THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

The ever increasing requirements for electrical performance of on-chip wiring has driven three major technological advances in recent years. First, copper has replaced Aluminum as the new interconnect metal of choice, forcing also the introduction of damascene processing. Second, alternatives for SiO2 with a lower dielectric constant are being developed and introduced in main stream processing. The many new resulting materials needs to be classified in terms of their materials characteristics, evaluated in terms of their properties, and tested for process compatibility. Third, in an attempt to lower the dielectric constant even more, porosity is being introduced into these new materials. The study of processes such as plasma interactions and swelling in liquid media now becomes critical. Furthermore, pore sealing and the deposition of a thin continuous copper diffusion barrier on a porous dielectric are of prime importance. This review is an attempt to give an overview of the classification, the character...

Low dielectric constant materials for microelectronics

Effects of the substrate on the determination of thin film mechanical properties by nanoindentation

The Advanced LIGO gravitational wave detectors are next generation instruments which will replace the existing initial LIGO detectors. They are currently being constructed and installed. Advanced LIGO strain sensitivity is designed to be about a factor 10 better than initial LIGO over a broad band and usable to 10 Hz, in contrast to 40 Hz for initial LIGO. This is expected to allow for detections and significant astrophysics in most categories of gravitational waves. To achieve this sensitivity, all hardware subsystems are being replaced with improvements. Designs and expected performance are presented for the seismic isolation, suspensions, optics and laser subsystems. Possible enhancements to Advanced LIGO, either to resolve problems that may arise and/or to allow for improved performance, are now being researched. Some of these enhancements are discussed along with some potential technology being considered for detectors beyond Advanced LIGO.

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Advanced LIGO: the next generation of gravitational wave detectors

Characterization of amorphous and nanocrystalline carbon films

The hardness of a number of coated systems has been measured using a variety of experimental techniques ranging from traditional macro-Vickers indentation to ultra-low-load depth-sensing nanoindentation. This has allowed the hardness response to be measured over scales ranging from those less than the coating thickness, where a coating-dominated response is expected, to much more macroscopic scales where system behaviour is dominated by the substrate. The objective has been to construct a mathematical description of the hardness performance of coated systems which well describes the behaviour over this wide range of scales. Previous attempts at such quantitative descriptions have usually involved models focusing on some particular deformation mechanism (e.g. plasticity, elastic response or fracture). In contrast, this paper presents a new approach to analysing hardness data essentially using dimensionless parameters containing descriptors equally applicable to either plasticity- or fracture-dominated behaviour with all scales measured relative to the coating thickness. The model shows an excellent fit to a wide range of experimental data. Furthermore, once the fit has been made, not only can some deductions be made regarding dominant deformation mechanisms, but the model allows predictions of the contact response of other coated systems to be made.

On the hardness of coated systems

The scratch test has been used to assess coating adhesion for some time. In this test, a diamond indenter is drawn across the coated surface under an increasing load (either stepwise or continuous) until at some load, termed the critical load L c , a well-defined failure event occurs; if this failure event represents the loss of coating-substrate adhesion then the critical load can be used as a qualitative measure of coating-substrate adhesion. However, it is well known that a range of possible failure modes can occur and only some of these are dependent on adhesion; other failure modes which depend on plastic deformation and fracture within the coating, rather than any adhesive failure at the coating-substrate interface, may be just as useful in the assessment of coating quality for tribological applications. In this study, titanium nitride coatings have been deposited onto a range of different substrates from soft nickel to a hard cemented carbide and the failure modes which occur during scratch testing have been identified. Failures fall into two general groups, depending on whether the substrate behaves in a brittle or ductile manner during the scratch test. Similar failure modes are observed for titanium nitride coatings produced by several deposition technologies, although there is some variation in the appearance of specific failures which is process dependent. Many of the same failure modes are also observed for other coating materials, such as ZrN or hard carbon, but several different types of failure are also observed. The generation of acoustic emission during the test is related to the occurrence of these different failure modes. The origin of the failure modes and the use of the scratch test to assess coating-substrate adhesion are discussed in the light of these observations.

Failure modes in scratch adhesion testing

https://eprints.ncl.ac.uk/file_store/production/56373/74E3E1A7-8D83-4218-8DA6-EDC480E11A4F.pdf

An overview of the potential of quantitative coating adhesion measurement by scratch testing

Failure mode maps in the thin film scratch adhesion test

A quantitative model is proposed to explain the indentation size effect (ISE) often observed in the hardness response of hard brittle materials, namely that hardness is observed to increase with decreasing indentation size. The model is based on a mixed elastic/plastic materials deformation response whereby plastic deformation occurs in a discrete manner progressively to relieve stresses created by elastic flexure of the surface at the edges of the indentation. During unloading of the indenter, recovery of the elastic increment of deformation, which precedes each new band of plastic deformation, results in the indentation appearing smaller than expected, particularly as the indentation sizes decrease to approach the scale of the plastic deformation band spacing. The model fits observed experimental data well and analysis of hardness/size data in this way is shown to allow both a bulk hardness value and a characteristic deformation band scale to be calculated for a given sample.

Steve Bull

Papers

On the hardness of coated systems

Failure modes in scratch adhesion testing

An overview of the potential of quantitative coating adhesion measurement by scratch testing

Failure mode maps in the thin film scratch adhesion test

An explanation of the indentation size effect in ceramics