Connection at Room Temperature

With KlettWelding, two substrates prepared with NanoWiring are instantaneously joined together by compression (e.g., 20 MPa) at room temperature. The needed pressure and force correlates with the size of components and it can be applied with commercial SMT placement equipments or FlipChip bonders. Broad-area connections can be made using an electro or hydraulic pressing machine. But it is also possible to use a simple toggle presses.
Also after even more than one year of storage the KlettWelding connections can easily be produced using the KlettWelding-Activator.
In very robust application areas, KlettWelding tape can be used to thicken the connection zone, like artificial hair extensions.

Due to their small diameter, the individual wires connect instantaneously mechanically at crystal-lattice level – similar to cold welding. The resulting joint has comparable electrical and thermal characteristics as rolled copper while maintaining high mechanical strength. The video below shows the KlettWelding process of a silicon chip with copper pillars, performed with a flip chip bonder.


Step Back: NanoWiring (Coating)


Properties of the connection :

Properties

Value

necessary bonding pressure

1 – 70 MPa (typically 20 MPa)

Shear strength

up to ca. 30 MPa (typically 12 MPa)

Tensile strength

up to ca. 20 MPa (typically 12 MPa)

Peeling strength

Up to ca. 1.7 N/mm (typically 1.2 N/mm)

KlettWelding temperature

From room temperature

Bonding time

60 ms to 60 s

Temperature tolerance

-50°C-500°C

Contact electrical resistance

< 1 µΩ/mm²

Thermal conductivity

350 W/m⋅K

Planarity requirements

Approx. 1/2 length of NanoWiring

Contact height

Approx. 1/3 length of NanoWiring

Wire material

Copper Gold, Nickel, Silver, Platinum, Tin

NanoWiring diameter

30 nm to 2 µm (typically 1 µm)

NanoWiring length

500 nm to 50 µm (typically 10 µm / 25 µm / 50 µm)

Substrate Materials

Copper, aluminum, stainless steel, gold, ceramics (including LTTC), polymer (PI, PCB), glass


KlettWelding von Copper Pillars

KlettWelding schematisch