An image sensor with on-die diffractive optics in 0.18μm bulk CMOS

Abstract

On-die optics are an attractive way of reducing package size for imaging and non-imaging optical sensors. While systems incorporating on-die optics have been built for imaging and spectral analysis applications, these have required specialized fabrication processes and additional off-die components. This paper discusses the fabrication of an image sensor with neither of these limitations. Through careful design, an image sensor is implemented that uses on-die diffractive optics fabricated using a standard 0.18µm bulk CMOS process, with simulations indicating that the resulting die is capable of acting as a standalone imaging system resolving spatial features to within ±0.15 radian and spectral features to within ±40 nm wavelength accuracy.