Resistive-buildup contaminants from solder, Online cleaning materials – Cascade Microtech P800-S User Manual
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Pyramid Probe Card: P800-S Online Cleaning• 2
Resistive-Buildup Contaminants From Solder
Resistive buildup contaminants such as organics and oxides can accumulate on the probe tips during probing (see
). To maintain high yield, these contaminants must be removed by abrasive cleaning. For best results, this
contamination should be removed preventively. Resistive buildup contaminants do not usually damage probe tips directly.
However, in response to the increasing contact resistance caused by this buildup, users may choose to increase overtravel
— which stresses the probe tips and can cause premature probe failure.
Probe tips for solder-ball probing are much more susceptible to accumulation of resistive-buildup contaminants. Under
normal probing, the soft solder material sticks to the probe tip surface. This buildup typically appears as a dark-colored
mass that covers the entire tip surface and occurs with all types of solder alloys. Often, the mass will include areas that are
green, blue, brown, or black. Yield will suffer if this buildup is not removed preemptively with aggressive online cleaning.
Online Cleaning Materials
The most effective method for controlling contact resistance (Rc) and cleaning resistive buildup from Pyramid Probe tips is
online cleaning by touching down on an abrasive. Abrasive cleaning media can be divided into four categories:
• Abrasive coated foams
• Abrasive loaded elastomers
• Lapping films
• Soft-backed lapping films
The only recommended media for cleaning the P800-S is an abrasive coated foam.
The results of a cleaning study performed at Cascade Microtech were presented at the at the 18th Annual IEEE
Semiconductor Wafer Test Workshop in June 2008 in a paper by Eric Hill and Josh Smith, Probe Card Cleaning Media
Survey. The presentation can be viewed at
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Excessive use of abrasive substrates may cause premature failure of Pyramid Probes.
Figure 3. Solder buildup.
Figure 2. Clean probe tip.
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Online Cleaning Instructions