Wiring board connection method

1. A wiring board connection method which connects wiring boards each having a strip-shaped connection terminal for connecting with another substrate, the method comprising:

arranging a continuous conductive joint body (i) on adjacent connection terminals of one of the wiring boards, and (ii) in a space between the adjacent connection terminals on the one of the wiring boards;

aligning the wiring boards so that the connection terminals face each other with the conductive joint body interposed therebetween; and

bonding the connection terminals with each other by heating and then cooling the conductive joint body, wherein:

the conductive joint body is a material that generates air bubbles upon being heated;

a plurality of the connection terminals are provided in each of the wiring boards;

a recessed portion is formed on a surface of at least one of the connection terminals in at least one of the wiring boards, the surface being opposite to the connection terminal of another wiring board; and

when the connection terminals are bonded with each other, the conductive joint body is allowed to move so as to gather on the surfaces of the connection terminals where no recessed portions are formed.

2. The wiring board connection method according to claim 1 , wherein, the recessed portion is formed as a groove.

3. The wiring board connection method according to claim 2 , wherein, the groove is formed extending across the connection terminal.

4. The wiring board connection method according to claim 3 , wherein:

the groove has a depth reaching a surface of the wiring board; and

the connection terminal is separated by the groove and is intermittently formed on the surface of the wiring board.

5. The wiring board connection method according to claim 3 , wherein:

the groove has a depth not reaching a surface of the wiring board; and

the connection terminal is continuously formed on the surface of the wiring board.

6. The wiring board connection method according to claim 3 , wherein:

the groove is provided perpendicular to a longitudinal direction of the connection terminal; and

in the aligned state, the groove in one of the opposing connection terminals and a part of the other of the opposing connection terminals in which the groove is not formed face each other.

7. The wiring board connection method according to claim 6 , wherein:

the groove is formed in each of the opposing connection terminals;

the groove is provided on each of the connection terminals at equal spaces; and

in the aligned state, a center line of at least one of the grooves in one of the opposing connection terminals and a center line of the part of the other of the opposing connection terminals interposed between at least two of the grooves correspond to each other.

8. The wiring board connection method according to claim 6 , wherein,

a width of the groove is shorter than a length of the part of the other connection terminal.

9. The wiring board connection method according to claim 7 , wherein,

a width of the groove is shorter than a length of the part of the other connection terminal.

10. The wiring board connection method according to claim 1 , wherein:

the conductive joint body is a fluid containing conductive particles and an air bubble generating agent; and

the fluid contains a material that generates a gas as a result of boiling or thermally decomposing upon being heated.

11. The wiring board connection method according to claim 10 , wherein the alignment is conducted with a space between the wiring boards, the space being larger than a diameter of the conductive particles in the conductive joint body.

12. The wiring board connection method according to claim 1 , wherein the conductive joint body is an anisotropic conductive material.