PCB Manufacturing Yield & PCB Cost Drivers

PCB Manufacturing Yield & PCB Cost Drivers | Printed Circuit Boards in India

Factors Impacting PCB

• Yield will impact cost, as PCB technologies are Some of the major factors impacting yield, are as follows:
  • Aggressive PCB design geometries, i.e. *
    • Trace and space less than 4 mils (0.1mm)
    • Drills less than 10 mil dia. (0.25mm)
    • Pads less than drill dia. + 10 mil (0.25mm – dependant upon copper weight & class)
    • Aspect ratio greater than 10:1
    • Drilled hole to copper less than 8 mils (0.2mm)
    • Anti-pads are less than drilled dia. + 20 mil (0.5mm)
  • Non-standard electrical and mechanical specifications that are not statistically possible in a standard manufacturing process
    • Example – tight hole positional tolerance for alignment
    • PCB fabricators are not machine shops!
  • The complexity of the manufacturing process. An increase in “index number” results in a higher probability of yield loss
    • HDI is the key contributor to a higher index number
  • More aggressive geometries are normal however their impact on yield should be evaluated early in the design

PCB MANUFACTURABILITY AND COST DRIVERS

• What factors drive PCB to cost?

• Choice of materials
• Layer count
• Performance class (IPC 6012B Class 2/3, MIL-PRF-31032, …)
• Manufacturing panel utilization (how PCBs fit on a master panel)
• Basic process complexity, including minimums/maximums for:
  • Line and space,
  • Drilled hole size,
  • Overall PCB thickness,
  • Annular ring requirements,
  • Copper weights,
• Enhanced process operations (via-in-pad, buried capacitance, buried resistors, castellations, )
• Process yield

Summary

• Rules of thumb for cost

• Investigate how PCBs will fit into a production panel to ensure that maximum material utilization occurs
• Use a smaller line width/space before adding layers
• Use smaller holes before adding layers
• When using tighter impedance tolerances, ensure that the materials used do not cancel out these gains
• Hole-fill (VIPPO) is an effective way to achieve higher density
• Add laser blind vias (one or two sides) before burying vias
• Laser and buried vias allow for better yields than mechanical blind vias
• Add staggered laser vias before stacked vias
• Consider hybrid builds for a performance/cost-benefit

Cerra Systems is the largest supplier of PCB and custom assemblies. We supply low to high layer count Printed Circuit Boards in India. At Cerra Systems we focus on medium to high complexity printed circuit board design solutions that meet or exceed all of our customer’s electrical and mechanical constraints. We have established standards for acceptance and delivery which results in faster turnaround time.

For more details, visit us:- http://cerrasystems.com/

Manufacturing Partners Profile includes: 
Argus Sytems (AESPL) –  PCBA, Cable Assembly, Box Build. 
Emsxchange – PCBA, Cable Assembly, Box Build.