SIMS analysis of small area device samples

As device dimensions decrease and wafer real estate increases in value, it becomes ever more important to conserve the space dedicated to test structures. As devices become more complex, it becomes more vital to provide supporting Secondary Ion Mass Spectrometry (SIMS) measurements. Most SIMS test structures have been designed with a minimum size dimension of 100-μm. It has been very difficult to obtain useful data on structures of smaller dimensions. In some cases appropriate test structures do not exist. We show SIMS results on areas as small as 10-μm on a side, and discuss variations in depth resolution and detection levels that are highly dependent on the instrumental setup, and on the ratio of measured area to device area.