EDGE EFFECTS IN REACTIVE ION ETCHING: THE WAFER- FOCUS RING GAP* Natalia Yu. Babaeva and Mark J. Kushner Iowa State University Department of Electrical.

Slides:

Advertisements

Similar presentations

NARROW GAP ELECTRONEGATIVE CAPACITIVE DISCHARGES AND STOCHASTIC HEATING M.A. Lieberman Department of Electrical Engineering and Computer Sciences University.

Advertisements

PLASMA ETCHING OF EXTREMELY HIGH ASPECT RATIO FEATURES:

REACTION MECHANISM AND PROFILE EVOLUTION FOR CLEANING AND SEALING POROUS LOW-k DIELECTRICS USING He/H 2 AND Ar/NH 3 PLASMAS Juline Shoeb a) and Mark J.

CONTROL OF ELECTRON ENERGY DISTRIBUTIONS AND FLUX RATIOS IN PULSED CAPACITIVELY COUPLED PLASMAS* Sang-Heon Song a) and Mark J. Kushner b) a) Department.

CONTROL OF ELECTRON ENERGY DISTRIBUTIONS IN INDUCTIVELY COUPLED PLASMAS USING TANDEM SOURCES* Michael D. Logue (a), Mark J. Kushner (a), Weiye Zhu (b),

POLYMERISATION PROCESSES IN LOW-PRESSURE FLUOROCARBON PLASMAS

MODELING OF H 2 PRODUCTION IN Ar/NH 3 MICRODISCHARGES Ramesh A. Arakoni a), Ananth N. Bhoj b), and Mark J. Kushner c) a) Dept. Aerospace Engr, University.

OPTIMIZING THE PERFORMANCE OF PLASMA BASED MICROTHRUSTERS* Ramesh A. Arakoni, a) J. J. Ewing b) and Mark J. Kushner c) a) Dept. Aerospace Engineering University.

MULTISCALE SIMULATION OF FUNCTIONALIZATION OF SURFACES USING ATMOSPHERIC PRESSURE DISCHARGES * Ananth N. Bhoj a) and Mark J. Kushner b) a) Department of.

NUMERICAL INVESTIGATION OF WAVE EFFECTS IN HIGH-FREQUENCY CAPACITIVELY COUPLED PLASMAS* Yang Yang and Mark J. Kushner Department of Electrical and Computer.

EFFECT OF PRESSURE AND ELECTRODE SEPARATION ON PLASMA UNIFORMITY IN DUAL FREQUENCY CAPACITIVELY COUPLED PLASMA TOOLS * Yang Yang a) and Mark J. Kushner.

SiO 2 ETCH PROPERTY CONTROL USING PULSE POWER IN CAPACITIVELY COUPLED PLASMAS* Sang-Heon Song a) and Mark J. Kushner b) a) Department of Nuclear Engineering.

RECIPES FOR PLASMA ATOMIC LAYER ETCHING*

FUNCTIONALIZATION OF SURFACES BY PLASMAS AT LOW AND HIGH PRESSURE* Ananth N. Bhoj, a) Natalia Babaeva, b) and Mark J. Kushner b) a) Dept. of Chemical and.

ISPC 2003 June , 2003 Consequences of Long Term Transients in Large Area High Density Plasma Processing: A 3-Dimensional Computational Investigation*

WAVE AND ELECTROSTATIC COUPLING IN 2-FREQUENCY CAPACITIVELY COUPLED PLASMAS UTILIZING A FULL MAXWELL SOLVER* Yang Yang a) and Mark J. Kushner b) a) Department.

FLUORINATION WITH REMOTE INDUCTIVELY COUPLED PLASMAS SUSTAINED IN Ar/F 2 AND Ar/NF 3 GAS MIXTURES* Sang-Heon Song a) and Mark J. Kushner b) a) Department.

FACTORS AFFECTING THE SEALING EFFICIENCY OF LOW-k DIELECTRIC SURFACE PORES USING SUCCESSIVE He AND Ar/NH 3 PLASMA TREATMENTS Juline Shoeb a) and Mark J.

SiO 2 ETCH RATE AND PROFILE CONTROL USING PULSE POWER IN CAPACITIVELY COUPLED PLASMAS* Sang-Heon Song a) and Mark J. Kushner b) a) Department of Nuclear.

University of Illinois Optical and Discharge Physics ETCH PROFILES IN SOLID AND POROUS SiO 2  Solid  Porosity = 45 % Pore radius = 10 nm  Porous SiO.

THE WAFER- FOCUS RING GAP*

PLASMA DISCHARGE SIMULATIONS IN WATER WITH PRE-EXISTING BUBBLES AND ELECTRIC FIELD RAREFACTION Wei Tian and Mark J. Kushner University of Michigan, Ann.

WAFER EDGE EFFECTS CONSIDERING ION INERTIA IN CAPACITIVELY COUPLED DISCHARGES* Natalia Yu. Babaeva and Mark J. Kushner Iowa State University Department.

PLASMA ATOMIC LAYER ETCHING*

MAGNETICALLY ENHANCED MULTIPLE FREQUENCY CAPACITIVELY COUPLED PLASMAS: DYNAMICS AND STRATEGIES Yang Yang and Mark J. Kushner Iowa State University Department.

 Poisson’s equation, continuity equations and surface charge are simultaneously solved using a Newton iteration technique.  Electron energy equation.

STREAMER DYNAMICS IN A MEDIA CONTAINING DUST PARTICLES* Natalia Yu. Babaeva and Mark J. Kushner Iowa State University Department of Electrical and Computer.

SURFACE MODIFICATION OF POLYMER PHOTORESISTS TO PROTECT PATTERN TRANSFER IN FLUOROCARBON PLASMA ETCHING* Mingmei Wanga) and Mark J. Kushnerb) a)Iowa State.

LOW-k DIELECTRIC WITH H2/He PLASMA CLEANING

University of Illinois Optical and Discharge Physics SPEED AND SELECTIVITY: CUSTOM WAVEFORMS 200 V (Slow, selective) MASK SiO 2 Si  15 mTorr, Ar/C 4 F.

INVESTIGATIONS OF MAGNETICALLY ENHANCED RIE REACTORS WITH ROTATING (NON-UNIFORM) MAGNETIC FIELDS Natalia Yu. Babaeva and Mark J. Kushner University of.

MODELING OF MICRODISCHARGES FOR USE AS MICROTHRUSTERS Ramesh A. Arakoni a), J. J. Ewing b) and Mark J. Kushner c) a) Dept. Aerospace Engineering University.

AVS 2002 Nov 3 - Nov 8, 2002 Denver, Colorado INTEGRATED MODELING OF ETCHING, CLEANING AND BARRIER COATING PVD FOR POROUS AND CONVENTIONAL SIO 2 IN FLUOROCARBON.

MODELING OF MICRODISCHARGES FOR USE AS MICROTHRUSTERS Ramesh A. Arakoni a), J. J. Ewing b) and Mark J. Kushner c) a) Dept. Aerospace Engineering University.

Aspect Ratio Dependent Twisting and Mask Effects During Plasma Etching of SiO2 in Fluorocarbon Gas Mixture* Mingmei Wang1 and Mark J. Kushner2 1Iowa State.

STREAMER INITIATION AND PROPAGATION IN WATER WITH THE ASSISTANCE OF BUBBLES AND ELECTRIC FIELD INITIATED RAREFACTION Wei Tian a) and Mark J. Kushner b)

PLASMA ATOMIC LAYER ETCHING USING CONVENTIONAL PLASMA EQUIPMENT*

OPTIMIZATION OF O 2 ( 1  ) YIELDS IN PULSED RF FLOWING PLASMAS FOR CHEMICAL OXYGEN IODINE LASERS* Natalia Y. Babaeva, Ramesh Arakoni and Mark J. Kushner.

SIMULATION OF POROUS LOW-k DIELECTRIC SEALING BY COMBINED He AND NH 3 PLASMA TREATMENT * Juline Shoeb a) and Mark J. Kushner b) a) Department of Electrical.

VUV PHOTON SOURCE OF A MICROWAVE EXCITED MICROPLASMAS AT LOW PRESSURE*

EFFECT OF BIAS VOLTAGE WAVEFORMS ON ION ENERGY DISTRIBUTIONS AND FLUOROCARBON PLASMA ETCH SELECTIVITY* Ankur Agarwal a) and Mark J. Kushner b) a) Department.

TRIGGERING EXCIMER LASERS BY PHOTOIONIZATION FROM A CORONA DISCHARGE* Zhongmin Xiong and Mark J. Kushner University of Michigan Ann Arbor, MI USA.

Yiting Zhangb, Mark Denninga, Randall S. Urdahla and Mark J. Kushnerb

Why plasma processing? (1) UCLA Accurate etching of fine features.

SPACE AND PHASE RESOLVED MODELING OF ION ENERGY ANGULAR DISTRIBUTIONS FROM THE BULK PLASMA TO THE WAFER IN DUAL FREQUENCY CAPACITIVELY COUPLED PLASMAS*

SiO2 ETCH PROPERTIES AND ION ENERGY DISTRIBUTION IN PULSED CAPACITIVELY COUPLED PLASMAS SUSTAINED IN Ar/CF4/O2* Sang-Heon Songa) and Mark J. Kushnerb)

ATMOSPHERIC PRESSURE PLASMA TRANSFER OF JETS AND BULLETS ACROSS DIELECTRIC TUBES AND CHANNELS* Zhongmin Xiong (a), Eric Robert (b), Vanessa Sarron (b)

FLCC March 28, 2005 FLCC - Plasma 1 Fluid Modeling of Capacitive Plasma Tools FLCC Presentation March 28, 2005 Berkeley, CA David B. Graves, Mark Nierode,

EXCITATION OF O 2 ( 1 Δ) IN PULSED RADIO FREQUENCY FLOWING PLASMAS FOR CHEMICAL IODINE LASERS Natalia Babaeva, Ramesh Arakoni and Mark J. Kushner Iowa.

Plasma Etch Sub-processes. Reactant Generation process Substrate Dissociation/ ionization of input gases by plasma Gas delivery RF Electrode During ionization,

DEVELOPMENT OF ION ENERGY ANGULAR DISTRIBUTION THROUGH THE PRE-SHEATH AND SHEATH IN DUAL-FREQUENCY CAPACITIVELY COUPLED PLASMAS* Yiting Zhanga, Nathaniel.

CONTROL OF ELECTRON ENERGY DISTRIBUTIONS THROUGH INTERACTION OF ELECTRON BEAMS AND THE BULK IN CAPACITIVELY COUPLED PLASMAS* Sang-Heon Song a) and Mark.

DRY ETCHING OF Si 3 N 4 USING REMOTE PLASMA SOURCES SUSTAINED IN NF 3 MIXTURES* Shuo Huang and Mark J. Kushner Department of Electrical Engineering and.

PROPERTIES OF UNIPOLAR DC-PULSED MICROPLASMA ARRAYS AT INTERMEDIATE PRESSURES* Peng Tian a), Chenhui Qu a) and Mark J. Kushner a) a) University of Michigan,

Consequences of Implanting and Surface Mixing During Si and SiO 2 Plasma Etching* Mingmei Wang 1 and Mark J. Kushner 2 1 Iowa State University, Ames, IA.

Reaction Mechanism and Profile Evolution for HfO2 High-k Gate-stack Etching: Integrated Reactor and Feature Scale Modeling* Juline Shoeba) and Mark J.

HIGH FREQUENCY CAPACITIVELY COUPLED PLASMAS: IMPLICIT ELECTRON MOMENTUM TRANSPORT WITH A FULL-WAVE MAXWELL SOLVER* Yang Yang a) and Mark J. Kushner b)

PLASMA DYNAMICS AT THE IONIZATION FRONT OF HIGH

University of Michigan, Ann Arbor, MI, 48109, USA

Yiting Zhang and Mark J. Kushner

SUPPRESSING NONLINEARLY-DRIVEN INHOMOGENEITIES IN HIGH FREQUENCY CCP’s

Sang-Heon Songa) and Mark J. Kushnerb)

ENGINEERING THE FOCUS RING*

Amanda M. Lietz, Seth A. Norberg, and Mark J. Kushner

Flux and Energy of Reactive Species Arriving at the Etch Front in High Aspect Ratio Features During Plasma Etching of SiO2 in Ar/CF4/CHF3 Mixtures* Soheila.

SURFACE CORONA-BAR DISCHARGES

CONTROL OF ION ACTIVATION ENERGY TO SURFACES IN ATMO-

ION ENERGY DISTRIBUTIONS TO PARTICLES IN CORONA DISCHARGES

BREAKDOWN CHARACTERISTICS

Presentation transcript:

EDGE EFFECTS IN REACTIVE ION ETCHING: THE WAFER- FOCUS RING GAP* Natalia Yu. Babaeva and Mark J. Kushner Iowa State University Department of Electrical and Computer Engineering Ames, IA 50011, USA AVS 53 rd International Symposium November 2006 * Work supported by Semiconductor Research Corp. and NSF AVS2006_Natalie_01

Iowa State University Optical and Discharge Physics AGENDA AVS2006_Natalie_02  Wafer edge effects  Description of the model  Penetration of plasma into wafer-focus ring gaps in Ar/CF 4 CCPs  Gap width  Focus ring conductivity  Focus ring height  Concluding remarks

Iowa State University Optical and Discharge Physics WAFER EDGE EFFECTS  Gap (< 1 mm) between wafer and focus ring in plasma tools is for mechanical clearance.  The wafer is often beveled at edge allowing for “under wafer” plasma-surface processes. AVS2006_Natalie_03  Penetration of plasma into gap can lead to deposition of contaminating films and particles.

PENETRATION OF PLASMA INTO WAFER- FOCUS RING GAP Iowa State University Optical and Discharge Physics AVS2006_Natalie_04  Penetration of plasma into wafer-focus ring gap was computationally investigated for a capacitively coupled discharge for polymerizing (Ar/CF 4 ) conditions.  2-dimensional model using an unstructured mesh use used to resolve multiple scale lengths.  Improvements to algorithms to revolve on momentum into gaps were made.

nonPDPSIM CHARGED PARTICLE TRANSPORT  Poisson equation: electric potential  Transport of charged species j  Surface charge balance  Full momentum for ion fluxes  Transport of secondary electrons from biased substrate is addressed with a Monte Carlo simulation.  Neutral transport addressed with Navier-Stokes equations. AVS2006_Natalie_05 Iowa State University Optical and Discharge Physics

Iowa State University Optical and Discharge Physics SURFACE-KINETICS-MODULE (SKM)  SKM uses fluxes to surface to produce coverage of surface species, sticking coefficients and returning fluxes to the plasma.=  For demonstration purposes, a simple polymer depositing reaction mechanism.  Neutral deposition CF n on surfaces W producing multiple layers of polymer Poly n  Ion sputtering of polymer to generate CF n AVS2006_Natalie_06

MESHING TO RESOLVE FOCUS RING GAP Iowa State University Optical and Discharge Physics AVS2006_Natalie_07  Unstructured meshes resolve wafer-focus ring gaps of < 1 mm.

POTENTIAL, E- FIELD, ELECTRONS Iowa State University Optical and Discharge Physics  High electric field heats electrons in the sheath regions.  Off-axis maximum in [e] consequence of focus ring- uncorrelated to gap.  Ar/CF 4 = 97/03, 10MHz, 90 mTorr, 300 V, 300 sccm MIN MAX AVS2006_Natalie_08 [e] E/n [T e ] Pot

POSITIVE AND NEGATIVE IONS Iowa State University Optical and Discharge Physics  Discharge is highly electronegative.  In spite of non- uniform [e], positive ion fluxes are fairly uniform as [M + ] > [e].  Ar/CF 4 = 97/03, 10MHZ, 90 mTorr, 300 V, 300 sccm MIN MAX Log scale AVS2006_Natalie_09 [Ar + ] [CF 3 + ] [CF 3 - ] [F - ]

Iowa State University Optical and Discharge Physics  Dominant neutral polymerizing radical is CF 2.  Sheaths are many mm thick which is important factor in penetration of plasma into gaps.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm AXIAL DENSITIES AVS2006_Natalie_10

Iowa State University Optical and Discharge Physics MIN MAX Log scale  Electron penetration into gaps in anode portion of cycle is nominal due to surface charging and sheath formation.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm ELECTRON PENETRATION INTO GAP AVS2006_Natalie_11a  1.0 mm Gap  0.25 mm Gap Animation Slide

Iowa State University Optical and Discharge Physics MIN MAX Log scale  Electron penetration into gaps in anode portion of cycle is nominal due to surface charging and sheath formation.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm ELECTRON PENETRATION INTO GAP AVS2006_Natalie_11b  1.0 mm Gap  0.25 mm Gap

Iowa State University Optical and Discharge Physics MIN MAX Log scale  Ions penetrate into larger gap throughout the rf cycle whose size is commensurate with sheath width. Smaller gap receives only nominal flux.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm Ar + PENETRATION INTO GAP AVS2006_Natalie_12a  1.0 mm Gap  0.25 mm Gap Animation Slide

Iowa State University Optical and Discharge Physics MIN MAX Log scale  Ions penetrate into larger gap throughout the rf cycle whose size is commensurate with sheath width. Smaller gap receives only nominal flux.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm Ar + PENETRATION INTO GAP AVS2006_Natalie_12b  1.0 mm Gap  0.25 mm Gap

Iowa State University Optical and Discharge Physics ION PENETRATION vs GAP SIZE AVS2006_Natalie_13  Ion penetration into gap critically depends on size relative to sheath.  Gaps ≥ sheath thickness allow penetration.  NOTE! High plasma density tools produce smaller sheaths and more penetration.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm

Iowa State University Optical and Discharge Physics 0.5 mm GAP: FLUXES ALONG SURFACES  Decrease of ion flux into gap is greater than decrease of neutral radical fluxes.  Negative charging of dielectric focus ring and redirection of ions helps deplete fluxes. AVS2006_Natalie_14  Ions  Radicals  Ar/CF 4 =97/03, 90 mTorr

Iowa State University Optical and Discharge Physics 0.5 mm GAP: POLYMER DEPOSITION  Lack of ion sputtering of polymer in gap results in disproportionately large deposition.  100 decrease in radical flux produces only factor of 5 decrease in polymer.  Particle formation is likely to be greater. AVS2006_Natalie_15  Ar/CF 4 =97/03, 90 mTorr

Iowa State University Optical and Discharge Physics POLYMER DEPOSITION vs GAP SIZE AVS2006_Natalie_16  Ar/CF 4 =97/03, 90 mTorr  When increasing gap size… Under bevel:  More radical flux penetrates while ion flux is still small.  More deposition On pedestal:  View angle to plasma enables more ion flux.  Effects are not terribly large over this range of gaps.

Iowa State University Optical and Discharge Physics  Ions flux focuses on edges of wafer and focus ring: electric field enhancement and preferential negative charging.  Focusing into bevel of wafer increases with gap size.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm ION FOCUSING AVS2006_Natalie_17a  1.0 mm Gap  0.25 mm Gap Animation Slide

Iowa State University Optical and Discharge Physics  Ions flux focuses on edges of wafer and focus ring: electric field enhancement and preferential negative charging.  Focusing into bevel of wafer increases with gap size.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm ION FOCUSING AVS2006_Natalie_17b  1.0 mm Gap  0.25 mm Gap

Iowa State University Optical and Discharge Physics  Ion focusing is potentially harmful due to sputtering (etch block materials put into plasma) and erosion of pieces which reduces lifetime.  Tool design can greatly influence ion erosion.  Example: Extension of biased substrate under dielectric focus ring of differing conductivity. TOOL DESIGN: ION FOCUSING AVS2006_Natalie_18

Iowa State University Optical and Discharge Physics  Low conductivity ring charges more negatively during anodic part of cycle; and so more focuses ion fluxes.  High conductivity ring has less focusing but allows more ion flux into gap; lack of charging reduces radial E-field.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr ION FOCUSING vs RING CONDUCTIVITY AVS2006_Natalie_19a Animation Slide  0.1 Ohm -1 cm -1  Ohm -1 cm -1

Iowa State University Optical and Discharge Physics  Low conductivity ring charges more negatively during anodic part of cycle; and so more focuses ion fluxes.  High conductivity ring has less focusing but allows more ion flux into gap; lack of charging reduces radial E-field.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr ION FOCUSING vs RING CONDUCTIVITY AVS2006_Natalie_19b Animation Slide  0.1 Ohm -1 cm -1  Ohm -1 cm -1

PLASMA PENETRATION: HIGH FOCUS RING Iowa State University Optical and Discharge Physics  Shielding of plasma from gap by using tall ring intensifies focusing of ions into end of ring.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm AVS2006_Natalie_20a Animation slide MIN MAX Log scale

PLASMA PENETRATION: HIGH FOCUS RING Iowa State University Optical and Discharge Physics  Shielding of plasma from gap by using tall ring intensifies focusing of ions into end of ring.  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr, 300 V, 300 sccm AVS2006_Natalie_20b MIN MAX Log scale

Iowa State University Optical and Discharge Physics  Exposing underside of bevel by lowering focus ring allows deep ion penetration. AVS2006_Natalie_21  Ar/CF 4 = 97/03, 10 MHz, 90 mTorr MIN MAX Log scale PLASMA PENETRATION: LOW FOCUS RING

CONCLUDING REMARKS  Penetration of plasma into wafer-focus ring gap of an RIE discharge was computationally investigated.  Plasma penetration depends on size of gap relative to sheath thickness.  For test conditions (Ar/CF 4, 90 mTorr, 300 V, [M + ] = cm -3 ) significant penetration occurs for gap < 0.5 mm.  More penetration expected for high plasma densities.  Polymerization inside gap is magnified by reduction in ion sputtering.  Ion focusing into edges depends on gap size and tool design (e.g., conductivity of ring). Iowa State University Optical and Discharge Physics AVS2006_Natalie_21