Processing liquid for semiconductor

Abstract

To provide a processing liquid which includes an excellent dissolution capability against a transition metal containing material, can realize an excellent smoothness, and has a stable etching rate.SOLUTION: The present invention provides a processing liquid for a semiconductor used for removing a transition metal containing material on a substrate. The processing liquid for the semiconductor contains: at least one kind selected from a group of specific halogen oxygen acid ions, bromide ions, bromous acid ions, bromate ions, chloride ions, chlorate ions, iodate ions, iodide ions, and triiodide ions; and at least one kind of metals selected from a group of Ca, Na, K, Cr, Ni, and Al. A concentration of any one kind of metals of Ca, Na, K, Cr, Ni, and Al is 0.1 ppt or more and 200 ppt or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a semiconductor processing solution used in metal wiring processing in the manufacturing process of semiconductor elements. [Background technology]

[0002] In semiconductor elements, wiring layers are formed for the purpose of extracting electric signals generated by transistors to the outside. Semiconductor elements are becoming finer year by year, and if a material with low electromigration resistance or high resistance is used, the reliability of the semiconductor element decreases and high-speed operation is hindered. Therefore, materials with high electromigration resistance and low resistance are desired as wiring materials.

[0003] As such a material having high electromigration resistance and low resistance value, for example, aluminum and copper have been used so far, and recently, tungsten, cobalt, molybdenum, ruthenium, etc. are being considered. Forming a wiring layer on a semiconductor element includes a process of processing the wiring material, and this process uses dry or wet etching.

[0004] When wet etching wiring materials, if the surface condition after etching is rough, there is a problem that when a new metal film is formed on top of it, the electrical resistance increases and the electrical characteristics deteriorate. Therefore, there is a demand for a processing solution that can maintain the surface state after wet etching in a smooth state. As a method for maintaining the surface state after etching in a smooth state, there is a method of adding a new additive to the processing solution, and methods such as modifying the surface state by the additive and controlling the etching performance have been considered. In addition, if the etching rate is stable, there is little variation in the amount of etching on the wafer or between wafers, and the yield is less likely to occur. In Patent Document 1, additives capable of suppressing deterioration of the surface state after etching are studied. In this invention, a predetermined amount of chlorite ions is added to the hypochlorite ions in the treatment liquid used for etching. It is said that the addition of chlorite ions makes it possible to control the redox potential, which is effective for the smoothness of the surface state of the metal wiring after treatment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-218436 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors investigated the removability of transition metal-containing materials and the stability of the etching rate using the method disclosed in Patent Document 1, and found that although the method has excellent dissolving ability, the smoothness of the treated area is insufficient, and hypochlorite ions react with chlorite ions, causing the hypochlorite ions to decompose, resulting in an insufficient stability of the etching rate and requiring further improvement. In addition, in the wet etching process of semiconductor wafers, in addition to the smoothness of the surface state of the metal wiring after processing, a stable etching rate for transition metal-containing substances is required. If the etching rate is not stable, the etching amount on the wafer or between wafers may vary depending on the storage period, which may increase the yield rate. Therefore, an object of the present invention is to provide a treatment liquid that has excellent dissolving ability for transition metal-containing substances, can achieve excellent smoothness, and has a stable etching rate. [Means for solving the problem]

[0007] The present inventors have conducted intensive research to solve the above problems. And, it has been found that the above problems can be solved by a semiconductor processing solution containing at least one halogen oxygen acid ion selected from the group consisting of hypobromite ion, hypochlorite ion, and periodate ion, at least one ion selected from the group consisting of bromide ion, bromite ion, bromate ion, chloride ion, chlorate ion, iodate ion, iodide ion, and triiodide ion, and at least one metal selected from the group consisting of Ca, Na, and K. By containing at least one metal selected from the group consisting of Ca, Na, and K, the smoothness of the treated area is maintained, and by containing at least one ion selected from the group consisting of bromide ion, bromite ion, bromate ion, chloride ion, chlorate ion, iodate ion, iodide ion, and triiodide ion, the etching rate of the processing solution is stable, and the present invention has been completed. That is, the configuration of the present invention is as follows.

[0008] Item 1: A semiconductor processing solution used to remove transition metal-containing substances on a substrate, comprising: the semiconductor processing solution contains at least one halogen oxygen acid ion selected from the group consisting of hypobromite ions, hypochlorite ions, and periodate ions; at least one ion selected from the group consisting of bromide ion, bromite ion, bromate ion, chloride ion, chlorate ion, iodate ion, iodide ion, and triiodide ion; A semiconductor processing solution containing at least one metal selected from the group consisting of Ca, Na, K, Cr, Ni, and Al, and having a concentration of any one of Ca, Na, K, Cr, Ni, and Al of 0.1 ppt by mass or more and 200 ppt by mass or less. Item 2 In the semiconductor processing solution, The ratio of the concentration of any one of the metals Ca, Na, K, Cr, Ni, or Al to the concentration of any one of the ions bromide ion, bromite ion, bromate ion, chloride ion, or chlorate ion is 1 or more (1x10 8 is as follows: Item 2. The semiconductor processing solution according to item 1, further comprising hypobromite ions. Item 3. The semiconductor processing solution according to item 1 or 2, wherein the metals are Ca, Na, and K. Item 4 The semiconductor processing solution, At least one ion selected from the group consisting of bromide ions, bromite ions, and bromate ions; At least one metal selected from the group consisting of Ca, Na, and K; Item 2. The semiconductor processing solution according to item 1, comprising hypobromite ions. Item 5. The semiconductor processing solution according to item 3 or 4, wherein the pH of the semiconductor processing solution is 10.0 or more and 13.0 or less. Item 6: The semiconductor processing solution contains bromate ions, The ratio of the concentration of bromate ions to the total concentration of Ca, Na, and K is 1 or more (1x10 8 Item 5. The semiconductor processing solution according to item 3 or 4, which is as follows: Item 7: The semiconductor processing solution contains at least one ion selected from the group consisting of bromide ions, bromite ions, and bromate ions; The ratio of the concentration of bromide ions, bromite ions, or bromate ions to the total concentration of Cr, Ni, and Al is 1 or more and 1x10 8 Item 5. The semiconductor processing solution according to item 3 or 4, which is as follows: Item 8 In the semiconductor processing solution, Chloride concentration for one of the metals Ca, Na, K, Cr, Ni, or Al The ratio of the concentration of either the chlorine ion or the chlorate ion is 1 or more x 10 8 is as follows: Item 2. The semiconductor processing solution according to item 1, further comprising hypochlorite ions. Item 9 The semiconductor processing solution comprises: At least one ion selected from the group consisting of chloride ions and chlorate ions; At least one metal selected from the group consisting of Ca, Na, and K; Item 2. The semiconductor processing solution according to item 1, comprising hypochlorite ions. Item 10. The semiconductor processing solution according to item 8 or 9, wherein the pH of the semiconductor processing solution is 10.0 or more and 13.0 or less. Section 11 The semiconductor processing solution contains chlorate ions, The ratio of the chlorate ion concentration to the total concentration of Ca, Na, and K is 1 or more (1x10 8 Item 10. The semiconductor processing solution according to item 8 or 9, which is as follows: Item 12: The semiconductor processing solution contains chloride ions, The ratio of chloride ion concentration to the total concentration of Cr, Ni and Al is 1 or more x 10 8 Item 10. The semiconductor processing solution according to item 8 or 9, which is as follows: Section 13 In the semiconductor processing solution, The ratio of the concentration of any one of the metals Ca, Na, K, Cr, Ni, or Al to the concentration of any one of the ions, iodate ion, iodide ion, or triiodide ion, is 1 or more and 1x10 8 is as follows: Item 2. The semiconductor processing solution according to item 1, further comprising periodate ions. Item 14 The semiconductor processing solution comprises: at least one ion selected from the group consisting of iodate ion, iodide ion, and triiodide ion; At least one metal selected from the group consisting of Ca, Na, and K; Item 2. The semiconductor processing solution according to item 1, comprising periodate ions. Item 15. The semiconductor processing solution according to item 13 or 14, wherein the pH of the semiconductor processing solution is 8.5 or more and 11.0 or less. Item 16 The semiconductor processing solution contains iodate ions, The ratio of the concentration of iodate ions to the total concentration of Ca, Na, and K is 1 or more and 1x10 8 Item 16. The semiconductor processing solution according to item 14 or 15, which is as follows: Item 17 The semiconductor processing liquid contains iodide ions, The ratio of the concentration of iodide ions to the total concentration of Cr, Ni, and Al is 1 or more and 1x10 8Item 16. The semiconductor processing solution according to item 14 or 15, which is as follows: Effect of the Invention

[0009] According to the present invention, by adding a certain type of metal and a certain type of ion, preferably at a specific concentration or concentration ratio, it is possible to provide a semiconductor processing liquid that has excellent smoothness for a treated area of ​​a transition metal-containing material and can provide a stable etching rate. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an outline of equipment used in an etching process in a method for manufacturing semiconductor devices. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (Semiconductor processing fluid) The semiconductor processing solution of the present embodiment is characterized by containing a target mixture described below. The semiconductor processing solution of the present invention is also referred to as a processing solution. The target mixture is a mixture in which a specific ion and a specific metal are present. The specific ion is an ion including at least one ion selected from the group consisting of bromide ion, bromite ion, bromate ion, chloride ion, chlorate ion, iodate ion, iodide ion, and triiodide ion, and a halogen oxygen acid ion described below. The specific metal is at least one metal selected from the group consisting of Ca, Na, K, Cr, Ni, and Al.

[0012] (Subject to processing) By using the treatment solution of this embodiment, the smoothness of the substrate surface and the stability of the etching rate (also referred to simply as "stability" in this specification) can be maintained, although the mechanism is not clear. The smoothness and the stability of the etching rate are believed to be due to the difference in the surface oxidation state of the transition metal-containing material on the wafer. The semiconductor wafer preferably contains at least one transition metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W, and Ru, Mo, and W are more preferable. It is believed that by using the treatment solution of this embodiment, the target mixture is adsorbed onto the surface of the transition metal-containing material, and the oxidation state is adjusted, thereby maintaining the smoothness of the substrate surface and the stability of the etching rate.

[0013] The specific metals are usually substances contained as impurities in semiconductor processing solutions. If particles of these metals remain on fine metal wiring, they may cause short circuits and have a significant impact on semiconductor elements. For this reason, it has been thought that the smaller the amount of metal elements in the processing solution, the better. However, JP 2019-142788 A and JP 2017-169832 A show that the amount of metal in the processing solution and the amount of metal on the wafer do not necessarily correlate. For this reason, it is thought that adding a small amount of metal is unlikely to cause effects such as short circuits caused by metal particles.

[0014] (Halogen oxygen acid ion) The treatment solution of this embodiment contains at least one halogen oxygen acid ion selected from the group consisting of hypobromite ion, hypochlorite ion, and periodate ion. The halogen oxygen acid ion functions as an oxidizing agent. The concentration of the halogen oxygen acid ion is not particularly limited as long as it does not deviate from the object of the present invention, but is preferably 50 ppm by mass or more and 35.0% by mass or less. When hypobromite ions or hypochlorite ions are selected as the halogen oxygen acid ions contained in the treatment solution of this embodiment, there are no particular limitations, but from the viewpoint of being able to dissolve transition metals, the content is preferably from 50 mass ppm to 5.0 mass % relative to the total mass of the treatment solution, more preferably from 500 mass ppm to 2.0 mass %, and even more preferably from 500 mass ppm to 5,000 mass ppm. When periodate ions are selected as the halogen oxygen acid ions contained in the treatment liquid of this embodiment, there is no particular limitation, but orthoperiodate ions or metaperiodate ions are preferred because they can dissolve transition metals. In addition, salts of orthoperiodate and metaperiodate may be used because they are ionized when dissolved in water. In particular, orthoperiodate ions are more preferred because they do not contain Na and have a stable composition. In view of the solubility of the treatment liquid, the content of periodate ions is preferably from 0.5% by mass to 35.0% by mass, and more preferably from 2.0% by mass to 8.0% by mass, based on the total mass of the treatment liquid. The halogen oxygen acid ion contained in the treatment solution of this embodiment may be of one type or two or more types. The inclusion of multiple types may stabilize the etching rate and improve the stability during reuse. For example, when the first type of halogen oxygen acid ion contains hypobromite ion, bromide ion is generated as consumption by oxidation or decomposition by disproportionation progresses. A decrease in the concentration of halogen oxygen acid ions causes a decrease in the etching rate. However, if the treatment solution contains hypochlorite ions as the second type of halogen oxygen acid ions, the generated bromide ions can be oxidized and converted to hypobromite ions, which makes it easier to stabilize the etching rate. For the above reasons, when hypobromite ions are contained in the treatment liquid of the present embodiment, it is preferable that hypochlorite ions coexist. The concentration of hypochlorite ions is not limited as long as it does not deviate from the spirit of the present invention, but is preferably 50 mass ppm or more and 5 mass % or less. If the concentration of hypochlorite ions is less than 50 mass ppm, for example, Br -cannot be efficiently oxidized, and the etching rate of ruthenium, etc. is reduced. On the other hand, if the amount of hypochlorite ions added is more than 5 mass%, the stability of hypochlorite ions is reduced, and the decomposition of hypobromite ions due to the reaction between hypochlorite ions and hypobromite ions is promoted, which is not appropriate. The concentration of hypochlorite ions is preferably 50 mass ppm or more and 5 mass % or less, more preferably 500 mass ppm or more and 2 mass %, and even more preferably 500 mass ppm or more and 5000 mass ppm or less.

[0015] (specific ions) As described above, the treatment liquid of this embodiment contains a target mixture. The target mixture also contains specific ions. The specific ions contained in the treatment liquid of this embodiment include at least one ion selected from the group consisting of bromide ions, bromite ions, bromate ions, chloride ions, chlorate ions, iodate ions, iodide ions, and triiodide ions, and halogen oxygen acid ions. The halogen oxygen acid ions are at least one halogen oxygen acid ions selected from the group consisting of hypobromite ions, hypochlorite ions, and periodate ions. Bromide ions can be added to the treatment liquid by, for example, bromine gas, hydrogen bromide, or a bromine salt, and the content can be adjusted by the weight of bromine gas, hydrogen bromide, or a bromine salt added to the treatment liquid. Bromite ions can be contained in the treatment solution, for example, by bromous acid or bromite salts. Bromite salts may be any salts as long as the cation serving as a counter to the bromite ions does not react with halogen oxygen acid ions or does not impair the present invention even if it does react, and examples of such salts include those listed below. The content can be adjusted by the weight of bromous acid or bromite salts added to the treatment solution. Bromate ions can be added to the treatment solution by, for example, bromic acid or a bromate salt, and the content can be adjusted by the weight of bromic acid or a bromate salt added to the treatment solution. The chloride ions can be added to the treatment liquid by, for example, chlorine gas, hydrogen chloride, or a chlorine salt, and the content can be adjusted by the weight of the chlorine gas, hydrogen chloride, or a chlorine salt added to the treatment liquid. The chlorate ions can be contained in the treatment liquid by, for example, chloric acid or a chlorate salt, and the content can be adjusted by the weight of chloric acid or a chlorate salt added to the treatment liquid. Iodate ions can be contained in the treatment liquid, for example, by an iodate salt, and the content can be adjusted by the weight of the iodate salt added to the treatment liquid. Iodide ions can be contained in the treatment liquid by, for example, iodine, iodine gas, hydrogen iodide, or iodine salts, and the content can be adjusted by the weight of iodine, iodine gas, hydrogen iodide, or iodine salts added to the treatment liquid. Triiodide ions can be contained in the processing solution, for example, in the form of a triiodide salt, and the content can be adjusted by the weight of the triiodide salt added to the processing solution.

[0016] A combination of the halogen oxygen acid ion and a specific ion contained in the treatment liquid of this embodiment There are several possible ions, but there is a specific ion that is preferred for each halogen oxygen acid ion. By selecting a specific ion that is preferred for the halogen oxygen acid ion, the storage stability of the treatment liquid is further improved. This is believed to be because the disproportionation reaction of the halogen oxygen acid ion is suppressed. The specific ion selected at this time may be one type or two or more types. When two or more types are selected, the total concentration of the specific ions is preferably 0.01 mass ppt to 2 mass%, preferably 1 mass ppb to 1 mass%, and more preferably 10 mass ppb to 0.1 mass%, based on the total mass of the treatment liquid.

[0017] When hypobromite is selected as the halogen oxygen acid ion, preferred specific ions are bromate, bromite, bromide, chlorate, chloride, or iodate, and more preferably bromate, bromide, chloride, or chlorate.

[0018] When hypochlorite is selected as the halogen oxygen acid ion, preferred specific ions are chlorate, chloride, bromate, bromite, or iodate, more preferably chlorate or chloride.

[0019] When periodate is selected as the halogen oxygen acid ion, preferred specific ions are iodate, iodide, triiodide, bromide, or chloride, more preferably iodate, iodide, or triiodide.

[0020] In addition, even when two or more kinds of halogen oxygen acid ions are selected, there are some specific ions that are preferred as the specific ions to be selected. When hypochlorite ion and hypobromite ion are selected as the halogen oxygen acid ions, the preferred specific ions are bromate ion, bromite ion, bromide ion, chlorate ion, chloride ion, or iodate ion, and more preferably bromate ion, bromide ion, chloride ion, or chlorate ion.

[0021] When a salt is selected as a method for incorporating a specific ion, the counter cation may be any salt as long as it does not react with the halogen oxygen acid ion or does not interfere with the present invention even if it does react. Examples of chloride ions include, but are not limited to, lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, ammonium chloride, and onium chloride. The onium chloride referred to here is a compound formed from an onium ion and a chloride ion. The onium ion is a polyatomic cation compound formed by adding an excess proton (hydrogen cation) to a monoatomic anion. Specifically, the cations include imidazolium ion, pyrrolidinium ion, pyridinium ion, piperidinium ion, ammonium ion, phosphonium ion, fluoronium ion, chloronium ion, bromonium ion, iodonium ion, oxonium ion, sulfonium ion, selenonium ion, telluronium ion, arsonium ion, stibonium ion, and bismuthonium ion. As the salt, a salt formed with an onium ion is preferred, and a compound containing a hydrogen ion is more preferred, since the amount of metal in the treatment liquid is not changed. In order to provide a stable etching rate for the treatment liquid, the content of the specific ion is preferably 0.01 mass ppt to 2 mass %, more preferably 1 mass ppb to 1 mass %, and more preferably 10 mass ppb to 0.1 mass %, based on the total mass of the treatment liquid. This concentration range can be applied to any of the specific ions described above.

[0022] The specific ions are all anions, and counter cations are present in the treatment liquid. Examples of cations include hydrogen cations (H + ), tetraalkylammonium cations (e.g., tetramethylammonium cation (TMA + ), tetraethylammonium cation (TEA + ), Ethyltrimethylammonium cation (ETMA + ), or tetrabutylammonium cation (TBA+ )) or ammonium ion (NH4 + ) is preferred, and hydrogen cation (H + ), or tetramethylammonium cation (TMA + ) is more preferred.

[0023] (certain metals) As described above, the treatment liquid of this embodiment contains the target mixture. The target mixture also contains a specific metal together with specific ions. The specific metal is at least one selected from the group consisting of Ca, Na, K, Cr, Ni, and Al. Although the mechanism is unclear, it is believed that the target mixture in the form of cations is adsorbed on the surface of the transition metal-containing material, and the oxidation state is uniformized, which is considered to be effective for surface smoothness in etching of transition metals. Among these metals, Ca, Na, or K, which have a high ionization tendency, are preferably selected. Even when Cr, Ni, or Al is contained in the treatment liquid of this embodiment, the effect on surface smoothness can be obtained in the same way as when Ca, Na, or K is contained, but when Ca, Na, or K, which have a high ionization tendency, are contained, the effect is greater. In order to obtain excellent smoothness of the treatment liquid, the content of the specific metal is from 0.01 ppt by mass to 200 ppt by mass, preferably from 0.01 ppt by mass to 100 ppt by mass, and more preferably from 0.01 ppt by mass to 50 ppt by mass, relative to the total mass of the treatment liquid. Among the above metals, the concentrations of all the metals Na, K, and Ca are preferably 0.01 mass ppt or more and 200 mass ppt or less. Furthermore, among the above metals, the total concentration of all the metals Na, K, and Ca is 0.01 mass ppt or more and 600 mass ppt or less, preferably 0.01 mass ppt or more and 300 mass ppt or less, and more preferably 0.01 mass ppt or more and 150 mass ppt or less, relative to the total mass of the treatment liquid. Furthermore, among the above metals, the total concentration of all metals, Cr, Ni, and Al, relative to the total mass of the treatment solution is from 0.01 ppt by mass to 600 ppt by mass, preferably from 0.01 ppt by mass to 300 ppt by mass, and more preferably from 0.01 ppt by mass to 150 ppt by mass. In addition, in order to ensure a stable etching rate of the treatment solution, the concentration ratio of the specific ion to each specific metal is set to 1 or more and 1x10 8 The following is preferred: The treatment liquid of the present embodiment may contain Fe, Zn, or Cu in addition to the specific metals described above. When Fe, Zn, or Cu is contained, the content of each of these metals is from 0.01 to 200 ppt by mass, preferably from 0.01 to 100 ppt by mass, and more preferably from 0.01 to 50 ppt by mass, relative to the total mass of the treatment liquid.

[0024] (A combination of a specific ion and a specific metal) The treatment liquid shown in the specific example below contains at least one selected from the group consisting of Ca, Na, K, Cr, Ni, and Al. In the treatment solution of the first specific example of this embodiment, the ratio of the concentration of any one of bromide ions, bromite ions, bromate ions, chloride ions, and chlorate ions to the concentration of any one of metals Ca, Na, K, Cr, Ni, and Al is 1 or more and 1x10 8 The upper limit of the concentration ratio is preferably 2.4×10 7 Preferably, the concentration is 1×10 5 It is more preferable that: In addition, the ratio of the ion concentration of any one of bromide ions, bromite ions, and bromate ions to the total concentration of Ca, Na, and K in the treatment solution of the second specific example of this embodiment is 1 or more and 1x10 8 The upper limit of the concentration ratio is preferably 2.4×10 7 Preferably, the concentration is 1×10 5 In this specific example, it is preferable that the treatment liquid contains all of Ca, Na, and K. In the first and second two specific examples, the pH of the semiconductor processing solution is preferably 10.0 or more and 13.0 or less. The treatment solution according to the third specific example of this embodiment contains bromate ions, and the ratio of the concentration of bromate ions to the total concentration of Ca, Na, and K is 1 or more and 1×10 8 The upper limit of the concentration ratio is preferably 9.7×10 6 Preferably, the concentration is 1×10 5 In this specific example, it is preferable that the treatment liquid contains all of Ca, Na, and K. The fourth treatment liquid of the present embodiment contains at least one ion selected from the group consisting of bromide ions, bromite ions, and bromate ions, The ratio of the concentration of bromide ions, bromite ions, or bromate ions to the total concentration of Cr, Ni, and Al is 1 or more and 1x10 8 The upper limit of the concentration ratio is preferably 6.0×10 5 It is preferable that the ratio is 5.0×10 5 In this specific example, it is more preferable that the treatment liquid contains all of Cr, Ni and Al. In addition, in the treatment solution of the fifth specific example of this embodiment, the ratio of the ion concentration of any one of chloride ions or chlorate ions to the concentration of any one of metals Ca, Na, K, Cr, Ni, and Al is 1 or more and 1×10 8 The upper limit of the concentration ratio is preferably 2.3×10 6 Preferably, the concentration is 1×10 5 It is more preferable that: In addition, the treatment liquid of the sixth specific example of this embodiment preferably contains at least one type of ion selected from the group consisting of chloride ions and chlorate ions, at least one type of metal selected from the group consisting of Ca, Na, and K, and hypochlorite ions. In addition, the ratio of the ion concentration of any one of chloride ions and chlorate ions to the total concentration of Ca, Na, and K in the treatment solution of the seventh specific example of this embodiment is 1 or more and 1x10 8The upper limit of the concentration ratio is preferably 2.3×10 6 Preferably, the concentration is 1×10 5 In this specific example, it is preferable that the treatment liquid contains all of Ca, Na, and K. The pH of the treatment liquid in the sixth and seventh specific examples is preferably 10.0 or more and 13.0 or less. The treatment solution according to the eighth specific example of this embodiment contains chlorate ions, and the ratio of the concentration of chlorate ions to the total concentration of Ca, Na, and K is 1 or more and 1×10 8 The upper limit of the concentration ratio is preferably 2.6×10 7 Preferably, the concentration is 1×10 5 In this specific example, it is preferable that the treatment liquid contains all of Ca, Na, and K. The treatment liquid according to the ninth specific example of this embodiment contains chloride ions, and the ratio of the concentration of chloride ions to the total concentration of Cr, Ni, and Al is 1 or more and 1×10 8 The upper limit of the concentration ratio is preferably 6.0×10 5 Preferably, it is 5.5×10 5 In this specific example, it is more preferable that the treatment liquid contains all of Cr, Ni and Al. In addition, in the treatment liquid according to the tenth specific example of the present embodiment, the ratio of the concentration of any one of iodate ions, iodide ions, and triiodide ions to the concentration of any one of metals, Ca, Na, K, Cr, Ni, and Al, is 1 or more and 1x10 8 The upper limit of the concentration ratio is 1.8×10 or less, and preferably contains periodate ions. 7 Preferably, the concentration is 1×10 5 It is more preferable that: In addition, the treatment liquid of an eleventh specific example of this embodiment preferably contains at least one type of ion selected from the group consisting of iodate ions, iodide ions, and triiodide ions, at least one type of metal selected from the group consisting of Ca, Na, and K, and periodate ions. In the treatment liquid of the twelfth specific example, the concentration of any one of iodate ions, iodide ions, and triiodide ions is preferably 1 ppb by mass or more and 1% by mass or less. The pH of the treatment liquid in the tenth and eleventh specific examples is preferably 8.5 or more and 11.0 or less. In the treatment solutions of the tenth and eleventh specific examples, the ratio of the concentration of iodate ions to the total concentration of Ca, Na, and K is 1 or more and 1x10 8 The upper limit of the concentration ratio is preferably 1.9×10 7 Preferably, the concentration is 1×10 5 It is more preferable that: The treatment solution according to the thirteenth specific example of the present embodiment contains iodide ions, and the ratio of the concentration of the iodide ions to the total concentration of Cr, Ni, and Al is 1 or more and 1×10 8 The upper limit of the concentration ratio is preferably 5.5×10 5 It is preferable that the ratio is 5.0×10 5 In this specific example, it is more preferable that the treatment liquid contains all of Cr, Ni and Al.

[0025] (pH) The pH of the treatment liquid of this embodiment is preferably 8.5 to 13.0. Within this range, there is a preferred pH range depending on the halogen oxygen acid ion selected. Specifically, this is as explained in each of the above embodiments. The reason for the preferred pH range is that if the pH is too low, the storage stability of the halogen oxygen acid ion deteriorates, and if the pH is too high, the etching rate for transition metals slows down. The storage stability is an evaluation of the change in concentration of the halogen oxygen acid ion when the treatment liquid is stored for a long period of time. When periodate ions are contained as halogen oxygen acid ions in the treatment liquid of this embodiment, the pH is preferably 8.5 to 11.0, and more preferably 9.0 to 10.0, from the viewpoints of dissolving ability, smoothness, storage stability, and etching rate stability. When at least one of hypobromite ions and hypochlorite ions is selected as the halogen oxygen acid ions contained in the treatment liquid of this embodiment, the pH is preferably 10.0 to 13.0, and more preferably 12.0 to 12.6, from the viewpoints of dissolving ability, smoothness, storage stability, and etching rate stability.

[0026] (others) The treatment liquid of this embodiment may contain other additives that have been used in semiconductor treatment liquids in the past, as long as the purpose of the present invention is not impaired. For example, as other additives, acids, metal anticorrosives, water-soluble organic solvents, fluorine compounds, reducing agents, complexing agents, chelating agents, surfactants, defoamers, pH adjusters, stabilizers, etc. may be added. These additives may be added alone or in combination.

[0027] As a pH adjuster, an acid or an alkali can be added to the treatment liquid of this embodiment. As the alkali, it is preferable to use an organic alkali since it does not contain metal ions that are problematic in semiconductor manufacturing. Among them, the organic alkali is preferably tetraalkylammonium hydroxide, and more preferably tetramethylammonium hydroxide, since it has a large number of hydroxide ions per unit weight and high purity products are easily available.

[0028] The water contained in the treatment solution of this embodiment is preferably water from which metal ions, organic impurities, particle particles, etc. have been removed by distillation, ion exchange treatment, filter treatment, various adsorption treatments, etc., and is particularly preferably pure water or ultrapure water. Such water can be obtained by a known method that is widely used in semiconductor manufacturing.

[0029] The temperature when etching ruthenium using the semiconductor processing solution of this embodiment is not particularly limited, but may be determined taking into consideration the etching rate of ruthenium, the amount of RuO4 gas generated, etc. When the processing temperature is high, the amount of RuO4 gas increases and the stability of the halogen oxygen acid ion also decreases. On the other hand, the lower the temperature, the lower the etching rate tends to be. For these reasons, The temperature for etching ruthenium is preferably 10°C to 90°C, more preferably 15°C to 60°C, and most preferably 25°C to 45°C.

[0030] The treatment liquid of this embodiment is preferably stored at low temperature and / or protected from light. By storing at low temperature and / or protected from light, it is expected that the decomposition of the oxidizing agent in the treatment liquid can be suppressed. Furthermore, the stability of the treatment liquid can be maintained by storing the treatment liquid in a container filled with an inert gas and preventing the inclusion of carbon dioxide. In addition, the inner surface of the container, i.e., the surface that comes into contact with the treatment liquid, is preferably made of glass or an organic polymer material. If the inner surface of the container is made of glass or an organic polymer material, the inclusion of impurities such as metals, metal oxides, and organic substances can be further reduced.

[0031] (Filter lubricant) The treatment liquid of this embodiment may contain onium ions as a filtration lubricant. If the surface tension of the filtration lubricant is low, it may be removed during the filtration process, so the surface tension of the filtration lubricant is preferably 60 mN / m or more and 75 mN / m or less. By interacting with the metal surface of the semiconductor wafer, it is possible to suppress roughness of the metal surface. In addition, when ruthenium is contained in the semiconductor wafer, RuO4 generated during etching of ruthenium is easily removed. - or RuO4 2- By interacting with the above, it is possible to suppress the generation of RuO4 gas and the accompanying RuO2 particles. Thus, the onium ions contained in the filtration lubricant used in this embodiment play various roles, but in order to maintain these effects at a high level, the surface tension of the filtration lubricant is the key. That is, if the surface tension of the filtration lubricant is less than 60 mN / m, the onium ions contained in the filtration lubricant are easily removed by the filtration process, making it difficult to maintain the good surface smoothness and RuO4 gas suppression effect described above. One method for increasing the surface tension is to add a large amount of salt, but when the filtration lubricant used in this embodiment contains an oxidizing agent described later, the stability of the oxidizing agent may decrease due to the reaction between the salt and the oxidizing agent, or etching may be inhibited due to a high concentration of salt. For these reasons, the surface tension is preferably 75 mN / m or less.

[0032] Here, the filtration step will be described. In the manufacture of semiconductor wafers, the adhesion of particles to the wafers leads to a decrease in yield, so the treatment liquid is filtered in order to remove particles from the treatment liquid. In the case of cutting-edge semiconductor wafers, the wiring width is very fine, ranging from several nm to several tens of nm, and therefore the pore size of the filter used in the filtration step is required to be of the same size. However, the smaller the pore size of the filter, the easier it is for the onium salt or onium ion to be adsorbed and removed. This reduces the onium ion concentration in the treatment liquid, impairing the function of the treatment liquid described above. However, such a decrease in the concentration of onium ions can be avoided by controlling the surface tension of the filtration lubricant. Specifically, the surface tension of water is around 73 mN / m at 25°C, and by approaching this value, it is possible to suppress the adsorption of onium salts or onium ions to the filter. That is, by controlling the surface tension of the filtration lubricant to 60 mN / m or more and 75 mN / m or less, the adsorption of onium salts or onium ions to the filter can be suppressed, and the filtration lubricant can be used as a processing liquid without losing its function. For these reasons, the surface tension is 60 mN / m or more and 75 mN / m or less, preferably 68 mN / m or more and 75 mN / m or less, and most preferably 71 mN / m or more and 73 mN / m or less. Here, the surface tension in this specification is a value at 25°C.

[0033] (onium ion) The surface tension is affected by the onium ion used as the filtration lubricant in this embodiment. Therefore, by appropriately selecting the type and concentration of the onium ion, it is possible to maintain the surface tension within an appropriate range. In order to maintain the surface tension within a preferred range, the following formula (1 It is preferable to select one or more selected from the group consisting of onium ions having the structures shown by (1) to (6). [ka] [ka] [ka] [ka] [ka] [ka] (In formulas (1) to (6), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 are independently an alkyl group having 2 to 9 carbon atoms, an aryl group, group, an aralkyl group having an alkyl group having 1 to 9 carbon atoms, or an aryl group. In the aryl group in the aralkyl group and in the ring of the aryl group, at least one hydrogen atom may be replaced by fluorine, chlorine, an alkyl group having 1 to 9 carbon atoms, an alkenyl group having 2 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, or an alkenyloxy group having 2 to 9 carbon atoms, and in these groups, at least one hydrogen atom may be replaced by fluorine, chlorine, bromine, or iodine. Examples of counter anions to the onium ions include fluoride ion, chloride ion, bromide ion, iodide ion, hydroxide ion, nitrate ion, phosphate ion, sulfate ion, hydrogen sulfate ion, methanesulfate ion, perchlorate ion, chlorate ion, chlorite ion, hypochlorite ion, orthoperiodate ion, metaperiodate ion, iodate ion, iodite ion, hypoiodite ion, acetate ion, carbonate ion, hydrogen carbonate ion, fluoroborate ion, and trifluoroacetate ion. A is an ammonium ion or a phosphonium ion. Z is an aromatic group or alicyclic group which may contain nitrogen, sulfur or oxygen atoms, and in the aromatic group or alicyclic group, carbon or nitrogen may have chlorine, bromine, fluorine, iodine, at least one alkyl group having 1 to 9 carbon atoms, at least one alkenyloxy group having 2 to 9 carbon atoms, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. R is chlorine, bromine, fluorine, iodine, an alkyl group having 1 to 9 carbon atoms, an allyl group, an aromatic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms, or an alicyclic group which may be substituted with at least one alkyl group having 1 to 9 carbon atoms. n is an integer of 1 or 2 and indicates the number of R. When n is 2, R may be the same or different and may form a ring. a is an integer from 1 to 10.

[0034] The longer the chain of the hydrocarbon group represented by R in the formula, the higher the hydrophobicity. Therefore, the longer the chain of the onium ion with the hydrocarbon group, the lower the surface tension of the filtration lubricant. On the other hand, if the hydrocarbon chain is too short, the effect of the onium ion, which is the improvement of surface smoothness and the suppression effect of RuO4 gas, is limited. For this reason, the carbon number of the hydrocarbon group is preferably within the above-mentioned range.

[0035] The concentration of onium ions in the treatment solution of this embodiment is preferably 1 ppm by mass or more and 10,000 ppm by mass or less. If the amount of onium ions added is too small, when the solution is used as a treatment solution for ruthenium semiconductors, RuO4 -etc., the interaction with the metal oxide, etc. is weakened, and the RuO4 gas suppression effect is reduced, and the amount of onium ions attached to the metal surface during etching is insufficient, so that the surface smoothness tends to decrease. On the other hand, if the amount added is too large, the amount of onium ions adsorbed to the metal surface becomes excessive, and the etching rate decreases. In addition, in the semiconductor processing solution of this embodiment, the halogen oxygen acid ions react with the onium ions, which may cause a decrease in the concentration of the halogen oxygen acid ions. Therefore, the processing solution of this embodiment preferably contains onium ions at 1 mass ppm or more and 10,000 mass ppm or less, more preferably at 10 mass ppm or more and 5,000 mass ppm or less, and even more preferably at 50 mass ppm or more and 2000 mass ppm or less. When onium ions are added, only one type may be added, or two or more types may be added in combination. Even when two or more types of onium ions are included, the generation of RuO4 gas can be effectively suppressed as long as the total concentration of the onium ions is within the above concentration range.

[0036] Examples of such onium ions include chlorocholine ion, trans-2-butene 1,4-bis(triphenylphosphonium ion), 1-hexyl-3-methylimidazolium ion, allyltriphenylphosphonium ion, tetraphenylphosphonium ion, benzyltriphenylphosphonium ion, and methyltriphenylphosphonium ion. ion, (2-carboxyethyl)triphenylphosphonium ion, (3-carboxypropyl)triphenylphosphonium ion, (4-carboxybutyl)triphenylphosphonium ion, (5-carboxypentyl)triphenylphosphonium ion, cinnamyltriphenylphosphonium ion, (2-hydroxybenzyl)triphenylphosphonium ion, (1-naphthylmethyl)triphenylphosphonium ion, butyltriphenylphosphonium ion, (tert-butoxycarbonylmethyl)triphenylphosphonium ion, allyltriphenylphosphonium ion, (3-methoxybenzyl)triphenylphosphonium ion, (methoxymethyl)triphenylphosphonium ion, (1-ethoxy-1-oxopropane-2- (yl)triphenylphosphonium ion, (3,4-dimethoxybenzyl)triphenylphosphonium ion, methoxycarbonylmethyl(triphenyl)phosphonium ion, (2,4-dichlorobenzyl)triphenylphosphonium ion, (2-hydroxy-5-methylphenyl)triphenylphosphonium ion, (4-chlorobenzyl)triphenylphosphonium ion, (3-chloro-2-hydroxypropyl)trimethylammonium ion, methacroylcholine ion, benzoylcholine ion, benzyldimethylphenylammonium ion, (2-methoxyethoxymethyl)triethylammonium ion, carbamylcholine ion, 1,1'-difluoro-2,2'-bipyridinium bis(tetrafluoroborate), benzylto tributylammonium ion, trimethylphenylammonium ion, 5-azoniaspiro[4.4]nonane ion, tributylmethylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrabutylphosphonium ion, diallyldimethylammonium ion, 1,1-dimethylpiperidinium ion, (2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium hydroxide, 3-(trifluoromethyl)phenyltrimethylammonium ion, 1,1'-(decane- 1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diion, (3-bromopropyl)trimethylammonium ion, vinylbenzyltrimethylammonium ion Allylammonium ion, allyltrimethylammonium ion, trimethylvinylammonium ion, choline ion, β-methylcholine ion, and triphenylsulfonyl and the like, and preferably at least one selected from the group consisting of benzyldimethylphenylammonium ion, 1-ethoxy-1-oxopropan-2-yl)triphenylphosphonium ion, 1,1'-(decane-1,10-diyl)bis[4-aza-1-azoniabicyclo[2.2.2]octane]diion, butyltriphenylphosphonium ion, (2-carboxyethyl)triphenylphosphonium ion, (3-carboxypropyl)triphenylphosphonium ion, (4-carboxybutyl)triphenylphosphonium ion, allyltriphenylphosphonium ion, tetraphenylphosphonium ion, and benzyltriphenylphosphonium ion.

[0037] As mentioned above, the effects of onium ions include suppressing surface roughness during etching and suppressing RuO4 gas (when etching ruthenium), but in addition to this, they also have the effect of increasing the number of times they can be reused when used as a semiconductor processing solution. From the viewpoint of cost reduction, it is common for semiconductor wafer manufacturing plants to circulate and reuse used processing solutions. In this case, for example, during etching, metals dissolve into the processing solution, so the composition of the processing solution differs before and after use. Taking the example of etching ruthenium with halogen oxygen acid ions such as hypobromite ions, ruthenium becomes RuO4 under alkaline conditions. - In this case, this RuO4 - Or RuO4 - The RuO4 produced by the change 2-When hypobromite ions react with RuO4, the concentration of hypobromite ions, which are effective chemical species for etching, decreases. Therefore, the more times the treatment solution is reused and the longer the reuse time, the lower the etching rate becomes.

[0038] However, by adding onium ions to the treatment solution of this embodiment, the stability during reuse may be improved. - Etc. are demons By reacting with ruthenium ions, RuO4 - It is possible to suppress the reaction of the ammonium ion with halogen oxygen acid ions such as hypobromite ions. As an onium ion that can be used for such a purpose, a phosphonium ion is preferable. In the case of ammonium ions, there is a concern that amines will be generated by reaction with halogen oxygen acid ions such as hypobromite ions, and these amines may decompose halogen oxygen acid ions such as hypobromite ions. In addition, phosphonium ions generally have a larger molecular size than ammonium ions, and RuO4 generated by dissolution may be easily dissolved. - Since it easily forms an ion pair with RuO4 - By binding RuO4 - In addition, the effect of suppressing the reaction between the halogen atom and a halogen oxygen acid ion such as hypobromite ion can be obtained.

[0039] Examples of such onium ions include an allyltriphenylphosphonium ion, a tetraphenylphosphonium ion, a trans-2-butene-1,4-bis(triphenylphosphonium ion), a benzyltriphenylphosphonium ion, a tetrabutylphosphonium ion, a tributylhexylphosphonium ion, a heptyltriphenylphosphonium ion, a cyclopropyltriphenylphosphonium ion, a (bromomethyl)triphenylphosphonium ion, and a (chloromethyl)triphenylphosphonium ion.

[0040] (Semiconductor wafer etching process) The treatment liquid of this embodiment can be used in an etching process for a semiconductor wafer. The etching process includes a step of contacting a semiconductor wafer with the treatment liquid of this embodiment. The treatment liquid of this embodiment, when containing the above-described filter lubricant, can be preferably used as an etching liquid for semiconductor wafers. The above-described conditions for the filter lubricant can be applied. As an example of the etching process performed using the processing solution of this embodiment, a wet etching process of ruthenium will be described. First, a substrate made of a semiconductor (e.g., Si) is prepared. The prepared substrate is subjected to an oxidation process 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 a predetermined interval. After the via holes are formed, a ruthenium film is formed by thermal CVD. By etching this ruthenium film using the processing solution of this embodiment, it is possible to form a ruthenium wiring having excellent surface smoothness in the via holes while suppressing the generation of RuO4 gas. The metal contained in the semiconductor wafer may be at least one metal selected from Ru, Rh, Ti, Ta, Co, Cr, Hf, Os, Pt, Ni, Mn, Cu, Zr, La, Mo, and W. Among these, ruthenium is not limited to metallic ruthenium, and may contain 70 atomic % or more of ruthenium, and also includes ruthenium alloys, oxides of ruthenium (ruthenium dioxide, ruthenium trioxide, etc.), nitrides, oxynitrides, intermetallic compounds, ionic compounds, complexes, etc.

[0041] The temperature when etching metals such as ruthenium (specific examples will be described later) using the treatment liquid of this embodiment is not particularly limited, but may be determined in consideration of the etching rate of metals such as ruthenium. If the treatment temperature is high, for example, when etching ruthenium, the amount of RuO4 gas increases, and the stability of the halogen oxygen acid also decreases. On the other hand, the etching rate tends to decrease as the temperature decreases. For these reasons, the temperature for etching metals such as ruthenium is preferably 10°C to 90°C, more preferably 15°C to 60°C, and most preferably 25°C to 45°C. When the treatment liquid of this embodiment contains a filtration lubricant, the surface tension at 25°C is preferably 60 mN / m or more and 75 mN / m or less.

[0042] Explaining with reference to FIG. 1, during the manufacture of semiconductor devices, the processing liquid of this embodiment has an opportunity to pass through filters 1 and 2 or 3. When valve 10 in FIG. 1 is closed and valve 9 is opened, the chemical liquid in chemical cabinet 6 passes through filters 1 and 2 by the drive of pump 4. Filtration is performed by passing the chemical liquid through filters 1 and 2. In order to remove as many impurities as possible from the chemical liquid in chemical cabinet 6, the filtration step of passing the chemical liquid through filters 1 and 2 may be performed multiple times. The number of filters through which the chemical liquid is passed in one filtration step can be, for example, one or more, and may be two, three, or four or more. 1 is opened, the chemical liquid in the chemical cabinet 6 is supplied to the etching table 8 by the drive of the pump 4, and the semiconductor wafer is etched. In order to replenish the chemical liquid in the chemical cabinet 6, the chemical liquid in the chemical liquid replenishment unit is passed through the filter 3 by the drive of the pump 5, and replenished into the chemical cabinet 6. The chemical solution described here is the treatment solution of this embodiment, and may be a treatment solution to which the above-mentioned filtration lubricant has been added. In addition to the etching process of the semiconductor wafer, a semiconductor element can also be manufactured by carrying out known steps used in the manufacturing method of a semiconductor element, such as one or more steps selected from a wafer preparation step, an oxide film formation step, a transistor formation step, a wiring formation step, and a CMP step. EXAMPLES

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0044] (Production of trimethylammonium hypochlorite solution) In a 2L glass three-neck flask (Cosmos Bead), 209 g of a 25% by mass aqueous solution of tetramethylammonium hydroxide and 791 g of ultrapure water were mixed to obtain an aqueous solution of 5.2% by mass of tetramethylammonium hydroxide with a CO2 content of 0.5 ppm. The pH at this time was 13.8.

[0045] Next, a rotor (AsOne, total length 30 mm x diameter 8 mm) was placed in a three-neck flask, a thermometer protection tube (Cosmos Bead, bottom-sealed type) and a thermometer were placed in one opening, and a PFA tube (Flon Industries, F-8011-02) connected to a chlorine gas cylinder and a nitrogen gas cylinder in the other opening, with the tip of the tube immersed in the bottom of the solution, and the remaining opening was connected to a gas washing bottle (AsOne, gas washing bottle, model number 2450 / 500) filled with a 5% by mass aqueous solution of sodium hydroxide. Next, nitrogen gas with a carbon dioxide concentration of less than 1 ppm was pumped from the PFA tube at a pressure of 0.289 Pa·m 3 / sec (at 0°C) for 20 minutes to expel carbon dioxide from the gas phase. At this time, the carbon dioxide concentration in the gas phase was 1 ppm or less.

[0046] Then, a magnetic stirrer (AsOne, C-MAG HS10) was placed in the three-port The flask was placed at the bottom of the flask and rotated at 300 rpm for stirring. The outer periphery of the three-neck flask was cooled with ice water while chlorine gas (manufactured by Fujiox Co., Ltd., purity specification 99.4%) was pumped into the flask at 0.059 Pa m 3 / sec (at 0°C) for 180 minutes to obtain a mixed solution of tetramethylammonium hypochlorite (hypochlorite ion; 3.51% by mass, 0.28 mol / L) and tetramethylammonium hydroxide (0.09% by mass, 0.0097 mol / L). The liquid temperature during the reaction was 11°C.

[0047] (Production of processing solution) Solutions containing halogen oxygen acid ions, specific metals, specific ions, ultrapure water, and pH adjusters By mixing the specified amounts, a treatment liquid having the composition shown in Table 1 was obtained.

[0048] (Halogen oxygen acid ions in the treatment solution) When hypochlorite ions are selected as the halogen oxygen acid ions, the tetramethylammonium hypochlorite solution obtained by the above operation is mixed with a solution containing halogen oxygen acid ions. were used at the specified concentrations. When hypobromite ions, or hypobromite ions and hypochlorite ions, were selected as the halogen oxygen acid ions, a predetermined amount of tetramethylammonium bromide (97% by mass, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the tetramethylammonium hypochlorite solution obtained by the above operation to prepare a solution containing halogen oxygen acid ions at a predetermined concentration. When periodate ions were selected as the halogen oxygen acid ions, a solution containing orthoperiodate ions was used at a predetermined concentration as the solution containing halogen oxygen acid ions.

[0049] (Specific ions in the processing solution) As specific ions, chlorate ions, chloride ions, bromate ions, bromite ions, bromide ions, iodate ions, iodide ions, and triiodide ions were added to the treatment solution at the concentrations shown in Table 1. Commercially available sodium chlorate (Wako Pure Chemical Industries), sodium chlorite (Wako Pure Chemical Industries), hydrogen chloride (35% by mass, Kanto Chemical), sodium bromate (Wako Pure Chemical Industries), sodium bromite (Nippon Silica Industry), hydrogen bromide (47% by mass, Tama Chemical Industry), sodium iodate (Wako Pure Chemical Industries), hydrogen iodide (55% by mass, Wako Pure Chemical Industries), and tetrabutylammonium triiodide (Sigma-Aldrich) were added at a predetermined weight to the treatment solution. Sodium chlorate, sodium chlorite, sodium bromate, sodium bromite, sodium iodate, and tetrabutylammonium triiodide were exchanged for tetramethylammonium ions using ion exchange resins. The amount of each ion added was confirmed to be the specified amount by using ion chromatography (Thermo Fisher Scientific).

[0050] (evaluation) Using the produced treatment solution, the surface smoothness of ruthenium and the stability of the etching rate of ruthenium were evaluated by the above-mentioned method.

[0051] (Evaluation of surface smoothness after etching) First, an oxide film was formed on a silicon wafer using a batch-type thermal oxidation furnace, and ruthenium was deposited on the oxide film to a thickness of 1200 Å (±10%) using a sputtering method to obtain a ruthenium film before etching. Next, 40 mL of the treatment solution obtained above was prepared in a fluororesin container with a lid (AsOne, PFA container 94.0 mL). A 10×10 mm ruthenium film piece on which a ruthenium film with a thickness of 1200 Å was deposited was immersed in a chemical solution at 35° C. for 2 minutes to obtain a ruthenium film after etching. The ruthenium surface before and after etching was observed using a field emission scanning electron microscope (JSM-7800F Prime, JEOL Ltd.) to confirm the presence or absence of surface roughness, and was evaluated according to the following criteria. The order of surface roughness was A to D, with A to C being acceptable levels, and D being unacceptable levels. A: No surface roughness is observed. B: Some surface roughness is observed. C: Roughness is observed over the entire surface, but the roughness is shallow. D: Roughness is observed over the entire surface, and the roughness is deep.

[0052] (Evaluation of Etching Rate Stability) The treatment solution obtained above was prepared, and the stability of the etching rate was evaluated. The sheet resistance was measured using a four-point probe resistance meter (Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and converted into a film thickness, which was taken as the ruthenium film thickness before the etching treatment. 40 mL of the treatment solution obtained above was prepared in a fluororesin container with a lid (AsOne Co., Ltd., PFA container 94.0 mL). A 10 x 10 mm ruthenium film piece on which a ruthenium film with a thickness of 1200 Å had been formed was immersed in a chemical solution at 35°C for 2 minutes, and the ruthenium film thickness was measured according to the above-mentioned method, which was taken as the film thickness after the etching treatment. This was taken as the etching rate immediately after the preparation of the treatment solution, and was then measured every week according to the above-mentioned method. The etching rate was evaluated by the etching method. The time during which the obtained etching rate was within ±10% of the etching rate immediately after the preparation of the treatment liquid was defined as the stability of the etching rate, and was evaluated according to the following criteria. Grades A to C are acceptable levels, and grade D is unacceptable. A: 180 days or more B: 120 days or more and 179 days or less C: 60 days or more and 119 days or less D: 59 days or less

[0053] (comprehensive evaluation) Taking into consideration the results of both the evaluation of surface smoothness after etching and the evaluation of etching rate stability obtained above, the treatment liquids were rated according to the following criteria. The effectiveness of the treatment liquids was ranked from A to D, with A to C being acceptable levels and D being unacceptable. A: Surface roughness is rated A and stability is rated A B: Either the surface roughness evaluation or the stability evaluation includes a B, and both evaluations are within the range of A to C. C: Either the surface roughness evaluation or the stability evaluation includes a C, and both evaluations are within the range of A to C. (Acceptable level) D: Either the surface roughness evaluation or the stability evaluation includes a D.

[0054] (Calculation method for hypobromite ion and hypochlorite ion concentration) The concentration of hypobromite ions and hypochlorite ions was measured using an ultraviolet-visible spectrophotometer (UV-2600, manufactured by Shimadzu Corporation). A calibration curve was created using aqueous solutions of hypobromite ions and hypochlorite ions with known concentrations, and the concentrations of hypobromite ions and hypochlorite ions in the semiconductor processing solution were determined. The concentrations of hypobromite ions and hypochlorite ions were determined from the measurement data when the absorption spectrum stabilized after the processing solution was produced.

[0055] <Examples 1 to 61 and Comparative Examples 1 to 12> Tests were carried out for Examples 1 to 61 and Comparative Examples 1 to 12 using the method described above. Tables 1 to 5 show the composition of the treatment liquid and the evaluation results. The "specific ratio" shown in Tables 1 to 4 below is the ratio of the concentration of the specific ion described in the table to the total concentration of Na, K, and Ca contained in the treatment liquid. The "specific ratio" shown in Table 5 below is the ratio of the concentration of the specific ion described in the table to the total concentration of Cr, Ni, and Al contained in the treatment liquid. As shown in Tables 1 to 4, in Comparative Examples 1 to 2, 4 to 5, 7 to 8, and 10 to 11, the addition of chlorite ions resulted in a loss of etching rate stability, and in Comparative Examples 3, 6, 9, and 12, the surface smoothness was lost due to the excessive amount of metal. In contrast, it was confirmed that the treatment liquid of this example satisfies the surface smoothness and etching rate stability by adding a specific metal and a specific ion. In addition, the results showed that the etching rate stability worsened as the concentration of the specific ion increased, and the results showed that the surface smoothness and etching rate stability were more effective when the ratio of the specific metal to the specific ion was within a predetermined range. Table 5 shows the results when the metal species added in Examples 1, 19, 33, and 43 was changed from the total concentration of Na, K, and Ca to the total concentration of Cr, Ni, and Al. As shown in Table 5, the total concentration of Cr, Ni, and Al can provide the same effect as the total concentration of Na, K, and Ca. However, as shown in Examples 1, 19, 33, and 43, selecting the total concentration of Na, K, and Ca has a greater effect on surface roughness due to differences in adsorption caused by ionization tendency. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5]

[0056] <Examples 62 to 65> Similar to the ruthenium film formation method, first, a batch-type thermal oxidation furnace is used to deposit ruthenium on a silicon wafer. An oxide film is formed, and transition metals (W, Mo) are deposited on it to a thickness of 1200 Å (±1 The sheet resistance was measured using a four-probe resistance meter (Loresta GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and converted into film thickness. Using the same treatment liquid as in Examples 1, 19, 33, and 43, and in the same manner as in Examples 1 to 61, the surface smoothness and etching rate stability of the treated area of ​​the transition metal film (W, Mo) obtained by the above method were evaluated. [Table 6] [Explanation of symbols]

[0057] 1 Filter 1 2 Filter 2 3. Filter 3 4 Pump 1 5. Pump 2 6. Chemical Cabinet 7 Chemical refill unit 8 Etching stand 9 Valve 1 10 Valve 2

Claims

1. A semiconductor processing solution used for removing transition metal-containing substances on a substrate, comprising: the semiconductor processing solution contains at least one halogen oxygen acid ion selected from the group consisting of hypobromite ions, hypochlorite ions, and periodate ions; at least one ion selected from the group consisting of bromide ion, bromite ion, bromate ion, chloride ion, chlorate ion, iodate ion, iodide ion, and triiodide ion; A semiconductor processing solution comprising at least one metal selected from the group consisting of Ca, Na, K, Cr, Ni, and Al, and having a concentration of any one of Ca, Na, K, Cr, Ni, and Al of 0.1 ppt by mass or more and 200 ppt by mass or less.

2. In the semiconductor processing solution, The ratio of the concentration of any one of bromide ions, bromite ions, bromate ions, chloride ions, or chlorate ions to the concentration of any one of metals Ca, Na, K, Cr, Ni, or Al is 1 or more and 1x10 ８ is as follows: The semiconductor processing solution according to claim 1 , further comprising hypobromite ions.

3. 3. The semiconductor processing solution according to claim 1, wherein the metals are Ca, Na, and K.

4. The semiconductor processing solution is At least one ion selected from the group consisting of bromide ions, bromite ions, and bromate ions; At least one metal selected from the group consisting of Ca, Na, and K; The semiconductor processing solution according to claim 1 , further comprising hypobromite ions.

5. 5. The semiconductor processing solution according to claim 3, wherein the pH of the semiconductor processing solution is from 10.0 to 13.

0.

6. the semiconductor processing solution contains bromate ions, The ratio of the concentration of bromate ions to the total concentration of Ca, Na, and K is 1 or more x 10 ８ 5. The semiconductor processing solution according to claim 3, wherein:

7. the semiconductor processing solution contains at least one ion selected from the group consisting of bromide ions, bromite ions, and bromate ions, The ratio of the concentration of bromide ions, bromite ions, or bromate ions to the total concentration of Cr, Ni, and Al is 1 or more and 1x10 ８ 5. The semiconductor processing solution according to claim 3, wherein:

8. In the semiconductor processing solution, The ratio of the concentration of any one of chloride ions or chlorate ions to the concentration of any one of metals Ca, Na, K, Cr, Ni, or Al is 1 or more and 1x10 ８ is as follows: The semiconductor processing solution according to claim 1 , further comprising hypochlorite ions.

9. The semiconductor processing solution comprises At least one ion selected from the group consisting of chloride ions and chlorate ions; At least one metal selected from the group consisting of Ca, Na, and K; The semiconductor processing solution according to claim 1 , further comprising hypochlorite ions.

10. 10. The semiconductor processing solution according to claim 8, wherein the pH of the semiconductor processing solution is from 10.0 to 13.

0.

11. The semiconductor processing solution contains chlorate ions, The ratio of the chlorate ion concentration to the total concentration of Ca, Na, and K is 1 or more x 10 ８ 10. The semiconductor processing solution according to claim 8, wherein:

12. The semiconductor processing solution contains chloride ions, The ratio of chloride ion concentration to the total concentration of Cr, Ni and Al is 1 or more and 1x10 ８ 10. The semiconductor processing solution according to claim 8, wherein:

13. In the semiconductor processing solution, The ratio of the concentration of any one of iodate ions, iodide ions, or triiodide ions to the concentration of any one of metals, Ca, Na, K, Cr, Ni, or Al, is 1 or more and 1x10 ８ is as follows: The semiconductor processing solution according to claim 1 , further comprising periodate ions.

14. The semiconductor processing solution comprises at least one ion selected from the group consisting of iodate ion, iodide ion, and triiodide ion; At least one metal selected from the group consisting of Ca, Na, and K; The semiconductor processing solution according to claim 1 , further comprising periodate ions.

15. The semiconductor processing solution according to claim 13 or 14, wherein the pH of the semiconductor processing solution is 8.5 or more and 11.0 or less.

16. the semiconductor processing solution contains iodate ions, The ratio of the concentration of iodate ions to the total concentration of Ca, Na, and K is 1 or more and 1x10 ８ 16. The semiconductor processing solution according to claim 14, wherein:

17. the semiconductor processing solution contains iodide ions, The ratio of the concentration of iodide ions to the total concentration of Cr, Ni and Al is 1 or more and 1x10 ８ 16. The semiconductor processing solution according to claim 14, wherein:

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