Electro Scientific Industries, Inc.

Brady Nilsen

David Martin Hemenway

Kelly Bruland

Brian W Baird

Ho Wai Lo

Clint R Vandergiessen

Keith Grant

Steve Stone

Mark Alan Unrath

Steve Swaringen

Yunlong Sun

Mark Kosmowski

Stephen Neal Swaringen

Bryan Conrad Bolt

Lei Sun

A Grey Lerner

Richard Pope

Methods and systems selectively irradiate structures on or within a semiconductor substrate using multiple laser beams. The structures may be laser-severable conductive links, and the purpose of the irradiation may be to sever selected links.

Methods and systems for semiconductor structure processing using multiple laser beam spots

Processing a workpiece with a laser includes generating laser pulses at a first pulse repetition frequency. The first pulse repetition frequency provides reference timing for coordination of a beam positioning system and one or more cooperating beam position compensation elements to align beam delivery coordinates relative to the workpiece. The method also includes, at a second pulse repetition frequency that is lower than the first pulse repetition frequency, selectively amplifying a subset of the laser pulses. The selection of the laser pulses included in the subset is based on the first pulse repetition frequency and position data received from the beam positioning system. The method further includes adjusting the beam delivery coordinates using the one or more cooperating beam position compensation elements so as to direct the amplified laser pulses to selected targets on the workpiece.

Photonic clock stabilized laser comb processing

Preferred embodiments of a purge gas port, laser beam attenuating input window, and laser shutter constitute subsystems of a UV laser optical system in which a laser beam is completely enclosed to reduce contamination of the optical system components. Purge gas is injected through multiple locations in a beam tube assembly to ensure that the optical component surfaces sensitive to contamination are in the flow path of the purge gas. The input window functions as a fixed level attenuator to limit photopolymerization of airborne molecules and particles. Periodically rotating optical elements asymmetrically in their holders reduces burn damage to the optics.

Optical component cleanliness and debris management in laser micromachining applications

A system determines relative positions of a semiconductor substrate and a plurality of laser beam spots on or within the semiconductor substrate in a machine for selectively irradiating structures on or within the substrate using a plurality of laser beams. The system comprises a laser source, first and second laser beam propagation paths, first and second reflection sensors, and a processor. The laser source produces at least the first and second laser beams, which propagate toward the substrate along the first and second propagation paths, respectively, which have respective first and second axes that intersects the substrate at respective first and second spots. The reflection sensors are positioned to detect reflection of the spots, as the spots moves relative to the substrate, thereby generating reflection signals. The processor is configured to determine, based on the reflection signals, positions of the spots on or within the substrate.

Systems and methods for distinguishing reflections of multiple laser beams for calibration for semiconductor structure processing

A laser processes a workpiece with laser pulses delivered at random time intervals and at substantially constant energy levels by characterizing the laser cavity discharge behavior and utilizing that information for adjusting dummy pulse time periods to compensate for the energy errors. Dummy pulses are laser pulses that are blocked from reaching a workpiece. A second way for providing constant pulse energies employs an AOM for varying amounts of laser energy passed to the workpiece. A third way of providing constant pulse energies entails extending the pulse period of selected pulses to allow additional laser cavity charging time whenever a dummy pulse is initiated.

High energy pulse suppression method

A method of suppressing distortion of a working laser beam directed for incidence on a target specimen presented for processing by a laser link processing system uses a spatial filter to remove stray light-induced distortion from the working laser beam.

Method of suppressing distortion of a working laser beam of a laser link processing system

A method and system decrease the amount of undesired laser radiation reaching a workpiece from a laser having a laser cavity and a Q-switch. The laser operates at any given time in one of at least two modes. In a first mode the laser emits pulses at a PRF (pulse repetition frequency) for selectively irradiating targets on or within a workpiece, and the pulses propagate along a propagation path to the workpiece. In a second mode less or no laser radiation desirably reaches the workpiece. The method is operable during the second mode. The method opens the Q switch more than the Q switch is open in the first mode, thereby limiting the amount of energy that builds up in the laser cavity and decreasing the peak energy of the laser radiation emitted in the second mode.

Method and system for preventing excessive energy build-up in a laser cavity

A laser () and an AOM () are pulsed at substantially regular and substantially similar constant high repetition rates to provide working laser outputs () with variable nonimpingement intervals () without sacrificing laser pulse-to-pulse energy stability. When a working laser output () is demanded, an RF pulse () is applied to the AOM () in coincidence with the laser output () to transmit it to a target. When no working laser output () is demanded, an RF pulse () is applied to the AOM () in noncoincidence with the laser output () so it gets blocked. So the average thermal loading on the AOM () remains substantially constant regardless of how randomly the working laser outputs () are demanded. The AOM () can also be used to control the energy of the working laser output () by controlling the power of the RF pulse () applied. When the RF power is changed, the RF duration () of the RF pulse () is modified to maintain the constant average RF power. Consistent loading on the AOM () eliminates deterioration of laser beam quality and laser beam pointing accuracy associated with thermal loading variation on the AOM () and is advantageous for applications such as IC chip link processing where stable working laser outputs () with variable output intervals () are needed.

Laser pulse picking employing controlled AOM loading

A Q-switched, diode-pumped, solid-state (DPSS) laser ( ) employs harmonic generation through nonlinear crystals ( ) to generate UV light ( ) for both link processing and target alignment. The type and geometry of the nonlinear crystals ( ) are selected, and their temperatures are precisely controlled, to produce focused spot sizes with excellent beam quality for severing of IC fuses. A fraction of the laser output ( ) can be utilized in a secondary target alignment system ( ). An imaging optics module ( ) may be employed to further enhance the shape quality of either or both of the secondary and primary beams. Each beam passes through a detection module ( ) that measures the incident and reflected light. The two beams pass through a common combiner to facilitate calibration and alignment of the beams and subsequent link processing.

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Beaverton, OR, United States of America

Brady Nilsen