KR20190026993A - Ultra-thin thickness printed circuit board capable of recess height control and method of manufacturing the same - Google Patents

Abstract

Disclosed are an ultra-thin printed circuit board capable of adjusting a recess depth which can additionally reduce the total thickness of a printed circuit board by minimizing a recess depth and can improve alignment of a semiconductor chip in flip chip bonding, and a manufacturing method thereof. According to the present invention, the ultra-thin printed circuit board capable of adjusting a recess depth comprises: a resin layer having a first side and a second side opposite to the first side; a bump pad disposed on the first side of the resin layer; a ball land disposed on the second side of the resin layer; a via disposed in the resin layer to connect the bump pad and the ball land; a barrier layer disposed at the edge of the first side of the resin layer to expose the bump pad; and a carrier layer stacked on the barrier layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-thin printed circuit board,

The present invention relates to an ultra-thin printed circuit board and a method of manufacturing the same, and more particularly, to a method of manufacturing an ultra-thin printed circuit board and a method of manufacturing the same, which can reduce the overall depth of a printed circuit board by minimizing the recess depth, The present invention relates to an ultra-thin printed circuit board and a method of manufacturing the same.

In recent years, the thinness, high density, and high mounting of semiconductor packages have come to be regarded as important factors in accordance with the demand for light and thin shortening in which the volume of electronic devices is lighter and the weight is lighter due to the high performance of electric and electronic products.

2. Description of the Related Art Currently, capacity of a chip such as a large-capacity random access memory (RAM) and a flash memory is increasing with increasing storage capacity of a computer, a notebook, and a mobile phone, but the package tends to be miniaturized It is a situation.

Therefore, the size of a package used as a core part has been studied and developed in a tendency to be miniaturized, and various techniques for mounting a larger number of packages on a limited size substrate have been proposed and studied.

Hereinafter, a conventional printed circuit board will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a conventional printed circuit board, and FIG. 2 is an enlarged view of a portion A of FIG. 1 and 2 show a state before the carrier layer is removed from the printed circuit board.

1 and 2, a conventional printed circuit board 1 includes a bump pad 20 disposed on a first surface 10a of a resin layer 10 and a bump pad 20 disposed on a first surface 10a of the resin layer 10, A ball land 30 is disposed on the second surface 10b and a via 40 for electrically connecting the bump pad 20 and the ball land 30 is disposed in the resin layer 10. A solder mask pattern 50 having an opening G for exposing a part of the ball land 30 may further be disposed on the second surface 10b of the resin layer 10. [

The conventional printed circuit board 1 has a structure in which the bump pad 20 is removed during the process of etching the carrier layer 5 covering the bump pad 20 disposed on the second surface 10b of the resin layer 10 The recesses R having a height of 5 mu m at maximum are formed due to being removed together and being lost.

For this reason, in consideration of the loss of the bump pads 20 during the process of etching the carrier layer 5, the conventional printed circuit board 1 has a recess height R of about 3 to 5 μm The thickness of the resin layer 10 should be as thick as 8 to 15 占 퐉 and the thickness of the resin layer 10 should also be as large as 13 to 18 占 퐉. Therefore, it is difficult to realize the ultra-thin printed circuit board 1.

In addition, since the conventional printed circuit board 1 is designed to have a recess (R) at a considerably high height of 5 mu m at maximum, a semiconductor chip (not shown) There has been a problem of causing cracks in the process of chip bonding.

A related prior art is Korean Patent Laid-Open Publication No. 10-2010-0110459 (published on October 13, 2010), which discloses a method of manufacturing an ultra-thin metal printed circuit board.

It is an object of the present invention to provide an ultrathin printed circuit board capable of further reducing the total thickness of the printed circuit board by minimizing the recess depth and capable of adjusting the recess depth to improve the degree of alignment of the semiconductor chip upon flip chip bonding And a method for producing the same.

According to an aspect of the present invention, there is provided an ultra-thin printed circuit board capable of adjusting a recess depth, comprising: a resin layer having a first surface and a second surface opposite to the first surface; A bump pad disposed on a first side of the resin layer; A ball land disposed on a second side of the resin layer; Vias disposed within the resin layer for connecting the bump pads and the ball lands; A barrier layer disposed on a first side edge of the resin layer to expose the bump pad; And a carrier layer stacked on the barrier layer.

According to an aspect of the present invention, there is provided a method of fabricating an ultra-thin printed circuit board capable of adjusting a recess depth, the method comprising: (a) forming a barrier layer on a carrier layer; (b) forming a bump pad on the barrier layer; (c) bonding the resin layer and the metal layer onto the barrier layer on which the bump pad is formed; (d) removing a portion of the metal layer and the resin layer to form through vias exposing the bump pads; (e) forming vias in the through vias connected to the bump pads and a ball land disposed on the resin layer and connected to the vias; (f) forming a solder mask pattern having an opening exposing a portion of the ball land, the solder mask pattern covering the resin layer; And (g) forming a carrier layer and a barrier layer in a frame shape by removing a part of the carrier layer and the barrier layer to expose the bump pad.

Since the height of the recess can be minimized by arranging the barrier layer between the carrier layer and the bump pad, the ultra-thin printed circuit board capable of adjusting the recess depth according to the present invention and the method of manufacturing the same, It is possible to reduce the thickness of the bump pad and the resin layer, so that it becomes possible to manufacture an ultra-thin printed circuit board.

In addition, since the recess is formed at a considerably low height of 1 占 퐉 or less as the barrier layer is disposed between the carrier layer and the bump pad, the ultra-thin printed circuit board capable of adjusting the recess depth according to the present invention, voids will not occur, so cracks are prevented from occurring during flip-chip bonding of the semiconductor chip to the bump pads, thereby improving the reliability of mounting.

In addition, since the carrier layer and the barrier layer disposed at the edges of the resin layer are formed in a frame shape, the carrier layer and the barrier layer are formed in the ultra-thin printed circuit And serves as a reinforcing member for reinforcing the edge of the substrate, thereby preventing the substrate from being warped.

1 is a cross-sectional view of a conventional printed circuit board.
Fig. 2 is an enlarged view of a portion A in Fig. 1; Fig.
3 is a cross-sectional view of an ultra-thin printed circuit board capable of adjusting the recess depth according to an embodiment of the present invention.
Fig. 4 is an enlarged view of a portion B in Fig. 3; Fig.
5 to 16 are sectional views showing a method of manufacturing an ultra-thin printed circuit board capable of adjusting the recess depth according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ultra-thin printed circuit board and a method of manufacturing the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view of an ultra-thin printed circuit board capable of adjusting the recess depth according to an embodiment of the present invention, and FIG. 4 is an enlarged view of a portion B of FIG. In this case, FIG. 4 shows a state before the barrier layer is etched.

3 and 4, an ultra-thin printed circuit board 100 capable of adjusting the recess depth according to an embodiment of the present invention includes a resin layer 110, a bump pad 120, a ball land 130, 140, a barrier layer 150, and a carrier layer 160.

The resin layer 110 has a first surface 110a and a second surface 110b opposite to the first surface 110a. The resin layer 110 constitutes the body of the printed circuit board 100, and at least one material selected from a prepreg, a polyimide resin, and an epoxy resin may be used as the material of the resin layer 110.

The bump pad 120 is disposed on the first surface 110a of the resin layer 110. [ At this time, the bump pad 120 may be disposed to be embedded in the first surface 110a of the resin layer 110. The bump pad 120 may be disposed at a central portion of the first surface 110a of the resin layer 110, but is not limited thereto.

At this time, the bump pad 120 is formed for flip-chip bonding with a semiconductor chip (not shown). Preferably, copper (Cu) having excellent conductivity is used as the material of the bump pad 120. However, Can be used without limitation.

The ball lands 130 are disposed on the second surface 110b of the resin layer 110. [ The ball land 130 may be disposed at a central portion of the second surface 110b of the resin layer 110, but is not limited thereto. The ball land 130 is formed to be connected to a solder ball (not shown). Preferably, the ball land 130 is formed of copper (Cu) having excellent conductivity. However, the ball land 130 is not necessarily limited thereto. Can be used without limitation.

The via electrode 140 is disposed inside the resin layer 110 to electrically connect the bump pad 120 and the ball land 130. At this time, the via electrode 140 is preferably formed of the same material as the bump pad 120 and the ball land 130.

The barrier layer 150 is disposed at the edge of the first surface 110a of the resin layer 110 to expose the bump pad 120. [

The carrier layer 160 is deposited on the barrier layer 150. The barrier layer 150 and the carrier layer 160 each have a frame shape disposed along the edge of the first surface 110a of the resin layer 110. [

Here, the barrier layer 150 may be formed by removing by a selective etching process using an etchant. Since the etchant used in the process of removing the barrier layer 150 is an etchant that is not reacted with the carrier layer (not shown) and the bump pad 120, the bump pad 120, which is disposed under the barrier layer 150, Can be minimized by etching together. For this purpose, it is preferable to use at least one selected from the group consisting of nickel (Ni), tin (Sn), and titanium (Ti) as the material of the barrier layer 150.

As a result, a portion of the thickness of the bump pad 120 under the barrier layer 150 may be removed to form a recess R, but the recess R may be formed at a significantly lower height d, .

Accordingly, since the height d of the recess R can be minimized, it is not necessary to consider the thickness increase of the bump pad 120 due to the occurrence of an excessive thickness of the recess R, And the thickness of the resin layer 110 can also be reduced, so that it becomes possible to manufacture the ultra-thin printed circuit board 100.

As a result, the bump pad 120 may have a thickness of 2 to 15 mu m, and the resin layer 110 may have a thickness of 5 to 25 mu m.

Since the carrier layer 160 and the barrier layer 150 disposed at the edges of the resin layer 110 are formed in a frame shape, the carrier layer 160 and the barrier layer 150 reinforce the edges of the ultra-thin printed circuit board Thereby preventing warping of the substrate.

In addition, the ultra-thin printed circuit board 100 capable of adjusting the recess depth according to the embodiment of the present invention may further include a solder mask pattern 170.

The solder mask pattern 170 is disposed on the second surface 110b of the resin layer 110 to cover the second surface 110b and the ball land 130 of the resin layer 110 and to cover the ball lands 130 (Not shown).

The solder mask pattern 170 may be formed of one or more materials selected from PSR (photo solder resist), photosensitive liquid coverlay, photo polyimide film, and epoxy resin. have.

Since the height of the recess can be minimized, it is not necessary to consider the thickness increase of the bump pad due to the excessive recess, The thickness of the ground layer can also be reduced, so that it becomes possible to manufacture an ultra-thin printed circuit board.

Further, since the recess is formed at a considerably low height of 1 μm or less in the recess-depth-adjustable recessed printed circuit board according to the present invention, voids are not generated, and the semiconductor chip is flip-chip bonded to the bump pad It is possible to prevent cracks from occurring during the process, thereby improving the reliability of mounting.

In addition, since the carrier layer and the barrier layer disposed at the edges of the resin layer are formed in a frame shape, the carrier layer and the barrier layer are formed on the edge of the ultra-thin printed circuit board And serves as a reinforcing member to prevent warping of the substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of manufacturing an ultra-thin printed circuit board capable of adjusting the recess depth according to an embodiment of the present invention will be described with reference to the accompanying drawings.

5 to 16 are cross-sectional views illustrating a method of manufacturing an ultra-thin printed circuit board capable of adjusting the recess depth according to an embodiment of the present invention.

As shown in FIG. 5, a barrier layer 150 is formed on the carrier layer 160. At this time, the carrier layer 160 is preferably made of copper (Cu) having excellent chemical etchability, but is not necessarily limited thereto, and any metal material having chemical etchability can be used without limitation.

The barrier layer 150 may be formed by a plating or vapor deposition method. At this time, electroplating or electroless plating may be used for the plating, and chemical vapor deposition (CVD), physical vapor deposition (PVD), or the like may be used for the deposition, but the present invention is not limited thereto.

The barrier layer 150 is formed of a metal that does not react with the etchant reacting with the carrier layer 160. For this purpose, it is preferable to use at least one selected from the group consisting of nickel (Ni), tin (Sn), and titanium (Ti) as the material of the barrier layer 150.

At this time, the barrier layer 150 preferably has a thickness of 1 to 5 mu m. If the thickness of the barrier layer 150 is less than 1 탆, the barrier layer 150 may not be properly performed between the carrier layer 160 and the bump pad 120 (FIG. 3). Conversely, when the thickness of the barrier layer 150 exceeds 5 占 퐉, the barrier layer 150 may have a non-uniform thickness distribution and increase the time for forming or removing the barrier layer 150.

Next, as shown in FIG. 6, a first mask pattern M1 is formed on the barrier layer 150 so as to cover a portion except the bump pad formation region. As a result, the barrier layer 150 in the bump pad formation region is exposed to the outside by the first mask pattern M1.

As shown in FIG. 7, a first plating process using a first mask pattern M1 is performed to form a bump pad 120 in a bump pad forming region. As described above, by performing the first plating using the first mask pattern M1, the bump pad 120 is formed by selectively filling the plating liquid in the bump pad forming region.

Next, the first mask pattern M1 is removed from the barrier layer 150 in which the bump pad 120 is formed. At this time, the first mask pattern M1 may be removed by a stripping process using a stripping liquid.

As shown in FIG. 8, the resin layer 110 and the metal layer 130a are bonded to the barrier layer 150 on which the bump pad 120 is formed.

At this time, after the resin layer 110 having the metal layer 130a is disposed on the upper part of the barrier layer 150 where the bump pad 120 is formed, the barrier layer 150 and the resin layer 110 The first surface 110a may be arranged to face the first surface 110a. Thus, the resin layer 110 and the metal layer 130a are sequentially stacked on the barrier layer 150 on which the bump pad 120 is formed.

Here, the resin layer 110 is a part forming the body of the printed circuit board 100, and at least one material selected from a prepreg, a polyimide resin, and an epoxy resin may be used as the material of the resin layer 110.

Next, as shown in FIG. 9, the metal layer 130a and a part of the resin layer 110 are removed to form through vias V for exposing the bump pads 120. Next, as shown in FIG. The through vias V may be formed by any one of a laser drilling method, a developing method, an etching method, and the like.

As shown in FIG. 10, a second mask pattern M2 is formed on the metal layer 130a to cover a portion except for the ball land formation region. As a result, the ball land forming area disposed outside the second mask pattern M2 is exposed to the outside.

As shown in Fig. 11, a secondary plating is performed through the bump pad 120 and the metal layer 130a to form vias 140 filled in through vias (V in Fig. 10), vias 140, A metal plating layer 130b filled on the metal layer 130a is formed.

Next, the second mask pattern M2 is removed. At this time, the second mask pattern M2 may be removed by a strip process using a peeling liquid.

As shown in FIG. 12, the metal layer (130a in FIG. 11) exposed to the outside of the metal plating layer (130b in FIG. 11) is removed to form a ball land 130 connected to the via 140. At this time, the metal layer exposed to the outside of the metal plating layer can be removed by flash etching.

Next, a solder mask layer 170a covering the second surface 110b of the resin layer 110 on which the ball lands 130 are formed is formed. At this time, the solder mask layer 170a may be formed of one or more materials selected from PSR (photo solder resist), photosensitive liquid coverlay, photo polyimide film, and epoxy resin .

12, a portion of the solder mask layer 170a (FIG. 12) covering the ball land 130 is removed to form a solder mask pattern (not shown) having an opening G for exposing a portion of the ball land 130 170 are formed. The opening G may be formed by removing the solder mask layer covering the resin layer 110 and the ball lands 130 by any one method selected from a laser drilling method, a developing method, an etching method, or the like.

A third mask pattern M3 covering the second face 110b and the opening (G in Fig. 13) of the resin layer 110 and a third mask pattern M3 covering the other edge of the carrier layer 160 4 mask pattern M4 are formed. As a result, the second surface 110b and the opening of the resin layer 110 are entirely protected by the third mask pattern M3, and the carrier layer 160 is protected by the fourth mask pattern M4 The central portion is exposed to the outside.

15, the carrier layer 160 exposed to the outside of the fourth mask pattern M4 through the third and fourth mask patterns M3 and M4 is firstly etched to form a carrier layer (160).

Since the barrier layer 150 formed of a metal which is not reacted with the etching solution reacting with the carrier layer 160 is formed under the carrier layer 160 during the first etching process, Can be stably protected by the barrier layer 150.

16, the barrier layer 150 exposed by the carrier layer 160 is secondarily etched using the carrier layer 160 as a mask to form the barrier layer 150 in the form of a frame . Accordingly, the barrier layer 150 and the carrier layer 160 can be designed to have a frame shape along the edge of the first surface 110a of the resin layer 110 with the same area.

In this case, since the etching solution used in the process of removing the barrier layer 150 by the secondary etching is an etching solution which is not reacted with the bump pad 120, the bump pad 120 disposed under the barrier layer 150 It is possible to minimize the removal by etching.

As a result, by the secondary etching, a part of the thickness of the bump pad 120 under the barrier layer 150 can be removed to form the recess R, but the recess R has a thickness of 1 μm or less And is formed at a low height.

Therefore, in the present invention, since the barrier layer 150 is disposed between the carrier layer 160 and the bump pad 120, the height of the recess R can be minimized, It is not necessary to consider the increase in the thickness of the pad 120 and the thickness of the bump pad 120 and the resin layer 110 can also be reduced, thus making it possible to manufacture the ultra-thin printed circuit board 100.

As a result, the bump pad 120 may have a thickness of 2 to 15 mu m, and the resin layer 110 may have a thickness of 5 to 25 mu m.

Since the carrier layer 160 and the barrier layer 150 disposed at the edges of the resin layer 110 are formed in a frame shape, the carrier layer 160 and the barrier layer 150 reinforce the edges of the ultra-thin printed circuit board Thereby preventing warping of the substrate.

Next, the third and fourth mask patterns (M3 and M4 in Fig. 15) are removed from the resin layer 110 and the carrier layer 160. Then, At this time, the third and fourth mask patterns can be removed by a strip process using a peeling liquid.

As described above, according to the method of manufacturing an ultra-thin printed circuit board capable of adjusting the recess depth according to the embodiment of the present invention, since the barrier layer is disposed between the carrier layer and the bump pad, the height of the recess can be minimized, It is not necessary to consider an increase in the thickness of the bump pad due to the occurrence of the recess, and the thickness of the bump pad and the resin layer can also be reduced, so that it becomes possible to manufacture an ultra-thin printed circuit board.

Also, in the method of manufacturing an ultra-thin printed circuit board capable of adjusting the recess depth according to the embodiment of the present invention, since the barrier layer is disposed between the carrier layer and the bump pad, a recess is formed at a considerably low height of 1 탆 or less, there is no fear that voids will occur, so that cracks are prevented from occurring in the process of flip-chip bonding the semiconductor chip to the bump pad, thereby improving the reliability of mounting.

In addition, since the carrier layer and the barrier layer disposed at the edges of the resin layer are formed in a frame shape, the carrier layer and the barrier layer can be formed in the ultra-thin printing And serves as a reinforcing member for reinforcing the edge of the circuit board, thereby preventing warpage of the board.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

100: ultra-thin printed circuit board 110: resin layer
110a: first surface of the resin layer 110b: second surface of the resin layer
120: Bump pad 130: Ball land
140: via 150: barrier layer
160: Carrier layer 170: Solder mask pattern
G: opening

Claims (15)

A resin layer having a first side and a second side opposite to the first side;
A bump pad disposed on a first side of the resin layer;
A ball land disposed on a second side of the resin layer;
Vias disposed within the resin layer for connecting the bump pads and the ball lands;
A barrier layer disposed on a first side edge of the resin layer to expose the bump pad; And
A carrier layer stacked on the barrier layer;
And an adjustable recess depth comprising the substrate.
The method according to claim 1,
The bump pad has a thickness of 2 to 15 mu m,
Wherein the resin layer has a thickness of 5 to 25 占 퐉.
The method according to claim 1,
The bump pad
Wherein the resin layer has a recess that is disposed to be embedded in the first surface of the resin layer and has a thickness that is partially removed.
The method of claim 3,
The recess
Wherein the height of the recess is less than or equal to 1 占 퐉.
The method according to claim 1,
The barrier layer
Wherein at least one selected from the group consisting of nickel (Ni), tin (Sn), and titanium (Ti) is contained.
The method according to claim 1,
The barrier layer
And a thickness of 1 to 5 mu m.
The method according to claim 1,
The ultra-thin printed circuit board
And a solder mask pattern disposed on the second surface of the resin layer and covering the second surface of the resin layer and the ball land and having an opening exposing a portion of the ball land, Ultra-thin printed circuit board with adjustable depth.
(a) forming a barrier layer on a carrier layer;
(b) forming a bump pad on the barrier layer;
(c) bonding the resin layer and the metal layer onto the barrier layer on which the bump pad is formed;
(d) removing a portion of the metal layer and the resin layer to form through vias exposing the bump pads;
(e) forming vias in the through vias connected to the bump pads and a ball land disposed on the resin layer and connected to the vias;
(f) forming a solder mask pattern having an opening exposing a portion of the ball land, the solder mask pattern covering the resin layer; And
(g) removing a portion of the carrier layer and the barrier layer to expose the bump pad to form a carrier layer and a barrier layer in the form of a frame;
Wherein the recess depth is adjustable.
9. The method of claim 8,
In the step (a)
The barrier layer
Wherein at least one selected from the group consisting of nickel (Ni), tin (Sn), and titanium (Ti) is contained.
9. The method of claim 8,
In the step (a)
The barrier layer
The method of claim 1, wherein the thickness of the recess is about 1 to 5 mu m.
9. The method of claim 8,
The step (b)
(b-1) forming a first mask pattern on the barrier layer, the first mask pattern covering a portion excluding the bump pad formation region;
(b-2) performing a first plating process using the first mask pattern to form a bump pad in the bump pad formation region; And
(b-3) removing the first mask pattern from the barrier layer on which the bump pad is formed;
Wherein the recess depth is adjustable. ≪ RTI ID = 0.0 > 11. < / RTI >
9. The method of claim 8,
The step (e)
(e-1) forming a second mask pattern on the metal layer, the second mask pattern covering a portion except for the ball land formation region;
(e-2) performing a secondary plating through the bump pad and the metal layer to form a via filled in the through via, and a metal plating layer filled on the via and the metal layer; And
(e-3) removing the metal layer exposed to the outside of the metal plating layer after removing the second mask pattern, thereby forming a ball land connected to the via;
Wherein the recess depth is adjustable. ≪ RTI ID = 0.0 > 11. < / RTI >
9. The method of claim 8,
The step (g)
(g-1) forming a third mask pattern covering the second surface and the opening of the resin layer, and a fourth mask pattern covering a part of the edge of the carrier layer;
(g-2) forming a carrier layer in a frame shape by first etching the carrier layer exposed outside the fourth mask pattern;
(g-3) forming a barrier layer in a frame shape by secondary etching the barrier layer exposed by the carrier layer; And
(g-4) removing the third and fourth mask patterns from the resin layer and the carrier layer;
Wherein the recess depth is adjustable. ≪ RTI ID = 0.0 > 11. < / RTI >
14. The method of claim 13,
In the step (g-3)
By the secondary etching,
Wherein a thickness of the bump pad below the barrier layer is removed to form a recess.
15. The method of claim 14,
The recess
The method of claim 1, wherein the height of the recess is less than 1 占 퐉.

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