For Work Safety at the Vicinity of Overhead Transporta8on
Vehicle Systems
Shigehito Ibuka Tokyo Electron Limited
May 19, 2011 @IHTESH2011, Arizona, USA
Outlines
• Pictures of “Overhead Transporta8on Vehicles” • Background • Case Study of some Incidents
• SEMI Workshop – Risk – Engineering Control – Administra8ve Control
– Summary
• Huge semiconductor fab • High produc5vity demand
Background
Unmanned transportation vehicle system (UTV), Especially, Overhead transportation vehicle system (OHV / OHT)
Automation
• High speed • More than 100 vehicles in a fab
Start-‐up or maintenance work on semiconductor manufacturing tools
• Collision • Near-miss How to prevent?
• When a person climbed the ladder to do wiring work on the system carrier stage, he turned to face the system and was struck on the shoulder by an OHV running from his right.
Case Study: Ver8cal Furnace
TEL system
Sub-frame
Non-TEL system
OHT (overhead hoist transport) collision 1 collision 2
OHT was stopped about 10 m away from the system, but suddenly started moving.
• The sub-frame was pushed and hit the worker opposite the collision in the head. The injured person got his head caught between the system behind him and the sub-frame.
• Fortunately, the injured person was wearing a helmet and did not fall off the ladder, so he avoided injury.
• At mounting a sub-frame on top of a system, an OHV suddenly moved and collided with the sub frame that was being mounted.
Case Study: Wet Cleaning System
TEL System
Other System
T Block 2
CSB
OHV
A ladder
• A person had known that a ladder set in front of the system was a hindrance to the work and temporarily moved the ladder to the CSB side.
• Immediately after moving the ladder, he determined that his help was needed to support other work and he left the area without confirming appropriate position of the ladder.
• At that point, the OHV struck the ladder, causing the OHT cover to break.
Case Study: Coater and Developer
Position of Semiconductor Manufacturing Equipment and OHT (The numerical value is one example. )
OHT OHT
3500mm(SEMI E72 Max)
2800mm
2700~3000mm
1500mm/sec
3000mm/sec
FOUP
OHT OHT
Potential Hazard and Risk Estimation
Risk Estimation Severity:1, Likelihood:C ---> Risk Rank:Ⅳ(High)
OHT OHT
Risk Estimation Severity:1, Likelihood:C ---> Risk Rank:Ⅳ(High)
Potential Hazard and Risk Estimation
OHT OHT
Risk Estimation Severity:1, Likelihood:C ----> Risk Rank:Ⅳ(High)
Potential Hazard and Risk Estimation
Risk Estimation Severity:2, Likelihood:C ----> Risk Rank:Ⅲ(Medium)
OHT OHT
Potential Hazard and Risk Estimation
OHT OHT
Risk Estimation Severity:3, Likelihood:C ----> Risk Rank:Ⅱ(Low)
Potential Hazard and Risk Estimation
Position tracking by
sensor
OHT OHT
Prevention interlock
between worker and FOUP
I/F based on SEMI E84
Interlock between SME
and OHT
Collision prevention means with
OHT
Partition or Defense
equipment
Examples of Engineering Controls
An Example of Engineering Controls
Obstacle sensor function
Obstacle Sensor Detection Area
*Obstacle Sensor Detection Area (straight)
detection1 detection2
stop Slowdown
1. Conduct Job Hazard Analysis (JHA) {Work Risk Assessment or Pre-task Planning (PTP)} Refer to SEMI S21
2. Request the user of a fab to have the vehicle stop before entry in the OHT area
3. Share hazard or risk information among personnel of multiple suppliers and contractors to work in the adjacent area simultaneously Hold "Safety Supervisors’ Communication Council" among the
user, multiple suppliers and contractors --- Refer to SEMI S24 Conduct joint “Safety patrol” --- Refer to SEMI S24
4. Conduct safety training for all workers Refer to SEMI S19
Examples of Administrative Controls
An Example of Administrative Controls
Elevated W
ork
Stop by front sensor
Detection Board Board Setting
Comments / Suggestions after the Workshop • Shared what are issues for tool & vehicle suppliers • To plan how to share the issues with Asian IDMs and how to
improve work environment in a fab • More cases and experiences to be shared • To consider how to utilize a protection board set on the OHV
rail protect • Importance of SEMI S17 understood • Torque of OHV to be recognized among users & tool suppliers • To consider engineering controls such as sensor or some
ideas to utilized by public train systems • To specify roles of users & suppliers and share them among
concerned entities • To consider hooking points on the OHV run-yard • To hold similar concept workshops globally