| 摘要 |
PURPOSE: To reduce a stress of a track by allowing a ball to connect to tracks of an electronic circuit having a portion not sticking to the electronic circuit at a location of a connection region and its surroundings. CONSTITUTION: An electronic circuit 1 is disposed on a ball 10 fused and solidified, and the ball 10 is refused without bring close electronic circuits 1, 2 to each other. A connection of the electronic circuits 1, 2 is immediately established by resolidifying the ball 10. Preferably, a connection region 9 is made small to obtain the most spherical possible ball 10. Further, a width of a track 5 is made preferably smaller than a diameter of the ball 10 (e.g. 4-20 micron each). An adhering sub-film 7 does not exist in a non-adhesive portion of the track 5 extending under the ball 10. Accordingly, the non-adhesive portion does not adhere to connection faces 3, 4. Thereby, a stress resulting from volume expansion of the track 5 can be made small. |
