General requirements that should be adhered to include but not limited to the following:
- Minimum pitch requirements, center to center should be set at 0.015
- Pad Length – minimum 0.070
- Grid Location - Each test point in a given area should have accessibility to a specific / unique grid location within 0.200
- 100% test requires test points do not exceed the number of grid points.
In the first figure below, test points are identified by the nomenclature. Also, surrounding via pads are to be covered with resist. Test points are clearly defined solely for the purpose of testing and probing. The second figure below shows typical vias that have been left exposed, free of resist allowing access for probing if required.