초록 ▼

A method of filtering a bath (1,31) having a liquid containing particles of varying sizes therein and the recirculation and filtering system. The method and system require providing a recirculation route from the bath outflow and returning to the bath inflow. The route includes a first path communic

A method of filtering a bath (1,31) having a liquid containing particles of varying sizes therein and the recirculation and filtering system. The method and system require providing a recirculation route from the bath outflow and returning to the bath inflow. The route includes a first path communicating with the bath outflow and having serially a first controllable valve (5,9) and a filter having a relatively large pore size. The route also includes a second path communicating with the bath outflow and having serially a second controllable valve (11,15) and a filter having a relatively small pore size. There is a return path from each filter to the bath inflow. The return path from each filter can be a separate path or the paths can be connected at the output end before returning to the bath. The particle count in the recirculation route can be monitored either between the bath outflow and the first and second valves (3), between the bath inflow and each of the filters having large and small pore size (23), or both for controlling operation of the first and second valves. The controllable valves can also be controlled by a time program, bath operation program or the like.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of filtering a liquid disposed in a bath for use in conjunction with the fabrication of semiconductor devices, said liquid containing particles of varying sizes therein which includes the steps of:providing a bath and a pair of independent recirculation routes

[ What is claimed is:] [1.]1. A method of filtering a liquid disposed in a bath for use in conjunction with the fabrication of semiconductor devices, said liquid containing particles of varying sizes therein which includes the steps of:providing a bath and a pair of independent recirculation routes from said bath and returning to said bath including a bath outflow from said bath to said pair of recirculating routes and a bath inflow from said pair of recirculating routes to said bath:(i) the first of said pair of recirculating routes directly communicating with said bath outflow and said bath inflow and having serially a first controllable valve and a first filter having a relatively large pore size having pores of from about 0.2 to about 2.0 micrometers; and(ii) the second of said pair of recirculating routes directly communicating with said bath outflow and said bath inflow and having serially a second controllable valve and a second filter having a relatively small pore size of from about 0.001 to about 0.2 micrometers;(iii) said first and second routes each providing a return path from each of said first and second filters to said bath inflow passing said liquid from said bath along the associated recirculation route and back to said bath;monitoring the particle count in each of said recirculation routes; and trolling said first and second controllable valves individually in response to said particle count.