The wafer level reliability (WLR) laboratory performs accelerated reliability tests of semiconductor devices as part of the technological qualification of a product. Furthermore, the laboratory performs periodical tests as monitor of the production line to reduce the probability that deviant material arrives to the final customer.
There are three main portions of the technology process that are evaluated by WLR tests:
* Device reliability is assessed by Hot Carrier Injection (HCI) and Bias Temperature Instability (BTI) tests
* Gate Oxide Integrity is assessed by Time Dependent Dielectric Breakdown (TDDB) and Voltage ramp (V-ramp) tests
* Metal Interconnects are assessed by Electromigration (EM), Stress Migration (SM), and Inter Layer Dielectric (ILD) TDDB
The execution of accelerated reliability testing requires a large amount of electrical measurements to monitor over time the characteristics of the various devices under stress. For this purpose are used machines and tools (Prober and Testers) that allows to perform electrical measurements automatically.
The objective of the thesis is to develop an automation system that allows the execution of a reliability test by a manufactory operator. The only information that the operator should input to the automation is the LotID, ie the identifier of the batch of silicon wafers to be tested. Then the system shall be able to query different databases in order to find all the necessary information to run the test sending the appropriate commands to the prober and the tester.
Following are the main points of the system to be developed:
* Graphic User Interface (GUI)
o Develop of user interface
o Query to Fab Tracking System
o Query to Equipment Tracking System
o Query to Generic Recipe Manager system
* Prober control
o Develop of a prober control for Accretech A-PM-90A automatic prober
* Loading of the Device Program
* Chuck temperature setup
* Load/Unload of wafer’s cassette
* Load/Unload wafer
* WaferID reading