Photolithography is a key component of the industry's ability to continue to shrink devices according to Moore's Law, and any improvements immediately translate into large economic benefits for the industry. The relative contribution of the "wetware," i.e., the photoresists and other chemicals used in the photolithography step, versus the contribution of the exposure tool development is investigated by expressing the resist performance improvement as a numerical aperture (NA). Using this "equivalent NA" concept, it is shown that the contribution from resist improvements has historically outpaced that from stepper NA improvements. However, R&D expenditures for hardware and wetware have consistently been at greatly different levels. While part of that difference is probably intrinsic in the cost structure of the respective development efforts, it is suggested that the relative amount of spending on resist R&D has historically not been at a level that optimizes the overall return for the industry.