Femtosecond laser pulses are used to drill high-aspect-ratio microchannels from the rear surface of silica glass, which is in contact with water. The relationship between the diameter of the channel and the incident energy of laser pulses is investigated. The diameter of the channel was varied from 2 µm to 50 µm by increasing the energy. The morphology of the entrance and inner walls of the channels was analyzed by scanning electron microscopy. The capillary phenomena in the dead-end microchannels in contact with water are investigated. The realization of circular three-dimensional channels is demonstrated.