ELIMINATION OF IN-PROCESS MULTILEVEL INTERCONNECT STRESS VOIDS THROUGH OPTIMIZATION OF PLASMA ENHANCED CHEMICAL VAPOR OXIDE DEPOSITION PARAMETERS

Glass dielectric films produced by plasma enhanced chemical vapor deposition (PECVD) have been demonstrated, depending on the deposition conditions, to absorb varying amounts of moisture over time with a commensurate increase in compressive stress level. When these films were used as interlayer dielectrics in a multilevel Al-1.5%Cu metal system, a strong correlation between the dielectric moisture absorption/desorption, stress drift, and metal stress void formation was observed. A statistical optimization of a PECVD deposition process is presented which eliminated in-process metal line voiding.