Optical coating uniformity of 200 mm (8') diameter precut wafers

摘要

Automated spectroscopic profiling (mapping) of a 200 mm diameter near infrared high reflector (centered at 1064 nm) are presented. Spatial resolution at 5 mm or less was achieved using a 5 mm x 1.5 mm monochromatic beam. Reflection changes of 1.0% across the wafer diameter were observed under s-polarized and p- polarized conditions. Redundancy was established for each chord by re-measuring the center of the wafer and reproducibility of approximately <0.1% was demonstrated by duplicate measurements. These measurements demonstrate informative spatial spectroscopic information can be obtained on large diameter samples. Multi-angle Photometric Spectroscopy (MPS) was used to measure the reflectance and transmittance of a sample across a range of angles (θ_1) at near normal angles of incidence (AOI). A recent development by Agilent Technologies, the Cary 7000 Universal Measurement Spectrophotometer (UMS) combines both reflection and transmission measurements from the same patch of a sample's surface in a single automated platform for angles of incidence in the range 5°<|0j|<85° (i.e. angles on either side of beam normal noted as +/-). We describe the use of MPS on the Cary 7000 UMS with rotational () and vertical (z) sample positioning control. MPS(0i,<|>,z) provides for automated unattended multi-angle R/T analysis of at 200 mm diameter samples with the goal to provide better spectroscopic measurement feedback into large wafer manufacturing to ensure yields are maximized, product quality is better controlled and waste is reduced before further down-stream processing.