Techniques for glass attachment in an image sensor package

A low-cost wafer-level packaging (WLP) method for attaching glass to optical image-sensor devices on a semiconductor wafer in order to increase the yield of image-sensor modules during later steps of assembly. One embodiment relates to applications with image-sensors (and microlenses) fabricated on a wafer. A glass wafer is singulated, aligned to mirror the die pattern on an image-sensor wafer, and then bonded to the image-sensor wafer such that optical adhesive forms a layer between the each image-sensor and its glass cover. Another embodiment applies cavity walls to singulated glass covers, which are then attached to image sensors which may be formed on a single wafer. The wafer can then be singulated and a plurality of image sensor packages is formed.