Etching composition, insulating film etching method and semiconductor device manufacturing method using the same, and novel compound

Abstract

To provide an etching composition having a high selection ratio, which can selectively remove a nitride film while minimizing an etching rate of an oxide film, without causing problems such as particle generation having adverse effects on device characteristics.SOLUTION: The etching composition contains a compound of the formula in the figure, where A is an n-valent radical, where n is an integer from 1 to 6, L is a direct bond or hydrocarbylene, Y is selected from NR1, O, PR2 and S, where R1 and R2 are each independently hydrogen, halogen, a hydrocarbyl group, or a non-hydrocarbyl group, X and Z are each independently selected from N, O, P and S, and Ra to Rc are each independently an unshared electron pair, hydrogen, or a substituted or unsubstituted hydrocarbyl group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an etching composition, particularly an etching composition with a high selectivity that can minimize the etching rate of an oxide film and selectively remove a nitride film, an etching method for an insulating film using the above composition, and a method for manufacturing a semiconductor device to which the above etching method is applied. Further, the present invention relates to a silane compound suitable for use as an additive in an etching composition.

Background Art

[0002] Oxide films such as silicon oxide films (SiO2) and nitride films such as silicon nitride films (SiNx) are typical insulating films, and these silicon oxide films or silicon nitride films are used alone or with one or more layers alternately laminated in the semiconductor manufacturing process. Further, such oxide films and nitride films are also used as hard masks for forming conductive patterns such as metal wirings.

[0003] In the wet etching process for removing the above nitride film, a mixture of phosphoric acid and deionized water is generally used. The above deionized water is added to prevent a decrease in the etching rate and a change in the etching selectivity of the nitride film with respect to the oxide film, but there is a problem that defects occur in the nitride film etching and removal process even with a minute change in the amount of supplied deionized water. Further, phosphoric acid is a strong acid and has corrosiveness, making it difficult to handle.

[0004] To solve this problem, conventionally, a technique of removing a nitride film using an etching composition containing hydrofluoric acid (HF) or nitric acid (HNO3) in phosphoric acid (H3PO4) has been known, but this has resulted in inhibiting the etching selectivity between the nitride film and the oxide film. Further, a technique of using an etching composition containing phosphoric acid and silicate or silicic acid has also been known, but silicic acid and silicate generate particles that may affect the substrate, and thus have the problem of being unsuitable for the semiconductor manufacturing process.

[0005] However, when phosphoric acid is used in a wet etching process for removing such a nitride film, not only the nitride film but also the SOD oxide film is etched due to a decrease in the etching selectivity between the nitride film and the oxide film, making it difficult to adjust the effective field oxide height (EFH). Therefore, it may not be possible to ensure a sufficient wet etching time for removing the nitride film, additional processes may be required, which induces changes in device characteristics and adversely affects device characteristics.

[0006] Therefore, there is a need for an etching composition with a high selectivity that does not have problems such as particle generation while selectively etching a nitride film with respect to an oxide film in a semiconductor manufacturing process.

[0007] On the other hand, a silane-based additive, which is an additive added to a conventional etching composition, has a problem that its solubility is low and an appropriate solubility cannot be ensured. As a result, there are problems such as precipitation of particles in the etching composition and abnormal growth of the substrate. Such particles remain on the silicon substrate and cause defects in the devices realized on the substrate, or remain in the equipment used in the etching or cleaning process and cause equipment failures. Summary of the Invention Problems to be Solved by the Invention

[0008] One object of the present invention is to provide a high-selectivity etching composition that minimizes the etching rate of an oxide film, can selectively remove a nitride film, and does not have problems such as generation of particles that adversely affect device characteristics.

[0009] Another object of the present invention is to provide an etching composition having excellent storage stability.

[0010] Still, another object of the present invention is to provide a method for etching an insulating film using the above etching composition and a method for manufacturing a semiconductor device.

Means for Solving the Problems

[0011] The present invention aims to provide an etching composition. According to an embodiment of the present invention, there is provided an etching composition containing phosphoric acid, phosphoric anhydride, a compound represented by the following Chemical Formula 1, and a silane compound containing one or more Si atoms (excluding the compound represented by Chemical Formula 1).

Chemical Formula

[0012] In the above Chemical Formula 1, A is an n-valent radical, n is an integer from 1 to 6, L is a direct bond or hydrocarbylene, Y is selected from NR 1 , O, PR 2 and S, where R 1 and R 2 are each independently hydrogen, halogen, a substituted or unsubstituted hydrocarbyl group, or a substituted or unsubstituted non-hydrocarbyl group, X and Z are each independently selected from N, O, P, and S, and R a ~R c are each independently a lone pair of electrons, hydrogen, or a substituted or unsubstituted hydrocarbyl group.

[0013] R a ~R c are each independently a lone pair of electrons, hydrogen, a substituted or unsubstituted C1-C 20 alkyl group, a substituted or unsubstituted C6-C 20 aryl group, and a functional group represented by the following formula.

Chemical Formula

[0014] Here, R4 ~R 9 Each of them is independently hydrogen, a substituted or unsubstituted hydrocarbyl group, or a substituted or unsubstituted non-hydrocarbyl group. For example, the above R 4 ~R 9 may all be hydrogen. Also, L1 is a direct bond or a hydrocarbylene. For example, L1 may be an alkylene of C1-C 10 .

[0015] In the above Chemical Formula 1, A may be a hydrocarbyl, a hydrocarbylene, a radical with a bonding site at N, a radical with a bonding site at O, a radical with a bonding site at S, or a radical with a bonding site at P.

[0016] As an example, the above A is an alkyl of C1-C 20 or an aryl of C6-C 20 . A may exist alone or may be a monovalent radical that is linked to R a through a hetero element of O, N, or S to form a ring.

[0017] As an example, the above A is *-(CH2) p R 10 [where p is an integer from 0 to 3, and R 10 is hydrogen (provided that p is not 0), halogen (provided that p is not 0), a substituted or unsubstituted C1-C 20 alkyl, a substituted or unsubstituted C6-C 20 aryl, and a substituted or unsubstituted C1-C 20 alkyl C1-C 20 alkoxy, or *-(CH=CH) m N=(where m is an integer from 1 to 3 and is linked to R a through N to form a ring), or, for example, the above A is *-CH3,

Chemical formula

[0018] As an example, the above A is [Chemical formula] (where q is an integer from 0 to 4) and may be a divalent to hexavalent radical, for example, [Chemical formula] may also be.

[0019] As an example, the radical where the binding site is N is *-NR 11 R 12 、*-NR 13 -*, [Chemical formula] 、*-NR 14 CSNR 15 -*, *-NR 16 CONR 17 -*, *-NR 18 L2NR 19 -*, *-NR 20 CONR 21 L3NR 22 CONR 23 -*, *-NR 24 CONL4L5NCONR 25 -*, [Chemical formula] or [Chemical formula] may also be, where R 11 ~R 26 are each independently hydrogen, a C1-C 20 alkyl group, or a C6-C 20 aryl group, and L2 to L6 are C1-C20 The alkylene of 20 , the arylene of 31 (OR 32 ) r wherein R 31 and R 32 are each independently a C1-C 20 alkylene group, r is an integer from 1 to 5, and L7 is a direct bond or (CH2) s NR 33 NR 34 wherein R 33 and R 34 are each independently hydrogen, a C1-C 20 alkyl group, or a C6-C 20 aryl group, and s is an integer from 1 to 5. For example, a radical with a binding site at N is *-NR 11 R 12 , *-NR 13 -*, or [Chemical formula] , more preferably [Chemical formula] wherein R 11 ~R 13 are each independently hydrogen, a C1-C 20 alkyl group, or a C6-C 20 aryl group.

[0020] As an example, the radical with the above binding site at O may be *-O-*.

[0021] As an example, the radical with the above binding site at S is *-S-*, *-S-S-*, [Chemical formula] , or [Chemical formula] may also be.

[0022] The radical in which the above-mentioned bonding site is P is

Chem.

Chem.

Chem.

Chem.

[0023] In the above Chemical Formula 1, the above L may be a C1-C 10 alkylene.

[0024] The compound represented by the above Chemical Formula 1 may be a compound selected from the following Structural Formulas 1 to 8.

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

[0025] The silane compound containing one or more of the above Si atoms may be a silane compound represented by the following Chemical Formula 2.

Chem.

[0026] In the above Chemical Formula 2, R 51 ~R 54 are each independently hydrogen, a C1-C 20 hydrocarbyl group, or a C1-C 20 heterohydrocarbyl group, and R 51 ~R 54 each exist or are cyclic and linked to each other via two or more hetero elements.

[0027] The etching composition according to one embodiment may further contain an ammonium salt.

[0028] The etching composition according to one embodiment may contain 0.001 to 5% by weight of the compound represented by the above Chemical Formula 1 based on the total weight of the etching composition.

[0029] The above etching composition according to one embodiment may be an etching composition containing 70 to 90% by weight of phosphoric acid, 1 to 20% by weight of metaphosphoric acid, 0.001 to 5% by weight of the compound represented by Chemical Formula 1, 0.005 to 1% by weight of a silane compound containing one or more Si atoms (excluding the compound represented by Chemical Formula 1), and the balance being water.

[0030] As an example, a method for etching an insulating film using an etching composition is provided.

[0031] As another example, a method for manufacturing a semiconductor device including the method for etching the insulating film is provided.

[0032] As still another example, a compound represented by the following Chemical Formula 1 is provided.

Chemical formula

[0033] In the above Chemical Formula 1, A is an n-valent radical, n is an integer from 1 to 3, L is a direct bond or a C1-C3 hydrocarbylene, Y is selected from O and S, X and Z are independently selected from N, O, and S, and R a and R b are independently a lone pair of electrons, hydrogen, a substituted or unsubstituted hydrocarbyl group, and R c is a substituted or unsubstituted hydrocarbyl group.

[0034] As an example, the above R c may be a C1-C 20 alkyl group, a C6-C 20 aryl group, or a functional group represented by the following formula.

Chemical formula

[0035] As an example, the above R 4 ~R 9 are all hydrogen, and L1 may be a direct bond or a C1-C5 alkylene.

[0036] As an example, the above A is C1-C20 is alkyl or C6-C 20 aryl, and A may exist alone or be a monovalent radical linked to R via a hetero element of O, N or S to form a ring. Also, the above A is a a trivalent radical of

Chemical formula

[0037] As an example, A is

Chemical formula

Chemical formula

[0038] For example, it may be a compound having any one of the structural formulas of the following formulas (2) to (5).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Advantages of the Invention

[0039] The etching composition according to the present invention has a high etching selectivity of the nitride film with respect to the oxide film.

[0040] Further, when the etching composition of the present invention is used, it is possible to prevent damage to the film quality of the oxide film and deterioration of electrical characteristics due to etching of the oxide film during removal of the nitride film, and to prevent generation of particles, thereby improving the element characteristics.

Brief Description of the Drawings

[0041]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0042] The present invention provides an etching composition, particularly an etching composition having a high selectivity capable of minimizing the etching rate of an oxide film and selectively removing a nitride film, and excellent storage stability.

[0043] The etching composition of the present invention contains phosphoric acid, phosphoric anhydride, an etching solution additive, and a silane compound containing one or more Si atoms (excluding the compound represented by Chemical Formula 1).

[0044] The above phosphoric acid reacts with silicon nitride to etch the nitride film, and the above phosphoric acid reacts with silicon nitride as shown in the following formula (1). 3Si3N4 + 27H2O + 4H3PO4 → 4(NH4)3PO4 + 9SiO2H2O (1)

[0045] For example, the phosphoric acid may be an aqueous phosphoric acid solution containing phosphoric acid at a concentration of 75 to 85%. The water used in the aqueous phosphoric acid solution is not particularly limited, but deionized water can be used.

[0046] The phosphoric acid can be contained in a content of 70 to 90% by weight based on the total weight of the etching composition. When it is less than 70% by weight, there is a problem that the nitride film is not easily removed, and when it exceeds 90% by weight, a high selectivity of the nitride film with respect to the oxide film cannot be obtained.

[0047] The etching composition of the present invention contains an etching solution additive. Examples of the etching solution additive include a compound represented by the following Chemical Formula 1.

Chemical Formula

[0048] In Chemical Formula 1 above, Y can be selected from NR 1 , O, PR 2 , and S. Here, R 1 and R 2 may each independently be hydrogen, a halogen, a substituted or unsubstituted hydrocarbyl group, or a non-hydrocarbyl group. For example, the hydrocarbyl group may be a substituted or unsubstituted C1-C 20 alkyl group such as a methyl group or an ethyl group, a substituted or unsubstituted C6-C 20 aryl group such as a benzyl group, a substituted or unsubstituted C1-C 20 alkoxy group, or a substituted or unsubstituted C1-C 20 alkyl C1-C 20 alkoxy group, etc.

[0049] In Chemical Formula 1 above, X and Z can be independently selected from N, O, P, and S.

[0050] At this time, in the above Chemical Formula 1, R linked to the above X and Z a ~R c may each independently be a lone pair, hydrogen, or a substituted or unsubstituted hydrocarbyl group. When the above R a ~R c is a substituted or unsubstituted hydrocarbyl group, it may be a C1-C 20 alkyl group, or a C6-C 20 aryl group, or a functional group represented by the following formula.

Chemical formula

[0051] Here, R 4 ~R 9 may each independently be hydrogen, a substituted or unsubstituted hydrocarbyl group, or a non-hydrocarbyl group. The above hydrocarbyl group or non-hydrocarbyl group may be a substituted or unsubstituted C1-C 20 hydrocarbyl group, a C1-C 20 alkoxy group, a carboxy group, a carbonyl group, a nitro group, a tri C1-C 20 alkylsilyl group, a phosphoryl group, or a cyano group. The above substituted or unsubstituted C1-C 20 hydrocarbyl group may be a substituted or unsubstituted C1-C 20 alkyl group, or a substituted or unsubstituted C6-C 20 aryl group. The above substitution may include, but is not limited to, substitution with a halogen. As an example, the above R 4 ~R 9 may all be hydrogen.

[0052] L1 may be a direct bond or a hydrocarbylene, specifically, it may be a C1-C 10 hydrocarbylene. For example, it may be a C1-C 10 alkylidene, more specifically, a C1-C5 alkylidene, a C1-C3 alkylidene, etc.

[0053] As an example, the above R a and R b are a non-bonding electron pair, hydrogen, a substituted or unsubstituted C1-C 20 alkyl group or a C6-C 20 aryl group, and R c is a non-bonding electron pair, hydrogen, a substituted or unsubstituted C1-C 20 alkyl group, a substituted or unsubstituted C6-C 20 aryl group, or a functional group represented by the following formula. [Chemical formula]

[0054] Here, R 4 to R 9 and L1 are as defined above.

[0055] In the above Chemical formula 1, L may be a direct bond or a hydrocarbylene. Specifically, the above L may be a C1-C 10 hydrocarbylene, for example, a C1-C 10 alkylene, a C1-C3 alkylene, etc.

[0056] In the above Chemical formula 1, A is an n-valent radical, and n is an integer from 1 to 6. For example, the above A may be a hydrocarbyl, a hydrocarbylene, a radical with a bonding site at N, a radical with a bonding site at O, a radical with a bonding site at S, or a radical with a bonding site at P.

[0057] Specifically, the above A may be a monovalent hydrocarbyl with n being 1. More specifically, the above A may be a substituted or unsubstituted C1-C 20 alkyl such as methyl, ethyl, etc., or a substituted or unsubstituted C6-C 20 aryl such as benzyl.

[0058] Furthermore, A may be a hydrocarbylene. When A is a hydrocarbylene, it goes without saying that A can exist alone, or it can exist by forming a ring through a hetero element such as O, N, or S and being linked to R a For example, it can exist by forming a ring through being linked to R via a hetero element N like *-CH=CHN=R a For example, it can exist by forming a ring through being linked to R via a hetero element N like *-CH=CHN=R a For example, it can exist by forming a ring through being linked to R via a hetero element N like *-CH=CHN=R

[0059] As an example, the above A may be

Chemical formula

[0060] As another example, the above A is *-(CH=CH) m N-, and it can form a ring by being linked to R via N. At this time, the above N can have one substituent such as hydrogen or halogen. When having the substituent, it can be linked to R by a single bond, and when not having the substituent, it can be linked to R by a double bond. Here, m is an integer from 1 to 3. a For example, the above A is *-(CH=CH) a N-, and it can form a ring by being linked to R via N. At this time, the above N can have one substituent such as hydrogen or halogen. When having the substituent, it can be linked to R by a single bond, and when not having the substituent, it can be linked to R by a double bond. Here, m is an integer from 1 to 3. a For example, the above A is *-(CH=CH)

[0061] Specific examples of the above A include *-CH3,

Chemical formula

Chemical formula

[0062] Further, the above A is [Chemical formula] It may be a divalent to hexavalent radical such as this. At this time, the above q is an integer from 0 to 4. Specifically, when q is 0, it is a divalent radical; when q is 1, it is a trivalent radical; when q is 2, it is a tetravalent radical; when q is 4, it is a hexavalent radical.

[0063] The above A may also be a radical whose bonding site is N. For example, when n is 1, the radical whose bonding site is N may be *-NR 11 R 12 and when n is 2, it may be *-NR 13 -*, *-NR 14 CSNR 15 -*, *-NR 16 CONR 17 -*, *-NR 18 L2NR 19 -*, *-NR 20 CONR 21 L3NR 22 CONR 23 -*, *-NR 24 CONL4L5NCONR 25 -* etc. can be cited, and when n is 3 [Chemical formula] , [Chemical formula] etc. can be cited. Also, when n is 4 [Chemical formula] can be cited.

[0064] Here, R 11 ~R 26 are independently hydrogen, a C1-C 20 alkyl group, or a C6-C 20 aryl group, and L2 to L6 are C1-C 20 alkylene, C6-C 20 arylene, or R 31 (OR 32 ) r (wherein R 31 and R 32 are independently a C1-C 20 alkylene group, and r is an integer from 1 to 5), and L7 is a direct bond or (CH2) s NR 33 NR 34 wherein R 33 and R 34 are independently hydrogen, a C1-C 20 alkyl group, or a C6-C 20 aryl group, and s is an integer from 1 to 5.

[0065] Further, the above A may be a radical having a bonding site of O. For example, the radical having a bonding site of O may be a divalent radical such as *-O-*.

[0066] Further, the above A may be a radical having a bonding site of S. For example, the radical having a bonding site of S may be a divalent radical such as *-S-*, *-S-S-*,

Chemical formula

Chemical formula

[0067] Further, the above A may be a radical having a bonding site of P. The radical having a bonding site of P is

Chemical formula

[0068] In the above Chemical Formula 1, Y can be selected from O, P, and S, and X and Z can each independently be selected from N, O, P, and S.

[0069] More specifically, as the compound represented by the above Chemical Formula 1, it may be any one of the compounds represented by the following Structural Formulas 1 to 8, for example. [Chemistry] …(1), [Chemistry] …(2), [Chemistry] …(3), [Chemistry] …(4), [Chemistry] …(5), [Chemistry] …(6),

Chem.

Chem.

[0070] The compound of Chemical Formula 1 as described above binds to the surface of the oxide film to protect the oxide film, and can minimize the etching of the oxide film while the nitride is etched in the etching composition. Further, the compound of Chemical Formula 1 as described above can significantly increase the etching selectivity of the nitride film with respect to the oxide film as compared with a commonly used single-chain silicon additive. Furthermore, the structural stability of the active silicon-based additive in the etching composition can be improved, and the etching rate of the silicon oxide film can also be continuously maintained. In addition, the compound of Chemical Formula 1 has a polar functional group in the molecule, has high solubility in polar solvents such as water and aqueous phosphoric acid solution, and can suppress the generation of particles during the etching process.

[0071] In the present invention, the compound represented by Chemical Formula 1 that can be used as an additive to the etching composition can effectively protect the silicon oxide film even when added in a small amount to the etching composition, and thus can increase the etching selectivity of the nitride film with respect to the oxide film.

[0072] The compound represented by the above Chemical Formula 1 can be added in a content of 0.001 to 5% by weight based on the total weight of the etching composition. When the addition amount of the compound represented by the above Chemical Formula 1 is less than 0.001% by weight, it is difficult to obtain the effect of high selectivity of the nitride film with respect to the oxide film. When it exceeds 5% by weight, the compound may gel. For example, the compound represented by the above Chemical Formula 1 can be included in a content within the range of 0.001, 0.005, 0.007, 0.01, 0.03, 0.05, 0.07, 0.1, 0.15 or 0.2% by weight or more, and 5, 4.5, 4, 3.5, 3, 2.5, 2 or 1% by weight or less based on the total weight of the etching composition.

[0073] The compound represented by Chemical Formula 1 used as an additive to the etching composition is characterized by low solubility. When a silane-based additive that does not ensure an appropriate solubility is used in the etching composition, or when the composition ratio is not adjusted to an appropriate level, precipitation and abnormal growth of silicon-based particles may occur in the etching composition. Such particles may remain on the silicon substrate and cause defects in the elements realized on the substrate, or may remain in the equipment (for example, filters) used in the etching or cleaning process and cause equipment failures.

[0074] The present invention includes metaphosphoric acid together with the compound represented by the above Chemical Formula 1. The metaphosphoric acid is not particularly limited, but those obtained by completely removing the moisture in phosphoric acid can be used. The metaphosphoric acid may be any of orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid with P3 or more, and metaphosphoric acid as long as the moisture is removed, and any one of these can be used alone or in combination of two or more.

[0075] Although not particularly limited, the metaphosphoric acid can be obtained by heating phosphoric acid at a temperature of 180 to 220°C to remove water. In the present invention, by using metaphosphoric acid together with the compound of Chemical Formula 1, the phenomenon of precipitation without being dissolved by the hydrolysis and polycondensation reaction of the silane-based additive due to the remaining water can be suppressed.

[0076] Although not particularly limited, after mixing the above-mentioned phosphoric anhydride and the compound of Chemical Formula 1, it can be introduced into an aqueous phosphoric acid solution. For this purpose, after adding the compound of Chemical Formula 1 to the above-mentioned phosphoric anhydride, it can be mixed by heating to a temperature of 30 to 300 °C to dissolve.

[0077] The above-mentioned phosphoric anhydride is preferably contained in a content of 1 to 20% by weight. If it is less than 1% by weight, the compound of Chemical Formula 1 may precipitate without being dissolved, and if it exceeds 20% by weight, the selectivity for the silicon nitride film may decrease.

[0078] The etching composition of the present invention suppresses etching of the oxide film by adding the compound represented by Chemical Formula 1 as described above, thereby improving the selectivity for the nitride film, suppressing the formation of silica, and obtaining the effects of suppressing the generation of particles and improving storage stability.

[0079] On the other hand, in the above Formula 1, SiO2H2O may generally deposit on the surface of the oxide film and a phenomenon of abnormal growth that may increase the thickness of the oxide film may appear. In particular, when the etching process of the nitride film is accumulated in the etching composition, the concentration of SiO2H2O in the etching composition may increase, and the increase in the concentration of such SiO2H2O may increase the degree of occurrence of abnormal growth. That is, in the initial etching composition, even if abnormal growth due to SiO2H2O does not occur, the frequency of occurrence of abnormal growth increases as the number of accumulated processes increases. In contrast, when the compound represented by Chemical Formula 1 according to the present invention is included, the occurrence of such a phenomenon of abnormal growth can be suppressed.

[0080] The etching composition of the present invention contains a silane compound containing one or more Si atoms. The above silane compound is different from the compound according to the above Chemical Formula 1. The above silane compound may be a silane compound represented by the following Chemical Formula 2.

Chemical formula

[0081] In the above Chemical formula 2, R 51 ~R 54 are each independently hydrogen, a C1-C 20 hydrocarbyl, a C1-C 20 heterohydrocarbyl, and R 51 ~R 54 may each be present or may be cyclic and linked to each other via two or more heteroatoms. For example, they may be hydrogen, a C1-C 20 alkyl or a C1-C 20 heteroalkyl, etc. At this time, the above heteroatoms are not particularly limited and may be, for example, N, S, O, P, etc.

[0082] The silane compound represented by the above Chemical formula 2 can be contained in a content of 0.005 to 1% by weight based on the total weight of the etching composition.

[0083] Furthermore, an ammonium salt can also be added to the etching composition of the present invention. The ammonium salt can prevent the gelation of the etching composition and can be added in a content of 0.001 to 10% by weight based on the total weight. If less than 0.001% by weight is added, the effect of improving the physical properties of reducing gelation is slight, and if more than 10% by weight is added, the ammonium salt may cause gelation.

[0084] As the above ammonium salt, a compound having an ammonium ion and commonly used in the field to which the present invention belongs can also be preferably used in the present invention. Such ammonium salts include, but are not limited to, for example, aqueous ammonia, ammonium chloride, ammonium acetate, ammonium phosphate, ammonium peroxydisulfate, ammonium sulfate, ammonium fluoride, etc. Needless to say, any one of these can be used alone, and two or more of them can also be used in combination.

[0085] Furthermore, the etching composition of the present invention can further contain any additive commonly used in the art to further improve the etching performance. Examples of the additive include a surfactant, a sequestering agent, a corrosion inhibitor, and the like.

[0086] In the etching composition of the present invention, the balance is a solvent. The solvent is not particularly limited, and may be water.

[0087] The etching composition of the present invention is used to selectively etch and remove a nitride film from a semiconductor device including an oxide film and a nitride film, and the nitride film can include a silicon nitride film, for example, a SiN film, a SiON film, and the like.

[0088] The oxide film may also be at least one film selected from the group consisting of a silicon oxide film, for example, a SOD (Spin On Dielectric) film, an HDP (High Density Plasma) film, a thermal oxide film, a BPSG (Borophosphate Silicate Glass) film, a PSG (Phospho Silicate Glass) film, a BSG (Boro Silicate Glass) film, a PSZ (Polysilazane) film, an FSG (Fluorinated Silicate Glass) film, an LPTEOS (Low Pressure Tetra Ethyl Ortho Silicate) film, a PETEOS (Plasma Enhanced Tetra Ethyl Ortho Silicate) film, an HTO (High Temperature Oxide) film, an MTO (Medium Temperature oxide) film, a USG (Undopped Silicate Glass) film, a SOG (Spin On Glass) film, an APL (Advanced Planarization Layer) film, an ALD (Atomic Layer Deposition) film, a PE-oxide film (Plasma Enhanced oxide), an O3-TEOS (O3-Tetra Ethyl OrthoS ilicate) film, and combinations thereof.

[0089] The etching process using the etching composition of the present invention can be carried out by a wet etching method, for example, a dipping method, a spraying method, or the like.

[0090] Examples of the etching process using the etching composition of the present invention are schematically shown in FIGS. 1 and 2. FIGS. 1 and 2 are process cross-sectional views showing an element isolation process of a flash memory element as an example.

[0091] First, as shown in FIG. 1, after forming a tunnel oxide film 11, a polysilicon film 12, a buffer oxide film 13, and a pad nitride film 14 on a substrate 10 in sequence, the polysilicon film 12, the buffer oxide film 13, and the pad nitride film 14 are selectively etched to form a trench. Subsequently, after forming an SOD oxide film 15 until the trench is gap-filled, a CMP process is performed on the SOD oxide film 15 using the pad nitride film 14 as a polishing stop film.

[0092] Next, as shown in FIG. 2, after removing the pad nitride film 14 by wet etching using a phosphoric acid solution, the buffer oxide film 13 is removed through a cleaning process. Thereby, an element isolation film 15A is formed in the field region.

[0093] The process temperature in the etching process may be in the range of 50 to 300 °C, preferably in the range of 100 to 200 °C, more preferably in the range of 156 °C to 163 °C, and the appropriate temperature can be changed as needed in consideration of other processes and other factors.

[0094] Thus, according to the method for manufacturing a semiconductor device including an etching process performed using the etching composition of the present invention, when a nitride film and an oxide film are alternately laminated or mixed, selective etching of the nitride film with respect to the oxide film is possible. In addition, generation of particles, which was a problem in the conventional etching process, can be prevented, and the stability and reliability of the process can be ensured.

[0095] Therefore, such a method can be efficiently applied to some processes in the semiconductor device manufacturing process where selective etching of the nitride film with respect to the oxide film is required.

Example

[0096] Hereinafter, the present invention will be described in more detail with reference to examples. The following examples show an example of the present invention, and the present invention is not limited thereby.

[0097] Synthesis Example 1 7.0 g of methyl (3-triethoxysilyl) propyl carbonate, 3.7 g of triethanolamine, 35 ml of tetrahydrofuran, and 0.2 g of sodium hydroxide were placed in a 100 mL round-bottom flask, and then the temperature was raised to 50 °C and stirred for 4 hours.

[0098] Thereafter, tetrahydrofuran was removed under reduced pressure conditions to obtain a white solid.

[0099] 5.1 g of 3-(2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-yl)propyl methyl carbonate (Additive 2) purified through an ethyl acetate re-slurry was synthesized from the white solid obtained above.

Chemical Structure

[0100] 1 H-NMR (CDCl3) 4.21 (t, 2H), 3.89 (t, 6H), 3.79 (s, 3H), 2.55 (t, 6H), 1.60 (m, 2H), 0.58 (t, 2H)

[0101] Synthesis Example 2 7.8 g of N-(3-(triethoxysilyl)propyl)-1H-imidazole-1-carboxamide, 3.7 g of triethanolamine, 35 ml of tetrahydrofuran, and 0.2 g of sodium hydroxide were placed in a 100 ml round-bottom flask, and then the temperature was raised to 50 °C and stirred for 4 hours.

[0102] Thereafter, tetrahydrofuran was removed under reduced pressure conditions to obtain a yellow solid.

[0103] 5.5 g of N-(3-(2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-yl)propyl)-1H-imidazole-1-carboxamide (Additive 3) purified through an ethyl acetate re-slurry was synthesized from the yellow solid obtained above.

Chemical Structure

[0104] 1 H-NMR (CDCl3) δ 8.14 (s, 1H), 7.46 (d, 1H), 7.14 (d, 1H), 3.89 (t, 6H), 3.18 (t, 2H), 2.55 (t, 6H), 1.60 (m, 2H), 0.58 (t, 2H)

[0105] Synthesis Example 3 7.7 g of methyl (3-(triethoxysilyl)propyl)carbamodithioate, 3.7 g of triethanolamine, 35 ml of tetrahydrofuran, and 0.2 g of sodium hydroxide were placed in a 100 ml round-bottom flask, and then the temperature was raised to 50 °C and stirred for 4 hours.

[0106] Thereafter, tetrahydrofuran was removed under reduced pressure conditions to obtain a yellow solid.

[0107] 5.8 g of methyl (3-(2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-yl)propyl)carbamodithioate (Additive 4) was synthesized from the above yellow solid via an ethyl acetate slurry. [Chemical formula]

[0108] 1 H-NMR (CDCl3) δ 3.89 (t, 6H), 2.87 (t, 2H), 2.55 (m, 9H), 1.60 (m, 2H), 0.58 (t, 2H)

[0109] Synthesis Example 4 22.2 g of nitrilotris(ethane-2,1-diyl)tris((3-(triethoxysilyl)propyl)carbamate), 11.1 g of triethanolamine, 35 ml of tetrahydrofuran, and 0.6 g of sodium hydroxide were placed in a 100 ml round-bottom flask, and then the temperature was raised to 50 °C and stirred for 4 hours.

[0110] Thereafter, tetrahydrofuran was removed under reduced pressure conditions to obtain a yellow solid.

[0111] The above yellow solid was purified through an ethyl acetate slurry to synthesize 11.1 g of nitrilotris(ethane-2,1-diyl)tris((3-(2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-yl)propyl)carbamate (Additive 5).

Chemical formula

[0112] 1 H-NMR (CDCl3) 4.35 (t, 6H), 3.89 (t, 18H), 3.18 (t, 6H), 2.97 (t, 6H), 2.55 (t, 18H), 1.60 (m, 6H), 0.58 (t, 6H)

[0113] Example 1 A substrate was provided on which a silicon oxide film (SiOx) with a thickness of 500 Å (angstrom) and a silicon nitride film (SiN) with a thickness of 5000 Å were formed by vapor deposition on a semiconductor wafer.

[0114] 3-Aminopropylsilanetriol was added to anhydrous phosphoric acid at 120 °C and dissolved to produce a mixture. Then, after adding the above mixture to phosphoric acid, diphenyl carbonate (Additive 1) of the following structural formula was added to produce an etching composition.

Chemical formula

[0115] Thereby, as shown in Table 1 below, an etching composition was produced that contained 0.5 wt% of 3-aminopropylsilanetriol, 10 wt% of anhydrous phosphoric acid, and 0.1 wt% of Additive 1 in 85 wt% of phosphoric acid, with the balance being water.

[0116] The above etching composition was placed in a round-bottom flask and heated for 60 minutes. After raising the temperature to 158 °C, the above silicon wafer was immersed, and the etching process was carried out by immersing it for 720 seconds and 6000 seconds.

[0117] After selectively etching the surface of the silicon wafer on which the pattern was formed, the film thicknesses of the silicon oxide film and the nitride film before and after etching were measured using ellipsometry of a thin film thickness measuring device (NANO VIEW, SEMG-1000), and from this, the etching rate of the silicon oxide film (SiO E / R, Å / min), the etching rate of the silicon nitride film (SiN E / R, Å / min), and the selectivity were calculated. The results are shown in Table 1 below.

[0118] The selectivity represents the ratio of the etching rate of the nitride film to the etching rate of the oxide film, and is the value obtained by dividing the difference between the initial value and the film thickness after the etching treatment by the etching time (minutes).

[0119] Examples 2 to 5 The etching process was performed in the same manner as in Example 1, except that Additives 2 to 5 were used instead of Additive 1, and the etching rate of the silicon oxide film, the etching rate of the silicon nitride film, and the selectivity were calculated. The results are shown in Table 1 below.

[0120] Comparative Example 1 3-Aminopropylsilanetriol was added to phosphoric acid to produce an etching composition.

[0121] As a result, an etching composition containing 0.5% by weight of 3-aminopropylsilanetriol in 85% by weight of phosphoric acid and the balance being water was produced as shown in Table 1 below.

[0122] Using the above-produced etching composition, the etching process was performed in the same manner as in Example 1.

[0123] As a result, the etching rate of the silicon oxide film, the etching rate of the silicon nitride film, and the selectivity were calculated, and the results are shown in Table 1 below.

[0124] Comparative Example 2 3-Aminopropylsilanetriol was added to anhydrous phosphoric acid at 120 °C and dissolved to produce a mixture. Then, the mixture was added to phosphoric acid to produce an etching composition.

[0125] As a result, as shown in Table 1 below, an etching composition was produced that contained 0.5% by weight of 3-aminopropylsilanetriol, 10% by weight of anhydrous phosphoric acid, and the balance was water in 85% by weight of phosphoric acid.

[0126] Using the above-produced etching composition, an etching process was performed in the same manner as in Example 1.

[0127] [Evaluation of Etching Rate and Selectivity for Silicon Oxide Film and Nitride Film] As a result, the etching rate of the silicon oxide film, the etching rate of the silicon nitride film, and the selectivity were calculated, and the results are shown in Table 1 below.

[0128]

Table 1

[0129] As can be seen from Table 1, the etching compositions of Examples 1 to 5 further containing Additives 1 to 5 with respect to the etching composition showed a significantly higher etching selectivity than the etching compositions of Comparative Examples 1 and 2. Also, in terms of the etching rate (SiN E / R) of the silicon nitride film, it showed a significantly superior effect compared to the etching compositions of Comparative Examples 1 and 2, and it was confirmed that an etching composition optimized for the etching process of the silicon nitride film could be provided.

[0130] From the above results, it was confirmed that when using the etching composition containing the compound of Chemical Formula 1 provided in the present invention as an additive, the etching rate, etching selectivity, and etching stability of the silicon nitride film can be improved, and the efficiency of the etching process can be improved.

[0131] [Confirmation of Temporal Change of Etching Composition] After storing the etching compositions of Comparative Example 1 and Example 1 above at about 70°C for a certain period of time, a re-etching test was performed on the etching compositions under the same conditions every 7 days, and the results are shown in Table 2 below.

[0132] [Table 2]

[0133] As can be seen from Table 2 above, after 21 days, the etching composition of Comparative Example 1 showed a significant decrease in the etching rate (SiN E / R) and the selectivity ratio. In contrast, it can be seen that the etching composition of Example 1 further mixed with Additive 1 showed almost no change in the etching rate (SiN E / R, SiO E / R) and the selectivity ratio. From the above results, it goes without saying that the etching composition according to an example of the present invention is excellent in etching rate and selectivity ratio, and because of its excellent storage stability, it can be seen that excellent etching characteristics can be maintained even during long-term storage.

[0134] The above results indicate that due to the effect of the structural stability of Additive 1, the role of suppressing etching of the silicon oxide film can be maintained without the occurrence of phenomena such as decomposition or abnormal growth between 3-aminopropylsilanetriol.

Claims

1. An etching composition for a silicon nitride film, comprising phosphoric acid, phosphoric anhydride, a compound represented by the following Chemical Formula 1, and a silane compound containing one or more Si atoms (excluding the compound represented by Chemical Formula 1). 【Chemical Formula 1】 …[Chemical Formula 1] In the above Chemical Formula 1, A is an n-valent radical, and n is an integer from 1 to 6, L is a direct bond or hydrocarbylene, Y is selected from NR １ , O, PR ２ , and S, where R １ and R ２ are each independently hydrogen, halogen, a substituted or unsubstituted hydrocarbyl group, or a substituted or unsubstituted non-hydrocarbyl group, X and Z are each independently selected from N, O, P, and S, R ａ ~R ｃ are each independently a lone pair, hydrogen, or a substituted or unsubstituted hydrocarbyl group.

2. R ａ ~R ｃ are each independently a lone pair, hydrogen, a substituted or unsubstituted C １ -C ２０ alkyl group, a substituted or unsubstituted C ６ -C ２０ aryl group, and a functional group represented by the following formula, and is the etching composition for a silicon nitride film according to Claim 1. 【Chemical Formula 2】 (Here, R ４ ~R ９ are each independently hydrogen, a substituted or unsubstituted hydrocarbyl group, or a substituted or unsubstituted non-hydrocarbyl group, L １ is a direct bond or hydrocarbylene.)

3. The aforementioned R ４ to R ９ are all hydrogen. The etching composition for a silicon nitride film according to claim 2.

4. The aforementioned L １ is C １ - C １０ The etching composition for a silicon nitride film according to claim 2, which is an alkylene of.

5. The aforementioned A is a hydrocarbyl, hydrocarbylene, radical with a bonding site of N, radical with a bonding site of O, radical with a bonding site of S, or radical with a bonding site of P. The etching composition for a silicon nitride film according to claim 1.

6. The aforementioned A is C １ - C ２０ alkyl of, or C ６ - C ２０ aryl of, and A exists alone or is a monovalent radical that is linked to R ａ through a hetero element of O, N, or S to form a ring, 【Chemical Formula 3】 (where q is an integer from 0 to 4) a divalent to hexavalent radical, * - NR １１ R １２ *, - NR １３ - *, 【Chemical Formula 4】 ,, * - NR １４ CSNR １５ - *, * - NR １６ CONR １７ - *, * - NR １８ L ２ NR １９ - *, * - NR ２０ CONR ２１ L ３ NR ２２ CONR ２３ - *, * - NR ２４ CONL ４ L ５ NCONR ２５ - *, 【Chemical Formula 5】 or 【Chemical Formula 6】 a radical in which the bonding site of is N (where R １１ ~R ２６ are each independently hydrogen, an alkyl group of C １ -C ２０ or an aryl group of C ６ -C ２０ ; L ２ ~L ６ is an alkylene of C １ -C ２０ an arylene of C ６ -C ２０ or R ３１ (OR ３２ ) ｒ ; where R ３１ and R ３２ are each independently an alkylene group of C １ -C ２０ ; r is an integer from 1 to 5; L ７ is a direct bond or (CH ２ ) ｓ NR ３３ NR ３４ ; where R ３３ and R ３４ are each independently hydrogen, an alkyl group of C １ -C ２０ or an aryl group of C ６ -C ２０ ; s is an integer from 1 to 5), or a radical in which the bonding site of *-O-* is O, or *-S-*, *-SS-*, 【Chemical Formula 7】 or 【Chemical Formula 8】 a radical in which the bonding site of is S, or 【Chemical Formula 9】 , 【Chemical Formula 10】 , 【Chemical Formula 11】 or 【Chemical Formula 12】 a radical in which the bonding site of is P (where R ２７ and R ２８ are each independently hydrogen, C １ -C ２０ alkyl group, C ６ -C ２０ aryl group, C １ -C ２０ alkoxy group, or C １ -C ２０ alkyl C １ -C ２０ alkoxy group), the silicon nitride film etching composition according to claim 1.

7. The A is *-(CH ２ ) ｐ R １０ [where p is an integer from 0 to 3, and R １０ is hydrogen (provided that p is not 0), halogen (provided that p is not 0), substituted or unsubstituted C １ -C ２０ alkyl group, substituted or unsubstituted C ６ -C ２０ aryl group, or substituted or unsubstituted C １ -C ２０ alkyl C １ -C ２０ alkoxy group], *-(CH=CH) ｍ N= (where m is an integer from 1 to 3, and is linked to R ａ through N to form a ring), 【Chemical Formula 13】 (where q is an integer from 0 to 4), *-NR １１ R １２ (where R １１ and R １２ are independently hydrogen, C １ -C ２０ alkyl group, or C ６ -C ２０ aryl group), *-NR １３ -* (where R １３ is hydrogen, C １ -C ２０ alkyl group, or C ６ -C ２０ aryl group), or [Chemical Formula 14] The etching composition for a silicon nitride film according to claim 1, which is

8. The A is *-CH ３ , [Chemical Formula 15] , *-CH=CHN=(wherein, it is linked to R ａ via N to form a ring), [Chemical Formula 16] , [Chemical Formula 17] , *-(CH ２ ) ２ -OCH ３ , or [Chemical Formula 18] The etching composition for a silicon nitride film according to claim 1, which is

9. The L is C １ -C １０ alkylene, the etching composition for a silicon nitride film according to claim 1.

10. The compound represented by the chemical formula 1 is a compound selected from the following structural formulas 1 to 8, the etching composition for a silicon nitride film according to claim 1. [Chemical Formula 19] …(1), [Chemical Formula 20] …(2), [Chemical Formula 21] …(3), [Chemical Formula 22] …(4), [Chemical Formula 23] …(5), 【Chemical formula 24】 …(6), 【Chemical formula 25】 …(7), 【Chemical formula 26】 …(8)

11. The etching composition for a silicon nitride film according to claim 1, wherein the silane compound containing one or more Si atoms is a silane compound represented by the following chemical formula 2. 【Chemical formula 27】 …[Chemical formula 2] In the chemical formula 2, R ５１ ~R ５４ are each independently hydrogen, a hydrocarbyl group of C １ -C ２０ or a heterohydrocarbyl group of C １ -C ２０ and R ５１ ~R ５４ are each present or are cyclic and linked to each other via two or more hetero elements.

12. The etching composition for a silicon nitride film according to claim 1, further comprising an ammonium salt.

13. The etching composition for a silicon nitride film according to any one of claims 1 to 12, wherein the compound represented by the chemical formula 1 is contained in an amount of 0.001 to 5% by weight based on the total weight of the etching composition.

14. The etching composition according to any one of claims 1 to 11, wherein the etching composition contains 70 to 90% by weight of phosphoric acid, 1 to 20% by weight of metaphosphoric acid, 0.001 to 5% by weight of the compound represented by the chemical formula 1, 0.005 to 1% by weight of a silane compound containing one or more Si atoms (excluding the compound represented by the chemical formula 1), and the balance is water.

15. An etching method for an insulating film using the etching composition for a silicon nitride film according to any one of claims 1 to 11.

16. A method for manufacturing a semiconductor device, including the method for etching an insulating film according to Claim 15.

17. A compound represented by the following Chemical Formula 1. 【Chemical Formula 28】 …[Chemical Formula 1] In the Chemical Formula 1, A is an n-valent radical, n is an integer from 1 to 3, L is a direct bond or a hydrocarbylene of C １ -C ３ and is a hydrocarbylene, Y is selected from O and S, X and Z are each independently selected from N, O, and S, R ａ and R ｂ are each independently a lone pair, hydrogen, a substituted or unsubstituted hydrocarbyl group, R ｃ is a substituted or unsubstituted hydrocarbyl group, Excluding the case where X, Y, and Z are simultaneously O.

18. R ｃ is C １ -C ２０ alkyl of, C ６ -C ２０ aryl of, or a functional group represented by the following formula, the compound according to Claim 17. 【Chemical Formula 29】 (Here, R ４ to R ９ are each independently hydrogen, a hydrocarbyl group or a non-hydrocarbyl group, L １ is a direct bond or a hydrocarbylene.)

19. The above R ４ to R ９ are all hydrogen, and L １ is a direct bond or C １ -C ５ The compound according to claim 18, wherein the alkylene is **Claim 20** wherein A is C １ -C ２０ alkyl or C ６ -C ２０ aryl, where A exists alone or is a monovalent radical linked to R ａ via a hetero element of O, N or S to form a ring, or **Chemical Formula 30** The compound according to claim 17, which is a trivalent radical of **Claim 21** wherein A is **Chemical Formula 31** (where p is an integer from 1 to 3, and R １０ is hydrogen, halogen, a substituted or unsubstituted C １ -C ２０ alkyl group, a substituted or unsubstituted C ６ -C ２０ aryl group, or a substituted or unsubstituted C １ -C ２０ alkyl C １ -C ２０ alkoxy group), **Chemical Formula 32** , or *-CH=CHN- (provided that it is linked to R ａ via N to form a ring), which is a monovalent radical of the compound according to claim 17. **Claim 22** A compound having any one of the structural formulas of the following formulas (2) to (5). **Chemical Formula 33** … (2), **Chemical Formula 34** … (3), **Chemical Formula 35** … (4), **Chemical Formula 36** … (5)

Images