Probe - Keysight

Increase Test Coverage
Higher Density – Large Boards
Copyright © 2011, Circuit Check, Inc.
What's Involved?
Control – UUT has an ICT friendly design
– Increase your odds in the
manufacturing process
• Don't fight the board
– Let the board select the fixture
2
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
Design ICT Friendly UUT
• Even distribution of test pads
• Tooling holes P0.125 on a diagonal, non plated
• Filled/Plugged vias: Plan on probing only
Type VII Filled and Capped vias
• Agilent Bead Probes avoid manufacturing issues and
place at 0.075" centers
• Probing gold-plated fingers may cause blemishes from probes
– Check company quality acceptance practices
– Add test point location
• Test pads located 0.0625 away from edge of board, and or 0.125 away
from edge of rails.
• Test pad minimum spacing from component edge to test pad center
0.018" plus half solder pad width per IPC-9850 placement guideline.
3
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
Test Pad Location to Component
Half the solder
pad width plus ►
probe clearance
equals total test pad
clearance required.
Half the solder
pad width plus ►
probe clearance
equals total test pad
clearance required.
4
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
X75
X50
X39
X31
.038
.0312
.0264
.024
X75
X50
X39
X31
.080
.073
.0684
.0654
X75
X50
X39
X31
X75
X50
X39
X31
Copyright© 2011 Circuit Check, Inc.
.080
.073
.0684
.0654
.110
.103
.0984
.0954
Probe Spacing Choices
Are here to stay!
X-Probe Technology
.100 - .075
Spacing
Standard Technology
.039
.050
.075
.100
Spacing Spacing Spacing Spacing
100 mil
probe
Probe
Probe Plate
Spacer Plate
Termination Plate
Termination
5
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
.050
.039
.030
Spacing Spacing Spacing
75 mil
probe
50 mil
probe
39 mil
probe
Test Pad MINIMUM Spacing
Relative to Each other
Minimum Recommended Probe / Receptacle Spacing
100-Mil Probe
100-Mil Probe
75-Mil Probe
50-Mil Probe
75-Mil Probe
50-Mil Probe
.068”
.048”
.039”
31-Mil Probe
6
Copyright © 2011, Circuit Check, Inc.
31-Mil X-Probe
.085”
39-Mil Probe
Smaller Targets
39-Mil Probe
.030"
Copyright© 2011 Circuit Check, Inc.
Increase Your Odds
PCB Manufacturing
• Solder mask clearance from edge of pad P .2mm
• Filled/Plugged vias: Plan on probing only IPC 4761
Type VII Filled and Capped vias
• Copper plated vias and pads can be more difficult
due to oxidation and OSP
– other plating options to consider:
• ENIG,
• Immersion Ag or Sn,
• SAC (SnAgCu)
• Keep lead lengths to 0.050" for 100 – 75 mil probes
– Probing leads with < 75mil probes is not recommended
• Agilent Bead probes – correct stencil aperture and orientation
7
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
The Board Selects…
UUT Characteristics selects the fixture
•
•
•
•
•
•
•
•
Smallest test pad size
Probe spacing
Probe count
Board size
Test points both sides
Test access through connectors
Switching power supplies & regulators
Thermal loading during test
8
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
Vacuum
0.18"/.016"
0.030"
9,100
19.5 x 21.0
Both
3 sides
Yes
No
No
y 18 watts @ 90°c
9
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
vs.
•
•
•
•
•
•
•
•
•
•
Pneumatic
Smallest test pad size
Probe spacing
Probe count
Max UUT size
Single or dual sided
Side access
Bi-Level
Tri-Level
Quad-Level
Component Cooling
Copyright© 2011 Circuit Check, Inc.
0.16"/.016"
0.025"
20,000
28 x 39.5
Both
4 sides
Yes
Yes
Yes
y 35 watts @ 90°c
Smaller Test pads w/Guided Probe
0.016" Test Pad
rds
0.035 Test Pad
Probe contacting inner 2/3
of test pad.
Probe contacting edge
of test pad.
Top plate "funnel" drilled slightly
larger than probe shaft.
Probe/Socket tilted in mounting
hole, UUT pushed to maximum
tolerance extreme.
Probe/Socket tilted in
mounting hole, UUT
pushed to maximum
tolerance extreme.
Receptacle mounting and fit
are less of a concern when
probes are guided
.
10
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
Guide Plate Options
“Guide Plate"
added for Top
Side probing
11
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
"Quick Plate "
is cut out of
the Top Plate
®
Copyright© 2011 Circuit Check, Inc.
Stretching the 307x Boundaries
• Not enough probable area on the
large 307x fixture?
• Long wire kit not really an option?
• Custom solutions to expensive or turn time
too long?
12
Copyright © 2011, Circuit Check, Inc.
Extended Probing Kit limits
Large usable area:
19.5" front to back
21.032" left to right
Mandatory keep out
areas for pull down
Towers.
Transfer probe area if
required may reduce
available UUT size if
Movement to side is
not possible.
Vacuum port locations
will change to
accommodate
the UUT positioning
Copyright © 2011, Circuit Check, Inc.
Extended Probe Field
Normal .250 stroke
probes in the 307x rail
area and beyond.
Copyright © 2011, Circuit Check, Inc.
Oversize Wireless Options
Near Standard Design Vacuum or Pneumatic
• Maximum Size UUT without increased T-Board Cost
– Maximum probe-able UUT size 19.5" front to back and 21"
left to right.
• Transfer pins from top access and side access units may
affect maximum size.
• Keep out areas associated with tester's pull downs
Custom Wireless Design Pneumatic only
• Maximum UUT size without keep out areas
– When money is not a consideration 28.0" x 39.5"
• Lead time based on complexity
Copyright © 2011, Circuit Check, Inc.
Summary
• PCB - design optimized for ICT test.
• Manufacturing - considerations to increase first
pass yield and reduce NDFs.
• Increase Test Coverage:
– Decreased probe spacing 0.8 & 1.0mm
– Smaller test targets
• UUT - matched to fixture capabilities
• Extended probing up to 19.5" x 21.0"
16
Smaller Targets
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.
Questions?
17
Copyright © 2011, Circuit Check, Inc.
Copyright© 2011 Circuit Check, Inc.