Valve unit, reaction apparatus with the same, and method of forming valve in channel

A reaction apparatus comprising:

• a substrate formed of a first layer and a second layer, the first and the second layers being bonded together to form the substrate;
• a fluid channel formed in the substrate and constituting a flow path of a fluid;
• a fluid chamber formed in the channel to receive the fluid;
• and
• a valve unit closing and opening the channel,
• wherein the valve unit includes:
• a portion of the fluid channel which includes a first area of a first depth and a second area of a second depth which is greater than the first depth, wherein the second area is located on one side of the first area, and the first area has a width in a direction of the fluid channel;
• and
• a valve material formed only in the first area of the fluid channel by filling the first area and comprising a phase changeable valve material,
• wherein a direction of the first and second depths is substantially parallel to a direction of irradiation of an external energy used for heating the phase changeable material, and
• wherein the portion of the fluid channel further contains a third area of a third depth which is greater than the first depth, and the third area is located on the other side of the first area.