Search Results for optical

This chapter provides a general description of materials and methods for manufacturing high-performance composites. The materials covered are polymer matrices and prepreg materials and the methods include infusion processes, composite-toughening methods, matrix-toughening methods, and dispersed-phase toughening. In addition, the chapter provides information on interlayer-toughened composites and honeycomb or foam structure composite materials. It also discusses the processes in optical microscopy of composite materials.

Moore's Law has driven many degree circuit features below the resolving capability of optical microscopy. Yet the optical microscope remains a valuable tool in failure analysis. This article describes the physics governing resolution and useful techniques for extracting the small details. It begins with the basic microscope column and construction. The article discusses microscope adjustments, brightfield and darkfield illumination, and microscope concepts important to liquid crystal techniques. It also discusses solid immersion lenses, infrared and ultraviolet microscopy and concludes with laser microscopy techniques such as thermal induced voltage alteration and external induced voltage alteration.

Time-domain based characterization methods, mainly time-domain reflectometry (TDR) and time-domain transmissometry (TDT), have been used to locate faults in twisted cables, telegraph lines, and connectors in the electrical and telecommunication industry. This article provides a brief review of conventional TDR and its application limitations to advanced packages in semiconductor industry. The article introduces electro optical terahertz pulse reflectometry (EOTPR) and discusses how its improvements of using high frequency impulse signal addressed application challenges and quickly made it a well-adopted tool in the industry. The third part of this article introduces a new method which combines impulse signal and the TDT concept, and discusses a combo TDR and TDT method. Cases studies and application notes are shared and discussed for each technique. Application benefits and limitations of these techniques (TDR, EOTPR, and combo TDR/TDT) are summarized and compared.

This article is a brief account of various factors pertinent to the characterization of materials and analysis of optical components, namely transmission, haze, yellowness, refractive index, surface irregularity, birefringence, internal contamination, surface gloss, and color. In addition, details on ad hoc tests used for determining the acceptability of a plastic part for its application are provided, along with typical examples.

The need for precise targeted interactive surgery on boards or modules is the main driver of backside preparation technology. This article assists the analyst in making decisions on backside thinning and polishing requirements. Thinning of the substrates can be accomplished by flat lapping, laser assisted chemical etch, plasma reactive ion etch, and CNC based milling and polishing. The article discusses the general characteristics, key principles, advantages, and disadvantages of these processes. It also contains case studies that illustrate the application of these processes to ceramic cavity devices, injection molded parts, and ball grid arrays.