Thick resists resolution determination

All the results were confirmed by investigations with both back- and front-side illumination [37]. In this study, which also describes theoretical aspects, a final resolution of 17 pm for an epi-structure was achieved, which consisted of a thin layer (3 pm, specific resistance of lOQcm) and a thick silicon substrate (0.38 pm, with low specific resistance of 0.005-0.02 Q cm). Instead of using a pattern grid on the front-side to study the smallest possible resolution, in this work the sensor chip was coated half with a metal layer. This forms on the covered side a metal-insulator-semiconductor (MIS) structure. The light pointer was moved from the metallised area to the uncovered area and the resolution was determined at the borderline by measuring the photocurrent that depends on the diffusion length of the carriers. Since, for the assumption that the diffusion length is the main decisive and critical parameter for the amount of carriers which could reach the metal-covered part of the semiconductor substrate from a specific distance, the calculation of the minimal resolution was experimentally observed. 

Clearing doses were determined by immersing the wafers in a strong solvent (acetone) for two minutes. Standard dip development was carried out by immersion in MIBK (methyl-isobutyl-ketone) at 21°C for time increments from one minute to ten minutes. The dissolution rate was calculated from thickness loss, measured using a Nanospec, and development time. SEM examination of test structures was used to evaluate the resolution of the resist under the different processing conditions. Unless specifically mentioned, each experiment showed that 0.5ym features could be resolved in the resist. 

We used high resolution resists of ZEP520 (Nippon Zenon Co.) and calixarene (Tokuyama Co.) as positive and negative resists, respectively. Furthermore, we used very thimer resists. Their thicknesses are about 70 nm and 15 nm, respectively. The thicknesses were determined by whether we observe... 

The multi-sensing technologj-, based on simultaneous high-resolution force and electrical and acoustic measurements, allows for ver> accurate determination of both delamination/ adhesion and scratch resistance of both thin and thick coatings. Using the test tools with higher contact area (or length), like micro-blade or ball, may allow for more repeatable results than those obtained with sharp styluses. 

The contrast, y, is related to the ability of a polymer to give vertical sidewalls. Resolution (defined as the smallest linewidth which can be achieved) depends on the contrast. The parameters are determined from the sensitivity curve of the resist, which expresses the normalised film thickness, e/eg (e is the thickness after development and irradiation, eg is the initial thickness of the resist), as a function of logjg (Dose) (Figures 6.4(a) and 6.4(b)). 

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