KR20060105382A - Printed circuit board joining structure and method the same - Google Patents

Abstract

The present invention relates to a bonded structure of a printed circuit board and a method thereof. The bonding structure of the present invention includes a first printed circuit board 10 having an insulating layer 11 and a circuit pattern 13 formed therein and a bump 17 protruding from a surface thereof, and an insulating layer 21 therein. And a second printed circuit board 20 having a circuit pattern 13 and having a hole 27 through which a bump 17 of the first printed circuit board 10 is pressed into a surface thereof. The bumps 17 of the first printed circuit board 10 are pressed into the holes 27 of the second printed circuit board 20 and bonded to each other. The bump 17 is formed to protrude in a columnar shape, the longitudinal section of which is either rectangular or trapezoidal. According to the bonded structure and the method of the printed circuit board according to the present invention having the above-described configuration, a high temperature environment is not required at the time of bonding between the printed circuit boards, so that the printed circuit board or the components mounted thereon are affected by heat. Do not receive. Therefore, according to the present invention, even though the bonding between the printed circuit boards is more firm, the printed circuit board and the components mounted thereon are not damaged by heat, thereby increasing the yield and operation reliability of the product.

Printed Circuit Board, Bonding, Bump, Blind Beer Hole, Metal Adhesive Layer, Conductive Adhesive

Description

Printed circuit board joining structure and method the same}

1 is a cross-sectional view showing the configuration of a general multi-stack package.

Figure 2 is a cross-sectional view showing a problem of the bonding structure of a conventional printed circuit board.

Figure 3 is a cross-sectional view showing the configuration of a first embodiment of a bonded structure of a printed circuit board according to the present invention.

4A to 4D are cross-sectional views showing a cross sectional configuration of bumps constituting the first embodiment of the present invention.

5A to 5F are sequential views showing an example of a manufacturing process of a first printed circuit board constituting the first embodiment of the present invention.

6A to 6C are flowcharts sequentially showing an example of a manufacturing process of a second printed circuit board constituting the first embodiment of the present invention.

7 is a cross-sectional view showing a configuration of a second embodiment of the present invention.

8 is a cross-sectional view showing a configuration of a third embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: first printed circuit board 11: insulating layer

13: circuit pattern 14: bump pad

15: solder resist 17: bump

17 ': plating layer 20: second printed circuit board

21: insulating layer 23: circuit pattern

27: Beer hall

The present invention relates to a printed circuit board, and more particularly, to a structure and method for bonding the printed circuit board and the printed circuit board to be electrically connected.

As the electronic products become more versatile and smaller in size, there is a need for high integration of electronic components inside the electronic products. To this end, one chip is conventionally made into one package, but recently, a multi-stack package stacking a plurality of chips and a printed circuit board on which a chip is mounted is a multi-chip package. Is used a lot.

1 is a cross-sectional view showing the configuration of a typical multi-stack package. According to this, the chip 3 is mounted on each printed circuit board 1. A plurality of printed circuit boards 1 on which the chips 3 are mounted are sequentially stacked. The electrical connection between the printed circuit board 1 is made by solder balls 5. Of course, when the multi-stack package is mounted on another printed circuit board, the solder ball 5 provided on the lowermost printed circuit board 1 is soldered to the other printed circuit board.

On the other hand, recently, the use of environmentally friendly products (Pb) do not use a solder (Solder) is a general trend. That is, when soldering the solder ball 5, a solder containing no lead is used.

However, the prior art as described above has the following problems.

That is, in order to stack the substrates 1 on which the chips 3 are mounted, respectively, the substrates 1 and 1 must be electrically connected between the substrates 1 through the solder balls 5. Therefore, every time the substrate 1 is laminated, a soldering operation must be performed, and the multi-stack package once made in the state of FIG. 1 is mounted on another substrate through the solder balls 5.

As such, a lot of heat is generated in the process of electrically connecting the substrate 1 through the solder ball, and the heat affects other components including the chip 3 mounted on the substrate 1.

For example, as shown in FIG. 3, the solder balls 5 connecting between the substrate 1 and the substrate 1 are bonded to the upper and lower substrates 1 by soldering, respectively. In more detail, the solder balls 5 are bonded onto the ball pads 1 'formed on each substrate. However, the use of lead-free solder requires that the working temperature be relatively high. Such high temperature affects the substrate 1 itself and components such as the chip 3 mounted on the substrate 1. Therefore, as the chip 3 is damaged by heat, the yield of the product is lowered, and the tip 3 is affected by the heat, which adversely affects the operation reliability of the product. In particular, components such as RAM are very sensitive to heat, which dramatically reduces the yield of the package.

On the other hand, the use of environmentally friendly materials to be soldered at a relatively high temperature, the heat effect caused by this causes the crack (7) is generated adjacent to the portion where the solder ball 5 and the ball pad (1 ') are bonded to each other. . That is, the crack 7 is generated in a relatively weak part while the intermetallic compound is formed at the portion where the ball pad 1 'and the solder ball 5 are coupled by the thermal shock. Generally, as shown in FIG. 2, in the solder ball 5, in the state in which the solder ball 5 is mounted on the substrate 1, cracks 7 are generated adjacent to the portion where the intermetallic compound is formed.

As such, when the cracks 7 are generated in the solder balls 5, the bonding force between the substrates 1 becomes weak and the substrate 1 and the substrates 1 are separated from each other by a force applied from the outside. .

Accordingly, an object of the present invention is to solve the problems of the prior art as described above, and is to bond the printed circuit board and the printed circuit board to be electrically connected using structural characteristics.

Another object of the present invention is to bond a printed circuit board and a printed circuit board to be electrically connected to each other at relatively low temperature conditions.

Still another object of the present invention is to bond a printed circuit board and a printed circuit board to be electrically connected to each other using a conductive adhesive.

According to a feature of the present invention for achieving the above object, there is provided a first printed circuit board having an insulating layer and a circuit pattern therein and bumps formed on the surface thereof, and an insulating layer and a circuit pattern therein; And a second printed circuit board having a perforated hole in which the bump of the first printed circuit board is pressed into a surface thereof, and the bumps of the first printed circuit board are pressed into the holes of the second printed circuit board to each other. Are bonded.

The bump is formed to protrude in a columnar shape, the longitudinal section of which is either rectangular or trapezoidal.

An ablation portion is formed on the outer circumferential surface of the bump in the longitudinal direction of the bump to form a predetermined gap between the bump and the inner surface of the hole.

The bumps are formed by any one of plating, etching or printing.

The hole is either a blind via hole or a through hole, and an inner surface thereof has a plating layer electrically connected to a circuit pattern of a second printed circuit board.

On the surface of the bump and the inner surface of the hole, a metal bonding layer which can be joined by diffusion is formed.

The bump and the hole may be bonded by a conductive adhesive.

According to another aspect of the invention, the present invention comprises the steps of forming a bump on the surface of the first printed circuit board, and forming a hole in which the bump is pressed in a position corresponding to the bump of the surface of the second printed circuit board And bonding the bumps of the first printed circuit board to the holes of the second printed circuit board to bond the first printed circuit board and the second printed circuit board.

The bumps are formed on the bump pads formed on the surface of the first printed circuit board by any one of plating, etching or printing methods.

The hole is formed by a laser drill on the surface of the second printed circuit board, and may be either a blind via hole or a through hole.

The bump and the hole are further formed on the surface of the metal adhesive layer which can be bonded by diffusion.

A conductive adhesive is provided between the bump and the hole and adhered to each other.

According to another feature of the invention, the present invention has an insulating layer and a circuit pattern therein, the bump is formed on the surface protruding, the first printed circuit board having a metal adhesive layer formed on the surface of the bump; A second printed circuit board having an insulating layer and a circuit pattern therein, a connection pad being formed at a position corresponding to the bump of the first printed circuit board, and a metal adhesive layer formed on a surface of the connection pad; And a metal adhesive layer formed on the bump surface of the first printed circuit board and the connection pad surface of the second printed circuit board.

The metal adhesive layer is formed of a conductive material bonded at a temperature that does not give a thermal shock to the printed circuit board and its mounting components.

The metal adhesive layer is formed of any one of gold (Au), silver (Ag), and zinc (Zn).

The bumps are formed by any one of plating, etching or printing.

According to another feature of the invention, the present invention comprises the steps of forming a metal adhesive layer on the surface of the bump provided on the first printed circuit board, and the surface of the connection pad provided in a position corresponding to the bump of the first printed circuit board And forming a metal adhesive layer on the bump surface, and bonding the metal adhesive layer on the bump surface and the metal adhesive layer on the connection pad surface at a temperature at which the printed circuit board and the mounted component are not subjected to thermal shock.

The metal adhesive layer is formed of any one of gold (Au), silver (Ag), and zinc (Zn).

According to another feature of the present invention, the present invention has a first printed circuit board having an insulating layer and a circuit pattern therein and bumps protruding from the surface thereof, and an insulating layer and a circuit pattern therein and having the first printed circuit therein. And a second printed circuit board having a connection pad formed at a position corresponding to the bump of the circuit board, and a conductive adhesive interposed between the bump and the connection pad to electrically connect and bond them.

The conductive adhesive is an anisotropic conductive film or an anisotropic conductive paste.

According to the bonded structure and the method of the printed circuit board according to the present invention having the above-described configuration, a high temperature environment is not required at the time of bonding between the printed circuit boards, so that the printed circuit board or the components mounted thereon are affected by heat. Do not receive. Therefore, according to the present invention, even though the bonding between the printed circuit boards is more firm, the printed circuit board and the components mounted thereon are not damaged by heat, thereby increasing the yield and operation reliability of the product.

Hereinafter, exemplary embodiments of a bonded structure and a method of a printed circuit board according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view showing a first embodiment of a bonded structure of a printed circuit board according to the present invention, and FIG. 4 is a cross-sectional view showing examples of cross-sectional shapes of bumps constituting an embodiment of the present invention.

As shown in these figures, the first printed circuit board 10 has a circuit pattern 13 and a bump pad 14 formed on the surface of the insulating layer 11. In the drawing, although the first printed circuit board 10 is formed with the circuit pattern 13 and the bump pad 14 formed on the surface of one insulating layer 11, the insulating circuit 11 is not necessarily the same. It may be a multilayer printed circuit board composed of. The solder resist 15 is coated on the surface of the first printed circuit board 10 so that the circuit pattern 13 is not exposed. However, the portion where the bump pad 14 is formed is not covered by the solder resist 15.

The bump pad 14 protrudes from the bump pad 14. The bumps 17 are for electrically connecting the first printed circuit board 10 and the second printed circuit board 20 to be described below and bonding them to each other. The bump 17 may be formed in various ways.

That is, the bump 17 may be formed on the bump pad 14 through a plating process. This process is illustrated in FIG. 5 to be described below. As another method of forming the bumps 17 on the bump pads 14, a portion of the relatively thick metal layer integrated with the bump pads 14 is formed by etching to remove portions except the portions to be the bumps 17. can do. In addition, the bump 17 may be formed by printing a conductive paste on the bump pad 14.

Here, the shape of the said bump 17 is demonstrated. 3, the longitudinal cross section of the said bump 17 is substantially square shape. However, this is not necessarily the case, and the cross section may be trapezoidal. The shape of the bumps 17 may vary depending on the method of forming the bumps 17, and it may be better that the longitudinal cross section has a rectangular coupling force with the counterpart.

Meanwhile, a longitudinal cross-sectional shape of the bump 17 will be described with reference to FIG. 4. For reference, the bump 17 is formed to protrude in a substantially columnar shape.

4A shows a bump 17 having a circular cross-sectional shape. The bump 17 is press-fitted into the blind-bearing hole 27 to be described below. If the cross section is circular, the contact area for electrical and structural connection can be maximized. Therefore, the stability of the electrical connection and the fastening force for the structural connection can be the largest.

4b shows that the cross section of the bump 17 is hexagonal. As such, when the cross section of the bump 17 is a hexagon, the entire outer circumferential surface of the bump 17 is not in contact with the inner surface of the blind bead hole 27, but line contact is made along a portion corresponding to the vertex of the hexagon. In this case, the electrical and structural connection may be relatively weak, but when the bump 17 is inserted into the blind bead hole 27, air is not left inside the blind bead hole 27 so that the bump 17 is blind. It can be fully inserted into the via hole 27.

On the other hand, in Figure 4c and 4d while ensuring the contact area necessary for electrical and structural connection of the bump 17 and the blind bead hole 27, the air is smoothly discharged when the bump 17 and the blind bead hole 27 is combined It is shown that the cutting portion 17c is formed in the longitudinal direction along the outer circumferential surface of the bump 17 so as to be possible. The cross-sectional shape of the ablation portion 17c may be various in addition to a bow and a fan.

The plating layer 17 ′ is formed on the bump 17 and the bump pad 14. The plating layer 17 ′ serves to prevent oxidation of the surface of the bump 17. Of course, the bump 17 also serves to make the electrical connection with the counterpart through which the electrical connection is made more reliably. Such a plating layer 17 'does not necessarily have to be formed on the entire surface of the bump 17 and the bump pad 14, and can be formed only in necessary portions.

Now, a configuration of the second printed circuit board 20 electrically and structurally connected to the first printed circuit board 10 will be described. The second printed circuit board 20 also includes a circuit pattern 21 formed on the surface of the insulating layer 21. The second printed circuit board 20 may also be multilayered. That is, the configuration of the second printed circuit board 20 is also substantially similar to that of the first printed circuit board 10.

However, the blind via hole 27 through which the bump 17 is pressed is formed in the second printed circuit board 20. A plating layer 27 ′ is formed on an inner surface of the blind beer hole 27 to enable electrical connection between the bump 17 and the circuit pattern 23 of the second printed circuit board 20. In the drawing, the plating layer 27 'is electrically connected to the circuit pattern 23 inside the second printed circuit board 20. However, the plating layer 27' is not necessarily the surface of the second printed circuit board 20. It may be electrically connected to the circuit pattern 23 formed in the. The blind beer hole 27 is dimensionally designed so that the bump 17 can be press-fitted.

Now, a process of manufacturing the first printed circuit board will be described with reference to FIG. 5. In FIG. 5A, a first printed circuit board 10 having a circuit pattern 13 and a bump pad 14 formed on an insulating layer 11 and having a surface except for the bump pad 14 covered with a solder resist 15 is illustrated. ) Is shown.

The photoresist 16 is coated on the entire surface of the first printed circuit board 10 of FIG. 5A provided with the bump pads 14 (see FIG. 5B). The surface of the first printed circuit board 10 is applied. Only the portion of the photoresist 16 applied to the bump pad 14 is selectively removed. This can be done through ultraviolet exposure and development. 5C illustrates a state in which only a portion of the photoresist 16 corresponding to the bump pad 14 is selectively removed.

The bumps 17 are formed by plating on the bump pads 14 where the photoresist 16 is removed and exposed. This state is shown in FIG. 5D. Next, the photoresist 16, which has been applied for the formation of the bump 17, is removed to bring it to the state of FIG. 5E.

The plating layer 17 'is formed on the surface of the bump 17 formed on the bump pad 14 with nickel and gold. The state in which the plating layer 17 'is formed as shown in FIG. 5F is shown. The plating layer 17 'may be formed only at a required position according to design conditions.

Meanwhile, FIG. 6 illustrates a process of manufacturing the second printed circuit board constituting the exemplary embodiment of the present invention. Accordingly, as shown in FIG. 6A, the blind via hole 27 is formed in the second printed circuit board 20 in which the circuit pattern 23 is formed in the insulating layer 21. The blind via hole 27 is preferably formed by a laser drill. The blind via hole 27 is formed in FIG. 6B.

Next, a plating layer 27 ′ is formed on an inner surface of the blind beer hole 27. The plating layer 27 ′ is a portion electrically and structurally connected to the outer circumferential surface of the bump 17. This state is shown in FIG. 6C.

For reference, a through hole may be perforated in the second printed circuit board 20 instead of the blind via hole 27 into which the bump 17 of the first printed circuit board 10 is press-fitted. That is, the first printed circuit board 10 and the second printed circuit board 20 are bonded to each other by pressing the bump 17 into the through hole formed to penetrate the second printed circuit board 20. At this time, when the bump 17 is inserted into the barrel hole, air does not remain inside the barrel hole, and thus it is not necessary to form a separate cutout 17c in the bump 17.

The first printed circuit board 10 and the second printed circuit board 20 made through the process disclosed in FIGS. 5 and 6 are electrically and structurally formed by pressing the bumps 17 into the blind bead hole 27. The bond is made. The coupled state is the state of FIG. 3.

Next, a second embodiment of the present invention will be described with reference to FIG. As shown in the figure, the first printed circuit board 110 has a circuit pattern 113 and a bump pad 114 formed on the surface of the insulating layer 111. Although the drawing shows that the first printed circuit board 110 has only one insulating layer 111, the first printed circuit board 110 may be formed of a plurality of insulating layers 111, and at least the bump pad 114 and the bottom surface thereof. What is necessary is just the structure of bump 117 etc. which are demonstrated. The surface of the first printed circuit board 110 is mostly covered by the solder resist 115 except for the bump pad 114.

Bump 117 is formed to protrude from the bump pad 114. The bump 117 may be formed in various ways, such as plating, etching, and printing. The shape of the bump pad 114 may vary as in the first embodiment described above, but the ablation portion is not necessary. The metal adhesive layer 118 is formed on the surface of the bump 117. The metal adhesive layer 118 should be formed at least on the front end surface of the bump 117.

The metal adhesive layer 118 is relatively low temperature, i.e., at a temperature such that a printed circuit board or a component mounted thereon is not subjected to thermal shock, for example, a temperature of 200 ° C or less, and a predetermined pressure to diffuse with the counterpart. It is made of a conductive material that can be bonded by. Examples of the material of the metal adhesive layer 118 include gold (Au), silver (Ag), zinc (Zn), and the like. However, the material forming the metal adhesive layer 118 may be any conductive material, preferably a metal, that can be bonded to the counterpart at the above temperature. The metal adhesive layer 118 may be formed using a method such as electrolytic or electroless plating, deposition, and sputtering.

Meanwhile, the configuration of the second printed circuit board 120 to be bonded to the first printed circuit board 110 will be described. The second printed circuit board 120 has a circuit pattern 123 and a connection pad 124 formed on a surface of the insulating layer 121. The second printed circuit board 120 except for the connection pad 124 is formed. The surface of is covered by solder resist 125.

It is preferable that the metal adhesive layer 124 ′ formed on the surface of the bump 117 is formed on the surface of the connection pad 124. This is to ensure the coupling of the connection pad 124 and the bump 117 more securely.

In this embodiment, the bumps 117 of the first printed circuit board 110 may have the metal adhesive layers 118 and 124 'connected to the connection pads 124 of the second printed circuit board 120 at predetermined temperature conditions. By bonding together by diffusion to each other under.

Next, a third embodiment of the present invention is shown in FIG. For the convenience of description, the drawings and reference numerals of the exemplary embodiment shown in FIG. 7 are used as they are. Reference numeral 117 'is a plating layer.

In the present embodiment, the conductive adhesive 130 is used to bond the first printed circuit board 110 and the second printed circuit board 120. That is, the conductive adhesive 130 is interposed between the front end surface of the bump 117 of the first printed circuit board 110 and the connection pad 124 of the second printed circuit board 120.

As the conductive adhesive 130, an anisotropic conductive film, anisotropic conductive paste, or the like is used.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self-evident.

For example, the second and third embodiments of the present invention may be used in combination with the coupling method using the bumps 17 and the via holes 27 as in the first embodiment. That is, by forming a metal adhesive layer on the surface of the bump 17 and the inner surface of the via hole 27, the mechanical bonding between the bump 17 and the via hole 27 can be added to the mechanical bonding layer by diffusion of the metal adhesive layer.

In addition, the conductive adhesive 130 may be bonded to the surface of the bump 17 by interposing the inner surface of the via hole 27.

According to the bonding structure and the method of the printed circuit board according to the present invention as described in detail above, the following effects can be obtained.

First, bumps are formed on the first printed circuit board, and holes are formed in the second printed circuit board so that the bumps are press-fitted, so that soldering is unnecessary in bonding the printed circuit boards to each other. Therefore, the printed circuit board and the components mounted thereon are not exposed to thermal shock during the bonding process of the printed circuit board, thereby increasing the yield of the product and improving the operation reliability.

In the structure in which the bump is press-fitted into the hole, when the hole is a blind-bearing hole, an ablation part is provided in the bump so that the air inside the hole is smoothly discharged to the outside while the bump is pressed into the hole. By doing in this way, the bonding state between printed circuit boards becomes more reliable.

In addition, when the bumps of the first printed circuit board and the connection pads of the second printed circuit board are bonded to each other using a metal adhesive layer, the bumps and the connection pads bonded to each other may be bonded to each other at relatively low temperatures. A metal adhesive layer is formed. In the method of bonding the bumps of the first printed circuit board and the connection pads of the second printed circuit board to each other using a conductive adhesive, there is no need to use heat in bonding the printed circuit boards.

Therefore, the printed circuit board and the components mounted thereon are prevented from being damaged by heat at the time of bonding between the printed circuit boards, so that the yield and operation reliability of the product are improved.

On the other hand, the bumps of the first printed circuit board and the holes of the second printed circuit board can be used not only by joining by pressing, but also by using a metal adhesive layer or a conductive adhesive that can be diffused. You can get the effect.

Claims (20)

A first printed circuit board having an insulating layer and a circuit pattern formed therein and bumps protruding from the surface thereof; And a second printed circuit board having an insulating layer and a circuit pattern therein, and having a perforated hole through which a bump of the first printed circuit board is pressed into a surface thereof. And a bump of the first printed circuit board is pressed into a hole of the second printed circuit board and bonded to each other. The bonded structure of claim 1, wherein the bumps are formed to protrude in a columnar shape, and the end surfaces thereof are either rectangular or trapezoidal. 3. The bonding structure of a printed circuit board according to claim 2, wherein a cutout portion is formed in an outer circumferential surface of the bump in a longitudinal direction of the bump to form a predetermined gap between the inner surface of the hole and the cutout portion. The bonding structure of claim 1, wherein the bumps are formed by any one of plating, etching, and printing. The printed circuit board according to any one of claims 1 to 4, wherein the hole is one of a blind beer hole and a through hole, and an inner surface thereof has a plating layer electrically connected to a circuit pattern of a second printed circuit board. Junction structure. 5. The bonding structure of a printed circuit board according to any one of claims 1 to 4, wherein a metal bonding layer that can be bonded by diffusion is formed on the surface of the bump and the inner surface of the hole. The bonding structure of a printed circuit board according to any one of claims 1 to 4, wherein the bump and the hole are bonded by a conductive adhesive. Forming bumps on a surface of the first printed circuit board; Forming a hole in which the bump is pressed in a position corresponding to the bump on the surface of the second printed circuit board; And bonding the first printed circuit board and the second printed circuit board by pressing the bumps of the first printed circuit board into the holes of the second printed circuit board. The method of claim 8, wherein the bump is formed on the bump pad formed on the surface of the first printed circuit board by any one of plating, etching, and printing methods. The method of claim 8, wherein the hole is formed by a laser drill on a surface of the second printed circuit board, and is one of a blind beer hole and a through hole. The method according to any one of claims 8 to 10, further comprising a metal bonding layer formed on the surfaces of the bumps and the holes to be bonded by diffusion. The method according to any one of claims 8 to 10, wherein a conductive adhesive is provided between the bumps and the holes so as to be bonded to each other. A first printed circuit board having an insulating layer and a circuit pattern therein and having bumps formed on a surface thereof, and having a metal adhesive layer formed on a surface thereof; A second printed circuit board having an insulating layer and a circuit pattern therein, a connection pad being formed at a position corresponding to the bump of the first printed circuit board, and a metal adhesive layer formed on a surface of the connection pad; Is configured to include, And a metal bonding layer formed on the bump surface of the first printed circuit board and the connection pad surface of the second printed circuit board to be bonded to each other by diffusion. 15. The bonded structure of claim 13, wherein the metal adhesive layer is formed of a conductive material bonded at a temperature that does not cause thermal shock to the printed circuit board and the mounting component thereof. The bonding structure of a printed circuit board according to claim 13, wherein the metal adhesive layer is formed of any one of gold (Au), silver (Ag), and zinc (Zn). The bonding structure of claim 13, wherein the bumps are formed by any one of plating, etching, and printing. Forming a metal adhesive layer on a surface of the bump provided on the first printed circuit board; Forming a metal adhesive layer on a surface of the connection pad provided at a position corresponding to the bump of the first printed circuit board; And bonding the metal adhesive layer on the bump surface and the metal adhesive layer on the connection pad surface at a temperature at which the printed circuit board and the mounted component are not subjected to thermal shock. 18. The method of claim 17, wherein the metal adhesive layer is formed of any one of gold (Au), silver (Ag), and zinc (Zn). A first printed circuit board having an insulating layer and a circuit pattern formed therein and bumps protruding from the surface thereof; A second printed circuit board having an insulating layer and a circuit pattern therein and having a connection pad formed at a position corresponding to the bump of the first printed circuit board; And a conductive adhesive interposed between the bump and the connection pad to electrically connect them and simultaneously bond them. 20. The bonded structure of claim 19, wherein the conductive adhesive is an anisotropic conductive film or an anisotropic conductive paste.

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