Method of fabricating a valve unit

Provided are a valve unit (100,150), a microfluidic device (10) including the same, and a method of fabricating the valve unit (100,150). The method includes: forming a lower substrate (15) including a channel (31) including a first region (101,151) and a second region (107,157) which is deeper than the first region (101,151) and is adjacent to one side of the first region (101,151); forming an upper substrate (20) comprising a valve material chamber (109,159) which extends only partially through the upper substrate (20); filling the valve material chamber (109,159) with a valve material (v) and curing the valve material (v) in the valve material chamber (109,159); attaching a surface of the upper substrate (20) in which the valve material chamber (109,159) is formed to a surface of the lower substrate (15) in which the channel (31) is formed, so that the valve material chamber (109,159) overlaps an overlapped portion (102,152) of the first region (101,151), and does not overlap a non-overlapped portion (103,153) of the first region (101,151); melting the valve material (v) accommodated in the valve material chamber (109,159) to flow the valve material (v) into the non-overlapped portion (103,153) of the first region (101,151); and curing the valve material (v) flowed into the non-overlapped portion (103,153) to close the first region (101,151).