A novel excimer laser process has been developed for generating cylindrical via holes with an aspect ratio of about one. The fabrication process is being successfully run on a production line for a highly miniaturized printed circuit board used for the multichip module in the new Siemens 7500 H 90 mainframe computer. The process is outstanding in terms of reliability and reproducibility. To the best of our knowledge, this is the first that that excimer lasers have been put into large-scale use in an industrial environment.

Since signal delay times for chips have decreased much more rapidly than delay times for packaging, the computing speed of high-speed computers is restricted by the packaging techniques used. Therefore, further development of packaging technology became a prime objective for those developing high-performance computers. Packaging delay times had to be reduced drastically to keep up with increasingly shorter chip delay times. This, in effect, meant that a greater packaging density had to be implemented.

A novel planar packaging technique has lead to considerable progress in solving this problem. This technique has been described in detail elsewhere. A key component in this technology is a multichip module, which can take in each of 16 areas, either an LSI module with 320 leads or 9 MSI modules with 52 leads as “bare” ICs. This means that a micro-wiring printed circuit board of this kind can accomodate between 16 (LSI) and 144 (MSI) chips. This article describes how these printed circuit boards are manufactured.

As the specifications (Table I) show, blind vias 80 μm in diameter at a pitch of 0.5 mm have to be made in a 16-layer printed circuit board. It is intended that these blind vias will provide the through-contact for neighboring layers. The excimer laser plays a major role in this process.

Most great technological advances initially required finding a solution to materials problems, a fact that is not very often recognized. The development of nuclear energy is no exception to this rule. The fuel in the reactor core, cladding of the fuel, and structures which support the core or which carry the coolant are, indeed, subjected to extreme conditions of radiation flux, temperature, pressure, and corrosion. In order to achieve safe, industrial reactors, the French Atomic Energy Commission (CEA) had to build an enormous program in materials research and development from the ground floor. At present, CEA has reached a very high level of knowledge and expertise through excellent scientific teams and exceptional equipment.

In its present industrial phase, the French Nuclear Program still requires considerable effort in research, but it does enable the nation's industry to take advantage of the CEA's materials capabilities. In accordance with its mission to facilitate the utilization of research results, the CEA launched research and development programs in different non-nuclear industries where its research could find new applications.

Since its creation in 1955, the Grenoble Nuclear Research Center (CEN-G), one of the five civilian centers of the CEA, has concentrated a great part of its research on basic (solid-state physics) and applied aspects (nuclear metallurgy). This double orientation, in which basic research is used as a basis for applied research, is an original feature of the CEN-G.

Archaeologists have used microscopes to study traces of use on the edges of prehistoric stone tools for many years, but the past decade has seen a tremendous increase in the technical sophistication and substantive contributions made by this branch of archaeological research. Our purpose is to summarize the basic approaches archaeologists take to microwear analysis, the potentials of these approaches, and the kinds of traces that microwear analysts examine.

Three forms of microwear analysis can be identified and are based on (1) the range of magnification, (2) the type of equipment, and (3) the type of traces examined. The first relies on stereoscopic microscopes, works at magnifications ranging from 10 to 75×, and examines patterns in the abrasion and chipping of tool edges during use. More recent research indicate s that important variation also exists in the way a tool surface is polished during use, and the second analytical approach examines differences in polish appearance as well as utilizing the techniques of the first method. Microwear polishes are visible at magnifications from 100× to 400× using binocular microscopes and incident illumination. Finally, the third approach relies on the scanning electron microscope (SEM) and very high magnifications to identify traces of materials on which the stone tools were used. In this discussion we emphasize the first two of these analytical approaches because very few analysts have used the SEM.

The Von Hippel Award, the most prestigious award of the Materials Research Society was first presented to its namesake, Arthur von Hippel, in 1976. On November 19, 1988, Prof. von Hippel celebrated his 90th birthday, an appropriate occasion to look back on a lifetime of achievement. Through the many testimonials that were heard at his 90th birthday celebration from family, friends, former students and colleagues, emerged a picture of materials science that reflects much that we treasure as the fabric of the Materials Research Society, namely the interdisciplinary approach to materials research.

It has become an annual tradition of MRS to celebrate the achievement of the Von Hippel Award winner, and each year the celebrants begin the ceremony with an affirmation of the efficacy of the interdisciplinary approach. In the early years of the Von Hippel Award, our young students often heard greetings from Prof. von Hippel himself during the opening ceremony. But as the size of the meetings has grown, it has become increasingly difficult for “The Professor” to offer personal greetings. Many young people today yearn for contact with their intellectual heritage. Inspired by this need, the leadership of MRS recommended that a brief article be written for the MRS BULLETIN on reminiscences about Prof. Arthur von Hippel and his legacy of the interdisciplinary approach to materials research.