Liquid auto-level apparatus and method

摘要

An HMDS tank for use in an integrated circuit fabrication process includes a tank configured to hold HMDS having an first inlet port configured to receive a carrier gas below an HMDS surface level, an outlet port configured to release said carrier gas saturated with HMDS above the HMDS surface level, and a second inlet port configured to receive HMDS. A sensor is positioned in the tank at a predetermined HMDS level and configured to generate a sensor signal when the HMDS surface level falls below the predetermined HMDS level. A processor is coupled to the sensor and configured to generate a fill signal in response to the sensor signal to initiate introduction of HMDS into the tank through the second inlet port. In another embodiment, the HMDS tank further includes a second sensor positioned in the tank at a low HMDS level. The processor is also coupled to the second sensor and configured to generate an alarm signal in response to the second sensor signal to warn an operator of a low HMDS level in the tank. The alarm signal can instruct the integrated circuit fabrication process to halt until corrective action is taken. An advantage of the invention includes a substantially constant HMDS level that in turn provides a substantially constant concentration of HMDS in the carrier gas which is delivered to the integrated circuit fabrication process. Additional advantages include increased integrated circuit fabrication up-time, reduced contamination and improved efficiency and continuity of the integrated circuit fabrication process.