Patent ID: 7998780
Filing Date: 2011-08-16
Classification: H01L

Abstract:
1. A method of fabricating an image sensor with thinned silicon substrate, comprising the steps of: providing a front surface of a silicon substrate; depositing at least one insulating layer and a first patterned conductive layer onto said front surface; transferring the front surface of the silicon substrate onto a transfer substrate; thinning the silicon substrate down to a thickness of a few micrometers; forming at least one localized contact opening on a rear surface of the thinned silicon substrate, wherein the at least one localized contact opening is located within a surface area for an external connection terminal of the image sensor and the at least one localized contact opening further exposes a portion of said first patterned conductive layer; depositing a second conductive layer on the rear surface of the thinned silicon substrate, said second conductive layer contacting the thinned silicon substrate in said surface area and contacting the first patterned conductive layer in the at least one localized contact opening; etching the second conductive layer to form a localized external connection terminal of the image sensor, said localized external connection terminal entirely comprised within said surface area; and forming a peripheral trench through the entire thickness of the thinned silicon substrate to said insulating layer located under the thinned silicon substrate, the peripheral trench completely surrounding said surface area for an external connection terminal, wherein a bottom of the peripheral trench is entirely formed by the insulating layer, so as to form an island of the thinned silicon substrate having the localized external connection terminal formed thereon, said island being insulated from remaining portions of the thinned silicon substrate outside said surface area.