TES-Clean Air Systems has collectively over 50 years of experience in using particle counting and other complimentary equipment to assist customers in analyzing their finished products. Depending on the distance from our offices in Fremont, Ca. and the level of testing required we offer several different levels of service, listed below.

1. Standard Testing Service- Selected When Cost and Timeliness are the Most Critical Elements of the Decision Making Process
   
2. Gold Medal Testing Services- When a PHD level Scientist With Over 30 Years of Micro-Contamination Experience is Required.

The following pages highlight several pages from a report for the Gold Medal level of service.

• Summary and Conclusions
• Velocity Conclusions Under the Mini-Environment Filters
• Differential Pressure in the Mini-Environment and in the Wafer Zone
• Particle-Per-Wafer-Pass Result
• Grap: PWP Test Summary
• Challenge Test To Quantify System Isolation From the Room

1. Air Velocity
1. The average linear velocity within the mini-environments is 104±10 feet per minute at the 95% confidence level.
2. The average linear velocity under the inner filter is 108±9 feet per minute at the 95% confidence level. This corresponds to 173 cubic feet per minute of air delivered into the wafer zone.
2. Differential Pressure (Relative To The Surrounding Room)
1. The pressurization inside the mini-environment is +0.0053 inches, water gauge.
2. The pressurization inside the wafer zone is +0.0041 inches, water gauge.


3. Airborne Particle Counts In the Prober's Wafer Zone
1. All static particle counts were within Class M-1 limits.
2. All dynamic particle counts were within Class M-1 limits.


4. Airborne Particle Counts In The Prober's Wafer Zone
1. All static particle counts were within Class M-1 limits.
2. Dynamic particle counts are within Class 1 limits (at 0.1 and 0.2 micron) and within Class 10 limits (at 0.3 and 0.5 micron).


5. Particle-Per-Wafer-Pass (Full System)
1. Three load stations were tested using 5 inch wafers.
2. Less than 0.02 particles per pass, ≥0.25 micron, were measures at the bottom. This corresponds to ≤.00015 particles-per-pass-per-centimeter-squared.
3. The top station gained less than 0.090 particles per pass, ≥0.25 micron. This corresponds to ≤ 0.0008 particles-per-pass-per-centimeter-squared.


6. Recovery Times From A Particle Event
1. The mini-environment recovers within 45 seconds.
2. The wafer zone recovers within 2.8 minutes.


7. Challenge Test (For Particles ≥0.1 Micron)
1. With a thorough outside challenge of 3X10 to the 6th power, particles per cubic foot of air (nominal), penetration averaged 3.9 particles per foot of air.
2. This corresponds to roughly 0.0001% penetration. For comparison, 0.01-0.005% is normally considered acceptable.

All surface particle measurements were performed on a KLA-Tencor Model 6220. The size threshold was set at 0.25 micron.

The bottom right load port was tested in a Class 1 surrounding environment. The other two load ports were tested in a Class 100 environment.

The definition of one wafer pass is as follows:

• SMIF pod is opened
• Wafer is removed by the robot
• Wafer is moved through the pass-through door
• Wafer is placed onto the forcer chuck
• Wafer is placed onto the pre-aligner and aligned
• Wafer is removed from pre-aligner
• Wafer is probed for 2 minutes with a simulated (no contact) 20 spot pattern
• Wafer is returned to the forcer chuck
• Wafer is picked up by the mini-environment robot
• Wafer is returned to its casette slot
• The above process continues until all 15 wafers are passed
• The SMIF pod closes

The test consisted of 20 wafer passes.

Grap: PWP Test Summary
Summary of test results for the PWP test. The average particle gain for three separate test segments is graphed at four size thresholds. The plotted points are means for 15 wafers. The error bars are 95% confidence intervals around the mean.