Etching method and etching apparatus

Abstract

To provide an etching method capable of etching a film containing Si and O with high selectivity, and an etching device.SOLUTION: An etching method for selectively etching a material containing Si and O includes the steps of: providing a substrate including the material containing Si and O inside of a chamber; repeating a first period which is started first and in which a basic gas is supplied and a second period which is started next and in which a fluorine-containing gas is supplied, and preventing at least a part of the second period from overlapping the first period; and heating and removing a reaction product generated by supplying the basic gas and the fluorine-containing gas.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an etching method and an etching apparatus. [Background technology]

[0002] Recently, a technique called chemical oxide removal (COR) has become known in the semiconductor device manufacturing process, which involves chemical etching without generating plasma in a chamber. One known COR technique uses hydrogen fluoride (HF) gas, a fluorine-containing gas, and ammonia (NH) gas, a basic gas, on the silicon oxide (SiO) film present on the surface of a semiconductor wafer substrate (see, for example, Patent Documents 1 and 2). In this technique, HF gas and NH react with the silicon oxide film to generate ammonium silicofluoride ((NH)SiF; AFS), which is then sublimated by heating, thereby etching the silicon oxide film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-39185 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-160000 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides an etching method and an etching apparatus capable of etching a film containing Si and O with high selectivity. [Means for solving the problem]

[0005] An etching method according to an embodiment of the present disclosure is an etching method for selectively etching a material containing Si and O, the method comprising the steps of: Includes etching targets and non-etching targetsThe method includes the steps of: placing a substrate in a chamber; repeating a first period in which a basic gas is supplied first; and a second period in which a fluorine-containing gas is supplied second; and making at least a part of the second period not overlap with the first period; and removing by heating reaction products produced by the supply of the basic gas and the fluorine-containing gas. The etching target is a material containing Si and O, and the non-etching target is a material containing Si and N and / or C, and the material containing Si and O is SiO 2 , SiON, SiOCN, SiOC, and the material containing Si and N and / or C is selected from SiN, SiOCN, SiOC, SiCN, SiC (provided that the material containing Si and O is SiO 2 and the material containing Si and N and / or C is SiN), when the material containing Si and O to be etched and the material containing Si and N and / or C to be not etched are both SiOCN or both SiOC, the C concentration of the SiOCN or SiOC to be etched is relatively low, and the C concentration of the SiOCN or SiOC to be not etched is relatively high. [Effects of the Invention]

[0006] According to the present disclosure, an etching method and an etching apparatus are provided that are capable of etching a film containing Si and O with high selectivity. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing an example of an etching apparatus for carrying out an etching method according to an embodiment. [Figure 2] 1 is a flowchart illustrating an etching method according to an embodiment. [Figure 3] 1A and 1B are diagrams illustrating an example of the structure of a substrate to which an etching method according to an embodiment is applied; [Figure 4] FIG. 10 is a diagram illustrating a typical example of step 3. [Figure 5] FIG. 10 is a diagram illustrating another example of step 3. [Figure 6] FIG. 10 is a diagram illustrating yet another example of step 3. [Figure 7A] 1A to 1C are diagrams for explaining the mechanism of an etching method according to an embodiment. [Figure 7B] 1A to 1C are diagrams for explaining the mechanism of an etching method according to an embodiment. [Figure 7C] 1A to 1C are diagrams for explaining the mechanism of an etching method according to an embodiment. [Figure 8A] FIG. 1 is a diagram for explaining the mechanism of a conventional etching method. [Figure 8B]FIG. 1 is a diagram for explaining the mechanism of a conventional etching method. [Figure 8C] 1 is a diagram for explaining the mechanism of a conventional etching method, and FIG. 2 is a schematic diagram showing the state after the heat treatment in the second step of removing etching residues has been performed. [Figure 9] 10A and 10B are diagrams illustrating another example of the structure of a substrate to which an etching method according to an embodiment is applied. [Figure 10] FIG. 1 is a diagram showing pattern 1 (conventional example) used in an experimental example. [Figure 11] FIG. 10 is a diagram showing pattern 2 (HF pulse) used in the experimental example. [Figure 12] FIG. 10 is a diagram showing pattern 3 (synchro pulse) used in the experimental example. [Figure 13] FIG. 10 is a diagram showing pattern 4 (embodiment) used in the experimental example. [Figure 14] FIG. 10 is a diagram showing the etching amounts of patterns 1 to 4 in an experimental example. [Figure 15] FIG. 10 is a diagram showing SiN shoulder loss in patterns 1 to 4 in an experimental example. [Figure 16] FIG. 10 is a diagram showing the selectivity of SiO 2 films to SiN in patterns 1 to 4 in an experimental example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] <Etching equipment> FIG. 1 is a cross-sectional view showing an example of an etching apparatus for carrying out an etching method according to one embodiment. The etching apparatus shown in FIG. 1 etches a material containing silicon (Si) and oxygen (O) present on, for example, the surface of a substrate. A representative example of a material containing Si and O is SiO2, but it may also be SiON, SiOCN, or SiOC. The material containing Si and O is typically a film.

[0010] 1, the etching apparatus 1 includes a sealed chamber 10, and a mounting table 12 is provided inside the chamber 10 on which a substrate W is placed in a substantially horizontal position. The substrate W may be, for example, a semiconductor wafer such as a Si wafer, but is not limited to this.

[0011] The etching apparatus 1 also includes a gas supply mechanism 13 that supplies a processing gas to the chamber 10, and an exhaust mechanism 14 that exhausts the inside of the chamber 10.

[0012] The chamber 10 is composed of a chamber body 21 and a lid 22. The chamber body 21 has a substantially cylindrical sidewall 21a and a bottom 21b, and an opening at the top that is closed by the lid 22, which has a recessed portion therein. The sidewall 21a and the lid 22 are sealed by a sealing member (not shown), ensuring airtightness within the chamber 10.

[0013] A shower head 26, which is a gas introduction member, is fitted inside the lid 22 so as to face the mounting table 12. The shower head 26 has a cylindrical main body 31 having a side wall and an upper wall, and a shower plate 32 provided at the bottom of the main body 31. The outer periphery of the main body 31 and the shower plate 32 are sealed with a seal ring (not shown) to form an airtight structure. A space 33 for diffusing gas is formed between the center of the main body 31 and the shower plate 32. For convenience, the space 33 is shown in a simplified shape.

[0014] A first gas inlet 34 and a second gas inlet 35 are formed vertically in the top wall of the lid 22, and these first gas inlet 34 and second gas inlet 35 penetrate the upper wall of the shower head 26 and are connected to the space 33. The shower plate 32 is formed with a plurality of gas discharge holes 37 that extend vertically from the space 33 and penetrate therethrough to face the inside of the chamber 10.

[0015] Therefore, in the showerhead 26 , gas is supplied to the space 33 through the first gas inlet hole 34 and the second gas inlet hole 35 , and the gas mixed in the space 33 is discharged through the gas discharge hole 37 .

[0016] A loading / unloading port 41 for loading and unloading the substrate W is provided on the side wall portion 21a of the chamber main body 21, and this loading / unloading port 41 can be opened and closed by a gate valve 42, allowing the substrate W to be transported between other adjacent modules.

[0017] The mounting table 12 has a generally circular shape in a plan view and is fixed to the bottom 21b of the chamber 10. A temperature regulator 45 that regulates the temperature of the mounting table 12 is provided inside the mounting table 12. The temperature regulator 45 may be configured, for example, with a temperature regulation medium flow path through which a temperature regulation medium (such as water) that regulates the temperature circulates, or a resistance heater. The temperature regulator 45 regulates the temperature of the mounting table 12 to a desired temperature, thereby controlling the temperature of the substrate W placed on the mounting table 12.

[0018] The gas supply mechanism 13 includes an HF gas supply source 51, an Ar gas supply source 52, an NH 3 gas supply source 53, and an N 2 gas supply source .

[0019] The HF gas supply source 51 supplies HF gas as a fluorine-containing gas. Here, HF gas is exemplified as the fluorine-containing gas, but other fluorine-containing gases such as F2 gas, ClF3 gas, and NF3 gas can also be used.

[0020] The NH gas supply source 53 supplies NH gas as a basic gas. Here, NH gas is exemplified as the basic gas, but other than NH gas, amine gas can also be used as the basic gas. Examples of amine include methylamine, dimethylamine, and trimethylamine.

[0021] The Ar gas supply source 52 and the N2 gas supply source 54 supply N2 gas and Ar gas as inert gases that also function as dilution gas, purge gas, and carrier gas. However, both may be Ar gas or N2 gas. Furthermore, the inert gases are not limited to Ar gas and N2 gas, and other rare gases such as He gas can also be used.

[0022] These gas supply sources 51 to 54 are connected to one end of first to fourth gas supply pipes 61 to 64, respectively. The first gas supply pipe 61, which is connected to the HF gas supply source 51, has the other end connected to the first gas inlet hole 34. The second gas supply pipe 62, which is connected to the Ar gas supply source 52, has the other end connected to the first gas supply pipe 61. The third gas supply pipe 63, which is connected to the NH3 gas supply source 53, has the other end connected to the second gas inlet hole 35. The fourth gas supply pipe 64, which is connected to the N2 gas supply source 54, has the other end connected to the third gas supply pipe 63.

[0023] HF gas, which is a fluorine-containing gas, and NH gas, which is a basic gas, along with Ar gas and N gas, which are inert gases, respectively, reach the shower head 26 via the first gas inlet hole 34 and the second gas inlet hole 35, and are discharged into the chamber 10 from the gas outlet hole 37 of the shower head 26.

[0024] A flow rate control unit 65 that opens and closes the flow paths and controls the flow rates is provided in the first to fourth gas supply pipes 61 to 64. The flow rate control unit 65 is composed of, for example, an on-off valve and a flow rate controller such as a mass flow controller (MFC) or a flow control system (FCS).

[0025] The exhaust mechanism 14 has an exhaust pipe 72 connected to an exhaust port 71 formed in the bottom 21b of the chamber 10, and further has an automatic pressure control valve (APC) 73 for controlling the pressure inside the chamber 10 and a vacuum pump 74 for evacuating the inside of the chamber 10, both of which are provided on the exhaust pipe 72.

[0026] Two capacitance manometers 76a, 76b for high pressure and low pressure are provided on the side wall of the chamber 10 to control the pressure inside the chamber 10. A temperature sensor (not shown) for detecting the temperature of the substrate W is provided near the substrate W placed on the mounting table 12.

[0027] The chamber 10, shower head 26, and mounting table 12 that make up the etching apparatus 1 are made of a metal material such as aluminum. A coating such as an oxide coating may be formed on the surfaces of these components. For example, in the case of aluminum, an anodized oxide coating (Al2O3) may be used as the coating. A ceramic coating may also be used.

[0028] The etching apparatus 1 further includes a control unit 80. The control unit 80 is a computer The etching apparatus 1 is made up of a main control unit with a CPU, an input device, an output device, a display device, and a storage device (storage medium). The main control unit controls the operation of each component of the etching apparatus 1. The main control unit controls each component based on a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device. The storage medium stores a processing recipe as a control program, and processing by the etching apparatus 1 is performed based on the processing recipe.

[0029] The etching apparatus of FIG. 1 may have auxiliary means for exciting gases by plasma or the like, but it is preferable that the etching apparatus is one that performs non-plasma etching processing.

[0030] <Etching method> Next, a description will be given of an embodiment of an etching method performed by the above-described etching apparatus 1. The following etching method is performed under the control of the control unit 80.

[0031] FIG. 2 is a flowchart illustrating an etching method according to one embodiment. First, a substrate W having a material containing Si and O is placed in the chamber 10 (Step 1). Specifically, the substrate W is carried into the chamber 10 and placed on the mounting table 12 whose temperature is controlled by the temperature controller 45.

[0032] An example of the structure of the substrate W is shown schematically in Fig. 3. In the example of Fig. 3, the substrate W has a SiO2 film 101, which is a material containing Si and O and serves as an etching target, and a SiN film 102, which is a non-etching material, formed on a base body (not shown). However, the structure of the substrate W is not limited to that shown in Fig. 3.

[0033] In the example of FIG. 3, the SiO2 film 101 can be etched at a desired selectivity to the SiN film 102. However, the non-etching material that can provide a desired selectivity when etching the SiO2 film 101 is not limited to SiN, and any material containing Si and N and / or C can be used. Such materials include Si N, S One or more materials selected from iOCN, SiOC, SiCN, and SiC can be used, and these materials are typically formed as films.

[0034] In addition, the material to be etched is not limited to SiO2, and one or more selected from SiO2, SiON, SiOCN, and SiOC can be used as long as it contains Si and O. These are typically formed as films. Among these, materials other than SiO2 can also be used as Si N, S It is possible to etch with a desired selectivity for iOCN, SiOC, SiCN, and SiC.

[0035] SiOCN and SiOC are low-k (low-k) films, and can be used as both etching target films and non-etching films. For example, when both etching target films and non-etching films are SiOCN or SiOC films, those with low C concentration can be used. (< 6at%) is used as the etching target film. 、C High concentration (<10%)It is possible to use it as a non-etching film.

[0036] A typical example is the case where an SiO2 film is used as the etching target and an SiN film is used as the non-etching material, as described above, but it is also suitable to use an SiOCN film, which is a low-k film, as the non-etching material.

[0037] Next, an inert gas (Ar gas, N2 gas) is supplied from the gas supply mechanism 13 into the chamber 10 to stabilize the temperature of the substrate W and the pressure inside the chamber 10 (step 2).

[0038] Next, while the inert gas is being supplied from the gas supply mechanism 13, a first period in which a basic gas, for example, NH3 gas, is supplied and a second period in which a fluorine-containing gas, for example, HF gas, is supplied are repeated, with at least a portion of the second period not overlapping with the first period (step 3).

[0039] Next, the reaction product produced in step 3 is removed by heating (step 4). In the case of a combination of NH3 gas and HF gas, ammonium silicofluoride (AFS) is produced as a reaction product.

[0040] A typical example of step 3 is shown in Figure 4. Figure 4 also shows steps 2 and 4. Following the stabilization of step 2, inert gases (Ar gas and N2 gas) continue to flow into the chamber. A first period T1 is started during which a basic gas (NH3 gas) is supplied. After the first period T1 ends, a second period T2 is started during which a fluorine-containing gas (HF gas) is continuously supplied. The first period T1 and the second period T2 are repeated. Then, after step 3, a heat treatment is performed (third period T3) to remove the reaction product of step 4.

[0041] In step 3, the first period T1 and the second period T2 may be partially overlapped as shown in Fig. 5. Furthermore, as shown in Fig. 6, a fourth period T4 for purging the chamber 10 may be inserted between the second period T2 and the next first period T1. Here, the purging is performed by flowing only inert gas (Ar gas and N2 gas). The series of processes, in which the supply of the basic gas in the first period T1 and the supply of the fluorine-containing gas in the second period T2 are repeatedly performed, followed by the heat treatment in the third period T3, may be repeated once or more than once.

[0042] As described above, typical examples of basic gases include NH3 gas and HF gas, but other examples of basic gases include amine gas, and other examples of fluorine-containing gases include F2 gas, ClF3 gas, and NF3 gas.

[0043] The mechanism of step 3 will be described below by taking the example of etching the SiO2 film 101 shown in FIG. 3 using NH3 gas as the basic gas and HF gas as the fluorine-containing gas. First, during a first period T1 during which NH3 gas is supplied, the supplied NH3 gas is adsorbed onto the surface of the substrate W, as shown in FIG. 7A. Next, during a second period T2, the supplied HF gas reacts with the adsorbed NH3 gas and the SiO2 film 101, as shown in FIG. 7B, to generate ammonium silicofluoride (AFS) 104 as a reaction product. By repeating this process two or more times, the reaction product AFS 104 is formed at a desired depth, as shown in FIG. 7C.

[0044] On the other hand, in the conventional method, as shown in Fig. 8A, the supply of NH gas is started first, and then HF gas is supplied while NH gas is still being supplied. This causes a reaction that continuously generates AFS 104, as shown in Fig. 8B. As etching progresses, the amount of AFS 104 generated increases, as shown in Fig. 8C, and etching of the SiN film 102 progresses due to the reaction between AFS 104 and excess NH, reducing selectivity to the SiN film 102.

[0045] In this embodiment, as described above, the amount of AFS 104 generated is determined by the amount of NH gas adsorbed during the first period T1, making it easy to finely control the amount of AFS 104. Furthermore, during the second period T2, almost only HF gas is supplied, and NH gas is not supplied or, if supplied, is only supplied in an overlapping amount. This allows for good control of the amount of AFS generated, suppressing etching of the SiN film 102 due to the reaction between AFS 104 and NH as in the conventional method, and enabling etching of the SiO film 101 with high selectivity. Furthermore, since etching proceeds in the presence of AFS, a reaction product, the desired etching amount can be maintained. Furthermore, the presence of AFS on the surface can be considered the same as a state in which NH and HF are already adsorbed on the surface, shortening the incubation time of the etching reaction.

[0046] The same applies when other basic gases and fluorine-containing gases are used, and when materials containing Si and O other than SiO2 are used as the etching target.

[0047] As described above, in step 3, a pulsed gas supply is performed in which a basic gas is first supplied, followed by a fluorine-containing gas, and this is repeated; the fluorine-containing gas is not supplied first. Supplying the fluorine-containing gas first would result in an extremely low etching amount. Furthermore, as described above, the chamber 10 may be purged between the second period T2 in which the fluorine-containing gas is supplied and the first period T1 in which the next basic gas is supplied. However, purging is not performed between the first period T1 and the second period T2. Purging at this timing would remove the basic gas (NH3 gas) adsorbed on the surface, making it difficult for the etching reaction to occur.

[0048] In step 3, the balance between the etching amount (etching rate) and the selectivity can be appropriately adjusted by the lengths of the first period T1 and the second period T2, the flow rates of the basic gas and the fluorine-containing gas, the number of times the first period T1 and the second period T2 are repeated, whether or not purging is performed, etc.

[0049] The longer the first period T1 or the second period T2, the greater the etching amount (etching rate), and the shorter the period, the greater the selectivity. Furthermore, the more times the first period T1 and the second period T2 are repeated up to the third period T3, which removes reaction products such as AFS, the greater the etching amount (etching rate), and the fewer the number of repetitions, the greater the selectivity. The lengths of the first period T1 and the second period T2 are preferably 0.5 to 10 seconds, and the number of repetitions of the first period T1 and the second period T2 up to the third period T3 is preferably 2 to 10. When efficiency is emphasized and a high etching rate is desired, it is preferable to lengthen the first period T1 or the second period T2 and / or increase the number of repetitions within these ranges. When selectivity is emphasized over efficiency, it is preferable to shorten the period T1 or the second period T2 and / or reduce the number of repetitions within these ranges.

[0050] Furthermore, the etching amount (etching rate) increases as the flow rates of the basic gas such as NH3 gas and the fluorine-containing gas such as HF gas increase, and the selectivity tends to increase as the flow rates decrease. The flow rate of the basic gas is preferably in the range of 20 to 500 sccm, and the flow rate of the fluorine-containing gas is preferably in the range of 20 to 500 sccm.

[0051] Furthermore, by purging the chamber 10 after the second period T2 in which the fluorine-containing gas is supplied, excess gas is discharged, thereby further increasing the selectivity while maintaining the etching amount. However, the processing time is lengthened by the fourth period T4 in which the purge is performed. In the above example, the purge is performed by supplying a purge gas such as Ar gas or N2 gas while evacuating the chamber 10, but it may also be performed by simply evacuating the chamber 10. If purging is performed, the fourth period T4 in which the purge is performed is preferably 0.5 to 5 seconds.

[0052] The temperature during etching with a basic gas and a fluorine-containing gas performed during the first period T1 and the second period T2 of step 2 is preferably 80°C or less, more preferably 60 to 80°C. By setting the temperature at 80°C or less, reaction products such as AFS remain, allowing for etching with good controllability as described above. Furthermore, the pressure during etching is preferably in the range of 2.67 to 6666 Pa (0.02 to 50 Torr). The higher the pressure, the greater the amount of etching (etching rate) and the lower the selectivity.

[0053] The heat treatment for removing the reaction products in step 4 can be performed after step 3 is completed by heating the substrate W and evacuating the chamber 10 while supplying an inert gas such as Ar gas or N2 gas. The heating temperature may be the same as that in step 3, but performing the heat treatment at a higher temperature can improve the removal efficiency. Step 4 may be performed in a chamber separate from chamber 10. The time for the heat treatment for removing the reaction products varies depending on the amount of reaction products generated, but is preferably 15 to 120 seconds. By periodically performing the heat treatment for removing the reaction products, the reaction products (AFS) are completely removed, the chamber 10 is refreshed, and the process stability is improved.

[0054] In step 3, as described above, the first period T1 during which the basic gas is supplied and the second period T2 during which the fluorine-containing gas is supplied are pulsed, thereby enabling etching of SiO2 films and the like with a high selectivity, but surface roughness and loading may become a problem depending on the conditions.

[0055] If surface roughness becomes a problem, it is effective to increase the number of times the first period T1 and the second period T2 are repeated or to increase the processing pressure. However, since increasing the number of times the process is repeated or increasing the pressure decreases the selectivity (increasing shoulder loss), the conditions must be set appropriately according to the required characteristics. It is also possible to achieve both of these characteristics by changing the conditions (multi-step processing), such as increasing the pressure only for the last few times.

[0056] Loading is a phenomenon in which the etching amount differs between dense and sparse patterns. If loading becomes a problem, it is effective to increase the number of repetitions, extend the first period T1 and / or the second period T2, increase the flow rate of the basic gas and / or the fluorine-containing gas, increase the pressure, etc.

[0057] As mentioned above, the structure of the substrate W is not limited to that shown in Fig. 3 and may have various other structures, for example, as shown in Fig. 9, it may be formed by alternately stacking a plurality of SiN films 202 and SiO2 films 203 on a base 201 made of Si or the like. In the substrate W having such a structure, when the SiO2 film 203 is thin, about 1 to 5 nm, it is difficult to sufficiently remove the SiO2 film 203 if the selectivity is low as in the conventional case, but the etching method of the present embodiment can provide good removal performance.

[0058] <Experimental Example> Next, an experimental example will be described. Here, a SiO2 film was etched using NH3 gas and HF gas in the apparatus shown in Figure 1 for a substrate with the structure shown in Figure 9, according to patterns 1 to 4 described below. The thicknesses of the SiO2 film were 3 nm and 5 nm. Common conditions were a substrate temperature of 60 to 80°C, a pressure of 2.67 to 6666 Pa (0.02 to 50 Torr), an NH3 gas flow rate of 20 to 500 sccm, an HF gas flow rate of 20 to 500 sccm, an Ar gas flow rate of 10 to 5000 sccm, and an N2 gas flow rate of 10 to 10,000 sccm.

[0059] In pattern 1, as shown in Figure 10, Ar gas, N2 gas, and NH3 gas are first flowed and stabilized, and then HF gas is supplied for 3.0 seconds while these gases are still flowing, and then AFS removal processing is performed for 60 seconds. In (conventional pattern) pattern 1, this sequence was repeated 18 times.

[0060] In Pattern 2, as shown in Figure 11, Ar gas, N2 gas, and NH3 gas are first supplied and stabilized, and then, while these gases are still flowing, HF gas is supplied twice in a pulsed manner with a supply time of 1.5 seconds, and then AFS removal processing is performed for 60 seconds (HF pulse). In Pattern 2, this sequence was repeated 22 times.

[0061] In pattern 3, as shown in Fig. 12, Ar gas and N gas are first supplied and stabilized, and then NH gas and HF gas are simultaneously supplied twice in a pulsed manner with a supply time of 1.5 seconds while these gases are still supplied, followed by AFS removal processing for 60 seconds (synchronous pulse). This sequence was repeated 21 times in pattern 3.

[0062] 13, pattern 4 is a sequence in which Ar gas and N gas are first flowed and stabilized, and then, while these gases are kept flowing, NH gas and HF gas are alternately supplied twice for a supply time of 1.5 seconds, and then AFS removal processing is performed for 60 seconds (embodiment). In pattern 4, this sequence was repeated 61 times.

[0063] The etching amount, the SiN film shoulder loss (SiN shoulder loss) calculated from the CD difference, and the selectivity of the SiO film to the SiN film when etching with these patterns 1 to 4 are shown in Figures 14, 15, and 16, respectively. As shown in Figure 14, there was no significant difference in the etching amount among patterns 1 to 4. In contrast, as shown in Figure 15, the SiN shoulder loss calculated from the CD difference was significantly smaller for pattern 4, which is an embodiment, than for the others. Furthermore, as shown in Figure 16, the selectivity also achieved a value of over 100 for pattern 4, which was significantly larger than patterns 1 to 3, which had a value of around 20.

[0064] <Other applications> Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0065] For example, the apparatuses of the above-described embodiments are merely examples, and apparatuses with various configurations can be applied. Furthermore, although a semiconductor wafer is exemplified as the substrate, the substrate is not limited to a semiconductor wafer, and may be other substrates such as an FPD (flat panel display) substrate, typified by an LCD (liquid crystal display) substrate, or a ceramic substrate. [Explanation of symbols]

[0066] 1. Etching equipment 10; Chamber 12;Placement table 13: Gas supply mechanism 14;Exhaust mechanism 26. Shower head 45;Temperature controller 51;HF gas supply source 53;NH3 gas source 80;Control unit 101,203;SiO2 film 102,202;SiN film 201;Substrate W; substrate

Claims

1. An etching method for selectively etching a material containing Si and O, comprising: providing a substrate having etching and non-etching targets in a chamber; repeating a first period of supplying a basic gas that is initiated first and a second period of supplying a fluorine-containing gas that is initiated next, such that at least a portion of the second period does not overlap with the first period; a step of removing by heating a reaction product produced by supplying the basic gas and the fluorine-containing gas; and The etching target is a material containing Si and O, and the non-etching target is a material containing Si and N and / or C, and the material containing Si and O is SiO ２ , SiON, SiOCN, SiOC, and the material containing Si and N and / or C is selected from SiN, SiOCN, SiOC, SiCN, SiC (provided that the material containing Si and O is SiO ２ and the material containing Si and N and / or C is SiN or SiOCN. an etching method in which, when the material containing Si and O to be etched and the material containing Si and N and / or C to be non-etched are both SiOCN or both SiOC, the C concentration of the SiOCN or SiOC to be etched is relatively low, and the C concentration of the SiOCN or SiOC to be non-etched is relatively high.

2. providing a substrate having a first SiOC-containing film and a second SiOC-containing film in a chamber, the first SiOC-containing film having a lower C concentration than the second SiOC-containing film; a step of selectively etching the first SiOC-containing film relative to the second SiOC-containing film by repeating a first period in which a basic gas is supplied into the chamber and a second period in which a fluorine-containing gas is supplied into the chamber; a step of removing by heating reaction products produced by the etching step; and In the etching step, the first period starts before the second period, and at least a portion of the second period does not overlap with the first period.

3. 3. The etching method according to claim 2, wherein the first SiOC-containing film and the second SiOC-containing film are both SiOCN films.

4. 3. The etching method according to claim 2, wherein the first SiOC-containing film and the second SiOC-containing film are both SiOC films.

5. The basic gas is NH ３ The etching method according to any one of claims 1 to 4, wherein

6. 5. The etching method according to claim 1, wherein the basic gas is an amine gas.

7. 7. The etching method of claim 6, wherein the amine gas is selected from the group consisting of methylamine, dimethylamine, and trimethylamine.

8. The fluorine-containing gas is HF gas, F ２ Gas, ClF ３ Gas and NF ３ 8. The etching method of claim 1, wherein the gas is selected from the group consisting of:

9. An etching apparatus for selectively etching a material containing Si and O, comprising: a chamber containing a substrate having etching and non-etching targets; a mounting table on which the substrate is placed within the chamber; a gas supply unit that supplies a basic gas and a fluorine-containing gas into the chamber; an exhaust unit that exhausts the inside of the chamber; a temperature control unit that controls the temperature of the substrate on the mounting table; A control unit; Equipped with The etching target is a material containing Si and O, and the non-etching target is a material containing Si and N and / or C, and the material containing Si and O is SiO ２ , SiON, SiOCN, SiOC, and the material containing Si and N and / or C is selected from SiN, SiOCN, SiOC, SiCN, SiC (provided that the material containing Si and O is SiO ２ and the material containing Si and N and / or C is SiN or SiOCN. When the material containing Si and O to be etched and the material containing Si and N and / or C to be non-etched are both SiOCN or both SiOC, the C concentration of the SiOCN or SiOC to be etched is relatively low, and the C concentration of the SiOCN or SiOC to be non-etched is relatively high, the control unit controls the gas supply unit, the exhaust unit, and the temperature adjustment unit so as to repeat a first period in which the basic gas is supplied and a second period in which the fluorine-containing gas is supplied, the first period being started first, so that at least a portion of the second period does not overlap with the first period, and so as to heat and remove reaction products generated by the supply of the basic gas and the fluorine-containing gas.

10. a chamber accommodating a substrate having a first SiOC-containing film and a second SiOC-containing film, the first SiOC-containing film having a lower C concentration than the second SiOC-containing film; a mounting table on which the substrate is placed within the chamber; a gas supply unit that supplies a basic gas and a fluorine-containing gas into the chamber; an exhaust unit that exhausts the inside of the chamber; a temperature control unit that controls the temperature of the substrate on the mounting table; A control unit; Equipped with the control unit repeats a first period in which a basic gas is supplied into the chamber and a second period in which a fluorine-containing gas is supplied into the chamber, thereby selectively etching the first SiOC-containing film with respect to the second SiOC-containing film; a step of removing by heating reaction products produced by the etching step; wherein, in the etching step, the first period is started before the second period, and the gas supply unit, the exhaust unit, and the temperature adjustment unit are controlled so that at least a portion of the second period does not overlap with the first period.

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