Investigation into environmentally friendly alternative cleaning processes for hybrid microcircuits to replace vapor degreasing with 1,1,1-trichloroethane. Final report

Technical Report · Sat Feb 01 04:00:00 EST 1997

DOI:https://doi.org/10.2172/481597· OSTI ID:481597

Adams, B E

Two cleaning processes, one aqueous and one nonaqueous, were investigated as potential replacements for the vapor degreasing process using 1,1,1 trichloroethane (TCA) for hybrid microcircuit assemblies. The aqueous process was based upon saponification chemistry. A 10% solution of either Kester 5768 or Armakleen 2001, heated to 140 F, was sprayed on the hybrid at 450 psig and a flow rate of 5 gpm through a specially designed nozzle which created microdroplets. The nonaqueous process was based upon dissolution chemistry and used d-limonene as the solvent in an immersion and spray process. The d-limonene solvent was followed by an isopropyl alcohol spray rinse to remove the excess d-limonene. The aqueous microdroplet process was found to be successful only for solder reflow profiles that did not exceed 210 C. Furthermore, removal of component marking was a problem and the spray pressure had to be reduced to 130 psig to eliminate damage to capacitor end caps. The d-limonene cleaning was found to be successful for solder reflow temperature up to 250 C when using a four-step cleaning process. The four steps included refluxing the hybrid at 80 C, followed by soaking the hybrid in d-limonene which is heated to 80 C, followed by spray cleaning at 80 psig with room temperature d-limonene, followed by spray cleaning at 80 psig with room temperature IPA was developed to remove residual flux from the hybrid microcircuits. This process was the most robust and most closely matched the cleaning ability of TCA.

• Research Organization: Allied-Signal Aerospace Co., Kansas City, MO (United States). Kansas City Div.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00613
• OSTI ID: 481597
• Report Number(s): KCP--613-5850; ON: DE97052911
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
42 ENGINEERING
54 ENVIRONMENTAL SCIENCES
CLEANING
MATERIAL SUBSTITUTION
MICROELECTRONIC CIRCUITS
OZONE LAYER
PERFORMANCE
PROGRESS REPORT
SOLVENTS