The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1977
Filed:
Jun. 07, 1976
Willis Ray Goodner, Chandler, AZ (US);
James Nelson Smith, Tempe, AZ (US);
John Horvath, Chandler, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Improved stabilization of 1,1,1-trichloroethane is obtained by employing a free radical scavenger as a stabilizer which will trap trichloromethyl radicals, making them unavailable for formation of acidic species in the trichloroethane. Examples of such free radical scavengers include trichloroethylene, tetrachloroethylene, or fluorene. Compositions in accordance with the invention consist essentially of the 1,1,1-trichloroethane and from about 0.1 volume percent to about 5 volume percent of the free radical scavenger. In the fabrication of semiconductor devices in which the so stabilized trichloroethane is employed as a degreasing solvent, the acidity of the trichloroethane composition may be monitored, and additional free radical scavenger added to the solution to maintain the acidity within acceptable limits, thus allowing the trichloroethane to be used indefinitely.