ZhenAn, What Are The Basic Methods Commonly Used For Target Material Grain Testing?

ZhenAn, what are the basic methods commonly used for target material grain testing?

Target materials are typically polycrystalline, with grain sizes ranging from microns to millimeters. The finer the grains, the larger the grain boundary area, and the greater the impact on performance. For the same target material, targets with fine grains have a faster sputtering rate than targets with coarse grains. Targets with smaller grain size variations (uniform distribution) produce more uniform thickness distributions in sputtered films. Research has found that if the grain size of a titanium target is controlled below 100 μm, and the variation in grain size is kept within 20%, the quality of the resulting sputtered film can be improved. Significant improvement.

Three basic methods for target grain size testing
1. Comparison method: The comparison method does not require counting grains or intercepts. When comparing with a standard series of rating charts, grain size assessment using the comparison method generally exhibits a certain degree of deviation (±0.5 levels). The reproducibility and reproducibility of the assessed values ​​are typically ±1 level.

2. Area method: The area method counts the number of grains within a known area and uses the number of grains per unit area to determine the grain size grade. The accuracy of this method is a function of the calculated grain size, and with proper counting, an accuracy of ±0.25 levels can be achieved. The results of the area method are unbiased, with a reproducibility of less than ±0.5 levels. The key to determining grain size using the area method lies in counting grains that clearly demarcate the grain boundaries.

3. Intercept method: The intercept count is calculated by counting the number of intercepts where a test line segment (or grid) of known length intersects the grain boundaries. The grain size grade is determined using the number of intercepts per unit length. The accuracy of the intercept method is a function of the number of intercepts or intercepts calculated, and can be achieved through effective statistical analysis. ±0.25 level accuracy. The intercept method measurement results are bias-free, and the reproducibility and reproducibility are less than ±0.5 level. For the same level of accuracy, the intercept method does not require accurate marking of intercept points or intercept numbers, so it is faster than the area method.