工艺技术3刻蚀.pptxVIP

工艺技术3刻蚀;讲座提要;1.1 General;Isotropic etch (无定向刻蚀);1.2 Facility;2.0 Wet etch ;2.1.1 Wet etch mechanism （湿化刻蚀机理）;2.1.2 Wet etch byproduct (副产物);2.1.3 Wet etch improvement ;2.2.1 BOE etch ;CD lost in BOE etch（氧化硅刻蚀) ;BOE etch sink （氧化层刻蚀水槽) ;2.3 Nitride etch （氮化硅腐蚀）;2.4 Aluminum Etch(铝刻蚀);Few special issues in Aluminum Etch;2.5 Poly/silicon etch (硅刻蚀）;Wet etch table;DI water rinse equipment Cascade --- Slow, initial bath contain weak chemical QDR (Quick Dump Rinser) Fast, Create ESD (particle), Cycle time, number of cycle Spray rinse --- Run with dryer * Hot DI water is increasing the rinse efficiency;Wafer dry;3.0 Dry etch （干化刻蚀）;3.1 Plasma Theory and application (等离子理论和应用);Often, electrical power is coupled into a plasma by means of parallel metal electrodes The acceleration of electrons is the principal means by which energy is coupled into the plasma. The amount of energy gained by a electron is equal to the force on it times the distance;第23页/共82页;Plasma density In a plasma, we have seen that new free electrons are generated by electron-impact ionization gas atoms and molecules. At the same time, many of electron lost to the electrode and other surrounding surface. So the plasma stabilize at a density of electrons for which the generation rate is balanced by the loss rate. This stabilized electron level is called the plasma density.;For a given reactor, plasma density is determined by four principle inputs: 1. The voltage applied to the electrode Higher applied voltage leads to more electron energy gain between collisions 2. The gas composition The molecule that has weaker molecule bond is easier ignite plasma 3. The gas pressure Gas pressure affects plasma density through the collision rate. In higher pressure –shorter mean free path. At low voltage, too much energy lost in non-ionizing collision and plasma dies out. At high voltage, one electron initials so many ionizing collisions that an excessively conduct path is creat