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Multi-Layer Mixed Dielectric PCB for Aerospace/Defense

Consisting of multiple laminates and differing dielectric constants, this multi-layer PCB is a mixed-dielectric printed circuit board, which was manufactured for the aerospace industry. Beginning with inventory, all the correct materials were pulled and checked against customer requirements and specifications.

Initially, all inner layers were drilled, imaged, and etched. The inner layers then proceeded to lamination, where they were pressed into panels using low Dk bonding films. After lamination and cool-down, the panels moved to drilling, where all primary holes were drilled. To prepare the hole walls for direct metallization, the panels were processed through plasma and sodium etching.

After DMS, the outer layers of the panels were imaged, copper plated, solder plated and etched. Trace widths had to be controlled to +/- 0.0005″ to provide the end product with proper electrical characteristics. A Liquid Photoimageable (LPI) soldermask was applied, followed by an ENIG (Electroless Nickel Immersion Gold) final finish.

Using several product evaluation techniques, including flying probe testing, we ensured that this PCB met all client product requirements. By the end of this project, our company manufactured 75 multi-layer, mixed- dielectric printed circuit boards for this aerospace customer, vacuum-packaging and shipped all completed items to their facility in the Northeastern U.S.

Multi-layer Mixed Dielectric PCB Highlights

Product Description This multi-layer mixed dielectric PCB is used within an Aerospace application and contains different laminates and structures.
Capabilities Applied/Processes Shearing
Inner layer Fabrication (Image, Etch, and Oxide)
Multilayer Lamination
CNC Drilling
Deburring
Prep Hole Wall
  • Plasma Etching
  • Sodium Etching
Direct Metallization
  • Conductive Polymer
Photolithography 		Plating
  • Copper
  • Tin / Lead Plating
Etching
LPI Soldermask / Silkscreen
ENIG Plate
  • Electroless Nickel- Immersion Gold
Final Fabrication
Packaging
  • Vacuum packed
Equipment Used Alternative Oxide Line
CNC Driller
CNC Router
ENIG Line
Etcher 		Exposure, Developer
Flying Probe Electrical Test
Plasma Etch / Sodium Etch
Vacuum Lamination Press.
Overall Part Dimensions Layers: 6
Length: 3"
Width: 1.5"
Tightest Tolerances ±0.0005" on Etched Features
Material Used Ceramic-filled PTFE, Multi-functional FR4
Material Finish Electroless Nickel - Immersion Gold
Estimated Part Weight 20 Grams
In process testing performed Cross Section Analysis
Full Electrical Test
Line Width Verification
Industry for Use Defense/Aerospace
Standards Met IPC-6018 Microwave End Product Board Inspection and Test
IPC-A-600 Acceptability of Printed Boards