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Trial Number 5

Client Number 107

Project Number 1

Trial Purpose:

To determine if previous tested cleaners could work at lower dilutions using immersion or ultrasonic cleaning.

Date Run:

07/29/1999

Experiment Procedure:

Two aqueous cleaners previously tested were made into 10% solutions using DI water in a 600 ml Pyrex beakers. The semi-aqueous cleaner was made into 10, 20 and 50% solutions also in beakers using DI water. Preweighed coupons were coated with the negative photoresist and weighed again. Three coupons were placed into the 20 and 50% solutions and cleaned using stir-bar-agitation. Observations were made at 10 and 30 minutes. At the end of the 30 minutes, the coupons were rinsed with a tap water bath at 120 F for one minute and air dried for two hours. The coupons were weighed again and the efficiencies calculated.

All cleaning solutions and dilutions were used to clean coupons using a Crest 40 kHz ultrasonic tank model 4Ht 1014-6. Observations were made at 5, 10, 15 and 20 minutes. At the end of the 20 minutes, coupons were rinsed in a tap water spray for one minute at 120 oF. Coupons were dried at room temperature for two hours. After drying coupons were weighed and efficiencies were calculated. In addition to the ultrasonic cleaning, one coupon was immersed in each solution and allowed to soak overnight at room temperature with no agitation. Coupons were rinsed in tap water spray for one minute at 120 F and dried at room temperature. Gravimetric analysis was performed to determine the effectiveness of the cleaning.

SUBSTRATE MATERIAL: Aluminum coupons (1100-H14)
CONTAMINANTS: Olin HNR 120 Negative Photoresist (CAS#s: 1330-20-7 [65-70%]; 100-41-4 [15-18%]; 68441-13-4 [9-15%]; 5284-79-7 [0.1-0.6%])

Trial Results:

The immersion cleaning using the two concentrations of Bio-T Max proved unsuccessful after 30 minutes. Table 2 lists the efficiencies and the observations made at ten and 30 minutes.

Table 2. Immersion Cleaning 30 Min

Cleaner Bio-T Bio-T
Conc Used 20% 50%
Coupon 1 5.08 5.87
Coupon 2 5.36 9.03
Coupon 3 4.66 9.28
Average 5.03 8.06
Obs @ 10 min some dissolving good dissolving
Obs @ 30 min could wipe off could wipe off

The use of the ultrasonic energy did increase the effectiveness of the cleaning solutions. The 50% solution of Bio-T Max was mostly clean after 20 minutes. Table 3 lists the results of the gravimetric analysis and lists the observations after each five minute interval.

Table 3. Ultrasonic Cleaning 20 Min

Cleaner Bio-T Bio-T Bio-T FO GT
Conc 10% 20% 50% 10% 10%
Coupon 1 28.83 29.67 78.85 7.89 12.01
Coupon 2 25.28 29.75 96.75 8.04 16.63
Coupon 3 32.37 23.04 69.78 9.99 11.1
Average 28.83 27.48 81.79 8.64 13.24
Obs @ 5 not good could peel off could wipe off No cleaning No cleaning
Obs @ 10 spotty removal spotty removal became mushy Little cleaning Some dissolving
Obs @ 15 more spot removal more spot removal easily removed could peel off More dissolving
Obs @ 20 could peel off more spot removal almost clean no dissolving could peel off

The fourth table lists the calculated efficiencies after the coupons soaked overnight at room temperature
with no agitation. Both the Bio-T Max 20 and 50% solutions were very effective in removing the contaminant
from the coupons.

Table 4. Overnight Soak Results

GT FO BT-10% BT-20% BT-50%
10.7 5.36 38.64 87.57 98.02

Success Rating:

A follow up test, usually based on company input.

Conclusion:

The removal of the negative photoresist was effectively removed by diluted solutions of Bio-T Max.  Using Bio-T Max at 50% dilution and ultrasonic energy resulted in ~80% removal after 20 minutes.  The same dilution was ~98% effective after soaking for 24 hours.  A 20% dilution of Bio-T Max removed ~88% of the contaminant also after soaking for one day.

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