摘要:
Processing workpieces such as semiconductor wafers or other materials with a laser includes selecting a target to process that corresponds to a target class associated with a predefined temporal pulse profile. At least one of the predefined temporal pulse profiles may be triangular. The target class may include, for example unpassivated electrically conductive links or other bare metal structures. Based on the target class associated with the selected target, a laser pulse is generated having a triangular temporal pulse profile. The generated laser pulse is used to process the selected structure.
摘要:
Processing workpieces such as semiconductor wafers or other materials with a laser includes selecting a target to process that corresponds to a target class associated with a predefined temporal pulse profile. At least one of the predefined temporal pulse profiles may be triangular. The target class may include, for example unpassivated electrically conductive links or other bare metal structures. Based on the target class associated with the selected target, a laser pulse is generated having a triangular temporal pulse profile. The generated laser pulse is used to process the selected structure.
摘要:
Processing workpieces such as semiconductor wafers or other materials with a laser includes selecting a target to process that corresponds to a target class associated with a predefined temporal pulse profile. The temporal pulse profile includes a first portion that defines a first time duration, and a second portion that defines a second time duration. A method includes generating a laser pulse based on laser system input parameters configured to shape the laser pulse according to the temporal pulse profile, detecting the generated laser pulse, comparing the generated laser pulse to the temporal pulse profile, and adjusting the laser system input parameters based on the comparison.
摘要:
A laser processing system provides a burst of ultrafast laser pulses having a selectively shaped burst envelope. A burst pulse laser includes a high repetition rate ultrafast laser to deliver a pulse train with each pulse in the train having an independently controlled amplitude. The respective amplitudes of each ultrafast pulse in a group define a “burst envelope.” In addition to independently controlling the amplitude of each ultrafast pulse within the burst envelope, the system may also provide selective control of spacing between each ultrafast pulse and/or the overall temporal width of the burst envelope. Thus, the system provides selective shaping of the burst envelope for particular laser processing applications.
摘要:
Systems and methods ablate electrically conductive links using laser pulses with optimized temporal power profiles and/or polarizations. In certain embodiments, the polarization property of a laser beam is set such that coupling between the laser beam and an electrically conductive link reduces the pulse energy required to ablate the electrically conductive link. In one such embodiment, the polarization is selected based on a depth of a target link structure. In another embodiment, the polarization changes as deeper material is removed from a target location. In addition, or in other embodiments, a first portion of a temporal power profile of a laser beam includes a rapid rise time to heat an upper portion of an electrically conductive link so as to form cracks in a passivation layer over upper corners of the electrically conductive link, without forming cracks at lower corners of the electrically conductive link.
摘要:
Tailored laser pulse shapes are used for processing workpieces. Laser dicing of semiconductor device wafers on die-attach film (DAF), for example, may use different tailored laser pulse shapes for scribing device layers down to a semiconductor substrate, dicing the semiconductor substrate, cutting the underlying DAF, and/or post processing of the upper die edges to increase die break strength. Different mono-shape laser pulse trains may be used for respective recipe steps or passes of a laser beam over a scribe line. In another embodiment, scribing a semiconductor device wafer includes only a single pass of a laser beam along a scribe line using a mixed-shape laser pulse train that includes at least two laser pulses that are different than one another. In addition, or in other embodiments, one or more tailored pulse shapes may be selected and provided to the workpiece on-the-fly. The selection may be based on sensor feedback.
摘要:
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.
摘要:
A laser processing system provides a burst of ultrafast laser pulses having a selectively shaped burst envelope. A burst pulse laser includes a high repetition rate ultrafast laser to deliver a pulse train with each pulse in the train having an independently controlled amplitude. The respective amplitudes of each ultrafast pulse in a group define a “burst envelope.” In addition to independently controlling the amplitude of each ultrafast pulse within the burst envelope, the system may also provide selective control of spacing between each ultrafast pulse and/or the overall temporal width of the burst envelope. Thus, the system provides selective shaping of the burst envelope for particular laser processing applications.
摘要:
An exemplary two-stroke internal combustion engine can comprise one or more cylinders comprising exhaust ports, one or more pistons configured to cyclically cover and uncover the exhaust ports during reciprocation of the pistons within the cylinders, and one or more rotary exhaust valves associated with each exhaust port. The exhaust valves can be configured to rotate around a valve axis that is substantially parallel to an axis of rotation of a crank shaft of the engine. Each exhaust valve at least partially obstructs the associated exhaust port during a portion of the exhaust valve's rotation about the valve axis while the associated exhaust port is at least partially uncovered by the associated piston, thereby trapping fresh charge within the combustion chamber.
摘要:
An exemplary two-stroke internal combustion engine can comprise one or more cylinders comprising exhaust ports, one or more pistons configured to cyclically cover and uncover the exhaust ports during reciprocation of the pistons within the cylinders, and one or more rotary exhaust valves associated with each exhaust port. The exhaust valves can be configured to rotate around a valve axis that is substantially parallel to an axis of rotation of a crank shaft of the engine. Each exhaust valve at least partially obstructs the associated exhaust port during a portion of the exhaust valve's rotation about the valve axis while the associated exhaust port is at least partially uncovered by the associated piston, thereby trapping fresh charge within the combustion chamber.