The purpose of this part of IEC 60749 is to test and verify that the markings on semiconductor devices will not become illegible when subject to solvents or cleaning solutions commonly used during the removal of solder flux residue from the printed circuit board assembly process.This test is applicable for all package types. It is suitable for use in qualification and/or process monitor testing. The test should be considered non-destructive. Electrical or mechanical rejects may be used for the purpose of this test.In general, this test of permanence of marking is in conformity with IEC 60068-2-45 but, due to specific requirements of semiconductors, the clauses of this standard apply.NOTE 1 This procedure does not apply to laser branded packages.Many available solvents that could be used are either not sufficiently active, too stringent, or even dangerous to humans when in direct contact or when fumes are inhaled.NOTE 2 The composition of solvents used in this standard, is considered typical and representative of the desired stringency as far as the usual coatings and markings are concerned.