An etching composition, a method of forming a metal pattern using the etching composition, and a method of manufacturing a display substrate are disclosed. The photoconductor includes an electroconductive substrate; an intermediate layer located overlying the electroconductive substrate; and a photosensitive layer located overlying the intermediate layer. The upper face of the elastomeric diaphragm is in fluid communication with hydraulic fluid in the system so that the elastomeric diaphragm may deflect in response to low frequency vibrations transmitted through hydraulic fluid in the system to effect damping of the low frequency vibrations.