METHOD AND APPARATUS FOR WET-ETCHING SEMICONDUCTOR WAFERS

摘要

A method of manufacturing electronic devices, in particular, but not exclusively, semiconductor devices, and apparatus for carrying out such a method, in which method substrates 1, which are provided at a surface 2 with a silicon oxide-containing material 3 to be removed, are subjected, while being divided into successive batches, to a wet treatment in a bath 4 containing a solution 5 of hydrofluoric acid in water. During this wet treatment the conductivity of the solution 5 is monitored and the silicon oxide-containing material 3 is removed, thereby forming ionic components. The monitored conductivity is brought to approximately a desired conductivity at time intervals by adding hydrofluoric acid and/or water to the solution 5 inside the bath 4.In order to improve the process stability of the wet treatment of the successive batches of substrates 1 in the solution 5 of hydrofluoric acid in water, and to lengthen the lifetime of the solution 5, the solution 5 is provided with a basic component MX prior to the wet treatment so that the monitored conductivity of the solution 5 decreases as a result of the removal of the silicon oxide-containing material in between the time intervals of the wet treatment. The basic component MX comprises a cation M(+), which is different from H+, and an anion X(-), which anion is a conjugated base of a weak acid.