Presentation 4 wafer cleaning

Presentation 4 wafer cleaning - SEMICONDUCTOR MANUFACTURING...

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SEMICONDUCTOR MANUFACTURING - CLEAN ROOMS, WAFER CLEANING AND GETTERING Modern IC factories employ a three tiered approach to controlling unwanted • Modern IC factories employ a three tiered approach to controlling unwanted impurities: 1. clean factories 2. wafer cleaning 3. gettering Year of Production 1998 2000 2002 2004 2007 2010 2013 2016 2018 e gy N l i ) 50 80 30 0 5 5 2 2 8 Technology N ode (half pitch) 250 nm 180 nm 130 nm 90 nm 65 nm 45 nm 32 nm 22 nm 18 nm MPU Printed Gate Length 100 nm 70 nm 53 nm 35 nm 25 nm 18 nm 13 nm 10 nm DRAM Bits/Chip (Sampling) 256M 512M 1G 4G 16G 32G 64G 128G 128G MPU Transistors/Chip (x10 6 ) 550 1100 2200 4400 8800 14,000 Critical Defec t Size 125 nm 90 nm 90 nm 90 nm 90 nm 90 nm 65 nm 45 nm 45 nm Starting Wafer Particles (cm -2 ) <0.35 <0.18 <0.09 <0.09 <0.05 <0.05 Starting Wafer Total Bulk Fe (cm -3 ) 3x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 Metal Atoms on Wafer Surface 5x10 9 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 1x10 10 After Cleaning (cm -2 ) Particles on Wafe r Surface After Cleaning (#/wafer) 75 80 86 195 106 168 Photoresist Au Cu Fe Particles Na N, P • Contaminants may consist of particles, organic films (photoresist), 2003 ITRS Front End processes Silicon Wafer SiO 2 or other thin films Interconnect Metal heavy metals or alkali ions.
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Examples of Contaminants Particulates Activity Particles released per minute Seated 100K a t cu ates Silicon dusts (wafer, moving parts from equipment or instrument) Moving, 2miles/hr 5M oving, 3.5 .5M Air dust (organic mineral, metallic) Skin flakes or hair Photoresist chunks Bacteria or fungi Moving, 3.5 miles/hr 7.5M Moving, 5 miles/hr 10M acte a o u g Pelles Film hotoresist seams “Bunny Suite” • coverall jumpsuit Photoresist seams Solvent residual Developer residual Oil or grease films • hood • mask • goggles Portions of films that break loose condensed vapor of gases • booties •g loves can become particles
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Cleanroom Cleanroom is a room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimize the introduction, generation, and retention of particles inside the room and in which other relevant parameters, e.g. temperature, humidity, and pressure, are ontrolled as necessary controlled as necessary.
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Presentation 4 wafer cleaning - SEMICONDUCTOR MANUFACTURING...

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