KR20210121776A - Printed circuit board, package board and manufacturing method thereof - Google Patents

Abstract

In accordance with an embodiment of the present invention, a printed circuit board comprises: a first insulation layer; a second insulation layer placed on the first insulation layer and including a cavity; and a plurality of pads placed on the first insulation layer and having an upper surface exposed through the cavity. The cavity of the second insulation layer includes: a floor surface placed higher than the upper surface of the first insulation layer; and an inner wall extended from the floor surface. The inner wall is vertical to an upper surface or a lower surface of the second insulation layer. The floor surface of the cavity includes: a first floor surface placed lower than an upper surface of the pads, and placed on an outer side of the placement area of the plurality of pads; and a second floor surface placed lower than the upper surface of the pads, and placed on an inner side of the placement area of the plurality of pads. A height of the first floor surface is different from a height of the second floor surface. The present invention aims to provide the printed circuit board, a package board, and a manufacturing method of the printed circuit board, which are capable of improving the product reliability.

Description

Printed circuit board, package board, and manufacturing method thereof

The embodiment relates to a printed circuit board, a package board, and a method of manufacturing the same.

The printed circuit board has a structure in which the mounting position of each element is determined and a circuit pattern connecting the elements is printed and fixed on the surface of the flat plate in order to densely mount various kinds of elements on the flat plate, or the elements are installed on the inside of the printed circuit board. It is composed of an embedded structure in the form of being embedded.

Recently, in order to realize miniaturization and multifunctionality of electronic components, printed circuit boards have been used in a multi-layered structure capable of high-density integration.

In general, the conventional embedded printed circuit board forms a cavity for embedding a device using a drill bit, or uses an auxiliary material such as a release film for mounting the device, or sandblasting ( A cavity for embedding the device was formed using sand blast).

However, in the cavity included in the conventional printed circuit board, the inclination angle of the inner wall is formed to be 150° or more with respect to the bottom surface of the cavity. Accordingly, there is a problem in that the space required for forming the cavity is relatively large. Accordingly, the conventional printed circuit board has a problem in that the degree of circuit integration is reduced and the overall volume of the printed circuit board increases as the cavity formation space increases.

The embodiment relates to a printed circuit board capable of improving an inclination angle of an inner wall of a cavity, a package board, and a method of manufacturing the same.

Further, in the embodiment, a printed circuit board capable of removing a stop layer required for a bottom surface of a cavity in a cavity forming process, a package substrate, and a manufacturing method thereof can be provided.

The technical problems to be achieved in the proposed embodiment are not limited to the technical problems mentioned above, and other technical problems not mentioned are clear to those of ordinary skill in the art to which the proposed embodiment belongs from the description below. will be able to be understood

A printed circuit board according to an embodiment includes a first insulating layer; a second insulating layer disposed on the first insulating layer and including a cavity; a plurality of pads disposed on the first insulating layer and having a top surface exposed through the cavity, wherein the cavity of the second insulating layer has a bottom surface positioned higher than the top surface of the first insulating layer; an inner wall extending from a bottom surface, wherein the inner wall is perpendicular to an upper surface or a lower surface of the second insulating layer, a bottom surface of the cavity is located lower than an upper surface of the pad, and an arrangement area of the plurality of pads a first bottom surface positioned outside the pad; 2 It is different from the height of the floor surface.

In addition, the height of the first bottom surface is greater than the height of the second bottom surface.

In addition, the height of at least one of the first bottom surface and the second bottom surface decreases from the outside to the inside.

In addition, the combination shape of the first bottom surface and the second bottom surface has a V-shape.

In addition, the upper width of the cavity is the same as the lower width of the cavity.

In addition, the thickness of the second insulating layer has a range of 5um to 20um.

In addition, the second insulating layer includes resin coated copper (RCC).

In addition, the cavity includes a corner surface between the inner wall and the bottom surface, and the corner surface has a curved surface.

On the other hand, the package substrate according to the embodiment includes a first insulating layer; a second insulating layer disposed on the first insulating layer and including a cavity; a plurality of pads disposed on the first insulating layer and having an upper surface exposed through the cavity; a connection portion disposed on the plurality of pads; and an electronic device disposed on the connection part, wherein the cavity of the second insulating layer includes a bottom surface positioned higher than an upper surface of the first insulating layer, an inner wall extending from the bottom surface, the inner wall and the a corner surface between the bottom surfaces, wherein the inner wall is perpendicular to an upper surface or a lower surface of the second insulating layer, and the corner surface has a curved surface.

In addition, the bottom surface of the cavity is located lower than the top surface of the pad, the first bottom surface is located outside the arrangement area of the plurality of pads, is located lower than the top surface of the pad, and a second bottom surface positioned inside the arrangement area, wherein a height of the first floor surface is different from a height of the second floor surface.

In addition, the height of the first bottom surface is greater than the height of the second bottom surface, and at least one of the first bottom surface and the second bottom surface decreases in height from the outside to the inside.

In addition, the combination shape of the first bottom surface and the second bottom surface has a V-shape.

In addition, the upper width of the cavity is the same as the lower width of the cavity.

In addition, the second insulating layer includes resin coated copper (RCC) and has a thickness in a range of 5 μm to 20 μm.

It also includes a molding layer disposed in the cavity and covering at least a portion of the electronic device.

Meanwhile, in the method of manufacturing a printed circuit board according to the embodiment, a first insulating layer is prepared, a plurality of pads are formed on an upper surface of the first insulating layer, and a jig is formed on the plurality of pads of the first insulating layer. and using the jig to form a second insulating layer in a region other than the region where the jig is disposed among the upper regions of the first insulating layer, and to separate the jig from the second insulating layer, and forming a cavity in a region in which is disposed, the second insulating layer includes resin coated copper (RCC), and the cavity of the second insulating layer is located higher than the upper surface of the first insulating layer a bottom surface and an inner wall extending from the bottom surface, the inner wall being perpendicular to an upper surface or a lower surface of the second insulating layer, a bottom surface of the cavity is located lower than an upper surface of the pad, and the plurality of a first bottom surface positioned outside the pad disposition area; and a second bottom surface positioned lower than the upper surface of the pad and positioned inside the plurality of pad disposition areas, wherein the height of the first bottom surface is , greater than the height of the second bottom surface.

In addition, the height of at least one of the first bottom surface and the second bottom surface decreases from the outside to the inside, the combination shape of the first bottom surface and the second bottom surface has a V shape, and the cavity The upper width of is equal to the lower width of the cavity.

The method may further include desmearing the cavity of the second insulating layer, wherein an edge surface between the inner wall and the bottom surface of the cavity has a curved surface.

According to an embodiment, the printed circuit board includes a cavity. In addition, the cavity of the printed circuit board has a non-penetrating structure rather than a structure penetrating the second insulating layer. In this case, the cavity exposes the pad disposed on the upper surface of the first insulating layer. In this case, the bottom surface of the cavity is positioned lower than the top surface of the pad. Accordingly, in the embodiment, it is not necessary to form an additional stop layer on the upper surface of the first insulating layer to form the cavity, and thus processes such as formation and removal of the stop layer can be omitted. have. In addition, in the embodiment, it is possible to solve a reliability problem due to a change in the thickness or shape of the pad that may occur in the process of removing the blocking layer in the comparative example, and thus product reliability can be improved.

In addition, the cavity of the printed circuit board in the embodiment includes a bottom surface and an inner wall. In this case, the bottom surface of the cavity may have different heights depending on the location. In other words, the bottom surface of the cavity may have a shape in which the height gradually decreases from the outside to the inside. Accordingly, when an additional molding layer is formed on the bottom surface of the cavity, a contact area with the molding layer may be increased, and thus product reliability may be improved.

In addition, the cavity of the printed circuit board in the embodiment is formed using a jig. And, the shape of the cavity may correspond to the shape of the jig. For example, the cavity may have an upper width and a lower width equal to each other. In this case, the inclination angle of the inner wall of the cavity in the comparative example may be perpendicular to the main surface.

In the above embodiment, the inclination angle of the inner wall can be reduced compared to the comparative example, and accordingly, on the assumption that the same element is disposed, the space required for cavity formation can be minimized compared to the comparative example, and thus the circuit integration can be improved. can In other words, by forming the inclination angle of the inner wall in the embodiment to be substantially vertical, more circuits can be formed in the same area compared to the comparative example, and thus the overall volume of the printed circuit board can be reduced.

1A is a view showing a printed circuit board according to a first embodiment.
1B is a view showing a printed circuit board according to a second embodiment.
FIG. 2A is an enlarged view of the cavity area of FIG. 1A .
FIG. 2B is an enlarged view of the cavity area of FIG. 1B .
3 is a view showing a package substrate according to the first embodiment.
4 is a view showing a package substrate according to a second embodiment.
5 to 9 are views showing the manufacturing method of the printed circuit board shown in FIG. 1B in order of process.
10 is a view showing a printed circuit board according to a third embodiment.
11 to 14 are views showing the manufacturing method of the printed circuit board shown in FIG. 10 in order of process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components may be selected among the embodiments. It can be combined and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention pertains, unless specifically defined and described. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art. In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as "at least one (or more than one) of A and (and) B, C", it is combined with A, B, C It can contain one or more of all possible combinations. In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are only used to distinguish the component from other components, and are not limited to the essence, order, or order of the component by the term. And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include a case of 'connected', 'coupled' or 'connected' due to another element between the other elements.

In addition, when it is described as being formed or disposed on "above (above) or below (below)" of each component, the top (above) or bottom (below) is one as well as when two components are in direct contact with each other. Also includes a case in which another component as described above is formed or disposed between two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upper direction but also a lower direction based on one component may be included.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A is a view showing a printed circuit board according to a first embodiment, FIG. 1B is a view showing a printed circuit board according to a second embodiment, FIG. 2A is an enlarged view of the cavity area of FIG. 1A, and FIG. 2B is an enlarged view of the cavity area of FIG. 1B.

1A, 1B, 2A and 2B , the printed circuit board 100 includes a first insulating layer 110 , a second insulating layer 120 , a third insulating layer 130 , and a circuit pattern 141 . , 141 , 143 , 144 , 145 , 146 , 147 , 148 , vias V1 , V2 , V3 , V4 , V5 , V6 , V7 , and protective layers 151 and 152 .

The first insulating layer 110 may be an insulating layer disposed in the center of the printed circuit board 100 .

The second insulating layer 120 is disposed on the first insulating layer 110 .

In addition, the third insulating layer 130 is disposed under the first insulating layer 110 .

In this case, although the first insulating layer 110 is illustrated as being disposed in the center layer in the overall stacked structure of the printed circuit board 100 in the drawing, the present invention is not limited thereto. That is, the first insulating layer 110 may be disposed at a position biased toward the upper side in the entire stacked structure of the printed circuit board 100 , or, conversely, may be disposed at a position biased toward the lower side.

Here, referring to FIG. 1A , the second insulating layer 120 is disposed on the first insulating layer 110 . In this case, the second insulating layer 120 has a plurality of layer structures. For example, the second insulating layer 120 is disposed on the 2-1 th insulating layer 121 disposed on the upper surface of the first insulating layer 110 and on the upper surface of the 2-1 th insulating layer 121 . It may include a 2-2nd insulating layer 122 and a 2-3rd insulating layer 123 disposed on the upper surface of the 2-2nd insulating layer 122 . At this time, although it is illustrated that the second insulating layer 120 has a three-layer structure in the drawings, the present invention is not limited thereto. That is, the second insulating layer 120 may be composed of two or less layers, or alternatively, it may be configured with a structure of four or more layers.

Also, referring to FIG. 1A , a third insulating layer 130 is disposed under the first insulating layer 110 . In this case, the third insulating layer 130 has a plurality of layer structures. For example, the third insulating layer 130 may include a 3-1 insulating layer 131 disposed under the lower surface of the first insulating layer 110 and a lower surface of the 3-1 insulating layer 131 . It may include a 3-2nd insulating layer 132 disposed in the , and a 3-3rd insulating layer 133 disposed under a lower surface of the 3-2nd insulating layer 132 . In this case, although it is illustrated that the third insulating layer 130 has a three-layer structure in the drawings, the present invention is not limited thereto. That is, the second insulating layer 130 may be composed of two or less layers, or alternatively, it may be configured with a structure of four or more layers.

In addition, although the printed circuit board 100 is illustrated as having a seven-layer structure based on the insulating layer in the drawings, the present invention is not limited thereto. For example, the printed circuit board 100 may have a number of layers of 6 or less based on the insulating layer, or alternatively, may have a number of layers of 8 or more.

Meanwhile, although it has been described that the second insulating layer 120 and the third insulating layer 130 have a plurality of layer structures in FIG. 1A , the present invention is not limited thereto. For example, the second insulating layer 120 and the third insulating layer 130 may be configured as a single layer.

That is, as shown in FIG. 1B , a second insulating layer 120 and a third insulating layer 130 of one layer may be disposed above and below the first insulating layer 110 , respectively.

Accordingly, in FIG. 1A , a cavity (described later) is formed in the second insulating layer 120 composed of a plurality of layers, and thus the cavity may have a plurality of layer structures.

Also, in FIG. 1B , a cavity may be formed in the second insulating layer 120 configured as a single layer.

That is, the difference between the first embodiment in FIG. 1A and the second embodiment in FIG. 1B is in whether the second insulating layer is composed of a plurality of layers or a single layer. In addition, the difference between the first embodiment in FIG. 1A and the second embodiment in FIG. 1B is whether the cavity formed in the second insulating layer is formed by processing a plurality of layers or by processing a single layer. .

In other words, the second insulating layer 120 in the embodiment may be composed of a plurality of layers, otherwise, may be composed of a single layer. In addition, a cavity may be formed in the second insulating layer 120 of a plurality of layers or a single layer.

The first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 are substrates on which an electric circuit capable of changing wiring is formed, and are made of an insulating material capable of forming circuit patterns on the surface. It may include all the manufactured printed circuit boards, wiring boards, and insulating boards.

For example, the first insulating layer 110 may be rigid or flexible. For example, the first insulating layer 110 may include glass or plastic. In detail, the first insulating layer 110 may include chemically strengthened/semi-tempered glass such as soda lime glass or aluminosilicate glass, polyimide (PI), or polyethylene terephthalate. , PET), propylene glycol (PPG), reinforced or soft plastic such as polycarbonate (PC), or may include sapphire.

In addition, the first insulating layer 110 may include an optical isotropic film. For example, the first insulating layer 110 may include cyclic olefin copolymer (COC), cyclic olefin polymer (COP), optical isotropic polycarbonate (PC), or optical isotropic polymethyl methacrylate (PMMA). can

Also, the first insulating layer 110 may be bent while having a partially curved surface. That is, the first insulating layer 110 may be bent while partially having a flat surface and partially having a curved surface. In detail, the first insulating layer 110 may have a curved end with a curved surface, or may have a surface including a random curvature and may be bent or bent.

In addition, the first insulating layer 110 may be a flexible substrate having a flexible characteristic. Also, the first insulating layer 110 may be a curved or bent substrate.

Meanwhile, the second insulating layer 120 and the third insulating layer 130 may be made of resin coated copper (RCC).

That is, all of the plurality of layers constituting the second insulating layer 120 and the third insulating layer 130 in the first embodiment may be composed of RCC.

In addition, each single layer constituting the second insulating layer 120 and the third insulating layer 130 in the second embodiment may be composed of RCC.

Accordingly, the second insulating layer 120 and the third insulating layer 130 may have a thickness of 5 μm to 20 μm. For example, when the second insulating layer 120 has a plurality of layer structures, each of the plurality of layers may have a thickness of 5 μm to 20 μm. Also, when the second insulating layer 120 has a single layer, the thickness of the second insulating layer 120 of the single layer may be 5 μm to 20 μm.

That is, the insulating layer constituting the circuit board in the comparative example was composed of a prepreg (PPG) containing glass fibers. In this case, it is difficult to reduce the thickness of the glass fiber based on the PPG in the circuit board in the comparative example. This is because, when the thickness of the PPG decreases, the glass fibers included in the PPG may be electrically connected to a circuit pattern disposed on the surface of the PPG, and thus a crack list is induced. Accordingly, when the thickness of the PPG is reduced in the circuit board of the comparative example, dielectric breakdown and damage to the circuit pattern may occur. Accordingly, the circuit board in the comparative example has a limit in reducing the overall thickness due to the thickness of the glass fibers constituting the PPG.

Moreover, since the circuit board in the comparative example is comprised with the insulating layer only of PPG containing glass fiber, it has a high dielectric constant. However, in the case of a dielectric having a high permittivity, there is a problem in that it is difficult to access it as a substitute for a high frequency. That is, in the circuit board of the comparative example, since the dielectric constant of the glass fiber is high, the dielectric constant is broken in the high frequency band.

Accordingly, in the embodiment, the insulating layer is formed by using the RCC having a low dielectric constant, thereby reducing the thickness of the circuit board and providing a highly reliable circuit board in which signal loss is minimized even in a high frequency band.

On the other hand, as the second insulating layer 120 in the embodiment is made of RCC, the thickness of the printed circuit board can be remarkably reduced compared to the comparative example made of PPG. Accordingly, in the embodiment, the thickness of the printed circuit board can be reduced by at least 5 μm compared to the comparative example by using the RCC made of the low-dielectric constant material.

However, even if an RCC having a low dielectric constant of 2.7, which is 10% improved from the level of 3.0, which is the dielectric constant of PPG, is used, the thickness reduction rate is only 10% compared to the comparative example. Accordingly, in the embodiment, a cavity using a jig is formed in a portion on which a chip such as an electronic device is mounted to provide an optimal printed circuit board.

At this time, at least one of the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 represents the electrical wiring connecting the circuit components based on the circuit design as a wiring diagram, Electrical conductors can be reproduced in In addition, at least one of the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 may form a wiring for mounting electrical components and connecting them in a circuit, and the electrical connection of the components It can mechanically fix non-functional parts.

Circuit patterns may be disposed on the surfaces of the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 . For example, when the second insulating layer 120 is formed of a single layer, the circuit pattern 143 may be disposed on the upper surface of the second insulating layer 120 of the single layer.

Also, when the second insulating layer 120 includes a plurality of layers, the first circuit pattern 141 may be disposed on the upper surface of the first insulating layer 110 . In this case, a plurality of first circuit patterns 141 may be disposed on the upper surface of the first insulating layer 110 while being spaced apart from each other by a predetermined interval.

A second circuit pattern 142 may be disposed on a lower surface of the first insulating layer 110 . A plurality of second circuit patterns 142 may be disposed on the lower surface of the first insulating layer 110 while being spaced apart from each other by a predetermined interval.

Also, circuit patterns may be disposed on the surface of the second insulating layer 120 . For example, a plurality of third circuit patterns 143 may be disposed on the upper surface of the second-first insulating layer 121 to be spaced apart from each other by a predetermined interval. In addition, a plurality of fourth circuit patterns 144 may be disposed on the upper surface of the 2-2 insulating layer 122 to be spaced apart from each other by a predetermined interval. In addition, a plurality of fifth circuit patterns 145 may be disposed on the upper surface of the 2-3 th insulating layer 123 to be spaced apart from each other by a predetermined interval.

Also, circuit patterns may be disposed on the surface of the third insulating layer 130 . For example, when the third insulating layer 130 is formed of a single layer, the circuit pattern 146 may be disposed on the lower surface of the third insulating layer 130 of the single layer.

In addition, when the third insulating layer 130 is composed of a plurality of layers, a plurality of sixth circuit patterns 146 may be disposed on the lower surface of the 3-1 insulating layer 131 while being spaced apart from each other by a predetermined interval. In addition, a plurality of seventh circuit patterns 147 may be disposed on the lower surface of the 3-2 insulating layer 132 to be spaced apart from each other by a predetermined interval. In addition, a plurality of eighth circuit patterns 148 may be disposed on the lower surface of the 3 - 3 insulating layer 133 to be spaced apart from each other by a predetermined interval.

Meanwhile, the first to eighth circuit patterns 141 , 142 , 143 , 144 , 145 , 146 , 147 , and 148 as described above are wirings for transmitting electrical signals, and may be formed of a metal material having high electrical conductivity. To this end, the first to eighth circuit patterns 141 , 142 , 143 , 144 , 145 , 146 , 147 , and 148 are gold (Au), silver (Ag), platinum (Pt), titanium (Ti), and tin. It may be formed of at least one metal material selected from (Sn), copper (Cu), and zinc (Zn). In addition, the first to eighth circuit patterns 141 , 142 , 143 , 144 , 145 , 146 , 147 , and 148 have excellent bonding strength of gold (Au), silver (Ag), platinum (Pt), and titanium (Ti). , tin (Sn), copper (Cu), and zinc (Zn) may be formed of a paste or solder paste including at least one metal material selected from the group consisting of. Preferably, the first to eighth circuit patterns 141 , 142 , 143 , 144 , 145 , 146 , 147 , and 148 may be formed of copper (Cu), which has high electrical conductivity and is relatively inexpensive.

The first to eighth circuit patterns 141 , 142 , 143 , 144 , 145 , 146 , 147 , and 148 are an additive process, a subtractive process, which are typical printed circuit board manufacturing processes. ), Modified Semi Additive Process (MSAP), and Semi Additive Process (SAP) methods, and a detailed description thereof will be omitted here.

Meanwhile, the first circuit pattern 141 may include a pad 141a that is exposed through the cavity 160 while being disposed on the upper surface of the first insulating layer 110 . The pad 141a may be electrically connected to an electronic device (described later) mounted in the cavity 160 . For example, the pad 141a may be a wire bonding pad connected to an electronic device mounted in the cavity 160 through a wire. Alternatively, the pad 141a may be a flip-chip bonding pad directly connected to a terminal of an electronic device mounted in the cavity 160 . In this case, the pad 141a may include a first pad and a second pad disposed to be spaced apart from each other by a predetermined interval. This will be described in more detail below.

Meanwhile, the first to eighth circuit patterns 141 , 142 , 143 , 144 , 145 , 146 , 147 , and 148 are respectively connected to a via for interlayer conduction, a pattern for signal transfer, and an electronic device. It may include a pad that becomes

The first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 have vias V1 , V2 , V3 , V4 , V5 that electrically connect circuit patterns disposed on different layers to each other. V6, V7) may be arranged. The vias V1 , V2 , V3 , V4 , V5 , V6 , and V7 may be disposed to pass through at least one of the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 . can In addition, both ends of the vias V1 , V2 , V3 , V4 , V5 , V6 , and V7 are respectively connected to circuit patterns disposed on different insulating layers, and thus an electrical signal may be transmitted.

A first via V1 may be disposed on the first insulating layer 110 . The first via V1 may be disposed to penetrate the upper and lower surfaces of the first insulating layer 110 . The first via V1 electrically connects the first circuit pattern 141 disposed on the upper surface of the first insulating layer 110 and the second circuit pattern 142 disposed on the lower surface of the first insulating layer 110 . can connect

A plurality of vias may be disposed in the second insulating layer 120 . That is, the second via V2 may be disposed on the 2-1 insulating layer 121 . The second via V2 includes a first circuit pattern 141 disposed on the upper surface of the first insulating layer 110 and a third circuit pattern 143 disposed on the upper surface of the second-first insulating layer 121 . can be electrically connected.

Also, a third via V3 may be disposed in the 2-2nd insulating layer 122 . The third via V3 includes a fourth circuit pattern 144 disposed on the top surface of the 2-2 insulating layer 122 and a third circuit pattern 144 disposed on the top surface of the 2-1 insulating layer 121 ( 143) can be electrically connected.

Also, a fourth via V4 may be disposed in the 2-3 th insulating layer 123 . The fourth via V4 includes a fifth circuit pattern 145 disposed on the upper surface of the 2-3th insulating layer 123 and a fourth circuit pattern 145 disposed on the upper surface of the 2-2nd insulating layer 122 ( 144) can be electrically connected.

Also, when the second insulating layer 120 is configured as a single layer, only the second via V2 may be disposed in the second insulating layer 120 of the single layer.

A plurality of vias may be disposed in the third insulating layer 130 . That is, a fifth via V5 may be disposed in the 3-1 th insulating layer 131 . The fifth via V5 includes a second circuit pattern 142 disposed on a lower surface of the first insulating layer 110 and a sixth circuit pattern 146 disposed on a lower surface of the 3-1th insulating layer 131 . can be electrically connected.

In addition, a sixth via V6 may be disposed in the 3 - 2 insulating layer 132 . The sixth via V6 includes a seventh circuit pattern 147 disposed on the lower surface of the 3-2nd insulating layer 132 and a sixth circuit pattern 147 disposed on the lower surface of the 3-1th insulating layer 131 ( 146) can be electrically connected.

Also, a seventh via V7 may be disposed in the 3 - 3 insulating layer 133 . The seventh via V7 includes an eighth circuit pattern 148 disposed on the lower surface of the 3-3 insulating layer 133 and a seventh circuit pattern 148 disposed on the lower surface of the 3-2 insulating layer 132 ( 147) can be electrically connected.

Also, when the third insulating layer 130 is configured as a single layer, only the fifth via V5 may be disposed in the third insulating layer 130 of the single layer.

Meanwhile, the vias V1 , V2 , V3 , V4 , V5 , V6 , and V7 include only one insulating layer of the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 . may pass through, or alternatively may be disposed while passing through a plurality of insulating layers in common. Accordingly, the vias V1 , V2 , V3 , V4 , V5 , V6 , and V7 may connect circuit patterns disposed on the surface of an insulating layer that is at least two or more layers apart from each other, rather than adjacent insulating layers.

Meanwhile, the vias V1, V2, V3, V4, V5, V6, and V7 may be formed by filling the inside of a through hole (not shown) penetrating at least one insulating layer among the plurality of insulating layers with a conductive material. can

The through hole may be formed by any one of machining methods, including mechanical, laser, and chemical machining. When the through-hole is formed by machining, methods such as milling, drilling, and routing can be used, and when formed by laser processing, UV or CO ₂ laser method is used. In the case of being formed by chemical processing, at least one insulating layer among the plurality of insulating layers may be opened using chemicals including aminosilane, ketones, and the like.

On the other hand, the processing by the laser is a cutting method in which a part of the material is melted and evaporated by concentrating optical energy on the surface to take a desired shape, and complex formation by a computer program can be easily processed, and in other methods, cutting Even difficult composite materials can be machined.

In addition, the processing by the laser can have a cutting diameter of at least 0.005mm, and has a wide advantage in a range of possible thicknesses.

As the laser processing drill, it is preferable to use a YAG (Yttrium Aluminum Garnet) laser, a CO ₂ laser, or an ultraviolet (UV) laser. The YAG laser is a laser that can process both the copper foil layer and the insulating layer, and the CO ₂ laser is a laser that can process only the insulating layer.

When the through hole is formed, the vias V1 , V2 , V3 , V4 , V5 , V6 , and V7 may be formed by filling the inside of the through hole with a conductive material. The metal materials forming the vias V1, V2, V3, V4, V5, V6, and V7 are copper (Cu), silver (Ag), tin (Sn), gold (Au), nickel (Ni), and palladium ( Pd), and the conductive material filling is any one of electroless plating, electrolytic plating, screen printing, sputtering, evaporation, inkjetting, and dispensing. One or a combination thereof may be used.

Meanwhile, protective layers 151 and 152 may be disposed on the surface of the outermost insulating layer among the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 . For example, a first passivation layer 151 may be disposed on an upper surface of the topmost insulating layer among the plurality of insulating layers. For example, the first passivation layer 151 may be disposed on the upper surface of the 2-3th insulating layer 123 disposed on the uppermost portion of the second insulating layer 120 . In addition, a second passivation layer 152 may be disposed on a lower surface of the insulating layer disposed at the lowermost portion among the plurality of insulating layers. For example, a second passivation layer 152 may be disposed on a lower surface of the 3-3 insulating layer 133 disposed at the lowermost portion of the third insulating layer 130 .

In addition, when the second insulating layer 120 and the third insulating layer 130 are each composed of a single layer, the first protective layer 151 may be disposed on the upper surface of the second insulating layer 120 , The second passivation layer 152 may be disposed on the lower surface of the third insulating layer 130 .

The first passivation layer 151 and the second passivation layer 152 may each have an opening. For example, the first protective layer 151 may have an opening exposing the surface of the fifth circuit pattern to be exposed among the fifth circuit patterns 145 disposed on the upper surface of the 2-3th insulating layer 123 . have.

Also, the second passivation layer 152 may have an opening exposing the surface of the eighth circuit pattern to be exposed among the eighth circuit patterns 148 disposed on the lower surface of the 3-3 insulating layer 133 .

The first passivation layer 151 and the second passivation layer 152 may include an insulating material. The first passivation layer 151 and the second passivation layer 152 may include various materials that can be cured by heating after being applied to protect the surface of the circuit patterns. The first passivation layer 151 and the second passivation layer 152 may be a resist layer. For example, the first passivation layer 151 and the second passivation layer 152 may be a solder resist layer including an organic polymer material. For example, the first protective layer 151 and the second protective layer 152 may include an epoxy acrylate-based resin. In detail, the first protective layer 151 and the second protective layer 152 may include a resin, a curing agent, a photoinitiator, a pigment, a solvent, a filler, an additive, an acryl-based monomer, and the like. However, the embodiment is not limited thereto, and the first protective layer 151 and the second protective layer 152 may be any one of a photosolder resist layer, a cover-lay, and a polymer material. am.

The thickness of the first passivation layer 151 and the second passivation layer 152 may be 1 μm to 20 μm. The thickness of the first passivation layer 151 and the second passivation layer 152 may be 1 μm to 15 μm. For example, the thickness of the first passivation layer 151 and the second passivation layer 152 may be 5 μm to 20 μm. When the thickness of the first passivation layer 151 and the second passivation layer 152 is greater than 20 μm, the thickness of the printed circuit board 100 may increase. When the thickness of the first passivation layer 151 and the second passivation layer 152 is less than 1 μm, the reliability of circuit patterns included in the printed circuit board 100 may be deteriorated.

Meanwhile, a cavity 160 may be formed in the second insulating layer 120 . In this case, the cavity 160 may be formed in the second insulating layer 120 composed of a plurality of layers. In this case, the cavity 160 may be disposed to pass through at least one insulating layer among the second insulating layers 120 composed of the plurality of layers, and may be disposed to pass through at least another insulating layer.

That is, the general cavity is formed through the insulating layer. Accordingly, at the position where the cavity is to be formed, the insulating layer overlapping the cavity 160 in the horizontal direction does not exist. For example, the cavity in the comparative example is formed to penetrate from the upper surface to the lower surface of the second insulating layer 120 .

Alternatively, in the cavity in the embodiment, at least one insulating layer of the insulating layers vertically overlapping with the cavity 160 penetrates, but does not penetrate at least another insulating layer at a position where the cavity is disposed.

That is, the cavity 160 in the first embodiment is disposed in the second insulating layer 120 . That is, the cavity 160 is formed in the 2-1 th insulating layer 121 , the 2-2 th insulating layer 122 , and the 2-3 th insulating layer 123 . In addition, the cavity 160 in the second embodiment is formed in the second insulating layer 120 composed of one layer.

Hereinafter, the structure of the cavity formed in the second insulating layer 120 composed of a plurality of layers as in the first embodiment will be first described.

In this case, the cavity in the structure of the printed circuit board of the comparative example is disposed to penetrate through all of the 2-1 insulating layer 121 , the 2-2 insulating layer 122 , and the 2-3 th insulating layer 123 . Accordingly, in the printed circuit board of the comparative example, the upper surface of the first insulating layer in the region vertically overlapping with the cavity is exposed. That is, the second insulating layer (more specifically, the 2-1 insulating layer) does not exist on the upper surface of the first insulating layer vertically overlapping with the cavity in the printed circuit board of the comparative example.

In contrast, the cavity 160 in the printed circuit board 100 in the embodiment shown in FIGS. 1A and 2A penetrates through the 2-1 insulating layer 121 and the 2-2 insulating layer 122 . , may be disposed while not penetrating the 2-3th insulating layer 123 .

That is, the cavity 160 includes a first part P1 disposed in the 2-1 insulating layer 121 , a second part P2 disposed in the 2-2 insulating layer 122 , and a second-second part P2 disposed in the insulating layer 122 . 3 It may include a third part P3 disposed in the insulating layer 123 . Here, as the second insulating layer 122 in the embodiment has a three-layer structure, the cavity 160 is illustrated as being composed of the first to third parts P1, P2, and P3, but limited to this. it doesn't happen For example, when the second insulating layer 120 has a two-layer structure, the cavity 160 may include only the first and second parts. For example, when the second insulating layer 122 has a five-layer structure, the cavity 160 may include first to fifth parts. However, the cavity 160 in the embodiment is characterized in that the lowermost part has a groove shape rather than a through hole shape.

The first part P1 may be disposed in the second-first insulating layer 121 . In this case, the first part P1 may be a groove disposed in the second-first insulating layer 121 and forming a lower region of the cavity 160 .

The second part P2 may be disposed in the 2-2nd insulating layer 122 . The second part P2 is disposed in the 2-2nd insulating layer 122 and may be a through hole forming a central region of the cavity 160 .

The third part P3 may be disposed in the 2-3 th insulating layer 123 . The third part P3 may be disposed in the 2-3 th insulating layer 123 and may be a through hole forming an upper region of the cavity 160 .

That is, the cavity 160 may be formed of a combination of the first part P1 , the second part P2 , and the third part P3 . In this case, the thickness of the first part P1 may be smaller than the thickness of the second-first insulating layer 121 . Accordingly, the cavity 160 may be formed without penetrating the second-first insulating layer 121 .

In other words, the 2-1 th insulating layer 121 may include a first portion disposed on a region overlapping the cavity 160 in a vertical direction and a second portion excluding the first portion. In addition, the thicknesses H3 and H4 of the first portion may be different from the thickness H1 of the second portion.

Preferably, the thickness H1 of the second portion may correspond to the thickness of the second-first insulating layer 121 .

The thickness of the second portion may be 5 μm to 20 μm. For example, the thickness of the second part corresponds to the thickness of the 2-1 insulating layer 121 composed of one RCC layer, and thus may have a thickness of 5 μm to 20 μm.

The thicknesses H3 and H4 of the first part may be smaller than the thickness H1 of the second part. The thicknesses H3 and H4 of the first portion may be determined by the thickness H2 of the pad 141a. Preferably, the thicknesses H3 and H4 of the first portion may be smaller than the thickness H2 of the pad 141a.

Preferably, the thickness H2 of the pad 141a may be smaller than the thickness H1 of the second portion. For example, the thickness H2 of the pad 141a may be 5 μm to 10 μm.

In addition, the thicknesses H3 and H4 of the first portion may be smaller than the thickness H3 of the pad 141a. For example, the thicknesses H3 and H4 of the first portion may be 3 μm to 8 μm. Accordingly, the first portion of the second-first insulating layer 121 is disposed on the first insulating layer 110 . In this case, the first portion of the 2-1 th insulating layer 121 may expose a top surface of the pad 141a disposed on the first insulating layer 110 . Meanwhile, the thicknesses H3 and H4 of the first portion may be different for each region. For example, the thickness of the first portion may change from the outside to the inside. For example, the width of the first portion may gradually decrease from the outside to the inside.

That is, in the embodiment, in order to mount an electronic device, at least a portion of the second insulating layer 120 (the second insulating layer 2-1) passes through the second insulating layer 120 and does not form a cavity 160 . The cavity 160 is formed with the first portion of the layer 121 remaining on the first insulating layer 110 .

In this case, the remaining thicknesses H3 and H4 of a portion of the second insulating layer 120 are smaller than the thickness H2 of the pad 141a to be exposed on the cavity 160 . Accordingly, in the embodiment, the cavity 160 may be formed while maintaining the shape of the pad 141a without affecting the mounting of the electronic device on the pad 141a.

That is, in the prior art, in order to form cavities in the plurality of insulating layers as described above, the cavity formation process was performed in a state in which a protective layer or a stop layer was disposed on the first insulating layer. Accordingly, in the prior art, the cavity could be formed as much as a desired depth (a depth penetrating all of the second insulating layer). However, in the related art, after the cavity is formed, an etching process of removing the protective layer or the stop layer has to be performed. Accordingly, in the related art, a part of the pad disposed on the first insulating layer is also removed during the etching process of removing the protective layer or the stop layer, and thus, a problem may occur in the reliability of the pad. At this time, the thickness of the protective layer or the stop layer required during the sand blast or laser process is 3 μm to 10 μm. There were problems that were removed as much as they responded. In addition, as the cavity is conventionally formed using a laser or an etching process, the cavity has different upper and lower widths. For example, the conventional cavity has a trapezoidal shape in which the width gradually decreases from the upper side to the lower side.

Accordingly, in the embodiment, the cavity can be easily formed in a state in which the protective layer or the stop layer is not formed, and thus, the reliability problem that occurs during the process of removing the protective layer or the stop layer is solved. In addition, the cavity in the embodiment may have the same upper width and the same lower width. This is because the cavity is formed by using a jig (described later) having the same upper width and lower width.

Meanwhile, referring to FIGS. 1A and 2A , the cavity 160 includes an inner wall and bottom surfaces S1 and S2 .

The bottom surfaces S1 and S2 of the cavity 160 may have a predetermined surface roughness. At this time, in the embodiment, an additional process is not performed so that the bottom surfaces S1 and S2 of the cavity 160 have a predetermined surface roughness, but the second insulating layer 120 is formed in a state in which a jig is disposed. Accordingly, the bottom surfaces S1 and S2 may have a certain surface roughness.

In other words, the bottom surfaces S1 and S2 of the cavity 160 may refer to the top surface of the first portion of the second-first insulating layer 121 . In addition, the height of the upper surface of the first portion of the second-first insulating layer 121 is not constant, and may have a deviation depending on the position. Preferably, the height of the upper surface of the first portion of the second-first insulating layer 121 may change from the edge portion to the inner portion. Preferably, the height of the upper surface of the first portion of the second-first insulating layer 121 may decrease as the distance from the inner wall increases. In other words, the depth of the cavity 160 may vary depending on the location. For example, the depth of the cavity 160 may change from the outside to the inside. For example, the depth of the cavity 160 may gradually increase from the outside to the inside.

In this case, in the embodiment, since a rectangular jig is used to form the cavity 160 , the inner wall may be perpendicular to the main surface of the second insulating layer. Preferably, the cavity 160 may have a shape having an upper width and a lower width equal to each other.

In this case, the height of the first portion of the second insulating layer or the depth of the cavity 160 may be determined by the position of the pad 141a.

That is, the bottom surface of the cavity 160 may include a first region R1 and a second region R2 . The first region R1 may be an outer region of the cavity 160 . For example, the first region R1 may be an edge region of the cavity 160 . The second region R2 may be an inner region of the cavity 160 . For example, the second region R2 may be a central region of the cavity 160 .

In this case, the first region R1 and the second region R2 may be determined based on a region in which the plurality of pads 141a are disposed. For example, the first region R1 may be an outer region of the arrangement region of the plurality of pads 141a. For example, the second region R2 may be an inner region of a region in which the plurality of pads 141a are disposed. For example, the second region R2 may be a region between the plurality of pads 141a. Also, the first region R1 may be a region other than a region between the plurality of pads 141a. More specifically, the first region R1 may be an outer region of the bottom surface. In addition, the second region R2 may be a central region of the bottom surface. That is, the first region R1 may be formed to surround the periphery of the second region R2 .

Accordingly, the bottom surface of the cavity 160 includes a first bottom surface S1 corresponding to the first region R1 and a second bottom surface S2 corresponding to the second region R2. can do.

In addition, the first bottom surface S1 and the second bottom surface S2 may have different heights.

Preferably, the first bottom surface S1 and the second bottom surface S2 may have a height lower than that of the pad 141a, and may be disposed on an area in which the cavity is formed among the top surfaces of the first insulating layer.

As described above, the pad 141a may have a second height H2.

Also, the first bottom surface S1 may have a third height H3 that is smaller than the second height H2. In addition, the second bottom surface S2 may have a fourth height H4 smaller than the second height H2 and the third height H3 .

The third height H3 may have a level of 95% or less of the second height H2. In this case, the first bottom surface S1 may have different heights for each location. Accordingly, the third height H3 may mean an average height of the first floor surface S1 . Also, differently from this, the third height H3 may mean the largest height value among the heights of the first floor surface S1 for each position.

In this case, as described above, the first bottom surface S1 has different heights for each location. That is, the third height H3 of the first bottom surface S1 may have different values according to positions.

Preferably, the height of the first bottom surface S1 may decrease from the outside to the inside. For example, the first bottom surface S1 may have the greatest height at a portion closest to the inner wall. For example, the first bottom surface S1 may have the smallest height in a portion adjacent to the second bottom surface S2 .

Also, the second bottom surface S2 may have a height smaller than that of the first bottom surface S1 and may be positioned between the plurality of pads 141a in the cavity 160 .

In this case, the second bottom surface S2 may have a smaller height than the first bottom surface S1 . Furthermore, the second bottom surface S2 may have different heights depending on the location. That is, the fourth height H4 of the second bottom surface S2 may have different values depending on the location.

Preferably, the height of the second bottom surface S2 may decrease from the outside to the inside. For example, the second bottom surface S2 may have the greatest height at a portion adjacent to the inner side of the pad 141a (or a portion adjacent to the first bottom surface). Also, the second bottom surface S2 may have the smallest height in the central portion. That is, the cross-section of the second bottom surface S2 may have a V-shape in which the height gradually decreases from the outside to the inside. In addition, a cross-sectional view of the first bottom surface S1 may have a V-shape in which the height decreases from the outside to the inside.

That is, in the embodiment, the cavity 160 is formed using a jig. Accordingly, the cavity 160 in the above embodiment may have the same upper width and the same lower width.

In this case, the second insulating layer 120 in the embodiment may be formed in a state in which a jig is disposed on the region where the cavity 160 is to be formed. Accordingly, the second insulating layer 120 may be formed in the remaining area except for the area where the jig is disposed. That is, the second insulating layer 120 may be formed to open an area in which the jig is disposed.

Here, the pad 141a is disposed in the region where the cavity 160 is to be formed. In addition, the jig may be positioned on the pad 141a. At this time, the pad 141a has a certain height, and accordingly, in the region where the cavity 160 is to be formed, the jig does not come into contact with the upper surface of the first insulating layer 110, but rather the pad ( 141a) may be spaced apart from each other by a predetermined distance. In addition, the second insulating layer 120 may penetrate into a region between the first insulating layer and the jig in a state in which the jig is formed. At this time, when the second insulating layer 120 is laminated, the largest amount of resin penetrates into the relatively close first region R1, and thus the highest height at the outermost portion of the first bottom surface S1. can have In addition, when the second insulating layer 120 is laminated, the amount of penetration of the resin gradually decreases as the distance from the first region R1 is increased, and thus the lowest height in the central portion of the second bottom surface S2. can have

Meanwhile, as in the second embodiment, the cavity may be formed in the second insulating layer 120 composed of a single layer.

That is, the cavity 160 in the printed circuit board 100 according to the second embodiment may be formed without penetrating the second insulating layer 120 .

In other words, the second insulating layer 120 may include a first portion in which the cavity 160 is formed and a second portion excluding the first portion. In addition, the thicknesses H3 and H4 of the first portion may be different from the thickness H1 of the second portion.

Preferably, the thickness H1 of the second portion may correspond to the thickness of the second insulating layer 120 .

The thickness of the second portion may be 5 μm to 20 μm. For example, the thickness of the second part corresponds to the thickness of the second insulating layer 120 composed of one RCC layer, and thus may have a thickness of 5 μm to 20 μm.

The thicknesses H3 and H4 of the first part may be smaller than the thickness H1 of the second part. The thicknesses H3 and H4 of the first portion may be determined by the thickness H2 of the pad 141a. Preferably, the thicknesses H3 and H4 of the first portion may be smaller than the thickness H2 of the pad 141a.

Preferably, the thickness H2 of the pad 141a may be smaller than the thickness H1 of the second portion. For example, the thickness H2 of the pad 141a may be 5 μm to 10 μm.

In addition, the thicknesses H3 and H4 of the first portion may be smaller than the thickness H3 of the pad 141a. For example, the thicknesses H3 and H4 of the first portion may be 3 μm to 8 μm. Accordingly, the first portion of the second insulating layer 120 is disposed on the first insulating layer 110 . In this case, the first portion of the second insulating layer 120 may expose a top surface of the pad 141a disposed on the first insulating layer 110 . Meanwhile, the thicknesses H3 and H4 of the first portion may be different for each region. For example, the thickness of the first portion may change from the outside to the inside. For example, the width of the first portion may gradually decrease from the outside to the inside.

That is, in the embodiment, in order to mount an electronic device, at least a portion of the second insulating layer 120 is formed on the first insulating layer ( The cavity 160 is formed in a state remaining on the 110).

In this case, the remaining thicknesses H3 and H4 of a portion of the second insulating layer 120 are smaller than the thickness H2 of the pad 141a to be exposed on the cavity 160 . Accordingly, in the embodiment, the cavity 160 may be formed while maintaining the shape of the pad 141a without affecting the mounting of the electronic device on the pad 141a.

Also, referring to FIGS. 1B and 2B , the cavity 160 includes an inner wall and bottom surfaces S1 and S2 .

The bottom surfaces S1 and S2 of the cavity 160 may have a predetermined surface roughness. At this time, in the embodiment, an additional process is not performed so that the bottom surfaces S1 and S2 of the cavity 160 have a predetermined surface roughness, but the second insulating layer 120 is formed in a state in which a jig is disposed. Accordingly, the bottom surfaces S1 and S2 may have a certain surface roughness.

In other words, the bottom surfaces S1 and S2 of the cavity 160 may refer to the top surface of the first portion of the second insulating layer 120 . In addition, the height of the upper surface of the first portion of the second insulating layer 120 is not constant and may have a deviation depending on the position. Preferably, the height of the upper surface of the first portion of the second insulating layer 121 may vary from the edge portion to the inner portion. Preferably, the height of the upper surface of the first portion of the second insulating layer 120 may decrease as the distance from the inner wall increases. In other words, the depth of the cavity 160 may vary depending on the location. For example, the depth of the cavity 160 may change from the outside to the inside. For example, the depth of the cavity 160 may gradually increase from the outside to the inside.

In this case, in the embodiment, since a rectangular jig is used to form the cavity 160 , the inner wall may be perpendicular to the main surface of the second insulating layer. Preferably, the cavity 160 may have a shape having an upper width and a lower width equal to each other.

In this case, the height of the first portion of the second insulating layer or the depth of the cavity 160 may be determined by the position of the pad 141a.

That is, the bottom surface of the cavity 160 may include a first region R1 and a second region R2 . The first region R1 may be an outer region of the cavity 160 . For example, the first region R1 may be an edge region of the cavity 160 . The second region R2 may be an inner region of the cavity 160 . For example, the second region R2 may be a central region of the cavity 160 .

In this case, the first region R1 and the second region R2 may be determined based on a region in which the plurality of pads 141a are disposed. For example, the first region R1 may be an outer region of the arrangement region of the plurality of pads 141a. For example, the second region R2 may be an inner region of a region in which the plurality of pads 141a are disposed. For example, the second region R2 may be a region between the plurality of pads 141a. Also, the first region R1 may be a region other than a region between the plurality of pads 141a. More specifically, the first region R1 may be an outer region of the bottom surface. In addition, the second region R2 may be a central region of the bottom surface. That is, the first region R1 may be formed to surround the periphery of the second region R2 .

Accordingly, the bottom surface of the cavity 160 includes a first bottom surface S1 corresponding to the first region R1 and a second bottom surface S2 corresponding to the second region R2. can do.

In addition, the first bottom surface S1 and the second bottom surface S2 may have different heights.

Preferably, the first bottom surface S1 and the second bottom surface S2 may have a height lower than that of the pad 141a, and may be disposed on an area in which the cavity is formed among the top surfaces of the first insulating layer.

As described above, the pad 141a may have a second height H2.

Also, the first bottom surface S1 may have a third height H3 that is smaller than the second height H2. In addition, the second bottom surface S2 may have a fourth height H4 smaller than the second height H2 and the third height H3 .

The third height H3 may have a level of 95% or less of the second height H2. In this case, the first bottom surface S1 may have different heights for each location. Accordingly, the third height H3 may mean an average height of the first floor surface S1 . Also, differently from this, the third height H3 may mean the largest height value among the heights of the first floor surface S1 for each position.

In this case, as described above, the first bottom surface S1 has different heights for each location. That is, the third height H3 of the first bottom surface S1 may have different values according to positions.

Preferably, the height of the first bottom surface S1 may decrease from the outside to the inside. For example, the first bottom surface S1 may have the greatest height at a portion closest to the inner wall. For example, the first bottom surface S1 may have the smallest height in a portion adjacent to the second bottom surface S2 .

Also, the second bottom surface S2 may have a height smaller than that of the first bottom surface S1 and may be positioned between the plurality of pads 141a in the cavity 160 .

In this case, the second bottom surface S2 may have a smaller height than the first bottom surface S1 . Furthermore, the second bottom surface S2 may have different heights depending on the location. That is, the fourth height H4 of the second bottom surface S2 may have different values depending on the location.

Preferably, the height of the second bottom surface S2 may decrease from the outside to the inside. For example, the second bottom surface S2 may have the greatest height at a portion adjacent to the inner side of the pad 141a (or a portion adjacent to the first bottom surface). Also, the second bottom surface S2 may have the smallest height in the central portion. That is, the cross-section of the second bottom surface S2 may have a V-shape in which the height gradually decreases from the outside to the inside. In addition, a cross-sectional view of the first bottom surface S1 may have a V-shape in which the height decreases from the outside to the inside.

That is, in the printed circuit board 100 according to the first embodiment according to FIGS. 1A and 2A , the second insulating layer 120 is composed of a plurality of RCC layers, and the second insulating layer composed of the plurality of layers. A cavity 160 is formed in 120 . And, in the printed circuit board 100A according to the second embodiment according to FIGS. 1B and 2B , the second insulating layer 120 is composed of a single-layer RCC layer, and the single-layered second insulating layer 120 . In the cavity 160 is formed.

Hereinafter, a package substrate including the structure of the printed circuit board in the first embodiment will be mainly described.

3 is a view showing a package substrate according to the first embodiment.

Referring to FIG. 3 , the package substrate 200 in the embodiment includes the printed circuit board 100 shown in FIG. 1 and the electronic device 180 mounted in the cavity 160 of the printed circuit board 100 . do.

The printed circuit board 100 described with reference to FIGS. 1A, 1B, 2A and 2B may be used as a package board 200 for mounting the electronic device 180 .

At this time, since the printed circuit board 100 has already been described in detail above, a description thereof will be omitted.

The printed circuit board 100 includes a cavity 160 , and a pad 141a may be exposed in the cavity 160 . In this case, the second-first insulating layer 121 may be disposed in the cavity 160 except for the area where the pad 141a is formed. However, the height of the first portion of the 2-1 th insulating layer 121 is lower than the height of the pad 141a. Accordingly, the electronic device 180 may be stably mounted on the pad 141a without being affected by the first portion of the second insulating layer. In other words, if the height of the first portion of the 2-1 th insulating layer 121 is higher than the height of the pad 141a, the electronic device 180 is inclined on the pad 141a. may be mounted, and furthermore, a defect may occur in an electrical connection state with the pad 141a.

In this case, the electronic device 180 may be an electronic component disposed in the cavity 160 of the printed circuit board 100 , which may be divided into an active device and a passive device. In addition, the active element is an element that actively uses a non-linear portion, and the passive element refers to an element that does not use a non-linear characteristic even though both linear and non-linear characteristics exist. In addition, the passive element may include a transistor, an IC semiconductor chip, and the like, and the passive element may include a capacitor, a resistor, an inductor, and the like. The passive element is mounted on a general printed circuit board to increase a signal processing speed of a semiconductor chip, which is an active element, or to perform a filtering function.

Meanwhile, a connection unit 170 may be disposed on the pad 141a. A planar shape of the connection part 170 may be a quadrangle. The connection part 170 is disposed on the pad 141a and electrically connects the electronic device 180 and the pad 141a while fixing the electronic device 180 . To this end, the pad 141a may be formed of a conductive material. For example, the connection part 170 may be a solder ball. In the connection part 170 , a material of a different component may be contained in the solder. The solder may be composed of at least one of SnCu, SnPb, and SnAgCu. In addition, the heterogeneous material may include any one of Al, Sb, Bi, Cu, Ni, In, Pb, Ag, Sn, Zn, Ga, Cd, and Fe.

Meanwhile, the upper surface of the electronic device 180 may be positioned higher than the surface of the uppermost layer of the printed circuit board 100 . However, the embodiment is not limited thereto, and depending on the type of the electronic device 180 , the upper surface of the electronic device 180 may be disposed at the same height as the surface of the uppermost layer of the printed circuit board 100 . It could also be positioned lower otherwise.

4 is a view showing a package substrate according to a second embodiment.

Referring to FIG. 4 , the package substrate 200A according to the embodiment includes a printed circuit board 100 and an electronic device 180a mounted in a cavity 160 of the printed circuit board 100 .

In addition, the package substrate 200A is disposed in the cavity 160 and further includes a molding layer 190 covering the electronic device 180a.

The molding layer 190 may be selectively disposed in the cavity 160 to protect the electronic device 180a mounted in the cavity 160 .

The molding layer 190 may be formed of a resin for molding, for example, epoxy molding compound (EMC). However, the embodiment is not limited thereto, and the molding layer 190 may be formed of various other molding resins in addition to EMC.

The printed circuit board 100 may be used as a package board 200A for mounting the electronic device 180a.

The printed circuit board 100 includes a cavity 160 , and a pad 141a may be exposed in the cavity 160 . In this case, the second-first insulating layer 121 may be disposed in the cavity 160 except for the area where the pad 141a is formed. However, the height of the first portion of the 2-1 th insulating layer 121 is lower than the height of the pad 141a. Accordingly, the electronic device 180a may be stably mounted on the pad 141a without being affected by the first portion of the second-first insulating layer 121 . In other words, when the height of the first portion of the 2-1 th insulating layer 121 is higher than the height of the pad 141a, the electronic device 180a is inclined on the pad 141a. may be mounted, and furthermore, a defect may occur in an electrical connection state with the pad 141a.

In the embodiment, the molding layer 190 is disposed in contact with the inner wall and bottom surfaces S1 and S2 of the cavity 160 . In this case, the bottom surfaces S1 and S2 of the cavity 160 may have different heights according to their positions. In other words, the bottom surfaces S1 and S2 may not be flat and may have a predetermined inclination angle. In addition, the structure of the cavity 160 as described above can increase the surface area in contact with the molding layer 190 , thereby improving the bonding force between the molding layer 190 and the printed circuit board 100 . can do it

According to an embodiment, the printed circuit board includes a cavity. In this case, the cavity 160 has a non-penetrating structure rather than a penetrating structure through the second insulating layer 120 . In this case, the cavity 160 exposes the pad 141a disposed on the first insulating layer 110 . In addition, the bottom surface of the cavity 160 is positioned lower than the top surface of the pad 141a. Also, the cavity 160 may have the same upper width and the same lower width. Furthermore, the cavity 160 includes an inner wall and a bottom surface, and the height of the bottom surface may decrease from the outside to the inside. In other words, the depth of the cavity 160 may gradually increase from the outside to the inside.

Accordingly, in the embodiment, it is not necessary to form an additional layer to form the cavity 160 , and thus the number of processes can be reduced. In addition, in the embodiment, loss due to a change in thickness or shape of the pad 141a generated in the process of removing the additional layer may be solved, and thus product reliability may be improved.

According to an embodiment, the printed circuit board includes a cavity. In addition, the cavity of the printed circuit board has a non-penetrating structure rather than a structure penetrating the second insulating layer. In this case, the cavity exposes the pad disposed on the upper surface of the first insulating layer. In this case, the bottom surface of the cavity is positioned lower than the top surface of the pad. Accordingly, in the embodiment, it is not necessary to form an additional stop layer on the upper surface of the first insulating layer to form the cavity, and thus processes such as formation and removal of the stop layer can be omitted. have. In addition, in the embodiment, it is possible to solve a reliability problem due to a change in the thickness or shape of the pad that may occur in the process of removing the blocking layer in the comparative example, and thus product reliability can be improved.

In addition, the cavity of the printed circuit board in the embodiment includes a bottom surface and an inner wall. In this case, the bottom surface of the cavity may have different heights depending on the location. In other words, the bottom surface of the cavity may have a shape in which the height gradually decreases from the outside to the inside. Accordingly, when an additional molding layer is formed on the bottom surface of the cavity, a contact area with the molding layer may be increased, and thus product reliability may be improved.

In addition, the cavity of the printed circuit board in the embodiment is formed using a jig. And, the shape of the cavity may correspond to the shape of the jig. For example, the cavity may have an upper width and a lower width equal to each other. In this case, the inclination angle of the inner wall of the cavity in the comparative example may be perpendicular to the main surface.

In the above embodiment, the inclination angle of the inner wall can be reduced compared to the comparative example, and accordingly, on the assumption that the same element is disposed, the space required for cavity formation can be minimized compared to the comparative example, and thus the circuit integration can be improved. can In other words, by forming the inclination angle of the inner wall in the embodiment to be substantially vertical, more circuits can be formed in the same area compared to the comparative example, and thus the overall volume of the printed circuit board can be reduced.

Hereinafter, a method of manufacturing a printed circuit board according to an embodiment will be described with reference to the accompanying drawings.

5 to 9 are views showing the manufacturing method of the printed circuit board shown in FIG. 1B in order of process.

Referring to FIG. 5 , the first insulating layer 110 may be prepared, and first and second circuit patterns 141 and 142 may be formed on the surface of the first insulating layer 110 , and the first insulating layer 110 may be formed. A first via V1 passing through the layer 110 and electrically connecting the first and second circuit patterns 141 and 142 may be formed.

The first insulating layer 110 may be a prepreg. The prepreg (PPG) has good flowability and adhesion in a semi-cured state, and is used as an intermediate substrate for a fiber-reinforced composite material used as an adhesive layer and an insulating material layer. . A molded article is formed by laminating these prepregs and curing the resin by heating/pressing. That is, the prepreg refers to a material that is impregnated with resin (BT/Epoxy, FR4, FR5, etc.) into glass fiber and cured to B-stage.

That is, the first insulating layer 110 may be a thermosetting or thermoplastic polymer substrate, a ceramic substrate, an organic-inorganic composite material substrate, or a glass fiber-impregnated substrate. Alternatively, the polyimide-based resin may be included.

That is, the first insulating layer 110 is a plate on which an electric circuit capable of changing wiring is knitted, and includes all of a printed circuit board and an insulating substrate made of an insulating material capable of forming a conductor pattern on the surface of the insulating substrate. can do.

A metal layer (not shown) is laminated on the surface of the first insulating layer 110 . The metal layer may be formed by electroless plating a metal including copper on the first insulating layer 110 . In addition, unlike forming the metal layer by electroless plating on the first insulating layer 110 , copper clad laminate (CCL) may be used.

When the metal layer is formed by electroless plating, roughness is provided to the upper surface of the first insulating layer 110 so that plating can be performed smoothly. Then, by patterning the metal layer, first and second circuit patterns 141 and 142 are respectively formed on the upper and lower surfaces of the first insulating layer 110 . In this case, the first circuit pattern 141 may include the electronic devices 180 and 180a to be mounted on the first insulating layer 110 later and the pad 141a connected through the connection unit 170 .

As described above, the first and second circuit patterns 141 and 142 may be formed using an additive process, a subtractive process, a modified semi additive process (MSAP) and a conventional printed circuit board manufacturing process. It is possible by the SAP (Semi Additive Process) method, etc., and a detailed description is omitted here.

Next, referring to FIG. 6 , the jig 300 may be disposed in a region where the cavity 160 is to be formed among the upper regions of the first insulating layer 110 . The jig 300 may have a shape corresponding to the shape that the cavity 160 should have. For example, the jig 300 may have a rectangular shape.

The jig 300 may be formed of a material that can be easily separated from the second insulating layer 120 after lamination of the second insulating layer 120 later. For example, the jig 300 may be composed of at least one of a polymer, a ceramic, and a metal, and may have a property of being easily separated from the second insulating layer 120 .

Next, referring to FIG. 7 , a process of laminating the second insulating layer 120 and the third insulating layer 130 on the upper and lower portions of the first insulating layer 110 may be performed, respectively.

In this case, the second insulating layer 120 may have a single layer. Also, the third insulating layer 130 may have a single layer.

In addition, the second insulating layer 120 and the third insulating layer 130 may be formed of RCC.

Accordingly, the second insulating layer 120 and the third insulating layer 130 may have a thickness of 5 μm to 20 μm. For example, when the second insulating layer 120 has a plurality of layer structures, each of the plurality of layers may have a thickness of 5 μm to 20 μm. Also, when the second insulating layer 120 has a single layer, the thickness of the second insulating layer 120 of the single layer may be 5 μm to 20 μm.

In this case, the jig 300 may be disposed on the first insulating layer 110 and may be substantially non-contact with the first insulating layer 110 . That is, a pad 141a is disposed on the upper surface of the first insulating layer 110 , and accordingly, the jig 300 may be positioned on the pad 141a.

Accordingly, a space corresponding to the height of the pad 141a exists between the lower surface of the jig 300 and the upper surface of the first insulating layer 110 .

In addition, in the process of laminating the second insulating layer 120 , the second insulating layer 120 may penetrate into a space between the jig 300 and the first insulating layer 110 .

Accordingly, in the embodiment, when the cavity 160 is formed in the second insulating layer 120 disposed on the first insulating layer 110 , the cavity 160 forms the second insulating layer 120 . It may have a non-penetrating structure instead of a penetrating structure. That is, a cavity in a general printed circuit board includes an inner wall formed on the second insulating layer 120 and a bottom surface corresponding to the upper surface of the first insulating layer 110 . Further, in the cavity 160 in the embodiment, both the inner wall and the bottom surface may be formed in the second insulating layer 120 .

Meanwhile, in the above, after forming the jig 300 , a process of laminating the second insulating layer 120 was performed. However, unlike this, the jig 300 may include an RCC layer constituting the second insulating layer 120 . That is, in the semi-cured state of the RCC layer, by bonding it to the jig 300 and laminating the jig 300 to which the RCC layer is bonded on the first insulating layer 110, the cavity ( The second insulating layer 120 including 160 may be formed.

Next, referring to FIG. 8 , a process of removing the jig 300 in a state in which the second insulating layer 120 is stacked is performed to form a cavity 160 in the second insulating layer 120 . can

The cavity 160 formed in this way includes an inner wall and bottom surfaces S1 and S2.

The bottom surfaces S1 and S2 of the cavity 160 may have a predetermined surface roughness. At this time, in the embodiment, an additional process is not performed so that the bottom surfaces S1 and S2 of the cavity 160 have a predetermined surface roughness, but the second insulating layer 120 is formed in a state in which a jig is disposed. Accordingly, the bottom surfaces S1 and S2 may have a certain surface roughness.

In other words, the bottom surfaces S1 and S2 of the cavity 160 may refer to the top surface of the first portion of the second insulating layer 120 . In addition, the height of the upper surface of the first portion of the second insulating layer 120 is not constant and may have a deviation depending on the position. Preferably, the height of the upper surface of the first portion of the second insulating layer 121 may vary from the edge portion to the inner portion. Preferably, the height of the upper surface of the first portion of the second insulating layer 120 may decrease as the distance from the inner wall increases. In other words, the depth of the cavity 160 may vary depending on the location. For example, the depth of the cavity 160 may change from the outside to the inside. For example, the depth of the cavity 160 may gradually increase from the outside to the inside.

In this case, in the embodiment, since a rectangular jig is used to form the cavity 160 , the inner wall may be perpendicular to the main surface of the second insulating layer. Preferably, the cavity 160 may have a shape having an upper width and a lower width equal to each other.

In this case, the height of the first portion of the second insulating layer or the depth of the cavity 160 may be determined by the position of the pad 141a.

That is, the bottom surface of the cavity 160 may include a first region R1 and a second region R2 . The first region R1 may be an outer region of the cavity 160 . For example, the first region R1 may be an edge region of the cavity 160 . The second region R2 may be an inner region of the cavity 160 . For example, the second region R2 may be a central region of the cavity 160 .

In this case, the first region R1 and the second region R2 may be determined based on a region in which the plurality of pads 141a are disposed. For example, the first region R1 may be an outer region of the arrangement region of the plurality of pads 141a. For example, the second region R2 may be an inner region of a region in which the plurality of pads 141a are disposed. For example, the second region R2 may be a region between the plurality of pads 141a. Also, the first region R1 may be a region other than a region between the plurality of pads 141a. More specifically, the first region R1 may be an outer region of the bottom surface. In addition, the second region R2 may be a central region of the bottom surface. That is, the first region R1 may be formed to surround the periphery of the second region R2 .

Accordingly, the bottom surface of the cavity 160 includes a first bottom surface S1 corresponding to the first region R1 and a second bottom surface S2 corresponding to the second region R2. can do.

In addition, the first bottom surface S1 and the second bottom surface S2 may have different heights.

Preferably, the first bottom surface S1 and the second bottom surface S2 may have a height lower than that of the pad 141a, and may be disposed on an area in which the cavity is formed among the top surfaces of the first insulating layer.

As described above, the pad 141a may have a second height H2.

Also, the first bottom surface S1 may have a third height H3 that is smaller than the second height H2. In addition, the second bottom surface S2 may have a fourth height H4 smaller than the second height H2 and the third height H3 .

The third height H3 may have a level of 95% or less of the second height H2. In this case, the first bottom surface S1 may have different heights for each location. Accordingly, the third height H3 may mean an average height of the first floor surface S1 . Also, differently from this, the third height H3 may mean the largest height value among the heights of the first floor surface S1 for each position.

In this case, as described above, the first bottom surface S1 has different heights for each location. That is, the third height H3 of the first bottom surface S1 may have different values according to positions.

Preferably, the height of the first bottom surface S1 may decrease from the outside to the inside. For example, the first bottom surface S1 may have the greatest height at a portion closest to the inner wall. For example, the first bottom surface S1 may have the smallest height in a portion adjacent to the second bottom surface S2 .

Also, the second bottom surface S2 may have a height smaller than that of the first bottom surface S1 and may be positioned between the plurality of pads 141a in the cavity 160 .

In this case, the second bottom surface S2 may have a smaller height than the first bottom surface S1 . Furthermore, the second bottom surface S2 may have different heights depending on the location. That is, the fourth height H4 of the second bottom surface S2 may have different values depending on the location.

Preferably, the height of the second bottom surface S2 may decrease from the outside to the inside. For example, the second bottom surface S2 may have the greatest height at a portion adjacent to the inner side of the pad 141a (or a portion adjacent to the first bottom surface). Also, the second bottom surface S2 may have the smallest height in the central portion. That is, the cross-section of the second bottom surface S2 may have a V-shape in which the height gradually decreases from the outside to the inside. In addition, a cross-sectional view of the first bottom surface S1 may have a V-shape in which the height decreases from the outside to the inside.

Next, referring to FIG. 9 , in the embodiment, a process of forming a circuit pattern on the surface of the second insulating layer 120 may be performed.

In addition, in an embodiment, a process of forming a circuit pattern on the surface of the third insulating layer 130 may be performed.

In addition, a process of forming vias for electrically connecting circuit patterns disposed on different layers to each other may be performed in the second insulating layer 120 and the third insulating layer 130 .

In addition, when the circuit pattern and vias are formed, protective layers 151 and 152 are formed on the upper surface of the second insulating layer 120 and the lower surface of the third insulating layer 130 .

The first passivation layer 151 and the second passivation layer 152 may each have an opening. For example, the first protective layer 151 may have an opening exposing the surface of the circuit pattern to be exposed among the circuit patterns disposed on the upper surface of the second insulating layer 120 .

Also, the second protective layer 152 may have an opening exposing the surface of the circuit pattern to be exposed among the circuit patterns disposed on the lower surface of the third insulating layer 130 .

The first passivation layer 151 and the second passivation layer 152 may include an insulating material. The first passivation layer 151 and the second passivation layer 152 may include various materials that can be cured by heating after being applied to protect the surface of the circuit patterns. The first passivation layer 151 and the second passivation layer 152 may be a resist layer. For example, the first passivation layer 151 and the second passivation layer 152 may be a solder resist layer including an organic polymer material. For example, the first protective layer 151 and the second protective layer 152 may include an epoxy acrylate-based resin. In detail, the first protective layer 151 and the second protective layer 152 may include a resin, a curing agent, a photoinitiator, a pigment, a solvent, a filler, an additive, an acryl-based monomer, and the like. However, the embodiment is not limited thereto, and the first protective layer 151 and the second protective layer 152 may be any one of a photosolder resist layer, a cover-lay, and a polymer material. am.

The thickness of the first passivation layer 151 and the second passivation layer 152 may be 1 μm to 20 μm. The thickness of the first passivation layer 151 and the second passivation layer 152 may be 1 μm to 15 μm. For example, the thickness of the first passivation layer 151 and the second passivation layer 152 may be 5 μm to 20 μm. When the thickness of the first passivation layer 151 and the second passivation layer 152 is greater than 20 μm, the thickness of the printed circuit board 100 may increase. When the thickness of the first passivation layer 151 and the second passivation layer 152 is less than 1 μm, the reliability of circuit patterns included in the printed circuit board 100 may be deteriorated.

Meanwhile, in the embodiment, the cavity 160A may be formed by using the jig 300 in a manner different from that of the first and second embodiments.

10 is a view showing a printed circuit board 100B according to the third embodiment.

Referring to FIG. 10 , the printed circuit board according to the third embodiment includes the first insulating layer 110 , the second insulating layer 120 , and the third insulating layer 130 as described above. In addition, a first passivation layer 151 is disposed on an upper surface of the second insulating layer 120 , and a second passivation layer 152 is disposed on a lower surface of the third insulating layer 130 .

As in the third embodiment, the cavity 160A may be formed in the second insulating layer 120 composed of a single layer. However, the cavity 160A may be formed in the second insulating layer 120 composed of a plurality of layers.

Meanwhile, the cavity 160A in the printed circuit board 100B according to the third embodiment may be formed without penetrating the second insulating layer 120 .

In other words, the second insulating layer 120 may include a first portion in which the cavity 160A is formed and a second portion excluding the first portion. In addition, the thickness H3 of the first portion may be different from the thickness H1 of the second portion.

Preferably, the thickness H1 of the second portion may correspond to the thickness of the second insulating layer 120 .

The thickness of the second portion may be 5 μm to 20 μm. For example, the thickness of the second portion corresponds to the thickness of the second insulating layer 120 composed of one layer of RCC, and thus may have a thickness of 5 μm to 20 μm.

A thickness H3 of the first portion may be smaller than a thickness H1 of the second portion. The thickness H3 of the first portion may be determined by the thickness H2 of the pad 141a. Preferably, the thickness H3 of the first portion may be smaller than the thickness H2 of the pad 141a.

Preferably, the thickness H2 of the pad 141a may be smaller than the thickness H1 of the second portion. For example, the thickness H2 of the pad 141a may be 5 μm to 10 μm.

In addition, the thickness H3 of the first portion may be smaller than the thickness H2 of the pad 141a. For example, the thickness H3 of the first portion may be 3 μm to 8 μm. Accordingly, the first portion of the second insulating layer 120 is disposed on the first insulating layer 110 . In this case, the first portion of the second insulating layer 120 may expose a top surface of the pad 141a disposed on the first insulating layer 110 .

That is, in the embodiment, in order to mount an electronic device, at least a portion of the second insulating layer 120 is formed on the first insulating layer ( The cavity 160 is formed in a state remaining on the 110).

In this case, the thickness H3 of the remaining portion of the second insulating layer 120 is smaller than the thickness H2 of the pad 141a to be exposed on the cavity 160 . Accordingly, in the embodiment, the cavity 160 may be formed while maintaining the shape of the pad 141a without affecting the mounting of the electronic device on the pad 141a.

The cavity 160A includes an inner wall S1 , a bottom surface S2 , and an edge surface S3 between the inner wall S1 and the bottom surface S2 .

The inner wall S1 may be perpendicular to an upper surface or a lower surface of the second insulating layer 120 . Also, the bottom surface S2 may be parallel to an upper surface or a lower surface of the second insulating layer 120 .

Also, the edge surface S3 may connect between the inner wall S1 and the bottom surface S2. In this case, the edge surface S3 may have a curved surface that is not a right angle. That is, in the embodiment, the cavity 160A may be formed by performing an additional process in a state in which the groove G of a predetermined depth is formed in the second insulating layer 120 using the jig 300 . In this case, the additional process may include, for example, a desmear process.

Here, in the case of performing the desmear process, chemical etching is performed in the desmear process, so that it is necessary to set a compensation area between the jig 300 and the cavity 160A. For example, the groove G formed through the jig 300 may have an area smaller than that of the cavity 160A.

At this time, in the case of performing the desmear process, penetration of the etchant into the corner portion is relatively more difficult than that of the inner wall S1 of the cavity 160A, and accordingly, the corner surface S3 of the cavity 160A has a curved surface. can

In addition, the bottom surface S2 of the cavity 160A may have a certain roughness according to the desmear process. In addition, the roughness of the bottom surface S2 may improve bonding strength with the molding layer later. For example, the bottom surface S2 may have a predetermined curve according to the desmear process.

The bottom surface S2 may have a third height H3. That is, the pad 141a may have a second height H2. In addition, the bottom surface S2 may have a third height H3 smaller than the second height H2 .

The third height H3 of the bottom surface S2 may have a level in the range of 30% to 95% of the second height H2.

That is, in the printed circuit board 100B in the third embodiment according to FIG. 10 , the second insulating layer 120 is composed of a single-layer RCC layer, and a cavity ( 160A) is formed. At this time, the cavity 160A may be formed through a desmear process that is performed after the pressing process of the jig 300, and accordingly, the inner wall S1, the bottom surface S2, and the curved edge surface S3. can do.

11 to 14 are views showing the manufacturing method of the printed circuit board shown in FIG. 10 in order of process.

Referring to FIG. 11 , the first insulating layer 110 may be prepared, and first and second circuit patterns 141 and 142 may be formed on the surface of the first insulating layer 110 , and the first insulating layer 110 may be formed. A first via V1 passing through the layer 110 and electrically connecting the first and second circuit patterns 141 and 142 may be formed.

The first insulating layer 110 may be a prepreg. The prepreg (PPG) has good flowability and adhesion in a semi-cured state, and is used as an intermediate substrate for a fiber-reinforced composite material used as an adhesive layer and an insulating material layer. . A molded article is formed by laminating these prepregs and curing the resin by heating/pressing. That is, the prepreg refers to a material that is impregnated with resin (BT/Epoxy, FR4, FR5, etc.) into glass fiber and cured to B-stage.

That is, the first insulating layer 110 may be a thermosetting or thermoplastic polymer substrate, a ceramic substrate, an organic-inorganic composite material substrate, or a glass fiber-impregnated substrate. Alternatively, the polyimide-based resin may be included.

That is, the first insulating layer 110 is a plate on which an electric circuit capable of changing wiring is knitted, and includes all of a printed circuit board and an insulating substrate made of an insulating material capable of forming a conductor pattern on the surface of the insulating substrate. can do.

A metal layer (not shown) is laminated on the surface of the first insulating layer 110 . The metal layer may be formed by electroless plating a metal including copper on the first insulating layer 110 . In addition, unlike forming the metal layer by electroless plating on the first insulating layer 110 , copper clad laminate (CCL) may be used.

When the metal layer is formed by electroless plating, roughness is provided to the upper surface of the first insulating layer 110 so that plating can be performed smoothly. Then, by patterning the metal layer, first and second circuit patterns 141 and 142 are respectively formed on the upper and lower surfaces of the first insulating layer 110 . In this case, the first circuit pattern 141 may include the electronic devices 180 and 180a to be mounted on the first insulating layer 110 later and the pad 141a connected through the connection unit 170 .

As described above, the first and second circuit patterns 141 and 142 may be formed using an additive process, a subtractive process, a modified semi additive process (MSAP) and a conventional printed circuit board manufacturing process. It is possible by the SAP (Semi Additive Process) method, etc., and a detailed description is omitted here.

When the first insulating layer 110 is formed, a second insulating layer 120 is laminated on an upper surface of the first insulating layer 110 , and a third insulating layer ( 130) may be laminated. In addition, a process of forming circuit patterns on the upper surface of the second insulating layer 120 and the lower surface of the third insulating layer 130 may be performed, respectively. In addition, a process of forming vias in the inside of the second insulating layer 120 and the inside of the third insulating layer 130 may be performed, respectively.

Accordingly, the second insulating layer 120 and the third insulating layer 130 may have a thickness of 5 μm to 20 μm. For example, when the second insulating layer 120 has a plurality of layer structures, each of the plurality of layers may have a thickness of 5 μm to 20 μm. Also, when the second insulating layer 120 has a single layer, the thickness of the second insulating layer 120 of the single layer may be 5 μm to 20 μm.

Meanwhile, in a state in which the second insulating layer 120 and the third insulating layer 130 are disposed on the first insulating layer 110 as described above, the second insulating layer 120 using a jig 300 is used. of the press process can be performed.

That is, the jig 300 may be positioned on the second insulating layer 120 , and thus the pressing process of the jig 300 may be performed.

Accordingly, as shown in FIG. 12 , a groove G having a predetermined depth may be formed in the second insulating layer 120 . In this case, the area of the groove G may be smaller than the area of the cavity 160A formed in the second insulating layer 120 .

The jig 300 may be formed of a material that can be easily separated from the second insulating layer 120 after lamination of the second insulating layer 120 later. For example, the jig 300 may be composed of at least one of a polymer, a ceramic, and a metal, and may have a property of being easily separated from the second insulating layer 120 .

Next, as shown in FIG. 13 , a cavity 160A may be formed in the second insulating layer 120 by further processing the formed groove G. Referring to FIG. The additional process may include a desmear process, but is not limited thereto.

That is, the cavity 160A formed by performing a pressing process and a desmear process using a jig may be formed without penetrating the second insulating layer 120 .

In other words, the second insulating layer 120 may include a first portion in which the cavity 160A is formed and a second portion excluding the first portion. In addition, the thickness H3 of the first portion may be different from the thickness H1 of the second portion.

Preferably, the thickness H1 of the second portion may correspond to the thickness of the second insulating layer 120 . The thickness of the second portion may be 5 μm to 20 μm. For example, the thickness of the second portion corresponds to the thickness of the second insulating layer 120 composed of one layer of RCC, and thus may have a thickness of 5 μm to 20 μm.

A thickness H3 of the first portion may be smaller than a thickness H1 of the second portion. The thickness H3 of the first portion may be determined by the thickness H2 of the pad 141a. Preferably, the thickness H3 of the first portion may be smaller than the thickness H2 of the pad 141a.

Preferably, the thickness H2 of the pad 141a may be smaller than the thickness H1 of the second portion. For example, the thickness H2 of the pad 141a may be 5 μm to 10 μm.

In addition, the thickness H3 of the first portion may be smaller than the thickness H2 of the pad 141a. For example, the thickness H3 of the first portion may be 3 μm to 8 μm. Accordingly, the first portion of the second insulating layer 120 is disposed on the first insulating layer 110 . In this case, the first portion of the second insulating layer 120 may expose a top surface of the pad 141a disposed on the first insulating layer 110 .

In this case, the thickness H3 of the remaining portion of the second insulating layer 120 is smaller than the thickness H2 of the pad 141a to be exposed on the cavity 160 . Accordingly, in the embodiment, the cavity 160 may be formed while maintaining the shape of the pad 141a without affecting the mounting of the electronic device on the pad 141a.

The cavity 160A includes an inner wall S1 , a bottom surface S2 , and an edge surface S3 between the inner wall S1 and the bottom surface S2 .

The inner wall S1 may be perpendicular to an upper surface or a lower surface of the second insulating layer 120 . Also, the bottom surface S2 may be parallel to an upper surface or a lower surface of the second insulating layer 120 .

Also, the edge surface S3 may connect between the inner wall S1 and the bottom surface S2. In this case, the edge surface S3 may have a curved surface that is not a right angle. That is, in the embodiment, the cavity 160A may be formed by performing an additional process in a state in which the groove G of a predetermined depth is formed in the second insulating layer 120 using the jig 300 . In this case, the additional process may include, for example, a desmear process.

Here, in the case of performing the desmear process, chemical etching is performed in the desmear process, so that it is necessary to set a compensation area between the jig 300 and the cavity 160A. For example, the groove G formed through the jig 300 may have an area smaller than that of the cavity 160A.

At this time, in the case of performing the desmear process, penetration of the etchant into the corner portion is relatively more difficult than that of the inner wall S1 of the cavity 160A, and accordingly, the corner surface S3 of the cavity 160A has a curved surface. can

In addition, the bottom surface S2 of the cavity 160A may have a certain roughness according to the desmear process. In addition, the roughness of the bottom surface S2 may improve bonding strength with the molding layer later. For example, the bottom surface S2 may have a predetermined curve according to the desmear process.

The bottom surface S2 may have a third height H3. That is, the pad 141a may have a second height H2. In addition, the bottom surface S2 may have a third height H3 smaller than the second height H2 .

The third height H3 of the bottom surface S2 may have a level in the range of 30% to 95% of the second height H2.

Next, as shown in FIG. 14 , when the cavity 160A is formed, protective layers 151 and 152 are formed on the upper surface of the second insulating layer 120 and the lower surface of the third insulating layer 130 . .

The first passivation layer 151 and the second passivation layer 152 may each have an opening. For example, the first protective layer 151 may have an opening exposing the surface of the circuit pattern to be exposed among the circuit patterns disposed on the upper surface of the second insulating layer 120 .

Also, the second protective layer 152 may have an opening exposing the surface of the circuit pattern to be exposed among the circuit patterns disposed on the lower surface of the third insulating layer 130 .

The first passivation layer 151 and the second passivation layer 152 may include an insulating material. The first passivation layer 151 and the second passivation layer 152 may include various materials that can be cured by heating after being applied to protect the surface of the circuit patterns. The first passivation layer 151 and the second passivation layer 152 may be a resist layer. For example, the first passivation layer 151 and the second passivation layer 152 may be a solder resist layer including an organic polymer material. For example, the first protective layer 151 and the second protective layer 152 may include an epoxy acrylate-based resin. In detail, the first protective layer 151 and the second protective layer 152 may include a resin, a curing agent, a photoinitiator, a pigment, a solvent, a filler, an additive, an acryl-based monomer, and the like. However, the embodiment is not limited thereto, and the first protective layer 151 and the second protective layer 152 may be any one of a photosolder resist layer, a cover-lay, and a polymer material. am.

The thickness of the first passivation layer 151 and the second passivation layer 152 may be 1 μm to 20 μm. The thickness of the first passivation layer 151 and the second passivation layer 152 may be 1 μm to 15 μm. For example, the thickness of the first passivation layer 151 and the second passivation layer 152 may be 5 μm to 20 μm. When the thickness of the first passivation layer 151 and the second passivation layer 152 is greater than 20 μm, the thickness of the printed circuit board 100 may increase. When the thickness of the first passivation layer 151 and the second passivation layer 152 is less than 1 μm, the reliability of circuit patterns included in the printed circuit board 100 may be deteriorated.

In addition, in the embodiment, a combination shape of the second embodiment and the third embodiment is also possible. For example, the desmear process may be additionally performed on the cavity according to the second embodiment, so that the cavity may include a curved edge surface between the inner wall and the bottom surface.

According to an embodiment, the printed circuit board includes a cavity. In addition, the cavity of the printed circuit board has a non-penetrating structure rather than a structure penetrating the second insulating layer. In this case, the cavity exposes the pad disposed on the upper surface of the first insulating layer. In this case, the bottom surface of the cavity is positioned lower than the top surface of the pad. Accordingly, in the embodiment, it is not necessary to form an additional stop layer on the upper surface of the first insulating layer to form the cavity, and thus processes such as formation and removal of the stop layer can be omitted. have. In addition, in the embodiment, it is possible to solve a reliability problem due to a change in the thickness or shape of the pad that may occur in the process of removing the blocking layer in the comparative example, and thus product reliability can be improved.

In addition, the cavity of the printed circuit board in the embodiment includes a bottom surface and an inner wall. In this case, the bottom surface of the cavity may have different heights depending on the location. In other words, the bottom surface of the cavity may have a shape in which the height gradually decreases from the outside to the inside. Accordingly, when an additional molding layer is formed on the bottom surface of the cavity, a contact area with the molding layer may be increased, and thus product reliability may be improved.

In addition, the cavity of the printed circuit board in the embodiment is formed using a jig. And, the shape of the cavity may correspond to the shape of the jig. For example, the cavity may have an upper width and a lower width equal to each other. In this case, the inclination angle of the inner wall of the cavity in the comparative example may be perpendicular to the main surface.

In the above embodiment, the inclination angle of the inner wall can be reduced compared to the comparative example, and accordingly, on the assumption that the same element is disposed, the space required for cavity formation can be minimized compared to the comparative example, and thus the circuit integration can be improved. can In other words, by forming the inclination angle of the inner wall in the embodiment to be substantially vertical, more circuits can be formed in the same area compared to the comparative example, and thus the overall volume of the printed circuit board can be reduced.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments.

In the above, the embodiment has been mainly described, but this is only an example and not limiting the embodiment, and those of ordinary skill in the art to which the embodiment belongs may have several examples not illustrated above in the range that does not deviate from the essential characteristics of the embodiment. It can be seen that variations and applications of branches are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the embodiments set forth in the appended claims.

Claims (18)

a first insulating layer;
a second insulating layer disposed on the first insulating layer and including a cavity;
a plurality of pads disposed on the first insulating layer and whose upper surface is exposed through the cavity;
The cavity of the second insulating layer,
a bottom surface positioned higher than the top surface of the first insulating layer;
Including an inner wall extending from the bottom surface,
The inner wall is perpendicular to the upper surface or the lower surface of the second insulating layer,
The bottom surface of the cavity is
a first bottom surface positioned lower than the top surface of the pad and positioned outside the arrangement area of the plurality of pads;
and a second bottom surface positioned lower than the upper surface of the pad and positioned inside the arrangement area of the plurality of pads,
The height of the first floor surface,
different from the height of the second bottom surface
printed circuit board. According to claim 1,
The height of the first floor surface is greater than the height of the second floor surface
printed circuit board. According to claim 1,
At least one of the first bottom surface and the second bottom surface has a height that decreases from the outside to the inside.
printed circuit board. 4. The method of claim 3,
The combination shape of the first bottom surface and the second bottom surface has a V-shape.
printed circuit board. According to claim 1,
The upper width of the cavity is equal to the lower width of the cavity
printed circuit board. According to claim 1,
The thickness of the second insulating layer has a range of 5um to 20um
printed circuit board. 7. The method of claim 6,
The second insulating layer comprises RCC (Resin Coated Copper)
printed circuit board. According to claim 1,
The cavity includes a corner surface between the inner wall and the bottom surface,
The edge surface has a curved surface
printed circuit board. a first insulating layer;
a second insulating layer disposed on the first insulating layer and including a cavity;
a plurality of pads disposed on the first insulating layer and having an upper surface exposed through the cavity;
a connection portion disposed on the plurality of pads; and
It includes an electronic device disposed on the connection portion,
The cavity of the second insulating layer,
a bottom surface positioned higher than the top surface of the first insulating layer;
an inner wall extending from the bottom surface;
Comprising a corner surface between the inner wall and the bottom surface,
The inner wall is perpendicular to the upper surface or the lower surface of the second insulating layer,
The edge surface has a curved surface
package board. 10. The method of claim 9,
The bottom surface of the cavity is
a first bottom surface positioned lower than the top surface of the pad and positioned outside the arrangement area of the plurality of pads;
and a second bottom surface positioned lower than the upper surface of the pad and located inside the arrangement area of the plurality of pads;
The height of the first floor surface,
different from the height of the second bottom surface
package board. 11. The method of claim 10,
The height of the first floor surface is greater than the height of the second floor surface,
At least one of the first bottom surface and the second bottom surface has a height that decreases from the outside to the inside.
package board. 12. The method of claim 11,
The combination shape of the first bottom surface and the second bottom surface has a V-shape.
package board. 12. The method of claim 11,
The upper width of the cavity is equal to the lower width of the cavity
package board. 11. The method of claim 10,
The second insulating layer includes resin coated copper (RCC) and has a thickness in the range of 5um to 20um.
package board. 11. The method of claim 10,
and a molding layer disposed in the cavity and covering at least a portion of the electronic device.
package board. Prepare a first insulating layer,
forming a plurality of pads on the upper surface of the first insulating layer;
disposing a jig on the plurality of pads of the first insulating layer;
using the jig to form a second insulating layer in an upper region of the first insulating layer other than the region where the jig is disposed;
Separating the jig from the second insulating layer, comprising forming a cavity in an area where the jig is disposed,
The second insulating layer includes RCC (Resin Coated Copper),
The cavity of the second insulating layer,
a bottom surface positioned higher than the top surface of the first insulating layer;
Including an inner wall extending from the bottom surface,
The inner wall is perpendicular to the upper surface or the lower surface of the second insulating layer,
The bottom surface of the cavity is
a first bottom surface positioned lower than the upper surface of the pad and positioned outside the arrangement area of the plurality of pads;
and a second bottom surface positioned lower than the upper surface of the pad and located inside the arrangement area of the plurality of pads,
The height of the first floor surface,
greater than the height of the second bottom surface
A method for manufacturing a printed circuit board. 17. The method of claim 16,
At least one of the first bottom surface and the second bottom surface decreases in height from the outside to the inside,
The combination shape of the first bottom surface and the second bottom surface has a V-shape,
The upper width of the cavity is equal to the lower width of the cavity
A method for manufacturing a printed circuit board. 17. The method of claim 16,
Desmearing the cavity of the second insulating layer,
An edge surface between the inner wall and the bottom surface of the cavity has a curved surface
A method for manufacturing a printed circuit board.

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