摘要 |
An interferometric method for profiling the topography of a sample surface comprises: (i) a first interferometric profiling step at a first magnification M1 to produce a map comprising pixels with planar (X,Y)-coordinates corresponding to the area of the sample surface, (ii) identifying pixel(s) which meet or exceed a Cut-Off Threshold, and meet or exceed a parameter NNAP; (iii) identifying pixel(s) for which no z-coordinate has been recorded; (iv) generating a Low Magnification Frame File (LMFF) which comprises the (X,Y) coordinates of the pixels derived from steps (ii) and (iii); (v) a second interferometric profiling step at a second magnification M2, wherein M2>M1, wherein only selected regions of the sample surface are analysed, said selected regions comprising the features associated with the (X,Y)-coordinates of the pixels in the Low Magnification Frame File; and further comprising a step selected from: (vi) analysing the output of the second interferometric profiling step to differentiate between an intrinsic defect and an extrinsic defect; (vii) assessing whether said sample surface meets one or more quality control standard(s) and/or one or more target property or properties; and (viii) assessing whether said sample surface is suitable as a surface for subsequent coating. |