CMP%20introduction%20%E2%80%930605%20blank-2.pdf

CMP IntroductionF14A TFE1

CMP Polish mechanism“Chemical Mechanical Polishing&

• CMP MechanismChemical1 2Mechanicl43

OxCMP MechanismsWCuHighly solublein water

CMP Polish mechanismPerston Model:CMP Key parameter :• Slurry flow rate (k)• Head down force(P)• Head/Platen RPM(ν)CMP Key Components :• Wafer• Slurry• Pad

Prestion’s Equation• Slurry typesMechanical slurry (Prestonian)Chemical slurry (Non-Prestonian)(Non-Prestonian Slurries ExhibitFast Rate Drop at Pressuresbelow Critical)

• Slurry-Pad-Wafer (Three-Body):• slurry pad• K :

• Pattern Wafer Polished behaviorP 2 P 1P 3P 2 P 1P 3P 1 >P 2 >P 3 ~0 P 1 >P 2 >P 3P P2 P 1 3 P 2 P 3 P 1P 1 >P 2 >P 3 >0 P 1 ≌ P 2 ≌P 3

• Mechanical effect:• RRCMP MechanismsCMP•RRdishing•

• Chemical effect:•• Cu Pourbaix diagramspHRRCMP MechanismspH 7~13RR NH 4 OHNH4OKN0 3- Fe(CN)3-6BTAH +CMPH 2 O 2

CMP Clean mechanism

Interaction Forces between Wafer and surfacePhysisorptionVan Der Waals ForcesElectrostatic AttractionChemisorptionChemical reaction betweenparticles and surfacesCapillary Condensation

• ChemicalCMP Cleaner Mechanisms••• (molecular adhesion)• (electrostatic interactions)• (liquid bridges)• (chemical bonding)spot)(Water•Citric Acid為 了 避 免 金 屬 腐 蝕 疑 慮 , 對 於 去 除金 屬 離 子 可 以 選 用 錯 合 劑(complexing reagent), 如 檸 檬酸 (citric acid), 可 以 鉗 合 金 屬 離子 形 成 穩 定 水 溶 性 錯 合 物 , 抑 制 其生 成 氫 氧 化 物 沈 積 。 如 表 一 所 示 ,經 由 檸 檬 酸 清 洗 後 鈣 、 鐵 、 銅 、 鋅等 金 屬 離 子 之 殘 留 量 大 幅 減 低

• MechanicalCMP Cleaner MechanismsVideo: Cleaner

Major Consumable PartsProperty

Slurry Property

Filter PropertyPore size

Pad :• slurry• &Pad Property••••• pad• PadIC1010PolitexSP2000 (Hard material)Suba TM IV (Soft material)

• Why need Pad condition• \ pad• padNo PCPC

Disk Property• Manufacturing method• Electroplating ( ) :physical ( )• Brazing( or ore-sintering);chemical&Physical ( )

• Disk Lifetime:Pad Property• Diskpadwafer remove ratewafer defect diskpad

CMP Requirementsand Major Defect

Cu CMP Requirements• No Cu Residue• Process ControlRepeatable endpointTotal Cu Loss• Defect reductionNo corrosionErosionDishingLEFT Blank CuCufor ConfidentialOxideDense Arrays Wide Lines(50% (>10µm)Pattern Density)Minimal micro-scratchesNo BTA and slurry residueOxide Loss• Minimal copper lossDishing in wide Cu linesOxide erosion in dense arraysAnti-dishing in special patternsTiger teeth • Electronic ControlContinuity and Rs meet targetFSG thicknessPattern density, Rs NU%• Throughput• Cost

How to control Process Performance?CMP only control remove amount , not remain thicknessTotal remove amountOx lossLEFT Blankfor ConfidentialR.R. mode(APC)Endpoint modeTime modeSTI/ILDW/Cu EbaraCu AMAT

Advance Process Control model evolutionAPC(LtL)Etch to CMP(LtL)Pad/Tool offsetAPCEPA, RRBy Zone APC(WiW)SCDSCDPostLEFTmeasBlankThicknessPost EtchBy Lot Mean Wafer Meanfor ConfidentialAPCPad/Tool offsetTrench offsetIM-CLC(WtW)EPA, RRSCDPost CMPWafer MeanModel BuilderSCDIM-NOVASCDIM-NOVAPost Etch by SitePost CMPBy SitePost Etch(VM)Wafer MeanPost CMPWafer MeanAPCPad/Tool offsetEPA, RRModel BuilderAPCPad/Tool offsetEPA, RRModel BuilderTrench offsetTrench offset

APC• RAremove amount•• RR remove rate• C/W monitorRA ( A )Polish TIME (s) =RR ( A /s )• EPA Equivalent Polish Amount• C/W

APC skeleton前 量 測 DATA後 量 測 DATAMetrologyPre Process tool前 量 測 DATAProcess toolLEFT BlankChamber RRfor ConfidentialPolish timeIMCLCAuto RWKClose loop controlTAPEPAPolish TIME =ChamberRREPARR / 60

CMP Fundamental-Dishing & Erosion• Slurry property• Selectivity• Inhibitor• Pad property• Hardness• Elastic deformationElasticHardnessSelectivityDishingErosionWide Lines(>10µm)Dense Arrays(50% Pattern Density)

Minimal Cu LossCleared Wafer RegionsErosionDishingUn-Cleared Wafer RegionsOver-polish RequiredCu FieldBarrierPatternedSubstrate‣ Endpoint signalbased on wafercenter will result insignificant dishingand erosion atwafer edge duringCu over-polish

CMP Defect Overview• CMP Related Defectivity: Scratching. Slurry Residues. Corrosion. Pit• Non CMP RelatedDefectivity: Defects from Etch. Defects fromLiner/Seed Deposition.Defect Reduction of Copper BEOLfor Advanced ULSI InterconnectHsueh-Chung Chen, et el., 2001 IEEEpp. 21-23 (UMC)

CMP Related Defectivity – Micro Scratch‣ Effect of pH in the Colloidal Silica-Water systemSuspected U-scratch sourceR.K. Iler, The Chemistry of Silica, John Wiley & Sons Inc.,New York (1979)• Possible actions to prevent the aluminaabrasive particles being embedded into OX layer: Slurry filter Buffing on a soft pad Less down force (Soft-Landing). Pads. Pad conditioning. Speed.Defect Reduction of Copper BEOLfor Advanced ULSI InterconnectHsueh-Chung Chen, et el., 2001 IEEEpp. 21-23 (UMC)

CMP Related Defectivity – Micro Scratch PossibleMechanism:Scratch by high rateItems Cu film Ta film W film Al2O3 abrasive Silica abrasiveMohsHardness2.5~3 6.5 7.5~8 9 6.8~7.0Abrasive used for Cu polish Oxide polishU-scratchCu polish by high rate Cu polish by low rate TaN & Oxide polishScratch by low rateSurfaces will be scratched by large Al2O3:(1) Cu(2) TaN (will be removed after TaN polish)(3) Oxide (will be protected from TaN film)ECP about 7000ACu polish by high rateCu polish by low rateTaN & Oxide polishD-scratchScratch by oxide polishSurfaces will be scratched by large Silica:(1) Cu(2) OxideCu polish by high rateCu polish by low rateTaN & Oxide polish

CMP Related Defectivity – Surface PA & Slurry• Slurry Particle AdhesionInteractions:LEFT Blankfor Confidential• Possible actions forsurface PA & Slurry: Replace new brush Check brush gap Check exhaust Check EC flow

CMP Related Defectivity – Corrosion• Risks: Corrosion/voids in Metal Trench -> increase lineresistance/openCorrosion/by-product re-deposition -> Metal short.• Currently reported sources of corrosion Reaction of the Cu with the slurry Galvanic corrosion Photo-assisted corrosions• Prevention: need inhibitor (BTA, Benzotriazole).• Mechanism:LEFT BlankHNNfor ConfidentialN Corrosion inhibitor: BTA Cu Grain size is dependent mainly on the annealingconditions. Cu film with very Large Grain size may be easier tocorrode along the Grain boundaries.BTA / MSDS1.Appearance: White to light tan, odorless,crystalline compound.2.Chemical composition:C6H4NHN23.Formula weight: 119.13C4.Melting point: 98-99 o C5.Boiling point: 204 o C @15mmHg6.Solubility: Solute in alcohol and benzene;little in H2O.

CMP Related Defectivity – Galvanic Corrosion• Mechanism: The Galvanic potential is different for two Metalsconnected to N+ and P+ regions, respectively. Water on the surface creates a closed loopbetween the two electrodes.LEFT Blank Energy from environments created a built-inpotential in the p-n junction -> provides thedriving force of the Galvanic cell.for Confidential The re-deposition of Cu shorts the Metal lines.•Cu-Ta Galvanic cell effect• galvanic corrosion(occurred on devicewafer and M1)CuTa++CuN+/NWConnect toP+/NW

Corrosion Current (A)10e-9CMP Related Defectivity – BTA Residue• Protective Mode:(Corrosion concern)CUAlBTA conc.(1) Cu BTA Cu-BTA, Cucorrosion, Cu,BTA(2) BTA ,, BTA, BTA residueBTABTA BTALEFT BlankBTABTABTABTABTABTA BTABTA BTABTAfor ConfidentialBTABTABTA BTABTABTABTACuCu160Effect of BTA on Corrosion濃14012010080600.1% BTA in SS12BTA+SS12Current BTA concentrationin fab14: 0.1wt% in SS06,0.02wt% in DI4020BTA +DI water00 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5BTA wt%

CMP Defect – Step by Step CheckLEFT Blankfor Confidential

Q & A

CMP(AMAT tools)• AMAT Reflexion:• Applied Material 300mm CMP polisher tool.• mature technology .• AMAT Reflexion LK:• Applied Material 300mm CMP tool.• multi-zone pressure control Profile control.• Vapor dryer LK film wafer water spot defect.• AMAT Reflexion GT:• Applied Material 300mm CMP tool, high WPH platform.• Polisher head, cleaner, 7-zone pressure control.STI ILD W M1/IM TMC011~13 Reflexion Reflexion Reflexion, LK Reflexion, LKN90~80 Reflexion Reflexion LK Reflexion, LKN65~55 Reflexion Reflexion, LK LK LK, GTN4x LK LK, GT

CMP(Ebara tools)• Ebara 300:• Ebara 300mm CMP polisher tool.• WCMP F14.• Ebara 300S:• Ebara 300mm CMP tool.• Bi-chamber design WCMP.• Ebara 300S2:• Ebara 300mm CMP tool.• Motor torque E/P system IPA dryer Ox, W, and CuCMP.STI ILD W M1/IM TMC011~13 300S, 300S2N90~80 300S, 300S2N65~55 300S, 300S2 300S2N4x 300S2 300S2 300S2 300S2

Slurry NameSS-25E(or SS-12)F3(9201G)Abrasive type Fumed Silica CeO2 Colloidal SilicapH 11 5 2.5Dilution ratio(Slurry vs. DI)Solid contentSelectivity(Ox vs. SiN)• Abrasive:• Slurry:Inhibitor• POU: Point of useOxide SlurryK11:1 1:2 1:225%(POU: 12.5%)2.5%(POU: 0.8%)9%(POU: 3%)1:3 1:30 1:2SlurryAbrasive, Chemical, and Inhibitor.Metal CMP.• PSD: Particle Size Distribution Abrasive particle• LPC: Large particle count Slurry Particle

Slurry Name 5306 F2 F1ContentTechnologyCu: 5306TaN: T605Buff: SS-6UTM layersCu: F2ATaN: F2BBuff: F2CC011/13: M1~TMN90/80: TMCu: F1A (3900)Buff: F1BN90/80: M1/IMN4x~N65: AllTool type Reflexion Reflexion, LK LK, GT, EbaraDishingCu SlurryLargeLarge(similar with 5306)LowU-sc performance Worse Worse Better• Abrasive: Abrasive fumed silica Al 2 O 3micro-scratch (u-sc) defect Abrasive colloidal type silicau-sc defect• Chemical: Slurry Chemical H2O2 Cu• Inhibitor: corrosion Cu slurry BTA