Methods for rapid and accurate analysis of coating composition and thickness are of major importance for the semiconductor industry. Typical coating problems are Al, Au or Pt coatings on metal and Cr/Ni alloy or SiO2/P2O5 glass on Si wafers. Due to the nature of the coatings ana tne variety of elements, a software package, COAT95 has been developed to cover the following three possible situations:

• 1. Single element coating for thickness only.

• 2. Compound, elements A and B, coating on substrate element S, for composition and thickness.

• 3. Compound, elements A and S, coating on substrate element S , for composition and thickness.

The main goal of the COAT95 software is to have all possible models for the single layer coating problems of the semiconductor industry.

For X-ray fluorescence determination of light elements, vacuum X-rays spectrometers are usually used to increase the transmission of the optical path for the soft X-radiation. A vacuum of about 50μHg is required for the determination of elements with atomic numbers down to 9(F).

A vacuum system however, complicates the sample presentation mechanism of a spectrometer; it requires vacuum seals, additional fastening of the flow detector window and, as a results, increases the price of the spectrometer.

In regional reconnaisance geochemical prospecting, it is desirable to determine as many elements as possible, in order to provide a comprehensive cover for the detection of most types of ore mineralization. Multi-element simultaneous instruments are ideally suited to this task, but the maximum number of wavelength dispersive channels (monochromators) which may be fitted to any one of the commercially available X-ray spectrometers is approximately thirty. Because some of these channels are required for the measurement of background, the practical limit for spectral lines is about twenty-five. Additional elements may be determined by inclusion of a scanning channel, but its sequential operation increases the analysis time per sample.

X-ray spectrometry has been used successfully for major and trace element analysis of geological samples (e.g. reference 1). Its advantage is providing accurate and precise results in a rapid manner: a key factor in selecting analytical methods for mineralogical studies involving large numbers of samples. All elements with atomic numbers greater than 9 (fluorine), except noble gases, can be determined with sensitivities ranging down to ppm levels.

The analytical method described in this report is for the determination of the major elements (i.e. Na, Mg, Al, Si, P, K, Ca, Ti, Mn and Fe) in geological samples. Commercially available automated fusion devices are used for sample preparation.

Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability or stability of ground and pelletized coal samples is poor resulting in deterioration with time. As a result, artificial coal standards were prepared from certified geological materials by fusing in lithium-tetra-borate in percentages approximating expected ash contents and compositions in coal. Since the lithium-tetra-borate comprises about the same percentage of the standard as does the carbon, hydrogen, and oxygen in coal, the ground and pelletized coal sample can be assayed against the fused calibration curves by compensating for the differences in the mass absorption coefficients of the two matrices.