Approval Block. Prepared by: Signature Date Evan Parnell 08 NOV Reviewed by: Signature Date. Approved by: Signature Date

Transcription

1 ATS-ATP-3405 Page: 1 of 8 Approval Block Prepared by: Signature Date Evan Parnell 08 NOV 2013 Reviewed by: Signature Date Brian Flynn 08 NOV 2013 Approved by: Signature Date Kristal Jewell 08 NOV 2013 Historical Reference Section: Section Name Section Number (i.e., 5.2.1) Revision Affected Explanation of Change Scope 2. A Added not regarding use of facility s SOP when requested Document Control N/A B Review 1. Purpose This document provides instruction for the performance of Room Recovery and Particle Fallout test. 2. Scope This procedure shall be followed by personnel performing cleanroom certifications. Additional testing and or deviation from this SOP shall be agreed upon prior to the start of testing. Note: Facilities Standard Operating Procedures will be followed per client request.

2 ATS-ATP-3405 Page: 2 of 8 3. References 1. Institute of Environmental Sciences Contamination Control Division Recommended Practice IES-RP Testing Cleanrooms 2. International Organization for Standardization ISO Cleanrooms and associated controlled environments - Part 1: Classification of airborne particulates 3. International Organization for Standardization ISO Cleanrooms and associated controlled environments - Part 2: Specifications for testing and monitoring to prove continued compliance with ISO Material Safety Data Sheets (MSDS) located immediately outside the cleanroom. 4. Equipment and Materials Equipment: 2. Aerosol Generator Laskin nozzle compressed air operated DOP/Emery 3000 generator 3. Laser Particle Counter capable of measuring particulate relative to the classification of the room. 4. Witness Plates 5. Microscope 5. Safety 1. Wear proper cleanroom gowning attire as specified by facility SOP or as instructed by facility point of contact. 2. Avoid lifting heavy equipment. Wait for help from another employee prior to lifting any heavy equipment. 3. Avoid reaching while working on a ladder. Move the ladder to ensure proper access to your concern. Do not step on the top two rungs of a step ladder. 4. Refer to manufacturer s safety precautions and Material Safety Data Sheet (MSDS) for appropriate protective equipment and safe handling procedures when using chemicals.

3 ATS-ATP-3405 Page: 3 of 8 6. Responsibility 1. It is the responsibility of the President to maintain this document and oversee these activities. 2. It is the responsibility of the individual(s) performing this task to follow this procedure. 7. Preliminary Operations 1. Collect all materials and equipment necessary to conduct the certification. 2. Ensure all equipment is within calibration prior to the start of use. 3. Wipe down all equipment in accordance with the facility SOP or use a 70% ethanol, 30% water solution unless otherwise instructed by the facility point of contact. 8. Cleanroom Operational Phases Testing may be performed at different stages as characterized by the completeness of the cleanroom installation and operational modes as defined below. Stage 1 Stage 2 Stage 3 NOTE: As-Built-Facility: A cleanroom which is complete and operating with all services connected and functioning, following initial clean down. There is to be no process equipment or operating personnel within the facility. At-Rest-Facility: A cleanroom which is complete and operating. The room is to be fully populated with process equipment staged in a nonoperational mode. There shall be no operating personnel present. Operating Facility: A cleanroom in normal operation fully populated with functioning process equipment and operating personnel. At times it will be necessary to take exception to strict compliance with the aforementioned testing stages. Deviation or interaction among the

4 ATS-ATP-3405 Page: 4 of 8 stages may be required due to availability or operational status of the process equipment. These situations shall be identified and acknowledged as part of the contractual agreement. 9. TEST PROCEDURES AND ACCEPTANCE CRITERIA A. Room Recovery Test 1. Purpose The recovery test is performed to determine whether the cleanroom or clean zone is capable of returning to its specified cleanliness class within a finite time, after being exposed briefly to a source of airborne particulate challenge in the form of a smoke or optional aerosol. This test is not recommended for unidirectional flow rooms. 2. Apparatus A). A smoke generator or suitable alternative aerosol source B). A discrete-particle counter having a minimum sampling flow rate of 1 cfm and particle size discrimination capability of 0.5 um or smaller. 3. Procedure A). Measure the particle counts at a room air return outlet to establish the existing particle concentration level. B). Generate smoke at the air inlet to the room until a particle count at the outlet is substantially above the room s at-rest level. Turn the generator off. C). Record the particle count for a 6-second period each minute, until the cleanliness level at the outlet is restored to the original condition. Record this decay time.

5 ATS-ATP-3405 Page: 5 of Acceptance Recovery times are a function of airflow velocity, room volume, and the distribution pattern of the HEPA filtered air supply. Acceptable recovery times are to be determined by each facility. The recovery time may be recorded for information only. B. 1. Purpose Results of the particle fallout count indicate the concentration of large airborne particle that are not detected effectively using discrete-particle counters. Particle fallout counts are obtained by allowing a small test surface (witness plate) to collect natural particles (no artificial challenge) that settle out in the cleanroom environment. The particles on the witness plate are counted with a surface particle detection instrument, and a particle deposition rate is determined. 2. Apparatus Witness plate materials should match the type of surface particle detection equipment to be used. Suggested combinations of suitable witness plates and particle detection instruments are: Surface particle detection instrument Microscope, manual or automatic Automatic silicon wafer surface particle detector Suitable witness plate Blank silicon wafers Microscope slides Membrane filters Glass photomask substrates Blank silicon wafers In choosing the method or instrument to be used for this test, consideration should be given to its ability to detect particles in the designated size range appropriate to the specific product being manufactured. The time required

6 ATS-ATP-3405 Page: 6 of 8 for sample analysis and the subjectivity of the procedure should also be considered. Microscopic detection equipment should be set up to detect a minimum particle size of 5 um on the witness plate material selected. The minimum detection limit of silicon-wafer surface-particle detectors is dependent on the model chose, typically in the range of 0.1 to 2 um. A suitable calibration procedure should be established to assure the user that reasonably accurate results are being obtained at each test. 3. Procedure A) Verify that all components of the cleanroom system that contribute to its operation are complete and functioning in accordance with the requirements of the type of cleanroom and the operational mode under test. B) Establish a test point grid at the working level that will satisfy user requirements and be compatible with the type and operational mode of the cleanroom. C) Provide a method of identifying each witness plate. D) Determine and record the background level (before) count on each witness plate, in terms of the average number of particles per square centimeter. average particles = cm 2 total particles on witness plate witness plate area in cm2 E) Provide a sufficient quantity of witness plates to measure the environment and additional witness plates to serves as controls. A minimum of three witness plates should be used as controls. The controls should be handled identically to the other witness plates except that they should not be exposed to the environment.

7 ATS-ATP-3405 Page: 7 of 8 4. Reporting F) Place all witness plates (including the controls) in a suitable, clean container for transportation to the cleanroom test sites. G) Place the witness plate on a surface or support fixture which allows the collection surface to be exposed horizontally at the test point location. Care should be taken to avoid atypical charge potential of the witness plate. Uncover the witness plate immediately before placing it on the support surface. H) Briefly uncover the controls, Place on a support surface, and immediately reinstall the cover and return for particle counting. This count will provide a representation of particles added due to handling. I) Leave the witness plates exposed to the environment for a minimum of 4 hours, or a s long as is necessary to obtain a statistically valid sample, depending on the type of cleanroom, mode of operation, and the test apparatus used. The environmental exposure time should be adequate tot obtain particle samples that satisfy user requirements. J) Take a minimum of three simultaneous particle fallout measurements at each test location. A) Calculate and repot the particle deposition rate as follows: 1) Determine the number of particles per square centimeter added on each of the control witness plates, using the following formula: AC-BC = Paticles/cm2 added to control ACW AC = After Count BC = Before Count

8 ATS-ATP-3405 Page: 8 of 8 5. Acceptance ACW = Area of control witness plate in square centimeters 2) Divide the net particles per square centimeter added by the number of hours the test witness plates wee exposed to the environment. This yields a normalized particle deposition rate in terms of particles per square centimeter per hour. B) Record all individual measurements. Average the readings (three or more) to obtain a mean particle count for each grid location. Record the mean counts on a grid map to show particle fallout levels as a function of location within the cleanroom. Acceptable particle deposition rates should be established by the facility.