A negative photosensitive polyimide developed by Toray Industries maintains the characteristic thermal resistance, mechanical properties, and adhesion of the material while increasing resolutions and enabling high-definition pattern formation on 100-micrometer and other thick films.
To accommodate the increased speed and capacity of 5G and 6G networks, smartphones and other mobile devices will require more miniaturized electronic components and higher density mountings. This will necessitate more refined fabrication processes for the insulating layers of electronic components.
These layers typically use negative photosensitive polyimide materials. While they provide chemical resistance and reliability, the materials are disadvantaged by low light transmission. Photosensitivity deteriorates when thicknesses exceed 50 micrometers, preventing fine processing. Other issues include high thermal stresses after curing and significant warping, reducing reliability during processing.
Toray’s new negative photosensitive polyimide material is 100 micrometers thick with vias measuring 10 micrometers in diameter. The company leveraged its expertise in functional polyimide design technology to enhance light transmittance and control photo reactions to achieve this breakthrough.
|The material will be commercialized in sheet and varnish forms.|
Toray also reduced thermal stress in the new material, which is less than half of conventional polyimide. Warping is reduced by controlling polyimide resin cross-linking density from photo reactions during exposure and lowering curing shrinkage.
This material should make it possible to miniaturize electronic components and semiconductor package wiring and enhance reliability, according to Toray. It is shipping prototypes with a view to commercializing the material as a varnish and sheet.
Toray plans to augment its lineup with grades having low thermal expansion coefficients and dielectric levels and small dielectric losses for semiconductor devices and electronic components that can drive ultrafast communication technologies.