Patent ID: 8531565
Filing Date: 2013-09-10
Classification: H01L

Abstract:
1. A method of forming a backside illuminated image sensor, the method comprising: ion-implanting a guard ring structure of a predetermined depth in a front-side surface of a semiconductor substrate, the guard ring structure forming a two-dimensional array of pixels, each pixel of the array of pixels separated from an adjacent pixel by the guard ring structure; forming at least one image sensing element on the front-side surface of the semiconductor substrate, the at least one image sensing element being formed in a pixel of the array of pixels and surrounded by the guard ring structure; and reducing a thickness of the semiconductor substrate to a predetermined thickness by removing material from the back-side surface of the semiconductor substrate, wherein the thickness of the semiconductor substrate is reduced until the guard ring structure is co-planar with a back-side surface of the semiconductor substrate, whereby the guard ring structure extends from the front-side surface to the back-side surface of the semiconductor substrate having the reduced thickness.