Patent ID: 8168933
Filing Date: 2012-05-01
Classification: H01L

Abstract:
1. A method for forming an image sensor, comprising the steps of forming a number of pixels on a surface of a substrate; forming a dielectric layer on the substrate overlying the number of pixels; forming a patterned hardmask layer overlying a top surface of the dielectric layer, the patterned hardmask layer having a number of openings extending therethrough and disposed about the number of pixels; forming a number of trenches within the dielectric layer using the patterned hardmask layer, each of the number of trenches having sidewall surfaces substantially perpendicular to the surface of the substrate, and each of the number of trenches disposed about one of the number of pixels; and forming a layer of material on the sidewall surfaces of the number of trenches, the layer of material comprising a metal to form annular reflective waveguides disposed about each of the number of pixels wherein the step of forming the number of pixels on the surface of the substrate comprises forming the number of pixels comprising a pitch between each of the number of pixels parallel to the surface of the substrate selected to match a wavelength of light incident on the image sensor, and wherein the step of forming the layer of material on the sidewall surfaces of the number of trenches comprises forming the layer of material on the sidewall surfaces of the number trenches such that the plurality of annular reflective waveguides comprise a cross-sectional dimension parallel to the surface of the substrate selected to match the wavelength of light incident on the image sensor.