Abstract: Detecting light from a detecting light source (122) is irradiated to a workpiece (1) and the reflected light is detected by a photosensor (126). At the same time, light resulting from emission of plume produced upon laser processing is also detected by the photosensor (126). A laser controller (26) binary-codes a detection signal from the photosensor (126) to provide a rectangular wave signal (TP) and, based on the rectangular wave signal (TP), generates a trigger signal (TP.sub.2) for oscillating a processing laser beam. At this time, the trigger signal (TP.sub.2) is fed back to generate a gate signal (GP) and, based on the gate signal (GP), the detection signal resulted from the emission of the plume is omitted in the gate circuit (245) to produce a trigger signal (TP.sub.G). This trigger signal (TP.sub.G) is given with a delay time (T.sub.D) to produce a trigger signal (TP.sub.1). The above trigger signal (TP.sub.2) is generated in synch with the trigger signal (TP.sub.1).

Abstract: The array condition of leads (3) is detected by a photoelectric detector (41), the detection signal is subjected to signal processing to determine the timing to oscillate a pulsed laser beam, and a laser beam axis (13C) is relatively moved at a speed (v.sub.0) with a work table (21) while oscillating a pulsed laser beam (13A), thereby cutting a dam bar (5). At this time, the longitudinal size of a spot (13B) of the pulsed laser beam (13A) is adjusted to be twice or more the width of the dam bar (5) by a longitudinal beam transformer (11a), the transverse size of the spot 13B is adjusted to be not less than 1/2 but not more than 4/5 of the length of the dam bar (5) by a transverse beam transformer (11b), and a beam rotator (11c) is appropriately operated to make the longitudinal direction of the spot (13B) substantially aligned with the longitudinal direction of the lead (3) so that the spot (13B) lies across the width (W.sub.1) of the dam bar (5).

Abstract: A lead frame fabricating method and a lead frame fabricating apparatus are provided which can easily fabricate lead frames of fine pattern at a high speed, can improve dimensional accuracy and quality of the lead frames after the fabrication, and can realize mass-production at a lower cost. To this end, when cutting a metal plate 1101 by irradiation of a laser beam, a laser beam 1011 emitted in the form of pulses and having a circular section is converted by a beam section transformer 1020 into a laser beam 1012 having an elongate elliptic section. The section of the laser beam 1012 is rotated on its optical axis by a beam rotating device 1030 so that the lengthwise direction of the section of the laser beam 1012 is coincident with the lengthwise direction of each of inner leads 1013. An optical axis of a laser beam 1015 is revolved along each of concentric paths 161 to 174 around the original optical axis given when the laser beam 1011 is emitted.

Abstract: An object of the present invention is to, in methods of processing metal plates and lead frames, enable workpieces to be finely processed into a satisfactory configuration with high dimensional accuracy without suffering the effect of heat produced under irradiation of a laser beam. According to the present invention, resist films (1) are first coated on both surfaces of a metal plate (1), and a laser beam (202) is then irradiated to the metal plate (101) from surfaces of the resist films (1) to form a multiplicity of discontinuous through holes (3) in line, while leaving joints (6) as not-processed portions between the adjacent through holes (3). Openings (2) formed in each resist film (1) by the laser cutting are joined with each other to serve as an etching pattern. Next, etching is carried out to etch side walls (6) defining the through holes and also to remove the joints (6), thereby interconnecting the through holes (3) formed in line to form a gap (303a) of a desired shape.

Abstract: In a method for forming a lead frame (1) from a metallic plate, a metallic plate (11) is first etched to form outer leads (4) and outer portions (3b) of inner leads of the lead frame (1). Inner portions (3a) of the inner leads (3) are then laser-cut under the condition that a joint portion (7) is left so as to interconnect the inner leads (3) at their distal ends. Mechanical surface treatment and chemical surface treatment are then carried out to remove dross (10), spatters (9) and oxide films deposited during the laser cutting. Inner areas of the inner leads (3) connected to respective terminals of a semiconductor chip are then plated with gold to form plated terminal portions (3A). Subsequently, the region of the lead frame other than the outer leads (4) is coated with a protective film for solder plating and the outer leads (4) are plated with solder.