How to get to Yale How to get to us Contact us Yale University Yale Engineering Yale Electrical Engineering Yale Applied Physics Yale University Center for Microelectronic Materials and Structures P.O. Box 208284 New Haven CT 06520-8284

Cleanroom A major laboratory facility in support of µELM research and education activities is a 2600 sq-ft class 100 Cleanroom that contains equipment for solid state device fabrication, including facilities for photolithography, wet chemical etching, oxidation, diffusion, thermal evaporation, sputtering, reactive ion etching, chemical vapor deposition, and other thin film processes There is a rigorous qualification procedure that each user must follow to get qualified to use the Cleanroom. Currently there are about 20 qualified Cleanroom users, and their names are listed under the People section. To a large extent, the daily Cleanroom activities are managed by the Users themselves. There is a Cleanroom Users Committee that works closely with the Cleanroom faculty and research support staff to oversee the daily operations of the facility. In consultation with the faculty and support staff, the Committee enforces the Cleanroom Charter and regulations, administers new users qualification procedure, assign POW duties (see next below), and participates in decisions for equipment acquisition, admission, maintenance, and repair. POW stands for "Person of the Week"; i.e., he (she) is the "detail" person who is on duty for a whole week to perform such daily tasks as checking/filling liquid nitrogen, checking/ordering chemicals, gases, cleanroom supplies, checking vacuum pumps, arranging for waste chemical pickup, etc. Every user gets to serve as a POW when his (her) term comes. Each major piece of equipment in the Cleanroom has a Master who is its primary user and up-keeper. The Master trains other users who wish to become Qualified Users for that piece of equipment. The Master is also responsible for that equipment's routine maintenance. Cleanroom Documents SEAS Clean Room Policy and Procedures (PDF: 72KB): Revised May 2008 Cleanroom Master List (doc,pdf): Updated January 2005 Cleanroom User List (html,xls,pdf): Updated January 2005 DPL, RSL, and QuLab Recipes: Updated June 02, 2004 Cleanroom Charter (PDF: 42KB): Updated June 1, 2000 Cleanroom MSDS (PDF: 5.7KB): Updated August 4, 2001 Cleanroom Exhaust Alarm Procedures: Updated November 21, 2001 Cleanroom Facilities Main Clean Room Cleanroom view #1 Cleanroom view #2 Cleanroom view #3 Cleanroom view just after construction #1 Cleanroom view just after construction #2 Gowning bay Gowning room view Lithography bay Lithography room view Mask Aligner (close-up view) EVG620 Mask Aligner: The EVG620 Mask Aligner is designed for submicron front to  backside alignment and lithography processes. All printing modes such  as soft, hard, vacuum contact and proximity are possible. The features of EVG620 mask aligner include:   1. Top and Bottom Side Splitfield Microscopes   2. Software and Process Control   3. High Precision Wedge Compensation The resolution of alignment is 0.06 um for frontside and <1 um  for front to backside. EVG620 Mask Aligner on-line test EVG620 Mask Aligner manual (PDF, 27MB) Current Master: Leidong Mao and Jian Xu Mask Aligner HTG Mask Aligner: This system is used for UV and Deep UV lithography. Photolithograhpy is at the heart of modern microelectronics fabrication. It involves transfering a pattern from a master print or "mask" onto a substrate. This is done by covering the substrate with photoresist, which is a light sensitive polymer analogous to the emulsion of a photographic plate. The mask is then aligned to any existing patterns on the substrate using the microscope and micropositioners integrated into the system. The system is capable of aligning the substrate and mask with submicron accuracy. The substrate and mask are then held together and the photoresist is exposed to UV or Deep UV light through the mask. The photoresist is then developed, leaving behind photoresist only in the pattern of the mask. The substrate and photoresist can then be baked, making the resist impervious to acids and other chemicals. The pattern of the resist can then be transfered to the substrate through chemical etching or other processes. Current Master: Joe McManis Documents: HTG Procedures (doc,pdf) SEM (Scanning electron microscope) Wet bench bay Room view Wetbench Wetbench (close-up view) Film deposition bay Room view E-beam evaporator Kurt J. Lesker EJ1800 Thin Film Deposition System: A recent addition to the cleanroom, this dual Thermal and Electron Beam Physical Vapor Deposition System has the capacity for five e-beam crucibles and four thermal boats. This capacity makes it capable of depositing quite complicated multiple layer thin films. It's turbomolecular pump enables it to achieve pressures as the low 1 X 10^-6 Torr range in less than an hour, minmizing total process times. Current Master: Jim Hyland Documents: Pete Procedures (doc,pdf) Sputterer Lesker Sputter System: This custom made system is used to deposit thin film superconductors. It has 6 magnetron sputter guns and 4 thermal evaporation stations. There are 2 DC sputtering power supplies, 2 RF sputtering power supplies, and 2 DC evaporation power supplies. When a material is sputtered, a target of the material is placed in a plasma (in our case, an argon plasma) and atoms of the plasma are accelerated at the target by a large electric field. When the plasma ions impact the target, atoms are ejected from the surface into the plasma, where they are carried away and then deposited on the substrate. The plasma and sputtered material are spatial confined by a permanent magnetic field. Sputtering general gives more uniform and reproducible results then thermal evaporation. The Lesker has intense lamps that allow substrates to be heated to temperatures approaching 1100 ^oC while materials are being deposited. The Lesker also contaings an argon ion mill that allows metal films to be atomically "sand blasted" before the deposition of new layers to ensure clean interfaces. With its two cryopumps, the Lesker can reach base pressures in the high 10^-8 Torr range. Current Master: Matthew Reese Documents: See Master Edwards Thermal Evaporator Master: Dechao Guo Documents: Edwards Procedures (doc,pdf) Benno Thermal EvaporatorInside view Master: David Routenberg Documents: None Available Varian Thermal evaporator Thermal Evaporator equipped with tilt-stage for double (multiple) angle evaporation processes such as tunnel junctions. Master: David Schuster and Luigi Frunzio Documents: User Policy (doc, pdf) Instructions (doc, pdf) Evaporation Checklist (xls, pdf) Thickness Monitor values (xls, pdf) Furnace bay Room view PECVD (Plasma Enhanced Chemical Vapor Deposition) Master: Luigi Frunzio Documents: PECVD Procedures (doc,pdf) RTA (Rapid thermal annealing): Heatpulse 210T-02 Rapid Thermal Processing System: It's maybe one of the oldest facilities in our clean room, but it still works well. Easy operation. For the annealing from 400^oC to 1000^oC in Nitrogen, forming gas and Oxygen, it's a quick choice. Current Master: DeChao Guo Documents: RTA procedure Furnace Furnace (close-up view) Characterization Equipment AFM - under construction Master: in construction Documents: Manual Optical Microscope #1 Optical Microscope #2 Ellipsometer Master: Luigi Frunzio Documents: Ellipsometer Procedures (doc,pdf) Profilerometery The DEKTAK 3030 is a surface profile measuring system. It can accurately measure vertical features with a height up to 131 microns or down to less than 100 angstroms on a wide variety of substrate surfaces. (But don't try to measure anything thicker than 45 mm.) Declared resolution goes to 1 angstrom with a full scale of 6.5 microns and 20 angstroms for 131 microns' full scale. Current Master: Xie-Wen Wang Documents: DEKTAK Procedures (doc,pdf) Copyright © 2001, Yale University, New Haven, Connecticut, USA. All rights reserved. Most cleanroom facility pictures were provided by Robert Koudelka. Site made by Takhee Lee and currently maintained by David Schuster. Comments or suggestions to Arlene A. Ciociola. Last modified: Nov. 21, 2001.