KR101125356B1 - The printed circuit board and the method for manufacturing the same - Google Patents

Abstract

PURPOSE: A printed circuit board and a manufacturing method thereof are provided to easily eliminate an insulating layer within a cavity by using a weak contact force between a cavity parting layer and a cavity circuit pattern. CONSTITUTION: An internal circuit layer(120) is formed in the upper and lower side of a base substrate(110). The internal circuit layer comprises a cavity circuit pattern(125) which is exposed to a cavity area. The cavity circuit pattern comprises an etch-stop layer(124) straddled on an edge region of a cavity(C). The etch-stop layer is extended along the edge of the cavity. The internal circuit layer is buried by a first insulation layer(130). A second insulation layer(140) and a third insulation layer(150) are formed on the first insulation layer. An interfacial layer is formed between the first insulation layer and the second insulation layer, and the second insulation layer and the third insulation layer.

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.

A printed circuit board (PCB) is formed by printing a circuit line pattern on a electrically insulating substrate with a conductive material such as copper, 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 includes a base substrate, a cavity circuit pattern formed on or above the base substrate, and an etch stop pattern formed on an edge region of the cavity. An insulating layer forming a circuit layer, the cavity, and filling a portion of the circuit layer and the etch stop pattern, a resist pattern formed on a portion of the etch stop pattern filled by the insulating layer, and the insulating layer It includes a cavity separation pattern formed on the resist pattern is buried by.

The method of manufacturing a printed circuit board according to the embodiment may include forming a base circuit board having a cavity circuit pattern on the surface of the substrate and an internal circuit layer including an etch stop pattern along an edge of the cavity, wherein the cavity circuit pattern is formed. And forming a resist layer on the etch stop pattern, forming a cavity isolation layer on the resist layer, forming at least one insulating layer and a circuit layer on the base circuit board, and drilling the laser to remove the etch stop. Cutting the insulating layer and the cavity separation layer on the pattern, separating the etch stop pattern and the cavity separation layer to remove the cut insulation layer to form a cavity, and peeling the resist layer to the Exposing a cavity circuit pattern in the cavity.

According to the present invention, by forming a resist layer and a cavity separation layer on the cavity circuit pattern, and using a laser to the cavity separation layer after the cutting to peel off the resist layer using a weak adhesion between the cavity separation layer and the metal cavity circuit pattern. By separating the insulating layer, the insulating layer in the cavity can be easily removed, and the remaining cavity separation layer can be removed together with the removal of the resist layer.

In addition, when the cavity circuit pattern is formed in the boundary region of the cavity and drilled with a laser to form the cavity, the cavity circuit pattern may function as an etch stopper to form a cavity to a target depth.

1A and 1B are cross-sectional views of a printed circuit board according to the prior art.
2 is a cross-sectional view of a printed circuit board according to an exemplary embodiment of the present invention.
FIG. 3 is an enlarged view illustrating region A of FIG. 2.
4 through 16 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 can easily remove the insulating layer in the cavity after laser drilling using a cavity separation layer on the etch stop layer in the cavity, while forming a cavity (cavity) using a laser in a multilayer printed circuit board, the etch stop layer The present invention provides a printed circuit board capable of removing the remaining etch stop layer by further forming a resist layer between the cavity and the cavity separation layer and then removing the insulating layer in the cavity.

Hereinafter, a printed circuit board according to an exemplary embodiment of the present invention will be described with reference to FIGS. 2 to 16.

2 is a cross-sectional view of a printed circuit board according to an exemplary embodiment of the present invention, and FIG. 3 is an enlarged view of region A of FIG. 2.

2 and 3, 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 includes an etch stop layer 124 over an edge region of the cavity C.

The etch stop layer 124 extends along an edge of the cavity C, and includes a third width d3 inside the cavity C and a second width d2 outside the cavity C. It is formed having a fourth width d4.

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. 2, three insulating layers 130, 140, and 150 are illustrated, 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. 2, 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, the etch stop layer 124 of the cavity circuit pattern 125 extends over the edge of the cavity C, and extends from the edge to the outside of the cavity C by a second distance d2.

The etch stop layer 124 functions as a stopper during laser drilling for forming the cavity C, and a part of the etch stop layer 124 is exposed in the cavity area, and the rest is other than the cavity. It is buried by the first to third insulating layers (130, 140, 150) in the region of.

In this case, a portion of the resist layer 123 and the cavity separation layer 129 on the etch stop layer 124 of the second width d2 buried by the first to third insulating layers 130, 140, and 150. Are stacked.

The resist layer 123 may be photosensitive resist ink as the resist ink, and may be a liquid type resist ink or a peeling type photosensitive ink.

A cavity separation layer 129 is formed on the resist layer 123.

The cavity separation layer 129 is a material having a heat resistance that is less than the adhesive strength with the ink forming the lower resist layer 123 than the first insulating layer 130, and preferably in the form of a tape It may be part of the configured release film.

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 metal etch stop layer 124 is formed on the edge region of the cavity C for laser drilling, and the cavity separation layer 129 is attached on the etch stop layer 124 to separate the cavity after laser drilling. By the layer 129, the insulating layer which filled the cavity C can be easily removed.

In addition, by forming the resist layer 123 under the cavity separation layer 129, the adhesive component remaining after the cavity separation layer 129 is removed may be removed together with the removal of the resist layer 123.

Hereinafter, a method of manufacturing the printed circuit board of FIG. 2 will be described with reference to FIGS. 4 to 16.

First, as shown in FIG. 4, 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 portion of the internal circuit layer 120 is a cavity circuit pattern 125 to be exposed to the cavity C, and together forms an etch stop layer 124 having a fourth width d4 along the edge of the cavity region. .

In this case, the etch stop layer 124 has a second width d2 outside the cavity region and is formed in the edge region of the cavity C so as to have a third width d3 into the cavity region.

As shown in FIG. 5, a structure including an internal circuit layer 120 formed on both sides of the base substrate 110 is defined as a base circuit board.

 Next, as shown in FIG. 6, a solder resist (PSR) 127 is printed in the cavity area, and the solder resist 127 of the cavity area is exposed to expose the cavity circuit pattern 125 in the cavity area. 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. 8.

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. 9, resist ink is applied to the cavity C region to form a resist layer 123.

The resist layer 123 may be formed to cover up to the second width d2 of the cavity C region and the etch stop layer 124. Alternatively, the resist layer 123 may have a third width d3 of the etch stop layer 124. It may be formed to cover only up to).

When the resist layer 123 is formed only up to the third width d3 of the etch stop layer 124, the resist layer 123 does not remain between the etch stop layer 124 and the cavity separation layer 129 in FIG. 2. You may not.

The resist layer 123 may be formed by applying a liquid type resist ink, and a cavity separation layer 129 is formed on the resist layer 123 as shown in FIG. 10 without curing.

The cavity separation layer 129 is formed to have a wider width than the cavity C area, covers all the cavity C areas, and covers the second width d2 of the etch stop layer 124. Form.

Accordingly, the etch stop layer 124, the resist layer 123, and the cavity separation layer 129 are stacked at the edge of the cavity C region.

The cavity separation layer 129 serves as a separation layer exposing the cut insulation layer cut along with the insulation layer when the cavity C 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 by using any one of epoxy, phenol resin, prepreg, polyimide, ABF, and more preferably formed of a tape material of the material. As a preferred example, the cavity separation layer 129 can be simply formed by attaching a PI (polyimide) tape.

The cavity separation layer 129 may have a higher adhesive force than a surface attached to the insulating layer 123.

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 or the like, thereby forming the multilayer circuit board of FIG. 12. 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.

As shown in FIG. 13, 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. Form.

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. 14.

The process of forming the cavity C aligns the position where the cavity C is to be processed by using the laser drill 200 and toward the etch stop layer 124 of the cavity circuit pattern 125 as shown in FIG. 14. Perform laser drilling.

The laser drilling proceeds from the uppermost layer to the etch stop layer 124, and when the cavity separation layer 129 on the etch stop layer 124 is cut and the laser drill 200 reaches the etch stop layer 124, the laser drilling is automatically performed. Will stop.

Next, as shown in FIG. 15, when the insulating layer of the cavity region separated by the laser drill 200 is exposed, the cavity region is insulated by the low adhesive force between the cavity separation layer 129 and the resist layer 123 below. The layer is easily removed.

In this way, the edge of the portion to be removed of the cut cavity separation layer 129 is adhered to the resist layer 123 and can be removed by easily falling off the edge by a weak adhesive force.

Finally, as shown in FIG. 16, when the resist layer 123 formed on the cavity circuit pattern 125 is peeled off using a stripping solution, for example, NaOH, the residue remains on the resist layer 123 and the resist layer 123. A portion of the cavity separation layer 129 is removed together.

Accordingly, the cavity C of FIG. 16 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 (15)

In a printed circuit board comprising a cavity,
Base substrate,
A circuit layer formed on an upper portion or a lower portion of the base substrate, the circuit layer including a cavity circuit pattern exposed by the cavity and an etch stop pattern formed in an edge region of the cavity;
An insulating layer forming the cavity and filling a portion of the circuit layer and the etch stop pattern;
A resist pattern formed on a portion of the etch stop pattern buried by the insulating layer, and
Cavity separation pattern formed on the resist pattern buried by the insulating layer
Printed circuit board comprising a. 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,
A portion of the etch stop pattern is exposed in the cavity,
The remaining area is embedded in the insulating layer. The method of claim 1,
The cavity separation pattern is a printed circuit board having an adhesive strength of the surface to be bonded to the resist pattern is less than the adhesive strength of the surface to be bonded to the insulating layer. The method of claim 1,
The cavity separation pattern 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. The method of claim 1,
The resist pattern is a printed circuit board formed of a resist ink. Forming a base circuit board having a cavity circuit pattern on the surface of the substrate and an inner circuit layer including an etch stop pattern along an edge of the cavity;
Forming a resist layer on the cavity circuit pattern and the etch stop pattern;
Forming a cavity separation layer on the resist layer;
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 etch stop pattern by drilling with a laser;
Separating the etch stop pattern and the cavity separation layer to remove the cut insulation layer to form a cavity; and
Exfoliating the resist layer to expose a cavity circuit pattern in the cavity
Method of manufacturing a printed circuit board comprising a cavity comprising a. 10. The method of claim 9,
Forming the base circuit board,
Patterning an internal circuit layer including the cavity circuit pattern and the etch stop pattern on both sides of a base substrate, and
Forming a solder resist pattern between the cavity circuit pattern. 10. The method of claim 9,
And forming an oxide layer on the cavity circuit pattern. 10. The method of claim 9,
Forming the cavity separation layer,
A method of manufacturing a printed circuit board for attaching an insulating tape on the etch stop pattern and the cavity circuit pattern. 10. The method of claim 9,
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. 10. The method of claim 9,
Forming the resist layer,
A method of manufacturing a printed circuit board for applying a resist ink to a portion of the cavity circuit pattern and the etch stop pattern. 10. The method of claim 9,
Removing the resist layer
A method of manufacturing a printed circuit board using the release liquid to remove the resist layer in the cavity.

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