KR101473859B1 - Prepreg, prepreg laminates, and metal clad laminates and print wiring board having the prepreg or the prepreg laminates - Google Patents

Abstract

A prepreg, a prepreg laminate, and a metal-clad laminate employing the prepreg or prepreg laminate and a printed wiring board are disclosed. The disclosed metal-clad laminate includes a substrate and a prepreg including a resin impregnated or coated with the substrate, or a prepreg laminate including at least one prepreg and a prepreg laminate disposed on one side or both sides of the prepreg or the prepreg laminate Wherein the metal thin film has a surface portion having at least one convex portion satisfying the following conditions on one surface or both surfaces thereof. 0 <L ' ₁ / L' ₂ <1. Here, L ' ₁ is the width of the convex portion excluding L' ₂ , and L ' ₂ is the length (maximum width) of the base of the convex portion. Therefore, the disclosed prepreg can improve the adhesion to the metal thin film. Further, the interlayer peeling strength of the metal-clad laminate and the printed wiring board employing the prepreg can be improved.

Description

Prepregs, prepreg laminates, and metal clad laminates and print wiring boards having the prepreg or the prepreg laminates, and prepregs and prepreg laminates,

The present invention relates to a prepreg, a prepreg laminate, and a metal-clad laminate and a printed wiring board employing the prepreg or prepreg laminate, and more particularly to a prepreg or prepreg having a surface portion having at least one convex portion, A leg laminate and a surface portion having at least one convex portion and / or a prepreg or prepreg laminate, thereby improving interlaminar peel strength and a printed wiring board having the same.

2. Description of the Related Art Recently, with the miniaturization and multifunctionalization of electronic devices, printed wiring boards have been increasingly densified and miniaturized. Metal-clad laminated sheets are excellent in stamping processability, drilling processability, and are inexpensive and widely used as substrates for printed wiring boards in electronic devices.

Such a metal foil laminate for a printed wiring board includes a prepreg and a metal foil laminated on the prepreg.

The prepreg is generally produced by impregnating a base material such as a woven fabric or a nonwoven fabric with a resin derived from epoxy or bismaleimide triazine. When a curable resin is used in preparing the prepreg, a step of semi-curing the impregnated or coated resin is added to the substrate. Thereafter, a metal thin film is laminated on the prepreg to produce a metal foil-clad laminate. When a curable resin is used in preparing the prepreg, a step of curing the resin in the prepreg in which the metal thin film is laminated is added.

The metal-clad laminate thus produced is thinned and subjected to a high-temperature process such as a reflow process at 270 ° C. During such a high-temperature process, the metal-clad laminate in the form of a thin film has a problem of interlayer peeling due to a difference in thermal expansion coefficient between the prepreg and the metal thin film . In addition, such delamination is accelerated when the metal-clad laminate is exposed to a use environment in which temperature and humidity vary widely.

In order to solve the above problems, a method of improving the peeling strength of the finished metal foil laminate by changing the heating temperature or the composition of the resin when the metal foil is laminated by heat pressing on the prepreg has been sought. However, the specifications of presses usable in hot-pressing are limited, and composition changes of the resin can be performed only within a limited range, and thus it is not a fundamental solution.

The present invention provides a prepreg or prepreg laminate capable of improving adhesion to a metal thin film.

The present invention also provides a metal-clad laminate and a printed wiring board improved in interlaminar peeling strength.

According to an aspect of the present invention,

A prepreg comprising a substrate and a resin impregnated or coated on the substrate,

Wherein the prepreg includes a surface portion having at least one convex portion satisfying the following conditions on one or both surfaces thereof:

0 < L ₁ / L ₂ < 1.

Here, L ₁ is the width of the convex portion excluding L ₂ , and L ₂ is the length (maximum width) of the base of the convex portion.

According to another aspect of the present invention,

There is provided a prepreg laminate including at least one prepreg according to the above embodiment.

According to another aspect of the present invention,

A prepreg comprising a base material and a resin impregnated or coated with the base material, or a prepreg laminate comprising at least one of the prepregs; And

And a metal thin film disposed on one side or both sides of the prepreg or the prepreg laminate,

Wherein the metal thin film has a surface portion having at least one convex portion satisfying the following conditions on one surface or both surfaces thereof:

0 <L ' ₁ / L' ₂ <1.

Here, L ' ₁ is the width of the convex portion excluding L' ₂ , and L ' ₂ is the length (maximum width) of the base of the convex portion.

According to another aspect of the present invention,

A printed wiring board obtained by circuit processing of the metal-clad laminate according to the above embodiment is provided.

According to another aspect of the present invention,

A metal-clad laminate including a printed wiring board according to the above-described embodiment and a prepreg or a prepreg laminate disposed on at least one side of the printed wiring board and having a metal thin film disposed on the prepreg or the prepreg laminate do.

According to the present invention, it is possible to provide a prepreg or prepreg laminate capable of improving adhesion to a metal thin film.

Further, according to the present invention, a metal-clad laminate and a printed wiring board with improved interlayer peel strength can be provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a partial perspective view showing a typical prepreg.

Referring to Figure 1, a typical prepreg 10 includes a substrate and a resin impregnated or applied to the substrate, though not shown separately here.

As the above substrate, a glass fiber fabric, a glass fiber nonwoven fabric, a carbon fiber fabric, or the like can be used. It is desirable to use glass wool in terms of mechanical, electrical characteristics and economy.

As the resin, a curable resin or a liquid crystal polymer may be used.

The prepreg 10 is prepared by impregnating or applying a resin solution in which the resin is dissolved in a solvent, followed by drying and rolling. In order to control the dielectric constant and the thermal expansion coefficient of the resin solution, an organic filler such as silica, aluminum hydroxide, inorganic filler of calcium carbonate, cured epoxy, crosslinked acryl, etc. may be added to the resin solution so long as the object of the invention is not impaired.

The drying and rolling processes may be sequential or simultaneous. The solvent contained in the prepreg 10 is removed through the drying process, and the prepreg 10 has a desired thickness through the rolling process. The rolling process may be performed under the conditions that, for example, the rolling roll pressure is 10 kgf / cm 2, the rolling roll temperature is 120 ° C, and the prepreg temperature is 200 ° C. The method for removing the solvent is not particularly limited, but is preferably carried out by solvent evaporation.

2 is a partial perspective view illustrating a prepreg according to an embodiment of the present invention.

2, the prepreg 11 according to the present embodiment has a surface portion 11a having at least one convex portion P satisfying the following conditions on both sides thereof:

0 < L ₁ / L ₂ < 1.

Here, L ₁ is the width of the convex portion P excluding L ₂ . The base of the convex portion P is a line connecting the two lowest points of the contour of the convex portion P and has the same size as the maximum width of the convex portion P. [

It is preferable that the height H of the convex portion P of the prepreg 11 always satisfies the following condition:

 0 < H &amp;le; 10 mu m.

If the height H is more than 10 mu m, the convex portion may be folded at the time of laminating the metal thin film described later, or the thickness of the prepreg may increase after lamination of the metal thin film to exceed the allowable thickness of the final printed wiring board not.

The plurality of convex portions P included in the surface portion 11a may be the same in size or the size of the at least one convex portion P may be different from the size of the remaining convex portion P. [ In addition, the shape of the surface portion 11a may be regular or irregular. In addition, the surface portion 11a may include a small branch-shaped protrusion of 1 mu m or less. By providing the surface portion 11a having the above-described structure, when the metal thin film (20 in FIG. 4) is stacked on the prepreg 11, the peeling strength between the layers can be improved by increasing the adhesive force. Will be described later. The surface portion 11a may be formed only on one side of the prepreg 11, and the other side may be formed with a flat surface portion.

The surface portion 11a having the above-described structure can be realized by performing the surface treatment of the surface of the prepreg 11 by electrochemical treatment or thermomechanical processing. For example, after the prepreg is manufactured, the prepreg is dried to remove the solvent, and then the dried prepreg is brought into contact with a metal roll having a concave shape (i.e., a shape opposite to the surface portion 11a) The surface portion 11a can be formed by heating and pressing. In this case, it is preferable to raise the temperature of the metal surface portion in contact with the prepreg to the melting temperature of the resin contained in the prepreg. At this time, the pressure is a level higher than the normal pressure, so long as the surface portion of the metal roll is separated from the surface portion of the prepreg so long as the resin is not left on the surface portion of the metal roll.

According to the present invention, a prepreg laminate (not shown) formed by laminating at least one prepreg 11 of Fig. 2 can be provided. Also, one or more prepregs 10 shown in FIG. 1 may be included in the prepreg laminate.

FIG. 3 is a cross-sectional view illustrating a metal foil laminates according to an embodiment of the present invention including the prepreg of FIG. 1;

3, the metal-clad laminate 100 according to the present embodiment includes a prepreg 10 and a metal thin film 20 disposed on both sides of the prepreg 10. However, the metal thin film 20 may be disposed on only one side of the prepreg 10.

The metal foil 20 has a surface portion 20a having at least one convex portion P 'satisfying the following conditions on one or both surfaces thereof:

0 <L ' ₁ / L' ₂ <1.

Here, L ' ₁ is the width of the convex portion excluding L' ₂ . The base of the convex portion P 'is a line connecting the two low points of the contour of the convex portion P' and has the same size as the maximum width of the convex portion P '.

It is preferable that the height H 'of the convex portion P' of the metal thin film 20 always satisfies the following condition:

 0 < H &amp;le; 10 mu m.

When the height H 'exceeds 10 탆, the convex portion P' is folded when the metal thin film is laminated on one side of the prepreg, or when the metal thin film is laminated on the substrate (for example, glass cloth) of the prepreg It may become a cause of defects and the thickness of the prepreg may increase after the metal thin film is laminated, which may exceed the allowable thickness of the final printed wiring board.

The plurality of convex portions P 'included in the surface portion 20a may be the same in size and the size of one or more convex portions P' may be different from the size of the remaining convex portions P ' It is possible. In addition, the shape of the surface portion 20a may be regular or irregular. In addition, the surface portion 20a may include a small branch-shaped protrusion of 1 mu m or less. When the metal thin film 20 is laminated on the prepreg 10, the resin contained in the prepreg 10 is prevented from being peeled off from the convex portions P ' And smoothly penetrates into the space to evenly adhere to the surface portion 20a. Therefore, the adhesive force between the prepreg 10 and the metal thin film 20 increases, and the peel strength between the layers can be improved. Specifically, in the metal-clad laminate 100 according to this embodiment, the peel strength between the prepreg 10 and the metal thin film 20 bonded thereto is 0.8 kg / cm ² or more.

The surface portion 20a may be formed on both sides of the metal thin film 20 depending on the purpose of use. The metal plate laminate 100 may include a prepreg laminate (not shown) in which a predetermined number of the prepregs 10 are laminated instead of the single prepreg 10.

The surface portion 20a having such a structure can be realized by performing surface treatment by electrochemical treatment or thermomechanical processing on the surface of the metal thin film 20. [ An example of a method of forming the surface portion 20a of the metal thin film 20 will be described below. That is, for example, when the metal thin film is a copper foil, a copper foil is obtained through a process of reducing copper ion to a metal by an electrolytic method, followed by washing with water and drying. Subsequently, on the surface of the copper foil in contact with the prepreg, a precious metal such as platinum is discretely formed by sputtering or the like, and then oxidized with an alkaline solution containing an oxidizing agent to form copper oxide crystals, Thereby producing a copper foil surface portion having a part. Subsequently, the convex portion formed by the copper oxide crystal thus formed is subjected to a reduction treatment using a solution for reduction treatment to change it to the convex portion of the metal copper.

The metal-clad laminate 100 having the above-described structure is formed on one or both surfaces of a prepreg 10 or a prepreg laminate (not shown) in which a predetermined number of the prepregs are laminated ), And heating and pressing them all.

FIG. 4 is a cross-sectional view illustrating a metal foil laminates according to another embodiment of the present invention including the prepreg of FIG. 2;

The metal-clad laminate 200 of FIG. 4 includes a metal thin film 20 having a surface portion 20a having at least one convex portion on one side or both sides. The metal foil laminates 200 according to the present embodiment include an adhesive layer 12 and / or a resin layer 30 interposed between the prepregs 11 and the metal foil 20 to improve the adhesion between the prepregs 11 and the metal foil 20. do. In addition, although not shown here, the metal-clad laminate according to one embodiment of the present invention may include a prepreg laminate in which a predetermined number of prepregs 11 are laminated instead of the prepreg 11. According to another embodiment of the present invention, a prepreg 11 may be replaced with a prepreg having a surface portion having a flat surface on at least one side and at least one convex portion on the other side, or a prepreg laminate .

The metal-clad laminate 200 having the above-described structure is formed by applying an adhesive or arranging a resin layer 30 on one side or both sides of a prepreg 11 or a prepreg laminate (not shown) Next, a metal thin film 20 such as a copper foil, a silver foil or an aluminum foil may be disposed on the adhesive layer 12 or the resin layer 30, and the whole may be heated and pressed.

In addition, the metal-clad laminate according to another embodiment of the present invention may include a prepreg or a prepreg laminate in which a surface portion having a flat surface and at least one convex portion on the other surface is formed instead of the prepreg 11 . When the prepreg or prepreg laminate having a flat surface portion and the metal thin film having the surface portion having at least one convex portion are in contact with each other, the adhesive layer and the resin layer may not be interposed therebetween.

FIG. 5 is a cross-sectional view illustrating a printed wiring board according to an embodiment of the present invention including the prepreg of FIG. 1; The same reference numerals as in the drawings shown above refer to the same or a part of the same member.

The printed wiring board 40 according to this embodiment includes the same metal-clad laminate as the metal-clad laminate 100 of Fig. The printed wiring board 40 can be obtained by placing the metal foil 20 on both sides of the prepreg 10 and heating and pressing the same to form the circuit 40a on the metal foil 20. The formation of the circuit can be performed by a conventionally known method such as the subtractive method. A through hole 50 penetrating the prepreg 10 and the metal foil 20 is formed in the frit wiring board 40 and a metal plating layer 60 is coated on the inner wall of the through hole 50 . In addition, a predetermined circuit component (not shown) is usually mounted on the printed wiring board 40. According to the present invention, a printed wiring board including a modification of the metal-clad laminate 100 of Fig. 3 or the metal-clad laminate 200 of Fig. 4 or a modification thereof may be provided although not shown here.

6 is a cross-sectional view illustrating a metal-clad laminate according to an embodiment of the present invention including the printed wiring board of FIG. The same reference numerals as in the drawings shown above refer to the same or a part of the same member.

The metal-clad laminate 300 according to this embodiment includes the printed circuit board 40 'having the circuit portion 40'a and the surface portion 20a having at least one convex portion on both sides, the prepreg 10, And a metal thin film 20 having a surface portion 20a having at least one convex portion on one surface or both surfaces thereof. Specifically, the metal-clad laminate 300 includes two prepregs 10 laminated on both sides of a printed wiring board 40 ', and two metal thin films 20 laminated on the outer side of the prepreg 10 ). On the other hand, the circuit 40'a may be formed on only one side of the printed wiring board 40 '. In addition, the metal-clad laminate 300 may have one or more printed wiring boards and prepregs alternately stacked one on another between the prepreg 10 and the printed-wiring board 40 '.

The metal foil laminates and printed wiring boards employing prepregs and metal foils having the above-described structure have an increased adhesive strength between the prepreg and the metal foil, and therefore, even when exposed to high temperatures during the manufacturing process, Will not happen.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Example

Production Example 1: Preparation of prepregs having flat surface portions on both surfaces

<Selection of description>

A glass fiber cloth (IPC 2116) having a thickness of 100 mu m and a unit area weight of 107 g / m &lt; 2 &gt; was used as a substrate for producing the prepreg.

&Lt; Preparation of liquid crystal polymer varnish &

100 parts by weight of an aromatic polyester amide (number average molecular weight 10,000) as a liquid crystal polymer resin and 400 parts by weight of n-methylpyrrolidone as a solvent were blended and stirred at 80 DEG C to prepare a liquid crystal polymer varnish.

&Lt; Preparation of prepreg >

The impregnation vessel was filled with the liquid crystal polymer varnish, passed through the substrate, impregnated, and dried in a hot air circulating dryer at 150 캜 for 3 minutes to prepare a prepreg. In order to form convex portions on the dried prepreg, a plurality of conical grooves having a depth of 3 占 퐉 and a width gradually narrower depending on the depth are formed after the prepreg is stepwise heated to 200 占 폚 by radiant heat of an infrared heater and heat- Rolled using a roll. At the time of rolling, the temperature of the roll was set to 290 DEG C and the pressure was set to 20 Kgf / cm &lt; 2 &gt; to form convex portions of the prepreg.

Example 1: Preparation of a prepreg having surface portions each having a plurality of convex portions on both surfaces

A prepreg having a surface portion having a plurality of convex portions on both surfaces by simultaneously heating and rolling both sides of the prepreg using a pair of rolls having a plurality of conical grooves each having a depth of 3 占 퐉 and a width gradually becoming narrower depending on the depth, . Other conditions were the same as in Example 1.

Example 2-1: Fabrication of metal-clad laminate having the structure of Fig. 3

&Lt; Preparation of metal thin film &

Copper foil was prepared using a plating bath containing copper sulfate (400 g / liter) and sulfuric acid (100 g / liter) maintained at a temperature of 65 ° C. At this time, the current density and the chloride ion concentration were adjusted to 100 A / dm ² and 20 ppm, respectively. Subsequently, platinum is discretely formed on the surface portion of the copper foil by sputtering and then oxidized with an alkaline solution containing sodium chlorate as an oxidizing agent to form copper oxide crystals to form a copper foil surface portion having a plurality of convex portions . Subsequently, the convex portion formed by the copper oxide crystal thus formed was subjected to a reduction treatment using HIST-100 (manufactured by Hitachi Chemical Co., Ltd.) as a reducing treatment solution to change the convex portion of the metal copper.

&Lt; Preparation of Metal Laminates &

The copper foil as prepared above was placed on both sides of the prepreg prepared in Production Example 1, and laminated under pressure at a temperature of 200 캜 and a pressure of 40 kgf / cm 2 for 1 hour using a hot plate press to produce a metal foil laminates.

Example 2-2: Fabrication of metal-clad laminate having the structure of Fig. 4

An adhesive (KODO CHEMICAL, YD-136) was applied to both sides of the prepreg prepared as in Example 1, then the same copper foil as that used in Example 2-1 was placed on the adhesive layer, And laminated under pressure at a temperature of 260 캜 under a pressure of 30 kgf / cm 2 for 1 hour to produce a metal-clad laminate.

Comparative Example 2-1: Fabrication of metal-clad laminate

A metal thin film (3EC-3, manufactured by Mitsui Mining &amp; Mining Co., Ltd.) having flat surface portions on both sides was placed on both sides of the prepreg prepared as in Production Example 1, and the temperature was 200 ° C and the pressure was 40 kgf / Under pressure and pressure for 1 hour to form a metal-clad laminate.

Evaluation test

The peeling strength between the copper foil and the prepreg was measured on the metal foil laminates of Examples 2-1 to 2-2 and Comparative Example 2-1, and the results are shown in Table 1 below. The peel strength measurement method was IPC-TM-650 2.4.8.

[Table 1]

division Example 2-1 Example 2-2 Comparative Example 2-1 Peel strength
(Kg / cm ² ) 1.2 1.3 0.6

Referring to Table 1, it can be seen that the peel strength of the metal foil laminates according to Examples 2-1 to 2-2 is much larger than the peel strength of the metal foil laminates according to Comparative Example 2-1.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed 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.

1 is a partial perspective view showing a typical prepreg.

2 is a partial perspective view illustrating a prepreg according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a metal foil laminates according to an embodiment of the present invention including the prepreg of FIG. 1;

FIG. 4 is a cross-sectional view illustrating a metal foil laminates according to another embodiment of the present invention including the prepreg of FIG. 2;

FIG. 5 is a cross-sectional view illustrating a printed wiring board according to an embodiment of the present invention including the prepreg of FIG. 1;

6 is a cross-sectional view illustrating a metal-clad laminate according to an embodiment of the present invention including the printed wiring board of FIG.

Description of the Related Art

10, 11: prepregs 11a, 20a: surface portions

12: adhesive layer 20: metal thin film

30: resin layer 40: printed wiring board

50: through hole 60: metal plating layer

100, 200, 300: metal foil laminates

Claims (11)

delete delete delete A prepreg comprising a base material and a resin impregnated or coated with the base material, or a prepreg laminate comprising at least one of the prepregs; And The metal foil laminate comprising a metal foil disposed on one side or both sides of the prepreg or the prepreg laminate, Wherein the metal thin film has a surface portion having at least one convex portion satisfying the following condition on one surface or both surfaces thereof, 0 <L ' ₁ / L' ₂ <1. Here, L ' ₁ is the width of the convex portion excluding L' ₂ , and L ' ₂ is the length (maximum width) of the base of the convex portion.  The height H 'of the convex portion of the metal thin film always satisfies the following condition:  0 < H &amp;le; 10 mu m. delete 5. The method of claim 4, Wherein the prepreg or the prepreg laminate has flat surface portions on both sides thereof. 5. The method of claim 4, Wherein the prepreg or the prepreg laminate has a surface portion having at least one convex portion satisfying the following conditions on one or both surfaces thereof: 0 < L ₁ / L ₂ < 1. Here, L ₁ is the width of the convex portion excluding L ₂ , and L ₂ is the length (maximum width) of the base of the convex portion. 8. The method of claim 7, Wherein the height (H) of the convex portion of the prepreg or the prepreg laminate always satisfies the following condition:  0 < H &amp;le; 10 mu m. 8. The method of claim 7, Further comprising a resin layer or an adhesive layer disposed between the prepreg or the prepreg laminate and the metal foil. A printed wiring board obtained by circuit processing a metal-clad laminate according to any one of claims 4 and 6 to 9. A metal-clad laminate comprising a printed wiring board according to claim 10 and a prepreg or prepreg laminate disposed on at least one side of the printed wiring board, and a metal thin film disposed on the prepreg or the prepreg laminate.

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