JP6425342B2 - Etching solution, etching method using the same, and method of manufacturing semiconductor substrate product - Google Patents

Description

  The present invention relates to an etching solution, an etching method using the same, and a method of manufacturing a semiconductor substrate product.

The manufacture of integrated circuits consists of a number of different processing steps. In the manufacturing process, deposition of various materials, lithography, etching and the like are repeated many times. Above all, etching is an important process. Certain materials should be selectively etched and others should be left without corrosion. In some cases, it is required to remove only predetermined layers in the form of leaving layers of similar metal species or layers of more corrosive materials. The size of interconnections and integrated circuits in semiconductor substrates is becoming smaller and smaller, and the importance of accurate etching without corroding members to be left is increasing.
Taking the field effect transistor as an example, with the rapid miniaturization thereof, thinning of a silicide layer formed on the upper surface of the source / drain region and development of a new material are strongly demanded. In a salicide process (Salicide: Self-Aligned Silicide) for forming this silicide layer, a part of source and drain regions made of silicon or the like formed on a semiconductor substrate and a metal layer attached to the upper surface are annealed. Thus, a low resistance silicide layer can be formed above the source / drain electrodes and the like.
After the salicide step, 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 using a chemical solution to which toluenesulfonic acid is added in addition to nitric acid and hydrochloric acid as a device for removing Ni and Pt. SC1 (NH ₄ / H ₂ O ₂ / H ₂ O mixed solution) is known as a silicide etchant of Ti.

International Publication No. 2012/125401 pamphlet

  An object of the present invention is to provide an etchant capable of removing titanium on a substrate. Furthermore, if necessary, an etching solution capable of selectively removing the layer containing titanium while suppressing damage to the layer containing silicon and / or germanium, particularly the silicide layer on the substrate, and etching using the same It aims at provision of a method and a manufacturing method of a semiconductor substrate. Furthermore, according to the requirements, an etching solution that achieves the above-mentioned good titanium removability while suppressing damage to each metal or composite compound layer applied to the production of semiconductor substrates such as W, TiN, TiAlC, etc. It is an object of the present invention to provide an etching method and a method for manufacturing a semiconductor substrate.

Ｒ ^Ｑ１ 〜Ｒ ^Ｑ６ はそれぞれ独立に置換基を表す。ｍ１は０〜４の整数を表す。ｍ２は０〜２の整数を表す。ｍ３は０〜４の整数を表す。ｍ４は０〜４の整数を表す。ｍ５は０〜４の整数を表す。ｍ６は０〜４の整数を表す。
〔２〕チタンとケイ素および／またはゲルマニウムとを含有する基板に適用してチタンを除去するエッチング液であって、
上記エッチング液はフッ素イオンと酸化剤とを含有し、上記酸化剤が、ｐ−ベンゾキノン、２，５−ジヒドロキシ−ｐ−ベンゾキノン、２−ヒドロキシ−ｐ−ベンゾキノン、テトラヒドロキシ−ｐ−ベンゾキノン、１，４−ナフトキノン、２−ヒドロキシ−１，４−ナフトキノン、２−メチル−ｐ−ベンゾキノン、２−メチル−１，４−ナフトキノン、２，５−ジメトキシ−１，４−ベンゾキノン、２，５−ジ−ｔｅｒｔ−ブチル−１，４−ナフトキノン、またはアリザリンであるエッチング液。
〔３〕上記エッチング液中、上記フッ素イオンの濃度が０．１質量％以上２０質量％以下である〔１〕または〔２〕に記載のエッチング液。
〔４〕上記エッチング液中、上記酸化剤の濃度が０．０００００１質量％以上１０質量％以下である〔１〕〜〔３〕のいずれか１つに記載のエッチング液。
〔５〕チタンとケイ素および／またはゲルマニウムとを含有する基板に適用してチタンを除去するエッチング液であって、
上記エッチング液はフッ素イオンと酸化剤とを含有し、上記酸化剤が、下記式（Ｑ１）〜（Ｑ４）のいずれかで表されるキノン系酸化剤であり、
上記エッチング液中、前記フッ素イオンの濃度が０．１質量％以上２０質量％以下、上記酸化剤の濃度が０．０１質量％以上２質量％以下であるエッチング液。

Ｒ ^Ｑ１ 〜Ｒ ^Ｑ６ はそれぞれ独立に置換基を表す。ｍ１は０〜４の整数を表す。ｍ２は０〜２の整数を表す。ｍ３は０〜４の整数を表す。ｍ４は０〜４の整数を表す。ｍ５は０〜４の整数を表す。ｍ６は０〜４の整数を表す。

〔６〕チタンとケイ素および／またはゲルマニウムとを含有する基板に適用してチタンを除去するエッチング液であって、
上記エッチング液はフッ素イオンと酸化剤とを含有し、上記酸化剤が、ｐ−ベンゾキノン、２，５−ジヒドロキシ−ｐ−ベンゾキノン、２−ヒドロキシ−ｐ−ベンゾキノン、テトラヒドロキシ−ｐ−ベンゾキノン、１，４−ナフトキノン、２−ヒドロキシ−１，４−ナフトキノン、２−メチル−ｐ−ベンゾキノン、２−メチル−１，４−ナフトキノン、２，５−ジメトキシ−１，４−ベンゾキノン、２，５−ジ−ｔｅｒｔ−ブチル−１，４−ナフトキノン、またはアリザリンであり、
上記エッチング液中、上記フッ素イオンの濃度が０．１質量％以上２０質量％以下、上記酸化剤の濃度が０．０１質量％以上２質量％以下であるエッチング液。
〔７〕さらに有機溶媒を含有する〔１〕〜〔６〕のいずれか１つに記載のエッチング液。
〔８〕さらに水を含有する〔１〕〜〔７〕のいずれか１つに記載のエッチング液。
〔９〕上記有機溶媒の濃度が５０質量％以上９９質量％以下である〔７〕に記載のエッチング液。
〔１０〕上記水の濃度が０．０１質量％以上３０質量％以下である〔８〕に記載のエッチング液。
〔１１〕上記有機溶媒が非プロトン性極性溶媒である〔７〕に記載のエッチング液。
〔１２〕上記有機溶媒が下記式（Ｏ−１）で表される化合物からなる〔７〕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、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は直鎖状または分岐状あるいは環状の炭素数１以上１２以下のアルキレン基である。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。
なお、Ｒ^Ｏ１〜Ｒ^Ｏ３はその２つ以上のものが連結して環構造を形成していてもよい。
〔１３〕チタンとケイ素および／またはゲルマニウムとを含有する基板に適用してチタンを除去するエッチング液であって、
上記エッチング液はフッ素イオンと酸化剤とを含有し、上記酸化剤がキノン系酸化剤、過塩素酸、過臭素酸、過ヨウ素酸、および硫酸からなる群から選ばれる少なくとも１種であり、
上記基板が、チタンを含む層とチタンシリサイドを含む層とを有し、
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、２．０以上１００以下であるエッチング液。
〔１４〕チタンとケイ素および／またはゲルマニウムとを含有する基板に適用してチタンを除去するエッチング方法であって、
上記エッチング方法は、フッ素イオンと酸化剤とを含有するエッチング液を基板に適用するものであり、
上記酸化剤が、下記式（Ｑ１）〜（Ｑ４）のいずれかで表されるキノン系酸化剤であるエッチング方法。

Ｒ ^Ｑ１ 〜Ｒ ^Ｑ６ はそれぞれ独立に置換基を表す。ｍ１は０〜４の整数を表す。ｍ２は０〜２の整数を表す。ｍ３は０〜４の整数を表す。ｍ４は０〜４の整数を表す。ｍ５は０〜４の整数を表す。ｍ６は０〜４の整数を表す。
〔１５〕チタンとケイ素および／またはゲルマニウムとを含有する基板に適用してチタンを除去するエッチング方法であって、
上記エッチング方法は、フッ素イオンと酸化剤とを含有するエッチング液を基板に適用するものであり、
上記酸化剤が、下記式（Ｑ１）〜（Ｑ４）のいずれかで表されるキノン系酸化剤であり、
上記エッチング液中、上記フッ素イオンの濃度が０．１質量％以上２０質量％以下、上記酸化剤の濃度が０．０１質量％以上２質量％以下であるエッチング方法。

Ｒ ^Ｑ１ 〜Ｒ ^Ｑ６ はそれぞれ独立に置換基を表す。ｍ１は０〜４の整数を表す。ｍ２は０〜２の整数を表す。ｍ３は０〜４の整数を表す。ｍ４は０〜４の整数を表す。ｍ５は０〜４の整数を表す。ｍ６は０〜４の整数を表す。
〔１６〕 〔１４〕または〔１５〕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 problems are solved by the following means.
[1] An etchant which is applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
The etching solution is a quinone-based oxidizing agent, wherein the etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is represented by any one of the following formulas (Q1) to (Q4) .

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4;
[2] An etchant which is applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, 2-hydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 1,1 4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methyl-p-benzoquinone, 2-methyl-1,4-naphthoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2,5-di- An etching solution which is tert-butyl-1,4-naphthoquinone or alizarin.
[3] In the above etching solution, the etching solution according to concentrations above Symbol fluoride ion is 20 wt% or less than 0.1 wt% [1] or [2].
[4] above in the etching solution, concentration of the upper Symbol oxidizing agent is not more than 10 wt% or more 0.000001 wt% (1) to the etching solution according to any one of [3].
[ 5 ] An etchant which is applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is a quinone-based oxidizing agent represented by any one of the following formulas (Q1) to (Q4) ,
In the etching solution, the concentration of the fluorine ion is 0.1% by mass to 20% by mass, and the concentration of the oxidizing agent is 0.01% by mass to 2% by mass.

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4;

[6] An etchant which is applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, 2-hydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 1,1 4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methyl-p-benzoquinone, 2-methyl-1,4-naphthoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2,5-di- tert-butyl-1,4-naphthoquinone or alizarin,
An etching solution in which the concentration of the fluorine ion is 0.1% by mass to 20% by mass and the concentration of the oxidizing agent is 0.01% by mass to 2% by mass in the etching solution.
[7] The etching solution according to any one of [1] to [6], further containing an organic solvent.
[8] The etching solution according to any one of [1] to [7], further containing water.
[9] The etching solution according to [7], wherein the concentration of the organic solvent is 50% by mass to 99% by mass.
[10] The etching solution according to [8], wherein the concentration of the water is 0.01% by mass to 30% by mass.
[11] The etching solution according to [7], wherein the organic solvent is an aprotic polar solvent.
[12] The etching solution according to [7], wherein the organic solvent is 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 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 ⁰² is a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms. When multiple R ^O2 are present, each may be different.
n is an integer of 0 or more and 12 or less.
Two or more of R ^{O1 to} R ^O3 may combine to form a ring structure.
[ 13 ] An etchant for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is at least one selected from the group consisting of quinone type oxidizing agents, perchloric acid, perbromic acid, periodic acid, and sulfuric acid,
The substrate has a layer containing titanium and a layer containing titanium silicide,
The etch rate of the layer containing the titanium, a value obtained by dividing the etching rate of the layer containing the titanium silicide, 2.0 or more to 100 or less der Rue etching liquid.
[ 14 ] An etching method for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
Upper Symbol etching method, the etching solution containing a fluorine ion and an oxidizing agent is intended to apply to the substrate,
Upper Symbol oxidizing agent, the etching method is quinone oxidizing agent represented by any one of the following formulas (Q1) ~ (Q4).

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4;
[ 15 ] An etching method applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
Upper Symbol etching method, the etching solution containing a fluorine ion and an oxidizing agent is intended to apply to the substrate,
Upper Symbol oxidizing agent is a quinone oxidizing agent represented by any one of the following formulas (Q1) ~ (Q4),
In the above SL etchant concentrations above Symbol fluorine ions 0.1 to 20 mass%, the etching method concentrations above Symbol oxidizing agent is not more than 2 wt% 0.01 wt%.

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4;
[ 16 ] The manufacturing method of the semiconductor substrate product which manufactures a semiconductor substrate product through the etching method as described in [ 14 ] or [ 15] .

  According to the etching solution of the present invention, the etching method using the same, and the method of manufacturing a semiconductor substrate product, titanium on the substrate can be removed. Furthermore, if necessary, damage to the layer containing silicon and / or germanium, particularly its silicide layer, on the substrate can be suppressed, and the layer containing titanium can be selectively removed. Furthermore, according to the present invention, damage to each metal or composite compound layer applied to the manufacture of semiconductor substrates such as W, TiN, TiAlC, etc. is suppressed according to the requirement, and the above-mentioned good titanium removability is realized. can do.

FIG. 7 is a cross-sectional view schematically showing an example of a manufacturing process of a semiconductor substrate in an embodiment of the present invention. FIG. 7 is a process drawing showing an example of manufacturing a MOS transistor according to an embodiment of the present 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 to the semiconductor substrate in one embodiment of the present invention.

  First, a preferred embodiment of the etching process according to the application of the etching solution of the present invention will be described based on FIG. 1 and FIG.

[Etching process]
FIG. 1 is a view showing a semiconductor substrate before and after etching. In the production example of the present embodiment, the metal layer (second layer) 1 is disposed on the top surface of the silicon and / or germanium-containing layer (first layer) 2. As a silicon and / 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 composed of Si or may be a SiGe or Ge epitaxial layer.

As a constituent material of the metal layer (second layer) 1, titanium (Ti), cobalt (Co), nickel (Ni), nickel platinum (NiPt), tantalum (Ta), niobium (Nb), tungsten (W), etc. And metal species (single metals or composite metals). Among them, titanium (Ti), nickel (Ni), and nickel platinum (NiPt) are preferable, and titanium (Ti) is more preferable, from the viewpoint that the effects of the present invention are significantly exhibited. The formation of a metal layer can use the method generally applied to formation of this kind of metal film, and, specifically, the film-forming by CVD (Chemical Vapor Deposition) is mentioned. The thickness of the metal layer at this time is not particularly limited, but an example of a film of 5 nm or more and 50 nm or less can be mentioned. In the present invention, when the metal layer is a Ti layer, it is preferable because the etching liquid removal performance is sufficiently exhibited.
The metal layer may contain other elements in addition to the metal atoms listed above. For example, oxygen and nitrogen which are inevitably mixed may be present. The amount of unavoidable impurities is preferably suppressed to, for example, about 1 ppt to 10 ppm (mass basis).
In addition to the above materials, there may be materials which are not desired to be etched in the semiconductor substrate. In the etching solution according to the preferred embodiment of the present invention, such corrosion of the material can be further suppressed, which is preferable.

  After the metal layer 1 is formed on the silicon and / or germanium-containing layer 2 in the above step (a), annealing (sintering) is performed to form a metal-Si reaction film (third layer: silicide) at the interface Layer 3 is formed (step (b)). Annealing may be carried out according to the conditions generally 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 an example in which the layer is 50 nm or less is mentioned, and further, an example in which the layer is 10 nm or less is mentioned. There is no particular lower limit, but it is practical to be 1 nm or more. The silicide layer is applied as a low resistance film, and functions as a conductive portion electrically connecting a source electrode and a drain electrode located in the lower portion thereof and a wiring disposed in the upper portion. Therefore, if a defect or corrosion occurs in the silicide layer, the conduction may be inhibited, which may lead to quality deterioration such as device malfunction. In particular, the integrated circuit structure inside the substrate has recently been miniaturized, and even minute damage can have a great impact on the performance of the device. Therefore, it is desirable that such defects and corrosion be prevented as much as possible.

  In the present specification, in a broad sense, the silicide layer is a concept included in the silicon- and / or germanium-containing layer of the first layer. Therefore, when selectively removing the second layer with respect to the first layer, only the aspect of preferentially removing the second layer (metal layer) with respect to the non-silicided silicon and / or germanium-containing layer In addition, it is a meaning including the aspect which removes the second layer (metal layer) preferentially to the silicide layer. In a narrow sense, when the first layer of silicon and / or germanium containing layer (excluding the silicide layer) and the third layer of silicide layer are distinguished, 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. Further, the term "silicide layer" is meant to include a composite metal layer formed by annealing each metal. Therefore, the term titanium silicide means not only silicides of titanium and silicon, but also silicides of titanium, silicon and germanium, and silicides of titanium and germanium. In the present invention, a silicide layer (TiSi) made of titanium and silicon, a silicide layer (TiGe) made of titanium and germanium, or a silicide layer (TiSiGe made of titanium, silicon, and germanium) from the viewpoint of the effect becoming remarkable. It is preferable to apply to the protection of) and more preferably to protect a silicide layer (TiSi) composed of titanium and silicon.

Next, etching of the remaining metal layer 1 is performed (step (b)-> step (c)). In this embodiment, an etching solution is applied at this time, and the metal layer 1 is removed by applying the etching solution from the upper side of the metal layer 1 and bringing the etching solution into contact. The form of application of the etching solution will be described later.
The silicon and / or germanium-containing layer 2 is made of Si and / or SiGe epitaxial layer, and can be formed by crystal growth on a silicon substrate having specific crystallinity by chemical vapor deposition (CVD) method. . Alternatively, it may be an epitaxial layer formed with desired crystallinity by electron beam epitaxy (MBE) method or the like.
In order to make the silicon- and / 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 be doped. In order to form an N-type layer, it is preferable that phosphorus (P) and arsenic (As) be 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, its 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 mass% of germanium, the layer formed with the alloy of the second layer by the annealing contains germanium and the specific metal element of the second layer and does not contain silicon, but as described above, the present specification In the text, for convenience, this is referred to as a germanium "silicide layer".
In the present specification, the concentration of germanium is a value measured by the following measurement method. The substrate of the layer containing germanium (Ge) is etched and the depth direction from 0 to 30 nm is analyzed with ESCA (Quanta made by ULVAC-PHI, Inc.), and the average value of Ge concentration in the analysis result of 3 to 15 nm is Ge concentration (mass%) I assume.

  Through the salicide step, the silicide layer is made of silicon (Si) or germanium (Ge) and a component of the second layer between the silicon and / or germanium containing layer (first layer) and the metal layer (second layer). It is formed as a layer containing (the above specific metal species). The silicide layer is included in the first layer in a broad sense, but when referred to in a narrow sense to distinguish it, it is referred to as a "third layer". The third layer is preferably 0.2 ≦ x + y ≦ 0.8 and 0.3 ≦ x + y ≦ 0.7, where x + y + z = 1, in the formula of SixGeyMz (M: metal element) Is more preferred. As for z, 0.2 ≦ z ≦ 0.8 is preferable, and 0.3 ≦ z ≦ 0.7 is more preferable. The preferable range of the ratio of x to y is preferably y = 0 (not including Ge), but in the case of containing Ge, it is as defined above. However, the third layer may contain other elements. That is the same as that described for the metal layer (second layer).

(Processing of MOS transistor)
FIG. 2 is a process chart showing an example of manufacturing a MOS transistor. (A) is a process of forming a MOS transistor structure, (B) is a sputtering process of a metal film, (C) is a first annealing process, (D) is a selective removal process of a metal film, and (E) is a second annealing process It is a process.
As shown in the figure, a gate electrode 23 is formed via a gate insulating film 22 formed on the surface of a 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) that prevents contact with the Ti layer may be formed on the upper side of the gate electrode 23. Furthermore, sidewalls 25 made of a silicon oxide film or a silicon nitride film are formed, and source regions 26 and drain regions 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, elements in the Ti film 28 are diffused into the silicon substrate to be silicided (herein, alloying by annealing is referred to as silicidation for convenience, including the case of 100 mass% of germanium). 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, as necessary, as shown in FIG. 2E, the electrode member is changed to a desired state (annealed silicide source electrode 26B, annealed silicide drain electrode 27B) by performing a second annealing. be able to. The first and second annealing temperatures are not particularly limited, but can be performed, for example, at 400 to 1100 ° C.

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

If the preferable example of a constituent material is given, the following forms can be illustrated.
21 Silicon substrate: Si, SiGe, Ge
22 Gate dielectric: HfO ₂ (High-k)
23 Gate electrode: Al, W
25 Sidewall: SiOCN, SiN, SiO ₂ (low-k), TiAlC
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 liquid of this invention is applied was mentioned above, it can apply not only to this specific example but another semiconductor substrate. For example, there is a semiconductor substrate including a high dielectric film / metal gate FinFET having a silicide pattern on source and / or drain regions.

  If it is difficult to remove only the upper metal layer (second layer) while leaving the silicide layer (third layer) to the layer (first layer) such as silicon, the silicide layer is removed. The point which is comprised including the metal which should be mentioned is mentioned. That is, if a solution component having high solubility is adopted to enhance the removability of the metal layer, the silicide layer containing the metal also tends to melt. In addition, when highly soluble components of metals (Ti, Pt, Ni, etc.) that form silicides are applied, they are generally soluble in silicon (Si) and germanium (Ge) as seen from the order of their ionization tendency. In the direction of Therefore, while improving the solubility of the metal layer, suppressing the damage of the silicide layer on the other hand is in the opposite direction. According to a preferred embodiment of the present invention, such incompatible characteristics are realized to protect the silicide layer desired to be left as a semiconductor substrate product and to effectively remove the metal layer on the upper side etc. it can.

[Etching solution]
Next, a preferred embodiment of the etching solution of the present invention will be described. The etching solution of the present embodiment contains a fluorine ion and an oxidizing agent. Furthermore, if necessary, an organic solvent or water may be contained. Each component will be described below.

(Fluorine ion)
The etching solution of the present invention contains fluorine ions. The fluorine ion is considered to play a role of promoting the dissolution by becoming a ligand (complexing agent) of the metal (Ti or the like) of the second layer in the etching solution.
The concentration of the fluorine ion 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 more preferable, 2 mass% or less is especially preferable. It is preferable to apply fluorine ions at the above-mentioned concentration, as it is possible to realize effective etching of a layer of silicon or germanium or a silicide layer thereof while achieving good etching of a 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. The fluorine-containing compound may be used alone or in combination of two or more. As a source of fluoride ions, hydrofluoric acid (HF) is preferred.

(Oxidant)
The oxidizing agent used in the present invention is preferably at least one selected from the group consisting of quinone type oxidizing agents, perhalogen acids (perchloric acids, perbromic acids, periodic acids, etc.), and sulfuric acid, Among them, quinone type oxidizing agents are preferable. The above-mentioned quinone type oxidizing agent is the meaning which includes the compound which has a benzoquinone frame widely. In the etching solution of the present invention, it is understood that the oxidizing agent cooperated with the above-mentioned fluorine ion to achieve proper metal removability and protection of the silicon to germanium containing layer (preferably its silicide layer). First of all, it is considered that the oxidizing agent forms a chelate with the metal to promote its dissolution. The dissolution of metal by fluoride ion is very high in its activity and difficult to control, but it is considered that its controllability is enhanced by the interaction with the formation of a chelate as described above. . On the other hand, it is considered that the oxidizing agent forms an oxide film on the surface of the silicon-germanium-containing layer (preferably, the silicide layer thereof) and exhibits the same effect as forming the passive state. As a result, it is understood that they exhibit good protection to these layers.

It is preferable that the said quinone type oxidizing agent consists of a compound represented by either of following formula (Q1)-(Q4).

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. As a substituent, an alkyl group (carbon number 1 to 12 is preferable, 1 to 6 is more preferable, 1 to 4 is particularly preferable), an alkenyl group (carbon number 2 to 12 is preferable, 2 to 6 is more preferable), Aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 and particularly preferably 6 to 10), aralkyl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 and particularly preferably 6 to 10) ), Alkoxy group (1 to 12 carbon atoms are preferable, 1 to 6 is more preferable, and 1 to 3 are particularly preferable), hydroxyl group-containing group, carboxyl group-containing group, thiol group (sulfanyl group) -containing group, amino group-containing group A group (the carbon number of the amino group is preferably 0 to 6, more preferably 0 to 3), and a halogen atom (such as chlorine or bromine) is preferable. Among them, an alkyl group, an alkoxy group, a hydroxyl group-containing group and a halogen atom are preferable. It is preferable that the hydroxyl group-containing group, the carboxyl group-containing group, the thiol group-containing group, and the linking group of the amino group-containing group have no form (single bond). When the linking group is contained, the linking group is an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 and particularly preferably 1 to 3), and an alkenylene group (preferably having 2 to 12 carbon atoms, 2 to 6) Is more preferred), O, CO, NR ^N , S, or a combination thereof. 1-12 are preferable except the hydrogen atom, as for the number of the atoms which comprise a coupling group, 1-6 are more preferable, and 1-3 are especially preferable. 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 means the minimum number of atoms involved in connection, which is located in a path connecting predetermined structural parts. For example, in the case of —CH ₂ —C (OO) —O—, the number of atoms constituting the linking group is 6, but the number of linking atoms is 3.
In formula (Q3), it is preferable that R ^Q4 and R ^Q5 be a hydroxyl group.
When R ^{Q1 to} R ^Q6 are an alkyl group, an alkenyl group or the like, they may be linear, branched or cyclic. Further, adjacent to each other in R ^{Q1 to} R ^Q6 may be bonded or condensed to form a ring. The ring formed is preferably a 5- to 7-membered ring. Among them, a 5- to 7-membered hydrocarbon ring is preferable. For example, a cyclohexane ring, a benzene ring and the like can be mentioned.

m1 represents an integer of 0 to 4, an integer of 0 to 2 is preferable, and 0 or 1 is preferable.
m2 represents an integer of 0 to 2, preferably 0 or 1.
m3 represents an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably 0 or 1.
m4 represents an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably 0 or 1.
m5 represents an integer of 1 to 4 and is preferably an integer of 1 to 2;
m6 represents an integer of 0 to 4, an integer of 0 to 2 is preferable, and 0 or 1 is preferable.

  Specific examples of the above-mentioned quinone type oxidizing agent include p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, 2-hydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 1,4-naphthoquinone, 2-hydroxy- 1,4-naphthoquinone, 2-methyl-p-benzoquinone, 2-methyl-1,4-naphthoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2,5-di-tert-butyl-1,4- Naphthoquinone or alizarin is preferred.

In the present invention, the concentration of the oxidizing agent in the etching solution is preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less, and 3% by mass or less Is particularly preferred. Furthermore, when it mix | blends with a small amount, it is preferable that it is 2 mass% or less, It is more preferable that it is 1 mass% or less, It is especially preferable that it is 0.5 mass% or less. As a lower limit, 0.000001 mass% or more is preferable, 0.00001 mass% or more is more preferable, 0.0001 mass% or more is more preferable, 0.001 mass% or more is more preferable, 0.01 mass% or more is more preferable. Particularly preferred. Since the oxidizing agent exhibits the dissolving action of the metal layer, the more it is added, the higher its solubility. On the other hand, when the protection of the silicide layer is considered, it is preferable to set the above range. In particular, in order to protect the silicide layer while dissolving the metal layer in expectation of an interaction with the fluorine ion, it is preferable to set the concentration range as described above.
The above oxidizing agents may be used alone or in combination of two or more. When two or more types are used in combination, the combined use ratio is not particularly limited, but the total amount used is preferably the above concentration range as a total of two or more types.

(Organic solvent)
The etching solution according to the present invention may contain an organic solvent. The organic solvent is preferably an aprotic polar organic solvent. Examples of the aprotic polar organic solvent include halogenated hydrocarbon compounds, ether compounds, ester compounds, ketone compounds, nitrile compounds, amide compounds and sulfoxide compounds. Among them, ether compounds (having 1 to 36 carbon atoms are preferable, 2 to 24 carbon atoms are more preferable, 4 to 18 carbon atoms are more preferable, and 4 to 12 carbon atoms are particularly preferable) are preferable. Although the reason why the ether compound is preferable includes unclear points, not only a simple solvation suppressing effect but also an action by adsorption on the substrate surface is considered. From this point of view, the ether-terminated organic group (R of -O-R) preferably has a small number of carbon atoms, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
・ Halogenated hydrocarbon compounds Methylene chloride, chloroform, dichloromethane, ethane chloride, carbon tetrachloride, trichloroethylene, tetrachloroethylene, epichlorohydrin, monochlorobenzene, ortho dichlorobenzene, allyl chloride, HCFC, methyl monochloroacetate, ethyl monochloroacetate, monochloromethane Trichloroacetic acid, methyl bromide, methyl iodide, tri (tetra) chloroethyle etc. · Ether compounds dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, t-butyl methyl ether, cyclohexyl methyl ether, anisole, tetrahydrofuran, tetrahydropyran ( Poly) alkylene glycol monoalkyl ether (diethylene glycol monomethyl ether, diethylene glycol Monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, etc., (poly) alkylene glycol dialkyl ether (ethylene) Glycol dimethyl ether (1,2-dimethoxyethane), ethylene glycol dibutyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether , Diethylene glycol dibutyl ether, dipropylene glycol dibutyl ether etc. Among them, highly hydrophilic methyl-terminated ether is particularly effective, and 1,2-dimethoxyethane or tetraethylene glycol dimethyl ether is particularly preferable.
・ Ester compounds Ethyl acetate, ethyl lactate, 2- (1-methoxy) propyl acetate, methyl 3-methoxy-propionate, propylene glycol monomethyl ether acetate etc. ・ Ketone compounds Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 2-heptanone etc Nitrile compounds Acetonitrile, etc. Amide compounds N, N-dimethylformamide, 1-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidinone, ε-caprolactam, formamide, N -Methylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropanamide, hexamethylphosphoric triamide, etc. Sulfoxide compounds Methyl sulfoxide etc

Among them, 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 each independently represent a hydrogen atom, an alkyl group having 1 to 12 (preferably 1 to 6, more preferably 1 to 3) carbon atoms, or an aryl group having 6 to 14 (preferably 6 to 10) carbon atoms Or an aralkyl group having 7 to 15 (preferably 7 to 11) carbon atoms. Among them, one of R ^O1 and R ^O3 is preferably an alkyl group, and it is more preferable that both R ^O1 and R ^O3 be an alkyl group (particularly a methyl group). R ^O1 and R ^O3 may be linear or branched, or may be cyclic.
・ R ^O2
R ⁰² is a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms. When multiple R ^O2 are present, each may be different. R ^O2 is preferably 2 to 10 carbon atoms, more preferably 2 to 6, 2 to 4 are particularly preferred.
N
n is an integer of 0 or more and 12 or less, preferably 0 or more and 6 or less. When n is 2 or more, the plurality of R ⁰² may be different from each other. When n is 0, neither R ^O1 nor R ^O3 is a hydrogen atom.
Two or more of R ^{O1 to} R ^O3 may combine to form a ring structure.

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 96% by mass or less Particularly preferred. As a lower limit, 50 mass% or more is preferable, 60 mass% or more is more preferable, 70 mass% or more is more preferable, 80 mass% or more is more preferable, 90 mass% or more is particularly preferable. By setting the organic solvent in the above range, the concentration of water can be reduced, and damage to the silicon or germanium layer, the silicide layer thereof, and the like can be effectively suppressed, which is preferable. On the other hand, it is preferable to select the type and the amount to promote the interaction between the above-mentioned fluorine ion and the oxidizing agent and maintain the good etching property of the metal layer (second layer).
In the present invention, only one organic solvent may be used, or two or more organic solvents may be used in combination. When two or more types are used in combination, the combined use ratio is not particularly limited, but the total amount used is preferably the above concentration range as a total of two or more types.

In the present specification, when the compound or the substituent / linking group or the like contains an alkyl group / alkylene group, an alkenyl group / alkenylene group, an alkynyl group / alkynylene group or the like, these may be cyclic or linear, and may be linear or branched. And may be substituted or unsubstituted with any group. 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 And may form a ring structure. When the aryl group, the heterocyclic group and the like are contained, they may be monocyclic or fused ring, and may be substituted or unsubstituted as well.
The above R ^N is a hydrogen atom or a substituent. As a substituent, an alkyl group (carbon number 1 to 24 is preferable, 1 to 12 is more preferable, 1 to 6 is more preferable, and 1 to 3 is particularly preferable), an alkenyl group (carbon number 2 to 24 is preferable, 2 To 12 are more preferable, 2 to 6 is more preferable, and 2 to 3 are particularly preferable, and an alkynyl group (having 2 to 24 carbon atoms is preferable, 2 to 12 is more preferable, 2 to 6 is more preferable, and 2 to 3 Particularly preferred is an aryl group having 6 to 10 carbon atoms and an aralkyl group having 7 to 11 carbon atoms.
In the present specification, various technical matters such as temperature and thickness can be combined with each other even if the list is individually described, including choices of substituents and linking groups of the compound.
In the present specification, when a compound or an acid is added at the end to specify a compound, or when a compound is specified as an oxidizing agent or the like, ions thereof, in addition to the corresponding compound, within the range where the effects of the present invention are exhibited. It is a meaning including salt. Also, in the same way, it is meant to include its derivatives.

(water)
Water (water medium) is preferably contained in the etching solution of the present invention. The water (water medium) may be an aqueous medium containing a dissolution component as long as the effect of the present invention is not impaired, or may contain an unavoidable minor mixing component. Among them, water subjected to purification treatment such as distilled water, ion exchange water, or ultrapure water is preferable, and it is particularly preferable to use ultrapure water used for semiconductor production. The concentration of water is not particularly limited, but it is preferably 0.01% by mass or more, preferably 0.1% by mass or more, and particularly preferably 1% by mass or more in the etching solution. The upper limit is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 15% by mass or less, still more preferably 10% by mass or less, and 5% by mass It is particularly preferred that
In the present invention, the concentration of water in the etching solution is preferably defined in a predetermined range. In the absence of water, the etching action of the metal layer may not be sufficiently exhibited. Although application to this point is preferable, suppressing this amount to an appropriate amount is preferable because damage to the silicon or germanium layer, the silicide layer and the metal layer to be protected can be suppressed.

(Polymer compound)
A polymer compound may be contained in the etching solution of the present invention in addition to the above-mentioned basic component. The polymer compound is not particularly limited, but is preferably a water-soluble polymer compound which is uniformly dispersed or dissolved in an aqueous medium, and more preferably one which is uniformly dissolved at a predetermined content. Specifically, polyalkylene glycol (polyethylene glycol, polypropylene glycol), polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylic acid, polyethylene imine, polyphenol, or polyallylamine can be mentioned. Among them, polyethylene glycol, polypropylene glycol and polyvinyl alcohol are preferable. The molecular weight of the polymer compound is not particularly limited, but is preferably 400 to 300,000, and more preferably 5,000 to 90,000.
In the present specification, unless otherwise specified, the molecular weight is a value measured using GPC (gel filtration chromatography) method, and the molecular weight is a polystyrene-equivalent weight average molecular weight.

  The above-described polymer compounds can be used singly or in combination of two or more. The polymer compound is preferably added between 3 and 0.000001% by mass, more preferably 1 to 0.000001% by mass, and further preferably 0.1 to 0 based on the total mass of the etching solution. .0001% by mass is added.

(Surfactant)
The etching solution of the present invention may contain a surfactant. The surfactant is not particularly limited, but an anionic surfactant, a cationic surfactant, a nonionic surfactant, a surfactant comprising a polymer compound, a fluorine-based surfactant, a polyoxyalkylene-based surfactant Etc. can be applied as appropriate. Among them, anionic surfactants are preferable, and fatty acids (such as lauric acid) are more preferable.
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 based on 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. The surfactant may be used alone or in combination of two or more.

(PH adjuster)
In the etching solution of the present invention, a pH adjuster may be used. As pH adjusters, use is made of quaternary ammonium salts such as tetramethyl ammonium and choline, alkali hydroxides or alkaline earth salts such as potassium hydroxide, and amino compounds such as 2-aminoethanol and guanidine 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 and 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 Acids, succinic acids, glutaric acids, adipic acids, pimelic acids, maleic acids, phthalic acids, malic acids, tartaric acids, citric acids, lactic acids and the like can be mentioned.
The amount of use of the pH adjuster is not particularly limited, and may be used in an amount necessary to adjust the pH to the above range. The pH adjusters may be used alone or in combination of two or more.

(Corrosion potential)
The etching solution of the present invention preferably has its corrosion potential adjusted. Specifically, the corrosion potential as defined by the measurement method presented in the examples below is preferably -0.2 V or more, more preferably -0.18 V or more, and -0.15 V or more More preferably, -0.1 V or more is more preferable, 0 V or more is more preferable, and 0.1 V or more is particularly preferable. As an upper limit, 1.0 V or less is preferable, and 0.5 V or less is more preferable. In addition, the measuring method of a corrosion potential follows the procedure employ | adopted by the postscript Example.

(container)
The etching solution of the present invention can be stored, transported, and used in any container, as long as corrosion and the like (whether or not it is a kit) do not matter. In addition, for semiconductor applications, it is preferable that the container has high cleanliness and less elution of impurities. Usable containers include, but are not limited to, “Clean Bottle” series manufactured by Icero Chemical Co., Ltd., “Pure Bottle” manufactured by Kodama Resin Industry Co., Ltd., and the like.

[Etching conditions]
As an application example of the etching solution, an embodiment is preferable in which the etching solution is adjusted and then applied to the etching process in a timely manner. By doing so, it is possible to effectively exhibit a desired etching action without causing deterioration in liquid performance due to the decomposition of each component. Here, “timely” after mixing refers to a time after mixing until the desired action is lost, and specifically, it is preferably within 60 minutes, more preferably within 30 minutes, and 10 minutes. It is more preferably within the range, and particularly preferably within 1 minute. There is no particular lower limit, but it is practical to be 1 second or more.

  If it demonstrates using FIG. 3, the prepared etching liquid will be injected from the discharge port 13, and will be applied to the upper surface of the semiconductor substrate S in the processing container (processing tank) 11. As shown in FIG. In the embodiment shown in the figure, a chemical solution is supplied from A, and it is made to shift to the discharge port 13 via the branch point 14 and the flow path fc. The flow path fd indicates a return path for reusing the drug solution. It is preferable that the semiconductor substrate S be on the turntable 12 and be rotated together with the turntable by the rotation drive unit M. The branch point 14 is an example of a switching valve, and processing can be performed by switching between supply and return of the chemical solution. Alternatively, a valve that can adjust the flow direction may be applied to make this happen simultaneously.

In addition, it is preferable that the etching liquid of this invention has few impurities, for example, a metal part, etc. in a liquid in view of the use application. In particular, it is preferable that the concentration of Na, K, and Ca ions in the solution is in the range of 1 ppt to 1 ppm (mass basis). In the etching solution, the number of coarse particles having an average particle diameter of 0.5 μm or more is preferably in the range of 100 particles / cm ³ or less, and more 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 processing apparatus has a processing tank, transports or rotates the semiconductor substrate in the processing tank, applies (ejects, jets, flows down, drops, etc.) the etching solution in the processing tank. Preferably, the etching solution is brought into contact with the semiconductor substrate.
The merits of the single-wafer apparatus include (i) good reproducibility and (ii) high in-plane uniformity because fresh etchant is always supplied. It is preferable that the control temperature when performing the temperature control of the line be in the same range as the post treatment temperature.
The single wafer type apparatus preferably has a nozzle in its processing tank, and the method of swinging the nozzle in the surface direction of the semiconductor substrate and discharging the etching solution onto the semiconductor substrate is preferable. By doing so, deterioration of the solution can be prevented, which is preferable. In addition, it is possible to make it difficult to generate gas and the like by dividing into two or more solutions in a kit, which is preferable.

The processing temperature at which the etching is performed is preferably 5 ° C. or more, and more preferably 15 ° C. or more. The upper limit is preferably 50 ° C. or less, more preferably 40 ° C. or less, and still more preferably 30 ° C. or less. By setting it as the said lower limit or more, sufficient etching rate with respect to a 2nd layer can be ensured, and it is preferable. By setting the above upper limit value or less, the temporal stability of the etching process rate can be maintained, which is preferable. In addition, the ability to process at around room temperature leads to a reduction in energy consumption.
In addition, although the processing temperature of etching is based on the temperature applied to the substrate in the temperature measurement method shown in the examples described later, when it is controlled by storage temperature or batch processing, it is controlled by the temperature in the tank and circulation system. In this case, the temperature may be set within the circulation channel.

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

In the single-wafer etching according to the preferred embodiment of the present invention, it is preferable to transport or rotate the semiconductor substrate in a predetermined direction, and to spray the etchant into the space to bring the etchant into contact with the semiconductor substrate. . The supply speed of the etching solution and the rotation speed of the substrate are the same as described above.
In the sheet-fed apparatus configuration according to the 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 applying the etching solution to the semiconductor substrate S, the substrate is rotated in the r direction. On the other hand, the discharge port is moved along a movement trajectory line t extending from the center to the end of the semiconductor substrate. As described above, in the present embodiment, the rotation direction of the substrate and the movement direction of the discharge port are set to be different from each other, whereby the both move relative to each other. As a result, the etching solution can be uniformly applied to the entire surface of the semiconductor substrate, and the uniformity of the etching can be suitably secured.
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 thereof is preferably 30 cm / s or less, more preferably 15 cm / s or less. The movement locus line may be a straight line or a curved line (for example, an arc shape). In any case, the moving speed can be calculated from the actual distance of the trajectory and the time spent for the movement. The time required to etch 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 more preferably 100 Å / min or more in consideration of production efficiency. Is particularly preferred. There is no particular upper limit, but it is practical that it is 1000 Å / min or less.

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

  Although the etching rate [R1] of the first layer (silicon layer and / or germanium layer) or the third layer (silicide layer) is not particularly limited, it is preferable not to be removed excessively, and it is further preferably 100 Å / min or less Preferably, it is 60 Å / min or less, more preferably 50 Å / min or less. There is no particular lower limit, but it is practical to be 0.01 Å / min or more in consideration of the measurement limit.

  In the selective etching of the second layer and the first layer and / or the third layer, the etching rate ratio ([R2] / [R1]) is preferably 2.0 or more, more preferably 3.0 or more, 4.0 or more is further preferable, 5.0 or more is further preferable, 6.0 or more is further preferable, and 7.0 or more is particularly preferable. The upper limit is not particularly defined, and is preferably as high as possible, but it is practical that it is 1000 or less, and it is more practical that it is 100 or less.

Furthermore, in the etching solution according to the preferred embodiment of the present invention, metal electrode layers such as Al and W, HfO, HfSiO, WO, AlO _x , SiO ₂ , SiO ₂ , SiOC, SiN, SiON, SiOCN, TiN, SiN, TiAlC, etc. Since damage to the insulating film layer (these may be collectively referred to as the fourth layer) can be suitably suppressed, it is also preferable to be applied to a semiconductor substrate containing these. In addition, in this specification, when the composition of a metal compound is described by the combination of the element, it is the meaning which includes widely the thing of arbitrary compositions. 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 to the present specification, and the same applies to other metal compounds.

  The etching rate [R4] of the fourth layer is not particularly limited, but is preferably not removed excessively, more preferably 40 Å / min or less, still more preferably 20 Å / min or less, and 10 Å / min or less Is particularly preferred. There is no particular lower limit, but it is practical to be 0.01 Å / min or more in consideration of the measurement limit.

  In the selective etching of the fourth layer and the first layer and / or the third layer, the etching rate ratio ([R4] / [R1]) is preferably 2.0 or more, more preferably 3.0 or more, 4.0 or more is further preferable, 5.0 or more is further preferable, 6.0 or more is further preferable, and 7.0 or more is particularly preferable. The upper limit is not particularly defined, and is preferably as high as possible, but it is practical that it is 1000 or less, and it is more practical that it is 100 or less.

  The time required to etch one substrate is preferably 10 seconds or more, and more preferably 50 seconds or more. The upper limit is preferably 300 seconds or less, more preferably 200 seconds or less.

[Manufacturing of semiconductor substrate products]
In the present embodiment, a step of forming a semiconductor substrate in which the silicon layer and the metal layer are formed on a silicon wafer, a step of annealing the semiconductor substrate, an etchant is applied to the semiconductor substrate, and an etchant and metal layer And selectively removing the metal layer to produce a semiconductor substrate product having a desired structure. At this time, the above-mentioned specific etching solution is used for the etching. The order of the above steps is not to be interpreted as being limited, and additional steps may be included between the respective steps.
The wafer size is not particularly limited, but one having 8 inches in diameter, 12 inches in diameter, or 14 inches in diameter can be suitably used (1 inch = 25.4 mm).
The term "preparation" as used in the present specification is meant to include procuring a predetermined material by purchasing or the like, in addition to providing a specific material by synthesis or preparation. Moreover, in this specification, although using an etching liquid to etch each material of a semiconductor substrate is called "application", the embodiment is not specifically limited. For example, the method broadly includes contacting an etching solution with a substrate, and specifically, it may be immersed and etched in a batch type, or may be etched by discharge in a single wafer type.
In the present specification, the term "semiconductor substrate" is used to mean not only a wafer but also the entire substrate structure on which a circuit structure is formed. The semiconductor substrate member refers to a member constituting the semiconductor substrate defined above, and may be made of one material or a plurality of materials. In addition, the processed semiconductor substrate may be distinguished and called as a semiconductor substrate product, and if necessary, it may be further distinguished, processed and diced and taken out and a processed product thereof will be called a semiconductor element. That is, in a broad sense, semiconductor elements and semiconductor products incorporating them belong to semiconductor substrate products.

  EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples. In the examples,% and parts shown as formulation and amount are based on mass unless otherwise specified.

Example 1 Comparative Example 1
(Preparation of test substrate)
A Si film was epitaxially grown on a commercially available silicon substrate (diameter: 12 inches) to a thickness of 200 Å (20 nm). Furthermore, a layer of Ti was formed by the CVD method on the above-mentioned Si epitaxial layer. 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 5 nm, and the thickness of the metal layer was 15 nm.
Similarly, other films were also prepared as blanket wafers prepared by CVD or the like. In the tests in the following table, the etching rate of each layer was measured using each of these test wafers.

(Etching test)
The above-mentioned blank wafer and test substrate were etched in a single-wafer apparatus (SPOS-Europe B.V., POLOS (trade name)) under the following conditions, and an evaluation test was conducted.
Processing temperature: 24 ° C. Room temperature Discharge amount: 1 L / min.
Wafer rotational speed: 500 rpm
・ Nozzle movement speed: 7 cm / S
In addition, supply of the etching liquid was performed by 1 liquid (A line of FIG. 3 is used). 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 the wafer center, and the temperature was measured while flowing the chemical solution. The temperature was digitally output from a radiation thermometer and continuously recorded on a personal computer. Among these values, the value obtained by averaging the temperature for 10 seconds at which the temperature was stabilized was taken as the temperature on the wafer.

(Etching rate [ER])
The etching rate (ER) was calculated by measuring the film thickness before and after the etching process using ellipsometry (spectrometric ellipsometer, using V-Aurum Japan Ltd. Vase). The 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 following table.

<Table annotations>
TiSi: titanium silicon silicide Blending amount: parts by mass Component (A): Fluorine ion source Component (B): Water Component (C): Organic solvent (aprotic polar organic solvent)
Component (D): Oxidizing agent What is minus (-) in the etching rate is considered to be due to measurement error. It can be evaluated that it is almost unetched (damaged).
Polypropylene glycol: molecular weight 3000

  As can be seen from the results in the above table, according to the etching solution of the present invention, the etching rate of Ti is high, and the etching rate of the silicide layer (TiSi) can be suppressed to a low level. In addition, it has been confirmed that suitable protection can be realized for each of the other metal compound materials applied to the semiconductor substrate.

The above test No. The results of measuring the corrosion potential for 103, 105, 106, 109, 110, c01 were as follows. It can be seen that good performance is exhibited when the corrosion potential exceeds a predetermined value.
――――――――――――――――
Test No. Corrosion potential----------
103 0.19
105-0.04
106 0.29
109 0.13
110 0.10
c01-0.18
――――――――――――――――

<Method of measuring corrosion potential>
Equipment: Princeton Applied Research Inc. model 263A (trade name)
Substrate: Si substrate (P-type, 1 to 35 Ω · cm) from which natural oxide film on the surface was removed by treatment with 5% HF for 30 seconds
The corrosion potential was measured with a chemical solution of H ₂ O 5% by mass + solvent (tetraethylene glycol dimethyl ether) + NaClO ₄ 0.1% by mass + 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 balance of solvent (tetraethylene glycol dimethyl ether), 0.1% by mass of NaClO ₄ , and 0.08 mol / kg of an oxidizing agent were mixed. . Here, sodium perchlorate is added as a supporting electrolyte in measurement in a solvent system. The measurement procedure was as follows.
1. The substrate (measurement material) subjected to the specific pretreatment as a working electrode is clipped.
2. Clip the Ag / AgCl reference electrode filled with saturated KCl / AgCl solution as a reference electrode (Reference electrode).
3. A platinum counter electrode as a counter electrode (Counter electrode): TCE-1 manufactured by Princeton Applied Research Inc. 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. The corrosion potential is read from the VI graph.

Example 2
No. In the test of 101, the oxidizing agent used is replaced with 2-hydroxy-naphthoquinone, and alizarin, 2,5-dihydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 2,5-dihydroxy-1,4-benzoquinone, Similar experiments were performed using 2,5-di-tert-butyl-1,4 naphthoquinone respectively. As a result, it was confirmed that good etching selectivity was observed, and a sufficient Ti / TiSi selectivity was exhibited.

[Example 3]
No. In the test of 101, the amount of HF was changed to 1 part, 3 parts, 5 parts respectively, and the same experiment was performed. The HF increment was controlled by reducing the amount of aprotic polar organic solvent. As a result, it was confirmed that good etching selectivity was observed, and a sufficient Ti / TiSi selectivity was exhibited.

1 Metal layer (second layer)
2 Silicon (silicon) or germanium containing layer (first layer)
3 Silicide layer (third layer)
11 treatment container (treatment 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 (16)

An etchant for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
The etchant contains a fluoride ion and an oxidizing agent, said oxidizing agent, the etching solution is a quinone oxidizing agent represented by any one of the following formulas (Q1) ~ (Q4).

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4; An etchant for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent includes p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, 2-hydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 1, 4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methyl-p-benzoquinone, 2-methyl-1,4-naphthoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2,5-di- tert- butyl-1,4-naphthoquinone or alizarine der Rue etching liquid. Wherein the etching solution, the etching solution according to claim 1 or 2 concentration of the fluorine ion is 20 wt% or less than 0.1 wt%. The etching solution according to any one of claims 1 to 3 , wherein a concentration of the oxidizing agent is 0.000001% by mass or more and 10% by mass or less in the etching solution. An etchant for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
The etchant contains a fluorine ion oxidizing agent, said oxidizing agent is a quinone oxidizing agent represented by any one of the following formulas (Q1) ~ (Q4),
The etching liquid whose concentration of the said fluorine ion is 0.1 mass% or more and 20 mass% or less, and whose density | concentration of the said oxidizing agent is 0.01 mass% or more and 2 mass% or less in the said etching liquid.

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4; An etchant for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, 2-hydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 1,1 4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methyl-p-benzoquinone, 2-methyl-1,4-naphthoquinone, 2,5-dimethoxy-1,4-benzoquinone, 2,5-di- tert-butyl-1,4-naphthoquinone or alizarin,
The etching liquid whose concentration of the said fluorine ion is 0.1 mass% or more and 20 mass% or less, and whose density | concentration of the said oxidizing agent is 0.01 mass% or more and 2 mass% or less in the said etching liquid.   The etching solution according to any one of claims 1 to 6, further comprising an organic solvent.   Furthermore, the etching liquid of any one of Claims 1-7 containing water. The etching solution according to claim 7 concentration before Symbol organic solvent is less than 50 mass% to 99 mass%. Etching solution according to claim 8 concentration before Symbol water is 30 wt% or less than 0.01 mass%. The etching solution according to claim 7 before Symbol organic solvent is an aprotic polar solvent. The etching solution according to claim 7 before Symbol organic solvent comprising 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 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 ⁰² is a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms. When multiple R ^O2 are present, each may be different.
n is an integer of 0 or more and 12 or less.
Two or more of R ^{O1 to} R ^O3 may combine to form a ring structure. An etchant for removing titanium by applying it to a substrate containing titanium and silicon and / or germanium,
The etching solution contains a fluorine ion and an oxidizing agent, and the oxidizing agent is at least one selected from the group consisting of a quinone based oxidizing agent, perchloric acid, perbromic acid, periodic acid, and sulfuric acid,
The substrate has a layer containing titanium and a layer containing titanium silicide,
Before Symbol etch rate of the layer containing titanium, a value obtained by dividing the etching rate of the layer containing the pre-Symbol titanium silicide, 2.0 or more to 100 or less der Rue etching liquid. An etching method applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
The etching method is to apply an etching solution containing fluorine ions and an oxidizing agent to a substrate,
The etching method whose said oxidizing agent is a quinone type oxidizing agent represented by either of following formula (Q1)-(Q4) .

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4; An etching method applied to a substrate containing titanium and silicon and / or germanium to remove titanium,
The etching method is to apply an etching solution containing fluorine ions and an oxidizing agent to a substrate,
The oxidizing agent is a quinone-based oxidizing agent represented by any one of the following formulas (Q1) to (Q4) ,
The etching method, wherein the concentration of the fluorine ion is 0.1% by mass to 20% by mass, and the concentration of the oxidizing agent is 0.01% by mass to 2% by mass in the etching solution.

Each of R ^{Q1 to} R ^Q6 independently represents a substituent. m1 represents an integer of 0 to 4; m2 represents an integer of 0 to 2; m3 represents an integer of 0 to 4; m4 represents an integer of 0 to 4; m5 represents an integer of 0 to 4; m6 represents an integer of 0 to 4; Through the etching method according to claim 14 or 1 5, The method of producing a semiconductor substrate product for manufacturing a semiconductor substrate product.

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