METHOD FOR CONTROLLING DEVELOPING SOLUTION

摘要

PURPOSE:To maintain a specified developing speed at all times and to obviate thickening of a developing circuit pattern and incomplete development by connecting electrodes of a conductivity meter and pH meter to a piping for circulating a developing soln. and continuously measuring and controlling the concn. of the developing soln. and the change in the degree of the contamination thereof. CONSTITUTION:The developing soln. (aq. 2% sodium carbonate soln.) 4 put into the bottom of a developing machine 3 is fed by a piping 6 having a pump 5 for circulating the developing soln. and is injected to both top and bottom faces of a printed wiring board 8 on a conveying belt 7. The electrodes 2 of the conductivity meter and pH meter 1 are connected to the piping 5 to continuously measure the conductivity and pH of the circularing developing soln. The developing soln. is used until the perissible limiting value for the use of the developing soln. which is preliminarily set as desired is attained. The entire amt. of the developing soln. is exchange when the limiting value is attained. The permissible limiting value for the use of the developing soln. is determined by preliminarily preparing the aq. 2% sodium carbonate soln. to be used as the developing soln., dissolving an alkaline soluble photosensitive resist film of a unit area into such aq. soln., measuring the conductivity and pH thereof and determining the measured value as the limiting value.