Application of micro-Raman and photoluminescence spectroscopy to defect and thin film characterization

Applications of micro-Raman and micro-Photoluminescence spectroscopy to defect and thin film characterization in semiconductor processing and equipment development are presented. The Raman spectrometer is coupled to a confocal laser Defect Review Tool (DRT). This system locates particles as small as 0.2 mum, both on 200 mm and 300 mm wafers. Raman spectroscopy is fast, non-destructive; can be performed in ambient, and is capable of providing chemical state and structural (phases, stress) information down to sub-micron dimension. Its application is material specific, however, since some materials do not have Raman-active vibrations or sufficient cross-section, or have a probing depth too long (optically transparent) to be useful. In general, chemical state information is obtainable from vibrational fingerprints of covalently bonded compounds (organic, SCH, Si-Si, etc.), some ceramics (e.g. Zr-O, Al-O etc.), and ionic species (e.g. ammonium salts). Structural information, such as residual stress (e.g. poly-Si) and phase distinction (e.g. amorphous/diamond carbon; high/low residual phases of silicide) can sometimes also be obtained. Specific examples from Applied Materials development programs are presented. These include identification and distinction of carbon particles from different hardware sources generated by NF3 clean; organic defects on Cu after CMP; identification of the compound causing Br based particles after poly-gate etch; and distinction between ceramic based aluminum particles and anodized based aluminum particles. In the area of thin film characterization we have used micro-Raman to characterize residual build-up on hardware (e.g. residue from showerhead used in the W- CVD process chamber), and the process development of coatings and film products (e.g. diamond, poly-Si).