1. A method, comprising: forming a number of mask features from a first mask material on a substrate, including a first feature of full thickness and a second feature having a recess through a portion of the thickness; depositing a second mask material over the mask features; selectively removing the second mask material to leave a number of sidewall features, and a shield portion within the recess; selectively removing a portion of the first mask material to leave the sidewall features, and concurrently protecting the first mask material adjacent to the shield portion to form a composite feature.