clean room opportunities

Braden Crowe, Josh Lee, Amorette Getty

Institute for Energy Efficiency and LabRATS

University of California, Santa Barbara

Clean Rooms: A Great Opportunity for High Performance Conservation

LabRATSLaboratory

Research and Technical Staff

Outline

Cleanroom Overview What makes a cleanroom? Cleanroom types UCSB Case Study: UCSB Nanofab

Strategies for Conservation Behavioral, Equipment, and Building Systems Labs21 Benchmarking Tool

Behavioral initiatives Equipment Building Design

What is a clean room?

“…a room in which the concentration of airborne particles is controlled...”

William Whyte, 2001

50x more energy per square foot than an office or residential building

Cleanrooms: Classes and Particles

ISO 14644-1 Cleanroom Standards

Class

maximum particles/m³FED STD 209Eequivalent≥0.1 µm ≥0.2

µm≥0.3 µm ≥0.5 µm ≥1 µm ≥5 µm

ISO 1 10 2

ISO 2 100 24 10 4

ISO 3 1,000 237 102 35 8 Class 1

ISO 4 10,000 2,370 1,020 352 83 Class 10

ISO 5 100,000 23,700 10,200 3,520 832 29 Class 100

ISO 6 1,000,000 237,000 102,00

0 35,200 8,320 293 Class 1000

ISO 7 352,000 83,200 2,930 Class 10,000

ISO 8 3,520,000 832,000 29,300 Class 100,000

ISO 9 35,200,000 8,320,000 293,00

0 Room air

http://en.wikipedia.org/wiki/ISO_14644-1

Contrasts: Biotech/pharmaceutical and Semiconductor Cleanrooms

Bio/Pharma Semiconductor

Typical Specs Class 100 – 100,000 Class 1 - 1000

Contamination•Bacterial•Cross-contamination

•Physical•Electrical

Process Needs•DI water (bacteria free)•Disposable materials

•High plug load equipment•Acid and solvent wet processing

Typical Equipment

•Bioreactors•Fermentors•Incubators•Analytical equipment

•Lithography•Thin-film deposition•Characterization•Dry etching

UCSB’s Engineering Science Building (ESB)

Electricity and Lighting

Efficient T8 fluoresent lighting

Daylighting

Occupancy Sensors

Zone control

Building size

90,000 ft2

60% lab space

190 office occupants

Ventilation System

Offices: Ventilation, Heating Panels

2nd and 3rd floor labs: • 100% Fresh Air, 68-73° F

• Variable Air Volume, 6-10 ACH

• VAV Fume Hoods, 100 ft/min face velocity

UCSB Nanofabrication Facility

“ESB Cleanroom” Largest of 5 cleanrooms on the UCSB

campus

Nanofab, Semiconductor processing InP, GaAs, GaN, SiC, Si, and novel materials

Equipment and Capabilities Lithography Thin film deposition Dry Etching Thin film characterization Wet Etch Anneal Wafer Bonding

Chase 2

Chase 3

Chase 4

Chase 5

Chase 6

Chase 7

Gowning Room

Chase 1

Cla

ss 10

00

Cla

ss 10

0

ESB Cleanroom Profile

500 Registered users (300 UCSB academic)

12,700 ft2 cleanroom space

16 Class 10 laminar flow wet benches

100 individual processing setups

50 vacuum pumps

HVAC System

Recirculate via HEPA Fan Filter Units (FFUs)

Exhaust – 2 Strobic fans

Upcoming Retrofit: Third exhaust stack

planned to accommodate incoming

equipment

Auxiliary Cleanroom Systems

Air Supply and Exhaust

Compressed Dry Air

Process Vacuum

DI Water systems

Toxic Gas Monitoring

Process Chilled Water

Specialty Gas Cabinets

High purity process piping

Solvent Collection system

2 55-gallon drums

pH neutralization system

NaOH & H2SO4

Improvement Plan

3 Target Areas Behavioral

Building-Specific Sustainability guide Fume hood sash labeling and monitoring Lecture: “Intro to Lab Buildings, Cleanrooms, and Sustainable

Research” DI Sample Rinse Procedures

Equipment Inventory all equipment setups, all vacuum pumps Measure plug loads and identify more energy efficient models Identify under-utilized setups, arrange to shut down when not needed

Building wide systems Optimize and Balance Air-handling Scrutinize exhaust requirements Sub-metering cleanroom electrical for better benchmarking

Labs21 Benchmarking

Cleanroom Self-Benchmarking Guide

Best Practice Summaries

Case Studies

Programming Guide for New Construction

Laboratory Equipment Wiki

Improvement Plan


Building-Specific Sustainability guide Fume hood sash labeling and monitoring Lecture: “Intro to Lab Buildings, Cleanrooms, and Sustainable

Research” DI Sample Rinse Procedures



DI water supply: Eliminate Waste

4" Si Wafer (with a SiNx film on top) soaked in Piranha solution (H2SO4:H2O2, 3:1) at 80 C for 5 minutes

Rinse Test #1 (Rinse

Time=0 s)*Rinse Test #2 (Rinse



Time=60 s)*

Resistivity Before Wafer

Rinse (MWcm)1.89 1.901 1.96 1.901

Resistivity After 1st

Wafer Rinse (MWcm)

0.001 0.001 0.012 0.005

Dumping Water

Yes Yes Yes No

Resistivity After 2nd

Wafer Rinse (MWcm)

0.02 0.051 1.498 0.029

Dumping Water

Yes Yes Yes No

Resistivity After 3rd

Wafer Rinse (MWcm)

0.05 1.551 1.904 0.055

Dumping Water

Yes Yes Yes No

Resistivity After 4th

Wafer Rinse (MWcm)

1.855 1.894 1.954 0.141

3 rinse-dump cycles

Continuous overflow

for 4 minutesCourtesy of Ning Cao, PhD, UCSB Nanofab

Improvement Plan


Building-Specific Sustainability guide Fume hood sash labeling and monitoring Lecture to researchers: “Intro to Lab Buildings, Cleanrooms, and

Sustainable Research” DI Sample Rinse Procedures



Power Down Unused Equipment

Identify rarely-used setups with high idle power Examine electronic signups and log books

Potential roadblocks: Stability issues (i.e. furnace temperatures) Time/inconvenience to power up Political Resistance

Efficient Alternatives for Equipment

Existing equipment: Repair when necessary, or… Replace with more efficient models

New equipment Always cost effective to purchase efficient

models Payback times <2 years At UCSB, rebates available

Check the Labs21 Lab Equipment Wiki

Case Study: Vacuum pumps

Cost: $3-20k ($50k max) Rebuilds every 1-10 years, at 30% of initial cost Power consumption 900-14,000 kWh/year

Feasible to replace rather than rebuild/repair? For a $3k pump replaced with a 70% more efficient model

Payback ~5 years At UCSB

Savings go to Facilities Cost would be to lab

For all new purchases at UCSB Efficient models cost effective Rebate: $2.10/W saved compared to standard model.

Improvement Plan


Building-Specific Sustainability guide Fume hood sash labeling and monitoring Lecture to researchers: “Intro to Lab Buildings, Cleanrooms, and

Sustainable Research” DI Sample Rinse Procedures



Real-time monitoring in ESB Cleanroom

Currently monitored: Temperature, Humidity in each bay DI Water: flow rate, resistivity, supply pressure LN2 tank level Room ambient pressure, general and toxic exhaust pressures Boiler temperature and pressure Chilled water supply temperatures and pressures House vacuum pressure Air supply volume

NOT monitored: Particle counts Power usage

“You can’t manage what you don’t monitor.”

Building systems – Air Supply

Make-up Air Humidity, Temperature control 1st-tier HEPA filtration Benchmark Average of 0.75 W/cfm

Recirculation Fan Filter Units, Ductwork, or Pressurized Plenum 2nd-tier HEPA filtration Laminar Flow Benchmark Average of 0.43-0.63 W/cfm

20-150 fpm at filter face 10% decrease in fan speed is a 27% decrease in power

ESB Cleanroom: No monitoring or control of FFUs

Demand-Based Filtration

1-2 shift labs: Dial back air supply when

the lab is empty. No accumulation of

particulates has been observed.

24 hour operation: Real-time feedback

required

Particle-based or occupancy-based feedback into fan filter units.

Building systems - Exhaust

Laboratory exhaust required for: Heat for air-cooled equipment Removal of effluent

solvent/acid fumes ozone from UV lamps process gasses

Sufficient air changes/hour (ACH) for occupant comfort

30% of cleanroom equipment requires exhaust

Scrutinizing equipment exhaust rates can lead to significant energy savings Must address safety trade-off in many cases

ESB Case Study: Specialty Gas Cabinet Room Exhaust 2 Gas Cabinet Rooms 6500 cfm continuous flow

~20 cfm/sqft Cleanroom exhaust system at capacity

Upcoming addition of 3rd exhaust stack Opportunity: incorporate efficiency features Decrease spec’d exhaust rate, install smaller

fan Occupancy and Gas sensors

Less exhaust when room is empty and no leaks are detected

Next Step/Directions

Continue User Outreach Efforts

Measure equipment plug loads

Advise on choices for new equipment

Get in the loop when new purchases are being made

Add data to Labs21 Lab Equipment Wiki

Real-time particle or occupancy-based filtration

Measure and Control FFU Speeds

Gas Cabinet Room Retrofit

Roadblocks and Solutions

Priorities of Lab Staff and Researchers #1: Research Success #2: Safety #3: Sustainability/Energy Efficiency

Consider instead the “Laboratory Triple Bottom Line” Success, Safety, and Sustainability Leverage synergies:

Particle counters detect contaminants and feedback to air handling

Better fumehood sash behavior is safer and more energy efficient. Proper DI rinse procedures more effective and use less water.

Conclusions

Behavioral changes easiest, but least impactful Most feasible for low budget projects

Building-wide changes high-impact, high expense Take an initially broad approach, then refined to high-potential

target projects

In a University setting, efficiency savings alone are insufficient motivation for retrofits and equipment replacement. For new equipment purchases and planned retrofits, investments

for efficiency pay off quickly. Different for corporate labs:

Genentech: $1.7 million project, 1.7 year payback time Applied Materials: $200,000 project, 2.7 year payback time

Case studies from www.hightech.lbl.gov

Questions?

Gas Cabinets – Supplemental Material

Rooms containing Room A: Cl2, BCl3, NH3, Room B: H2, SiH4, CH4, Forming gas 10% H2/

90% N2

Current throughput: Separate air handler supplies unconditioned air ~20 cfm per square foot Do we have something to compare 20 cfm to? Served by

clean room opportunities

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