California Jamar, Incorporated

Jamar Technologies Co.

Imar Technology Company

Jmar Research, Inc.

Jmar Technology Co.

Tamar Technology Co.

Henry Shields

Harry Rieger

Richard M Foster

Arthur L Morsell

Michael Powers

A laser system which generates short duration pulses, such as under five nanoseconds at an energy level of up to a few milli-Joules per pulse (mJ/p) with near diffraction limited beam quality. A laser crystal is pumped (excited) by diode lasers. A resonator having at least two mirror surfaces defines a beam path passing through the laser crystal. The beam path in the resonator is periodically blocked by a first optical shutter permitting pump energy to build up in the laser crystal, except for a short period near the end of each pumping period. While the first optical shutter is open a second optical shutter blocks the light in the resonator except for periodic short intervals, the intervals being spaced such that at least one light pulse traveling at the speed of light in the resonator is able to make a plurality of transits through the resonator, increasing in intensity by extracting energy from the excited laser crystal on each transit. After the light pulse has built up in intensity, an optical release mechanism releases the pulse from resonator.

Short pulse laser system

A solid state laser systems for generating highly monochromatic laser radiation at wavelengths of interest for advanced micro-lithography, particularly 248 nanometer and 193 nanometer wavelengths. At least one Nd:YAG laser produces a 1,064 nm laser beam consisting of narrow-linewidth pulses of infra-red laser radiation having a pulse duration of less than 30 nanoseconds, at a pulse rate preferably in excess of 500 pulses per second with pulse energy greater than 20 millijoules. This radiation is frequency doubled and frequency tripled to produce 532 nm and 355 nm pulsed laser beams. These beams are then further optically processed to generate the ultra-violet wavelength for micro-lithography at either 248 nm or 193 nm.

Solid-state laser system for ultra-violet micro-lithography

A high average power, high brightness solid state laser system. We first produce a seed laser beam with a short pulse duration. A laser amplifier amplifies the seed beam to produce an amplified pulse laser beam which is tightly focused to produce pulses with brightness levels in excess of 10.sup.11 Watts/cm.sup.2. Preferred embodiments produce an amplified pulse laser beam having an average power in the range of 1 kW, an average pulse frequency of 12,000 pulses per second with pulses having brightness levels in excess of 10.sup.14 Watts/cm.sup.2 at a 20 .mu.m diameter spot which may be steered rapidly to simulate a larger spot size. Alternately, a kHz system with several (for example, seven) beams (from amplifiers arranged in parallel) can each be focused to 20 .mu.m and clustered to create effective spot sizes of 100 to 200 .mu.m. These beams are useful in producing X-ray sources for lithography.

Low cost, high average power, high brightness solid state laser

A laser system which generates pulses with a duration in the range of about 60 to 300 ps at an energy level of up to a few milli-Joules per pulse (mJ/p) with near diffraction limited beam quality. A laser crystal is pumped (excited) by diode lasers. A resonator having at least two mirror surfaces defines a beam path passing through the laser crystal. The beam path in the resonator is periodically blocked by a first optical shutter permitting pump energy to build up in the laser crystal, except for a short period near the end of each pumping period. While the first optical shutter is open a second optical shutter blocks the light in the resonator except for periodic subnano-second intervals, the intervals being spaced such that at least one light pulse traveling at the speed of light in the resonator is able to make a plurality of transits through the resonator, increasing in intensity by extracting energy from the excited laser crystal on each transit. After the light pulse has built up in intensity, an optical release mechanism releases the pulse from resonator.

Picosecond laser

An improved high average power, high brightness laser system. The laser system comprises an XeCI excimer amplifier, an XeCI excimer preamplifier, a means for generating a picosecond seed pulse tailored for the XeCI preamplifier and the XeCI amplifier and a means for focusing the output pulse laser beam onto a spot smaller in area than 100.times.10.sup.-6 cm.sup.2. We first produce a seed laser beam consisting of a series of bunches of short duration pulses with a bunch frequency in excess of 100 pulses per second. These seed laser pulses are produced by a Nd:YAG pumped dye laser oscillator with a cavity dumper. The pulses in the beam are preamplified in a multipass preamplifier and the pulses are then multiplexed in a pulse train generator into a larger number of lower power pulses. A multi-pass laser amplifier then amplifies each pulse in the bunched pulse laser beam to produce an amplified pulse laser beam which is then tightly focused to so that the individual pulses are at brightness levels in excess of 10.sup.11 Watts/cm.sup.2. A prototype device built and tested by Applicants and their fellow workers has produced a pulsed laser beam with 50 ps, 30.times.10.sup.-3 Joule pulses at 1,120 pulses per second to provide a beam with average power of 34 Watts. Focusing the beam at a 10 micron diameter spot produces intensity levels of 7.times.10.sup.14 per cm.sup.2. Using an iron target Applicants have produced X-ray sources of average X-ray power levels in excess of 3.5 Watts. This source is capable of printing integrated circuits with dimensions in the range of 0.1 micron to 0.25 micron at rates of about 10 wafers per hour.

Laser generated X-ray source

A high average power, high brightness solid state laser system. We first produce seed laser beam with a short pulse duration and frequency in excess of 1,000 pulses per second. A laser amplifier amplifies the seed pulse beam to produce an amplified pulse laser beam which is focused to produce pulses with brightness levels in excess of 10.sup.11 Watts/cm.sup.2. Preferred embodiments produce an amplified pulse laser beam having an average power in the range of 1 kW, an average pulse frequency of 12,000 pulses per second with pulses having brightness levels in excess of 10.sup.14 Watts/cm.sup.2 at a 20 .mu.m diameter spot which is steered rapidly to simulate a larger spot size. These beams are useful in producing X-ray sources for lithography. In one preferred embodiment, the seed beam is produced in a mode locked Nd:YAG oscillator pumped by a diode array with the frequency of the pulses being reduced by an electro-optic modulator. In a second preferred embodiment, the seed beam is Q switched and includes a Pockels cell for cavity dumping. In a third preferred embodiment, the short duration high frequency pulses for the seed beam is produced by a very short Nd:YAG crystal and a .lambda./2 Pockels cell. As compared with prior art high brightness lasers, we have achieved our very high brightness by reducing the pulse duration by about 2 or 3 orders of magnitude, from a few ns to 100 ps or less and by focusing on a very small spot, but we are able to simulate a much larger spot by very rapidly steering our high average power beam over the area we need.

A high average power, high brightness solid state laser system. A laser produces a first pulse laser beam with a high pulse frequency. A pulse spacing selector removes from the first pulse laser beam more than 80 percent of the pulses to produce a second pulse laser beam having a series of periodically spaced short pulses in excess of 1,000 pulses per second. A laser amplifier amplifies the second pulse train to produce an amplified pulse laser beam which is focused to produce pulses with brightness levels in excess of 10.sup.11 Watts/cm.sup.2. A preferred embodiment produces an amplified pulse laser beam having an average power in the range of 1 KW, an average pulse frequency of 12,000 pulses per second with pulses having brightness levels in excess of 10.sup.14 Watts/cm.sup.2 at a 20 .mu.m diameter spot which is steered rapidly to simulate a larger spot size. These beams are useful in producing X-ray sources for lithography. As compared with prior art high brightness lasers, we have reduced the pulse duration by about 2 or 3 orders of magnitude, from a few ns to 100 ps or less. We achieve our very high brightness by focusing on a very small spot, but we are able to simulate a much larger spot by very rapidly steering our high average power beam over the area we need.

A laser plasma X-ray source for use in photolithography is disclosed wherein an electro-optical shutter is used to trim the output pulse from a master oscillator to a desired duration. The pulse is then split into several pieces which travel along various optical delay paths so that the pieces pass sequentially through a laser power amplifier. After amplification, the pieces are reassembled and then focussed at the plasma target. In a first embodiment, polarization and angle coding methods are used to distinguish each pulse piece at it travels along the delay paths. In a second embodiment, polarization coding is replaced by additional angle coding transverse to the plane of the angles of the first embodiment. An expander/reducer lens assembly is used in both embodiments to reduce the angles between the beam paths and allow more beams to fit closely to the laser amplifier gain region.

Laser plasma X-ray source

A laser plasma X-ray source for use in photolithography is disclosed wherein an electro-optical shutter is used to trim the output pulse from a master oscillator to a desired duration. The pulse is then split into several pieces which travel along various optical delay paths so that the pieces pass sequentially through a laser power amplifier. After amplification, the pieces are reassembled and then focussed at the plasma target. In a first embodiment, polarization and angle coding methods are used to distinguish each pulse piece as it travels along the delay paths. In a second embodiment, polarization coding is replaced by additional angle coding transverse to the plane of the angles of the first embodiment. An expander/reducer lens assembly is used in both embodiments to reduce the angles between the beam paths and allow more beams to fit closely to the laser amplifier gain region.

Growing community of inventors

San Diego, CA, United States of America

Henry Shields