JP4070093B2 - Circuit board stacking connection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of stacking and connecting a plurality of circuit boards at intervals, and more particularly to a method suitable for stacking and connecting circuit boards on which electronic components are already mounted.
[0002]
[Prior art]
Two circuit boards on which electronic components are already mounted are arranged opposite to each other, and as a means of connecting with a gap, a connection pin is erected on one circuit board by soldering, and the other circuit is connected to the tip of this connection pin. It is conceivable to solder the board.
[0003]
[Problems to be solved by the invention]
However, in flow soldering, only connection pins near the outer periphery of the circuit board can be soldered. The reason is that if flow soldering is performed at the center of the circuit board, the electronic component already mounted is immersed in the solder bath, and the electronic component is damaged. In reflow soldering, cream solder needs to be printed. However, when an electronic component is already mounted on a circuit board, the solder cannot be printed because there are large irregularities on the surface.
[0004]
An object of the present invention is to provide a method for stacking and connecting circuit boards that solves the above-described problems.
[0005]
[Means for Solving the Problems]
In one circuit board stacking connection method according to the present invention, a connection pin is set up at a connection position with an upper circuit board of a lower circuit board, and an upper end portion of the connection pin is formed on the upper surface of the lower circuit board on which the connection pin is set up. A printing stand is formed so as to be exposed, cream solder is printed on the upper surface of the printing stand so as to be in contact with the connection pins, and an upper circuit board is placed on the printing stand, and then heated to connect the connection pins. The upper layer circuit board is soldered.
[0006]
Another circuit board laminated connection method according to the present invention is such that a connection pin having a stopper in the middle in the height direction is set up at a position to be connected to the upper circuit board of the lower circuit board, and the pin is positioned at a position corresponding to the connection pin. Prepare a printed sheet with holes, print cream solder at the position corresponding to the pin holes on the upper surface of the printed sheet, and overlay the upper circuit board on this printed sheet so that the pin holes on both sides match. The superposed product is placed on the stopper of the connection pin and then heated to solder the connection pin and the upper circuit board.
[0007]
Another circuit board laminated connection method according to the present invention is such that a connection pin having a stopper in the middle in the height direction is set up at a position to be connected to the upper circuit board of the lower circuit board, and the pin is positioned at a position corresponding to the connection pin. A printed sheet having holes formed therein is prepared, and cream solder is printed at a position corresponding to the pin hole on the upper surface of the printed sheet, and the printed sheet is placed on the stopper of the connection pin, and further on the printed sheet. After the upper circuit board is mounted, the connection pins and the upper circuit board are soldered by heating.
[0008]
In any of the stacked connection methods, it is preferable that the printing stand or the printed sheet is removed after the connection pins and the upper circuit board are soldered.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
1A to 1E show an embodiment of the present invention. In the figure, 10 is a lower circuit board, 12 is an upper circuit board, and 14 is a connection pin. The lower circuit board 10 and the upper circuit board 12 have electronic components (not shown) mounted on both sides or one side.
[0011]
In this embodiment, first, as shown in (A), the connection pins 14 are set up at the connection positions of the lower circuit board 10 and the upper circuit board. The connection pins 14 are all the same height. A pin hole (through hole) is formed in the lower circuit board 10 at a position where the connection pin 14 is erected, and the connection pin 14 is soldered to the lower circuit board 10 with the lower end portion inserted into the pin hole. .
[0012]
Next, a printing stand 16 for solder printing is formed on the lower circuit board 10 as shown in FIG. The printing stand 16 is formed to a thickness such that the upper end of the connection pin 14 is exposed on the upper surface. Further, a recess 18 is formed on the upper surface of the printing stand 16 to accommodate electronic components mounted on the lower surface of the upper circuit board 12. The area other than the recess 18 on the upper surface of the printing table 16 is flat.
[0013]
Next, a solder printing screen (not shown) is placed on the printing table 16, and the cream solder 20 is printed so as to surround (or cover) the upper ends of the connection pins 14 as shown in (C). To do. Next, as shown in (D), the upper circuit board 12 is placed on the printing table 16. The upper circuit board 12 is previously formed with pin holes into which the upper ends of the connection pins 14 are inserted. In this state, the whole is put in a reflow furnace, heated, and then cooled, the connection pin 14 and the upper circuit board 12 are soldered, and the lower circuit board 10 and the upper circuit board 12 are electrically connected by the connection pin 14. It becomes the state.
[0014]
Thereafter, when the printing stand 16 is removed, a two-layer type laminated circuit board as shown in (E) can be obtained. Since the printing table 16 is preferably removed after soldering, a material that can be easily removed after soldering may be used. As such a material, it is preferable to use, for example, an organic material that can be dissolved with an appropriate solvent, or a powder that can be hardened into a flat plate shape and easily collapses when heated.
[0015]
2A to 2D show another embodiment of the present invention. In this embodiment, first, a connection pin 14 having a stopper 22 in the middle in the height direction is erected on the lower circuit board 10 as shown in FIG. All the connection pins 14 have the same height, and the stoppers 22 have the same height.
[0016]
Next, a print sheet 24 as shown in FIG. This printed sheet 24 has pin holes (not shown) through which the connection pins 14 are passed at positions corresponding to the respective connection pins, and is opened at positions corresponding to electronic components mounted on the lower surface of the upper circuit board 12. And solder cream 20 is printed on the upper surface so as to close the hole (or surround the hole). Since the upper surface of the printing sheet 24 is flat, the printing of the cream solder 20 is easy.
[0017]
Next, the upper circuit board 12 is overlaid on the printed sheet 24 so that both pin holes (28 is a pin hole of the upper circuit board 12) coincide. Then, the electronic components on the lower surface of the upper circuit board 12 enter the opening 26 of the printed sheet 24, and the cream solder 20 is sandwiched between the printed sheet 24 and the upper circuit board 12. In this state, the printing sheet 24 is placed on the stopper 22 so that the upper end portions of the connection pins 14 are inserted into the pin holes of the printing sheet 24 and the upper circuit board 12.
[0018]
Then, it becomes like (C). In this state, the whole was put in a reflow furnace, heated, and then cooled, the connection pin 14 and the upper circuit board 12 were soldered, and the lower circuit board 10 and the upper circuit board 12 were electrically connected by the connection pin 14 It becomes a state. Even if it remains as it is, there is no problem in practical use. However, since the printing sheet 24 is unnecessary, if it is removed, a two-layered laminated circuit board as shown in (D) can be obtained. In order to facilitate removal of the printed sheet 24 after soldering, a thin and easily broken material such as paper may be used for the printed sheet 24.
[0019]
According to this embodiment, even if electronic components are mounted on the upper surface of the lower circuit board 10 and the lower surface of the upper circuit board 12, the lower circuit board 10 and the upper circuit board 12 can be connected without any trouble.
[0020]
In the embodiment of FIG. 2, the upper circuit board 12 is overlaid on the print sheet 24 and the superposition is placed on the stoppers 22 of the connection pins. May be placed on the stopper 22 of the connection pin, and the upper circuit board 12 may be placed thereon. However, in this case, it is necessary to use a printing sheet 24 that has a certain degree of rigidity so as not to bend when placed on the stopper 22.
[0021]
In each of the embodiments described above, the case of assembling a two-layered laminated circuit board has been described. However, a laminated circuit board having three or more layers can be similarly assembled.
[0022]
【The invention's effect】
As described above, according to the present invention, by providing a printing stand or a printing sheet, printing of cream solder and circuit board laminated connection by reflow soldering are possible, so that not only the peripheral part of the circuit board, A connection pin can be set up also in the central portion, and a highly flexible laminated connection can be performed without restricting the connection location.
[Brief description of the drawings]
1A to 1E are perspective views showing an embodiment of a circuit board laminated connection method according to the present invention in the order of steps;
FIGS. 2A to 2D are perspective views showing another embodiment of a circuit board laminated connection method according to the present invention in the order of steps;
[Explanation of symbols]
10: Lower circuit board
12: Upper circuit board
14: Connection pin
16: Printing stand
18: Recess
20: Cream solder
22: Stopper
24: Printing sheet
26: Opening
28: Pin hole

Claims (5)

A connection board is set up at a connection position with the upper circuit board of the lower circuit board, and a printing stand is formed on the lower circuit board on which the connection pin is set up so that the upper end of the connection pin is exposed on the upper surface. A solder paste is printed on the upper surface of the printed circuit board so as to come into contact with the connection pins, the upper circuit board is placed on the printing table, and then heated to solder the connection pins and the upper circuit board. Layered connection method for substrates. 2. The method for stacking and connecting circuit boards according to claim 1, wherein the printing stand is removed after the connection pins and the upper circuit board are soldered. A connection sheet having a stopper in the middle in the height direction is set up at a position where it is connected to the upper circuit board of the lower circuit board, and a printed sheet having pin holes formed at positions corresponding to the connection pins is prepared. Cream solder is printed at a position corresponding to the pin hole on the upper surface, and the upper circuit board is overlaid on the printed sheet so that both pin holes coincide with each other, and the superposed one is placed on the stopper of the connection pin. A circuit board laminated connection method, wherein the connection pins and the upper circuit board are soldered after being placed and heated. A connection sheet having a stopper in the middle in the height direction is set up at a position where it is connected to the upper circuit board of the lower circuit board, and a printed sheet having pin holes formed at positions corresponding to the connection pins is prepared. Cream solder is printed at a position corresponding to the pin hole on the upper surface, and this printed sheet is placed on the stopper of the connection pin, and further, an upper circuit board is placed on the printed sheet, and then heated to connect. A method of laminating and connecting circuit boards, characterized by soldering pins and an upper circuit board. 5. The method for stacking and connecting circuit boards according to claim 3, wherein the printed sheet is removed after the connection pins and the upper circuit board are soldered.

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