Plasma processing equipment

Abstract

To improve the controllability of the pattern.SOLUTION: A method for processing a substrate in a plasma processing vessel is provided. The method includes a process for providing a substrate having a base layer to be etched and a mask on the base layer. The method also includes the process of forming a protective film on the mask. The method also includes the process of performing an anisotropic deposition to form a deposition layer on top of the protective film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed below include: Plasma processing equipment Regarding. [Background technology]

[0002] In recent years, various mask patterning technologies have attracted attention due to the continuous increase in integration density. Double patterning and quadrature patterning are examples of such technologies. Extreme ultraviolet lithography (EUVL) and patterning have also been widely researched. When one-dimensional layout patterns with fine spacing are realized using EUV lithography, high-precision critical dimension (CD) control is required for subsequent etching. For example, XY CD controllability at the atomic scale and reduction of local variations are required. Indicators of local variations include line edge roughness (LER), line width roughness (LWR), and local critical dimension uniformity (LCDU).

[0003] For example, a method and apparatus for smoothing the edges of features patterned using EUVL has been proposed (see, for example, Patent Document 1), and a technique for reducing mask loss that occurs during etching of high aspect ratio holes has also been proposed (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2018 / 0190503 [Patent Document 2] US Patent Application Publication No. 2018 / 0233357 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides techniques that can improve pattern controllability. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a method for processing a substrate in a plasma processing chamber. The method includes providing a substrate having an underlying layer to be etched and a mask over the underlying layer. The method also includes forming a protective film over the mask. The method also includes performing anisotropic deposition to form a deposition layer on top of the protective film.

[0007] A method according to one aspect of the present disclosure is a method for processing a substrate in a plasma processing chamber. The method includes providing a substrate having an underlying layer to be etched and a mask on the underlying layer. The method further includes: x H y F z and at least one of N2, O2, H2, and F in a predetermined ratio, and exposing the substrate to the plasma. x H y F z In the above equation, (i) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 1, and z is a natural number greater than or equal to 0, or (ii) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 0, and z is a natural number greater than or equal to 1.

[0008] A method according to one aspect of the present disclosure is a method for processing a substrate in a plasma processing chamber. The method includes providing a substrate having an underlying layer to be etched and a mask on the underlying layer. The method further includes: x H y F z and at least one of N2, O2, H2, and F in a predetermined ratio. The method also includes forming a protective film on the mask. The method also includes performing anisotropic deposition to form a deposition layer on top of the protective film. xH y F z In the above equation, (i) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 1, and z is a natural number greater than or equal to 0, or (ii) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 0, and z is a natural number greater than or equal to 1. [Effects of the Invention]

[0009] According to the present disclosure, pattern controllability can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a flowchart illustrating an example of a substrate processing method according to an embodiment. [Figure 2] FIG. 2 is a schematic view for explaining an example of a substrate processing method according to an embodiment. [Figure 3] FIG. 3 is a diagram illustrating the mechanism of anisotropic deposition according to one embodiment. [Figure 4] FIG. 4 is a diagram for explaining anisotropic deposition according to one embodiment. [Figure 5] FIG. 5 is a diagram showing experimental results according to one embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the aspect ratio of a processing target pattern and the adhesion coefficient of gas to the sidewall of the pattern. [Figure 7] FIG. 7 is a diagram showing the relationship between the aspect ratio of a processing target pattern and the ion density at the bottom of the pattern. [Figure 8A] FIG. 8A is a diagram for explaining the reduction in the mask of the comparative example. [Figure 8B] FIG. 8B is a diagram illustrating mask enhancement by anisotropic deposition according to one embodiment. [Figure 9] FIG. 9 is a diagram showing the etching selectivity of a film formed by anisotropic deposition according to one embodiment. [Figure 10A]FIG. 10A is a diagram showing example patterns obtained by an exemplary process and a comparison process according to one embodiment. [Figure 10B] FIG. 10B is a graph showing the experimental results of FIG. 10A. [Figure 11] FIG. 11 is a diagram illustrating LCDU improvement effects of an exemplary process according to one embodiment. [Figure 12] FIG. 12 is a diagram for explaining the mechanism of Direct Current Superposition (DCS). [Figure 13] FIG. 13 is a diagram showing a schematic configuration of a capacitively coupled plasma (CCP) type plasma system. [Figure 14] FIG. 14 is a diagram showing a schematic configuration of an inductively coupled plasma (ICP) type plasma system. DETAILED DESCRIPTION OF THE INVENTION

[0011] The disclosed embodiments will be described in detail below with reference to the accompanying drawings. Note that the embodiments are not limited to the embodiments. Furthermore, the embodiments can be appropriately combined as long as the processing contents are not contradictory.

[0012] As mentioned above, pattern roughness is a major issue in lithography technology in semiconductor manufacturing. Various attempts have been made to reduce the roughness of features after lithography and before etching. However, it is not easy to improve LCDU while maintaining the desired CD.

[0013] (Method according to one embodiment) The method according to the embodiment described below improves LCDU and XY CD controllability. Figure 1 is a flowchart of an example of a substrate processing method according to the embodiment. Figure 2 is a schematic diagram for explaining an example of a substrate processing method according to the embodiment.

[0014] First, a substrate 100 is provided (step S101, FIG. 2(a)). A plurality of layers are formed on the substrate 100. For example, an underlayer 101 (a layer to be etched), an anti-reflection film 102, a mask 103, and the like are formed in this order (see FIG. 2(a)). The mask 103 may be formed by EUVL and may have a predetermined pattern. Then, a protective film 200 is formed on the mask 103 (step S102, FIG. 2(b)). Anisotropic deposition is performed on the protective film 200 (step S103, FIG. 2(c)). The conditions for the anisotropic deposition in step S103 are set so that a layer 104 of deposit is selectively formed on a top portion TP of the mask 103. For example, the layer 104 is formed substantially only on the top portion TP of the mask 103, and is not formed on a bottom portion BTM and / or a sidewall SD of the pattern on the substrate 100. Therefore, the anisotropic deposition in step S103 effectively increases the thickness of the mask 103 by the layer 104. Further, XY CD control may be performed (step S104). For XY CD control, redeposition, which will be described later, may be used. After step S104, etching is performed to etch the underlayer 101 (step S105, FIG. 2(d)). Further additional processing may be performed (step S106). This completes the processing according to one embodiment.

[0015] Here, the substrate 100 may be a silicon (Si) substrate.

[0016] The underlayer 101 may include one or more layers, such as an oxide, a metal (hafnium, cobalt, tungsten, titanium, etc.) or a metal oxide, a conductive film (titanium silicide, titanium nitride, cobalt silicide, etc.), a dielectric material (silicon oxide, silicon nitride, spin-on glass (SOG), etc.), a hard mask material (amorphous carbon, amorphous silicon, etc.), etc.

[0017] The anti-reflective coating 102 may be a silicon-containing anti-reflective coating (SiARC) or a nitrogen-free anti-reflective coating (NFARL). The undercoat 101 may include a spin-on carbon (SOC) layer.

[0018] The mask 103 may be a mask made of an organic material such as photoresist. The mask 103 may be an organic photoresist mask formed by EUV lithography. The mask 103 may also be a hard mask. The hard mask may be a carbon-containing film. The mask 103 may contain a metal such as tungsten (W) or titanium (Ti).

[0019] The protective film 200 may be an inorganic film. The protective film 200 may contain silicon. The protective film 200 may be SiO x or SiN x The protective film 200 may contain a metal. The protective film 200 may be formed by DCS (Direct Current Superposition), chemical vapor deposition (CVD), physical vapor deposition (PVD), or ALD. DCS will be described later. In the above explanation, the protective film 200 is described as a layer of deposits. Alternatively, the protective film 200 may be the surface of the mask 103. In this case, the surface of the mask 103 is modified (hardened) by DCS using a processing gas such as argon gas to function as the protective film 200. The protective film 200 has a thickness of at least one atomic layer. For example, the protective film 200 has a thickness of 1 to 2 nanometers.

[0020] The layer 104 may include carbon.

[0021] The method for forming the film is not particularly limited. For example, CVD, PVD, ALD, and other methods can be used for film formation. Similarly, etching can be achieved by dry etching, atomic layer etching (ALE), and the like. In the anisotropic deposition in step S103, C x H y A process gas containing at least one of N2, O2, H2, and F can be used. For example, a process gas containing methane (CH4) and nitrogen (N2) can be used. The process gas preferably does not contain fluoride (F). The process gas preferably contains C x H y Fz where (i) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 1, and z is zero or a natural number greater than or equal to 1, or (ii) x is a natural number greater than or equal to 1, y is zero or a natural number greater than or equal to 1, and z is a natural number greater than or equal to 1. In one embodiment, each process may be performed in the same plasma processing chamber or system, or each process may be performed in different processing chambers or systems.

[0022] 1, the XY CD control is described as being performed after the anisotropic deposition (step S103). However, the process for the XY CD control may be performed before the anisotropic deposition (step S103). The process for the XY CD control may also be performed before the protective film 200 is formed (i.e., before step S102). For example, the balanced plasma process described below may be performed before the protective film 200 is formed.

[0023] (anisotropic deposition) 1, anisotropic deposition is performed in step S103. Next, the details of anisotropic deposition will be described.

[0024] Here, anisotropic deposition refers to a film formation process in which deposits are deposited to form a layer substantially only on the surface of a pattern extending in one direction, and not on the surface extending in the other direction. In one embodiment, a layer of deposits is formed substantially only on the top of the pattern on the substrate, and not on the bottom or sidewalls of the pattern. Anisotropic deposition can be achieved by adjusting various process conditions. In this embodiment, anisotropic deposition is achieved by balancing the film formation effect and the etching effect.

[0025] FIG. 3 illustrates an anisotropic deposition mechanism according to one embodiment. In the example of FIG. 3, a pattern having a top TP, sidewalls SD, and a bottom BTM is formed on a substrate. When a deposition process is performed on this pattern, a thicker layer of deposits is formed on the top TP than on the bottom BTM or sidewalls SD, due to, for example, a loading effect. On the other hand, when an etching process is performed on this pattern, the amount of etching may be the same on the top TP and the bottom BTM. In other words, when different gases, such as carbon (C) gas that contributes to the formation of deposits on the pattern and nitrogen gas (N*, N+) that contributes to the etching of the pattern, are simultaneously supplied to the substrate for plasma processing, the etching effect and the deposition effect cancel each other out on the bottom BTM, while the deposition effect may be more pronounced on the top TP than the etching effect. In the example of FIG. 3, a layer of deposits may be formed only on the top TP.

[0026] FIG. 4 is a diagram for explaining anisotropic deposition according to one embodiment.

[0027] In Figure 4, "Initial State" shows the vertical cross section of the photoresist mask after exposure as the initial state. "CH4 / N2:60s" shows the state of the photoresist mask after 60 seconds of anisotropic deposition using a process gas containing CH4 and N2. "N2:60s" shows the state of the photoresist mask after 60 seconds of processing with N2 gas. "CH4:20s" shows the state of the photoresist mask after 20 seconds of processing with CH4 gas.

[0028] As shown in Figure 4, when a 60-second process was performed using CH4 gas (primarily a deposition gas) and N2 gas (primarily an etching gas), neither the CD nor the mask height changed substantially from the size observed in the initial state. On the other hand, when a 60-second process was performed using N2 gas alone, the mask was essentially removed. Furthermore, when a 20-second process was performed using CH4 gas alone, the mask height increased from 35.6 nm to 40.2 nm, but the overall mask shape was distorted and the CD decreased from 30.8 nm to 28.2 nm. This suggests that the desired CD and mask height can be achieved by performing both deposition and etching using balanced conditions in a single process. Here, we refer to anisotropic deposition, which achieves a balance between deposition and etching effects in a single process, as a "balanced plasma process."

[0029] FIG. 5 illustrates experimental results according to one embodiment. In the example shown in FIG. 5, a substrate with a photoresist mask formed thereon was used. A pattern was then formed on the mask as shown in FIG. 5 ("Initial State" in FIG. 5). Next, the mask pattern was modified with argon gas plasma generated by applying a direct current to the upper electrode in the processing chamber. Anisotropic deposition according to this embodiment was then performed using a processing gas containing CH4 and N2. The anisotropic deposition processing times were 0 seconds ("Example 1" in FIG. 5), 240 seconds ("Example 2" in FIG. 5), and 480 seconds ("Example 3" in FIG. 5). As can be clearly seen from FIG. 5, when anisotropic deposition was not performed ("Example 1" in FIG. 5), the vertical cross section of the originally rectangular mask pattern was distorted at the top and became trapezoidal. On the other hand, when anisotropic deposition according to this embodiment was performed, the mask height was substantially increased as shown in Examples 2 and 3. In addition, anisotropic deposition resulted in improved LWR.

[0030] (Factors contributing to anisotropic deposition) There are various factors that contribute to anisotropic deposition, such as the partial pressure in the plasma processing chamber in which the anisotropic deposition is performed, the sticking coefficient, the substrate temperature, and the charge density or ion density.

[0031] Figure 6 shows the relationship between the aspect ratio of the target pattern and the sticking coefficient of the gas on the sidewall of the pattern. As can be seen from Figure 6, the lower the sticking coefficient, the greater the amount of radicals transported into the hole. The higher the sticking coefficient, the fewer radicals are transported into the hole, making it less likely that a deposit layer will form on the sidewall or bottom of the hole. Therefore, the difference in sticking coefficients can be used to control the amount of deposition on the pattern sidewall. For this reason, it is preferable to use a combination of gases with high sticking coefficients, such as C4F6, SiCl4, and CH4, and gases with low sticking coefficients, such as O2 and N2, for anisotropic deposition.

[0032] FIG. 7 is a diagram showing the relationship between the aspect ratio of a pattern to be processed and the ion density at the bottom of the pattern. When the ion density at the bottom of the pattern is low, the amount of deposits on the bottom decreases. In other words, the loading effect increases. As shown in FIG. 7, the lower the energy (eV) of the generated plasma, the lower the ion density at the bottom. This means that lower energy is preferable to utilize the loading effect.

[0033] The amount of deposition can also be controlled based on the applied voltage. The amount of deposition can also be controlled based on the temperature of an electrostatic chuck (ESC) on which the substrate is placed. The amount of deposition increases as the temperature of the ESC decreases. The ESC may also be divided into one or more sections, allowing the temperature of each section to be controlled independently. The amount of deposition can then be controlled based on the temperature of each section of the ESC. This may improve the uniformity of the amount of deposition on the substrate placed on the ESC.

[0034] The process conditions for anisotropic deposition according to one embodiment can be set taking into consideration the above factors.

[0035] (Mask Enhancement) Next, the effect of mask reinforcement according to this embodiment will be described. As described above, when the mask 103 is a photoresist mask formed by EUVL, the thickness of the mask 103 tends to be thin. For example, the thickness of the mask 103 is about 50 nanometers. Therefore, when etching is performed from above the mask 103, the mask 103 is quickly removed by the etching.

[0036] In this embodiment, anisotropic deposition is performed to build up the mask (thicken the mask), after which further processing may be performed.

[0037] 8A is a diagram illustrating film loss of a mask in a comparative example, and FIG. 8B is a diagram illustrating mask reinforcement by anisotropic deposition according to one embodiment.

[0038] On the sample substrate S of FIG. 8A, a base layer ML, an anti-reflective coating (ARC), and a photoresist mask PR are formed in this order. Furthermore, a protective film PF is formed on the photoresist mask PR. In the example of FIG. 8A, the protective film PF was formed using a method such as DCS (see FIG. 12). Then, a redeposition process was performed.

[0039] Here, the redeposition process includes a film formation process and a sputtering process. If the material to be sputtered in the subsequent sputtering process is already present in the pattern, the film formation process may be omitted. First, in the film formation process, deposits are formed on the pattern by a film formation method such as chemical vapor deposition. Next, in the sputtering process, accelerated ions of a process gas are bombarded with the pattern on the substrate. The process gas is, for example, a rare gas such as argon. The ion bombardment causes deposit particles in the pattern to fly out of the pattern and redeposit on the pattern surface at a position close to the point of flight. For patterns containing holes, particles may fly out of relatively large holes, but may redeposit on the sidewalls of relatively small holes. Redeposition can be used, for example, to achieve X>Y shrink. Here, redeposition is described as an example, but other methods of XY control may also be used.

[0040] As shown in Figure 8A (2), when the redeposition process was performed on the sample substrate of Figure 8A (1), the upper end of the photoresist mask PR and part of the anti-reflective film (SiARC) were removed by etching, and the cross section of the ideally rectangular photoresist mask PR changed to a trapezoidal shape.

[0041] FIG. 8B illustrates mask enhancement by anisotropic deposition according to one embodiment. Using a substrate similar to that shown in FIG. 8A, a protective film PF was first formed using DCS, as in the example shown in FIG. 8A. Next, anisotropic deposition according to this embodiment was performed on the protective film PF. The resulting pattern is shown in (1) of FIG. 8B. As can be seen from (1) of FIG. 8B, the mask height was significantly increased by anisotropic deposition, and the original photoresist mask PR was sufficiently retained. Subsequently, redeposition was performed under the same conditions as in FIG. 8A. Despite the redeposition, the rectangular cross section of the photoresist mask PR remained substantially unchanged, and the particles ejected by sputtering were mainly deposited on the sidewalls of the anti-reflective coating (SiARC) ((2) of FIG. 8B). As a result, the shape of the photoresist mask PR was substantially maintained while the mask height was significantly increased. Thus, according to one embodiment, even if redeposition is performed multiple times to achieve the desired XY CD, mask thickness loss and pattern deformation may be avoided.

[0042] (Improved etching selectivity) When the mask height is increased by anisotropic deposition, the etch selectivity of the mask is also improved.

[0043] FIG. 9 shows the etching selectivity of a film formed by anisotropic deposition according to one embodiment. In FIG. 9, the etching selectivity of a mask formed by anisotropic deposition ("TOPDEPO" in FIG. 9), the etching selectivity of a photoresist mask formed by EUV lithography (see PR in FIG. 8A) ("EUV" in FIG. 9), and the etching selectivity of a film formed by DCS (see PF in FIG. 8A) ("DCS" in FIG. 9) are compared. When the photoresist mask PR was etched using CF4 for 10 seconds, approximately 20 nanometers of the photoresist mask PR was removed. On the other hand, the removal amount of the mask formed using anisotropic deposition according to this embodiment was approximately 10 nanometers. Thus, the mask formed by anisotropic deposition according to this embodiment has a higher etching selectivity than an untreated EUV photoresist mask PR. Furthermore, when argon gas was used instead of CF4 for 120 seconds, substantially the same results were obtained.

[0044] In this manner, when anisotropic deposition according to one embodiment is performed, the pattern CD can be maintained while improving the mask height and mask quality (ie, etch selectivity).

[0045] (XY CD control) Figure 10A shows example patterns obtained by an exemplary process and a comparative process according to one embodiment, and Figure 10B is a graph showing the experimental results of Figure 10A.

[0046] In example (1) of Figure 10A, the pattern ("initial state") was subjected to DCS and redeposition for XY CD control. As shown in Figure 10A, the elliptical pattern narrowed as a result of redeposition. When the applied voltage was 200 (pulsed) watts + 200 watts, the mask pattern was blocked. When the applied voltage was 3300 watts + 200 watts, the hole pattern disappeared (referred to as mask break).

[0047] In the example (2) of FIG. 10A, for the other party, the pattern was subjected to anisotropic deposition according to an embodiment, and then re-deposition was performed for X-Y CD control. As can be seen from (2) of FIG. 10A, the elliptical holes maintain their original shape regardless of the value of the applied voltage. Further, the CD is maintained and the X / Y ratio is also well controlled.

[0048] As shown in FIG. 10B, in Comparative Example (1), mask occlusion and mask breakage occurred. When anisotropic deposition of this embodiment was performed using the same processing conditions as in this case (that is, making the voltage values applied to the electrodes in the processing container the same), a much higher ΔX / ΔY ratio was obtained as compared with the comparative example. Also, the CD hardly changed. Thus, it was confirmed that the anisotropic deposition of this embodiment has the effect of improving X-Y CD controllability.

[0049] Here, X-Y CD control means controlling the critical dimensions of the pattern in two perpendicular directions, that is, the X direction and the Y direction. For example, assume that a pattern is formed including a plurality of holes each having an elliptical horizontal cross section. The axis along one axis of the elliptical shape, for example, the X direction, is shorter than the axis along the other axis, for example, the Y direction.

[0050] Here, the control for reducing the dimension of the pattern in the Y direction rather than in the X direction is called "X<Y shrinkage" or "X<Y control". Also, the control for reducing the dimension of the pattern in the X direction rather than in the Y direction is called "X>Y shrinkage" or "X>Y control". Also, the control for reducing the dimension of the pattern by approximately the same amount in both the X direction and the Y direction is called "X=Y shrinkage" or "X=Y control".

[0051] (LCDU improvement) The inventors confirmed that when equilibrium plasma treatment was performed on the EUV mask, the LCDU was improved. FIG. 11 is a diagram showing the LCDU improvement effect obtained by an exemplary process according to an embodiment.

[0052] In Example (1) of Figure 11, a 70-nm-thick spin-on carbon (SOC) layer was formed on a silicon substrate. A 10-nm-thick SiARC film was then formed on the SOC layer. A 35-nm-thick EUV mask was then formed on the SiARC film. After exposure, the LCDU (3σ) and CD were measured. The CD was 28.87 nm and the LCDU was 3.59. After sequential isostatic plasma treatment and etching, the CD was 27.05 nm and the LCDU was 2.01. Thus, the isostatic plasma treatment improved the LCDU without significantly reducing the CD. In Example (2) of Figure 11, the thickness of the SOC layer and the SiARC film were changed to 130 nm and 20 nm, respectively. In the initial state after exposure, the CD was 25.33 nm and the LCDU was 4.35. After sequential isostatic plasma treatment and etching, the CD was 25.45 nm and the LCDU was 2.97. Thus, LCDU was improved without a significant decrease in CD in all samples.

[0053] (DCS) The protective film 200 (see step S102 in FIG. 1 and FIG. 2(b)) may be formed using DCS. FIG. 12 is a diagram illustrating the mechanism of DCS. DCS is a method of processing a substrate by applying a negative DC voltage to an upper electrode in a plasma processing chamber and causing a material such as silicon contained in the upper electrode to fall onto a substrate placed below the upper electrode. DCS can be performed, for example, by the method described in U.S. Patent Application Publication No. 2018 / 0151333.

[0054] DCS can be used to form a film on a wafer. DCS can also be used to modify the mask 103, for example, by using a process gas containing H2 / N2. In this embodiment, DCS is used to form a protective film 200 on the mask 103. To form the protective film 200, a target may also be placed on the substrate.

[0055] (Device example) To achieve anisotropic deposition according to the present embodiment, a plasma processing apparatus for performing anisotropic deposition preferably includes a mechanism for supplying high-frequency power to an upper structure, i.e., an upper electrode. When a high-frequency voltage for plasma generation is supplied from a lower structure (i.e., a lower electrode), deposits tend to be transported to the bottom of the pattern. Therefore, to achieve the anisotropic deposition according to the present embodiment, an inductively coupled plasma (ICP) apparatus or a capacitively coupled plasma (CCP) apparatus in which high-frequency power is applied to an upper electrode may be used.

[0056] FIG. 13 shows a capacitively coupled plasma (CCP) type plasma system. The system of FIG. 13 includes a process vessel 1, an upper electrode 3, and a lower electrode 4. RF power supplied from radio frequency power sources (RF sources) 6 and 7 is coupled to the upper electrode 3 and the lower electrode 4. The power coupling may include different RF frequencies. The lower electrode 4 includes an electrostatic chuck (ESC) 5 for supporting and holding a substrate W. A gas supply source 8 is connected to the process vessel 1 and supplies process gas into the process vessel 1. An exhaust device 9, such as a turbomolecular pump (TMP), is connected to the process vessel 1 and evacuates the process vessel 1. As radio frequency power is supplied to at least one of the upper electrode 3 and the lower electrode 4, a plasma 2 is generated between the upper electrode 3 and the lower electrode 4. Alternatively, multiple RF power sources 6 and 7 may be coupled to the same electrode. A variable direct current (DC) power source 10 may also be coupled to the upper electrode 3.

[0057] 14 is a diagram showing an inductively coupled plasma (ICP) type plasma system. This system includes a process vessel 11, a dielectric window 21, and a lower electrode 14. An inductor (coil) 20 is disposed on the dielectric window 21. RF power from radio frequency power sources (RF sources) 16 and 17 is coupled to the coil 20 and the lower electrode 14, respectively. The lower electrode 14 includes an electrostatic chuck (ESC) 15, which supports and holds a substrate W. A gas supply source 18 is connected to the process vessel 11 and supplies a process gas into the process vessel 11. An exhaust device 19, such as a turbomolecular pump (TMP), is also connected to the process vessel 11 and evacuates the process vessel 11. When radio frequency power is supplied to at least one of the dielectric window 21 and the lower electrode 14, a plasma 12 is generated between the dielectric window 21 and the lower electrode 14.

[0058] It should be noted that the isostatic plasma treatment may be performed before the formation of the protective film 200 for XY CD control.

[0059] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0060] [Appendix 1] A processing vessel; a substrate support table provided in the processing chamber; a plasma generating unit that generates plasma in the processing chamber; a gas supply unit connected to the processing vessel; A control unit; An apparatus for processing a substrate, comprising: The control unit providing a substrate having an underlying layer to be etched and a mask on the underlying layer; forming a protective film on the mask; performing anisotropic deposition to form a deposition layer on top of the protective film; The apparatus causes each part of the apparatus to perform each step including the steps.

[0061] [Appendix 2] A processing vessel; a substrate support table provided in the processing chamber; a plasma generating unit that generates plasma in the processing chamber; a gas supply unit connected to the processing vessel; A control unit; An apparatus for processing a substrate, comprising: The control unit providing a substrate having an underlying layer to be etched and a mask on the underlying layer; C x H y F z and generating a plasma from a process gas containing at least one of N2, O2, H2, and F in a predetermined ratio, and exposing the substrate to the plasma; Said C x H y F z In (i) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 1, and z is a natural number greater than or equal to 0, or (ii) x is a natural number greater than or equal to 1, y is a natural number greater than or equal to 0, and z is a natural number greater than or equal to 1. An apparatus for causing each part of the apparatus to execute the method described above. [Explanation of symbols]

[0062] 1,11 Processing vessel 2,12 Plasma 3 Upper electrode 4,14 Lower electrode 5,15 Electrostatic chuck 6,7,16,17 RF power supply 8,18 Gas Source 9,19 Exhaust system 10 Variable DC power supply 20 Derivatives (coils) 21 Dielectric window 100 boards 101 Base layer 102 Anti-reflection coating 103 Mask 200 protective film

Claims

1. A processing vessel; a substrate support table for supporting a substrate in the processing chamber, the substrate having an EUV mask stacked on a base layer; a gas supply unit that supplies a processing gas into the processing vessel at a predetermined rate; a plasma generating unit that generates plasma from the processing gas and exposes the substrate to the plasma in an isostatic plasma processing, the isostatic plasma processing including simultaneously performing a film formation processing and an etching processing of the EUV mask; Equipped with The process gas is C ｘ H ｙ F ｚ a deposition gas comprising: (i) x is a natural number of 1 or more, y is a natural number of 1 or more, and z is zero or a natural number of 1 or more, or (ii) x is a natural number of 1 or more, y is zero or a natural number of 1 or more, and z is a natural number of 1 or more; N ２ , O ２ and H ２ an etching gas containing at least one of Including, The predetermined ratio is determined such that the resulting etching process and film deposition process are performed simultaneously during the equilibrium plasma process, and the resulting etching process of the EUV mask is at least partially offset by the resulting film deposition process during the equilibrium plasma process, and during the equilibrium plasma process, the effect of the film deposition process on the effect of the etching process at the top of the EUV mask on the substrate is higher than the effect of the film deposition process on the effect of the etching process at the bottom or sidewalls of the pattern of the EUV mask on the substrate.

2. The plasma processing apparatus of claim 1 , wherein the gas supply unit and the plasma generation unit are configured to etch the underlayer after the equilibrium plasma processing is completed.

3. The plasma processing apparatus according to claim 2 , wherein the base layer is etched in the processing chamber.

4. 3. The plasma processing apparatus of claim 2, wherein the gas supply unit and the plasma generation unit control the balanced plasma processing such that an LCDU(3σ) of the EUV mask after the balanced plasma processing and etching of the underlayer is smaller than an LCDU(3σ) of the EUV mask after forming the EUV mask but before performing the balanced plasma processing.

5. The process gas is CH ４ and N ２ The plasma processing apparatus according to claim 1 , further comprising:

6. The plasma processing apparatus of claim 1 , wherein the gas supply unit and the plasma generation unit are configured to form a protective film after the isostatic plasma processing is completed.

7. an upper electrode and a lower electrode provided in the processing chamber; The plasma processing apparatus of claim 1 , wherein the lower electrode includes an electrostatic chuck that supports and holds the substrate.

8. The plasma processing apparatus according to claim 7 , wherein the plasma generating unit is coupled to at least one of the upper electrode and the lower electrode.

9. 8. The plasma processing apparatus of claim 7, wherein a variable DC power supply is coupled to the upper electrode.

10. a dielectric window; an inductive element disposed above the dielectric window; The bottom electrode and Furthermore, The plasma processing apparatus of claim 1 , wherein the lower electrode includes an electrostatic chuck that supports and holds the substrate.

11. The plasma processing apparatus according to claim 10 , wherein the plasma generating unit is coupled to at least one of the inductive element and the lower electrode.

12. The plasma processing apparatus according to claim 1 , further comprising an exhaust unit that exhausts the inside of the processing chamber.

13. The plasma processing apparatus according to claim 12, wherein the exhaust device includes a turbomolecular pump.

14. The plasma processing apparatus according to claim 2 , wherein the underlayer is etched in a separate processing chamber.

15. 10. The plasma processing apparatus of claim 1, wherein during the isostatic plasma processing, a layer is formed on the top of the EUV mask on the substrate, but the layer is not formed on the bottom or sidewalls of the pattern of the EUV mask on the substrate.

16. The plasma processing apparatus of claim 15 , wherein the layer comprises carbon.

17. 2. The plasma processing apparatus according to claim 1, wherein the substrate is a silicon substrate.

18. The plasma processing apparatus according to claim 1 , wherein the EUV mask is an organic photoresist mask.

19. The plasma processing apparatus of claim 18 , wherein the EUV mask comprises tungsten or titanium.

20. The plasma processing apparatus of claim 1 , wherein the underlayer is an oxide, a metal, a metal oxide, a conductive film, a dielectric material, or a hard mask material.

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