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Prevention Maintenance Protection and Hazards Exposure Control of Thermal Type Local Scrubber MAT

*Hsiang-Ming (Albu) Tsou, Presenter (albu_tsou@umc.com) United Microelectronic Corp., Rui-Xiang Cheng, Measuring Staff Industrial Technology Research Institute

SESHA 33rd / SIA IHTESH Conference, Scottsdale, AZ, May 16~20, 2011

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Contents

•  Introduction •  MAT Local Scrubber (L/S) Instruction •  Background

•  Method •  To review the whole current PM procedure •  To identify hazards escaped •  To survey an improvement program for the PM

protection and hazards exposure control •  To confirm the effectiveness

•  Results/Discussion •  Conclusion

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Introduction- MAT Local Scrubber (L/S)

•  It is a thermal/wet type L/S •  The main “exhaust treatment equipments” in the study

Fab •  High temperature oxidization

(approx. 800℃) plus water scrubber treatment system

•  For exhaust treatment of CVD, PVD, Diffusion Module in Fab

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Introduction- Background

•  Prevention maintenance (PM) is one of the main causes of odor and contaminants in Fab

•  Staffs complain the nuisance odor during L/S PM •  Unknown contaminants may cause SH risk and production

(wafer) issues •  It is better to take prevention of odor in advance than to

deal with it upon it occurs. •  Purpose

•  To presents a method of identifying the main reason for causing odor during MAT L/S PM

•  To understand the environment air quality during L/S PM •  To control hazards exposure risk and reduce bad influences

over the PM task

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Truss

Fab

subfab

Etching

Fab Pollution

MAU

Stack

NH3 、 HF 、 F2 、 O3

Stack pollution

Southwest~ Northwest wind

Wind dir.237°～ 300°

Avg. wind v. 1.1~ 3.0m/s

Diffusion

boldface: health risk

italic: odor issue

underline: process harm

Photo Thin Film

HF

HCl、SiF4、C2H5OH

HDA、WCA、PCA

SAA

PM escape

IPA、HCl、SiF4

MEA、PEL、GNS

IMP

As

T-BOX (Fab 2A subFab)

Leakage

PGMEA NH3

H2SO4

RWS TRP-D1

Introduction- Background

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Method-To review the whole current PM procedure

•  To survey the current (before improvement) PM procedure and collect relevant information: production process, raw material, PM chemicals, PM period, SOP, byproduct

•  The basic approach is performing Job Safety Observation (JSO)

•  Re-JSO after improvement

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Method-To identify hazards escaped

•  Real-time measuring during the PM processes •  To measure the contaminant sources

(disassembling, disconnecting, wiping, cleaning) and breathing zone of operator

•  Measuring instrument: MDA TLD-1 (MDA Scientific, Zellweger Company) •  Portable toxic gas detector •  Low chemical interference

(exclusive Chemcassette, Chemkey)

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Results/Discussion •  Production tool, Process, L/S information

•  Current procedure for L/S PM (before improvement) •  Condition for PM: Gauge pressure from negative to

positive •  Brief introduction of PM: 1.  Shut down the L/S and switch to another backup 2.  Wait the temperature of thermal chamber down to room temp. 3.  Open the case and disconnect the pipes 4.  Disassemble the wet and the thermal chamber, and remove nearby 5.  Wipe powder contaminants and clean chamber, pipes, parts, and main

body of L/S 6.  Assemble and recover

Tool L/S L/S Model

Process Process Chem. PM Chem.

PM Cycle

PM time

Anti-odor

byproduct

SAA-A4

SAA-L4

MAT 501B

SAA (PETEOS)

Process: TEOS Clean: C3F8,O2,He

DI Q/or failure

2~3hr Keep exhaust

Acid liq, powder (SiF4,HF,SiH4)

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Results/Discussion •  JSO finding and measuring result (before improvement)

•  AMC HF(g) (MA*) had been produced and escaped during PM •  Peak concentration was up to 2.9ppm, and approx. TLV-TWA(8)* •  Operators did not wear inhalation PPE •  Did not keep local exhaust at key risky PM steps

Note: * SEMI F21-95, F21-112; OSHA PEL, TWN OEL, NIOSH REL TWA=3ppm; OTV>=0.042ppm

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Results/Discussion

•  Improvement program for L/S PM protection and hazards exposure control

•  To compel operators to wear PPE during L/S PM task

•  To demand operators to keep local exhaust

•  To develop an Isolation Hood* to increase the local exhaust and diminish hazards escaping

Note: *Named as “Gas Separating Mask” in the abstract

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Results/Discussion

•  Improvement program for L/S PM protection and hazards exposure control (contd.)

•  To modify the PM procedure with improvement program •  To compile into SOP and PM checklist

Note: *Named as “Gas Separating Mask” in the abstract

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Results/Discussion •  To confirm the effectiveness (after improvement)

•  No HF(g) had been measured around the L/S environment during PM by setting an “Isolation Hood” over the L/S with “local exhaust”

•  The peak concentration of escaped HF(g) had been diminished from 2.9ppm to ND(0.6ppm)*, the improvement (reduction) rate was over 79.3%(as HF(g))

•  Complying with the modified SOP, the re-JSO result was good

Note: *ND means under the LDL of the instrument MDA TLD1, that is 0.6ppm

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Conclusion •  A method is proposed for understanding the air

quality, identifying the main reason for causing odor during thermal/wet type L/S PM and reducing its influence

•  With the utilization of the “Isolation Hood with local exhaust”, a management director can protect operators health and reduce hazards exposure risk. (about 79.3% as HF(g) in this case study)

•  In accordance with the modified SOP, operators can perform thermal/wet type L/S PM tasks more safe and efficient

•  This method is included but not limited to thermal/wet type L/S MAT

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Thanks for your attention!