To measure the depth of the through silicon vias on 300 mm silicon wafers, a measuring machine was developed. Based on the preceding research in a laboratory environment, the machine was designed and built by modifying the optical probe for reducing the mass, combining a visible optical microscope to monitor the location of the measuring points, and constructing the metrology frame for large silicon wafers. The depths of the three different-sized through silicon vias were measured repeatedly to estimate the repeatability. Moreover, comparative measurement was carried out to verify the measured depth values. The total measurement time was also estimated by measuring 110 through silicon vias at different locations. According to the measurement results, the measurement performance satisfied the technical requirements of the industry in terms of repeatability, accuracy, and measurement time.

In this investigation, we describe a metrological technique for surface and thickness profiles of a silicon (Si) wafer by using a 6 degree of freedom (DOF) stitching method. Low coherence scanning interferometry employing near infrared light, partially transparent to a Si wafer, is adopted to simultaneously measure the surface and thickness profiles of the wafer. For the large field of view, a stitching method of the sub-aperture measurement is added to the measurement system; also, 6 DOF parameters, including the lateral positioning errors and the rotational error, are considered. In the experiment, surface profiles of a double-sided polished wafer with a 100 mm diameter were measured with the sub-aperture of an 18 mm diameter at 10x10 locations and the surface profiles of both sides were stitched with the sub-aperture maps. As a result, the nominal thickness of the wafer was 483.2 μm and the calculated PV values of both surfaces were 16.57 μm and 17.12μm, respectively.