Showing papers on "Polishing published in 1979"

Method of polishing a semiconductor wafer

Abstract: A semiconductor wafer (31) is placed on a non-porous, flat, substrate (10), with a thin layer of water (21) interposed therebetween. The substrate (10) with the wafer (31) thereon is placed in a polishing machine (40) where a rotating polishing pad (43) polishes the wafer which is permitted to float free and rotate on the thin layer of water (21) during the polishing operation.

Process for evening out the amount of material removed from discs in polishing

Abstract: In conventional polishing machines, uneven transmission of pressure causesifferent degrees of abrasion of the polished discs which results in different thicknesses over one disc and also with respect to other discs in one polishing batch. This problem is solved according to the invention by the provision of soft elastic inserts between the pressure piston and the back of the carrier plate on which the discs to be polished are cemented.

Semiconductor substrate and a manufacturing method thereof

Abstract: This invention relates to a semiconductor substrate and a method of manufacturing the same. In a semiconductor manufacturing process for a Si single crystal wafer or the like, before the step of mirror polishing, the rear surface of a Si wafer is ground to form a damaged layer having a certain fixed thickness, the Si wafer is subsequently etched by chemical etching if desired, and the rear surface is further formed with an oxide film by thermal oxidation if desired, whereby a semiconductor substrate exhibiting an intense gettering effect is manufactured.

Etching Studies on Singly and Doubly Rotated Quartz Plates

Abstract: : Experiments aimed at finding a chemical polish for the doubly rotated SC-cut have been performed with a variety of etchants. The surface morphologies of etched SC-cut plates depend strongly on the composition of the etching solutions. Some of the solutions evaluated did not produce chemical polishing on either side of the SC-cut plates, some produced chemical polishing on one side but not the other, and some were able to polish both sides. It has also been shown that at least up to 10 MHz, the chemical polishing does not produce a significant 0 degradation for AT-cut quartz crystal resonators.

Grinding or polishing tool

Abstract: A tool is disclosed for precisely grinding or polishing the surface of a workpiece, such as the mating end face of a fiber optic ferrule. The tool utilizes a planar grinding wheel which is caused to rotate and simultaneously shift transversely in the plane in which it lies by the use of an eccentric driving connection to the wheel and gear teeth on the outer surface of the wheel and gear teeth on the interior of the chamber in which the wheel is mounted. Such movement of the wheel causes the workpiece to be ground in multiple directions across its face.

Improvements in coated abrasives

Abstract: Coated abrasives comprising a sheet (1) of paper or fabric coated with abrasive particles in an adhesive binder are made more flexible and longer-lasting by applying the abrasive particles in the binder in an array of discrete dots (3) covering only part of the area of the sheet. The performance of the product is further improved by the use of a backing sheet (2) of flexible synthetic foam material. The products are sanding sheets which may be made into belts or discs for use on machines and tools, cleaning and polishing sheets, and dishwashing pads.

Process for the chemical etch polishing of semiconductors

Abstract: A method for thinning and polishing semiconductor materials such as gallium arsenide is disclosed. This method utilizes a chemical etchant in conjunction with a grooved flat polishing plate. The polishing plate has a hardness greater than 2 on the mohs scale. High quality polished surfaces are obtained. Exemplary of polishing plate materials is quartz.

The emissivity of LaB6 at 650 nm

Abstract: The emissivity of LaB6 at 650 nm between 1600 and 2100 K can be described by the equation e=1.2144−2.467×10−4Ts, where Ts is the observed surface temperature.

Precision polishing suspension and method for making same

Abstract: A permanent precision liquid polishing suspension, and a method for making same, comprising fine abrasive polishing powders held in a suspension medium comprising an aqueous glycerine based composition thickened by a carboxy polymethylene polymer.

Grinding And Polishing With Small Tools Under Computer Control

Abstract: Small grinding and polishing tools are useful for certain applications since they can closely follow the curve of an aspheric surface and are less affected by workpiece distortion than larger tools. Also, the use of a computer to control the action of grinding and polishing tools can increase the efficiency and accuracy of the process. The computer controlled polisher (CCP) takes adantage of both features, moving a tool assembly with small pads over the workpiece under computer control. By varying the amount of time the machine works any region, a controlled amount of material may be removed. The best tool configuration for any figuring operation is determined by use of co puter modeling, while the proper operating parameters are obtained from ex perimentation. The process has been used to fabricate a nu her of difficult mirrors; as a result of this work, the CCP will be used on important future fabrication efforts.

Off-axis mirrors made using a conventional milling machine

Abstract: The method described here will generate many commonly needed off-axis surfaces of revolution (ellipsoids, paraboloids, hyperboloids, and more complicated shapes) to an accuracy sufficient for use as mirrors in the far ir (λ > 20 μm) using only a conventional milling machine equipped with a rotary table. The technique is an approximation which seems applicable to reasonable accuracy as long as the focal ratio ƒ is not too small and the surface is not too close to on axis. Only small sections of such surfaces can be produced. Careful cutting and polishing will yield a surface quality good enough to allow alignment with visible light. The geometry of the milling machine setup is shown in Fig. 1 and is similar to that of the machinist's method for pro­ ducing spherical surfaces. The rotary table is clamped to the mill bed with its axis vertical. This axis is defined as the z axis. A fly cutter of radius R is chucked into the mill. The head of the mill is tipped by an angle (90° -θ) from its usual vertical axis. Lines extending along the axes of the rotary table and the mill cutter have a closest approach distance of D. The remaining independent variable S is the distance between the plane of the cutter and the rotary table axis, measured in the z = 0 plane (which is the horizontal plane passing through the center of the circle swept out by the cut­ ter). A surface of revolution is generated by clamping a piece of stock to the rotary table, running the fly cutter at high rpm (as high as is safe), and turning the table slowly to feed the work. The surface cut into the work is a complicated shape described by the equation

Diamond-Machined Geodesic Lenses In LiNbO3

Abstract: The application of single point diamond turning to the fabrication of aberration-corrected, aspheric geodesic lenses in LiNb03 for use in integrated optics is reported F/5 lenses with useful apertures of 4 mm and 5 mm have been produced Lens profile accuracies ranging between 15 and 3 pm total indicator reading and depth accuracies of 025 to 20 μm have been achieved The machined surfaces require only light polishing, which produces little effect on the figure accuracy, to remove residual machining marks Waveguides grown by Ti-indiffusion are found to be characterized by very low scattering losses Optical image spot sizes of 135 to 223 times diffraction-limited have been measured for input beam widths of 10 to 328 mm for a lens in which the edge rounding has not been incorporated into the aspheric correction The edge rounding has been included in the correction for subsequent lenses© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only

Automatic polishing apparatus

Abstract: An automatic polishing apparatus having in combination, a polishing machine for effecting the polishing and a profiling device for giving an instruction concerning the path along which the polishing is to be effected to the polishing machine. The profiling device has a tracer adapted to trace and profile a line which has been previously drawn in a drawing in accordance with the configuration of the surface to be ground, and detecting device adapted to detect the displacements of the tracer in the directions of X and Y-axes. The polishing machine includes a feeding arrangement adapted to feed one of a table carrying the article to be ground and a polishing head carrying the polishing tool relatively to the other in the directions of X and Y-axes, in accordance with signals representing the displacements in both directions of the tracer derived from the detecting device of the profiling device. The feed is made at a predetermined proportional ratio to the displacements of the tracer. A detector is carried by the polishing head and is adapted to detect the pressure applied to the polishing tool or a displacement caused by the pressure. A polishing arrangement is adapted to move one of the table and polishing head relatively to the other in the direction of Z-axis in accordance with the output from the detector so as to maintain the polishing tool in contact with the ground surface at a predetermined level of contact pressure to thereby effect a self-guided profiling polishing of the surface. The combination of the profiling device and the polishing machine permits an automatic polishing in accordance with the shape of the free curved surface to be polished.

Titanium in-diffused LiNbO(3) optical waveguide fabrication.

Abstract: Techniques used to fabricate titanium in-diffused optical waveguide devices in LiNbO3 are described. The processes described include photolithography, precision mask orientation and registration, metal diffusion, waveguide end polishing, and crystal cleaving.

Manufacture of semiconductor device

Abstract: PURPOSE:To improve electric characteristics with strain in an element region eliminated, by heat-treating the reverse surface of a semiconductor substrate, with a semiconductor element on its top surface, at a temperature of more than 200 deg.C after mechanically polishing the reverse surface to a fixed thickness. CONSTITUTION:On semiconductor substrate 1, epitaxial layer is grown, the surface is covered with oxidized film 3, and after base region 4 and emitter region 5 are both provided, metal electrode 6 is fitted. The reverse surface of substrate 1 of the semiconductor device formed in this way is mechanically polished to a thickness suitable for pelletizing, thereby generating strain between substrate 1 and epitaxial layer 2. In other words, plastic strain layer 11 close to polished surface 7, plastic- elastic strain layer 12 from its top closely to the surface of substrate 1, and elastic strain layer 13 from its top to the surface of epitaxial layer 2 are formed respectively. Next, a heat treatment of 400-500 deg.C is done in N2 gas for sixty minutes to remove strain completely except elastic strain layer 12 near polished surface 7. Consequently, the manufacture yield improves.

Grinding And Polishing With Small Tools Under Computer Control

Abstract: Small grinding and polishing tools are useful for certain applications since they can closely follow the curve of an aspheric surface and are less affected by workpiece distortion than larger tools. Also, the use of a computer to control the action of grinding and polishing tools can increase the efficiency and accuracy of the process. The computer controlled polisher (CCP) takes advantage of both features, moving a tool assembly with small pads over the workpiece under computer control. By varying the amount of time the machine works any region, a controlled amount of material may be removed. Using computer modeling, the best tool configurations are developed to perform any figuring operation. Based upon experimentation, the proper operating parameters for the CCP have been obtained. The machine has been used to fabricate a number of difficult mirrors. As a result of this work, the CCP will be used on important fabrication efforts.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Method for polishing a single crystal or gadolinium gallium garnet

Abstract: A mechanochemical method of polishing a gadolinium gallium garnet single crystal characterized by the use of a composition made of a polishing agent selected from the group consisting of aluminum oxide, cerium oxide, zirconium oxide and chromium oxide suspended in an alkaline silicate solution selected from a group consisting of sodium silicate solution and potassium silicate solution.

Polishing implement for varnished surfaces - has vibration drive in housing in form of handle and is connected to insert with disc

Abstract: The implement is for surface treatment esp. for polishing varnished or painted surfaces. There is a housing (10) of a vibration drive (26, 28) in the form of a handle. While an insert (12) is connected with the housing and carries an operating disc (14). This insert (12) is connected with the housing so that it can be replaced. Specifically, there is a plug connection (48, 54) between the housing and support insert. The implement can be a rod-shaped housing (10) with a lidded battery chamber (34) on the side of the vibration drive away from the insert.

Grinding or polishing tool for cylindrical grinding machines - is built up from discs mounted on common support and opt. spaced by washers

Abstract: The grinding or polishing tool is built up from a number of coaxially mounted discs (1). The grinding discs each consist of a flexible carrier in or on which abrasive material is embedded or mounted. The discs are mounted on a shaft or bolt (9) between two flanges (10). The diameters of the discs can be varied to give the grinding tool a particular contour. For increased flexibility, washers can be mounted between the discs.

Fabrication of small nonsymmetrical aspheric surfaces.

Abstract: Equipment and procedures have been developed for the fabrication of small nonsymmetrical aspheric surfaces. A grinding or polishing pad is used which is much smaller than the workpiece. The oscillating motion of the workpiece under the pad coupled with the grinding or polishing slurry produces material removal. Control over this removal is accomplished by varying the speed of the pad as it travels over different regions of the workpiece. The technique has been used to fabricate two nonsymmetrical aspheric metal mirrors.

Aspherical surface polishing with a ring polisher

Abstract: The ring-shaped polisher analyzed by Vinokur is modified to be a high-speed polisher for aspherical surfaces. The mathematical modeling of the ring polisher has been reformulated to examine the uniformity of surface polishing over the workpiece. The fabrication of a ring polisher is described, and experimental results of direct polishing of ground aspherical surfaces are discussed.

Composite gold and platinum jewellery - is made by heating gold on platinum as support until it melts and fuses

Abstract: The jewellery such as a ring is made by applying the gold in the solid state onto the platinum which is the support metal and then heating the gold up to its melting temp The finished ring then has the full lustre of gold without the need for any subsequent finishing such as polishing The melted gold bonds tightly with the platinum The end product can then be worked as required by mechanical tools Other items such as bracelets, chains, brooches etc can be made in a similar way

Press mould copying polishing machine - has copying unit with control system for travel and pressure at polishing head

Abstract: The copy polishing machine for press mouldes has a copying unit and a separate unit for the control system alongside, and spaced from them, a remote control panel. The machine itself has the polishing head mounted at the bottom of a vertical drive spindle which can be raised and lowered above the table carrying the workpiece. The copying unit has a sensor which can be moved sideways (X direction) also backwards and forwards (Y direction) above a template below. The polishing head is mounted on a motor drive spindle, the motor being mounted in a frame with a securing member at the top for controlling the pressure applied. The polishing head or the work table can be moved in the X and Y directions and pressure controlled in response to signals from the electronic control system.

Device for use in polishing table facets of gems

Abstract: A polishing device is described particularly useful for polishing table facets of gems, the device comprising a rotary polishing disc and a plurality of spring fingers mounted in cantilever fashion to overlie the polishing disc, with each spring finger including a pad formed with a socket adapted to receive a gem to be polished by the disc. A pressure bar urged by an electromagnet overlies the upper faces of all the spring fingers to apply a preselected, substantially uniform pressure to them during the polishing operation.