Imtec Acculine, Inc.

Siltech Corporation

Cybeq Systems, Inc.

Imtec Products, Inc.

Kenneth C Struven

Anthony C Bonora

Norm Shendon

Robert E Lorenzini

Robert J Kolenkow

Walter Torbert

In a substrate bath that processes substrate wafers using megasonic energy, a tank that is provided with reflecting surfaces that direct the megasonic energy to those portions of the substrates that would otherwise be sonically shadowed by the cassette that supports the substrates. In one aspect, a pair of curved wall surfaces are formed within the tank, each extending from one side wall to the bottom wall in curvilinear fashion and oriented longitudinally, the paired curved wall surfaces being disposed in laterally spaced, enantiomorpic relationship. The curved surfaces are arranged so that a significant amount of the megasonic energy impinges at an angle less than the critical angle, so that the energy is reflected in a diverging field that intersects the substrates and strikes those portions of the substrates that are shadowed by the cassette structure. Thus the megasonic cleaning, (etching or processing of the substrate) process is improved significantly.

Megasonic bath

A cassette for supporting electrical component substrates in a megasonic processing bath includes a pair of end panels spaced apart longitudinally, a pair of side rails extending longitudinally along opposed sides of the substrate cassette, and at least one bottom support extending between lower portions of the end panels. The supports include a plurality of shallow channels extending laterally therein and spaced regularly therealong to receive edge portions of the substrates. The side rails and bottom supports of the cassette are all formed of plate components that are dimensioned to transmit the maximum amount of the megasonic energy projected into the processing bath, so that the components do not cause sound-shadowing of the substrates supported in the cassette. The side rails and bottom supports are formed of narrow plates having a thickness equal to an integer multiple (i.e., 1, 2, 3, etc.) or an even fractional (i.e., &frac12;, &frac14;, etc.) number of wavelengths of the ultrasonic energy in the material that comprises the side rails and bottom supports. The wavelength matching dimensions of the structural components couples the sound energy into the quartz to a maximum extent, and it is transmitted through the quartz to the liquid bath as well as to the substrates supported by the structural components. In addition, the narrow plate components may be tilted to be non-horizontal to shed detrimental bubbles that may form in the liquid of the megasonic bath.

Substrate cassette for ultrasonic cleaning

A bath in which articles are processed by immersion in hot liquid chemicals has a chemical receptacle seated in a casing. Wetting of internal components in the casing, such as heating elements and thermal insulation, is prevented by a seal between the receptacle and the rim of the casing. The otherwise exposed seal is isolated from the external environment of the bath by a barrier of flowing water. The water flow shields the sealing material from corrosive chemical drips and fumes and also has a cooling effect which decreases thermal expansion of components in the region of the seal and thereby reduces structural stresses.

Apparatus and method for protecting chemical bath seals

A polishing head for polishing a semiconductor wafer is described. The head design enables a wafer retainer to float during polishing and yet extend beyond a wafer carrier to define a pocket for the wafer and thereby facilitate wafer changing. The head construction also enables the carrier to be selectively projected beyond the retainer so that the surface of the carrier is easily accessible for changing an insert or the like. The head uses a positive air pressure to press the wafer against the polishing pad and the head includes interfering mechanical constructions which provide the positions mentioned above.

Wafer polisher head having floating retainer ring

A polishing apparatus has a conventional carrier with a plurality of floating subcarriers. The benefits of single wafer polishing are achieved with the economies of multiple wafer polishing by adding the plurality of floating subcarriers to the conventional carrier. Each subcarrier has a single wafer adhered to its underside. Axial freedom is provided to duplicate the dynamics of single wafer polishing. The required axial freedom is obtained by axially loading each subcarrier via a mechanical spring or via pneumatic/hydraulic devices. In two variations, each subcarrier is also allowed auto-rotational freedom. In another two variations, the subcarriers are rotationally driven. In all variations, the wafers adhered to the floating subcarriers are substantially uniformly polished and the total indicated reading of the maximum deviation on the wafer surface is improved.

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San Carlos, CA, United States of America

Kenneth C Struven