Semiconductor photovoltaic cells have surfaces that are textured for processing and photovoltaic reasons. The absorbing regions may have parallel grooves that reduce loss of solar energy that would otherwise be lost by reflection. One form of texturing has parallel grooves and ridges. The cell also includes regions of metallization for collecting the generated electrical carriers and conducting them away, which may be channels. The topography is considered during production, using a process that takes advantage of the topography to govern what locations upon will receive a specific processing, and which locations will not receive such a processing. Liquids are treated directly into zones of the cell. They migrate throughout a zone and act upon the locations contacted. They do not migrate to other zones, due to impediments to fluid flow that are features of the surface texture, such as edges, walls and ridges. Blocking liquid may also be deposited and migrate within a zone, to block or mask a subsequent activity, such as etching.