KR20230072429A - Etching method and etching device - Google Patents

Abstract

Provided is an etching method and an etching device which can make it possible to suppress the distribution of an etching amount between substrates, wherein a plurality of substrates accommodated in a vacuum chamber have a first processing target and a second processing target respectively. The first processing target is a silicon oxide layer (53) and the second processing target is a silicon layer (52) covered by a silicon nitride layer (51) or the silicon oxide layer (53). The etching method of the present invention includes: a first process of etching the first processing target by introducing NH_3 gas and HF gas into the vacuum chamber; and a second process of etching the second processing target by supplying plasma generated from a gas containing NH_3 gas and NF_3 gas to the vacuum chamber after the first process.

Description

Etching method and etching device {ETCHING METHOD AND ETCHING DEVICE}

The present invention relates to an etching method and an etching apparatus.

[0002] An oxide film removal device is known that removes a native oxide film formed on the surface of a silicon substrate by etching. An oxide film removal device generates an etchant for a natural oxide film using radicals included in plasma generated using microwaves, and converts the native oxide film into a complex containing silicon by the generated etchant. The thermal decomposition temperature of the complex is lower than that of the native oxide film. Further, the oxide film removing device vaporizes the complex from the silicon substrate by heating the silicon substrate together with the complex. By this, the oxide film removing device removes the native oxide film from the silicon substrate. The oxide film removal device is capable of processing a plurality of silicon substrates at one time (see Patent Document 1, for example).

It is also known that etching can be performed similarly to the oxide film removal device without using plasma generated using microwaves. By changing the type of gas used for etching, the oxide film can be removed without using plasma.

Patent Document 1: International Patent Publication No. 2012/002393

By the way, in the case of a batch type apparatus that processes a plurality of substrates at the same time, a plurality of gases for generating an etchant are blown from the outer periphery of the substrates within the treatment tank of the apparatus. Since the etchant emitted from the outer periphery performs an etching reaction and is consumed on the surface of the substrate while proceeding to the exhaust provided in the treatment tank, a distribution occurs in the concentration of the etchant under treatment in the treatment tank according to the consumed amount. As a result, a distribution is also generated in the etching rate of the substrate surface, and a distribution is generated in the target etching amount.

In addition, this problem occurs even when a substrate to be etched includes a silicon nitride layer as well as a silicon oxide layer. It is also known that the larger the surface area of the object to be treated, the larger the effect.

Also, in etching using plasma, radicals used to generate an etchant lose their excited state due to collision with other gases or the walls of the induced radical guide tube or dispersion mechanism. For this reason, among a plurality of silicon substrates, a distribution occurs in the arrival amount of excited radicals between the silicon substrates depending on the shape of the radical guiding tube in the oxide film removal device or the dispersing mechanism. As a result, the etching amount of the oxide film also has a distribution among the silicon substrates.

In an etching method for solving the above problems, a plurality of substrates accommodated in a vacuum chamber each have a first processing target and a second processing target, the first processing target is a silicon oxide layer, and the second processing target is a silicon oxide layer. a silicon layer covered with a nitride layer or the silicon oxide layer, and a first step of etching the first processing target by introducing NH ₃ gas and HF gas into the vacuum chamber; and, after the first step, NH ₃ gas and a second step of etching the second processing object by supplying plasma generated from a gas containing NF ₃ gas to the vacuum chamber.

According to the above etching method, since etching of the first processing target is performed using NH ₃ gas and HF gas in the first step, etching is performed using plasma in both the first step and the second step. Compared to the case, it is difficult to produce a distribution in the etching amount between the substrates.

In the etching method, at least one of an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber is a target hole, and prior to the first step, the target A changing step of changing the distance between the center of the substrate and the target sphere by changing the position of the sphere may be included. According to this etching method, it is possible to change the distribution of the etching amount within the plane of the substrate by changing the distance between the target sphere and the center of the substrate.

In the etching method, either one of the NH _{3 gas inlet for introducing NH 3 gas} into the substrate and the HF gas inlet for introducing HF gas into the substrate is a target hole, and prior to the first step, a plurality of In the target sphere, a setting step of independently setting the flow rate of gas supplied from each target sphere may be included.

According to the above etching method, since it is possible to set the flow rate of gas supplied from each target sphere, it is possible to change the flow rate of gas introduced from one target sphere, or to change the flow rate of gas supplied from the first target sphere. It is possible to change the distribution of etching within the surface of the substrate by changing the flow rate ratio of the gas supplied from the two target spheres.

In the etching method, in the setting step, the total flow rate of the gas to be introduced in all of the target spheres may be maintained, and the flow rate of the gas introduced in each of the target spheres may be changed. According to this etching method, since the flow rate of the gas introduced from the target port is changed without changing the total flow rate of the gas introduced into the vacuum chamber, the distribution of the gas within the surface of the substrate is controlled while suppressing the pressure fluctuation in the vacuum chamber. it is possible to change This makes it possible to change the distribution of the etching amount within the surface of the substrate.

In an etching apparatus for solving the above problems, a substrate includes a first processing target and a second processing target, the first processing target is a silicon oxide layer, and the second processing target is a silicon nitride layer or the silicon oxide layer. A silicon layer covered with a vacuum chamber for accommodating a plurality of the substrates, a first processing unit for etching the first processing target by introducing NH ₃ gas and HF gas into the vacuum chamber, and after etching the first processing target and a second processing unit for etching the second processing target by introducing plasma generated from a gas containing NH ₃ gas and NF ₃ gas into the vacuum chamber.

According to the etching apparatus, since the first processing unit performs etching of the first processing target using NH ₃ gas and HF gas, when both the first processing unit and the second processing unit perform etching using plasma, In contrast, it is difficult to produce a distribution in the etching amount between the substrates.

In the etching apparatus, an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber, at least one of the NH ₃ gas inlet and the HF gas inlet is a target sphere, and the etching apparatus includes a plurality of candidates for the target sphere, and the distance between the center of the substrate and one of the candidates may be different from the distance between the center and the other candidates.

Since the etching apparatus has a plurality of target ball candidates, it is possible to change the distance between the target ball and the center of the substrate between a case where the first candidate is selected as the target ball and a case where the second candidate is selected as the target ball. In this way, it is possible to change the distribution of the etching amount within the plane of the substrate between the case where the first candidate is selected as the target sphere and the case where the second candidate is selected as the target sphere.

In the etching apparatus, an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber are provided, and at least one of the NH ₃ gas inlet and the HF gas inlet is provided. is a target sphere, and the etching apparatus may further include a moving mechanism for moving the target sphere to change a distance between the center of the substrate and the target sphere.

According to the above etching device, the distance between the target sphere and the center of the substrate can be changed by the moving mechanism moving the target sphere, thereby changing the distribution of the etching amount within the surface of the substrate.

In the etching apparatus, an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber and an HF gas inlet for introducing HF gas into the vacuum chamber are provided, and either the NH ₃ gas inlet or the HF gas inlet is provided. is a target sphere, the etching device includes a plurality of the target spheres, and the etching device may include one flow rate controller for controlling a flow rate of gas supplied from the corresponding target sphere for each of the target spheres. According to such an etching apparatus, since one flow rate controller is provided for one target sphere, it is possible to increase the degree of freedom in the combination of flow rates of gas supplied from each target sphere.

In the above etching device, the flow rate controller may control the flow rate of the gas so as to maintain a total flow rate of the gas introduced from all of the target spheres and change the flow rate of the gas introduced from each of the target spheres.

According to the above etching device, since the flow rate controller changes the flow rate of the gas introduced from the target hole without changing the total flow rate of the gas, it is possible to change the distribution of the gas within the surface of the substrate while suppressing the fluctuation of the pressure in the vacuum chamber. possible. This makes it possible to change the distribution of the etching amount within the surface of the substrate.

An etching apparatus for solving the above problems includes a vacuum chamber for accommodating a plurality of substrates, a first gas inlet for introducing NH ₃ gas into the vacuum chamber, and a 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.

According to the above etching apparatus, since the distance between the first gas inlet for introducing NH ₃ gas and the second gas inlet for introducing HF can be changed, an etchant for etching the silicon oxide layer can be synthesized in a vacuum chamber. Since the position can be changed, the etching distribution within the substrate surface can be adjusted.

In the above etching device, a third gas inlet for introducing the NF ₃ gas and a fourth gas inlet for introducing the NH ₃ gas discharged through the discharge tube may be provided.

According to the above etching apparatus, it is possible to combine etching using plasma with respect to the silicon nitride layer or the silicon layer, which is not etched by etching using no plasma, and the degree of freedom in the etching selectivity of the silicon nitride film layer or the silicon layer can be increased. there is.

In the etching apparatus, NH ₃ gas introduced from one passage is branched into two or more first gas inlets, and HF gas introduced from one passage is branched into two or more second gas inlets; , by selecting branches of the NH ₃ gas and the HF gas, between the target port of the NH ₃ gas inlet selected from the two or more first gas inlets and the HF gas inlet selected from the two or more second gas inlets A mechanism for changing the distance may be provided.

According to the above etching apparatus, since the distance between the first gas inlet for introducing NH ₃ gas and the second gas inlet for introducing HF can be changed, an etchant for etching the silicon oxide layer can be synthesized in a vacuum chamber. Since the position can be changed, the etching distribution within the substrate surface can be adjusted.

In the above etching apparatus, NH ₃ gas introduced from one flow path may branch to flow paths having different conductances, and HF gas introduced from one flow path may branch into flow paths having different conductances.

According to the above etching device, not only the position of the etchant depending on the distance of the inlet but also the distribution of the gas for generating the etchant can be adjusted in advance, so that the etching distribution within the surface of the substrate can be adjusted with a degree of freedom.

In the etching apparatus, NH ₃ gas introduced from one passage is branched into two or more first gas inlets, and HF gas introduced from one passage is branched into two or more second gas inlets; , the branched passages may each have one flow rate controller.

According to the above etching device, by having one flow rate controller at each inlet, it is possible to adjust the distribution of gas for generating a finer etchant, and it is possible to have a degree of freedom in adjusting the distribution within the surface of the substrate.

In the etching apparatus, the first gas inlet and the second gas inlet are arranged on a plane orthogonal to the normal line of the substrate, so that the gas introduced from the first gas inlet and the second gas inlet, respectively, A mechanism provided so as to flow parallel to the substrate and parallel to each other, and to rotate and move the first gas inlet and the second gas inlet around an axis parallel to the normal line of the substrate installed in the vacuum chamber. You can do it.

According to the above etching device, it is possible to continuously set the positional relationship and angle of the inlet, and it is possible to finely change the position where the etchant is synthesized in the vacuum chamber.

An etching method for solving the above problems includes a first process performed by introducing NH ₃ gas and HF gas into the vacuum chamber for a plurality of substrates accommodated in the vacuum chamber, and a gas generated from the gas containing the NH ₃ gas and a second process performed by supplying plasma and NF ₃ gas to the vacuum chamber.

In the etching method, the subject of the first process may be a silicon oxide layer, and the subject of the second process may be a silicon nitride layer or a silicon layer covered by the silicon oxide layer.

According to the above etching method, it is possible to combine etching using plasma with respect to the silicon nitride layer or the silicon layer, which is not etched in the etching using no plasma, and the degree of freedom in the etching selectivity of the silicon nitride film layer or the silicon layer can be increased. there is.

In the above etching method, the second treatment may be performed after the first treatment.

According to the above etching method, the first process does not receive the etching distribution caused by the radicals received in the first process.

In the above etching method, in the first processing, the NH ₃ gas introduced from one flow path is branched to two or more of the first gas introduction ports, and the HF gas introduced from one flow path is branched into two or more of the second gas inlets. It is branched into a gas inlet, and by selecting a branch of NH ₃ gas and HF gas, the object of the NH ₃ gas inlet selected from the two or more first gas inlets and the HF gas selected from the two or more second gas inlets The distance between target balls of the inlet may be changed.

According to the above etching method, since the distance between the first gas inlet for introducing NH ₃ gas and the second gas inlet for introducing HF can be changed, an etchant for etching the silicon oxide layer is synthesized in a vacuum chamber. Since the position can be changed, the etching distribution within the substrate surface can be adjusted.

In the etching method, the NH ₃ gas introduced from one passage is branched into a passage having a different conductance, the HF gas introduced from the one passage is branched into a passage having a different conductance, and the NH ₃ gas and HF Gas may be introduced from the target port of the NH ₃ gas inlet and the target port of the HF gas inlet at different flow rates.

According to the above etching method, since not only the position of the etchant by the distance of the inlet but also the distribution of the gas for generating the etchant can be adjusted in advance, it is possible to have a degree of freedom in adjusting the etching distribution within the substrate surface.

In the etching method, in the first processing, the NH ₃ gas introduced from one passage is branched to two or more first gas introduction ports, and the HF gas introduced from one passage is divided into two or more second gases. It is branched into the inlet, and by selecting a branch of the NH ₃ gas and the HF gas, the target port of the NH ₃ gas inlet selected from the two or more first gas inlets and the HF gas selected from the two or more second gas inlets are introduced The distance between spheres and target spheres may be varied. In addition, the NH ₃ gas and the HF gas may be introduced from the target opening of the NH ₃ gas inlet and the target opening of the HF gas inlet at different flow rates by flow rate controllers, each provided in each of the branched passages.

According to the above etching method, since the distribution of the gas for generating the etchant can be further finely adjusted in advance, it is possible to have a degree of freedom in adjusting the etching distribution within the surface of the substrate.

In the etching method, in the first process, NH ₃ gas is introduced from the first gas inlet and HF gas is introduced from the second gas inlet at the same time, and the first gas inlet and the second gas inlet are connected to the substrate By being disposed on a plane orthogonal to the normal line of , the gas introduced from the first gas inlet and the second gas inlet may flow parallel to the substrate and parallel to each other. Furthermore, by rotating the first gas inlet and the second gas inlet around an axis parallel to the normal line of the substrate installed in the vacuum chamber, the first gas inlet and the second gas inlet are moved. The introduction angle of the NH ₃ gas and the introduction angle of the HF gas may be changed simultaneously with changing the distance.

According to the above etching method, it is possible to continuously set the positional relationship and angle of the inlet, and it is possible to change the position where the etchant is synthesized in the vacuum chamber more finely.

according to the present invention. Distribution of the etching amount between substrates can be suppressed.

1 is a device configuration diagram showing the configuration of an etching device in one embodiment.
FIG. 2 is a device configuration diagram showing the configuration of a processing chamber (processing chamber) included in the etching apparatus shown in FIG. 1 .
FIG. 3 is a schematic view showing candidates for NH ₃ gas inlets and HF gas inlets provided in the processing chamber shown in FIG. 2 .
4 is a schematic diagram showing the relationship between NH ₃ gas inlet candidates and HF gas inlet candidates and a substrate.
5 is a timing chart for explaining an etching method in one embodiment.
6 is a process chart showing one step in the etching method.
7 is a process chart showing one step in the etching method.
8 is a process chart showing one step in the etching method.
9 is a graph showing the selectivity of a silicon oxide layer with respect to a silicon layer.
10 is a graph showing the selectivity of a silicon nitride layer with respect to a silicon layer.
11 is a graph showing the relationship between the position on the substrate and the etching amount.
12 is a graph showing the relationship between the ratio of the distance between introduction sections and the amount of etching.
Fig. 13 is a schematic diagram showing candidates for NH ₃ gas inlets and candidates for HF gas inlets in a modified example of an etching apparatus.

1 to 12, an embodiment of an etching method and an etching apparatus will be described.

etching device

Referring to Figs. 1 to 4, the etching apparatus will be described.

The etching apparatus 10 shown in FIG. 1 is configured to be capable of simultaneously etching a plurality of substrates. The substrate has a first processing target and a second processing target. The first processing target is a silicon oxide layer. The second processing object is a silicon layer covered with a silicon nitride layer or a silicon oxide layer as a first processing object.

The etching apparatus 10 includes a processing chamber 11 and a carry-in/out chamber (carry-in/out chamber) 12 . The processing chamber 11 is an example of a vacuum chamber for accommodating substrates. In the processing chamber 11, etching of the substrate is performed. In the carry-in/out chamber 12 , substrates before the etching process in the processing chamber 11 are carried in from the outside of the carry-in/out chamber 12 , and substrates after the etching process are carried out of the carry-in/out chamber 12 .

A gate valve 13 is positioned between the processing chamber 11 and the carry-in/out chamber 12 . The gate valve 13 has an open state and a closed state. When the gate valve 13 is opened, the space defined by the processing chamber 11 is connected to the space defined by the carry-in/out chamber 12 . In contrast, when the gate valve 13 is closed, the space defined by the processing chamber 11 moves away from the space defined by the carry-in/out chamber 12 .

The processing chamber 11 includes a first heating unit 11A and an exhaust unit 11B. The first heating unit 11A simultaneously heats a plurality of substrates located in the processing chamber 11 . The first heating unit 11A adjusts the temperature of the substrate positioned in the space to a predetermined substrate temperature by, for example, adjusting the temperature of the space defined by the processing chamber 11 to a predetermined chamber temperature. The chamber temperature and the substrate temperature may be the same temperature or different temperatures. The exhaust unit 11B depressurizes the inside of the processing chamber 11 to a predetermined pressure.

The etching apparatus 10 includes a nitrogen (N ₂ ) gas supply unit 21, an ammonia (NH ₃ ) gas supply unit 22, 23, a hydrogen fluoride (HF) gas supply unit 24, and a nitrogen trifluoride (NF ₃ ) gas A supply unit 25 is provided. NH ₃ gas, HF gas, and NF ₃ gas are gases for generating an etchant for etching a substrate, and N ₂ gas is a carrier gas supplied to a supplier together with NH ₃ gas, HF gas, and NF ₃ gas.

Each supply part 21, 22, 23, 24, 25 is a mass flow controller, for example, and is connected to the cylinder which stores the gas supplied by each supply part 21, 22, 23, 24, 25. A mass flow controller is an example of a flow control unit. A valve is located between each supply part 21, 22, 23, 24, 25 and the supply part of the supply part 21, 22, 23, 24, 25. When the valve is opened, the gas supplied from the respective supply units 21, 22, 23, 24 and 25 flows into the supply source. In contrast, when the valve is closed, the gas supplied from the respective supply units 21, 22, 23, 24, and 25 does not flow into the supply source.

Etching device 10 includes a discharge tube 26, a wave guide 27 and a microwave source 28. The microwave generated by the microwave source 28 is irradiated to the discharge tube 26 through the waveguide 27 . Of the supply units 21 , 22 , 23 , 24 , and 25 described above, the NH ₃ gas supply unit 22 and the N ₂ gas supply unit 21 are connected to the discharge tube 26 . In a state where the NH ₃ gas and the N ₂ gas are supplied to the discharge tube 26, the discharge tube 26 is irradiated with microwaves, thereby exciting the NH ₃ gas and the N ₂ gas. That is, plasma is generated from a mixed gas of NH ₃ gas and N ₂ gas. By excitation of the mixed gas, H ^* , NH ^* , NH ₂ ^* and N ₂ ^* are generated.

The N ₂ gas supply unit 21 and the NH ₃ gas supply unit 22 are connected to the discharge tube 26 through a single pipe.

The NH ₃ gas supply unit 23 , the HF gas supply unit 24 and the NF ₃ gas supply unit 25 are connected to the processing chamber 11 . The NH ₃ gas supply unit 23 , the HF gas supply unit 24 and the NF ₃ gas supply unit 25 are connected to the processing chamber 11 through separate pipes.

12 A of vent gas supply parts are connected to the carry-in/out chamber 12. The vent gas supply unit 12A supplies a vent gas for cooling the substrate after etching into the carry-in/out chamber 12 . The gas for venting may be, for example, N ₂ gas. 12 A of gas supply parts for vents are mass flow controllers, for example, and are connected to the cylinder which stores the gas for vents.

The etching apparatus 10 further includes a control unit 10C. The control unit 10C controls driving of each unit included in the etching apparatus 10 . In this way, the control unit 10C enables etching of the first processing target and the second processing target by the etching apparatus 10 .

The control unit 10C has a storage unit 10CM. A process recipe is stored in the storage unit 10CM. The process recipe includes a plurality of process steps constituting the process recipe. The process recipe includes setting values related to the operation of the processing chamber 11, the carry-in/out room 12, and each unit connected to the processing chamber 11 in each process step. After reading the process recipe, the control unit 10C reads the setting values set for each process step for each process step, and generates a command according to the read setting values.

The control unit 10C controls driving of the NH ₃ gas supply unit 23 and the HF gas supply unit 24 , thereby introducing the NH ₃ gas and the HF gas into the processing chamber 11 . The control unit 10C then controls the driving of the NH ₃ gas supply unit 22, the NF ₃ gas supply unit 25, and the microwave source 28, whereby the plasma generated from the gas containing the NH ₃ gas and the NF ₃ Gas is supplied to the processing chamber 11 . Accordingly, the control unit 10C executes the first process, ie, the first process, and the second process, ie, the second process, included in the etching method performed in the etching device 10.

Thus, in the etching apparatus 10 of this embodiment, one example of the first processing unit includes the NH ₃ gas supply unit 23 and the HF gas supply unit 24 . An example of the second processing unit includes an NH ₃ gas supply unit 22 , an NF ₃ gas supply unit 25 , a discharge tube 26 , a waveguide 27 and a microwave source 28 .

2 shows the structure of the treatment chamber 11 . In addition, in FIG. 2 , illustration of the first heating unit 11A is omitted for convenience in describing functional units other than the first heating unit 11A provided in the processing chamber 11 .

As shown in FIG. 2, the etching apparatus 10 is equipped with the support part 10A which supports the board|substrate S. The support portion 10A supports a plurality of substrates S in an overlapped state with a gap G between the substrates S. In FIG. 2 , the support part 10A is located in the process chamber 11, but the etching device 10 is provided with a mechanism capable of moving the support part 10A between the carry-in/out chamber 12 and the process chamber 11. . In this way, the etching device 10 moves the support portion 10A from the carry-in/out chamber 12 to the processing chamber 11 or from the processing chamber 11 to the carrying-in/out chamber 12 in a state where the gate valve 13 is open. move

The substrate S has a circular shape, for example. As described above, the substrate S has a first processing target and a second processing target. When the second processing target is a silicon layer, the second processing target is formed of polysilicon. In this case, the first processing target is an oxide of polysilicon. The plurality of substrates S is supported by the support portion 10A with a gap G in the direction in which the plurality of substrates S overlap each other. The gap G is 5 mm or more and 20 mm or less, for example.

A gas dispersion pipe 11C is located in 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 .

In the processing chamber 11, a shower head 11D separate from the gas dispersion pipe 11C is attached. The shower head 11D has an inlet. Since the inlet of the shower 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 shower head 11D.

An NH ₃ gas supply unit 22 is connected to the shower head 11D via a discharge tube 26 . Further, the NF ₃ gas supply unit 25 is connected to the gas dispersion tube 11C without passing through the discharge tube 26 and the shower head 11D.

The NH ₃ gas supply unit 23, the HF gas supply unit 24, and the NF ₃ gas supply unit 25 are connected to separate pipes, respectively, and the NH ₃ gas supply unit 23 and the HF gas supply unit 24 are discharge tubes 26 ) and is connected to the shower head 11D.

The treatment chamber 11 includes a rotation unit 11E. The rotation unit 11E is configured to be connected to the support unit 10A when the support unit 10A is located in the processing chamber 11 . The rotation part 11E rotates the support part 10A with the central axis of the support part 10A as a rotation axis in the state connected to the support part 10A. The rotating portion 11E rotates the support portion 10A from the start to the end of etching for the first processing target and the second processing target. Thereby, in the board|substrate S, the etching amount at the predetermined position in the radial direction of the board|substrate S is substantially constant in the circumferential direction of the board|substrate S.

3 schematically shows inlets for introducing various gases into the processing chamber 11 . 3 schematically shows a plurality of gas introduction ports corresponding to one substrate S.

The etching apparatus 10 includes an NH ₃ gas inlet for introducing NH ₃ gas into the process chamber 11 and an HF gas inlet for introducing HF gas into the process chamber 11 . At least one of the NH ₃ gas inlet and the HF gas inlet is a target port. The NH ₃ gas inlet is an example of the first gas inlet, and the HF gas inlet is an example of the second gas inlet. The etching apparatus 10 has a plurality of candidates for target spheres. The distance between the center SC of the substrate S and one candidate is different from the distance between the center SC of the substrate S and another candidate.

Since the etching apparatus 10 of the present embodiment includes a plurality of target ball candidates, it is necessary to change the distance between the target ball and the center of the substrate between the case where the first candidate is selected as the target ball and the case where the second candidate is selected as the target ball. possible. In this way, it is possible to change the distribution of the etching amount within the surface of the substrate between the case where the first candidate is selected as the target sphere and the case where the second candidate is selected as the target sphere.

In the example shown in FIG. 3 , both the NH ₃ gas inlet and the HF gas inlet are target ports. The etching apparatus 10 includes a plurality of first candidates 31 as NH ₃ gas inlet candidates, and a plurality of second candidates 32 as HF gas inlet candidates. Each first candidate 31 is a hole for introducing NH ₃ gas into the processing chamber 11 and is a hole formed in the shower head 11D. Each second candidate 32 is a hole for introducing HF gas into the processing chamber 11 and is a hole formed in the shower head 11D. In Fig. 3, for convenience of illustration, illustration of the shower head 11D is omitted, and each of the candidates 31 and 32 is schematically shown.

In this embodiment, the etching apparatus 10 includes a first candidate group and a second candidate group. In the first candidate group, the first first candidate 31, the second first candidate 31, and the third first candidate 31 are sequentially arranged along one direction. The NH ₃ gas supply unit 23 is connected to the first candidate group. In the example of FIG. 3 , the flow path for supplying NH ₃ gas to the first candidate 31 is branched from one flow path to which the NH ₃ gas supply unit 23 is connected to three flow paths, and each flow path after divergence is one second flow path. It is connected to 1 candidate 31. The HF gas supply unit 24 is connected to the second candidate group. The flow path for supplying HF gas to the second candidate 32 is branched from one flow path to which the HF gas supply unit 24 is connected to three flow paths, and each flow path after branching is connected to one second candidate 32 has been

In a plane parallel to the plane on which the substrate S is enlarged, the distance between the first first candidate 31 and the first second candidate 32 is the first distance L1, and the third first candidate 31 The distance between the candidate 31 and the first second candidate 32 is a second distance L2. The first distance L1 is different from the second distance L2. In this embodiment, the first distance L1 is longer than the second distance L2.

In this embodiment, the first candidate 31 located at the leftmost position in FIG. 3 from the first candidate group is selected as the NH ₃ gas inlet, and the second candidate 32 located at the leftmost position in FIG. 3 among the second candidate group is selected as the HF gas inlet. NH ₃ gas is supplied into the process chamber 11 from the NH ₃ gas inlet, and HF gas is supplied into the process chamber 11 from the HF gas inlet.

When viewed from the viewpoint facing the plane on which the substrate S is enlarged, the exhaust unit 11B faces the first candidate 31 and the second candidate 32 . As a result, the substrate S is disposed between the first candidate 31 and the second candidate 32 and the exhaust unit 11B. As a result, the NH ₃ gas introduced into the processing chamber 11 through the NH ₃ gas inlet flows through the substrate S toward the exhaust unit 11B, and the HF gas introduced into the processing chamber 11 through the HF gas inlet It flows toward the exhaust part 11B through the substrate S.

In addition, the etching apparatus 10 includes an N ₂ gas inlet 33 and an NF ₃ gas inlet 34 . An N ₂ gas supply unit 21 is connected to the N ₂ gas inlet 33 . An NH ₃ gas supply unit 22 is connected to the N ₂ gas inlet 33 together with a N ₂ gas supply unit 21 . In this embodiment, the N ₂ gas inlet 33 is located between the first candidate group and the second candidate group. An NF ₃ gas supply unit 25 is connected to the NF ₃ gas inlet 34 . In this embodiment, the NF ₃ gas inlet 34 is disposed at a position away from the first candidate group, the second candidate group, and the N ₂ gas inlet 33 . The NF ₃ gas inlet 34 is an example of a third gas inlet, and the N ₂ gas inlet 33 is an example of a fourth gas inlet.

4 shows a plurality of substrates S supported by the support portion 10A and a relationship between each substrate S and the gas inlet. In addition, hereinafter, a method of setting a distance between a target sphere of NH ₃ gas selected from the first candidate group and a target sphere of HF gas selected from the second candidate group will be described.

As shown in FIG. 4 , the etching apparatus 10 includes the above-described first candidate group (ie, a plurality of first candidates 31), second candidate group (ie, a plurality of second candidates 32), and N ₂ gas. An inlet 33 and an NF ₃ gas inlet 34 are provided for each substrate S. In other words, the first candidate group, the second candidate group, one N ₂ gas inlet 33 and two NF ₃ gas inlets 34 are associated with each substrate S. In the etching of one substrate S, an NH ₃ gas inlet selected from a plurality of first candidates 31 associated with the substrate S, an HF gas inlet selected from a plurality of second candidates 32, and an N ₂ gas The gas introduced from the inlet 33 and the NF ₃ gas inlet 34 mainly contributes.

The first candidate group, the second candidate group, the N ₂ gas inlet 33 and the NF ₃ gas inlet 34 associated with one substrate S are, for example, on a plane on which the substrate S is expanded. is located Alternatively, in the direction in which the plurality of substrates S overlap, the first candidate group, the second candidate group, the N ₂ gas inlet 33 and the NF ₃ gas inlet 34 associated with one substrate S are It is located above (S) and is located below the substrate (S) located directly above the substrate (S).

The etching apparatus 10 may further include a moving mechanism for moving the target sphere to change the distance between the target sphere selected from the first candidate group and the target sphere selected from the second candidate group. As a result, since it is possible to change the distance between the target sphere selected from the first candidate group and the target sphere selected from the second candidate group by the moving mechanism moving the target sphere, the etching amount in the surface of the substrate S It is possible to change the distribution of

In the example shown in FIG. 4 , the second first candidate 31 located in the center in FIG. 4 of the first candidate group, before the movement of the target ball, introduces the NH ₃ gas to one NH ₃ gas inlet of the target ball. It is chosen as a district. The etching apparatus 10 is, for example, the one located at the far left of the first candidate group in FIG. 4 by switching the opening and closing of a valve located between the NH ₃ gas supply unit 23 and the NH ₃ gas inlet that is the supply source. The first first candidate 31 is selected as the NH ₃ gas inlet. As a result, the NH ₃ gas inlet moves from the position before the movement to the position after the movement.

In addition, the etching apparatus 10 switches the valve located between the NH ₃ gas supply unit 23 and the NH ₃ gas inlet, which is the supply source, to select the first candidate 31 on the leftmost side in FIG. 4 from among the first candidate group. In FIG. 4 , both sides of the first candidate 31 located in the center may be selected as the NH ₃ gas inlet. In this way, it is also possible to change the position of the NH ₃ gas inlets and to change the number of NH ₃ gas inlets.

The etching device 10 may include a plurality of NH ₃ gas supply units 23 . In this case, the number of NH ₃ gas supply units 23 may be equal to the number of first candidates 31 or may be less than the number of first candidates 31 .

When the etching apparatus 10 includes a plurality of NH ₃ gas supply units 23 , the etching apparatus 10 includes, for example, the NH ₃ gas supply units 23 for supplying the NH ₃ gas to the processing chamber 11 . You can switch. In this way, the etching device 10 can move the NH ₃ gas inlet from the position before the movement to the position after the movement. The etching apparatus 10 is applied from the NH ₃ gas supply unit 23 connected to the leftmost first candidate 31 in FIG. 4 from among the first candidate group to the rightmost first candidate 31 in FIG. 4 from the first candidate group. The position of the NH ₃ gas inlet may be switched by switching to the connected NH ₃ gas supply unit 23 .

Alternatively, the etching apparatus 10 is connected to the NH ₃ gas supply unit 23 connected to the leftmost first candidate 31 in FIG. 4 and the rightmost first candidate 31 in FIG. 4 among the first candidate groups. The NH ₃ gas may be supplied from both sides of the NH ₃ gas supply unit 23 . In this way, the two first candidates 31 are each selected as the NH ₃ gas inlet. Consequently, it is also possible to change the position of the NH ₃ gas inlets and to change the number of NH ₃ gas inlets.

In this case, in the case where only the NH ₃ gas inlet is set as the target zone, the etching device 10 includes the NH ₃ gas supply unit 23 for controlling the flow rate of the NH ₃ gas supplied from the corresponding target zone for each target zone. Each is provided. Since one NH ₃ gas supply unit 23 is provided for one NH ₃ gas inlet, it is possible to increase the degree of freedom of combination in the flow rate of gas supplied from each NH ₃ gas inlet.

The NH ₃ gas supply unit 23 may control the flow rate of the NH ₃ gas so as to change the flow rate ratio of the NH ₃ gas introduced from each target sphere. For example, before controlling the flow rate, the flow rate of the NH ₃ gas introduced from the leftmost NH ₃ gas inlet in FIG. 4 is set to the flow rate A, and also the rightmost NH ₃ gas inlet in FIG. 4 When the flow rate of the NH ₃ gas introduced in is set to the flow rate B, the total flow rate of the NH ₃ gas is the flow rate A+B. Next, the set value in the NH ₃ gas supply unit 23 connected to the leftmost NH ₃ gas inlet is changed to the flow rate (A-α), and further connected to the rightmost NH ₃ gas inlet. The set value in the NH ₃ gas supply unit 23 may be changed to the flow rate (B+α).

Further, for example, by setting predetermined conductances in the branched gas passages connected to each target sphere in advance, the flow rate ratio of the NH ₃ gas introduced from each target sphere can be set. In addition, this conductance can also be made variable.

In this case, it is possible to change the gas distribution within the plane of the substrate S. Thereby, it is possible to change the distribution of etching amount in the surface inside of the board|substrate S.

In addition, in the etching apparatus 10, the NH ₃ gas is supplied from the two NH ₃ gas supply units 23, and one of the NH ₃ gas supply units 23 is directed toward the two first candidates 31 with the NH ₃ gas. may supply Accordingly, the etching _apparatus 10 can introduce the NH 3 gas into the processing chamber 11 through the three NH ₃ gas introduction ports using the two NH ₃ gas supply units 23 .

On the other hand, in the example shown in FIG. 4 , the central second candidate 32 in FIG. 4 is selected as the HF gas inlet from the second candidate group before the target ball is moved for one of the target HF gas inlets. The etching device 10 is configured to, for example, switch the opening and closing of a valve located between the HF gas supply unit 24 and the HF gas inlet to be supplied, so that the second candidate group is the second one located at the far left in FIG. 4 among the second candidates. Candidate 32 is selected as the HF gas inlet. As a result, the HF gas inlet moves from the position before the movement to the position after the movement.

In addition, the etching apparatus 10 introduces HF gas to both of any two second candidates 32 from the second candidate group by switching the valve located between the HF gas supply unit 24 and the HF gas inlet that is the supply source. You can also choose by sphere. In this way, it is also possible to change the position of the HF gas inlets and change the number of HF gas inlets.

In addition, the etching device 10 may include a plurality of HF gas supply units 24 similarly to the NH ₃ gas supply unit 23 . In this case, the same number of HF gas supply units 24 as the second candidates 32 may be provided, or fewer HF gas supply units 24 may be provided than the second candidates 32 .

etching method

Referring to Figs. 5 to 8, the etching method will be described.

FIG. 5 is a timing diagram showing the timing at which gas is supplied from each of the supply units 21, 22, 23, 24, and 25 and the timing at which microwaves are oscillated from the microwave source 28 toward the discharge tube 26.

As shown in FIG. 5 , when the substrate S is etched, first, the control unit 10C drives the NH ₃ gas supply unit 23, the N ₂ gas supply unit 21, and the HF gas supply unit 24. Control (timing t1). In this way, since the NH ₃ gas supply unit 23 starts supplying the NH ₃ gas, the NH ₃ gas is introduced from the first candidate 31 selected to the NH ₃ gas inlet. Further, the HF gas supply unit 24 starts supplying the HF gas, whereby the HF gas is introduced from the second candidate 32 selected as the HF gas inlet. In addition, the N ₂ gas supply unit 21 starts supplying the N ₂ gas, whereby the N ₂ gas is introduced from the N ₂ gas inlet 33 .

After the supply of each gas continues from timing t1 until a predetermined period has elapsed, the control unit 10C controls the driving of the NH ₃ gas supply unit 23, the driving of the N ₂ gas supply unit 21, and the HF gas supply unit 24 ) is controlled (timing t2). In this way, since the NH ₃ gas supply unit 23 stops supplying the NH ₃ gas, introduction of the NH ₃ gas is stopped. Also, the HF gas supply section 24 stops the supply of the HF gas, thereby stopping the introduction of the HF gas. Also, the N ₂ gas supply unit 21 stops supplying the N ₂ gas, thereby stopping the introduction of the N ₂ gas.

After a predetermined period has elapsed from timing t2, the controller 10C controls the driving of the NH ₃ gas supply unit 22, the driving of the N ₂ gas supply unit 21, and the driving of the NF ₃ gas supply unit 25 (timing t3). The NH ₃ gas excited together with the N ₂ gas in the discharge tube 26 is introduced into the processing chamber 11 through the N ₂ gas inlet 33 .

Further, the NF ₃ gas supply unit 25 is connected to the gas distribution pipe 11C, whereby the NF ₃ gas is introduced into the processing chamber 11 through the NF ₃ gas inlet 34 . Alternatively, the NF ₃ gas supply unit 25 is connected to the shower head 11D, whereby NF ₃ gas from at least one of the first candidate 31 and the second candidate 32 is introduced into the processing chamber 11. good night.

Accordingly, since the NH ₃ gas supply unit 22 starts supplying the NH ₃ gas and the N ₂ gas supply unit 21 supplies the N ₂ gas, the mixed gas of the NH 3 gas and _{the N 2 gas} is supplied to the discharge tube ( 26) is supplied. Further, since the NF ₃ gas supply unit 25 starts supplying the NF ₃ gas, the NF ₃ gas is introduced through the gas inlet 34 of the gas dispersion pipe 11C.

After a predetermined period has elapsed from timing t3, the controller 10C controls driving of the microwave source 28 (timing t4). As a result, since the microwave source 28 oscillates microwaves, the microwaves are irradiated to the discharge tube 26 through the waveguide 27, and plasma is generated from the above-described mixed gas. Plasma generated from the mixed gas includes hydrogen radicals (H ^* ), which are an example of excited species. For this reason, after timing t4, H ^* is introduced from the N ₂ gas inlet 33.

After a predetermined period of time has elapsed from timing t4, the controller 10C controls driving of the NH ₃ gas supply unit 22, driving of the N ₂ gas supply unit 21, and operation of the NF ₃ gas supply unit 25 and the microwave source 28. Driving is controlled (timing t5). In this way, since the NH ₃ gas supply unit 22 stops supplying the NH ₃ gas, introduction of the NH ₃ gas is stopped. In addition, the NF ₃ gas supply unit 25 stops supplying the NF ₃ gas, thereby stopping the introduction of the NF ₃ gas. Also, the N ₂ gas supply unit 21 stops supplying the N ₂ gas, thereby stopping the introduction of the N ₂ gas. Also, the microwave source 28 stops oscillation of microwaves.

6 to 8 show states of a first processing target and a second processing target included in the substrate S for each step included in the etching method. 6 shows the state of the substrate S at timing t1, FIG. 7 shows the state of the substrate S at timing t4, and FIG. 8 shows the state of the substrate S at timing t5. indicates

As shown in FIG. 6 , one example of the substrate S includes a silicon nitride layer 51 , a silicon layer 52 and a silicon oxide layer 53 . The silicon layer 52 is an example of a first processing target, and the silicon oxide layer 53 is an example of a second processing target. The silicon nitride layer 51 has a concave portion, and a silicon layer 52 is positioned in the concave portion. A silicon oxide layer 53 is located on the silicon layer 52 . The silicon oxide layer 53 is, for example, a natural oxide film formed by exposing the silicon layer 52 to the atmosphere. The silicon layer 52 is formed of polysilicon. A modified silicon layer 52A is positioned on a surface of the silicon layer 52 in contact with the silicon oxide layer 53 . While the denatured silicon layer 52A is not a layer formed of silicon oxide, it is a portion modified by oxygen in the atmosphere as a result of the silicon layer 52 being exposed to the atmosphere.

At timing t1, NH ₃ gas and HF gas are introduced into the processing chamber 11 . Accordingly, the first etchant E1 is generated from the NH ₃ gas and the HF gas in the processing chamber 11 . The silicon oxide layer 53 is etched by supplying the first etchant E1 to the substrate S from timing t1 to timing t2. In this way, the period from timing t1 to timing t2 described above is the first step in which the silicon oxide layer 53 is etched.

The etching method may include a changing step of changing the distance between the target sphere and the center SC of the substrate S by changing the position of the target sphere prior to the first step. Thereby, it is possible to change the distribution of etching amount in the surface inside of the board|substrate S.

Further, the etching method may include a setting step of independently setting the flow rate of gas supplied from each of the target spheres in the plurality of target spheres prior to the first step. In this way, it is possible to set the flow rate of gas supplied from each target sphere. Accordingly, by changing the flow rate of the gas introduced from one target sphere or by changing the ratio between the flow rate of the gas supplied from the first target sphere and the flow rate of the gas supplied from the second target sphere, the substrate S It is possible to change the distribution of etching within the plane of .

Further, in the setting step, the flow rate of the gas introduced from each target sphere may be changed. In this way, the flow rate of the gas introduced from the target sphere is changed without changing the total flow rate of the gas introduced into the processing chamber 11 . For this reason, it is possible to change the distribution of the gas within the plane of the substrate S while suppressing the fluctuation of the pressure within the processing chamber 11 . Thereby, it is possible to change the distribution of etching amount in the surface inside of the board|substrate S.

As shown in FIG. 7 , at timing t4, excited species and NF ₃ gas are introduced into the processing chamber 11 from among the plasma generated from the mixed gas of NH ₃ gas and N ₂ gas, thereby discharging from the excited species and NF ₃ gas. A second etchant E2 is created. The modified silicon layer 52A is etched by supplying the second etchant E2 to the substrate S from timing t4 to timing t5.

As shown in Fig. 8, the modified silicon layer 52A is etched by supplying the second etchant E2 to the substrate S until timing t5. In this way, the period from timing t4 to timing t5 described above is a second step in which the modified silicon layer 52A, which is a part of the silicon layer 52, is etched.

Further, after timing t5, at least a reaction product containing silicon generated by reacting the second etchant E2 with the modified silicon layer 52A is located on the silicon layer 52. For this reason, when the board|substrate S on which the process by the 1st process and the process by the 2nd process were performed are heated by the 1st heating part 11A, the reaction product on the silicon layer 52 volatilizes.

Action

Referring to Figs. 9 to 12, the etching method and the operation of the etching apparatus will be described. 9 shows the selectivity of the silicon oxide layer 53 with respect to the silicon layer 52. The selectivity is the ratio of the etching amount of the silicon oxide layer 53 to the etching amount of the silicon layer 52 . 10 shows the selectivity of the silicon oxide layer 53 with respect to the silicon nitride layer 51 . The selectivity is the ratio of the etching amount of the silicon oxide layer 53 to the etching amount of the silicon nitride layer 51 .

In the case of using an excited species that is difficult to maintain an activated state, variation occurs in the supply amount of the activated excited species among the plurality of substrates S, and as a result, variation occurs in the etching amount among the substrates S. From this point of view, according to the first step of the present embodiment, since the NH ₃ gas and the HF gas are used to generate the first etchant E1, compared to the case where an excited species is used to generate the etchant, the substrate (S ), variation in the amount of the first etchant E1 is unlikely to occur. Thereby, it is suppressed that a variation arises in etching amount between the board|substrates S.

In addition, as shown in FIG. 9 , when the first process is performed according to an example of etching conditions, it can be seen that the selectivity ratio of the silicon oxide layer 53 to the silicon layer 52 is 107.1 in the first process. In contrast, when the second process is performed according to an example of etching conditions, it can be seen that the selectivity of the silicon oxide layer 53 to the silicon layer 52 is 5.0 in the second process.

On the other hand, as shown in FIG. 10, when the first step is performed according to an example of etching conditions, it can be seen that the selectivity ratio of the silicon oxide layer 53 to the silicon nitride layer 51 is 52.5 in the first step. . In contrast, when the second process is performed according to an example of etching conditions, it can be seen that the selectivity of the silicon oxide layer 53 to the silicon nitride layer 51 is 3.9 in the second process.

In this way, even if the second etching target is either the silicon layer 52 or the silicon nitride layer 51, according to the first process, the selectivity of the silicon oxide layer 53, the first target, is higher than that of the second process. it is possible to get Further, according to the second step, it is also possible to etch both the first processing target and the second processing target.

11 shows distribution of the etching amount (E/A) within the plane of the substrate S in the first step. In FIG. 11, a substrate having a radius of 150 mm and having a silicon oxide layer having a uniform thickness over the entire surface is used as an etching target. 11 shows the etching amount from the center of the substrate to a position separated by 147 mm in the radial direction of the substrate.

In addition, in FIG. 11, the introduction section distance, which is the distance between the NH ₃ gas inlet and the HF gas inlet when viewed from the viewpoint facing the plane on which the substrate is enlarged, is divided into three types: a first distance, a second distance, and a third distance are changing At a third distance from the first distance, the first distance is the shortest and the third distance is the longest. In FIG. 11, the etching amount when the introduction section distance is set to the first distance is indicated by a broken line. Further, the etching amount when the introduction section distance is set to the second distance is indicated by a solid line. In addition, the etching amount in the case where the introduction section distance is set to the third distance is indicated by a dashed-dotted line. In the case of changing the introduction section distance, both the position of the NH ₃ gas inlet and the position of the HF gas inlet in the process chamber 11 are changed.

As shown in Fig. 11, when the introduction section distance was set to the first distance, the etching amount at the center of the substrate was the smallest, and it was seen that the etching amount increased as the distance from the center of the substrate increased. Moreover, when the absolute value in the distance from the center of the board|substrate was equal, it was seen that the etching amount was also equal. That is, when the introduction section distance was set to the first distance, it was seen that the graph showing the relationship between the etching amount and the position on the substrate had a downward convex shape.

When the introduction section distance was set to the second distance, it was seen that the etching amount was greatest at the center of the substrate, and the etching amount decreased as the distance from the center of the substrate increased. Moreover, when the absolute value in the distance from the center of the board|substrate was equal, it was seen that the etching amount was also equal. That is, when the introduction section distance was set to the second distance, it was seen that the graph showing the relationship between the etching amount and the position on the substrate had an upwardly convex shape.

In the case where the introduction section distance was set to the third distance, similarly to the case where the introduction section distance was set to the second distance, it was seen that the graph showing the relationship between the etching amount and the position on the substrate had an upwardly convex shape. However, it was seen that the maximum value of the etching amount when set to the third distance was greater than the maximum value of the etching amount when set to the second distance. In addition, it was seen that the minimum value of the etching amount when set to the third distance was smaller than the minimum value of the etching amount when set to the second distance.

In this way, it is possible to change the distribution of the etching amount within the plane of the substrate by changing the distance between at least one of the NH ₃ gas inlet and the HF gas inlet and the center of the substrate.

FIG. 12 is a graph showing the relationship between the ratio of the introduction section distance and the etching amount for six examples in which only the introduction section distance is changed in the same etching process as FIG. 11 . 12 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. Accordingly, when the ratio of the etching amount is less than 1, the graph showing the relationship between the etching amount and the position in the substrate shows a downward convex shape. A graph representing the positional relationship shows an upward convex shape.

As shown in FIG. 12, in one example of the etching conditions, it was seen that the ratio of the etching amount was smaller than 1 in the range of the introduction section distance of 25 mm or less. On the other hand, it was seen that the ratio of the etching amount was larger than 1 in the range of the introduction section distance of 30 mm or more. In this way, it is possible to adjust the etching amount in the surface of the substrate by changing the introduction section distance, that is, the distance between the introduction hole and the center of the substrate.

As described above, according to one embodiment of the etching method and etching apparatus, the effects described below can be obtained.

(1) Since etching of the first process object is performed using NH ₃ gas and HF gas in the first process, compared to the case where etching is performed using plasma in both the first process and the second process Between the board|substrates S, it is hard to produce distribution in etching amount.

(2) By changing the distance between the object sphere and the center SC of the substrate S, it is possible to change the distribution of etching amount within the plane of the substrate S.

(3) It is possible to set the flow rate of gas supplied from each target sphere. For this reason, the substrate S is formed by changing the flow rate of the gas introduced from one target sphere or by changing the ratio of the flow rate of the gas supplied from the first target sphere to the flow rate of the gas supplied from the second target sphere. It is possible to change the distribution of etching in the plane of

(4) Since the flow rate of the gas introduced into the process chamber 11 from the target sphere is changed, it is possible to change the distribution of the gas within the surface of the substrate S. Thereby, it is possible to change the distribution of etching amount in the surface inside of the board|substrate S. In particular, by setting a predetermined conductance in advance in the branched gas passages connected to each target sphere, it is possible to change the combination in the flow rate of gas supplied from each target sphere without providing a flow control unit for all target spheres. .

(5) When the moving mechanism moves the target sphere, it is possible to change the distance between the target sphere and the center SC of the substrate S, thereby changing the distribution of the etching amount within the plane of the substrate S. possible.

(6) Since one supply part 23, 24 is provided for one target sphere, it is possible to increase the degree of freedom of combination in the flow rate of gas supplied from each target sphere.

In addition, you may implement the above-mentioned embodiment with a change as follows.

target ball

• In the etching apparatus 10, only one of the NH ₃ gas inlet and the HF gas inlet may be the target port. For example, when the NH ₃ gas inlet is the target port, the position of the HF gas inlet in the processing chamber 11 is fixed. In contrast, when the HF gas inlet is the target port, the position of the NH ₃ inlet in the processing chamber 11 is fixed.

• The change operation of changing the target ball from the first candidate to the second candidate may be performed by the user of the etching apparatus 10 . The change operation may be, for example, an operation of switching the opening and closing of the valve described above, or an operation of switching the connection destination of the NH ₃ gas supply unit 23 or the HF gas supply unit 24 from the first candidate to the second candidate. good night.

flow control

・As described above, when one NH ₃ gas supply unit 23 is connected to a plurality of pipes, and each pipe is connected to one first candidate 31, the plurality of pipes have a first conductance. and a pipe having a second conductance may be included. The first conductance is different from the second conductance. In this case, even if the setting value in the NH ₃ gas supply unit 23 is the same, the NH ₃ gas supply unit 23 has the second conductance compared to the case where a pipe having a first conductance is selected as a pipe for supplying the NH ₃ gas. It is possible to change the flow rate of NH ₃ gas when a pipe having is selected.

When one HF gas supply unit 24 is connected to a plurality of pipes, and each pipe is connected to one second candidate 32, the plurality of pipes include a pipe having a first conductance and a pipe having a second conductance Plumbing may be included. The first conductance is different from the second conductance. In this case, even if the set value in the HF gas supply unit 24 is the same, the case where the pipe having the first conductance is selected as the pipe through which the HF gas supply unit 24 supplies the HF gas and the pipe having the second conductance is selected In some cases it is possible to change the flow rate of HF gas.

In FIG. 4 , branch flow passages each connected to a plurality of first candidates 31 (three branch flow passages in the example of FIG. 4 ) and branch flow passages respectively connected to a plurality of second candidates 32 (shown in FIG. 4 ) In the example, you may provide one mass flow controller (flow control part) to each branch flow path) respectively.

moving device

· As shown in FIG. 13 , the etching device 10 may include a first moving mechanism 41 and a second moving mechanism 42 . The 1st moving mechanism 41 and the 2nd moving mechanism 42 are arrange|positioned in the processing chamber 11 at the position facing the exhaust part 11B. The 1st moving mechanism 41 is equipped with the 1st rotating part 41A, the 1st nozzle 41B, and the NH ₃ gas inlet 41C. The rotating part 41A, the first nozzle 41B, and the NH ₃ gas inlet 41C are installed in the processing chamber 11 . The first rotation unit 41A is configured to be capable of rotation, ie rotational movement, about a rotation axis extending in a direction parallel to the direction in which the processing chamber 11 extends. The 1st nozzle 41B is connected to the 1st rotating part 41A. The NH ₃ gas inlet 41C is located at the tip of the first nozzle 41B. An NH ₃ gas supply unit 23 is connected to the first rotation unit 41A. NH ₃ gas is supplied to the NH ₃ gas inlet 41C through the first rotating part 41A and the first nozzle 41B.

The 2nd moving mechanism 42 is equipped with the 2nd rotation part 42A, the 2nd nozzle 42B, and the HF gas inlet 42C. The 2nd rotation part 42A, the 2nd nozzle 42B, and the HF gas The inlet 42C is installed in the processing chamber 11 . The second rotation unit 42A is configured to rotate around a rotational axis extending in a direction parallel to the direction in which the processing chamber 11 extends, that is, rotationally move. The 2nd nozzle 42B is connected to the 2nd rotating part 42A. The NHF gas inlet 42C is located at the front end of the second nozzle 42B. The HF gas supply part 24 is connected to the 2nd rotation part 42A. HF gas is supplied to the HF gas inlet 42C through the second rotating part 42A and the second nozzle 42B.

The NH ₃ gas inlet 41C is an example of a first gas inlet, and the HF gas inlet 42C is an example of a second gas inlet. The NH ₃ gas inlet 41C and the HF gas inlet 42C are each positioned on a plane orthogonal to the normal line of the substrate S. The NH ₃ gas inlet 41C is configured so that the flowing direction of the NH ₃ gas introduced into the NH ₃ gas inlet 41C is parallel to the plane on which the substrate S extends. The HF gas inlet 42C is configured such that the flow direction of the HF gas introduced from the HF gas inlet 42C is parallel to the plane on which the substrate S is expanded, and is parallel to the flow direction of the NH ₃ gas.

The NH 3 gas inlet 41C is opened by at least one of the rotation of the first rotation unit 41A by the first movement mechanism 41 and the rotation of the second rotation unit 42A by _{the second} movement mechanism 42. It is possible to change the distance between the HF gas inlet 42C. Moreover, it is possible to change the angle at which the NH ₃ gas is introduced with respect to the substrate S by the first moving mechanism 41 rotating the first rotating portion 41A. Moreover, it is possible to change the angle at which the HF gas is introduced with respect to the substrate S by the second moving mechanism 42 rotating the second rotating portion 42A.

Moreover, according to the 1st moving mechanism 41, it is possible to change the distance between _NH3 gas inlet 41C and the center SC of the board|substrate S by rotating the 1st rotating part 41A. According to the 2nd moving mechanism 42, it is possible to change the distance between 42 C of HF gas introduction ports and the center SC of the board|substrate S by rotating 42 A of 2nd rotating parts. According to the etching apparatus 10, by using at least one of the 1st moving mechanism 41 and the 2nd moving mechanism 42, it is possible to change distribution of the etching amount in surface inside of the board|substrate S.

In addition, the amount of rotation of each of the rotating parts 41A and 42A, that is, the position of the inlets 41C and 42C in the processing chamber 11 may be changed by the control unit 10C or by the user of the etching apparatus 10. may be changed

1st process

• In the first step, all of the silicon oxide layer 53 may be removed, or a part of the silicon oxide layer 53 may remain on the substrate S. In addition, when a part of the silicon oxide layer 53 is left on the substrate S in the first process, a part of the silicon oxide layer 53 together with the silicon layer 52 or the silicon nitride layer 51 is formed in the second process. may be removed.

- The 1st process may be performed after the 2nd process.

10: etching device 11: processing chamber
21: N ₂ gas supply unit 22, 23: NH ₃ gas supply unit
24: HF gas supply unit 25: NF ₃ gas supply unit
26: discharge tube 27: waveguide
28: microwave source

Claims (22)

The plurality of substrates accommodated in the vacuum chamber each have 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 layer covered with a silicon nitride layer or the silicon oxide layer,
a first step of etching the first processing target by introducing NH ₃ gas and HF gas into the vacuum chamber;
and a second process of etching the second processing object by supplying plasma generated from a gas containing NH ₃ gas and NF ₃ gas to the vacuum chamber after the first process. . According to claim 1,
At least one of the NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber and the HF gas inlet for introducing HF gas into the vacuum chamber is an object hole;
and a changing step of changing a distance between the center of the substrate and the target sphere by changing the position of the target sphere before the first step. According to claim 1,
Either one of the NH ₃ gas inlet for introducing NH ₃ gas into the substrate and the HF gas inlet for introducing HF gas into the substrate is a target hole;
The etching method characterized in that it includes a setting step of independently setting a flow rate of gas supplied from each of the target spheres in the plurality of target spheres before the first step. According to claim 3,
The etching method according to claim 1 , wherein the setting step changes the flow rate of the gas introduced from each of the target spheres by presetting a conductance of a gas flow path of the gas introduced from the target sphere. The substrate has 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 layer covered with a silicon nitride layer or the silicon oxide layer,
a vacuum chamber accommodating a plurality of the substrates;
a first processing unit which etches the first processing object by introducing NH ₃ gas and HF gas into the vacuum chamber;
And a second processing unit for etching the second processing target by introducing plasma generated from a gas containing NH ₃ gas and NF ₃ gas into the vacuum chamber after etching the first processing target. etching device. According to claim 5,
An NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber;
Equipped with an HF gas inlet for introducing HF gas into the vacuum chamber;
At least one of the NH ₃ gas inlet and the HF gas inlet is a target port,
The etching device has a plurality of candidates for the target sphere,
The etching apparatus characterized in that the distance between the center of the substrate and one said candidate is different from the distance between said center and the other said candidate. According to claim 5,
An NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber;
Equipped with an HF gas inlet for introducing HF gas into the vacuum chamber;
At least one of the NH ₃ gas inlet and the HF gas inlet is a target port,
The etching apparatus further comprises a moving mechanism for moving the target sphere to change a distance between the center of the substrate and the target sphere. According to claim 5,
An NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber;
Equipped with an HF gas inlet for introducing HF gas into the vacuum chamber;
One of the NH ₃ gas inlet and the HF gas inlet is a target port,
The etching device includes a plurality of target spheres,
The etching device is characterized in that the etching device is provided with one flow rate controller for controlling the flow rate of the gas supplied from the target sphere for each target sphere. According to claim 8,
The etching apparatus according to claim 1 , wherein the flow control unit controls the flow rate of the gas so as to maintain a total flow rate of the gas introduced from all of the target spheres and change the flow rate of the gas introduced from each of the target spheres. A vacuum chamber accommodating a plurality of substrates;
a first gas inlet for introducing NH ₃ gas into the vacuum chamber;
a second gas inlet for introducing HF gas into the vacuum chamber;
and a mechanism for changing a distance between the first gas inlet and the second gas inlet. According to claim 10,
A third gas inlet for introducing NF ₃ gas;
An etching apparatus further comprising a fourth gas inlet for introducing discharged NH ₃ gas through the discharge tube. According to claim 10,
The NH ₃ gas introduced from one passage is branched into two or more first gas inlets,
HF gas introduced from one flow path is branched into two or more second gas inlets,
Between the target port of the NH ₃ 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 by selecting the branches of the NH ₃ gas and the HF gas Etching apparatus characterized in that it is provided with a mechanism for changing the distance of. According to claim 12,
The NH ₃ gas introduced from one passage is branched to a passage having a different conductance,
An etching apparatus characterized in that the HF gas introduced in one flow path is branched into a flow path having a different conductance. According to claim 10,
The NH ₃ gas introduced from one passage is branched into two or more of the first gas inlets,
HF gas introduced from one flow path is branched into two or more second gas inlets,
Etching apparatus, characterized in that each of the branched flow passages has one flow rate controller. According to claim 10,
Since the first gas inlet and the second gas inlet are disposed on a plane orthogonal to the normal line of the substrate, the gases introduced from the first gas inlet and the second gas inlet are parallel to the substrate. and are provided so as to flow in parallel with each other,
and a mechanism for rotationally moving the first gas inlet and the second gas inlet around an axis parallel to a normal line of the substrate installed in the vacuum chamber. For a plurality of substrates accommodated in a vacuum chamber,
a first process performed by introducing NH ₃ gas and HF gas into the vacuum chamber;
and a second process performed by supplying NF ₃ gas and plasma generated from a gas containing NH ₃ gas to the vacuum chamber. According to claim 16,
The object of the first treatment is a silicon oxide layer,
The etching method according to claim 1, wherein the object of the second processing is a silicon layer covered with a silicon nitride layer or the silicon oxide layer. According to claim 17,
The etching method characterized in that, after the first treatment, the second treatment is performed. According to claim 16,
In the first process,
The NH ₃ gas introduced from one passage is branched into two or more first gas inlets,
The HF gas introduced from one flow path is branched into two or more second gas inlets,
The distance between the target port of the NH ₃ 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 by selecting branches of the NH ₃ gas and the HF gas Etching method characterized in that for changing. According to claim 19,
The NH ₃ gas introduced from one passage is branched into passages having different conductances,
The HF gas introduced in the one passage is branched into passages having different conductances,
The etching method characterized in that the NH ₃ gas and the HF gas are introduced from a target hole of the NH ₃ gas inlet and a target hole of the HF gas inlet at different flow rates, respectively. According to claim 16,
In the first process,
The NH ₃ gas introduced from one passage is branched into two or more first gas inlets,
The HF gas introduced from one flow path is branched into two or more second gas inlets,
The distance between the target port of the NH ₃ 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 by selecting branches of the NH ₃ gas and the HF gas change,
An etching method characterized in that the NH ₃ gas and the HF gas are introduced from a target hole of the NH ₃ gas inlet and a target hole of the HF gas inlet at different flow rates by flow control units provided in each of the branched passages. According to claim 16,
In the first process, NH ₃ gas is introduced from the first gas inlet and HF gas is introduced from the second gas inlet;
The first gas inlet and the second gas inlet are disposed on a plane orthogonal to the normal line of the substrate, so that the gases introduced from the first gas inlet and the second gas inlet are parallel to the substrate and , are provided to flow parallel to each other,
The distance between the first gas inlet and the second gas inlet is determined by rotationally moving the first gas inlet and the second gas inlet around an axis parallel to the normal line of the substrate installed in the vacuum chamber. An etching method characterized by changing the introduction angle of the NH ₃ gas and the introduction angle of the HF gas at the same time.

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