Microelectronics analytical problems

In the following pages we first give brief accounts of the developments in microelectronics, computers and data processing which underpin virtually all modem analytical methods. Secondly some novel methods, which indicate the breadth of the subject and the trends towards high sample throughput and/or complexity of analysis will be described. Finally a major specific analytical problem, re-presenative of many likely to be encountered in the foreseeable future will be discussed. In the space available, selectivity and brevity is essential. Our object is to indicate trends, not to be comprehensive. 

Application of the Raman Microprobe to Analytical Problems of Microelectronics... 

Before describing the surface analysis of the materials listed above, the advantages and limitations of the surface-specific techniques to be used should be discussed. The basic principles, instrumentation and main applications of photoemission (1-3] and Auger [4,51. spectroscopies, as well as of SAM [6.7] and ELS [8-11] have already been described in several reviews, while Seah and Briggs [12] have surveyed in detail the principal features of many suri ace-specific techniques. Of major interest here are those characteristics of each technique that, on the one hand, may be employed strategically to solve a given analytical problem, but that on the other may affect the reliability of the results. In Table 1 the relative merits of the techniques are rated with respect to those properties likely to be important in the surface analy.sis of semiconductors and microelectronic devices. 

Chemically modified electrodes (CMEs) represent a modern approach to electrode systems. These electrodes rely on the placement of a reagent onto the surface, to impart the behavior of that reagent to the modified surface. Such deliberate alteration of electrode surfaces can thus meet the needs of many electroanalytical problems, and may form the basis for new analytical applications and different sensing devices. Such surface functionalization of electrodes with molecular reagents has other applications, including energy conversion, electrochemical synthesis, and microelectronic devices. 

A Students entering the field of analytical chemistry need to be open minded. If you are a well-trained analytical chemist, you must not be afraid of touching other fields to solve your problem. There are no boundaries Advances in analytical chemistry will be the result of bringing in techniques from other fields material science, nanotechnology, microfabrication, microelectronics and, of course, proteomics and genomics. Students need to learn to talk to people in other disciplines. 

The problem-solving mode offers great advantages In developing and maintaining the high level of process control required In the microelectronic Industry today (and tomorrow). The analytical/ characterization group can quickly show Chat It Is a vital part of the entire series of process steps from research and... 

Practising analytical chemists face both qualitative and quantitative problems. As an example of the former, the presence of boron in distilled water is very damaging in the manufacture of microelectronic components - Does this distilled water sample contain any boron . Again, the comparison of soil samples is a common problem in forensic science - Could these two soil samples have come from the same site . In other cases the problems posed are quantitative. How much albumin is there in this sampie of biood serum , How much lead in this sample of tap-water , This steei sampie contains smaii quantities of chromium, tungsten and manganese - how much of each these are typicai exampies of single-component or multiple-component quantitative anaiyses. 

These problems might be resolved by the ion-selective field-effect transistor (ISFET). In an IS-FET the ion-selective membrane is placed directly on the gate insulator of the field-effect transistor alternatively, the gate insulator itself, acting as a pH-selective membrane, may be exposed to the analyte solution (Fig. 28). If one compares an ISFET with the conventional ISE measurement system, the gate metal, connecting leads, and internal reference system have all been eliminated. An ISFET is a small, physically robust, fast potentio-metric sensor, and it can be produced by microelectronic methods, with the future prospect of low-cost bulk production. More than one sensor can be placed within an area of a few square millimeters. The first ISFETs were described independently by Bergveld [142] and Matsuo, Esashi,... 

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