METHOD FOR PRODUCING METAL FLUORIDE-CONTAINING ORGANIC POLYMER FILM, PATTERN FORMING METHOD, AND METHOD FOR PRODUCING SEMICONDUCTOR DEVICE

Abstract

To provide a method for preparing a metal fluoride-containing organic polymer film that is used as an etching mask, etc. and has high etching resistance as well as enabling an increase in etching rate.SOLUTION: In a method for preparing a metal fluoride-containing organic polymer film of the embodiment, an organic polymer film 5 is formed on a substrate 4, the organic polymer film 5 is exposed to an organic metallic compound 6 containing a first metal to impregnate the organic metallic compound containing the first metal in the organic polymer film 5X, and the organic polymer film 5X impregnated with the organic metallic compound containing the first metal is exposed to hydrogen fluoride 7 to produce fluoride of the first metal in the organic polymer film 5Y.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] An embodiment of the present invention relates to a method for producing a metal fluoride-containing organic polymer film, a patterning method, and a manufacturing method for a semiconductor device. [Background technology]

[0002] As semiconductor devices are becoming three-dimensional, there is an increasing demand for technology to form patterns with high aspect ratios. Mask patterns used in such processes are required to have resistance to etching gases because they are exposed to the etching gases for long periods of time. For example, when using an etching gas such as fluorocarbon gas, the mask pattern is required to have high etching resistance against fluorine radicals, fluorine-containing radicals, fluoride ions, and fluorine-containing ions, while the processed material is required to have a high etching rate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-023251 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a method for producing a metal fluoride-containing organic polymer film used for an etching mask or the like, a pattern formation method which has high etching resistance and enables an increased etching rate, and a method for manufacturing a semiconductor device. [Means for solving the problem]

[0005] A method for producing a metal fluoride-containing organic polymer film according to an embodiment includes forming an organic polymer film on a substrate, exposing the organic polymer film to an organometallic compound containing a first metal to impregnate the organic polymer film with the organometallic compound containing the first metal, and exposing the organic polymer film impregnated with the organometallic compound containing the first metal to hydrogen fluoride to produce a fluoride of the first metal in the organic polymer film. [Brief description of the drawings]

[0006] [Figure 1] 1A to 1C are diagrams illustrating steps of a pattern forming method according to an embodiment. [Diagram 2] 1A to 1C are diagrams illustrating a first example of a process for forming a metal fluoride-containing organic polymer film according to an embodiment. [Diagram 3] 5A to 5C are diagrams illustrating a second example of a process for forming a metal fluoride-containing organic polymer film according to an embodiment. [Figure 4] 6A to 6C are diagrams illustrating a third example of a process for forming a metal fluoride-containing organic polymer film according to an embodiment. [Diagram 5] 3 is a schematic diagram showing a shape when a substrate is etched using an organic polymer film on which a pattern according to an embodiment is formed as a mask. FIG. [Figure 6] 2A to 2C are diagrams illustrating steps of a method for manufacturing a semiconductor device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, the method for producing a metal fluoride-containing composite film, the method for forming a pattern, and the method for manufacturing a semiconductor device according to the embodiments will be described with reference to the drawings. In each embodiment, the same components are denoted by the same reference numerals, and the description thereof may be omitted. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each part, etc. may differ from the actual ones.

[0008] (Method of preparing metal fluoride-containing composite film and method of patterning) A method for producing a metal fluoride-containing organic polymer film and a method for forming a pattern according to an embodiment will be described with reference to Figs. 1 to 4. Fig. 1 is a cross-sectional view showing the steps of the pattern formation method according to an embodiment. In the pattern formation method shown in Fig. 1, as shown in Fig. 1(A), a film 2 to be processed formed on a substrate 1 is prepared, and an etching mask 3 is formed on the film 2 to be processed. The etching mask 3 is a metal fluoride-containing organic polymer film produced by applying the method for producing a metal fluoride-containing organic polymer film according to an embodiment. The film 2 to be processed is not particularly limited, and various functional films used in the manufacturing process of semiconductor devices may be used, for example.

[0009] A first example of the manufacturing process of the metal fluoride-containing organic polymer film as the etching mask 3 will be described in detail with reference to FIG. 2. First, as shown in FIG. 2(A), a substrate 1 having a film 2 to be processed is prepared as a base 4. Here, since it is assumed that the method is applied to a pattern forming method used in the manufacturing process of a semiconductor device, the substrate 1 having the film 2 to be processed is used as the base 4. However, when the metal fluoride-containing organic polymer film is applied to other uses, the base 4 is appropriately selected. The substrate 1 may be, for example, a semiconductor wafer such as a silicon substrate. As shown in FIG. 2(B), an organic polymer film 5 is formed on the base 4. The organic polymer film 5 is used to form an organic polymer film impregnated with a metal by exposing the organic polymer film 5 to an organometallic compound as a precursor of the metal to be impregnated. Here, the impregnation of the organic polymer film 5 with a metal by exposing the organic polymer film 5 to an organometallic compound is called metallization.

[0010] A spin on carbon (SOC) film or the like is used as the organic polymer film 5 to be metallized. The SOC film contains, for example, an ester group (-C(=O)-OR 1 ), amide group (-C(=O)-NR 1 R 2 ), imide group (-C(=O)-NR 1 -C(=O)-R 2 ) or the like. Here, R 1 and R 2are the same or different hydrogen groups (-H) or alkyl groups (-C n H 2n+1 The above-mentioned characteristic groups bond with organometallic compounds as metal precursors and promote the impregnation of metals into organic polymers. That is, the carbonyl group (-C(=O)-) and amino group (-NR 1 R 2 ), etc., and a structure is formed in which the organometallic compound is adsorbed to oxygen atoms and nitrogen atoms in the organic polymer film 5. Examples of organic polymers having the above-mentioned characteristic groups include polymethyl methacrylate (PMMA), poly(N-isopropylacrylamide) (PNIPAM), and polystyrene derivatives having the above-mentioned characteristic groups and aromatic rings in the side chains.

[0011] 2(C), the organic polymer film 5 is exposed to an organic metal compound 6 as a precursor of the metal M (first metal) to be impregnated, thereby impregnating the organic polymer film 5 with the organic metal compound 6. Here, the metal M used for metallization includes boron (B), aluminum (Al), lanthanum (La), thorium (Th), hafnium (Hf), titanium (Ti), zirconium (Zr), scandium (Sc), gadolinium (Gd), gallium (Ga), cerium (Ce), praseodymium (Pr), yttrium (Y), lithium (Li), silicon (Si), beryllium (Be), tantalum (Ta), vanadium (V), niobium (Nb), samarium (Sm), erbium (Er), terbium (Tb), neodymium (Nd), europium (Eu), holmium (Ho), strontium (Sr), proton (Pb), and the like. (Pu), dysprosium (Dy), calcium (Ca), chromium (Cr), germanium (Ge), cesium (Cs), indium (In), carbon (C), rubidium (Rb), potassium (K), sodium (Na), tin (Sn), molybdenum (Mo), magnesium (Mg), iron (Fe), manganese (Mn), nickel (Ni), antimony (Sb), cobalt (Co), neptunium (Np), copper (Cu), silver (Ag), gold (Au), platinum (Pt), arsenic (As), phosphorus (P), lutetium (Lu), bromine (Br), iodine (I), and ruthenium (Ru). Examples of organometallic compounds containing such a metal M include alkyl metals (M(C), such as trimethyl metal (M(CH3)3), and alkyl metals (M(C), such as trimethyl metal (M(CH3)3). n H 2n+1 ) x ) (wherein n is, for example, an integer of 1 or more and 4 or less, and x is an integer determined by the metal M, for example, an integer of 1 or more and 5 or less).

[0012] As described above, by exposing the organic polymer film 5 to an organometallic compound 6 containing a metal M, the organic polymer film 5 is impregnated with the organometallic compound 6 to form an organic polymer film 5X containing the organometallic compound 6. Next, as shown in FIG. 2(D), the organic polymer film 5X impregnated with the organometallic compound 6 such as MR3 is exposed to hydrogen fluoride (HF) 7. For exposure to HF7, either gaseous or liquid HF may be used, but gaseous HF is preferably used. M(CH3)3 and the like present in the organic polymer film 5X react with HF in the exposure atmosphere to produce metal fluoride (MF) according to the following formula (1): x ) is generated. M(CH3)3+3HF → MF3+3CH4…(1) In this way, by exposing the organic polymer film 5X to hydrogen fluoride (HF) 7, metal fluorides (MF x The metal fluoride present in the organic polymer film 5Y contributes to improving the etching resistance of the organic polymer film 5Y, so by using such an organic polymer film 5Y as the etching mask 3, the etching resistance of the etching mask 3 can be improved as described below in detail. x ) can be analyzed by, for example, X-ray photoelectron spectroscopy (XPS) or energy dispersive X-ray analysis (EDX) of a cross section of the organic polymer film 5Y.

[0013] The exposure of the organic polymer film 5 to the organometallic compound 6 is preferably carried out by, for example, maintaining the inside of the treatment chamber in which the organic polymer film 5 is placed in a vacuum state of 1 kPa or less, and then introducing the organometallic compound 6 into the treatment chamber under a pressure of 5 kPa or less to carry out an impregnation treatment. Then, it is preferable to introduce HF7 into the treatment chamber under a pressure of 5 kPa or less to carry out a fluorination treatment on the organic polymer film 5 that has been subjected to the exposure treatment of the organometallic compound 6. That is, HF gas is supplied into the treatment chamber. By carrying out the exposure treatment of the organometallic compound 6 and HF7 under such conditions, the impregnation of the organometallic compound 6 into the organic polymer film 5 and the fluorination of the organometallic compound 6 can be efficiently carried out. That is, the inside of the organic polymer film 5 can be impregnated with the organometallic compound 6, and the organometallic compound 6 can be efficiently fluorinated.

[0014] That is, in the post-treatment of M(CH3)3 and the like formed by metallizing the organic polymer film 5, M(CH3)3 and the like are oxidized to form a metal oxide (MO x ) is known to be formed in the organic polymer film 5. However, metal oxides (MO x As described below, metal fluorides (MF) have excellent resistance to oxygen-based gases, including oxygen radicals, used in RIE, but are not sufficiently resistant to CF gases. x ), as described in detail below, has excellent resistance to CF-based gases. For example, when aluminum (Al) is used as the metal M, the bond energy between Al and oxygen (O) is 501.9 kJ / mol, whereas the bond energy between Al and fluorine (F) is 675 kJ / mol. Therefore, Al is more stable as a fluoride than as an oxide, and Al tends to become a fluoride (AlF3). In addition, AlF3 has a high boiling point of 1276°C, and is resistant to chemical etching. Such metal fluorides (MF x By using the organic polymer film 5Y having fluorine-containing ... radicals present therein as the etching mask 3, it is possible to improve the resistance to etching by a CF-based gas containing fluorine ions and fluorine radicals.

[0015] Next, the metal M used in the organometallic compound 6 as a precursor will be described in detail. That is, in order to develop the resistance of the etching mask 3 to reactive ion etching (RIE), it is effective to impregnate an organic polymer (resin) with an organometallic compound and use the resin containing the metal compound as an etching mask in RIE. For processing silicon-based semiconductors, RIE is applied using CF-based gases such as CF4, CHF3, CH2F2, C4F6, and O2 as etchant gases. Under such circumstances, the material of the embodiment is used as an etching mask, and therefore is required to have high resistance to RIE using these gases.

[0016] The etching mechanism of RIE can be broken down into etching by chemical reaction (chemical etching), etching by physical sputtering (physical etching), and the deposition of a protective film, and the etching rate is determined by these factors. In general RIE, the element of chemical etching is strong, but in the high bias region, the element of physical etching cannot be ignored. When considering etching by chemical reaction, most metal compounds have high resistance to O2RIE, so simply impregnating a resin with a metal compound increases O2RIE resistance. In contrast, RIE resistance to CF-based gases is complex. First, in RIE using CF-based gases, it is necessary to increase resistance to F ions and F radicals, and for this to be possible, it is required that fluorides do not desorb from the system due to heat.

[0017] When CF-based RIE is performed, metal elements may combine with F elements to form fluorides. If the boiling point of this fluoride is lower than room temperature, it will volatilize. For example, the boiling point of silicon is -65°C, which is why it can be etched using CF-based gas RIE. Although not as bad as silicon, fluorides with low boiling points for common metals tend to undergo chemical reactions and are easily etched. For this reason, the boiling point of the fluoride is one of the selection criteria for metals to be impregnated into the resin, and metals with high fluoride boiling points are preferred. In addition, for metals with multiple fluorides, the fluoride with the lowest boiling point is used as the standard.

[0018] For example, CaF2, SrF2, SmF2, LaF3, CeF3, PrF3, EuF3, MgF2, YF3, HoF3, ErF3, YbF3, TmF3, BaF2, and MnF2 all have boiling points of 2000°C or higher. CdF2, NaF, LiF, ThF4, NiF2, ScF3, CuF2, KF, and ZnF2 all have boiling points of 1500°C or higher. CrF3, RbF, BeF2, FeF3, CoF3, PbF4, AIF3, CsF, RhF3, PdF2, InF3, and AgF all have boiling points of 1000°C or higher. GaF3, SnF4, HgF2, ZrF4, and BiF3 all have boiling points of 500°C or higher. By using these metal elements as the metal to be impregnated into the resin, the chemical reaction of the fluoride of the metal impregnated into the resin can be suppressed. Therefore, these metals are candidates for the metal M to be impregnated into the resin.

[0019] As mentioned above, RIE also includes a mode in which a high bias is applied to highly accelerate ions and etch using physical sputtering. From a molecular theory perspective, this is a phenomenon in which the bonds between fluorine and the fluorine-containing metal are broken and the metal is ejected by the ions and atoms bombarded by the sputtering. It is known that the etching (sputtering) speed at this time is the reciprocal of the bond energy between atoms. For this reason, it is preferable for the metal to be impregnated into the resin to have a high bond energy between the metal atom and the F atom.

[0020] For example, B, Al, La, Th, and Hf all have a bond energy with fluorine of 600 kJ / mol or more. Sc, Gd, Ga, Ce, Pr, Li, Si, Be, Ta, Sm, Er, Tb, Nd, Eu, Ho, Sr, Pu, Dy, Ca, Cr, Ge, Cs, In, and C all have a bond energy with fluorine of 500 kJ / mol or more. Rb, K, Na, Sn, Mo, Mg, Fe, Mn, Ni, Sb, Co, Np, Cu, As, P, Lu, and Ru all have a bond energy with fluorine of 400 kJ / mol or more. By impregnating the resin with these metal elements, physical sputtering of the metal impregnated in the resin can be suppressed. Therefore, these metals are listed as candidates for the metal M to be impregnated in the resin.

[0021] Examples of metal elements capable of suppressing both chemical reactions and physical sputtering include at least one metal selected from the group consisting of Li, Be, Na, Mg, Al, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Ga, Rb, Sr, In, Sn, Cs, La, Ce, Pr, Sm, Eu, Ho, Er, and Th.

[0022] Furthermore, the reactivity of the organometallic compound, which is a precursor for impregnating the resin with the metal, is also important because the metal element needs to remain in the resin in the form of a fluoride. In the manufacturing method of the embodiment, a metal element whose fluoride has a higher chemical stability than an oxide is preferred because it is easier to convert the metal oxide into a metal fluoride. Examples of metal elements whose bond energy with fluorine atoms is stronger than that with oxygen atoms include Li, Be, Na, Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Ga, Br, Rb, Sr, Ag, Cd, In, Sb, I, Cs, Eu, and Au.

[0023] In the ligand structure of the organometallic compound, which is a precursor, the element at the contact point on the ligand side that forms the metal and the ligand is often a carbon atom or a nitrogen atom. As will be described in detail later, in the manufacturing method of the embodiment, a method of forming a metal oxide once and then changing it to a fluoride is more effective. In this case, the organometallic compound, which is a precursor, needs to be oxidized. For this purpose, a metal that has a stronger bond with an oxygen atom than with a carbon atom or a nitrogen atom is preferable. When the element at the contact point on the ligand side is a carbon atom, it is preferable that the bond energy between an oxygen atom and a metal atom is higher than that between a carbon atom and a metal atom. Examples of such metal elements include Al, Sc, Ti, V, Fe, Ni, Ga, Ge, Y, Zr, Nb, Mo, In, La, Ce, Hf, Th, and U. When the element at the contact point on the ligand side is a nitrogen atom, it is preferable that the bond energy between an oxygen atom and a metal atom is higher than that between a nitrogen atom and a metal atom. Examples of such metal elements include Al, Sc, Ti, V, Cr, Y, Zr, I, Xe, La, Ce, Hf, W, Pt, Th, U, and Pu.

[0024] Among the candidates for metal M to be impregnated into the resin as described above, it is preferable to select metal M according to the properties required for the etching mask 3. In addition, when selecting metal M in the precursor, since the elements at the contact points on the ligand side do not need to react continuously or in parallel, it is sufficient that either carbon or nitrogen conditions are applied. The bond energy values ​​as described above are described in CRC handbook 100th, Edition, CRC press 2019, 9-73 Bond Dissociation Energy, etc.

[0025] MR present in the above organic polymer film 5X x When the organometallic compound 6 such as is exposed to hydrogen fluoride (HF) 7 to be fluorinated, if the exposure to HF is performed at a high temperature, the substrate below the organic polymer film 5X may be corroded. Therefore, it is preferable to expose the organic polymer film 5X to HF at a relatively low temperature, for example, in the temperature range of 0° C. to 200° C., and under a relatively high pressure, for example, in the pressure range of 60 Pa to 5000 Pa.

[0026] As described above, the metal M is added to the organic polymer film 5Y in the form of a metal fluoride (MF x ), the resistance of the organic polymer film 5Y to F ions and F radicals can be increased, and therefore the etching resistance by CF-based gas can be improved. Furthermore, as described above, RIE can be broken down into the elements of etching by chemical reaction and etching by physical sputtering. With regard to improving the etching resistance of the organic polymer film 5Y, it is particularly important to suppress etching of the organic polymer film 5Y by chemical reaction. In this regard, etching of the organic polymer film 5Y by chemical reaction can be suppressed by applying the above-mentioned conditions.

[0027] On the other hand, physical sputtering can be tolerated to a certain extent with respect to the etching resistance of the organic polymer film 5Y. Therefore, by allowing the fluorine to be removed from the organic polymer film 5Y by physical sputtering, fluorine can be supplied from the wall surface of a hole pattern formed in the organic polymer film 5Y, and etching of the processed film can be promoted. For example, in a hole pattern with a high aspect ratio, it is difficult for a fluorine-based etchant to reach the bottom of the hole, and etching of the processed film is difficult to proceed. In contrast, by supplying fluorine from the organic polymer film 5Y as the etching mask 3, it is possible to increase the etching efficiency of the processed film even when the processed film is etched through a hole pattern with a high aspect ratio.

[0028] Next, a second example of the process for producing a metal fluoride-containing organic polymer film as an etching mask will be described in detail with reference to Fig. 3. First, the same process as shown in Figs. 2(A), (B), and (C) is carried out to expose the organic polymer film 5 to an organometallic compound 6 as a precursor of metal M, as shown in Fig. 3(C), to form an organic polymer film 5X impregnated with the organometallic compound 6. Next, as shown in Fig. 3(D), the organic polymer film 5X impregnated with the organometallic compound 6 is exposed to an atmosphere containing an oxidizing substance 8 such as water vapor (H2O), ozone (O3), or oxygen plasma, thereby oxidizing M(CH3) present in the organic polymer film 5X. x In other words, by exposing the organic polymer film 5X to an oxidizing substance 8, M(CH3) is oxidized based on the following formula (2): x The organometallic compound 6 is oxidized. M(CH3)3+3H2O → M(OH)3+3CH4…(2)

[0029] Next, as shown in FIG. 3(E), the organic polymer film 5Z containing at least one of an oxide and a hydroxide of a metal M is exposed to hydrogen fluoride (HF) 7. By exposing the organic polymer film 5Z to HF 7 in this manner, a metal fluoride (MF x ) is generated. M(OH)3+3HF → MF3+3H2O …(3) The reactions according to the above formulas (2) and (3) have a higher reaction rate than the reaction according to the above formula (1). Therefore, by applying a two-step reaction of an oxidation reaction of the organometallic compound 6 and a fluorination reaction of the oxide, a metal fluoride (MF x In other words, the metal fluoride (MF) generated in the organic polymer film 5Y can be efficiently generated. x ) can be increased. This makes it possible to further improve the etching resistance of the organic polymer film 5Y. Furthermore, by applying the two-stage reaction, the reaction temperature can be selected from a wide range, making it possible to handle many organic polymers.

[0030] The exposure of the organic polymer film 5 to the organometallic compound 6 is preferably carried out under the same conditions as in the first example. Then, it is preferable to introduce an oxidizing agent 8 under a pressure of 5 kPa or less into the organic polymer film 5 that has been subjected to the exposure treatment of the organometallic compound 6, and carry out an oxidation treatment. Furthermore, it is preferable to introduce HF7 under a pressure of 5 kPa or less, and carry out a fluorination treatment, following the oxidation treatment of the organometallic compound 6. By carrying out the exposure treatment of the organometallic compound 6, the oxidizing agent 8, and HF7 under such conditions, it is possible to efficiently impregnate the organic polymer film 5 with the organometallic compound 6, oxidize the organometallic compound 6, and fluorinate the organometallic compound 6.

[0031] FIG. 5 shows a schematic diagram of etching the underlying Si substrate 1 with an etching gas of a mixture of C4F6, O2, and N2, using a pattern formed on an organic polymer film 3 as a mask. In Table 1, (A1) shows the etched depth of the Si substrate when etching is performed using a mask of polymer A that is not metallized, (A2) shows the etched depth of the Si substrate when etching is performed using a mask of polymer A that has been metallized and oxidized, and (A3) shows the etched depth of the Si substrate when etching is performed using a mask of polymer A that has been metallized, oxidized, and fluorinated. (B1) shows the etched depth of the Si substrate when etching is performed using a mask of polymer B that is not metallized, (B2) shows the etched depth of the Si substrate when etching is performed using a mask of polymer B that has been metallized and oxidized, and (B3) shows the etched depth of the Si substrate when etching is performed using a mask of polymer B that has been metallized, oxidized, and fluorinated.

[0032] As is clear from a comparison of (A1) and (A3) in Table 1, polymer A (A3) that has been subjected to metallization, oxidation and fluorination treatments has a deeper Si etching depth than polymer A (A1) that has not been metallized. A comparison of (A2) and (A3) shows that polymer A (A3) that has been subjected to metallization, oxidation and fluorination treatments has a deeper Si etching depth than polymer A (A2) that has been subjected to only metallization and oxidation treatments. The same can be seen from a comparison of (B1), (B2) and (B3).

[0033] [Table 1]

[0034] Next, a third example of the process for producing a metal fluoride-containing organic polymer film as an etching mask 3 will be described in detail with reference to FIG. 4. First, the same processes as those shown in FIGS. 2(A), (B), and (C) are carried out to expose the first organic polymer film 5 to an organometallic compound 6 as a precursor of metal M, as shown in FIG. 4(C), to form a first organic polymer film 5X impregnated with the organometallic compound 6. Next, as shown in FIG. 4(D), the first organic polymer film 5X impregnated with the organometallic compound 6 is exposed to hydrogen fluoride (HF) 7 to fluorinate the organometallic compound 6, thereby forming a metal fluoride (MF) 7. x The steps up to this point are carried out under the same conditions as in the first example.

[0035] Next, as shown in FIG. 4(E), the organometallic compound 6 is fluorinated to obtain a metal fluoride (MF xThe second organic polymer film 9 is formed on the first organic polymer film 5Y containing . The material for forming the second organic polymer film 9 may be the same organic polymer as that of the first organic polymer film 5, or may be a different organic polymer. By forming such a second organic polymer film 9 on the first organic polymer film 5Y, the second organic polymer film 9 can suppress the shoulder drop that occurs when the first organic polymer film 5Y is exposed to an etchant, that is, the etching of the corners on the open side of the first organic polymer film 5Y. In addition, when the second organic polymer film 9 is not mixed with the first organic polymer film 5Y and is not metallized, the laminated film of the first organic polymer film 5 and the second organic polymer film 9 may be subjected to an exposure treatment of the organometallic compound 6 and an exposure treatment of HF7.

[0036] In the pattern formation process shown in Fig. 1, the process of forming an etching mask 3 on a film 2 to be processed shown in Fig. 1 includes the above-mentioned organic polymer film coating process shown in Fig. 1(A) and then the process of forming a resist pattern 10 on the organic polymer film 3 shown in Fig. 1(B). The resist pattern 10 is formed by preparing a resist film on the organic polymer film 3 and patterning the resist film using lithography technology or imprint technology. In the imprint technology, resist is dropped on the organic polymer film 3, a template on which a fine pattern is formed is pressed against the resist film, and ultraviolet light is irradiated to harden the resist film, thereby forming the resist pattern 10.

[0037] Next, as shown in Fig. 1(C), the organic polymer film 3 is etched and patterned by dry etching such as reactive ion etching (RIE) or ion beam etching (IBE) using the resist pattern 10 as a mask. Fig. 1(C) shows the patterned organic polymer film 3. When the difference in etching rate between the resist film and the organic polymer film 3 with respect to the etching gas is small, it is preferable to insert SiO x The resist film and SiO XThe organic polymer film 3 may be patterned using the resist pattern 10 as a mask. Next, as shown in FIG. 1(D), the resist pattern 10 is removed. Thereafter, as shown in FIG. 1(E), an etching mask 3m containing a metal fluoride is obtained by applying a process of impregnating the organic polymer film 3 patterned as described above with an organometallic compound (M compound), a process of fluorinating the organic polymer film 3 impregnated with metal M, and, in some cases, an oxidation process and a fluorination process. Through these processes, a structure (pattern-formed body) 11 is obtained in which the etching mask 3m patterned on the processed film 2 is provided.

[0038] As shown in FIG. 1(F), the pattern forming body 11 is used for patterning the film 2 to be processed. Specifically, the film 2 to be processed is exposed to an etching gas through the patterned etching mask 3 and dry-etched. As a result, a patterned film 2 to be processed is obtained. For example, RIE or IBE is used for the dry etching. A gas containing fluorine (F) atoms is used as the etching gas. Fluorine (F) is, for example, fluorocarbon (C n F 2n+2 , C n F 2n , C n F 2n-2 It is preferable that the fluorine atoms (F) and oxygen atoms (O) are present in the etching gas as the fluorine atoms:n is a number between 1 and 6. It is preferable that the etching gas further contains oxygen (O2). In an etching gas containing fluorine atoms (F) and oxygen atoms (O), the ratio of the fluorine atoms to the oxygen atoms is preferably 1:1 (atom:atom), with the fluorine atoms being more abundant than the oxygen atoms. In addition, argon (Ar) or nitrogen (N2) may be added as necessary.

[0039] When forming a patterned processed film 2 using an etching gas containing fluorine (F) atoms as described above, it is desirable for the etching mask 3 to have high etching resistance against F radicals and the like. In response to such a demand, the organic polymer film 5Y containing metal fluoride formed by the method for producing a metal fluoride-containing organic polymer film of the embodiment has excellent etching resistance against F ions, F radicals, and the like as described above, and is therefore suitable as a mask for dry etching such as RIE. Therefore, it becomes possible to improve the accuracy of the pattern formation process shown in FIG. 1 and the subsequent etching process.

[0040] (Method of manufacturing a semiconductor device) Next, a method for manufacturing a semiconductor device according to an embodiment will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view showing the steps of the method for manufacturing a semiconductor device according to an embodiment. In the method for manufacturing a semiconductor device shown in FIG. 6, first, as shown in FIG. 6(A), a film to be processed 22 is formed on a semiconductor substrate 21. The film to be processed 22 is a laminated film in which, for example, silicon nitride films 23 and silicon oxide films 24 are alternately laminated. The laminated film 22 is used, for example, in the manufacture of a three-dimensional laminated nonvolatile memory device having a memory cell with a vertical transistor structure. An etching mask 3 is formed on the film to be processed 22 made of such a laminated film based on the pattern formation process of the embodiment described above. The etching mask 3 is the same as the etching mask used in the pattern formation method of the embodiment described above. The film to be processed 22 is not limited to a laminated film of the silicon nitride film 23 and the silicon oxide film 24, but may be a single film of a silicon oxide film or silicon nitride.

[0041] Next, as shown in FIG. 6(B), a resist pattern 10 is formed on the etching mask 3. The resist pattern 10 is formed by patterning the resist film formed on the etching mask 3 using lithography or imprinting, as in the pattern forming method of the embodiment. Next, as shown in FIG. 6(C), the etching mask 3 is etched and patterned by dry etching using the resist pattern 10 as a mask. As shown in FIG. 6(D), after removing the resist pattern 7, an impregnation process of an organometallic compound (M compound) is applied to the patterned organic polymer film 3, a fluorination process is applied to the organic polymer film 3 impregnated with the metal M, and in some cases, an oxidation process and a fluorination process are applied to obtain an etching mask 3m containing a metal fluoride. Through such a patterned etching mask 3m, the processed film 22 is exposed to an etching gas and dry-etched. By such dry etching, a patterned processed film 22 is obtained as shown in FIG. 6(E).

[0042] Dry etching is performed by RIE, IBE, or the like. A gas containing fluorine atoms (F) is used as the etching gas. The fluorine atoms (F) are, for example, fluorocarbons (C n F 2n+2 , C n F2, C n F 2n-2 It is preferable that the etching gas contains fluorine atoms (F) and oxygen atoms (O) in the form of fluorine atoms:n is a number between 1 and 6. It is preferable that the etching gas further contains oxygen gas (O2). In an etching gas containing fluorine atoms (F) and oxygen atoms (O), the ratio of fluorine atoms to oxygen atoms is preferably higher than that of 1:1 (atom:atom). By using such an etching gas containing fluorocarbon or the like, the film 22 to be processed, such as the laminated film described above, can be effectively etched.

[0043] As explained in the pattern forming method of the embodiment, by applying the etching mask 3 made by a specific process and material, high etching resistance can be obtained even when the processed film 22 is dry etched with an etching gas containing fluorocarbon or the like. Therefore, even when forming a pattern having holes with a high aspect ratio, such as the processed film 22 shown in FIG. 6, the pattern forming accuracy of the processed film 22 can be improved. This makes it possible to improve the forming accuracy and manufacturing yield of the semiconductor device. Note that in the semiconductor device manufacturing method of the embodiment, the processed film 22 is not limited to the laminated film as described above, and various films can be applied.

[0044] The patterned processed film 22 shown in FIG. 6(E) is applied to the fabrication of a memory cell array, for example, using a known method. For example, a hole pattern (memory hole) is formed in the laminated film by the above-mentioned process. In such a memory hole, a block insulating layer, a charge storage layer, a tunnel insulating layer, a channel layer, and a core layer are formed in that order. Furthermore, only the nitride film of the laminated film is removed through a slit formed separately from the memory hole, and a conductive film is embedded in the resulting space. As a result, a laminated film in which insulating films (oxide films) and conductive films are alternately stacked is obtained, and a memory cell structure with a vertical transistor structure can be formed. The conductive film in the laminated film can be made to function as a word line.

[0045] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0046] 1, 21...substrate, 2, 22...film to be processed, 3...etching mask, 4...base, 5...polymer film, 5X...metal-containing organic polymer film, 5Y...metal fluoride-containing organic polymer film, 5Z...metal oxide-containing organic polymer film, 6...organometallic compound, 7...hydrogen fluoride, 8...oxide material, 9...second organic polymer film, 11...pattern-forming body, 23...silicon nitride film, 24...silicon oxide film.

Claims

1. forming an organic polymer film on a substrate; exposing the organic polymer film to an organometallic compound containing a first metal, thereby impregnating the organic polymer film with the organometallic compound containing the first metal; exposing the organic polymer film impregnated with the organometallic compound containing the first metal to hydrogen fluoride to generate a fluoride of the first metal within the organic polymer film; The first metal includes at least one selected from the group consisting of lithium, beryllium, sodium, magnesium, aluminum, potassium, calcium, scandium, chromium, manganese, iron, cobalt, nickel, copper, gallium, rubidium, strontium, indium, tin, cesium, lanthanum, cerium, praseodymium, samarium, europium, holmium, erbium, and thorium; Method for preparing metal fluoride-containing organic polymer films.

2. 2. The method for producing a metal fluoride-containing organic polymer film according to claim 1, wherein the organic polymer film is maintained in a vacuum atmosphere of 1 kPa or less, and then exposed to an organometallic compound containing the first metal under a pressure of 5 kPa or less, and the organic polymer film impregnated with the organometallic compound containing the first metal is subsequently exposed to the hydrogen fluoride under a pressure of 5 kPa or less.

3. 3. The method for producing a metal fluoride-containing organic polymer film according to claim 1 or 2, comprising exposing the organic polymer film impregnated with an organometallic compound containing the first metal to water vapor, ozone, or oxygen plasma to generate at least one selected from an oxide and a hydroxide of the first metal in the organic polymer film, and then exposing the organic polymer film containing the at least one selected from an oxide and a hydroxide of the first metal to hydrogen fluoride.

4. 4. The method for producing a metal fluoride-containing organic polymer film according to claim 1, wherein the organometallic compound is an alkyl metal.

5. 5. The method for producing a metal fluoride-containing organic polymer film according to claim 1, further comprising the step of forming a second organic polymer film on the organic polymer film containing the fluoride of the first metal.

Images