Lecture_4-Wet_Processing_clean

Lecture_4-Wet_Processing_clean - Lecture 4 Wet Processing...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Wet Processing and Wafer Clean Lecture 4
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IH2655 Spring 2008 Mikael Östling KTH Modern IC factories employ a three tiered approach to controlling unwanted impurities: 1. clean factories 2. wafer cleaning 3. gettering
Background image of page 2
IH2655 Spring 2008 Mikael Östling KTH Three tiered approach 9 clean room 9 wafer cleaning 9 gettering “Dirt is a natural part of life.”
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IH2655 Spring 2008 Mikael Östling KTH Factory environment is cleaned by: 9 HEPA filters and recirculation for the air. 9 “Bunny suits” for workers. 9 Filtration of chemicals and gases. 9 Manufacturing protocols. HEPA: High Efficiency Particulate Air
Background image of page 4
IH2655 Spring 2008 Mikael Östling KTH 1. Air cleaning From Intel Museum
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IH2655 Spring 2008 Mikael Östling KTH Class X In each cubic foot of air, there are less than X total particles greater than 0.5 μ m in size.
Background image of page 6
IH2655 Spring 2008 Mikael Östling KTH
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IH2655 Spring 2008 Mikael Östling KTH HEPA Filter Exhaust Thin Porous Sheets (ultrafine glass fibers): Large particles are trapped by filters and small particles are adsorbed by electrostatics Recirculation 20 22 ° C 40 46 RH
Background image of page 8
IH2655 Spring 2008 Mikael Östling KTH Since all the components and interconnects in ICs are rather tiny, contaminations by dust and metals during manufacturing likely lead to malfunctioning devices or circuits through short or open defects. About 75% of the yield loss in a modern silicon IC manufacturing plant is due directly to defects caused by particles on the wafer. Example 1. For an IC manufacturing plant, its output is 1000 wafer/week × 100 chip/wafer and the chip price is $50/chip. The plant is breakeven if the product yield is 50 . In order for an annual profit of $10,000,000, the product yield should increase by Increasing the product yield by 3.8%, gives rise to the annual profit of 10 million dollars! Annual throughput =Annual expense =1000 × 100 × 52 × $50 =$260,000,000 % 8 . 3 52 50 $ 100 1000 10 1 $ 7 = × × × ×
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IH2655 Spring 2008 Mikael Östling KTH Unwanted impurities must be kept below the ppm or ppb range Critical (Fatal) Defect (Particle) Size = 1/2 Minimum Feature Size 22 2016 14 32 45 65 Minimum Feature Size nm 2020 2013 2010 2007 ITRS Feature Year Particle Organics: Oil,Photoresist Metal/Alkali ions Native oxide Particle Organics: Oil,Photoresist Metal/Alkali ions Native oxide Three tiered approach 9 clean room 9 wafer cleaning 9 gettering
Background image of page 10
IH2655 Spring 2008 Mikael Östling KTH Contaminants may consist of particles, organic films (photoresist), heavy metals or alkali ions.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
IH2655 Spring 2008 Mikael Östling KTH Harm of the unwanted impurity Example 2. Effects of alkali ions on MOS threshold voltage ox M ox f A s f FB th C qQ C qN V V + Φ + Φ + = ) 2 ( 2 2 ε If t ox 10 nm, when Q M 6.5 × 10 11 cm -2 10 ppm), Δ V th 0.3 V Example 3. Request of MOS DRAM refresh time on trap density N t Typically, σ = 10 -15 cm 2 , v th = 10 -7 cm/s So τ R 100 μ s requires N t 10 12 cm -3 =0.02 ppb !!
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/09/2009 for the course EE 300 taught by Professor Y during the Spring '09 term at CUNY City.

Page1 / 44

Lecture_4-Wet_Processing_clean - Lecture 4 Wet Processing...

This preview shows document pages 1 - 13. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online