Newly Developed Low-Reflectivity Black Resist with High Optical Density

The black resist has been generally used in a various kind of devices such as displays and CMOS sensors. To improve the device performance, it was required to have high light shielding properties, low reflectance, and high lithographic performance. Furthermore, in recent years, the number of Infra-red (IR) sensor devices had increased, such as time of flight (TOF) sensors, which was required not only for visible light but also for the IR region having shielding layer for both high light-shielding and low-reflective properties. So far, it was difficult to satisfy all these properties, however, newly developed black resist could be achieved all those properties by modifying black materials and the resin components. The resist could be exposed by i-line lithography and compatible with conventional aqueous alkaline development. The resist reflectance was possible to achieve a reflectance below 2% from the visible region to the IR wavelength range. Both 200 µm line & space and 50 µm hole patterns were demonstrated with the newly developed black resist formulation.