WO2000030154A2 - Method to control film removal rates for improved polishing in metal cmp - Google Patents
Method to control film removal rates for improved polishing in metal cmp Download PDFInfo
- Publication number
- WO2000030154A2 WO2000030154A2 PCT/US1999/027092 US9927092W WO0030154A2 WO 2000030154 A2 WO2000030154 A2 WO 2000030154A2 US 9927092 W US9927092 W US 9927092W WO 0030154 A2 WO0030154 A2 WO 0030154A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- polishing
- oxidizing agent
- composition
- wafer
- metal
- Prior art date
Links
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 27
- 239000002184 metal Substances 0.000 title claims abstract description 27
- 238000000034 method Methods 0.000 title claims description 21
- 238000005498 polishing Methods 0.000 title claims description 21
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 29
- 230000004888 barrier function Effects 0.000 claims abstract description 18
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 239000007800 oxidant agent Substances 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000002245 particle Substances 0.000 claims abstract description 8
- 239000008119 colloidal silica Substances 0.000 claims abstract description 6
- 239000011164 primary particle Substances 0.000 claims abstract description 6
- 150000001875 compounds Chemical class 0.000 claims description 8
- 239000004065 semiconductor Substances 0.000 claims description 6
- 239000004094 surface-active agent Substances 0.000 claims description 5
- ICIWUVCWSCSTAQ-UHFFFAOYSA-M iodate Chemical group [O-]I(=O)=O ICIWUVCWSCSTAQ-UHFFFAOYSA-M 0.000 claims description 4
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical class [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 claims description 3
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical class OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 claims description 3
- ICIWUVCWSCSTAQ-UHFFFAOYSA-N iodic acid Chemical class OI(=O)=O ICIWUVCWSCSTAQ-UHFFFAOYSA-N 0.000 claims description 3
- 150000002823 nitrates Chemical class 0.000 claims description 3
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical class OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 claims description 3
- 150000002978 peroxides Chemical class 0.000 claims description 3
- JRKICGRDRMAZLK-UHFFFAOYSA-L persulfate group Chemical group S(=O)(=O)([O-])OOS(=O)(=O)[O-] JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 claims description 3
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims description 3
- 125000005498 phthalate group Chemical group 0.000 claims 2
- 239000002002 slurry Substances 0.000 description 16
- 239000000377 silicon dioxide Substances 0.000 description 8
- 239000002253 acid Substances 0.000 description 6
- 239000008139 complexing agent Substances 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 4
- 229910052721 tungsten Inorganic materials 0.000 description 4
- 239000010937 tungsten Substances 0.000 description 4
- 150000007942 carboxylates Chemical class 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000007517 polishing process Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 235000012431 wafers Nutrition 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RGHNJXZEOKUKBD-SQOUGZDYSA-N D-gluconic acid Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- LNTHITQWFMADLM-UHFFFAOYSA-N gallic acid Chemical compound OC(=O)C1=CC(O)=C(O)C(O)=C1 LNTHITQWFMADLM-UHFFFAOYSA-N 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical class OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- WQGWDDDVZFFDIG-UHFFFAOYSA-N pyrogallol Chemical compound OC1=CC=CC(O)=C1O WQGWDDDVZFFDIG-UHFFFAOYSA-N 0.000 description 2
- 241000894007 species Species 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- TUSDEZXZIZRFGC-UHFFFAOYSA-N 1-O-galloyl-3,6-(R)-HHDP-beta-D-glucose Natural products OC1C(O2)COC(=O)C3=CC(O)=C(O)C(O)=C3C3=C(O)C(O)=C(O)C=C3C(=O)OC1C(O)C2OC(=O)C1=CC(O)=C(O)C(O)=C1 TUSDEZXZIZRFGC-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OCUCCJIRFHNWBP-IYEMJOQQSA-L Copper gluconate Chemical class [Cu+2].OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C([O-])=O.OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C([O-])=O OCUCCJIRFHNWBP-IYEMJOQQSA-L 0.000 description 1
- RGHNJXZEOKUKBD-UHFFFAOYSA-N D-gluconic acid Natural products OCC(O)C(O)C(O)C(O)C(O)=O RGHNJXZEOKUKBD-UHFFFAOYSA-N 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- 239000001263 FEMA 3042 Substances 0.000 description 1
- LRBQNJMCXXYXIU-PPKXGCFTSA-N Penta-digallate-beta-D-glucose Natural products OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-PPKXGCFTSA-N 0.000 description 1
- 229920002253 Tannate Polymers 0.000 description 1
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 239000003945 anionic surfactant Substances 0.000 description 1
- 239000005380 borophosphosilicate glass Substances 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000003093 cationic surfactant Substances 0.000 description 1
- 239000002738 chelating agent Substances 0.000 description 1
- 150000001860 citric acid derivatives Chemical class 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- -1 for example Chemical class 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 229910021485 fumed silica Inorganic materials 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 229940074391 gallic acid Drugs 0.000 description 1
- 235000004515 gallic acid Nutrition 0.000 description 1
- 239000000174 gluconic acid Substances 0.000 description 1
- 235000012208 gluconic acid Nutrition 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 239000001630 malic acid Substances 0.000 description 1
- 235000011090 malic acid Nutrition 0.000 description 1
- 150000004701 malic acid derivatives Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229940079877 pyrogallol Drugs 0.000 description 1
- 238000006748 scratching Methods 0.000 description 1
- 230000002393 scratching effect Effects 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 235000015523 tannic acid Nutrition 0.000 description 1
- LRBQNJMCXXYXIU-NRMVVENXSA-N tannic acid Chemical compound OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-NRMVVENXSA-N 0.000 description 1
- 229940033123 tannic acid Drugs 0.000 description 1
- 229920002258 tannic acid Polymers 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical compound [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 description 1
- 239000011975 tartaric acid Substances 0.000 description 1
- 235000002906 tartaric acid Nutrition 0.000 description 1
- 239000002888 zwitterionic surfactant Substances 0.000 description 1
Classifications
-
- 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
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/32115—Planarisation
- H01L21/3212—Planarisation by chemical mechanical polishing [CMP]
-
- 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
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/31051—Planarisation of the insulating layers
- H01L21/31053—Planarisation of the insulating layers involving a dielectric removal step
Definitions
- the invention described pertains to the polishing methods and slurry formulations used in the planarization of integrated circuit surfaces containing various films, most particularly those of a metal, a barrier layer, and an insulator.
- CMP Chemical-Mechanical Planarization
- the method involves a two-step polishing process: in the first step, the majority of the conducting metal layer is removed without removing significant amounts of either the barrier layer or the dielectric layer.
- the metal interconnect remaining on the horizontal portions of the barrier layer and the barrier layer are removed without removing significant amounts of the dielectric layer, and without degrading the integrity of the remaining structure by significant removal of the remaining metal layer (commonly called “dishing” or “recess”) or removal of significant amounts of the remaining dielectric layer (commonly called “erosion”).
- Slurry compositions useful for accomplishing the second step polishing comprise: water, colloidal silica particles with a primary particle size between 10 and 100 nanometers and a surface area of 20 to 600 m 2 /g, an oxidizing agent, and, optionally, a surfactant or compound which acts to suppress the rate of removal of the dielectric insulating layer.
- any non-selective polishing composition which will have high removal rates for the metal may be used. It may have either high or low removal rates for the barrier layer and the insulating layer because the first step process will be stopped just before or just as the metal layer is entirely removed.
- the second step polishing process will use a slurry for which there is lower selectivity between the metal and the insulating layer, preferably between 10:1 and 1 :10 and more preferably between 3:1 and 1 :3, and most preferably about 1 :1.
- slurries comprised of colloidal silica particles with a primary particle size of 10 to 100 nanometers and a surface area of 20 to 600 m 2 /g provide second step selectivities within the desired range as well as a low level of scratches on the insulating layer surface, little erosion of the insulating layer surface, and little dishing of the metal surface.
- primary particle size is intended to mean the distance of the non-agglomerated or non-aggregated particle's largest dimension (either height, length or width).
- the surface area of the particles can be measured by the nitrogen adsorption method of S. Brunauer, P. H. Emmet and I. Teller, J. Am. Chemical Society, Volume 60, page 309 (1938) which is commonly referred to as BET measurement.
- the slurries useful for this invention also comprise an oxidizing agent.
- oxidizing agents are nitrates, iodates, chlorates, perchlorates, chlorites, sulphates, persulphates, peroxides, ozonated water, and oxygenated water.
- Oxidizing agents can be used in slurries for CMP at concentrations of about 0.01% to about 7% by weight. Generally they are used at concentrations of about 1% to about 7% by weight.
- An iodate is a preferred oxidizing agent.
- Dielectric oxide complexing agents which act to suppress the rate of removal of the dielectric oxide surface are described and claimed in US Patents Nos. 5,391,258; and 5,476,606 which are made part of this specification by reference.
- Acid species are defined as those functional groups having a dissociable proton. These include, but are not limited to, carboxylate, hydroxyl, sulfonic and phosphonic groups. Carboxylate and hydroxyl groups are preferred as these are present in the widest variety of effective species.
- Particularly effective are structures which possess two or more carboxylate groups with hydroxyl groups in an alpha position, such as straight chain mono- and di-carboxylic acids and salts including, for example, malic acid and malates, tartaric acid and tartarates and gluconic acid and gluconates. Also effective are tri- and polycarboxylic acids and salts with secondary or tertiary hydroxyl groups in an alpha position relative to a carboxylic group such as citric acid and citrates.
- a phthalate is used as the complexing agent.
- any surfactant whether it be an anionic, cationic, non-ionic or zwitter-ionic surfactant, might be effective in the compositions of this invention.
- Surfactants and complexing agents may be used in slurries for CMP at about 0.1% to about 7% by weight. Preferably they are used at about 0.5% to about 4% by weight.
- the rate of removal of barrier layer material can range anywhere from about 20 Angstroms/minute up to 2000 Angstroms/ minute or greater.
- the rates of removal of the metal layer and the insulating layer may be moderate to high (about 300 to about 2000 angstroms/minute) as long as the selectivity between them is in the range of l0:l to l :10.
- Tungsten sheet wafers and thermal oxide wafers were polished on a Westech 372 Polisher (available from IPEC Planar, Phoenix, AZ) on which an IC-1400-K Grooved pad (available from Rodel, Inc., Newark, DE) was used. Polishing conditions were: down force, 7.5 psi; table, 35 rpm; carrier, 35 rpm; slurry flow, 200 ml/min; polishing time, 2 min; rinse, 30 sec (polishing with DI water). The slurry comprised an abrasive at a concentration as listed below.
- the chemical part of the slurry comprised an oxidizing agent (an iodate at about 1% to about 7%) and a compound which complexes with dielectric oxide silica (a phthalate at about 2% to about 4%).
- the following table shows polishing rates for tungsten and the silicon oxide insulating material.
- colloidal silica abrasive provides the desired rates and selectivities for the second step process of this invention.
- alumina abrasives fumed and colloidal, do not provide the desired rates and selectivities.
- Metal layers for which the process and slurries of this invention might be useful include, but are not limited to, tungsten, aluminum, copper, platinum, palladium, gold, iridium and any combination or alloy thereof.
- Barrier layers for which the process and slurries of this invention might be useful include, but are not limited to, tantalum, tantalum nitride, titanium, titanium nitride, and any combinations thereof.
- Insulating or dielectric layers for which the process and slurries of this invention might be useful include, but are not limited to, PSG, BPSG, TEOS, Si0 2 , and any low-K polymeric material.
- the slurries of this invention may have a pH anywhere in the acidic, neutral, or alkaline range.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
A composition useful for a second step planarization of a metal, barrier layer, and a dielectric insulating layer structure is provided which comprises: water, colloidal silica particles with a primary particle size between 10 and 100 nanometers and a surface area of 20 to 600 m2/g, and an oxidizing agent.
Description
METHOD TO CONTROL FILM REMOVAL RATES FOR IMPROVED POLISHING IN METAL CMP
This application claims the benefit of Provisional Patent Application
Serial No. 60/108,656 filed November 16, 1998.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention described pertains to the polishing methods and slurry formulations used in the planarization of integrated circuit surfaces containing various films, most particularly those of a metal, a barrier layer, and an insulator.
Related Art
One of the critical requirements necessary in the production of increasingly complex and dense semiconductor structures is the ability to retain planarity. Without the ability to planarize, the complexity and density of the structures constructed on a semiconductor wafer are greatly limited. Chemical-Mechanical Planarization, or CMP, is an enabling technology in this area, since it has proved to be the most effective method used to planarize surface films on semiconductor substrates.
While the first applications of CMP technology focused on the polishing of dielectric films (i.e., Si02), polishing of metal structures used for circuit interconnects is increasing rapidly. Along with the increase in metal planarization is an inherent increase in the number of different films that are simultaneously polished. Most metal structures contain three different films: a conductive metal layer, a barrier (or liner) layer between the conductive metal layer and the adjacent dielectric layer, and a dielectric layer. It is often desirable for the removal rates of each film to differ from each other in order to induce planarity and maintain the integrity of the semiconductor structure during polishing. In a typical metal structure, for example, if the entire planarization step were to take place in one step of polishing, it would typically be desirable to have high removal rates of material for the metal and barrier layers, while having low removal rates for the dielectric layer.
However, while it is certainly desirable to limit the number of processing steps, there are often inherent difficulties associated with a one- step process that limit its usefulness. It has been found that the one-step process described above where there are low removal rates for the dielectric layer sometimes results in a polished dielectric layer with a very high level of scratches which are very difficult to remove.
SUMMARY OF THE INVENTION
A method is provided for polishing a composite semiconductor structure containing a conducting metal interconnect layer, an insulating dielectric layer, and a barrier layer between the two: most preferably, a tungsten metal layer, a silicon dioxide dielectric layer, and a barrier layer of titanium and/or titanium nitride. The method involves a two-step polishing process: in the first step, the majority of the conducting metal layer is removed without removing significant amounts of either the barrier layer or the dielectric layer. In the second step, the metal interconnect remaining on the horizontal portions of the barrier layer and the barrier layer are removed without removing significant amounts of the dielectric layer, and without degrading the integrity of the remaining structure by significant removal of the remaining metal layer (commonly called "dishing" or "recess") or removal of significant amounts of the remaining dielectric layer (commonly called "erosion"). Slurry compositions useful for accomplishing the second step polishing comprise: water, colloidal silica particles with a primary particle size between 10 and 100 nanometers and a surface area of 20 to 600 m2/g, an oxidizing agent, and, optionally, a surfactant or compound which acts to suppress the rate of removal of the dielectric insulating layer.
DESCRIPTION OF PREFERRED EMBODIMENTS
For a one-step process for planarizing a structure comprised of an insulating layer, a barrier layer, and a conductive metal layer, one would use a slurry which provides high removal rates for the metal and barrier layers and low removal rates for the insulating layer. In order to prevent dishing of the metal (plug, contact, or via) and scratching of the insulating layer, one must stop the polishing at the "just clear point", the point at
which the metal and barrier layers over the insulating layer have just been cleared from the surface of the insulating layer.
Since it is very difficult to determine and stop at the "just clear point", a planarization polishing process is proposed wherein there are two steps of polishing. In the first step any non-selective polishing composition which will have high removal rates for the metal may be used. It may have either high or low removal rates for the barrier layer and the insulating layer because the first step process will be stopped just before or just as the metal layer is entirely removed. The second step polishing process will use a slurry for which there is lower selectivity between the metal and the insulating layer, preferably between 10:1 and 1 :10 and more preferably between 3:1 and 1 :3, and most preferably about 1 :1.
It has surprisingly been found that slurries comprised of colloidal silica particles with a primary particle size of 10 to 100 nanometers and a surface area of 20 to 600 m2/g provide second step selectivities within the desired range as well as a low level of scratches on the insulating layer surface, little erosion of the insulating layer surface, and little dishing of the metal surface.
As used in this specification, "primary particle size" is intended to mean the distance of the non-agglomerated or non-aggregated particle's largest dimension (either height, length or width).
The surface area of the particles can be measured by the nitrogen adsorption method of S. Brunauer, P. H. Emmet and I. Teller, J. Am. Chemical Society, Volume 60, page 309 (1938) which is commonly referred to as BET measurement.
The slurries useful for this invention also comprise an oxidizing agent. Common oxidizing agents are nitrates, iodates, chlorates, perchlorates, chlorites, sulphates, persulphates, peroxides, ozonated water, and oxygenated water. Oxidizing agents can be used in slurries for CMP at concentrations of about 0.01% to about 7% by weight. Generally they are used at concentrations of about 1% to about 7% by weight. An iodate is a preferred oxidizing agent.
Dielectric oxide complexing agents which act to suppress the rate of removal of the dielectric oxide surface are described and claimed in US Patents Nos. 5,391,258; and 5,476,606 which are made part of this specification by reference. Farkas et al. in US Patent No. 5,614,444 disclose slurry additives which have a polar component and an apolar component. These additives passivate the dielectric surface and reduce its rate of removal. This patent (USP 5,614,444) is also made a part of this specification by reference.
Compounds which act as complexing agents or chelating agents for Si02 as described in U. S. Patent 5391258 and U. S. Patent 5476606 must have at least two acid groups present in the structure which can affect complexation to the oxide surface. Acid species are defined as those functional groups having a dissociable proton. These include, but are not limited to, carboxylate, hydroxyl, sulfonic and phosphonic groups. Carboxylate and hydroxyl groups are preferred as these are present in the widest variety of effective species. Particularly effective are structures which possess two or more carboxylate groups with hydroxyl groups in an alpha position, such as straight chain mono- and di-carboxylic acids and salts including, for example, malic acid and malates, tartaric acid and tartarates and gluconic acid and gluconates. Also effective are tri- and polycarboxylic acids and salts with secondary or tertiary hydroxyl groups in an alpha position relative to a carboxylic group such as citric acid and citrates. Also effective are compounds containing a benzene ring such as ortho di- and polyhydroxybenzoic acids and acid salts, phthalic acid and acid salts, pyrocatecol, pyrogallol, gallic acid and gallates and tannic acid and tannates. In the examples which follow a phthalate is used as the complexing agent.
It is believed that any surfactant, whether it be an anionic, cationic, non-ionic or zwitter-ionic surfactant, might be effective in the compositions of this invention.
Surfactants and complexing agents may be used in slurries for CMP at about 0.1% to about 7% by weight. Preferably they are used at about 0.5% to about 4% by weight.
Since the barrier layer is so thin, the rate of removal of barrier layer material can range anywhere from about 20 Angstroms/minute up to 2000
Angstroms/ minute or greater. The rates of removal of the metal layer and the insulating layer may be moderate to high (about 300 to about 2000 angstroms/minute) as long as the selectivity between them is in the range of l0:l to l :10.
EXAMPLE
Tungsten sheet wafers and thermal oxide wafers were polished on a Westech 372 Polisher (available from IPEC Planar, Phoenix, AZ) on which an IC-1400-K Grooved pad (available from Rodel, Inc., Newark, DE) was used. Polishing conditions were: down force, 7.5 psi; table, 35 rpm; carrier, 35 rpm; slurry flow, 200 ml/min; polishing time, 2 min; rinse, 30 sec (polishing with DI water). The slurry comprised an abrasive at a concentration as listed below. The chemical part of the slurry comprised an oxidizing agent (an iodate at about 1% to about 7%) and a compound which complexes with dielectric oxide silica (a phthalate at about 2% to about 4%). The following table shows polishing rates for tungsten and the silicon oxide insulating material.
Table 1
No. Abrasive W Wtt.. Primary Surface W RR, Si02 Selectivity
% % Particle Area, A/min RR, W:Si02
Size, nm m2/g A/min
1 fumed 5 5 1440 37 39:1 A1203
2 fumed 10 1434 50 29:1 A1203
3 fumed 5 20 65-100 1070 8 135:1 silica
4 fumed 10 20 65-100 1242 175:1 silica
5 colloidal 5 1527 232:1 A1203
6 colloidal 5 50 40-60 494 581 1 :1 silica
7 colloidal 10 50 40-60 721 890 1 :1 silica
8 colloidal 10 50 40-60 1236 1646 1 :1 silica
9 colloidal 10 12 180- 1847 887 2:1 silica 230
It is obvious from the above Table that colloidal silica abrasive provides the desired rates and selectivities for the second step process of this invention. A fumed silica with the tested oxidiation chemistry and pH,
even in the same size range and range of surface area, does not give the desired rates and selectivities. The alumina abrasives, fumed and colloidal, do not provide the desired rates and selectivities.
Metal layers for which the process and slurries of this invention might be useful include, but are not limited to, tungsten, aluminum, copper, platinum, palladium, gold, iridium and any combination or alloy thereof.
Barrier layers for which the process and slurries of this invention might be useful include, but are not limited to, tantalum, tantalum nitride, titanium, titanium nitride, and any combinations thereof.
Insulating or dielectric layers for which the process and slurries of this invention might be useful include, but are not limited to, PSG, BPSG, TEOS, Si02, and any low-K polymeric material.
Depending on the chemicals used, the slurries of this invention may have a pH anywhere in the acidic, neutral, or alkaline range.
Claims
1. A composition useful for a second step planarization of a metal, barrier layer, and a dielectric insulating layer structure comprising: water, colloidal silica particles with a primary particle size between 10 and 100 nanometers and a surface area of 20 to 600 m2/g, and an oxidizing agent.
2. A composition according to claim 1 wherein said oxidizing agent is from the group consisting of nitrates, iodates, chlorates, perchlorates, chlorites, sulphates, persulphates, peroxides, ozonated water, and oxygenated water.
3. A composition according to claim 2 wherein said oxidizing agent is an iodate.
4. A composition according to claim 1 further comprising a surfactant.
5. A composition according to claim 1 further comprising a compound which acts to suppress the rate of removal of the dielectric layer.
6. A composition according to claim 5 wherein said compound which acts to suppress the rate of removal of the dielectric layer is a phthalate.
7. A second-step planarization process for a metal, barrier layer, and dielectric insulating layer structure on a semiconductor wafer comprising:
(a) positioning said wafer in a polishing machine comprised of a polishing pad and a carrier for said wafer,
(b) contacting said wafer and said pad while maintaining a relative motion between said pad and said wafer and while a polishing composition is supplied to the interface between said wafer and said polishing pad, said polishing composition comprising: water, colloidal silica particles with a primary particle size between 10 and 100 nanometers and a surface area of 20 to 600 m2/g, and an oxidizing agent.
8. A method according to claim 7 wherein said oxidizing agent is from the group consisting of nitrates, iodates, chlorates, perchlorates, chlorites, sulphates, persulphates, peroxides, ozonated water, and oxygenated water.
9. A method according to claim 8 wherein said oxidizing agent is an iodate.
10. A method according to claim 7 wherein said composition further comprises a surfactant.
11. A method according to claim 7 wherein said composition further comprises a compound which acts to suppress the rate of removal of the dielectric layer.
12. A method according to claim 1 1 wherein said compound which acts to suppress the rate of removal of the dielectric layer is a phthalate.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10865698P | 1998-11-16 | 1998-11-16 | |
US60/108,656 | 1998-11-16 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000030154A2 true WO2000030154A2 (en) | 2000-05-25 |
Family
ID=22323400
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1999/027092 WO2000030154A2 (en) | 1998-11-16 | 1999-11-15 | Method to control film removal rates for improved polishing in metal cmp |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2000030154A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1111665A2 (en) * | 1999-12-21 | 2001-06-27 | Applied Materials, Inc. | Method of planarizing a substrate surface |
US6936543B2 (en) * | 2002-06-07 | 2005-08-30 | Cabot Microelectronics Corporation | CMP method utilizing amphiphilic nonionic surfactants |
DE19927286B4 (en) * | 1999-06-15 | 2011-07-28 | Qimonda AG, 81739 | Use of a grinding solution for the chemical mechanical polishing of a precious metal surface |
-
1999
- 1999-11-15 WO PCT/US1999/027092 patent/WO2000030154A2/en active Application Filing
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19927286B4 (en) * | 1999-06-15 | 2011-07-28 | Qimonda AG, 81739 | Use of a grinding solution for the chemical mechanical polishing of a precious metal surface |
EP1111665A2 (en) * | 1999-12-21 | 2001-06-27 | Applied Materials, Inc. | Method of planarizing a substrate surface |
EP1111665A3 (en) * | 1999-12-21 | 2004-01-02 | Applied Materials, Inc. | Method of planarizing a substrate surface |
US7041599B1 (en) | 1999-12-21 | 2006-05-09 | Applied Materials Inc. | High through-put Cu CMP with significantly reduced erosion and dishing |
US6936543B2 (en) * | 2002-06-07 | 2005-08-30 | Cabot Microelectronics Corporation | CMP method utilizing amphiphilic nonionic surfactants |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1064338B1 (en) | Chemical mechanical polishing slurry useful for copper substrates | |
EP1098948B1 (en) | Chemical mechanical polishing slurry useful for copper/tantalum substrate | |
US6217416B1 (en) | Chemical mechanical polishing slurry useful for copper/tantalum substrates | |
US6800218B2 (en) | Abrasive free formulations for chemical mechanical polishing of copper and associated materials and method of using same | |
JP5472049B2 (en) | Abrasives for chemical mechanical polishing | |
US6709316B1 (en) | Method and apparatus for two-step barrier layer polishing | |
US6316365B1 (en) | Chemical-mechanical polishing method | |
US20020019202A1 (en) | Control of removal rates in CMP | |
JP5596344B2 (en) | Silicon oxide polishing method using colloidal silica | |
KR101195349B1 (en) | Ruthenium cmp compositions and methods | |
EP0931118A1 (en) | Composition and method for polishing a composite comprising titanium | |
US6475069B1 (en) | Control of removal rates in CMP | |
US6530824B2 (en) | Method and composition for polishing by CMP | |
US7070485B2 (en) | Polishing composition | |
US6440857B1 (en) | Two-step CMP method and employed polishing compositions | |
US6693035B1 (en) | Methods to control film removal rates for improved polishing in metal CMP | |
KR100479804B1 (en) | Slurry compositions for metal cmp | |
WO2000030154A2 (en) | Method to control film removal rates for improved polishing in metal cmp | |
KR100725550B1 (en) | Cu CMP Slurry And Cu Polishing Method Using Thereof | |
KR100565426B1 (en) | Slurry for chemical and mechanical polishing of Tungsten line | |
KR100649859B1 (en) | CMP Slurry for Polishing of Cu Lines | |
KR100432637B1 (en) | CMP slurry for polishing copper wirings | |
KR100496501B1 (en) | Cmp slurry composition for a diffusion barrier comprising tantalum metal or its derivation in a copper interconnect | |
KR100552381B1 (en) | Slurry Composition for Chemical Mechanical Polishing of Metal | |
KR20030035637A (en) | Slurry for chemical and mechanical polishing of Cu lines |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A2 Designated state(s): CN JP KR SG |
|
AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
122 | Ep: pct application non-entry in european phase |