Tip/chip die electronic parts enclosing mount

摘要

PROBLEM TO BE SOLVED: To sufficiently keep the strength as a carrier even when it is treated in a severe use condition, by making the thickness of a multi-ply board and the coefficient of variation of paper weight less than a specified value and making the smoothness on the surface smaller than a specified value through a smoothness tester. SOLUTION: Peeling in a severe use condition like the traverse treatment can be prevented by making larger than 1.250% the coefficient of variation of paper weight of a containing base board which is a multi-ply board thicker than 0.75mm having a high possibility of exfoliation by a rubbing (shifting) load. A cover tape is stuck to the containing base board at both front surface (top tape) and rear face (bottom tape) of the paper. A favorable adhesive and peelable properties are required for the top tape when chip parts are taken out in the end users. And hence, it is necessary that the smoothness of the paper surface of the containing base board is less than 70cm through a smoothness tester.