A fluid sample analyzing system may be formed from an image sensor integrated circuit substrate. A glass wafer may be used to cover a wafer of image sensors. The glass wafer and the image sensor wafer may be attached using oxide bonding. Fluid channels may be formed in a layer that is interposed between the image sensor wafer and the glass wafer. The layer may be deposited on the image sensor wafer and the glass wafer prior to oxide bonding. A spacer may be used to deliver the fluid channel layer to the image sensor wafer before the glass wafer is bonded to the image sensor wafer. The spacer may be formed from a silicon wafer. The silicon wafer may be bonded to the image sensor wafer and thinned, leaving a thin spacer wafer layer on the image sensor wafer in which fluid channels may be formed.