KR102313803B1 - Flexible circuit clad laminate, printed circuit board using it, and method of manufacturing the same - Google Patents

Abstract

A flexible circuit copper-clad laminate according to an embodiment of the present invention includes a resin layer; an adhesion strengthening layer containing silane as formed on at least one surface of the resin layer by a pretreatment operation; a tie coat layer formed on the silane-containing adhesion strengthening layer; and a copper layer formed on the tie coat layer.

Description

Flexible circuit clad laminate, printed circuit board using it, and method of manufacturing the same

The present invention relates to a flexible circuit copper clad laminate, a printed circuit board using the same, and a method for manufacturing the same, and more particularly, to improve adhesion between a substrate and a metal, an adhesion strengthening layer formed by wet pretreatment on a resin layer It relates to a flexible circuit copper-clad laminate, a printed circuit board using the same, and a method for manufacturing the same.

A printed circuit board (PCB) is an electrical wiring to connect various parts expressed in a wiring diagram according to a circuit design, and plays a role of connecting or supporting various parts. In particular, the demand for printed circuit boards has increased with the development of electronic devices such as notebook computers, mobile phones, PDAs, small video cameras, and electronic notebooks. Furthermore, the electronic devices are increasingly smaller and lighter as portability is emphasized. Accordingly, printed circuit boards are becoming more integrated, smaller, and lighter.

According to the physical properties of the printed circuit board, a rigid printed circuit board, a flexible printed circuit board, a rigid-flexible printed circuit board in which the two are combined, and a rigid-flexible printed circuit board similar to a multi-flexible divided into printed circuit boards. In particular, flexible circuit clad laminate (FCCL), a raw material for flexible printed circuit boards, is used in digital home appliances such as mobile phones, digital camcorders, laptops, and LCD monitors. Demand is growing rapidly.

The flexible circuit copper-clad laminate is a laminate of a polymer film layer and a metal conductive layer, and is characterized by flexibility. The flexible circuit copper-clad stacking plate is used for electronic devices or material parts of electronic devices that require flexibility or flexibility, and contributes to miniaturization and weight reduction of electronic devices.

Conventional flexible circuit copper-clad laminates related to this technology are largely divided into a method of applying a polyimide-based resin to a copper foil and a method of depositing copper on a polymer film. In particular, the copper deposition method can form a very thin copper film.

The deposition-type flexible circuit copper-clad laminate is manufactured by forming a tiecoat layer on a polymer film by sputtering, and then passing it through a copper electrolytic plating bath to electrolytically plated copper.

The fabricated flexible circuit copper-clad laminate is used after the circuit is formed, and semiconductor chips or electric elements are mounted on the circuit, and the miniaturization, multi-pin, and narrow pitch of driver ICs are rapidly progressing. . Accordingly, there is a need for a flexible circuit copper-clad laminate having excellent physical properties such as etching properties, peel strength, and thin film density characteristics.

Among these physical properties, a method of performing dry pretreatment such as plasma pretreatment on the surface of the resin layer has been used to improve the peel strength, particularly, the peel strength between the resin layer and the tie coat layer made of the polymer film. However, there is a problem in that it is difficult to obtain satisfactory peel strength (especially, peel strength at high temperature).

Therefore, there is a need for technology development that can significantly improve the high-temperature peel strength between the resin layer and the tie coat layer by applying a pretreatment other than the conventional pretreatment method.

The present invention has been devised in consideration of the above-described problems, and an object of the present invention is to provide a technique capable of remarkably improving the high-temperature peel strength between the resin layer and the tie coat layer.

However, the technical problems to be achieved by the present invention are not limited to the above-described problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the description of the invention described below.

The present inventors repeated research to develop a technology capable of remarkably improving the high-temperature peel strength between the resin layer and the tie coat layer, and as a result, silane was contained on the resin layer by wet pretreatment using silane. A flexible circuit copper-clad laminate having significantly improved high-temperature peel strength (peel strength between the resin layer and the tie coat layer) has been produced by forming an adhesive strength reinforcing layer.

In addition, the present inventors through continued research, in forming the adhesion strengthening layer containing such a silane, by controlling the thickness of the adhesion strengthening layer containing the silane and the concentration of silane within a certain range to have improved high-temperature peel strength A flexible circuit copper clad laminate has been produced.

A flexible circuit copper-clad laminate according to an embodiment of the present invention developed according to such research includes a resin layer; an adhesion strengthening layer containing silane as formed on at least one surface of the resin layer by a pretreatment operation; a tie coat layer formed on the silane-containing adhesion strengthening layer; and a copper layer formed on the tie coat layer.

The silane may have a composition containing not more than 25% Si, not less than 40% C, not more than 3% O, and not more than 5% N (% means Atomic%).

As a solvent for the silane, isopropyl alcohol may be used.

The thickness of the adhesion strengthening layer may be 3 nm to 30 nm, and the concentration of silane contained in the material used for preparing the adhesion strengthening layer may be 1.0 mol% to 1.2 mol%.

The resin layer may be made of a polyimide resin.

The tie coat layer may be formed to a thickness ranging from 7 nm to 50 nm.

The copper layer may include a copper seed layer formed on the tie coat layer; and a copper film layer formed on the copper seed layer.

Meanwhile, a printed circuit board according to an embodiment of the present invention includes a wiring pattern formed on a copper layer of the flexible circuit copper-clad laminate according to an embodiment of the present invention.

In addition, the method for manufacturing a flexible circuit copper-clad laminate according to an embodiment of the present invention comprises the steps of: (S1) forming a resin layer; (S2) forming an adhesion strengthening layer containing silane by performing a wet pretreatment on at least one surface of the resin layer; (S3) forming a tie coat layer on the adhesion strengthening layer; and (S4) forming a copper layer on the tie coat layer.

The silane may have a composition containing not more than 25% Si, not less than 40% C, not more than 3% O, and not more than 5% N (% means Atomic%).

As a solvent for the silane, isopropyl alcohol may be used.

The step (S2) is a step of controlling the thickness and concentration so that the thickness of the adhesion strengthening layer is 3 nm to 30 nm, and the concentration of silane contained in the material used for the preparation of the adhesion strengthening layer is 1.0 mol% to 1.2 mol% may include.

The step (S3) may be a step of depositing a tie coat layer on the resin layer using a sputtering method.

The step (S3) may be a step of forming the tie coat layer to a thickness in the range of 7 nm to 50 nm.

The step (S4) may include (S41) depositing a copper seed layer on the tie coat layer by a sputtering method; and (S42) plating a copper film layer on the copper seed layer by an electrolytic plating method.

In the method of manufacturing a printed circuit board according to an embodiment of the present invention, the tie coat layer and the copper layer provided in the flexible circuit copper clad laminate manufactured by the manufacturing method of the flexible circuit copper clad laminate according to the embodiment of the present invention are etched. to form a wiring pattern.

According to one aspect of the present invention, the adhesive force between the resin layer and the tie coat layer constituting the flexible circuit copper-clad laminate is strengthened, thereby improving the peel strength at high temperature, thereby securing excellent quality of the flexible circuit copper-clad laminate. .

According to another aspect of the present invention, by improving the quality of the flexible circuit copper-clad laminate, the quality of the printed circuit board manufactured by forming a wiring pattern on the copper layer of the flexible circuit copper-clad laminate can also be significantly improved.

1 is a cross-sectional view showing a flexible circuit copper-clad laminate according to an embodiment of the present invention.
2 is a flowchart illustrating a method of manufacturing a flexible circuit copper-clad laminate according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

A flexible circuit copper-clad laminate and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 .

1 is a cross-sectional view illustrating a flexible circuit copper-clad laminate according to an embodiment of the present invention, and FIG. 2 is a process diagram illustrating a method of manufacturing a flexible circuit copper-clad laminate according to an embodiment of the present invention.

1 and 2, the flexible circuit copper-clad laminate 10 according to an embodiment of the present invention includes a resin layer 1, an adhesive strength reinforcing layer 1a, a tie coat layer 2, and a copper layer 3 These are sequentially stacked.

The resin layer 1 corresponds to a single-layer or multi-layer film made of at least one of a thermosetting resin, a thermoplastic resin, a polyester resin, a polyimide resin, a condensate, or a mixture of at least two or more selected therefrom.

Examples of the thermosetting resin include phenol resins, phenolaldehyde resins, furan resins, aminoplast resins, alkyd resins, allyl resins, epoxy resins, epoxy prepregs, polyurethane resins, thermosetting polyester resins, silicone resins, etc. this can be used As the thermoplastic resin, polyethylene, polypropylene, ethylene/vinyl copolymer, ethylene acrylic acid copolymer, and the like may be used. As the polyester resin, those prepared from divalent aliphatic and aromatic carboxylic acids and diols or triols may be used. The polyimide resin is particularly useful, which is obtained through a reaction in which tetrabasic acid dianhydride is contacted with an aromatic diamine to yield a polyamic acid, which is then converted into a high molecular weight linear polyimide by heat or catalyst. can As the condensation polymer, polyamide, polyether imide, polysulfone, polyethersulfone, polybenzazole, aromatic polysulfone, and the like may be used.

The adhesion strengthening layer (1a) is formed on at least one surface of the resin layer (1) and is formed through a wet pretreatment process for the surface of the resin layer (1). That is, the polymer film constituting the resin layer 1 is subjected to a wet pre-treatment process prior to the formation of the tie-coat layer 2 in order to improve adhesion with the tie-coat layer 2, and according to this wet pre-treatment process, the resin layer An adhesive force strengthening layer (1a) is formed between (1) and the tie coat layer (2).

The adhesion-reinforcing layer (1a) contains silane, and in order to maximize the adhesion-reinforcing effect of the adhesion-reinforcing layer (1a), the thickness of the silane layer having a certain composition ratio in the layer formation process and the The concentration (mol%) may be controlled within a certain range.

That is, the thickness of the adhesion strengthening layer 1a is preferably limited to approximately 3 nm to 30 nm, and the concentration of silane contained in the material used for the preparation of the adhesion strengthening layer is limited to 1.0 mol% to 1.2 mol%. it is preferable

When the thickness of the silane is too thin, there is a problem that the pretreatment is not sufficiently performed, and when the thickness is too thick, the silane bond of the outermost layer is unstable and sufficient bonding strength is not secured. This weakening problem can occur.

In addition, when the concentration value of the silane is too small, there is a problem in that the pretreatment is not sufficiently performed. The adhesive strength may be adversely affected and a problem of lowering peel strength may occur.

The tie coat layer 2 may be made of an alloy containing nickel (Ni) as a main component, and is formed on at least one of both surfaces of the pre-treated resin layer 1 , that is, on the adhesion strengthening layer 1a. do.

The tie coat layer 2 may be deposited on the resin layer 1 by a sputtering method, which is a type of dry plating method, and is preferably formed to a thickness of approximately 7 nm to 50 nm. That is, when the thickness of the tie coat layer 2 is less than 7 nm, there is a risk of a decrease in peel strength during etching for forming a wiring pattern, and when it exceeds 50 nm, there is a problem in that the etching process is not easy.

The alloy constituting the tie coat layer 2 may further contain metals such as molybdenum (Mo) and/or niobium (Nb) and/or chromium (Cr) in addition to nickel.

The copper layer 3 is formed on the tie coat layer 2 and may include a copper seed layer 3a and a copper film layer 3b. The copper seed layer 3a is a layer formed by depositing on the tie coat layer 2 by a sputtering method, and may be formed to a thickness of approximately 60 nm to 1000 nm.

The coating layer 3b is a copper layer formed by an electrolytic plating method on the copper seed layer 3a, and is preferably formed to a thickness of about 8 μm to 16 μm, and more preferably about 10 μm to 14 μm thick. can be formed with

As described above, in the flexible circuit copper-clad laminate 10 according to an embodiment of the present invention, the adhesive strength through the step (S1) of preparing the resin layer 1 made of a polymer film, and pretreatment on at least one surface of the resin layer. forming a reinforcing layer (1a) (S2), forming a tie-coat layer (2) on the adhesion-reinforcing layer (1a) (S3), and forming a copper layer (3) on the tie-coat layer; can be manufactured through

The flexible circuit copper clad laminate 10 has excellent physical properties by controlling the thickness of the adhesive force reinforcing layer 1a and the silane content range of a material used for forming the adhesion reinforcing layer within a certain level.

Meanwhile, a desired wiring pattern can be formed by etching the copper layer 3 and the tie coat layer 2 of the flexible circuit copper clad laminate manufactured through the above process using a known method such as photo etching, thereby forming a printed circuit. A substrate (PCB) is obtained.

Hereinafter, experimental conditions and a method for evaluating physical properties for manufacturing the flexible circuit copper-clad laminate 10 will be described, and the physical properties of the flexible circuit copper-clad laminate manufactured as described above will be examined with reference to Tables 1 and 2.

Conditions of application substances

The composition of the silane used in the pretreatment: contains not more than 25% Si, not less than 40% C, not more than 3% O, and not more than 5% N, based on % Atomic.

Solvent for silane: IPA (isopropyl alcohol) is used.

manufacturing conditions

A wet pretreatment was performed on the polyimide film using a silane + solvent (IPA) material, and then a tie coat and a copper seed layer were deposited using sputtering. Then, plating was performed on the copper seed layer through an electroplating method. At this time, the thickness of the silane layer formed by the pretreatment was 3 to 30 nm, the thickness of the tie coat layer was 7 to 50 nm, the thickness of the copper seed layer was 60 nm to 1000 nm, and the thickness of the copper plating layer was 12 μm.

On the other hand, in the case of pretreatment using a silane-containing material, it was dried in an oven (about 120° C.) for about 5 minutes after coating using a wire bar (No. 8).

Method of evaluation of physical properties

Reflectance: The reflectance in the visible region of 330-750 nm in the sample 3 cm × 3 cm region was measured.

High-temperature peeling strength: After patterning a 12㎛-thick copper film layer-plated sample to become 1mm wide and 10cm long through the patterning process, measure the peel strength using Instron equipment at 180 degrees using the Instron equipment, and then measure the minimum and maximum peel strength The average value of 6 samples except for was measured.

Concentration of silane: The concentration was measured by analyzing the amount of light absorbed by the material using light having a specific wavelength of 400 nm using spectroscopic analysis (using SV2100 model manufactured by K-MAC).

Referring to Table 1 and Table 2, in the silane + solvent mixture used for pretreatment, the concentration of silane is maintained in the range of about 1.0 mol% to 1.2 mol%, and the thickness of the silane layer is maintained in the range of about 3 nm to 30 nm In this case, it can be seen that the high-temperature peel strength is significantly higher.

In particular, in Table 1, comparing the results according to Example 1 and Comparative Example 3, even when the thickness of the silane layer (adhesion strengthening layer) is in the range of 3 nm to 30 nm, the concentration of silane in the mixture of silane + solvent is 1.0 When it falls below mol%, it can be seen that the high-temperature peel strength significantly decreases.

Similarly, comparing the results according to Example 4 and Comparative Example 5, even when the thickness of the silane layer is in the range of 3 nm to 30 nm, high temperature peel strength when the concentration of silane in the mixture of silane + solvent exceeds 1.2 mol% It can be seen that there is a significant drop in In the case of high-temperature peel strength, it should be 0.65 kgf/cm or more, and this is because when the manufactured flexible circuit copper-clad laminate is used for circuit board manufacturing, it undergoes various heat treatment process steps such as a hot press process and a reflow process. This is because, if the high-temperature peeling strength is low during this process, defects may occur in the product.

On the other hand, in Table 2, comparing the results of Example 5 and Comparative Example 8, the thickness of the silane layer is less than 3 nm even when the concentration of silane in the mixture of silane + solvent is maintained in the range of 1.0 mol% to 1.2 mol%. It can be seen that when the thickness is thinned, the high-temperature peel strength is significantly lowered. Similarly, comparing the results of Example 11 and Comparative Example 10, even when the concentration of silane in the mixture of silane + solvent is maintained in the range of 1.0 mol% to 1.2 mol%, when the thickness of the silane layer becomes thicker than 30 nm It can be seen that the phenomenon that the high-temperature peel strength is significantly lowered occurs.

In addition, when water was used as a solvent (Comparative Examples 4 and 9) and when IPA was used (for example, Examples showing almost the same conditions as Comparative Examples 4 and 9, respectively, except for the solvent used) 4 and Example 6), it can be seen that the high-temperature peel strength is much better when IPA is used than when water is used as a solvent.

As described above, in the flexible circuit copper clad laminate 10 according to an embodiment of the present invention, the adhesive force made of silane between the resin layer 1 and the tie coat layer 2 through wet pretreatment for the resin layer 1 . The reinforcing layer 1a is formed, but the concentration of silane among the silane + solvent mixture used for pretreatment and the thickness of the formed adhesion reinforcing layer 1a are controlled within a certain range to have significantly improved high-temperature peel strength characteristics.

In addition, as the physical properties of the flexible circuit copper-clad laminate 10 are improved, the quality of the printed circuit board manufactured by forming a wiring pattern on the copper layer of the copper-clad laminate 10 can also be improved.

In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.

1: resin layer
1a: adhesion strengthening layer
2: tie coat layer
3: copper layer
3a: copper seed layer
3b: copper film layer
10: Flexible circuit copper clad laminate (FCCL)

Claims (10)

resin layer;
an adhesion strengthening layer containing silane as formed on at least one surface of the resin layer by a pretreatment operation;
a tie coat layer formed on the silane-containing adhesion strengthening layer; and
a copper layer formed on the tie coat layer;
The thickness of the adhesion strengthening layer is 3nm to 30nm,
The concentration of the silane is 1.0 mol% to 1.2 mol%,
The silane is a flexible circuit copper clad laminate having a composition containing not more than 25% Si, not less than 40% C, not less than 3% O, and not more than 5% N (% means atomic%). delete According to claim 1,
The copper layer is
a copper seed layer formed over the tie coat layer; and
and a copper film layer formed on the copper seed layer. According to claim 1,
A flexible circuit copper-clad laminate, characterized in that isopropyl alcohol is used as a solvent for the silane. According to claim 1,
The flexible circuit copper-clad laminate, characterized in that the resin layer is made of a polyimide resin. According to claim 1,
The tie coat layer,
A flexible circuit copper-clad laminate, characterized in that it is formed to a thickness in the range of 7nm to 50nm. A printed circuit board having a wiring pattern formed on a copper layer of the flexible circuit copper clad laminate according to claim 1 . (S1) forming a resin layer;
(S2) forming an adhesion strengthening layer containing silane by performing a wet pretreatment on at least one surface of the resin layer;
(S3) forming a tie coat layer on the adhesion strengthening layer; and
(S4) forming a copper layer on the tie coat layer;
includes,
The step (S2) includes controlling the thickness and concentration so that the thickness of the adhesion strengthening layer is 3 nm to 30 nm, and the concentration of silane is 1.0 mol% to 1.2 mol%,
The silane is a method of manufacturing a flexible circuit copper clad laminate having a composition containing 25% or less of Si, 40% or more of C, 3% or more of O, and 5% or less of N (% means atomic%). delete A method of manufacturing a printed circuit board comprising the step of forming a wiring pattern by etching the copper layer provided in the flexible circuit copper-clad laminate manufactured by the manufacturing method of the flexible circuit copper-clad laminate according to claim 8 .

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