted by the adhesive is filled and filled, thereby improving interlaminar bondability and flexibility of the flexible region.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view illustrating a manufacturing process of a rigid flexible circuit board according to an embodiment of the present invention; FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention, and not all of the technical ideas of the present invention are described. Therefore, at the time of the present application, It should be understood that variations can be made.

The present invention relates to a rigid flexible circuit board in which a plurality of through holes are formed at predetermined intervals in a prepreg layer of a flexible region of a rigid flexible circuit board in order to enhance the flexibility of the rigid flexible circuit board and an insulating member is filled in the through holes, And a method of manufacturing a rigid flexible circuit board with improved flexural characteristics, which will be described in detail with reference to the drawings.

1, a method of manufacturing a rigid flexible circuit board according to an embodiment of the present invention includes: preparing a base layer 10 and a plurality of core layers 20 in a step a).

At this time, the base layer 10 is made of polyimide having excellent heat resistance, little change in characteristics according to temperature difference, good impact resistance, good dimensional stability, and excellent electrical characteristics (insulation) The core layer 20 is formed with an inner layer circuit 22 on both upper and lower surfaces of the insulating substrate layer 21 based on the insulating substrate layer 21 which is an insulating material.

The inner layer circuit 22 of the core layer 20 may be formed by performing photolithography, E-beam lithography, ion plating, or the like on the copper foil formed on both the upper and lower surfaces of the insulating substrate layer 21. [ It is preferable to implement the inner layer circuit 22 by etching in any one of the following methods: Focused Ion Bean lithography, Dry etching, Wet etching, and Nano-imprint Do.

When the core layer 20 is joined to the base layer 10 to form an inner layer circuit board, the core layer 20 is positioned on the upper and lower portions of the base layer 10 with the base layer 10 as a center A through hole 23 is formed in the core layer 20 located on the base layer 10 along the boundary between the rigid region and the flexible region.

Next, in step b), a prepreg layer 30 is prepared.

The prepreg layer 30 is formed by preliminarily impregnating a reinforcing fiber with a matrix resin. The prepreg layer 30 is formed at a predetermined interval in the flexible region of the prepreg layer 30 at a position corresponding to the flexible region of the core layer 20 A plurality of through holes 31 are formed.

It is preferable that the through-hole 31 has a length in a direction perpendicular to the bending direction of the circuit board. A plurality of through-holes 31 are formed at regular intervals along the flexible region of the prepreg layer 30, The bending property of the prepreg layer 30 is improved while the stress generated when the substrate is bent is dispersed so as not to be concentrated in any one of the flexible regions.

Next, in step c), core layers 20 are laminated on the upper and lower surfaces of the base layer 10 with the base layer 10 as a center, and the base layer 10 of the core layer 20, The prepared prepreg layer 30 is laminated on the core layer 20 laminated on the upper surface of the core layer 20 to form an inner layer circuit board.

An inner layer insulating layer 40 is disposed between the base layer 10 and the core layer 20 when the core layer 20 is positioned on the upper and lower portions of the base layer 10, The inner layer insulating layer 40 is preferably made of a thermoplastic material that can be melted by a hot pressing process to be performed later and the melted inner layer insulating layer 40 is formed between the base layer 10 and the core layer 20 The circuit formed on the surface of the core layer 20 is insulated and the interlayer adhesive functions so that the base layer 10 and the core layer 20 are laminated to each other.

In the step c), when the prepared prepreg layer 30 is laminated on the upper surface of the base layer 10, the prepreg layer 30 is laminated on the flexible region of the core layer 20, And the prepreg layer 30 is laminated on the core layer 20 to form an inner layer circuit board.

Here, the release paper 41 is not bonded to the flexible area of the prepreg layer 30, so that the substrate dummy to be removed by the subsequent punching process is easily separated from the substrate.

Next, in step d), hot press is performed while stacking the outer layer insulating layer 50 on which the copper foil 51 is bonded on the upper and lower surfaces of the inner layer circuit board.

In the hot pressing process performed in step d), the circuit board is positioned between the pair of heat plates, and heat and pressure of high temperature are applied to the circuit board to bond the interlayer members constituting the circuit board to each other. When a high temperature is applied to the inner layer circuit board in the hot press process, the inner layer insulation layer 40 disposed between the layers is melted and melted to form the base layer 10 constituting the inner layer circuit board by the melted inner layer insulation layer 40. [ The core layer 20, the prepreg layer 30, and the outer layer insulating layer 50 are bonded to each other.

When the inner layer insulating layers 40 disposed between the base layer 10, the core layer 20, the prepreg layer 30, and the outer layer insulating layer 50 are melted, the inner layer insulating layer 40 has fluidity A through hole 23 formed along the boundary between the rigid region and the flexible region of the core layer 20 stacked on the upper surface of the base layer 10 and a through hole 23 formed in the flexible region of the prepreg layer 30 The molten inner layer insulating layer 40 flows into the formed plurality of through holes 31 to fill the through holes 23 and the through holes 31 to improve the interlayer bonding property.

Next, in step e), the outer layer circuit 52 is formed by etching the copper foil 51 of the outer layer insulating layer 50.

The copper foil 51 may be formed by a photolithography process, an E-beam lithography process, a focused ion beam lithography process, a dry etching process, a wet etching process, Nano-imprint, and may be implemented as the outer layer circuit 52. [0053] FIG.

On the outer layer circuit 52 formed by the above process, the outer layer circuit insulation layer 60 is formed to insulate the outer layer circuit 52.

Here, the outer layer circuit insulation layer 60 may be formed by applying PSR (Photo Imageable Solder Resist) ink to the surface of the outer layer circuit 52 and curing the insulation layer.

In the embodiment of the present invention, the outer layer insulating layer 50 is laminated once. However, the outer layer insulating layer 50 is laminated successively and repeatedly in a circuit design, Layer circuit constituting the second and third outer layer circuits in this order.

Next, in step f), the substrate dummy 71 located in the flexible region in either the upward or downward direction with respect to the prepreg layer 30 is removed from the circuit board to remove the rigid flexible circuit board It completes.

At this time, the substrate dummy 71 is located in the flexible region of the circuit board, and it is preferable to remove the substrate dummy 71 in the direction in which the release sheets 41 are laminated with respect to the prepreg layer 30. [

The process of removing the substrate dummy 71 according to an embodiment of the present invention will be described with reference to the drawings. A boundary between the flexible region and the rigid region of the circuit board is drilled by a drill.

At this time, the drilling depth is preferably drilled to a point near the through hole 23 formed in the rigid region of the core layer 20 bonded to the upper portion of the base 10 of the inner layer circuit board and the flexible region boundary.

Then, the substrate dummy 71 in the flexible region is removed while punching the drilled rigid region and the flexible region boundary with a punch.

At this time, the depth of the pad is punched to the release paper 41 located on one side of the flexible region of the prepreg layer 30. When the release paper 41 is punched out, the release paper 41 is pressed against the substrate pile 71, Are easily separated from the circuit board.

Therefore, when the substrate dummy 71 is removed from the circuit board by the above process, the rigid flexible circuit board is completed.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: base layer
20: core layer
21: Insulation substrate layer
22: Inner layer circuit
23: Through hole
30: prepreg layer
31: penetration hole
40: Inner layer insulating layer
41: release paper
50: outer layer insulating layer
51: Copper foil
52: outer layer circuit
60: outer layer circuit insulating layer
71: substrate stack

Claims (5)

a) preparing a plurality of core layers each having a base layer and an inner layer circuit formed on a surface thereof;
b) preparing a prepreg layer having a plurality of through holes at regular intervals corresponding to the flexible region of the core layer;
c) laminating prepreg layers on the core layer stacked on top of the base layer of the core layer while laminating the core layers on top and bottom of the base layer with the base layer as a center, thereby forming an inner layer circuit board ;
d) performing a hot press while laminating an outer layer insulating layer bonded to the surface of the inner foil on the upper and lower surfaces of the inner layer circuit board;
e) etching the copper foil of the outer layer insulating layer to form an outer layer circuit on the surface of the outer layer insulating layer; And
f) completing the rigid flexible circuit board by removing a substrate dummy located in a flexible region in either the upward or downward direction of the prepreg layer from the circuit board, Gt;
The method according to claim 1,
layer prepreg layer is laminated on the core layer laminated on the base layer of the core layer while laminating the core layers on the upper and lower sides of the base layer with the base layer being the center step c) In the step of forming
Wherein an inner layer insulating layer is disposed between the base layer and the core layer when the core layer is positioned on each of the upper and lower portions of the base layer.
The method of claim 2,
layer prepreg layer is laminated on the core layer laminated on the base layer of the core layer while laminating the core layers on the upper and lower sides of the base layer with the base layer being the center step c) In the step of forming
When a prepared prepreg layer is laminated on top of the base layer, a release paper is pre-laminated on the flexible region of the core layer located above the base layer of the core layer, Is laminated on the core layer. ≪ RTI ID = 0.0 > 11. < / RTI >
The method of claim 2,
In the step of performing the hot press while laminating the upper and lower surfaces of the inner layer circuit board, which is the step d), with the outer layer insulating layer joined to the surface of the copper foil
Wherein the inner layer insulating layer is melted by the heat applied to the inner layer circuit board by the hot press so that the melted inner layer insulating layer fills the through holes of the prepreg.
The method according to claim 1,
removing the substrate dummy located in the flexible region in either the upward or downward direction with respect to the prepreg layer as the step of f), and completing the rigid flexible circuit board
A rigid flexible circuit board is completed by drilling a boundary separating the flexible region and the rigid region on one side of the circuit board and then drilling the drilled boundary with a punch to remove the substrate dummy in the flexible region Wherein the rigid flexible circuit board is manufactured by a method of manufacturing a rigid flexible circuit board.

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