KR102466205B1 - Printed circuit board and method for manufacturing the same - Google Patents

Abstract

A printed circuit board according to an aspect of the present invention includes a conductive core having a through hole; insulating layers formed on upper and lower surfaces of the conductive core and inner walls of the through hole; and a circuit formed on the insulating layer, wherein a thickness of a portion formed on upper and lower surfaces of the core in the insulating layer is greater than a thickness of a portion formed on an inner wall of the through hole.

Description

Printed circuit board and printed circuit board manufacturing method {PRINTED CIRCUIT BOARD AND METHOD FOR MANUFACTURING THE SAME}

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

With the development of technology, electronic devices are pursuing miniaturization and light weight, and accordingly, the number of electronic components mounted on a predetermined printed circuit board area is increasing, and the width of wiring and the distance between wiring are also decreasing.

As the number of electronic components increases, heat generation problems occur, and thus, development of printed circuit boards with improved heat dissipation characteristics continues.

Republic of Korea Patent Publication No. 1999-0037873 (2013.07.03)

An object of the present invention is to provide a printed circuit board with improved heat dissipation characteristics and low thermal expansion, and a method for manufacturing the same.

According to one aspect of the present invention, a conductive core having a through hole; insulating layers formed on upper and lower surfaces of the conductive core and inner walls of the through hole; and a circuit formed on the insulating layer, wherein in the insulating layer, a thickness of a portion formed on upper and lower surfaces of the core is greater than a thickness of a portion formed on an inner wall of the through hole.

According to another aspect of the present invention, forming a through hole in the conductive core; disposing a first insulating layer on an upper surface of the conductive core to cover an upper end of the through hole; introducing the first insulating layer into the through hole so that the first insulating layer is torn inside the through hole and attached to an inner wall of the through hole; and forming a second insulating layer on the lower surface of the conductive core.

1 is a view showing a printed circuit board according to an embodiment of the present invention.
Figure 2 is an enlarged view of a part of Figure 1;
3 to 12 are diagrams illustrating a method for manufacturing a printed circuit board according to an embodiment of the present invention.

Embodiments of a printed circuit board and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings, and in the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and Redundant descriptions will be omitted.

In addition, terms such as first and second used below are only identification symbols for distinguishing the same or corresponding components, and the same or corresponding components are not limited by terms such as first and second. not.

In addition, coupling does not mean only the case of direct physical contact between each component in the contact relationship between each component, but another configuration intervenes between each component so that the component is in the other configuration. It should be used as a concept that encompasses even the case of contact with each other.

printed circuit board

1 is a diagram showing a printed circuit board according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of FIG. 1 .

Referring to FIG. 1 , a printed circuit board according to an embodiment of the present invention includes a conductive core 110, an insulating layer 120, and a circuit 130, and in the insulating layer 120, the core 110 ) is characterized in that the thickness of the portion formed on the upper and lower surfaces of the through hole 111 is greater than the thickness of the portion formed on the inner wall of the through hole 111.

The conductive core 110 is a core made of a material having thermal and electrical conductivity. For example, the conductive core 110 may be a metal material or a resin material containing non-metallic carbon. The conductive core 110 may have high thermal conductivity and low thermal expansion characteristics.

When the conductive core 110 is made of a metal material, since the metal has high thermal conductivity and high rigidity, heat dissipation characteristics of the printed circuit board may be improved and rigidity may be increased. If the rigidity of the printed circuit board is increased, warpage control of the printed circuit board becomes easy.

As a metal used for the conductive core 110, copper (Cu), aluminum (Al), magnesium (Mg), titanium (Ti), hafnium (Hf), zinc (Zn), tungsten (W), molybdenum (Mo) etc. may be included. In addition, an alloy such as Invar or Kovar may be used as the metal layer 120 .

Meanwhile, as shown in FIG. 1 , two types of metal may be used for the conductive core 110 . In this case, the conductive core 110 may be formed by forming a second metal on both sides of the first metal. The first metal and the second metal may be manufactured in a sheet form and laminated to each other.

For example, the first metal may be enva and the second metal may be copper. That is, the conductive core 110 may have a copper layer formed on both sides of the invar layer. Here, copper particularly improves the heat dissipation characteristics of the printed circuit board, and invar particularly increases the rigidity of the printed circuit board. Invar is effective in improving the warpage problem of printed circuit boards under high temperature conditions because the change in physical properties is insignificant at temperatures below 200 ° C.

The conductive core 110 may have a thickness sufficient to improve the heat dissipation effect and the warpage improvement effect and at the same time not make the entire printed circuit board thicker than necessary, and specifically may have a thickness of 20 μm to 100 μm.

Meanwhile, when the conductive core 110 is a resin material containing carbon, the carbon may exist in the form of fibers. That is, the conductive core 110 may have a resin material impregnated with carbon fiber.

The resin material may include a thermosetting resin such as an epoxy resin or a thermoplastic resin such as polyimide (PI).

Epoxy resins include, for example, naphthalene-based epoxy resins, bisphenol A-type epoxy resins, bisphenol-F-type epoxy resins, novolac-type epoxy resins, cresol novolak-type epoxy resins, rubber-modified epoxy resins, and cyclic aliphatic epoxy resins. It may be a resin, a silicone-based epoxy resin, a nitrogen-based epoxy resin, a phosphorus-based epoxy resin, and the like, but is not limited thereto.

In addition, polyimide is a material with high ductility and is easy to handle.

The carbon fibers may be formed over the entire resin material or intensively formed in the center of the resin material.

Meanwhile, carbon is not limited to a fiber form and may be distributed in a resin material in a filler form.

A through hole 111 may be provided in the conductive core 110 . The through hole 111 penetrates all from the upper surface to the lower surface of the conductive core 110 . The cross-sectional area of the through hole 111 may decrease from the upper surface to the center and increase from the center to the lower surface. However, the cross-sectional area of the through hole 111 is not limited to the above-described shape, and the cross-sectional area of the through hole 111 may be constant from the upper surface to the lower surface of the conductive core 110 .

Here, in relation to the top and bottom surfaces, the concept of top and bottom is introduced to distinguish the two surfaces, and does not mean an absolute top and bottom positional relationship. Therefore, the upper surface and the lower surface are to be understood as one surface and the other surface facing each other. The same applies to the upper and lower surfaces described below.

The through hole 111 may be formed by a method such as laser processing, mechanical drilling, or etching. In particular, when the conductive core 110 is made of a metal material, the through hole 111 may be formed by an etching method, and when the conductive core 110 is a resin material containing carbon fiber, the through hole 111 may be formed by laser processing. ) can be formed.

The through hole 111 may be formed in plurality. A pitch between the plurality of through holes 111 may be 150 um or less. Here, 'pitch' is a distance between centers, and thus, a distance between centers of the plurality of through holes 111 may be 150 μm or less.

The insulating layer 120 is formed on the upper and lower surfaces of the conductive core 110 and the inner wall of the through hole 111 . That is, all surfaces of the conductive core 110 except for the side surface are covered by the insulating layer 120 and are not exposed.

When the via 140 and the circuit 130, which will be described later, are formed in the conductive core 110, since the via 140 and the circuit 130 are conductive, the core 110 and the via 140 or the circuit 130 need to be insulated from each other. It is the insulating layer 120 that performs such a function.

The insulating layer 120 may be made of a thermoplastic resin. In particular, the insulating layer 120 may be a resin having a component mounting temperature, for example, a melting point of 260 degrees Celsius or higher. In addition, the insulating layer 120 is preferably a resin having heat resistance and low dielectric constant.

For example, the insulating layer 120 may be formed of at least one selected from polyether ether ketone (PEEK), polycyclohezylene dimethylene terephthalate (PCT), polyphenylene sulfide (PPS), and liquid crystal polymer (LCP).

The insulating layer 120 may have a constant thickness on the upper and lower surfaces of the conductive core 110 , and a portion formed on an inner wall of the through hole 111 may be thinner than a portion formed on the upper and lower surfaces of the conductive core 110 .

In addition, in the portion formed on the inner wall of the through hole 111, the thickness may decrease toward the inside from the end of the through hole 111. In this case, the thickness of the portion of the insulating layer 120 located at the center of the through hole 111 is the thinnest.

In FIG. 2 , the thickness of the insulating layer 120 is shown. Referring to FIG. 2 , the thickness of the portion L1 formed on the upper and lower surfaces of the conductive core 110 is a, and the thickness of the portion L2 formed on the inner wall of the through hole 111 is b and c. Thickness a is greater than thicknesses b and c.

In addition, among the portions L2 formed on the inner wall of the through hole 111, the thickness of those located at the upper and lower ends of the through hole 111 is b, and the thickness of the portion L2 located in the center of the through hole 111 is c. Thickness b is greater than thickness c.

However, the relationship between the thickness b and the thickness c is not limited to that shown in FIG. 2 , and the thickness b and the thickness c may be the same.

The circuit 130 may be formed of a metal having excellent electrical properties, and the metal constituting the circuit 130 includes copper (Cu), silver (Ag), palladium (Pd), aluminum (Al), and nickel (Ni). , titanium (Ti), gold (Au), platinum (Pt), and the like may be included.

The circuit 130 may be formed by a method such as additive, subtractive, semi-additive, tenting, modified semi-additive process (MSAP), etc. method is not limited.

The circuit 130 may be formed both above and below the core 110 . In addition, a part of the circuit 130 may be located above and below the through hole 111 .

The printed circuit board according to an embodiment of the present invention may further include vias 140 .

The via 140 electrically connects each of the circuits 130 formed on the top and bottom of the core 110 .

The via 140 is formed inside the through hole 111 and contacts the circuit 130 located above and below the through hole 111 . In this case, the via 140 may be formed to fill the entire through hole 111 .

The via 140 may be formed of the same metal as the circuit 130 . Also, the via 140 may be integrated with the circuit 130 . Even if the via 140 is made of a conductive material, the via 140 and the conductive core 110 may be insulated from each other by the insulating layer 120 formed on the inner wall of the through hole 111 .

Printed circuit board manufacturing method

3 to 12 are diagrams illustrating a method of manufacturing a printed circuit board according to an embodiment of the present invention.

3 to 12, a method of manufacturing a printed circuit board according to an embodiment of the present invention includes forming a through hole 111 in a conductive core 110, on an upper surface of the conductive core 110, Disposing a first insulating layer 121 to cover the top of the through hole 111, such that the first insulating layer 121 is torn inside the through hole 111 and adhered to the inner wall of the through hole 111 , introducing the first insulating layer 121 into the through hole 111 and forming a second insulating layer 122 on the lower surface of the conductive core 110 .

In the step of forming the second insulating layer 122 on the lower surface of the conductive core 110, the second insulating layer 122 is formed on the lower surface of the conductive core 110 to cover the lower end of the through hole 111. and disposing the second insulating layer 122 into the through hole 111 so that the second insulating layer 122 is torn inside the through hole 111 and formed on the inner wall of the through hole 111. It may include an inlet step.

In the printed circuit board manufacturing method according to an embodiment of the present invention, before the step of introducing the first insulating layer 121 into the through hole 111, applying heat to the first insulating layer 121 The method may further include a step of applying heat to the second insulating layer 122 prior to introducing the second insulating layer 122 into the through hole 111. .

In the method of manufacturing a printed circuit board according to an embodiment of the present invention, forming a via 140 in the through hole 111 and on the first insulating layer 121 and the second insulating layer 122 A step of forming the circuit 130 may be further included.

Referring to FIG. 3 , a through hole 111 is formed in the conductive core 110 . The through hole 111 may be formed by a method such as laser processing, mechanical drilling, or etching. In particular, when the conductive core 110 is made of a metal material, the through hole 111 may be formed by an etching method, and when the conductive core 110 is a resin material containing carbon fiber, the through hole 111 may be formed by laser processing. ) can be formed.

The through hole 111 may be formed to pass through all of the conductive core 110 from the upper surface to the lower surface. The cross-sectional area of the through hole 111 may decrease from the upper surface to the center and increase from the center to the lower surface. In this case, the through hole 111 may have an hourglass shape.

Referring to FIG. 4 , a first insulating layer 121 is disposed on the upper surface of the conductive core 110 . The first insulating layer 121 adheres to the upper surface of the conductive core 110 . The first insulating layer 121 covers the top of the through hole 111 of the conductive core 110 . That is, the upper end of the through hole 111 is not exposed by the first insulating layer 121 .

Referring to FIG. 5 , heat is applied to the first insulating layer 121 . When the first insulating layer 121 is thermoplastic, the first insulating layer 121 may be softened by receiving heat. The softened first insulating layer 121 may be deformed. The temperature of the heat applied to the first insulating layer 121 may be higher than the softening point and lower than the melting point of the first insulating layer 121 . The source of applied heat may be hot air.

Referring to FIG. 6 , the first insulating layer 121 flows into the through hole 111 . The first insulating layer 121 of the portion covering the top of the through hole 111 is inflated (inflation) toward the inside of the through hole 111 .

Here, pressure may be applied to the first insulating layer 121 toward the through hole 111 .

Specifically, pressure may be applied from the outside of the first insulating layer 121 to the inside of the through hole 111 with respect to the first insulating layer 121 . For example, wind may act on the first insulating layer 121 from outside the first insulating layer 121 . In this case, the first insulating layer 121 may expand like bubble gum and flow into the through hole 111 .

Alternatively, the first insulating layer 121 may flow into the through hole 111 while the inside of the through hole 111 is depressurized.

In either case, the first insulating layer 121 may be swollen, expanded, or stretched to flow into the through hole 111 .

Referring to FIG. 7 , a portion of the first insulating layer 121 introduced into the through hole 111 is torn and adhered to the inner wall of the through hole 111 . That is, the first insulating layer 121 is attached to the inner wall of the through hole 111 .

Specifically, when a pressure higher than the elastic and plastic regions is continuously applied to the first insulating layer 121 , holes (holes) are formed in the first insulating layer 121 introduced into the through hole 111 . As the first insulating layer 121 expands, the hole becomes larger, and when the hole becomes larger than the size of the through hole 111 , the first insulating layer 121 may be attached to the inner wall of the through hole 111 .

Meanwhile, the thickness of the first insulating layer 121 introduced into the through hole 111 may be thinner than the original thickness. Therefore, in the first insulating layer 121 , the thickness of the portion introduced into the through hole 111 may be smaller than the thickness of the portion located on the upper surface of the conductive core 110 .

Referring to FIG. 8 , a second insulating layer 122 is disposed on the lower surface of the conductive core 110 . The second insulating layer 122 adheres to the lower surface of the conductive core 110 . The second insulating layer 122 covers the lower end of the through hole 111 of the conductive core 110 . That is, the lower end of the through hole 111 is not exposed by the second insulating layer 122 .

Referring to FIG. 9 , heat is applied to the second insulating layer 122 . When the second insulating layer 122 is thermoplastic, the second insulating layer 122 may be softened by receiving heat. The softened second insulating layer 122 may be deformed. The temperature of the heat applied to the second insulating layer 122 may be higher than the softening point and lower than the melting point of the second insulating layer 122 .

Referring to FIG. 10 , the second insulating layer 122 flows into the through hole 111 . The second insulating layer 122 of the portion covering the top of the through hole 111 is inflated (inflation) toward the inside of the through hole 111 .

Here, pressure may be applied to the second insulating layer 122 toward the through hole 111 .

Specifically, pressure may be applied from the outside of the second insulating layer 122 to the inside of the through hole 111 with respect to the second insulating layer 122 . Alternatively, the second insulating layer 122 may flow into the through hole 111 while the inside of the through hole 111 is depressurized.

In either case, the second insulating layer 122 may be swollen, expanded, or stretched to flow into the through hole 111 .

Referring to FIG. 11 , a portion of the second insulating layer 122 introduced into the through hole 111 is torn and adhered to the inner wall of the through hole 111 . That is, the second insulating layer 122 is attached to the inner wall of the through hole 111 .

Specifically, when a pressure higher than the elastic and plastic regions is continuously applied to the second insulating layer 122 , a hole (hole) is formed in the second insulating layer 122 introduced into the through hole 111 . As the second insulating layer 122 expands, the hole becomes larger, and when the hole becomes larger than the size of the through hole 111 , the second insulating layer 122 may be attached to the inner wall of the through hole 111 .

Meanwhile, the thickness of the second insulating layer 122 introduced into the through hole 111 may be thinner than the original thickness. Therefore, in the second insulating layer 122 , the thickness of the portion introduced into the through hole 111 may be smaller than the thickness of the portion located on the lower surface of the conductive core 110 .

In the above process, the first insulating layer 121 may cover the entire inner wall of the through hole 111, but may cover a part of the inner wall of the through hole 111. When the first insulating layer 121 covers a portion of the inner wall of the through hole 111 , the second insulating layer 122 may cover the rest of the inner wall of the through hole 111 . Also, in this case, the first insulating layer 121 and the second insulating layer 122 may overlap each other.

In particular, the first insulating layer 121 and the second insulating layer 122 may overlap each other at the center of the inner wall of the through hole 111 . Both the first insulating layer 121 and the second insulating layer 122 are thermoplastic, and in particular, when the two insulating layers 120 are made of the same resin material, the first insulating layer 121 and the second insulating layer 122 ), the overlapped parts can become integral, and the boundary between them can disappear. However, in some cases, a boundary may be observed in the overlapping portion of the first insulating layer 121 and the second insulating layer 122 .

Meanwhile, the above process may be repeated. That is, the inflation process of the first insulating layer 121 and the inflation process of the second insulating layer 122 may be sequentially repeated.

When the insulating layer 120 is formed through this process, the thickness of the insulating layer 120 is reduced, and thus the pitch between the through holes 111 can be reduced, so that a fine pattern can be implemented.

In the method of manufacturing a printed circuit board according to an embodiment of the present invention, forming a via 140 in the through hole 111 and on the first insulating layer 121 and the second insulating layer 122 A step of forming the circuit 130 may be further included.

Referring to FIG. 12 , a via 140 is formed in the through hole 111 and a circuit 130 is formed on the insulating layer 120 .

The via 140 may be formed by filling the through hole 111 with conductive paste or plating the inside of the through hole 111 .

In particular, when the inside of the through hole 111 is plated, an electroless plating layer using a palladium catalyst is first formed inside the through hole 111, and an electroplating layer is formed on the layer to fill the through hole 111, thereby forming vias ( 140) may be formed.

The circuit 130 may be formed by a method such as additive, subtractive, semi-additive, tenting, modified semi-additive process (MSAP), or the like.

In particular, when the circuit 130 is formed by an additive method, a semi-additive method, or the like, the electroless plating layer may be formed not only inside the through hole 111 but also on the surface of the insulating layer 120 . The circuit 130 may be completed by selectively forming an opening in the dry film through a photo lithography process and growing an electrolytic plating layer from the seed layer for the opening.

The dry film is peeled off, and an unnecessary part of the seed layer, that is, a seed layer formed in a portion other than the circuit 130 is removed by etching.

Although one embodiment of the present invention has been described above, those skilled in the art can add, change, delete, or add components within the scope not departing from the spirit of the present invention described in the claims. The present invention can be variously modified and changed by the like, and this will also be said to be included within the scope of the present invention.

110: conductive core
111: through hole
120: insulating layer
121: first insulating layer
122: second insulating layer
130: circuit
140 via

Claims (17)

a conductive core having a through hole;
insulating layers formed on upper and lower surfaces of the conductive core and inner walls of the through hole; and
a circuit formed on the insulating layer;
In the insulating layer, the thickness of the portion formed on the upper and lower surfaces of the core is greater than the thickness of the portion formed on the inner wall of the through hole,
The thickness of the insulating layer formed inside the through hole, the thickness at the top and bottom of the through hole is greater than the thickness at the center of the through hole,
printed circuit board.
According to claim 1,
The insulating layer is a printed circuit board made of a thermoplastic resin.
According to claim 2,
The insulating layer is a printed circuit board made of at least one selected from polyether ether ketone (PEEK), polycyclohezylene dimethylene terephthalate (PCT), polyphenylene sulfide (PPS), and liquid crystal polymer (LCP).
According to claim 1,
A printed circuit board in which the core is a resin material containing carbon fiber.
According to claim 1,
The core is a printed circuit board made of a metal material.
According to claim 1,
The printed circuit board of claim 1 , wherein a thickness of the insulating layer formed inside the through hole decreases as it goes inward from an end of the through hole.
According to claim 1,
The printed circuit board further comprising a via formed inside the through hole.
According to claim 1,
The printed circuit board of claim 1 , wherein a plurality of through holes are formed, and a pitch between the plurality of through holes is 150 um or less.
Forming a through hole in the conductive core;
disposing a first insulating layer on an upper surface of the conductive core to cover an upper end of the through hole;
introducing the first insulating layer into the through hole so that the first insulating layer is torn inside the through hole and attached to an inner wall of the through hole; and
A method of manufacturing a printed circuit board comprising forming a second insulating layer on a lower surface of the conductive core.
According to claim 9,
Forming a second insulating layer on the lower surface of the conductive core,
disposing a second insulating layer on a lower surface of the conductive core to cover a lower end of the through hole; and
and introducing the second insulating layer into the through hole so that the second insulating layer is torn inside the through hole and formed on an inner wall of the through hole.
According to claim 9,
Prior to introducing the first insulating layer into the through hole,
The method of manufacturing a printed circuit board further comprising the step of applying heat to the first insulating layer.
According to claim 11,
Wherein the first insulating layer and the second insulating layer are made of a thermoplastic resin.
According to claim 9,
In the step of introducing the first insulating layer into the through hole,
A method of manufacturing a printed circuit board in which pressure is applied to the first insulating layer toward the through hole.
According to claim 9,
In the step of introducing the first insulating layer into the through hole,
A method of manufacturing a printed circuit board in which a portion of the first insulating layer introduced into the through hole is thinner than a portion formed on the upper surface of the conductive core.
According to claim 10,
In the step of introducing the first insulating layer into the through hole,
The first insulating layer covers a portion of an inner wall of the through hole;
In the step of introducing the second insulating layer into the through hole,
The second insulating layer covers the rest of the inner wall of the through hole.
According to claim 15,
The second insulating layer and the first insulating layer partially overlap inside the through hole.
According to claim 9,
forming a via in the through hole; and
The method of manufacturing a printed circuit board further comprising forming a circuit on the first insulating layer and the second insulating layer.

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