Bell Telephone Laboratories

Eugene D Feit

Larry F Thompson

Cletus W Wilkins, Jr

Murrae J Bowden

Newton Schwartz

Marguerite E Wurtz

Radiation sensitive negative resists with requisite stability for dry processing of integrated circuits are polymerized from aromatic moieties containing halogen atoms. Halogen-aryl bridging, generally carbonaceous, increases sensitivity to radiation. Exemplary materials, copolymers prepared from aromatic and glycidyl methacrylate (GMA) comonomers, are suitable for direct processing of large-scale integrated circuits. While electron beam patterning is contemplated both for direct processing and mask making, radiation such as X-ray and deep u.v. may be used.

Fabrication based on radiation sensitive resists of halo-alkyl styrene

Fabrication based on radiation sensitive resists and related products

Fabrication of fine dimensioned circuits, e.g., VLSI includes at least one lithographic step dependent upon members of a particular category of polymer resists. Such resists, generally negative acting, are characterized by high contrast due to unusually narrow molecular weight distribution of the polymer molecules. This distribution is in turn dependent upon choice of a base polymer which is itself characterized by narrow molecular weight distribution due to 'living polymerization' (solution anionic, polymerization). Functionalization of such base polymer is designedly such as to retain narrow distribution. Chlorinated polystyrene is exemplary of the resist category.

Lithographic fabrication with treatment of 'living polymer'

A flame retardant, flexible, solder resistant covercoat has been formulated based on dichloropropyl acrylate.

Cover coatings for printed circuits

Negative resist compositions are based on carbonaceous polymers with substituent branches containing epoxy groupings. Exemplary materials which include, for example, a copolymer of glycidyl methacrylate and ethyl acrylate in which epoxy groupings are unesterified show high sensitivity, for example, to electron radiation and to X-rays. Resolution is sufficient to permit expedient fabrication of detailed resist patterns for integrated circuits. High adherence permits use of acid or base reagents and thermal stability permits use of ion milling for circuit fabrication.

Process using radiation curable epoxy containing resist and resultant

A technique is described for depositing organic layers down to a fraction of a monolayer thickness upon insulating substrates by non-vacuum deposition techniques which permit the subsequent deposition of mechanically stable adherent films of b.c.c. tantalum of low resistivity. The deposited films permit the fabrication of low cost, high frequency performance tantalum thin film capacitors.

Technique for nucleating b.c.c. tantalum films on insulating substrates

Several materials have been proposed as protective coatings for magnetic sensing heads in magnetic tape readers. Some of these, known for hardness, are not very wear resistant. Others that seem to wear well tend to spall. The invention is a polymer coating that wears exceptionally well, can be formed conveniently to encapsulate the magnetic sensing elements, can be photocured and therefore photopatterned, and is inexpensive. The polymer is composed of a mixture of urethane-modified acrylates and methacrylates.

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Berkeley Heights, NJ, United States of America

Eugene D Feit