Semiconductor wafer processing solution and method for producing the same

Abstract

Provided is a semiconductor wafer treatment solution containing at least one type of hypohalous acid ion and at least one type of anion selected from halic acid ions, halous acid ions, and halide ions. The content of the at least one type of anion of the abovementioned types of anion is 0.30 to 6.00 mol / L with respect to the treatment solution.

Description

[Technical Field]

[0001] The present invention relates to a semiconductor wafer treatment liquid, and more particularly to a semiconductor wafer treatment liquid that has a sufficient etching rate for metals used in wiring layers of semiconductor elements and is capable of suppressing metal surface roughening due to etching. [Background technology]

[0002] In semiconductor devices, wiring layers play an important role in transmitting electrical signals from transistors to the outside. In recent years, the design rules for semiconductor devices have become increasingly finer, leading to an increase in wiring resistance. As a result of this increase in wiring resistance, it has become apparent that the high-speed operation of semiconductor devices is being hindered, and countermeasures are therefore required. Therefore, wiring materials with higher electromigration resistance and reduced resistance than conventional wiring materials are desired.

[0003] Compared to conventional wiring materials such as aluminum and copper, ruthenium has a high resistance to electromigration and can reduce the resistance of wiring, which is why it is attracting attention as a wiring material, especially for semiconductor device design rules of 10 nm or less.In addition to being used as a wiring material, ruthenium can also prevent electromigration even when copper is used as the wiring material, so its use as a barrier metal for copper wiring is also being considered.

[0004] In the wiring formation process for semiconductor devices, even when ruthenium is selected as the wiring material, wiring is formed by dry etching or wet etching, as with conventional wiring materials. However, when dry etching ruthenium, precision etching is difficult because in-plane non-uniformity occurs due to the distribution of plasma, and the etching rate varies depending on the flux or energy of the reactive species and ions. In addition, there are issues such as etching being hindered by the strong adhesion of the reaction product RuO2 to the pattern wall surface. For these reasons, wet etching has attracted attention as a method for etching ruthenium more precisely.

[0005] As semiconductor device design rules become more refined, multilayer interconnects are being fabricated by stacking multiple interconnect layers in the interconnect formation process. However, achieving multilayer interconnects requires an etch-back process (recess process) to prevent yield loss due to leakage current caused by pattern misalignment. Since surface roughness caused by etching the metal that forms the interconnect layer increases contact resistance between the interconnect layers, etching that suppresses metal surface roughness is considered one of the most important aspects of the process. Naturally, from the perspective of throughput, the metal dissolution rate, i.e., the etching rate, is also important. Therefore, there is a need for semiconductor processing solutions that have sufficient metal etching rates and minimal surface roughness after etching.

[0006] Various liquids have been proposed as processing solutions used for wet etching metals such as ruthenium on semiconductor wafers. For example, Patent Document 1 proposes a method for etching a ruthenium film using a chemical solution with a pH of 12 or higher and a standard oxidation-reduction potential of 300 mV vs. SHE (standard hydrogen electrode) or higher, specifically a solution containing a halogen oxyacid salt such as hypochlorite, chlorite, or bromate. Patent Document 2 also proposes a cleaning method in which ruthenium is oxidized, dissolved, and removed using a removal solution containing cerium (IV) ammonium nitrate to which a strong acid such as nitric acid has been added.

[0007] Furthermore, Patent Document 3 proposes a treatment liquid for ruthenium-containing wafers that contains hypochlorite ions and a solvent and has a pH of more than 7 and less than 12.0 at 25°C as a treatment liquid used for etching metals on semiconductor wafers. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-161381 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-234373 [Patent Document 3] International Publication No. 2019 / 142788 [Patent Document 4] Japanese Patent Application Publication No. 2019-218436 Summary of the Invention [Problem to be solved by the invention]

[0009] The treatment solutions described in Patent Documents 1 to 3 all contain an oxidizing agent for ruthenium and remove ruthenium by oxidizing it. These treatment solutions are capable of removing ruthenium at a high etching rate and are particularly useful for removing metals such as ruthenium adhering to the edge (bevel) or back surface of a semiconductor wafer.

[0010] On the other hand, in the above-mentioned etch-back process, it is necessary to accurately control the etching rate of the surface to be treated. Specifically, it is necessary to control the surface roughness of the surface to be etched to a level of about 3 nm or less. However, none of the treatment solutions described in Patent Documents 1 to 3 above mentions the smoothness of the surface to be treated after etching. When the present inventors etched ruthenium using these treatment solutions, they found that although the etching rate was very high, it was difficult to control the surface roughness of the surface after etching, and there was room for improvement in terms of the smoothness of the surface after etching.

[0011] To address the above-mentioned problems, the present inventors focused on the ion species contained in a treatment solution containing hypochlorite ions in order to control surface roughness after etching. They discovered that by incorporating a small amount of chlorite ions into an oxidizing composition containing hypochlorite ions and quaternary alkylammonium ions, it is possible to control the etching rate to 20 Å / min or less, thereby improving the storage stability of hypochlorite ions, precisely controlling the etching rate, and suppressing surface roughness after etching (see Patent Document 4).

[0012] By using the treatment liquid described in Patent Document 4, it is possible to perform etching while suppressing surface roughness after etching, and this treatment liquid is a liquid suitable for an etch-back process. However, this treatment liquid has an extremely low etching rate, and there is still room for improvement in terms of suppressing surface roughness after etching while maintaining a high etching rate.

[0013] Therefore, an object of the present invention is to provide a semiconductor wafer treatment liquid that has a sufficient etching rate for metals used in wiring layers of semiconductor elements and is capable of suppressing metal surface roughening due to etching. [Means for solving the problem]

[0014] The present inventors have conducted extensive research to solve the above problems. First, they investigated additives capable of adjusting the etching rate of ruthenium in a treatment solution containing hypochlorite ions. As a result, they discovered that the etching rate of the treatment solution can be controlled by adding an anion species other than hypochlorite ions to the treatment solution. Then, they further investigated the anion species to be added to the treatment solution. As a result, they found that adding specific amounts of halate ions, haloid ions, and halide ions to the treatment solution maintains a sufficient etching rate for ruthenium and suppresses surface roughening due to etching, and that the same effect is also achieved for metals other than ruthenium, thereby completing the present invention.

[0015] That is, the present invention is configured as follows. Item 1: A processing liquid for semiconductor wafers, The treatment solution contains at least one hypohalite ion, and at least one anion species selected from a halate ion, a halite ion, and a halide ion; A processing solution for semiconductor wafers, wherein the content of at least one of the anion species is 0.30 mol / L or more and 6.00 mol / L or less relative to the processing solution. Item 2. The semiconductor wafer treating solution according to Item 1, wherein the anion species comprises two or more kinds of anion species. Item 3. The semiconductor wafer treatment solution according to Item 1 or 2, wherein the anion species contained in the treatment solution in an amount of 0.30 mol / L or more and 6.00 mol / L or less includes at least a halide ion. Item 4. The processing solution for semiconductor wafers according to any one of Items 1 to 3, wherein the content of the hypohalite ions in the processing solution is 0.0010 mol / L or more and 4.00 mol / L or less. Item 5. The semiconductor wafer treating liquid according to any one of Items 1 to 4, wherein the hypohalite ions include at least one selected from hypochlorite ions and hypobromite ions. Item 6. The semiconductor wafer treatment liquid according to Item 5, wherein the hypohalite ions include hypochlorite ions and hypobromite ions. Item 7. The treatment solution for semiconductor wafers according to any one of Items 1 to 6, wherein the hypohalite ions include at least hypobromite ions, and the content of the hypobromite ions in the treatment solution is 0.0010 mol / L or more and 0.20 mol / L or less. Item 8. The treatment liquid for semiconductor wafers according to any one of Items 1 to 7, further comprising an onium ion. Item 9. The treatment liquid for semiconductor wafers according to any one of Items 1 to 8, wherein the treatment liquid has a pH of 7 or more and 14 or less. Item 10. The semiconductor wafer treatment solution according to any one of Items 1 to 9, wherein the semiconductor wafer contains at least one metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W. Item 11. A step of preparing a first solution containing at least one anion species selected from halide ions, halite ions, and halide ions; preparing a second solution containing hypohalite ions; and mixing the first solution and the second solution; A method for producing a processing liquid for semiconductor wafers. Item 12. The method for producing a processing solution for semiconductor wafers according to Item 11, wherein the oxidizing power of hypohalite ions contained in the second solution is higher than the oxidizing power of anion species contained in the first solution. Item 13. The method for producing a treatment solution for semiconductor wafers according to Item 11 or 12, wherein at least one of the anion species contained in the first solution is a bromide ion, and the hypohalite ion contained in the second solution is a hypochlorite ion. Item 14. The method for producing a processing liquid for semiconductor wafers according to any one of Items 11 to 13, wherein at least one solution selected from the first solution and the second solution contains an onium ion. Item 15. The method for producing a processing liquid for semiconductor wafers according to Item 14, wherein the first solution and the second solution each contain onium ions. Item 16: A kit for preparing a processing solution for semiconductor wafers, comprising at least a first solution containing at least one anion species selected from halide ions, haloid ions, and halide ions, and a second solution containing hypohalite ions. Item 17. The kit according to Item 16, wherein the oxidizing power of the hypohalite ions contained in the second solution is higher than the oxidizing power of the anion species contained in the first solution. Item 18. The kit according to Item 16 or 17, wherein at least one of the anion species contained in the first solution is a bromide ion, and the hypohalite ion contained in the second solution is a hypochlorite ion. [Effects of the Invention]

[0016] The semiconductor wafer treatment solution of the present invention can maintain a sufficient etching rate for metals, particularly ruthenium, used in the wiring layers of semiconductor elements, suppress surface roughening due to etching, and further improve the stability of the treatment solution. DETAILED DESCRIPTION OF THE INVENTION

[0017] (Semiconductor wafer processing liquid) The semiconductor wafer treatment solution of the present invention (hereinafter also referred to simply as "treatment solution") contains at least one hypohalite ion and at least one anion species selected from halide ions, halite ions, and halide ions, and is characterized in that the content of the at least one anion species is 0.30 mol / L to 6.00 mol / L. The semiconductor wafer treatment solution of the present invention is capable of maintaining a sufficient etching rate for ruthenium and the like and suppressing surface roughness caused by etching. Unless otherwise specified, in this specification, the notation "A to B" for numerical values ​​A and B means "A or more, B or less." In such notation, when a unit is added only to numerical value B, the unit is also applied to numerical value A. Furthermore, although a plurality of embodiments are described in this specification, the conditions in each embodiment can be applied to each other to the extent that they are applicable.

[0018] The present inventors speculate that the reason why the semiconductor wafer treatment solution of the present invention maintains a sufficient etching rate for ruthenium and suppresses surface roughening due to etching is as follows: That is, when a treatment solution containing hypohalite ions is used as an etching solution for ruthenium, for example, when hypochlorite ions are used, ruthenium is oxidized and removed by the following reaction (Equation 1). 2Ru+7ClO - +H2O → 2RuO4 - +7Cl - +2H + (Formula 1)

[0019] The treatment solution of the present invention is characterized by containing, in addition to hypohalite ions, a specific amount of anion species selected from halide ions, haloid ions, and halide ions. It is believed that these anion species are present to a certain extent evenly on the ruthenium surface in the treatment solution, and therefore it is believed that it is possible to control to some extent the etching rate of ruthenium by hypohalite ions. It is believed that by reducing the etching rate of ruthenium, it is possible to suppress surface roughening due to etching.

[0020] Conventionally, it has been thought that it is difficult to dissolve ruthenium, and therefore it is presumed that the etching rate is increased by reducing the content of other anion species in ruthenium etching solutions as much as possible, thereby promoting the above-mentioned reaction with hypohalite ions on the ruthenium surface.

[0021] In addition to being consumed in the above reaction, the concentration of hypohalite ions in the treatment solution decreases due to the following disproportionation reaction (Equation 2). 2ClO - → ClO2 - +Cl- (Formula 2)

[0022] The treatment solution of the present invention contains a specific amount of anion species selected from halide ions, hypohalite ions, and halide ions, and it is presumed that this inhibits the reaction between the hypohalite ions, thereby suppressing a decrease in the content of hypohalite ions, and therefore it is presumed that a high etching rate and good stability can be maintained. That is, it is believed that the disproportionation reaction rate of hypochlorite ions or hypobromite ions can be reduced by previously adding chloride ions or bromide ions, which are decomposition products of the disproportionation reaction, to the treatment solution of the present invention. This reduces the change in concentration of hypochlorite ions or hypobromite ions, which are chemical species that etch ruthenium, and not only stabilizes the etching rate of ruthenium but also improves the storage stability of the treatment solution and extends its lifespan.

[0023] Therefore, by using the semiconductor wafer treatment solution of the present invention, not only can the wafer treatment efficiency per unit time be improved, but also it can be suitably used as a treatment solution for, for example, a metal etch-back process in a semiconductor manufacturing process, which requires precise etching control for wiring materials.Furthermore, since it has the same effect on metals other than ruthenium, it can be used as a treatment solution for metals contained in semiconductor wafers, not limited to ruthenium.

[0024] Each component of the semiconductor wafer treatment solution of the present invention will be described in detail below.

[0025] (hypohalite ion) The hypohalite ions contained in the treatment solution of the present invention act as an oxidizing agent for metals such as ruthenium, forming oxides of the metal or converting the metal into ionic species, thereby etching the metal layer.

[0026] The hypohalite ions contained in the treatment solution of the present invention are specifically hypochlorite ions (ClO -), hypobromite ion (BrO - ), or hypoiodite ion (IO - ) are included. In particular, it is preferable that the hypohalite ion contains at least one selected from hypochlorite ions and hypobromite ions in terms of the etching rate for metals and stability during storage or use. When etching a semiconductor wafer containing ruthenium as the metal, hypobromite ions are particularly preferable in terms of the etching rate for ruthenium and the ability to suppress the generation of toxic ruthenium gas (RuO4), which is likely to be generated by the oxidation of ruthenium. The above hypohalite ions may be used alone, or two or more types of hypohalite ions may be used. For example, the hypohalite ions contained in the treatment solution of the present invention may contain two types of hypochlorite ions, namely hypobromite ions and hypobromite ions.

[0027] The hypohalite ions used in the present invention can be generated by dissolving hypohalous acid or a hypohalite salt in the treatment solution. Examples of hypohalite salts include alkali metal salts, alkaline earth metal salts, and organic salts. Specific examples of alkali metal salts include sodium hypochlorite, sodium hypobromite, and sodium hypoiodite. Examples of organic salts include organic salts containing onium ions, such as quaternary alkylammonium salts, such as tetramethylammonium hypochlorite, tetramethylammonium hypobromite, and tetramethylammonium hypoiodite. Among these, it is preferable to use organic salts containing onium ions, such as quaternary alkylammonium salts, that do not contain metals that can reduce yields in semiconductor formation processes. Tetramethylammonium hypochlorite or tetramethylammonium hypobromite is particularly preferable.

[0028] The hypohalite salt may be an industrially available salt or may be prepared by a known method. For example, a quaternary alkylammonium salt can be prepared by preparing an aqueous solution of tetramethylammonium hydroxide and blowing chlorine, bromine, or the like into it. Alternatively, a solution containing a quaternary alkylammonium hypohalite salt can be prepared by contacting a tetramethylammonium hydroxide solution with a cation exchange ion exchange resin to convert the cations in the ion exchange resin into tetramethylammonium ions, and then passing a sodium hypohalite solution through the resin to exchange the sodium ions for the tetramethylammonium ions.

[0029] (Concentration of hypohalite ions) The concentration of hypohalite ions in the treatment solution of the present invention is not particularly limited as long as it does not deviate from the objectives of the present invention, and may be appropriately set depending on the type of metal to be etched and the etching site. From the viewpoints of the etching rate for the metal and stability during storage and use, the concentration is preferably in the range of 0.0010 mol / L to 4.00 mol / L inclusive, more preferably 0.0050 mol / L to 2.00 mol / L inclusive, and particularly preferably 0.010 mol / L to 0.80 mol / L inclusive. When two or more types of hypohalite ions are contained as hypohalite ions, the total concentration of the multiple hypohalite ions should be within the above range. In this specification, "concentration" is also referred to as "content."

[0030] For example, when hypochlorite ions are contained as hypohalite ions, the concentration range of the hypochlorite ions is more preferably 0.020 mol / L or more and 3.00 mol / L or less, even more preferably 0.060 mol / L or more and 2.00 mol / L or less, still more preferably 0.10 mol / L or more and 1.20 mol / L or less, and particularly preferably 0.10 mol / L or more and 0.80 mol / L or less. Furthermore, when hypobromite ions are included as hypohalite ions, the concentration range of the hypobromite ions is more preferably 0.0010 mol / L or more and 0.20 mol / L or less. If the concentration is less than 0.0010 mol / L, the metal etching rate tends to be slow. On the other hand, if the concentration exceeds 0.20 mol / L, the hypobromite ions are more likely to decompose, making it difficult to stabilize the metal etching rate. Therefore, in order to stably etch metals at a sufficient rate, the concentration of the hypobromite ions is more preferably 0.0010 mol / L or more and 0.20 mol / L or less, even more preferably 0.0050 mol / L or more and 0.20 mol / L or less, and most preferably 0.010 mol / L or more and 0.10 mol / L or less.

[0031] When hypobromite ions are used as hypohalite ions, it is preferable to further include hypochlorite ions. When hypobromite ions are used, bromide ions are generated by reaction with a metal such as ruthenium. If hypochlorite ions are contained at this time, the oxidation-reduction potential of hypochlorite ions-chloride ions (0.89 V (at 25°C, pH 14, vs. standard hydrogen electrode)) is higher than the oxidation-reduction potential of hypobromite ions-bromide ions (0.76 V (same as above)), so the generated bromide ions are oxidized to generate hypobromite ions. Therefore, when hypobromite ions are used, it is preferable to further include hypochlorite ions, as this makes it possible to maintain the hypobromite ions at a predetermined concentration and facilitates stable control of the etching rate.

[0032] When hypochlorite ions are further contained in addition to the hypobromite ions, from the viewpoint of stably controlling the etching rate, the ratio of the content of hypobromite ions to the content of hypochlorite ions, i.e., hypobromite ions (mol) / hypochlorite ions (mol), is preferably in the range of 0.001 to 100, more preferably in the range of 0.1 to 50, and particularly preferably in the range of 0.5 to 10.

[0033] The concentration of hypohalite ions in the treatment solution can be calculated when the treatment solution is produced, or can be confirmed using a known method. Specifically, as a measurement method, the absorption due to hypohalite ions is confirmed by ultraviolet-visible absorptiometry, and the concentration of hypohalite ions can be determined from the intensity of the absorption peak and a calibration curve prepared using a hypohalite ion solution of known concentration.

[0034] (anionic species) The treatment solution of the present invention contains at least one anion species selected from halide ions, haloid ions, and halide ions. It is presumed that these anion species interact with the metal to suppress surface roughness. Specific examples of the anion species include ClO3 - , BrO3 - , or IO3 - Halide ions such as ClO2 - , BrO2 - , or IO2 - Haloid ions such as Cl - , Br - , or I - The treatment solution may contain one or more of these anion species. When two or more anion species are contained, it is possible to use either a case where ions having the same oxidation number of halogen atoms are contained, such as two types of halide ions, or a case where ions having different oxidation numbers of halogen atoms are contained, such as one type of halite ion and one type of halide ion. In this specification, unless otherwise specified, the term "anion species" refers to at least one anion species selected from halate ions, haloid ions, and halide ions.

[0035] Among these, halide ions are preferred as the anion species, particularly as the anion species contained within the concentration range described below, in terms of solubility in the treatment solution, ease of availability, storage stability, and cost. For example, tetramethylammonium chloride, which generates chloride ions, a type of halide ion, upon dissolution, has extremely high solubility (up to 70 wt % at 25°C) and little temperature dependence of solubility, making it less likely to form precipitates that could cause a decrease in etching rate or increase surface roughness. It is also more preferred that the treatment solution contain two or more anion species. When two or more anion species are contained in the treatment solution, it is particularly preferred that the treatment solution contain halide ions and an anion species with a halogen atom whose oxidation number differs from that of the halide ions, in order to effectively suppress roughness of the metal surface.

[0036] The anion species used in the present invention can be generated by dissolving an acid or salt containing the anion species in the treatment solution. Examples of acids containing anion species include halogen acids such as chloric acid, bromic acid, or iodic acid; halogenous acids such as chlorous acid, bromous acid, or iodous acid; and hydrogen halides such as hydrogen chloride, hydrogen bromide, or hydrogen iodide. Examples of salts containing anion species include alkali metal salts, alkaline earth metal salts, and organic salts. Specific examples of alkali metal salts include potassium chloride, sodium chlorite, potassium bromide, sodium bromite, potassium iodide, and sodium iodite. Examples of organic salts include organic salts containing onium ions, such as quaternary alkylammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and tetramethylammonium iodide. The hydrogen halides can also be generated by dissolving halogen gases such as chlorine gas, bromine gas, or iodine gas in water. Among these, it is preferable to use an acid or organic salt containing an anion species because it does not contain metals that cause a decrease in yield in semiconductor manufacturing, and furthermore, in consideration of ease of industrial availability and ease of handling, an organic salt containing an onium ion such as a quaternary alkylammonium salt is more preferable. Among organic salts, those that can be particularly preferably used in terms of stability, purity, and cost include tetramethylammonium chloride, bromide, or iodide, tetraethylammonium chloride, bromide, or iodide, and tetrapropylammonium chloride, bromide, or iodide.

[0037] The acid or salt containing the anion species used to generate the anion species in the treatment solution may be an industrially available salt, or may be prepared by a known method. For example, a quaternary alkylammonium salt containing the anion species can be prepared by preparing an aqueous solution of tetramethylammonium hydroxide and blowing in chlorine, bromine, or the like. Alternatively, a tetramethylammonium hydroxide solution can be brought into contact with a cation-exchange ion-exchange resin to convert the cations in the ion-exchange resin into tetramethylammonium ions, and then the salt can be prepared.Basic A solution containing a quaternary alkylammonium salt of the anion species can also be prepared by a method of exchanging ions by passing a halogen acid such as acetic acid, bromic acid, or iodic acid through the solution.

[0038] (anion species concentration) In the treatment solution of the present invention, the concentration of at least one of the anion species is 0.30 mol / L or more and 6.00 mol / L or less. When the treatment solution of the present invention contains only one anion species, the concentration of the anion species must be 0.30 mol / L or more and 6.00 mol / L or less. When the treatment solution contains two or more anion species, the concentration of at least one of the anion species must be 0.30 mol / L or more and 6.00 mol / L or less. By containing the anion species in the treatment solution within the above range, it is possible to maintain a sufficient etching rate for metals such as ruthenium and to suppress surface roughness due to etching. From the viewpoint of achieving both a sufficient etching rate and smoothness, the concentration of the anion species is more preferably 0.30 mol / L or more and 3.00 mol / L or less, and most preferably 0.30 mol / L or more and 1.00 mol / L or less. The above range may also be applied to the total concentration of anion species in the treatment liquid of the present invention.

[0039] When two or more of the anion species are contained in the treatment solution, from the viewpoint of achieving both a sufficient etching rate and smoothness, the anion species contained at a concentration of 0.30 mol / L or more and 6.00 mol / L or less is preferably a halide ion. Furthermore, when two or more of the anion species are contained, the concentrations of the anion species other than the anion species within the above concentration range are not particularly limited and may be appropriately set depending on the type of metal species to be etched and the etching site. The concentrations of the other anion species may also be 0.30 mol / L or more and 6.00 mol / L or less. If the concentration of the anion species is too high, the etching rate tends to decrease, and if it is too low, the effect of suppressing surface roughness tends to decrease. Therefore, when two or more anion species are contained, the total concentration of the anion species is preferably 6.00 mol / L or less, more preferably 3.00 mol / L or less, and most preferably 1.00 mol / L or less.

[0040] The ratio of the concentration (mol / L) of at least one anion species to the concentration (mol / L) of the hypohalite ions in the treatment solution (anion species concentration / hypohalite ion concentration) is not particularly limited, but from the viewpoint of effectively suppressing roughening of the metal surface, it is usually 2 or more, preferably 4 or more, more preferably 6 or more, and even more preferably 8 or more, and is usually 500 or less, preferably 200 or less, more preferably 50 or less, and even more preferably 10 or less, and furthermore, it is usually 2 or more to 500 or less, preferably 4 or more to 200 or less, more preferably 6 or more to 50 or less, and even more preferably 8 or more to 10 or less.

[0041] The concentration of anionic species in the treated solution can be measured using ion chromatography, which allows identification and quantification of anionic species by appropriately selecting the type of column and conditions.

[0042] (onium ion) The treatment solution of the present invention preferably further contains onium ions. By including onium ions in addition to the above-described anionic species, roughness of the metal surface can be further suppressed. The present inventors speculate that the mechanism by which surface roughness is suppressed by including onium ions is that the onium ions interact with the anionic species or the metal surface, enabling uniform etching of the metal.

[0043] Specific examples of onium ions that can be used in the treatment solution of the present invention include ammonium ions (NH + ), phosphonium ion (PH4 + ), or sulfonium ion (SH3 + The hydrogen atoms of these onium ions may be independently substituted. Specific examples of the substituent include alkyl groups having 1 to 25 carbon atoms; 3 Examples of the substituent include an allyl group having from 1 to 25 carbon atoms, an aralkyl group having from 7 to 11 carbon atoms, and an aryl group having from 6 to 10 carbon atoms. In the above substituents, the aryl group in the aralkyl group and the hydrogen atom in the aryl group may be substituted, and examples of such substituents include a fluorine atom, a chlorine atom, an alkyl group having from 1 to 15 carbon atoms, an alkenyl group having from 2 to 10 carbon atoms, an alkoxy group having from 1 to 9 carbon atoms, and an alkenyloxy group having from 2 to 9 carbon atoms.

[0044] From the viewpoint of achieving a high effect of suppressing roughness of the metal surface, the onium ion is preferably one in which all of the hydrogen atoms are independently substituted with an alkyl group having 1 to 25 carbon atoms, more preferably with an alkyl group having 2 to 10 carbon atoms, and most preferably with an alkyl group having 3 to 6 carbon atoms. Specific examples of such onium ions include tetrapropylammonium ion and tetrabutylammonium ion.

[0045] Two of the above onium ions may be bonded together via an alkylene group. The number of carbon atoms in the alkylene group bonding the two onium ions is preferably 2 to 10. Specific examples of such onium ions include a hexamethonium ion and a decamethonium ion.

[0046] Furthermore, the onium ion may have an alicyclic structure or a heterocyclic structure in which two hydrogen atoms are bonded by an alkyl group or an alkylene group. Specific examples of such onium ions include piperidinium ions, imidazolium ions, pyrrolidinium ions, oxazolium ions, and pyridinium ions. These ring structures may also have a substituent. Specific examples of such substituents include chlorine, bromine, fluorine, iodine, alkyl groups having 1 to 15 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, alkoxy groups having 1 to 9 carbon atoms, and alkenyloxy groups having 2 to 9 carbon atoms. Specific examples of onium ions having the above ring structure include 1,1-dimethylpiperidinium ions, 1-butyl-2,3-dimethylimidazolium ions, 1-butyl-1-methylpyrrolidinium ions, and 5-azoniaspiro[4,4]nonane ions.

[0047] Furthermore, two of the above onium ions having a ring structure may be bonded via an alkylene group. The alkylene group bonding the two onium ions preferably has 2 or more and 10 or less carbon atoms. Specific examples of such onium ions include 3,3'-methylenebis(1-tert-butyl-3-imidazolium) ion and 3,3'-methylenebis(1-(2,6-diisopropylphenyl)-3-imidazolium) ion.

[0048] The concentration of the onium ions when incorporated into the treatment solution of the present invention is not particularly limited and may be appropriately determined taking into account the type of metal to be treated with the treatment solution. A too high onium ion concentration tends to decrease the etching rate and cause uneven etching of the metal surface. On the other hand, a too low onium ion concentration not only tends to reduce the effect of suppressing surface roughness, but also tends to reduce the amount of metal that can be treated, thereby reducing the number of times the treatment solution can be reused. Therefore, the onium ion concentration is typically 0.000010 mol / L or more and 7.00 mol / L or less, preferably 0.000010 mol / L or more and 6.00 mol / L or less, more preferably 0.000010 mol / L or more and 3.00 mol / L or less, even more preferably 0.0010 mol / L or more and 2.00 mol / L or less, and particularly preferably 0.010 mol / L or more and 1.00 mol / L or less. An example of a method for adding onium ions to the treatment solution of the present invention is to generate onium ions by dissolving an onium salt composed of an onium ion and an anion in the treatment solution of the present invention. When onium ions are included as counterions of the hypohalite ions and / or anionic species, the concentration of the onium ions can be determined taking into account the content of these onium ions. That is, when hypohalite ions and / or anionic species onium salts are used in preparing the treatment solution of the present invention, the concentration of the onium salts to be added and the total concentration of the onium ions to be added can be adjusted to fall within the above-mentioned range. When hypohalite ions and / or anionic species onium ions are not used in preparing the treatment solution of the present invention, a compound containing the onium ions can be added so that the concentration of the onium ions to be added falls within the above-mentioned range. When onium ions are added, only one type may be added, or two or more types may be added in combination. Two or more types of onium ions may also be included.

[0049] (solvent) In the treatment liquid of the present invention, the remainder other than the hypohalite ions, the anion species, and other additives described in detail below is solvent, and after preparing each component, the remainder is adjusted with solvent so that the total is 100% by weight.

[0050] Water is most preferably used as the solvent. The water contained in the treatment solution of the present invention is preferably water from which metal ions, organic impurities, particles, etc. have been removed by distillation, ion exchange, filtration, various adsorption treatments, etc., and pure water or ultrapure water is particularly preferred. Alternatively, an organic solvent may be used as long as the hypohalite ions are stable in the solvent, such as acetonitrile or sulfolane.

[0051] Furthermore, water and an organic solvent may be used in combination as the solvent. By using water and an organic solvent in combination, oxidation of metals such as Ru proceeds relatively slowly, thereby suppressing oxidation of wiring and the like in the circuit formation portion. When water and an organic solvent are used in combination, the weight ratio of water to organic solvent (water / organic solvent) may be about 60 / 40 or more and 99.9 / 0.1 or less. The content of the solvent in the treatment liquid is not particularly limited, but from the viewpoint of being able to sufficiently dissolve the above-mentioned components, it is usually 30% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 94% by weight or more, and is usually 99% by weight or less, preferably 98% by weight or less, and more preferably 97% by weight or less.

[0052] (metal concentration) The treatment solution of the present invention may contain metals (or metal ions; hereinafter, metal ions are also referred to as metals) due to the addition of anionic species or onium ions or due to the manufacturing process of the treatment solution. Specific examples of metals include lithium, sodium, potassium, aluminum, magnesium, calcium, chromium, manganese, iron, nickel, cobalt, copper, silver, cadmium, barium, zinc, and lead, or their ions. However, because these metals can affect the stability of the alkylammonium salt, it is preferable that their presence be small. While the reason for this is unclear, it is thought that the metal acts as a catalyst to promote the decomposition reaction of the alkyl group in alkali. On the other hand, while a small metal content in the treatment solution is preferable, the presence of a small amount of metal makes it possible to maintain the flatness of the metal surface after etching (prevent surface roughness). Therefore, the metal content of the treatment solution is preferably 0.01 ppt to 1 ppb, more preferably 1 ppt to 1 ppb, even more preferably 1 ppt to 500 ppt, and most preferably 10 ppt to 200 ppt, of any one metal selected from lithium, sodium, potassium, aluminum, magnesium, calcium, chromium, manganese, iron, nickel, cobalt, copper, silver, cadmium, barium, zinc, or lead by mass. Furthermore, if these metals remain on semiconductor wafers, they can adversely affect the semiconductor wafers (e.g., reducing semiconductor wafer yields). The metal content in the treatment solution can be measured using an inductively coupled plasma mass spectrometer (e.g., ICP-MS, Agilent 8900, manufactured by Agilent Technologies) as described in the Examples below. If the metal content exceeds 1 ppb, it is possible to reduce the metal content to 1 ppb or less by filtration, distillation, ion exchange, or other methods.

[0053] (Other additives) The processing solution of the present invention may contain additives conventionally used in semiconductor processing solutions, as desired, within the scope of the present invention, such as acids, metal corrosion inhibitors, fluorine compounds, oxidizing agents, reducing agents, chelating agents, surfactants, pH adjusters, and antifoaming agents.

[0054] (pH of semiconductor wafer processing solution) In the semiconductor wafer treatment solution of the present invention, in order to treat metals smoothly and at a sufficient etching rate while suppressing decomposition of the treatment solution during storage and use, the pH of the treatment solution is preferably 7 or more and 14 or less. If the pH is less than 7, the decomposition of the hypohalite ion, which serves as an oxidizing agent, progresses, and the etching rate tends to be unstable. If the pH exceeds 14, metal dissolution tends to be difficult, making it difficult to obtain a sufficient etching rate. From the viewpoint of the stability of the treatment solution and the etching rate, when the hypohalite ion is hypochlorite ion, the pH of the treatment solution is more preferably 7 or more and 13 or less, more preferably 8 or more and 12 or less, and most preferably 8.5 or more and 11 or less. When the hypohalite ion is hypobromite ion, for the same reasons as above, the pH of the treatment solution is preferably 7 or more and 14 or less, more preferably 8 or more and 14 or less, and most preferably 9 or more and less than 13. Furthermore, when the hypohalite ions contain both hypobromite ions and hypochlorite ions, the pH of the treatment solution is preferably 7 or more and 14 or less, more preferably 8 or more and 14 or less, and most preferably 9 or more and 13 or less, for the same reasons as above.

[0055] To adjust the pH of the treatment solution, an acid or alkali can be added to the treatment solution. The acid may be either an inorganic acid or an organic acid, such as hydrofluoric acid, hydrochloric acid, hydrobromic acid, nitric acid, acetic acid, sulfuric acid, peroxodisulfuric acid, or formic acid. Other commonly used acids commonly used in semiconductor treatment solutions can also be used without limitation. Organic alkalis are preferred because they do not contain metal ions that can reduce yields in semiconductor manufacturing. Among organic alkalis, tetraalkylammonium hydroxides are preferred because they are readily available industrially and can coexist stably with the oxidizing agent contained in the treatment solution. Examples of such tetraalkylammonium hydroxides include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and choline. Among these, tetramethylammonium hydroxide is more preferred because it contains a large number of hydroxide ions per unit weight and is readily available as a high-purity product.

[0056] (Oxidation-reduction potential of semiconductor wafer processing solution) In the semiconductor wafer treatment liquid of the present invention, the oxidation-reduction potential of the treatment liquid (at 25°C, pH 14, vs. standard hydrogen electrode) is not particularly limited, but is preferably 500 mV or more and 1500 mV or less, more preferably 550 mV or more and 1500 mV or less, and even more preferably 650 mV or more and 1500 mV or less. If the oxidation-reduction potential is less than 500 mV, the oxidizing power tends to be low and the etching rate tends to be low. On the other hand, if it exceeds 1500 mV, although the oxidizing power is high, decomposition of hypohalite ions tends to occur, making the treatment liquid unstable.

[0057] The oxidation-reduction potential of the treatment solution can be easily controlled by appropriately adjusting the type and / or concentration of the hypohalite ions, halogen ions, halogenous ions, or halide ions contained in the treatment solution, the type and / or concentration of the other additives described above, the pH of the treatment solution, the temperature of the treatment solution, etc. The treatment solution for semiconductor wafers of the present invention, which has an oxidation-reduction potential adjusted in this manner within the above range, can be suitably used as a treatment solution for metals contained in semiconductor wafers.

[0058] (Method of manufacturing a processing solution for semiconductor wafers) The method for producing the semiconductor wafer treatment solution of the present invention is not particularly limited. Specifically, the treatment solution of the present invention may be prepared by adding the hypohalite ions and the compound that generates the anion species to a solvent such as water to a desired concentration, and then adding additives as needed and adjusting the pH to a desired level. Alternatively, the treatment solution of the present invention may be prepared by preparing multiple solutions (hereinafter also referred to as "preparation materials") in which each component is separately blended, and mixing these preparation materials immediately before processing semiconductor wafers. When multiple preparation materials are prepared and mixed to form the treatment solution of the present invention, the components contained in the preparation materials may be those that react with the components in the preparation materials after mixing to generate either the hypohalite ions and / or the anion species. The pH and composition of the treatment solution of the present invention may change over time, resulting in changes in etching performance, such as etching rate. Therefore, from the perspective of suppressing deterioration in etching performance due to changes over time, it is preferable to prepare multiple preparation materials and mix these preparation materials immediately before processing semiconductor wafers to form the treatment solution of the present invention. When preparing multiple preparation materials, the number of preparation materials may be prepared for each component, but taking into consideration operability during mixing, it is preferable to prepare two types of preparation materials.

[0059] Hereinafter, a method for producing a semiconductor wafer processing solution according to one embodiment of the present invention will be described in detail, specifically, a production method including a step of preparing a first solution (preparation material 1) (first solution preparation step), a step of preparing a second solution (preparation material 2) (second solution preparation step), and a step of mixing these preparation materials (preferably immediately before processing the semiconductor wafer) (mixing step). The above-mentioned semiconductor wafer processing solution may be produced by this method. In addition, this production method includes the step of preparing the first solution. Made Step 2: Preparation of the second solution Made The method may include steps other than the step of mixing.

[0060] (Materials for preparation) The advantage of using two preparation materials, the first solution and the second solution, is, for example, improved stability of etching performance when using relatively unstable hypohalite ions as a treatment solution. That is, when the treatment solution is a single solution, there is a time lag between the production of hypohalite ions and the processing of semiconductor wafers at a semiconductor manufacturing factory, and the decomposition of hypohalite ions can change etching performance, such as etching rate. On the other hand, when the treatment solution is prepared as two preparation materials, the first solution and the second solution, and hypohalite ions are generated by mixing Preparation Material 1 and Preparation Material 2, a treatment solution containing hypohalite ions is produced at the semiconductor manufacturing factory immediately before processing semiconductor wafers. This suppresses the decomposition of hypohalite ions and enables stable etching performance. In particular, when the treatment solution of the present invention is used in the etch-back process, microfabrication is required, and precise control of the etching rate and surface roughness is necessary. Therefore, the above-mentioned embodiment is preferred. Furthermore, the preparation material in this specification may be treated as the above-mentioned semiconductor wafer processing liquid, and in this case may be referred to as a semiconductor wafer processing liquid preparation material.

[0061] Therefore, when preparing the treatment liquid as two preparation materials, the first solution and the second solution, from the viewpoint of the storage stability of the preparation materials themselves and the ability to stably suppress metal surface roughness, it is preferable that the components in the two solutions that make up each preparation material be as follows. First solution: a solution containing at least one anion species selected from halide ions, halite ions, and halide ions Second solution: A solution containing hypohalite ions The preparation material may be in an embodiment containing only the preparation material 1 and the preparation material 2, but may also contain preparation materials other than these preparation materials.

[0062] Here, to generate hypohalite ions by mixing two preparation materials, the first solution and the second solution, the first solution may contain halide ions, and the second solution may contain hypohalite ions with a higher oxidizing power than the halide ions in the first solution. Examples of such hypohalite ions include hypochlorite ions for bromide ions, and hypochlorite ions and hypobromite ions for iodide ions. Specifically, for example, when producing a treatment solution of the present invention containing hypobromite ions as the hypohalite ions, the first solution may be a solution containing bromide ions, and the second solution may be a solution containing hypochlorite ions. The oxidation-reduction potential of hypochlorite ion-chloride ion (0.89 V (at 25°C, pH 14, vs. standard hydrogen electrode)) is higher than the oxidation-reduction potential of hypobromite ion-bromide ion (0.76 V (same as above)). Therefore, by mixing the first solution and the second solution, bromide ion is oxidized by hypochlorite ion, generating hypobromite ion, and a treatment liquid containing hypobromite ion can be produced.

[0063] (Method for preparing the first solution) In the present invention, the method for preparing the first solution is not particularly limited. Specifically, the first solution can be prepared by adding at least one anion species selected from halide ions, haloid ions, and halide ions to a solvent such as water. Other additives can also be added to the first solution as needed. When hypohalite ions are generated by mixing the two preparation materials for the first and second solutions, if bromide ions or iodide ions are contained in the first solution, the ions can be obtained, for example, by dissolving a salt or the like that generates the ions upon dissolution into the solution. Examples include metal salts such as sodium bromide and sodium iodide, organic salts such as tetraalkylammonium bromide and tetraalkylammonium iodide, halogen gases such as bromine gas and iodine gas, and hydrogen halides such as hydrogen bromide and hydrogen iodide. Among these, organic salts, halogen gases, and hydrogen halides are preferred because they do not contain metals that can reduce yields in semiconductor manufacturing. In view of ease of industrial availability and handling, organic salts are more preferred as raw materials for bromide ions or iodide ions. Among these organic salts, organic salts containing onium ions such as tetramethylammonium bromide or iodide, tetraethylammonium bromide or iodide, or tetrapropylammonium bromide or iodide are particularly suitable in terms of stability, purity, and cost.

[0064] The organic salt used in the present invention can be, for example, tetraalkylammonium bromide produced from tetraalkylammonium ions and bromide ions. The method for producing tetraalkylammonium bromide involves simply mixing an aqueous solution containing tetraalkylammonium hydroxide with an aqueous solution containing bromide ions, or a bromine-containing gas that generates bromide ions when dissolved in water, such as hydrogen bromide. Examples of tetraalkylammonium hydroxides used to produce tetraalkylammonium bromide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. Among these, tetramethylammonium hydroxide is preferred because it contains a large number of hydroxide ions per unit weight and is readily available as a high-purity product. Examples of bromide ion sources that generate bromide ions used to produce tetraalkylammonium bromide include hydrogen bromide, lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, and ammonium bromide. Hydrogen bromide is preferred because it is substantially metal-free, industrially readily available, and readily available as a high-purity product. Although bromides have been mentioned above as organic salts, iodides can also be used in the same manner.

[0065] The concentration of at least one anion species selected from halide ions, halide ions, and halide ions contained in the first solution may be appropriately set so as to achieve a desired concentration when the first solution is mixed with the second solution to form the treatment solution of the present invention. For example, when mixing the first and second solutions without generating hypohalite ions, the concentration of the anion species contained in the first solution may be set taking into account the volume of the treatment solution after mixing. On the other hand, when mixing the first and second solutions to generate hypohalite ions, the concentration of halide ions contained in the first solution may be set taking into account the amount of halide ions consumed to generate hypohalite ions. For example, from the viewpoint of effectively suppressing roughness of the metal surface, the concentration of at least one anion species selected from halide ions, halite ions, and halide ions in the first solution is usually 0.4 mol / L or more, preferably 0.7 mol / L or more, and more preferably 1.5 mol / L or more, and is usually 6.0 mol / L or less, preferably 2.5 mol / L or less, and more preferably 1.5 mol / L or less. The above range may also be applied to the total concentration of anion species in the first solution.

[0066] The first solution is Anion species It may contain other components, such as the above-mentioned solvents and other additives.

[0067] The pH of the first solution is not particularly limited, and is preferably adjusted appropriately so that, for example, the desired pH of the treatment liquid of the present invention is achieved by mixing with the second solution. To suppress pH changes after mixing, the pH is preferably 7 or higher and 14 or lower, and more preferably 8 or higher and 14 or lower. A solution within this pH range can minimize the pH drop that occurs upon mixing with the second solution described below, enabling the final treatment liquid to be produced, stored, and used stably. When the pH of the first solution is set to less than 8, the pH and volume of the first solution can be adjusted so that the pH of the treatment liquid after mixing with the second solution is alkaline. Other components contained in the first solution are preferably the solvents, other additives, and pH adjusters described above for the treatment liquid of the present invention.

[0068] (Method for preparing the second solution) In the present invention, the method for preparing the second solution is not particularly limited. Specifically, the second solution of the present invention can be prepared by adding hypohalite ions to a solvent such as water, and then adding additives as needed. Examples of the hypohalite ions that can be used include sodium hypochlorite, sodium hypobromite, tetraalkylammonium hypochlorite, and tetraalkylammonium hypobromite. Among these, it is preferable to use tetraalkylammonium hypochlorite or tetraalkylammonium hypobromite, which do not contain metals that can reduce yields in semiconductor fabrication processes. The tetraalkylammonium hypohalite can be prepared by a known method. For example, an aqueous solution containing tetraalkylammonium hypochlorite can be prepared by preparing an aqueous solution of tetraalkylammonium hydroxide and then blowing chlorine into it. Alternatively, a solution containing tetraalkylammonium hypochlorite can be prepared by contacting a tetraalkylammonium hydroxide solution with a cation-exchange ion exchange resin, converting the cations in the ion exchange resin into tetraalkylammonium ions, and then passing a sodium hypochlorite solution through the resin to exchange the sodium ions for the tetraalkylammonium ions.

[0069] The concentration of hypohalite ions contained in the second solution may be appropriately set so as to achieve a desired concentration when mixed with the first solution to form the treatment solution of the present invention. For example, when mixing the first and second solutions without generating hypohalite ions, the concentration of hypohalite ions contained in the second solution may be set taking into account the volume of the treatment solution after mixing. On the other hand, when mixing the first and second solutions to generate hypohalite ions, the concentration of hypohalite ions contained in the second solution may be set taking into account the amount of hypohalite ions consumed to generate hypohalite ions. For example, from the viewpoint of effectively suppressing roughness of the metal surface, the concentration of hypohalite ions in the second solution is usually 0.05 mol / L or more, preferably 0.1 mol / L or more, and more preferably 0.2 mol / L or more, and is usually 3.5 mol / L or less, preferably 0.8 mol / L or less, more preferably 0.3 mol / L or less, and even more preferably 0.2 mol / L or less.

[0070] The ratio of the amount of the second solution used to the amount of the first solution used (amount of the second solution used / amount of the first solution used) is not particularly limited, but from the viewpoint of effectively suppressing roughness of the metal surface, the weight ratio is usually 0.1 or more, preferably 0.15 or more, and more preferably 0.25 or more, and is usually 10 or less, preferably 6 or less, and more preferably 4 or less. The ratio (anion species concentration / hypohalite ion concentration) of the concentration (mol / L) of at least one anion species in the first solution (which may be the total concentration of anion species in the first solution) to the concentration (mol / L) of hypohalite ions in the second solution is not particularly limited, but from the viewpoint of effectively suppressing roughness of the metal surface, it is usually 2 or more, preferably 4 or more, more preferably 6 or more, and even more preferably 8 or more, and is usually 500 or less, preferably 200 or less, more preferably 50 or less, and even more preferably 10 or less.

[0071] The second solution is hypohalite ions It may contain other components, such as the above-mentioned solvents and other additives.

[0072] The pH of the second solution is not particularly limited, and it is preferably set appropriately so that, for example, the pH of the treatment liquid of the present invention is desired after mixing with the first solution. To suppress pH changes after mixing, the pH is preferably 7 to 14, more preferably 10 to 14, and particularly preferably 12 to 14. A solution within this pH range can minimize the pH drop that occurs when mixed with the first solution, enabling the treatment liquid of the present invention to be stably produced, stored, and used. Other components contained in the second solution are preferably the solvents, other additives, and pH adjusters described above for the treatment liquid of the present invention.

[0073] The oxidizing power of the anion species contained in the first solution and the oxidizing power of the hypohalite ions contained in the second solution are not particularly limited and can be set appropriately, but from the viewpoint of effectively suppressing roughening of the metal surface, it is preferable that the oxidizing power of the hypohalite ions is higher than the oxidizing power of the anion species.

[0074] The production and storage of the treatment solution and preparation materials of the present invention are preferably carried out at low temperatures, protected from light, and free of amines. Production and storage at low temperatures, protected from light, and free of amines is expected to suppress decomposition of the oxidizing agent and anionic species in the treatment solution. Furthermore, production and storage of the treatment solution and preparation materials in a container filled with an inert gas prevents carbon dioxide contamination, thereby maintaining the stability of the treatment solution. Furthermore, the inner surface of the container, i.e., the surface that comes into contact with the treatment solution, is preferably made of glass or an organic polymer material. Forming the inner surface of the reaction vessel from glass or an organic polymer material further reduces the inclusion of impurities such as metals, metal oxides, and organic substances.

[0075] From the viewpoint of effectively suppressing roughness of the metal surface, it is preferable that onium ions are contained in at least one solution selected from the first solution and the second solution, and it is particularly preferable that onium ions are contained in both the first solution and the second solution. The onium ions may be the same as those described above in relation to the treatment liquid of the present invention. The concentration of the onium ions in at least one solution selected from the first solution and the second solution is not particularly limited, but from the viewpoint of effectively suppressing roughness of the metal surface, it is usually 0.00002 mol / L or more, preferably 0.002 mol / L or more, and more preferably 0.02 mol / L or more, and is usually 6.0 mol / L or less, preferably 4.0 mol / L or less, more preferably 2.0 mol / L or less, and even more preferably 1.0 mol / L or less. Furthermore, the total concentration of onium ions contained in the first solution and the second solution relative to the total amount of these solutions is not particularly limited, but from the viewpoint of effectively suppressing roughness of the metal surface, it is usually 0.00001 mol / L or more, preferably 0.001 mol / L or more, and more preferably 0.01 mol / L or more, and is usually 6.0 mol / L or less, preferably 3.0 mol / L or less, more preferably 2.0 mol / L or less, and even more preferably 1.0 mol / L or less.

[0076] (Composition of preparation materials) In the method for producing a treatment liquid of the present invention, the concentrations of the components contained in the two preparation materials, the first solution and the second solution, are not particularly limited, and may be adjusted so as to achieve the desired composition when the preparation materials are mixed to form a treatment liquid.

[0077] Specifically, when a processing solution containing 0.001 mol / L or more and 2.0 mol / L or less of hypochlorite ions and containing, as anion species, 0.30 mol / L or more and 5.00 mol / L or less of chloride ions and 0.3 mol / L or more and 1.50 mol / L or less of chlorate ions is required, the first solution is a solution containing 0.60 mol / L or more and 6.0 mol / L or less of chloride ions and 0.60 mol / L or more and 3.0 mol / L or less of chlorate ions, and the second solution is a solution containing 0.002 mol / L or more and 4.0 mol / L or less of hypochlorite ions, and these preparation materials are mixed together before processing the semiconductor wafers to prepare the processing solution for semiconductor wafers.

[0078] Alternatively, to obtain a treatment solution containing hypochlorite ions and hypobromite ions at 0.001 mol / L or more and 2.0 mol / L or less as hypohalite ions in the treatment solution, and containing chloride ions at 0.30 mol / L or more and 5.0 mol / L or less and chlorate ions at 0.3 mol / L or more and 1.50 mol / L or less as anion species, the first solution is a solution containing chloride ions at 0.60 mol / L or more and 6.0 mol / L or less, bromide ions at 0.002 mol / L or more and 0.40 mol / L or less, and chlorate ions at 0.60 mol / L or more and 3.00 mol / L or less, and the second solution is a solution containing hypochlorite ions at 0.002 mol / L or more and 0.002 mol / L or less. mol / L The solution is prepared to have a concentration of 4.0 mol / L or less, and these preparation materials are mixed together before processing semiconductor wafers to prepare a processing solution for semiconductor wafers.

[0079] (Method of mixing ingredients for preparation) The mixing method in the step of mixing the first solution and the second solution can be any method widely known as a method for mixing semiconductor chemicals. Suitable examples include a method using a mixing tank, a method of mixing within the piping of a semiconductor manufacturing apparatus (in-line mixing), or a method of mixing by simultaneously pouring multiple solutions onto a wafer. When generating hypohalite ions by mixing the first solution and the second solution, it is preferable to mix the preparation materials in advance and contact the semiconductor wafer after sufficient hypohalite ions have been generated, in order to ensure the generation of hypohalite ions.

[0080] The temperature at which the preparation materials are mixed is not particularly limited as long as the mixed treatment liquid is homogeneous, and is generally set appropriately within the range of 0°C to 80°C. When generating hypohalite ions by mixing the preparation materials, the faster the hypohalite ions are generated, the better, so the shorter the mixing time is, the better. One way to shorten the mixing time is to increase the temperature during mixing, but the higher the temperature, the more likely the decomposition of the hypohalite ions contained in the second solution or the mixed treatment liquid tends to proceed. For these reasons, when generating hypohalite ions by mixing the preparation materials, the temperature during mixing of the preparation materials is preferably 10°C to 60°C, more preferably 20°C to 50°C.

[0081] Furthermore, when the first solution and the second solution are mixed without generating hypohalite ions, the mixing time of the preparation materials may be continued until the temperature and composition concentration of the mixed treatment solution become uniform, and may be set appropriately within 30 minutes. On the other hand, when the first solution and the second solution are mixed to generate hypohalite ions, a longer mixing time is better to ensure the generation of hypohalite ions, but from the viewpoint of throughput, the mixing time may be set appropriately within 60 minutes. Furthermore, there is no particular need to set a lower limit for the mixing time, but it is usually 5 minutes or more.

[0082] By the above-mentioned manufacturing method, a semiconductor wafer processing solution, particularly a semiconductor wafer processing solution of the present invention, can be manufactured. By using the semiconductor wafer processing solution manufactured by this manufacturing method or the above-mentioned processing solution of the present invention, not only can the wafer processing efficiency per unit time be improved, but it can also be suitably used as a processing solution for, for example, a metal etch-back process in a semiconductor manufacturing process, which requires precise etching control for wiring materials. Furthermore, since it has the same effect on metals other than ruthenium, it can be used as an etching solution for metals contained in semiconductor wafers, not just ruthenium. Hereinafter, a method of using the processing liquid for semiconductor wafers manufactured by the present manufacturing method or the processing liquid described above (hereinafter, these are also collectively referred to as "processing liquid for semiconductor wafers of the present invention") will be described.

[0083] Another embodiment of the present invention relates to a preparation material for preparing a processing solution for semiconductor wafers, which comprises a first solution containing at least one anion species selected from halide ions, halite ions, and halide ions, and a second solution containing hypohalite ions, and the conditions for these first and second solutions can be similarly applied to the conditions for the first and second solutions described above. The contents of the first solution and the second solution contained in the preparation material of the present invention are not particularly limited. Made The material may consist of only the first solution and the second solution.

[0084] The content of the first solution in the preparation material is not particularly limited, but from the viewpoint of effectively suppressing roughness of the metal surface, it is usually 10% by weight or more, preferably 15% by weight or more, and more preferably 20% by weight or more, and is usually 90% by weight or less, preferably 60% by weight or less, more preferably 40% by weight or less, and even more preferably 30% by weight or less. The content of the second solution in the preparation material is not particularly limited, but from the viewpoint of effectively suppressing roughness of the metal surface, it is usually 10% by weight or more, preferably 40% by weight or more, more preferably 60% by weight or more, and even more preferably 70% by weight or more, and is usually 90% by weight or less, preferably 85% by weight or less, and more preferably 80% by weight or less.

[0085] (kit) Another embodiment of the present invention is a kit (also simply referred to as "kit") for preparing a processing liquid for semiconductor wafers, which includes at least a first solution containing at least one anion species selected from halide ions, haloid ions, and halide ions, and a second solution containing hypohalite ions (a kit for preparing a processing liquid for semiconductor wafers). The first solution and the second solution may be the first solution and the second solution described above. The kit may be embodied in any manner, including, for example, a container containing (or storing or holding) the first solution and a container containing (or storing or holding) the second solution. Alternatively, the kit may be embodied as a container having two or more solution storage spaces, two of which contain the first solution and the second solution, respectively. The first and second solutions can be stored, transported, and used in the containers. Furthermore, by mixing the solutions contained in such a kit, a processing solution for semiconductor wafers can be prepared.

[0086] When used in the form of a kit comprising a container containing the first solution and a container containing the second solution, the form of each container is not particularly limited, and the volume of each container can be appropriately designed depending on the amount of solution to be stored. For example, 20,000 cm 3 More than 200000cm 3 It may be less than 4000 cm 3 More than 20000cm 3The containers may be made of a material that is less likely to react with the solution contained therein and that causes less elution of impurities. The amount of solution contained in each container can be appropriately designed depending on the amount of treatment liquid that is ultimately desired to be obtained. Containers that can be used include, for example, PP (polypropylene), PE (polyethylene), PTFE, PFA, etc., or other materials such as metal or glass containers with the inner walls coated with these materials. In addition, the above-mentioned volumes and materials can also be applied to the volumes of the solution storage spaces and the materials of the container in an embodiment in which the container has two or more solution storage spaces, two of which store a first solution and a second solution, respectively.

[0087] The kit may be a kit containing only the first solution and the second solution, or may be a kit containing three or more solutions containing solutions other than these solutions. However, from the viewpoint of simplifying the manufacturing process of the treatment solution, 1 of Preferably, the kit comprises only the solution and the second solution. Furthermore, the method for producing the kit is not particularly limited, and the kit can be produced by a known method depending on each embodiment.

[0088] (Use of semiconductor wafer processing liquid) As described above, the semiconductor wafer treatment solution of the present invention not only improves wafer treatment efficiency per unit time, but can also be suitably used as a treatment solution for, for example, a metal etch-back process in a semiconductor manufacturing process, which requires precise etching control of wiring materials. Furthermore, since it has the same effect on metals other than ruthenium, it can be used as an etching solution for metals contained in semiconductor wafers, not just ruthenium.

[0089] Specific examples of metals contained in semiconductor wafers to which the treatment solution of the present invention is applied include Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W, and the treatment solution contains at least one metal selected from these. These metals can be used as a single metal species or as an alloy of multiple metal species. Among these metals, metals such as Ru, Rh, Co, Cu, Mo, and W, which are useful as wiring layers, are preferably used. Of these, Ru, Co, Mo, and W are preferred. The metal film may be formed by any method, and methods widely known in the semiconductor manufacturing process, such as CVD, ALD, PVD, sputtering, and plating, can be used.

[0090] The metal may be an intermetallic compound, an ionic compound, a complex, or the like. The metal may be exposed on the surface of the wafer, or may be covered with another metal, a metal oxide film, an insulating film, a resist, or the like. Even if the metal is covered with another material, it is possible to obtain a sufficient etching rate and dissolution of the metal when the metal comes into contact with the treatment liquid of the present invention. smoothness It becomes possible to achieve both of these.

[0091] For example, the process for using the treatment solution of the present invention in a metal wiring formation process is as follows: First, a substrate made of a semiconductor (e.g., Si) is prepared. The prepared substrate is subjected to an oxidation treatment to form a silicon oxide film on the substrate. Then, an interlayer insulating film made of a low dielectric constant (Low-k) film is formed, and via holes are formed at predetermined intervals. After the via holes are formed, a metal is filled into the via holes by thermal CVD, and a metal film is then formed. By treating this metal film with the treatment solution of the present invention, it is possible to perform planarization while maintaining a sufficient etching rate.

[0092] The method for bringing the treatment solution of the present invention into contact with the semiconductor wafer having the metal layer formed thereon is not particularly limited. For example, the treatment solution of the present invention may be poured over the semiconductor wafer while the semiconductor wafer is being rotated, or the semiconductor wafer may be immersed in a container filled with the treatment solution of the present invention to bring the treatment solution into contact with the semiconductor wafer.

[0093] The temperature at which metals are etched with the treatment solution of the present invention is not particularly limited and may be appropriately determined taking into consideration the etching rate of the metal, the stability of the treatment solution, and the like. Since the stability of the treatment solution tends to deteriorate as the temperature increases, a lower treatment temperature is preferable. On the other hand, the etching rate of the metal tends to increase as the temperature increases. From the viewpoint of achieving both stability and etching rate of the treatment solution, the temperature at which metals are etched is preferably 10°C or higher and 90°C or lower, more preferably 15°C or higher and 70°C or lower, and most preferably 20°C or higher and 60°C or lower.

[0094] The treatment time when etching metal with the treatment solution of the present invention is in the range of 0.1 minutes or more and 120 minutes or less, preferably 0.3 minutes or more and 60 minutes or less, and can be appropriately selected depending on the etching conditions and the semiconductor device used. After using the treatment solution of the present invention, the treatment solution can be removed by washing the semiconductor wafer surface that has come into contact with the treatment solution with a rinse solution or the like. The rinse solution used after using the treatment solution of the present invention is not particularly limited, and organic solvents such as alcohol or deionized water can be used. After rinsing, the semiconductor wafer can be subjected to the next process, such as laminating other wiring materials, after drying the wafer surface as necessary. [Example]

[0095] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The tetramethylammonium hypochlorite, tetramethylammonium chlorate, and evaluation semiconductor wafers used in the examples and comparative examples were prepared as follows. In the following examples and comparative examples, the concentrations of metals and metal ions were measured using an inductively coupled plasma mass spectrometer (ICP-MS, Agilent 8900, manufactured by Agilent Technologies) to ensure they were 0.01 ppt to 1 ppb. Specifically, for example, in Example 1, the concentrations were Li 0.01 ppt, Na 8 ppt, Mg 1 ppt, Al 50 ppt, K 2 ppt, Ca 10 ppt, Cr 8 ppt, Mn 0.5 ppt, Fe 11 ppt, Co 3 ppt, Ni 2 ppt, Cu 0.2 ppt, Zn 11 ppt, Ag 0.01 ppt, Cd 0.5 ppt, Ba 2 ppt, and Pb 10 ppt.

[0096] (Preparation of semiconductor wafers for metal etching performance evaluation) The ruthenium film, molybdenum film, and tungsten film used in the examples and comparative examples were formed as follows. The ruthenium film and molybdenum film were obtained by forming an oxide film on a silicon wafer using a batch-type thermal oxidation furnace, and then forming a 1200 Å thick ruthenium film or a 1000 Å thick molybdenum film on top of that using a sputtering method. The tungsten film was obtained by similarly forming a thermal oxide film and then depositing 8000 Å thick tungsten film by a CVD method. Growth The sheet resistance was measured using a four-point probe resistance meter (Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and converted into film thickness, which was used as the metal film thickness before etching.

[0097] (Preparation of tetramethylammonium hypochlorite ((CH3)4NClO)) A 2 L glass three-neck flask (manufactured by Cosmos Bead) was charged with 583.4 g of a 25 wt % aqueous solution of tetramethylammonium hydroxide and 363.4 g of ion-exchanged water to obtain a 15.4 wt % aqueous solution of tetramethylammonium hydroxide, the pH of which was 14.2.

[0098] Next, a rotor (AsOne, 30 mm long x 8 mm diameter) was placed in a three-neck flask, and a thermometer and thermometer protection tube (Cosmos Bead, bottom-sealed type) were inserted into one opening. The other opening was connected to a chlorine gas cylinder and a nitrogen gas cylinder. The tip of a PFA tube (Flon Industries, F-8011-02) was immersed in the bottom of the solution, and the remaining opening was connected to a gas washing bottle (AsOne, model number 2450 / 500) filled with 5 wt% sodium hydroxide aqueous solution. Nitrogen gas was passed through the PFA tube at 200 ccm (25 °C) for 20 minutes to expel carbon dioxide from the gas phase.

[0099] Then, a magnetic stirrer (AsOne, C-MAG HS10) was placed at the bottom of the three-neck flask and rotated at 300 rpm. While the outer periphery of the three-neck flask was cooled with ice water, chlorine gas (Fujiox, specified purity 99.4%) was fed at 200 ccm (25°C) for 180 minutes to obtain a 0.75 mol / L tetramethylammonium hypochlorite solution (containing 0.75 mol / L tetramethylammonium chloride and 0.1 mol / L tetramethylammonium hydroxide). The liquid temperature during the reaction was 11°C.

[0100] (Preparation of tetramethylammonium chlorate ((CH3)4NClO3)) A saturated solution was obtained by adding sodium chlorate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to ion-exchanged water and storing it in a refrigerator for 24 hours. The precipitated sodium chlorate was collected by filtration. The collected sodium chlorate was diluted with ultrapure water and analyzed using an ion chromatography analyzer. The CO3 - , SO4 - , and Cl - By analyzing the water, it was confirmed that the impurities Na2CO3, Na2SO4, and NaCl were reduced. By repeating the above purification process, CO3 - , SO4 - , and Cl - It was confirmed that each was 500 ppb or less, and purified sodium chlorate was obtained.

[0101] Next, 200 mL of a strongly acidic ion exchange resin (Organo Corporation, Amberlite IR-120BNa) was placed in a glass column (AsOne Corporation, Biocolumn CF-50TK) with an inner diameter of approximately 45 mm. Subsequently, 1 L of 1 N hydrochloric acid (Fujifilm Wako Pure Chemical Industries, Ltd., for volumetric analysis) was passed through the ion exchange resin column to convert the ion exchange resin to the hydrogen form, and 1 L of ultrapure water was passed through to wash the ion exchange resin. Furthermore, 2 L of 2.38% tetramethylammonium hydroxide solution was passed through the ion exchange resin, which had been converted to the hydrogen form, to convert the hydrogen form to the tetramethylammonium form. After the ion exchange, 1 L of ultrapure water was passed through to wash the ion exchange resin.

[0102] 6.4 g of purified sodium chlorate was placed in a fluororesin container, and 93.6 g of ultrapure water was added to prepare a 6.4 wt. % sodium chlorate aqueous solution. The prepared sodium chlorate aqueous solution was passed through an ion exchange resin that had been converted to a tetramethylammonium form. The recovered tetramethylammonium chlorate was analyzed for Na concentration using high-frequency inductively coupled plasma atomic emission spectroscopy (iCAP6500DuO, Thermo Scientific) to confirm that ion exchange had been completed satisfactorily. If insufficient, the above procedure was repeated to obtain a 10 wt. % tetramethylammonium chlorate solution with a Na concentration of 500 ppb or less. The resulting solution was heat-treated to obtain tetramethylammonium chlorate powder.

[0103] (Other reagents) In addition to the above, the following reagents were used in the Examples and Comparative Examples. Tetramethylammonium chloride ((CH3)4NCl): Tokyo Chemical Industry Co., Ltd. Tetramethylammonium bromide ((CH3)4NBr): Tokyo Chemical Industry Co., Ltd. Sodium hypochlorite pentahydrate (NaClO 5H2O): Wako Pure Chemical Industries, Ltd. Sodium chloride (NaCl): Fujifilm Wako Pure Chemical Industries, Ltd. Sodium bromide (NaBr): Fujifilm Wako Pure Chemical Industries, Ltd. Tetrapropylammonium chloride ((C3H7)4NCl): Tokyo Chemical Industry Co., Ltd. 1,1-Dimethylpiperidinium chloride (CH 16 NCl): Tokyo Chemical Industry Co., Ltd. Hexamethonium chloride dihydrate (C 12 H 30 N2Cl2·2H2O: manufactured by Tokyo Chemical Industry Co., Ltd. 15 wt% HCl: manufactured by Kanto Chemical Co., Ltd. (prepared by diluting 35 wt% HCl with ultrapure water) 1 mol / L NaOH: Fujifilm Wako Pure Chemical Industries, Ltd.

[0104] <Examples 1 to 38 and Comparative Examples 1 to 27> (Manufacturing of semiconductor wafer processing solutions) The 0.75 mol / L tetramethylammonium hypochlorite aqueous solution, tetramethylammonium chlorate powder, tetramethylammonium chloride, tetramethylammonium bromide, ultrapure water, 15 wt% HCl, and 1 mol / L NaOH obtained in the above manufacturing examples were mixed to obtain 100 mL of a treatment solution with the composition shown in Tables 1 to 3. However, in Examples 16 and 34 and Comparative Examples 8 and 21, sodium hypochlorite pentahydrate was used instead of the 0.75 mol / L tetramethylammonium hypochlorite aqueous solution, sodium chloride was used instead of tetramethylammonium chloride, and sodium bromide was used instead of tetramethylammonium bromide. The hypohalite ion concentration, anion species concentration, and pH in the resulting semiconductor wafer treatment solution were measured using the following methods. The resulting treatment solution was used to evaluate the metal etching performance and post-etching surface evaluation described below. The results are shown in Tables 1 to 3.

[0105] (Method for measuring hypobromite ion and hypochlorite ion concentrations) The concentrations of hypobromite ions and hypochlorite ions were measured using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). Calibration curves were prepared using aqueous solutions of hypobromite ions and hypochlorite ions with known concentrations, and the concentrations of hypobromite ions and hypochlorite ions in the produced treatment solution were determined.

[0106] (Method for measuring the concentration of anionic species) The concentration of anion species in the semiconductor wafer treatment solution was measured using an ion chromatography analyzer (DIONEX INTEGRION HPLC, Thermo Scientific). KOH was used as the eluent, and the solution was passed through at a flow rate of 1.2 mL / min. The column used was an anion analysis column for hydroxide-based eluents (AS15, Thermo Scientific), and the column temperature was set to 30°C. After removing background noise with a suppressor, the anion species in the treatment solution were quantified using an electrical conductivity detector.

[0107] (pH measurement method) The pH of 10 mL of the treatment solution prepared in the Examples and Comparative Examples was measured using a desktop pH meter (LAQUA F-73, manufactured by Horiba, Ltd.) The pH measurement was carried out after the treatment solution was prepared and stabilized at 25°C.

[0108] (Evaluation of metal etching performance) 60 mL of the treatment solution for this example was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL). Each semiconductor wafer piece for evaluation, measuring 10 x 20 mm, was immersed in the treatment solution at 25°C or 50°C for 1 minute, and the change in film thickness before and after treatment was divided by the immersion time to calculate the etching rate, which was then evaluated according to the following criteria. In all cases, ratings A to C were acceptable, and rating D was unacceptable. (Ruthenium film, Molybdenum film) A:>50Å / min B:50~20Å / min C: 20-10Å / min (acceptable level) D: Cannot be etched (tungsten film) A:>500Å / min B:500~100Å / min C: 100 to 10Å / min (acceptable level) D: Cannot be etched

[0109] (Surface evaluation after etching) The metal surface was observed before and after etching using a field emission scanning electron microscope (JSM-7800F Prime, manufactured by JEOL Ltd.) to check for the presence or absence of surface roughness, and was evaluated according to the following criteria: Surface roughness was graded from least to most severe, A to D, with grades A to C being acceptable levels and grade D being unacceptable. A: No surface roughness is observed B: Slight surface roughness C: Roughness is observed on the entire surface, but the roughness is shallow D: Roughness is observed over the entire surface, and the roughness is deep

[0110] [Table 1]

[0111] [Table 2]

[0112] [Table 3]

[0113] <Examples 39 to 41, Comparative Example 28> First and second solutions (preparation materials) with the compositions shown in Table 4 were prepared, and each solution was stored separately in a pure bottle (20 L capacity, PE inner wall, light-shielding, made of Kodama resin) sealed with N2 and kept at 25°C. The solutions stored in each container were mixed at the mixing ratio (volume ratio) shown in Table 4 to obtain a treatment solution with the composition shown in Table 5. The etching rate and smoothness of the metal surface were evaluated in the same manner as in Example 1. The results are shown in Table 5.

[0114] [Table 4]

[0115] [Table 5]

[0116] <Example 42> The treatment solution of Example 35 and the treatment solution of Example 41 (first and second solutions (preparation materials)) were prepared, and a 150-day storage test was carried out in the same manner as in Example 1, with the day on which the solution was prepared being considered the first day (storage conditions: nitrogen sealed, protected from light, 25°C). The treatment solution of Example 41 was stored as the first and second solutions, and mixed immediately before evaluation to prepare the treatment solution. The results are shown in Table 6.

[0117] [Table 6]

[0118] <Examples 43 to 56> A treatment solution was obtained having the composition shown in Table 7. The etching rate and smoothness of the metal surface were evaluated in the same manner as in Example 1. The results are shown in Table 7.

[0119] [Table 7]

[0120] Example 57 The treatment solutions of Comparative Example 13 and Example 21 were prepared, and starting from the day on which the solutions were prepared, a 150-day storage test was carried out in the same manner as in Example 1 (storage conditions: nitrogen sealed, shielded from light, 25°C). The results are shown in Table 8.

[0121] [Table 8]

[0122] <Example 58> The treatment solutions of Comparative Example 1 and Example 2 were prepared, and starting from the day on which the solutions were prepared, a 150-day storage test was carried out in the same manner as in Example 1 (storage conditions: nitrogen sealed, shielded from light, 25°C). The results are shown in Table 9.

[0123] [Table 9]

[0124] Table 1 ~5 As shown in Table 1, when the treatment solutions shown in Comparative Examples 1 to 28 were used, the surfaces after etching were all rough, and it was not possible to achieve both an etching rate and smoothness. On the other hand, as shown in Tables 1 to 3, the treatment solutions of the present invention shown in Examples 1 to 38 provided good surface smoothness after etching, and therefore it was possible to achieve both an etching rate and smoothness. As shown in Tables 4 and 5, in Examples 39 to 41, a first solution containing an anion species and a second solution containing an oxidizing agent were prepared, and the two solutions were mixed before etching each evaluation semiconductor wafer to prepare a treatment solution, and it was possible to achieve both an etching rate and smoothness. As shown in Table 6, in Example 4 1 In this study, the performance of one-component and two-component (kit) treatment solutions (Examples 35 and 41) was compared. Compared to the one-component type, the two-component (kit) treatment solution, which was prepared immediately before metal treatment, exhibited superior etching rate and surface smoothness over a long period of time. As shown in Table 7, Examples 43 to 56 evaluated the properties of treatment solutions to which onium ions were added in addition to anionic species. The addition of onium ions further improved surface smoothness while maintaining the etching rate. As shown in Tables 8 and 9, it was revealed that treatment solutions according to embodiments of the present invention, which contain a higher amount of anionic species, exhibited superior stability in terms of etching rate and surface smoothness.

Claims

1. A processing liquid for semiconductor wafers, The treatment solution contains at least one hypohalite ion, and at least two or more anion species selected from a halate ion, a halite ion, and a halide ion, the content of the at least one anion species relative to the treatment liquid is 0.30 mol / L or more and 6.00 mol / L or less; A processing solution for semiconductor wafers, comprising at least hypobromite ions as the hypohalite ions, the content of the hypobromite ions being 0.0010 mol / L or more and 0.20 mol / L or less relative to the processing solution.

2. 2. The semiconductor wafer processing solution according to claim 1, wherein the at least one anion species contained in the processing solution in an amount of 0.30 mol / L or more and 6.00 mol / L or less is a halide ion.

3. 3. The semiconductor wafer processing solution according to claim 1, wherein the content of the hypohalite ions in the processing solution is 0.0010 mol / L or more and 4.00 mol / L or less.

4. 4. The semiconductor wafer processing liquid according to claim 1, wherein the hypohalite ions include at least one selected from hypochlorite ions and hypobromite ions.

5. 5. The semiconductor wafer processing liquid according to claim 4, wherein the hypohalite ions include hypochlorite ions and hypobromite ions.

6. The semiconductor wafer treating solution according to any one of claims 1 to 5, wherein the treating solution further contains onium ions.

7. The semi-finished product according to any one of claims 1 to 6, wherein the pH of the treatment liquid is 7 or more and 14 or less. Processing fluid for conductor wafers.

8. 8. The semiconductor wafer treatment solution according to claim 1, wherein the treatment solution contains any one metal selected from lithium, sodium, potassium, aluminum, magnesium, calcium, chromium, manganese, iron, nickel, cobalt, copper, silver, cadmium, barium, zinc, and lead, and the concentration of the metal is 0.01 ppt or more and 1 ppb or less on a mass basis.

9. 9. The semiconductor wafer treatment solution according to claim 1, wherein the semiconductor wafer contains at least one metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W.

10. preparing a first solution containing at least one anion species selected from halate ions, halite ions, and halide ions; preparing a second solution containing hypohalite ions; and mixing the first solution and the second solution; A method for producing a processing liquid for semiconductor wafers, wherein the oxidizing power of hypohalite ions contained in the second solution is higher than the oxidizing power of anion species contained in the first solution.

11. 11. The method for producing a processing solution for semiconductor wafers according to claim 10, wherein at least one of the anion species contained in the first solution is a bromide ion, and the hypohalite ion contained in the second solution is a hypochlorite ion.

12. 12. The method for producing a processing liquid for semiconductor wafers according to claim 10, wherein at least one solution selected from the first solution and the second solution contains onium ions.

13. The method for producing a processing solution for semiconductor wafers according to claim 12 , wherein the first solution and the second solution each contain onium ions.

14. A kit for preparing a processing solution for semiconductor wafers, the kit comprising at least a first solution containing at least one anion species selected from halide ions, haloid ions, and halide ions, and a second solution containing hypohalite ions, The kit, wherein the oxidizing power of the hypohalite ions contained in the second solution is higher than the oxidizing power of the anionic species contained in the first solution.

15. 15. The kit of claim 14, wherein at least one of the anionic species contained in the first solution is bromide ion, and the hypohalite ion contained in the second solution is hypochlorite ion.

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