Conference Program - LOPE-C 2011

SCIENTIFIC CONF. | WEDNESDAY-JUNE 29, 2011
Track 4
Printing Technologies (11:30 am - 01:20 pm) | LOCATION HARMONIE D / LEVEL C2
11:30 am Optimized process for S2S and R2R screen printing of conductive structures for plastic electronics applications
Mr Eric Rubingh,
Holst Centre, Senior process engineer, Netherlands
Requirements for printed conductive structures within plastic electronics applications, such as electrode grids in OLED and OPV devices and HF antennas and circuitry in
smart packaging applications, are challenging. A deposition process, capable of small feature sizes with high quality line formation and sufficient deposition amounts to
reach the required conductivity, is needed. As speed and cost of processing is important, we chose for a single step R2R compatible screen printing process, capable of
sub 100 µm feature sizes with high deposition amounts, and combined this with an in house build R2R photonic sintering tool. Although inkjet and flexo printing both have
their own benefits and can easily reach the targets set for feature sizes, they both require either a multi layer print approach or an additional process to reach the required
conductivity for the mentioned applications.
In this paper we present results of a study on optimizing the print quality of both S2S and R2R screen printing of commercially available nano and micron particle silver
pastes, using both oven and inline photonic sintering. The traditional way to achieve feature sizes of sub 100 µm with flatbed screen printing is using high mesh number
woven meshes. However, the disadvantage of these woven meshes is the decrease in deposition amount with increasing mesh number, resulting in less thick lines and
thus lower conductivity. By using an optimized electroformed nickel mesh technology we were able to increase the amount of deposited material, with better print quality
and dimensional stability compared to ?standard? woven mesh technology. The knowledge obtained with the flatbed screen print experiments was used to facilitate the
step towards R2R printing with a rotary screen print tool, using the same electroformed meshes and materials as with the flatbed screen print experiments. Finally we
compare obtained results with the requirements for several applications.
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