CN115056132A - Control method for dielectric and copper rate selection ratio in CMP process - Google Patents
Control method for dielectric and copper rate selection ratio in CMP process Download PDFInfo
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- CN115056132A CN115056132A CN202210281679.0A CN202210281679A CN115056132A CN 115056132 A CN115056132 A CN 115056132A CN 202210281679 A CN202210281679 A CN 202210281679A CN 115056132 A CN115056132 A CN 115056132A
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- 238000000034 method Methods 0.000 title claims abstract description 57
- 239000010949 copper Substances 0.000 title claims abstract description 48
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 47
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 45
- 238000005498 polishing Methods 0.000 claims abstract description 141
- 239000000243 solution Substances 0.000 claims description 98
- 239000002738 chelating agent Substances 0.000 claims description 63
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims description 40
- 239000004094 surface-active agent Substances 0.000 claims description 21
- 239000000203 mixture Substances 0.000 claims description 19
- 229940100555 2-methyl-4-isothiazolin-3-one Drugs 0.000 claims description 18
- DHNRXBZYEKSXIM-UHFFFAOYSA-N chloromethylisothiazolinone Chemical compound CN1SC(Cl)=CC1=O DHNRXBZYEKSXIM-UHFFFAOYSA-N 0.000 claims description 18
- BEGLCMHJXHIJLR-UHFFFAOYSA-N methylisothiazolinone Chemical compound CN1SC=CC1=O BEGLCMHJXHIJLR-UHFFFAOYSA-N 0.000 claims description 18
- 230000000844 anti-bacterial effect Effects 0.000 claims description 16
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 15
- 239000003899 bactericide agent Substances 0.000 claims description 15
- 239000008139 complexing agent Substances 0.000 claims description 14
- 239000008367 deionised water Substances 0.000 claims description 14
- 229910021641 deionized water Inorganic materials 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims description 12
- 229940051841 polyoxyethylene ether Drugs 0.000 claims description 12
- 229920000056 polyoxyethylene ether Polymers 0.000 claims description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 8
- CHHHXKFHOYLYRE-UHFFFAOYSA-M 2,4-Hexadienoic acid, potassium salt (1:1), (2E,4E)- Chemical compound [K+].CC=CC=CC([O-])=O CHHHXKFHOYLYRE-UHFFFAOYSA-M 0.000 claims description 6
- WBIQQQGBSDOWNP-UHFFFAOYSA-N 2-dodecylbenzenesulfonic acid Chemical compound CCCCCCCCCCCCC1=CC=CC=C1S(O)(=O)=O WBIQQQGBSDOWNP-UHFFFAOYSA-N 0.000 claims description 6
- 229940100484 5-chloro-2-methyl-4-isothiazolin-3-one Drugs 0.000 claims description 6
- 239000005711 Benzoic acid Substances 0.000 claims description 6
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 claims description 6
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 6
- DMSMPAJRVJJAGA-UHFFFAOYSA-N benzo[d]isothiazol-3-one Chemical compound C1=CC=C2C(=O)NSC2=C1 DMSMPAJRVJJAGA-UHFFFAOYSA-N 0.000 claims description 6
- 235000010233 benzoic acid Nutrition 0.000 claims description 6
- 229960004365 benzoic acid Drugs 0.000 claims description 6
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 6
- 229940060296 dodecylbenzenesulfonic acid Drugs 0.000 claims description 6
- SYELZBGXAIXKHU-UHFFFAOYSA-N dodecyldimethylamine N-oxide Chemical compound CCCCCCCCCCCC[N+](C)(C)[O-] SYELZBGXAIXKHU-UHFFFAOYSA-N 0.000 claims description 6
- 229910017053 inorganic salt Inorganic materials 0.000 claims description 6
- -1 kason Chemical compound 0.000 claims description 6
- 235000010241 potassium sorbate Nutrition 0.000 claims description 6
- 239000004302 potassium sorbate Substances 0.000 claims description 6
- 229940069338 potassium sorbate Drugs 0.000 claims description 6
- 229940083575 sodium dodecyl sulfate Drugs 0.000 claims description 6
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 6
- 239000003381 stabilizer Substances 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 6
- 239000003002 pH adjusting agent Substances 0.000 claims description 5
- 238000004448 titration Methods 0.000 claims description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 4
- 229910017604 nitric acid Inorganic materials 0.000 claims description 4
- 239000012895 dilution Substances 0.000 claims description 3
- 238000010790 dilution Methods 0.000 claims description 3
- 230000003115 biocidal effect Effects 0.000 claims 1
- 239000003139 biocide Substances 0.000 claims 1
- 238000007865 diluting Methods 0.000 claims 1
- 239000002002 slurry Substances 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 7
- 239000000126 substance Substances 0.000 abstract description 4
- 238000009776 industrial production Methods 0.000 abstract description 2
- 239000003795 chemical substances by application Substances 0.000 abstract 1
- 230000001276 controlling effect Effects 0.000 description 6
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000013522 chelant Substances 0.000 description 3
- 229910001431 copper ion Inorganic materials 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 238000005381 potential energy Methods 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- VUWCWMOCWKCZTA-UHFFFAOYSA-N 1,2-thiazol-4-one Chemical class O=C1CSN=C1 VUWCWMOCWKCZTA-UHFFFAOYSA-N 0.000 description 1
- WFJFGMLKAISFOZ-UHFFFAOYSA-N 1-amino-3-iminourea Chemical compound NN=C(O)N=N WFJFGMLKAISFOZ-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000006748 scratching Methods 0.000 description 1
- 230000002393 scratching effect Effects 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/005—Control means for lapping machines or devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/005—Control means for lapping machines or devices
- B24B37/0056—Control means for lapping machines or devices taking regard of the pH-value of lapping agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B57/00—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents
- B24B57/02—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D11/00—Control of flow ratio
- G05D11/02—Controlling ratio of two or more flows of fluid or fluent material
- G05D11/035—Controlling ratio of two or more flows of fluid or fluent material with auxiliary non-electric power
- G05D11/08—Controlling ratio of two or more flows of fluid or fluent material with auxiliary non-electric power by sensing concentration of mixture, e.g. measuring pH value
-
- 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
- H01L21/7684—Smoothing; Planarisation
Abstract
The invention provides a control method for the rate selection ratio of a medium to copper in a CMP process, and relates to the field of chemical mechanical polishing. A control method for the selective ratio of the dielectric to the copper rate in the CMP process comprises the following steps: adjusting the pH value of the polishing solution to 9.0-11.5 by adopting a pH value regulator; adding the polishing solution into a polishing machine to polish the graphic sheet to obtain a finished product; wherein the polishing conditions are as follows: the working pressure is 1-5Psi, the rotation speed of the polishing head is 88-108r/min, the rotation speed of the polishing disc is 100-. The pH value of the polishing solution is adjusted by selecting the pH value adjusting agent, so that the removal rate ratio of the medium and copper of different materials is controlled, the rate selection ratio is controllable and adjustable, and the control method is simple, accurate in precision and suitable for the requirements of large-scale industrial production.
Description
Technical Field
The invention relates to the field of chemical mechanical polishing, in particular to a method for controlling the rate selection ratio of a medium to copper in a CMP (chemical mechanical polishing) process.
Background
In the development of a very Large Scale Integrated circuit (GLSI), the area occupied by a chip is continuously reduced, the feature size is reduced, in order to reduce interconnection delay and reduce the line length, an advanced technology node Integrated circuit adopts a multilayer metal interconnection structure, and the requirement for planarization of the surface of a graphic sheet is more and more strict. Chemical Mechanical Polishing (CMP) is the only method that can simultaneously achieve local and global planarization, and for a copper barrier layer, CMP is performed, and the dielectric and copper rates together determine the planarization effect of the patterned wafer surface. However, in advanced integrated circuit fabrication, different copper and dielectric thicknesses of different interconnect layers vary, and thus different dielectric-to-copper rate ratios are required during CMP to achieve high planarization of the patterned surface.
Currently, different media to copper rate ratios are typically achieved by polishing with polishing solutions of different formulations. However, as the variety of integrated circuits is varied, the parameter requirements are varied, and it is increasingly difficult to adjust the dielectric-to-copper rate ratio by the recipe for large-scale integrated circuit manufacturing, and the accuracy is also difficult to meet the requirements.
Disclosure of Invention
The invention aims to provide a method for controlling the selective ratio of the medium to the copper rate in the CMP process, which controls the removal rate ratio of the medium to the copper by adjusting the pH value without adjusting the formula of a polishing solution.
The technical problem to be solved by the invention is realized by adopting the following technical scheme.
The embodiment of the application provides a control method for the selection ratio of the medium to the copper rate in the CMP process, which comprises the following steps:
adjusting the pH value of the polishing solution to 9.0-11.5 by adopting a pH value regulator; adding the polishing solution into a polishing machine to polish the graphic sheet to obtain a finished product;
wherein the polishing conditions are as follows: the working pressure is 1-5Psi, the rotation speed of the polishing head is 88-108r/min, the rotation speed of the polishing disc is 100-.
Compared with the prior art, the embodiment of the invention has at least the following advantages or beneficial effects:
the control method of the invention selects the pH value regulator to adjust the pH value of the polishing solution, and further controls the removal rate ratio of the medium and copper of different materials, and the rate selection ratio is controllable and adjustable. The pH value of the polishing solution determines the existence environment of the polishing solution and components inside the polishing solution, and the existence form of the components in the polishing solution in the planarization process, the stability of the alkaline polishing solution mainly depends on the stability of silica sol in the polishing solution, the pH value is the most main factor influencing the agglomeration of the silica sol, and when the pH value is 7-9, the silica sol is easy to agglomerate; when the pH value is 9-11.5, the colloidal particle stability of the silica sol reaches the highest peak, and meanwhile, the dispersion characteristic is also the best; when the pH is more than 11.5, the spherical abrasive particles start to dissolve, and thus it is important to control the pH of the polishing liquid to stabilize the polishing rate. The method has the advantages that for different products and different thicknesses of copper and media of different interconnection layers, different removal rate ratios of the media and the copper are inconvenient to realize by reconfiguring the formula of the polishing solution every time, the pH value of the polishing solution is directly adjusted, the polishing solution does not need to be replaced again, and different removal rate ratios of the media and the copper can be achieved under different pH values so as to adapt to the rate selection ratio of the media and the copper required by different materials in the CMP process and further realize high planarization of the surface of the graph.
In addition, the FA/O type chelating agent contained in the polishing solution is a polyhydroxy polyamino base macromolecular organic matter, the reaction with copper is slow under a static condition when the pH value is 9.0-11.5, and under the CMP condition, the energy provided by the system overcomes the reaction potential energy, so that the reaction is fast and accelerated, the FA/O type chelating agent can efficiently react with copper ions to generate a chelate, so that the high removal rate of copper is realized, the polishing rate is accelerated, and because the surface of a polishing sheet is different in height, the energy at the high position is higher than the energy at the low position, so that the difference of the high and low positions is caused, and the surface is flattened after polishing.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a graph showing the effect of pH on the removal rate ratio of medium to copper in a polishing solution.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to specific examples.
The embodiment of the invention provides a method for controlling the selection ratio of a medium to a copper rate in a CMP process, which comprises the following steps:
adjusting the pH value of the polishing solution to 9.0-11.5 by adopting a pH value regulator; adding the polishing solution into a polishing machine to polish the graphic sheet to obtain a finished product;
wherein the polishing conditions are as follows: the working pressure is 1-5Psi, the rotation speed of the throwing head is 88-108r/min, the rotation speed of the throwing disc is 100-110r/min, and the flow rate of the polishing solution is 200-300 ml/min.
In the above embodiment, the control method selects the pH adjuster to adjust the pH of the polishing solution, and further controls the removal rate ratio of the medium and copper of different materials, and the rate selection ratio is controllable and adjustable. The pH value of the polishing solution determines the existence environment of the polishing solution and components inside the polishing solution, and the existence form of the components in the polishing solution in the planarization process, the stability of the alkaline polishing solution mainly depends on the stability of silica sol in the polishing solution, the pH value is the most main factor influencing the agglomeration of the silica sol, and when the pH value is 7-9, the silica sol is easy to agglomerate; when the pH value is 9-11.5, the colloidal particle stability of the silica sol reaches the highest peak, and meanwhile, the dispersion characteristic is also the best; when the pH is more than 11.5, the spherical abrasive particles start to dissolve, and thus it is important to control the pH of the polishing liquid to stabilize the polishing rate. The method has the advantages that for different products and different thicknesses of copper and media of different interconnection layers, different removal rate ratios of the media and the copper are inconvenient to realize by reconfiguring the formula of the polishing solution every time, the pH value of the polishing solution is directly adjusted, the polishing solution does not need to be replaced again, and different removal rate ratios of the media and the copper can be achieved under different pH values so as to adapt to the rate selection ratio of the media and the copper required by different materials in the CMP process and further realize high planarization of the surface of the graph.
In some embodiments of the present invention, the pH adjuster is one or more of sulfuric acid, nitric acid, hydrochloric acid, potassium hydroxide, FA/O1 chelating agent, FA/O2 chelating agent, FA/O3 chelating agent, FA/O4 chelating agent, and FA/O5 chelating agent. Sulfuric acid, nitric acid and hydrochloric acid are used as acidic regulators, potassium hydroxide, FA/O1 chelating agents, FA/O2 chelating agents, FA/O3 chelating agents, FA/O4 chelating agents and FA/O5 chelating agents are used as alkaline regulators, the pH value of the polishing solution is directly regulated through the acidic or alkaline pH value regulators, and the control method is simple.
In some embodiments of the invention, the specific adjustment steps are: and (3) taking a pH value regulator by using an acid burette or a basic burette, holding the non-scale part at the upper end of the burette to start titration in the polishing solution, measuring the pH value of the polishing solution by using an acidimeter, and continuing the titration until the read number is stable until the specified pH value is displayed. The pH value is adjusted by means of titration of the pH value regulator and direct measurement of the pH value by an acidimeter, and the method is accurate in precision, simple and easy to implement.
In some embodiments of the present invention, the polishing solution comprises the following components by mass percent: 3-10% of silica sol, 0.02-2% of complexing agent, 0.03-2% of bactericide, 0.0001-3% of surfactant and the balance of deionized water. The components of the polishing solution do not contain corrosion inhibitors, so the polishing solution does not corrode equipment and pollute the environment.
In some embodiments of the present invention, the silica sol has a particle size of 30nm to 200 nm. The nano-scale silica sol abrasive can effectively improve the polishing removal rate and the surface quality.
In some embodiments of the present invention, the complexing agent is one or more of a FA/O1 type chelating agent, a FA/O2 type chelating agent, a FA/O3 type chelating agent, a FA/O4 type chelating agent, and a FA/O5 type chelating agent. The FA/O type chelating agent is a polyhydroxy polyamino basic macromolecular organic matter, which slowly reacts with copper under a static condition when the pH value is 9.0-11.5, and under the CMP condition, the energy provided by the system overcomes the reaction potential energy, so that the reaction is quickly accelerated, the FA/O type chelating agent can efficiently react with copper ions to generate a soluble chelate, thereby realizing high copper removal rate and accelerating polishing rate, and because the surface of a polishing sheet has different heights, the energy at the high position is higher than the energy at the low position, the difference of the high and low positions is generated, and the surface is flattened after polishing.
In some embodiments of the present invention, the bactericide is one or more of methylisothiazolinone, kason, potassium sorbate, benzoic acid, 5-chloro-2-methyl-4-isothiazolin-3-one, and 1-2 benzisothiazolin-3-one. The bactericide can play a role in sterilizing the polishing solution, can effectively prolong the service life of the polishing solution,
in some embodiments of the present invention, the casone is a mixture of 2-methyl-4-isothiazolin-3-one, 2-methyl-5-chloro-4-isothiazolin-3-one and an inorganic salt stabilizer, wherein the mass ratio of 2-methyl-4-isothiazolin-3-one to 2-methyl-5-chloro-4-isothiazolin-3-one is (3-4): 1. The carbazone serving as the isothiazolinone derivative is a non-oxidative bactericide, has broad bactericidal performance and has a good inhibition effect on various microorganisms.
In some embodiments of the present invention, the surfactant is one or more selected from FA/O surfactant, dodecyl dimethyl amine oxide, sodium dodecyl sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and isomeric fatty alcohol-polyoxyethylene ether. The surfactant can improve the dispersity of the silica sol, so that the polishing solution cannot generate a gel phenomenon, the possibility of generating large agglomerated particles is reduced, the surface roughness is reduced, the defects of scratching and the like caused by the large particles on the surface are avoided, and the surface quality after polishing is improved.
In some embodiments of the present invention, the method for preparing the polishing solution comprises the following steps: taking silica sol, and adding deionized water for dilution to obtain a silica sol solution; mixing the complexing agent, the bactericide and the surfactant, adding deionized water for dilution, adding the silica sol solution, and uniformly stirring to obtain the polishing solution. The preparation method is simple and convenient in process, can be used for preparing the polishing solution with good stability, and is suitable for the requirement of large-scale industrial production.
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
A method for controlling the dielectric to copper rate selectivity in a CMP process, comprising the steps of:
preparing 10kg of polishing solution: taking 10% by mass of silica sol with the particle size of 100nm, and adding deionized water to dilute the silica sol to 5kg to obtain a silica sol solution; mixing 2 mass percent of complexing agent, 1 mass percent of bactericide and 1.6 mass percent of surfactant, adding deionized water to dilute the mixture to 5kg, adding the silica sol solution, and uniformly stirring to obtain polishing solution for later use;
the complexing agent is a mixture of FA/O1 chelating agent, FA/O2 chelating agent, FA/O3 chelating agent, FA/O4 chelating agent and FA/O5 chelating agent;
the bactericide is a mixture of methylisothiazolinone, kason, potassium sorbate, benzoic acid, 5-chloro-2-methyl-4-isothiazolin-3-one and 1-2 benzisothiazolin-3-one, wherein the kason is a mixture of 2-methyl-4-isothiazolin-3-one, 2-methyl-5-chloro-4-isothiazolin-3-one and an inorganic salt stabilizer, and the mass ratio of the 2-methyl-4-isothiazolin-3-one to the 2-methyl-5-chloro-4-isothiazolin-3-one is 3: 1;
the surfactant is prepared by mixing FA/O surfactant, dodecyl dimethyl amine oxide, sodium dodecyl sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and heterogeneous fatty alcohol-polyoxyethylene ether;
preparing a pH value regulator: mixing sulfuric acid, an FA/O2 chelating agent and an FA/O5 chelating agent for later use;
adjusting the pH value: taking a pH value regulator by using an acid burette or a basic burette, holding the non-scale part at the upper end of the burette to start to titrate into the polishing solution, simultaneously measuring the polishing solution by using an acidimeter, and continuing to titrate after the reading is stable until the pH value is 9.98, and marking as polishing solution S1;
polishing: the polishing solution S1 was added to a Universal-300Plus type polisher manufactured by Waschanheinaceae at a working pressure of Z1: 4.76Psi, Z2: 2.01Psi, Z3: 1.82Psi, Z4: 1.92Psi, Z5: 1.63 Psi; the rotating speed of the throwing head is 98 r/min; the rotating speed of the polishing disc is 105 r/min; polishing was carried out at a flow rate of 250ml/min, wherein the working pressures Z1 to Z5 were a set of pressures applied when the projectile was from the outside to the center of the projectile.
Example 2
A control method for the selective ratio of the dielectric to the copper rate in the CMP process comprises the following steps:
preparing 10kg of polishing solution: taking 10% by mass of silica sol with the particle size of 100nm, and adding deionized water to dilute the silica sol to 5kg to obtain a silica sol solution; mixing 2 mass percent of complexing agent, 1 mass percent of bactericide and 1.6 mass percent of surfactant, adding deionized water to dilute the mixture to 5kg, adding the silica sol solution, and uniformly stirring to obtain polishing solution for later use;
the complexing agent is a mixture of FA/O1 chelating agent, FA/O2 chelating agent, FA/O3 chelating agent, FA/O4 chelating agent and FA/O5 chelating agent;
the bactericide is a mixture of methylisothiazolinone, kason, potassium sorbate, benzoic acid, 5-chloro-2-methyl-4-isothiazolin-3-one and 1-2 benzisothiazolin-3-one, wherein the kason is a mixture of 2-methyl-4-isothiazolin-3-one, 2-methyl-5-chloro-4-isothiazolin-3-one and an inorganic salt stabilizer, and the mass ratio of the 2-methyl-4-isothiazolin-3-one to the 2-methyl-5-chloro-4-isothiazolin-3-one is 3: 1;
the surfactant is prepared by mixing FA/O surfactant, dodecyl dimethyl amine oxide, sodium dodecyl sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and heterogeneous fatty alcohol-polyoxyethylene ether;
preparing a pH value regulator: mixing nitric acid, potassium hydroxide, an FA/O1 chelating agent and an FA/O2 chelating agent for later use;
adjusting the pH value: taking a pH value regulator by using an acid burette or a basic burette, holding the non-scale part at the upper end of the burette to start to titrate into the polishing solution, simultaneously measuring the polishing solution by using an acidimeter, and continuing to titrate after the reading is stable until the pH value is displayed to 10.35, which is marked as polishing solution S2;
polishing: the polishing solution S2 was added to a Universal-300Plus type polisher manufactured by Waishika, Inc., under a working pressure of Z1: 4.76Psi, Z2: 2.01Psi, Z3: 1.82Psi, Z4: 1.92Psi, Z5: 1.63 Psi; the rotating speed of the throwing head is 98 r/min; the rotating speed of the polishing disc is 105 r/min; polishing was carried out under a polishing liquid flow rate of 250 ml/min.
Example 3
A method for controlling the dielectric to copper rate selectivity in a CMP process, comprising the steps of:
preparing 10kg of polishing solution: taking 10% by mass of silica sol with the particle size of 100nm, and adding deionized water to dilute the silica sol to 5kg to obtain a silica sol solution; mixing 2 mass percent of complexing agent, 1 mass percent of bactericide and 1.6 mass percent of surfactant, adding deionized water to dilute the mixture to 5kg, adding the silica sol solution, and uniformly stirring to obtain polishing solution for later use;
the complexing agent is a mixture of FA/O1 chelating agent, FA/O2 chelating agent, FA/O3 chelating agent, FA/O4 chelating agent and FA/O5 chelating agent;
the bactericide is a mixture of methylisothiazolinone, kason, potassium sorbate, benzoic acid, 5-chloro-2-methyl-4-isothiazolin-3-one and 1-2 benzisothiazolin-3-one, wherein the kason is a mixture of 2-methyl-4-isothiazolin-3-one, 2-methyl-5-chloro-4-isothiazolin-3-one and an inorganic salt stabilizer, and the mass ratio of the 2-methyl-4-isothiazolin-3-one to the 2-methyl-5-chloro-4-isothiazolin-3-one is 3: 1;
the surfactant is prepared by mixing FA/O surfactant, dodecyl dimethyl amine oxide, sodium dodecyl sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and heterogeneous fatty alcohol-polyoxyethylene ether;
preparing a pH value regulator: mixing hydrochloric acid, potassium hydroxide, an FA/O2 chelating agent, an FA/O3 chelating agent and an FA/O5 chelating agent for later use;
adjusting the pH value: taking a pH value regulator by using an acid burette or a basic burette, holding the non-scale part at the upper end of the burette to start to titrate into the polishing solution, simultaneously measuring the polishing solution by using an acidimeter, and continuing to titrate after the reading is stable until the pH value is displayed to 10.76, which is marked as polishing solution S3;
polishing: the polishing solution S3 was added to a Universal-300Plus type polisher manufactured by Waschanheinaceae at a working pressure of Z1: 4.76Psi, Z2: 2.01Psi, Z3: 1.82Psi, Z4: 1.92Psi, Z5: 1.63 Psi; the rotating speed of the throwing head is 98 r/min; the rotating speed of the polishing disc is 105 r/min; polishing was carried out under a polishing liquid flow rate of 250 ml/min.
Example 4
A control method for the selective ratio of the dielectric to the copper rate in the CMP process comprises the following steps:
preparing 10kg of polishing solution: taking 10% by mass of silica sol with the particle size of 100nm, and adding deionized water to dilute the silica sol to 5kg to obtain a silica sol solution; mixing 2 mass percent of complexing agent, 1 mass percent of bactericide and 1.6 mass percent of surfactant, adding deionized water to dilute the mixture to 5kg, adding the silica sol solution, and uniformly stirring to obtain polishing solution for later use;
the complexing agent is a mixture of FA/O1 chelating agent, FA/O2 chelating agent, FA/O3 chelating agent, FA/O4 chelating agent and FA/O5 chelating agent;
the bactericide is a mixture of methylisothiazolinone, kason, potassium sorbate, benzoic acid, 5-chloro-2-methyl-4-isothiazolin-3-one and 1-2 benzisothiazolin-3-one, wherein the kason is a mixture of 2-methyl-4-isothiazolin-3-one, 2-methyl-5-chloro-4-isothiazolin-3-one and an inorganic salt stabilizer, and the mass ratio of the 2-methyl-4-isothiazolin-3-one to the 2-methyl-5-chloro-4-isothiazolin-3-one is 3: 1;
the surfactant is prepared by mixing FA/O surfactant, dodecyl dimethyl amine oxide, sodium dodecyl sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and heterogeneous fatty alcohol-polyoxyethylene ether;
preparing a pH value regulator: mixing hydrochloric acid, an FA/O1 chelating agent, an FA/O2 chelating agent, an FA/O3 chelating agent, an FA/O4 chelating agent and an FA/O5 chelating agent for later use;
adjusting the pH value: taking a pH value regulator by using an acid burette or a basic burette, holding the non-scale part at the upper end of the burette to start to titrate into the polishing solution, simultaneously measuring the polishing solution by using an acidimeter, and continuing to titrate after the reading is stable until the pH value is 11.07, which is recorded as polishing solution S4;
polishing: the polishing solution S4 was added to a Universal-300Plus type polisher manufactured by Waschanheinaceae at a working pressure of Z1: 4.76Psi, Z2: 2.01Psi, Z3: 1.82Psi, Z4: 1.92Psi, Z5: 1.63 Psi; the rotating speed of the throwing head is 98 r/min; the rotating speed of the polishing disc is 105 r/min; polishing was carried out under a polishing liquid flow rate of 250 ml/min.
Test examples
By the control method of the embodiments 1 to 4 of the present invention, the pH of the polishing solution was adjusted by using the pH adjusting agent to obtain polishing solutions S1, S2, S3, and S4 having pH values of 9.98, 10.35, 10.76, and 11.07, respectively, and then a 300mm pattern piece was polished, and after cleaning, the removal rates of the medium (Ox) and copper were measured by using a medium film thickness tester and a four-probe resistivity meter, respectively. The results are shown in table 1 and fig. 1.
TABLE 1
As can be seen from table 1 and fig. 1, as the pH of the polishing liquid increases, the removal rate of Cu gradually increases and the removal rate of the medium gradually decreases, and therefore, the removal rate ratio Ox RR/Cu RR also gradually decreases, indicating that the removal rate ratio of medium to copper can be effectively controlled by adjusting the pH of the polishing liquid.
In summary, the present invention provides a method for controlling the rate selectivity of the dielectric to copper in the CMP process, wherein a pH adjuster is selected to adjust the pH of the polishing solution, so as to control the removal rate ratios of the dielectric and copper of different materials, and the rate selectivity is controllable and adjustable. The pH value of the polishing solution determines the existence environment of the polishing solution and components inside the polishing solution, and the existence form of the components in the polishing solution in the planarization process, the stability of the alkaline polishing solution mainly depends on the stability of silica sol in the polishing solution, the pH value is the most main factor influencing the agglomeration of the silica sol, and when the pH value is 7-9, the silica sol is easy to agglomerate; when the pH value is 9-11.5, the colloidal particle stability of the silica sol reaches the highest peak, and meanwhile, the dispersion characteristic is also the best; when the pH is more than 11.5, the spherical abrasive particles start to dissolve, and thus it is important to control the pH of the polishing liquid to stabilize the polishing rate. The method has the advantages that for different products and different thicknesses of copper and media of different interconnection layers, different removal rate ratios of the media and the copper are inconvenient to realize by reconfiguring the formula of the polishing solution every time, the pH value of the polishing solution is directly adjusted, the polishing solution does not need to be replaced again, and different removal rate ratios of the media and the copper can be achieved under different pH values so as to adapt to the rate selection ratio of the media and the copper required by different materials in the CMP process and further realize high planarization of the surface of the graph.
In addition, the FA/O type chelating agent contained in the polishing solution is a polyhydroxy polyamino base macromolecular organic matter, the reaction with copper is slow under a static condition when the pH value is 9.0-11.5, and under the CMP condition, the energy provided by the system overcomes the reaction potential energy, so that the reaction is fast and accelerated, the FA/O type chelating agent can efficiently react with copper ions to generate a chelate, so that the high removal rate of copper is realized, the polishing rate is accelerated, and because the surface of a polishing sheet is different in height, the energy at the high position is higher than the energy at the low position, so that the difference of the high and low positions is caused, and the surface is flattened after polishing.
The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Claims (10)
1. A method for controlling the selectivity of the dielectric to copper rate in a CMP process, comprising the steps of:
adjusting the pH value of the polishing solution to 9.0-11.5 by adopting a pH value regulator; adding the polishing solution into a polishing machine to polish the graphic sheet to obtain a finished product;
wherein the polishing conditions are as follows: the working pressure is 1-5Psi, the rotation speed of the polishing head is 88-108r/min, the rotation speed of the polishing disc is 100-.
2. The method of claim 1, wherein the pH adjusting agent is one or more of sulfuric acid, nitric acid, hydrochloric acid, potassium hydroxide, FA/O1 chelating agent, FA/O2 chelating agent, FA/O3 chelating agent, FA/O4 chelating agent, and FA/O5 chelating agent.
3. The method of claim 1, wherein the adjusting step comprises: and (3) taking a pH value regulator by using an acid burette or a basic burette, holding the non-scale part at the upper end of the burette to start titration in the polishing solution, measuring the pH value of the polishing solution by using an acidimeter, and continuing the titration until the read number is stable until the specified pH value is displayed.
4. The method as claimed in claim 1, wherein the polishing liquid comprises the following components by mass percent: 3-10% of silica sol, 0.02-2% of complexing agent, 0.03-2% of bactericide, 0.0001-3% of surfactant and the balance of deionized water.
5. The method as claimed in claim 4, wherein the silica sol has a particle size of 30nm to 200 nm.
6. The method of claim 4, wherein the complexing agent is one or more of a type FA/O1 chelating agent, a type FA/O2 chelating agent, a type FA/O3 chelating agent, a type FA/O4 chelating agent, and a type FA/O5 chelating agent.
7. The method of claim 4, wherein the biocide is one or more of methylisothiazolinone, kason, potassium sorbate, benzoic acid, 5-chloro-2-methyl-4-isothiazolin-3-one, and 1-2 benzisothiazolin-3-one.
8. The method for controlling a rate selective ratio of a medium to copper in a CMP process of claim 7, wherein the cason is a mixture of 2-methyl-4-isothiazolin-3-one, 2-methyl-5-chloro-4-isothiazolin-3-one and an inorganic salt stabilizer, wherein a mass ratio of 2-methyl-4-isothiazolin-3-one to 2-methyl-5-chloro-4-isothiazolin-3-one is (3-4): 1.
9. The method as claimed in claim 4, wherein the surfactant is one or more selected from FA/O surfactant, dodecyl dimethyl amine oxide, sodium dodecyl sulfate, dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and isomeric fatty alcohol-polyoxyethylene ether.
10. The method as claimed in claim 4, wherein the method for preparing the polishing slurry comprises the following steps: taking silica sol, and adding deionized water for dilution to obtain a silica sol solution; and mixing the complexing agent, the bactericide and the surfactant, diluting with deionized water, adding a silica sol solution, and uniformly stirring to obtain the polishing solution.
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