KR101771801B1

KR101771801B1 - Printed circuit board and manufacturing method of the same

Info

Publication number: KR101771801B1
Application number: KR1020150127220A
Authority: KR
Inventors: 김한; 하상렬; 김성한; 이경호; 안석환; 강명삼
Original assignee: 삼성전기주식회사
Priority date: 2015-06-29
Filing date: 2015-09-08
Publication date: 2017-08-25
Also published as: KR20170002259A

Abstract

The present invention proposes a novel structure of a printed circuit board having a fine pattern and high rigidity to provide a flexible printed circuit board having excellent bending characteristics. In particular, the printed circuit board according to one aspect of the present invention includes at least one And an outer layer including a reinforcing layer and a wiring portion which are respectively disposed on first and second main surfaces facing each other of the inner layer and the inner layer and which have a higher rigidity than the insulating layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a printed circuit board

The present invention relates to a printed circuit board and a manufacturing method thereof.

Recently, there is a need to improve the heat dissipation characteristics and stability of the printed circuit board. Particularly, there is a need for an electronic device package such as an MCP (Multi Chip Package) in which a plurality of semiconductor chips are stacked on one substrate or a POP (Package On Package) in which a plurality of substrates on which semiconductor chips are mounted are stacked, , A printed circuit board for an electronic device package is required to have improved heat dissipation characteristics, stability, and reliability.

In the case of a printed circuit board, a plurality of layers having different physical properties can be obtained. In this case, warpage may occur due to the difference in physical properties. Further, even when an electronic element or the like is embedded in the printed circuit board, warping due to a difference in physical properties between the element and the substrate material may occur. Nowadays, the physical properties (eg elastic modulus) of the materials used in the printed circuit board are controlled to cope with the warpage, but as the thinning of the printed circuit board is accelerated, the problem of warpage that can occur unpredictably during the manufacturing process becomes more serious It is expected.

In addition, as the demand for miniaturization of various electronic products using printed circuit boards increases, attempts have been made to miniaturize wiring patterns included in printed circuit boards.

One of the objects of the present invention is to provide a high-density printed circuit board having a micro-wiring structure with high flexural characteristics and high rigidity, and a method for efficiently manufacturing the same.

As a method for solving the above-mentioned problems, the present invention is to propose a novel structure of a printed circuit board having a fine pattern and high rigidity to have excellent bending characteristics through one embodiment. Specifically, The printed circuit board according to one aspect includes an inner layer including at least one insulating layer and a wiring portion and a reinforcing layer and a wiring portion which are respectively disposed on first and second main surfaces facing each other of the inner layer, Outer layer.

In this case, representative examples of the material constituting the insulating layer and the reinforcing layer of the inner layer are photosensitive resin and invar alloy, respectively, but may be replaced with other materials which can have a similar effect if necessary.

According to another aspect of the present invention, there is also provided a method for efficiently manufacturing the above-described structure. Specifically, the inner layer and the reinforcing layer may be laminated together and then pressed to obtain a substrate structure.

As one of the effects of the present invention, it is possible to improve the bending performance by disposing the outer layer having a relatively excellent flexural rigidity at the outer periphery of the inner layer, and furthermore, by embodying the fine pattern in the inner layer, a high density printed circuit board can be obtained . In addition, as another effect of the present invention, it is possible to provide a manufacturing method capable of efficiently manufacturing a printed circuit board having the above-described structure.

The various and advantageous advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the course of describing a specific embodiment of the present invention.

1 is a cross-sectional view schematically showing a printed circuit board according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view schematically showing the shape of an outer layer which can be adopted in the modified example of the embodiment of Fig.
3 to 5 are cross-sectional views schematically showing a printed circuit board according to another embodiment of the present invention.
6 to 10 are process drawings schematically showing a method of manufacturing a printed circuit board according to a temporary form of the present invention.
11 is a graph showing the flexural characteristics of a printed circuit board obtained according to an embodiment of the present invention as a comparative example.

Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided for a more complete description of the present invention to the ordinary artisan. Accordingly, the shapes and sizes of the elements in the drawings may be exaggerated for clarity of description, and the elements denoted by the same reference numerals in the drawings are the same elements.

It is to be understood that, although 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 embodiments, but, on the contrary, Will be described using the symbols. Further, throughout the specification, when an element is referred to as "including" an element, it means that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

1 is a cross-sectional view schematically showing a printed circuit board according to an embodiment of the present invention. Referring to FIG. 1, a printed circuit board 100 according to an embodiment of the present invention may include an inner layer 110 and an outer layer 120 disposed around the inner layer 110 and provided for bending relief. Hereinafter, the components of the printed circuit board 100 will be described in detail.

The inner layer 110 includes an insulating layer 111 and wiring portions 112 and 113. In this case, a plurality of insulating layers 111 may be stacked as shown in FIG. However, according to the embodiment, only one insulating layer 111 may constitute the inner layer 110. When a plurality of insulating layers 111 are provided, a plurality of insulating layers 111 may be formed by stacking materials including materials having different stiffnesses, as in the embodiment described later.

The insulating layer 111 included in the inner layer 110 may be any material having electrical insulation properties. For example, a thermosetting resin such as a photosensitive resin or an epoxy resin, a thermoplastic resin such as polyimide, A resin impregnated with a reinforcing material such as an inorganic filler, for example, a prepreg (PPG) may be used. In particular, in this embodiment, an insulating layer 111 including a photosensitive material (Photo Imageable Dielectric, PID) is used. In the case of using a photosensitive material, it is easier to form a fine pattern on the insulating layer 111 than in the case of using mechanical processing or the like, which is advantageous for manufacturing a high-density printed circuit board. However, since the insulating layer 111 using a photosensitive material has a relatively small amount of filler such as SiO ₂ and is generally vulnerable to bending, the outer layer 120 having a reinforcing function is disposed on the outer periphery of the inner layer 110, Respectively.

The wiring portion included in the inner layer 110 includes the wiring pattern 112 and the conductive vias 113 and may be formed of a metal material such as copper, nickel, silver, or the like having high electrical conductivity. As described above, when the inner layer 110 is formed of a material containing a photosensitive resin, the wiring patterns 112 and 113 included in the inner layer can be easily formed into a fine pattern, That is, the wiring pattern 123 and the conductive via 124, can be made smaller.

The inventors of the present invention have found that when the layer having a relatively high rigidity is disposed on the outer periphery of the substrate rather than the center thereof, it is advantageous in improving the flexural rigidity. Based on this, the outer layer 120 is formed on the outer periphery of the inner layer 111 The printed circuit board 100 of FIG. Specifically, the outer layer 120 is disposed on the first and second main surfaces facing each other of the inner layer 110, and includes the reinforcing layer 121 and the wiring portions 123 and 124.

The reinforcing layer 121 included in the outer layer 120 is more rigid than the insulating layer 111 of the inner layer 110 and may be disposed at the outermost portion of the printed circuit board 100 as shown in FIG. Here, it is understood that the outermost portion of the printed circuit board 100 is disposed in an area in contact with the solder resist 130. In this case, the outer layer 120 disposed on the outer periphery may include a wiring portion like the inner layer 121, and the conductive vias 124 in the wiring portion penetrate the reinforcing layer 121. The printed circuit board 100 may include a solder resist 130 covering the outer layer 120 and formed to expose at least a part of the wiring portion of the outer layer 120.

For example, the reinforcing layer 121 includes a material having a stiffness higher than that of the photosensitive material. In the present embodiment, the reinforcing layer 121 is made of a material containing an Invar alloy, i.e., an Fe-Ni alloy. ). Invar alloy is an alloy of steel and nickel. It is a highly rigid material with a modulus of about 140 GPa although it varies depending on the Ni content. Therefore, the elastic modulus of the substrate is increased and the bending stiffness ) Can also provide an enhanced effect. In this case, as described above, the reinforcing layer 121 is arranged symmetrically on the outer layer apart from the center rather than the center of the substrate 100, thereby maximizing the improvement in flexural rigidity. However, other materials such as a prepreg may be used as the reinforcing layer 121 in addition to the invar alloy as long as it can perform the above-described bending property improving function.

1, the outer layer 120 may include an insulating portion 122 disposed at the upper and lower portions of at least the reinforcing layer 120 to insulate the reinforcing layer 121 from the wiring portions 123 and 124, The insulating portion 122 may be used when the reinforcing layer 121 is made of a conductive material such as an invar alloy. In this case, if necessary, the reinforcing layer 121 may be electrically connected to the wiring patterns 112 and 123 disposed on the upper portion or the lower portion of the reinforcing layer 121. For this purpose, conductive vias passing through the insulating portion 112 may be provided .

The insulating portion 122 may be employed to improve the bending property even when the reinforcing layer 121 is not a conductive material. The insulating portion 122 constituting the outer layer 120 may include a material having a higher rigidity than the insulating layer 111 of the inner layer 110 in view of further improving the flexural rigidity. Specifically, when the insulating layer 111 of the inner layer 110 is formed of a photosensitive material, the insulating portion 122 of the outer layer 120 may be formed of a prepreg, epoxy, or the like.

2, the adhesive layer 114 may be interposed between the reinforcing layer 121 and the insulating portion 122 in order to improve the bonding force between the interfaces. The adhesive layer 114 may be made of a material such as copper having a high adhesive strength and good electrical conductivity and heat radiation performance. When the adhesive layer 114 is made of a conductive material such as copper or the like, it can be electrically connected to the wiring patterns 112 and 123 disposed on the upper portion or the lower portion of the adhesive layer 114. For this purpose, conductive vias passing through the insulating portion 112 are provided . The modified embodiment of FIG. 2 may be applied to other embodiments described below.

3 to 5 are cross-sectional views schematically showing a printed circuit board according to another embodiment of the present invention. The embodiment shown in Figs. 3 to 5 gives a change to the material constituting the inner layer in the embodiment of Fig.

The printed circuit board 200 according to the embodiment of FIG. 3 includes an inner layer 210 and an outer layer 220 provided around the inner layer 210 for improving flexural rigidity. In this embodiment, the inner layer 210 includes a plurality of insulating layers 211 and 214 and wiring portions 212 and 213, and the plurality of insulating layers 211 and 214 include materials having different rigidities from each other Can be formed in a stacked structure. In particular, the plurality of insulating layers may be of a stiffer form than the one 211 disposed centrally in the enclosure. For example, the center 214 of the plurality of insulating layers may include a prepreg to further improve the flexural rigidity of the substrate, and may be provided in the form of CCL (Copper Clad Laminate) during the substrate manufacturing process . In addition, one of the plurality of insulating layers 211 disposed at the periphery may include a photosensitive material to provide a structure suitable for a fine pattern embodying.

The outer layer 220 includes the reinforcing layer 221 and the wiring portions 223 and 224 made of Invar alloy or the like disposed on the first and second main surfaces facing each other of the inner layer 210 as in the previous embodiment . Also, a solder resist 230 may be formed to cover the outer layer 220.

Next, the printed circuit board 300 according to the embodiment of FIG. 4 includes an inner layer 310 and an outer layer 320 provided around the inner layer 310 for improving bending stiffness. In this embodiment, the inner layer 310 includes a plurality of insulating layers 311 and 314 and wiring portions 312 and 313. The plurality of insulating layers 311 and 314 include materials having different stiffnesses from each other Can be formed in a stacked structure. In particular, the plurality of insulating layers may be of a shape having a higher rigidity than the one 311 disposed at the center of the insulating layer 311. For example, a center 314 of the plurality of insulating layers constitutes three layers, and the bending rigidity of the substrate can be further improved by including the prepreg. In this case, the three central layers 314 having excellent flexural rigidity can be obtained in the form of stacking the prepreg in both directions in the CCL during the substrate manufacturing process. As in the previous embodiment, the outline 311 of the plurality of insulating layers may include a photosensitive material to provide a structure suitable for fine pattern implementation.

The outer layer 320 includes a reinforcing layer 321 and wiring portions 323 and 324 made of an invar alloy or the like and disposed on the first and second main surfaces facing each other of the inner layer 310 as in the previous embodiment . In addition, a solder resist 330 may be formed to cover the outer layer 320.

Next, the printed circuit board 400 according to the embodiment of FIG. 5 includes an inner layer 410 and an outer layer 420 provided therearound for improving flexural rigidity. In this embodiment, the inner layer 410 includes a plurality of insulating layers 414 and wiring portions 412 and 413, and the plurality of insulating layers 414 include a high-rigidity material such as a prepreg, The flexural rigidity can be further improved. In this case, the plurality of insulating layers 414 can be obtained by stacking the prepreg in the CCL in both directions during the substrate manufacturing process. Unlike the previous embodiment, the inner layer 410 is formed using only a high-rigidity material such as a prepreg instead of using a photosensitive material, and the inner layer 410 may be used when a higher rigidity is required than a fine pattern.

The outer layer 420 includes the reinforcing layer 421 and the wiring portions 423 and 424 made of Invar alloy or the like and disposed on the first and second main surfaces facing each other of the inner layer 410 as in the previous embodiment . In addition, a solder resist 430 may be formed to cover the outer layer 420.

Hereinafter, a method of efficiently manufacturing the above-described printed circuit board will be described, and the above-described components can be understood in more detail through the description of the following manufacturing method. 6 to 10 are process drawings schematically showing a method of manufacturing a printed circuit board according to a temporary form of the present invention.

First, the method of manufacturing a printed circuit board according to the present embodiment basically includes the steps of: providing an inner layer including an insulating layer having a wiring portion; and forming an outer layer including a reinforcing layer and a wiring portion, Respectively, on the first and second main surfaces facing each other.

An example of the above-described manufacturing process will be described in detail. First, as shown in Fig. 6, a wiring pattern 112 is formed on the carrier 140. Next, as shown in Fig. The carrier 140 is provided for handling a single insulating layer and may include a base 141, a release agent 142, and a seed layer 143. In this case, the configuration of the carrier 140 may be appropriately modified as required, and for example, the release agent 142 and the seed layer 143 may be omitted. The wiring pattern 112 can be obtained by plating a material such as copper using the seed layer 143 as a seed.

Next, as shown in FIG. 7, an insulating layer 111 is formed to join with the carrier 140, and a conductive via 113 in the wiring portion is formed. In this embodiment, the insulating layer 111 is formed on the upper and lower sides of the carrier 140 to improve the process efficiency. The insulating layer 111 may include a photosensitive material as described above and may be formed on the carrier 140 by a process such as vapor deposition or the like beforehand. When the insulating layer 111 includes a photosensitive material, wiring portions such as the conductive vias 113 can be formed in a fine pattern without using mechanical processing.

8, after the insulating layer 111 is formed, the carrier 140 is separated or removed from the insulating layer 111 and the wiring parts 112 and 113 (not shown) are removed from one carrier 140 as described above, ) Can be obtained. In this case, if necessary, the remaining seed layer 142 may be removed by an appropriate etching process.

9, an outer layer 120 is produced, and the outer layer 120 includes a reinforcing layer 121 and wiring portions 123 and 124, as in the previous embodiment, Structure. The present embodiment will be described on the basis of a form in which the reinforcing layer 121 is formed of an invar alloy and the insulating portion 122 is formed so as to separate it from the wiring portions 123 and 124. The insulating portion 122 has an improved flexural rigidity A prepreg can be used from the side. In this case, in addition to the prepreg, the insulating portion 122 may be formed of a material such as epoxy resin. As an example of forming the outer layer 120, the reinforcing layer 121 and the insulating portion 122 may be provided independently and then stacked. Then, the wiring portions 123 and 124 may be formed .

10, after the insulating layer 111 and the outer layer 120 are formed, the inner layer 110 including the insulating layer and the outer layer 120 are laminated, and then the outer layer 120 is laminated in the laminated direction , A lamination structure of the substrate can be obtained by applying pressure from the upper and lower portions with reference to Fig. In this case, the insulating layer included in the inner layer 110 may be provided in an appropriate number as required, and the inner layer 110 and the outer layer 120 may be laminated together. Thereafter, the solder resist 130 is formed at the outermost portion of the printed circuit board to obtain the printed circuit board described in the foregoing embodiment. The solder resist 130 is suitable for use as an IC package substrate or the like. It may be provided in an appropriate shape depending on the function.

Meanwhile, the inventors of the present invention conducted simulation in order to investigate the bending characteristics of the reinforcing structure by the outer layer proposed in the present invention. 11 is a graph showing the flexural characteristics of a printed circuit board obtained according to an embodiment of the present invention as a comparative example. The materials constituting the comparative example and the embodiment are as follows, and the thicknesses of the inner layer and the outer layer are realized at similar levels.

Comparative Example: A substrate having a whole prepreg formed without separating the inner layer and the outer layer

Example 1: An inner layer was formed of a photosensitive material (including 40 wt% of SiO ₂ ) and an outer layer of a substrate formed of prepreg (40 um)

Example 2 The inner layer was formed of a photosensitive material (including 40 wt% of SiO ₂ ), and the outer layer of the inner layer was formed of a substrate in which an invar alloy (10 um) was inserted between prepregs (corresponding to insulation portions in the above-

Example 3 The inner layer was formed of a photosensitive material (including 40 wt% of SiO ₂ ), and the outer layer of the inner layer was formed of an insulator alloy (20 um) inserted between prepregs

As can be seen from the simulation results of FIG. 11, the structure using the photosensitive material in the inner layer is accompanied by a decrease in the flexural rigidity, but it can be supplemented when the reinforcing layer is disposed outside. Particularly, when the invar alloy is used as a reinforcing layer in an appropriate thickness and used together with the prepreg, a superior level of flexural rigidity can be obtained in the case of using only the prepreg (Comparative Example).

The present invention is not limited to the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

100, 200, 300, 400: printed circuit board
110, 210, 310, 410: inner layer
111, 211, 214, 311, 314, 414: insulating layer
112, 212, 313, 412, 123, 223, 323, 423:
113, 213, 313, 413, 124, 224, 324, 424: conductive vias
114: adhesive layer
120, 220, 320, 420: outer layer
121, 221, 321, 421: reinforced layer
122, 222, 322, 422:
130, 230, 330, 430: solder resist
140: Carrier
141: Base
142: Releasing agent
143: Seed layer

Claims

An inner layer comprising at least one insulating layer and a wiring portion; And
And an outer layer including a reinforcing layer and a wiring portion which are respectively disposed on first and second major surfaces of the inner layer facing each other and which are more rigid than the insulating layer,
Wherein the outer layer further includes an insulating portion disposed at upper and lower portions of at least the reinforcing layer to insulate the reinforcing layer from wiring portions included in the outer layer, wherein the insulating portion of the outer layer includes a material having higher rigidity than the insulating layer of the inner layer,
And a side surface of the reinforcing layer is exposed to the outside.

The method according to claim 1,
Wherein the insulating layer comprises a photosensitive material.

The method according to claim 1,
Wherein a wiring portion included in the inner layer has a smaller wiring pitch than a wiring portion included in the outer layer.

The method according to claim 1,
Wherein the reinforcing layer comprises an Fe-Ni alloy.

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The method according to claim 1,
Wherein the insulation of the outer layer comprises a prepreg and the insulation layer of the inner layer comprises a photosensitive material.

The method according to claim 1,
Wherein the wiring portion of the outer layer includes a conductive via penetrating through the reinforcing layer.

The method according to claim 1,
Wherein a plurality of insulation layers of the inner layer are provided, and the insulation layer of the inner layer includes materials having different rigidities.

10. The method of claim 9,
Wherein the plurality of insulating layers are more rigid than those disposed at the outer peripheries.

11. The method of claim 10,
Wherein a center of the plurality of insulating layers comprises a prepreg, and wherein disposed on the outer side comprises a photosensitive material.

Providing an inner layer comprising an insulating layer having a wiring portion; And
Disposing an outer layer including a reinforcing layer and a wiring portion having a stiffness higher than that of the insulating layer on the first and second major faces of the inner layer facing each other,
Wherein the outer layer includes an insulating portion disposed at upper and lower portions of at least the reinforcing layer to insulate the reinforcing layer from wiring portions included in the outer layer, wherein the insulating portion of the outer layer includes a material having higher rigidity than the insulating layer of the inner layer, Is exposed to the outside.

13. The method of claim 12,
Further comprising the step of laminating the insulating layer and the outer layer, and then applying pressure from a direction in which the outer layer is laminated.

14. The method of claim 13,
Wherein the insulating layer and the outer layer are laminated together.

13. The method of claim 12,
Wherein the reinforcing layer comprises an Fe-Ni alloy.

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