A method and system for assembling a device by picking up semiconductor devices from a carrier substrate and placing the semiconductor devices onto a target substrate. The transfer of the semiconductor devices uses fluid as a transfer medium. The fluid enters a fluid channel of a pickup head, causing the pickup head to expand, make contact with, and attach to an aligned semiconductor device. After the semiconductor device is aligned with and placed onto the target substrate, at least a portion of the fluid is removed from the pickup head to release the semiconductor device onto the target substrate. The semiconductor device bonds to the target substrate.