Thermocompression bonding can be used for wire bonding or Flip Chip bonding. It needs contacts made of ductile materials, e.g. stud bumps created from Au wires. These can be located on either the substrate or component. On the opposite side, flat contacts, preferably of the same material, serve as bonding partners.

Without the necessity of liquefying the contact material, thermocompression bonding generates a joint by material engagement, providing acceptable mechanical firmness and steadiness as well as a good electrical conductance. Especially in connection with Flip Chip bonding, this process improves the RF properties of the bonding joint.

  • Au stud bump thermocompression bonding
    Au stud bump, magnification 300x, ø ≈ 50 µm

What are the Challenges?

  • Apply force and heat to the component simultaneously
  • Minimize substrate heater's compliance to absorb bonding force without deformation
  • Prevent thermal drift of heated area over a large temperature range (requires sophisticated support elements in connection with thermally compensated materials)
  • Provide thermally and mechanically stable component heater
  • Provide stable, fine resolution bonding force control to bond even the thinnest and most brittle materials, as well as large components with lots of bumps
  • Achieve micron range coplanarity between component and substrate (requires adapted tooling or sensors and activators to detect and compensate deviations)

The Finetech Solution

Principle of Thermocompression Bonding

  • Principle of thermocompression bonding
    Principle of thermocompression bonding

To create a Thermocompression joint, component and substrate are first heated to roughly 300°C, and then pressed together for about half a second with defined bonding force. The joint builds up by diffusion welding and can be burdened immediately.

Thermocompression Parameters

  • bonding of Stud bumps on Au layer
    Stud bumps on Au layer

Gold (Au):
T = 200 … 320ºC
F = 0.1 … 0.7 N/bump

Indium (In):
T > 60ºC
F = 0.02 N/bump

FINEPLACER® Bonding Systems

  • FINEPLACER® femto 2
    Automated Prototype2Production Bonder
  • FINEPLACER® sigma
    Semi-automated sub-micron bonder
  • FINEPLACER® lambda
    Flexible sub-micron die bonder
  • FINEPLACER® pico ma
    Multi-purpose die bonder
  • FINEPLACER® pico ama
    Automated flip chip bonder
  • FINEPLACER® matrix ma
    Semi-automated die bonder

Due to the modular design approach, FINEPLACER® bonding systems can be configured for virtually any application challenge.

The main distinguishing features between the machines are the

  • degree of automation
  • optical resolution and
  • placement accuracy

Browse our product range or get in contact with your sales contact to figure out the best equipment solution for your specific application requirements.