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Keltech Engineering, Inc.

Cameron M Duescher

Wayne O Duescher

Kent Wayne Duescher

Embodiments of a high-speed rotatable workpiece abrasive polishing head are disclosed that allow flat surfaced hard material workpieces or sapphire or semiconductor wafers to be polished at high abrading speeds that can use water-mist cooled quick-change fixed abrasive island-type discs. Workpieces can be quickly attached with vacuum to a rotatable workpiece plate having a curved (e.g., spherical) bearing with an offset spherical center of rotation located at the workpiece abraded surface. Abrading contact there prevents lateral abrading friction forces from tilting workpieces and causing non-flat workpiece surfaces. The workpiece carrier plate can be rotationally driven by a floating drive shaft having a spherical spline head that contacts the workpiece carrier plate at a position close to the workpiece abraded surface to avoid tilting of the workpiece due to the shaft-applied workpiece rotation forces. The workpiece head can allow the workpieces to either float in contact with the abrasive or be held in rigid contact with the abrasive.

Abrasive lapping head with floating and rigid workpiece carrier

Abrasive disk sheet articles having raised islands coated with abrasive have a flexible disk polymer backing. The top flat surfaces of the raised islands are coated with a liquid controlled-thickness slurry mixture of abrasive particles and a polymeric adhesive by use of a magnetic precision-thickness coating-control font sheet having individual open holes that are slightly smaller than the respective raised islands. The magnetic coater font sheet is placed in flat-surfaced contact with the raised island surfaces where each individual font sheet open hole is aligned with a respective island surface. A magnet placed on the non-island surface of the disk polymer backing urges the magnetic coater font sheet into conformal contact with the island surfaces. A squeegee device moved along the font sheet fills and level coats the island tops with a uniform-thickness abrasive slurry mixture. After coating, the font sheet is removed and the abrasive slurry is solidified.

Abrasive coated disk islands using magnetic font sheet

Hard-material, flat-surfaced workpieces such as semiconductor wafers or sapphire disks are attached with vacuum to the flexible elastomeric membrane of a rotatable wafer carrier that allows one surface of the workpiece to be in conformal abrading contact with a moving flat-surfaced abrasive. The elastomeric membrane external wafer attachment surface has a pattern of recessed vacuum grooves where vacuum supplied to the grooves firmly attach the rigid-material silicon wafer in flat-surfaced contact with the membrane. The attached wafer seals the vacuum grooves. A flexible thin metal annular membrane support disk is attached to the membrane within an abrading-pressure chamber where attached drive pins engage matching holes in the wafer carrier provide rotational torque to the wafer and restrain it laterally against abrading forces. Wafer polishing pressure is applied uniformly over the wafer surface. The rotating wafer peripheral edge does not contact a rigid retaining ring during a wafer polishing procedure.

Vacuum-grooved membrane wafer polishing workholder

Hard-material, flat-surfaced workpieces such as semiconductor wafers or sapphire disks are attached with vacuum to the flexible elastomeric membrane of a wafer carrier that allows one surface of the workpiece to be in conformal abrading contact with a moving flat-surfaced abrasive. The elastomeric membrane external wafer attachment surface has a pattern of recessed vacuum grooves and vacuum is supplied to the grooves to firmly attach the rigid-material silicon wafer in flat-surfaced contact with the membrane. The attached wafer seals the vacuum grooves and also provides lateral stiffness to the center portion of the membrane. An outer annular extension of the flexible elastomer membrane maintains the wafer at its original membrane-centered location when abrading forces are applied to the rotating wafer. The rotating wafer peripheral edge does not contact a rigid retaining ring during a wafer polishing procedure. Fixed-abrasive disks or raised-island abrasive disks are attached to a rotatable flat-surfaced platen.

Vacuum-grooved membrane abrasive polishing wafer workholder

Hard-material, flat-surfaced workpieces such as semiconductor wafers or sapphire disks are quickly attached with vacuum to a rotatable floating workpiece carrier. Fluid pressure in a sealed chamber applies uniform abrading pressure over the full abraded surface of the workpieces. A flexible diaphragm is used to form the sealed chamber and the carrier is rotationally driven by a lug-pin device. The floating carrier is horizontally restrained by a center-post device that provides rigid lateral support against abrading forces. Tilting of the floating carrier is provided by a spherical bearing. The abrading system can be operated at the very high abrading speeds used in high speed flat lapping with raised-island abrasive disks. Vacuum can also be applied to the sealed chamber to quickly move the workpiece away from the abrading surface. A mode of providing rigid parallel-surface abrading of a workpiece can be activated by simply applying vacuum to the sealed chamber.

Flexible diaphragm post-type floating and rigid abrading workholder

A bottle rocket launcher comprises a long hollow tube barrel having an tube-axial sealing valve that has a rotary cylindrical or spherical valve member where the valve is attached at the breech end of the launcher barrel. The rocket launcher can be angled up to a near vertical position with support legs. In use, a bottle rocket can be partially inserted into the valve passageway that is held open. The flammable rocket fuse is lit and the bottle rocket is dynamically inserted by hand contact with the rocket stick into the barrel inside chamber body to a position that is beyond the valve member. The valve is rotated into a valve-closed position while the rocket fuse is burning. When the bottle rocket powder is ignited by the burning fuse, the burning exhaust gases thrusts the bottle rocket along the inside of the barrel tube and propels it into the sky in the direction that the launcher barrel is pointed. The rocket exhaust gasses are all restricted to the valve sealed interior confirms of the launch barrel, which protects the operator from the gases or from a premature explosion of the rocket. The launch tube may be independently supported on the surface of the ground or the launch tube may be used as a hand-held device.

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Maplewood, MN, United States of America

Cameron M Duescher