JMP platforms and statistical methods

Graph Builder:
Comparative dot plots, line graph

Objective

Use data visualization methods and summary statistics to analyze data from an experiment with operators using a semiconductor measurement tool to evaluate potential causes of inaccurate measurements.

Problem statement

Electrical resistance is a critical performance metric that is used to evaluate the quality of semiconductor wafers used in chip manufacturing. A common device used to measure this characteristic is a four-point probe. To measure sheet resistance, four electrodes are placed onto the surface of the wafer. Electric potential is applied to two of the electrodes, and the electric current flowing through to the other two is measured.

Engineers in one of the labs that uses this measurement device are concerned that there may be factors that could result in inaccurate measurements. The main concern they have is that residual material may build up on the probes resulting in an incorrect reading on subsequent film that is measured. It is of particular concern when the films are of different materials. A step that can be taken is to condition (i.e., clean) the probes prior to each use. Since it adds time to the measurement process, it is only done periodically in practice.

Another consideration they have is that perhaps different operators of the device may not be following the exact same measurement protocol and are producing different results, specifically an experienced user vs. a new user.