Alfred F. Renaldo

Thermally Developable, Positive Tone, Oxygen RIE Barrier Resist for Bilayer Lithography

Poly(4‐trimethylsilylphthalaldehyde) sensitized with triphenylsulfonium triflate develops to the substrate upon postbake. The sensitivity is very high owing to chemical amplification. The resist system does not self‐develop during exposure but the development is achieved simply by heating the image‐wise exposed resist. The thermally developed resist image serves as an oxygen RIE barrier for the pattern transfer in the bilayer resist scheme, providing a new positive‐tone all dry process.

Thick film positive photoresist: Development and resolution enhancement technique

The development of a positive, thick film photoresist consisting of a diazonaphthoquinone sensitizer and a novolac resin is described which has the capability of meeting a wide range of thick film requirements necessary for magnetic recording head fabrication. This photoresist system can coat 4–15‐μm‐thick films over various types of topography on a variety of different metal and dielectric surfaces (copper, Permalloy, and alumina). Moreover, this resist is compatible with copper, permalloy, and gold plating baths as well as different metal etchants. The photoresist can be used to produce images with wall profiles greater than 80° with a resolution capability approaching 2 μm lines and spaces in a 7.5‐μm‐thick film. Process latitude is demonstrated over a wide range of exposure doses and focus positions. Enhancement of thick film photoresist resolution has been achieved using a method which involves the treatment of photoresist films with dilute surfactant solutions. A number of factors have been found to...

Preparation of Acyclic α-Methylene Ketones: Palladium-Catalyzed Coupling of Acid Chlorides with Organotin Reagents

Abstract The reaction of organotin reagents with acid chlorides, catalyzed by palladium (0), provides a general entry to α-substituted unsaturated ketones.

Lithographic performance of a positive photoresist for thick-film applications

The process capability of a commercially available positive diazonaphthoquinone (DNQ) photoresist, SJR 3000 series from Shipley, was evaluated. This photoresist at a film thickness of 7 - 8 microns was found to have a large process latitude and focus budget while maintaining nearly vertical wall profiles. The high contrast found with this thick film photoresist was due to a low loading of a monofunctional DNQ sensitizer which also has a high dissolution inhibition. The photoresist formulation was compatible with both AZ 400K and Microposit (MP) 2401 developers when using either a stepper or scanner exposure system. SJR photoresist was shown to provide an effective photoresist frame for electroplating metals such as copper and permalloy.