Source: http://www.google.com/patents/US7803203?dq=6,232,546
Timestamp: 2014-11-25 02:18:21
Document Index: 450449846

Matched Legal Cases: ['art 1', 'art 2', 'art 3', 'art 1', 'art 2', 'art 2', 'art 3', 'art 1', 'arts 2']

Patent US7803203 - Compositions and methods for CMP of semiconductor materials - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThe invention provides a composition for chemical-mechanical polishing. The composition comprises an abrasive, a first metal rate polishing modifier agent, a second metal rate polishing modifier agent, and a liquid carrier. In one embodiment, the first metal rate polishing modifier agent has a standard...http://www.google.com/patents/US7803203?utm_source=gb-gplus-sharePatent US7803203 - Compositions and methods for CMP of semiconductor materialsAdvanced Patent SearchPublication numberUS7803203 B2Publication typeGrantApplication numberUS 11/673,399Publication dateSep 28, 2010Filing dateFeb 9, 2007Priority dateSep 26, 2005Fee statusPaidAlso published asCN101506325A, CN101506325B, US8529680, US20070181535, US20100314576, WO2008027421A1Publication number11673399, 673399, US 7803203 B2, US 7803203B2, US-B2-7803203, US7803203 B2, US7803203B2InventorsFrancesco De Rege Thesauro, Steven Grumbine, Phillip Carter, Shoutian Li, Jian Zhang, David Schroeder, Ming-Shih TsaiOriginal AssigneeCabot Microelectronics CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (59), Non-Patent Citations (1), Classifications (11), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetCompositions and methods for CMP of semiconductor materialsUS 7803203 B2Abstract The invention provides a composition for chemical-mechanical polishing. The composition comprises an abrasive, a first metal rate polishing modifier agent, a second metal rate polishing modifier agent, and a liquid carrier. In one embodiment, the first metal rate polishing modifier agent has a standard reduction potential less than 0.34 V relative to a standard hydrogen electrode, and the second metal rate polishing modifier agent has a standard reduction potential greater than 0.34 V relative to a standard hydrogen electrode. In other embodiments, the first and second metal rate polishing modifier agents are different oxidizing agents.
1. A method of chemical-mechanical polishing comprising: (i) providing a substrate having at least two metals; (ii) providing a polishing composition comprising: (a) an abrasive, (b) a first metal polishing rate modifier agent having a standard reduction potential less than 0.34 V relative to a standard hydrogen electrode, wherein the first metal polishing rate modifier agent is a quinine an anthraquinone selected from the group consisting of 9,10-anthraquinone-1,8-disulfonic acid, 9,10-anthraquinone-1,5-disulfonic acid, 9, 10-anthraquinone-2, 6-disulfonic acid, and salts thereof, (c) a second metal polishing rate modifier agent having a standard reduction potential greater than 0.34 V relative to a standard hydrogen electrode, and (d) a liquid carrier; (iii) contacting the substrate with a polishing pad and the polishing composition; (iv) moving the substrate relative to the polishing pad and the polishing composition; and (v) abrading at least a portion of the substrate to polish the substrate.
2. The method of claim 1, wherein the second agent is an organic agent.
3. The method of claim 2, wherein the second agent is selected from the group consisting of dihydroxybenzoquinones, naphthoquinones, chloranilic acid, and dichloroindophenol.
4. The method of claim 2, wherein the second agent is selected from the group consisting of n-methylmorpholine-N-oxide and t-butyl peroxide.
5. The method of claim 1, wherein the second agent is an inorganic agent.
6. The method of claim 5, wherein the second agent is selected from the group consisting of hydrogen peroxide, iodate salts, persulfate salts, permanganate salts, I2, inorganic salts of iron (III), organic salts of iron (III), and potassium peroxymonosulfate.
7. The method of claim 5, wherein the second agent is selected from the group consisting of perchlorate salts, bromate salts, and cerium (I-V) sulfate.
8. The method of claim 1, wherein the composition further comprises a halide selected from the group consisting of chloride and bromide.
9. The method of claim 1, wherein the composition further comprises iodide.
10. A method of chemical-mechanical polishing comprising:
(i) providing a substrate having at least two metals;
(ii) providing a polishing composition comprising:
(b) a first metal polishing rate modifier agent, wherein the first agent is an anthraquinone is selected from the group consisting of 9,10-anthraquinone-1,8-disulfonic acid, 9,10-anthraquinone-1,5-disulfonic acid, 9,10-anthraquinone-2,6-disulfonic acid, and salts thereof,
(c) a second metal polishing rate modifier agent, wherein the second agent is selected from the group consisting of iodide, iodine, I2�malonamide3, and triiodide, and
(d) a liquid carrier;
(iii) contacting the substrate with a polishing pad and the polishing composition;
(vi) moving the substrate relative to the polishing pad and the polishing composition; and
(vii) abrading at least a portion of the substrate to polish the substrate.
11. The method of claim 10, wherein the second agent is I2�malonamide3.
12. The method of claim 10, wherein the second agent is iodide.
13. The method of claim 10, wherein the composition further comprises an oxidizing agent selected from the group consisting of hydrogen peroxide, iodate salts, persulfate salts, permanganate salts, bromate salts, potassium peroxymonosulfate, chloranilic acid, and n-methylmorpholine-N-oxide.
14. A method of chemical-mechanical polishing comprising:
(b) a first metal polishing rate modifier agent, wherein the first agent is an organic oxidizing agent comprising an anthraquinone is selected from the group consisting of 9,10-anthraquinone-1,8-disulfonic acid, 9,10-anthraquinone-1,5-disulfonic acid, 9,10-anthraquinone-2,6-disulfonic acid, and salts thereof,
(c) a second metal polishing rate modifier agent, wherein the second agent is an oxidizing agent present in a concentration below that of the first agent, and
15. The method of claim 14, wherein the first agent is present in a concentration of about 1 to about 60 mmol.
16. The method of claim 15, wherein the first agent is present in a concentration of about 1 to about 10 mmol.
17. The method of claim 14, wherein the second agent is an organic agent.
18. The method of claim 17, wherein the second agent is selected from the group consisting of dihydroxybenzoquinones, naphthoquinones, chloranilic acid, and dichloroindophenol, and I2�malonamide3.
19. The method of claim 17, wherein the second agent is selected from the group consisting of n-methylmorpholine-N-oxide and t-butyl peroxide.
20. The method of claim 18, wherein the second agent is I2�malonamide3.
21. The method of claim 14, wherein the second agent is an inorganic agent.
22. The method of claim 21, wherein the second agent is selected from the group consisting of hydrogen peroxide, iodate salts, persulfate salts, permanganate salts, I2, inorganic salts of iron (III), organic salts of iron (III), and potassium peroxymonosulfate.
23. The method of claim 21, wherein the second agent is selected from the group consisting of perchlorate salts, bromate salts, and cerium (IV) sulfate.
24. The method of claim 14, wherein the composition further comprises a halide selected from the group consisting of chloride and bromide.
25. The method of claim 14, wherein the composition further comprises iodide.
CROSS-REFERENCE TO RELATED APPLICATIONS This patent application is a continuation-in-part of copending U.S. patent application Ser. No. 11/235,765, filed Sep. 26, 2005, and claims priority to U.S. patent application Ser. No. 60/841,005, filed Aug. 30, 2006.
FIELD OF THE INVENTION This invention relates to polishing compositions and methods for polishing a substrate using the same. More particularly, this invention relates to chemical-mechanical polishing compositions suitable for polishing semiconductor surfaces.
BACKGROUND OF THE INVENTION Compositions and methods for chemical-mechanical polishing (CMP) of the surface of a substrate are well known in the art. Polishing compositions (also known as polishing slurries, CMP slurries, and CMP compositions) for CMP of metal-containing surfaces of semiconductor substrates (e.g., integrated circuits) typically contain an abrasive, various additive compounds, and the like.
One difficulty in using copper (Cu) in semiconductor devices is that copper diffuses into surrounding insulator material. To reduce the copper diffusion into the insulator material, and to aid in the adhesion of copper, a barrier layer is deposited in feature definitions prior to copper deposition. Barrier materials include, for example, tantalum (Ta), tantalum nitride (TaN), titanium (Ti), and titanium nitride (TiN). Following copper deposition, the excess copper and barrier layer is removed using CMP.
Current CMP processes and commercially available slurries for barrier layer removal are limited as to the useful chemical composition of the slurry because of the relatively inert nature of Ta. Consequently, polishing relies predominantly on strong mechanical abrasion. Stated somewhat differently, the currently available CMP processes and compositions with high solids concentrations for workpieces with Ta-containing barrier layers have very poor selectivity among the barrier layer, metal layer (Cu-based), and the interlayer dielectric (ILD) layer (silicon oxide-based), resulting in excessive concurrent removal of the metal and ILD layers.
BRIEF SUMMARY OF THE INVENTION The invention provides a chemical-mechanical polishing composition comprising (a) an abrasive, (b) a first metal polishing rate modifier agent, (c) a second metal polishing rate modifier agent, and (d) a liquid carrier.
In a second embodiment, the first metal polishing rate modifier agent is an organic oxidizing agent comprising a quinone moiety, and the second metal polishing rate modifier agent is selected from the group consisting of iodide, iodine, I2�malonamide3, and triiodide.
In a fourth embodiment, the first metal polishing rate modifier agent is an organic oxidizing agent comprising a quinone moiety, with the proviso that the first metal polishing rate modifier is not 1,2-napthoquinone-4-sulfonic acid, aminoanthraquinone sulfonic acid, or hydroquinone sulfonic acid, and the second metal polishing rate modifier agent is an oxidizing agent, with the proviso that the second metal polishing rate modifier agent is not the same as the first metal polishing rate modifier agent and is not potassium iodate or nitric acid.
DETAILED DESCRIPTION OF THE INVENTION The invention provides a CMP composition useful for polishing a substrate, preferably a semiconductor substrate that desirably contains at least two metals. The CMP composition contains (a) an abrasive, (b) a first metal polishing rate modifier agent, (c) a second metal polishing rate modifier agent, and (d) a liquid carrier.
The abrasive can be in any suitable formil. Typically, the abrasive is in the form of particles, which can be of any suitable size (i.e., the diameter of the smallest sphere encompassing the particle). For example, the abrasive can have a mean particle size of about 10 nm or more, e.g., about 20 nm or more, about 30 nm or more, or about 50 nm or more. Alternatively, or in addition, the abrasive can have a mean particle size of about 500 nm or less, e.g., about 300 nm or less, about 200 nm or less, or about 100 nm or less. Particle size can be determined by any suitable method, many of which are well known in the art, such as laser light scattering techniques.
The abrasive desirably is suspended in the CMP composition, more specifically in the liquid carrier of the CMP composition. When the abrasive is suspended in the CMP composition, the abrasive preferably is colloidally stable. The term �colloid� refers to the suspension of abrasive particles in the liquid carrier. �Colloidal stability� refers to the maintenance of that suspension over time. In the context of this invention, an abrasive is considered colloidally stable in a CMP composition if, when the CMP composition is placed into a 100 ml graduated cylinder and allowed to stand without agitation for a time of 2 hours, the difference between the concentration of abrasive in the bottom 50 ml of the graduated cylinder ([B] in terms of g/ml) and the concentration of abrasive in the top 50 ml of the graduated cylinder ([T] in terms of g/ml) divided by the initial concentration of abrasive in the CMP composition ([C] in terms of g/ml) is less than or equal to 0.5 (i.e., {[B]−[T]}/[C]≦0.5). The value of [B]−[T]/[C] desirably is less than or equal to 0.3, and preferably is less than or equal to 0.1.
The first and second metal polishing rate modifier agents are selected from the following pairs of first and second metal polishing rate modifier agents: (1) the first metal polishing rate modifier agent has a standard reduction potential less than 0.34 V relative to a standard hydrogen electrode, wherein the first metal polishing rate modifier agent is a quinone, and the second metal polishing rate modifier agent has a standard reduction potential greater than 0.34 V relative to a standard hydrogen electrode, (2) the first metal polishing rate modifier agent is an organic oxidizing agent comprising a quinone moiety, and the second metal polishing rate modifier agent is selected from the group consisting of iodide, iodine, I2�malonamide3, and triiodide, (3) the first metal polishing rate modifier agent is an organic oxidizing agent comprising a quinone moiety, and the second metal polishing rate modifier agent is an oxidizing agent present in a concentration below the concentration of the first metal polishing rate modifier agent, and (4) the first metal polishing rate modifier agent is an organic oxidizing agent comprising a quinone moiety, with the proviso that the first metal polishing rate modifier is not 1,2-napthoquinone-4-sullonic acid, aminoanthraquinone sulfonic acid, or hydroquinone sulfonic acid, and the second metal polishing rate modifier agent is an oxidizing agent, with the proviso that the second metal polishing rate modifier agent is not the same as the first metal polishing rate modifier agent and is not potassium iodate or nitric acid.
In the first embodiment, the first metal polishing rate modifier agent can be any suitable material having a standard reduction potential of about 0.34 V (the E0 value for CU2+→Cu0) or less relative to a standard hydrogen electrode. The second metal polishing rate modifier agent in the first embodiment can be any suitable material having a standard reduction potential greater than 0.34 V relative to a standard hydrogen electrode.
In the second embodiment, the first metal polishing rate modifier agent can be any suitable organic oxidizing agent comprising a quinone moiety. The second metal polishing rate modifier agent in the second embodiment can be any suitable agent selected from the group consisting of iodide, iodine, I2�malonamide3, and triiodide. The CMP composition of the second embodiment can optionally further comprise a second oxidizing agent.
Suitable organic oxidizing agents include, without limitation, chloranilic acid, organic peroxides, (e.g., t-butyl peroxide), n-methylmorpholine-N-oxide, dichloroindophenol, I2�malonamide3, and quinones, such as dihydroxyquinones, e.g., (2,5-dihydroxybenzoquinone), naphthoquinones (e.g., 1,2-naphthoquinone-4-sulfonic acid), and anthraquinones with one or more functional groups. The functional groups of anthraquinones primarily aid in enhancing the solubility of the anthraquinone in the CMP composition but also can affect the performance of the CMP composition in polishing a substrate. Suitable functional groups are, without limitation, sulfonates, phosphates, and amines. The anthraquinones can have a mixture of two or more different types of functional groups. Preferred functional groups for the anthraquinones are sulfonic acids. Thus, the organic oxidizing agent preferably is an anthraquinone disulfonic acid, such as 9,10-anthraquinone-1,8-disulfonic acid, 9,10-anthraquinone-1,5-disulfonic acid, 9,10-anthraquinone-2,6-disulfonic acid, and salts thereof.
Suitable inorganic oxidizing agents include, without limitation, hydrogen peroxide, potassium peroxymonosulfate, persulfate salts (e.g., ammonium monopersulfate, amnmonium dipersulfate, potassium monopersulfate, and potassium dipersulfate), periodate salts, (e.g., potassium periodate), perchlorate salts (e.g., potassium perchlorate), iodate salts (e.g., potassium iodate), iodine, triiodate salts, potassium permanganate, inorganic salts of iron (III) (e.g., ferric nitrate), organic salts of iron (III) (e.g., iron (III) malonate [Fe(III)(Ma)3]), cerium (IV) sulfate, bromate salts (e.g., potassium bromate), and chlorate salts. Preferably, when the second metal polishing rate modifier agent is an inorganic oxidizer, it is selected from iodate salts (e.g., potassium iodate), iodine, potassium permanganate, inorganic salts of iron (III) (e.g., ferric nitrate), bromate and chlorate salts, and persulfate salts. In some embodiments, the inorganic metal polishing rate modifier agent is not nitric acid.
The CMP composition can further comprise halide anions. Suitable halide anions include chloride, bromide, and iodide. A preferred halide anion in the CMP composition is iodide. The halide anion can be supplied by the use of any suitable salt in the CMP composition. Suitable salts for supplying halide ions include, for example, potassium, cesium, ammonium, magnesium, calcium, strontium, barium, and aluminum salts.
In addition to iodide, in some embodiments the CMP composition can contain iodine, I2�malonamide3, or triiodide. Iodine can be present as molecular iodine (I2) or as a soluble iodine adduct. Soluble iodine adducts are produced, for example, by combining I2 with a carbon acid. Preferably, the iodine adduct is I2�malonamide3.
The biocide can be any suitable biocide. A suitable biocide is an isothiazolinone composition such as KATHON� biocide, which is available from Roln and Haas (Philadelphia, Pa.). The CMP composition can comprise any suitable amount of a biocide, e.g., typically a biocidal amount.
The CMP composition can be prepared by any suitable technique, many of which are known to those skilled in the art. The CMP composition can be prepared in a batch or continuous process. Generally, the CMP composition can be prepared by combining the components thereof in any order, The term �component� as used herein includes individual ingredients (e.g., abrasives, acids, bases, metal polishing rate modifier agents, and the like), as well as any combination of ingredients. For example, an abrasive can be dispersed in water, and the metal polishing rate modifier agent, or the acid or base can be added, and mixed by any method that is capable of incorporating the components into the CMP composition. When oxidizing agents are added, some or all of the oxidizing agents may be added just prior to the initiation of polishing of the substrate. The components can be combined on the polishing platen by two or more delivery systems.
The CMP composition can be prepared as separate components that are mixed prior to use. The separate components can be combined in various ways. For example, a three part system can be made wherein the first part (part 1) contains the abrasive particles, the second part (part 2) contains the metal polishing rate modifier agents and water, and the third part (part 3) is water. As a further example, part 1 could comprise about 4 to 30 wt. % silica adjusted to a pH between 2 and 4, and part 2 could comprise two or more suitable metal polishing rate modifier agents The three parts then could be combined in various ways, for example by adding part 2 to part 3 (water) followed by adding part 1 into the mixture of parts 2 and 3. A skilled practitioner will recognize that the proportions and concentrations of the various parts can vary, depending on solubilities and stabilities of the components, such that the final concentrations of the components of the prepared CMP composition would be as described herein. An advantage of preparing the CMP composition from separate parts is to extend the shelf life of the product by keeping separate the abrasive particles from the other components. Another advantage is that most of the water need not be shipped from the manufacturer to the substrate fabrication facility, but could be added at the location where the polishing will occur, thereby reducing shipping costs.
The chemical-mechanical polishing method can be used to polish any suitable substrate, and is especially useful for polishing substrates comprising copper, copper-based alloys, tantalum, tantalum nitride, or combinations thereof. The invention also provides a method for selecting relative removal rates of these metals in chemical-nechanical polishing of a substrate. The method comprises altering the concentration of one or more of the metal polishing rate modifier agents such that the removal rate of a first metal is increased or decreased relative to the removal rate of a second metal. For example, increasing the concentration of a metal polishing rate modifier agent in a composition may increase the removal rate of copper and have no effect on the removal rate of tantalum. Therefore, in applications where it is desirable to remove only a small amount of copper relative to tantalum, a lower concentration of the second metal polishing rate modifier agent may be used. Conversely, in applications where it is desirable to remove equal amounts of copper and tantalum, a high concentration of the second metal polishing rate modifier agent may be used. In addition, the concentration and combination of the metal polishing rate modifier agents can be altered to effectively polish TiN.
A substrate can be planarized or polished with a CMP composition as described herein using any suitable polishing pad (e.g., polishing surface). Suitable polishing pads include, for example, woven and non-woven polishing pads, grooved or non-grooved pads, porous or non-porous pads, and the like. Moreover, suitable polishing pads can comprise any suitable polymer of varying density, hardness, thickness, compressibility, ability to rebound upon compression, and compression modulus. Suitable polymers include, for example, polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, coformed products thereof and mixtures thereof. Desirably, the polishing pads useful in the CMP method are pads comprising polyurethane polymers.
The CMP composition of the invention may be diluted at the point of use. In other words, the CMP composition of the invention may be diluted at the location of the chemical-mechanical polishing, e.g., at the substrate-polishing pad interface. Any suitable dilution can be used.�Dilution is done by adding an appropriate amount of a suitable liquid carrier, typically an aqueous diluent, with adequate mixing, to a concentrate of the CMP composition. The liquid carrier typically is water, preferably distilled or deionized water. In such an embodiment, the CMP composition concentrate can include the various components dispersed or dissolved in the liquid carrier, e.g., an aqueous solvent such as water, in amounts such that, upon dilution of the CMP composition concentrate with an appropriate amount of liquid carrier, e.g., aqueous solvent, each component of the CMP composition will be present in the CMP composition in an amount within the appropriate range for use.
EXAMPLE 1 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 9,10-anthraquinone-1,8-disulfonic acid (1,8-AQDSA) as a first metal polishing rate modifier agent and hydrogen peroxide as a second metal polishing rate modifier agent, in polishing substrates containing tantalum and copper.
Similar substrates comprising tantalum and copper were polished on a Logitech tabletop polisher with an EPIC� D100 pad (Cabot Microelectronics, Aurora, Ill.) with different polishing compositions (Polishing Compositions 1A-1E). The tool conditions were 102 rpm platen speed, 110 rpm carrier speed, 24.7 kPa (3.58 psi) down force, and 100 mL/min polishing composition flow.
Each of the polishing compositions contained 4 wt. % colloidal silica and 0.08 wt. % of the potassium salt of 1,8-AQDSA and were adjusted to pH 2.2 using nitric acid. Polishing Composition 1A (comparative) did not contain a second metal polishing rate modifier agent. Polishing Compositions 1B, 1C, 1D and 1E (invention) contained 25 ppm, 50 ppm, 100 ppm, and 500 ppm of hydrogen peroxide, respectively.
Copper Removal Rates with 1,8-AQDSA and H2O2 Polishing
EXAMPLE 2 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 1,8-AQDSA as a first metal polishing rate modifier agent and potassium iodate as a second metal polishing rate modifier agent, in polishing substrates containing tantalum and copper.
Copper and Tantalum Removal Rates with 1,8-AQDSA and KIO3 Polishing
KIO3 (ppm)
KIO3 (mM)
EXAMPLE 3 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 1,8-AQDSA as a first metal polishing rate modifier agent (1st MPRM agent) with either potassium iodate or 2,5-dihydroxybenzoquinone as a second metal polishing rate modifier agent (2nd MPRM agent), in polishing substrates containing tantalum and copper.
Similar substrates comprising tantalum and copper were polished on a MIRRA� polishing tool (Applied Materials) with a Polytex pad from Rodel with different polishing compositions (Polishing Compositions 3A-3C). The tool conditions included a 10.3 kPa (1.5 psi) down force.
2nd MPRM Agent
EXAMPLE 4 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 9,10-anthraquinone-1,5-disulfonic acid (1,5-AQDSA) as a first metal polishing rate modifier agent and potassium iodate as a second metal polishing rate modifier agent, in polishing substrates containing tantalum and copper.
Copper and Tantalum Removal Rates with 1,5-AQDSA and KIO3 Polishing
KIO3 Ta RR
Ta/Cu Rate
EXAMPLE 5 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 1,8-AQDSA as a first metal polishing rate modifier agent and 1,2-naphthoquinone-4-sulfonic acid (NQSA) as a second metal polishing rate modifier agent, in polishing substrates containing tantalum and copper.
Copper and Tantalum Removal Rates with 1,8-AQDSA and NQSA
EXAMPLE 6 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 1,8-AQDSA as a first metal polishing rate modifier agent and varying amounts of 2,5-dihydroxy-1,4-benzoquinone (DHBQ) as the second metal polishing rate modifier agent, in polishing substrates containing tantalum and copper.
Similar patterned wafers from Semitech containing Cu (5000 Å), Ta (250 Å), and TEOS (5000 Å) that had been previously polished with a copper polishing composition to clear the copper, were polished with Polishing Compositions 6A-6D on a MIRRA� polishing tool (Applied Materials) for 60 seconds.
DHBQ (ppm)
EXAMPLE 7 This example demonstrates the effectiveness of two metal polishing rate modifier agents, using 1,8-AQDSA as a first metal polishing rate modifier agent (1st MPRM agent) and ammonium persulfate (APS), potassium triiodide (KI3), potassium permanganate (KMnO4), or I2�malonamide3 as a second metal polishing rate modifier agent (2nd MPRM agent).
TEOS and copper blanket wafers were polished on a MIRRA� polishing tool (Applied Materials) with a IC1010 polishing pad with different polishing compositions (Polishing Compositions 7A-7H). The tool conditions were 103 rpm platen speed, 97 rpm carrier speed, 10.3 kPa (1.5 psi) down force, and 200 mL/min polishing composition flow,
2nd MPRM
7C (invention)
7D (invention)
KMnO4 600
7E (invention)
KMnO4 1000
7F (invention)
KI3 50
7G (invention)
KI3 150
7H (invention)
I2�malonamide3 20 (I2)/50
EXAMPLE 8 This example demonstrates the effectiveness of dual metal polishing rate modifier agents in the presence of a halide ion.
Copper blanket wafers were polished on a MIRRA� polishing tool (Applied Materials) with a IC1010 polishing pad with a polishing composition (Polishing Compositions 8A and 8B). The tool conditions were 103 rpm platen speed, 97 rpm carrier speed, 10.3 kPa (1.5 psi) down force, and 200 mL/min polishing composition flow.
Polihsing Composition 8A further comprised 0.08 wt. % of the potassium salt of 1,8-AQDSA and 20 ppm I2. The removal rate for copper was 128 Å/min. The use of halide anions as a second metal polishing rate modifier agent (such as iodide anions) in conjunction with a first metal polishing rate modifier agent (such as 1,8-AQDSA) can more effectively polish copper containing substrates as compared to the use of only one metal polishing rate modifier agent.
EXAMPLE 9 This example demonstrates the effectiveness of dual metal polishing rate modifier agents, using 1,8-AQDSA and iron (III) malonate [Fe(III)(Ma)3], in polishing substrates containing tantalum and copper.
Fe (III) (mM)
9A (comparative)
EXAMPLE 10 This example demonstrates the synergistic effect of an organic oxidizer as a first metal polishing rate modifier agent and a halide (iodide) as a second metal polishing rate modifier agent when used in a polishing composition containing two metal polishing rate modifier agents.
1,8-AQDSA (wt. %)
Halide (ppm)
10A (comparative)
10B (comparative)
EXAMPLE 11 This example demonstrates the effectiveness of a polishing composition containing two metal polishing rate modifier agents wherein 1,5-AQDSA is the first metal polishing rate modifier agent and a halide is the second metal polishing rate modifier agent; and of a polishing composition containing two metal polishing rate modifier agents and a halide ion as a third metal polishing rate modifier agent, wherein 1,5-AQDSA is the first metal polishing rate modifier agent, chloronilie acid is the second metal polishing rate modifier agent, and iodide, chloride, and bromide are the halide ions that represent the third metal polishing rate modifier agent, in polishing a substrate containing copper.
Copper blanket wafers were polished on a Logitech tabletop polisher with an EPIC� D100 pad (Cabot Microelectronics, Aurora, Ill.) with different polishing compositions (Polishing Compositions 11A-11K). The tool conditions were 100 rpm platen speed, 110 rpm carrier speed, 10.3 kPa (1.5 psi) down force, and 80 mL/min polishing composition flow.
The results show that KI, KCI, and KBr increase the Cu removal rates over the base polishing composition. Furhermore, the addition of chloranilic acid and KI allows even higher removal rates, and a large range of Cu removal rates can be achieve by varying the amounts of KI and chloranilic acid.
EXAMPLE 12 This example demonstrates the effectiveness of two metal polishing rate modifier agents and a halide as a third metal polishing rate modifier agent, using 1,5-AQDSA as the first metal polishing rate modifier agent, I2 as the second metal polishing rate modifier agent, and potassium iodide as the third polishing rate modifier agent, in polishing substrates containing copper.
The removal rates (KR) for copper for each of the chemical-mechanical polishing compositions were determined, and the results are summarized in Table 11.
1,5-AQDSA
KI (ppm)
EXAMPLE 13 This example further demonstrates the effectiveness of a first metal polishing rate modifier (1st MPRM) agent and a halide as a second metal polishing rate modifier (2nd MPRM) agent in polishing substrates containing tantalum and copper.
Similar substrates comprising tantalum and copper and TEOS were polished under the polishing conditions described in Example 11 with Polishing Compositions 13A-13H. Each of the polishing compositions contained 4 wt. % silica and 500 ppm BTA, and the pH was adjusted to 2.2 with nitric acid. Polishing Composition 13A (comparative) contained 0.2 wt. % 1,5-AQDSA. Polishing Compositions 13B-13D contained 0.1 wt. % 9,10-anthraquinone-2,6-disulfonic acid (2,6-AQSA) and 20 ppm, 40 ppm, and 100 ppm KI, respectively. Polishing Composition 13E contained 0.15 wt. % 2,6-AQDSA and 60 ppm KI. Polishing Compositions 13F and 13G contained 0.2 wt. % 2,6-AQDSA and 40 ppm KI and 100 ppm KI, respectively. Polishing Composition 13H contained 0.2 wt. % 1,5-AQDSA and 40 ppm KI.
1st MPRM
20 ppm KI
2,6-AQDSA
40 ppm KI
100 ppm KI 229
60 ppm KI
0.15 wt. %
100 ppm KI 252
EXAMPLE 14 This example further demonstrates the effectiveness of dual metal polishing rate modifier (MPRM) agents on pattern wafer polishing.
Field-Array
RR:Field
Array Oxide
0.125 mM KIO3 208
0.5 mM KIO3 237
2.5 mM KIO3 244
10 mM KIO3 259
14F (invention)
0.125 mM NQSA
0.5 mM NQSA
2.5 mM NQSA
14I (invention)
10 mM NQSA
14J (invention)
K2S2O8 14K
0.5 mM K2S2O8 298
2.5 mM K2S2O8 308
10 mM K2S2O8 1690
Fe(Ma)3 14O
0.5 mM Fe(Ma)3 311
14P (invention)
2.5 mM Fe(Ma)3 453
10 mM Fe(Ma)3 422
The results in Table 13 indicate that NQSA (1,4-naphthaquinone sulfonic acid) and potassium iodate provide superior results to potassium persulfate and Fe(Ma)3 (iron malonate) when used as metal polishing rate modifier agents. High ratios of Cu removal rate to the field-array oxide loss are desirable, Thus, under the above described conditions it is preferable for one of the metal polishing rate modifier agents to be selected from organic quinones and inorganic main group oxidizers, and not of the per- or transition metal-type oxidizers.
EXAMPLE 15 This example demonstrates the usefulness of the CMP composition of the invention in reducing defectivities when polishing substrates containing barrier materials with hard pads.
Two TEOS blanket wafers were polished on a MIRRA� polishing tool (Applied Materials) for 60 seconds with an EPIC� D100 pad (Cabot Microelectronics, Aurora, Ill.) (i.e., a hard pad) and a Politex pad (i.e., a soft pad) with different polishing compositions (Polishing Compositions 15A-15C). The tool conditions were 103 rpm platen speed, 97 rpm carrier speed, 10.3 kPa (1.5 psi) down force, and 200 mL/min polishing composition flow.
Polishing Composition 15A (comparative) contained 4 wt. % silica, 500 ppm BTA, and 800 ppm of 1,5-AQDSA, and the pH was adjusted to 2.2 with nitric acid. Polishing Composition 15B (invention) contained 4 wt. % silica, 500 ppm BTA, 800 ppm of 1,5-AQDSA, 17 ppm I2, and 34 ppm KI, and the pH was adjusted to 2.2 with nitric acid, Polishing Composition 15C (comparative) was a commercial hydrogen peroxide-based polishing composition having high solids content and high pH (i-Cue� 6678-A12, Cabot Microelectronics Corporation).
The wafers were inspected for defects using an SP1 KLA-Tencor (KLA-Tencor, Inc., San Jose, Calif.) dark field blanket wafer inspection tool. The output is a normal and oblique measurement count that is a measure of defectivity; higher defects correlate to higher normal and oblique measurement counts. The average normal and oblique counts are reported for each of the two wafers polished per experiment in Table 14.
Oblique Count
15A (comparative)
Politex (soft)
15C (comparative)
D100 (hard)
The results indicate that the polishing composition of the invention exhibits a low number of defects compared with the hydrogen peroxide-based polishing composition on the soft pad, The defectivity on the hard pad is higher, as expected, but surprisingly, still within an acceptable range.
EXAMPLE 16 This example further demonstrates the effectiveness of dual metal polishing rate modifier (MPRM) agents on pattern wafer polishing.
Similar substrates comprising thin films of Cu, Ta, or TiN on silicon were polished one Logitech tabletop polisher with a EPIC� D100 pad (Cabot Microelectronics, Aurora, Ill.) with different polishing compositions (Polishing Compositions 16AA-16BG). The tool conditions were 102 rpm platen speed, 110 rpm carrier speed, 10.3 kPa (1.5 psi) down force, and 100 mL/min polishing composition flow.
Each of the polishing compositions contains 4 wt. % colloidal silica (Nalco 50 nm diameter) and 500 ppm of BTA. Polishing compositions of the invention contained 5.4 mM 1,5-AQDSA as the first metal polishing rate modifier agent and a second metal polishing rate modifier agent as set out in Table 15, and the pH was adjusted to 2.8 with ammonium hydroxide. Comparative polishing compositions that do not contain a first metal polishing rate modifier agent were adjusted to a pH of 2,8 with nitric acid.
I2�malonamide3 15AD
I2�malonamide3 15AE
K2S2O8 15AF
K2S2O8 15AG
K2S2O8 15AH
K2S2O8 15AI
1.85 mM H2O2 155
1.85 mM H2O2 167
1.85 mM H2O2 143
1.85 mM H2O2 196
185 mM H2O2 299
185 mM H2O2 315
1.85 nM KIO3 459
1.85 nM KIO3 139
1.85 mN
I2�malonamide3 15AT
Chloranilic
Fe(NO3)3 15AW
Fe(NO3)3 15AX
KClO3 15AY
KClO3 15AZ
KBrO3 15BC
KBrO3 15BD
1.85 nM NMO
Ce(IV)(SO4)4 15BG
Ce(IV)(SO4)4 The results demonstrate that, when no metal polishing rate modifier is present, as in Polishing Composition AB, the polishing rates for Ta, Cu, and TiN are very low. When one metal polishing rate modifier agent is present, i.e., 1,5-AQDSA as in Polishing Composition AA, effective polishing rates for Ta are observed, but the polishing rates for Cu and TiN are low. In order to obtain acceptable rates on these two diverse materials, a combination of metal polishing rate modifier agents is required. Moreover, by carefully choosing the metal polishing rate modifier agents and their respective concentrations, the desired rates for Ta, Cu, and TiN can be selected and tuned.
Metal polishing rate modifier agents useful for polishing TiN include AQDSA, H2O2, iodate, oxone, I2�malonamide, chloranilic acid, perchlorate, t-BuOOH, and bromate. Metal polishing rate modifier agents useful for polishing copper include I2�malonamide3, persulfate, iodate, oxone, chloranilic acid, and bromate.
Preferred combinations for polishing compositions requiring tunable Ta, Cu, and TiN removal rates include AQDSA and I2�malonamide3, iodate, oxone, perchlorate, bromate, and n-methlylmorpholine-N-oxide.
EXAMPLE 17 This example demonstrates the effectiveness of dual metal polishing rate modifier agents 1,5-AQDSA and I2�malonamide3 in the presence of a second oxidizing agent.
The polishing conditions were the same as Example 16. Polishing Composition 16 contained 4 wt. % colloidal silica, 500 ppm BTA, 5.4 mM 1,5-AQDSA, 0.9 mM I2�malonamide3, and 185 mM H2O2.
The removal rates were 486 Å/min for copper, 775 Å/min for TiN, and 58 Å/min for Ta. Therefore, the presence of another metal polishing rate modifier agent in addition to 1,5-AQDSA and I2�malonamide3 significantly increases the polishing rate for the barrier layer TiN.
The use of the terms �a� and �an� and �the� and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context, The terms �comprising,� �having,� �including,� and �containing� are to be construed as open-ended terms (i.e., meaning �including, but not limited to,�) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context, The use of any and all examples, or exemplary language (e.g., �such as�) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
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