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Wafer Probe Bin Yield Log Worksheet

Wafer sort produces a bin map for every wafer, and yield engineers constantly summarize those maps into lot and product trends. This worksheet turns bin counts into sort yield and loss shares you can export to Excel.

Download:
LotWafer #Gross dieBin 1 passBin 2 parametric failBin 3 functional failBin 4 contact/open-shortDie testedSort yieldFunctional fail lossUntested die
606
89.3%
5.1%
6
608
91%
4.4%
4
612
81.4%
8.5%
0
612
82.8%
8%
0
612
91.5%
3.9%
0
612
92.5%
3.6%
0
Total gross die
3,672
Total good die
3,225
Total die tested
3,662
Average wafer sort yield
88.1%
Worst wafer yield
81.4%
Pooled sort yield
88.1%
Total good die divided by total die tested across all wafers.
Parametric fail share
4.1%
Functional fail share
5.6%
Contact fail share
2.3%

Bin numbers differ by product and test program. Rename the columns to match your own bin table, and keep a bin 4 style contact or open-short bucket separate from device failures, since high contact failures usually point to probe card or test setup problems rather than fabrication.

Link sort yield to lot cost in your ERP

Optional: discuss combining test data with ERP lot costing, privately.

Optional. The tool and every export work without this. No spam.

How to use the worksheet

Add one row per wafer. Enter the gross die count from the wafer map and the number of die in each bin from the probe summary or datalog. Tested die, sort yield, functional fail loss and untested die are calculated automatically. The summary shows pooled yield across all rows and the share lost to each fail bin. Rename the bin columns to match your test program, delete the example rows, and export to Excel or CSV. Use the same layout for every lot so trend charts line up.

  • One row per wafer
  • Match bin names to your bin table
  • Check untested die is near zero
  • Export to CSV for trend charts

Sort yield formula

Sort yield is good die divided by die tested, shown as a percentage. Some teams divide by gross die instead, which hides test coverage problems. This worksheet uses tested die in the denominator and shows untested die separately so that missing die are visible. Pooled yield adds counts across wafers before dividing, which is more accurate than averaging per-wafer percentages when wafers have different tested counts. The sheet shows both so you can see the difference.

Reading the loss buckets

Each bin tells a different story. A rise in contact failures often follows a probe card change, worn needles or contamination on the pads. Parametric failures such as leakage or threshold voltage shifts trace to process drift and are often clustered on specific wafers. Functional failures can be random, caused by defects, or systematic, caused by a layer problem. Compare edge versus center on the bin map, and compare wafers within a lot. One bad wafer in a lot usually points to a single-wafer process such as a chamber step.

Common mistakes

Do not mix retests and first-pass results in the same row without labeling them. Counting reprobe passes as first-pass inflates yield and hides contact problems. Keep the gross die count consistent with the product's reticle map, including partial edge die rules. Watch for mixed products in the same lot log. Finally, avoid comparing yield across test programs without confirming that the limits and bin definitions are the same.

Frequently Asked Questions

Is sort yield the same as final test yield?

No. Sort yield is measured at wafer probe on whole wafers. Final test yield is measured after packaging on individual units. Overall yield through the flow combines wafer sort, assembly and final test losses.

Should I divide by gross die or tested die?

Using tested die is common for sort yield, because it measures how many of the die actually tested were good. Track untested die separately so that missing data does not disappear from view.

How do I add more bins?

Add a column in your Excel export and extend the tested formula. Inside the tool, rename the four existing bin columns to the groups you track most, such as leakage, speed and memory test.

Can this be used for final test lots?

Yes. Replace wafer number with tray, reel or strip number and gross die with units tested. The bin and yield logic works the same way.

If your sort data lives in test databases and your ERP holds lot and cost data, Netray can help you query both in plain language on your own servers.

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