Clean room application
1.Clean Room / Aseptic Clean Room
Clean Room is a room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimize the introduction, generation, and retention of particles inside the room, and in which other relevant parameters, e.g. temperature, humidity, and pressure, are controlled as necessary. Also, the illumination, hazardous steam, and airflow direction and its velocity are also defined.
Aseptic Clean Room is a room where the Microorganisms such as bacteria or virus and biological particles are more strictly controlled.
Industrial Clean Room ICR
It is the Clean Room for industrial use, such as Precision industries, electric industries, etc.
Biological Clean Room BCR
It is the aseptic Clean Room for biological medicine or laboratories. Most of the bacteria or virus are attached to the airborne particles, which can be filtered with Filter System. However, finer bacteria can be sterilized by ultra-violet ray lamp or Hydrogen Peroxide Gas.
2.Features for Clean Room Air-conditioning
I.Temperature and humidity requirements are higher than general air-con.
The temperature requirement for general air-con is between 18°C and 26°C and the relative humidity is between 40% and 65%; while the temperature in Clean Room should be controlled between 22°C and 24°C and the humidity in it should be between 45% and 55%.
II.Constant temperature and humidity control
It is extremely temperature-sensitive for the semiconductor industry; therefore, the temperature and humidity should be controlled within ± 1°C and ± 3% in most of the Clean Room areas.
III.More air needed to balance the air pressure in Clean Room
A large amount of the chemicals and toxic gas will be required during the semiconductor production. Therefore, there will also be a huge amount of gas exhausted due to the volatile gas and exhaust gas. To maintain positive pressure inside the Clean Room, the air supply into the Clean Room is also relatively increased.
IV.Twenty-Four Seven running and monitoring on Air-con system
Part of the machines in the semiconductor production are highly sensitive to the temperature/humidity variation, such as the Stepper in Photo lithography area. A slight change of the temperature or humidity would affect the accuracy of the device. Moreover, the products like chips should be put in the environment with constant temperature and humidity. Therefore, the air-con system should be strictly monitored and managed.
V.Air pressure inside the Clean Room in the semiconductor factories
For the semiconductor factories, the air pressure in the Clean Room should be higher than the outside. Besides avoiding the influence from the temperature, humidity, and particles outside the Clean Room, it also helps extend the lifetime of the ULPA filter. However, the pressure difference should be constrained to avoid the cost increase from the increased out bounding air from Clean Room.
In order to remove the airborne particles inside the Clean Room, the air velocity shall reach the certain standard. Also, the airflow direction shall be controlled based on various levels of the Clean Room.
3.Clean Room System
The Clean Room system would produce clean air that is conformed to the specification. The clean air shall be steadily and continuously supplied to the FAB. Generally speaking, the source for producing clean air is called OUTSIDE AIR. It will undergo various of processing units in the Clean Room to produce the clean air that conforms to the specification. The following is the simplified process: The Outside air goes into the Make-up Air Unit (or MAU) to pre-filter the particle and control the temperature/humidity. After that, the air goes to the Mech. Chase. Inside the Chase, the circular air in the Clean Room and the supplying air from the MAU are mixed, and Dry Cooling Coil will cool down the air inside the Mech. Chase to the requested temperature by the Clean Room specification. Then the Fan Filter Unit (or FFU) enables the airflow cycle in the Clean Room to remove the particles and heat. Last, the air will be supplied to FAB area after filtered by the Ultra-low penetration air (or ULPA Filter).
4.Definition of Cleanliness
It means the capability for the Clean Room to effectively control the particle number in the specific room. To define the function of different types of the Clean Room, we define it based on the particles of “Specific Size” in “Specific Volume”.
Take the particle diameter above 0.5μm for example:
|Countryside||10,000,000 – 50,000,000 particles/m3|
|City||100,000,000 – 500,000,000 particles/m3|
|Indoors||100,000,000 – 1,000,000,000 particles/m3|
|ISO Class 5||control within 3,520 particles/m3|
|FS 209E Class 100||control within 3,520 particles/m3|
5.Clean Room Classifications
|ISO 2||ISO 3||ISO 4||ISO 5||ISO 6||ISO 7||ISO 8|
|ICR||Semiconductor chip manufacturer|
|Semiconductor component supplier||Front end|
|Hard Disk manufacturer|
|Precision industry manufacturer|
|BCR||Pharmaceutical manufacturer||Filling area|
|Hospital||Aseptic therapy room|
|Aseptic operation room|
|Food processing manufacturer||UHT milk|
|Fresh vegetables, fruits, boxed meal, bread|
|Animal laboratory||Aseptic animal laboratory|
The cleanroom classification standards FS 209E and ISO 14644-1 require specific particle count measurements and calculations to classify the cleanliness level of a cleanroom or clean area.
|Maximum concentration limits (particles/m3 )|
|Classification Number (N)||0.1μm||0.2μm||0.3μm||0.5μm||1.0μm||5.0μm|
|ISO Class 1||10||2||-||-||-||-|
|ISO Class 2||100||24||10||4||-||-|
|ISO Class 3||1,000||237||102||35.2||8||-|
|ISO Class 4||10,000||2,370||1,020||352||83||-|
|ISO Class 5||100,000||23,700||10,200||3,520||832||29|
|ISO Class 6||1,000,000||237,000||102,000||35,200||83,200||293|
|ISO Class 7||-||-||-||352,000||832,000||2,930|
|ISO Class 8||-||-||-||35,200,000||8,320,000||29,300|
|ISO Class 9||-||-||-||-||-||293,000|
Federal Standard 209E Airborne Particulate Cleanliness Classes
|CR Cleanliness||Diameter for Airborne Particle|
|Volume Units||Volume Units||Volume Units||Volume Units||Volume Units|
JIS B 9920
|Class||Maximum concentration limits (particles/m3 )|
Britain BS 5295
|Classs||Maximum concentration limits (particles/m3 )|
Worldwide Standard comparison
|ISO 14644-1||ISO 3||ISO 4||ISO 5||ISO 6||ISO 7||ISO 8|
|FS 209E||Class 1||Class 10||Class 100||Class 1000||Class 10000||Class 100000|
|JIS B 9920||Class 3||Class 4||Class 5||Class 6||Class 7||Class 8|
|Britain BS 5295||C||D||E/F||G/H||J||K|
|Germany VD I.2083||1C||2||3||4||5||6|
|Australia AS 1386||0.035||0.35||3.5||35||350||3500|
|France AFNOR X44101||-||-||4,000||-||4,000||4,000,000|
PIC/S GMP Guide
For the manufacture of sterile medicinal products
The “in operation” and “at rest” states should be defined for each clean room or suite of clean rooms. For the manufacture of sterile medicinal products 4 grades can be distinguished:
|Grade A||The local zone for high risk operations, e.g. filling zone, stopper bowls, open ampoules and vials, making aseptic connections. Normally such conditions are provided by a laminar air flow work station. Laminar air flow systems should provide a homogeneous air speed in a range of 0.36 – 0.54 m/s (guidance value) at the working position in open clean room applications. The maintenance of laminarity should be demonstrated and validated. A uni-directional air flow and lower velocities may be used in closed isolators and glove boxes.|
|Grade B||For aseptic preparation and filling, this is the background environment for the grade A zone.|
|Grade C||Clean areas for carrying out less critical stages in the manufacture of sterile products|
Clean rooms and clean air devices should be classified in accordance with EN ISO 14644-1. Classification should be clearly differentiated from operational process environmental monitoring. The maximum permitted airborne particle concentration for each grade is given in the following table:
|Maximum permitted number of particles/m3 equal to or greater than the tabulated size|
|At rest||In operation|
|D||3,500,000||20,000||not defined||not defined|
- For classification purposes in Grade A zones, a minimum sample volume of 1m³ should be taken per sample location.
- For Grade A the airborne particle classification is ISO 4.8 dictated by the limit for particles ≥5.0 μm.
- For Grade B (at rest) the airborne particle classification is ISO 5 for both considered particle sizes.
- For Grade C (at rest & in operation) the airborne particle classification is ISO 7 and ISO 8 respectively.
- For Grade D (at rest) the airborne particle classification is ISO 8.
- For classification purposes EN/ISO 14644-1 methodology defines both the minimum number of sample locations and the sample size based on the class limit of the largest considered particle size and the method of evaluation of the data collected.
Examples of operations to be carried out in the various grades are given in the table below :
|Grade||Examples of operations for terminally sterilised products|
|A||Filling of products, when unusually at risk|
|B||Preparation of solutions, when unusually at risk. Filling of products|
|D||Preparation of solutions and components for subsequent filling|
|Grade||Examples of operations for aseptic preparations|
|A||Aseptic preparation and filling|
|B||Preparation of solutions to be filtered|
|D||Handling of components after washing|
|Filter Class||Overall Value||Local Value|
- EPA 10 - EPA 12: Efficiency Particulate Air Filters
- HEPA 13 - HEPA 14: High Efficiency Particulate Air Filters
- ULPA 15 - ULPA 17: Ultra Low Penetration Air Filters
DIN EN 779:2012
|Minimum efficiency |
|Coarse dust filter||G1||250||50 ≤Am< 65||-||-|
|G2||250||65 ≤ Am< 80||-||-|
|G3||250||80 ≤ Am< 90||-||-|
|G4||250||90 ≤ Am||-||-|
|Medium||M5||450||-||40 ≤ Em< 60||-|
|M6||450||-||60 ≤ Em< 80||-|
|F7||450||-||80 ≤ Em< 90||35|
|F8||450||-||90 ≤ Em< 95||55|
|F9||450||-||95 ≤ Em||70|
|Filter Class||Overall Value||Local Value|
|ISO 15 E||≧95||≦5||-||--|
|ISO 20 E||≧99||≦1||-||--|
|ISO 25 E||≧99.5||≦0.5||-||--|
|ISO 30 E||≧99.90||≦0.1||-||--|
|ISO 35 H||≧99.95||≦0.05||≧99.75||≦0.25|
|ISO 40 Hd||≧99.99||≦0.01||≧99.95||≦0.05|
|ISO 45 Hd||≧99.995||≦0.005||≧99.975||≦0.025|
|ISO 50 U||≧99.999||≦0.001||≧99.995||≦0.005|
|ISO 55 U||≧99.999 5||≦0.000 5||≧99.997 5||≦0.002 5|
|ISO 60 U||≧99.999 9||≦0.000 1||≧99.999 5||≦0.000 5|
|ISO 65 U||≧99.999 95||≦0.000 05||≧99.999 75||≦0.000 25|
|ISO 70 U||≧99.999 99||≦0.000 01||≧99.999 9||≦0.000 1|
|ISO 75 U||≧99.999 995||≦0.000 005||≧99.999 9||≦0.000 1|
Please note: These charts provide approximate data regarding various filter classes for reference purposes only. Specific data applicable to an intended application must be determined at the expected face velocity.
Filter Integrity Test
(For testing HEPA) In the PAO test, a gas type of smoke will be generated by the PAO generator. After using the photometer to test the concentration on the upstream of the HEPA, a particle counter will be put at the air exhaust area to test the PAO concentration that passes through HEPA. The distance between the particle counter and HEPA will be around 25mm with testing speed at 50mm/sec. The test range includes HEPA filter and its connecting area. However, there are no related guidelines on the measurement method. Just make sure the whole HEPA covered area are tested for leakage. If there are particles over 0.03 are tested, hold the particle counter for 10 sec and then test.back and forth at the range of 100mm. Once the particles are less than 0.03, proceed the test.
PAO efficiency (%) = ( 1-particle concentration at the HEPA air exhaust area / particle concentration at the HEPA upstream area ) × 100%.
(For testing Medium Filter or Bag Filter) This is to test the integrity of the Medium Filter mainly for particle size ≧1μm. There will be the same filter indicator paper at the up/downstream of the filter. After sampling, we calculate the filter integrity based on its transparency variation. Normally the NBS method and ASHRAE method ( 52.1 —92 Standard ) are applied. In 1968年, after modification and consolidation, it is called ASHRAE Efficiency or NBS. Both represent Colorimetry.
Q1：The sampling air volume through the upstream indicator paper.
Q2：The sampling air volume through the downstream indicator paper.
O1：The opacity of the upstream indicator paper with particles on it.
O2：The opacity of the downstream indicator paper with particles on it.
Colorimetry efficiency (%)=( 1- Q1/Q2×Q2/Q1)×100%
(For testing pre-filter) This is to test the efficiency of the pre-filter on larger particles which sizes are ≧5μm.
Normally AFI method (in 1960) and ASHRAE method (52.1—92 Standard) are applied.
It is called ASHRAE Arrestance or AFI. Both represent Arrestance.
Wf：The particle quantity supplied at the upstream of the filter(g)
Wp：The weight of the particles attached on the filter(g)
Arrestance efficiency (%)=( 1- Wp/Wf)×100%
When to conduct Leak test?
- HEPA replacement
- Machine re-installation
- Regular test (at least once a year)
|Professional Technique||AIRTECH customer service engineers are all authorized by AIRTECH Japan.
We conform to the International Inspection Procedures to make sure we
offer the best technique and support.
|Strick control|| All the test equipment is under regular maintenance and calibration to
make sure our quality conforms with International standard.
|Immediate support|| We have enough stock to make sure we can deliver the spare parts within
the short period of time.
|Warranty||1.One year after we ship out.
2.If below conditions occur, there will be certain cost.
Remark 1: Testing items will vary from product type.
Remark 2: The warranty items are only applied in Taiwan.