METHOD AND SYSTEM FOR ETCHING SILICON NITRIDE LAYER TO MINIMIZE VARIATION OF ETCH RATIO OF SILICON NITRIDE LAYER

摘要

PURPOSE: A method and a system for etching a silicon nitride layer are provided to minimize a variation of etch ratio of the silicon nitride layer by maintaining constantly the etch ratio of the silicon nitride layer. CONSTITUTION: A temperature recovery time for phosphate solution is stored according to the number of wafers and the sizes of wafers(S1). The number and the sizes of wafers dipped into the second chemical bath are detected(S2). The temperature recovery time is produced according to the number of wafers and the sizes of wafers dipped into the second chemical bath(S3). A wafer dipping time of the second chemical bath is controlled by using the temperature recovery time(S4).