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Examination of Discolored DI Water Tube Pardeep Sharma, and Terry KungRQC-A, NXP, Kaohsiung, Taiwan

05, 09, 2014COMPANY CONFIDENTIALSeptember 5, 2014Subject / Department / Author - 2Summary (Findings) 1. DI water tube of chemical room shows discoloration. Lower side of tube looks brown- black, but, upper side has blue-green deposits. Besides, algae-diatoms are present in brown-black and blue-green colour parts of tube. Blue-green coloured part have many micro particles rich in Fe, S, Na, Al.

2. EDX of new DI water tube shows C, O, Si. Surface of new tube is clean. No algae like features.

3. EDX of discoloured DI water tube shows following: Black-brown area: C, O, Si, Fe; Blue-green area: C, O, Si, Fe, Na, S, Al,

4. Blue-green colour of discoloured DI water tube resembles with FeSO4.7H2O, which is very common Fe mineral.

5. Bacillariophyta/ Algae/ Diatom were found everywhere on discoloured DI water tube.

COMPANY CONFIDENTIALDiscussion and SuggestionsPresence of trace metal (ppm) contamination in DI water need to be verified. Or data from last several months can be used to access the situation.

If for given volume (example 1 L, or 10 L) of DI water, that is used at a time, the metal contamination is found to be within technical spec of DI water, then no action is needed.

If metal contamination in DI water is within spec, then that discoloration can be attributed to following: (1) trace metal contamination from fumes of HNO3 or H2SO4 or other chemicals. Or (2) over a long period of time, the accumulation of metal impurities by algae like structure formed onto inner surface of DI water tube

If metal contamination is beyond spec of pure DI water, then corrective action is needed. September 5, 2014Subject / Department / Author - 3COMPANY CONFIDENTIALOptical Microscope Image of Discolored Tube

September 5, 2014Subject / Department / Author - 4Black-brown discolorationBlue-green discolorationBoth (black-brown, & blue-green) type of discolored areas show presence of algae and diatoms, and brown colored micro-particles (shown above).

COMPANY CONFIDENTIALSEM Image of Inner Surface of DI Water Tube

September 5, 2014Subject / Department / Author - 5New TubeDiscolored Tube with AlgaeBlue-Green area has lotsof such micro-particles.No algae type structure in new tubeCOMPANY CONFIDENTIALBacillariophyta/ Algae/ Diatom on Discolored DI Water Tube

September 5, 2014Subject / Department / Author - 6

Diatom/ BacillariophytaAlgaeDiatoms as shown above are known to found in fresh water with high mineral concentration. COMPANY CONFIDENTIALEDX of new DI Water Tube

September 5, 2014Subject / Department / Author - 7Pt is from sputter coating on sample.COMPANY CONFIDENTIALEDX of Discolored DI Water TubeSeptember 5, 2014Subject / Department / Author - 8

Pt is from sputter coating on sample.COMPANY CONFIDENTIALEDX Micro-Particle of Discolored DI Water TubeSeptember 5, 2014Subject / Department / Author - 9Pt is from sputter coating on sample.

COMPANY CONFIDENTIAL