Applications

The innovation of NBE’s nanoTach® technology comes from proprietary formulation and procedures for making uniform pastes and films of silver powders. In recent years, die-attach based on silver sintering has emerged as a promising lead-free die-attach solution to replace soldering or epoxy curing. However, the process with existing micron-scale silver pastes requires a force in excess of 300 Kg on a 1 cm x 1 cm chip to lower the silver sintering temperature. Using NBE’s nanoTach® pastes or films that can be sintered at low temperature without pressure or under a low pressure, the process is significantly simplified. The nanoTach® technology was recognized with a 2007 R&D 100 Award — a mark of excellence known to industry, government, and academia as proof that the product is one of the most innovative ideas of the year. 

Exmaple Heating Profile for nanoTach® paste:

1.  Dispense or stencil-print the paste onto a substrate.

2.  Place chip on the “wet” silver paste; note: too much pressure should be avoided to prevent making the Ag layer too thin.  A good bond-line thickness before heating is between 50 to 100 microns.

3.  Heat the substrate in open air to 200oC - 250oC at a ramp rate of 5 oC to 7oC/min and soak for 10 to 90 minutes. For higher bonding strength, increase the sintering temperature. To get high bonding strength with larger chips, lower the heating rate.

4.  Cool down to 25oC.

* Requirement on surface metallization: both the substrate and chip surfaces need be either silver or gold for strong bonding strength.