METAL SHEET PROCESSING METHOD AND LEAD FRAME PROCESSING METHOD, AND LEAD FRAME AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD AND SEMICONDUCTOR DEVICE

摘要

An object of this invention is to provide a metal sheet processing method and a lead frame processing method which are capable of processing a work to an excellent shape finely with a high dimensional accuracy without being influenced by heat input due to the irradiation of a laser beam. According to the present invention, a metal sheet (101) is coated at both surfaces thereof with photoresist films (1) first, and a laser beam (202) is then applied to the metal sheet (101) through the outer surface of the photoresist film (1) so as to form a plurality of discontinuous through bores (3) in rows with joint portions (6) as unprocessed portions left among the through bores (3). The opened portions (2) formed by the laser beam processing of the photoresist film (1) extend continuously to serve as an etching pattern. The surrounding wall portions (6) are then subjected to etching to remove the same and connect together the through bores (3) formed in rows, whereby clearances (303a) of a predetermined shape are formed. Instead of forming the through bores (3) and joint portions (6) in the metal sheet (101), the steps of forming non-through bores (51) in the metal sheet (101) with joint portions (52) left as unprocessed portions in their bottoms, and then subjecting the resultant product to etching may be taken.