Abstract: A stepper lens train is mapped for curvature of field and distortion. A single plate, displaced from the reticle plane, is utilized for stepper correction. The plate is provided with a variable thickness mapped to correct curvature of field. The same plate is etched with stepped gratings typically on a flat surface of the plate.

Abstract: A reticle consisting of a multiplicity of small openings corresponding to separate and distinguishable points is put in the reticle plane. This reticle is imaged down through an opening O in aperture plate AP. A corresponding multiplicity of spots are created at the image plane of the optical system. These spots have spot centroids relative to the original separate and distinguishable points in the reticle. These points, however, are deviated from their diffraction limited positions by the average of grad .phi.(u)) over the corresponding ray bundle. The opening O in the aperture plate samples a discrete portion of the entrance pupil. With points spread out over an area of size 2*NAo*za, ray bundles with chief rays covering the entire entrance pupil will be projected down to image plane IP. The above outlined procedure is extended to analyzing the wavefront at a multiplicity of field points over the entire lens train. The process includes using an aperture plate AP consisting of a multiplicity of openings O.

Abstract: A mask for generating a high density regular matrix of working images for generating a corresponding high density regular matrix of vias in a substrate, the computer generated holographic images from overlapped subapertures are processed for maximum fluence. For each working image, a diverging wave front of the first order is propagated using Fresnel diffraction to produce for that wave front the corresponding first order holographic image at a central unit cell. The first order holographic image for each of the working images to be produced by the unit cell is added until the configuration of a unit mask cell containing portions of all working images to be broadcast is attained. The projection from the unit cell to working image is arbitrarily altered to attain the smallest local maximum first order transmission requirement within the central unit cell; the large local maximum first order transmission requirements are essentially moved outside the bounds of the central unit cell.

Abstract: A technique is described which provides for directly placing multiple patterns on a nonconducting substrate using an electron beam. Prior to patterning, a conductive coating is applied to the nonconductive substrate. The patterns are generated by controlling the position and the speed of movement of the electron beam. Each pattern contains fiducials lying outside of the pattern's active region. After a conductive layer has been exposed, the patterned regions are removed, typically through etching. A separate etch is used to etch the pattern into substrate. The unpatterned portions of the conductive coating are then removed and a new conductive coating is applied to the substrate, insuring that the fiducials are protected during the removal procedure so that they can be used to align subsequent patterns. This procedure is repeated as many times as necessary to form the desired number of patterns in the substrate.

Abstract: A beam scanning system and attached system of beam stabilization is utilized for ensuring the parallel transport of a scanned orthogonally deflected coherent light beam. A first scanning stage with right angle reflecting mirror scans the beam in the X-direction and reflects the scanned beam to the Y-direction. A second scanning stage with right angle reflecting mirror is mounted to the first scanning stage. This second scanning stage deflects the scanning beam in the Y-direction and reflects the beam downward. The scanning beam has divided out a small portion thereof as a reference beam. This reference beam is then diverted to precisely opposite orthogonal paths to the incidence of the scanning beam. The precise opposite orthogonal reference path results in upward deflection of the reference beam. After upward deflection, the reference beam is reflected at an optical flat and reflected back through the reference path. After retracing the orthogonal reference legs, the beam is diverted to a quad detector.

Abstract: A apparatus and process for ablating a matrix of high density vias in a flexible substrate. The apparatus is cantilevered on a horizontal shelf from a partition where it can be rigidly supported. A vacuum container reciprocates towards and away from the partition and supports the horizontal shelf by permitting supporting casters to bear on and be supported by the reciprocating container. When the container is away from the partition, servicing of the apparatus as well as the insertion an removal of substrate can occur. When the container is adjoined to the partition, a vacuum can be drawn on the apparatus and processing commenced. A continuous flexible substrate is provided extending in a circuitous path between a supply roll and a take up roll, all interior of the container. The flexible substrate is maintained under constant tension and incrementally advanced. The substrate is incrementally advanced and stopped, passing across a table.

Abstract: The apparatus for machining and material processing includes an excimer laser and a Fresnel zone plate array (FZP) positioned parallel to the workpiece, with the distance between the FZP and the workpiece being the focal length of the FZP. For each hole to be formed on the workpiece a corresponding Fresnel zone is patterned onto the FZP. Each Fresnel zone may be patterned directly centered over the desired hole location or in high density patterns it may be located off-center from the hole with deflection being accomplished by the formation of finer circular arcs on the side of the Fresnel zone opposite the desired direction of deflection. A beam scanner is included to provide a more uniform illumination of the FZP by the laser beam. The scanning eliminates non-uniformity of intensity. The alignment mechanism uses a helium-neon laser, the beam from the which is projected onto a surface relief grating on the workpiece.

Abstract: The process of the manufacture of both the conductive layers and dielectric layers of multichip modules of the deposited variety is set forth with direct etch techniques being substituted for photolithography. Simply stated, entire circuit layers of the modules are directly etched or patterned with the circuit configuration required. Three processes are disclosed for processing the individual layers including subtractive patterning of a metallic conductor layer and direct patterning of the dielectric layer; direct etch metal processing (DEMI) involving direct removal of the metal layer with subsequent direct patterning of the dielectric layer; and, plating form process involving additive metallization and direct etching of the dielectric layer. By utilizing the disclosed processes alone or in combination, fabrication of multichip modules can occur.

Abstract: A stepper configuration is modified by corrector plates so that an image from a reticle plane is projected to an ideal image at an object plane. The system correction is based on the premise that depth of field correction made at the reticle plane induces insignificant distortion correction. Further, distortion correction in turn induces insignificant changes in field correction. The preferred location of plates correcting for depth of field is therefore at the reticle plane, it being noted that distortion introduced by a field corrector plate at this location is negligible. Three generalized cases for correction are therefore discussed. The first case is field curvature correction where the correcting plate is registered to or close to the reticule plate; it is shown that induced distortion correction may be ignored. The second case is where field correction cannot be placed next to the reticle plate, but the field curvature induced by required distortion correction is negligible.

Abstract: Optical machining of a workpiece with coherent light scanning a plate with a plurality of subaperture subapertures is disclosed. Each of the subapertures creates a working image which when scanned with a coherent wave front of the design frequency forms in three dimensional space the working image. The working image when registered to a workpiece effect processing of the workpiece, usually ablating an aperture such as a blind via of small dimension. Improved techniques of dimensioning and fabricating the subaperture, creating amplitude modulation with the phase plate, and finally controlling amplitude with optical features close to the limit of producible optical elements is disclosed. The apparatus for the process, the process and the plate for utilization in the process are set forth.

Abstract: In a system of proximity printing utilizing coherent light, a technique of phase only image correction is disclosed. Specifically, a holographic corrector plate is utilized. The image on the holographic corrector plate is produced by constructing a holographic image from the broadcast image and the intended working image. The broadcast image and the intended working image are placed in precise proximity printing alignment. With the respective images aligned, a coherent light beam is split to provide two temporally and spatially coherent beams. One of the temporally and spatially coherent beams scans the broadcast image. The other temporally and spatially coherent beam scans a mask containing the intended working image in a corresponding scan. A plane of beam intersection is chosen, with precise correspondence between rays at any point on the broadcast mask to rays from corresponding points on the working image mask.

Abstract: In an apparatus and process for the direct ablation of substrates, an optical train is disclosed which enables large substrates to be processed from relatively small optical masks containing subaperture groups. Optical masks, preferably in the form of transparent plates containing computer generated holograms, are provided with at least discrete subaperture groups for sequential scanning and hence sequential processing of the substrate. A scanning beam in combination with a variable aperture overlying the mask sequentially scans the subaperture groups of the plates to produce direct laser ablation from a subaperture group intended to be scanned and prevents partial scanning of adjacent subaperture groups. Specialized plates with overlying generally negative lenses and subapertures elongated with respect to the radial direction of optical divergence are utilized to project images out from under the respective computer generated holograms to locations at the side of the plates without distortion.

Abstract: Transparent and wholly transmissive optical plates are disclosed in which features to be ablated are formed to produce varying levels of transmission of an ablating laser beam, preferably scanned across the plate. Use of the plate for ablation extends to forming openings of varying depths with timed ablating exposures of known intensity. Alternately, the ablation profile of a single image can be controlled utilizing a timed exposure of known intensity to provide an ablated opening of a specific designed profile in a workpiece. Three specific plate image constructions are illustrated. These include gratings which taper in width (continuous and step tapers both being disclosed), randomly placed diffracting elements which taper in density, and gratings having interrupted portions which taper in density. Where the intensity across a feature is uniform, ablation to controlled depths may occur.

Abstract: A method and apparatus is disclosed for laser ablation of openings with a specified wall profile in materials such as polyimide. The method includes identifying the opening profile of choice. This profile of choice is then divided into convex portions which can be "stably" formed and concave portions which are "unstably" formed. With respect to convex portions of apertures, after ablation to their desired depth, these convex portions remain substantially unchanged with additional exposure to otherwise ablating radiation. With respect to concave portions of apertures, these concave portions change with additional exposure to ablating radiation. Accordingly, techniques are disclosed for controlling exposure to ablating radiation, controlling the profile of the ablating radiation, or both. In either case, the intensity profile of the working image containing the ablating light is shaped in accordance with the depth and slope of the sidewalls of the opening desired.

Abstract: The laser ablation control system and method described is active in starting laser ablation, continuing laser ablation and finally tuning laser ablation in view of product output. First, it provides a means of generating initial settings for laser ablation tool operation utilizing the high predictability of ablation on substrates of known composition. Second, it provides real time monitoring and control of the laser output in terms of the characteristics important to the system performance as it relates to the abalation process. Third, it entails statistical analysis of the photo ablated pattern with correspondent adjustment to abalation parameters. Most importantly, these elements are continuously combined to achieve optimized performance monitored during the ablation process.

Abstract: The process of the manufacture of both the conductive layers and dielectric layers of multichip modules of the deposited variety is set forth with direct etch techniques being substituted for photolithography. Simply stated, entire circuit layers of the modules are directly etched or patterned with the circuit configuration required. Three processes are disclosed for processing the individual layers including subtractive patterning of a metallic conductor layer and direct patterning of the dielectric layer; direct etch metal processing (DEMI) involving direct removal of the metal layer with subsequent direct patterning of the dielectric layer; and, plating form process involving additive metallization and direct etching of the dielectric layer. By utilizing the disclosed processes alone or in combination, fabrication of multichip modules can occur.

Abstract: A method and apparatus for the production of transparent phase reticule mask for projecting high intensity light--such as that used for direct laser ablation of materials from substrates--is disclosed. The transparent phase reticule mask includes first portions which are for scattering light beyond the solid angle of an imaging system and second transparent portions which scatter light to an angle where projection by an imaging system can occur. Phase reticule mask configurations are disclosed including a known phase reticule mask which has gratings, and a new phase reticule mask having random phase roughening for the scattering of light. Random phase roughening includes imparting to the roughened area a mean solid angle of scattering that exceeds the solid angle of collection of an image system. Thus, the total fraction of incident light is below the ablation threshold and constitutes the dark patterned region of the mask.

Abstract: The phase mask comprises binary square wave gratings which deflect light away from the collecting aperture of the projection system and binary phase gratings which deflect the incident light into a fan of rays to fill the collecting aperture. In the transmissive regions, the mask consists of randomly-placed squares etched to a depth corresponding to a half wave retardation and filling approximately fifty percent of the area within the transmissive region. The "blocking" regions consist of a binary grating etched to the same depth as that of the transmissive region but having sufficiently high spatial frequency to deflect the incident light to points outside of the collecting aperture.

Abstract: An apparatus for using and a process of using a Fresnel zone plate array is utilized for processing materials. An optically stable frame receives coherent light and passes the coherent light through beam processing optics such as a collimator, a beam expanding telescope and an aperture. Thereafter, the beam is routed to scanning mirrors immediately overlying a Fresnel zone plate array. The Fresnel zone plate array has a plurality of discrete subapertures with each subaperture containing image information at a discrete working distance from the plate; each image produced by a subaperture of the Fresnel zone plate array typically differs from adjacent images from adjacent subapertures typically in size, shape or gain. The beam is scanned and registered to a discrete selected subaperture on the plate to cause an image from the subaperture to form on a work piece located at the working distance of a scanned subaperture.

Abstract: An object is projected through the lens system to be corrected to the image plane where the position of the diffraction limited ideal image is readily ascertainable. At least one primary image defect or Seidel Aberration is measured. These aberrations include distortion, curvature of field or Petzval curvature, spherical aberration, coma, and astigmatism. Interferometry is one technique typically used to measure the aberrations of the system. Based on the measurements, the location of an apparent object is computed. The apparent object is an imaginary location of the object which would cause the image of the object to register to the diffraction limited ideal image. Although only one corrector plate may be required to achieve the desired optical system performance improvements, in the preferred embodiment at least two corrector plate mounting planes are designed and mounts made for the insertion of first and second corrector plates to correct beam convergence and focus to the ideal image.