Robert Dennis Grejda

Functional tolerancing using full surface metrology

This paper highlights two examples of the use of full surface metrology to allow for functional tolerancing of components in the areas of EUV lithography (reticle characterization) and DUV precision lens manufacturing (lens holder metrology). For both examples, the measurement of the full surface is a key enabler to understanding the critical characteristics to control and tolerance for functionality or performance. Interferometric techniques are used to provide high resolution and accurate measurements for both examples. Subsequently, this data can be used to identify the surface characteristics that contribute to the end functionality and provide a means for deterministic correction or compensation.

Advancements in adhesive mounting of optics

Adhesive mounting of lenses can allow flexible position control of each optical element, low stress, low part count, and precise alignment of lens assemblies in addition to high durability with respect to thermal expansion, shock, and vibration. Historic implementations of this method carried risk of UV degradation, photo contamination, long term stability, and long assembly cycle times. Others have developed non-adhesive friction/contact approaches to mount lenses but with significant compromises in durability and product cost. These two methods are compared and an optimal approach to achieve high lens mounting durability, low cycle time and negligible photo-contamination is demonstrated. Durability of this adhesive mounting solution will be established with examples including shock and vibration, mechanical stress decoupling factors, and optical stability over a wide range of shipping temperatures.