Etching method and etching apparatus

Abstract

This invention provides an etching method and an etching apparatus capable of suppressing the distribution of etching amount between substrates. Multiple substrates housed in a vacuum chamber each have a first processing object and a second processing object. The first processing object is a silicon oxide layer (53), and the second processing object is a silicon nitride layer (51) or a silicon layer (52) covered by the silicon oxide layer (53). The etching method includes the following steps: a first step, introducing NH3 gas and HF gas into the vacuum chamber to etch the first processing object; and a second step, after the first step, supplying plasma generated from a gas containing NH3 gas and NF3 gas into the vacuum chamber to etch the second processing object.

Description

Technical Field

[0001] This invention relates to etching methods and etching apparatus. Background Technology

[0002] An oxide film removal apparatus is known to remove the native oxide film formed on the surface of a silicon substrate by etching. In this apparatus, an etchant for the native oxide film is generated using free radicals contained in a microwave-generated plasma. The generated etchant transforms the native oxide film into a silicon-containing complex. The thermal decomposition temperature of the complex is lower than that of the native oxide film. Furthermore, the oxide film removal apparatus vaporizes the complex from the silicon substrate by heating the complex and the silicon substrate together. Thus, the oxide film removal apparatus removes the native oxide film from the silicon substrate. This apparatus can process multiple silicon substrates simultaneously (see, for example, Patent Document 1).

[0003] Furthermore, it is known that etching can be performed in the same manner as the aforementioned oxide film removal apparatus without utilizing microwave-generated plasma. By changing the type of gas used in etching, oxide film removal can be performed without using plasma.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2012 / 002393 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Furthermore, in the case of a batch processing apparatus that processes multiple substrates simultaneously, various gases used to generate etchant are blown from the outer periphery of the substrates into the processing tank of the apparatus. The etchant blown from the outer periphery undergoes an etching reaction and is consumed by the substrate surface, while simultaneously being propelled to an exhaust section provided within the processing tank. Therefore, the etchant concentration is distributed during processing within the processing tank according to the amount consumed. Consequently, the etching rate on the substrate surface is also distributed, and the target etching amount is also distributed.

[0009] It should be noted that this problem arises not only when the substrate to be etched has a silicon oxide layer, but also when it has a silicon nitride layer. Furthermore, it is known that the larger the surface area of ​​the object being etched, the more significant the impact.

[0010] Furthermore, in plasma etching, the free radicals used in the generation of the etchant lose their excited state through collisions with other gases or the walls of the induced free radical induction tube or dispersion mechanism. Therefore, in multiple silicon substrates, the amount of excited free radicals arriving between the silicon substrates varies depending on the shape of the free radical induction tube or dispersion mechanism in the oxide film removal apparatus. Consequently, the amount of oxide film etched also varies between the silicon substrates.

[0011] Methods for solving problems

[0012] In the etching method for solving the above-mentioned problems, multiple substrates housed in a vacuum tank each have a first processing object and a second processing object. The first processing object is a silicon oxide layer, and the second processing object is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The method includes the following steps: a first step, introducing NH3 gas and HF gas into the vacuum tank to etch the first processing object; and a second step, after the first step, supplying plasma generated by a gas containing NH3 gas and NF3 gas into the vacuum tank to etch the second processing object.

[0013] According to the above etching method, since NH3 gas and HF gas are used to etch the first object in the first process, the amount of etching between the substrates is less likely to be distributed compared with the case where plasma is used for etching in the first and second processes.

[0014] In the above etching method, at least one of the NH3 gas inlet for introducing NH3 gas into the vacuum tank and the HF gas inlet for introducing HF gas into the vacuum tank is the target port. The method may include a modification step, whereby the position of the target port is changed before the first step, thereby changing the distance between the center of the substrate and the target port. According to this etching method, by changing the distance between the target port and the center of the substrate, the distribution of the etching amount within the surface of the substrate can be changed.

[0015] In the above etching method, either the NH3 gas inlet for introducing NH3 gas into the substrate or the HF gas inlet for introducing HF gas into the substrate is a target port. The method may include a setting step, in which the flow rate of the gas supplied by each of the multiple target ports is independently set before the first step.

[0016] According to the above etching method, the flow rate of the gas supplied by each object port can be set. Therefore, by changing the flow rate of the gas introduced by one object port, or changing the ratio of the flow rate of the gas supplied by the first object port to the flow rate of the gas supplied by the second object port, the etching distribution in the surface of the substrate can be changed.

[0017] In the above etching method, the setting step can maintain the total flow rate of gas introduced through all the target ports and change the flow rate of gas introduced through each of the target ports. According to this etching method, since the flow rate of gas introduced through the target ports is changed without changing the total flow rate of gas introduced into the vacuum chamber, the gas distribution within the substrate surface can be changed while suppressing pressure fluctuations within the vacuum chamber. Therefore, the distribution of the etching amount within the substrate surface can be changed.

[0018] In the etching apparatus for solving the above-mentioned problems, the substrate includes a first processing object and a second processing object, wherein the first processing object is a silicon oxide layer and the second processing object is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The etching apparatus includes: a vacuum chamber for accommodating a plurality of the substrates; a first processing unit for introducing NH3 gas and HF gas into the vacuum chamber to etch the first processing object; and a second processing unit for introducing plasma generated by a gas containing NH3 gas and NF3 gas into the vacuum chamber after etching the first processing object to etch the second processing object.

[0019] According to the above etching apparatus, since the first processing unit uses NH3 gas and HF gas to etch the first processing object, the etching amount between the substrates is less likely to be distributed compared to the case where both the first processing unit and the second processing unit use plasma for etching.

[0020] The etching apparatus described above may include an NH3 gas inlet for introducing NH3 gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber. At least one of the NH3 gas inlet and the HF gas inlet is a target port. The etching apparatus has a plurality of candidates for the target ports. The distance between the center of the substrate and one of the candidates and the distance between the center and other candidates may be different.

[0021] According to the above etching apparatus, since it has multiple candidate objects for the target aperture, the distance between the target aperture and the center of the substrate may change between selecting the first candidate object and selecting the second candidate object. Therefore, the distribution of the etching amount within the surface of the substrate may change between selecting the first candidate object and selecting the second candidate object.

[0022] The etching apparatus described above may include an NH3 gas inlet for introducing NH3 gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber. At least one of the NH3 gas inlet and the HF gas inlet is a target port. The etching apparatus may further include a moving mechanism to move the target port to change the distance between the center of the substrate and the target port.

[0023] According to the above etching apparatus, the moving mechanism moves the object port, thereby changing the distance between the object port and the center of the substrate, and thus changing the distribution of the etching amount in the surface of the substrate.

[0024] The etching apparatus described above may include an NH3 gas inlet for introducing NH3 gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber. Either the NH3 gas inlet or the HF gas inlet is a target port. The etching apparatus has multiple target ports, and each target port may have a flow control unit for controlling the flow rate of the gas supplied from that target port. According to this etching apparatus, since one flow control unit is provided for each target port, the degree of freedom in combining the flow rates of the gas supplied from each target port can be increased.

[0025] In the etching apparatus described above, the flow control unit can control the flow rate of the gas to maintain the total flow rate of the gas introduced through all the object ports and change the flow rate of the gas introduced through each of the object ports.

[0026] According to the above etching apparatus, since the flow control unit changes the flow rate of the gas introduced through the target port without changing the total gas flow rate, it is possible to change the gas distribution within the substrate surface while suppressing pressure fluctuations within the vacuum chamber. This allows for modification of the etching amount distribution within the substrate surface.

[0027] An etching apparatus for solving the above-mentioned problems includes: a vacuum chamber for accommodating multiple substrates; a first gas inlet for introducing NH3 gas into the vacuum chamber; a second gas inlet for introducing HF gas into the vacuum chamber; and a mechanism for changing the distance between the first gas inlet and the second gas inlet.

[0028] According to the above etching apparatus, since the distance between the first gas inlet for introducing NH3 gas and the second gas inlet for introducing HF gas can be changed, the position of the etchant synthesized in the vacuum tank for etching the silicon oxide layer can be changed, thereby adjusting the etching distribution on the substrate surface.

[0029] The etching apparatus described above may include a third gas inlet for introducing NF3 gas and a fourth gas inlet for introducing NH3 gas after discharge by the discharge tube.

[0030] According to the above etching apparatus, for silicon nitride layers and silicon layers that are not etched in etching without the use of plasma, plasma etching can be used in combination, which can improve the freedom of etching selectivity of silicon nitride films and silicon layers.

[0031] In the above-described etching apparatus, NH3 gas introduced through one flow path is branched into two or more of the first gas inlets, and HF gas introduced through one flow path is branched into two or more of the second gas inlets. The etching apparatus has a mechanism that, by selecting the branching of NH3 gas and HF gas, changes the distance between the target port of the NH3 gas inlet selected from the two or more of the first gas inlets and the HF gas inlet selected from the two or more of the second gas inlets.

[0032] According to the above etching apparatus, the distance between the first gas inlet for introducing NH3 gas and the second gas inlet for introducing HF gas can be changed, thereby changing the position of the etchant synthesized in the vacuum tank for etching the silicon oxide layer, and thus adjusting the etching distribution on the substrate surface.

[0033] In the above etching apparatus, NH3 gas introduced through one flow path can be branched into flow paths with different conductivity, and HF gas introduced through one flow path can be branched into flow paths with different conductivity.

[0034] According to the above etching apparatus, not only can the position of the etchant be pre-adjusted based on the distance of the inlet, but also the distribution of the gas used to generate the etchant can be pre-adjusted, thus enabling further freedom in adjusting the etching distribution within the substrate surface.

[0035] In the etching apparatus described above, NH3 gas introduced through one flow path can be branched into two or more of the first gas inlets, and HF gas introduced through one flow path can be branched into two or more of the second gas inlets. Each branched flow path can be equipped with a flow control unit.

[0036] According to the above etching apparatus, by equipping each inlet with a flow control unit, the gas distribution for generating a finer etchant can be adjusted, and the distribution adjustment within the substrate surface can be made more flexible.

[0037] In the above-described etching apparatus, the first gas inlet and the second gas inlet are arranged such that the gases introduced by the first gas inlet and the second gas inlet flow parallel to the substrate and to each other, respectively, by being arranged on a plane orthogonal to the normal of the substrate. The apparatus may have a mechanism for rotating and moving the first gas inlet and the second gas inlet about an axis parallel to the normal of the substrate provided in the vacuum chamber.

[0038] According to the above etching apparatus, the positional relationship and angle of the inlet can be continuously set, and the position of the etchant synthesized in the vacuum tank can be further precisely changed.

[0039] The etching method for solving the above-mentioned problem includes the following treatment of a plurality of substrates housed in a vacuum chamber: a first treatment performed by introducing NH3 gas and HF gas into the vacuum chamber; and a second treatment performed by supplying plasma generated by a gas containing the NH3 gas and NF3 gas into the vacuum chamber.

[0040] In the above etching method, the object of the first treatment can be a silicon oxide layer, and the object of the second treatment can be a silicon nitride layer or a silicon layer covered by the silicon oxide layer.

[0041] According to the above etching method, for silicon nitride layers and silicon layers that are not etched in etching without plasma, plasma etching can be used in combination, which can improve the freedom of etching selectivity of silicon nitride films and silicon layers.

[0042] In the above etching method, the second process can be performed after the first process.

[0043] According to the above etching method, the first process will no longer experience the etch distribution caused by free radicals that occurred in the first process.

[0044] In the above etching method, in the first process, the NH3 gas introduced by one flow path is branched into two or more first gas inlets, and the HF gas introduced by one flow path is branched into two or more second gas inlets. By selecting the branching of the NH3 gas and the HF gas, the distance between the target port of the NH3 gas inlet selected from the two or more first gas inlets and the target port of the HF gas inlet selected from the two or more second gas inlets can be changed.

[0045] According to the above etching method, the distance between the first gas inlet for introducing NH3 gas and the second gas inlet for introducing HF gas can be changed. Therefore, the position of the etchant synthesized in the vacuum tank for etching the silicon oxide layer can be changed, thereby adjusting the etching distribution on the substrate surface.

[0046] In the above etching method, the NH3 gas introduced by one flow path is branched into flow paths with different conductivity, and the HF gas introduced by one flow path is branched into flow paths with different conductivity. The NH3 gas and the HF gas can be introduced into the target port of the NH3 gas inlet and the target port of the HF gas inlet at their respective different flow rates.

[0047] According to the above etching method, not only can the position of the etchant be pre-adjusted based on the distance of the inlet, but also the distribution of the gas used to generate the etchant can be pre-adjusted, thus enabling further freedom in adjusting the etching distribution within the substrate surface.

[0048] In the above etching method, during the first process, NH3 gas introduced through one flow path is branched into two or more first gas inlets, and HF gas introduced through one flow path is branched into two or more second gas inlets. By selecting the branching of NH3 gas and HF gas, the distance between the target port of the NH3 gas inlet selected from the two or more first gas inlets and the target port of the HF gas inlet selected from the two or more second gas inlets can be changed. Furthermore, each branched flow path can be equipped with a flow control unit to introduce NH3 gas and HF gas at different flow rates through the target ports of the NH3 gas inlet and the HF gas inlet, respectively.

[0049] According to the above etching method, the distribution of the gas used to generate the etchant can be further precisely adjusted in advance, thus enabling greater freedom in adjusting the etching distribution within the substrate surface.

[0050] In the above etching method, during the first process, NH3 gas is introduced through a first gas inlet and HF gas is introduced through a second gas inlet. The first and second gas inlets are configured such that the gases introduced through them flow parallel to and parallel to the substrate, respectively, by being positioned on a plane orthogonal to the normal of the substrate. Furthermore, by rotating the first and second gas inlets around an axis parallel to the normal of the substrate within the vacuum chamber, the distance between the first and second gas inlets, as well as the introduction angles of the NH3 gas and HF gas, can be changed.

[0051] According to the above etching method, the positional relationship and angle of the inlet can be continuously set, and the position of the etchant synthesized in the vacuum tank can be further precisely changed. Attached Figure Description

[0052] Figure 1 This is a diagram illustrating the configuration of an etching apparatus in one embodiment.

[0053] Figure 2 It is shown Figure 1 The diagram shows the configuration of the processing chamber of the etching apparatus.

[0054] Figure 3 It is shown Figure 2 A schematic diagram of the candidates for the NH3 gas inlet and the HF gas inlet of the processing chamber shown.

[0055] Figure 4 This is a schematic diagram showing the relationship between the candidate for the NH3 gas inlet and the candidate for the HF gas inlet and the substrate.

[0056] Figure 5 This is a timing diagram used to illustrate an etching method in one embodiment.

[0057] Figure 6 This is a flowchart illustrating one step in the etching process.

[0058] Figure 7 This is a flowchart illustrating one step in the etching process.

[0059] Figure 8 This is a flowchart illustrating one step in the etching process.

[0060] Figure 9 This is a graph showing the selectivity of the silicon oxide layer relative to the silicon layer.

[0061] Figure 10 This is a graph showing the selectivity ratio of the silicon nitride layer to the silicon layer.

[0062] Figure 11 This is a graph showing the relationship between the location in the substrate and the amount of etching.

[0063] Figure 12 This is a graph showing the relationship between the distance between the inlet ports and the amount of etching.

[0064] Figure 13 This is a schematic diagram showing candidates for the NH3 gas inlet and the HF gas inlet in a modified example of the etching apparatus. Detailed Implementation

[0065] Reference Figures 1 to 12 An embodiment of the etching method and etching apparatus will be described.

[0066] [Etching apparatus]

[0067] Reference Figures 1 to 4 The etching apparatus will be described.

[0068] Figure 1 The etching apparatus 10 shown is configured to simultaneously etch multiple substrates. Each substrate includes a first processing target and a second processing target. The first processing target is a silicon oxide layer. The second processing target is a silicon nitride layer, or a silicon layer covered by the silicon oxide layer serving as the first processing target.

[0069] The etching apparatus 10 includes a processing chamber 11 and a transfer chamber 12. The processing chamber 11 is an example of a vacuum chamber for storing a substrate. The etching of the substrate is performed in the processing chamber 11. In the transfer chamber 12, the substrate before etching is transferred from the outside of the processing chamber 11 to the transfer chamber 12, and the substrate after etching is transferred out to the outside of the transfer chamber 12.

[0070] Gate valve 13 is located between processing chamber 11 and transfer / in chamber 12. Gate valve 13 has an open state and a closed state. By opening gate valve 13, the space defined by processing chamber 11 is connected to the space defined by transfer / in chamber 12. Conversely, by closing gate valve 13, the space defined by processing chamber 11 is separated from the space defined by transfer / in chamber 12.

[0071] The processing chamber 11 includes a first heating unit 11A and an exhaust unit 11B. The first heating unit 11A simultaneously heats multiple substrates located within the processing chamber 11. For example, the first heating unit 11A adjusts the temperature of the substrates located within the space defined by the processing chamber 11 to a predetermined chamber temperature. The chamber temperature and the substrate temperature can be the same or different. The exhaust unit 11B depressurizes the pressure within the processing chamber 11 to a predetermined pressure.

[0072] The etching apparatus 10 includes a nitrogen (N2) gas supply unit 21, an ammonia (NH3) gas supply units 22 and 23, a hydrogen fluoride (HF) gas supply unit 24, and a nitrogen trifluoride (NF3) gas supply unit 25. NH3, HF, and NF3 gases are used to generate the etchant for etching the substrate, and N2 gas is a carrier gas supplied to the substrate along with the NH3, HF, and NF3 gases.

[0073] Each supply unit 21, 22, 23, 24, 25 is, for example, a mass flow controller, connected to a storage cylinder containing the gas supplied by each supply unit 21, 22, 23, 24, 25. The mass flow controller is an example of a flow control unit. A valve is provided between each supply unit 21, 22, 23, 24, 25 and the gas it supplies. By opening the valve, the gas supplied by each supply unit 21, 22, 23, 24, 25 flows into the gas supplied. Conversely, by closing the valve, the gas supplied by each supply unit 21, 22, 23, 24, 25 does not flow into the gas supplied.

[0074] The etching apparatus 10 includes a discharge tube 26, a waveguide 27, and a microwave source 28. Microwaves oscillated by the waveguide 27 from the microwave source 28 are irradiated onto the discharge tube 26. Of the supply units 21, 22, 23, 24, and 25, the NH3 gas supply unit 22 and the N2 gas supply unit 21 are connected to the discharge tube 26. By irradiating the discharge tube 26 with microwaves while NH3 and N2 gases are supplied, the NH3 and N2 gases are excited. That is, plasma is generated from the mixture of NH3 and N2 gases. H2 is generated through the excitation of the mixed gas. * NH * NH2 * and N2 * .

[0075] The N2 gas supply unit 21 and the NH3 gas supply unit 22 are connected to the discharge tube 26 via a pipe.

[0076] NH3 gas supply unit 23, HF gas supply unit 24 and NF3 gas supply unit 25 are connected to the processing chamber 11. NH3 gas supply unit 23, HF gas supply unit 24 and NF3 gas supply unit 25 are connected to the processing chamber 11 via separate piping.

[0077] The ventilation gas supply unit 12A is connected to the transfer chamber 12. The ventilation gas supply unit 12A supplies ventilation gas, used to cool the etched substrate, into the transfer chamber 12. The ventilation gas can be, for example, N2 gas. The ventilation gas supply unit 12A is, for example, a mass flow controller, and is connected to a storage bottle for storing the ventilation gas.

[0078] The etching apparatus 10 further includes a control unit 10C. The control unit 10C controls the driving of each component included in the etching apparatus 10. As a result, the control unit 10C can use the etching apparatus 10 to etch the first processing object and the second processing object.

[0079] The control unit 10C includes a storage unit 10CM. The storage unit 10CM stores a process recipe. The process recipe includes multiple process steps constituting the process recipe. The process recipe includes relevant setting values ​​for the operation of the processing chamber 11, the transfer chamber 12, and the various parts connected to the processing chamber 11 in each process step. After reading the process recipe, the control unit 10C reads the setting values ​​determined in each process step and generates an instruction corresponding to the read setting values.

[0080] The control unit 10C controls the driving of the NH3 gas supply unit 23 and the HF gas supply unit 24, thereby introducing NH3 gas and HF gas into the processing chamber 11. Then, the control unit 10C controls the driving of the NH3 gas supply unit 22, the NF3 gas supply unit 25, and the microwave source 28, thereby supplying plasma generated from a gas containing NH3 gas and NF3 gas into the processing chamber 11. Thus, the control unit 10C performs the first step, i.e., the first processing, and the second step, i.e., the second processing, included in the etching method implemented in the etching apparatus 10.

[0081] Thus, in the etching apparatus 10 of this embodiment, one example of the first processing unit includes an NH3 gas supply unit 23 and an HF gas supply unit 24. One example of the second processing unit includes an NH3 gas supply unit 22, an NF3 gas supply unit 25, a discharge tube 26, a waveguide tube 27, and a microwave source 28.

[0082] Figure 2 The structure of the processing chamber 11 is shown. It should be noted that... Figure 2 In order to facilitate the explanation of the functional parts of the processing chamber 11 other than the first heating part 11A, the illustration of the first heating part 11A is omitted.

[0083] like Figure 2 As shown, the etching apparatus 10 includes a support portion 10A for supporting substrates S. The support portion 10A supports multiple substrates S in a stacked state with gaps G between them. It should be noted that... Figure 2 In this process, the support portion 10A is located within the processing chamber 11, and the etching apparatus 10 includes a mechanism that allows the support portion 10A to move between the transfer-in / exit chamber 12 and the processing chamber 11. Thus, with the gate valve 13 open, the etching apparatus 10 moves the support portion 10A from the transfer-in / exit chamber 12 to the processing chamber 11, or from the processing chamber 11 to the transfer-in / exit chamber 12.

[0084] The substrate S is, for example, circular. As described above, the substrate S includes a first processed object and a second processed object. When the second processed object is a silicon layer, the second processed object is formed of polysilicon. In this case, the first processed object is an oxide of polysilicon. Multiple substrates S are supported by the support portion 10A with a gap G left in the direction in which the multiple substrates S are stacked. The gap G is, for example, 5 mm or more and 20 mm or less.

[0085] The gas dispersion tube 11C is located inside the processing chamber 11. The gas dispersion tube 11C has a plurality of holes for dispersing the gas supplied to the gas dispersion tube 11C within the processing chamber 11.

[0086] A spray head 11D, separate from the gas dispersion tube 11C, is installed in the processing chamber 11. The spray head 11D has an inlet. Since the inlet of the spray head 11D is exposed within the space defined by the processing chamber 11, various gases are introduced into the processing chamber 11 through the inlet of the spray head 11D.

[0087] The NH3 gas supply unit 22 is connected to the spray head 11D via the discharge tube 26. The NF3 gas supply unit 25 is connected to the gas dispersion tube 11C without the discharge tube 26 and the spray head 11D.

[0088] The NH3 gas supply unit 23, HF gas supply unit 24 and NF3 gas supply unit 25 are respectively connected to their respective piping. The NH3 gas supply unit 23 and HF gas supply unit 24 are connected to the spray head 11D without the aid of the discharge tube 26.

[0089] The processing chamber 11 includes a rotating portion 11E. When the support portion 10A is located within the processing chamber 11, the rotating portion 11E is configured to connect to the support portion 10A. When connected to the support portion 10A, the rotating portion 11E rotates the support portion 10A about its central axis. The rotating portion 11E rotates the support portion 10A from the start to the end of etching for the first and second processing objects. Therefore, in the substrate S, the etching amount at a predetermined position in the radial direction of the substrate S is approximately fixed in the circumferential direction of the substrate S.

[0090] Figure 3 The diagram schematically illustrates the inlets for introducing various gases into the processing chamber 11. It should be noted that... Figure 3 The diagram schematically shows multiple gas inlets corresponding to one substrate S.

[0091] The etching apparatus 10 includes an NH3 gas inlet for introducing NH3 gas into the processing chamber 11, and an HF gas inlet for introducing HF gas into the processing chamber 11. At least one of the NH3 gas inlet and the HF gas inlet is a target port. The NH3 gas inlet is an example of a first gas inlet, and the HF gas inlet is an example of a second gas inlet. The etching apparatus 10 has multiple candidate objects for the target ports. The distance between the center SC of the substrate S and one candidate object is different from the distance between the center SC of the substrate S and other candidates.

[0092] In the etching apparatus 10 disclosed herein, since it has multiple candidate objects for the target aperture, the distance between the target aperture and the center of the substrate can be changed between selecting the first candidate object and selecting the second candidate object. Therefore, the distribution of the etching amount within the surface of the substrate can be changed between selecting the first candidate object and selecting the second candidate object.

[0093] exist Figure 3 In the example shown, both the NH3 gas inlet and the HF gas inlet are target ports. The etching apparatus 10 includes multiple first candidate ports 31 that serve as candidates for NH3 gas inlets and multiple second candidate ports 32 that serve as candidates for HF gas inlets. Each first candidate port 31 is a hole formed in the spray head 11D for introducing NH3 gas into the processing chamber 11. Each second candidate port 32 is a hole formed in the spray head 11D for introducing HF gas into the processing chamber 11. It should be noted that... Figure 3 For ease of illustration, the illustration of the spray head 11D is omitted, and the candidates 31 and 32 are schematically shown.

[0094] In this example, the etching apparatus 10 includes a first candidate group and a second candidate group. In the first candidate group, a first first candidate 31, a second first candidate 31, and a third first candidate 31 are arranged consecutively along one direction. In the second candidate group, a first second candidate 32, a second second candidate 32, and a third second candidate 32 are arranged consecutively. An NH3 gas supply unit 23 is connected to the first candidate group. Figure 3 In the example, the flow path for supplying NH3 gas to the first candidate 31 branches into three flow paths from one flow path connected to the NH3 gas supply unit 23, and each branched flow path is connected to one first candidate 31. An HF gas supply unit 24 is connected to the second candidate group. The flow path for supplying HF gas to the second candidate 32 branches into three flow paths from one flow path connected to the HF gas supply unit 24, and each branched flow path is connected to one second candidate 32.

[0095] On a plane parallel to the plane extended by the substrate S, the distance between the first candidate 31 and the first candidate 32 is the first distance L1, and the distance between the third candidate 31 and the first candidate 32 is the second distance L2. The first distance L1 and the second distance L2 are different. In this example, the first distance L1 is longer than the second distance.

[0096] In this example, the candidate selected is located in the first candidate group. Figure 3 The leftmost candidate 31 is the NH3 gas inlet, and the candidate in the second candidate group is located at... Figure 3 The leftmost second candidate 32 is the HF gas inlet. NH3 gas is supplied into the processing chamber 11 through the NH3 gas inlet, and HF gas is supplied into the processing chamber 11 through the HF gas inlet.

[0097] Viewed from a perspective facing the surface extending from the substrate S, the exhaust section 11B is opposite to the first candidate 31 and the second candidate 32. Thus, the substrate S is positioned between the first candidate 31 and the second candidate 32 and the exhaust section 11B. Therefore, NH3 gas introduced into the processing chamber 11 through the NH3 gas inlet flows towards the exhaust section 11B via the substrate S, and HF gas introduced into the processing chamber 11 through the HF gas inlet flows towards the exhaust section 11B via the substrate S.

[0098] Additionally, the etching apparatus 10 includes an N2 gas inlet 33 and an NF3 gas inlet 34. An N2 gas supply unit 21 is connected to the N2 gas inlet 33. Both the N2 gas supply unit 21 and the NH3 gas supply unit 22 are connected to the N2 gas inlet 33. In this example, the N2 gas inlet 33 is located between the first candidate group and the second candidate group. The NF3 gas supply unit 25 is connected to the NF3 gas inlet 34. In this example, the NF3 gas inlet 34 is located separately from the first candidate group, the second candidate group, and the N2 gas inlet 33. The NF3 gas inlet 34 is an example of a third gas inlet, and the N2 gas inlet 33 is an example of a fourth gas inlet.

[0099] Figure 4 The diagram shows multiple substrates S supported by the support portion 10A, and the relationship between each substrate S and the gas inlet. Furthermore, a method for setting the distance between the target inlet of NH3 gas selected from the first candidate group and the target inlet of HF gas selected from the second candidate group is described below.

[0100] like Figure 4As shown, in the etching apparatus 10, each substrate S is provided with the aforementioned first candidate group (i.e., a plurality of first candidates 31), second candidate group (i.e., a plurality of second candidates 32), N2 gas inlet 33, and NF3 gas inlet 34. In other words, the first candidate group, the second candidate group, one N2 gas inlet 33, and two NF3 gas inlets 34 are associated with each substrate S. During the etching of one substrate S, the gases introduced from the NH3 gas inlet selected from the plurality of first candidates 31, the HF gas inlet selected from the plurality of second candidates 32, the N2 gas inlet 33, and the NF3 gas inlet 34 associated with that substrate S primarily contribute to the etching of that substrate S.

[0101] The first candidate group, the second candidate group, the N2 gas inlet 33, and the NF3 gas inlet 34 associated with one substrate S are located, for example, on the plane extended by the substrate S. Alternatively, in the direction of stacking multiple substrates S, the first candidate group, the second candidate group, the N2 gas inlet 33, and the NF3 gas inlet 34 associated with one substrate S are located above the substrate S and below the substrate S located directly above the substrate S.

[0102] The etching apparatus 10 may further include a moving mechanism to move the object port, thereby changing the distance between the object port selected from the first candidate group and the object port selected from the second candidate group. Thus, by moving the object port using the moving mechanism, the distance between the object port selected from the first candidate group and the object port selected from the second candidate group can be changed, thereby changing the distribution of the etching amount within the surface of the substrate S.

[0103] exist Figure 4 In the example shown, for the NH3 gas inlet, which is one of the target ports, the candidate inlet from the first candidate group is selected before the target port is moved. Figure 4 The second candidate 31, located in the center, serves as the NH3 gas inlet. The etching apparatus 10, for example, switches the opening and closing of the valve located between the NH3 gas supply section 23 and the NH3 gas inlet, thereby selecting from... Figure 4 The first candidate 31, located on the far left of the first candidate group, is used as the NH3 gas inlet. Therefore, the NH3 gas inlet is moved from its original position to its current position.

[0104] It should be noted that the etching apparatus 10 can switch the valve located between the NH3 gas supply section 23 and the NH3 gas inlet that is being supplied, thereby allowing the first candidate group to be processed. Figure 4 Candidate 31 on the far left and Figure 4The first candidate 31, located in the center, was selected as the NH3 gas inlet. This also allows for changes to the position and number of NH3 gas inlets.

[0105] The etching apparatus 10 may include multiple NH3 gas supply units 23. In this case, the number of NH3 gas supply units 23 may be the same as the number of first candidates 31, or it may be less than the number of first candidates 31.

[0106] When the etching apparatus 10 is equipped with multiple NH3 gas supply units 23, the etching apparatus 10 can, for example, switch the NH3 gas supply units 23 used to supply NH3 gas to the processing chamber 11. Thus, the etching apparatus 10 can move the NH3 gas inlet from its previous position to its current position. The etching apparatus 10, through communication with the first candidate group... Figure 4 The NH3 gas supply unit 23 connected to the leftmost first candidate 31 is switched to be connected to the first candidate group. Figure 4 The NH3 gas supply unit 23 connected to the rightmost candidate 31 can switch the position of the NH3 gas inlet.

[0107] Alternatively, the etching apparatus 10 may also be composed of materials from the first candidate group. Figure 4 The leftmost candidate 31 is connected to the NH3 gas supply section 23 and... Figure 4 The rightmost first candidate 31 is connected to the NH3 gas supply unit 23, which supplies NH3 gas from both sides. Thus, the two first candidates 31 are selected as NH3 gas inlets. Consequently, the position and number of NH3 gas inlets can also be changed.

[0108] In this case, in the etching apparatus 10, when only the NH3 gas inlet is set as the target port, each target port is provided with an NH3 gas supply unit 23 that controls the flow rate of NH3 gas supplied from that target port. Since each NH3 gas inlet is provided with one NH3 gas supply unit 23, the degree of freedom in the combination of the flow rates of the gas supplied from each NH3 gas inlet can be increased.

[0109] The NH3 gas supply unit 23 can control the flow rate of NH3 gas by changing the flow ratio of NH3 gas introduced from each target port. For example, before flow control, the gas supply unit 23 can control the flow rate of NH3 gas introduced from each target port. Figure 4 The flow rate of NH3 gas introduced through the leftmost NH3 gas inlet is set to flow rate A, and will be... Figure 4When the flow rate of NH3 gas introduced through the rightmost NH3 gas inlet is set to flow rate B, the total flow rate of NH3 gas is flow rate (A+B). Next, the setting value of the NH3 gas supply unit 23 connected to the leftmost NH3 gas inlet can be changed to flow rate (A-α), and the setting value of the NH3 gas supply unit 23 connected to the rightmost NH3 gas inlet can be changed to flow rate (B+α).

[0110] It should be noted that, for example, by pre-setting a predetermined conductivity in the gas flow path branching off from each target port, the flow rate ratio of NH3 gas introduced through each target port can be set. Alternatively, this conductivity can also be made variable.

[0111] In this case, the gas distribution within the surface of substrate S can be altered. Therefore, the distribution of the etching amount within the surface of substrate S can be changed.

[0112] Alternatively, the etching apparatus 10 may be supplied with NH3 gas by two NH3 gas supply units 23, and one NH3 gas supply unit 23 may supply NH3 gas toward the two first candidates 31. Thus, the etching apparatus 10 can use two NH3 gas supply units 23 to introduce NH3 gas into the processing chamber 11 through three NH3 gas inlets.

[0113] On the other hand, Figure 4 In the example shown, for the HF gas inlet, which is one of the target ports, the candidate in the second candidate group is selected before the target port is moved. Figure 4 The second candidate 32 in the center serves as the HF gas inlet. The etching apparatus 10, for example, switches the opening and closing of the valve located between the HF gas supply section 24 and the HF gas inlet, thereby selecting the candidate from the second candidate group. Figure 4 The second candidate 32, located on the far left, serves as the HF gas inlet. Thus, the HF gas inlet moves from its original position to its current position.

[0114] It should be noted that the etching apparatus 10 can select either of the two second candidates 32 in the second candidate group as HF gas inlets by switching the valve located between the HF gas supply unit 24 and the HF gas inlet that is being supplied. This also allows for changing the position and number of HF gas inlets.

[0115] Alternatively, the etching apparatus 10 may have multiple HF gas supply units 24, similar to the NH3 gas supply unit 23. In this case, it may have the same number of HF gas supply units 24 as the second candidate 32, or it may have fewer HF gas supply units 24 than the second candidate 32.

[0116] [Etching Method]

[0117] Reference Figures 5 to 8 The etching method is explained.

[0118] Figure 5 This is a timing diagram showing the timing of gas supply from each of the supply units 21, 22, 23, 24, 25 and the timing of microwave oscillation by the ultrasonic discharge tube 26 of the microwave source 28.

[0119] like Figure 5 As shown, during the etching of substrate S, the control unit 10C first controls the driving of the NH3 gas supply unit 23, the N2 gas supply unit 21, and the HF gas supply unit 24 (at time t1). As a result, the NH3 gas supply unit 23 begins supplying NH3 gas, thus introducing NH3 gas into the NH3 gas inlet through the selected first candidate 31. Meanwhile, the HF gas supply unit 24 begins supplying HF gas, thus introducing HF gas into the HF gas inlet through the selected second candidate 32. Finally, the N2 gas supply unit 21 begins supplying N2 gas, thus introducing N2 gas into the N2 gas inlet 33.

[0120] After the supply of each gas continues continuously from time t1 until a predetermined period has elapsed, the control unit 10C controls the operation of the NH3 gas supply unit 23, the N2 gas supply unit 21, and the HF gas supply unit 24 (at time t2). As a result, the NH3 gas supply unit 23 stops supplying NH3 gas, thus stopping the introduction of NH3 gas. Similarly, the HF gas supply unit 24 stops supplying HF gas, thus stopping the introduction of HF gas. Finally, the N2 gas supply unit 21 stops supplying N2 gas, thus stopping the introduction of N2 gas.

[0121] After a predetermined period has elapsed from time t2, the control unit 10C controls the driving of the NH3 gas supply unit 22, the N2 gas supply unit 21, and the NF3 gas supply unit 25 (time t3). In the discharge tube 26, N2 gas and the excited NH3 gas are introduced into the processing chamber 11 through the N2 gas inlet 33.

[0122] Additionally, the NF3 gas supply unit 25 is connected to the gas dispersion tube 11C, thereby introducing NF3 gas into the processing chamber 11 through the NF3 gas inlet 34. Alternatively, the NF3 gas supply unit 25 is connected to the spray head 11D, thereby allowing at least one of the first candidate 31 and the second candidate 32 to be introduced into the processing chamber 11.

[0123] Therefore, the NH3 gas supply unit 22 begins supplying NH3 gas, and the N2 gas supply unit 21 supplies N2 gas, so the mixture of NH3 gas and N2 gas is supplied to the discharge tube 26. In addition, since the NF3 gas supply unit 25 begins supplying NF3 gas, NF3 gas is introduced from the gas inlet 34 of the gas dispersion tube 11C.

[0124] After a predetermined period from time t3, the control unit 10C controls the driving of the microwave source 28 (time t4). Since the microwave source 28 oscillates, the microwaves are irradiated by the discharge tube 26 through the waveguide 27, thereby generating plasma from the aforementioned mixed gas. The plasma generated from the mixed gas contains hydrogen radicals (H₂O₃), an example of excited-state matter. * Therefore, after time t4, H is introduced from the N2 gas inlet 33. * .

[0125] After a predetermined period has elapsed from time t4, control unit 10C controls the operation of NH3 gas supply unit 22, N2 gas supply unit 21, NF3 gas supply unit 25, and microwave source 28 (at time t5). As a result, NH3 gas supply unit 22 stops supplying NH3 gas, thus stopping the introduction of NH3 gas. Similarly, NF3 gas supply unit 25 stops supplying NF3 gas, thus stopping the introduction of NF3 gas. N2 gas supply unit 21 stops supplying N2 gas, thus stopping the introduction of N2 gas. Finally, microwave source 28 stops microwave oscillation.

[0126] Figures 6 to 8 The states of the first and second processed objects included in the substrate S are shown for each step in the etching method. It should be noted that... Figure 6 The state of substrate S at time t1 is shown. Figure 7 The state of substrate S at time t4 is shown, and Figure 8 The state of substrate S at time t5 is shown.

[0127] like Figure 6As shown, one example of substrate S includes a silicon nitride layer 51, a silicon layer 52, and a silicon oxide layer 53. Silicon layer 52 is an example of a first processing target, and silicon oxide layer 53 is an example of a second processing target. Silicon nitride layer 51 has a recess, and silicon layer 52 is located within the recess. Silicon oxide layer 53 is located on silicon layer 52. Silicon oxide layer 53 is, for example, a natural oxide film formed by exposing silicon layer 52 to the atmosphere. Silicon layer 52 is formed of polycrystalline silicon. In silicon layer 52, a modified silicon layer 52A is located on the surface adjacent to silicon oxide layer 53. Modified silicon layer 52A is not a layer formed of silicon oxide, but rather a portion modified by exposing silicon layer 52 to the atmosphere using oxygen from the atmosphere.

[0128] At time t1, NH3 gas and HF gas are introduced into the processing chamber 11. Thereby, within the processing chamber 11, a first etchant E1 is generated from the NH3 gas and HF gas. By supplying the first etchant E1 to the substrate S from time t1 to time t2, the silicon oxide layer 53 is etched. Therefore, the period from time t1 to time t2 constitutes the first step of etching the silicon oxide layer 53.

[0129] The etching method may include a change step, in which the distance between the center SC of the substrate S and the target aperture is changed by altering the position of the target aperture before the first step. This allows for a change in the distribution of the etching amount within the surface of the substrate S.

[0130] Furthermore, the etching method may include a setting step in which the flow rate of gas supplied by each of the multiple target ports is independently set before the first step. This allows the flow rate of gas supplied by each target port to be set. Therefore, the etching distribution within the surface of the substrate S can be changed by varying the flow rate of gas introduced through one target port, or by changing the ratio of the flow rate of gas supplied through the first target port to the flow rate of gas supplied through the second target port.

[0131] It should be noted that the setting process can change the flow rate of the gas introduced through each object port. Thus, the flow rate of the gas introduced through the object port can be changed without changing the total flow rate of the gas introduced into the processing chamber 11. Therefore, it is possible to change the gas distribution within the surface of the substrate S while suppressing pressure fluctuations within the processing chamber 11. This, in turn, allows for changes in the distribution of the etching amount within the surface of the substrate S.

[0132] like Figure 7 As shown, at time t4, excited-state matter and NF3 gas from a plasma generated by a mixture of NH3 and N2 gases are introduced into the processing chamber 11, thereby generating a second etchant E2 from the excited-state matter and NF3 gas. The modified silicon layer 52A is etched by supplying the second etchant E2 to the substrate S from time t4 to time t5.

[0133] like Figure 8 As a result, the modified silicon layer 52A is etched by supplying the second etchant E2 to the substrate S until time t5. Thus, the period from time t4 to time t5 is the second step of etching the modified silicon layer 52A, which is part of the silicon layer 52.

[0134] It should be noted that after time t5, the silicon-containing reaction product generated by the reaction of the second etchant E2 with the modified silicon layer 52A is located at least on the silicon layer 52. Therefore, by heating the substrate S, which has undergone the processing based on the first step and the processing based on the second step, using the first heating unit 11A, the reaction product on the silicon layer 52 evaporates.

[0135] [effect]

[0136] Reference Figures 9 to 12 The function of the etching method and etching apparatus is explained. Figure 9 The selectivity ratio of silicon oxide layer 53 to silicon layer 52 is shown. The selectivity ratio is the ratio of the amount of etching of silicon oxide layer 53 to the amount of etching of silicon layer 52. Figure 10 The selectivity ratio of silicon oxide layer 53 to silicon nitride layer 51 is shown. The selectivity ratio is the ratio of the amount of etching of silicon oxide layer 53 to the amount of etching of silicon nitride layer 51.

[0137] When using an excited-state material that is difficult to maintain in an activated state, the supply amount of the activated excited-state material deviates between multiple substrates S, thus causing deviations in the etching amount between substrates S. Regarding this, according to the first step of this disclosure, since NH3 gas and HF gas are used in the generation of the first etchant E1, the generation amount of the first etchant E1 between substrates S is less likely to deviate compared to the case where an excited-state material is used in the generation of the etchant. Therefore, deviations in the etching amount between substrates S can be suppressed.

[0138] Moreover, such as Figure 9 As shown, in an example of performing the first step under etching conditions, the selectivity of silicon oxide layer 53 to silicon layer 52 was confirmed to be 107.1 in the first step. In contrast, in an example of performing the second step under etching conditions, the selectivity of silicon oxide layer 53 to silicon layer 52 was confirmed to be 5.0 in the second step.

[0139] On the other hand, such as Figure 10As shown, in an example of performing the first step under etching conditions, the selectivity ratio of silicon oxide layer 53 to silicon nitride layer 51 was confirmed to be 52.5. In contrast, in an example of performing the second step under etching conditions, the selectivity ratio of silicon oxide layer 53 to silicon nitride layer 51 was confirmed to be 3.9.

[0140] Thus, regardless of whether the second etching target is silicon layer 52 or silicon nitride layer 51, the first process can achieve a higher selectivity than the second process for silicon oxide layer 53, which is the first processing target. Furthermore, the second process can also etch both the first and second processing targets.

[0141] Figure 11 The diagram shows the in-plane etching amount (E / A) distribution of substrate S in the first process. It should be noted that... Figure 11 In this process, a substrate with a radius of 150 mm and a silicon oxide layer of the same thickness was formed on the entire surface as the etching target. Figure 11 The etching amount is shown from the center of the substrate to a position 147 mm away in the radial direction from the substrate.

[0142] in addition, Figure 11 In this process, the distance between the NH3 gas inlet and the HF gas inlet, viewed from a perspective opposite to the plane extended by the substrate (i.e., the distance between the inlets), is changed to three distances: the first distance, the second distance, and the third distance. Among the first and third distances, the first distance is the shortest and the third distance is the longest. Figure 11 In the diagram, the etching amount when the inlet-to-inlet distance is set to the first distance is represented by a dashed line. The etching amount when the inlet-to-inlet distance is set to the second distance is represented by a solid line. The etching amount when the inlet-to-inlet distance is set to the third distance is represented by a single-dotted line. It should be noted that changing the inlet-to-inlet distance changes both the position of the NH3 gas inlet and the position of the HF gas inlet within the processing chamber 11.

[0143] like Figure 11 As shown, when the distance between the inlets is set to the first distance, it is confirmed that the etching amount is minimal at the center of the substrate, and the greater the distance from the center of the substrate, the greater the etching amount. Furthermore, it is confirmed that when the absolute values ​​of the distances from the center of the substrate are equal, the etching amounts are also equal. That is, when the distance between the inlets is set to the first distance, it is confirmed that the graph representing the relationship between the etching amount and the position on the substrate has a downward convex shape.

[0144] When the inlet-to-outlet distance is set to the second distance, it is confirmed that the etching amount is greatest at the center of the substrate, and the greater the distance from the center of the substrate, the smaller the etching amount. Furthermore, it is confirmed that when the absolute values ​​of the distances from the center of the substrate are equal, the etching amounts are also equal. That is, when the inlet-to-outlet distance is set to the second distance, it is confirmed that the graph representing the relationship between the etching amount and the position on the substrate has an upward convex shape.

[0145] When the inlet-to-outlet distance is set to the third distance, it is confirmed, similarly to the case where the inlet-to-outlet distance is set to the second distance, that the graph showing the relationship between the etching amount and the position on the substrate has an upward convex shape. It is confirmed that the maximum etching amount when the third distance is set is greater than the maximum etching amount when the second distance is set. Furthermore, it is confirmed that the minimum etching amount when the third distance is set is less than the minimum etching amount when the second distance is set.

[0146] In this way, the distribution of the etching amount in the surface of the substrate can be changed by altering the distance between at least one of the NH3 gas inlet and the HF gas inlet and the center of the substrate.

[0147] Figure 12 It is shown in relation to Figure 11 This graph shows the relationship between the distance between the inlet ports and the etching amount in six cases where only the distance between the inlet ports was changed during the same etching process. It should be noted that... Figure 12 The etching amount ratio is the ratio of the etching amount at the center of the substrate to the etching amount at a position 147 mm away from the center of the substrate. Therefore, when the etching amount ratio is less than 1, the graph showing the relationship between the etching amount and the position on the substrate shows a downward convex shape, while when the etching amount ratio is greater than 1, the graph showing the relationship between the etching amount and the position on the substrate shows an upward convex shape.

[0148] like Figure 12 As shown, in one example of etching conditions, it was confirmed that the etching amount ratio is less than 1 when the distance between the inlets is less than 25 mm. Conversely, it was confirmed that the etching amount ratio is greater than 1 when the distance between the inlets is greater than 30 mm. By changing the distance between the inlets, i.e., the distance between the inlets and the center of the substrate, the in-plane etching amount of the substrate can be adjusted.

[0149] As explained above, according to one embodiment of the etching method and etching apparatus, the following effects can be obtained.

[0150] (1) Since NH3 gas and HF gas are used to etch the first processed object in the first process, the amount of etching between the substrates S is less likely to be distributed compared with the case where plasma is used for etching in the first and second processes.

[0151] (2) By changing the distance between the object port and the center SC of the substrate S, the distribution of the etching amount in the plane of the substrate S can be changed.

[0152] (3) The flow rate of the gas supplied by each object port can be set. Therefore, by changing the flow rate of the gas introduced by one object port, or by changing the ratio of the flow rate of the gas supplied by the first object port to the flow rate of the gas supplied by the second object port, the etching distribution in the plane of the substrate S can be changed.

[0153] (4) By changing the flow rate of the gas introduced into the processing chamber 11 from the object port, the gas distribution within the surface of the substrate S can be changed. This allows for a change in the distribution of the etching amount within the surface of the substrate S. In particular, by pre-setting a predetermined conductivity in the branch gas flow path connected to each object port, the combination of gas flow rates supplied from each object port can be changed without having a flow control unit at all object ports.

[0154] (5) By using a moving mechanism to move the object port, the distance between the object port and the center SC of the substrate S can be changed, thereby changing the distribution of the etching amount in the plane of the substrate S.

[0155] (6) Since there is one supply unit 23, 24 for each target port, the degree of freedom in the combination of gas flow rates supplied by each target port can be increased.

[0156] It should be noted that the above implementation method can be modified as follows.

[0157] [Object Port]

[0158] In the etching apparatus 10, only one of the NH3 gas inlet and the HF gas inlet can be the target port. For example, when the NH3 gas inlet is the target port, the position of the HF gas inlet in the processing chamber 11 is fixed. Conversely, when the HF gas inlet is the target port, the position of the NH3 inlet in the processing chamber 11 is fixed.

[0159] The operation of changing the target port from the first candidate to the second candidate can be performed by the user of the etching apparatus 10. The change operation can be, for example, switching the opening and closing of the valve mentioned above, or switching the connection target of the NH3 gas supply unit 23 or the HF gas supply unit 24 from the first candidate to the second candidate.

[0160] [Flow Control Department]

[0161] As described above, when one NH3 gas supply unit 23 is connected to multiple pipes, and each pipe is connected to one first candidate 31, the multiple pipes include pipes with a first conductivity and pipes with a second conductivity. The first conductivity and the second conductivity are different. In this case, even if the set value in the NH3 gas supply unit 23 is the same, the flow rate of the NH3 gas can be changed by selecting either a pipe with the first conductivity or a pipe with the second conductivity, as the pipe supplying NH3 gas to the NH3 gas supply unit 23.

[0162] When one HF gas supply unit 24 is connected to multiple pipes, and each pipe is connected to one second candidate 32, the multiple pipes include pipes with a first conductivity and pipes with a second conductivity. The first conductivity and the second conductivity are different. In this case, even if the settings in the HF gas supply unit 24 are the same, the flow rate of the HF gas supplied by the HF gas supply unit 24 can be changed by selecting either a pipe with the first conductivity or a pipe with the second conductivity.

[0163] · Figure 4 In the process, in the branch flow paths that are respectively connected to multiple first candidates 31 ( Figure 4 In the example, there are 3 branch flow paths) and branch flow paths connected to multiple second candidates 32 respectively. Figure 4 In the example, there are 3 branch flow paths, each of which can have 1 mass flow controller (flow control unit).

[0164] [Mobile Agency]

[0165] ·like Figure 13 As shown, the etching apparatus 10 may include a first moving mechanism 41 and a second moving mechanism 42. The first moving mechanism 41 and the second moving mechanism 42 are disposed within the processing chamber 11, opposite to the exhaust section 11B. The first moving mechanism 41 includes a first rotating section 41A, a first nozzle 41B, and an NH3 gas inlet 41C. The rotating section 41A, the first nozzle 41B, and the NH3 gas inlet 41C are disposed within the processing chamber 11. The first rotating section 41A is configured to rotate about a rotation axis extending in a direction parallel to the extending direction of the processing chamber 11, i.e., it is rotatable. The first nozzle 41B is connected to the first rotating section 41A. The NH3 gas inlet 41C is located at the front end of the first nozzle 41B. The NH3 gas supply section 23 is connected to the first rotating section 41A. NH3 gas is supplied to the NH3 gas inlet 41C through the first rotating section 41A and the first nozzle 41B.

[0166] The second moving mechanism 42 includes a second rotating part 42A, a second nozzle 42B, and an HF gas inlet 42C. The second rotating part 42A, the second nozzle 42B, and the HF gas inlet 42C are disposed within the processing chamber 11. The second rotating part 42A is configured to rotate about a rotation axis extending in a direction parallel to the extending direction of the processing chamber 11, i.e., it is rotatably movable. The second nozzle 42B is connected to the second rotating part 42A. The HF gas inlet 42C is located at the front end of the second nozzle 42B. The HF gas supply part 24 is connected to the second rotating part 42A. HF gas is supplied to the HF gas inlet 42C through the second rotating part 42A and the second nozzle 42B.

[0167] NH3 gas inlet 41C is an example of the first gas inlet, and HF gas inlet 42C is an example of the second gas inlet. Both NH3 gas inlet 41C and HF gas inlet 42C are located on planes orthogonal to the normal to the substrate S. NH3 gas inlet 41C is configured such that the flow direction of NH3 gas introduced through NH3 gas inlet 41C is parallel to the plane extended by the substrate S. HF gas inlet 42C is configured such that the flow direction of HF gas introduced through HF gas inlet 42C is parallel to the plane extended by the substrate S and parallel to the flow direction of NH3 gas.

[0168] The distance between the NH3 gas inlet 41C and the HF gas inlet 42C can be changed by at least one of rotating the first rotating part 41A using the first moving mechanism 41 and rotating the second rotating part 42A using the second moving mechanism 42. Furthermore, rotating the first rotating part 41A using the first moving mechanism 41 changes the angle at which NH3 gas is introduced into the substrate S. Similarly, rotating the second rotating part 42A using the second moving mechanism 42 changes the angle at which HF gas is introduced into the substrate S.

[0169] Furthermore, by using the first moving mechanism 41 and rotating the first rotating part 41A, the distance between the NH3 gas inlet 41C and the center SC of the substrate S can be changed. By using the second moving mechanism 42 and rotating the second rotating part 42A, the distance between the HF gas inlet 42C and the center SC of the substrate S can be changed. By using the etching apparatus 10 and at least one of the first moving mechanism 41 and the second moving mechanism 42, the distribution of the etching amount within the surface of the substrate S can be changed.

[0170] It should be noted that the rotation amount of each rotating part 41A, 42A, that is, the position of the inlet port 41C, 42C in the processing chamber 11, can be changed by the control part 10C or by the user of the etching device 10.

[0171] [Step 1]

[0172] • In the first step, the entire silicon oxide layer 53 can be removed, or a portion of the silicon oxide layer 53 can remain on the substrate S. It should be noted that if a portion of the silicon oxide layer 53 remains on the substrate S in the first step, the portion of the silicon oxide layer 53 can be removed together with the silicon layer 52 or the silicon nitride layer 51 in the second step.

[0173] • The first step can also be performed after the second step.

[0174] Explanation of reference numerals in the attached figures

[0175] 10…Etching apparatus

[0176] 11…processing chamber

[0177] 21…N2 Gas Supply Department

[0178] 22,23…NH3 Gas Supply Department

[0179] 24…HF Gas Supply Department

[0180] 25…NF3 Gas Supply Department

[0181] 26…discharge tube

[0182] 27…waveguide

[0183] 28…microwave source

Claims

1. An etching method, wherein, The multiple substrates housed in the vacuum chamber each have a first processing object and a second processing object. The first processing target is a silicon oxide layer. The second processing target is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The etching method includes the following steps: In the first step, NH3 gas and HF gas are introduced into the vacuum chamber to etch the first object to be processed. as well as In the second step, after the first step, plasma generated from a gas containing NH3 and NF3 gas are supplied to the vacuum chamber, thereby etching the object to be processed in the second step. At least one of the NH3 gas inlet for introducing NH3 gas into the vacuum tank and the HF gas inlet for introducing HF gas into the vacuum tank is the target port. The etching method includes a change step, prior to the first step, in which the position of the object aperture is changed, thereby changing the distance between the center of the substrate and the object aperture.

2. An etching method, wherein, The multiple substrates housed in the vacuum chamber each have a first processing object and a second processing object. The first processing target is a silicon oxide layer. The second processing target is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The etching method includes the following steps: In the first step, NH3 gas and HF gas are introduced into the vacuum chamber to etch the first object to be processed. as well as In the second step, after the first step, plasma generated from a gas containing NH3 and NF3 gas are supplied to the vacuum chamber, thereby etching the object to be processed in the second step. Either the NH3 gas inlet for introducing NH3 gas into the substrate or the HF gas inlet for introducing HF gas into the substrate is designated as the target port. The etching method includes a setting step, prior to the first step, in which the flow rate of gas supplied by each of the plurality of object ports is independently set.

3. The etching method according to claim 2, wherein, In the setting process, the flow rate of the gas introduced through each of the object ports is changed by pre-setting the conductivity of the gas flow path of the gas introduced through the object port.

4. An etching apparatus, wherein, The substrate includes a first processing object and a second processing object. The first processing target is a silicon oxide layer. The second processing target is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The etching apparatus has the following features: A vacuum chamber for accommodating multiple substrates; The first processing unit introduces NH3 gas and HF gas into the vacuum chamber, thereby etching the first processing object; The second processing unit, after etching the first processing object, introduces plasma generated from a gas containing NH3 gas and NF3 gas into the vacuum chamber, thereby etching the second processing object; An NH3 gas inlet for introducing NH3 gas into the vacuum chamber; and The HF gas inlet is used to introduce HF gas into the vacuum chamber. At least one of the NH3 gas inlet and the HF gas inlet is the target port. The etching apparatus has multiple candidates for the object port. The distance between the center of the substrate and one of the candidates is different from the distance between the center and the other candidates.

5. An etching apparatus, wherein, The substrate includes a first processing object and a second processing object. The first processing target is a silicon oxide layer. The second processing target is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The etching apparatus has the following features: A vacuum chamber for accommodating multiple substrates; The first processing unit introduces NH3 gas and HF gas into the vacuum chamber, thereby etching the first processing object; The second processing unit, after etching the first processing object, introduces plasma generated from a gas containing NH3 gas and NF3 gas into the vacuum chamber, thereby etching the second processing object; An NH3 gas inlet for introducing NH3 gas into the vacuum chamber; and The HF gas inlet is used to introduce HF gas into the vacuum chamber. At least one of the NH3 gas inlet and the HF gas inlet is the target port. The etching apparatus further includes a moving mechanism to move the object port, thereby changing the distance between the center of the substrate and the object port.

6. An etching apparatus, wherein, The substrate includes a first processing object and a second processing object. The first processing target is a silicon oxide layer. The second processing target is a silicon nitride layer or a silicon layer covered by the silicon oxide layer. The etching apparatus has the following features: A vacuum chamber for accommodating multiple substrates; The first processing unit introduces NH3 gas and HF gas into the vacuum chamber, thereby etching the first processing object; The second processing unit is formed by a gas containing NH3 gas after the etching of the first processing object; An NH3 gas inlet for introducing NH3 gas into the vacuum chamber; and The HF gas inlet is used to introduce HF gas into the vacuum chamber. Either the NH3 gas inlet or the HF gas inlet is the target port. The etching apparatus has multiple object ports. The etching apparatus includes a flow control unit for each of the object ports, which controls the flow rate of the gas supplied from that object port.

7. The etching apparatus according to claim 6, wherein, The flow control unit controls the flow rate of the gas to maintain the total flow rate of the gas introduced through all the target ports and to change the flow rate of the gas introduced through each of the target ports.

8. An etching apparatus comprising: A vacuum chamber for accommodating multiple substrates; The first gas inlet for introducing NH3 gas into the vacuum chamber; The second gas inlet for introducing HF gas into the vacuum chamber; A mechanism for changing the distance between the first gas inlet and the second gas inlet; The third gas inlet for introducing NF3 gas; and The fourth gas inlet is used to introduce NH3 gas after it has been discharged through the discharge tube.

9. The etching apparatus according to claim 8, wherein, The first gas inlet and the second gas inlet are arranged such that, by being positioned on a plane orthogonal to the normal of the substrate, the gases introduced through the first gas inlet and the second gas inlet respectively flow parallel to the substrate and parallel to each other. The etching apparatus includes a mechanism for rotating and moving the first gas inlet and the second gas inlet around an axis parallel to the normal of the substrate disposed in the vacuum chamber.

10. An etching apparatus comprising: A vacuum chamber for accommodating multiple substrates; The first gas inlet for introducing NH3 gas into the vacuum chamber; A second gas inlet for introducing HF gas into the vacuum chamber; and A mechanism for changing the distance between the first gas inlet and the second gas inlet. NH3 gas introduced through one flow path is branched into two or more of the first gas inlets, and HF gas introduced through one flow path is branched into two or more of the second gas inlets. The etching apparatus includes a mechanism that, by selecting branches of NH3 gas and HF gas, changes the distance between the target port of the NH3 gas inlet selected from the two or more first gas inlets and the target port of the HF gas inlet selected from the two or more second gas inlets.

11. The etching apparatus according to claim 10, wherein, The NH3 gas introduced through one flow path is branched into flow paths with different conductivity, and, The HF gas introduced from one flow path is branched into flow paths with different conductivity.

12. An etching apparatus comprising: A vacuum chamber for accommodating multiple substrates; The first gas inlet for introducing NH3 gas into the vacuum chamber; A second gas inlet for introducing HF gas into the vacuum chamber; and A mechanism for changing the distance between the first gas inlet and the second gas inlet. NH3 gas introduced through one flow path is branched into two or more of the first gas inlets, and HF gas introduced through one flow path is branched into two or more of the second gas inlets. Each branch flow path has its own flow control unit.

13. An etching method comprising the following treatment of a plurality of substrates housed in a vacuum chamber: The first process, performed by introducing NH3 gas and HF gas into the vacuum chamber, and The second process is performed by supplying plasma generated from a gas containing NH3 gas and NF3 gas to the vacuum chamber. In the first process, NH3 gas introduced through one flow path is branched into two or more first gas inlets, and HF gas introduced through one flow path is branched into two or more second gas inlets. By selecting the branches of NH3 gas and HF gas, the distance between the target port of the NH3 gas inlet selected from the two or more first gas inlets and the target port of the HF gas inlet selected from the two or more second gas inlets is changed.

14. The etching method according to claim 13, wherein, The first process targets a silicon oxide layer. The object of the second treatment is a silicon nitride layer or a silicon layer covered by the silicon oxide layer.

15. The etching method according to claim 14, wherein, The second process is performed after the first process.

16. The etching method according to claim 13, wherein, The NH3 gas introduced through one flow path is branched into flow paths with different conductivity, and the HF gas introduced through one flow path is also branched into flow paths with different conductivity. NH3 gas and HF gas are introduced at different flow rates through the target ports of the NH3 gas inlet and the HF gas inlet, respectively.

17. An etching method comprising the following treatment of a plurality of substrates housed in a vacuum chamber: The first process, performed by introducing NH3 gas and HF gas into the vacuum chamber, and The second process is performed by supplying plasma generated from a gas containing NH3 gas and NF3 gas to the vacuum chamber. In the first process, NH3 gas introduced through one flow path is branched into two or more first gas inlets, and HF gas introduced through one flow path is branched into two or more second gas inlets. By selecting the branches of NH3 gas and HF gas, the distance between the target port of the NH3 gas inlet selected from the two or more first gas inlets and the target port of the HF gas inlet selected from the two or more second gas inlets is changed. Each branch of the flow path is equipped with a flow control unit, which introduces NH3 gas and HF gas at different flow rates through the target ports of the NH3 gas inlet and the target ports of the HF gas inlet.

18. An etching method comprising the following treatment of a plurality of substrates housed in a vacuum chamber: The first process, performed by introducing NH3 gas and HF gas into the vacuum chamber, and The second process is performed by supplying plasma generated from a gas containing NH3 gas and NF3 gas to the vacuum chamber. In the first process, NH3 gas is introduced through the first gas inlet, and HF gas is introduced through the second gas inlet. The first gas inlet and the second gas inlet are arranged such that, by being positioned on a plane orthogonal to the normal of the substrate, the gases introduced through the first gas inlet and the second gas inlet respectively flow parallel to the substrate and parallel to each other. By rotating and moving the first gas inlet and the second gas inlet around an axis parallel to the normal of the substrate disposed in the vacuum chamber, the distance between the first gas inlet and the second gas inlet, as well as the introduction angle of NH3 gas and the introduction angle of HF gas, are changed.

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