JP2016157714A - Etchant, etching method and manufacturing method of semiconductor substrate product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etchant capable of removing titanium on a substrate, an etching method using the etchant, and a manufacturing method of a semiconductor substrate product, and further, if necessary, to provide an etchant capable of selectively removing a layer containing titanium while suppressing damages of a layer containing silicon or germanium on a substrate, specifically a silicide layer thereof, an etching method using the etchant, and a manufacturing method of a semiconductor substrate product.SOLUTION: An etchant used for a semiconductor process contains fluorine ions and a substituted hydroquinone compound.SELECTED DRAWING: None

Description

  The present invention relates to an etching solution, an etching method, and a method for manufacturing a semiconductor substrate product.

Integrated circuit manufacturing is composed of various processing steps in multiple stages. In the manufacturing process, deposition of various materials, lithography, etching, and the like are repeated many times. Among them, etching is an important process. Certain materials must be selectively etched, and other materials must remain without being corroded. In some cases, it is required to remove only predetermined layers while leaving layers made of similar metal species or layers made of a more corrosive material. The size of wirings and integrated circuits in a semiconductor substrate is becoming increasingly smaller, and the importance of performing accurate etching without corroding the members to be left is increasing.
Taking a field effect transistor as an example, with the rapid miniaturization, there is a strong demand for thinning a silicide layer formed on the upper surface of a source / drain region and for developing a new material. In a salicide process (Salicide: Self-Aligned Silicide) for forming the silicide layer, a part of the source and drain regions made of silicon or the like formed on the semiconductor substrate and the metal layer attached to the upper surface thereof are annealed. Thereby, a low-resistance silicide layer can be formed on the upper side of the source / drain electrodes and the like.
After the salicide process, the metal layer left there is removed by etching. This etching is usually performed by wet etching, and a mixed solution of hydrochloric acid and nitric acid (aqua regia) is applied as the chemical solution. Patent Document 1 discloses an example in which a chemical solution in which toluenesulfonic acid is added in addition to nitric acid and hydrochloric acid is used to remove Ni and Pt.

International Publication No. 2012/125401 Pamphlet

  An object of this invention is to provide the etching liquid which can remove the titanium on a board | substrate, the etching method using the same, and the manufacturing method of a semiconductor substrate product. Furthermore, if necessary, an etching solution that can selectively remove a layer containing titanium while suppressing damage to a layer containing silicon or germanium on the substrate, particularly a silicide layer thereof, an etching method using the same, and An object is to provide a method for manufacturing a semiconductor substrate product.

Ｒ^Ｈ１は置換基を表す。ｍ１は１〜４の整数を表す。
〔９〕Ｒ^Ｈ１が炭化水素基である〔８〕に記載のエッチング液。
〔１０〕Ｒ^Ｈ１がアルキル基である〔９〕に記載のエッチング液。
〔１１〕上記置換ヒドロキノン化合物のＣｌｏｇＰ値が１以上１０以下である〔１〕〜〔１０〕のいずれか１つに記載のエッチング液。
〔１２〕上記置換ヒドロキノン化合物が２，５−ジ−ｔｅｒｔ−ブチルヒドロキノン、２−ｔｅｒｔ−ブチルヒドロキノン、２，５−ジメチルヒドロキノン、または２−メチルヒドロキノンである〔１〕〜〔１１〕のいずれか１つに記載のエッチング液。
〔１３〕上記置換ヒドロキノン化合物のシリコン基板に対する腐食電位が−０．２５以上０．５以下である〔１〕〜〔１２〕のいずれか１つに記載のエッチング液。
〔１４〕上記有機溶媒がアルコール化合物またはエーテル化合物からなる〔２〕に記載のエッチング液。
〔１５〕上記有機溶媒が下記式（Ｏ−１）で表される化合物からなる〔２〕に記載のエッチング液。

Ｒ^Ｏ１−（−Ｏ−Ｒ^Ｏ２−）_ｎ−ＯＲ^Ｏ３ ・・・ （Ｏ−１）

Ｒ^Ｏ１およびＲ^Ｏ３はそれぞれ独立に、水素原子又は炭素数１〜１２のアルキル基、炭素数６〜１４のアリール基、または炭素数７〜１５のアラルキル基である。
Ｒ^Ｏ２は直鎖状又は分岐状の炭素数１以上１２以下のアルキレン鎖である。複数のＲ^Ｏ２が存在するときそのそれぞれは異なっていてもよい。
ｎは０以上１２以下の整数である。ただし、ｎが０であるときに、Ｒ^Ｏ１およびＲ^Ｏ３がともに水素原子であることはない。
〔１６〕上記半導体プロセス用の基板が、チタンを含む層とチタンシリサイドを含む層とを有する〔１〕〜〔１５〕のいずれか１つに記載のエッチング液。
〔１７〕上記チタンを含む層のエッチング速度を上記チタンシリサイドを含む層のエッチング速度で除した値が、４以上１５以下である〔１６〕に記載のエッチング液。
〔１８〕〔１〕〜〔１７〕のいずれか１つに記載のエッチング液を適用して、チタンを含む層のエッチングをするエッチング方法。
〔１９〕チタンシリサイドのエッチングを抑制しつつ、上記チタンを含む層のエッチングをする〔１８〕に記載のエッチング方法。
〔２０〕〔１８〕または〔１９〕に記載のエッチング方法を介して、半導体基板製品を製造する半導体基板製品の製造方法。 The above problem has been solved by the following means.
[1] An etching solution for a semiconductor process, which contains fluorine ions and a substituted hydroquinone compound.
[2] The etching solution according to [1], further containing an organic solvent.
[3] The etching solution according to [1] or [2], further containing water.
[4] The etching solution according to any one of [1] to [3], wherein the fluorine ion concentration is 0.1% by mass or more and 20% by mass or less.
[5] The etching solution according to any one of [1] to [4], wherein the concentration of the substituted hydroquinone compound is 0.1% by mass or more and 10% by mass or less.
[6] The etching solution according to [2], wherein the concentration of the organic solvent is 50% by mass or more and 98% by mass or less.
[7] The etching solution according to [3], wherein the water concentration is 0.1% by mass or more and 50% by mass or less.
[8] The etching solution according to any one of [1] to [7], wherein the substituted hydroquinone compound is represented by the following formula (H1).

R ^H1 represents a substituent. m1 represents an integer of 1 to 4.
[9] The etching solution according to [8], wherein R ^H1 is a hydrocarbon group.
[10] The etching solution according to [9], wherein R ^H1 is an alkyl group.
[11] The etching solution according to any one of [1] to [10], wherein the ClogP value of the substituted hydroquinone compound is 1 or more and 10 or less.
[12] Any one of [1] to [11], wherein the substituted hydroquinone compound is 2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone, 2,5-dimethylhydroquinone, or 2-methylhydroquinone. The etching liquid as described in one.
[13] The etching solution according to any one of [1] to [12], wherein the corrosion potential of the substituted hydroquinone compound with respect to the silicon substrate is from −0.25 to 0.5.
[14] The etching solution according to [2], wherein the organic solvent is an alcohol compound or an ether compound.
[15] The etching solution according to [2], wherein the organic solvent comprises a compound represented by the following formula (O-1).

R ^O1 — (— O—R ^O2 —) _n —OR ^O3 (O-1)

R ^O1 and R ^O3 are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms.
R ^O2 is a linear or branched alkylene chain having 1 to 12 carbon atoms. When a plurality of R ^O2 are present, each of them may be different.
n is an integer of 0 or more and 12 or less. However, when n is 0, both R ^O1 and R ^O3 are not hydrogen atoms.
[16] The etching solution according to any one of [1] to [15], wherein the semiconductor process substrate has a layer containing titanium and a layer containing titanium silicide.
[17] The etching solution according to [16], wherein a value obtained by dividing the etching rate of the layer containing titanium by the etching rate of the layer containing titanium silicide is 4 or more and 15 or less.
[18] An etching method of etching a layer containing titanium by applying the etching solution according to any one of [1] to [17].
[19] The etching method according to [18], wherein the titanium-containing layer is etched while suppressing etching of titanium silicide.
[20] A semiconductor substrate product manufacturing method for manufacturing a semiconductor substrate product through the etching method according to [18] or [19].

  According to the etching solution of the present invention, the etching method using the same, and the semiconductor substrate product manufacturing method, titanium on the substrate can be removed. Further, if necessary, the layer containing silicon or germanium, particularly the silicide layer thereof can be prevented from being damaged, and the layer containing titanium can be selectively removed.

It is sectional drawing which shows typically the manufacturing process example of the semiconductor substrate in one Embodiment of this invention. It is process drawing which shows the manufacture example of the MOS transistor in one Embodiment of this invention. It is an apparatus block diagram which shows a part of wet etching apparatus which concerns on preferable embodiment of this invention. It is a top view which shows typically the movement locus line of the nozzle with respect to the semiconductor substrate in one Embodiment of this invention.

  First, a preferred embodiment of an etching process according to application of the etching solution of the present invention will be described with reference to FIGS.

[Etching process]
FIG. 1 shows the semiconductor substrate before and after etching. In the manufacturing example of this embodiment, the metal layer (second layer) 1 is disposed on the upper surface of the silicon (silicon) or germanium-containing layer (first layer) 2. As the silicon or germanium-containing layer (first layer), a Si epitaxial layer constituting a source electrode and a drain electrode is applied. The first layer may be made of Si, or may be a SiGe or Ge epitaxial layer.

The constituent material of the metal layer (second layer) 1 is titanium (Ti). The metal layer can be formed by a method usually applied to this type of metal film, and specifically, film formation by CVD (Chemical Vapor Deposition) can be mentioned. The thickness of the metal layer at this time is not particularly limited, but examples include a film having a thickness of 5 nm to 50 nm. In the present invention, it is preferable that the metal layer is a Ti layer because the removal performance of the etching solution is sufficiently exhibited.
The metal layer may contain other elements in addition to the metal atoms listed above. For example, oxygen and nitrogen inevitably mixed in may exist. The amount of inevitable impurities is preferably suppressed to, for example, about 1 ppt to 10 ppm (mass basis).
In addition to the above materials, there may be a material that is not desired to be etched in the semiconductor substrate. The etching solution according to a preferred embodiment of the present invention is preferable because corrosion of such material can be further suppressed.

  After the metal layer 1 is formed on the silicon or germanium-containing layer 2 in the step (a), annealing (sintering) is performed, and a metal-Si reaction film (third layer: silicide layer) is formed at the interface. 3 is formed (step (b)). Annealing may be performed under conditions normally applied to the production of this type of device, and for example, treatment at 200 to 1000 ° C. may be mentioned. The thickness of the silicide layer 3 at this time is not particularly limited, but examples include a layer of 50 nm or less, and an example of a layer of 10 nm or less. Although there is no lower limit in particular, it is practical that it is 1 nm or more. This silicide layer is applied as a low-resistance film, and functions as a conductive portion that electrically connects a source electrode and a drain electrode located below the silicide layer and a wiring disposed thereon. Accordingly, when defects or corrosion occur in the silicide layer, this conduction is hindered, which may lead to quality degradation such as device malfunction. In particular, recently, the integrated circuit structure inside the substrate has been miniaturized, and even a minute damage can have a great influence on the performance of the element. Therefore, it is desirable to prevent such defects and corrosion as much as possible.

  In the present specification, in a broad sense, the silicide layer is a concept included in the first silicon or germanium-containing layer. Therefore, when the second layer is selectively removed with respect to the first layer, not only a mode in which the second layer (metal layer) is preferentially removed with respect to the silicon or germanium-containing layer that is not silicided. This means that the second layer (metal layer) is preferentially removed with respect to the silicide layer. Strictly speaking, when the first silicon or germanium-containing layer (excluding the silicide layer) and the third silicide layer are distinguished from each other, they are referred to as the first layer and the third layer, respectively. The silicon layer may be any of single crystal silicon, polycrystalline silicon, and amorphous silicon. The term “silicide layer” simply includes a composite metal layer formed by annealing each metal. Therefore, the term “titanium silicide” includes not only a silicide of titanium and silicon but also a silicide made of titanium, silicon and germanium, and a silicide made of titanium and germanium. In the present invention, it is preferable to apply to the protection of a silicide layer (TiSi) made of titanium and silicon or a silicide layer (TiSiGe) made of titanium, silicon, and germanium from the viewpoint that the effect becomes remarkable. It is more preferable to apply to the protection of a silicide layer (TiSi) made of silicon.

Next, the remaining metal layer 1 is etched (step (b)-> step (c)). In the present embodiment, an etching solution is applied at this time, and the metal layer 1 is removed by applying and contacting the etching solution from the upper side of the metal layer 1. The form of applying the etching solution will be described later.
The silicon or germanium-containing layer 2 is made of an Si or SiGe epitaxial layer, and can be formed by crystal growth on a silicon substrate having specific crystallinity by a chemical vapor deposition (CVD) method. Alternatively, an epitaxial layer formed with desired crystallinity may be formed by an electron beam epitaxy (MBE) method or the like.
In order to make the silicon or germanium-containing layer a P-type layer, it is preferable that boron (B) having a concentration of about 1 × 10 ¹⁴ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ is doped. In order to form an N-type layer, it is preferable that phosphorus (P) or arsenic (As) is doped at a concentration of 1 × 10 ¹⁴ cm ⁻³ to 1 × 10 ²¹ cm ⁻³ .

When the first layer is a SiGe epitaxial layer, the Ge concentration is preferably 20% by mass or more, and more preferably 40% by mass or more. As an upper limit, 100 mass% or less is preferable, and 90 mass% or less is more preferable. In the case of 100% by mass of germanium, the layer formed by annealing with the alloy of the second layer contains germanium and the specific metal element of the second layer, and does not contain silicon. For convenience, this is referred to as a germanium “silicide” layer.
In this specification, the concentration of germanium is a value measured by the following measuring method. The substrate of the layer containing germanium (Ge) is etched in the depth direction from 0 to 30 nm by etching ESCA (Quanta, manufactured by ULVAC-PHI), and the average value of Ge concentration in the analysis result of 3 to 15 nm is Ge concentration (mass%) And

  Through the salicide process, the silicide layer is formed between the silicon or germanium-containing layer (first layer) and the metal layer (second layer), and silicon (Si) or germanium (Ge) and the components of the second layer (above It is formed as a layer containing a specific metal species). This silicide layer is included in the first layer in a broad sense, but is referred to as a “third layer” when distinguished from this in a narrow sense. In terms of the composition, SixGeyMz (M: metal element), x + y + z = 1, 0.2 ≦ x + y ≦ 0.8, and preferably 0.3 ≦ x + y ≦ 0.7. More preferred. z is preferably 0.2 ≦ z ≦ 0.8, and more preferably 0.3 ≦ z ≦ 0.7. The preferred range of the ratio of x and y is preferably y = 0 (not including Ge), but when Ge is included, it is as defined above. However, the third layer may contain other elements. This is the same as described for the metal layer (second layer).

(Processing of MOS transistors)
FIG. 2 is a process diagram showing an example of manufacturing a MOS transistor. (A) is a MOS transistor structure formation process, (B) is a metal film sputtering process, (C) is a first annealing process, (D) is a metal film selective removal process, and (E) is a second annealing process. It is a process.
As shown in the figure, a gate electrode 23 is formed through a gate insulating film 22 formed on the surface of the silicon substrate 21. Extension regions may be separately formed on both sides of the gate electrode 23 of the silicon substrate 21. A protective layer (not shown) for preventing contact with the Ti layer may be formed on the gate electrode 23. Further, a sidewall 25 made of a silicon oxide film or a silicon nitride film is formed, and a source region 26 and a drain region 27 are formed by ion implantation.
Next, as shown in the figure, a Ti film 28 is formed and subjected to a rapid annealing process. As a result, the elements in the Ti film 28 are diffused into the silicon substrate for silicidation (in this specification, alloying by annealing is referred to as silicidation for the sake of convenience, including when germanium is 100% by mass). As a result, the upper portions of the source electrode 26 and the drain electrode 27 are silicided to form a TiSi (Ge) source electrode portion 26A and a TiSi (Ge) drain electrode portion 27A. At this time, if necessary, the electrode member is changed to a desired state (annealed silicide source electrode 26B, annealed silicide drain electrode 27B) by performing the second annealing as shown in FIG. be able to. The first and second annealing temperatures are not particularly limited, but can be performed at 400 to 1100 ° C., for example.

  The remaining Ti film 28 without contributing to silicidation can be removed by using the etching solution of the present invention (FIGS. 2C and 2D). At this time, what is shown in the figure is schematically shown, and there may or may not be a Ti film deposited and left on top of the silicided layers (26A, 27A). The structure of the semiconductor substrate or its product is also shown in a simplified manner, and may be interpreted as having necessary members as necessary.

The following forms can be illustrated if the preferable example of a constituent material is given.
21 Silicon substrate: Si, SiGe, Ge
22 Gate insulating film: HfO ₂ (High-k)
23 Gate electrode: Al, W
25 Side wall: SiOCN, SiN, SiO ₂ (low-k)
26 Source electrode: Si, SiGe, Ge
27 Drain electrode: Si, SiGe, Ge
28 Metal layer: Ti
Not shown Cap: TiN
Although the example of the semiconductor substrate to which the etching solution of the present invention is applied has been described above, the present invention is not limited to this specific example and can be applied to other semiconductor substrates. For example, a semiconductor substrate including a high dielectric film / metal gate FinFET having a silicide pattern on the source and / or drain region may be used.

  Here, if the silicide layer (third layer) or the layer (first layer) of silicon or the like is left and the difficulty of removing only the upper metal layer (second layer) is mentioned, the silicide layer is removed. The point which is comprised including the metal which should be mentioned is mentioned. That is, if a highly soluble solution component is employed in order to improve the removability of the metal layer, the silicide layer containing the metal will also be easily dissolved. In addition, when a component having high solubility of a metal (Ti, Pt, Ni, etc.) that forms silicide is applied, it is usually in the direction of showing solubility in silicon (Si) or germanium (Ge). Therefore, increasing the solubility of the metal layer while suppressing damage to the silicide layer or the like is in the opposite direction. According to a preferred embodiment of the present invention, it is possible to realize such incompatible characteristics, protect a silicide layer or the like to be left as a semiconductor substrate product, and effectively remove a metal layer on the upper side or the like. Can do.

[Etching solution]
Next, a preferred embodiment of the etching solution of the present invention will be described. The etching solution of this embodiment contains fluorine ions and a substituted hydroquinone compound. Here, the substituted hydroquinone compound means that an unsubstituted one of the hydroquinone compounds is excluded. The etching solution may further contain an organic solvent or water as necessary. In particular, it is preferable that the etching solution is substantially composed of only a fluorine ion, its counter ion, a substituted hydroquinone compound, water, and an organic solvent. Here, “substantially” means that an inevitable impurity and a trace amount of added components may be included within the range where the effects of the present invention are exhibited. Hereinafter, each component will be described.

(Fluorine ion)
The etching solution of the present invention contains fluorine ions. It is understood that the fluorine ions serve as a ligand (complexing agent) for the second layer metal (Ti or the like) in the etching solution and promote the dissolution.
The concentration of fluorine ions in the etching solution is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. As an upper limit, 20 mass% or less is preferable, 10 mass% or less is more preferable, 5 mass% or less is further more preferable, and 2 mass% or less is especially preferable. It is preferable to apply fluorine ions at the above-mentioned concentration because it is possible to achieve effective protection of the silicon or germanium layer or its silicide layer while realizing good etching of the metal layer.
In addition, in confirmation of a compounding quantity, you may specify the quantity of a fluorine ion by quantifying the quantity of the fluorine compound (salt) at the time of manufacture. Only one type of fluorine-containing compound may be used, or two or more types may be used in combination. Examples of the fluorine ion supply source include those listed below. In the present invention, hydrofluoric acid (HF) is particularly preferable.

(Substituted hydroquinone compound)
The etching liquid of the present invention contains a substituted hydroquinone compound (preferably an alkyl-substituted hydroquinone). The substituted hydroquinone compounds widely include compounds having a hydroquinone skeleton having a substituent. In the etching solution of the present invention, it is understood that the substituted hydroquinone compound has achieved proper metal removability and protection of the silicon or germanium-containing layer (preferably its silicide layer) in cooperation with the fluorine ions. Including the presumption, the difference in hydrophilicity between Ti and Si in the system containing fluorine ions acts (the latter is hydrophobic), and among the highly hydrophobic compounds, there are compounds having a specific hydroquinone skeleton. It is understood that the silicide layer is excellent in adsorptivity (protective property). As a result, it is considered that the substituted hydroquinone compound forms a specific adsorption layer with respect to the silicide layer and the like and exhibits an action of suppressing excessive damage (dissolution) from fluorine ions. On the other hand, it does not inhibit the action expected for fluorine ions (metal dissolution action, etc.), and as a result, it is understood that it exhibits both high metal layer removability and good protection against silicide layers, etc. at the same time. Is done.

The substituted hydroquinone compound is preferably represented by the following formula (H1).

R ^H1 represents a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 12 carbons, more preferably 2 to 6 and particularly preferably 2 to 4), an alkenyl group (preferably having 2 to 12 carbons and more preferably 2 to 6), An aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, particularly preferably 6 to 10 carbon atoms), an aralkyl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, and particularly preferably 6 to 10 carbon atoms). ), A hydroxyl group-containing group, a carboxyl group-containing group, a thiol group (sulfanyl group) -containing group, and an amino group-containing group (the amino group preferably has 0 to 6 carbon atoms, more preferably 0 to 3 carbon atoms). The linking group of the hydroxyl group-containing group, the carboxyl group-containing group, the thiol group-containing group, and the amino group-containing group is preferably in a form without this (single bond). When a linking group is included, the linking group is an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms) or an alkenylene group (preferably having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms). Are more preferred), O, CO, NR ^N , S, or a combination thereof. The number of atoms constituting the linking group is preferably 1-12, more preferably 1-6, particularly preferably 1-3, excluding hydrogen atoms. The number of linking atoms in the linking group is preferably 10 or less, more preferably 8 or less, and particularly preferably 3 or less. The lower limit is 1 or more. The number of connected atoms refers to the minimum number of atoms that are located in a path connecting predetermined structural portions and are involved in the connection. For example, in the case of —CH ₂ —C (═O) —O—, the number of atoms constituting the linking group is 6, but the number of linking atoms is 3.

Among these, R ^H1 is preferably a hydrocarbon group, and preferably an alkyl group, an alkenyl group, an aryl group, or an aralkyl group, and more preferably an alkyl group. In the substituted hydroquinone compound, hydrophobicity is imparted to the compound by selecting a hydrocarbon group as the substituent R ^H1 . This is particularly preferable because desired etching selectivity can be obtained.

m1 represents an integer of 1 to 4, an integer of 1 to 3 is preferable, and 1 or 2 is preferable.
When m1 is 2 or more, the plurality of R ^H1 may form a ring. Examples of the ring formed here include a 3-membered ring to a 7-membered ring, and a 5-membered ring or a 6-membered ring is preferable. Examples of the ring structure may be an aromatic ring or an aliphatic ring. Further, it may be a hydrocarbon ring or a heterocyclic ring. Especially, in this invention, it is preferable that it is an aliphatic ring, and the aliphatic ring of hydrocarbon is more preferable. Specifically, the C═C bond of the hydroquinone skeleton is regarded as a double bond, and examples thereof include a cyclohexene ring, a cyclopentene ring, and a cyclobutene ring.

  Specific examples of the substituted hydroquinone compound include 2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone, 2,5-dimethylhydroquinone, 2-methylhydroquinone and the like.

  The ClogP value of the substituted hydroquinone compound is preferably 1 or more, more preferably 2 or more, and particularly preferably 3.5 or more. There is no particular upper limit, but it is practical that it is 10 or less. The ClogP value is a value obtained by calculating the common logarithm logP of the distribution coefficient P between 1-octanol and water. Known methods and software can be used for calculating the ClogP value. However, unless otherwise specified, the present invention uses the ClogP program incorporated in ChemBioDraw Ultra 12.0 of Cambridge software. It is preferable to make the ClogP value of the substituted hydroquinone compound in the above range because the compound can be made hydrophobic and good etching selectivity can be obtained.

In the present invention, the concentration of the substituted hydroquinone compound is preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less in the etching solution, and 3% by mass. It is particularly preferred that As a minimum, 0.01 mass% or more is preferable, 0.05 mass% or more is more preferable, 0.1 mass% or more is further more preferable, and 0.5 mass% or more is especially preferable.
As for the said substituted hydroquinone compound, only 1 type may be used and 2 or more types may be used together. When using 2 or more types together, the combined use ratio is not particularly limited, but the total use amount is preferably within the above-mentioned concentration range as a total of 2 or more types.

(Organic solvent)
The etching solution according to the present invention may contain an organic solvent. Among these organic solvents, a protic polar organic solvent is preferable (however, when a protic polar organic solvent is used, it does not preclude use in combination with an aprotic polar organic solvent). Examples of the protic polar organic solvent include alcohol compound solvents. Especially, C1-C36 is preferable, 2-24 are more preferable, 4-18 are more preferable, and 4-12 are especially preferable. The organic solvent is preferably an alcohol compound or an ether compound, and more preferably an alcohol compound. Specific examples include the following.
・ Alcohol compounds: methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, polyethylene glycol (diethylene glycol, triethylene glycol, etc. ), Polypropylene glycol (dipropylene glycol, tripropylene glycol, etc.), 2-methyl-2,4-pentanediol, 1,3-butanediol, 1,4-butanediol and the like. Alternatively, as alkylene glycol monoalkyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, dipropylene glycol monomethyl Examples include ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, and dipropylene glycol monobutyl ether.

The organic solvent is preferably a compound represented by the following formula (O-1).
R ^O1 — (— O—R ^O2 —) _n —OR ^O3 (O-1)
・ R ^O1
R ^O1 and R ^O3 are each independently a hydrogen atom, an alkyl group having 1 to 12 (preferably 1 to 6, more preferably 1 to 3) carbon atoms, or an aryl having 6 to 14 (preferably 6 to 10) carbon atoms. Or an aralkyl group having 7 to 15 carbon atoms (preferably 7 to 11 carbon atoms). Of these, R ^O3 is preferably a hydrogen atom.
・ R ^O2
R ^O2 is an alkylene group having 1 to 12 carbon atoms. When a plurality of R ^O2 are present, each of them may be different. R ^O2 preferably has 2 to 10 carbon atoms, more preferably 2 to 6, and particularly preferably 2 to 4. R ^O2 may be linear or branched and may have a ring structure.
・ N
n is an integer of 0 or more and 12 or less, and preferably 0 or more and 6 or less. When n is 2 or more, the plurality of R ^O2 may be different from each other. When n = 0, both R ^O1 and R ^O3 are not hydrogen atoms.
R ^{O1 to} R ^O3 may be linked to each other to form a ring. Examples of the ring formed here include a 3-membered ring to a 7-membered ring, and a 5-membered ring or a 6-membered ring is preferable. For example, a compound in which R ^O1 and R ^O2 are linked to form a tetrahydrofuran or tetrahydropyran structure, and -OR ^O3 is substituted ^therewith .

The concentration of the organic solvent in the etching solution is preferably 99% by mass or less, more preferably 98% by mass or less, still more preferably 97% by mass or less, and preferably 96% by mass or less. Particularly preferred. As a minimum, 50 mass% or more is preferable, 60 mass% or more is more preferable, 70 mass% or more is further more preferable, 80 mass% or more is further more preferable, 90 mass% or more is especially preferable. By setting the organic solvent in the above range, the concentration of water can be reduced. On the other hand, the effects of the above-described fluorine ions and substituted hydroquinone compounds can be moderately promoted to achieve both good etching properties of the metal layer (second layer) and protective properties of the first layer to the third layer. This is preferable because it is possible.
In addition, in this invention, the said organic solvent may use only 1 type, and may use 2 or more types together. When using 2 or more types together, the combined use ratio is not particularly limited, but the total use amount is preferably within the above-mentioned concentration range as a total of 2 or more types.

In the present specification, when a compound or a substituent / linking group includes an alkyl group / alkylene group, an alkenyl group / alkenylene group, an alkynyl group / alkynylene group, etc., these may be cyclic or linear, and may be linear or branched. It may be substituted with any group or unsubstituted. In this case, an alkyl group, an alkylene group, an alkenyl group, an alkenylene group, an alkynyl group, an alkynylene group is a group containing a hetero atom (e.g., O, S, CO, NR ^N and the like) may be separated by a, with this To form a ring structure. Moreover, when an aryl group, a heterocyclic group, etc. are included, they may be monocyclic or condensed and may be similarly substituted or unsubstituted.
The above ^RN is a hydrogen atom or a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12, more preferably 1 to 6 and particularly preferably 1 to 3), and an alkenyl group (preferably having 2 to 24 carbon atoms and 2 -12 are more preferable, 2-6 are more preferable, 2-3 are particularly preferable, and an alkynyl group (C2-C24 is preferable, 2-12 are more preferable, 2-6 are more preferable, and 2-3 are Particularly preferred), an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 11 carbon atoms are preferred.
In the present specification, the technical matters such as temperature and thickness, as well as the choices of substituents and linking groups of the compounds, can be combined with each other even if the list is described independently.
In the present specification, when a compound is specified by adding it to the end of a compound or an acid, it means that in addition to the corresponding compound, its ion and salt are included within the range where the effects of the present invention are exhibited. Similarly, it is meant to include derivatives thereof.

(water)
The etching solution of the present invention preferably contains water (aqueous medium). The water (aqueous medium) may be an aqueous medium containing a dissolved component as long as the effects of the present invention are not impaired, or may contain an unavoidable trace mixed component. Among these, water that has been subjected to purification treatment such as distilled water, ion-exchanged water, or ultrapure water is preferable, and ultrapure water that is used for semiconductor manufacturing is particularly preferable. The concentration of water is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 1% by mass or more in the etching solution. As an upper limit, it is preferable that it is 50 mass% or less, It is more preferable that it is 35 mass% or less, It is more preferable that it is 15 mass% or less, It is further more preferable that it is 10 mass% or less, 5 mass% It is particularly preferred that
In the present invention, it is preferable to regulate the water concentration of the etching solution within a predetermined range. In the absence of water, the metal layer may not be sufficiently etched. Although it is preferable to apply in this respect, it is preferable to suppress this amount to an appropriate amount because damage to the silicon or germanium layer, its silicide layer, and other metal layers to be protected can be suppressed.

(Surfactant)
The etching solution of the present invention may contain a surfactant. The surfactant is not particularly limited, but is an anionic surfactant, a cationic surfactant, a nonionic surfactant, a surfactant comprising a polymer compound, a fluorosurfactant, a polyoxyalkylene surfactant. Etc. can be applied as appropriate.
The concentration of the surfactant is preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 1% by mass or less with respect to the total amount of the etching solution. As a lower limit, it is preferable to contain 0.001 mass% or more, and it is more preferable to contain 0.005 mass% or more. Surfactant may be used individually by 1 type, or may be used in combination of 2 or more type.

(PH adjuster)
In the etching solution of the present invention, a pH adjusting agent may be used. As the pH adjuster, a quaternary ammonium salt such as tetramethylammonium or choline, an alkali hydroxide or alkaline earth salt such as potassium hydroxide, or an amino compound such as 2-aminoethanol or guanidine is used to raise the pH. be able to. In order to lower the pH, inorganic acids such as carbonic acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, or formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethyl Butyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malon Examples include acids, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid.
The amount of the pH adjuster used is not particularly limited, and may be used in an amount necessary for adjusting the pH to the above range. A pH adjuster may be used individually by 1 type, or may be used in combination of 2 or more type.

(Corrosion potential)
It is preferable that the etching potential of the etching solution of the present invention is adjusted. Specifically, in the corrosion potential defined by the measurement method presented in the examples below, it is preferably −0.25 or more, more preferably −0.2 or more, further preferably −0.1 or more, 0 or more is more preferable, and 0.1 or more is particularly preferable. The upper limit is practically 0.5 or less.

(kit)
The etching solution in the present invention may be a kit in which the raw material is divided into a plurality. For example, the liquid composition which contains the said fluorine ion in an aqueous medium as a 1st liquid is prepared, and the liquid composition which contains the said substituted hydroquinone compound in an aqueous medium as a 2nd liquid is mentioned. As an example of its use, a mode in which both solutions are mixed to prepare an etching solution, and then applied to the etching process at an appropriate time is preferable. Either an organic solvent or the like may be contained. By doing so, the liquid performance is not deteriorated due to the decomposition of the substituted hydroquinone compound, and a desired etching action can be effectively exhibited. The concentration of fluorine ions in the first liquid and the concentration of the substituted hydroquinone compound in the second liquid can be appropriately set as the concentration after mixing based on the blending amount of one liquid described above.

(Concentrated liquid)
The etching solution of the present invention may be prepared as a concentrated solution. In this case, it can be used after being diluted with water at the time of use.

(container)
The etching solution of the present invention can be stored, transported and used in any container as long as corrosivity or the like is not a problem (regardless of whether it is a kit or not). For semiconductor applications, a container having a high cleanliness and a low impurity elution is preferable. Examples of the containers that can be used include, but are not limited to, “Clean Bottle” series manufactured by Aicero Chemical Co., Ltd., “Pure Bottle” manufactured by Kodama Resin Co., Ltd., and the like.

(Impurities and particles)
The etching solution of the present invention preferably has few impurities in the solution, such as a metal content, in view of its intended use. In particular, the Na, K, and Ca ion concentrations in the liquid are each preferably in the range of 1 ppt to 1 ppm (mass basis) or lower. In order to achieve such an ion concentration, it is preferable to select a raw material with a small amount of metal when preparing the constituents (raw materials) of the etching solution of the present application. It is recommended to use an organic solvent having a Ca ion concentration of 1 ppt to 1 ppm (mass basis). The organic solvent of the Example mentioned later is a thing in the range of this Na, K, and Ca ion concentration.
In the etching solution, the number of coarse particles (particles) having an average particle size of 0.5 μm or more is preferably in the range of 100 particles / cm ³ or less, and is preferably in the range of 50 particles / cm ³ or less.

[Etching conditions]
As an application example of the etching solution, an embodiment in which the etching solution is prepared and then applied to the etching treatment in a timely manner is preferable. By doing in this way, it does not cause deterioration of the liquid performance by decomposition | disassembly of each component, and a desired etching effect | action can be exhibited effectively. Here, “timely” after mixing refers to the time period after mixing until the desired action is lost, specifically within 60 minutes, more preferably within 30 minutes, and more preferably within 10 minutes. Is more preferably within 1 minute, and particularly preferably within 1 minute. Although there is no lower limit in particular, it is practical that it is 1 second or more.

  If it demonstrates using FIG. 3, the prepared etching liquid will be injected from the discharge outlet 13, and will be applied to the upper surface of the semiconductor substrate S in the processing container (processing tank) 11. FIG. In the embodiment shown in the figure, the chemical solution is supplied from A and is transferred to the discharge port 13 via the branch point 14 and the flow path fc. A flow path fd indicates a return path for reusing the chemical solution. The semiconductor substrate S is on the turntable 12 and is preferably rotated together with the turntable by the rotation drive unit M. In addition, the example which makes the branch point 14 a switching valve is given, and it can process by switching supply and return of a chemical | medical solution. Or you may apply the valve which can adjust the distribution | circulation direction made to perform this simultaneously.

In addition, the etching liquid of this invention has few impurities, for example, a metal content, etc. in a liquid in view of the use use. In particular, the Na, K, and Ca ion concentrations in the liquid are preferably in the range of 1 ppt to 1 ppm (mass basis). In the etching solution, the number of coarse particles having an average particle size of 0.5 μm or more is preferably in the range of 100 particles / cm ³ or less, and is preferably in the range of 50 particles / cm ³ or less.

In the present invention, it is preferable to use a single wafer apparatus. Specifically, the single wafer type apparatus has a processing tank, and the semiconductor substrate is transported or rotated in the processing tank, and the etching solution is applied (discharge, jetting, flowing down, dropping, etc.) into the processing tank. The etching solution is preferably brought into contact with the semiconductor substrate.
Advantages of the single wafer type apparatus include (i) a fresh etching solution is always supplied, so that reproducibility is good, and (ii) in-plane uniformity is high. The management temperature when adjusting the line temperature is preferably in the same range as the processing temperature described later.
The single wafer type apparatus is preferably provided with a nozzle in its processing tank, and a method of discharging the etching liquid onto the semiconductor substrate by swinging the nozzle in the surface direction of the semiconductor substrate is preferable. By doing so, the deterioration of the liquid can be prevented, which is preferable. In addition, it is preferable that a kit is divided into two or more liquids so that it is difficult to generate gas or the like.

The processing temperature at which etching is performed is preferably 10 ° C. or higher, and more preferably 20 ° C. or higher. The upper limit is preferably 80 ° C. or lower, more preferably 70 ° C. or lower, further preferably 60 ° C. or lower, further preferably 50 ° C. or lower, and preferably 40 ° C. or lower. Particularly preferred. By setting it to the above lower limit value or more, a sufficient etching rate for the second layer can be secured, which is preferable. By setting it to the upper limit value or less, it is preferable because the temporal stability of the etching processing rate can be maintained. In addition, the ability to process near room temperature leads to a reduction in energy consumption.
The etching processing temperature is based on the temperature applied to the substrate in the temperature measurement method shown in the examples described later. However, when the temperature is controlled by the storage temperature or batch processing, the temperature in the tank is controlled by the circulation system. In some cases, the temperature may be set in the circulation flow path.

  The supply rate of the etching solution is not particularly limited, but is preferably 0.05 to 5 L / min, and more preferably 0.1 to 3 L / min. By setting it to the above lower limit value or more, it is preferable because uniformity in the etching plane can be ensured. By setting it to the upper limit value or less, it is preferable because stable performance can be secured during continuous processing. When the semiconductor substrate is rotated, although it depends on its size and the like, it is preferably rotated at 50 to 1000 rpm from the same viewpoint as described above.

In the single-wafer etching according to a preferred embodiment of the present invention, it is preferable that the semiconductor substrate is transported or rotated in a predetermined direction, an etching solution is injected into the space, and the etching solution is brought into contact with the semiconductor substrate. . The supply rate of the etching solution and the rotation speed of the substrate are the same as those already described.
In the single wafer type apparatus configuration according to a preferred embodiment of the present invention, as shown in FIG. 4, it is preferable to apply the etching solution while moving the discharge port (nozzle). Specifically, in the present embodiment, when the etching solution is applied to the semiconductor substrate S, the substrate is rotated in the r direction. On the other hand, the discharge port is adapted to move along a movement trajectory line t extending from the center portion to the end portion of the semiconductor substrate. As described above, in this embodiment, the direction of rotation of the substrate and the direction of movement of the discharge port are set to be different from each other. As a result, the etching solution can be applied evenly over the entire surface of the semiconductor substrate, and the etching uniformity is suitably ensured.
The moving speed of the discharge port (nozzle) is not particularly limited, but is preferably 0.1 cm / s or more, and more preferably 1 cm / s or more. On the other hand, the upper limit is preferably 30 cm / s or less, and more preferably 15 cm / s or less. The movement trajectory line may be a straight line or a curved line (for example, an arc shape). In either case, the moving speed can be calculated from the actual distance of the trajectory line and the time spent for the movement. The time required for etching one substrate is preferably in the range of 10 to 300 seconds.

  The metal layer is preferably etched at a high etching rate. The etching rate [R2] of the second layer (metal layer) is not particularly limited, but is preferably 10 Å / min or more, more preferably 50 Å / min or more, and 100 Å / min or more in consideration of production efficiency. It is particularly preferred. Although there is no upper limit in particular, it is practical that it is 1000 kg / min or less.

  Although the exposed width of the metal layer is not particularly limited, it is preferably 2 nm or more, more preferably 4 nm or more, from the viewpoint that the advantages of the present invention become more prominent. Similarly, from the viewpoint of conspicuous effect, the upper limit is practically 1000 nm or less, preferably 100 nm or less, and more preferably 20 nm or less.

  The etching rate [R1] of the first layer (silicon layer or germanium layer) or the third layer (silicide layer) is not particularly limited, but is preferably not excessively removed, more preferably 100 Å / min or less, It is further preferably 60 Å / min or less, and particularly preferably 40 Å / min or less. There is no particular lower limit, but considering the measurement limit, it is practical that it is 0.1 Å / min or more.

  In the selective etching of the second layer and the third layer or the first layer, the etching rate ratio ([R2] / [R1]) is preferably 4 or more, more preferably 4.5 or more. Preferably, it is 5 or more, more preferably 5.5 or more. The upper limit is not particularly specified and is preferably as high as possible. However, it is practically 100 or less, 50 or less is more practical, and 15 or less is particularly practical.

Furthermore, in the etching solution according to a preferred embodiment of the present invention, a metal electrode layer such as Al or W, an insulating film such as HfO, HfSiO, WO, AlO _x , SiO ₂ , SiOC, SiON, SiOCN, TiN, SiN, or TiAlC Since damage to the layers (which may be collectively referred to as the fourth layer) can be suitably suppressed, it is also preferable to be applied to a semiconductor substrate including these layers. In addition, in this specification, when the composition of a metal compound is expressed by a combination of elements, it means that a composition having an arbitrary composition is widely included. For example, SiOC (SiON) means that Si, O, and C (N) coexist, and does not mean that the ratio of the amounts is 1: 1: 1. This is common in this specification, and the same applies to other metal compounds.

  The time required for etching one substrate is preferably 10 seconds or more, and more preferably 50 seconds or more. As an upper limit, it is preferable that it is 300 seconds or less, and it is more preferable that it is 200 seconds or less.

[Manufacture of semiconductor substrate products]
In this embodiment, a step of forming a semiconductor substrate on which a silicon layer and a metal layer are formed on a silicon wafer, a step of annealing the semiconductor substrate, an etchant is applied to the semiconductor substrate, and the etchant and the metal layer It is preferable to manufacture a semiconductor substrate product having a desired structure through a step of selectively removing the metal layer by bringing the metal layer into contact with each other. At this time, the specific etching solution is used for etching. The order of the above steps is not construed as being limited, and further steps may be included between the steps.
The wafer size is not particularly limited, but a wafer having a diameter of 8 inches, a diameter of 12 inches, or a diameter of 14 inches can be suitably used (1 inch = 25.4 mm).
In this specification, the term “preparation” means that a specific material is synthesized or blended, and a predetermined item is procured by purchase or the like. In this specification, using an etchant so as to etch each material of a semiconductor substrate is referred to as “application”, but the embodiment is not particularly limited. For example, the method widely includes contacting the etching solution with the substrate. Specifically, the etching solution may be immersed and etched in a batch type or may be etched by discharge in a single wafer type.
In this specification, the term “semiconductor substrate” is used to mean not only a wafer but also the entire substrate structure having a circuit structure formed thereon. A semiconductor substrate member refers to the member which comprises the semiconductor substrate defined above, and may consist of one material or may consist of several materials. A processed semiconductor substrate is sometimes referred to as a semiconductor substrate product, and is further distinguished as necessary, and a chip that has been processed and diced out and processed product thereof is referred to as a semiconductor element. That is, in a broad sense, a semiconductor element or a semiconductor product incorporating the semiconductor element belongs to a semiconductor substrate product.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to a following example. In addition, unless otherwise indicated,% and part shown as prescription and compounding quantity in an Example are mass references | standards.

[Example 1 and Comparative Example 1]
(Production of test substrate)
A Si film was epitaxially grown on a commercially available silicon substrate (diameter: 12 inches) and formed to a thickness of 500 mm (50 nm). Further, a Ti layer was formed on the Si epitaxial layer by CVD (chemical vapor deposition). This was annealed at 800 ° C. for 10 seconds to form a silicide layer to obtain a test substrate. The thickness of the silicide layer after annealing was 15 nm, and the thickness of the metal layer was 5 nm.
Similarly, blanket wafers in which other films were formed by CVD or the like were prepared. In the tests shown in the table below, the etching rate of each layer was measured using each of these test wafers.

(Etching test)
The blank wafer and the test substrate were etched using the single wafer type apparatus (SPS-Europe BV, POLOS (trade name)) under the following conditions, and an evaluation test was performed.
・ Processing temperature: 24 ° C. Room temperature ・ Discharge rate: 1 L / min.
-Wafer rotation speed: 500 rpm
・ Nozzle moving speed: 7cm / S
Note that the etching solution was supplied in one solution (using the A line in FIG. 3). Each treatment test was performed immediately after preparation.

(Measurement method of processing temperature)
A radiation thermometer IT-550F (trade name) manufactured by HORIBA, Ltd. was fixed at a height of 30 cm above the wafer in the single wafer type apparatus. A thermometer was directed onto the wafer surface 2 cm outside from the wafer center, and the temperature was measured while flowing a chemical solution. The temperature was digitally output from the radiation thermometer and recorded continuously with a personal computer. Among these, the value obtained by averaging the temperature for 10 seconds at which the temperature was stabilized was defined as the temperature on the wafer.

(Etching rate [ER])
About etching rate (ER), it computed by measuring the film thickness before and behind an etching process using ellipsometry (spectral ellipsometer, JA Woolum Japan Co., Ltd. Vase was used). An average value of 5 points was adopted (measurement condition measurement range: 1.2-2.5 eV, measurement angle: 70, 75 degrees). The measurement results of the etching rate of each layer are shown in the table below.

<Table notes>
DGMBE: Diethylene glycol monobutyl ether EGMBE: Ethylene glycol monobutyl ether EGMEE: Ethylene glycol monoethyl ether TiSi: Titanium silicon silicide Amount: parts by mass Component (A): Fluorine ion source Component (B): Water Component (C): Organic solvent ( Protic polar organic solvent)
Component (D): Substituted hydroquinone compound, etc.

<Measurement method of corrosion potential>
Apparatus: Princeton Applied Research company model 263A (trade name)
Substrate: Si substrate treated with 5% HF for 30 sec to remove the surface natural oxide film (P-type, 1-35 Ω · cm)
Corrosion potential was measured with a chemical solution of 5% by mass of H ₂ O + solvent (diethylene glycol monobutyl ether) + 0.1% by mass of NaClO ₄ + oxidizing agent 0.08 mol / kg.
Specifically, the corrosion potential was measured with a chemical solution in which 5% by mass of H ₂ O, the remainder of the solvent (diethylene glycol monobutyl ether), 0.1% by mass of NaClO ₄ and 0.08 mol / kg of oxidizing agent were mixed. Here, sodium perchlorate is added as a supporting electrolyte in the measurement in a solvent system. The measurement procedure was as follows.
1. A substrate (measurement material) subjected to a specific pretreatment is clipped as a working electrode.
2. Clip the Ag / AgCl reference electrode filled with a saturated KCl / AgCl solution as a reference electrode.
3. As a counter electrode, a counter electrode of platinum: TCE-1 manufactured by Princeton Applied Research is clipped.
4). Put the measurement solution into the cell.
5. Start measurement.
(1) Select Tafel plot in the linear sweep mode.
(2) Set to sweep at open circuit potential ± 0.5V.
6). Read the corrosion potential from the VI graph.

  As can be seen from the results in the above table, according to the etching solution of the present invention, it can be seen that the etching rate of Ti is high and the etching rate of the silicide layer (TiSi) can be kept low. In addition, it was confirmed that suitable protective properties could be realized for other metal compound materials applied to the semiconductor substrate.

1 Metal layer (second layer)
2 Silicon (silicon) or germanium-containing layer (first layer)
3 Silicide layer (third layer)
11 Processing container (processing tank)
12 Rotary table 13 Discharge port 14 Branch point S Substrate 21 Silicon substrate 22 Gate insulating film 23 Gate electrode 25 Side wall 26 Source electrode 27 Drain electrode 28 Ti film

Claims (20)

  An etching solution for a semiconductor process, which contains fluorine ions and a substituted hydroquinone compound.   Furthermore, the etching liquid of Claim 1 containing an organic solvent.   Furthermore, the etching liquid of Claim 1 or 2 containing water.   The etching solution according to any one of claims 1 to 3, wherein the concentration of the fluorine ions is 0.1 mass% or more and 20 mass% or less.   The etching liquid according to claim 1, wherein the concentration of the substituted hydroquinone compound is 0.1% by mass or more and 10% by mass or less.   The etching solution according to claim 2, wherein the concentration of the organic solvent is 50% by mass or more and 98% by mass or less.   The etching solution according to claim 3, wherein the concentration of water is 0.1 mass% or more and 50 mass% or less. The etching liquid according to any one of claims 1 to 7, wherein the substituted hydroquinone compound is represented by the following formula (H1).

R ^H1 represents a substituent. m1 represents an integer of 1 to 4. The etching solution according to claim 8, wherein R ^H1 is a hydrocarbon group. The etching solution according to claim 9, wherein R ^H1 is an alkyl group.   The ClogP value of the said substituted hydroquinone compound is 1-10, The etching liquid of any one of Claims 1-10.   The substituted hydroquinone compound is 2,5-di-tert-butylhydroquinone, 2-tert-butylhydroquinone, 2,5-dimethylhydroquinone, or 2-methylhydroquinone. Etching solution.   The etching solution according to any one of claims 1 to 12, wherein the corrosion potential of the substituted hydroquinone compound with respect to the silicon substrate is from -0.25 to 0.5.   The etching solution according to claim 2, wherein the organic solvent comprises an alcohol compound or an ether compound. The etching liquid according to claim 2, wherein the organic solvent comprises a compound represented by the following formula (O-1).

R ^O1 — (— O—R ^O2 —) _n —OR ^O3 (O-1)

R ^O1 and R ^O3 are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms.
R ^O2 is a linear or branched alkylene chain having 1 to 12 carbon atoms. When a plurality of R ^O2 are present, each of them may be different.
n is an integer of 0 or more and 12 or less. However, when n is 0, both R ^O1 and R ^O3 are not hydrogen atoms.   The etching liquid according to claim 1, wherein the semiconductor process substrate has a layer containing titanium and a layer containing titanium silicide.   The etching solution according to claim 16, wherein a value obtained by dividing the etching rate of the layer containing titanium by the etching rate of the layer containing titanium silicide is 4 or more and 15 or less.   The etching method which etches the layer containing titanium by applying the etching liquid of any one of Claims 1-17.   The etching method according to claim 18, wherein etching of the layer containing titanium is performed while suppressing etching of titanium silicide.   A method for manufacturing a semiconductor substrate product, wherein the semiconductor substrate product is manufactured through the etching method according to claim 18.

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