NEW DUPONT SCREEN-PRINTED POLYIMIDE CONDUCTOR AND DIELECTRIC COVERPRINT
What does the DuPont Micro Circuit Materials Group do? They make pastes for window defoggers on the rear window of your car, pasted for solar cells, membrane touch switches, bio test strips, hybrid circuits for high reliability applications such as engine control modules in cars or for satellite guidance systems. They make ink for repeated elongation for wearables and inks that can formed and molded for in-mold electronic applications.
They are the oldest in this business, dating back to 1937 with DuPont 4817N and have over 1,100 products with Global production in US, China and Taiwan. The headquarters as well as the R&D headquarters are located in Wilmington Delaware.
What problems need to be solved? There is a need for a conductive and a non-conductive coverprint product that can be applied in an additive process, that meets the demands of high temperature, 300°C applications. A product that can be printed without having to align parts or undergo die-cutting or lengthy high temperature lamination processes. A product that can provide minimal RF loss while protecting circuitry with thin layers, <30 microns.
How is this new? There are products that exist, polyimide materials; however, they use DMAC, dimethylacetamide which is teratogenic, mutagenic and carcinogenic. This solvent also attacks screen emulsions and is a threat to upper respiratory tract and nervous systems. These reasons makes it impossible to work with in many businesses.
DuPont's new paste uses an environmentally friendly solvent that does not attack screens and does not harm the operator.
The new ink, DuPont KA702 has many attributes versus a traditional film approach:
- Additive technology vs. subtractive processing:
- Less Waste - only print where needed, less or no etching
- Reduced processing time - no lamination time for a printed covercoat 30 minute drying step only
- Reduced labor costs - fewer steps, no hand alignment is needed
- No laser cutting - of the coverlay sheets is needed
- No die-cutting - or stamping of the coverlay sheets is needed
The conductive product, DuPont KA802 also has several beneficial attributes:
- High Conductivity - 5–7 mohms/square@1 mil
- Chemical Resistance - can be plated, resists most solvents
- No Harmful Outgassing - previous generation had an issue
- Additive Technology vs. subtractive
- Less Waste - only print where needed, no etching
- Reduced Labor Costs - fewer steps to make circuitry
- Allows design changes - late in the process
The conductive product, DuPont KA802 is commercially available. The coverprint, DuPont KA702 is in the last stages of testing and development. Samples of both are available. The datasheet for DuPont KA802 and test results for DuPont KA702 are available upon request.