Plasma resistance

Good Thermal and Oxidative Stability High Permeability to Gases Excellent Atomic Oxygen (Plasma) Resistance Physiological Inertness (Biocompatibility)... 

In an effort to improve PMMA s photosensitivity further, methyl methacrylate has been copolymerized with higher percentages of the a-keto-oxime methacrylate and terpolymerized with varying amounts of methacrylonitrile. The resulting effects on resist properties, e.g., sensitivity, contrast and resolution, and plasma resistance, are reported here. The terpolymers are up to 85 times more sensitive than PMMA, and retain its high resolution characteristics. 

Plasma Resistance. Another criterion that a resist must satisfy is that it be resistant to the processes used to transfer the relief image into the substrate. One of the more... 

The photosensitivity of PMMA is significantly enhanced by the incorporation of 10 to 40 mole% 3-oximino-2-butanone methacrylate. Terpolymerization with methacrylonitrile increases that sensitivity still further, P(M-OM-CN) (69 16 15) being 85 times more sensitive than PMMA on exposure to the full output of a 1000 watt mercury lamp. Upon addition of external sensitizers, this sensitivity may be increased by an additional factor of 2 to 3. The high resolution characteristics of PMMA have been retained and the polymers in question show good plasma resistance. 

The inorganic resist system is unique with respect to optical sensitivity coupled with 02 plasma resistance. Most organic polymers do not possess sufficient plasma etching resistance to withstand oxygen plasma etching of... 

As already mentioned, the induced current Ipl heats the plasma due to joule losses which are proportional to the plasma resistance. With increasing temperature the plasma resistance decreases and the ohmic heating becomes less effective. Theoretical analysis shows that the maximum temperature which can be reached in this way is below 2 keV, i.e. the plasma cannot enter the ignition region of 5 keV4. Therefore,... 

Some work that was considered to show severe acquired plasma resistance to activated protein C among users of third-generation (as opposed to second-generation)... 

Remuzzi G, Galbusera M, Salvadori M, et al. Bilateral nephrectomy stopped disease progression in plasma-resistant hemolytic uremic syndrome with neurological signs and coma. Kidney Int 49 282-6,1996. 

Last two decades were period of a transition from a liquid toward dry etching. That is why plasma resistance is among the most important properties of a photoresist. In the case of fluorine-containing plasmas, etch resistance... 

It is well known that insertion of silicon-containing groups into a polymer enhances its plasma resistance greatly. The rate of a reactive ion etching in oxygen (RIE in O2) in the stationary state, P, is proportional to the ratio of the silicon atom mass densities in the polymer, ppoi., and in Si02, Poxide ... 

The silylation should be controlled carefully because of cracking occurring when the content of silicon atoms incorporated into the photoresist is large enough and of not sufficient plasma resistance against RIE in O2, when silylation process is stopped earlier than it should be. 

Current interest in siloxane polyimides is triggered by opportunities for such materials in military, aerospace and electronic applications as coatings, films, adhesives, molding compounds and composite matrix materials which are subject to demanding operating conditions. These polymers offer advantages such as excellent interlevel adhesion, plasma resistance, low water absorption, and stability at high temperatures. 

The reticulation problem is also encountered in the plasma resist image stabilization method (PRIST) (38) where the crosslinking reactions are more superficial than in UV-hardeniog. In PRIST, resist images are exposed to a CF4 plasma for a short period, providing a surface cross-linked by interaction with the reactive environment. The oxidation and fluorine incorporation are limited to a very shallow surface. 

The different versions in existence may be classified according to Spalvins [386] as to the media, evaporation source and mode of transport into two categories low vacuum ion plating (self-sustained glow discharge plasma) resistance evaporation electron-beam evaporation induction evaporation sputtering... 

It should be pointed out that although PGMA and its derivatives are highly sensitive and have excellent resolution, they suffer from poor plasma etch stability. This led to the investigation of the plasma-resistant polystyrene and some of its derivatives as electron-beam resists. ... 

W.H.L. Ma, Plasma resist image stabilization technique (PRIST) update, Proc. SPIE333,19 (1982). P.A. Ruggiero, Positive photoresist polymerization through pulsed photomagnetic curing, Solid State Technol. 27(3), 165 (1894). 

A major drawback of the PMIPK resist system is its relatively low plasma resistance, even lower than that of PMMA. An approach that has been employed to improve its etch resistance is to blend it with more resistant aromatic polymers, but this is at the expense of decreased sensitivity. ... 

Plasma resistance at the critical point becomes equal to the external one, and maximum value of the discharge power equals half of the maximum generator power. When the arc length exceeds the critical value (/ > hnt), the heat losses wl continue to grow. But the power from the power supply cannot be increased anymore, and the gas temperatme rapidly decreases. Plasma conductivity can still be maintained by electron temperatures ( 1 eV) and stepwise ionization (Fridman et al., 1999). The fast equilibrium-to-non-equilibrium transition is due to the increase of electric field E = w/1 and electron temperature T ... 

Plasma resistance of organic polymers can increase significantly due to the presence of aromatic and heteroatomic groups. So if a resist could be made such that after exposure, the exposed area contained more of these groups than the unexposed area a differential plasma etch rate would be achieved leading to selective development (Figure 5.49). 

Iwasawa J, Nishimizu R, Tokita M, Kiyohara M, Uematsu K (2007) Plasma-resistant dense 5dtrium oxide film prepared by aerosol deposition process. J Am Ceram Soc 90 2327-2332... 

The main goal of this step is the complete removal of the resist without affecting the wafer surface. Two methods are used wet stripping (the use of either solvents, which dissolve the resists, or oxidisers that transform the resist into carbon dioxide and waste) and plasma resist stripping. 

Resists having the structure [37] shown in Figure 6.20 have good oxygen plasma resistance, presumably due to the conversion of Si to SiOj. 

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