Patent•
Beam shaping and projection imaging with solid state uv gaussian beam to form vias
26 May 2000-
TL;DR: In this article, a diode-pumped solid-state laser (52) of a laser system (50) provides ultraviolet Gaussian output (54) that is converted by a diffractive optical element (90) into shaped output (94) having a uniform irradiance profile.
Abstract: A diode-pumped, solid-state laser (52) of a laser system (50) provides ultraviolet Gaussian output (54) that is converted by a diffractive optical element (90) into shaped output (94) having a uniform irradiance profile. A high percentage of the shaped output (94) is focused through an aperture of a mask (98) to provide imaged shaped output (118). The laser system (50) facilitates a method for increasing the throughput of a via drilling process over that available with an analogous clipped Gaussian laser system. This method is particularly advantageous for drilling blind vias (20b) that have better edge, bottom, and taper qualities than those produced by a clipped Gaussian laser system. An alternative laser system (150) employs a pair of beam diverting galvanometer mirrors (152, 154) that directs the Gaussian output around a shaped imaging system (70) that includes a diffractive optical element (90) and a mask (98). Laser system (150) provides a user with the option of using either a Gaussian output or an imaged shaped output (118).
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Patent•
19 Dec 2000
TL;DR: In this article, an energy-efficient method and system for processing target material such as microstructures in a microscopic region without causing undesirable changes in electrical and/or physical characteristics of material surrounding the target material is provided.
Abstract: An energy-efficient method and system for processing target material such as microstructures in a microscopic region without causing undesirable changes in electrical and/or physical characteristics of material surrounding the target material is provided. The system includes a controller for generating a processing control signal and a signal generator for generating a modulated drive waveform based on the processing control signal. The waveform has a sub-nanosecond rise time. The system also includes a gain-switched, pulsed semiconductor seed laser for generating a laser pulse train at a repetition rate. The drive waveform pumps the laser so that each pulse of the pulse train has a predetermined shape. Further, the system includes a laser amplifier for optically amplifying the pulse train to obtain an amplified pulse train without significantly changing the predetermined shape of the pulses. The amplified pulses have little distortion and have substantially the same relative temporal power distribution as the original pulse train from the laser. Each of the amplified pulses has a substantially square temporal power density distribution, a sharp rise time, a pulse duration and a fall time. The system further includes a beam delivery and focusing subsystem for delivering and focusing at least a portion of the amplified pulse train onto the target material. The rise time (less than about 1 ns) is fast enough to efficiently couple laser energy to the target material, the pulse duration (typically 2-10 ns) is sufficient to process the target material, and the fall time (a few ns) is rapid enough to prevent the undesirable changes to the material surrounding the target material.
234 citations
Patent•
25 Jan 2006
TL;DR: In this paper, a laser beam processing machine comprising a path distribution means for distributing a pulse laser beam oscillated by pulse laserbeam oscillation means to a first path and a second path alternately, and one laser beam that passes through one of the paths and is converged by one condensing lens and the other laser beam is applied at different focusing points which have been displaced from each other in the direction of the optical axis.
Abstract: A laser beam processing machine comprising a path distribution means for distributing a pulse laser beam oscillated by pulse laser beam oscillation means to a first path and a second path alternately, and one laser beam that passes through one of the paths and is converged by one condensing lens and the other laser beam that passes through the other path and is converged by the condensing lens are applied at different focusing points which have been displaced from each other in the direction of the optical axis, alternately with a time lag between them.
212 citations
Patent•
07 Jun 2002TL;DR: In this paper, a long cut path is divided into short segments, from about 10 µm to 1 mm, and the laser output is scanned within a first short segment for a predetermined number of passes before being moved to and scanned within another short segment (122) for a certain time interval.
Abstract: UV laser cutting throughput through silicon and like materials is improved by dividing a long cut path (112) into short segments (122), from about 10 µm to 1 mm. The laser output (32) is scanned within a first short segment (122) for a predetermined number of passes before being moved to and scanned within a second short segment (122) for a predetermined number of passes. The bite size, segment size (126), and segment overlap (136) can be manipulated to minimize the amount and type of trench backfill. Real-time monitoring is employed to reduce rescanning portions of the cut path (112) where the cut is already completed. Polarization direction of the laser output (32) is also correlated with the cutting direction to further enhance throughput. This technique can be employed to cut a variety of materials with a variety of different lasers and wavelengths.
208 citations
Patent•
25 Feb 2004
TL;DR: In this paper, a fundamental wave is used without putting laser light into a non linear optical element, and laser annealing is conducted by irradiating a semiconductor thin film with pulsed laser light having a high repetition rate.
Abstract: In conducting laser annealing using a CW laser or a quasi-CW laser, productivity is not high as compared with an excimer laser and thus, it is necessary to further enhance productivity. According to the present invention, a fundamental wave is used without putting laser light into a non linear optical element, and laser annealing is conducted by irradiating a semiconductor thin film with pulsed laser light having a high repetition rate. A laser oscillator having a high output power can be used for laser annealing, since a non linear optical element is not used and thus light is not converted to a harmonic. Therefore, the width of a region having large grain crystals that is formed by scanning once can be increased, and thus the productivity can be enhanced dramatically.
188 citations
Patent•
15 Jun 2005
TL;DR: In this paper, a laser irradiation apparatus for homogenously crystallized films is described, where the energy intensity of an irradiation beam in forward and backward directions of the irradiation is varied in accordance with the scanning direction.
Abstract: It is an object of the present invention to provide a laser irradiation apparatus which can manufacture a homogenously crystallized film by varying the energy intensity of an irradiation beam in forward and backward directions of the irradiation. A laser irradiation apparatus of the present invention comprises a laser oscillator and means for varying beam intensity wherein a laser beam is obliquely incident into the irradiation surface, the laser beam is scanned relative to the irradiation surface, and the beam intensity is varied in accordance with the scanning direction. Further, the laser oscillator is a continuous wave solid-state laser, gas laser, or metal laser. A pulsed laser having a repetition frequency of 10 MHz or more can also be used.
174 citations
References
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Patent•
21 May 1997
TL;DR: In this article, a beam expander is applied to render a large mode waist and an improved beam divergence so as to greatly reduce the insertion losses for intracavity optical elements (17, 18 or 44 ).
Abstract: Key technologies have been developed in realizing single longitudinal mode CW operation with a regular standing-wave cavity for intracavity frequency doubling and intracavity frequency conversions, so as to produce all solid-state, true cw devices with operation over wide spectral ranges including green, blue and UV. In one method, a beam expander ( 23 or 41 ) is applied to render a large mode waist and an improved beam divergence so as to greatly reduce the insertion losses for intracavity optical elements ( 17, 18 or 44 ). In another method, when spatial hole burning effect is minimized by using a pump head ( 12 ) with a thin gain zone ( 2 ), then a low resolving-power spectral filter with low loss can be utilized. In addition, several novel optical multipass constructions, typically by use of total-internal-reflection, have also been devised for pumping laser chips, laser rods, laser slabs, and for the use of multipass optical amplifier and pumping fiber lasers.
59 citations
Patent•
04 Oct 1994
TL;DR: In this article, a high resolution, deep UV beam delivery system for exposing a surface, directly or through a mask, for the purpose of photolithography, surface cleaning, microstructuring, pattern microimaging, surface modification or the like, was presented.
Abstract: A high resolution, deep UV beam delivery system for exposing a surface, directly or through a mask, for the purpose of photolithography, surface cleaning, microstructuring, pattern microimaging, surface modification or the like, the delivery system including a deep UV radiation source for generating a beam of narrow wavelength deep ultraviolet radiation along a path, a first optical system in the path for homogenizing and shaping the deep UV energy in the path; and a second optical system in the path for directing radiation energy onto the surface of a substrate to be processed, the second optical system including large area mirror structure having a numerical aperture of at least 0.3 and a modular compensation assembly of refractive elements disposed between said large area mirror structure and said substrate and corresponding to the wavelength of the radiation source for compensating (reducing) image curvature introduced into the system by the large area mirror structure.
53 citations
Patent•
31 Mar 2000TL;DR: In this article, a flat field collimating lens system is used between the mirror scanning system and the mask arrays to correct the angular beam output of the repeat positioning mirror and redirects the beam so that it strikes a specific rear surface segment(s) of in the mask array.
Abstract: An imaging system for ablating an array matrix of high-density vias in a flexible and rigid desired object. The apparatus contains a mirror based x, y scanning repeat positioning and/or a single axis scanner positioning system that directs a single point of a coherent light radiation beam at desired individual mask segments. These mask segments are formed into a planar mask array. A flat field collimating lens system is positioned between the mirror scanning system and the mask arrays to correct the angular beam output of the repeat positioning mirror and redirects the beam so that it strikes a specific rear surface segment(s) of in the mask array. The flat field collimating lens provides a beam that either illuminates the mask perpendicular to its surface or at preselected optimized illumination angles. Once illuminated, the specific segment of the mask array images and processes a single or a plurality of desired holes or features in a top surface of a flexible or rigid desired object to be processed.
52 citations
Patent•
07 Mar 1983TL;DR: In this paper, a beam of broadband spatially-coherent light is converted to light with a controlled spatial incoherence and focused on the target, where an echelon-like grating breaks the beam up into a large number of differently delayed beamlets with delay increments larger than the coherence time of the beam, and a focusing lens overlaps the beamlets to produce at the target a complicated interference pattern modulated by a smooth envelope that characterizes the diffraction of an individual beamlet.
Abstract: A system for achieving very uniform illumination of a target. A beam of broadband spatially-coherent light is converted to light with a controlled spatial incoherence and focused on the target. An echelon-like grating breaks the beam up into a large number of differently delayed beamlets with delay increments larger than the coherence time of the beam, and a focusing lens overlaps the beamlets to produce at the target a complicated interference pattern modulated by a smooth envelope that characterizes the diffraction of an individual beamlet. On time scales long compared to the coherence time, the interference pattern averages out, leaving only the smooth diffraction envelope.
43 citations
TL;DR: In this article, a general formulation of multifaceted mirror configurations for transforming an arbitrary laser beam irradiance pattern into a uniform one was presented and compared with three configurations: a strip integrator, an imaging integrator and a multaceted integrator.
Abstract: This paper presents a general formulation of multifaceted mirror configurations for transforming an arbitrary laser beam irradiance pattern into a uniform irradiance pattern. Three configurations are presented and compared. Two of these configurations are new: a strip integrator that reduces manufacturing complexity and an imaging integrator that minimizes deleterious diffraction effects. Aberration effects associated with the relaying or imaging of the irradiance pattern and a novel technique for correction are also discussed.
33 citations