Development of Low-temperature Sinterable Ag Nano Paste
04/13/2022
Motivation
Wider IoT availability calls for more flexible applications. Materials for flexible application must be processed at low-temperature. Wiring materials in such applications require good electrical conductivity and flexibility in a thin film form.
Issue
Ensures low-resistance wiring in low-temperature processes to support organic substrates with low heat resistance
Results and Findings
- Successful development of Ag paste which provides specific resistance of 7.1 x 10-6 Ω·cm by sintering at 120℃/30 minute drying
- For wiring with this paste, screen-printing is supported.
Background of the Issue
Motivation for the Development
- Wider IoT availability calls for more flexible applications.
- Materials for flexible application must be processed at low-temperature, which requires wiring materials to provide good electrical properties and flexibility in a thin film form.
- In the automotive sector, there will be increasing demand for more advanced cameras and sensors for autonomous driving, as well as demand for snow melting and anti-fogging solutions to support the increase in the number of cameras and sensors installed in automobiles. This indicates a potential demand for heaters.
Overview of the Development
Conventional Ag paste for wiring/electrode formation can be sintered at 120℃/30 minute drying; however, the conductivity is provided only through Ag particles in the paste, which limits specific resistance to up to 2.5 x 10-5 Ω·cm.
Concept of the Development
- Targets low resistance by sintering Ag filler at 120℃/30 minute drying.
- Ensures flexibility on a thin film with uniform sintering.
- Ensures adhesion to film substrates made of materials such as PC, PET, or PI by adding resin components.
Developed Technology
Sintering Ag filler at 120℃/30 minute drying
Results and Findings
- Good sintering of Ag filler at 120℃/30 minute drying
- Specific resistance of 7.1 x 10-6 Ω·cm achieved
- Screen printing supported for micro wiring with 6 μm film thickness and 250 μm width
- Good adhesion and bending resistivity to film substrates made of materials such as PC, PET, or PI
- No deterioration of resistance after long-term reliability test
Ag wiring screen printed at 120℃/30 minute drying
Cross-sectional view by FIB (Magnification: 10,000 x / 25,000 x)
Prospective Applications
- Low-resistance wiring
- Printable heating wires
Heat generation image of printable heater using Ag electrodes