Patent ID: 8197774

Claim:
A microchip comprising a first substrate joined to a second substrate, the first substrate including a trench in its surface, wherein the trench and a surface of said second substrate facing said first substrate form first and second fluid circuits, the microchip further comprising: a through hole or air vent in one of the substrates so as to connect the fluid circuits to outside the microchip, wherein the first fluid circuit is located to a first side of the through hole or air vent and wherein the second fluid circuit is located to a second side of the through hole or air vent, a first projection located at a position between the first fluid circuit and the through hole or air vent, and a second projection located at a position between the second fluid circuit and the through hole or air vent, wherein a separation distance between the first projection and a surface of one of the substrates is smaller than a separation distance between the second projection and the surface of the one of the substrates.