Toyo Ink Debuts New Pressure-Less Nano-Ag Sintering Paste

Toyo Ink SC Holdings Co., Ltd., the Japan-based parent company of the specialty chemicals company Toyo Ink Group, announced that its Corporate R&D Division has developed a silver (Ag) nanoparticle paste for die-attach applications.

The newly developed lead-free material can be sintered at low temperatures under both pressure-less and pressure-assisted methods. It has been engineered to meet the need for higher heat resistance and heat dissipation properties of electrical interconnects used in next-generation power electronics, such as silicon carbide (SiC) devices.

Sintered joints using Toyo Ink’s nano-Ag pastes achieve high bond strengths of 40 MPa and higher, making it possible to sustain the high-temperature operations of high-power semiconductors used in electronic applications such as electric vehicles, radio frequency (RF) transistors and light-emitting diodes (LEDs).

Today’s power semiconductors are increasingly required to have high heat resistance and heat dissipation characteristics to meet the industry trends of package miniaturization, increasing wafer sizes, and greater switching frequencies and power densities. Traditional electrical interconnections based on tin or resin cannot meet the needs of such high-power devices due to their poor electrical and thermal conductivities.

Addressing the need for more reliable and better performing interconnects, Toyo Ink researchers in Japan turned to silver paste as a die-attach solution.

“We’re delighted to bring to the global marketplace an advanced silver sintering paste as an alternative solution to conventional die-attach materials,” said Masashi Arishima, division director, Corporate R&D Division of Toyo Ink SC Holdings. “By leveraging our original nanoparticle and paste design technologies, we succeeded in controlling the density of sintered films when applied on to copper substrates by the metal mask or dispensing printing methods.

“This led to the formation of bonding layers with uniform densities and without large voids in the sintered structure,” added Arishima. “As a result, high bond strengths of 40 MPa and higher were achieved. In evaluation tests of automotive electronic devices by our business partners, excellent bonding was realized by dispensing the paste at low temperatures of 230°C to 300°C under both pressure-less and pressure-assisted systems. Moreover, the sintered silver joints exhibit exceptionally high thermal conductivity of 300 W/m-k or higher. Given these results, we believe that advanced silver pastes are capable of delivering the performance and long-term package reliability demanded by today’s high-temperature and high-power applications.”

The new nano-Ag sintering paste from Toyo Ink Group will be featured at the Toyo Ink SC booth 6247 at SEMICON West 2023 in San Francisco, from July 11–13.