FTIR Detection of Outgassing Chemicals: Instantaneous and Comprehensive Identification and Quantitation John C. Hulteen, Ph.D. Environmental Specialist 3M St. Paul, MN DISKCON 2000 San Jose, CA September 19, 2000
Airborne Molecular Contaminants (AMC) Sources: plastics, tapes, adhesives, pumps, process chemicals, solvents, people, etc. Effects: corrosion, hazing, molecular contamination, adhesion, etc. Major Issue : How do you quantitate and speciate molecular compounds that are outgassed from disk drive materials in a timely manner.
An Innovative New Alternative to Existing Technologies. Detection of acids, bases, volatiles and semi-volatiles simultaneously. Quantitation and identification of compounds. Fast collection and analysis time - manufacturing requirement. Low detection limits as required by the microelectronics industry. Rugged method and instrumentation for plant application. Simple equipment maintenance and operation.
3M Proprietary FTIR Static Headspace (SHS) temperature controller infrared source and detector heated 4.5 L chamber sample drawer
FTIR Static Headspace (SHS): Outgassing Profile FTIR Static HS Gas Cell IR Source Total Cumulative Outgassing vs Time IR Detector Absorbance Units SAMPLE FITR Spectra ng/cm 2 Time
FTIR Static Headspace (SHS): Outgassing Profile FTIR Static HS Gas Cell Total Cumulative Outgassing vs Time Absorbance Units SAMPLE FITR Spectra ng/cm 2 Time
FTIR Static Headspace (SHS): Outgassing Profile FTIR Static HS Gas Cell Total Cumulative Outgassing vs Time Absorbance Units SAMPLE FITR Spectra ng/cm 2 Time
FTIR Static Headspace (SHS): Outgassing Profile FTIR Static HS Gas Cell Total Cumulative Outgassing vs Time Absorbance Units SAMPLE FITR Spectra ng/cm 2 Time
FTIR Static Headspace (SHS): Outgassing Profile FTIR Static HS Gas Cell Total Cumulative Outgassing vs Time Absorbance Units SAMPLE FITR Spectra ng/cm 2 Time
Determination of Extent of Outgassing in SHS FTIR 9 8 ppm v of acrylate in cell 7 6 5 4 3 2 1 0 TOTAL OUTGASSING OF THE SATURATED ACRYLATE HEADSPACE WAS REACHED AT THIS TEMPERATURE OR Purge with N 2 TOTAL OUTGASSING 0 10 20 30 40 50 60 70 80 Time (min) Stop N 2 purge and reseal cell Label Tape at 85 C
The Basic Principle of Infrared Spectroscopy Formic Acid O C 1775 cm -1 H O H O 638 cm -1 C H O H 1105 cm-1 C H O H O Absorbance 2945 cm -1 H O C O H Energy (wavenumbers cm -1 ) Fingerprint Region
FTIR Detection of Acids Collection Time < 2 minutes hydrofluoric acid (HF) 3 ppm v Absorbance acrylic acid 16 ppm v hydrochloric acid (HCl) 29 ppm v acetic acid 11 ppm v Energy (wavenumbers cm -1 )
Example of Outgassing Acids in Tape Products Tape Sample A Formic acid detected in outgas after 2 minutes. Formic Acid Standard Fully outgassed at 570 ng/cm 2 or 41 ppm w after 120 minutes. FTIR outgassing spectra of a tape sample and standard at 85 o C Cummulative Outgassing Concentration (ng/cm2) 600 500 400 300 200 100 0 0:00 0:28 0:57 1:26 1:55 2:24 Time (hr:min)
Example of Outgassing Acids in Tape Products Tape Sample B Acetic acid detected in outgas after 2 minutes. Acetic Acid Standard Fully outgassed at 740 ng/cm 2 or 33 ppm w after 14 hours. FTIR outgassing spectra of a tape sample and standard at 85 o C Cummulative Outgassing Concentration (ng/cm2) 800 700 600 500 400 300 200 100 0 0:00 2:24 4:48 7:12 9:36 12:00 14:24 16:48 Time (hr:min)
FTIR Detection of Bases Collection Time < 2 minutes ammonia 8.5 ppm v Absorbance diethyl amine 25 ppm v methyl amine 40 ppm v Energy (wavenumbers cm -1 )
Example of Outgassing Bases in Tape Products Tape Sample C Ammonia Standard Ammonia detected in outgas after 2 minutes. Fully outgassed at 245 ng/cm 2 or 32 ppm w after 30 minutes. FTIR outgassing spectra of a tape sample and standard at 85 o C Cummulative Outgassing Concentration (ng/cm2) 350 300 250 200 150 100 50 0 0:00 0:14 0:28 0:43 0:57 1:12 Time (hr:min)
FTIR Detection of Semi-Volatiles Collection Time < 2 minutes Octamethylcyclotetrasiloxane 10 ppm v Absorbance ethylhexyl acrylate 21 ppm v phenol 10 ppm v Energy (wavenumbers cm -1 )
Example of Outgassing Semi- Volatiles in Tape Products Tape Sample D Siloxane (OMCTS) Standard Siloxanes detected in outgas after 2 minutes. Fully outgassed at 20 ng/cm 2 or 2 ppm w after 30 minutes. 25 FTIR outgassing spectra of a tape sample and standard at 85 o C Note: OMCTS is a surrogate standard for all siloxanes through the 800 cm -1 band. Cummulative Outgassing Concentration (ng/cm2) 20 15 10 5 0 0:00 0:07 0:14 0:21 0:28 0:36 0:43 0:50 0:57 1:04 Time (hr:min)
Simultaneous Detection of Multiple Compounds in Tape Samples 3 Cummulative Outgas Concentration (ppmv) 2.5 2 1.5 1 0.5 acetic acid (MA) ammonia (MB) methacrylic acid (MA) siloxanes (MC) 0 0:00 0:07 0:14 0:21 0:28 0:36 0:43 0:50 0:57 1:04 Time (hr:min)
FTIR Static Headspace Can quantitate and speciate, in a timely manner, molecular compounds that are outgassed from materials destined for the hard disk drive. Useful on manufacturing floor for routine evaluation of semi-finished or finished goods for unwanted contaminants and control charting. Useful in product development and product certification activities.