US 11,706,877 B2
Composite wiring substrate and semiconductor device
Shota Miki, Nagano (JP); Koyuki Kawakami, Nagano (JP); Kiyoshi Oi, Nagano (JP); Kei Murayama, Nagano (JP); and Mitsuhiro Aizawa, Nagano (JP)
Assigned to SHINKO ELECTRIC INDUSTRIES CO., LTD., Nagano (JP)
Filed by SHINKO ELECTRIC INDUSTRIES CO., LTD., Nagano (JP)
Filed on May 2, 2022, as Appl. No. 17/661,585.
Claims priority of application No. 2021-079986 (JP), filed on May 10, 2021.
Prior Publication US 2022/0361342 A1, Nov. 10, 2022
Int. Cl. H05K 3/34 (2006.01); H01L 23/498 (2006.01); H05K 1/11 (2006.01); H05K 3/46 (2006.01)
CPC H05K 3/3463 (2013.01) [H01L 23/49811 (2013.01); H01L 23/49822 (2013.01); H05K 1/113 (2013.01); H05K 3/4644 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A composite wiring substrate comprising:
a first wiring substrate including a first connection terminal;
a second wiring substrate including a second connection terminal facing the first connection terminal; and
a joint material joining the first connection terminal and the second connection terminal,
wherein a first outline of the first connection terminal is inside a second outline of the second connection terminal in a plan view, and
the joint material includes
a first portion famed of an intermetallic alloy of copper and tin, and contacting each of the first connection terminal and the second connection terminal, and
a second portion formed of an alloy of tin and bismuth, and including a portion between the first outline and the second outline in the plan view, the second portion containing the bismuth at a higher concentration than in a eutectic composition of a tin-bismuth alloy, the second portion being separated from the second connection terminal.