The chemical composition of links in a semiconductor characterization
On the standard scanning transmission electron microscopy (STEM) using 30 mm2The detector areaEnergy dispersive X-ray spectroscopy(EDS or EDX) available in a few minutes with nanoscale resolution element surface analysis.Analysis on condition that, when the probe head is small enough (fine diameter design), the probe can be as close as possible to sample (high solid Angle) and relatively high enough sample (widely).The latter helps to avoid the shadow effect and reduce the absorption of the negative impact of the results.
Standard STEM 30 mm installation2Effective area, with a SLEW of EDS, can achieve 0.09 sr solid Angle of detector and the detection of 22 ° Angle.We use it to analyze the connection in a semiconductor structure (figure 1).Element distribution characterization can be successful.The use of quantitative methods of dealing with Cliff - Lorimer EDS data.Cliff - Lorimer theory in ESPRIT software factor is calculated based on the following information:
- With radiation cross section and the fluorescence strong values, complete atomic database
- The probe and the sample's geometry
- The detector of quantum efficiency
In a series of specimen under the condition of the same study, with the methods of theoretical calculation factor Cliff - Lorimer relative to the selected in the sample series of standard sample, can be accurate to within a few atomic percentage.EDS data clearly shows the Ta and TiN lining interconnection of tantalum and titanium, tungsten and copper and filling (figure 2).Titanium signals can be isolated from nitrogen signal.Can go to work and distribution of Si, Ta and right W (figure 3).
