Activated He:H₂ Strip of Photoresist over Porous Low-k Materials

Abstract:

• Periodical: Solid State Phenomena (Volumes 103-104)
• Pages: 341-344
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.103-104.341
• Online since: April 2005
• Authors: Qing Yuan Han, Brian White, Ivan L. Berry, Carlo Waldfried, O. Escorcia
• Keywords: He:H₂, Low Damage, Low-k Materials, Resist Strip

References

[1] US Patent # 6,630,406, Granted October 7, 2003.

[2] C. Waldfried, et al., Electrochemical and Solid State Letters, volume 6, issue 12, pp. G137 - 139, 2003.

[3] Q. Han et al, Proceedings of the SEMICON China 2005 Technical Symposium, Shanghai, China, 2005.

[4] E. Sparks et al, Proceedings of the Sematech Wafer Clean & Surface Prep Conference 2004, Austin, TX. Table I. Electrical Testing Results 0.175/0.225 Features Split # of Wafers RSERPYA 6 (kOhm) CAP__YJ D (pF) IBRIGYJ1 (log Amps) RC (pF-kOhm) Estimated k-value ISMT N2H2 POR 5 36.0 10.2 -12.2 367.1 2.7 ISMT N2H2 CVD 4 30.9 10.6 -12.4 327.2 2.3 HeH2 CVD No Clean 4 28.3 11.8 -12.5 334.7 2.4 HeH2 CVD dHF Clean 4 28.6 11.7 -12.4 332.7 2.4 HeH2 CVD ddHF Clean 4 28.2 11.7 -12.5 329.2 2.3 HeH2 CVD DearClean 4 27.9 11.6 -12.6 326.0 2.3 Figure 1. TDS data indicate that the moisture uptake for the He:H2 treated films is very small. Figure 2: Dielectric constant (k-value) changes of JSR5109 film after exposed to the He:H2 strip conditions for 60 seconds, measured at room temperature and at 200ºC. Figure 3. FTIR spectra shows that the He:H2 strip preserves the chemical properties of the p-MSQ low-k film. Moisture Uptake from TDS measurement 0 2 4 6 8 10 12 14 16 210 240 270 300 330 360 390 420 Temperature [C] Moisture Uptake [%] He/H2 Ash N2/H2 Ash Control 0.175/0.225µm 0.25/0.30µm 0.175/0.225µm 0.25/0.30µm Figure 4. Cross-section SEM inspection shows good CD retention, no cap rounding, and no further etch stop loss on p-MSQ trench structures after resist removal using the HeH2 strip. 1112626 RC Product (.175/.225) 0 10 20 30 40 50 60 70 80 90 100 300 320 340 360 380 400 420 RC Product (pF-kOhm) % Distribution N2H2 POR N2H2 CVD HeH2 CVD nocln HeH2 CVD dHF HeH2 CVD ddHF HeH2 CVD deer 2.00 2.10 2.20 2.30 2.40 2.50 123456789 slot# k k@RT k@200C 210 240 270 300 330 360 390 420 control Temp. [C]2.00 2.10 2.20 2.30 2.40 2.50 123456789 slot# k k@RT k@200C 210 240 270 300 330 360 390 420 control Temp. [C] Figure 5. Electrical testing results - RC product for 0.175/0.225 test structure. All 4 splits with He:H2 dry strip yielded good results. 1112626 BTS 40V, 250C 1% 10% 20% 30% 40% 50% 60% 70% 80% 90% 99% 1 10 100 1000 Package lifetime (hour) Cumulative Probability N2H2 + CV D HeH2 + CV D+ddHF N2H2 POR He/H2+CVD+deer 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 400 900 1400 1900 2400 2900 3400 3900 Wavenumber (cm-1) Figure 6. Reliability data show that the He:H2 strip + CVD barrier + Deerclean wet clean split had no failures after 500 hours of bias-temperature stressing. Absorbance Pre 15_post He/H2 (60") 16_post N2/H2 (60") C-H Si-CH3 Si-O Si-H Si-OH