Abstract: In general, in one aspect, a method includes determining a critical dimension (CD) distribution on a photomask by measuring deep Ultra-Violet (DUV) transmission across the photomask.

Abstract: A contribution to a wafer level critical dimension distribution from a scanner of a lithography system can be determined based on measured wafer level critical dimension uniformity distribution and a contribution to the wafer level critical dimension distribution from a photo mask. Light transmission (104) across the photo mask (162) can be measured, a transmittance variation distribution of the photo mask can be determined, and the contribution to the wafer level critical dimension distribution from the photo mask (162) can be determined (132) based on the transmittance variation distribution of the photo mask.

Abstract: Bulk GaN and AlGaN single crystal boules, preferably fabricated using a modified HVPE process, are provided. The single crystal boules typically have a volume in excess of 4 cubic centimeters with a minimum dimension of approximately 1 centimeter. If desired, the bulk material can be doped during growth, for example to achieve n-, i-, or p-type conductivity.

Abstract: A method includes generating, using a data processor, information showing variations of a parameter across a photo mask relative to an average value of the parameter measured at various locations on the photo mask. For example, the information can include data points, and each data point can be determined based on a ratio between a measurement value and an average of a plurality of measurement values.

Abstract: Optimization of decoupling design selection for electronic designs is described. Initially an electronic design, such as, a printed circuit board, having a power delivery network with a given impedance value is identified. A target impedance value for the power delivery network is also identified. Subsequently, a decoupling impedance value, that, if added to the impedance of the power delivery network would transform the given impedance value into the target impedance value, is derived. In many implementations, the power delivery network may have a number of ports. Accordingly, a decoupling impedance value may be derived for each port. A selection of decoupling devices, each having a given impedance value, are also identified. Subsequently, a system of equations is formed that relates the decoupling devices and their associated impedance values to the decoupling impedance values.

Abstract: The invention relates to a method for determining at least one unknown laser beam parameter of a laser beam used for correcting errors of a transparent material including inducing a first persistent modification in the material by an interaction with the laser beam having a first set of laser beam parameters, measuring the induced first persistent modification of the material, calculating a second persistent modification in the material using a model describing persistent modifications in the material with a second set of laser beam parameters, wherein the first set of laser beam parameters comprises the second set of laser beam parameters and the at least one unknown laser beam parameter, setting up a target functional including the first persistent modification and the second persistent modification, and determining the at least one unknown laser beam parameter by minimizing the target functional.

Abstract: Method for producing a III-N (AlN, GaN, AlxGa(1-x)N) crystal by Vapor Phase Epitaxy (VPE), the method comprising: providing a reactor having: a growth zone for growing a III-N crystal; a substrate holder located in the growth zone that supports at least one substrate on which to grow the III-N crystal; a gas supply system that delivers growth material for growing the III-N crystal to the growth zone from an outlet of the gas supply system; and a heating element that controls temperature in the reactor; determining three growth sub-zones in the growth zone for which a crystal grown in the growth sub-zones has respectively a concave, flat or convex curvature; growing the III-N crystal on a substrate in a growth region for which the crystal has a by desired curvature.

Abstract: A method for inducing a controllable jet in a transparent liquid is disclosed. The method comprises providing a gas-liquid interface, providing a laser source and generating a beam comprising a sequence of laser pulses, and focusing the beam to a target location within the liquid at a predetermined distance from the gas-liquid interface and creating a plurality of cavitation bubbles, yielding a jet directed away from the gas-liquid interface. Other methods and apparatus are also described and claimed.

Abstract: A method for correcting a plurality of errors of a photolithographic mask, comprising optimizing first parameters of a imaging transformation of the photolithographic mask and second parameters of a laser beam locally directed onto the photolithographic mask, and correcting the plurality of errors by applying an imaging transformation using optimized first parameters and locally directing the laser beam onto the photolithographic mask using optimized second parameters, wherein the first and the second parameters are simultaneously optimized in a joint optimization process.

Abstract: Method for producing a III-N (AlN, GaN, AlxGa(1-x)N) crystal by Vapor Phase Epitaxy (VPE), the method comprising: providing a reactor having: a growth zone for growing a III-N crystal; a substrate holder located in the growth zone that supports at least one substrate on which to grow the III-N crystal; a gas supply system that delivers growth material for growing the III-N crystal to the growth zone from an outlet of the gas supply system; and a heating element that controls temperature in the reactor; determining three growth sub-zones in the growth zone for which a crystal grown in the growth sub-zones has respectively a concave, flat or convex curvature; growing the III-N crystal on a substrate in a growth region for which the crystal has a by desired curvature.

Abstract: Bulk GaN and AlGaN single crystal boules, preferably fabricated using a modified HVPE process, are provided. The single crystal boules typically have a volume in excess of 4 cubic centimeters with a minimum dimension of approximately 1 centimeter. If desired, the bulk material can be doped during growth, for example to achieve n-, i-, or p-type conductivity.

Abstract: In general, in one aspect, a method includes determining a critical dimension (CD) distribution on a photomask by measuring deep Ultra-Violet (DUV) transmission across the photomask.

Abstract: Method for producing a III-N (AlN, GaN, AlxGa(1-x)N) crystal by Vapor Phase Epitaxy (VPE), the method comprising: providing a reactor having: a growth zone for growing a III-N crystal; a substrate holder located in the growth zone that supports at least one substrate on which to grow the III-N crystal; a gas supply system that delivers growth material for growing the III-N crystal to the growth zone from an outlet of the gas supply system; and a heating element that controls temperature in the reactor; determining three growth sub-zones in the growth zone for which a crystal grown in the growth sub-zones has respectively a concave, flat or convex curvature; growing the III-N crystal on a substrate in a growth region for which the crystal has a by desired curvature.

Abstract: A method for producing, trapping and manipulating a gas microbubble in liquid is disclosed. The method includes providing a pulsed laser source for generating a pulsed laser radiation and focusing optics; and focusing a pulsed laser radiation to a focal zone within the liquid, with energy exceeding the threshold of optical breakdown in the liquid at the focal zone. It is also suggested to use focusing optics to focus the laser beam to a focal point at a depth close to the compensation depth of the focusing optics for spherical aberration.

Abstract: A method for compensating for critical dimension (CD) variations of pattern lines of a wafer, by the correcting the CD of the corresponding photomask. The photomask comprises a transparent substrate having two substantially opposite surfaces, a first back surface and a second front surface on which front surface an absorbing coating is provided, on which the pattern lines were formed by removing the coating at the pattern lines. The method comprises: determining CD variations across regions of a wafer exposure field relating to the photomask; and providing Shading Elements (SE) within the substrate of the photomask in regions which correlates to regions of the wafer exposure field where CD variations greater than a predetermined target value were determined, whereby the shading elements attenuate light passing through the regions, so as to compensate for the CD variations on the wafer and hence provide and improved CD tolerance wafer.

Abstract: Hydride phase vapor epitaxy (HVPE) growth apparatus, methods and materials and structures grown thereby. A HVPE growth apparatus includes generation, accumulation and growth zones. A first reactive gas reacts with an indium source inside the generation zone to produce a first gas product having an indium-containing compound. The first gas product is transported to the accumulation zone where it cools and condenses into a source material having an indium-containing compound. The source material is collected in the accumulation zone and evaporated. Vapor or gas resulting from evaporation of the source material forms reacts with a second reactive gas in the growth zone for growth of ternary and quaternary materials including indium gallium nitride, indium aluminum nitride, and indium gallium aluminum nitride.

Abstract: A method and apparatus for fabricating thin Group III nitride layers as well as Group III nitride layers that exhibit sharp layer-to-layer interfaces are provided. According to one aspect, an HVPE reactor includes one or more gas inlet tubes adjacent to the growth zone, thus allowing fine control of the delivery of reactive gases to the substrate surface. According to another aspect, an HVPE reactor includes both a growth zone and a growth interruption zone. According to another aspect, an HVPE reactor includes a slow growth rate gallium source, thus allowing thin layers to be grown. Using the slow growth rate gallium source in conjunction with a conventional gallium source allows a device structure to be fabricated during a single furnace run that includes both thick layers (i.e., utilizing the conventional gallium source) and thin layers (i.e., utilizing the slow growth rate gallium source).

Abstract: HVPE method for simultaneously fabricating multiple Group III nitride semiconductor structures during a single reactor run. A HVPE reactor includes a reactor tube, a growth zone, a heating element and a plurality of gas blocks. A substrate holder is capable of holding multiple substrates and can be a single or multi-level substrate holder. The gas delivery blocks are independently controllable. Gas flows from the delivery blocks are mixed to provide a substantially uniform gas environment within the growth zone. The substrate holder can be controlled, e.g., rotated and/or tilted, for uniform material growth. Multiple Group III nitride semiconductor structures can be grown on each substrate during a single fabrication run of the HVPE reactor. Growth on different substrates is substantially uniform and can be performed on larger area substrates, such as 3-12? substrates.

Abstract: A method and apparatus for growing low defect, optically transparent, colorless, crack-free, substantially flat, single crystal Group III nitride epitaxial layers with a thickness of at least 10 microns is provided. These layers can be grown on large area substrates comprised of Si, SiC, sapphire, GaN, AlN, GaAs, AlGaN and others. In one aspect, the crack-free Group III nitride layers are grown using a modified HVPE technique. If desired, the shape and the stress of Group III nitride layers can be controlled, thus allowing concave, convex and flat layers to be controllably grown. After the growth of the Group III nitride layer is complete, the substrate can be removed and the freestanding Group III nitride layer used as a seed for the growth of a boule of Group III nitride material. The boule can be sliced into individual wafers for use in the fabrication of a variety of semiconductor structures (e.g., HEMTs, LEDs, etc.).

Abstract: An apparatus for growing bulk GaN and AlGaN single crystal boules, preferably using a modified HVPE process, is provided. The single crystal boules typically have a volume in excess of 4 cubic centimeters with a minimum dimension of approximately 1 centimeter. If desired, the bulk material can be doped during growth to achieve n-, i-, or p-type conductivity. In order to have growth cycles of sufficient duration, preferably an extended Ga source is used in which a portion of the Ga source is maintained at a relatively high temperature while most of the Ga source is maintained at a temperature close to, and just above, the melting temperature of Ga. To grow large boules of AlGaN, preferably multiple Al sources are used, the Al sources being sequentially activated to avoid Al source depletion and excessive degradation.