Particle Reduction and Taguchi Analysis for Semi-conductor Plasma Etching Equipment

• Main Authors: Yen-JungWei, 衛彥榮
• Other Authors: Long-Sun Cha
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/69663265390727936086

碩士 === 國立成功大學 === 工程科學系碩士在職專班 === 104 === Based on the competition of semiconductor in the world up to the twelve inch wafer, the yield of the wafer is an indicator of the enterprise viability in career, which inspires the study motivation of the thesis. Yield rate can be observed in three areas: the production management, processing ability and machine equipment. The new process needs to obtain the customer certification and the strict defect detection could enhance the reliability of the product certification. The transformer coupled plasma etching is extensively used in semiconductor etching processes. It is imperative to study on the fine particle pollution of the plasma etching. This study area is focused on the twenty nanometers dry etching process. During the poly layer etching process, the fine particle residual phenomenon would cause wafer contamination. If it cannot be intercepted by the in-time scanning, it would contaminate the following process equipment and decline the yield. During the plasma etching, the chamber ESC (Electrostatic Chuck) executes the electrostatic attraction and repulsion actions to the wafer. As the RF (Radio Frequency) time increases and the ratio of the number of wafer going through the poly etching process to the execution number of WAC (wafer auto clean) process deceases, the induced electrons are raised. This would lead to the poor surface repulsion and the formation of large number residual electrons. The electrons are transmitted directly to the wafer surface, which would attract the free molecules in the reactor and the ions after the reaction. The molecules and ions are attached to the edge surface of the wafer. When the plasma is produced in the process, the absorbed electrons on the wafer, reacted with the plasma, are taken away, but the free molecules and reacted ions (fine particles) remain on the wafer. The study purpose is to find a fundamental solution using the following steps. Step 1 is to analyze the plasma characteristics and the detention process of fine particles. Step 2 is to establish an experimental model of poly plasma etching process using the Taguchi method to study the interaction among plasma, fine particles and residual charges. The operating parameters of the plasma etching equipment are plasma power, bias power, pressure and gas flow rate of helium, adsorption voltage, pressure and flow rate of helium, detection of wafer location deviation. The target of the experimental design is to find out the residual electrons. Step 3 is to improve the etching process by adjusting the operating parameters through the study of the established experimental model. This is the primary purpose of the thesis.