Takeshi Kinsho

Use of Mixture Designs to Investigate Contribution of Minor Sex Pheromone Components to Trap Catch of the Carpenterworm Moth, Chilecomadia valdiviana

Field experiments were carried out to study responses of male moths of the carpenterworm, Chilecomadia valdiviana (Lepidoptera: Cossidae), a pest of tree and fruit crops in Chile, to five compounds previously identified from the pheromone glands of females. Previously, attraction of males to the major component, (7Z,10Z)-7,10-hexadecadienal, was clearly demonstrated while the role of the minor components was uncertain due to the use of an experimental design that left large portions of the design space unexplored. We used mixture designs to study the potential contributions to trap catch of the four minor pheromone components produced by C. valdiviana. After systematically exploring the design space described by the five pheromone components, we concluded that the major pheromone component alone is responsible for attraction of male moths in this species. The need for appropriate experimental designs to address the problem of assessing responses to mixtures of semiochemicals in chemical ecology is described. We present an analysis of mixture designs and response surface modeling and an explanation of why this approach is superior to commonly used, but statistically inappropriate, designs.

Focus improvement with NIR absorbing underlayer attenuating substructure reflectivity

Process dependent focus leveling errors occur in photolithography when there is unpredicted reflectivity originating from multilayer structures on the fully integrated process wafer. The typical wavelength used in optical focus sensors is in the near infrared (NIR) range which is highly transparent to most dielectric materials. Consequently, the reflected light from underlying structures perturbs the accuracy of the leveling signal reflected from resist surface. To alleviate this issue, air-gauge focus sensors have been used to measure the wafer surface topography for an in-situ calibration to correct the focus leveling error. Using an air-gauge sensor is a slow process and a throughput detractor. Therefore, an NIR-absorbing underlayer has been developed for easy insertion into existing resist coating processes. It has been demonstrated that the air-gauge sensor can be turned off without showing any degradation in leveling data or litho performance on back end of line (BEOL) integrated wafers.

Newly developed alternating-copolymer-based silicon-containing resists for sub-100-nm pattern fabrication

Silicon containing bi-layer resist systems for 193nm lithography have been developed for sub-100nm pattern fabrication. Lithographic characteristics of thin film top layer resist show the advantages of high resolution and wide process window. Thick under-layer covers substrate topography with minimum reflectivity and provides sufficient etch resistance for substrate etching. Alternating-copolymers have been employed as backbones of silicon containing resists polymers. Several kinds of functional silicon containing olefins have been synthesized and polymerized to form alternating copolymers. Structural properties of alternating copolymer and hydrophobicity of the silicon containing groups effectively reduced micro swelling in developer and minimized line edge roughness. Discrimination enhancement and acid diffusion control were investigated to achieve high resolution and small proximity pattern size bias. As a result, rectangular 100nm dense line patterns with small line edge roughness are delineated by the newly developed silicone containing resist, using 193nm scanner of NA value of 0.68 and COG-Mask. Characteristics of oxygen reactive ion etching resistance onto the new alternating polymers will be also discussed.