Disclosed are apparatus and methods for monitoring a characteristic associated with a product feature on a semiconductor product. A proxy target formed from at least one substructure that corresponds to a product feature is provided. The substructure is not individually resolvable by an optical tool. A characteristic of the proxy target is determined based on optically monitoring the proxy target using the optical tool. Based on the determined characteristic of the proxy target, it is then determined whether the corresponding product feature has a characteristic that is within a predetermined specification or whether a process parameter used to fabricate such product feature is within a predetermined specification. In a specific embodiment, the characteristic of the corresponding product feature includes a shape parameter and a position parameter.