IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Manufacturing Science and Technology Tuesday Sessions
       Session MS-TuM

Paper MS-TuM2
Cleaning Procedures in Wafer Processing: Analytical Challenges for Root Cause Determination of Particle Problems

Tuesday, October 30, 2001, 8:40 am, Room 131

Session: Process Integration and Factory Productivity
Presenter: C.C. Wang, Applied Materials, Inc.
Authors: C.C. Wang, Applied Materials, Inc.
Y.S. Uritsky, Applied Materials, Inc.
C.R. Brundle, Applied Materials, Inc.
Correspondent: Click to Email
Common dry clean procedures used in the wafer processing industry are: substrate pre-clean of individual wafer prior to deposition (gentle Ar@super +@ sputter), and hardware clean after many processed wafers to remove the sputtered material build-up (harsh NF@sub 3@ usually). Particle failures can result from both procedures, however, and are a severe industry problem. In the Ar@super +@ pre-clean a gradual build-up of by-products of cleaning occurs on chamber surfaces. These can chemically react with the hardware material, releasing composite particles through stress (proven by detailed particle morphology observation). In the NF@sub 3@ case, the fluorine radicals, intended for removing deposits by forming volatile products, often attack hardware itself producing particles. In both cases particle analysis is critically needed to determine exactly what piece of hardware is being attacked and by what mechanism for the purpose of hardware and process improvements. The sophistication of the analytical work required for finding root cause is high. In this paper we describe how careful SEM/EDX work, supported by FIB and Raman/Photoluminescence, identified root cause in both NF@sub 3@ and Ar@super +@ clean particle failures. In the NF@sub 3@ case the critical issue was to establish, without any doubt, that generated particles scavenged by an oxide monitor wafer, contained no oxygen and only Al and F. In the Ar@super +@ pre-clean case it was demonstrated that particles consisted of thin, plate-like bi-layers of sputtered substrate material (SiON in this case) and amorphous Al@sub 2@O@sub 3@ from the surface of the plasma degraded ceramic dome. In both cases modeling the EDX spectra using STRATAGEM@footnote 1@ software for multi-layer thin film structures (and here applied to particles) was important in reaching definitive conclusions, which were then used in the successful defect reduction actions. @FootnoteText@ @footnote 1@ STRATAGEM is a registered trademark of SAMx.