Vanguard International Semiconductor Corporation

Haw Yen

Shaw-Tzeng Hsia

Ching-Ying Lee

Shaw-Tseng Hsia

Chih-Cherng Liao

A method for creating manufacturable polycide contacts, for use in advanced semiconductor designs using images as small as 0.35 uM, has been developed. An amorphous silicon film, is used as an underlay, to assist in the growth of an overlying tungsten silicide layer. The tungsten silicide deposition is performed using tungsten hexafluoride and silane, and in conjunction with the amorphous silicon underlay, results excellent step coverage in the narrow contact hole. A nitrogen anneal, using high flow rates, optimizes the adhesion characteristics of the tungsten polycide structure.

Tungsten policide contacts for semiconductor devices

A process, to fill small diameter contact holes with tungsten, without deleterious attack of contact hole liner materials, during the tungsten deposition, has been developed. The process consists of using a titanium nitride barrier layer, overlying a titanium adhesive layer. However the barrier characteristics of titanium nitride are enhanced by subjecting this layer to an anneal cycle in an nitrogen ambient. The annealing produces a more robust barrier in terms of incorporating additional nitrogen into the deposited titanium nitride layer, as well as forming titanium nitride on any underlying titanium, that may be exposed due to defects in the deposited titanium nitride layer.

Optimized tungsten contact plug process via use of furnace annealed

A process has been developed in which small diameter contact holes can be filled with chemically vapor deposited tungsten, without severe attack of the contact hole liner materials. An adhesive layer of titanium, and a barrier layer of titanium nitride are used for the contact hole liner, and are deposited prior to tungsten process. A process consisting of subjecting the barrier layer of titanium nitride to a rapid thermal anneal, in an ammonia ambient, results in enhanced barrier characteristics. The robust titanium nitride layer is now able to survive the tungsten deposition process, and attack form fluorine ions, produced during the decomposition of the tungsten source, tungsten hexafluoride.

Annealing of titanium - titanium nitride in contact hole

A process for fabricating stacked capacitor, DRAM, devices, has been developed in which the surface area of the storage node has been significantly increased as a result of a unique set of deposition and annealing conditions. An amorphous polysilicon layer, used as the upper layer of the storage node, is ramped up in pure nitrogen, and then insitu annealed, to result in a polycrystalline structure, exhibiting significant surface area increases, due to the formation of surface concave and convex protrusions. The increase in storage node surface area allows for increased DRAM capacitance, without the use of larger dimension stacked capacitors, or thinner dielectrics.

Process to form rugged polycrystalline silicon surfaces

A process has been developed that allows small diameter contact holes to be filled with chemical vapor deposited tungsten, without tungsten peeling from the sides of the contact hole. The process consists of initially depositing an adhesive layer of titanium in the contact hole, followed by a rapid thermal anneal cycle, in an ammonia ambient, for purposes of creating a thin, uniform, barrier layer of titanium nitride. The titanium nitride protects the underlying titanium adhesion layer from the by-products introduced during the tungsten deposition, specifically the evolution of fluorine ions resulting from the decomposition of tungsten hexafluoride.

Nitridation of titanium, for use with tungsten filled contact holes

A method for creating manufacturable polycide contacts, for use in advanced semiconductor designs using images as small as 0.35 .mu.M, has been developed. An amorphous silicon film, is used as an underlay, to assist in the growth of an overlying tungsten silicide layer. The tungsten silicide deposition is performed using tungsten hexafluoride and silane, and in conjunction with the amorphous silicon underlay, results excellent step coverage in the narrow contact hole. A nitrogen anneal, using high flow rates, optimizes the adhesion characteristics of the tungsten polycide structure.

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Hsin Chu, Taiwan

Haw Yen