Silicon oxide film etchant composition, etching method using same, and method for manufacturing semiconductor device

Abstract

The present invention relates to a silicon oxide film etching liquid composition comprising hydrogen fluoride (HF), ammonium fluoride (NH4F), (C4-C20) alkylamine, an amine-based oligomeric compound, and an organic acid, the composition being capable of selectively etching a silicon oxide film while minimizing damage to metal and insulating films such as a silicon nitride film and a silicon oxyfluoride film.

Description

Technical Field

[0001] This invention relates to a silicon oxide film etching solution composition with excellent etching selectivity relative to silicon oxide film (SiO2), as well as etching methods using the same and methods for fabricating semiconductor devices. Background Technology

[0002] In the manufacturing process of semiconductors or thin-film displays, insulating films such as silicon oxide films or silicon nitride films are used during circuit design to provide electrical isolation between metal wirings. Depending on the requirements, these insulating films are etched into specific shapes using an etchant that selectively etches only specific materials.

[0003] Existing etchants (buffered oxide etchants, BOE) used for etching silicon oxide films include hydrogen fluoride (HF) and ammonium fluoride (NH4F). While effective at etching silicon oxide films, they can also damage silicon nitride films and metal wiring. Furthermore, with the recent use of SiOF, known for its excellent insulating properties, as an insulating film material, there is a need to develop a new etchant that can protect SiOF and selectively etch silicon oxide films (SiO2) and their residues.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Korean Patent Publication No. 10-2010-0019328 (February 18, 2010) Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The purpose of this invention is to provide an etching solution composition and an etching method and a method for preparing semiconductor devices using the same, wherein the composition has a very low etching rate for insulating film materials and metal films other than silicon oxide film (SiO2), and can selectively etch silicon oxide film (SiO2).

[0009] Specifically, a silicon oxide film etching solution composition is provided, along with an etching method for the silicon oxide film using the same and a method for fabricating semiconductor devices. Compared to silicon nitride films, silicon oxyfluoride films (SiOF), and tungsten (W), the composition has an excellent etching selectivity for silicon oxide films (SiO2).

[0010] means for solving problems

[0011] One aspect of the present invention provides a silicon oxide film etching solution composition, the composition comprising hydrogen fluoride (HF), ammonium fluoride (NH4F), (C4-C20) alkylamine, amine oligomer and organic acid.

[0012] The amine oligomer can be a polyalkyleneimine with a number average molecular weight of 200 g / mol to 1000 g / mol.

[0013] The organic acid may be an (C4-C20) aliphatic compound containing a carboxyl group (-COOH) or a sulfonic acid group (-SO3H).

[0014] The (C4-C20) alkylamine may be octylamine.

[0015] The organic acid may be heptanoic acid.

[0016] According to one aspect, the silicon oxide film etching solution composition may contain 0.01% to 5% ammonium fluoride relative to the total weight of the composition.

[0017] According to one aspect, the silicon oxide film etching solution composition may contain 50 to 150 parts by weight of hydrogen fluoride relative to 100 parts by weight of ammonium fluoride.

[0018] According to one aspect, the silicon oxide film etching solution composition may contain 30 to 100 parts by weight of (C4-C20) alkylamine, 50 to 200 parts by weight of amine oligomer compound, and 20 to 150 parts by weight of organic acid, relative to 100 parts by weight of ammonium fluoride.

[0019] The silicon oxide film etching solution composition may also contain a balance of water.

[0020] According to one aspect of the silicon oxide film composition, the etch selectivity of the silicon oxide film (SiO2) relative to the silicon nitride film can be 2.5 or higher, and the etch selectivity of the silicon oxide film (SiO2) relative to the silicon fluoride oxyfluoride film (SiOF) can be (E... SiO2 / E SiOF The etch selectivity (E) can be above 3.0, relative to the etch selectivity (E) of the silicon oxide film (SiO2) over the tungsten (W) film. SiO2 / E W () can be 10 or more.

[0021] Another aspect of the present invention provides an etching method in which the silicon oxide film etching solution composition is used to selectively etch a silicon oxide film.

[0022] Another aspect of the present invention provides a method for fabricating a semiconductor device, the method comprising an etching process using the silicon oxide film etching solution composition.

[0023] Invention Effects

[0024] The silicon oxide film etching solution composition of the present invention exhibits a very low etching rate for insulating film materials such as silicon nitride films and silicon oxyfluoride films (SiOF), as well as metal films, and selectively etches only silicon oxide films (SiO2). Therefore, when using the silicon etching composition of the present invention, the silicon oxide film is selectively etched without damaging the insulating layer other than the silicon oxide film or the adjacent metal components. Detailed Implementation

[0025] Unless otherwise defined in this specification, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of effectively describing specific examples only and is not intended to limit the invention.

[0026] Unless otherwise indicated by the context, singular expressions used in this specification may also include plural expressions.

[0027] Furthermore, the numerical ranges used in this specification include lower limits, upper limits, and all values ​​within their ranges; logically derived increments within the defined range's form and width; all double-qualified values; and all possible combinations of upper and lower limits within numerical ranges qualified in different forms. Unless otherwise specified in this specification, values ​​outside the defined numerical range that may occur due to experimental errors or rounding are also included within the defined numerical ranges.

[0028] The term "comprising" in this specification is an open-ended description and has the same meaning as expressions such as "contains," "has," "has," or "characterizes," and does not exclude elements, materials, or processes not additionally listed.

[0029] The term "etch selectivity" in this specification refers to the ratio of the etching rate of a silicon nitride film, silicon oxyfluoride film (SiOF), or tungsten (W) film to the etching rate of a silicon oxide film (E). SiO2 The ratio of the etching selectivity ratio to the silicon oxide film is considered, and the higher the value of the etching selectivity ratio, the more selectively the silicon oxide film can be etched.

[0030] One aspect of the present invention provides an etching solution composition that exhibits very low etching rates for insulating film materials and metal films other than silicon oxide (SiO2), and selectively etches only silicon oxide (SiO2). Specifically, in the silicon oxide film etching solution composition according to one aspect, an excellent etching selectivity for silicon oxide (SiO2) can be achieved compared to silicon nitride films, silicon oxyfluoride films (SiOF), and tungsten (W).

[0031] The silicon nitride film refers to a silicon nitride film containing a SiN film and impurities (such as carbide or boron), for example, films containing SiCN, SiBN and SiCBN.

[0032] Specifically, the silicon oxide film etching solution composition may include hydrogen fluoride (HF), ammonium fluoride (NH4F), (C4-C20) alkylamine, amine oligomers and organic acids.

[0033] According to one aspect, the silicon oxide film etching solution composition having the composition combination described above overcomes the limitations of existing silicon oxide film etching solutions (buffered oxide etchant (BOE)). Specifically, it effectively etches only the silicon oxide film while minimizing damage to both the silicon nitride film and the metal film. Furthermore, it not only exhibits superior etching selectivity compared to silicon oxide films (SiO2) from SiOF, which has recently been used as an insulating film material, but also selectively removes silicon oxide residue.

[0034] For example, the amine oligomer may include repeating units represented by the following chemical formula 1, or repeating units represented by the following chemical formula 2, or combinations thereof.

[0035] [Chemical Formula 1]

[0036]

[0037] [Chemical Formula 2]

[0038]

[0039] (in the chemical formulas 1 and 2,

[0040] R 1 It is hydrogen, (C1-C7)alkyl, or amino(C1-C7)alkyl;

[0041] L 1 It is a single bond or a (C1-C7) alkylene group;

[0042] n and m are each an independent integer from 1 to 7.

[0043] As an example, the R 1 It can be hydrogen, (C1-C4)alkyl or amino(C1-C4)alkyl.

[0044] As an example, R1 can be an aminoalkyl group selected from hydrogen, or *-CH2-NH2, *-(CH2)2-NH2, *-(CH2)3-NH2 and *-(CH2)4-NH2.

[0045] As an example, the L 1 It can be (C1-C4) alkylene, or it can be ethylene or propylene.

[0046] As an example, n and m can each be an integer from 1 to 4, or an integer from 1 to 3, independently.

[0047] Specifically, the amine oligomer may include repeating units represented by the following chemical formula 1-1, repeating units represented by the following chemical formula 2-1, or combinations thereof.

[0048] [Chemical Formula 1-1]

[0049]

[0050] [Chemical Formula 2-1]

[0051]

[0052] As an example, the amine oligomer may be an oligomer containing repeating polyalkylimide units, repeating polyacrylamide units, or combinations thereof.

[0053] The polyalkylene imine repeating unit may refer to a unit containing alkylene and -(NR) 1 The repeating unit of )-, and the R 1 It can be hydrogen, (C1-C7)alkyl or (C1-C7)aminoalkyl.

[0054] As an example, the amine oligomer may be an oligomer containing repeating polyethyleneimine units, repeating polyacrylamide units, or combinations thereof.

[0055] As an example, the amine oligomer may be polyethyleneimine or polyacrylamide.

[0056] Specifically, the amine oligomer can be a polyalkylimide with a number average molecular weight of 100 g / mol to 1000 g / mol, more specifically, the number average molecular weight can be 200 g / mol to 1000 g / mol or 200 g / mol to 800 g / mol.

[0057] The organic acid may be an aliphatic acid containing a carboxyl group (-COOH) or a sulfonic acid group (-SO3H), specifically, it may be an aliphatic compound (C4-C20) having a carboxyl group or a sulfonic acid group. Non-limiting examples of the organic acid may be hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, decanoic acid, dodecanoic acid, nonanoic acid, or undecanoic acid, and more specifically, heptanoic acid may be used.

[0058] The (C4-C20) alkylamine can refer to a compound represented by R-NH2 (R is a C4-C20 alkyl), where R can be a straight-chain (C4-C20) alkyl or a straight-chain (C4-C12) alkyl.

[0059] The (C4-C20) alkylamine can be a linear (C4-C20) alkylamine, specifically a linear (C4-C12) alkylamine. As an example, it can be hexylamine, octylamine, decylamine, or dodecylamine, specifically octylamine, but it is not necessarily limited to these.

[0060] According to one aspect, relative to the total weight of the silicon oxide film etching solution composition, it may contain 0.01 wt% to 5 wt% ammonium fluoride, specifically, it may contain 0.01 wt% to 3 wt%, more specifically, it may contain 0.01 wt% to 0.1 wt%.

[0061] In addition, relative to 100 parts by weight of the ammonium fluoride, it may contain 50 to 150 parts by weight of hydrogen fluoride, specifically, 50 to 100 parts by weight, and more specifically, 60 to 100 parts by weight.

[0062] In addition, relative to 100 parts by weight of the ammonium fluoride, it may contain 30 to 100 parts by weight of (C4-C20) alkylamine, 50 to 200 parts by weight of amine oligomer, and 20 to 150 parts by weight of organic acid. Specifically, it may contain 30 to 80 parts by weight of (C4-C20) alkylamine, 50 to 150 parts by weight of amine oligomer, and 20 to 120 parts by weight of organic acid, and may also contain the balance of water.

[0063] When the above range is met, damage to the insulating film and metal film other than the silicon oxide film can be minimized while the etching rate of the silicon oxide film can be further improved.

[0064] Specifically, the etching rate of the silicon oxide film (SiO2) by the silicon oxide film etching solution composition according to one aspect can be... / minute or more, or / minute or more, or / minute or more, or / minute or more, specifically, can be / minutes to / minute, or / minutes to / minute, or / minutes to / minute. Additionally, the etching rate of the silicon oxide film etching solution composition for the residue on the silicon oxide film can be... / minute or more, or / minute or more, or / minute or more, or / minute or more, specifically, can be / minutes to / minute, or / minutes to / minute, or / minutes to / minute.

[0065] Meanwhile, according to one aspect of the silicon oxide film etching solution composition, the etching selectivity ratio of the silicon oxide film (SiO2) relative to the silicon nitride film can be 2.5 or higher. The silicon nitride film refers to a silicon nitride film containing a SiN film and impurities (such as carbide or boron), for example, films containing SiCN, SiBN, and SiCBN.

[0066] As an example, according to one aspect of the silicon oxide film etching solution composition, the etching selectivity (E) of the silicon oxide film (SiO2) relative to the SiN film is... SiO2 / E SiN The value can be 2.5 or higher, specifically 2.5 to 10, or 3 to 8, but it is not necessarily limited to these values.

[0067] Furthermore, according to one aspect of the silicon oxide film etching solution composition, the etching selectivity (E) of the silicon oxide film (SiO2) relative to the SiCN film is... SiO2 / E SiCN The value can be 5 or more, or 7 or more, or 10 or more. Specifically, it can be 5 to 20 or 10 to 20, but it is not necessarily limited to these values.

[0068] Furthermore, according to one aspect of the silicon oxide film etching solution composition, the etching selectivity (E) of the silicon oxide film (SiO2) relative to the SiBN film is... SiO2 / E SiBN The value can be 3 or more, or 5 or more, or 7 or more. Specifically, it can be 3 to 20 or 5 to 15, but it is not necessarily limited to these values.

[0069] Furthermore, according to one aspect of the silicon oxide film etching solution composition, the etching selectivity (E) of the silicon oxide film (SiO2) relative to the fluorinated silicon oxide film (SiOF) is...SiO2 / E SiOF The value can be 3 or more, or 3.5 or more, or 5 or more. Specifically, it can be 3 to 10, or 3.5 to 10, but it is not necessarily limited to these values.

[0070] Furthermore, according to one aspect of the silicon oxide film etching solution composition, the etching selectivity (E) of the silicon oxide film (SiO2) relative to the tungsten metal film (W) is... SiO2 / E W The value can be 10 or more, or 12 or more, or 15 or more, or 20 or more. Specifically, it can be 10 to 30, or 12 to 30, or 15 to 30, but it is not necessarily limited to these values.

[0071] The etching method using a silicon oxide film etching solution composition according to one aspect will be described in detail below.

[0072] According to one aspect, the etching method can be a method that can selectively etch silicon oxide films compared to silicon nitride films, silicon oxyfluoride films (SiOF) films, or tungsten (W) films.

[0073] In addition, one aspect provides a method for fabricating a semiconductor device, the method comprising an etching process for selectively etching a silicon oxide film using the silicon oxide film etching solution composition.

[0074] The silicon oxide film is not limited to any silicon oxide film commonly used in this technical field. For example, it can be selected from spin-on-dielectric (SOD) films, high-density plasma (HDP) films, thermal oxide films, borophosphate silicon glass (BPSG) films, phospho silicon glass (PSG) films, boro silicon glass (BSG) films, polysilazane (PSZ) films, fluorosilicone glass (FSG) films, low-pressure tetraethyl orthosilicate (LP-TEOS) films, plasma-enhanced tetraethyl orthosilicate (PETEOS) films, high-temperature oxide (HTO) films, and medium-temperature oxide (Medium-temperature oxide) films. A film comprising at least one of the following: Temperature Oxide (MTO) film, Undopped Silicate Glass (USG) film, Spin On Glass (SOG) film, Advanced Planarization Layer (APL) film, Atomic Layer Deposition (ALD) film, Plasma Enhanced Oxide (PE) film, and O3-Tetra Ethyl Ortho Silicate (O3-TEOS) film.

[0075] Furthermore, the method for selectively etching a silicon oxide film using the aforementioned silicon oxide film etching solution composition can be performed according to processing methods commonly used in this technical field. As a non-limiting example, the etching target (semiconductor substrate) can be immersed in a solution of the silicon oxide film etching solution composition according to one aspect, or the etching can be performed by a spraying method, etc.

[0076] As an example, the etching method can be carried out at a process temperature below 50°C, specifically, at a process temperature between 20°C and 50°C, and more specifically, at a process temperature of 25°C.

[0077] In the etching method, when silicon oxide film, silicon nitride film, silicon oxyfluoride film, tungsten film and photoresist film formed on the substrate are mixed, the silicon oxide film can be selectively and rapidly etched, and the formation of precipitates can be suppressed.

[0078] The substrate can be made of various materials, such as silicon, quartz, glass, silicon wafers, polymers, metals, and metal oxides, but is not limited thereto. As an example of the polymer substrate, thin film substrates such as polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate, and cycloolefin polymers can be used, but are not limited thereto.

[0079] The silicon oxide film, silicon nitride film, silicon fluoride oxyfluoride film, and tungsten film may each be a single-layer film, and may be formed from a double-layer film or a multi-layer film (multilayer film), and in the case of a double-layer film or a multilayer film, their stacking order is not limited.

[0080] In addition, the method for fabricating semiconductor devices, including an etching process that selectively etches a silicon oxide film (using the aforementioned silicon oxide film etching solution composition), can also be carried out in accordance with methods commonly used in this technical field.

[0081] According to the semiconductor device fabrication method described above, in semiconductor devices where insulating films such as silicon oxide films and silicon nitride films are alternately stacked or mixed, selective etching of the silicon oxide film is possible, and damage to insulating films such as silicon nitride films and metal wiring is effectively suppressed, thereby greatly improving the stability, efficiency, and reliability of the semiconductor device fabrication process. In this invention, there are no particular limitations on the type of semiconductor device.

[0082] Therefore, the etching method of the present invention can be effectively applied to processes that require selective etching of silicon oxide films.

[0083] The above implementation examples will be described in more detail below through embodiments. However, the following embodiments are for illustrative purposes only and do not limit the scope of the invention.

[0084] [Examples 1 to 4 and Comparative Examples 1 to 7]

[0085] The silicon oxide film etching solution composition was prepared by mixing the components (wt%) listed in Table 1 below with water and stirring at 500 rpm for 5 minutes at room temperature. The remaining water was mixed to bring the total weight to 100% by weight.

[0086] Table 1

[0087]

[0088] <Evaluation Example>

[0089] Evaluation 1. Etching rate and etch selectivity

[0090] Each silicon wafer deposited with SiN film, SiCN film, SiBN film, SiOF film, tungsten (W) film and SiO2 film was cut into 20mm×30mm pieces to be used as test pieces.

[0091] 100g of the etching solution composition prepared in the examples and comparative examples was placed in a double-jacketed beaker container. The temperature was then adjusted to 25°C using a constant-temperature circulating bath, and the prepared evaluation specimens were etched for a specified time. During the additional etching process, a magnetic stirrer was used to stir at approximately 300 rpm. After rinsing the etched specimens with ultrapure water for approximately 30 seconds, the solution was then subjected to etching at 3.0 kgf / cm³. 2 Nitrogen drying was performed under pressure conditions. The etching rate of the sample was shown in Equation 1 below, and was converted to an etching rate per minute by comparing the thicknesses before and after etching. The thickness was measured using a non-contact thin film thickness measuring device (Spectroscopic Ellipsometer M-2000).

[0092] In Table 2 below, the SiO2 selectivity refers to the ratio of the etching rate for each etched object to the etching rate for the silicon oxide film (SiO2).

[0093] [Mathematical Expression 1]

[0094]

[0095] Evaluation 2. Removal performance of silica residue

[0096] Patterned substrates with silicon oxide residue were cut into 20mm x 30mm pieces for use as test pieces.

[0097] 100g of the etching solution composition prepared in the examples and comparative examples was placed in a double-jacketed beaker container. The temperature was then adjusted to 25°C using a constant-temperature circulating bath, and the prepared evaluation specimens were etched for a specified time. During the additional etching process, a magnetic stirrer was used to stir at approximately 300 rpm. The etched specimens were rinsed with ultrapure water for approximately 10 seconds, followed by rinsing with IPA for 10 seconds, and then subjected to a solution at 3.0 kgf / cm³. 2 Nitrogen drying is performed under pressure conditions.

[0098] Silica residue levels were compared before and after evaluation using a scanning electron microscope (SEM, manufactured by Hitachi, Japan). Based on the SiO2 residue removal level, the measurement results were labeled as O (excellent removal performance), △ (moderate removal performance), and X (poor removal performance).

[0099] Table 2

[0100]

[0101]

[0102] As can be seen from Table 2, compared with SiN film, SiCN film, SiBN film, SiOF film and tungsten (W) film, the silicon oxide film etching solution composition of the present invention achieves a very excellent etching selectivity for silicon oxide film (SiO2).

[0103] As described above, this invention has been illustrated by specific details and limited embodiments, but these are provided only to help to more fully understand the invention. The invention is not limited to the above embodiments, and those skilled in the art to which this invention pertains can make various modifications and variations from these descriptions.

[0104] Therefore, the concept of the present invention should not be limited to the described embodiments, and not only to the claims described below, but also to all that are equivalent to or have equivalent variations of the claims.

Claims

1. A silicon oxide film etching liquid composition, wherein, hydrogen fluoride, ammonium fluoride, a C4-C20 alkyl amine, an amine-based oligomeric compound, and an organic acid are contained.

2. The silicon oxide film etching liquid composition according to claim 1, wherein, the amine-based oligomeric compound is a polyalkylene imine having a number average molecular weight of 200 g / mol to 1000 g / mol.

3. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, the organic acid is a C4-C20 aliphatic compound containing a carboxyl group or a sulfonic acid group.

4. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, the C4-C20 alkyl amine is octyl amine.

5. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, the organic acid is heptanoic acid.

6. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, 0.01 to 5% by weight of ammonium fluoride is contained with respect to the total weight of the silicon oxide film etching liquid composition.

7. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, 50 to 150 parts by weight of hydrogen fluoride is contained with respect to 100 parts by weight of ammonium fluoride.

8. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, 30 to 100 parts by weight of the C4-C20 alkyl amine, 50 to 200 parts by weight of the amine-based oligomeric compound, and 20 to 150 parts by weight of the organic acid are contained with respect to 100 parts by weight of ammonium fluoride.

9. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, a balance of water is further contained.

10. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, the etching selectivity ratio with respect to a silicon nitride film is 2.5 or more.

11. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, Etch selectivity ratio E of the silicon oxide film with respect to the silicon oxyfluoride film SiO2 / E SiOF is 3.0 or more.

12. The silicon oxide film etching liquid composition according to claim 1 or 2, wherein, Etch selectivity ratio E of the silicon oxide film with respect to the metal tungsten film SiO2 / E W is 10 or more.

13. An etching method, wherein, a silicon oxide film is selectively etched using the silicon oxide film etching liquid composition selected from claim 1 or 2.

14. A method for producing a semiconductor device, wherein, an etching process using the silicon oxide film etching liquid composition selected from claim 1 or 2 is included.

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