Plasma etch control by HERCULES Plasma etch control
Plasma etch control by HERCULES Plasma etch control by means of physical plasma parameter measurement with HERCULES A. Steinbach F. Bell D. Knobloch Sematech AEC/APC Symposium X S. Wurm Ch. Koelbl D. Köhler -1 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Contents - Introduction - Motivation - Plasma monitoring tool HERCULES - Al etch on LAM TCP 9600 SE - Contact etch on Applied Materials Centura Mx. P+ - Summary Sematech AEC/APC Symposium X -2 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Our way of plasma processing today – an effective way ? Process parameters power pressure B field gas flow. . . „Black Box“ called plasma processing Process results etch rate uniformity selectivity particles. . . . - Experience and statistical methods in process development - “Process Monitoring” and Tool control by test wafers Sematech AEC/APC Symposium X -3 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Measuring Techniques for real time Plasma Monitoring rf probe rf voltage rf current power Process parameters external power pressure B field gas flow body temp. Ion flux probe j+ (wall) Process parameter rf voltage (wafer) rf current bias voltage effective power Chamber parameters surface temp. polymer e. g. gas ad / desorption depending on ion current We begin to measure ! Plasma excitation Power balance and potential distribution electron collision rate, electron energy distribution electron density plasma potential bulk power Hercules ion density ion temperature neutral densities neutral temp. excitations Wafer Surface ion energy ion current radiation neutral flows (radicals) surface temp. layer thickness OES k*i( ) Process Results external measured etch rate uniformity selectivity particles Interferometry Reflectence spectroscopy layer thickness ne, e, PBulk Sematech AEC/APC Symposium X Species in the volume -4 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Basic HERCULES Model High Frequency Electron Resonance Current Low Pressure Spectroscopy Sematech AEC/APC Symposium X -5 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Principle and experimental setup Algorithm - Passive electrical method, no influence on the plasma - Integral measurement Sematech AEC/APC Symposium X -7 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES SEERS provides reciprocally averaged parameters Self Excited Electron Resonance Spectroscopy Sematech AEC/APC Symposium X -8 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES TCP: Al etch - trend analysis main etch - Cl 2 - MFC failure Sematech AEC/APC Symposium X - Cleans - 10 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES TCP: Al etch in Cl 2 - first wafer effect First wafer effect in main etch Sematech AEC/APC Symposium X - 12 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES TCP: Al etch - with / without barrier (Ti. N, Ti) Ti layer detected Sematech AEC/APC Symposium X - 13 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch: Plasma parameters dependíng on process parameters Change of process chemistry strong nonlinear correlation Sematech AEC/APC Symposium X - 16 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - Etch rate BPSG (blanket) depending on plasma parameters Obvious correlations between etch rate and electron collision rate electron density bulk power Sematech AEC/APC Symposium X - 17 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - Contact angle depending on plasma parameters Change of process chemistry no obvious correlation between electron density and contact angle Sematech AEC/APC Symposium X - 18 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: Chamber monitoring of contact etch processes on product wafers Process mix in Applied Materials Centura Mx. P+ chamber: Oxide and Nitride etch with CF 4 / CHF 3 / Ar / O 2 chemistry Process 1 Process 2 Process 3 Descum Step 1 Step 2 --BPSG --- N 2 / O 2 BPSG Nitride Sematech AEC/APC Symposium X - 19 - --Oxide --- Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - Chamber monitoring of product wafers: electron collision rate Electron collision rate - decreases with rf hours - very sensitive to etch chemistry Pr 1 Pr 2 ! One point one wafer Sematech AEC/APC Symposium X - 20 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - Chamber monitoring on product wafers: electron density Electron density - decreases with rf hours slightly - sensitive to etch chemistry One point one wafer Sematech AEC/APC Symposium X - 21 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - Chamber monitoring on product wafers: bulk power Bulk power - decreases with rf hours - very sensitive to power input - nearly not sensitive to etch chemistry One point one wafer Sematech AEC/APC Symposium X - 22 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - Chamber monitoring on blanket BPSG wafers - Electron collision rate correlates with uniformity. - Electron density and bulk power too Sematech AEC/APC Symposium X - 23 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: Conditioning after wet clean Wetclean Stable chamber conditions after about 10 wafers. Sematech AEC/APC Symposium X - 26 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Mx. P+: CT etch - short term chamber drift depending on idle time Electrical failure counts at Contact etch Bad chamber Wafer - Collision rate shows dependence on chamber idle time. - Constant chamber conditions after about 40 min. - Change in electron collision rate corresponds to change in electrical failure counts. Sematech AEC/APC Symposium X - 27 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES e. Mx. P+: Arcing detection Arcing between e - chuck and wafer Sematech AEC/APC Symposium X - 29 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Summary - Al etch in LAM TCP 9600 SE, oxide and nitride etch in Applied Materials Centura Mx. P+ have been monitored with HERCULES. - The measured parameters depend significantly on chamber conditions and etch results. - The masured parameters are absolute values. - No difficult modeling by the user is necessary, results are immediate. Sematech AEC/APC Symposium X - 31 - Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
Plasma etch control by HERCULES Applications of the tool - Development and optimizing processes Long and short term tool stability Tool matching Control of chamber cleaning Control of power coupling into plasma Endpoint detection Layer resolution Spatial resolution Reduction of test- and monitor wafers Detection of tool failure Arcing detection Sematech AEC/APC Symposium X - 32 - yes yes yes possible no yes yes Andreas Steinbach, Stefan Wurm, Christian Koelbl Ferdinand Bell, Daniel Koehler, Dirk Knobloch
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