Title :
Impact of interface preparation on defect generation during wafer bonding
Author :
Baumgart, H. ; Pinker, R.D. ; Steigmeier, E.F. ; Auderset, H. ; de Kock, A.J.R.
Author_Institution :
Philips Lab., Briarcliff Manor, NY, USA
Abstract :
Large interfacial voids in bonding and etch-back silicon-on-insulator (BESOI) are discussed. After wafer contacting, the presence of several large interfacial voids is observed. High-resolution X-ray topographs confirm either foreign particles or epitaxial spikes in the center region of voids as the reason for nonbonding. The voids at the bonding interface contain trapped air pockets, which are under pressure. In general, as a result the entire area covered by the voids is lost to the SOI film due to cracking and delamination during the etch-back procedure. In order to investigate the lattice damage distribution and the strain related to it, elastic light scattering experiments were performed. The findings of local networks of elastic distortion are an indication of insufficient wafer flatness and surface finish. BESOI wafers were examined again after they had been subjected to the 30-min high-temperature polymerization bonding step at 1050°C. The areas of the voids that had been free of extended defects following the wafer contracting step then exhibited a dense network of misfit dislocations. During thermal annealing at 1050°C the stresses at the perimeter of the voids and at the site of particulate contamination increased to the point where they exceeded the critical resolved shear stress of silicon and dislocations were nucleated
Keywords :
X-ray diffraction examination of materials; annealing; delamination; dislocation nucleation; elemental semiconductors; fracture; interface structure; light scattering; semiconductor-insulator boundaries; silicon; voids (solid); 1050 C; BESOI wafers; Si; X-ray topographs; bonding and etch-back SOI; cracking; critical resolved shear stress; defect generation; delamination; dense network; dislocation nucleation; elastic distortion; elastic light scattering; elemental semiconductors; epitaxial spikes; foreign particles; high-temperature polymerization bonding; interface preparation; large interfacial voids; lattice damage distribution; local networks; misfit dislocations; site of particulate contamination; thermal annealing; trapped air pockets; wafer bonding; Capacitive sensors; Delamination; Etching; Lattices; Light scattering; Silicon on insulator technology; Surface cracks; Surface finishing; Thermal stresses; Wafer bonding;
Conference_Titel :
SOS/SOI Technology Conference, 1989., 1989 IEEE
Conference_Location :
Stateline, NV
DOI :
10.1109/SOI.1989.69783