Examples of Defect Adders Within the Oxide-Masked Al Etching Process Sequence

Examples of Defect Adders Within the Oxide-Masked Al Etching Process Sequence

Material Name: Aluminium
Record No.: 41
Primary Chemical Element in Material: Al
Sample Type: Layer
Uses: Etching
Etchant Name: None
Etching Method: Dry etching
Etchant (Electrolyte) Composition: No data
Procedure (Condition): No data
Note: As illustrated in Figure 1, the defect types, referred to as “post hard-mask etch residue,” “post metal etch residue,” “blocked etch metal island,” “particle,” “bridging,” “particulate bridging,” and “corrosion,” were found at the early stage of development. Interestingly, the major adders of post hard-mask etch residue, post metal etch residue, and blocked etchmetal island were particularly high in the oxidemasked Al patterning but few in the conventional resistmasked Al patterning. From the observations of scanning electron micrographs as shown in Figure 1, these three defect types pose a tangible and substantial yield risk due to their subtle physical characteristics and high density on wafer. Hence, it is important to understand the behavior of these defect adders within the Al etching process sequence.
Reference: Hong-Ji Lee, Che-Lun Hung, Chia-Hao Leng, Nan-Tzu Lian, Ling-Wu Young, Tahone Yang, Kuang-Chao Chen, and Chih-Yuan Lu, Etch Defect Characterization and Reduction in Hard-Mask-Based Al Interconnect Etching, International Journal of Plasma Science and Engineering, Volume 2008, Article ID 154035, pp. 1-5.

Figure 1: Examples of defect adders within the oxide-masked Al etching process sequence.