Manufacturing processes for semiconductor devices include procedures which require minute nano-level machining. This means that extreme caution must be exercised to ensure that there is no inclusion of particles or other solid foreign matter, and no dissolution of impurities in any chemical solutions or water which comes into contact with semiconductor devices.
Therefore, Ebara carries out thorough quality control for all components used in semiconductor manufacturing equipment, particularly components that come into contact with devices directly, and components exposed to chemicals that come into contact with devices.
Here, we will introduce our dissolution tests, which are conducted separately from our measures for quality control pertaining to dust generation from components.
As an example of these tests, when new components are to be adopted as wafer cleaning components in place of previous ones, comparisons of their dissolution content are conducted.
Specifically, the target components are immersed in ultra-pure water or chemical solutions under specified conditions, and the content dissolved from the new components, particularly metallic material and other content whose inclusion should be avoided in the manufacture of semiconductor devices, is confirmed to be at or below a certain concentration.
Since the concentration required for detection here is at the ppt* level, an inductively coupled plasma mass spectrometer (ICP-MS), which can analyze multiple types of elements all at once with extremely high sensitivity, is used for analysis.
This level of analysis also requires contamination from the environment to be eliminated to the absolute greatest extent possible, so analysis processes undergo rigorous management which includes performing all operations in clean rooms and cleaning all containers used for long periods of time with ultra-pure water.
Only components which pass these evaluations are then accepted for use.
Wafer cleaning component
ICP-MS
*ppt:
Concentration which is one-millionth of a ppm. 1 ppt is equivalent to an amount of 1 μg dissolved in 1000 L of water.