Analysis and Modeling of Polysilicon Critical Dimensions

The objective of the project was to evaluate polysilicon CD etch bias as it was affected by etch time, measurement feature within the exposure field, and the product being measured. Characterization of the trends has generated a summarizing model that uses etch time, measurement feature, and product type as significant factors in determining polysilicon CD etch bias. Etch time was found to be a continuous factor, while measurement site and product type were categorical. Measurement Site A was found to be independent of measurement Site B, independent of Site C, etc., as well as Product 1 was found independent of Product 2. When tested with JMP Statistical software the generated model produced an R-sq Adj. =0.96. A comparison of modeled values with collected data for several different combinations of conditions showed a maximum difference of 6% on a normalized scale

Dynamic load capacities of graphite fiber: Polyimide composites in oscillating plain bearings to 340 C (650 F)

Load capacities were determined for plain spherical bearings with self-lubricating spherical elements of graphite-fiber-reinforced-polyimide, and for plain cylindrical bearings with thin-wall liners of the composite in the bearing bores. Composites consisted of a 1-to-1 weight ratio of graphite fibers and polyimide. Oscillation was at an amplitude of + or - 15 deg at a frequency of 1 hertz. Bearings with composite ball material had a load capacity of approximately 69 MN/sq m (10 000 psi) at room temperature 25 MN/sq m (3600 psi) at 340 C (650 F). Bearings with thin-wall composite liners had much higher load capacities of 280 MN/sq m (40 000 psi) at room temperature amd 240 MN/sq m (35 000 psi) at 320 C (600 F). Friction coefficients were in the range of 0.12 to 0.19. The addition of 10 wt.% graphite fluoride solid lubricant to the composition of the thin-wall liners reduced friction coefficients into the range of 0.10 to 0.12

Composite Reflective/Absorptive IR-Blocking Filters Embedded in Metamaterial Antireflection Coated Silicon

Infrared (IR) blocking filters are crucial for controlling the radiative loading on cryogenic systems and for optimizing the sensitivity of bolometric detectors in the far-IR. We present a new IR filter approach based on a combination of patterned frequency selective structures on silicon and a thin (50 $\mu \textrm{m}$ thick) absorptive composite based on powdered reststrahlen absorbing materials. For a 300 K blackbody, this combination reflects $\sim$50\% of the incoming light and blocks \textgreater 99.8\% of the total power with negligible thermal gradients and excellent low frequency transmission. This allows for a reduction in the IR thermal loading to negligible levels in a single cold filter. These composite filters are fabricated on silicon substrates which provide excellent thermal transport laterally through the filter and ensure that the entire area of the absorptive filter stays near the bath temperature. A metamaterial antireflection coating cut into these substrates reduces in-band reflections to below 1\%, and the in-band absorption of the powder mix is below 1\% for signal bands below 750 GHz. This type of filter can be directly incorporated into silicon refractive optical elements

Ablation debris control by means of closed thick film filtered water immersion

The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types

Chelonian Brain-Membranes, Brain-Bladder, Metapore and Metaplexus

The chelonian brain is not too small to be studied macroscopically. It is easily removed from the skull. Minute surface details and the cell structure can be easily observed

A Comparative Study of the Structure and Origin of the Yolk Nucleus

The question as to the comparative structure and origin of the yolk nucleus involves several other problems: 1. Is the yolk nucleus a normal element of the egg cytoplasm, or is it associated with pathological states of the egg, or is it an artefact due to reagents? 2. Is there a necessary connection between one form and another such that one can be derived from the other? 3. Is it an amorphous chemical substance or does it possess anything suggesting permanence of structure? 4. Does it arise de novo or is it a modification of something similar existing in the cytoplasm of the oogonium? 5. Does it arise from chromatin eliminated from the germinal vesicle? 6. Is it due to cells entering the egg? The answer to these questions will determine whether or not it is important

Spermatogenesis of the Butterfly, Papilio rutulus

For a number of years I have been studying the spermatogenesis of Papilio rutulus (pl. 12, fig. 1) not ,with any one single problem especially in view, but with the aim of ascertaining the entire life history of its sperm cell, its various phases of development, its mode of growth and differentiation, the history of its several parts, and its relation to the organism

Organization and Polarity of Protoplasm

In higher forms of life, we usually concede the presence of an organ specialized for the performance of a function. In these higher forms coordination of organs, which entails a regular sequence in their functions, is readily made out; and it seems a mere platitude to say, of these, that organization determines the functions of the organism. To what extent can functions exist in the absence of organization; does the one precede the other; or have function and organization developed simultaneously, out of matter devoid of both structure and function? In my studies on the cell, I have kept these problems in mind; and it is my purpose here to present some observations bearing on these questions