초록 ▼

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 (v0) with a work table (21) while oscillating a p

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 (v0) 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 1/2but not more than 4/5of 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 (W1) of the dam bar (5). As a result, the configuration after cutting the dam bar (5) becomes highly accurate and satisfactory.

대표청구항 ▼

A dam bar cutting apparatus for irradiating a pulsed laser beam (13A) to dam bars (5) of a lead frame (2) in a semiconductor device (1) and cutting said dam bars (5) successively, said dam bar cutting apparatus comprising a laser oscillator (10) for oscillating a pulsed laser beam (10A), a cutting o

A dam bar cutting apparatus for irradiating a pulsed laser beam (13A) to dam bars (5) of a lead frame (2) in a semiconductor device (1) and cutting said dam bars (5) successively, said dam bar cutting apparatus comprising a laser oscillator (10) for oscillating a pulsed laser beam (10A), a cutting optical system (14, 16) for guiding said pulsed laser beam (10A) to the cut position of a workpiece, a work nozzle (13) for emitting said pulsed laser beam (13A) guided by said cutting optical system (14, 16) therethrough and being provided at its tip end with an opening (13a) for ejecting assist gas (17A) therethrough, carriage means (21) for relatively moving an optical axis (13C) of said pulsed laser beam (13A) at a constant speed with respect to said workpiece, detection light generating means (44) for irradiating detection light (44A) to each of said dam bars (5) to be cut and thereabout on said lead frame (2), light detecting means (41) for receiving the detection light (41A) reflected by said lead frame (2) and generating a corresponding detection signal, and control means (30) for determining the timing to irradiate said pulsed laser beam (13A) based on the detection signal from said light detecting means (41) and controlling said laser oscillator (10) so that said pulsed laser beam (13A) is irradiated to a predetermined position on said dam bar (5), wherein said dam bar cutting apparatus further comprises: longitudinal beam transforming means (11a) for transforming said pulsed laser beam (10A) oscillated from said laser oscillator (10) into a pulsed laser beam (10B) having an oblong cross-sectional shape so that the longitudinal size (W4) of a spot (13B) of said pulsed laser beam (10A) on said dam bar (5) is twice or more the width (W1) of said dam bar (5), transverse beam transforming means (11b) for transforming said pulsed laser beam (10B) so that the transverse size (W3) of said spot (13B) of said pulsed laser beam (10B) on said dam bar (5) is not less than 1/2but not more than 4/5of the length (W2) of said dam bar (5), and beam rotating means (11c) for rotatively displacing said spot (13B) about the optical axis (13C) of said pulsed laser beam (13A).