Laser Polishing/Planarization Process

CAMP Professor Daryush Aidun's research objectives are to design and develop an alternative method to CMP that is an optical process for the polishing and/or planarization of wafers.

In an attempt to accomplish this objective, he is investigating the use of excimer lasers to remove materials by breaking their chemical bonds and vaporizing them. The first and most important part of this research is to determine the feasibility and the practicality of a laser polishing/planarization (LPP) process. The next step is to make conceptual designs of the LPP processes and to finally construct a "prototype" process using the excimer lasers to polish silicon wafers. Professor Aidun is currently modeling various aspects of this work with collaborators CAMP Professor Cetinkaya and Mr. Postgate. The advantages of such a process are its lower cost, higher productivity, and its friendliness to the environment.

In addition Professor Aidun and a group of students ( Michael P. Kozar, Luke Simmons, John Ingraham, Anne Peairs, Matt Braun, and Matt Vogel), in Professor Eric Thacher's Integrated Design course at Clarkson University, are carrying out a welding design project. They are designing and developing an automated dual-head arc welding process with a built-in weld fume exhaust system. This unique process, which is environmentally friendly, will increase efficiency and productivity.



CAMP's Dr. Dana Barry Serves as Visiting Professor in Japan
  During the month of August, CAMP Editor and Technical Writer Dr. Dana Barry served as a Visiting Professor at Suzuka National College of Technology (SNCT) in Japan. She presented college lectures, which aired on television in Japan, about Chemical-Mechanical Polishing and her World First Space Missions. She also gave Science Sensation and Faculty Development Seminars. In addition, she taught chemistry classes at Takada High School in Japan using an innovative method which incorporates music and science experiments to present and reinforce concepts. Dr. Barry developed this unique method in collaboration with Professor Hideyuki Kanematsu of the Department of Materials Science and Engineering at Suzuka. Other Suzuka professors working on this project are Tatsumasa Kobayashi and Hiroshi Shimofuruya. This project is sponsored by Suzuka National College of Technology and the Northern New York Section of the American Chemical Society. Dr. Barry is preparing a feature article about this international effort for the January 2003 issue of the Japanese chemistry research journal the Bulletin of the Tokai Kagaku Kougyoukai (The Society of Midland Chemical Industries). Dr. Barry, a certified professional chemist and external professor for Ansted University in Malaysia, has over 80 professional publications and many honors and awards to her name.

Pulsed Laser-Based Nanoparticle Removal and Nanoadhesion Measurements

Professor Cetin Cetinkaya and his group have been conducting analytical, computational and experimental work in the area of laser- based particle removal and noncontact nanoadhesion measurement. There is an immense need in various industries for dry removal of submicron particles from substrates and trenches. Professor Cetinkaya's group has developed a novel dry cleaning method to remove micron and submicron particles. The new technique, based on laser-induced plasma shock waves, is a noncontact method and the removal efficiency is an order of magnitude higher than the traditional laser cleaning methods. This work involved a surface that was polished copper with gold plating. The dry laser cleaning method is being used to remove micron and submicron particles from varying substrates as well as from micro-holes and semiconductor trenches. The new cleaning method has demonstrated a great potential in the area of nanoparticle removal. Various applications of this technology are being investigated by Professor Cetinkaya's group. A recent National Science Foundation grant entitled "Exploring the Limits of Nanoparticle Removal with Pulsed Lasers" was awarded for this research.

Modeling of the Chemical-Mechanical Polishing Process

Professor Ahmadi and his group are developing a model (based on mechanical contact theory) for the chemical-mechanical polishing process. The goal of their research is to provide a fundamental understanding of the parameters that control the effectiveness of CMP for surface planarization. Their current work focuses on the abrasive particle, wafer, and pad contact and the abrasive and adhesive wear mechanisms in the chemical-mechanical polishing process. They are developing a model for interactions of pad asperities with abrasive particles and the wafer. Their analysis includes the influence of abrasive particle adhesion to the surface of the wafer. Also they are looking at the CMP process using hard and soft pads and dilute and concentrated slurries. In addition Professor Ahmadi and his students are studying the effect of abrasive particle shapes, slurry pH, and colloidal forces on the removal rate.

Their model predictions are described in detail and compared with the available semi-empirical correlations in the paper " A Model for Mechanical Wear and Abrasive Particle Adhesion During the Chemical-Mechanical Polishing Process," by G. Ahmadi and X. Xia, Journal of the Electrochemical Society , 148 (3) G99-G109 (2001).


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