Poly , resists patterns

Figure 24. SEM of poly(TTF-styrene) resist patterns produced by exposure (10 pC/cm2) to 20 kV electrons. (Reproduced by permission from Ref. 145.)...

Development of Resist Patterns. Development was done in AZ2401 developer diluted with 2 to 5 times its volume of water AZ2401 is an aqueous solution of KOH with a surfactant. When the resist films were exposed to electron beam doses of 5 iC/cm2 at 25 keV, it usually took 1.5 to 2.0 min for complete development of the images using a diazo-naphthoquinone sensitizer with o-chloro-cresol-formaldehyde Novolak resin in (1 3) AZ2401/water developer. With poly(2-methyl-l-pentene sulfone) the chlorinated Novolak resin exposed to I juC/cm2, it took 2.0 min in (1 4) AZ2401 developer for complete image development. 

Figure 8. Negative tone resist patterns obtained with a matrix resist of poly(2-methyl-l-pentene sulfone) and Varcum resin.

Figure 11.12 Evolution of a bubble defect formed at (a) resist coat, (b) through development, and (c) patterning with ASML PAS5500/300 KrF stepper. Unexposed resist loss for the UTRfilm was 6-10 nm. The poly-Si patterns are 180-nm lines and spaces. Film thickness was 100 nm. ...

To improve the thermal properties of resists and prevent thermal deformation of resist pattern profiles during the dry etching process, where the temperature of the wafer often exceeds the deformation temperature of untreated resist, UV radiation curing that results in cross-linking is sometimes used. DNQ/ novolac, poly (hydroxy styrene), acrylate, alicyclic, and a whole host of other... 

We also evaluated contact an es on various device substrates (Si02, Al, poly Si, TiN) and measured minimum dot i-line resist pattern size fabricated on each substrate using each adhesion promoter. 

Acrylate polymers slowly undergo chain scission upon irradiation with uv light and electron beams. While this property has been used to advantage [acrylic polymers such as poly(methyl methacrylate) have seen use as high resolution but low sensitivity electron beam and DUV resists], in this instance it is undesirable as it compromises plasma etch resistance, and complicates the metrology of acrylate resist patterns when using scanning electron microscopy (112). 

Ordinary novolak, as discussed in Sect. 8.2, has a low thermal flow stability. During the bake treatment (120 °C), which is normally applied to developed resist patterns, thermal flow leads to deformation. Although this problem can be solved by hardening the pattern by chemical or physical means (see Sect. 3.2), many phenolic polymers with high T, have been studied as replacements for the novolak resin. For example poly (vinyl phenol) (T 160-180 °C) has been utilized in a commercially available... 

A photooxidative scheme has been developed to pattern sub half-micron images in single layer resist schemes by photochemical generation of hydrophilic sites in hydrophobic polymers such as poly(styrene) and chlorinated poly(styrene) and by selective functionalization of these hydrophilic sites with TiCU followed by O2 RIE development. Sub half-micron features were resolved in 1-2 pm thick chlorinated poly(styrene) films with exposures at 248 nm on a KrF excimer laser stepper. The polymers are much more sensitive to 193 nm (sensitivity 3-32 mJ/cm2) than to 248 nm radiation (sensitivity -200 mJ/cm2) because of then-intense absorption at 193 nm. 

This work on organometallic resists was extended by MacDonald et al. (126) to include poly(trimethylstannylstyrene) and poly(trimethylsilylstyrene) together with copolymers of these materials with p-chlorostyrene. The sensitivity of the stannyl derivative to electrons is reported to be 0.5 / 2, and the copolymer with p-chlorostyrene could be patterned in the deep UV at a dose of 10 mJ/cm2 at 254 nm. The materials show excellent oxygen RIE resistance due to the formation of involatile oxides of the metals on the surface of the pattern. 

Figure 7 shows the SEM photographs of line and space patterns using an exposure of 10 / 2. The smallest line and space width of the 2LR pattern that was well-resolved is 0.2 . Figure 8 shows the resolution of 1LR poly-a-methylstyrene (aM-CMS) pattern and the 2LR using SNR/AZ resist. In the case of aM-CMS that is known as a high resolution negative electron resist in 1LR, the smallest line and space width is 0.4 jtm with 0.6 jim of resist thickness... 

Butadiene is used primarily in the production of synthetic rubbers, including styrene-butadiene rubber (SBR), polybutadiene nibber (BR), styrene-butadiene latex (SBL), chloroprene rubber (CR) and nitrile rubber (NR). Important plastics containing butadiene as a monomeric component are shock-resistant polystyrene, a two-phase system consisting of polystyrene and polybutadiene ABS polymers consisting of acrylonitrile, butadiene and styrene and a copolymer of methyl methacrylate, butadiene and styrene (MBS), which is used as a modifier for poly(vinyl chloride). It is also used as an intermediate in the production of chloroprene, adiponitrile and other basic petrochemicals. The worldwide use pattern for butadiene in 1981 was as follows (%) SBR + SBL, 56 BR, 22 CR, 6 NR, 4 ABS, 4 hexamethylenediamine, 4 other, 4. The use pattern for butadiene in the United States in 1995 was (%) SBR, 31 BR, 24 SBL, 13 CR, 4 ABS, 5 NR, 2 adiponitrile, 12 and other, 9 (Anon., 1996b). 

Mixtures of powders of poly(vinyl chloride) (FVC) and various metals were compacted at a pressure of 10,000 psig at 120-130°C. The compacts appear to be strong, and density measurements show the porosity to be <1.5%, Electrical resistivity is reduced, from a value for unloaded FVC of about JO25 Clem, to < JO"1 Clem by a fractional volume loading of nickel or copper as low as 0.06. Microscopic examination of polished sections of the compacts show the metallic particles to be segregated around zones of unpenetrated polymer which correspond in size to the initial particles of FVC. The pattern of segregation favors the formation of continuous chains of metallic particles at unusually low volume loadings. 

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