Japan Analylical Industry Co., Ltd.
Naoki Oguri Ph. D.
Outgas Analysis for Wafer Industries
Investigation of Origin Compound Analysis in the Outgas Exhausted from the Carrier Box Material

The wafer was packed into the carrier box by the wafer manufacturing company, it was then shipped to thesemiconductor company.
It well-known that the wafer was contaminated by outgas from the polymer materiais which are composed thebox during the transporting.
At the first, total outgas from a carrier box was analyzed by illustrated system in Fig. 12.

Fig. 12 Schcmatic diagram ol the outgas analyzer system

Carrier box : 25 ea of 8" wafers are can be entered in the box.
The materials of the box: Outside box and carrier : Polypropylene; Cover : Polycarbonate; Wafer rib :Polybutylene terephthalate; Seal : EPDM
Sellling inlet and outlet line for the box: Two connectors for inlet and outlet to be connected purge gas inlet
and PAR are made by using oil free drill and M6 p=1 taps on the cover of the box.
Sampling : Purged by He 300 ml/min for 60 min at room temperature after pre-purging 20 min in order to rejectoriginal organic substances in the box.

Obtained VOC chromatogram from the carrier box by mentioned the above method is showed in the top of Fig.
13. Before 5 min of RT compounds are detected as environmental compounds in measured laboratory, because
the prepurging 20 min was not enough time. After 5 min of RT, a lot of paraffin and olefin peak are observed.
Especially, ethylbenzaldehyde (8),BHT decomposed compound (10), BHT (11 ) and DOP (12) are observed aspolymer additives. (Total outgas amount on chromatogram for after RT 5 min of the carrier box was 240 ng.)
In order to investigate the origin of those polymer additives, 3 g of the cut seal was set into the sample tube ofJHS-100A, it was then analyzed by P&T-GC/MS after heating the sample 80℃ for 30 min purging, thechromatogram is shown in the middle of Fig. 13. Peak No. 6, 7, 9 and 11 are quite same for the both
chromatogram the top and the middle.
Also, 100 mg of cut carrier (inside carrier) was anaiyzed by the same method as the seal. Chromatogram of theoutgas from the carrier is shown in the bottom of Fig. 13. The peak No. 8 and 11 are observed on the both
chromatogram the top and the bottom.

1 : Acetonitrile ; 2 : Chloroform : 3 : Heptane ; 4 : Toluene ; 5 : Xylcne ; 6 : Paraffin and olefin ; 7 : n-C12 ;8 : Ethylbenzaldehyde ; 9 : n-C15 ; 10 : 2,6-di-t-butyl-4-methyl-ene-2,5-cyclohexadiene-1-one (decomposedcompounds from BHT) ; 11 : BHT ; 12 : DOP ; 13 : n-C13 ; 14 : Dimethylsilicone (n=6) ; 15 : n-C16 ;16 : Butyl hexanoate ; 17 : Silicone compounds ; 18 : Butyl lauratebottom of Fig.13. The peak NO.8 and 11 are observed on the both chromatogram the top and bottom.

Results
Origin of peak No. 1 and 2 : from circumstances in the laboratory
Origin of peak No. 4 and 5 : from VOC in normal air
Origin of peak No. 6, 7, 9 and 1 1 : from the seal
Origin of Peak No. 8, 10 and 1 2 : from carrier

Analyticail Condilion :Instrument : GC/MS : HP5973, EI, 70 eV; Outgas collector : hand made; P&T : JHS-100A
Purging : The carrier box=300ml/min for 60 min, The polymer=each 3g 30ml/min for 30min at 80℃, He ; Thermal
extraction :235℃ for 20 min ; PAT : Tenax GR;
Oven temp. of JHS-100A : 200℃;

Secondary adsorption tube : Quartz wool;

Column : DB-2, 0.25 ƒÊ, i.d.0.25 x 30 m, 40℃ (hold 3 min)-280℃, 10℃/min