Sumitomo Metal Mining Company, Ltd.

Sh Materials Co., Ltd.

Possehl Sumiko Electronics Singapore Pte Ltd.

Yoichiro Hamada

Shigeru Hosomomi

A manufacturing method of a substrate for a semiconductor package includes a resist layer forming step to form a resist layer on a surface of a conductive substrate; an exposure step to expose the resist layer using a glass mask with a mask pattern including a transmission area, a light shielding area, and an intermediate transmission area, wherein transmittance of the intermediate transmission area is lower than that of the transmission area and is higher than that of the light shielding area; a development step to form a resist pattern including a hollow with a side shape including a slope part decreasing in hollow circumference as the hollow circumference approaches the substrate; and a plating step to plate on an exposed area to form a metal layer with a side shape including a slope part decreasing in circumference as the circumference approaches the substrate.

Manufacturing method of substrate for a semiconductor package, manufacturing method of semiconductor package, substrate for a semiconductor package and semiconductor package

A process for producing lead frames having lead tips with a minimum of side etching includes the steps of coating a metal lead frame substrate with a first photosensitive film, patterning the first photosensitive film, developing the patterned first photosensitive film, partially etching the metal surface of the lead-frame substrate beneath the developed patterned first photosensitive film, coating the partially etched metal surface with a positive second photosensitive, exposing the positive second photosensitive film to light passing through the developed first photosensitive film, developing the exposed second photosensitive film, performing fine etching through the developed second photosensitive film to a desired depth at least once, and removing the first and second photosensitive films.

Growing community of inventors

Tokyo, Japan

Yoichiro Hamada