Sintering is the thermal treatment of a powder or compact at a temperature below the melting point of the main constituent, for the purpose of increasing its strength by bonding together of the particles.
Sintering with silver is increasingly used as an alternative to soldering. Being rather costly, it is mainly restricted to high power electronics (power laser, power switch, transistors, etc.) dependent on high thermal and electrical conductivity.
Unlike soldering with Au/Sn or alloys with even higher melting points, sintering with silver nano balls (small volume combined with a large surface) does not require the material to melt. Instead, high force and moderate heat input of around 200-300 °C is used to bond together the silver particles. The good properties of silver (such as a high melting point of close to 1000 °C) allow the full benefit from silicon as the substrate material in high-temperature environments.
Sintering can be done with paste or foil. Liquid phase sintering with silver paste dispensing is simple but the paste may bleed out during bonding. Another disadvantage is that vapor might pollute the facettes of optoelectronic components. Therefore, an alternative is to use sintering foil with dry nano silver powder which is applied onto the chip by pressing the chip onto the powder before bonding it to the substrate. The connection is made by force, temperature and time, resulting in a diffusion process.
With FINEPLACER® sigma, Finetech offers a high force bonder for direct sintering applications. Placing and sintering can be done in one single step with forces up to 1000 N. In addition, all Finetech bonders are capable of pre-sintering before the sintering press, i.e. for high-precision applications like single laser bonding.
The Finetech Solution
- High force bonding up to 1000 N
- Nano silver powder foil, no bleeding
- Placing and sintering in one process, no additional handling step required
- Pre-sintering process available on all bonders
Recommended FINEPLACER® System
FINEPLACER® sigma - a semi-automatic bonding system providing sub-micron accuracy, high force bonding up to 1000 N and 300 mm wafer support.
FINEPLACER® femto 2 - fully-automated die bonder with a placement accuracy of 0.5 µm @ 3 sigma.
Browse our product range or get in contact with your sales contact to figure out the best equipment solution for your specific application requirements.