Selected “Best Overall Presentation” at SW Test 2016
Abstract:
Over the last year, TI has seen an influx of devices requiring the probing of Cu pillar devices. There are different flavors of these types of devices, some with a bare Cu top and some that have Cu capped with solder.
Historically, cantilever has been the baseline technology for probing these devices. However, as the geometries get smaller and requirements get more stringent, there is more the need to move towards a more robust solution. Therefore, vertical probe card technology has been evaluated to help replace some of the shortcomings of cantilever.
TP6xxx and LP8xxx were identified as test vehicles for probing on Cu pillar with vertical probe technology. Technoprobe was selected as the vertical vendor to take the existing TP6xxx and LP8xxx platforms (PCB, and HW) and only replace the Cantilever head with a vertical probe head.
– The TP6xxx device has one insertion at room temperature.
– The LP8xxx device has two insertions at room temperature and a 24hr bake at 125oC for data retention.
In developing the Technoprobe M3 vertical solution on Cu pillar, there were a couple issues that had to be addressed:
– Continuity failures
• Different tip shapes on the Cu pillar surface
• Pins were sliding on the bare Cu Pillar
• The Tip was changed to a flat 40x55um tip w/ hard material
– Cleaning Setting Optimization
• Optimize the probing and cleaning
The key factors for Cu Pillar probe card technology were found to be tip shape, cleaning settings, and overtravel.
In summary, cantilever has long been baseline for probe technologies on Cu pillar probing applications in TI, but as new rigorous requirements for TI’s devices required a more robust solution for Cu pillar probing, the future is in vertical technology. Initial challenges had to be overcome in terms of contact failures and cleaning settings, but after resolving these issues, the Technoprobe M3 probes provided good results on probing the Cu pillars.