Chip on Board Assembly

Precision Chip-on-Board (COB) Assembly Services

Chip-on-Board (COB) technology enables high-density, low-profile microelectronic integration by mounting bare semiconductor die directly onto printed circuit boards (PCBs) or specialised substrates. At Reltronix, our UK facility provides end-to-end COB assembly solutions designed to reduce form factor, eliminate package parasitics, and lower total production costs for demanding industrial, aerospace, and medical applications.

By integrating direct die placement, ultra-fine interconnects, and protective glob-top encapsulation under strict cleanroom conditions, we deliver robust assemblies tailored to customer-supplied substrates and circuit layouts.

Core Capabilities & COB Workflow

• Direct Bare Die Attachment
  Automated placement of silicon, GaAs, and GaN bare die onto circuit boards using high-performance conductive or non-conductive adhesives via our die attach services.
• Micro-Wire Interconnects
  High-density, high-reliability interconnects using Gold (Au) ball, Gold wedge, or Aluminium (Al) wedge wires applied through our precision wire bonding services.
• Glob-Top & Dam-and-Fill Encapsulation
  Automated dispensing of protective epoxy and silicone encapsulants to shield fragile wire bonds and bare die from environmental moisture, chemical exposure, and mechanical stress.
• Gold Stud Bumping & Flip Chip Options
  Advanced direct surface-mount options using flip chip and die bumping for high-frequency or ultra-compact designs.

Quality Control & Reliability Assurance

To ensure long-term performance under harsh thermal and mechanical conditions, every COB assembly is backed by our comprehensive in-house mechanical qualification suite:

• Bond Adhesion Testing
  Verification of die bond shear strength using MIL-STD-883 compliant die shear testing.
• Interconnect Integrity
  Rigorous destructive and non-destructive wire bond pull testing to evaluate wire loop strength and bond interface quality.
• Visual Inspection
  Manual optical inspection under high-magnification microscopes to evaluate die attach fillets.

Key Advantages of COB Assembly with Reltronix

• Substrate Flexibility
  Equipped to assemble directly onto customer-supplied FR4, polyimide, insulated metal substrates (IMS), and ceramic carriers.
• Miniaturisation & Mass Reduction
  Eliminates individual semiconductor packaging footprints, reducing total board space and overall device weight.
• Flexible Turnkey or Modular Processing
  Choose full subcontract management or utilise specific stages such as wire bonding or glob-top dispensing to resolve a capacity constraint in your production line.