Etching solution composition and etching method

Abstract

The present invention provides an etching solution composition in a single state sample that can reduce etching unevenness. The present invention relates to an etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid containing at least nitric acid, and water, and the pH value is below 1; wherein the etching inhibitor is selected from polyalkylimide and at least one nitrogen-containing compound containing structural units derived from diallylamine.

Description

[Technical Field]

[0001] This invention relates to an etching solution composition and an etching method using the same. [Previous Technology]

[0002] In the manufacturing process of semiconductor devices, the following steps are performed: etching a layer containing at least one metal, such as tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, aluminum oxide, aluminum, and iridium, to process it into a specific pattern shape. In recent years, the semiconductor field has been undergoing hyper-integration, which requires more complex or miniaturized wiring. The requirements for pattern processing technology or etching solutions are also constantly increasing, and various etching methods have been proposed (Patent Documents 1-3).

[0003] For example, Japanese Patent Application Publication No. 2018-6715 (Patent Document 1) discloses a method that uses an etching solution composition containing nitric acid and water to etch a tungsten film and a titanium nitride film together. Japanese Patent Application Publication No. 2019-114791 (Patent Document 2) discloses a method that uses hydrogen peroxide and one of a strong acid or a strong base to etch a tungsten layer. Korean Patent Publication No. 10-2014-0065771 (Patent Document 3) discloses a method that uses hydrogen peroxide, phosphoric acid, and an amine or amide polymer to etch a tungsten film and a titanium nitride film together. [Summary of the Invention]

[0004] The present invention relates to an etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid containing at least nitric acid, and water, and the pH value is below 1; wherein the etching inhibitor is selected from polyalkylimide and at least one nitrogen-containing compound containing structural units derived from diallylamine.

[0005] This invention relates to an etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid comprising phosphoric acid, acetic acid, and nitric acid, and water, and has a pH value of 1 or less; the etching inhibitor is a nitrogen-containing compound with an etching inhibition rate of 30% or more obtained under the following conditions. Here, the etching inhibition rate is defined as the value obtained by subtracting the relative speed A of the etching rate of the etching solution composition when etching is performed using a mixed acid aqueous solution at a specific temperature and for a specific time at a rate of 100; the mixed acid aqueous solution contains phosphoric acid, acetic acid, nitric acid, and water, and the mass ratio of the amounts of phosphoric acid, acetic acid, and nitric acid is the same as the mass ratio of the amounts of phosphoric acid, acetic acid, and nitric acid in the etching solution composition, and the total amount of phosphoric acid, acetic acid, and nitric acid is 86 by mass.

[0006] In one embodiment, the present invention relates to an etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid containing at least nitric acid, and water, and the pH value is below 1; wherein the etching inhibitor is a nitrogen-containing compound capable of causing the surface zeta potential of the metal contained in the etched layer to exceed 0 mV and be below 50 mV.

[0007] In one embodiment, the present invention relates to an etching method, which includes the step of etching a layer containing at least one metal using the etching solution composition of the present invention.

Implementation Method

[0008] In previous etching methods, there were cases where the etched layer containing metals such as tungsten was over-etched, resulting in uneven etching. Especially in the semiconductor wafer manufacturing process, from the point of view of productivity and yield, it is required that the etching solution is not prone to producing uneven etching.

[0009] Therefore, the present invention provides an etching solution composition capable of reducing etching unevenness and an etching method using the same.

[0010] According to the present invention, an etching solution composition capable of reducing etching unevenness is provided in a single state sample.

[0011] The present invention is based on the following understanding: by using an etching solution containing at least an acid including nitric acid, an etching inhibitor, and water, the etching rate can be slowed down and etching unevenness can be reduced.

[0012] This invention relates, in one embodiment, to an etching solution composition (hereinafter also referred to as "the etching solution composition of this invention") for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid comprising at least nitric acid, and water, and has a pH value of 1 or less; the etching inhibitor is selected from at least one nitrogen-containing compound selected from polyalkylimide and polymers containing structural units derived from diallylamine. According to the etching solution composition of this invention, uneven etching can be reduced.

[0013] Although the details of the mechanism of action of the present invention are not clear, it is speculated as follows. By coating or forming a thick protective film on the surface of the etched layer without gaps, there is a tendency to increase the etching inhibition rate. It is believed that in the present invention, since the specific nitrogen-containing compound, which acts as an etching inhibitor, selectively adsorbs onto the etched layer, protects the surface of the etched layer, and etches slowly, it can reduce etching unevenness. Furthermore, since the zeta potential of the surface of the metal contained in the etched layer is negative under acidic conditions, and the nitrogen-containing compound, which acts as an etching inhibitor of the present invention, carries a positive charge under acidic conditions, it is easily selectively adsorbed onto the etched layer. Therefore, it is believed that in the present invention, since the specific nitrogen-containing compound, which acts as an etching inhibitor, protects the surface of the metal contained in the etched layer and etches slowly, it can reduce etching unevenness. Moreover, regarding the previous etching using hydrogen peroxide, it is easy to generate multiple oxidation states or oxides of the metal contained in the etched layer, which is speculated to easily cause etching unevenness. Furthermore, regarding nitrogen-containing compounds other than the etching inhibitors of this invention (such as polyalkylene polyamines), it is not easy for a protective film to form on the surface of the metal contained in the etched layer, which presumably leads to uneven etching. However, this invention may also be interpreted without being limited to these mechanisms.

[0014] [Etching Inhibitor] The etching inhibitor contained in the etching solution composition of the present invention can be used alone or in combination with two or more.

[0015] From the viewpoint of reducing etching unevenness, the etching inhibitor in this invention preferably has an etching inhibition rate of 20% or more, more preferably 30% or more, more preferably 40% or more, more preferably 50% or more, more preferably 60% or more, more preferably 70% or more, more preferably 80% or more, more preferably 85% or more, more preferably 90% or more, and more preferably 94% or more. In this invention, the etching inhibition rate refers to the rate of reduction in etching speed when using an etching inhibitor compared to when not using an etching inhibitor. In one or more embodiments, the etching inhibition rate can be set as a value obtained by subtracting the relative speed A of the etching rate of the above-mentioned etching solution composition when the etching rate is set to 100 when etching is performed using a mixed acid aqueous solution at a specific temperature and for a specific time. The mixed acid aqueous solution contains phosphoric acid, acetic acid, nitric acid, and water. The mass ratio of the amounts of phosphoric acid, acetic acid, and nitric acid is the same as the mass ratio of the amounts of phosphoric acid, acetic acid, and nitric acid in the above-mentioned etching solution composition, and the total amount of phosphoric acid, acetic acid, and nitric acid is 86% by mass. Furthermore, the mass ratio of the amounts of each component in the mixed acid aqueous solution can be appropriately set. In one or more embodiments, the etching inhibition rate can be measured by ensuring that the temperature, time, and other conditions meet the conditions for etching. The conditions for measuring the etching inhibition rate vary depending on the metal contained in the etched layer. As a preferred range for the temperature and time when measuring the etching inhibition rate, the preferred range of etching temperature and etching time in the etching step of the present invention described later can be exemplified in one or more embodiments. For example, the specific temperature and time for measuring the etching inhibition rate can be set to 90°C for 120 minutes when the metal plate used in the measurement is a tungsten or titanium plate; and to 40°C for 10 minutes when the metal plate is a molybdenum, nickel, cobalt, or copper plate. The shape of the metal plate used in the measurement can be, for example, a plate-like object 2 cm long, 2 cm wide, and 0.1 mm thick. Specifically, the etching inhibition rate can be obtained using the method described in the examples.

[0016] As an etching inhibitor in the present invention, in one or more embodiments, from the viewpoint of reducing etching unevenness, it is preferably a nitrogen-containing compound with an etching inhibition rate of 30% or more obtained under the above conditions. Therefore, the present invention relates to an etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid comprising phosphoric acid, acetic acid, and nitric acid, and water, and has a pH value of 1 or less; the etching inhibitor is a nitrogen-containing compound with an etching inhibition rate of 30% or more obtained under the above conditions.

[0017] As an etching inhibitor in this invention, at least one nitrogen-containing compound selected from polyalkylimides and polymers containing structural units derived from diallylamine can be cited in one or more embodiments. Examples of the aforementioned polyalkylimides include polyethylimides. Examples of the aforementioned polymers containing structural units derived from diallylamine include diallylamine / sulfur dioxide copolymers. Among these, as an etching inhibitor, in one or more embodiments, polyalkylimides are preferred from the viewpoint of reducing etching unevenness, and polyethylimides are more preferred. Polyalkylimides such as polyethylimides readily form a protective film on the surface of the metal contained in the etched layer, inhibiting both the oxidation of the metal contained in the etched layer and the dissolution of the oxide of the metal, thereby appropriately inhibiting etching.

[0018] In one or more embodiments, the average molecular weight of the etching inhibitor is preferably 300 or more, and more preferably 100,000 or less, from the viewpoint of further reducing etching unevenness. When the etching inhibitor is a polyalkylimide, in one or more embodiments, the number average molecular weight of the etching inhibitor is preferably 300 or more, more preferably 600 or more, and even more preferably 1,200 or more, from the viewpoint of further reducing etching unevenness; and, from the viewpoint of viscosity, it is preferably 100,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less. More specifically, the number average molecular weight of the etching inhibitor is preferably 300 or more and 100,000 or less, more preferably 600 or more and 5,000 or less, and even more preferably 1,200 or more and 3,000 or less. Furthermore, when the etching inhibitor is a polymer containing structural units derived from diallylamine, the weight-average molecular weight of the etching inhibitor in one or more embodiments, from the viewpoint of further reducing etching unevenness, is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more, and preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 7,000 or less. More specifically, the molecular weight of the etching inhibitor is preferably 2,000 or more and 50,000 or less, more preferably 3,000 or more and 10,000 or less, and even more preferably 4,000 or more and 7,000 or less.

[0019] In this invention, the average molecular weight can be determined using a gel permeation chromatography (GPC) instrument under the following conditions. <GPC Conditions (Polyalkylimine)> Sample solution: Concentration adjusted to 0.1 wt% Apparatus / Detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Dissolution solution: 0.15 mol / L Na2SO4, 1% CH3COOH / water Column temperature: 40℃ Flow rate: 1.0 mL / min Sample solution injection volume: 100 μL Standard polymer: Polytriglucose of known molecular weight (Shodex P-5, P-50, P-200, P-800) <GPC Conditions (Polymers containing structural units derived from diallylamine)> Sample solution: Concentration adjusted to 0.1 wt% Detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Dissolution solution: 0.15 mol / L Na2SO4, 1% CH3COOH / water column temperature: 40℃; flow rate: 1.0 mL / min; sample solution injection volume: 100 μL; standard polymer: polytriglucose of known molecular weight (Shodex P-5, P-50, P-200, P-800).

[0020] In one or more embodiments of the present invention, the etching inhibitor is preferably selected from at least one nitrogen-containing compound of polyalkylimide and polymers containing structural units from diallylamine, with an etching inhibition rate of 30% or more obtained under the above conditions, from the viewpoint of reducing etching unevenness. Therefore, the present invention relates to an etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid containing at least nitric acid, and water, and the pH value is below 1; the etching inhibitor is selected from at least one nitrogen-containing compound of polyalkylimide and polymers containing structural units from diallylamine, with an etching inhibition rate of 30% or more obtained under the above conditions.

[0021] In one or more embodiments of the present invention, the etching inhibitor, from the viewpoint of reducing etching unevenness, is preferably a nitrogen-containing compound that can cause the zeta potential of the surface of the metal contained in the etched layer to exceed 0 mV and be 50 mV. From the viewpoint of reducing etching unevenness, the aforementioned zeta potential of the metal surface is preferably greater than 0 mV, more preferably 10 mV or more, and even more preferably 20 mV or more. Furthermore, the aforementioned zeta potential of the metal surface may also be less than 50 mV, less than 40 mV, or less than 35 mV. Therefore, in one embodiment of the present invention, there is a kind of etching solution composition for etching a layer containing at least one metal, wherein the etching solution composition contains an etching inhibitor, an acid containing at least nitric acid, and water, and the pH value is less than 1; the aforementioned etching inhibitor is a nitrogen-containing compound that can cause the zeta potential of the surface of the metal contained in the etched layer to exceed 0 mV and be 50 mV or less.

[0022] In this invention, since the zeta potential of the surface of the metal contained in the etched layer is negative under acidic conditions, and the nitrogen-containing compound, which is the etching inhibitor in this invention, carries a positive charge under acidic conditions, it is easily selectively adsorbed onto the etched layer. Therefore, it is believed that when the etch composition of this invention is used to etch the etched layer, by the change in the zeta potential of the surface of the metal contained in the etched layer to a positive value, it can be confirmed that the etching inhibitor has been adsorbed onto the surface of the metal. Since the surface of the metal is protected by the etching inhibitor and is etched slowly, uneven etching can be reduced.

[0023] From the viewpoint of reducing etching unevenness, the amount of etching inhibitor in the etching solution composition of the present invention is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more. Furthermore, from the same viewpoint, it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. More specifically, the amount of etching inhibitor in the etching solution composition of the present invention is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.5% by mass or more and 3% by mass or less. When there is a combination of two or more etching inhibitors, the amount of etching inhibitor is the total amount of those inhibitors.

[0024] [Acid] The acid contained in the etching solution composition of the present invention, from the viewpoint of uniformly etching the etched layer, is at least an acid containing nitric acid. One type of acid (nitric acid only) may be used alone, or two or more may be used together.

[0025] In one or more embodiments of the present invention, from the viewpoint of reducing etching unevenness, the acid preferably contains at least one selected from phosphoric acid and organic acids in addition to nitric acid. Examples of organic acids include at least one selected from formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, phthalic acid, trimellitic acid, glycolic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid. In one or more embodiments of the present invention, from the viewpoint of reducing etching unevenness, the acid preferably contains at least one selected from phosphoric acid and acetic acid in addition to nitric acid. For example, in one or more embodiments, an acid containing phosphoric acid, acetic acid, and nitric acid may be exemplified, and in one or more embodiments, a mixed acid containing phosphoric acid, acetic acid, and nitric acid may be exemplified.

[0026] When using a mixed acid containing phosphoric acid, acetic acid, and nitric acid as the acid in this invention, the amount of phosphoric acid in the mixed acid is preferably 50% by mass or more and 95% by mass or less, more preferably 55% by mass or more and 93% by mass or less, and even more preferably 60% by mass or more and 90% by mass or less, from the viewpoint of reducing etching unevenness. Similarly, the amount of acetic acid in the mixed acid is preferably 2% by mass or more and 80% by mass or less, more preferably 3% by mass or more and 70% by mass or less, and even more preferably 5% by mass or more and 60% by mass or less. Similarly, the amount of nitric acid in the mixed acid is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 1.5% by mass or more and 10% by mass or less. The mass ratio of phosphoric acid, acetic acid, and nitric acid (phosphoric acid / acetic acid / nitric acid) can be appropriately set, for example, to 88 / 8 / 4. In this invention, the amount of each component in the mixed acid can be regarded as the content of each component in the mixed acid in one or more embodiments.

[0027] When nitric acid is used as the acid in the present invention, the amount of nitric acid in the etching solution composition of the present invention is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less, and even more preferably 1.5% by mass or more and 5% by mass or less.

[0028] From the viewpoint of reducing etching unevenness, the amount of acid in the etching solution composition of the present invention is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. Furthermore, from the same viewpoint, it is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. More specifically, the amount of acid in the etching solution composition of the present invention is preferably 70% by mass or more and 98% by mass or less, more preferably 75% by mass or more and 95% by mass or less, and even more preferably 80% by mass or more and 90% by mass or less. When there is a combination of two or more acids, the amount of acid is the total amount of those acids.

[0029] [Water] The etching solution composition of the present invention contains water in one or more embodiments. Examples of water contained in the etching solution of the present invention include distilled water, ion-exchanged water, pure water, and ultrapure water.

[0030] From the viewpoint of reducing etching unevenness, the amount of water in the etching solution composition of the present invention is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. Furthermore, from the same viewpoint, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. More specifically, the amount of water in the etching solution composition of the present invention is preferably 2% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 7% by mass or more and 20% by mass or less.

[0031] [Other Components] The etching solution composition of the present invention may be formulated with other components within the scope of not impairing the effects of the present invention. Examples of other components include chelating agents, surfactants, solubilizers, preservatives, rust inhibitors, bactericides, antibacterial agents, and antioxidants.

[0032] From the viewpoint of reducing etching unevenness, the etching solution composition of the present invention is preferably free of hydrogen peroxide. Here, "free of hydrogen peroxide" in one or more embodiments includes: free of hydrogen peroxide, substantially free of hydrogen peroxide, or free of an amount of hydrogen peroxide that would affect the etching result. Specifically, the amount of hydrogen peroxide in the etching solution composition of the present invention is not particularly limited, but is preferably 3% by mass or less, more preferably 1% by mass or less, more preferably 0.1% by mass or less, more preferably 0.01% by mass or less, more preferably 0.001% by mass or less, and more preferably 0% by mass.

[0033] [Method for Manufacturing Etching Solution Composition] The etching solution composition of the present invention, in one embodiment, is obtained by preparing an etching inhibitor, an acid containing nitric acid, water, and any of the above-mentioned components as needed using a known method. Therefore, the present invention relates to a method for manufacturing an etching solution composition (hereinafter also referred to as "the etching solution manufacturing method of the present invention"), which includes the step of preparing at least an etching inhibitor, an acid containing nitric acid, and water. In the present invention, the phrase "preparing at least an etching inhibitor, an acid containing nitric acid, and water" in one or more embodiments includes simultaneously or sequentially mixing the etching inhibitor, the acid containing nitric acid, water, and any of the above-mentioned components as needed. The order of mixing is not particularly limited. The preparation can be carried out, for example, using a propeller mixer, a liquid circulation mixer by a pump, a homogenizer, a homogenizer, an ultrasonic disperser, and a wet ball mill. In the etching solution manufacturing method of the present invention, the preferred mixing amount of each component can be set to be the same as the preferred mixing amount of each component in the etching solution composition of the present invention described above.

[0034] In this invention, the term "the amount of each component in the etching solution composition" in one or more embodiments refers to the amount of each component in the etching solution composition used in the etching step, i.e., at the point in time when the etching process begins (when used). The amount of each component in the etching solution composition of this invention can be regarded as the content of each component in the etching solution composition of this invention in one or more embodiments. However, in cases where neutralization is involved, the amount and content may sometimes differ.

[0035] The etching solution composition of the present invention can be a so-called 1-liquid type supplied to the market with all components pre-mixed, or a so-called 2-liquid type mixed before use. As one embodiment of the 2-liquid type etching solution composition, it can be exemplified as follows: it contains a solution including an etching inhibitor (first solution) and an aqueous acid solution containing nitric acid (second solution), and the first solution and the second solution are mixed before use. The acid contained in the second solution can be the total amount of acid used to prepare the etching solution composition, or it can be a portion thereof. The first solution may also contain acid. The first solution and the second solution may each contain any of the above-mentioned components as needed.

[0036] From the viewpoint of reducing etching unevenness, the pH value of the etching solution composition of the present invention is 1 or less, preferably 0 or less, more preferably not reaching 0, and even more preferably around -1. Furthermore, the pH value of the etching solution composition of the present invention can be set to -5 or more or -3 or more. In the present invention, the pH value of the etching solution composition is a value at 25°C, which can be measured using a pH meter, specifically using the method described in the examples.

[0037] The etching solution composition of the present invention can also be stored and supplied in a concentrated state without compromising its stability. This is preferable from the viewpoint of reducing manufacturing and transportation costs. Furthermore, the concentrate can be appropriately diluted with water or an acidic aqueous solution as needed for use in the etching step. The dilution ratio can be set, for example, from 5 to 100 times.

[0038] [Kit] In other embodiments, the present invention relates to a kit for manufacturing the etching solution composition of the present invention (hereinafter also referred to as "the kit of the present invention").

[0039] As a kit of the present invention, an example is a kit (two-liquid etching solution) containing, in an immiscible state, a solution containing an etching inhibitor (first solution) and an aqueous acid solution containing at least nitric acid (second solution), which are mixed during use. The first and second solutions can be diluted with water or an aqueous acid solution as needed after mixing. The first or second solution may also contain the total amount or a portion of the water used to prepare the etching solution. The acid contained in the second solution may be the total amount or a portion of the acid used to prepare the etching solution composition. The first solution may also contain acid. The first and second solutions may each contain any of the above-mentioned components as needed. According to the kit of the present invention, an etching solution capable of reducing etching unevenness can be obtained.

[0040] [Etched Layer] The etched layer treated by the etching solution composition of the present invention, in one or more embodiments, is an etched layer containing at least one metal. Here, the metal is not particularly limited as long as it achieves the effect of the present invention, and examples include at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, aluminum oxide, aluminum, and iridium. Among these, the etching solution composition of the present invention, in one or more embodiments, is preferably used to etch an etched layer containing at least one metal selected from the group consisting of tungsten, molybdenum, niobium, tantalum, and zirconium, and in one or more embodiments, it can be suitably used to etch a tungsten film or a molybdenum film. That is, as the etched layer, a tungsten film or a molybdenum film can be exemplified in one or more embodiments. In one or more embodiments, the etching solution composition of the present invention is preferably used to etch a layer containing at least one metal selected from tungsten, molybdenum, copper, nickel, cobalt, and titanium. In one or more embodiments, it can be suitably used to etch tungsten films, molybdenum films, copper films, nickel films, cobalt films, or titanium films. That is, as the etched layer, tungsten films, molybdenum films, copper films, nickel films, cobalt films, or titanium films can be exemplified in one or more embodiments.

[0041] [Etching Method] In one embodiment, the present invention relates to an etching method (hereinafter also referred to as "the etching method of the present invention"), which includes the step of etching a layer containing at least one metal using the etching solution composition of the present invention (hereinafter also referred to as "the etching step of the present invention"). By using the etching method of the present invention, etching unevenness can be reduced in one or more embodiments.

[0042] In the etching step of the present invention, the etching process method may include, for example, immersion etching, single-piece etching, etc.

[0043] In one or more embodiments, when the etched layer is a tungsten film, the temperature (etching temperature) of the etching solution composition in the etching step of the present invention, from the viewpoint of reducing etching unevenness, is preferably 0°C or higher, more preferably 50°C or higher, and even more preferably 70°C or higher, and preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 110°C or lower. More specifically, in one or more embodiments, when the etched layer is a tungsten film, the etching temperature is preferably 0°C or higher and 150°C or lower, more preferably 50°C or higher and 130°C or lower, and even more preferably 70°C or higher and 110°C or lower. In one or more embodiments, when the etched layer is a molybdenum film, the temperature of the etching solution composition (etching temperature) in the etching step of the present invention, from the viewpoint of reducing etching unevenness, is preferably 0°C or higher, more preferably 15°C or higher, and even more preferably 25°C or higher, and preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the etched layer is a molybdenum film, the etching temperature is preferably 0°C or higher and 80°C or lower, more preferably 15°C or higher and 65°C or lower, and even more preferably 25°C or higher and 50°C or lower. In one or more embodiments, when the etched layer is a nickel film, the temperature of the etching solution composition (etching temperature) in the etching step of the present invention, from the viewpoint of reducing etching unevenness, is preferably 0°C or higher, more preferably 15°C or higher, and even more preferably 30°C or higher, and preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the etched layer is a nickel film, the etching temperature is preferably 0°C or higher and 80°C or lower, more preferably 15°C or higher and 65°C or lower, and even more preferably 30°C or higher and 50°C or lower. In one or more embodiments, when the etched layer is a cobalt film, the temperature of the etching solution composition (etching temperature) in the etching step of the present invention, from the viewpoint of reducing etching unevenness, is preferably 0°C or higher, more preferably 15°C or higher, and even more preferably 30°C or higher, and preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the etched layer is a cobalt film, the etching temperature is preferably 0°C or higher and 80°C or lower, more preferably 15°C or higher and 65°C or lower, and even more preferably 30°C or higher and 50°C or lower. In one or more embodiments, when the etched layer is a titanium film, the temperature (etching temperature) of the etching solution composition in the etching step of the present invention is preferably above 0°C, more preferably above 50°C, and even more preferably above 70°C, and preferably below 150°C, more preferably below 130°C, and even more preferably below 110°C, from the viewpoint of reducing etching unevenness.More specifically, in one or more embodiments, when the etched layer is a titanium film, the etching temperature is preferably 0°C to 150°C, more preferably 50°C to 130°C, and even more preferably 70°C to 110°C. In one or more embodiments, when the etched layer is a copper film, from the viewpoint of reducing etching unevenness, the temperature of the etching solution composition (etching temperature) in the etching step of the present invention is preferably 0°C or higher, more preferably 15°C or higher, even more preferably 30°C or higher, and preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the etched layer is a copper film, the etching temperature is preferably 0°C to 80°C, more preferably 15°C to 65°C, and even more preferably 30°C to 50°C.

[0044] In the etching step of the present invention, the etching time can be set to, for example, more than 1 minute and less than 180 minutes.

[0045] In one or more embodiments, when the etched layer is a tungsten film, the etching rate in the etching step of the present invention, from the viewpoint of improving productivity, is preferably 0.0001 g / min or more, more preferably 0.0005 g / min or more, and even more preferably 0.001 g / min or more. Furthermore, from the viewpoint of reducing etching unevenness, it is preferably 10 g / min or less, more preferably 1 g / min or less, and even more preferably 0.1 g / min or less. In one or more embodiments, when the etched layer is a molybdenum film, the etching rate in the etching step of the present invention, from the viewpoint of improving productivity, is preferably 0.01 g / min or more, more preferably 0.03 g / min or more, and even more preferably 0.05 g / min or more. Furthermore, from the viewpoint of reducing etching unevenness, it is preferably 10 g / min or less, more preferably 3 g / min or less, and even more preferably 1 g / min or less. In one or more embodiments, when the etched layer is a nickel film, the etching rate in the etching step of the present invention, from the viewpoint of improving productivity, is preferably 0.001 g / min or more, more preferably 0.005 g / min or more, and even more preferably 0.01 g / min or more. Furthermore, from the viewpoint of reducing etching unevenness, it is preferably 10 g / min or less, more preferably 1 g / min or less, and even more preferably 0.5 g / min or less. In one or more embodiments, when the etched layer is a cobalt film, the etching rate in the etching step of the present invention, from the viewpoint of improving productivity, is preferably 0.0001 g / min or more, more preferably 0.0005 g / min or more, and even more preferably 0.001 g / min or more. Furthermore, from the viewpoint of reducing etching unevenness, it is preferably 10 g / min or less, more preferably 1 g / min or less, and even more preferably 0.1 g / min or less. In one or more embodiments, when the etched layer is a titanium film, the etching rate in the etching step of the present invention, from the viewpoint of improving productivity, is preferably 0.00001 g / min or more, more preferably 0.0005 g / min or more, and even more preferably 0.001 g / min or more. Furthermore, from the viewpoint of reducing etching unevenness, it is preferably 10 g / min or less, more preferably 3 g / min or less, and even more preferably 1 g / min or less. In one or more embodiments, when the etched layer is a copper film, the etching rate in the etching step of the present invention, from the viewpoint of improving productivity, is preferably 0.0001 g / min or more, more preferably 0.0005 g / min or more, and even more preferably 0.001 g / min or more. Furthermore, from the viewpoint of reducing etching unevenness, it is preferably 10 g / min or less, more preferably 1 g / min or less, and even more preferably 0.1 g / min or less.

[0046] The etching solution composition and etching method of the present invention, in one or more embodiments, can be used to etch metals in the manufacturing process of electronic devices, especially semiconductor wafers. The etching solution composition and etching method of the present invention, in one or more embodiments, can be suitably used to fabricate semiconductor wafers. This improves etching uniformity and increases productivity and yield. The etching solution composition and etching method of the present invention, in one or more embodiments, can be used to etch electrodes in the manufacturing process of electronic devices, especially non-volatile semiconductor memory including NAND (Not AND) type flash memory. The etching solution composition and etching method of the present invention, in one or more embodiments, can be suitably used to fabricate patterns with three-dimensional structures. This allows for the acquisition of high-capacity memory and other high-performance devices. The etching solution composition and etching method of the present invention, for example, can be used in the etching method disclosed in Japanese Patent Application Publication No. 2020-145412. Examples

[0047] Hereinafter, the present invention will be specifically described with reference to embodiments, but the present invention is not limited by these embodiments in any way.

[0048] 1. Preparation of Etching Solution (Examples 1-9) The etching solutions of Examples 1-9 (pH value: -1) were prepared by mixing the etching inhibitor shown in Table 1, mixed acid (phosphoric acid / acetic acid / nitric acid, mass ratio: 88 / 8 / 4) and water. Furthermore, the mass ratio of the mixed acid was calculated by mass conversion. (Comparative Example 1) The etching solution of Comparative Example 1 was prepared by mixing phosphoric acid, acetic acid, nitric acid and water in a mass ratio of (phosphoric acid / acetic acid / nitric acid / water) 76 / 7 / 3 / 14 to obtain a mixed acid aqueous solution (pH value: -1). (Comparative Example 2) The etching solution of Comparative Example 2 (pH value: -1) was prepared by mixing the nitrogen-containing compound (arginine) shown in Table 1, mixed acid (phosphoric acid / acetic acid / nitric acid, mass ratio: 88 / 8 / 4) and water. (Comparative Example 3) The etching inhibitor of Comparative Example 3 (pH value: -1) was prepared by mixing the etching inhibitor (polyethylene imide) shown in Table 1, hydrogen peroxide, phosphoric acid and water. The proportions (mass%, effective portion) of each component in the prepared etching solution are shown in Table 1. Furthermore, the proportions of water in Table 1 also include the proportions of water contained in acidic aqueous solutions and hydrogen peroxide solutions.

[0049] The etching solution is prepared using the following components. (Etching inhibitors or nitrogen-containing compounds) Polyethylimide [Quantity average molecular weight 300, manufactured by Nippon Shokubai Co., Ltd., "EPOMIN SP-003"] Polyethylimide [Quantity average molecular weight 600, manufactured by Nippon Shokubai Co., Ltd., "EPOMIN SP-006"] Polyethylimide [Quantity average molecular weight 1,200, manufactured by Nippon Shokubai Co., Ltd., "EPOMIN SP-0012"] Polyethylimide [Quantity average molecular weight 1,800, manufactured by Nippon Shokubai Co., Ltd., "EPOMIN SP-018"] Polyethylimide [Quantity average molecular weight 10,000, manufactured by Nippon Shokubai Co., Ltd., "EPOMIN SP-200"] Polyethylimide [Quantity average molecular weight 70,000, manufactured by Nippon Shokubai Co., Ltd., "EPOMIN P-1000"] Diallylamine acetate / sulfur dioxide copolymer [Mohr ratio 50 / 50, weight average molecular weight 5,000, NITTOBO [PAS-92A manufactured by MEDICAL Co., Ltd.] N-(2-hydroxyethyl)piperazine [molecular weight 130, Nippon Emulsifier Co., Ltd.] DL-arginine [molecular weight 174, manufactured by Fujifilm and Kazumitsu Pure Chemical Co., Ltd.] (hydrogen peroxide) H2O2 [hydrogen peroxide, concentration 35% by mass, manufactured by ADEKA Co., Ltd.] (acid) Phosphoric acid [manufactured by Phosphochemical Industry Co., Ltd., concentration 85%] Acetic acid [Fujifilm and Kazumitsu Pure Chemical Co., Ltd., concentration 100%] Nitric acid [Fujifilm and Kazumitsu Pure Chemical Co., Ltd., concentration 70%] (water) Water [ultrapure water obtained using a continuous pure water production unit (Pureconti PC-2000VRL type) and subsystem (McAce KC-05H type) manufactured by Kurita Kogyo Co., Ltd.]

[0050] 2. Measurement methods for each parameter [pH value of etching solution] The pH value of the etching solution at 25°C was measured using a pH meter (manufactured by Toa DKK Corporation). The value was obtained after immersing the electrode of the pH meter in the etching solution for 1 minute.

[0051] 3-1. Evaluation of Etching Solution (Etched Layer: Tungsten Plate) [Evaluation of Etching Rate and Etching Inhibition Rate of Tungsten Plate] A tungsten plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm, whose weight was measured in advance, was immersed in the etching solutions prepared as each composition (Examples 1-9 and Comparative Examples 1-3), and etched at 90°C for 120 minutes. Afterwards, after rinsing with water, the weight of the tungsten plate was measured again, and the difference was taken as the etching amount. The weight was measured using a precision balance. Then, the etching rate of the tungsten plate was calculated according to the following formula: Etching rate (g / min) = Etching amount (g) / Etching time (min) The results of the etching rate of the tungsten plate are shown in Table 1 as relative values ​​with Comparative Example 1 set to 100 (relative rate). Furthermore, the value obtained by subtracting the relative rate of each example with the etching rate of Comparative Example 1 set to 100 from 100 is taken as the etching inhibition rate (%), and is shown in Table 1. Furthermore, the above-mentioned evaluation of etching rate and etching inhibition rate can be performed using a molybdenum plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm, or a wafer as shown in Figure 1 of Japanese Patent Application Publication No. 2020-145412, instead of a tungsten plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm.

[0052] [Evaluation of Etching Unevenness of Tungsten Plate (Surface Accuracy)] A tungsten plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm, with a pre-measured weight, was immersed in etching solutions prepared as described in Examples 1-9 and Comparative Examples 1-3, and etched at 90°C for 120 minutes. Afterward, it was washed with water, and the surface of the tungsten plate was observed again using a shape measurement laser microscope VK-9710 (lens magnification 150x) manufactured by KEYENCE Corporation. The obtained photographs were analyzed in the surface roughness mode of the instrument. Then, the surface accuracy (etching unevenness) was determined. The surface accuracy of the tungsten plate was evaluated based on the following evaluation criteria, and the results are shown in Table 1. Surface accuracy (%) = Surface roughness after etching / Surface roughness before etching × 100 <Evaluation criteria> 5: Surface accuracy is less than 120% 4: Surface accuracy is 120% or more but less than 200% 3: Surface accuracy is 200% or more but less than 300% 2: Surface accuracy is 300% or more but less than 500% 1: Surface accuracy is 500% or more but less than 700% 0: Surface accuracy is 700% or more Furthermore, the above evaluation of etching unevenness can be performed using a molybdenum plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm, or a wafer as shown in Figure 1 of Japanese Patent Application Publication No. 2020-145412, instead of a tungsten plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm.

[0053] [ζ-potential] A standard solution of 100 ppm tungsten was added to the etching solutions (Examples 1-9 and Comparative Examples 1-3) to prepare samples for ζ-potential measurement. Weight was measured using a precision balance. The prepared solution was placed in a capillary sample cell DTS1070, and the ζ-potential was measured using a "Zetasizer Nano ZS" manufactured by Malvern under the following conditions: <Measurement Conditions> Tungsten: Refractive index: 2.200, Absorbance: 0.390 Dispersion medium: Viscosity: 39 cP, Refractive index: 1.426 Temperature: 25°C

[0054] [Table 1] Table 1 composition result acid water Etching inhibitors or nitrogen-containing compounds hydrogen peroxide Etching rate of tungsten plate (%) (Relative value) Etching inhibition rate (%) of tungsten plate Zeta potential (mV) Evaluation of Etching Inhomogeneity type Mixing quantity (mass %) Mixing quantity (mass %) type Number average molecular weight or weight average molecular weight Mixing quantity (mass %) Monomer unit with ring structure Mixing quantity (mass %) Surface accuracy Example 1 Mixed acid 85.0 14.0 Polyethylimide 300 1.0 no - 14 86 twenty one 4 Example 2 Mixed acid 85.0 14.0 Polyethylene imine 600 1.0 no - 6 94 28 5 Example 3 Mixed acid 85.0 14.0 Polyethylene imine 1,800 1.0 no - 4 96 29 5 Example 4 Mixed acid 85.0 14.0 Polyethylene imine 70,000 1.0 no - 10 90 29 4 Example 5 Mixed acid 85.8 14.1 Polyethylene imine 1,800 0.1 no - 9 91 twenty two 4 Example 6 Mixed acid 85.4 14.1 Polyethylene imine 1,800 0.5 no - 6 94 25 5 Example 7 84.1 13.9 Polyethylene imine 1,800 2.0 no - 3 97 30 5 Example 8 Mixed acid 85.0 14.0 diallylamine / sulfur dioxide copolymer 5,000 1.0 yes - twenty four 76 5 3 Example 9 Mixed acid 84.1 13.9 Polyethylene imine 1,800 1.0 no - 3 97 30 5 N-(2-hydroxyethyl)piperazine Molecular weight 130 1.0 yes - Comparative Example 1 Mixed acid 86.0 14.0 - - - no - 100 0 -6 0 Comparative Example 2 Mixed acid 85.0 14.0 Arginine Molecular weight 174 1.0 no - 71 29 -3 2 Comparative Example 3 Phosphoric acid 70.2 26.15 Polyethylene imine 70,000 0.05 no 3.6 11 89 28 1

[0055] As shown in Table 1, compared with Comparative Examples 1-2 (without etching inhibitor) and Comparative Example 3 (with acid without nitric acid), the etching rate of tungsten plates in Examples 1-9 (with etching inhibitor and mixed acid, including nitric acid) was slower and the etching unevenness was reduced.

[0056] Furthermore, the following evaluation was conducted using the etching solutions of Examples 1, 3-4 and Comparative Examples 1-3.

[0057] 3-2. Evaluation of Etching Solution (Etched Layer: Nickel Plate) [Evaluation of Etching Rate and Etching Inhibition Rate of Nickel Plate] A nickel plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm was used instead of the tungsten plate described above. The etching conditions were changed to an etching temperature of 40°C and an etching time of 10 minutes. Otherwise, the nickel plate was etched in the same manner as the tungsten etching method described above, and the etching rate of the nickel plate was measured. The results of the etching rate of the nickel plate are shown in Table 2. Furthermore, the value obtained by subtracting the relative speed of each embodiment with the etching rate of Comparative Example 1 set to 100 from 100 is defined as the etching inhibition rate (%), and is shown in Table 2.

[0058] [Evaluation of Etching Unevenness of Nickel Plate (Surface Accuracy)] A nickel plate with a pre-measured weight, measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness, was immersed in the prepared etching solution (Examples 1, 3-4, and Comparative Examples 1-3) and etched at 40°C for 10 minutes. After rinsing with water, the surface of the nickel plate was observed again using a shape measurement laser microscope VK-9710 (150x lens magnification) manufactured by KEYENCE Corporation. The obtained photographs were analyzed in the surface roughness mode of the instrument. Then, the surface accuracy (etching unevenness) was determined. The surface accuracy of the nickel plate was evaluated based on the same evaluation criteria as that for the surface accuracy of tungsten described above, and the results are shown in Table 2.

[0059] [Table 2] Table 2 composition result acid water Etching inhibitors or nitrogen-containing compounds hydrogen peroxide Etching rate of nickel plate (%) (Relative value) Etching inhibition rate (%) of nickel plate Evaluation of Etching Inhomogeneity type Mixing amount (quality%) Mixing amount (quality%) type Number average molecular weight Mixing amount (quality%) Monomer unit with ring structure Mixing amount (quality%) Surface accuracy Example 1 Mixed acid 85.0 14.0 Polyethylene imine 300 1.0 no - 12 88 4 Example 3 Mixed acid 85.0 14.0 Polyethylene imine 1,800 1.0 no - 3 97 5 Example 4 Mixed acid 85.0 14.0 Polyethylene imine 70,000 1.0 no - 10 90 4 Comparative Example 1 Mixed acid 86.0 14.0 - - - no - 100 0 0 Comparative Example 2 Mixed acid 85.0 14.0 Arginine Molecular weight 174 1.0 no - 87 13 2 Comparative Example 3 Phosphoric acid 70.2 26.15 Polyethylene imine 70,000 0.05 no 3.6 twenty one 79 1

[0060] As shown in Table 2, compared with Comparative Examples 1 and 3-4, which were formulated with etching inhibitor and mixed acid (containing nitric acid), and Comparative Examples 1-2, which were not formulated with etching inhibitor, and Comparative Example 3, which was formulated with acid without nitric acid, the etching unevenness was reduced.

[0061] 3-3. Evaluation of Etching Solution (Etched Layer: Cobalt Plate) [Evaluation of Etching Rate and Etching Inhibition Rate of Cobalt Plate] A cobalt plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm was used instead of the tungsten plate described above. The etching conditions were changed to an etching temperature of 40°C and an etching time of 10 minutes. Otherwise, the cobalt plate was etched in the same manner as the tungsten etching method described above, and the etching rate of the cobalt plate was measured. The results of the etching rate of the cobalt plate are shown in Table 3. Furthermore, the value obtained by subtracting the relative speed of each embodiment with the etching rate of Comparative Example 1 set to 100 from 100 is defined as the etching inhibition rate (%), and is shown in Table 3.

[0062] [Evaluation of Etching Unevenness of Cobalt Plate (Surface Accuracy)] A cobalt plate with a pre-measured weight, measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness, was immersed in the prepared etching solution (Examples 1, 3-4, and Comparative Examples 1-3) and etched at 40°C for 10 minutes. After rinsing with water, the surface of the cobalt plate was observed again using a shape measurement laser microscope VK-9710 (150x lens magnification) manufactured by KEYENCE Corporation. The obtained photographs were analyzed in the surface roughness mode of the instrument. Then, the surface accuracy (etching unevenness) was determined. The surface accuracy of the cobalt plate was evaluated based on the same evaluation criteria as that for the surface accuracy of tungsten described above, and the results are shown in Table 3.

[0063] [Table 3] Table 3 composition result acid water Etching inhibitors or nitrogen-containing compounds hydrogen peroxide Etching rate of cobalt plate (%) (Relative value) Etching inhibition rate (%) of cobalt plate Evaluation of Etching Inhomogeneity type Mixing amount (quality%) Mixing amount (quality%) type Number average molecular weight Mixing amount (quality%) Monomer unit with ring structure Mixing amount (quality%) Surface accuracy Example 1 Mixed acid 85.0 14.0 Polyethylene imine 300 1.0 no - 76 twenty four 3 Example 3 Mixed acid 85.0 14.0 Polyethylene imine 1,800 1.0 no - 55 45 4 Example 4 Mixed acid 85.0 14.0 Polyethylene imine 70,000 1.0 no - 60 40 3 Comparative Example 1 Mixed acid 86.0 14.0 - - - no - 100 0 0 Comparative Example 2 Mixed acid 85.0 14.0 Arginine Molecular weight 174 1.0 no - 97 3 2 Comparative Example 3 Phosphoric acid 70.2 26.15 Polyethylene imine 70,000 0.05 no 3.6 55 45 1

[0064] As shown in Table 3, compared with Comparative Examples 1, 3-4, which were formulated with etching inhibitor and mixed acid (containing nitric acid), and Comparative Examples 1-2, which were not formulated with etching inhibitor, and Comparative Example 3, which was formulated with acid without nitric acid, the etching unevenness was reduced.

[0065] 3-4. Evaluation of Etching Solution (Etched Layer: Titanium Plate) [Evaluation of Etching Rate and Etching Inhibition Rate of Titanium Plate] A titanium plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm was used instead of the aforementioned tungsten plate. The titanium plate was etched using the same method as the tungsten etching method described above, and the etching rate of the titanium plate was measured. The results of the etching rate of the titanium plate are shown in Table 4. Furthermore, the value obtained by subtracting the relative speed of each embodiment (with the etching rate of Comparative Example 1 set to 100) from 100 is defined as the etching inhibition rate (%), and is shown in Table 4.

[0066] [Evaluation of Etching Unevenness of Titanium Plate (Surface Accuracy)] A titanium plate with a pre-measured weight, measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness, was immersed in the prepared etching solution (Examples 1, 3-4, and Comparative Examples 1-3) and etched at 90°C for 120 minutes. After rinsing with water, the surface of the titanium plate was observed again using a shape measurement laser microscope VK-9710 (150x lens magnification) manufactured by KEYENCE Corporation. The obtained photographs were analyzed in the surface roughness mode of the instrument. Then, the surface accuracy (etching unevenness) was determined. The surface accuracy of the titanium plate was evaluated based on the same evaluation criteria as that for the surface accuracy of the tungsten plate described above, and the results are shown in Table 4.

[0067] [Table 4] Table 4 composition result acid water Etching inhibitors or nitrogen-containing compounds hydrogen peroxide Etching rate of titanium plate (%) (Relative value) Etching inhibition rate (%) of titanium plate Evaluation of Etching Inhomogeneity type Mixing quantity (mass %) Mixing quantity (mass %) type Number average molecular weight Mixing quantity (mass %) Monomer unit with ring structure Mixing quantity (mass %) Surface accuracy Example 1 Mixed acid 85.0 14.0 Polyethylene imine 300 1.0 no - 28 72 3 Example 3 Mixed acid 85.0 14.0 Polyethylene imine 1,800 1.0 no - 17 83 5 Example 4 Mixed acid 85.0 14.0 Polyethylene imine 70,000 1.0 no - twenty one 79 4 Comparative Example 1 Mixed acid 86.0 14.0 - - - no - 100 0 0 Comparative Example 2 Mixed acid 85.0 14.0 Arginine Molecular weight 174 1.0 no - 93 7 2 Comparative Example 3 Phosphoric acid 70.2 26.15 Polyethylene imine 70,000 0.05 no 3.6 27 73 1

[0068] As shown in Table 4, compared with Comparative Examples 1, 3-4, which were formulated with etching inhibitor and mixed acid (containing nitric acid), and Comparative Examples 1-2, which were not formulated with etching inhibitor, and Comparative Example 3, which was formulated with acid without nitric acid, the etching unevenness was reduced.

[0069] 3-5. Evaluation of Etching Solution (Etched Layer: Copper Plate) [Evaluation of Etching Rate and Etching Inhibition Rate of Copper Plate] A copper plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm was used instead of the tungsten plate described above. The etching conditions were changed to an etching temperature of 40°C and an etching time of 10 minutes. Otherwise, the copper plate was etched in the same manner as the tungsten etching method described above, and the etching rate of the copper plate was measured. The results of the etching rate of the copper plate are shown in Table 5. Furthermore, the value obtained by subtracting the relative speed of each embodiment with the etching rate of Comparative Example 1 set to 100 from 100 is defined as the etching inhibition rate (%), and is shown in Table 5.

[0070] [Evaluation of Etching Unevenness of Copper Plate (Surface Accuracy)] A copper plate with a pre-measured weight, measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness, was immersed in the prepared etching solution (Examples 1, 3-4, and Comparative Examples 1-3) and etched at 40°C for 10 minutes. After rinsing with water, the surface of the copper plate was observed again using a shape measurement laser microscope VK-9710 (150x magnification) manufactured by KEYENCE Corporation. The obtained photographs were analyzed in the surface roughness mode of the instrument. Then, the surface accuracy (etching unevenness) was determined. The surface accuracy of the copper plate was evaluated based on the same evaluation criteria as that for the surface accuracy of tungsten described above, and the results are shown in Table 5.

[0071] [Table 5] Table 5 composition result acid water Etching inhibitors or nitrogen-containing compounds hydrogen peroxide Etching rate of copper plate (%) (Relative value) Etching inhibition rate (%) of copper plate Evaluation of Etching Inhomogeneity type Mixing quantity (mass %) Mixing quantity (mass %) type Number average molecular weight Mixing quantity (mass %) Monomer unit with ring structure Mixing quantity (mass %) Surface accuracy Example 1 Mixed acid 85.0 14.0 Polyethylene imine 300 1.0 no - 55 45 3 Example 3 Mixed acid 85.0 14.0 Polyethylene imine 1,800 1.0 no - 42 58 4 Example 4 Mixed acid 85.0 14.0 Polyethylene imine 70,000 1.0 no - 49 51 3 Comparative Example 1 Mixed acid 86.0 14.0 - - - no - 100 0 0 Comparative Example 2 Mixed acid 85.0 14.0 Arginine Molecular weight 174 1.0 no - 92 8 2 Comparative Example 3 Phosphoric acid 70.2 26.15 Polyethylene imine 70,000 0.05 no 3.6 56 44 1

[0072] As shown in Table 5, compared with Comparative Examples 1 and 3-4, which contained an etching inhibitor and a mixed acid (including nitric acid), and Comparative Example 1-2, which did not contain an etching inhibitor, and Comparative Example 3, which contained an acid without nitric acid, the etching unevenness was reduced. [Industrial Applicability]

[0073] The etching solution composition of the present invention can reduce etching unevenness and is useful in the manufacturing method of high-capacity semiconductor memory.

Claims

1. An etching solution composition for etching a layer containing at least one metal selected from the group consisting of tungsten, molybdenum, copper, nickel, and cobalt, wherein the etching solution composition contains an etching inhibitor, an acid comprising phosphoric acid, acetic acid, and nitric acid, and water, and has a pH value of 1 or less; the amount of the acid in the etching solution composition is 70% by mass or more and 98% by mass or less; the etching inhibitor is at least one nitrogen-containing compound selected from polyalkylimide and polymers containing structural units derived from diallylamine; the amount of the etching inhibitor is 0.01% by mass or more and 10% by mass or less; when the etching inhibitor is a polyalkylimide, the number average molecular weight of the etching inhibitor is 1,200 or more, and when the etching inhibitor is a polymer containing structural units derived from diallylamine, the weight average molecular weight of the etching inhibitor is 2,000 or more.

2. The etching solution composition of claim 1, wherein the etching inhibitor is poly(ethylene imine).

3. The etching solution composition of claim 1, wherein the amount of the etching inhibitor is 0.1% by mass or more and 5% by mass or less.

4. The etching solution composition of claim 1, wherein the amount of phosphoric acid in the acid is 50% by mass or more and 95% by mass or less.

5. The etching solution composition of claim 1, wherein the amount of acetic acid in the acid is more than 2% by mass and less than 80% by mass.

6. The etching solution composition of claim 1, wherein the amount of nitric acid in the acid is more than 0.5% by mass and less than 20% by mass.

7. The etching solution composition of claim 1, wherein the amount of water is 7% by mass or more and 20% by mass or less.

8. The etching solution composition of claim 1, wherein the pH value is below 0.

9. The etching solution composition of claim 2, wherein the number of the etching inhibitors has an average molecular weight of 1,200 or more and 3,000 or less.

10. The etching solution composition of claim 1, wherein the etching solution composition is free of hydrogen peroxide.

11. An etching method comprising the step of etching an etchable layer containing at least one metal selected from the group consisting of tungsten, molybdenum, copper, nickel and cobalt using an etchant composition as claimed in any one of claims 1 to 10.