The present disclosure is directed to a method for reducing the surface deformation of a color filter after a baking process in an image sensor device. Surface deformation can be reduced by increasing the surface area of the color filter prior to baking. For example, forming a grid structure over a semiconductor layer of an image sensor device, where the grid structure includes a first region with one or more cells having a common sidewall; disposing one or more color filters in a second region of the grid structure; recessing the common sidewall in the first region of the grid structure to form a group of cells with the recessed common sidewall; and disposing another color filter in the group of cells.