US 12,114,417 B2
Circuit board
Nobuo Tagashira, Tokyo (JP)
Assigned to SUMITOMO BAKELITE CO., LTD., Tokyo (JP)
Appl. No. 17/912,989
Filed by SUMITOMO BAKELITE CO., LTD., Tokyo (JP)
PCT Filed Feb. 19, 2021, PCT No. PCT/JP2021/006292
§ 371(c)(1), (2) Date Sep. 20, 2022,
PCT Pub. No. WO2021/192755, PCT Pub. Date Sep. 30, 2021.
Claims priority of application No. 2020-050891 (JP), filed on Mar. 23, 2020.
Prior Publication US 2023/0156905 A1, May 18, 2023
Int. Cl. H05K 1/02 (2006.01); H05K 1/09 (2006.01)
CPC H05K 1/0209 (2013.01) [H05K 1/09 (2013.01); H05K 2201/0355 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A circuit board comprising:
an insulating substrate; and
a circuit pattern of a metal formed on the insulating substrate in direct contact with the insulating substrate,
wherein a side surface of the circuit pattern has a region in which an angle formed by a surface of the insulating substrate and a tangential line at a middle portion in a height direction in a cross-sectional view perpendicular to an extending direction of the metal is 80 degrees or more and 100 degrees or less,
wherein in a case where a height of the circuit pattern is denoted by D, the side surface of the circuit pattern exhibits a straight line in the cross-sectional view perpendicular to the extending direction of the metal, in a height range of 0.4D or more and 0.6D or less in a perpendicular direction from the insulating substrate, and
wherein the side surface of the circuit pattern exhibits a trailing-tailed shape at an interface with the insulating substrate.