US20120175264A1 - Wafer pretreatment for copper electroplating - Google Patents
Wafer pretreatment for copper electroplating Download PDFInfo
- Publication number
- US20120175264A1 US20120175264A1 US13/496,251 US201013496251A US2012175264A1 US 20120175264 A1 US20120175264 A1 US 20120175264A1 US 201013496251 A US201013496251 A US 201013496251A US 2012175264 A1 US2012175264 A1 US 2012175264A1
- Authority
- US
- United States
- Prior art keywords
- copper
- cupur
- concentration
- solution
- pretreatment solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000009713 electroplating Methods 0.000 title claims abstract description 54
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 43
- 239000010949 copper Substances 0.000 title claims abstract description 43
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 43
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 claims abstract description 68
- 229910001431 copper ion Inorganic materials 0.000 claims abstract description 67
- 238000000034 method Methods 0.000 claims abstract description 39
- 239000000654 additive Substances 0.000 claims description 88
- 230000000996 additive effect Effects 0.000 claims description 84
- 239000004094 surface-active agent Substances 0.000 claims description 14
- AFVFQIVMOAPDHO-UHFFFAOYSA-N Methanesulfonic acid Chemical compound CS(O)(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-N 0.000 claims description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 10
- 239000002253 acid Substances 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 6
- 150000002894 organic compounds Chemical class 0.000 claims description 6
- 230000007547 defect Effects 0.000 claims description 5
- 229940098779 methanesulfonic acid Drugs 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims 1
- 239000000243 solution Substances 0.000 description 82
- 229910000365 copper sulfate Inorganic materials 0.000 description 34
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 34
- 238000007747 plating Methods 0.000 description 32
- 230000000052 comparative effect Effects 0.000 description 23
- BSXVKCJAIJZTAV-UHFFFAOYSA-L copper;methanesulfonate Chemical compound [Cu+2].CS([O-])(=O)=O.CS([O-])(=O)=O BSXVKCJAIJZTAV-UHFFFAOYSA-L 0.000 description 17
- -1 copper fluoroborate Chemical compound 0.000 description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- 239000011593 sulfur Substances 0.000 description 5
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 125000003277 amino group Chemical group 0.000 description 3
- 239000008367 deionised water Substances 0.000 description 3
- 229910021641 deionized water Inorganic materials 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 150000002148 esters Chemical class 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 229910021642 ultra pure water Inorganic materials 0.000 description 3
- 239000012498 ultrapure water Substances 0.000 description 3
- AFEITPOSEVENMK-UHFFFAOYSA-N 1-(2-hydroxyethyl)imidazolidine-2-thione Chemical compound OCCN1CCNC1=S AFEITPOSEVENMK-UHFFFAOYSA-N 0.000 description 2
- OBDVFOBWBHMJDG-UHFFFAOYSA-N 3-mercapto-1-propanesulfonic acid Chemical compound OS(=O)(=O)CCCS OBDVFOBWBHMJDG-UHFFFAOYSA-N 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- JAWMENYCRQKKJY-UHFFFAOYSA-N [3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-ylmethyl)-1-oxa-2,8-diazaspiro[4.5]dec-2-en-8-yl]-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]methanone Chemical compound N1N=NC=2CN(CCC=21)CC1=NOC2(C1)CCN(CC2)C(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F JAWMENYCRQKKJY-UHFFFAOYSA-N 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 229920001451 polypropylene glycol Polymers 0.000 description 2
- KCXFHTAICRTXLI-UHFFFAOYSA-N propane-1-sulfonic acid Chemical compound CCCS(O)(=O)=O KCXFHTAICRTXLI-UHFFFAOYSA-N 0.000 description 2
- 159000000000 sodium salts Chemical class 0.000 description 2
- NJZLKINMWXQCHI-UHFFFAOYSA-N sodium;3-(3-sulfopropyldisulfanyl)propane-1-sulfonic acid Chemical compound [Na].[Na].OS(=O)(=O)CCCSSCCCS(O)(=O)=O NJZLKINMWXQCHI-UHFFFAOYSA-N 0.000 description 2
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 description 2
- WGJCBBASTRWVJL-UHFFFAOYSA-N 1,3-thiazolidine-2-thione Chemical compound SC1=NCCS1 WGJCBBASTRWVJL-UHFFFAOYSA-N 0.000 description 1
- FHTDDANQIMVWKZ-UHFFFAOYSA-N 1h-pyridine-4-thione Chemical compound SC1=CC=NC=C1 FHTDDANQIMVWKZ-UHFFFAOYSA-N 0.000 description 1
- IIEJGTQVBJHMDL-UHFFFAOYSA-N 2-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]-5-[2-oxo-2-[3-(sulfamoylamino)pyrrolidin-1-yl]ethyl]-1,3,4-oxadiazole Chemical compound C1CN(CC1NS(=O)(=O)N)C(=O)CC2=NN=C(O2)C3=CN=C(N=C3)NC4CC5=CC=CC=C5C4 IIEJGTQVBJHMDL-UHFFFAOYSA-N 0.000 description 1
- RILZRCJGXSFXNE-UHFFFAOYSA-N 2-[4-(trifluoromethoxy)phenyl]ethanol Chemical compound OCCC1=CC=C(OC(F)(F)F)C=C1 RILZRCJGXSFXNE-UHFFFAOYSA-N 0.000 description 1
- AETVBWZVKDOWHH-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]-3-(1-ethylazetidin-3-yl)oxypyrazol-1-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C=1C(=NN(C=1)CC(=O)N1CC2=C(CC1)NN=N2)OC1CN(C1)CC AETVBWZVKDOWHH-UHFFFAOYSA-N 0.000 description 1
- KNDAEDDIIQYRHY-UHFFFAOYSA-N 2-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]-3-(piperazin-1-ylmethyl)pyrazol-1-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C=1C(=NN(C=1)CC(=O)N1CC2=C(CC1)NN=N2)CN1CCNCC1 KNDAEDDIIQYRHY-UHFFFAOYSA-N 0.000 description 1
- FULCXPQDMXUVSB-UHFFFAOYSA-N 3-(3-sulfanylpropylsulfonyloxy)propane-1-sulfonic acid Chemical compound OS(=O)(=O)CCCOS(=O)(=O)CCCS FULCXPQDMXUVSB-UHFFFAOYSA-N 0.000 description 1
- BMYNFMYTOJXKLE-UHFFFAOYSA-N 3-azaniumyl-2-hydroxypropanoate Chemical compound NCC(O)C(O)=O BMYNFMYTOJXKLE-UHFFFAOYSA-N 0.000 description 1
- REEBJQTUIJTGAL-UHFFFAOYSA-N 3-pyridin-1-ium-1-ylpropane-1-sulfonate Chemical compound [O-]S(=O)(=O)CCC[N+]1=CC=CC=C1 REEBJQTUIJTGAL-UHFFFAOYSA-N 0.000 description 1
- LLQHSBBZNDXTIV-UHFFFAOYSA-N 6-[5-[[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperazin-1-yl]methyl]-4,5-dihydro-1,2-oxazol-3-yl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)N1CCN(CC1)CC1CC(=NO1)C1=CC2=C(NC(O2)=O)C=C1 LLQHSBBZNDXTIV-UHFFFAOYSA-N 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- BWGNESOTFCXPMA-UHFFFAOYSA-N Dihydrogen disulfide Chemical compound SS BWGNESOTFCXPMA-UHFFFAOYSA-N 0.000 description 1
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- PDQAZBWRQCGBEV-UHFFFAOYSA-N Ethylenethiourea Chemical compound S=C1NCCN1 PDQAZBWRQCGBEV-UHFFFAOYSA-N 0.000 description 1
- 102000004310 Ion Channels Human genes 0.000 description 1
- VCUFZILGIRCDQQ-KRWDZBQOSA-N N-[[(5S)-2-oxo-3-(2-oxo-3H-1,3-benzoxazol-6-yl)-1,3-oxazolidin-5-yl]methyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C1O[C@H](CN1C1=CC2=C(NC(O2)=O)C=C1)CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F VCUFZILGIRCDQQ-KRWDZBQOSA-N 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- FHKPLLOSJHHKNU-INIZCTEOSA-N [(3S)-3-[8-(1-ethyl-5-methylpyrazol-4-yl)-9-methylpurin-6-yl]oxypyrrolidin-1-yl]-(oxan-4-yl)methanone Chemical compound C(C)N1N=CC(=C1C)C=1N(C2=NC=NC(=C2N=1)O[C@@H]1CN(CC1)C(=O)C1CCOCC1)C FHKPLLOSJHHKNU-INIZCTEOSA-N 0.000 description 1
- RAOSIAYCXKBGFE-UHFFFAOYSA-K [Cu+3].[O-]P([O-])([O-])=O Chemical compound [Cu+3].[O-]P([O-])([O-])=O RAOSIAYCXKBGFE-UHFFFAOYSA-K 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 150000001879 copper Chemical class 0.000 description 1
- DOBRDRYODQBAMW-UHFFFAOYSA-N copper(i) cyanide Chemical compound [Cu+].N#[C-] DOBRDRYODQBAMW-UHFFFAOYSA-N 0.000 description 1
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- CCIVGXIOQKPBKL-UHFFFAOYSA-M ethanesulfonate Chemical compound CCS([O-])(=O)=O CCIVGXIOQKPBKL-UHFFFAOYSA-M 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 150000002605 large molecules Chemical class 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid group Chemical group C(CCCCCCC\C=C/CCCCCCCC)(=O)O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920001521 polyalkylene glycol ether Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920000151 polyglycol Polymers 0.000 description 1
- 239000010695 polyglycol Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 238000005549 size reduction Methods 0.000 description 1
- 125000004079 stearyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D7/00—Electroplating characterised by the article coated
- C25D7/12—Semiconductors
- C25D7/123—Semiconductors first coated with a seed layer or a conductive layer
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
- H01L21/283—Deposition of conductive or insulating materials for electrodes conducting electric current
- H01L21/288—Deposition of conductive or insulating materials for electrodes conducting electric current from a liquid, e.g. electrolytic deposition
- H01L21/2885—Deposition of conductive or insulating materials for electrodes conducting electric current from a liquid, e.g. electrolytic deposition using an external electrical current, i.e. electro-deposition
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
- H01L21/76898—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics formed through a semiconductor substrate
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/38—Electroplating: Baths therefor from solutions of copper
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
- H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
- H01L21/76877—Filling of holes, grooves or trenches, e.g. vias, with conductive material
Definitions
- the present invention relates to a pretreatment process for copper electroplating of via and trench features on a semiconductor wafer.
- the process of the invention is particularly suited for plating deep vias (including through silicon vias (TSV)) or trenches, or those with high aspect ratios.
- TSV through silicon vias
- Copper electroplating is one of the key processes for fabricating semiconductor interconnections. During copper electroplating, it is sometimes difficult to achieve ideal fill results for vias, trenches and other connecting structures on a wafer.
- the pretreatment process is of critical importance in achieving desired fill yield.
- the objective of pretreatment is preventing air bubbles from remaining at the bottom of vias.
- U.S. Pat. No. 6,562,222 teaches that acidic copper sulfate electrolytes can easily dissolve the copper seed layers due to the sulfuric acid contained in the electroplating solution.
- current industrial pretreatment practice is to soak the wafer in a surfactant solution or in deionized water prior to copper plating.
- JP2008001963 discloses a pretreatment solution containing ammonium and surfactants.
- U.S. Pat. No. 6,491,806 uses deionized water in the wafer pretreatment, eliminating bubbles from the fill water in the vias.
- US 2007/235343 A1 discloses the pretreatment with a solution comprising a sulfur containing organic compound.
- a solution comprising a sulfur containing organic compound.
- copper ions may be present in the pretreatment solution in a range of 0.01 to about 5.0 g/l.
- the present invention provides a pretreatment process for copper electroplating of via and trench features on a wafer to reduce voids and defects, including filling the via or trench feature with a pretreatment solution, wherein the pretreatment solution comprises copper ions from 10 g/L to 300 g/L.
- the present invention also provides a process for copper plating, a copper electroplating pretreatment solution comprising copper ions and the use of solutions comprising copper ions from 10 g/L to 300 g/L for pretreatment before copper electroplating.
- the present invention can reduce the time required for electroplating. Less over-plating and enhanced uniformity can also be achieved. Common step-up current densities for plating are unnecessary and a higher current density can be used from the onset of the plating process. Additionally, a larger range in the quantity of additives in the electroplating solution can be controlled during the electroplating process without causing undesired results.
- the copper electroplating pretreatment solution used in the process of the present invention contains 10 g/L to 300 g/L of copper ions, preferably, 10 g/L to 136 g/L of copper ions, more preferably, 20 g/L to 200 g/L, even more preferably, 30 g/L to 136 g/L. And preferably, the pretreatment solution has a higher copper concentration than the electrolyte used in a copper electroplating process.
- the electrolyte currently used in a copper electroplating process typically contains copper ions from 30 g/L to 100 g/L.
- Copper ions can be obtained by any source commonly used in the semiconductor field, including but not limited to copper sulfate, copper alkanesulfonate, copper phosphate, copper fluoroborate, and copper cyanide or similar copper salts.
- copper ions may be provided by copper sulfate or copper methanesulfonate.
- Additives such as accelerators (brighteners), suppressors, and levelers are typically included in a copper electroplating solution to improve electroplating behavior by improving surface deposition and thickness uniformity and enhancing chemical reactions and filling of high aspect ratio features.
- Such additives can also be optionally added to the pretreatment solution used in the process of the present invention.
- Accelerators are used for accelerating size reduction of deposited particles.
- the accelerator typically is sulfur-containing organic compounds and relatively increases rate of copper deposition in a pattern on which a trench with a narrow width is formed. Examples of suitable accelerators are set forth in U.S. Pat. No.
- 6,679,983 including n,n-dimethyl-dithiocarbamic acid-(3-sulfopropyl)ester; 3-mercapto-propylsulfonic acid-(3-sulfopropyl)ester; 3-mercaptopropylsulfonic acid (sodium salt); carbonic acid-dithio-o-ethylester-s-ester with 3-mercapto-l-propane sulfonic acid (potassium salt); bissulfopropyl disulfide; 3-(benzthiazolyl-s-thio)propyl sulfonic acid (sodium salt); pyridinium propyl sulfobetaine; 1-sodium-3-mercaptopropane-1-sulfonate; disodium bis-(3-sulfopropyl)disulfide; or mixtures thereof.
- the accelerator comprises disodium bis-(3-sulfopropyl)disulfide.
- concentration of the accelerator in the pretreatment solution of the present invention is preferably from 0 mL/L to about 50 mL/L, more preferably from 0 mL/L to 35 mL/L.
- concentration of the active compound of the accelerator in the pretreatment solution of the present invention is preferably from 0 ppm to 400 ppm.
- Suppressors are used for increasing an over voltage for depositing a plating copper at more uniform electrodeposition.
- Suppressors for copper electroplating are generally oxygen-containing high molecular weight compounds.
- Suitable suppressors include, but are not limited to, carboxymethylcellulose, nonylphenolpolyglycol ether, octandiolbis-(polyalkylene glycolether), octanolpolyalkylene glycolether, oleic acidpolyglycol ester, polyethylenepropylene glycol, polyethylene glycol, polyethylene glycoldimethylether, polyoxypropylene glycol, polypropylene glycol, polyvinylalcohol, stearic acidpolyglycol ester, polyethylene oxide, stearyl alcoholpolyglycol ether, and the like.
- the suppressor comprises poly(ethylene oxide-propylene oxide).
- concentration of the suppressor in the pretreatment solution of the present invention is preferably from 0 mL/L to about 40 mL/L, more preferably from 0 mL/L to about 30 mL/L.
- concentration of the active compound of the suppressor in the pretreatment solution of the present invention is preferably from 0 ppm to 600 ppm.
- the pretreatment solution is essentially free of any accelerator, i.e. any sulfur-containing organic compound.
- “Essentially free of any sulfur containing organic compound” means that the solution comprises less than 0.1 mg/L, preferably less than 0.01 mg/L, most preferably less than 0.001 mg/l of a sulfur containing organic compound.
- Levelers are used for reducing surface roughness. They are similar to suppressors in that they reduce deposition rate.
- Levelers for copper electroplating generally comprise nitrogen-containing organic compounds. Compounds with an amino group or substituted amino groups are commonly used. Such compounds are disclosed in U.S. Pat. No. 4,376,685, U.S. Pat. No. 4,555,315, and U.S. Pat. No. 3,770,598. Examples include 1-(2-hydroxyethyl)-2-imidazolidinethione; 4-mercaptopyridine; 2-mercaptothiazoline; ethylene thiourea; thiourea; alkylated polyalkyleneimine.
- the leveler is 1-(2-hydroxyethyl)-2-imidazolidinethione.
- the concentration of the leveler in the pretreatment solution of the present invention is preferably from 0 mL/L to about 50 mL/L, more preferably from 0 to about 40 mL/L.
- the concentration of the active compound of the leveler in the pretreatment solution of the present invention is from 0 ppm to 500 ppm.
- the pretreatment solution of the present invention may also comprise a surfactant.
- the surfactant is used to lower the surface tension of the solution.
- Useful surfactants include high molecular weight polymers, modified polyacrylic polymer, modified polysiloxane, preferably polyglycol type polymers and co-polymers.
- the concentration of surfactant in the pretreatment solution may range from 0 wt% to 3 wt %.
- the pretreatment solution of the present invention may also comprise an acid.
- the acid can be selected from the group consisting of sulfuric acid, alkanesulfonic acids (such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid and trifluoro-methanesulfonmic acid), sulfamic acid; hydrochloric acid; hydrobromic acid; and fluoroboric acid and mixture thereof.
- the acid is sulfuric acid, methanesulfonic acids or hydrochloric acid.
- the concentration of the acid is from 0 mL/L to about 40 mL/L.
- the via or trench feature being plated has an aspect ratio greater than 2:1, preferably 3:1 to 40:1.
- the via or trench feature has a depth of more than 10 micrometers, preferably 10 micrometers to 300 micrometers.
- the process of the subject invention can further comprise a water rinse step or spin dry step to remove the pretreatment solution from the surface of the wafer.
- the examples show the pretreatment solutions, electroplating solutions, and via patterns.
- the test wafer was pretreated with the pretreatment solution and then immersed in deionized water (DI water) for about 2 seconds.
- DI water deionized water
- the “pretreated” here means, for example, contacted, wetted or rinsed.
- the step of immersing in DI water was omitted because the pretreatment solutions in both cases were ultra pure water.
- the wafer was then immersed in the electroplating solution for plating.
- the anode was a copper anode. Except for Examples 15 and 16 and Comparative Examples 5 and 6, the power supply supplied an average current density of 0.3 ASD (Ampere per square decimeter). Plating was continued for about 40 minutes.
- Example 15 and Comparative Example 5 the power supply supplied an average current density of 0.1 ASD. Plating was continued for about 30 minutes.
- Example 16 and Comparative Examples 6 the power supply supplied an average current density of 0.8 ASD. Plating was continued for about 30 minutes.
- Pretreatment solution ultra pure water.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result showed voids in the bottom.
- Pretreatment solution copper sulfate with copper ion concentration 10 g/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper sulfate with copper ion concentration 40 g/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment Solution copper sulfate with copper ion concentration 80 g/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper methanesulfonate with copper ion concentration 90 g/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment Solution copper methanesulfonate with copper ion concentration 120 g/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper methanesulfonate with copper ion concentration 136 g/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution CuPurTM T5000 (0.3% surfactant; available from BASF).
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers.
- the plating result showed voids in the bottom.
- Pretreatment solution ultra pure water.
- Electroplating solution CuPurTM T 1010 (copper methanesulfonate, copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result showed voids in the bottom.
- Pretreatment Solution CuPurTM T5000 (0.3% surfactant; available from BASF).
- Electroplating solution CuPurTM T 1010 (copper methanesulfonate, copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers.
- the plating result showed voids in the bottom.
- Pretreatment solution copper sulfate with copper ion concentration 40 g/L, sulfuric acid 10 g/L, and chloride ion 50 ppm.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper sulfate with copper ion concentration 40 g/L, CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper methanesulfonate with copper ion concentration 90 g/L, methanesulfonic acid 5 mL/L.
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper methanesulfonate with copper ion concentration 90 g/L, CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 2 mL/L (as a suppressor available from BASF).
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper methanesulfonate with copper ion concentration 90 g/L, CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 2 mL/L (as a suppressor available from BASF), and surfactant (0.2 w%).
- Electroplating solution copper methanesulfonate (copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment solution copper methanesulfonate with copper ion concentration 120 g/L, CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 2 mL/L (as a suppressor available from BASF), and surfactant (0.2 w%).
- Electroplating solution CuPurTM T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 5 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment Solution copper methanesulfonate with copper ion concentration 120 g/L, CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 2 mL/L (as a suppressor available from BASF), and surfactant (0.2 w%).
- Electroplating solution copper methanesulfonate (copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 4:1 (depth:opening diameter), resulting from an opening having a diameter of 30 micrometers and a depth of 150 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment Solution copper methanesulfonate with copper ion concentration 180 g/L, CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 2 mL/L (as an suppressor available from BASF), CuPurTM T 4000 additive 2 mL/L (as a leveler available from BASF), and surfactant (0.2 w %).
- Electroplating solution copper methanesulfonate (copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers.
- the plating result was void-free and seam-free.
- Pretreatment Solution copper sulfate with copper ion concentration 0.67 g/L (10.6 mmol/L), CuPurTM T 2000 additive 1.06 g/L (3 mmol/L) (as an accelerator available from BASF).
- Electroplating solution copper methanesulfonate (copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 6:1 (depth:opening diameter), resulting from an opening having a diameter of 10 micrometers and a depth of 60 micrometers.
- the cross section of the features showed bottom voids.
- Pretreatment Solution copper sulfate with copper ion concentration 60 g/L.
- Electroplating solution copper methanesulfonate (copper ion concentration 90 g/L), CuPurTM T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 16 mL/L (as a leveler available from BASF).
- the vias had an aspect ratio of 6:1 (depth:opening diameter), resulting from an opening having a diameter of 10 micrometers and a depth of 60 micrometers.
- the cross section of the features was void-free and seam free.
- Pretreatment Solution copper sulfate with copper ion concentration 0.67 g/L (10.6 mmol/L), CuPurTM T 2000 additive 1.06 g/L (3 mmol/L) (as an accelerator available from BASF).
- Electroplating solution copper sulfate (copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 10 mL/L (as a leveler available from BASF).
- a 10 micrometer trench had an aspect ratio of 11:2 (depth:width), resulting from a width of 10 micrometers and a depth of 55 micrometers.
- a 20 micrometer trench had an aspect ratio of 13:2 (depth:width), resulting from a width of 20 micrometers and a depth of 65 micrometers.
- the cross section of the features showed bottom defects.
- Pretreatment Solution copper sulfate with copper ion concentration 60 g/L.
- Electroplating solution copper sulfate (copper ion concentration 40 g/L), CuPurTM T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPurTM T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPurTM T 4000 additive 10 mL/L (as a leveler available from BASF).
- the 10 micrometer trench had an aspect ratio of 11:2 (depth:width), resulting from a width having 10 micrometers and a depth of 55 micrometers.
- the 20 micrometer trench had an aspect ratio of 13:2 (depth: width), resulting from a width having 20 micrometers and a depth of 65 micrometers.
- the cross section of the features was defect-free and seam-free.
- Table 2 shows the filling results for different concentrations of copper ions in the pretreatment solution.
- the results clearly show that a pretreatment solution of the present invention comprising any of the tested concentrations of copper ions will eliminate occurrence of voids or seams.
- Comparative Examples 5 and 6 the same concentrations of copper ions and accelerator as used in Example 1 of US 2007/235343 were used. The experiments were repeated in examples 15 and 16, respectively, however, without accelerator and higher copper concentrations.
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Abstract
The present invention is directed to a pretreatment process for copper electroplating of via or trench features on a wafer, comprising filling the via or trench feature with a pretreatment solution, wherein the pretreatment solution comprises copper ions.
Description
- The present invention relates to a pretreatment process for copper electroplating of via and trench features on a semiconductor wafer. The process of the invention is particularly suited for plating deep vias (including through silicon vias (TSV)) or trenches, or those with high aspect ratios.
- Copper electroplating is one of the key processes for fabricating semiconductor interconnections. During copper electroplating, it is sometimes difficult to achieve ideal fill results for vias, trenches and other connecting structures on a wafer.
- In addition to the processes of chemical formulation and bath composition, the pretreatment process is of critical importance in achieving desired fill yield. The objective of pretreatment is preventing air bubbles from remaining at the bottom of vias.
- It is well understood that it is difficult to remove air from the bottom of a via using an electrolyte solution. U.S. Pat. No. 6,562,222 teaches that acidic copper sulfate electrolytes can easily dissolve the copper seed layers due to the sulfuric acid contained in the electroplating solution. Thus, current industrial pretreatment practice is to soak the wafer in a surfactant solution or in deionized water prior to copper plating. For example, JP2008001963 discloses a pretreatment solution containing ammonium and surfactants. U.S. Pat. No. 6,491,806 uses deionized water in the wafer pretreatment, eliminating bubbles from the fill water in the vias. During electroplating, copper ions must diffuse from the top of the via or trench to plate the bottom of the via or trench. However, some copper will deposit on the top side wall of the via or trench, due to a higher copper ion concentration near the side walls than at the bottom. This leads to pinching off, causing formation of voids or seams. Additives such as accelerators, suppressors and levelers can inhibit the rate of top and top side wall deposit to achieve void free results. However, with vias of higher aspect ratios, the side wall constricts the copper ion channel, reducing diffusion of copper ions, and increasing the difficulty of preventing voids or seams in the via or trench. Hence, a more robust solution is required.
- US 2007/235343 A1 discloses the pretreatment with a solution comprising a sulfur containing organic compound. Optionally also copper ions may be present in the pretreatment solution in a range of 0.01 to about 5.0 g/l.
- In view of the problems described, the present invention provides a pretreatment process for copper electroplating of via and trench features on a wafer to reduce voids and defects, including filling the via or trench feature with a pretreatment solution, wherein the pretreatment solution comprises copper ions from 10 g/L to 300 g/L.
- The present invention also provides a process for copper plating, a copper electroplating pretreatment solution comprising copper ions and the use of solutions comprising copper ions from 10 g/L to 300 g/L for pretreatment before copper electroplating.
- Due to the above-mentioned concerns and teachings in the prior art, copper electrolytes and copper ions had not previously been considered for use in pretreatment processes for plating vias or trenches. Surprisingly, however, it is found that using a pretreatment solution comprising copper ions in sufficient concentration can effectively eliminate the occurrence of voids or seams when plating copper in vias or trenches of a wafer. After the pretreatment step, the vias and trenches are full of the pretreatment solution. During electroplating, the copper ions left at the bottom of a via compensate for limited diffusion of copper ions from the electroplating solution to the bottom of the via, and are immediately available as a copper source for plating on the surface of the bottom of the via. Thus, an ideal and desired fill result can be more easily achieved, especially for vias or trenches of greater aspect ratio or depth.
- Because of the copper ions left in vias or trenches, the present invention can reduce the time required for electroplating. Less over-plating and enhanced uniformity can also be achieved. Common step-up current densities for plating are unnecessary and a higher current density can be used from the onset of the plating process. Additionally, a larger range in the quantity of additives in the electroplating solution can be controlled during the electroplating process without causing undesired results.
- The copper electroplating pretreatment solution used in the process of the present invention contains 10 g/L to 300 g/L of copper ions, preferably, 10 g/L to 136 g/L of copper ions, more preferably, 20 g/L to 200 g/L, even more preferably, 30 g/L to 136 g/L. And preferably, the pretreatment solution has a higher copper concentration than the electrolyte used in a copper electroplating process. The electrolyte currently used in a copper electroplating process typically contains copper ions from 30 g/L to 100 g/L.
- Copper ions can be obtained by any source commonly used in the semiconductor field, including but not limited to copper sulfate, copper alkanesulfonate, copper phosphate, copper fluoroborate, and copper cyanide or similar copper salts. Preferably, copper ions may be provided by copper sulfate or copper methanesulfonate.
- Additives such as accelerators (brighteners), suppressors, and levelers are typically included in a copper electroplating solution to improve electroplating behavior by improving surface deposition and thickness uniformity and enhancing chemical reactions and filling of high aspect ratio features.
- Such additives can also be optionally added to the pretreatment solution used in the process of the present invention.
- Accelerators (or brighteners) are used for accelerating size reduction of deposited particles. The accelerator typically is sulfur-containing organic compounds and relatively increases rate of copper deposition in a pattern on which a trench with a narrow width is formed. Examples of suitable accelerators are set forth in U.S. Pat. No. 6,679,983 including n,n-dimethyl-dithiocarbamic acid-(3-sulfopropyl)ester; 3-mercapto-propylsulfonic acid-(3-sulfopropyl)ester; 3-mercaptopropylsulfonic acid (sodium salt); carbonic acid-dithio-o-ethylester-s-ester with 3-mercapto-l-propane sulfonic acid (potassium salt); bissulfopropyl disulfide; 3-(benzthiazolyl-s-thio)propyl sulfonic acid (sodium salt); pyridinium propyl sulfobetaine; 1-sodium-3-mercaptopropane-1-sulfonate; disodium bis-(3-sulfopropyl)disulfide; or mixtures thereof. Preferably, the accelerator comprises disodium bis-(3-sulfopropyl)disulfide. The concentration of the accelerator in the pretreatment solution of the present invention is preferably from 0 mL/L to about 50 mL/L, more preferably from 0 mL/L to 35 mL/L. The concentration of the active compound of the accelerator in the pretreatment solution of the present invention is preferably from 0 ppm to 400 ppm.
- Suppressors are used for increasing an over voltage for depositing a plating copper at more uniform electrodeposition. Suppressors for copper electroplating are generally oxygen-containing high molecular weight compounds. Suitable suppressors include, but are not limited to, carboxymethylcellulose, nonylphenolpolyglycol ether, octandiolbis-(polyalkylene glycolether), octanolpolyalkylene glycolether, oleic acidpolyglycol ester, polyethylenepropylene glycol, polyethylene glycol, polyethylene glycoldimethylether, polyoxypropylene glycol, polypropylene glycol, polyvinylalcohol, stearic acidpolyglycol ester, polyethylene oxide, stearyl alcoholpolyglycol ether, and the like. Preferably, the suppressor comprises poly(ethylene oxide-propylene oxide). The concentration of the suppressor in the pretreatment solution of the present invention is preferably from 0 mL/L to about 40 mL/L, more preferably from 0 mL/L to about 30 mL/L. The concentration of the active compound of the suppressor in the pretreatment solution of the present invention is preferably from 0 ppm to 600 ppm.
- Preferably, the pretreatment solution is essentially free of any accelerator, i.e. any sulfur-containing organic compound. “Essentially free of any sulfur containing organic compound” means that the solution comprises less than 0.1 mg/L, preferably less than 0.01 mg/L, most preferably less than 0.001 mg/l of a sulfur containing organic compound.
- Levelers are used for reducing surface roughness. They are similar to suppressors in that they reduce deposition rate. Levelers for copper electroplating generally comprise nitrogen-containing organic compounds. Compounds with an amino group or substituted amino groups are commonly used. Such compounds are disclosed in U.S. Pat. No. 4,376,685, U.S. Pat. No. 4,555,315, and U.S. Pat. No. 3,770,598. Examples include 1-(2-hydroxyethyl)-2-imidazolidinethione; 4-mercaptopyridine; 2-mercaptothiazoline; ethylene thiourea; thiourea; alkylated polyalkyleneimine. Preferably, the leveler is 1-(2-hydroxyethyl)-2-imidazolidinethione. The concentration of the leveler in the pretreatment solution of the present invention is preferably from 0 mL/L to about 50 mL/L, more preferably from 0 to about 40 mL/L. The concentration of the active compound of the leveler in the pretreatment solution of the present invention is from 0 ppm to 500 ppm.
- The pretreatment solution of the present invention may also comprise a surfactant. The surfactant is used to lower the surface tension of the solution. Useful surfactants include high molecular weight polymers, modified polyacrylic polymer, modified polysiloxane, preferably polyglycol type polymers and co-polymers. The concentration of surfactant in the pretreatment solution may range from 0 wt% to 3 wt %.
- The pretreatment solution of the present invention may also comprise an acid. The acid can be selected from the group consisting of sulfuric acid, alkanesulfonic acids (such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid and trifluoro-methanesulfonmic acid), sulfamic acid; hydrochloric acid; hydrobromic acid; and fluoroboric acid and mixture thereof. Preferably, the acid is sulfuric acid, methanesulfonic acids or hydrochloric acid. The concentration of the acid is from 0 mL/L to about 40 mL/L.
- According to one aspect of the present invention, the via or trench feature being plated has an aspect ratio greater than 2:1, preferably 3:1 to 40:1. According to another aspect, the via or trench feature has a depth of more than 10 micrometers, preferably 10 micrometers to 300 micrometers.
- According to a further aspect of the present invention, the process of the subject invention can further comprise a water rinse step or spin dry step to remove the pretreatment solution from the surface of the wafer.
- Examples of the present invention and comparative examples will be described. These examples illustrate only preferable embodiments of the present invention, and the present invention is not limited to these examples.
- The examples show the pretreatment solutions, electroplating solutions, and via patterns. In each example, the test wafer was pretreated with the pretreatment solution and then immersed in deionized water (DI water) for about 2 seconds. The “pretreated” here means, for example, contacted, wetted or rinsed. For comparative examples 1 and 3, the step of immersing in DI water was omitted because the pretreatment solutions in both cases were ultra pure water. The wafer was then immersed in the electroplating solution for plating. The anode was a copper anode. Except for Examples 15 and 16 and Comparative Examples 5 and 6, the power supply supplied an average current density of 0.3 ASD (Ampere per square decimeter). Plating was continued for about 40 minutes. For Example 15 and Comparative Example 5 the power supply supplied an average current density of 0.1 ASD. Plating was continued for about 30 minutes. For Example 16 and Comparative Examples 6 the power supply supplied an average current density of 0.8 ASD. Plating was continued for about 30 minutes.
- Pretreatment solution: ultra pure water.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result showed voids in the bottom.
- Pretreatment solution: copper sulfate with copper ion concentration 10 g/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper sulfate with copper ion concentration 40 g/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment Solution: copper sulfate with copper ion concentration 80 g/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper methanesulfonate with copper ion concentration 90 g/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment Solution: copper methanesulfonate with copper ion concentration 120 g/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper methanesulfonate with copper ion concentration 136 g/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: CuPur™ T5000 (0.3% surfactant; available from BASF).
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers. The plating result showed voids in the bottom.
- Pretreatment solution: ultra pure water.
- Electroplating solution: CuPur™ T 1010 (copper methanesulfonate, copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result showed voids in the bottom.
- Pretreatment Solution: CuPur™ T5000 (0.3% surfactant; available from BASF).
- Electroplating solution: CuPur™ T 1010 (copper methanesulfonate, copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers. The plating result showed voids in the bottom.
- Pretreatment solution: copper sulfate with copper ion concentration 40 g/L, sulfuric acid 10 g/L, and chloride ion 50 ppm.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper sulfate with copper ion concentration 40 g/L, CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper methanesulfonate with copper ion concentration 90 g/L, methanesulfonic acid 5 mL/L.
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper methanesulfonate with copper ion concentration 90 g/L, CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 2 mL/L (as a suppressor available from BASF).
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 8:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 50 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper methanesulfonate with copper ion concentration 90 g/L, CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 2 mL/L (as a suppressor available from BASF), and surfactant (0.2 w%).
- Electroplating solution: copper methanesulfonate (copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers. The plating result was void-free and seam-free.
- Pretreatment solution: copper methanesulfonate with copper ion concentration 120 g/L, CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 2 mL/L (as a suppressor available from BASF), and surfactant (0.2 w%).
- Electroplating solution: CuPur™ T 1000 (copper sulfate, copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 5 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers. The plating result was void-free and seam-free.
- Pretreatment Solution: copper methanesulfonate with copper ion concentration 120 g/L, CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 2 mL/L (as a suppressor available from BASF), and surfactant (0.2 w%).
- Electroplating solution: copper methanesulfonate (copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 4:1 (depth:opening diameter), resulting from an opening having a diameter of 30 micrometers and a depth of 150 micrometers. The plating result was void-free and seam-free.
- Pretreatment Solution: copper methanesulfonate with copper ion concentration 180 g/L, CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 2 mL/L (as an suppressor available from BASF), CuPur™ T 4000 additive 2 mL/L (as a leveler available from BASF), and surfactant (0.2 w %).
- Electroplating solution: copper methanesulfonate (copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 10:1 (depth:opening diameter), resulting from an opening having a diameter of 6 micrometers and a depth of 60 micrometers. The plating result was void-free and seam-free.
- Pretreatment Solution: copper sulfate with copper ion concentration 0.67 g/L (10.6 mmol/L), CuPur™ T 2000 additive 1.06 g/L (3 mmol/L) (as an accelerator available from BASF).
- Electroplating solution: copper methanesulfonate (copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 6:1 (depth:opening diameter), resulting from an opening having a diameter of 10 micrometers and a depth of 60 micrometers. The cross section of the features showed bottom voids.
- Pretreatment Solution: copper sulfate with copper ion concentration 60 g/L.
- Electroplating solution: copper methanesulfonate (copper ion concentration 90 g/L), CuPur™ T 2000 additive 12 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 6 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 16 mL/L (as a leveler available from BASF).
- The vias had an aspect ratio of 6:1 (depth:opening diameter), resulting from an opening having a diameter of 10 micrometers and a depth of 60 micrometers. The cross section of the features was void-free and seam free.
- Pretreatment Solution: copper sulfate with copper ion concentration 0.67 g/L (10.6 mmol/L), CuPur™ T 2000 additive 1.06 g/L (3 mmol/L) (as an accelerator available from BASF).
- Electroplating solution: copper sulfate (copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 10 mL/L (as a leveler available from BASF).
- Two trenches were tested. A 10 micrometer trench had an aspect ratio of 11:2 (depth:width), resulting from a width of 10 micrometers and a depth of 55 micrometers. A 20 micrometer trench had an aspect ratio of 13:2 (depth:width), resulting from a width of 20 micrometers and a depth of 65 micrometers. The cross section of the features showed bottom defects.
- Pretreatment Solution: copper sulfate with copper ion concentration 60 g/L.
- Electroplating solution: copper sulfate (copper ion concentration 40 g/L), CuPur™ T 2000 additive 15 mL/L (as an accelerator available from BASF), CuPur™ T 3000 additive 5 mL/L (as a suppressor available from BASF), CuPur™ T 4000 additive 10 mL/L (as a leveler available from BASF).
- Two trenches were tested. The 10 micrometer trench had an aspect ratio of 11:2 (depth:width), resulting from a width having 10 micrometers and a depth of 55 micrometers. The 20 micrometer trench had an aspect ratio of 13:2 (depth: width), resulting from a width having 20 micrometers and a depth of 65 micrometers. The cross section of the features was defect-free and seam-free.
- The final filling features of the examples and comparative examples were checked by cleavage cross-sectional optical microscope or scanning electron microscope (SEM) and in some case by using focused ion beam (FIB) for double confirmation of the observation, and the results are shown in TABLE 1. The results show that the present invention has an excellent effect in eliminating occurrence of voids and seams in the filling result.
-
TABLE 1 No. Aspect ratio Filling result Comparative Example 1 8:1 Voids occurred Comparative Example 2 10:1 Voids occurred Comparative Example 3 8:1 Voids occurred Comparative Example 4 10:1 Voids occurred Example 1 8:1 Void-free and seam-free Example 2 8:1 Void-free and seam-free Example 3 8:1 Void-free and seam-free Example 4 8:1 Void-free and seam-free Example 5 8:1 Void-free and seam-free Example 6 8:1 Void-free and seam-free Example 7 8:1 Void-free and seam-free Example 8 8:1 Void-free and seam-free Example 9 8:1 Void-free and seam-free Example 10 8:1 Void-free and seam-free Example 11 10:1 Void-free and seam-free Example 12 10:1 Void-free and seam-free Example 13 4:1 Void-free and seam-free Example 14 10:1 Void-free and seam-free Comparative Example 5 6:1 Voids occurred Comparative Example 6 13:2 Defects occurred Example 15 6:1 Void-free and seam-free Example 16 13:2 Defect-free and seam-free - Holding other parameters constant, Table 2 shows the filling results for different concentrations of copper ions in the pretreatment solution. The results clearly show that a pretreatment solution of the present invention comprising any of the tested concentrations of copper ions will eliminate occurrence of voids or seams. In Comparative Examples 5 and 6 the same concentrations of copper ions and accelerator as used in Example 1 of US 2007/235343 were used. The experiments were repeated in examples 15 and 16, respectively, however, without accelerator and higher copper concentrations.
-
TABLE 2 [Cu2+] No. g/L Copper source Filling Result Comparative 1 0 — Voids occurred Comparative 5 0.67 Copper sulfate Voids occurred Comparative 6 0.67 Copper sulfate Defects occurred Example 1 10 Copper sulfate Void-free and seam-free Example 2 40 Copper sulfate Void-free and seam-free Example 3 80 Copper sulfate Void-free and seam-free Example 4 90 Copper Void-free and seam-free methanesulfonate Example 5 120 Copper Void-free and seam-free methanesulfonate Example 6 136 Copper Void-free and seam-free methanesulfonate Example 15 90 Copper sulfate Void-free and seam-free Example 16 40 Copper sulfate Defect-free and seam-free - The invention is not limited by the embodiments described above, which are presented as examples only, and can be modified in various ways within the scope of protection defined by the appended patent claims.
Claims (22)
1. A process for pretreating a via or trench feature on a wafer, the process comprising:
filling a via or trench feature on a wafer with a pretreatment solution comprising copper ions,
wherein a concentration of copper in the pretreatment solution is in a range from 10 g/L to 300 g/L, and the copper concentration of the pretreatment solution is higher than a copper concentration of a copper electroplating solution.
2. (canceled)
3. The process of claim 1 , wherein the pretreatment solution is essentially free of any sulfur-comprising organic compound.
4. The process of claim 3 , wherein a concentration of the copper ions is in a range from 30 g/L to 136 g/L.
5. The process of claim 1 , wherein the pretreatment solution further comprises an additive.
6. The process of claim 5 , wherein the additive is at least one selected from the group consisting of an accelerator, a suppressor, a leveler, a surfactant, and an acid.
7. The process of claim 6 , wherein a concentration of the accelerator in the pretreatment solution is in a range from 0 mL/L to about 50 mL/L.
8. The process of claim 6 , wherein a concentration of an active compound of the accelerator in the pretreatment solution is in a range from 0 ppm to 400 ppm.
9. The process of claim 6 , wherein a concentration of the suppressor in the pretreatment solution is in a range from 0 mL/L to about 40 mL/L.
10. The process of claim 6 , wherein a concentration of an active compound of the suppressor in the pretreatment solution is in a range from 0 ppm to 600 ppm.
11. The process of claim 6 , wherein a concentration of the leveler in the pretreatment solution is in a range from 0 mL/L to about 50 mL/L.
12. The process of claim 6 , wherein a concentration of an active compound of the leveler in the pretreatment solution is in a range from about 0 ppm to 500 ppm.
13. The process of claim 6 , wherein a concentration of the surfactant in the pretreatment solution is in a range from 0 wt % to about 3 wt %.
14. (canceled)
15. The process of claim 6 , wherein the acid is selected from the group consisting of sulfuric acid, methanesulfonic acid, and hydrochloric acid.
16. The process of claim 6 , wherein a concentration of the acid in the pretreatment solution is from 0 mL/L to about 40 mL/L.
17. The process of claim 1 , wherein the via or trench feature has an aspect ratio greater than 2:1.
18. The process of claim 1 , wherein the via or trench feature has a depth of more than 10 micrometers.
19. The process of claim 1 , further comprising:
rinsing a surface of the wafer with water or spin drying the wafer, to remove the pretreatment solution from the surface of the wafer.
20. A process for copper electroplating a via or trench feature on a wafer, the process comprising:
contacting a via or trench feature on a wafer obtained by the process of claim 1 with a copper electroplating solution; and
applying a current density to the wafer for a time sufficient to deposit a copper layer onto the wafer.
21. A copper electroplating pretreatment solution, comprising copper ions,
wherein a concentration of copper in the pretreatment solution is in a range from 10 g/L to 300 g/L.
22. A process for reducing electroplating voids and defects on a wafer, the process comprising:
contacting a via or trench feature on a wafer with a solution comprising copper ions, wherein a concentration of the copper ions in the solution is in a range from 10 g/L to 300 g/L, to obtain a pretreated wafer; and then,
copper electroplating the via or trench feature with a electroplating solution comprising copper,
wherein the copper concentration of the solution is higher than a copper concentration of the electroplating solution.
Priority Applications (1)
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US13/496,251 US20120175264A1 (en) | 2009-09-28 | 2010-09-22 | Wafer pretreatment for copper electroplating |
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US24616109P | 2009-09-28 | 2009-09-28 | |
PCT/EP2010/063929 WO2011036158A2 (en) | 2009-09-28 | 2010-09-22 | Wafer pretreatment for copper electroplating |
US13/496,251 US20120175264A1 (en) | 2009-09-28 | 2010-09-22 | Wafer pretreatment for copper electroplating |
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US13/496,251 Abandoned US20120175264A1 (en) | 2009-09-28 | 2010-09-22 | Wafer pretreatment for copper electroplating |
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US (1) | US20120175264A1 (en) |
EP (1) | EP2483456A2 (en) |
KR (1) | KR20120100947A (en) |
TW (1) | TWI499697B (en) |
WO (1) | WO2011036158A2 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140262799A1 (en) * | 2013-03-14 | 2014-09-18 | Rohm And Haas Electronic Materials Llc | Method of filling through-holes |
CN104762643A (en) * | 2014-12-17 | 2015-07-08 | 安捷利电子科技(苏州)有限公司 | Copper plating solution capable of realizing co-plating of through hole, blind hole and circuit |
US10508357B2 (en) | 2016-02-15 | 2019-12-17 | Rohm And Haas Electronic Materials Llc | Method of filling through-holes to reduce voids and other defects |
US10512174B2 (en) | 2016-02-15 | 2019-12-17 | Rohm And Haas Electronic Materials Llc | Method of filling through-holes to reduce voids and other defects |
CN114507886A (en) * | 2022-03-29 | 2022-05-17 | 四会富仕电子科技股份有限公司 | Hole-filling electroplating method |
Families Citing this family (3)
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US10214826B2 (en) * | 2013-01-29 | 2019-02-26 | Novellus Systems, Inc. | Low copper electroplating solutions for fill and defect control |
US20140299476A1 (en) * | 2013-04-09 | 2014-10-09 | Ebara Corporation | Electroplating method |
KR20200131909A (en) | 2018-04-09 | 2020-11-24 | 램 리써치 코포레이션 | Copper electrofill on non-copper liner layers |
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- 2010-09-22 EP EP10754951A patent/EP2483456A2/en not_active Withdrawn
- 2010-09-22 WO PCT/EP2010/063929 patent/WO2011036158A2/en active Application Filing
- 2010-09-22 KR KR1020127010605A patent/KR20120100947A/en not_active Application Discontinuation
- 2010-09-22 US US13/496,251 patent/US20120175264A1/en not_active Abandoned
- 2010-09-28 TW TW099132878A patent/TWI499697B/en not_active IP Right Cessation
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US10508357B2 (en) | 2016-02-15 | 2019-12-17 | Rohm And Haas Electronic Materials Llc | Method of filling through-holes to reduce voids and other defects |
US10512174B2 (en) | 2016-02-15 | 2019-12-17 | Rohm And Haas Electronic Materials Llc | Method of filling through-holes to reduce voids and other defects |
CN114507886A (en) * | 2022-03-29 | 2022-05-17 | 四会富仕电子科技股份有限公司 | Hole-filling electroplating method |
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EP2483456A2 (en) | 2012-08-08 |
WO2011036158A3 (en) | 2011-06-23 |
WO2011036158A2 (en) | 2011-03-31 |
KR20120100947A (en) | 2012-09-12 |
TWI499697B (en) | 2015-09-11 |
TW201129727A (en) | 2011-09-01 |
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Owner name: BASF SE, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LAI, CHIEN-HSUN;YANG, SHAO-MIN;HUANG, TZU-TSANG;REEL/FRAME:027892/0681 Effective date: 20100911 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |