Abstract: Numerous embodiments are disclosed. Many of which relate to methods of forming vias in workpieces such as printed circuit boards. Some embodiments relates techniques for indirectly ablating a region of an electrical conductor structure of, for example, a printed circuit board by spatially distributing laser energy throughout the region before the electrical conductor is indirectly ablated. Other embodiments relate to techniques for temporally-dividing laser pulses, modulating the optical power within laser pulses, and the like.

Abstract: A method of processing a workpiece having a first surface and a second surface opposite the first surface includes: generating a first beam of laser pulses having a pulse duration less than 200 ps at a pulse repetition rate greater than 500 kHz, directing the first beam of laser pulses along a beam axis intersecting the workpiece, and scanning the beam axis along a processing trajectory. The beam axis is scanned such that consecutively-directed laser pulses impinge upon the workpiece at a non-zero bite size to form a feature at the first surface of the workpiece. One or more parameters such as bite size, pulse duration, pulse repetition rate, laser pulse spot size and laser pulse energy is selected to ensure that the feature has a processed workpiece surface with a mean surface roughness (Ra) of less than or equal to 1.0 ?m.

Abstract: Employing laser scanning directions (20) that are oblique to and against a predominant gas flow direction (25) equalize the quality and waviness characteristics of orthogonal scribe lines (26) made by the laser scans. Positioning and sequence of multiple scan passes to form a feature wider than the width of a scribe line (26) can be controlled to enhance quality and waviness characteristics of the edges of the feature.

Abstract: Employing laser scanning directions (20) that are oblique to and against a predominant gas flow direction (25) equalize the quality and waviness characteristics of orthogonal scribe lines (26) made by the laser scans. Positioning and sequence of multiple scan passes to form a feature wider than the width of a scribe line (26) can be controlled to enhance quality and waviness characteristics of the edges of the feature.

Abstract: A method of forming an aperture (e.g., a through via, a blind via, a trench, an alignment feature, etc.) within a substrate includes irradiating a substrate with a laser beam to form a laser-machined feature having a sidewall. The laser-machined feature is then processed to change at least one characteristic (e.g., the sidewall surface roughness, diameter, taper, aspect ratio, cross-sectional profile, etc.) of the laser-machined feature. The laser-machined feature can be processed to form the aperture by performing an isotropic wet-etch process employing an etchant solution containing HNO3, HF and, optionally acetic acid.

Abstract: An improved method for singulation of electronic substrates into dice uses a laser to first form cuts in the substrate and then chamfers the edges of the cuts by altering the laser parameters. The chamfers increase die break strength by reducing the residual damage and removes debris caused by the initial laser cut without requiring additional process steps, additional equipment or consumable supplies.

Abstract: An improved method for singulation of electronic substrates into dice uses a laser to first form cuts in the substrate and then chamfers the edges of the cuts by altering the laser parameters. The chamfers increase die break strength by reducing the residual damage and removes debris caused by the initial laser cut without requiring additional process steps, additional equipment or consumable supplies.

Abstract: A method of forming an aperture (e.g., a through via, a blind via, a trench, an alignment feature, etc.) within a substrate includes irradiating a substrate with a laser beam to form a laser-machined feature having a sidewall. The laser-machined feature is then processed to change at least one characteristic (e.g., the sidewall surface roughness, diameter, taper, aspect ratio, cross-sectional profile, etc.) of the laser-machined feature. The laser-machined feature can be processed to form the aperture by performing an isotropic wet-etch process employing an etchant solution containing HNO3, HF and, optionally acetic acid.

Abstract: An improved method for singulation of electronic substrates into dice uses a laser to first form cuts in the substrate and then chamfers the edges of the cuts by altering the laser parameters. The chamfers increase die break strength by reducing the residual damage and removes debris caused by the initial laser cut without requiring additional process steps, additional equipment or consumable supplies.

Abstract: Laser singulation of electronic devices from semiconductor substrates including wafers is performed using up to 3 lasers from 2 wavelength ranges. Using up to 3 lasers from 2 wavelength ranges permits laser singulation of wafers held by die attach film while avoiding problems caused by single-wavelength dicing. In particular, using up to 3 lasers from 2 wavelength ranges permits efficient dicing of semiconductor wafers while avoiding debris and thermal problems associated with laser processing die attach tape.

Abstract: An improved method for singulation of electronic substrates into dice uses a laser to first form cuts in the substrate and then chamfers the edges of the cuts by altering the laser parameters. The chamfers increase die break strength by reducing the residual damage and removes debris caused by the initial laser cut without requiring additional process steps, additional equipment or consumable supplies.