300-mm Production-Worthy Magnetically Enhanced Non-Bosch Through-Si-Via Etch for 3-D Logic Integration

• Published in: IEEE transactions on semiconductor manufacturing Vol. 23; no. 2; pp. 293 - 302
• Main Authors: Teh, W H, Caramto, R, Chidambaram, Thenappan, Wei Wang, Arkalgud, Sitaram R, Saito, T, Maruyama, K, Maekawa, Kaoru
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Anisotropy; Applied sciences; Couplings; Design. Technologies. Operation analysis. Testing; Electronics; Etch; Etching; Exact sciences and technology; Integrated circuits; Logic; Magnetic anisotropy; Magnetic semiconductors; Masks; non-Bosch; Perpendicular magnetic anisotropy; Plasma applications; Plasma materials processing; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Three dimensional; three-dimensional integration; Through-silicon vias; through-silicon-via (TSV); Undercuts; Variability; Critical size; Roughness; Aspect ratio; Three dimensional structure; Etch; Depth profile; three-dimensional integration; Integrated circuit; Dipole; Capacitive coupling; Void; non-Bosch; Wafer; Via hole; through-silicon-via (TSV)
• ISSN: 0894-6507; 1558-2345
• DOI: 10.1109/TSM.2010.2046083

We report a process development route toward 300-mm production-worthy non-Bosch through-silicon-via (TSV) etch with critical dimensions between 1-5 ¿m and aspect ratios up to 20:1 for 3-D logic applications. The etch development was performed on an experimental alpha-tool: a magnetically enhanced capacitively coupled plasma etcher with a dipole ring magnet that aims to capture the strengths (anisotropicity, profile uniformity) while eliminating the weaknesses (scalloping, undercut, residues) of a nominal Bosch process. Key factors contributing to the control of sidewall taper and roughness, etched TSV volume and depth, mask undercut, local bowing effects, and within wafer (WIW) center-to-edge depth and profile uniformity were evaluated. TSVs with nominal sizes of 5 × 25 ¿m, 5 × 40 ¿m and 1 × 20 ¿m with less than 1% WIW nonuniformity, negligible silicon scalloping/mask undercut, and good profile anisotropicity were developed. Up to 3 × 20 ¿m and 5 × 25 ¿m void-free Cu-filled TSVs were demonstrated with both vertical TSVs and tapered TSVs.