Shear Deformation Kinetics of Inner Layer Heavy Copper Features during Vacuum Pressing
Shear forces during vacuum pressing shift heavy copper traces when resin flow velocity exceeds interfacial bond strength, requiring optimized aspect ratios.
370HR
Substrate Characterization
Rigid substrate materials specified for multilayer board fabrication establish electrical isolation and structural integrity under thermal loads. The proprietary glass-reinforced epoxy laminate designated as 370HR provides thermal reliability through a glass transition temperature of 180 degrees Celsius. Its cross-linked polymer network limits z-axis thermal expansion during lead-free soldering operations, reducing stress on plated through-hole structures.
Thermal Stability
Mechanical endurance during sequential reflow processes relies on low out-of-plane thermal expansion values. When temperature levels exceed the glass transition point, standard laminates expand rapidly along the vertical axis, cracking internal copper barrels or shearing microvia interfaces. Substrates fabricated with 370HR maintain dimensional stability across multiple assembly cycles up to 260 degrees Celsius.
The material resists thermal decomposition up to 340 degrees Celsius, preserving dielectric performance across high-density interconnect layers. High-volume manufacturing plants utilize this material specification to lower rejection rates caused by inner-layer delamination.
Lamination Behavior
Production parameters during multi-platen pressing require controlled temperature ramp rates to ensure full resin cure. Resin flow behavior during the melt phase fills fine-line copper features without creating entrapped air pockets. Laminate thickness tolerances remain tightly controlled across large panel formats, preventing impedance variations along long signal traces.
High resin content options allow complete encapsulation of heavy copper planes. Process engineers specify exact curing dwell times to maintain consistent dielectric constants throughout the board stackup.