ASHING PROCESS FOR FORMING VIA CONTACT

摘要

PURPOSE: An ashing process for forming a via contact is provided to remove effectively a TiN foot from a via profile or a polymer from a sidewall of a via contact. CONSTITUTION: A hard polymer is generated from a via contact sidewall in a via etch process. A photoresist/polymer is easily hardened when the hard polymer is contacted with a high temperature plate of 250 degrees centigrade. The photoresist is fully removed by using a mixed gas of O2+H2N2 or O2+N2 in a state of plasma. A wafer is loaded on the high temperature plate by a pin down method and a polymer is removed from the via contact sidewall by adding an etching gas such as a CF4 gas. A TiN foot is removed from a lower portion of the via contact by performing an isotropic etch process.