US Patent No. 10,143,088

METHOD FOR PRODUCING WIRED CIRCUIT BOARD


Patent No. 10,143,088
Issue Date November 27, 2018
Title Method For Producing Wired Circuit Board
Inventorship Yuu Sugimoto, Osaka (JP)
Hiroyuki Tanabe, Osaka (JP)
Assignee NITTO DENKO CORPORATION, Osaka (JP)

Claim of US Patent No. 10,143,088

1. A method for producing a wired circuit board including an insulating layer and a conductive pattern provided on one side face in a thickness direction of the insulating layer, the method including the steps of:a step (1), in which the insulating layer is provided, the insulating layer having the one side face including a flat face and an inclined face, the inclined face being inclined from the flat face toward the one side in the thickness direction,
a step (2), in which a metal thin film is provided on the flat face and the inclined face of the insulating layer,
a step (3), in which a photoresist is provided on the metal thin film,
a step (4), in which a photomask is disposed so that in the photoresist, a to-be-portion where the conductive pattern is to be provided and which is provided on the flat face is shielded from light and a portion other than the to-be-portion in the photoresist is not shielded, wherein the portion other than the to-be-portion in the photoresist includes, when projected in the thickness direction, the inclined face, and the photoresist is exposed to light through the photomask,
a step (5), in which the to-be-portion of the photoresist shielded from light by the photomask is removed to expose the metal thin film corresponding to the to-be-portion, and
a step (6), in which the conductive pattern is provided on the metal thin film exposed from the photoresist,
wherein when exposing the photoresist in the step (4), reflection is caused by the metal thin film positioned above the inclined face to reduce light toward the to-be-portion on the flat face.