KR102548609B1 - Printed circuit board - Google Patents

Abstract

A printed circuit board according to an embodiment of the present invention includes a first metal layer, a resin composition disposed on the first metal layer, and including an agglomerate in which resin and plate-shaped boron nitride are aggregated, and a plurality of holes ( A hole) is formed on the insulating layer, and a second metal layer is disposed on the insulating layer, and the hole is filled with a material having higher thermal conductivity than the resin composition.

Description

Printed circuit board {PRINTED CIRCUIT BOARD}

The present invention relates to a printed circuit board.

A printed circuit board (PCB) includes a circuit pattern layer formed on an insulating layer, and various electronic components may be mounted on the printed circuit board. The electronic component mounted on the printed circuit board may be, for example, a heating element. The heat emitted by the heating element may degrade the performance of the printed circuit board. In particular, with the high integration and high capacity of electronic components, interest in heat dissipation of printed circuit boards is growing.

On the other hand, the printed circuit board can be divided into a single-sided PCB in which the circuit pattern layer is wired on one side of the board, a double-sided PCB in which the circuit pattern layer is wired on both sides of the board, and a multi-layer PCB in which the circuit pattern layer is wired in multiple layers. . As the complexity of circuits increases and the demand for high-density and miniaturized circuits increases, double-sided PCBs or multi-layer PCBs are widely used.

In general, a ceramic substrate having high thermal conductivity can be used as a printed circuit board, but the ceramic substrate is fragile and difficult to process, and it is impossible to realize it as a multi-layer PCB.

In addition, attempts have been made to apply FR-4 containing resin and glass fibers to a multilayer PCB, but since FR-4 has low thermal conductivity, there is a problem in that it does not effectively respond to heat emitted by the heating element.

A technical problem to be achieved by the present invention is to provide a printed circuit board having excellent heat dissipation performance and easy processing.

A printed circuit board according to an embodiment of the present invention includes a first metal layer, a resin composition disposed on the first metal layer, and including an agglomerate in which resin and plate-shaped boron nitride are aggregated, and a plurality of holes ( A hole) is formed on the insulating layer, and a second metal layer is disposed on the insulating layer, and the hole is filled with a material having higher thermal conductivity than the resin composition.

The diameter of the hole may be 100 μm to 500 μm.

The hole may be filled with at least one material selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), carbon nanotube (CNT), graphene, and graphite. can

Walls of at least some of the plurality of holes may be coated with metal and filled with the material, and other portions may have walls not coated with metal and filled with the material.

The first metal layer and the second metal layer may cover both ends of the hole.

The resin composition may further include at least one of aluminum oxide and aluminum nitride.

At least one of the first metal layer and the second metal layer is divided into a first electrode region and a second electrode region that are insulated from each other, at least some of the plurality of holes are formed in the first electrode region, and the other part is formed in the first electrode region. It may be formed in the second electrode region.

A printed circuit board according to another embodiment of the present invention includes a plurality of sequentially disposed metal layers, and a resin composition formed between the plurality of metal layers and including an agglomerate of resin and plate-shaped boron nitride. It includes a plurality of insulating layers, and a plurality of holes are formed through at least a portion of the plurality of metal layers and the plurality of insulating layers, and the holes are filled with a material having higher thermal conductivity than the resin composition.

According to an embodiment of the present invention, a printed circuit board having high heat dissipation performance and excellent processability can be obtained. In particular, since a printed circuit board that can be implemented in multiple layers can be obtained, highly integrated and high-capacity electronic components can be obtained.

1 is a cross-sectional view of a printed circuit board according to an embodiment of the present invention.
2 is a top view of a printed circuit board according to an embodiment of the present invention.
3 to 4 are photographs showing a cross section of an insulating layer made of a resin composition according to an embodiment of the present invention.
5 is a cross-sectional view of a hole formed in a printed circuit board according to an embodiment of the present invention.
6 is a cross-sectional view of a hole formed in a printed circuit board according to another embodiment of the present invention.
7 shows electronic components mounted on a printed circuit board according to an embodiment of the present invention.
8 shows a method of manufacturing a printed circuit board according to an embodiment of the present invention.
9 is a cross-sectional view of a 4-layer printed circuit board according to an embodiment of the present invention.

Since the present invention can make various changes and have various embodiments, specific embodiments are illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second and first may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be termed a first element, and similarly, a first element may be termed a second element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, they should not be interpreted in an ideal or excessively formal meaning. don't

When a part such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between.

Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings, but the same or corresponding components regardless of reference numerals are given the same reference numerals, and overlapping descriptions thereof will be omitted.

1 is a cross-sectional view of a printed circuit board according to an embodiment of the present invention, and FIG. 2 is a top view of the printed circuit board according to an embodiment of the present invention.

Referring to FIGS. 1 and 2 , the printed circuit board 100 includes a first metal layer 110 , an insulating layer 120 disposed on the first metal layer 110 , and a second insulating layer disposed on the insulating layer 120 . A metal layer 130 is included. At this time, the insulating layer 120 is made of a resin composition including an agglomerate 122 in which resin and plate-shaped boron nitride are aggregated, and a plurality of holes 140 are formed in the insulating layer 120 . The plurality of holes 140 are filled with a material having higher thermal conductivity than the resin composition. As such, when the thermal conductivity of the material filling the hole 140 is greater than the thermal conductivity of the resin composition, heat can be efficiently discharged through the hole 140 .

At this time, the diameter D of the hole 140 may be 100 μm to 500 μm, preferably 200 μm to 400 μm, and more preferably 250 μm to 350 μm. When the diameter D of the hole 140 satisfies this numerical range, it is easy to fill the hole 140 with a material having high thermal conductivity, and thus the heat dissipation performance of the printed circuit board 100 can be improved.

Here, the material with high thermal conductivity filled in the hole 140 is, for example, copper (Cu), aluminum (Al), silver (Ag), carbon nanotube (CNT), graphene And it may include at least one material selected from the group consisting of graphite. At this time, these materials may be filled in powder or paste form. Table 1 shows the thermal conductivities of materials that may be filled in the hole 140 .

Pure material Thermal conductivity(W/mK) Cu 400 Al 238 Ag 430 Carbon (ex. CNT, graphene, graphite) >335

In general, the thermal conductivity of a resin composition including an agglomerate of resin and plate-shaped boron nitride is 2 to 10 W/mK. However, if a material having high thermal conductivity is filled in the hole 140 formed in the insulating layer 120 made of a resin composition, the thermal conductivity of the insulating layer 120 may be improved as a whole.

3 to 4 are photographs showing a cross section of an insulating layer made of a resin composition according to an embodiment of the present invention.

Referring to FIGS. 3 and 4 , the insulating layer 120 includes a resin composition including an agglomerate of resin and plate-shaped boron nitride. At this time, the plate-shaped boron nitride aggregate may be included in 10 to 90 wt%, preferably 20 to 70 wt%, more preferably 30 to 50 wt%, and more preferably 35 to 45 wt% of the resin composition. When the plate-shaped boron nitride agglomerate is included in the resin composition in this numerical range, the strength and hardness of the insulating layer 120 may be at a level where it is easy to form a hole using drilling. Here, the plate-shaped boron nitride agglomerate may have isotropic thermal conduction characteristics having uniform thermal conduction performance in all directions, and may also improve dispersibility and insulation performance. In addition, the plate-shaped boron nitride aggregate has a diameter of about 100 μm to 300 μm and a density of about 2.2 g/cm ³ to 2.4 g/cm ³ . The density of the insulating layer made of the resin composition including the agglomerates in which the plate-shaped boron nitride is agglomerated may be about 2.4 to 2.5 g/cm ³ .

As described above, since the density of the insulating layer according to the embodiment of the present invention is lower than the density of 3.7 to 3.9 g/cm ³ of a ceramic substrate such as aluminum oxide, it is easy to process the hole 140 . That is, in the case of a ceramic substrate, only hole processing using a laser is possible, and the maximum diameter of a hole that can be obtained is about 90 μm. In contrast, in the case of the insulating layer 120 according to the embodiment of the present invention, not only laser but also hole processing using drilling is possible, and hole processing with a diameter of 100 μm or more is possible. As the diameter of the hole 140 increases, the process of filling the hole with a material having high thermal conductivity becomes easier, and since the area of the region with high thermal conductivity in the insulating layer 120 increases, the thermal conductivity of the entire insulating layer 120 increases. level can be effectively increased.

Here, the resin composition may further include at least one of aluminum oxide (Al ₂ O ₃ ) and aluminum nitride (AlN). Accordingly, the thermal conductivity of the resin composition itself can be further improved. At this time, the resin included in the resin composition may be an epoxy compound. Epoxy compounds are excellent in heat resistance and dispersibility. The epoxy resin may include at least one of a crystalline epoxy compound and an amorphous epoxy compound. The crystalline epoxy compound may include a mesogenic structure. Here, mesogen is a basic unit of liquid crystal and includes a rigid structure. The mesogen may include, for example, a rigid structure such as the following (a) to (e).

(a)

(b)

(c)

(d)

(e)

The amorphous epoxy compound may be a normal amorphous epoxy compound having two or more epoxy groups in the molecule, and examples thereof include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, cyclo type epoxy compounds, novolac type epoxy compounds, and aliphatic epoxy compounds. It may be an epoxy compound or the like.

Meanwhile, according to an embodiment of the present invention, the first metal layer 110 and the second metal layer 130 may cover both ends of the plurality of holes 140 filled with a material having high thermal conductivity. Accordingly, as shown in FIG. 2, the hole 140 is not exposed on the surface of the printed circuit board 100, and the phenomenon in which burrs are formed around the hole 140 after machining the hole 140 is minimized. can do. In addition, since an electronic component (eg, a chip) can be mounted on the hole 140, the degree of freedom of the hole 140 formation position can be increased.

In addition, according to an embodiment of the present invention, as shown in FIG. 2 , at least one of the first metal layer 110 and the second metal layer 130 is insulated from each other, the first electrode region 132 and the second electrode region (134). The first electrode region 132 may be one of a (+) electrode and a (-) electrode, and the second electrode region 134 may be the other one. In this case, at least some of the plurality of holes 140 may be formed in the first electrode region 132 and the remaining portions may be formed in the second electrode region 134 . In this way, when the hole 140 is formed in each of the first electrode region 132 and the second electrode region 134, the hole 140 can serve not only for heat conduction but also for conduction.

5 is a cross-sectional view of a hole formed in a printed circuit board according to one embodiment of the present invention, and FIG. 6 is a cross-sectional view of a hole formed in a printed circuit board according to another embodiment of the present invention.

Referring to FIG. 5 , the wall surface of the hole 140-1 may be coated with a metal 142, and the inside of the hole 140-1 may be filled with a material having higher thermal conductivity than the resin composition.

Referring to FIG. 6 , the wall surface of the hole 140-2 may not be coated with metal, and the inside of the hole 140-2 may be filled with a material having higher thermal conductivity than the resin composition.

The hole 140-1 shown in FIG. 5 may serve as conduction as well as the role of heat conduction, and the hole 140-2 shown in FIG. 6 may serve as conduction of heat. Accordingly, the hole 140-1 of FIG. 5 and the hole 140-2 of FIG. 6 may be disposed in different regions. For example, as shown in FIG. 7 , when an electronic component (eg, a light emitting diode (LED) chip) is mounted on a printed circuit board according to an embodiment of the present invention, the hole 140-1 according to FIG. 5 is disposed at the edge of the region where the electronic component 700 is set to be mounted, and the hole 140-2 according to FIG. 6 may be disposed below the region where the electronic component 700 is set to be mounted. Accordingly, the hole 140-1 shown in FIG. 5 performs the role of heat conduction and conduction, and the hole 140-2 shown in FIG. 6 can efficiently perform the role of heat conduction at a point where the amount of heat is high. In order to improve heat conduction performance at a point with a high calorific value, the diameter of the hole 140-2 shown in FIG. 6 may be larger than that of the hole 140-2 shown in FIG. 5 .

8 shows a method of manufacturing a printed circuit board according to an embodiment of the present invention.

Referring to FIG. 8(a), a metal layer (Cu layer), an insulating layer 120, and a second metal layer (Cu layer) are sequentially disposed. Here, the metal layer disposed on both sides of the insulating layer 120 is illustrated as a Cu layer, but is not limited thereto, and may include copper, aluminum, nickel, gold, platinum, and an alloy selected therefrom. In addition, the insulating layer 120 may include a resin composition including an agglomerate in which a resin and plate-shaped boron nitride are aggregated. The resin composition may further contain aluminum oxide and aluminum nitride.

Referring to FIG. 8( b ), processing of a hole 140 is performed. Hole 140 may be processed using a laser or drilling. Since the strength and hardness of the insulating layer 120 according to the embodiment of the present invention are weaker than those of the ceramic substrate, drilling is possible.

Next, referring to FIG. 8(c), the inside of the hole 140 is made of a material having higher thermal conductivity than the resin composition, for example, copper (Cu), aluminum (Al), silver (Ag), carbon nanotubes ( It is filled with at least one material selected from the group consisting of Carbon Nono Tube (CNT), graphene, and graphite. At this time, the material filling the inside of the hole 140 may be in the form of powder or paste.

Finally, referring to FIG. 8(d), the surfaces of both metal layers are coated with the first metal layer 110 and the second metal layer 130. Accordingly, both ends of the hole 140 may be covered with the first metal layer 110 and the second metal layer 130. Here, the first metal layer 110 and the second metal layer 130 are copper, aluminum, nickel, or gold. , platinum and alloys selected therefrom.

Meanwhile, a printed circuit board according to an embodiment of the present invention may be implemented in multiple layers.

9 is a cross-sectional view of a 4-layer printed circuit board according to an embodiment of the present invention. Redundant descriptions of the same contents as those of FIGS. 1 to 8 are omitted.

Referring to FIG. 9 , a four-layer printed circuit board 900 includes a plurality of metal layers 910 sequentially disposed, and a plurality of insulating layers 920 formed between the plurality of metal layers 910 . Here, the plurality of metal layers 910 may include copper, aluminum, nickel, gold, platinum, and an alloy selected therefrom. Also, the plurality of insulating layers 920 insulate the plurality of metal layers 910 . According to such a multilayer printed circuit board, high integration and high capacity are possible.

Here, the plurality of insulating layers 920 include a resin composition including an agglomerate of resin and plate-shaped boron nitride, and penetrate at least a portion of the plurality of metal layers 910 and the plurality of insulating layers 920. A hole 940 is formed, and the hole 940 may be filled with a material having higher thermal conductivity than the resin composition.

In this case, the uppermost metal layer and the lowermost metal layer may cover both ends of the hole 940 .

As described above, according to an embodiment of the present invention, since hole processing is easy even in a multilayer printed circuit board, it is possible to obtain a printed circuit board having high heat dissipation performance as well as high integration and high capacity.

Here, a 4-layer printed circuit board has been described as an example, but is not limited thereto. Embodiments of the present invention may be applied not only to a 4-layer printed circuit board, but also to a 10-layer printed circuit board and a 12-layer printed circuit board.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

Claims (11)

a first metal layer;
An insulating layer disposed on the first metal layer, including a resin composition including an agglomerate of resin and plate-shaped boron nitride, and having a plurality of holes formed therein; and
A second metal layer disposed on the insulating layer,
The hole is filled with a material having higher thermal conductivity than the resin composition,
The plate-shaped boron nitride aggregate is included in 35wt% to 45wt% of the resin composition,
Some of the plurality of holes are first holes whose walls are coated with metal and filled with the material, and some of the holes are second holes whose walls are not coated with metal and whose insides are filled with the material;
A diameter of the second hole is greater than a diameter of the first hole, and the second hole is disposed in an area set to mount an electronic component. According to claim 1,
The diameter of the hole is 100㎛ to 500㎛ printed circuit board. According to claim 2,
The hole is filled with at least one material selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), carbon nanotube (CNT), graphene, and graphite. is a printed circuit board. delete According to claim 1,
The first metal layer and the second metal layer cover both ends of the hole. According to claim 1,
The resin composition further comprises at least one of aluminum oxide and aluminum nitride printed circuit board. According to claim 1,
At least one of the first metal layer and the second metal layer is divided into a first electrode region and a second electrode region insulated from each other,
At least a portion of the plurality of holes is formed in the first electrode area, and the remaining portion is formed in the second electrode area. A plurality of metal layers sequentially disposed, and
It is formed between the plurality of metal layers and includes a plurality of insulating layers including a resin composition including an agglomerate of resin and plate-shaped boron nitride,
A plurality of holes are formed through at least a portion of the plurality of metal layers and the plurality of insulating layers, and the holes are filled with a material having higher thermal conductivity than the resin composition,
The plate-shaped boron nitride aggregate is included in 35wt% to 45wt% of the resin composition,
Some of the plurality of holes are first holes whose walls are coated with metal and filled with the material, and some of the holes are second holes whose walls are not coated with metal and whose insides are filled with the material,
A diameter of the second hole is greater than a diameter of the first hole, and the second hole is disposed in an area set to mount an electronic component. According to claim 8,
The diameter of the hole is 100㎛ to 500㎛ printed circuit board. According to claim 9,
The hole is filled with at least one material selected from the group consisting of copper (Cu), aluminum (Al), silver (Ag), carbon nanotube (CNT), graphene, and graphite. is a printed circuit board. According to claim 8,
An uppermost metal layer and a lowermost metal layer among the plurality of metal layers cover both ends of at least some of the plurality of holes.

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