Patent ID: 6959586

Claim:
A method for evaluating a multiplicity of data handling devices each having a sealed chamber with several interior surfaces, the method comprising steps of: (a) selecting at least one of the multiplicity of data handling devices, the selected device(s) having a cavity and a sealed housing portion adjacent thereto by steps comprising: leak-testing at least some of the multiplicity of data handling devices; and finalizing the selection step by selecting the at least one device based on an outcome of the leak-testing step, the finalizing step comprising: identifying a range of marginal leak rates broadly enough so as to include at least one leak rate corresponding to one of the multiplicity of data handling devices; and identifying a subset of the data handling devices such that each identified device has a leak rate within the identified range, the identified device(s) being the selected device(s); and (b) providing an impurity chamber at a first pressure and containing thousands of dispersed gas-borne particles that each contain a marker impurity that is substantially absent from all of the interior surfaces of the selected device(s); (c) exposing the sealed portion of the selected data handling device(s) to the impurity chamber while maintaining a pressure of the cavity at a second pressure lower than the first pressure; and (d) evaluating the multiplicity of data handling devices based on an indication of whether the marker impurity was present in the selected device(s) in an amount exceeding a predetermined threshold.