1. Presented by
R.K.Shahana
11PN08

2. CONTENTS
 Introduction
 Features
 Cleanroom standards
 Stages of Cleanroom
 Different stages of cleanliness
 Cleanroom subsystems

3. INTRODUCTION
 Used in scientific research
 Has low level of environmental pollutants and controlled
contamination
 Later for lithography
 Cleanroom ensures contamination free processing under stable
environment

4. FEATURES
 Over pressure
 Filtered air(99.9995% at 0.15 um particle size)
 Heating/cooling/humidification
 Laminar air flow
 Materials compatibility
 Mechanical and electrical interference minimization
 Working procedures

5. CLASSIFICATION
Based on particle count
Federer standard(particles per cubic foot)
ISO standard(particles per cubic meter)
 The first Federal standard 209 was produced in the year
1963.
 Measurement of particles of ≥0.5 µm by means of optical
particle counters was defined.

6. FEDERER STANDARD

7. ISO STANDARD

8. Cond....

9. DIFFERENT STAGES
 As built
 Static
 Operational

10. STAGES OF CLEANLINESS
 Entrance-footwear is changed into cleanroom shoes and
hair is covered
 A mouthpiece, a second layer of headgear and cleanroom
boots to cover the shoes
 Finally gloves are put on

11. CLEANROOM SUBSYSTEMS
 Construction
 Air
 DI water
 Gas systes

12. CONSTRUCTION
 Scaling
 Walls
 Floor

13. AIR
 Air filtered from coarse objects
 Cooling coils and heaters for temperature stabilization
 Final filter HEPA and ULPA installed in cleanroom
 Air velocity 0.35-0.45 m/s
 Air circulation 50-500 times/s

14. DI WATER
 Major sub system-enormous water consumption
 Water is treated in many ways;
-Continuous DI water circulation in cleanroom
-RO
-UV treatment

15. GAS SYSTEM
• Requirements
->specifications
->leak rates
->gas impurity test
• Four purity classes of Nitrogen
->process nitrogen
->dry nitrogen
->pistol nitrogen
->pump nitrogen

16. REFERENCES
 Introduction to microlithography-Sami Franscilla