eateto lcrclEgneigadCmue Sciences Computer and Engineering Electrical of Department

LSAPOESN NTE2S CENTURY 21ST THE IN PROCESSING PLASMA University of California, Berkeley nvriyo California of University ekly A94720 CA Berkeley, ..Lieberman M.A.

ci2My51 icpig23May05

P

L

A

S

M A

• • • • • • University of California, Berkeley Conclusions Standing frequencies low and high Decoupling discharges capacitive frequency Dual etching Plasma revolution nanoelectronics The aeand wave kneffects skin OUTLINE

ci2My52 icpig23May05

P

L

A

S

M A

• • • • • • • • • University of California, Berkeley 3 Crash mlong cm 3 Throw down break Never km/liter million 1 km/hr million 4 n2 er n optra oefla l those all as powerful as computer one performance years same 20 the In for cost in decrease 1959 500,000-fold since years 2 every doubling Transistors/chip H AOLCRNC REVOLUTION NANOELECTRONICS THE nSlcnVle today Valley Silicon in QIAETATMTV ADVANCE AUTOMOTIVE EQUIVALENT away × aday × ahrta a akn fees parking pay than rather mwide cm 1

ci2My53 icpig23May05

P

L

A

S

M A University of California, Berkeley H NETO FTETRANSISTOR THE OF INVENTION THE

ci2My54 icpig23May05

P

L

A

S

M A

IS NERTDCRUTADMICROPROCESSOR AND CIRCUIT INTEGRATED FIRST University of California, Berkeley

ci2My55 icpig23May05

P

L

A

S

M A

• • • University of California, Berkeley forever is exponential “No o efflligprophecy self-fulfilling growing) a size Now chip (1965) shrinking; Moore size Gordon (Transistor — months” 18 every double “Transistors/chip Gro or,2003) Moore, (Gordon

Transistors/Chip 10 10 10 10 10 10 10 10 10 1965 2 3 4 5 6 7 8 9 10 4004 1970 OR’ LAW MOORE’S 1975 8086 1980 ... ci2My56 icpig23May05 80286 2 yr doubling 1985 u ecndly‘forever”’ delay can we but III 1990 Year Pentium IV Pentium 1995 Pentium II Montecito 2000 2005 2010

2015

P

L

A

S

M A

• • • University of California, Berkeley ic): (desktop simulations from length gate Limiting Berkeley): – UC (FinFET, transistor CMOS fabricated Smallest – manufacture: In (2005): – art the years! of 20 State techniques another fabrication scaled ic be current can with CMOS built be can structures Both m(6aos aelength gate atoms) (16 nm 4 length gate atoms) (48 nm 12 thickness oxide gate atoms) (5 length nm gate 1.5 atoms) (200 nm 50 OBETIGT TRANSISTORS GATE DOUBLE/TRI

ci2My57 icpig23May05

P

L

A

S

M A

O EPRTR NUTILDISCHARGES INDUSTRIAL TEMPERATURE LOW University of California, Berkeley MHD power generation Electric power switch gear Electron and ion beam sources Arc lighting Fluorescent lamps Gas lasers Plasma displays Electricity sources Radiation Lighting, Architectural and automotive glass coatings Medical materials bio-compatibility treatments, sterilization, cleaning Textile adhesion treatments Food packaging permeability barriers Ceramics synthesis, ultrapure powders, nanopowders Metallurgical melting, refining, welding, cutting, hardening Aerospace and automotive ceramic and metal coatings, films, paints Liquid crystal display and solar cell depositions Microelectronics etching, deposition, oxidation, implantation, passivation plasma discharges Low temperature ci2My58 icpig23May05 Chemistry Plasma-assisted materials processing p < 1 Torr p > 1 Torr energy Mechanical Plasma thrusters

Heat

P

L

A

S

M A

University of California, Berkeley e thn o-nacdpam etching plasma Ion-enhanced etching Wet NSTOI ETCHING ANISOTROPIC ci2My59 icpig23May05

P

L

A

S

M A University of California, Berkeley species: reactive create to discharge Make 2. .Satwt nr oeua a CF gas molecular inert with Start 1. .Suc fanisotropy: of Source 5. Pump 4. .Seisrat ihmtra,yedn oaieproduct: volatile yielding material, with reacts Species 3. b la asvtn lsfo rnhbottom trench from bottom films trench passivating at Clear rate sidewalls: (b) reaction not etching but Increase bottom, (a) trench bombard ions Energetic wypro away EIEFRPAM ETCHING PLASMA FOR RECIPE duct Mask Si+4F CF 4 ci2My510 icpig23May05 −→ Ions Plasma −→ CF SiF 3 +F 4 4

↑

P

L

A

S

M A University of California, Berkeley ERATION GEN- THIRD ATION GENER- SECOND ERATION GEN- FIRST VLTO FECIGDISCHARGES ETCHING OF EVOLUTION ??

ci2My511 icpig23May05

P

L

A

S

M A H ULFEUNYCPCTV DISCHARGES? CAPACITIVE FREQUENCY DUAL WHY

• • • University of California, Berkeley frequency dual for Motivation discharge capacitive for Motivation rtclapiainfrdeeti etch dielectric for application critical A needn oto finflxadinenergy ion and flux ion of control Independent – (fluorine) dissociation of area Control large – over uniformity Robust – cost Low – o rqec otosinenergy ion controls flux frequency ion Low controls voltage frequency High

ci2My512 icpig23May05

P

L

A

S

M A

• • • • • University of California, Berkeley frequency High p R o frequency Low bobdpowers Absorbed ∼ ∼ 030mor C mTorr, 30–300 53 cm, 15–30 id 2eetoe)Tid 3electrodes) (3 Triode electrodes) (2 Diode YIA PRTN CONDITIONS OPERATING TYPICAL ~ ~ f L f V V l h l h ∼ ∼ – P – + + ∼ h –35 MHz, 2–13.56 – cm 1–3 ,P 4 27 F . l 8 –6 MHz, 1–160 /O ∼ ci2My513 icpig23May05 0–00W 500–3000 2 A feedstock /Ar V l V ∼ h 0–50V 500–1500 ∼ 0–0 V 200–500 ~ ~ V V l h

–

– + +

P

L

A

S

M A

• • • • University of California, Berkeley T temperature electron (once Make discharges these In idpneto lsadensity) plasma of (independent lcrnpwrblne= balance power Electron atceblne= balance Particle ω h 2 V OTO FPAM DENSITY PLASMA OF CONTROL h P  V e h oe bobdb electrons by absorbed power = ω otospam est influx) (ion density plasma controls l 2 V ⇒ l lcrntmeaueT temperature electron = = ⇒ ⇒ ⇒ ci2My514 icpig23May05 n T n lsadensity plasma e e ∝ ∼ ∝ sknown) is – eV 2–6 P ω e 2 V rf e n ∝ ω 2 V

rf

P

L

A

S

M A

• • • University of California, Berkeley Make obndcniinfridpnetcnrlo o u n energy and flux ion of control independent for condition Combined .HC i,JK e,adJW Shon, J.W. and Lee, Turner, J.K. M.M. Kim, and H.C. Rax 2. J.M. Booth, J.P. Kim, J. Lieberman, M.A. 1. o obrigeeg sttld isvlaears sheath across voltage bias dc total is energy bombarding Ion .PC ol,AR ligo,adMM Turner, M.M. and Ellingboe, A.R. Boyle, P.C. 3. EIO oe thn ypsu,p 3(2003) 23 p. Symposium, Etching Korea SEMICON 37 9 (2004) 697 , V l  V OTO FINENERGY ION OF CONTROL h V l otosinenergy ion controls ω ω E i h l 2 2 ci2My515 icpig23May05 ∼|  V V V h h l + hs Plasmas Phys.  V l 1 | .Py.D pl Phys. Appl. D: Phys. J. 10

55(2003) 4545 ,

P

L

A

S

M A

• • • • • University of California, Berkeley areas (plate diode Asymmetric l ihadlwfeunyhaigterms heating frequency balance low power and ion high and All electron and balance, particle Ion sheaths homogeneous frequency High sheaths law Child frequency Low LBLMDLO DISCHARGE OF MODEL GLOBAL ~ ~ V V – + l h – + ( ( ω ω h l ) ) ci2My516 icpig23May05 L A a and A A a b A b ) s al s ah s bh s

bl

P

L

A

S

M A

• University of California, Berkeley A a 4 cm 544 = u o perfect not but good is decoupling frequency high/low The

Eia (V) 1000 1200 1400 -3 200 400 600 800

n0 (m ) MHz 60/2 AND 27.1/2 FOR RESULTS 10 15 0 0 5 0 0 x 10 f h 16 100 100 =27 2 , 200 200 A

P P

h h (W) (W) 300 300 b . MHz 1

V V V V

0 cm 707 =

l l l l

=1800 V =1500 V =1200 V = 900 V 400 400 500 500 ci2My517 icpig23May05 2 , L =1 . cm, 6 u o perfect not but better is decoupling frequency high/low The Eia (V)

1000 1200 -3

200 400 600 800 n0 (m ) 0.5 1.5 0 0 1 2 0 0 x 10 f p 17 h 9 Tr argon mTorr 190 = 0MHz 60 = 100 100

P P

h h (W) (W)

V V V V

200 200

l l l l =1800 V =1500 V =1200 V = 900 V

300 300

P

L

A

S

M A

• University of California, Berkeley density ion uniform nearly over oscillates sheath frequency High .DA RQEC TCATCHEATING? STOCHASTIC FREQUENCY DUAL 1. Wall High frequency homogeneous Leemn 98 Leemn 98 (Kaganovich, 2002) (Lieberman, 1988) (Lieberman, 1988) Stochastic sheath motion heating S stoc S = 0 Wall Bulk plasma Electrons Ions Wall heating??? Stochastic Dual frequency High frequency Child law ci2My518 icpig23May05 sheath motion sheath Stochastic heating stoc ≠ 0S Ions near-homogeneous High frequency Electrons sheath motion osElectrons Ions Bulk plasma Bulk plasma Wall High frequency step model Stochastic heating sheath motion stoc ≠ 0 Bulk plasma Electrons

Ions

P

L

A

S

M A

• • • University of California, Berkeley networks? matching through driven systems Real sheaths? law discharges? Voltage-driven Child for term Cross urn-rvnhmgnosmdlgives model homogeneous Current-driven diieassumption? Additive os aefrcosemis crossterm for case Worst .CULN FVOLTAGES? OF COUPLING 2. E i = 3 8 E   i ci2My519 icpig23May05 ≈ V 6 1 l ( 0 + V . 1( 41 l V + h V V − l h + rs term cross when ) 3 2 V V h l V ) + l V h V V h l   = V

h

P

L

A

S

M A

• • University of California, Berkeley discharges frequency dual For hc ore upyteinpwr Is power? ion the supply sources Which supplies source frequency High ⇒ o igefeunycpctv discharges capacitive frequency single For Fpwrsuc supplies source power RF .INPWRSPLE YSOURCES? BY SUPPLIED POWER ION 3. lcrnpwr= power Electron lcrnpwr= power Electron o oe = power Ion o oe = power Ion ci2My520 icpig23May05 P P P P i e P i e ∝ ∝ e ∝ ∝ P ω and ω e ω ω 2 h 2 2 V 2 V V V h h P rf rf 2 ( ∝ i V ∝ ∝ l P n + nV n il /P V rf h ) ih   = P P V e e l /V h

?

P

L

A

S

M A

• University of California, Berkeley sheath across time transit period/ion bias rf on depends IEDF Power Bias RPEFEUNYR DISCHARGE RF FREQUENCY TRIPLE ~ ~ ~ V V V h l – + l 1 2 – – + + (60–160 MHz) Ions (1 MHz) (13.6 MHz) ci2My521 icpig23May05

f(E)

ounadKy(1972) Kay and Coburn

E 1

∆

E

i

E

2

P

L E

A

S

M A .S hno,D omn ..Yn,A aesn n .Holland, J. University of California, Berkeley and Paterson, A. Yang, J.G. Hoffman, D. Shannon, S. 3. .JK e,OV aulno ..Bbea ..Km n ..Shon, J.W. and Kim, H.C. Babaeva, N.Y. Manuilenko, O.V. Gijbels, Lee, R. J.K. and 2. Bogaerts, A. Georgieva, V. 1. umte to submitted lsaSucsSi Technol. Sci. Sources Plasma IT FINEEG DISTRIBUTION ENERGY ION OF WIDTH

Ion energy width

Ion energy maximum 10 bias, rf V 600 (Argon, 0.00 0.25 0.50 0.75 1.00 1.25 . . . . . 2.5 2.0 1.5 1.0 0.5 0.0 ora fApidPhysics Applied of Journal simulations x RF bias period/ion transit time across sheath 13.56 MHz theory ci2My522 icpig23May05 14 theory 9(2005) 89 , x 1 MHz 11 cm My2005) (May hs e.E Rev. Phys. − 3 density) 69

246(2004) 026406 ,

P

L

A

S

M A

IHFEUNYEETOANTCEFFECTS ELECTROMAGNETIC FREQUENCY HIGH

• • • University of California, Berkeley electro- equations on Maxwell based of set mostly full discharges not capacitive statics, of studies Previous frequency High ..Leemn ..Boh .Caet ..Rx n ..Turner, M.M. and Rax, J.M. Chabert, P. Booth, J.P. Lieberman, M.A. ihfeunyadlrearea large and frequency High lsaSucsSi Technol. Sci. Sources Plasma = ⇒ ⇒ ostanding no ihdensity high ci2My523 icpig23May05 11 aeor wave ⇒ ⇒ 8 (2002) 283 , standing kneffects skin kneffects skin wave

effects

P

L

A

S

M A

2 uwr wave Outward (2) (1) University of California, Berkeley V s xie ailyoutward radially excites YIDIA AAIIEDISCHARGE CAPACITIVE CYLINDRICAL osdrol h ihfeunysource frequency high the only Consider ilscno astruhmtlplates metal through pass cannot Fields xie ailyinward radially excites – ~ V h Sheath Sheath Plasma + ci2My524 icpig23May05 2 aei o v top in wave R z r aein wave cu gap acuum plasma s s 2 d 2

l

P

L

A

S

M A

• • • • • University of California, Berkeley with modes TM hoesm nfr density uniform some Choose equations Maxwell’s where lsai wal)lsydeeti slab dielectric lossy (weakly) is Plasma ov ihaporaebudr conditions boundary appropriate with Solve ω ν m p =( lcrnnurlcliinfrequency collision electron-neutral = e 2 1 r n ∂ ∂H e ∂z ( / rH ∂r H φ 0 m φ φ = ) AI PHYSICS BASIC ∼ ) ∂E 1 − = ∂z / κ e 2 jω jωt p r jω lsafrequency plasma = =1 ci2My525 icpig23May05 − 0 0 κ ∂E κ p ∂r − n p E E e z r ω z n hahwidth sheath and = ( ω − − ω idciefield) (inductive jωµ p 2 cpctv field) (capacitive jν m 0 H ) φ

s

P

L

A

S

M A

• • • • University of California, Berkeley also are There Radial with xa kndphfrsurface for depth skin Axial oe en Power λ 0 aeeghfrsurface for wavelength = estepam i a via plasma the ters c/f (weak) Decay Decay h respace free the vnsetmodes evanescent UF C AEMODE WAVE SURFACE δ Standing wave λ ufc aeMode Wave Surface λ ≈ ci2My526 icpig23May05

wave: wavelength δ Plasma 1+ ae(low wave ufc aemode: wave surface λ ∼ 0 edn oeg ffcsnear effects edge to leading d/s ω c p ∼ est limit): density λ 3 0 s 2 s

d

P

L

A

S M

r A = R OE EOIINVRU AISA 35 MHz 13.56 AT RADIUS VERSUS DEPOSITION POWER • • Power/area

0.5 University of California, Berkeley P R 0 1 02550 cap 0cm, 50 = (dash), kneffects skin and wave ing stand- Small δ n e =16 d =10 P cm, 2 = ind r (cm) . 7cm 9 dt and (dot) cm Total Inductive Capacitive − s 3 =0 effect Edge ci2My527 icpig23May05 . P 4cm( tot sld safnto of function a as (solid) Power/area λ 0.5 0 1 02550 ≈ –0m) 9–10 δ n fect ef- skin Large e Inductive =5 =10 r (cm) . 3cm 10 Capacitive Total cm

r

P L −

effect Edge A

3

S

M A OE EOIINVRU AISA 07MHz 40.7 AT RADIUS VERSUS DEPOSITION POWER • • Power/area

0.5 University of California, Berkeley P R 0 1 02550 cap 0cm, 50 = (dash), fect ef- wave ing stand- Large δ n e =15 d =10 P cm, 2 = ind r (cm) . 9cm 9 dt and (dot) Capacitive cm Inductive Total − s 3 =0 effect Edge ci2My528 icpig23May05 . P 4cm( tot sld safnto of function a as (solid) Power/area λ 0.5 0 1 02550 ≈ 3m) et cancel fects ef- skin and Standing δ n e =6 =7 Capacitive r (cm) . 3cm Total × 10 wave 9 r

Inductive

P cm

L A

effect Edge S

− M

3 A

XEIETLRSLSFRSADN WAVES STANDING FOR RESULTS EXPERIMENTAL University of California, Berkeley A ert .Caet - ot,J ol,J ulo n h Auvray, Ph. and Guillon J. Jolly, J. Booth, J-P Chabert, P. Perret, (A. pl hs Lett. Phys. Appl. ci2My529 icpig23May05 83 4,2003) 243, , t8.6MHz 81.36 at MHz pronounced 60 more is at and seen is fect standing The 50Wrfpowerp 20 5 mTorr 150 = × 0c discharge cm 20

aeef- wave

P

L

A

S

M A •

Midplane University of California, Berkeley density (in determine local to with balance model energy line transmission plane Parallel .Caet ..Ribut ..Rx n ..Lieberman, M.A. and Rax, J.M. Raimbault, J.L. Chabert, P. x = 0 λ/λ hs Plasmas Phys. 0 ≈ 40 RNMSINLN MODELS LINE TRANSMISSION V – V + rf 1 / I 10 11 L 75(2004) 1775 , − 1 / 2 f − ci2My530 icpig23May05 x Edge 2 = / 5 x 0 ~ – + V rf n V e + – ( x ( Y'=G'(V)+j ) x n hahwidth sheath and ) hahcpctneIon energy loss Sheath capacitance Z' = j ω C'(V) ω L' dx x atceand particle )

Ohmic heating Plasma inductance Stochastic heating

P

L

A

S M

s A m ( x ) .Caet ..Ribut ..Rx n .Perret, A. and Rax, J.M. Raimbault, J.L. Chabert, Schmitt, P. J. and Sansonnens L.

• • • University of California, Berkeley standing eliminate plate) diel (and electrode Shaped h lcrd hp saGusa,idpneto h lsaprop- plasma the of independent Gaussian, a erties is shape electrode voltage The keeps constant edge section to discharge compared across center in thickness overall Increased UPESO FSADN AEEFFECTS WAVE STANDING OF SUPPRESSION pl hs Lett. Phys. Appl. ci2My531 icpig23May05 82 8 (2003) 182 , hs Plasmas Phys. wave 11

01(2004) 4081 ,

P

L

A effects

S

M A

• University of California, Berkeley W 50–300 argon, mTorr 5–250 XEIETLCONFIRMATION EXPERIMENTAL .Shite al, et Schmitt H. .Ap.Phys. Appl. J. ci2My532 icpig23May05 95

59(2004) 4559 ,

P

L

A

S

M A

• • University of California, Berkeley Lieberman, M.A. and Rax, J.M. Levif, P. Raimbault, J.L. Chabert, P. 2. oto fsi effects? skin of Control R d δ .MA ibra,JP ot,P hbr,JM a,adMM Turner, M.M. and Rax, J.M. Chabert, P. Booth, J.P. Lieberman, M.A. 1. kneet = effects Skin ∝ ukpam half-thickness plasma bulk = icag radius discharge = umte to submitted lsaSucsSi Technol. Sci. Sources Plasma √ 1 n olsoa rcliinessi depth skin collisionless or collisional = ⇒ hsc fPlasmas, of Physics ailnnnfriisa ihdniiswhen densities high at nonuniformities radial KNEFFECTS? SKIN δ ci2My533 icpig23May05 < ∼ 0 11 . 45 8 (2002) 283 , √ a 2005 May

dR

P

L

A

S

M A

• • • • • • University of California, Berkeley century! 21st the in future bright a has processing Plasma h ihadlwfeuniscnb well-decoupled be Standing can frequencies low and high for The important increasingly are etching dielectric reactors next-generation capacitive frequency discharges Dual processing of development lengths the drives gate 4nm–12nm Nanoelectronics — nano-sizes to scale will Transistors wave ffcscnb controlled be can effects CONCLUSIONS

ci2My534 icpig23May05

P

L

A

S

M A