Cyanate Ester Substrate Flexural Modulus and Strain Rosette Signal Loss
Cyanate ester flexural stiffness induces adhesive shear lag and interfacial microcracking, causing rosette signal loss and latent solder interconnect escapes.
ICT Fixturing
Mechanical Interface
Pin-plate assemblies containing spring-loaded probes establish electrical contact with test points on a populated printed circuit board. Custom-built ICT fixturing secures the board under test, using vacuum force or mechanical clamps to compress it against the probe field. This arrangement ensures that each test probe exerts the correct mechanical force on its target pad or through-hole lead.
It holds the board in a flat plane to ensure simultaneous contact across all probe points without damaging delicate surface mount components. The physical housing must maintain dimensional stability across thousands of compression cycles to prevent measurement drift caused by misaligned probes.
Board Distortion
High force concentrated on a localized region of a circuit board during contact compression can bend the substrate. The spring probes used in ICT fixturing exert cumulative mechanical pressure that can flex the board if it is not supported by backing pins. This flexure induces board strains that can crack ceramic capacitors or shear ball grid array solder joints during the test cycle.
Correct placement of support pillars directly beneath high-density probe areas minimizes this deflection.
Pin Alignment
Precision guide pins align the board with the probe plate. Standard ICT fixturing utilizes steel pins that fit into dedicated mounting holes. This alignment keeps probe deflection within tolerance, preventing damage to solder masks.