WO2014137002A1

WO2014137002A1 - Soldering joint structure of printed circuit board with excellent solder discharge property

Info

Publication number: WO2014137002A1
Application number: PCT/KR2013/001831
Authority: WO
Inventors: 김영호; 오병헌
Original assignee: (주)드림텍
Priority date: 2013-03-05
Filing date: 2013-03-07
Publication date: 2014-09-12
Also published as: KR101313684B1

Abstract

The soldering joint structure of a printed circuit board according to the present invention includes: a hard PCB consisting of a hard PCB body, and a first external connection terminal arranged at one side end of the hard PCB body; an FPCB consisting of an FPCB body arranged so as to face the hard PCB, a second external connection terminal arranged so as to overlap the first external connection terminal, and a solder discharge hole penetrating the second external connection terminal; and a solder for electrically connecting the first external connection terminal of the hard PCB and the second external connection terminal of the FPCB, characterized in that the solder discharge hole has a width of 0.3-0.5mm and a length of 0.7-0.9mm.

Description

Solder joint structure of printed circuit board with excellent solder drainability

The present invention relates to a solder joint structure of a printed circuit board, and more particularly, to extend the solder discharge hole to an optimal size, and to arrange the external connection terminals in a zigzag form to discharge the solder while utilizing a minimum space. The present invention relates to a soldering joint structure of a printed circuit board capable of improving efficiency.

Recently, portable electronic products such as mobile phones, PDAs, and PMPs are widely used. However, small-sized mobile devices such as mobile phones are having difficulty in installing various functions because of their functionality as well as their ability to be portable.

In particular, recently used ultra-compact mobile devices have been significantly reduced in size so that modules that are applied to general devices cannot be applied, thereby making it impossible to secure enough mounting space. This made it impossible to secure enough mounting space and the size continued to shrink so that it was difficult to apply the protection of the various modules.

As described above, components of various functions are mounted on a substrate in a SMD (Surface Mounted Device) method to realize various functions while the size is continuously reduced.

Particularly, in the related art, a main board of a mobile phone corresponding to a hard area and a board for a universal serial bus (USB) connector corresponding to a flexible area are manufactured as an integrated type by using a connection connector such as a socket. However, in the case of the integrated type, the distance between the USB connector and the connector of the main board of the mobile phone is long, and the manufacturing time is relatively increased as well as the hard area and the flexible area are composed of one printed circuit board (PCB). There was a problem that the production yield is lowered due to the increase in the parts cost due to the use of expensive connector.

Related prior arts are Korean Patent Publication No. 10-2005-0116704 (published Dec. 13, 2005), which discloses a printed circuit board and a semiconductor package module using the same that can improve solder joint reliability (SJR). .

An object of the present invention is to remove the bonding structure between the PCB by soldering each external connection terminal of a hard printed circuit board (PCB) and a flexible printed circuit board (FPCB) separated from each other by fastening with a connection connector. In addition to simplification, the solder discharge hole can be expanded to an optimal size and the external connection terminals are arranged in a zigzag pattern, so that soldering of the printed circuit board can be achieved while utilizing the minimum space and ensuring excellent solder discharge. It is to provide a bonded structure.

Soldering bonding structure of a printed circuit board according to an embodiment of the present invention for achieving the above object is a hard PCB having a hard PCB body, and a first external connection terminal disposed on one end of the hard PCB body; An FPCB body having an FPCB body disposed to face the hard PCB body, a second external connection terminal disposed to overlap the first external connection terminal, and a solder discharge hole passing through the second external connection terminal; And a solder electrically connecting the first external connection terminal of the hard PCB and the second external connection terminal of the FPCB to each other, wherein the solder discharge hole has a width of 0.3 to 0.5 mm and a length of 0.7 to 0.9 mm. It is characterized by.

The soldering bonding structure of the printed circuit board according to the present invention is a soldering bonding method of the hard PCB and the FPCB which are separated from each other without using a connecting connector such as a socket, the first external connection terminal of the hard PCB and the second external connection terminal of the FPCB. By performing direct bonding to selectively make an electrical connection, the joining structure can be simplified to reduce the manufacturing cost and to improve the production yield by shortening the manufacturing time.

In addition, the solder joint structure of the printed circuit board according to the present invention, while extending the solder discharge hole to the optimum size, by aligning the external connection terminals in a zigzag form, the solder discharge efficiency is excellent while utilizing a minimum space Solder bonding can be improved.

In addition, the soldering joint structure of the printed circuit board according to the present invention can be used to design a circuit between the inner layer and the outer layer in a different form by using three or more layers of multilayer substrate as FPCB, inner layer and outer layer circuits There is an advantage that the rearrangement of the liver can be freely used to more effectively utilize the area of the junction between the hard PCB and the FPCB.

1 is a view for explaining a soldering bonded structure of a printed circuit board according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view illustrating a portion of the first external connection terminal of FIG. 1.

3 is an enlarged plan view illustrating a portion of the second external connection terminal of FIG. 1.

4 is a cross-sectional view taken along line IV-IV 'of FIG. 3.

5 is an enlarged plan view illustrating a portion A of FIG. 3.

Fig. 6 is a plan view showing a two-layer circuit terminal portion of an FPCB made of a multilayer substrate having a triple layer structure.

Fig. 7 is a plan view showing a three-layer circuit terminal portion of an FPCB made of a multilayer substrate having a triple layer structure.

FIG. 8 is a cross-sectional view taken along the line VIII-VIII ′ of FIG. 6.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a soldering joint structure of a printed circuit board having excellent solder drainability according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view illustrating a soldering joint structure of a printed circuit board according to an exemplary embodiment of the present invention, and FIGS. 2 and 3 are plan views showing enlarged first and second external connection terminal portions of FIG. 1, respectively. 4 is a cross-sectional view taken along the line IV-IV 'of FIG. 3.

1 to 4, the soldering bonding structure 100 of the printed circuit board according to the embodiment of the present invention shown is a hard printed circuit board (PCB) 120, a flexible printed circuit board (FPCB) 140, and And solder 160. At this time, the soldering bonding structure 100 of the printed circuit board according to the embodiment of the present invention is electrically connected to the hard PCB 120 and the FPCB 140 by the solder 160 is separated from each other.

The hard PCB 120 includes a hard PCB body 122 and a first external connection terminal 125 disposed at one end of the hard PCB body 122.

The hard PCB body 122 has a first surface 120a and a second surface 120b opposite to the first surface 120a. The first external connection terminal 125 is disposed at one end of the first surface 120a of the hard PCB body 122. Although not shown in detail in the drawings, the hard PCB 120 may be, for example, a main board for a mobile phone, but is not necessarily limited thereto, and may be a substrate of various electronic devices. In this case, various components such as a driving element, a transistor, and a resistor may be mounted on the first surface 120a of the hard PCB body 122.

The FPCB 140 includes an FPCB body 142 disposed to face the hard PCB body 122, a second external connection terminal 145 disposed to overlap with the first external connection terminal 125, and a second external connection. The solder discharge hole SH penetrates through the connection terminal 145.

In this case, the FPCB body 142 has a third surface 140a facing the first surface 120a of the hard PCB body 122 and a fourth surface 140b opposite to the third surface 140a. The second external connection terminal 145 is disposed at one end of the third surface 140a of the FPCB body 142 and overlaps the first external connection terminal 125. In addition, the solder discharge hole SH is formed to penetrate the second external connection terminal 145.

Although not shown in detail in the drawings, the FPCB 140 may be, for example, a substrate for a universal serial bus (USB) connector, but is not necessarily limited thereto.

In particular, the FPCB 140 may be a rigid flexible printed circuit board. Rigid flexible printed circuit boards have low contact resistance and short wiring lengths, which is advantageous for high-speed response. In addition, the rigid flexible printed circuit board can be designed three-dimensional circuit to reduce the size of the product.

The solder 160 is interposed in the space between the first external connection terminal 125 of the hard PCB 120 and the second external connection terminal 145 of the FPCB 140 to connect the first external connection of the hard PCB 120. It serves to directly connect the terminal 125 and the second external connection terminal 145 of the FPCB 140.

Soldering bonding structure 100 of the printed circuit board according to the embodiment of the present invention described above is a hard PCB (hard PCB 120 and FPCB 140) to be separated from each other without using a connection connector such as a socket by a hard PCB ( By directly bonding the first external connection terminal 125 of the 120 and the second external connection terminal 145 of the FPCB 140 to be electrically connected selectively, the connection structure is simplified to reduce manufacturing costs. The production yield can be improved by shortening the manufacturing time.

As shown in FIGS. 2 and 3, each of the first and second

external connection terminals

125 and 145 has an array structure of one or more rows in plan view, and is arranged in the same column in a zigzag form. Arranged to have a symmetrical structure. Each of the first and second

external connection terminals

125 and 145 is preferably designed to be 10 to 30. 2 and 3 illustrate an example in which each of the first and second

external connection terminals

125 and 145 has an array structure of two columns.

In particular, when viewed in plan view, a plurality of first external connection terminals 125 are spaced apart from each other at a first interval d1, and a plurality of second external connection terminals 145 are equal to the first interval d1. Spaced apart from each other at a second interval d2. The first external connection terminal 125 and the second external connection terminal 145 are designed to be symmetrical with each other, and are connected to correspond to each other during the bonding process.

At this time, each of the first interval d1 and the second interval d2 is preferably designed to 50 ~ 200㎛. When each of the first interval d1 and the second interval d2 is less than 50 μm, the separation distance between the plurality of first external connection terminals 125 and the plurality of second external connection terminals 145 are different from each other. Too narrow a relationship may cause a problem of shorting between adjacent terminals in the soldering process. On the contrary, when each of the first interval d1 and the second interval d2 exceeds 200 μm, the plurality of first external connection terminals 125 and the plurality of second external connection terminals 145 are mutually different. Due to the fact that the liver is designed at more than necessary intervals, it is impossible to design a microcircuit, which may cause difficulty in implementing the integration.

On the other hand, the smaller the vertical gap between the hard PCB 120 and the FPCB 140, the better. This is, when attaching the FPCB 140 on the hard PCB 120, the hard PCB 120 and FPCB 140 This is to block the occurrence of gaps in between. Therefore, the vertical gap between the hard PCB 120 and the FPCB 140 is preferably designed to be 100 μm or less.

5 is an enlarged plan view illustrating a portion A of FIG. 3 and will be described with reference to FIG. 4.

4 and 5, the second external connection terminal 145 has a body portion 145a having a first width and a branch portion having a second width extending from the body portion 145a and narrower than the first width. 145b.

The solder discharge hole SH may be formed to penetrate the center of the second external connection terminal body 145a to be arranged in a zigzag form that is alternately arranged to correspond to the top and bottom of the second external connection terminal 145. Can be.

As in the present invention, when forming a solder discharge hole (SH) penetrating through the FPCB body 142 disposed at a position corresponding to the second external connection terminal 145 and the second external connection terminal 145, soldering During the process, the solder 160 interposed between the first external connection terminal 125 and the second external connection terminal 145 is smoothly discharged to the outside of the FPCB body 142 through the inside of the solder discharge hole SH. There is an advantage that the source can be prevented from occurring badly.

In particular, the solder discharge hole (SH) may be designed in any one shape selected from a circle, an ellipse, a polygon, etc. Among these, elliptical is most advantageous in terms of design processing or solder discharge efficiency. In this case, the size of the solder discharge hole SH is adjusted according to the thickness of the FPCB 140, and is interposed between the first and second

external connection terminals

125 and 145 according to the size of the solder discharge hole SH. The amount of solder 160 is determined.

Particularly, in the present invention, the solder discharge hole 160 is designed to be expanded to an optimal size, so that the soldering process can be performed in a state in which the space between the hard PCB 120 and the FPCB 140 is minimized. have.

That is, the solder discharge hole (SH) is preferably designed to have a width (W) of 0.3 ~ 0.5mm and a length (L) of 0.7 ~ 0.9mm, which is the case of the FPCB 140 having a thickness of 0.25mm or more, This is because it is possible to secure excellent solder discharge during the soldering process while minimizing the space at the junction between the first external connection terminal 125 and the second external connection terminal 145 to a minimum.

In this case, when the width W of the solder discharge hole SH is less than 0.3 mm or the length L is less than 0.7 mm, the solder interposed between the first and second external connection terminals 125 and 145 ( It is difficult to secure a sufficient area for the 160 to be discharged, which may cause a problem in which the solder 160 invades adjacent terminals and causes a short failure. On the contrary, when the width W of the solder discharge hole SH exceeds 0.5 mm or the length L exceeds 0.9 mm, the area of the solder discharge hole SH is excessively designed, which is limited. Since the area of the second external connection terminal 145 designed in the space becomes inevitably narrow, it may cause a problem that the reliability of the electrical conductivity of the second external connection terminal 145 is deteriorated.

6 is a plan view showing a two-layer circuit terminal portion of an FPCB made of a multilayer substrate having a triple layer structure, and FIG. 7 is a plan view showing a three-layer circuit terminal portion of an FPCB made of a multilayer substrate having a triple layer structure. 8 is a cross-sectional view taken along the line VIII-VIII ′ of FIG. 6.

6 to 8, the FPCB 140 according to the present invention may be formed of a multilayer substrate having three or more layers. In this case, the FPCB 140 including three or more multilayer substrates may further include an internal electrode pad 146, a through via 147, and a rearranged wiring 148.

The inner electrode pad 146 is formed inside the FPCB body 142. The internal electrode pads 146 may be formed on two and three layers of the multilayer substrate, respectively. The internal electrode pads 146 are disposed at the same positions as the second external connection terminals 145 and receive the same signal.

The through via 147 is formed to penetrate the second external connection terminal 145, the FPCB body 142, and the internal electrode pad 146, respectively, to pass through the second external connection terminal 145 and the internal electrode pad 146. It is an electrical connection. The through via 147 carries the role of the solder discharge hole SH.

The rearrangement wiring 148 is branched from the internal electrode pad 146 and the second external connection terminal 145, respectively, and serves to rearrange the electrical connections therebetween. The rearranged wiring 148 may be rearranged in a desired shape in a space between the internal electrode pads 146 and the second external connection terminals 145 in plan view.

Therefore, the FPCB 140 made of a multi-layered substrate having three or more layers may be able to design circuits between the inner layer and the outer layer in a different form through the rearrangement wiring 148, thereby freeing the position movement between the inner layer and the outer layer circuits. The area of the junction between the hard PCB 120 and the FPCB 140 may be more effectively utilized.

As described above, the soldering joint structure of the printed circuit board according to the exemplary embodiment of the present invention is a first external connection terminal of the hard PCB by soldering a hard PCB and a FPCB separated from each other without using a connection connector such as a socket. By performing direct bonding so that the second external connection terminal of the FPCB can be electrically connected selectively, the bonding structure can be simplified to reduce the manufacturing cost, and the production yield can be improved by shortening the manufacturing time.

In addition, the soldering joint structure of the printed circuit board according to the present invention, while extending the solder discharge hole to the optimum size, by arranging the external connection terminals in a zigzag form to ensure excellent solder discharge properties while utilizing a minimum space There is an advantage to this.

In addition, the soldering joint structure of the printed circuit board according to the present invention can be used to design a circuit between the inner layer and the outer layer in a different form by using three or more layers of multilayer substrate as FPCB, inner layer and outer layer circuits Free rearrangement of the liver allows more effective utilization of the area of the junction between the hard PCB and the FPCB.

Although the above has been described with reference to the embodiments of the present invention, various changes and modifications can be made at the level of those skilled in the art. Such changes and modifications can be said to belong to the present invention without departing from the scope of the technical idea provided by the present invention. Therefore, the scope of the present invention will be determined by the claims described below.

Claims

A hard PCB having a hard PCB body and a first external connection terminal disposed at one end of the hard PCB body;

An FPCB body having an FPCB body disposed to face the hard PCB body, a second external connection terminal disposed to overlap the first external connection terminal, and a solder discharge hole passing through the second external connection terminal; And

And a solder for directly connecting the first external connection terminal of the hard PCB to the second external connection terminal of the FPCB.

The solder discharge hole is a solder joint structure of a printed circuit board, characterized in that having a width of 0.3 ~ 0.5mm and a length of 0.7 ~ 0.9mm.
The method of claim 1,

The FPCB is

Soldering joint structure of a printed circuit board, characterized in that having a thickness of 0.25mm or more.
The method of claim 1,

Each of the first and second external connection terminals

A soldering joint structure of a printed circuit board having an array structure of one or more columns and arranged in a mutually zigzag form arranged in the same column to have a symmetrical structure.
The method of claim 1,

The solder discharge hole is

Soldering bonded structure of a printed circuit board, characterized in that it has a shape of any one of circular, oval and polygon.
The method of claim 1,

The solder discharge hole is

And a connection structure between the second external connection terminal and the FPCB body disposed at a position corresponding to the second external connection terminal.
The method of claim 1,

The second external connection terminal

A body portion having a first width and a branch portion extending from the body portion and having a second width narrower than the first width, wherein the solder discharge hole is formed to penetrate the center of the body portion; Junction structure.
The method of claim 1,

Each of the first and second external connection terminals

Soldering joint structure of a printed circuit board, characterized in that designed 10 to 30 pieces.
The method of claim 7, wherein

The first external connection terminal

The printed circuits are spaced apart from each other at a first interval, and the second external connection terminals are spaced apart from each other at a second interval equal to the first interval, and each of the first and second intervals is 50 to 200 μm. Bonding structure of the substrate.
The method of claim 1,

The FPCB is

A bonded structure of a printed circuit board, characterized in that the multi-layer substrate of three or more layers.
The method of claim 9,

The FPCB is

An internal electrode pad formed inside the FPCB body;

A through via formed to penetrate the second external connection terminal, the FPCB body, and the internal electrode pad, respectively to electrically connect the second external connection terminal and the internal electrode pad;

And a rearrangement wiring branched from the internal electrode pad and the second external connection terminal to rearrange electrical connections therebetween.
The method of claim 10,

The through via is

Bonding structure of a printed circuit board, characterized in that accompanied by the role of the solder discharge hole.
The method of claim 10,

The inner electrode pad is

A bonding structure of a printed circuit board, disposed at the same position as the second external connection terminal and receiving the same signal.
The method of claim 1,

The vertical gap between the hard PCB and the FPCB

Bonding structure of a printed circuit board, characterized in that it has a 100㎛ or less.
The method of claim 1,

The hard PCB

A main board for a mobile phone, wherein the FPCB is a bonded structure for a printed circuit board, characterized in that the substrate for a universal serial bus (USB) connector.