We believe that every tool we write should make the work of the engineer more efficient and allow the engineer to focus on the real problems and not on the drudge of preparing complex reports from awkward formats such as STDF and various other less popular text and binary formats. Drift analysis is another important capability for Test Engineers where we can make a difference. This tool is for beta release in yieldHUB in the next few weeks.
When you collect data at each step of burn-in or life test, you need to see how key tests drifted.
The ‘population’ drift is as important as the drift of any individual die. After collecting the data, you don’t want to have to take more than a few minutes setting up the analysis before you see the results. Also you will want to have very clear visualizations and tables so you can present any findings quickly and clearly to your colleagues and management.
Often it’s important to visualize and analyze the drift as follows:
- % drift Vs the original value for each die
- % drift Vs the limit width
- The actual drift for each die
- The actual value for each die at each burn-in step
- The mean drift at each burn-in step
These will be achievable in yieldHUB soon with our new tool with little preparation. Practical considerations are critical. For example we won’t assume that the same test programs are run at each step, although that is the most likely scenario. Hence we will allow you to match a test across different programs. If the program is the same, the test is automatically linked across the steps.To match the dice themselves, you will be able to tell yieldHUB to use the serial number associated with each unit or the x/y location for wafers.
Fig 1 Actual values at each step of Burn-in
Fig 2: Drift from time zero
Other visualizations are also included and others are being added based on feedback from our lead customers for this tool. An example is a histogram of drifts grouped by burn-in step for any parameter.
So if you don’t want to end up burnt out by burn-in, talk to yieldHUB about our great new drift analysis tool!!