公开(公告)号：JPH11304571A

公开(公告)日：1999-11-05

申请号：JP1005099

申请日：1999-01-19

Applicant: UNITED MICROELECTRONICS CORP

Inventor： TEI SEISHI ,  HO BUNRYO ,  KO KOKUHO ,  BA KORYU

IPC: G01F23/292 ,  G05D9/12

Abstract: PROBLEM TO BE SOLVED: To enable the accurate monitoring of the amount of remaining liquid by detecting a liquid level in a liquid container with a liquid level sensor and generating a signal at the time that the liquid level comes down to a predetermined residual level. SOLUTION: A chemical solution 21 such as a chemical reaction agent is stored in a liquid container 20, and its liquid level is detected by a liquid level sensor 27 including an amplifying unit 22 to amplify a detection signal and a fiber photoelectric sensor 23. The chemical solution 21 is flowed out via a capillary tube 25 and is supplied for a spin-on-glass station. The liquid level comes down with the use of the chemical solution 21. At the time when the chemical solution 21 comes down to the tip 26 of the fiber photoelectric sensor 23, a predetermined amount of the solution remains in the liquid container 20. At this time, a signal is generated by the fiber photoelectric sensor 23, is amplified by the amplifying unit 22, and is transmitted to an alarm 28. By this, it becomes possible for a user of the spin-on glass station to know the appropriate timing of filling or exchange of the chemical solution 21.