KR101154605B1 - The printed circuit board and the method for manufacturing the same - Google Patents

Abstract

The present invention relates to a printed circuit board, and a method of manufacturing a printed circuit board includes: forming a base circuit board having an internal circuit layer outside the cavity, the cavity circuit pattern in the cavity area above and below the substrate, on the cavity circuit pattern; Forming a cavity separation layer, forming at least one insulating layer and a circuit layer on the base circuit board, controlling the focal length of a laser to reach the surface of the substrate, and controlling the insulating layer on the etch stop pattern; Cutting the cavity separation layer, and separating the cavity separation layer to remove the cut insulation layer to form the cavity. Therefore, by forming the cavity separation layer on the cavity circuit pattern and cutting the cavity separation layer using a laser, the insulation layer can be separated to easily remove the insulation layer in the cavity.

Description

[0001] The present invention relates to a printed circuit board and a method of manufacturing the same,

The present invention relates to a printed circuit board and a method of manufacturing the same.

Printed Circuit Boards (PCBs) are like copper on electrically insulating substrates.

Is formed by printing a circuit line pattern with a conductive material, and refers to a board immediately before mounting an electronic component. That is, it means the circuit board which fixed the mounting position of each component, and printed and fixed the circuit pattern which connects components to the flat surface surface, in order to mount many electronic elements of various types densely on a flat plate.

Such printed circuit boards generally include a single layer PCB and a build-up board having multiple layers of PCBs, that is, a multilayer PCB substrate.

In particular, in recent years, system integration technology is required to reduce the size and lightness of electronic products, and technologies for manufacturing embedded PCB and cavity PCB have been attracting attention as corresponding technologies. Embedded PCBs have the advantage that the components mounted on the surface are completely embedded during the PCB process, providing a high degree of freedom in the design of wiring around embedded components, while reworking on the incomplete and defective parts of embedded components and PCB raw materials. This is difficult, and there is a problem that constraints occur in the part inspection method.

In the case of cavity PCB, the design freedom is lowered because the component is not completely embedded in the cavity and is mounted in the cavity where the space is formed in the direction in which the chip is mounted. However, the embedded PCB is embedded. There is a technical advantage that is very efficient in reworking and inspecting parts, which are problems in PCB). Cavity PCB, however, has been applied in many cases in which mold process based on law temperature co-fired ceramic (LTCC) has been applied, but it is a multilayer-by-layer technology. On the PCB, there are very few applications.

For this reason, it is difficult to form accurate cavity area and damage the internal circuit of cavity in the process of plating, image, etching, etc. generated during PCB process, which is very difficult to form. Because.

1A and 1B are conceptual views schematically illustrating a cavity forming process of a cavity printed circuit board according to the related art.

As shown, a plurality of circuit patterns 1a, 1b, 2a, 3a, 4a, and 6 are formed between each insulator in a structure in which multiple insulating layers 1, 2, 3, 4, and 5 are stacked. The process of forming the cavity C, which is a position where the electronic device chip is to be mounted on the printed circuit board, is a very difficult technology.

That is, as shown in Figure 1a, a method for selectively processing the position of the cavity (C) using a milling bit (M) in a printed circuit board in which the laminated state of the finished product is made, a number of methods are used Machining precision should be controlled at ± 5㎛, but in reality it is managed at about 50 ~ 100㎛, it is very difficult to process in reality, and the difference in processing precision becomes very severe, which is a fatal problem for product reliability during mass production. It appears to be a problem.

Alternatively, as shown in FIG. 1B, a method of selectively forming a cavity by precisely punching the position of the cavity through the punching machine P in the state of the finished product may be applied. However, this method punches the substrate of the C-stage through the punching edge, which inevitably leads to damage of the cavity outer wall, and the damage of the cavity outer wall exists in the CAF (Cathode Anode Filament) shot (prepreg) due to moisture absorption. When the glass filament is opened by punching, electric short is generated between vias 132, 142, and 152 inside the PCB), delamination, and damage to the lower surface of the cavity may occur. Price increases due to the manufacturing cost of the jig (P) and the width of the cavity design will lead to a very narrow problem.

The embodiment provides a printed circuit board having a new structure and a method of manufacturing the same.

The embodiment provides a printed circuit board for forming a cavity with a laser and a method of manufacturing the same.

In an embodiment, a printed circuit board including a cavity may include a base substrate, a circuit layer formed on or below the base substrate, and including a cavity circuit pattern exposed by the cavity, and forming the cavity. And an insulating layer filling the external circuit layer, wherein the base substrate includes an etching groove along an edge of the cavity.

In addition, the embodiment of the present invention provides a printed circuit board including a cavity, a base layer, a circuit layer formed on or below the base substrate, and including a cavity circuit pattern exposed by the cavity, forming the cavity, and And an insulating layer filling the circuit layer outside the cavity, and a cavity separation pattern filled by the insulating layer and surrounding the cavity.

Meanwhile, the method of manufacturing a printed circuit board according to the embodiment may include forming a base circuit board having upper and lower portions of a circuit circuit pattern in a cavity area and an internal circuit layer outside the cavity, and forming a cavity separation layer on the cavity circuit pattern. Forming at least one insulating layer and a circuit layer on the base circuit board, controlling the focal length of a laser to reach a surface of the substrate, and forming the insulating layer and the cavity separation layer on the etch stop pattern. And cutting the cavity separation layer and removing the cut insulation layer to form the cavity.

According to the present invention, the cavity separation layer is formed on the cavity circuit pattern, and the insulation layer is separated by cutting the cavity separation layer using a laser to easily remove the insulation layer in the cavity.

In addition, the degree of freedom of circuit design in the cavity may be increased by controlling the depth of etching by adjusting the focal length of the laser without forming an etching stopper at the boundary region of the cavity.

1A and 1B are cross-sectional views of a printed circuit board according to the prior art.
2 is a top view of a printed circuit board according to an exemplary embodiment of the present invention.
3 is a cross-sectional view taken along the line II ′ of the printed circuit board of FIG. 2.
FIG. 4 is an enlarged view illustrating region A of FIG. 3.
5 to 15 are cross-sectional views illustrating a method for manufacturing the printed circuit board of FIG. 2.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

In order to clearly illustrate the present invention in the drawings, thicknesses are enlarged in order to clearly illustrate various layers and regions, and parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification .

Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. On the contrary, when a part is "just above" another part, there is no other part in the middle.

The present invention proposes a printed circuit board which improves the degree of freedom in designing a circuit in a cavity by forming a cavity using a laser in a multilayer printed circuit board and controlling the focal length of the laser without an etch stop layer.

Hereinafter, a printed circuit board according to an exemplary embodiment of the present invention will be described with reference to FIGS. 2 to 15.

2 is a top view of a printed circuit board according to an exemplary embodiment of the present invention, FIG. 3 is a cross-sectional view taken along line II ′ of the printed circuit board of FIG. 2, and FIG. 4 is an enlarged view of region A of FIG. 3. It is also.

2 to 4, the printed circuit board 100 according to the present invention is a multilayer printed circuit board including a multilayer circuit pattern layer, and includes a base circuit board including an internal circuit layer 120.

The base circuit board includes a base substrate 110 and an internal circuit layer 120 formed above and below the base substrate 110.

The base substrate 110 may be a thermosetting or thermoplastic polymer substrate, a ceramic substrate, an organic-inorganic composite material substrate, or a glass fiber impregnated substrate, and may include an epoxy-based insulating resin as the insulating substrate. Alternatively, it may alternatively include a polyimide-based resin.

Internal circuit layers 120 are formed on upper and lower portions of the base substrate 110, and a part of the internal circuit layers 120 is exposed to a cavity region in which a cavity C having a first width d1 is formed. And 125.

The cavity circuit pattern 125 extends from the bottom surface of the cavity C and extends on the same plane as the internal circuit layer 160 embedded in an insulating layer surrounding the cavity C.

At this time, the base substrate 110 is formed with an etching groove (LS: laser spot) along the edge region of the cavity (C).

The etching groove LS is formed by laser drilling to form the cavity C, and is formed to a predetermined depth along the edge region.

The internal circuit layers 120 other than the cavity circuit pattern 125 are buried by the first insulating layer 130, and a plurality of insulating layers 140 and 150 are formed on the first insulating layer 130. .

The second insulating layer 140 and the third insulating layer 150 formed on the first insulating layer 130 may be a resin insulating layer formed of the same material.

In FIG. 3, three insulating layers 130, 140, and 150 are formed, but the number of insulating layers may be variously modified, and different numbers of insulating layers and interlayer circuit layers may be formed on upper and lower portions of the base circuit board. Can be.

Interlayer circuit layers (not shown) are formed between the first to third insulating layers 130, 140, and 150, and interlayers are formed on the first to third insulating layers 130, 140, and 150. Vias 132, 142, and 152 connecting the circuit layers are formed.

The plurality of insulating layers 130, 140, and 150 may be stacked, the interlayer circuit layer may be formed, and the vias 132, 142, and 152 may be formed through a general build-up process.

The external circuit layer 154 is formed on the third insulating layer 150 defined as the uppermost layer in the printed circuit board 100 of FIG. 3, and connects the external circuit layer 154 and the lower interlayer circuit layer. Via 152 is formed.

The printed circuit board 100 may include a conductive through hole 155 penetrating through the lowermost layer of the uppermost layer of the printed circuit board 100.

The coverlay 160 exposing the upper circuit layer 154 and exposing the through hole 155 and the via 152 may be stacked on the third insulating layer 150.

The coverlay 160 may be a dry film or a solder resist.

At this time, when the inside of the cavity C is examined in detail, a plurality of cavity circuit patterns 125 are formed in the cavity area forming the cavity C having the first width d1.

As described above, an etch groove LS is formed in the edge region of the cavity C, surrounding the cavity circuit pattern 125, and formed in the cavity circuit pattern 125 and the first insulating layer 130. An etching groove LS is not formed in a region in which a connection pattern connecting the internal circuit layer 120 buried by the internal circuit layer 120 is formed.

The etching groove LS is formed by laser drilling, and the connection pattern serves as a stopper of the laser drilling.

As such, since the laser stopper is not formed, the cavity circuit pattern 125 and the internal circuit layer 120 can be connected in the same layer, thereby increasing the degree of freedom in circuit design and reducing the thickness of the circuit board.

In this case, a portion of the cavity separation layer 129 is formed around the cavity C in the first insulating layer 130 surrounding the cavity C. The cavity isolation layer 129 is embedded in the first insulating layer 130 at a position higher than the metal layer forming the internal circuit layer 120 and the cavity circuit pattern 125.

The cavity separation layer 129 is a material having a heat resistance that is less adhesive force with the metal forming the lower cavity circuit pattern 125 than the first insulating layer 130, and preferably in the form of a tape. It may be part of a release film composed of.

The cavity separation layer 129 may be an insulating layer in the form of a tape formed using any one of an epoxy, a phenol resin, a prepreg, a polyimide, and ABF, and may preferably be part of a polyimide tape.

As described above, the cavity C is formed by cutting the insulating layers 130, 140, 150 and the cavity separation layer 129 with a laser without forming a stopper in the edge region of the cavity C for laser drilling. The design of the cavity circuit pattern 125 is free.

Hereinafter, a method of manufacturing the printed circuit board of FIG. 2 will be described with reference to FIGS. 5 to 15.

First, as shown in FIG. 5, a copper foil composite having a metal layer 121 formed on both surfaces of an insulating base substrate 110 is prepared.

The metal layer 121 may be a copper foil including copper, but may be an alloy including aluminum, gold, silver, and the like.

Next, as shown in FIG. 5, the internal circuit layer 120 is formed by patterning the metal layers 121 on both sides of the base substrate 110.

A part of the internal circuit layer 120 is a cavity circuit pattern 125 to be exposed to the cavity C, and is formed by etching the same metal layer as the internal circuit layer 120 formed in a region other than the cavity C. It is formed to be.

Next, the structure including the internal circuit layer 120 formed on both sides of the base substrate 110 as shown in Figure 6 is defined as a base circuit board.

 Next, as shown in FIG. 7, a solder resist (PSR) 127 is printed in the cavity region, and the solder resist 127 of the cavity region is exposed to expose the cavity circuit pattern 125 in the cavity region. Likewise, a structure in which the solder resist pattern 126 is formed is formed.

Thereafter, a process of forming a surface treatment layer 128 by oxidizing the surface of the cavity circuit pattern 125 may be added as shown in FIG. 9.

The surface treatment layer 128 may be formed by performing a plating treatment in a single layer or a multilayer using any one of Cu, Ni, Pd, Au, Sn, Ag, Co, or a binary or ternary alloy thereof. It is also possible.

Next, as shown in FIG. 10, a heat resistant cavity separation layer 129 having weak adhesion in the cavity region is formed.

The cavity separation layer 129 is formed to have a wider width than the cavity area, and covers the cavity area.

The cavity separation layer 129 serves as a separation layer exposing the cut and cut insulation layer 130 together with the insulation layer 130 when the cavity region is later processed by a laser drill.

The cavity separation layer 129 may be formed of a heat-resistant material having a weak adhesive force, and particularly preferably, in the form of a tape for the convenience of the process, to facilitate detachment and detachment. For example, it may be formed of an insulating layer formed using any one of epoxy, phenol resin, prepreg, polyimide, and ABF, and preferably, the cavity separation layer 129 by attaching a PI (polyimide) tape. ) Can be easily formed.

Next, as shown in FIGS. 11 and 12, at least one insulating layer 130 and a metal layer 135 are stacked and patterned on the upper or lower portion of the base substrate 110 to sequentially form an interlayer circuit layer.

Repeating the process of FIGS. 11 and 12, a portion of the insulating layer 130 is opened to expose the lower interlayer circuit layer, and vias 132, 142, and 152 are formed by plating to form the multilayer circuit board of FIG. 13. To form.

In this case, a conductive through hole 155 penetrating from the top to the bottom of the multilayer circuit board may be formed, and the vias 132, 142, and 152 electrically connected to the internal circuit layer 120 and other circuit layers may be formed. A general build-up process may be performed.

When the external circuit layer 154 is formed on the third insulating layer 150, which is the outermost insulating layer, the coverlay 160 is formed on the third insulating layer 150 by using a solder resist or the like.

The coverlay 160 fills the external circuit layer 154 and is formed to expose the outermost via 152 and the through hole 155.

Next, the cavity C is formed in the cavity region of the multilayer circuit board of FIG. 13.

In the process of forming the cavity C, as shown in FIG. 14, the position where the cavity C is to be processed is arranged using the laser drill 200, and the focal length of the laser drill 200 is controlled to control the laser drill ( 200, the etching groove LS having a predetermined depth is formed on the surface of the base substrate 110.

Such laser drilling proceeds from the outermost surface to the surface of the base substrate 110.

Next, as shown in FIG. 15, when the insulating layers 130, 140, and 150 of the cavity region separated by the laser drill 200 are exposed, the insulating layer of the cavity region may be formed due to the low adhesive force of the cavity separation layer 129. 130, 140, 150 are easily removed.

As such, the cavity C may be formed without a separate metal stopper by controlling the focal length of the laser drill 200 to allow the cutting to proceed as much as the depth of the set cavity C.

Accordingly, the cavity C of FIG. 15 is formed, and the passive circuit or the active device electrically connected to the cavity circuit pattern 125 may be mounted in the cavity C by exposing the cavity circuit pattern 125.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Printed Circuit Board 100
Base Board 110
Internal circuit layer 120
Cavity C
Laser drill 200

Claims (17)

In a printed circuit board comprising a cavity,
Base substrate,
A base circuit layer formed on or below the base substrate, the base circuit layer including a cavity circuit pattern exposed by the cavity; and
An insulation layer forming the cavity and filling the base circuit layer outside the cavity;
The base substrate is a printed circuit board including an etching groove along the edge of the cavity. The method of claim 1,
And a cavity separation layer filled by the insulating layer and surrounding the cavity. The method of claim 1,
The insulating layer is a printed circuit board formed of at least one insulating film. The method of claim 1,
The insulating layer is formed on top and bottom of the base substrate. The method of claim 1,
The etching groove is a printed circuit board formed by a laser drill to form the cavity. The method of claim 2,
The cavity separation layer is part of a polyimide tape. The method of claim 1,
A printed circuit board having a solder resist pattern formed between the cavity circuit pattern. Forming a base circuit board on the upper and lower sides of the substrate, the base circuit board having an internal circuit layer outside the cavity;
Forming a cavity separation layer on the cavity circuit pattern;
Forming at least one insulating layer and a circuit layer on the base circuit board,
Cutting the insulating layer and the cavity separation layer on the cavity circuit pattern by controlling the focal length of the laser to reach the surface of the base circuit board; and
Separating the cavity separation layer to remove the cut insulation layer to form the cavity
And a step of forming the printed circuit board. The method of claim 8,
Forming the base circuit board,
Patterning the cavity circuit pattern and the internal circuit layer on both sides of a base substrate, and
Forming a solder resist pattern between the cavity circuit pattern. The method of claim 8,
And forming an oxide layer on the cavity circuit pattern. The method of claim 8,
Forming the at least one insulating layer and the circuit layer,
And sequentially forming at least one insulating layer and a circuit layer on the base circuit board, and forming vias electrically connecting the internal circuit layer and the circuit layer. The method of claim 8,
The insulating layer cutting step,
And controlling the focal length of the laser to irradiate the laser to form an etching groove on the surface of the base substrate. The method of claim 8,
Forming the cavity separation layer,
A method of manufacturing a printed circuit board, wherein an insulating tape is attached onto the cavity circuit pattern. The method of claim 8,
Forming the cavity separation layer,
And attaching the cavity separation layer to have a width greater than that of the cavity. In a printed circuit board comprising a cavity,
Base substrate,
A circuit layer formed on or below the base substrate and including a cavity circuit pattern exposed by the cavity;
An insulation layer forming the cavity and filling the circuit layer outside the cavity; and
A printed circuit board comprising a cavity separation layer buried by the insulating layer surrounding the cavity. 16. The method of claim 15,
The cavity separation layer is part of a polyimide tape. 16. The method of claim 15,
The cavity separation layer is formed higher than the circuit layer in the insulating layer.

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