KR102173113B1 - Method for manufacturing a metal clad laminate - Google Patents

Abstract

The present invention relates to a method of manufacturing a thin metal laminate, and more specifically, a protective pad used to protect the thin metal laminate in a pressing process and transmit a uniform pressure to each part when manufacturing the thin metal laminate. By processing the edge of the material in a non-linear manner, the difference in surface pressure that may occur in the laminating process is effectively resolved.

Description

Manufacturing method of thin metal laminated plate {METHOD FOR MANUFACTURING A METAL CLAD LAMINATE}

The present invention relates to a method for manufacturing a thin metal laminate.

Due to the development of electronic devices, a variety of shapes and sizes of printed circuit boards used for manufacturing electronic devices is required.

In a printed circuit board, wiring layers for circuit connection and insulating layers serving as interlayer insulation are alternately stacked. The wiring layer is generally formed of a conductive material such as metal, and the insulating layer is formed of a non-conductive polymer resin.

In this case, the printed circuit board needs to keep the thickness of the insulating layer thin in order to reduce the thickness, but there is a problem that the processing of the product becomes difficult as the thickness of the insulating layer decreases.

In particular, electrical, thermal, and mechanical properties are degraded because it is difficult to control the properties of the insulating layer, which has a lower coefficient of thermal expansion (Low CTE), a high glass transition temperature (Hign Tg), and a high modulus than a metal wiring layer. do.

In addition, since printed circuit boards are used in various electronic products, it is common to stack multiple layers for wiring design, but in the high temperature and high pressure applied during stacking, defects occur in the bonding of the prepreg and the metal foil. Alternatively, there is a problem that deformation occurs at the edge of the joint depending on the alignment state.

Accordingly, there is a need for a method of manufacturing a thin metal laminate to manufacture a multilayer printed circuit board capable of maintaining excellent physical properties even in a high temperature and high pressure environment during lamination.

The present invention provides a thin metal laminate capable of maintaining excellent physical properties even in a high temperature and high pressure situation applied when laminating a plurality of layers, and a method of manufacturing a thin metal laminate.

The present invention,

A) laminating one or more prepregs on a two-dimensional sheet-shaped metal foil;

B) laminating a metal foil on the prepreg to form a preliminary metal foil laminate; And

C) pressing the preliminary thin metal laminate to completely cure the prepreg;

C-1) In the pressing process, the preliminary metal foil laminate is subjected to a process of applying a protective pad in the shape of a two-dimensional sheet to both surfaces of the preliminary metal laminate and then pressing;

C-2) The protective pad provides a method of manufacturing a thin metal laminate using a non-linear edge.

According to the present invention, even in a situation of high temperature and high pressure applied when stacking multiple layers, surface pressure is constantly applied to each part, so that excellent physical properties can be maintained, thereby preventing a bonding failure between the prepreg and the metal foil. There will be.

1 is a diagram schematically showing a method of manufacturing a thin metal laminate according to an embodiment of the present invention.
2 is a photograph showing a shape in which an edge portion of a protective pad is non-linearly processed in a method of manufacturing a thin metal laminate according to an embodiment of the present invention.
3 is an enlarged photograph of a shape in which an edge portion of a protective pad is nonlinearly processed in a method of manufacturing a thin metal laminate according to an exemplary embodiment of the present invention.
4 is a photograph of a conventional protective pad in which the edge portion is not processed nonlinearly.
5 is a graph showing a difference in pressure applied to a center portion and an edge portion of a prepreg in a method of manufacturing a thin metal laminate according to an embodiment of the present invention.
6 is a graph showing the thickness distribution of each portion in the thin metal laminate manufactured according to Examples and Comparative Examples of the present invention.
7 is a photograph showing the surface conditions of the thin metal laminates manufactured according to Examples and Comparative Examples of the present invention.

The manufacturing method of the thin metal laminate of the present invention,

A) laminating one or more prepregs on a two-dimensional sheet-shaped metal foil;

B) laminating a metal foil on the prepreg to form a preliminary metal foil laminate; And

C) pressing the preliminary thin metal laminate to completely cure the prepreg;

C-1) In the pressing process, the preliminary metal foil laminate is subjected to a process of applying a protective pad in the shape of a two-dimensional sheet to both surfaces of the preliminary metal laminate and then pressing;

C-2) The protective pad has a non-linear edge.

In addition, terms used in the present specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise", "include" or "have" are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, elements, or combinations thereof is not preliminarily excluded.

In addition, in the present invention, when each layer or element is referred to as being formed “on” or “on” each layer or element, it means that each layer or element is directly formed on each layer or element, or It means that a layer or element may be additionally formed between each layer, on the object, or on the substrate.

Hereinafter, the present invention will be described in detail.

A method of manufacturing a thin metal laminate according to an aspect of the present invention,

A) laminating one or more prepregs on a two-dimensional sheet-shaped metal foil;

B) laminating a metal foil on the prepreg to form a preliminary metal foil laminate; And

C) pressing the preliminary thin metal laminate to completely cure the prepreg;

C-1) In the pressing process, the preliminary metal foil laminate is subjected to a process of applying a protective pad in the shape of a two-dimensional sheet to both surfaces of the preliminary metal laminate and then pressing;

C-2) The protective pad uses a non-linear edge.

Terms used in this specification are as follows.

In the present invention, the term "Metal Clad Laminate" means a plate including an insulating core and a metal layer laminated on one or both sides of the insulating core, and an original plate for manufacturing a printed circuit board That is, it is used as a concept including a copper clad laminate (CCL), which is used to manufacture a PCB original plate. In this case, the insulating core may be formed by the prepreg described in the present invention.

In addition, in the present specification, the term "Prepreg" is used as an insulating layer material when manufacturing a printed circuit board (PCB), which is used as an electrical wiring board, and is preimpregnated with a reinforcing fiber component. In the form of a sheet of insulating resin, it means that the insulating resin matrix component is in a semi-cured state in which complete curing is not performed, that is, in a state of B-stage.

According to an example, the prepreg may include an insulating resin and a reinforcing fiber impregnated in the insulating resin.

The insulating resin is not particularly limited as long as it is an insulating resin used for manufacturing a printed circuit board in the technical field to which the present invention pertains, but it may be preferable to include a thermosetting resin.

Specific examples of such thermosetting resins include urea resin, melamine resin, bismarimide resin, polyurethane resin, resin having a benzoxazine ring, cyanate ester resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin and bisphenol. And a copolymerized epoxy resin of S and bisphenol F, and the like, which may be used alone or in combination of one or more, but the present invention is not limited thereto.

In addition, the reinforcing fibers impregnated in the insulating resin are for improving the mechanical properties and insulating properties of the circuit board to be manufactured, and synthetic resin fibers or glass fibers may be used.

In addition, these reinforcing fibers may be linear, or may be used in the form of a woven fabric with each fiber crossing each other, and it may be preferable to be woven in 1 to 3 rows.

In a printed circuit board actually used for a number of electronic components, conductive layers and insulating layers are alternately stacked for various wiring designs, and these conductive layers and insulating layers are stacked in one or multiple layers.

In general, when manufacturing such a metal clad laminate or a multi-layer printed circuit board, one or more prepregs for forming an insulating layer are laminated on the metal foil, and It is manufactured by re-laminating a metal foil for forming a distribution board on the leg.

1 is a diagram schematically showing a method of manufacturing a thin metal laminate according to an embodiment of the present invention.

Referring to FIG. 1, on the metal foil 120 of a two-dimensional sheet shape, one or more layers of the prepreg 110 are laminated, and B) the metal foil 120 is laminated again on the prepreg 110, After configuring the preliminary metal thin laminate, it can be seen that the prepreg is completely cured by pressing the preliminary metal thin laminate.

As described above, the prepreg used at this time is used in a semi-cured state in which the insulating resin matrix component is not completely cured, that is, in a B-stage state, and a metal foil is laminated thereon, and then it is under high temperature conditions. By pressing in, the prepreg is bonded by a method of curing (C-Stage).

However, in the bonding process as described above, deformation may occur in the shape of the prepreg and the metal due to environmental conditions of high temperature and high pressure, and fine voids may occur at the prepreg-metal bonding interface, resulting in poor bonding. Therefore, in order to prevent deformation of the prepreg and the metal from high temperature and high pressure, and to evenly transmit pressure to each part, a protective pad is used.

In recent years, printed circuit boards are used in various types of electronic products, and as the size of products such as large-sized home appliances increases, the printed circuit boards used therein are also required to have a size larger than a certain size.

However, when manufacturing a printed circuit board having a large area, a difference occurs in the pressure (surface pressure) applied to the center and the edge in the process of laminating a prepreg and a metal layer as described above and laminating in a high temperature and high pressure environment. Is done.

Due to this difference, there may be a variation in the thickness of the center and the edge of the printed circuit board to be manufactured. In addition, due to insufficient resin flow due to pressure unevenness in the prepreg (B-stage) that was not completely cured, the metal layer and the prepreg A so-called void defect may occur in which minute voids occur at the bonding interface of the legs.

In order to solve this problem, there have been attempts to variously change the material, thickness, and width of the prepreg, but this is a problem caused by home appliances that become larger and thinner, and there is a fundamental limitation in solving it by the above method.

According to an aspect of the present invention,

A) laminating one or more prepregs on a two-dimensional sheet-shaped metal foil;

B) laminating a metal foil on the prepreg to form a preliminary metal foil laminate; And

C) pressing the preliminary thin metal laminate to completely cure the prepreg;

C-1) In the pressing process, the preliminary metal foil laminate is subjected to a process of applying a protective pad in the shape of a two-dimensional sheet to both surfaces of the preliminary metal laminate and then pressing;

C-2) The protective pad has a non-linear edge;

It provides a method of manufacturing a thin metal laminate.

2 is a photograph showing a shape in which an edge portion of a protective pad used in a laminating process is processed in a non-linear manner in a method of manufacturing a thin metal laminate according to an embodiment of the present invention.

Referring to FIG. 2, it can be clearly confirmed that the edge portion of the protective pad is processed into a triangular irregular shape, and thus has a cogwheel shape.

The inventors of the present invention, as described above, when processing the edge of the protective pad in a non-linear manner, in the lamination process in a high temperature and high pressure environment, it is possible to evenly transfer pressure to each portion of the metal foil and the prepreg, and the surface pressure of the center and the edge It was found that the difference could be effectively resolved, and the present invention was completed.

That is, when the edge of the wide protective pad is nonlinearly processed, even if the surface pressure difference occurs at the center and the edge, the nonlinearly processed edge portion is deformed more flexibly than the existing linear shape and the surface pressure difference is resolved. In this way, thickness deviation and void generation can be prevented.

Here, the two-dimensional sheet shape means that it has a thin thickness compared to a large area, and the shape has a sheet or film shape, and assuming a flat figure, a triangle, a square, a pentagon, etc. It means to have the shape of a polygon or an ellipse.

In addition, the edge part of a two-dimensional sheet shape means the side of the said planar figure, or the arc of an ellipse.

The edge of the two-dimensional sheet-shaped protective pad may be processed into a curved uneven shape or a polygonal uneven shape.

In the case of curved irregularities, curves such as the same or different arcs or parabolic ellipses are connected in the same or opposite phases to form a wave shape in the form of a sin curve or a wave shape in the form of a sin absolute value curve. have.

In the case of a polygonal irregular shape, the edges may be connected in a triangular or square shape to form a cogwheel or a saw blade shape.

In this case, the metal foil may include at least one selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), aluminum (Al), and copper (Cu), but is limited thereto. It is not, and any metal used as a wiring or a conductive layer of a circuit board can be used without any particular limitation.

According to an embodiment of the invention, the protective pad may be in the form of a rectangular sheet, and the edge may be processed in a non-linear state in the form of curved irregularities or polygonal irregularities, and the width and height of the curved irregularities or polygonal irregularities are independently As such, it may be desirable to be about 1/50 to about 1/500 of the side length of the thin metal laminate.

Here, the width of the irregularities refers to the distance from the start of the protrusion of one irregularity to the start of the next projection, and the height of the irregularities is from the most protruding part of any one irregularity. It means the distance to the depression.

As described above, when the width and height of the curved or polygonal irregularities, each independently, are about 1/50 to about 1/500 of the side length of the thin metal laminate, the difference in surface pressure that may occur in the laminating process can be effectively resolved. You will be able to. If it is out of the above range, the effect of solving the difference in surface pressure due to the uneven processing may be reduced, the additional process burden due to the uneven processing may be increased, and also, due to the loss of the prepreg due to the processing of the uneven part, economic efficiency may be lowered. have.

According to another embodiment of the present invention, the protective pad may be made of a heat-resistant resin, and specifically, a temperature condition of about 150 to about 270°C, or about 200 to about 250°C, that is, a temperature condition of a laminating process Heat-resistant resins that can withstand are used without special restrictions. Specifically, examples of such heat-resistant resins include polyimide-based resins, polyamide-imide-based resins, polyphenylene sulfide-based resins, polyketone-based resins, or carbon fibers. In addition to heat resistance, pressure applied in the laminating process In consideration of mechanical properties such as strength to withstand the material, it is preferable to use carbon fiber or an aromatic amide resin (eg, aramid resin).

In addition, as a method of processing the edge of such a protective pad, a general method used for cutting and cutting the resin in the technical field to which the present invention pertains may be used.

According to an embodiment of the invention, the step of applying the pressure may be preferably performed under a pressure condition of about 1 to 10 MPa, preferably, about 4 to 5 MPa, and about 150 to about 270°C, or about Although it may be desirable to proceed under a temperature condition of 200 to about 250° C., it is not necessarily limited thereto, and the temperature and pressure conditions may vary depending on the resin characteristics, size, and thickness of the prepreg to be used.

As described above, in the case of the present invention, since the difference in surface pressure in the laminating process can be eliminated due to the nonlinear processing portion of the edge of the prepreg, the difference in thickness between the center and the edge may hardly occur.

Specifically, according to another embodiment of the present invention, in the thin metal laminate manufactured by the above method, a thickness standard deviation value of each portion may be about 0.7% or less with respect to an average thickness.

3 is an enlarged photograph of a shape in which an edge portion of a protective pad is processed in a non-linear manner in a manufacturing method according to an embodiment of the present invention.

Referring to FIG. 3, it can be clearly confirmed that the edge portion of the protective pad is processed in a triangular uneven shape to have a toothed shape.

In addition, in the case of the above embodiment, the size of the protective pad is 1280mm*2100mm, and it can be clearly confirmed that the width and height of the irregularities are each independently about 10mm.

4 is a photograph of an existing prepreg in which the edge portion is not processed nonlinearly.

In addition, according to an embodiment of the present invention, the steps of laminating one or more prepregs on the metal foil and forming a preliminary metal foil laminate by laminating a metal foil on the prepreg are repeated one or more times. , At least three or more layers of metal foil may be included and at least two or more insulating layers may be included, and a multilayered printed circuit board may be configured by such a method.

Hereinafter, the functions and effects of the invention will be described in more detail through specific embodiments of the invention. However, these embodiments are only presented as examples of the invention, and the scope of the invention is not determined thereby.

Size 1280mm * 2100mm, thickness 0.215mm, consisting of a bismaleimide resin (Bismaleimide-Triazine) component, having a low dielectric constant characteristic (Low Dk), a B-Stage prepreg was prepared (manufacturer: LG Chem, Product name: LG-500LC(LD)).

As the metal foil for forming the conductive layer, a copper foil having a thickness of 2 um (not including the carrier 18 um) was prepared. (Manufacturer: Mitsui 2um Micro Thin Copper foil)

After laminating the prepreg on the copper foil, and then laminating the copper foil on it again, a laminating process was performed at a temperature of 220°C and a pressure of 5 MPa using a press machine equipped with a protective pad, thereby forming a thin metal laminate. Was prepared.

The protective pad used at this time is made of an aramid resin, has a size of 1280mm*2100mm and a thickness of 5.0mm; All edges of the protective pad were processed in a non-linear manner to form an isosceles triangular irregularity of 10 mm in width and height.

By repeating the above method, all 24 thin metal laminates were manufactured.

Comparative example

A laminating process was performed in the same manner as in the above embodiment, except that an existing protective pad, which was not separately processed, was used to prepare a thin metal laminate.

By repeating the above method, all 24 thin metal laminates were manufactured.

Pressure distribution measurement

In the laminating process, the pressure applied to the center portion and the edge of the prepreg was monitored, and the change in pressure according to the distance away from the center portion was measured, and shown in FIG. 5.

Referring to FIG. 5, in the case of the conventional manufacturing method in which the protective pad is not separately processed, the pressure difference applied to the prepreg does not appear large in the case of the central portion or the peripheral portion not far from the central portion, but the pressure at the edge portion You can clearly see that the change is happening so severely. However, in the case of the embodiment of the present application, although some pressure change appears toward the edge, it can be clearly confirmed that the difference is not large compared to the central part.

Thickness distribution measurement

In each of the thin metal laminates, the horizontal and vertical lengths were equally divided, 40 thickness measurement points were designated, the thickness of the corresponding portion was measured, and the measurement results are summarized in FIG. 6. (Examples and Comparative Examples, respectively, a total of 960 measurements)

In both Examples and Comparative Examples, the average thickness of the sample was 0.223 mm, in the case of the Example, the standard deviation was 0.00151324 mm, and in the case of the Comparative Example, the standard deviation was 0.00253194 mm.

Referring to FIG. 6, in the case of the present embodiment, it can be seen that the standard deviation value is about 0.6% of the average thickness, and it can be clearly confirmed that it has a very narrow distribution compared to the comparative example. In particular, in the case of the comparative example, it was confirmed that some values exceeded the upper limit of the standard due to the non-uniformity of the pressure in the laminating process. Appeared to be.

It can be seen that in the laminating process, due to the edge of the protective pad processed in the uneven shape, the pressure unevenness is effectively resolved, and accordingly, the variation in thickness is reduced.

7 is a photograph showing the surface conditions of the thin metal laminates manufactured according to Examples and Comparative Examples of the present invention.

Referring to FIG. 7, it can be clearly confirmed that a void phenomenon, in which voids between the copper foil and the prepreg are generated due to the non-uniform resin flow of the prepreg, appeared on the surface of the thin metal laminate manufactured according to the conventional method.

100: metal foil laminate
110: prepreg
120: metal foil
200: protective pad

Claims (9)

A) laminating one or more prepregs on a two-dimensional sheet-shaped metal foil;
B) laminating a metal foil on the prepreg to form a preliminary metal foil laminate; And
C) pressing the preliminary thin metal laminate to completely cure the prepreg;
C-1) In the pressing process, the preliminary metal foil laminate is subjected to a process of applying a protective pad in the shape of a two-dimensional sheet to both surfaces of the preliminary metal laminate and then pressing;
C-2) The protective pad has a non-linear edge;
Method of manufacturing a thin metal laminate.
The method of claim 1,
The prepreg is a method of manufacturing a thin metal laminate comprising an insulating resin and a reinforcing fiber impregnated in the insulating resin.
The method of claim 2,
The insulating resin includes a thermosetting resin, a method of manufacturing a thin metal laminate.
The method of claim 1,
The metal comprises at least one selected from the group consisting of gold, silver, platinum, aluminum, and copper, a method of manufacturing a thin metal laminate.
The method of claim 1,
The edge of the protective pad is processed in a non-linear shape of a curved uneven shape or a polygonal uneven shape, a method of manufacturing a thin metal laminate.
The method of claim 1,
The protective pad is in the form of a rectangular sheet; The edges are processed in a nonlinear state in the form of curved irregularities or polygonal irregularities,
The width and height of the curved irregularities or polygonal irregularities are each independently, 1/50 to 1/500 of the length of the side of the protective pad, a method of manufacturing a thin metal laminate.
The method of claim 1,
The pressing step is performed under a pressure condition of 1 to 10 MPa, a method of manufacturing a thin metal laminate.
The method of claim 1,
The thin metal laminate, wherein the standard deviation of the thickness of each portion is 0.7% or less with respect to the average thickness.
The method of claim 1,
A method of manufacturing a thin metal laminate by repeating steps A) and B) at least once to construct a multilayered printed circuit board.

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