Surface protector of thin film and deposition method of thin film using the same

Abstract

The present invention relates to high-purity molybdenum dichloride and a method for manufacturing the same, wherein the molybdenum dichloride is characterized by having a silicon (Si) content of 400 ppm by weight or less among impurities, and high-purity molybdenum dichloride can be obtained by manufacturing including a sublimation purification process.

Description

Technology Field

[0001] The present invention relates to a compound for inhibiting thin film growth and a method for forming a thin film using the same. More specifically, the invention relates to a compound for inhibiting thin film growth suitable for a high-temperature deposition process and a method for forming a thin film using the same, which has characteristics suitable for a high-temperature deposition process and can improve step coverage and reduce process by-products by controlling the thin film deposition thickness through inhibition of thin film growth. Background Technology

[0003] Recently, Atomic Layer Deposition (ALD) has been widely applied as a method for forming thin films of metals, metal oxides, and metal nitrides. While the ALD process offers advantages such as improved step coverage and reduced process byproducts compared to conventional Chemical Vapor Deposition (CVD), processes capable of manufacturing high-quality thin films are being developed as semiconductor manufacturing becomes more miniaturized.

[0004] For this improved process, when performing the thin film formation process, a compound capable of inhibiting thin film growth is used to react with the surface to form a deposition inhibition layer in the deposition avoidance region. Through surface control, it is possible to control the thin film thickness and the thin film deposition location, thereby enabling the production of high-quality thin films.

[0005] While fluorine gas is currently used as a compound to inhibit thin film growth for silicon-containing films, new compounds capable of handling various thin film formation processes are also being developed.

[0006] For example, Korean Published Patent Application No. 10-2022-0136073 uses acetic acid compounds such as methyl acetate, ethyl acetate, methyl propionate, and ethyl propionate to form a thin film growth inhibition layer. Additionally, Korean Published Patent Application No. 10-2022-0136072 uses a metal alkoxide capable of coordinating with the deposited body, and Korean Published Patent Application No. 10-2021-0046235, Korean Published Patent Application No. 10-2021-0027069, etc. use halogen compounds to form a thin film growth inhibition layer.

[0007] Although high-quality thin films can be formed via the ALD process by applying such thin film growth inhibitory compounds, there is a problem that their use is limited in high-temperature deposition processes due to the difficulty of achieving stable bonding between the deposited material and the compound. Prior art literature

[0009] Republic of Korea Published Patent Application No. 10-2022-0136073 Republic of Korea Published Patent Application No. 10-2022-0136072 Republic of Korea Published Patent Application No. 10-2021-0046235 Republic of Korea Published Patent Application No. 10-2021-0027069 The problem to be solved

[0010] The present invention has been devised in consideration of the prior art described above, and aims to provide a compound for inhibiting thin film growth and a method for forming a thin film using the same, which enables the formation of a high-quality thin film by forming a thin film growth inhibition layer in a high-temperature thin film formation process to control the growth thickness of the thin film. means of solving the problem

[0012] The thin film growth inhibitory compound of the present invention for achieving the above-mentioned purpose is a compound that inhibits thin film growth by binding to a deposit formed on the surface of a substrate in a process of forming a thin film by introducing a metal-containing precursor and a reactive gas onto the surface of a substrate, and is characterized by having a decomposition temperature of 300°C or higher and being a coordination-bonding type compound that coordinates with the deposit or a reactive type compound that reacts with the deposit.

[0013] At this time, the compound for inhibiting the growth of a coordinate-bonded thin film may be a compound represented by Chemical Formula 1 or 2.

[0015] [Chemical Formula 1]

[0016]

[0017] [Chemical Formula 2]

[0018]

[0020] In the above chemical formulas 1 and 2, R1 to R2 are each independently a straight-chain, branched, or cyclic hydrocarbon of C1 to C6, R3 to R5 are each independently a hydrogen atom, a straight-chain, branched, or cyclic hydrocarbon of C1 to C3, and in chemical formula 2, n and m are each independently any one integer from 1 to 3.

[0021] In addition, the above-mentioned reactive thin film growth inhibitory compound may be a compound represented by chemical formula 3, 4, or 5.

[0023] [Chemical Formula 3]

[0024]

[0026] [Chemical Formula 4]

[0027]

[0029] [Chemical Formula 5]

[0030]

[0032] In the above chemical formula 3, R1 to R2 are each independently a straight-chain, branched, or cyclic hydrocarbon of C1 to C3, R3 to R4 are each independently a hydrogen atom, a straight-chain, branched, or cyclic hydrocarbon of C1 to C3, and n is any one integer from 1 to 3, and in the above chemical formulas 4 and 5, R1 to R2 are each independently a straight-chain, branched, or cyclic hydrocarbon of C1 to C3.

[0033] In addition, the thin film forming method of the present invention is characterized by comprising the steps of: positioning a substrate in a chamber; supplying a compound for inhibiting thin film growth into the chamber; purging the interior of the chamber and supplying a metal precursor; and purging the interior of the chamber and supplying a reactive gas.

[0034] In addition, the ALD window of the above thin film formation method may be 350 to 400°C. Effects of the invention

[0036] The thin film growth inhibitory compound according to the present invention can be applied to a high-temperature thin film formation process and forms a thin film growth inhibitory layer to control the growth thickness of the thin film and exhibits the effect of forming a high-quality thin film. Brief explanation of the drawing

[0038] Figure 1 is a conceptual diagram illustrating the process in which a coordination-type thin film growth inhibitor compound (a) and a reactive-type thin film growth inhibitor compound (b) react with a deposit on a substrate surface. Figure 2 shows the results of measuring the change in HfO2 thin film deposition thickness according to the change in feeding time of C-2-4 at 350°C (a), 370°C (b), and 400°C (c) when depositing an HfO2 thin film using CpHf. Figure 3 shows the results of measuring the change in HfO2 thin film deposition thickness according to the change in purge time applied to C-2-4 at 350°C (a), 370°C (b), and 400°C (c) when depositing an HfO2 thin film using CpHf. Figure 4 shows the XPS analysis results of HfO2 thin films deposited by applying C-2-4 at 350°C (a) and 400°C (b) conditions when depositing HfO2 thin films using CpHf. Figure 5 shows the results of measuring the change in HfO2 thin film deposition thickness according to the change in feeding time when R-1-2 is applied at 350°C (a), 370°C (b), and 400°C (c) during HfO2 thin film deposition using CpHf. Figure 6 shows the XPS analysis results of HfO2 thin films deposited by applying R-1-2 at 350°C (a) and 400°C (b) conditions when depositing HfO2 thin films using CpHf. Figure 7 shows the XPS analysis results of HfO2 thin films deposited by applying R-1-1 at 350°C (a) and 400°C (b) conditions when depositing HfO2 thin films using CpHf. Figure 8 shows the results of measuring the change in Al2O3 thin film deposition thickness when C-2-4, R-1-1, and R-1-2 are applied at 350°C and 0.02 Torr conditions during Al2O3 thin film deposition using TMA. Figure 9 shows the results of measuring the change in Al2O3 thin film deposition thickness according to the change in feeding time when R-1-2 was applied at 350°C during Al2O3 thin film deposition using TMA. Figure 10 shows the XPS analysis results of HfO2 thin films deposited by applying C-2-7 at 350°C (a) and 400°C (b) when depositing HfO2 thin films using CpHf. Specific details for implementing the invention

[0039] The present invention will be described in more detail below. Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0041] A general thin film formation process involves introducing a metal-containing precursor and a reactive gas onto the surface of a substrate to form a thin film, wherein the metal-containing precursor is adsorbed onto the substrate and then reacts with the reactive gas to form a thin film on the substrate. In this process, a deposit formed by the metal-containing precursor or a deposit formed by the reaction between the metal adsorbed on the surface and the reactive gas is formed on the substrate. The thin film growth inhibiting compound of the present invention is a compound that inhibits thin film growth by binding to the deposit formed on the surface of the substrate during the thin film formation process. The thin film growth inhibiting compound of the present invention has a decomposition temperature of 300°C or higher and can be used in high-temperature thin film formation processes.

[0042] The above-mentioned compound for inhibiting thin film growth may be a coordination-bonding type compound that coordinates with the deposited body or a reactive type compound that reacts with the deposited body. Referring to FIG. 1, the compound for inhibiting thin film growth is described as follows: the coordination-bonding type compound forms a coordination bond with a metal adsorbed on the substrate as shown in FIG. 1(a) to form a thin film growth inhibiting layer, and due to the size of the compound for inhibiting thin film growth, it can exhibit a sufficient blocking effect. In addition, the reactive compound for inhibiting thin film growth forms a bond by reacting with an oxygen atom bonded to a metal adsorbed on the substrate as shown in FIG. 1(b). For example, such an oxygen-compound bond can be formed by reacting with the hydroxyl group of a metal hydroxide adsorbed on the surface of the substrate. Although this may reduce the blocking effect under a high-temperature ozone (O3) atmosphere, it can be effectively applied in general high-temperature processes.

[0043] The above-mentioned compound for inhibiting the growth of a coordinate-bonded thin film may be a compound represented by Chemical Formula 1 or 2.

[0045] [Chemical Formula 1]

[0046]

[0047] [Chemical Formula 2]

[0048]

[0050] In the above chemical formulas 1 and 2, R1 to R2 are each independently a straight-chain, branched, or cyclic hydrocarbon of C1 to C6, R3 to R5 are each independently a hydrogen atom, a straight-chain, branched, or cyclic hydrocarbon of C1 to C3, and in chemical formula 2, n and m are each independently any one integer from 1 to 3.

[0051] In addition, the above-mentioned reactive thin film growth inhibitory compound may be a compound represented by chemical formula 3, 4, or 5.

[0052] The above compound has a chemical structure containing oxygen atoms and can form a bonded state by forming a coordination bond between the oxygen atoms and metal atoms adsorbed on the substrate surface.

[0053] Examples of compounds represented by the above chemical formulas 1 and 2 include compounds such as those in Table 1.

[0055] number compound MW(g / mol) bp(℃) C-2-3 Dimethoxymethane (CH3OCH2OCH3) 76.09 42 C-2-4 Ethylene glycol diethyl ether (CH3CH2OCH2CH2OCH2CH3) 118.17 121 C-2-5 1,2-Dimethoxyethane (CH3OCH2CH2OCH3) 90.12 85 C-2-7 t-butylmethyl ether ((CH3)3COCH3) 88.15 55.2 C-2-8 Diethylene glycol dimethyl ether (CH3OCH2CH2OCH2CH2OCH3) 134.17 162

[0057] The compounds in Table 1 have a boiling point (bp) lower than the deposition temperature, so they can be vaporized and supplied onto the substrate, and can form coordination bonds with the deposited material, thus forming an effective thin film growth inhibition layer.

[0058] In addition, the above-mentioned reactive thin film growth inhibitory compound may be a compound represented by chemical formula 3, 4, or 5.

[0060] [Chemical Formula 3]

[0061]

[0063] [Chemical Formula 4]

[0064]

[0066] [Chemical Formula 5]

[0067]

[0069] In the above chemical formula 3, R1 to R2 are each independently a straight-chain, branched, or cyclic hydrocarbon of C1 to C3, R3 to R4 are each independently a hydrogen atom, a straight-chain, branched, or cyclic hydrocarbon of C1 to C3, and n is any one integer from 1 to 3, and in the above chemical formulas 4 and 5, R1 to R2 are each independently a straight-chain, branched, or cyclic hydrocarbon of C1 to C3.

[0070] Examples of compounds represented by the above chemical formulas 3 to 5 include compounds such as those shown in Table 2.

[0072] number compound MW(g / mol) bp(℃) R-1-1 3,4-Dihydropyran 84.12 86 R-1-2 Dimethyl carbonate (CH3OCOOCH3) 90.08 90 R-1-3 t-butyl acetate((CH3)3CO(CO)CH3) 116.16 97

[0074] The compounds in Table 2 can also be vaporized and supplied onto the substrate, and can form a chemical bond with the deposited material, thereby forming an effective thin film growth inhibition layer.

[0075] The method for forming a thin film by applying the above-described thin film growth inhibitory compound may include the steps of positioning a substrate in a chamber, supplying the thin film growth inhibitory compound into the chamber, purging the inside of the chamber and supplying a metal precursor, and purging the inside of the chamber and supplying a reactive gas.

[0076] In other words, a thin film growth inhibitor compound can be adsorbed first to protect the substrate surface before the metal-containing precursor for thin film formation is adsorbed onto the substrate surface. In this case, process by-products generated by reacting with reactive gases during thin film formation are removed along with the thin film growth inhibitor compound, thereby preventing corrosion or degradation of the substrate and appropriately lowering the thin film growth rate per cycle, which improves step coverage and the uniformity of thin film thickness. Furthermore, to deposit a thin film of a desired thickness, the unit cycle of the thin film formation process can be appropriately selected and performed, taking into account the thin film growth rate per cycle corresponding to the reduced deposition rate.

[0077] The thin film produced through the above-described process is manufactured through a high-temperature process of 300°C or higher, preferably 350°C or higher, and in the ALD process to which the thin film formation method of the present invention is applied, the process can be performed under conditions where the ALD window is 300 to 450°C, preferably 300 to 450°C.

[0078] As a substrate for the above thin film formation process, silicon-containing thin films such as glass, silicon, silicon oxide, and silicon nitride films, and metal-containing thin films such as rapid oxide films and metal nitride films may be used, and a semiconductor substrate of silicon or silicon oxide may be used. In addition, as the metal forming the thin film, a Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, or Group 8 metal may be applied.

[0079] The effects of applying the thin film growth inhibitory compound of the present invention to a process are explained below through examples.

[0081] [Gong Jeong-ye 1]

[0082] A thin film formation process was performed using ethylene glycol diethyl ether (C-2-4) as a compound for inhibiting thin film growth. Cyclopentadienyl hafnium (CpHf) was used as a precursor for thin film formation, and ozone was used as a reactive gas. The deposition temperature was 300°C or higher, and a hafnium oxide thin film was formed on a silicon oxide (SiO2) substrate, with a 50-cycle process performed.

[0083] As a result of measuring the thickness of the hafnium oxide thin film on the substrate using ellipsometry, the thin film thickness was 43 Å at 350°C when no thin film growth inhibitor compound was supplied, as shown in Fig. 2(a). A thin film formation process was performed using the C-2-4 thin film growth inhibitor compound at 350°C, 370°C, and 400°C for supply times of 1 second, 3 seconds, and 5 seconds, respectively, and the thickness stabilized with a GPC reduction rate of approximately 39% starting from 1 second (Fig. 2).

[0084] In addition, a thin film formation process was performed using C-2-4 thin film growth inhibitor compounds at 350°C, 370°C, and 400°C, respectively, with purging times of 30 seconds, 60 seconds, and 90 seconds, and the thin film growth inhibitor compound stabilized with a GPC reduction rate of approximately 41% starting from a purging time of 30 seconds (Fig. 3).

[0085] In addition, to confirm the impurity composition of thin films formed using cyclopentadienyl hafnium (CpHf) as a precursor for thin film formation, ozone as a reactive gas, and ethylene glycol diethyl ether (C-2-4) as a compound for inhibiting thin film growth, compositional analysis of the experimental thin films was performed using XPS under process conditions of 350°C and 400°C. As a result of the analysis, as shown in Figure 4, hafnium dioxide was formed in the thin films at 350°C and 400°C, and nitrogen and carbon elements were not detected.

[0087] [Gong Jeong-ye 2]

[0088] A thin film formation process was performed using dimethyl carbonate (R-1-2) as a compound for inhibiting thin film growth. Cyclopentadienyl hafnium (CpHf) was used as a precursor for thin film formation, and ozone was used as a reactive gas. The deposition temperature was 300°C or higher, and a hafnium oxide thin film was formed on a silicon oxide (SiO2) substrate, with a 50-cycle process.

[0089] As a result of measuring the thickness of the hafnium oxide thin film on the substrate using ellipsometry, the film thickness was 44 Å at 350°C when no thin film growth inhibitor compound was supplied, as shown in Fig. 5(a). A thin film formation process was performed using the R-1-2 thin film growth inhibitor compound at 350°C, 370°C, and 400°C for supply times of 1 second, 3 seconds, 5 seconds, and 10 seconds, respectively, and a GPC reduction rate of approximately 63% was confirmed starting from 1 second at process temperatures of 350°C, 370°C, and 400°C (Fig. 5).

[0090] In addition, to confirm the impurity composition of thin films formed using cyclopentadienyl hafnium (CpHf) as a precursor for thin film formation, ozone as a reactive gas, and dimethyl carbonate (R-1-2) as a compound for inhibiting thin film growth, compositional analysis of the experimental thin films was performed using XPS under process conditions of 350°C and 400°C. As shown in Figure 6, hafnium dioxide was formed in the thin films at 350°C and 400°C, and nitrogen and carbon elements were not detected.

[0092] [Gong Jeong-ye 3]

[0093] A thin film formation process was performed using 2,3-dihydropyran (R-1-1) as a compound for inhibiting thin film growth. Cyclopentadienyl hafnium (CpHf) was used as a precursor for thin film formation, and ozone was used as a reactive gas. The deposition temperature was 300°C or higher, and a hafnium oxide thin film was formed on a silicon oxide (SiO2) substrate, with a 50-cycle process.

[0094] To confirm the impurity composition of thin films formed using cyclopentadienyl hafnium (CpHf) as a precursor for thin film formation, ozone as a reactive gas, and 2,3-dihydropyran (R-1-1) as a compound for inhibiting thin film growth, compositional analysis was performed on the experimental thin films using XPS under process conditions of 350°C and 400°C. As shown in Figure 7, hafnium dioxide was formed in the thin films at 350°C and 400°C, and nitrogen and carbon elements were not detected.

[0096] [Gong Jeong-ye 4]

[0097] Deposition experiments were conducted using ethylene glycol diethyl ether (C-2-4), dimethyl carbonate (R-1-2), and 2,3-dihydropyran (R-1-1) as compounds for inhibiting thin film growth, and trimethylaluminum (TMA) as a precursor for forming thin films. Growth inhibition according to each compound for inhibiting thin film growth was confirmed at a process temperature of 350°C as shown in Figure 8. In forming an Al2O3 thin film, a reduction rate of approximately 45% was confirmed for dimethyl carbonate (R-1-2) as a compound for inhibiting growth.

[0098] As a result of performing a thin film formation process with the R-1-2 thin film growth inhibitor compound at a process temperature of 350°C as shown in Fig. 9 and supply times of the thin film growth inhibitor compound as shown in Fig. 3 at 1 second, 3 seconds, 5 seconds, and 10 seconds, the GPC was stabilized at a reduction rate of about 45% starting from 1 second.

[0100] [Gong Jeong-ye 5]

[0101] A thin film formation process was performed using methyl tertiary butyl ether (C-2-7) as a compound for inhibiting thin film growth. Cyclopentadienyl hafnium (CpHf) was used as a precursor for thin film formation, and ozone was used as a reactive gas. A hafnium oxide thin film was formed on a silicon oxide (SiO2) substrate at temperatures of 350°C and 400°C, and a 50-cycle process was performed.

[0102] To confirm the impurity composition of thin films formed using cyclopentadienyl hafnium (CpHf) as a precursor for thin film formation, ozone as a reactive gas, and methyl tertiary butyl ether (C-2-7) as a compound for inhibiting thin film growth, compositional analysis of the experimental thin films was performed using XPS under process conditions of 350°C and 400°C. As shown in Figure 10, hafnium dioxide was formed in the thin films at 350°C and 400°C, and nitrogen and carbon elements were not detected.

[0103] From these results, it was confirmed that the thin film growth inhibitory compound of the present invention has characteristics suitable for high-temperature deposition processes and is suitable for processes that can improve step coverage and reduce process by-products by controlling the thin film deposition thickness through thin film growth inhibition, thereby enabling the formation of high-quality thin films.

[0105] Although the present invention has been described with reference to preferred embodiments as described above, it is not limited to the above embodiments and various modifications and changes are possible by those skilled in the art within the scope of the invention without departing from the spirit of the invention. Such modifications and changes should be deemed to fall within the scope of the present invention and the appended claims.

Claims

Claim 1 A thin film growth inhibiting compound that inhibits thin film growth by binding with a deposit formed on the surface of a substrate in a process of forming a thin film by introducing a metal-containing precursor and a reactive gas onto the surface of a substrate, wherein the thin film growth inhibiting compound has a decomposition temperature of 300°C or higher, and wherein the thin film growth inhibiting compound is a coordinate bonding type that coordinates with the deposit or a reactive type that reacts with the deposit, and is a compound represented by any one of Chemical Formulas 2 to 4. [Chemical Formula 2] In the above Chemical Formula 2, R1 to R2 are each independently a C1 to C6 straight-chain, branched, or cyclic hydrocarbon, R3 to R6 are each independently a C1 to C3 straight-chain, branched, or cyclic hydrocarbon, and n and m are each independently any one integer from 1 to 3. [Chemical Formula 3] [Chemical Formula 4] In the above chemical formula 3, R1 to R2 are each independently a C1 to C3 straight-chain, branched, or cyclic hydrocarbon, R3 to R4 are each independently a hydrogen atom, a C1 to C3 straight-chain, branched, or cyclic hydrocarbon, and n is any one integer from 1 to 3, and in the above chemical formula 4, R1 to R2 are each independently a C1 to C3 straight-chain, branched, or cyclic hydrocarbon. Claim 2 delete Claim 3 delete Claim 4 A method for forming a thin film, characterized by comprising: a step of positioning a substrate in a chamber; a step of supplying a compound for inhibiting thin film growth according to claim 1 into the chamber; a step of purging the inside of the chamber and supplying a metal precursor; and a step of purging the inside of the chamber and supplying a reactive gas. Claim 5 A thin film forming method according to claim 4, characterized in that the ALD window of the thin film forming method is 350 to 400℃.

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