Now available in Minitab Graph Builder.
When every chip counts, understanding where and why defects occur is critical to protecting yield. In semiconductor manufacturing, even the smallest irregularities can turn into significant financial losses. Since hundreds of chips are fabricated on a single wafer, small process deviations can result in millions of dollars lost to scrap, rework, or reduced output.
Modern fabrication facilities generate mountains of data, but without spatial context, defect patterns can go unnoticed. Looking at metrics like lot level yield with only summary statistics often assumes that defects are randomly distributed across the wafer. In reality, that assumption rarely holds true. Defects frequently follow spatial patterns such as rings, clusters, checkerboards, or stripes that can reveal deeper, systemic issues in the manufacturing process.
Introducing the Wafer Plot: A Clearer View of Manufacturing Quality
Summary statistics tell you what happened, but wafer plots help you understand why. To help engineers uncover these hidden patterns, Minitab’s Graph Builder now includes a powerful new visualization: the Wafer Plot. This tool maps chip-level defect data directly onto a wafer layout, allowing engineers to see exactly where defects occur. Each chip is plotted by its physical coordinates, and defects are color-coded to indicate severity or frequency. This spatial context transforms raw data into action.
Let's look at an example. The wafer plots below display defect distributions across five different lots. Notice the red ring forming near the edge of the wafer in Lot 5? What appears to be a simple visual pattern is in fact a ring-shaped defect, often an indicator of uneven temperature distribution during the rapid thermal annealing process. Without this visualization, you might have seen a dip in yield and been left guessing. With the Wafer Plot, the problem practically draws itself.
From Visualization to Root Cause
Another compelling example of the Wafer Plot’s diagnostic power comes from the visualization seen in Lot 1, shown below. At first glance, the plot reveals a non-uniform distribution of defects, with lighter regions indicating higher defect density. This concentration is not random and could suggest a systematic issue in the process. Imagine you're a yield engineer reviewing this plot after a routine test. You notice this pattern and realize it could point to a localized contamination event, perhaps dust particles near the edge of a machine or a misaligned tool during a production step. Without the simplicity of the Wafer Plot in Graph Builder, this issue might have been buried in the numbers. But with visualization, the root cause becomes visible, allowing for targeted investigation and corrective action before the problem spreads to additional lots.
The Wafer Plot is more than just a visual aid. It’s a diagnostic tool that supports:
In semiconductor manufacturing, every chip matters. And with the Wafer Plot, engineers now have a sharper eye to detect, diagnose, and defeat defects before they spiral into costly problems. Whether you're troubleshooting a single lot or monitoring trends across an entire fabrication facility, this tool helps you move from reactive to proactive process control. Because when it comes to yield, you can’t afford to miss the patterns hiding in plain sight.
Try the Wafer Plot in the Minitab Solution Center today!