Composition for etching silicon nitride layer

Abstract

The composition for etching silicon nitride layers described in this invention includes hydrofluoric acid, a boron-containing compound or a phosphite compound, water, and a proton solvent. This composition for etching silicon nitride layers can etch the silicon nitride layer at high speed while etching less of the silicon oxide layer.

Description

Technical Field

[0001] The present disclosure relates to a composition for etching a silicon nitride layer. Prior Art

[0002] Silicon nitride layers are typically used as insulating layers in semiconductor manufacturing processes. Silicon nitride layers can be used alone or in a stacked fashion, alternating between one or more silicon oxide layers and one or more silicon nitride layers. Silicon oxide layers and silicon nitride layers can also be used as hard masks for forming conductive patterns (e.g., metal lines).

[0003] Phosphoric acid is typically used to etch silicon nitride layers. However, increasing the temperature of the phosphoric acid to increase the etching rate increases both the etching rate of the silicon oxide layer and the etching rate of the silicon nitride layer, resulting in a decrease in selectivity.

[0004] To increase the etching selectivity of the silicon nitride layer, a method has been proposed to control the etching rate of the silicon oxide layer by using phosphoric acid and a silane compound in an etching composition. However, silane compounds form silanol groups, which may cause the surrounding alkoxysilane compounds to aggregate and cause gelation of the composition.

[0005] Furthermore, when performing an etching process at a high temperature, the etching composition may boil, causing components in the etching composition to evaporate. This can lead to problems such as changes in the composition of the etching composition during the etching process, causing aggregation of the composition or a decrease in the etching rate, and thus reducing the selectivity of the silicon nitride layer.

[0006] Therefore, it is necessary to develop an etching composition that does not cause agglomeration of the etching composition, allows the etching process to be performed at a relatively low temperature, and does not cause changes in the composition of the etching composition during the etching process, thereby providing a higher etching selectivity ratio for the silicon nitride layer. Summary of the Invention

[0007] One of the objectives of the present invention is to provide a composition for etching a silicon nitride layer that can achieve a high etching rate. To achieve the above objectives, the present invention adopts the following technical solutions:

[0008] 1. A composition for etching a silicon nitride layer, comprising: hydrofluoric acid, a boron-containing compound or a phosphite compound, water, and a protic solvent.

[0009] 2. The composition for etching a silicon nitride layer as described in 1 above, wherein the phosphite compound is represented by the following chemical formula 1: [Chemical Formula 1] (In Chemical Formula 1, R1 to R3 may each independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkylaryl group having 7 to 20 carbon atoms).

[0010] 3. The composition for etching a silicon nitride layer as described in 2 above, wherein in Chemical Formula 1, R1 to R3 may each independently be hydrogen or an alkyl group having 1 to 4 carbon atoms.

[0011] 4. The composition for etching a silicon nitride layer as described in 2 above, wherein in Chemical Formula 1, R1 to R3 are the same as each other.

[0012] 5. The composition for etching a silicon nitride layer as described in 1 above, wherein the content of the phosphite compound is between 0.1% by weight and 10% by weight of the total weight of the composition.

[0013] 6. The composition for etching a silicon nitride layer as described in 1 above, wherein the content of the phosphite compound is between 0.5 weight percent and 5 weight percent of the total weight of the composition.

[0014] 8. The composition for etching a silicon nitride layer as described in 1 above, wherein the boron-containing compound comprises a borate compound.

[0015] The composition for etching a silicon nitride layer as described in 1 above, wherein the boron-containing compound is represented by the following chemical formula 2: [Chemical Formula 2] (In Chemical Formula 2, R1 to R3 may each independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms).

[0016] 9. The composition for etching a silicon nitride layer as described in 8 above, wherein in Chemical Formula 2, R1 to R3 can each independently be hydrogen or an alkyl group having 1 to 4 carbon atoms.

[0017] 10. The composition for etching a silicon nitride layer as described in 8 above, wherein in Chemical Formula 2, R1 to R3 are the same as each other.

[0018] 11. The composition for etching a silicon nitride layer as described in 1 above, wherein the content of the boron-containing compound is between 0.01 weight percent and 5 weight percent of the total weight of the composition.

[0019] 12. The composition for etching a silicon nitride layer as described in 1 above, wherein the content of the boron-containing compound is between 0.1 weight percent and 3 weight percent of the total weight of the composition.

[0020] 13. The composition for etching a silicon nitride layer as described in 1 above, wherein the conductivity of the protic solvent is equal to or less than 10 μS / cm, and the conductivity is measured in a solution containing 1 weight percent hydrofluoric acid dissolved in the protic solvent.

[0021] 14. The composition for etching a silicon nitride layer as described in 1 above, wherein the boiling point of the protic solvent is equal to or greater than 80°C.

[0022] 15. The composition for etching a silicon nitride layer as described in 1 above, wherein the protic solvent comprises an alcohol solvent.

[0023] 16. The composition for etching a silicon nitride layer as described in 1 above, wherein the content of hydrofluoric acid is between 0.1 weight percent and 10 weight percent of the total weight of the composition.

[0024] 17. The composition for etching a silicon nitride layer as described in 1 above, wherein the water content is between 0.5 weight percent and 10 weight percent of the total weight of the composition.

[0025] 18. The composition for etching a silicon nitride layer as described in 1 above, wherein the ratio of the content of hydrofluoric acid to the content of water in the total weight of the composition is between 0.1 and 1.5.

[0026] 19. The composition for etching a silicon nitride layer as described in 1 above, wherein the composition does not contain a silicon compound.

[0027] 20. The composition for etching a silicon nitride layer as described in 1 above, wherein the composition does not contain a basic compound.

[0028] According to an exemplary embodiment of the present invention, a composition for etching a silicon nitride layer can be used to etch a silicon nitride layer at a high speed.

[0029] In addition, the composition for etching the silicon nitride layer may include a boron-containing compound or a phosphite compound to selectively etch the silicon nitride layer. Therefore, the composition for etching the silicon nitride layer can relatively etch more of the silicon nitride layer and etch less of the silicon oxide layer. Simple diagram description

[0030] none Implementation Method

[0031] According to an exemplary embodiment of the present disclosure, a composition for etching a silicon nitride layer is provided, which comprises hydrofluoric acid, a boron-containing compound or a phosphite compound, water, and a protic solvent.

[0032] The present invention is described in detail below with reference to a number of embodiments. However, these embodiments are merely illustrative, and the scope of the present disclosure is not limited to the specific embodiments described.

[0033] Hydrofluoric acid (HF) can be used as a weak acid compound in etching species. In compositions used to etch silicon nitride layers (hereinafter referred to as "compositions"), hydrofluoric acid can serve as an etching species in the form of HF or in the form of HF 2- ions. Unlike hydrofluoric acid, fluorine-containing compounds can only serve as etching species when they are hydrated to form ions or through other reactions to form HF. However, because hydrofluoric acid itself forms HF 2- or is easily ionized, it is suitable as an etching species in compositions.

[0034] HF 2- ions formed by the ionization of hydrofluoric acid can etch silicon oxide layers, while hydrofluoric acid (HF) can etch silicon nitride layers. Since hydrofluoric acid can be ionized into HF 2- ions in an aqueous solvent, etching of the silicon nitride layer can be relatively minimal when the composition contains an aqueous solvent. Therefore, to suppress the formation of HF 2- ions, the composition preferably contains the following protic solvent as the primary solvent.

[0035] For example, fluorine-containing compounds with small molecular weights and different from hydrofluoric acid (e.g., lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), and ammonium fluoride (NH4F)) are insoluble in organic solvents due to the strong bond between the cation and the fluoride ion (F-). Furthermore, fluorine-containing compounds with larger molecular weights and different from hydrofluoric acid (e.g., tetraalkylammonium fluoride) are soluble in organic solvents, but they also have the problem that their large molecular weight makes it difficult for the fluorine-containing etching reactants to react with the silicon nitride layer due to steric hindrance, thus failing to exhibit the desired etching performance.

[0036] Based on the total weight of the composition, the content of hydrofluoric acid may be between 0.1 weight percent (wt%) and 10 weight percent of the total weight of the composition. In some embodiments, the content may be between 0.5 weight percent and 5 weight percent of the total weight of the composition, or between 1 weight percent and 3 weight percent of the total weight of the composition.

[0037] Within the above range, the composition can etch more of the silicon nitride layer than the silicon oxide layer, while also having an appropriate etching rate relative to the silicon nitride layer.

[0038] Traditionally, phosphate compounds (e.g., phosphoric acid) have been used as silicon etching reactants in etching compositions. However, phosphate compounds contain one oxygen atom double-bonded to a phosphorus atom and three oxygen atoms single-bonded to the phosphorus atom, resulting in the phosphorus atom lacking any unshared electron pairs. Therefore, phosphate compounds pose a problem not only in oxidizing silicon but also in oxidizing silicon oxide and / or silicon nitride layers. Phosphite compounds, on the other hand, contain three oxygen atoms single-bonded to phosphorus atoms. Therefore, the phosphorus atom possesses unshared electron pairs. These unshared electron pairs can form nucleophilic bonds with silicon atoms, preventing contact between the silicon atom and the etching species. Consequently, etching of silicon oxide and silicon nitride layers can be prevented. Because the silicon atoms in the silicon oxide layer have lost more electrons to the oxygen atoms with higher electronegativity, their unshared electron pairs with the phosphorus atoms are more likely to undergo nucleophilic reactions. Therefore, the phosphite compound can enhance the corrosion resistance of the silicon oxide layer in the etching composition and provide a higher silicon etching selectivity.

[0039] Although the phosphite compound reduces the etching rate of the composition for both the silicon nitride layer and the silicon oxide layer, the reduction in the etching rate of the silicon oxide layer is greater than the reduction in the etching rate of the silicon nitride layer. Therefore, the etching rate of the silicon nitride layer is still increased relative to the etching rate of the silicon nitride layer. Therefore, the composition can have a high etching selectivity.

[0040] The phosphite compound can be represented by the following chemical formula 1: [Chemical Formula 1] In Chemical Formula 1, R1 to R3 may each independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, an aromatic group having 6 to 10 carbon atoms, or an alkaryl group having 7 to 20 carbon atoms.

[0041] The aromatic group may be a hydrocarbon group including at least one aromatic ring, and may be, for example, a phenyl group, a naphthalene group, a fluorene group, or the like.

[0042] An alkaryl group is a hydrocarbon group having the following structure in which at least one hydrogen atom of an aromatic group is replaced by an alkyl group. Examples of alkaryl groups include alkylphenyl groups, alkylnaphthalene groups, and alkylfluorene groups. The alkyl group substituted by the aromatic group may be an alkyl group having 1 to 10 carbon atoms.

[0043] In some embodiments, at least one of R1 to R3 may be an alkyl group having 1 to 10 carbon atoms, an aromatic group having 6 to 10 carbon atoms, or an alkaryl group having 7 to 20 carbon atoms. For example, when R1 and R2 are hydrogen, R3 may not be hydrogen. Alternatively, when R1 is hydrogen, at least one of R2 and R3 may not be hydrogen. In this case, the phosphite compound may have high stability.

[0044] In some embodiments, R1 to R3 may be an alkyl group having 1 to 4 carbon atoms, and the alkyl group may have a linear shape. For example, R1 to R3 may each independently be a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, etc.

[0045] When R1 to R3 are alkyl groups having 1 to 4 carbon atoms, the phosphorus atoms are not covered by steric hindrance. As a result, the interaction between the unshared electron pairs of the phosphorus atoms and silicon atoms can be smooth, and the corrosion resistance of the silicon oxide layer relative to the composite can be enhanced.

[0046] R1 to R3 may be the same as each other. Therefore, the phosphite compound can have high structural stability and can further prevent etching of the silicon oxide layer.

[0047] Based on the total weight of the composition, the phosphite compound may be present in an amount ranging from 0.1 weight percent to 10 weight percent of the total weight of the composition. According to some embodiments, the phosphite compound may be present in an amount ranging from 1 weight percent to 6 weight percent of the total weight of the composition, or from 2 weight percent to 4 weight percent of the total weight of the composition.

[0048] Within the above range, the etching rate of the silicon nitride layer will not be significantly reduced, while the etching of the silicon oxide layer by the composition is also fully prevented.

[0049] The boron-containing compound reduces the composition's etching rate for both the silicon nitride layer and the silicon oxide layer. However, because the reduction in the silicon oxide layer's etching rate is greater than the reduction in the silicon nitride layer's etching rate, the composition's etching rate for the silicon nitride layer is still increased relative to the etching rate for the silicon oxide layer. Consequently, the composition can exhibit a high etching selectivity.

[0050] For example, the boron-containing compound can be an ionic compound or a non-ionic compound. For example, the boron-containing compound can include a metal cation and a borohydride anion. In addition, the non-ionic compound can include a borate compound.

[0051] The boron-containing compound can be represented by the following chemical formula 2: [Chemical Formula 2] In Chemical Formula 2, R1 to R3 may each independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms.

[0052] For example, when R1 to R3 are hydrogen, the boron-containing compound may be boric acid.

[0053] The aromatic group is a hydrocarbon group containing at least one aromatic ring, and may be, for example, a phenyl group, a naphthyl group, a fluorenyl group, or the like.

[0054] In some embodiments, R1 to R3 may be an alkyl group having 1 to 4 carbon atoms, and the alkyl group may have a straight chain shape. For example, R1 to R3 may each independently be a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, etc.

[0055] When the alkyl group is an alkyl group having 1 to 4 carbon atoms, the boron atom may not be covered by steric hindrance. Therefore, the interaction between the boron atom and the silicon atom may be smooth, and the corrosion protection effect of the silicon oxide layer relative to the composition may be improved.

[0056] R1 to R3 may be the same as each other. Therefore, the boron-containing compound can have high structural stability and can further prevent etching of the silicon oxide layer.

[0057] Based on the total weight of the composition, the boron-containing compound may be present in an amount ranging from 0.01 weight percent to 5 weight percent of the total weight of the composition. According to some embodiments, the boron-containing compound may be present in an amount ranging from 0.1 weight percent to 3 weight percent of the total weight of the composition.

[0058] Within the above range, the etching rate of the silicon nitride layer will not be significantly reduced, while the etching of the silicon oxide layer by the composition is also fully prevented.

[0059] Protic solvents can reduce the ionization of hydrofluoric acid, thereby suppressing the generation of HF 2- ions used to etch the silicon oxide layer.

[0060] Furthermore, etching the silicon nitride layer requires a step to activate the layer, and proton solvents can improve the stability of this activation step. Therefore, etching can be performed smoothly while maintaining the activation state of the silicon nitride layer.

[0061] The protic solvent may have a conductivity of 10 μS / cm or less. In some embodiments, the protic solvent may have a conductivity of 5 μS / cm or less, or 2 μS / cm or less.

[0062] The conductivity can be measured by dissolving 1 weight percent hydrofluoric acid in a solution containing a protic solvent. The solution may contain 99 weight percent protic solvent and 1 weight percent hydrofluoric acid.

[0063] Conductivity can be measured after calibration using a standard solution. For example, the standard solution can be Mettler Toledo Standard Solution (1413 μS / cm).

[0064] The electrical conductivity can be measured using, for example, a conductivity meter (Mettler Toledo, DLS-0005), and can be measured at room temperature (eg, 25° C.).

[0065] When the electrical conductivity of the protic solvent is within the above range, the ionization of hydrofluoric acid can be reduced, thereby suppressing the formation of HF 2- ions used to etch the silicon oxide layer.

[0066] The protic solvent may have a boiling point of 80° C. or higher. Therefore, the volatilization amount of the protic solvent during the etching process can be very small, and the problem of reduced stability of the etching process due to large changes in the composition ratio during the process can be prevented.

[0067] The boiling point of the protic solvent may be selected in consideration of the ambient temperature in which the etching process is performed. For example, the boiling point of the protic solvent may be 30° C. or higher than the ambient temperature in which the etching process is performed.

[0068] The protic solvent may include an alcohol solvent. The alcohol solvent may meet the above-mentioned conductivity and boiling point ranges while also having high polarity. In some embodiments, the alcohol solvent may be an alcohol solvent having 3 or more carbon atoms and may be a polyol.

[0069] Protic solvents can be glycols, such as ethylene glycol, propylene glycol, butyl glycol, glycerol, propylene glycol monomethyl ether, propanol, butanol, hexanol, and 2-methylhydroxyisobutyrate. These protic solvents can be used alone or in combination of two or more.

[0070] The content of the protic solvent can be used to balance the content of other components in the composition. Balance refers to the remaining amount used to control the content of other components based on 100% by weight of the composition.

[0071] For example, based on the total weight of the composition, the content of the protic solvent can be greater than 84 weight percent and less than 98.5 weight percent.

[0072] In order to dissolve the hydrofluoric acid in the composition, a small amount of water may be included to increase the etching rate of the silicon nitride layer of the composition.

[0073] Based on the total weight of the composition, the water content may range from 0.5 weight percent to 10 weight percent of the total weight of the composition. In some embodiments, the water content may range from 1 to 5 weight percent of the total weight of the composition. Within this range, the solubility of hydrofluoric acid can be increased to ensure an appropriate etching process rate while preventing excessive ionization of the hydrofluoric acid, thereby preventing etching of the silicon oxide layer.

[0074] According to an exemplary embodiment, the water may be ultrapure water.

[0075] According to an exemplary embodiment, hydrofluoric acid can be used to prepare the composition in the form of an aqueous solution.

[0076] According to an exemplary embodiment, the ratio of the content of hydrofluoric acid to the content of water in the total weight of the composition may be between 0.1 and 2. According to some embodiments, the ratio of the content of hydrofluoric acid to the content of water in the total weight of the composition may be between 0.2 and 2.

[0077] Within the above range, excessive ionization of hydrofluoric acid can be prevented, thereby further preventing etching of the silicon oxide layer, while increasing the solubility of hydrofluoric acid to ensure an appropriate etching process rate.

[0078] According to an exemplary embodiment, the composition may not further contain other acidic compounds. The acidic compound described herein is a compound other than hydrofluoric acid, a boron-containing compound, and a phosphite compound, and may include, for example, an inorganic acid (e.g., sulfuric acid, nitric acid, or hydrochloric acid) or an organic acid.

[0079] The composition may not contain other acidic compounds, so that the etching mechanism of the silicon nitride layer by hydrofluoric acid may not be interfered with by other side reactions.

[0080] According to an exemplary embodiment, the composition may not include a silicon compound. The silicon compound described herein may include a linear or cyclic organic compound containing at least one silicon atom.

[0081] According to an exemplary embodiment, the composition may not include a basic compound. The basic compound described herein may include an organic basic compound or an inorganic basic compound.

[0082] For example, the organic basic compound may include one of a quaternary alkyl ammonium salt compound, an azabicyclo compound, a diazabicyclo compound, and a triazabicyclo compound.

[0083] The alkyl quaternary ammonium salt compound may include at least one selected from the group consisting of ammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, benzyltriethylammonium hydroxide, diethyldimethylammonium hydroxide, and methyltributylammonium hydroxide.

[0084] The inorganic alkaline compound may include metal hydroxides, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide.

[0085] In addition to the above components, the composition may further include conventional additives, and the additives may include corrosion inhibitors, etc. In addition, the additives are not limited thereto, and various other additives known in the art may be optionally added.

[0086] According to an exemplary embodiment, in a semiconductor manufacturing process, the composition can be used to selectively wet etch a silicon nitride layer in a shallow trench isolation (STI) or gate electrode formation process of a DRAM or NAND flash memory.

[0087] The etching process can be performed by wet etching methods known in the art. For example, etching can be performed by dipping and / or spraying.

[0088] The etching process can be performed at a relatively low temperature. For example, the etching process can be performed at a temperature of approximately 20° C. to 100° C., or 50° C. to 80° C. Thus, an increase in the etching rate of the silicon oxide layer can be prevented.

[0089] During the etching process, the silicon nitride layer may have an etching rate of 1 angstrom / minute (Å / min) or greater. In some embodiments, the silicon nitride layer may have an etching rate of 2 Å / min or greater, or 3 Å / min or greater. In some embodiments, the silicon nitride layer may have an etching rate of 10 Å / min or less.

[0090] During the etching process, the etching rate of the silicon oxide layer can be less than 2 angstroms / minute. In some embodiments, the etching rate of the silicon oxide layer can be less than 1 angstrom / minute.

[0091] The ratio of the etching rate of the silicon nitride layer to the etching rate of the silicon oxide layer may be 2 or greater. In some embodiments, the ratio of the etching rate of the silicon nitride layer to the etching rate of the silicon oxide layer may be 3 or greater, or 6 or greater. In some embodiments, the ratio of the etching rate of the silicon nitride layer to the etching rate of the silicon oxide layer may be 20 or less.

[0092] Within the above range, the etching rate of the silicon nitride layer is greater than the etching rate of the silicon oxide layer, and therefore, a fine pattern can be formed by etching only the silicon nitride layer.

[0093] The following supplementary explanations of the embodiments of the present invention are provided with reference to specific experimental examples. It is important to note that the examples and comparative examples included in the experimental examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate and make various changes, modifications, and alterations within the scope and spirit of the present invention. Such changes, modifications, and alterations may also be appropriately included in the scope of the patent application appended hereto.

[0094] Compositions for etching silicon nitride layers prepared using a fluorine-containing compound, a phosphorus-containing compound, or a boron-containing compound, water, and an organic solvent are listed in Tables 1 and 2 below. The content of each component is expressed as a weight percentage based on the total weight of the composition.

[0095] Among them, Comparative Example A2 and Comparative Example B2 are the same as each other and are listed in Table 1 and Table 2 respectively for comparison. [Table 1] Fluorinated compounds Phosphorus-containing compounds organic solvents water type content type content type content content Experimental Example A1 A-1 0.3 P-2 3 C-2 95.7 1 Experimental Example A2 A-1 0.5 P-2 3 C-2 95.5 1 Experimental Example A3 A-1 1 P-2 3 C-2 95 1 Experimental Example A4 A-1 2 P-2 3 C-2 93 2 Experimental Example A5 A-1 3 P-2 3 C-2 91 3 Experimental Example A6 A-1 5 P-2 3 C-2 87 5 Experimental Example A7 A-1 7 P-2 3 C-2 83 7 Experimental Example A8 A-1 1 P-2 0.5 C-2 97.5 1 Experimental Example A9 A-1 1 P-2 1 C-2 97 1 Experimental Example A10 A-1 1 P-2 2 C-2 96 1 Experimental Example A11 A-1 1 P-2 4 C-2 94 1 Experimental Example A12 A-1 1 P-2 6 C-2 92 1 Experimental Example A13 A-1 1 P-2 8 C-2 90 1 Experimental Example A14 A-1 1 P-2 3 C-1 95 1 Experimental Example A15 A-1 1 P-2 3 C-3 95 1 Experimental Example A16 A-1 1 P-2 3 C-4 95 1 Experimental Example A17 A-1 1 P-3 3 C-5 95 1 Experimental Example A18 A-1 1 P-1 3 C-2 95 1 Experimental Example A19 A-1 1 P-3 3 C-2 95 1 Experimental Example A20 A-1 1 P-4 3 C-2 95 1 Experimental Example A21 A-1 1 P-5 3 C-2 95 1 Experimental Example A22 A-1 1 P-6 3 C-2 95 1 Experimental Example A23 A-1 1 P-2 3 C-2 95.5 0.5 Experimental Example A24 A-1 1 P-2 3 C-2 93 3 Experimental Example A25 A-1 1 P-2 3 C-2 91 5 Experimental Example A26 A-1 1 P-2 3 C-2 89 7 Experimental Example A27 A-1 1 P-7 3 C-2 95 1 Experimental Example A28 A-1 7 P-2 3 C-2 80 10 Comparative Example A1 - - P-2 3 C-2 96 1 Comparative Example A2 A-1 1 - - C-2 98 1 Comparative Example A3 A-1 1 P-2 3 - - 96 Comparative Example A4 A-2 1 P-2 3 - - 96 Comparative Example A5 A-3 1 P-2 3 - - 96 Comparative Example A6 A-2 1 P-2 3 C-2 95 1 Comparative Example A7 A-3 1 P-2 3 C-2 95 1 Comparative Example A8 A-4 1 P-2 3 C-2 95 1 Comparative Example A9 A-1 1 P-8 3 C-2 95 1 Comparative Example A10 A-1 1 P-3 3 C-6 95 1 Comparative Example A11 A-1 1 P-3 3 C-7 95 1

[0096] [Table 2] Fluorinated compounds Boron-containing compounds organic solvents water type content type content type content content Experimental Example B1 A-1 0.3 B-3 0.3 C-2 98.4 1 Experimental Example B2 A-1 0.5 B-3 0.3 C-2 98.2 1 Experimental Example B3 A-1 1 B-3 0.3 C-2 97.7 1 Experimental Example B4 A-1 2 B-3 0.3 C-2 95.7 2 Experimental Example B5 A-1 3 B-3 0.3 C-2 93.7 3 Experimental Example B6 A-1 5 B-3 0.3 C-2 89.7 5 Experimental Example B7 A-1 7 B-3 0.3 C-2 85.7 7 Experimental Example B8 A-1 1 B-3 0.05 C-2 97.95 1 Experimental Example B9 A-1 1 B-3 0.1 C-2 97.9 1 Experimental Example B10 A-1 1 B-3 1 C-2 97 1 Experimental Example B11 A-1 1 B-3 3 C-2 95 1 Experimental Example B12 A-1 1 B-3 5 C-2 93 1 Experimental Example B13 A-1 1 B-3 0.3 C-1 97.7 1 Experimental Example B14 A-1 1 B-3 0.3 C-3 97.7 1 Experimental Example B15 A-1 1 B-3 0.3 C-4 97.7 1 Experimental Example B16 A-1 1 B-1 0.3 C-2 97.7 1 Experimental Example B17 A-1 1 B-2 0.3 C-2 97.7 1 Experimental Example B18 A-1 1 B-4 0.3 C-2 97.7 1 Experimental Example B19 A-1 1 B-5 0.3 C-2 97.7 1 Experimental Example B20 A-1 1 B-6 0.3 C-2 97.7 1 Experimental Example B21 A-1 1 B-3 0.3 C-2 98.2 0.5 Experimental Example B22 A-1 1 B-3 0.3 C-2 95.7 3 Experimental Example B23 A-1 1 B-3 0.3 C-2 93.7 5 Experimental Example B24 A-1 1 B-3 0.3 C-2 91.7 7 Experimental Example B25 A-1 1 B-3 0.3 C-5 97.7 1 Experimental Example B26 A-1 1 B-7 0.3 C-2 97.7 1 Experimental Example B27 A-1 7 B-3 0.3 C-2 80 12.7 Comparative Example B1 - - B-3 0.3 C-2 98.7 1 Comparative Example B2 A-1 1 - - C-2 98 1 Comparative Example B3 A-1 1 B-3 0.3 - - 98.7 Comparative Example B4 A-2 1 B-3 0.3 - - 98.7 Comparative Example B5 A-3 1 B-3 0.3 - - 98.7 Comparative Example B6 A-2 1 B-3 0.3 C-2 97.7 1 Comparative Example B7 A-3 1 B-3 0.3 C-2 97.7 1 Comparative Example B8 A-4 1 B-3 0.3 C-2 97.7 1 Comparative Example B9 A-1 1 B-3 0.3 C-6 97.7 1 Comparative Example B10 A-1 1 B-3 0.3 C-7 97.7 1 A-1: Hydrofluoric acid A-2: Ammonium fluoride A-3: Tetrabutylammonium fluoride A-4: Sodium fluoride P-1: Trimethyl phosphite P-2: Triethyl phosphite P-3: Triisopropyl phosphite P-4: Tributyl phosphite P-5: Triphenyl phosphite P-6: Tris(nonylphenyl) phosphite P-7: Methyldiethyl phosphite P-8: Triethyl phosphate B-1: Boric acid B-2: Trimethyl borate B-3: Triethyl borate B-4: Triisopropyl borate B-5: Triphenyl borate B-6: Sodium borohydride B-7: Methyldiethyl borate C-1: Ethylene glycol (boiling point: 197°C, conductivity: 1.8μS / cm) C-2: Propylene glycol monomethyl ether (boiling point: 120°C, conductivity: 1.4μS / cm) C-3: Glycerol (boiling point: 290°C, conductivity: 8.5 μS / cm) C-4: Butanol (boiling point: 118°C, conductivity: 7.8 μS / cm) C-5: Ethanol (boiling point: 78°C, conductivity: 11.7 μS / cm) C-6: Dimethyl sulfoxide (boiling point: 189°C, conductivity: 0.8μS / cm) C-7: Acetic anhydride (boiling point: 140°C, conductivity: 1.1 μS / cm) Water: Ultrapure water (boiling point: 100°C, conductivity: 12700μS / cm)

[0097] The conductivity of C-1 to C-7 and water was measured using the following method: a solution containing 99 weight percent of C-1 to C-7, water, and 1 weight percent hydrofluoric acid was calibrated with a standard solution (Mettler Toledo standard solution, 1413 μS / cm). The conductivity was then measured at 25°C using a conductivity meter (Mettler Toledo, DLS-0005). [Experimental example]

[0098] Wafers with a silicon oxide layer or a silicon nitride layer were cut into 1.5 x 1.5 cm² squares to prepare experimental samples. The samples were treated with diluted hydrofluoric acid (DHF, 100 parts by weight of water, and 1 part by weight of hydrofluoric acid) at room temperature for 1 minute to remove surface contaminants. The samples were then rinsed with water and dried. Ellipsometry equipment was then used to measure the initial thickness of the silicon oxide and nitride layers.

[0099] The experimental samples were immersed in the etching compositions of the experimental and comparative examples at 70°C and 400 rpm for 10 minutes. The samples were removed, rinsed with ultrapure water, and air-dried. Ellipsometry was then used to measure the thickness of the silicon oxide and nitride layers after etching. The etching amount was calculated based on the difference between the initial and post-etching thicknesses.

[0100] At this time, the etching amount of the silicon nitride layer and the silicon oxide layer was evaluated according to the following criteria, and the etching selectivity was expressed by calculating the ratio of the silicon oxide layer etching amount to the nitride layer etching amount. The experimental results are listed in Tables 3 and 4 below.

[0101] Silicon nitride layer etching amount evaluation standard ◎: Etching amount 30Å or more ○: Etching amount less than 30Å to more than 20Å △: Etching amount less than 20 angstroms to more than 10 angstroms Х: Etching amount less than 10Å

[0102] Silicon oxide layer etching amount evaluation standard ◎: Etching amount less than 10Å ○: Etching amount is 10 angstroms or more and less than 20 angstroms △: Etching amount is more than 20 angstroms and less than 50 angstroms Х: Etching amount 50Å or more

[0103] Evaluation of Silicon Oxide / Silicon Nitride Selectivity ◎: Select ratio 6.0 or above ○: Select ratio 3.0 or more and less than 6.0 △: Select a ratio of 2.0 or more and less than 3.0 Х: Selection ratio less than 2.0

[0104] [Table 3] Etching amount of silicon nitride layer Etching amount of silicon oxide layer Select Ratio Experimental Example A1 △ ◎ △ Experimental Example A2 ○ ◎ ○ Experimental Example A3 ◎ ◎ ◎ Experimental Example A4 ◎ ◎ ◎ Experimental Example A5 ◎ ◎ ◎ Experimental Example A6 ◎ ◎ ○ Experimental Example A7 ◎ ○ △ Experimental Example A8 ◎ ○ △ Experimental Example A9 ◎ ○ ○ Experimental Example A10 ◎ ◎ ○ Experimental Example A11 ◎ ◎ ◎ Experimental Example A12 ○ ◎ ○ Experimental Example A13 △ ◎ △ Experimental Example A14 ◎ ◎ ◎ Experimental Example A15 ◎ ○ ○ Experimental Example A16 ◎ ◎ ◎ Experimental Example A17 ◎ △ △ Experimental Example A18 ◎ ○ ◎ Experimental Example A19 ◎ ◎ ◎ Experimental Example A20 ◎ ○ ◎ Experimental Example A21 △ ◎ △ Experimental Example A22 △ ◎ △ Experimental Example A23 ○ ◎ ◎ Experimental Example A24 ◎ ◎ ◎ Experimental Example A25 ◎ ○ ○ Experimental Example A26 ◎ ○ △ Experimental Example A27 ◎ ◎ ◎ Experimental Example A28 ◎ △ △ Comparative Example A1 X ◎ X Comparative Example A2 ◎ △ X Comparative Example A3 ◎ X X Comparative Example A4 ◎ X X Comparative Example A5 ◎ X X Comparative Example A6 X ◎ X Comparative Example A7 X ◎ X Comparative Example A8 X ◎ X Comparative Example A9 ◎ △ X Comparative Example A10 X ◎ X Comparative Example A11 X ◎ X

[0105] [Table 4] Etching amount of silicon nitride layer Etching amount of silicon oxide layer Select Ratio Experimental Example B1 △ ◎ △ Experimental Example B2 ○ ◎ ○ Experimental Example B3 ◎ ◎ ◎ Experimental Example B4 ◎ ◎ ◎ Experimental Example B5 ◎ ◎ ◎ Experimental Example B6 ◎ ◎ ○ Experimental Example B7 ◎ ○ △ Experimental Example B8 ◎ ○ △ Experimental Example B9 ◎ ○ ○ Experimental Example B10 ◎ ◎ ◎ Experimental Example B11 ○ ◎ ○ Experimental Example B12 △ ◎ △ Experimental Example B13 ◎ ◎ ◎ Experimental Example B14 ◎ ○ ○ Experimental Example B15 ◎ ◎ ◎ Experimental Example B16 ◎ ○ ◎ Experimental Example B17 ◎ ◎ ◎ Experimental Example B18 ◎ ○ ◎ Experimental Example B19 △ ◎ △ Experimental Example B20 ○ △ △ Experimental Example B21 ○ ◎ ◎ Experimental Example B22 ◎ ◎ ◎ Experimental Example B23 ◎ ○ ○ Experimental Example B24 ◎ ○ △ Experimental Example B25 ◎ △ X Experimental Example B26 ◎ ◎ ◎ Experimental Example B27 ◎ △ △ Comparative Example B1 X ◎ X Comparative Example B2 ◎ △ X Comparative Example B3 ◎ X X Comparative Example B4 ◎ X X Comparative Example B5 ◎ X X Comparative Example B6 X ◎ X Comparative Example B7 X ◎ X Comparative Example B8 X ◎ X Comparative Example B9 X ◎ X Comparative Example B10 X ◎ X

[0106] Referring to Tables 3 and 4, using the compositions of the experimental examples, the silicon oxide layer was barely etched or only etched a relatively small amount, while the silicon nitride layer was significantly etched. Therefore, it can be confirmed that the compositions of the experimental examples have a high silicon nitride layer etching selectivity.

[0107] The compositions of Comparative Examples A1, A6 to A8, B1, and B6 to B8 do not contain hydrofluoric acid, resulting in only a small amount of etching of both the silicon oxide layer and the silicon nitride layer. Therefore, their selectivity is lower than that of the compositions of the comparative experimental examples.

[0108] Because the composition of Comparative Example A2 (or Comparative Example B2) does not contain a phosphite compound or a boron-containing compound, a larger amount of the silicon oxide layer is etched. Therefore, the selectivity of the composition is lower than that of the comparative experimental example.

[0109] The compositions of Comparative Examples A3 to A5 and B3 to B5 contained water as a solvent rather than a protic solvent. Consequently, both the silicon nitride layer and the silicon oxide layer were significantly etched. Consequently, their selectivity was lower than that of the compositions of the comparative experimental examples.

[0110] The composition of Comparative Example A9 contained a phosphate compound in place of the phosphite compound. Consequently, the silicon oxide layer was etched relatively heavily. Therefore, its selectivity was lower than that of the composition of the comparative experimental example.

[0111] The compositions of Comparative Examples A10 and A11, as well as Comparative Examples B9 and B10, contained an aprotic solvent. Therefore, both the silicon oxide layer and the silicon nitride layer were slightly etched. Therefore, their selectivity was lower than that of the compositions of the comparative experimental examples.

[0112] Although the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Anyone with ordinary knowledge in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications.

[0113] none

Claims

1. A composition for etching a silicon nitride layer, comprising: Hydrofluoric acid, in an amount between 0.1% and 10% by weight of the total weight of one of the compositions for etching a silicon nitride layer; a boron-containing compound or a phosphite compound; the boron-containing compound in an amount between 0.01% and 5% by weight of the total weight; the phosphite compound in an amount between 0.1% and 10% by weight of the total weight; water in an amount between 0.5% and 10% by weight of the total weight; and a protic solvent, in the remainder.

2. The composition for etching a silicon nitride layer as described in claim 1, wherein the phosphite compound is represented by the following chemical formula 1: [Chemical Formula 1] In chemical formula 1, R1 to R3 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkylaryl group having 7 to 20 carbon atoms.

3. The composition for etching a silicon nitride layer as described in claim 2, wherein in formula 1, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms.

4. The composition for etching a silicon nitride layer as described in claim 2, wherein R1 to R3 in chemical formula 1 are the same as each other.

5. The composition for etching a silicon nitride layer as described in claim 1, wherein the content of the phosphite compound is between 0.5% by weight and 5% by weight of the total weight.

6. The composition for etching a silicon nitride layer as described in claim 1, wherein the boron-containing compound comprises a borate compound.

7. The composition for etching a silicon nitride layer as claimed in claim 1, wherein the boron-containing compound is represented by the following chemical formula 2: [Chemical Formula 2] In chemical formula 2, R1 to R3 are each independently hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms.

8. The composition for etching a silicon nitride layer as described in claim 7, wherein in formula 2, R1 to R3 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms.

9. The composition for etching a silicon nitride layer as described in claim 7, wherein R1 to R3 in chemical formula 2 are the same as each other.

10. The composition for etching a silicon nitride layer as described in claim 1, wherein the content of the boron-containing compound is between 0.1% by weight and 3% by weight of the total weight.

11. The composition for etching a silicon nitride layer as claimed in claim 1, wherein the conductivity of the protic solvent is equal to or less than 10 μS / cm, and the conductivity is determined by dissolving hydrofluoric acid in a solution having the protic solvent at a weight percentage of 1.

12. The composition for etching a silicon nitride layer as described in claim 1, wherein a boiling point of the protic solvent is equal to or greater than 80°C.

13. The composition for etching a silicon nitride layer as described in claim 1, wherein the proton solvent comprises an alcohol solvent.

14. The composition for etching a silicon nitride layer as claimed in claim 1, wherein the ratio of hydrofluoric acid to water in the total weight is between 0.1 and 1.

5.

15. The composition for etching a silicon nitride layer as claimed in claim 1, wherein the composition for etching a silicon nitride layer does not include a silicon compound.

16. The composition for etching a silicon nitride layer as described in claim 1, wherein the composition for etching a silicon nitride layer does not include a basic compound.