Testing, assembly and package development are tightly coupled to the circuit design. The test and assembly methods evolve as the design matures. A tightly integrated package and circuit development program is therefore needed. A number of tools are used:
Reference designs
For first laboratory proof-of-concept, it is often cost-effective to use standard templates and off-the-shelf parts. Development programs are driven by product requirement and methods may deviate from standard templates to suit the size, weight, power and costs requirements. PIXAPP.eu provides advice and access.
Pre-testing in software
The simulation tools used in circuit design are now able to include common laboratory test and measurement equipment. Scripting methods are being introduced to simulate circuits in the lab environment. This ensures testable
design before committing to fabrication. The same scripts can be used for simulation before fabrication and measurement afterwards, ensuring that the simulation data can be rendered in precisely the same format as measurement data, accelerating analysis.
Test automation
Dedicated wafer runs contain hundreds of samples, and test methodologies are required which are reproducible and time-efficient.
In-line testing uses process control modules with foundry designed structures in order to assess that the inline parameters are within the generic process specifications on their customers wafers. The foundry can perform wafer level electrical tests on dedicated probe stations, as well as manual and soon automated die level electric and optical tests on other testers. We also have climate chambers for reliability tests.
Die level testing with automated part handling, fiber alignment and electrical probing is in advanced development to allow functional testing without human error. The scripting provides quality control documentation.
Test-as-a-service
The precise tests evolve as the PIC design matures. Smart Testing methodologies leverage combinations of in-line measurements, and off-line functional tests. Remote testing services can provide a faster and more flexible means of evaluating dies and wafers, accelerating the design cycle. In practice, test coverage share between foundry and customer depends on test capabilities of the suppliers and on the needs from the customer.
