A technician uses a computer guiding system to align the filter mask in perfect register with the quartz wafer. The filter mask will block light to selected regions of the wafer. More nucleotides can be added to the exposed regions.
A technician prepares to load a filter mask into the photolithography camera. These filters allow the technician to build customized chains of DNA. The blue boxes on the right store 50-100 filters needed to produce a single type of GeneChipÂ™.