Advanced Resist Processing Techniques

How the balance between the above-named requirements are struck in each of the major advanced resist-processing schemes in use today is discussed below, along with the advantages and drawbacks of each technique. In particular, we discuss the material basis of the resolution limit issues of resists, especially as they concern those based on chemical amplification systems, since these constitute the majority of resists in use in advanced lithographic processing today. 

The plasma-assisted shrink techniques (e.g., MOTIF ) use plasma to deposit a thin film that conformally coats contact holes and spaces printed in resists, which on dry etching result in smaller contact holes and spaces. In the remainder of this section, we provide a more detailed treatment of the postexposure-hased singlelayer exposure techniques employed in advanced resist processing. 

Regarding ozonization, it is only applied in a limited number of WWTPs after secondary treatment [61]. Several investigations have proven that it is a very effective technique to eliminate pharmaceutical [25, 62, 63]. Oxidation reactions take place due to direct reaction with ozone (03), which are very selective or with free OH radicals, which are generated by ozone decomposition and are very powerful and not selective oxidants. In advanced oxidation processes, 03 is completely transformed onto OH radicals and they are recommended when compounds are ozone resistant. 

M.R. Hendrick, T.J. Hwang, H. Shao, H.G. Hornis, J. Thomas, and A.T. Hunt, Chrome Replacement and Thermal Corrosion Resistant Coatings Via Open Atmosphere CCVD Processing in 3rd Annual Advanced Techniques for Replacing Chromium, Seven Springs, Pennsylvania, 1996. 

As mentioned in Chapter 1, the present state of CMP is the result of the semiconductor industry s needs to fabricate multilevel interconnections for increasingly complex, dense, and miniaturized devices and circuits. This need is related to improving the performance while adding more devices, functions, etc. to a circuit and chip. This chapter, therefore, discusses the impact of advanced metallization schemes on the performance and cost issues of the ICs. Our discussions start with the impact of reducing feature sizes on performance and the need of various schemes to counter the adverse effect of device shrinkage on the performance of interconnections. An impact of continued device shrinkage on circuit delay is discussed. Then the need of low resistivity metal, low dielectric constant ILD, and planarized surfaces is established leading to the discussion of CMP. Finally various planarization techniques are compared to show why CMP is the process that will satisfy the planarity requirements of the future. 

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