Pattern transfer techniques Patterning dose

Due to the extremely short wavelengths of the accelerated electrons, the resolution of the instrument is not due to the radiation diffraction limits but to other effects such as multiple scattering of the electrons in the resist layer and substrate surface, and secondary electron emission [73,75,78]. These, mainly resist dependent, effects are hard to identify in detail but can be controlled to some extent during the exposure. However, it is not just the resolution of the resist which is the controlling factor in the ultimate particle size reached, rather it depends on exposure conditions (dose, beam intensity, etc.), the type of developer and processing technique used, and the way in which the hnal pattern is transferred to the substrate [79]. 

The spacer double-patterning approach has some issues, the main one of which concerns placement accuracy of the features, which requires excellent dose and etch uniformity control. Equally problematic is the fact that the spacers may not stay in place at the proper location after the material to which they are attached (the HM pattern) is removed. Forming acceptable uniform spacer profiles that will yield uniform CDs is not a trivial exercise. In addition, the etch pattern transfer steps, often involving delicate removal of materials adjacent to the spacers, place unusually tight etch process tolerance on this technique, in order to have a successful outcome. 

The Camag Automatic TLC Sampler 4 (ATS 4) is an advanced, fuUy automated, PC-controlled device for sequential application of up to 66 samples from a rack of 2 ml septum-covered vials or 96 samples from well plates (15 05 45 mm height) as spots by contact transfer (0.1-5 xl) or as bands by the spray-on technique (0.5->50 xl) a motor driven dosing syringe sucks up the sample volume and feeds a steel capillary connected to a capillary atomizer. The speed, volume, and X- and Y-position pattern of application are controllable, and a programmable rinse cycle between the applications can eliminate cross-contamination. 

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