Non-chemically amplified resists offer advantages over chemically-amplified (CA) resists because they are less susceptible to temperature variations and contaminants. In order for non-CA resists to be viable, they have to perform lithographically at an equivalent level with the CA resists from the points of view of quantum yield, resolution, and etch resistance.We report here on new non-CA resists based on polymer esters that undergo deesterification to the corresponding acids upon exposure to UV, x-ray and e-beam radiation. The efficiency of the radiation reaction is surprisingly high. The resulting poly acids are base soluble and can be employed as positive working resists. The resists are composed of polymers and copolymers of methacrylate esters. The sensitivity of one derivative to x-ray is 75 mJ/cm(2) and to e-beam is 1.0 mu C/cm(2) at 10 KV. Best resolution obtained was 125 nm with x-ray radiation.

This paper describes a technique to determine the presence and uniformity of Helium in the mask/wafer gap of x-ray lithography steppers by utilizing the oxygen sensitive resist polychlorostyrene (PSC). Results obtained at the IBM Advanced Lithography Facility using a SUSS stepper and the HELIOS superconducting synchrotron storage ring are presented.

One method of improving the performance of silicon integrated circuits is to reduce the delay of the interconnections between individual devices by reducing the resistance and capacitance of the connection. Even though it is possible to replace the commonly used aluminium conductors in current interconnection technologies with copper, no company has done so in production, due to a series of unanswered questions pertaining to the cost and leverage of doing so. This paper will attempt to elucidate the performance and cost benefits of this approach and will try to identify and resolve some of the important integration issues related to the inclusion of polymers and copper conductors into ULSI interconnections.<>

Multilayer copper/polyimide interconnect structures were fabricated using a reactive-ion-etching-based lift-off technique. Conductor cross-sectional area control, planarity, and a gap-free structure were made possible by the use of a novel siloxane-polyimide. The resultant structure consisted of two signal wiring layers between two ground planes with a nominal impedance of 40 Ω. Although redundant metallization processes were found to repair open lines, they resulted in an increase of the number of processing steps and could result in an increase of defects. Stud chain structures were found to survive cooling to 77 K with very little change in their characteristics, while heating of the copper interconnections to 350°C in a reducing environment reduced their resistance by 3%

Organosilicon groups can be incorporated into photoresists, rendering them resistant to erosion by oxygen plasmas. This process, known as silylation, can be implemented using either liquid or vapor sources. A comparison of these two methods was performed using mono-,di- and trifunctional organosilicon compounds with reactive Si-N-bonds. Among the four monofunctional compounds studied, hexamethyldisilazane is about 10 times less reactive in silylation of AZ 4110 films at normal pressure (126°C) compared to tetramethyldisilazane or dimethylaminotrimethylsilane. Mixed vapors of difunctional compounds (10% of bis/dimethylamino/methylsilane) and toluene silylate resist films at 111°C at a high rate forming crosslinked materials with an increased stability in O2 plasmas (etch rate of about 50 A/min after 2 min silylation). Trifunctional compounds (tris/dimethylamino/methylsilane) do not silylate resist films due to the formation of a crosslinked diffusion barrier on the surface. Difunctional silylating agents like bis(dimethylamino)dimethylsilane effectively silylate resist films at 80–85°C in toluene soluyion (which does not contain any diffusion promotors like NMP) without any distortions or thickness loss. The chemistry of silylation is discussed.

Different types of polyfunctional organosilicon compounds (chloro-, alkoxy-, acetoxysilanes, linear and cyclic silazanes and silylamines) were studied as silylating agents in the diffusion limited heterogeneous silylation process. It was shown that compounds with reactive silicon nitrogen bonds were most effective at silylating AZ4110 resist. Surprisingly, it was found that the higher the organosilicon compound reactivity, the lower the degree of silylation of the photoresist. One of the most effective silylating agents was found to be bis (dimethylamino)dimethylsilane (BDAMS). The chemistry of silylation of both novolak resins and 1,2,5-naphthoquinone diazo type photoactive compounds (PAC) leading to the formation of crosslinked materials is discussed. The formation of triazine derivatives was also detected. Photoresist images which were UV irradiated at 365 nm after exposure and development were found to be more amenable to silylation than those which had not.