JP7407162B2 - Etching method and etching device - Google Patents

Description

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

2. Description of the Related Art An oxide film removal apparatus is known that removes a natural oxide film formed on the surface of a silicon substrate by etching. The oxide film removal device uses radicals contained in plasma generated using microwaves to generate an etchant for the natural oxide film, and the generated etchant converts the natural oxide film into a complex containing silicon. The thermal decomposition temperature of the complex is lower than that of the native oxide film. Then, the oxide film removal device vaporizes the complex from above the silicon substrate by heating the silicon substrate together with the complex. Thereby, the oxide film removal device removes the natural oxide film from the silicon substrate. The oxide film removal apparatus is capable of processing multiple silicon substrates at once (see, for example, Patent Document 1).

Furthermore, it is known that etching can be performed in the same manner as the oxide film removal apparatus described above without using plasma generated using microwaves. By changing the type of gas used for etching, the oxide film can be removed without using plasma.

International Publication No. 2012/002393

Incidentally, in the case of a batch-type apparatus that processes a plurality of substrates at the same time, a plurality of gases for generating etchants are blown from the outer periphery of the substrate in the processing tank of the apparatus. The etchant sprayed from the outer periphery undergoes an etching reaction and is consumed on the substrate surface before proceeding to the exhaust section provided in the processing tank, so the etchant concentration during processing in the processing tank changes depending on the amount consumed. A distribution occurs. This causes a distribution in the etching rate of the substrate surface, resulting in a distribution in the target etching amount.

Note that such a problem also occurs when the substrate to be etched includes not only a silicon oxide layer but also a silicon nitride layer. It is also known that the larger the surface area of the object to be treated, the greater the effect.

Furthermore, in etching using plasma, radicals used to generate an etchant lose their excited state due to collisions with other gases, the inside of the induced radical guide tube, and the walls of the dispersion mechanism. Therefore, among the plurality of silicon substrates, the amount of excited radicals reaching the silicon substrates varies depending on the shape of the radical guide tube and the dispersion mechanism in the oxide film removal apparatus. 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, each of a plurality of substrates housed in a vacuum chamber 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 layer covered with a silicon nitride layer or the silicon oxide layer, and the first processing target is etched by introducing NH ₃ gas and HF gas into the vacuum chamber. a first step, and a second step of etching the second target by supplying plasma generated from a gas containing _NH3 gas and _NF3 gas to the vacuum chamber after the first step; ,including.

According to the above etching method, in the first step, the first processing target is etched using NH ₃ gas and HF gas, so when etching is performed using plasma in both the first step and the second step, Compared to the above, the etching amount is less likely to be distributed among the substrates.

In the above etching method, at least one of an NH ₃ gas introduction port for introducing NH ₃ gas into the vacuum chamber and an HF gas introduction port for introducing HF gas into the vacuum chamber is the target port, and the first step The method may further include a changing step of changing the distance between the center of the substrate and the target aperture by changing the position of the target aperture. According to this etching method, by changing the distance between the target opening and the center of the substrate, it is possible to change the distribution of the amount of etching within the plane of the substrate.

In the above etching method, either the NH ₃ gas introduction port for introducing NH ₃ gas into the substrate or the HF gas introduction port for introducing HF gas into the substrate is the target port, and from the first step The method may also include a setting step of independently setting the flow rate of gas supplied from each target port in the plurality of target ports.

According to the above etching method, it is possible to set the flow rate of gas supplied from each target port, so it is possible to change the flow rate of gas introduced from one target port or from the first target port. It is possible to change the etching distribution within the plane of the substrate by, for example, changing the ratio of the flow rate of the supplied gas to the flow rate of the gas supplied from the second target port.

In the etching method described above, in the setting step, the total flow rate of the gas introduced from all the target ports may be maintained, and the flow rate of the gas introduced from each target port may be changed. According to this etching method, 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, so the gas flow within the plane of the substrate is suppressed while suppressing pressure fluctuations within the vacuum chamber. It is possible to change the distribution of This makes it possible to change the distribution of etching amount within the plane of the substrate.

In an etching apparatus for solving the above problems, the 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 a silicon layer covered with the silicon oxide layer, and the first processing target is etched by introducing a vacuum chamber containing a plurality of the substrates and NH ₃ gas and HF gas into the vacuum chamber. After the processing by the first processing section and the first processing object, plasma generated from a gas containing NH ₃ gas and NF ₃ gas are introduced into the vacuum chamber, thereby treating the second processing object. and a second processing section for etching.

According to the etching apparatus, the first processing section etches the first processing target using NH ₃ gas and HF gas, so both the first processing section and the second processing section perform etching using plasma. Compared to the case, the etching amount is less likely to be distributed among the substrates.

The etching apparatus described above includes an NH ₃ gas introduction port for introducing NH ₃ gas into the vacuum chamber, and an HF gas introduction port for introducing HF gas into the vacuum chamber, and the NH ₃ gas introduction port and the HF gas At least one of the introduction ports is a target opening, and the etching apparatus includes a plurality of candidates for the target opening, and the distance between the center of the substrate and one of the candidates is such that the distance between the center and the other It may be different from the distance between the candidate and the candidate.

According to the above-mentioned etching apparatus, since a plurality of candidates for the target opening are provided, the difference between the target opening and the substrate between the case where the first candidate is selected as the target opening and the case where the second candidate is selected as the target opening is determined. It is possible to change the distance from the center. Thereby, it is possible to change the distribution of the etching amount in the plane of the substrate between the case where the first candidate is selected as the target hole and the case where the second candidate is selected as the target hole.

The etching apparatus described above includes an NH ₃ gas introduction port for introducing NH ₃ gas into the vacuum chamber, and an HF gas introduction port for introducing HF gas into the vacuum chamber, and the NH ₃ gas introduction port and the HF gas At least one of the introduction port and the target port may be a target port, and the etching apparatus may further include a moving mechanism that moves the target port so as to change a distance between the center of the substrate and the target port. .

According to the etching apparatus described above, by moving the target opening by the moving mechanism, it is possible to change the distance between the target opening and the center of the substrate, thereby controlling the distribution of the etching amount within the plane of the substrate. It is possible to change.

The etching apparatus described above includes an NH ₃ gas introduction port for introducing NH ₃ gas into the vacuum chamber, and an HF gas introduction port for introducing HF gas into the vacuum chamber, and the NH ₃ gas introduction port and the HF gas Either one of the inlet port and the target port is a target port, the etching device includes a plurality of target ports, and the etching device controls the flow rate of gas supplied from the target port to each target port. One flow control section may be provided. According to this etching apparatus, since one flow rate control section is provided for one target port, it is possible to increase the degree of freedom in combining the flow rates of gases supplied from each target port.

In the etching apparatus, the flow rate control unit controls the flow rate of the gas so as to maintain the total flow rate of the gas introduced from all the target ports and to change the flow rate of the gas introduced from each target port. You can.

According to the above etching apparatus, the flow rate controller changes the flow rate of the gas introduced from the target port without changing the total gas flow rate, thereby suppressing pressure fluctuations in the vacuum chamber and distributing the gas within the plane of the substrate. It is possible to change. This makes it possible to change the distribution of etching amount within the plane of the substrate.

An etching apparatus for solving the above problems includes a vacuum chamber that accommodates a plurality of substrates, a first gas inlet for introducing _NH3 gas into the vacuum chamber, and 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.

According to the above etching apparatus, the distance between the first gas introduction port for introducing _NH3 gas and the second gas introduction port for introducing HF can be changed, so that etching of the silicon oxide layer can be performed. Since the position where the etchant is synthesized within the vacuum chamber can be changed, the etching distribution within the substrate surface can be adjusted.

The etching apparatus may include a third gas introduction port for introducing NF ₃ gas and a fourth gas introduction port for introducing NH ₃ gas discharged through the discharge tube.
According to the above etching apparatus, it is possible to combine etching using plasma for silicon nitride layers and silicon layers that are not etched by etching that does not use plasma, and there is a high degree of freedom in etching selectivity of silicon nitride film layers and silicon layers. can be increased.

In the above etching apparatus, 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 first gas introduction ports. The second gas inlet is branched into two or more of the second gas inlets, and by selecting the branch for _NH3 gas and HF gas, the distance between the target port of the _NH3 gas inlet and the HF gas inlet changes. It may be provided with a mechanism to do so.

According to the above etching apparatus, the distance between the first gas introduction port for introducing _NH3 gas and the second gas introduction port for introducing HF can be changed, so that etching of the silicon oxide layer can be performed. Since the position where the etchant is synthesized within the vacuum chamber can be changed, the etching distribution within the substrate surface can be adjusted.

In the above etching apparatus, _NH3 gas introduced from one channel is branched into channels having different conductances, and HF gas introduced from one channel is branched into channels having different conductances. may be done.

According to the above-mentioned etching apparatus, it is possible to adjust in advance 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 set.

In the above etching apparatus, 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 first gas introduction ports. The flow path may be branched into two or more second gas introduction ports, and each branched flow path may be provided with one flow rate control section.

According to the above etching apparatus, by having one flow rate control unit for each inlet, it is possible to adjust the gas distribution to generate finer etchant, and it has a degree of freedom in adjusting the distribution within the substrate surface. can be set.

In the above etching apparatus, the first gas inlet and the second gas inlet are arranged in parallel to the normal line of the substrate and on a straight line, and further, the introduced gas is parallel to the substrate and parallel to each other. The first gas inlet and the second gas inlet are attached to an axis parallel to the normal line of the substrate installed in the vacuum chamber, and the axis is A mechanism for rotationally moving the center may be provided.
According to the above etching apparatus, the positional relationship and angle of the introduction port can be set continuously, and the position where the etchant is synthesized in the vacuum chamber can be changed more precisely.

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

In the above etching method, the object of the first treatment may be a silicon oxide layer, and the object of the second treatment may be a silicon nitride layer or a silicon layer covered with the silicon oxide layer.

According to the above etching method, it is possible to combine etching using plasma for silicon nitride layers and silicon layers that are not etched by etching that does not use plasma, and there is a high degree of freedom in etching selectivity of silicon nitride film layers and silicon layers. can be increased.

In the etching method described above, the second treatment may be performed after the first treatment.
According to the above etching method, the first treatment is not affected by the etching distribution caused by the radicals received in the first treatment.

In the above etching method, in the first process, the NH ₃ gas introduced from one flow path is branched to two or more of the first gas introduction ports, and the NH 3 gas introduced from one flow path is The introduced HF gas is branched to two or more of the second gas introduction ports, and by selecting branches for NH ₃ gas and HF gas, the first introduction port and the second gas introduction port are selected. The distance between the mouths may be varied.

According to the above etching method, the distance between the first gas introduction port for introducing NH ₃ gas and the second gas introduction port for introducing HF can be changed, so that etching of the silicon oxide layer is performed. Since the position where the etchant is synthesized within the vacuum chamber can be changed, the etching distribution within the substrate surface can be adjusted.

In the above etching method, NH ₃ gas introduced from one channel is branched into channels with different conductances, and HF gas introduced from one channel is branched into channels with different conductances. The NH3 gas and the HF gas may be introduced from the first gas introduction port and the second gas introduction port at different flow rates.

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

In the above etching method, in the first process, the NH ₃ gas introduced from one flow path is branched to two or more of the first gas introduction ports, and the NH 3 gas introduced from one flow path is The HF gas is branched to two or more of the second gas introduction ports, and the _NH3 gas and the HF gas are controlled to be different from each other by a flow rate control unit provided in each of the branched channels. The gas may be introduced from the first gas introduction port and the second gas introduction port using a combination of flow rates and different distances.

According to the above-mentioned etching method, the distribution of the gas for generating the etchant can be adjusted in advance more finely, so that the etching distribution within the substrate surface can be adjusted with a greater degree of freedom.

In the etching method, in the first process, the gases are arranged parallel to the normal line of the substrate and on a straight line, and the gases to be introduced are arranged parallel to the substrate and parallel to each other, and Rotating each introduction port around the axis from the first gas introduction port and the second gas introduction port attached to an axis parallel to the normal line of the substrate installed in the vacuum chamber, The NH ₃ gas and the HF gas may be introduced after setting the distance of the first gas introduction port and the distance and introduction angle of the second gas introduction port.

According to the above etching method, the positional relationship and angle of the introduction port can be set continuously, and the position where the etchant is synthesized in the vacuum chamber can be changed more precisely.

FIG. 1 is an apparatus configuration diagram showing the configuration of an etching apparatus in one embodiment. 2 is an apparatus configuration diagram showing the configuration of a processing chamber included in the etching apparatus shown in FIG. 1. FIG. 3 is a schematic diagram showing candidates for an NH ₃ gas introduction port and a candidate for an HF gas introduction port included in the processing chamber shown in FIG. 2. FIG. FIG. 3 is a schematic diagram showing the relationship between NH ₃ gas introduction port candidates, HF gas introduction port candidates, and the substrate. 5 is a timing chart for explaining an etching method in one embodiment. FIG. 3 is a process diagram showing one step in an etching method. FIG. 3 is a process diagram showing one step in an etching method. FIG. 3 is a process diagram showing one step in an etching method. A graph showing the selectivity of a silicon oxide layer to a silicon layer. 3 is a graph showing the selectivity of a silicon nitride layer to a silicon layer. A graph showing the relationship between the position on the substrate and the amount of etching. A graph showing the relationship between the distance between the introduction ports and the etching amount ratio. FIG. 6 is a schematic diagram showing candidates for an NH ₃ gas introduction port and a candidate for an HF gas introduction port in a modified example of the etching apparatus.

An embodiment of an etching method and an etching apparatus will be described with reference to FIGS. 1 to 12.

[Etching equipment]
The etching apparatus will be described with reference to FIGS. 1 to 4.
The etching apparatus 10 shown in FIG. 1 is configured to be able to simultaneously etch a plurality of substrates. The substrate includes a first processing target and a second processing target. The first processing target is a silicon oxide layer. The second treatment target is a silicon nitride layer or a silicon layer covered with the first treatment target, a silicon oxide layer.

The etching apparatus 10 includes a processing chamber 11 and a loading/unloading chamber 12. The processing chamber 11 is an example of a vacuum tank that accommodates a substrate. In the processing chamber 11, etching of the substrate is performed. The carry-in/out chamber 12 carries in the substrate before the etching process in the processing chamber 11 from the outside of the carry-in/out chamber 12 , and carries out the substrate after the etching process to the outside of the carry-in/out chamber 12 .

A gate valve 13 is located between the processing chamber 11 and the loading/unloading chamber 12. The gate valve 13 has an open state and a closed state. By opening the gate valve 13, the space defined by the processing chamber 11 is connected to the space defined by the loading/unloading chamber 12. On the other hand, by closing the gate valve 13, the space defined by the processing chamber 11 is separated from the space defined by the loading/unloading chamber 12.

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

The etching apparatus 10 includes a nitrogen ( _N2 ) gas supply section 21, ammonia ( _NH3 ) gas supply sections 22 and 23, a hydrogen fluoride (HF) gas supply section 24, and a nitrogen trifluoride ( _NF3 ) gas supply section. 25. NH ₃ gas, HF gas, and NF ₃ gas are gases for generating an etchant that etches the substrate, and N ₂ gas is supplied to the destination together with NH ₃ gas, HF gas, and NF ₃ gas. It is a carrier gas.

Each supply section 21, 22, 23, 24, 25 is, for example, a mass flow controller, and is connected to a cylinder that stores the gas supplied by each supply section 21, 22, 23, 24, 25. A mass flow controller is an example of a flow rate control unit. A valve is located between each supply section 21, 22, 23, 24, 25 and the supply destination of the supply section 21, 22, 23, 24, 25. When the valves are opened, the gases supplied by the respective supply sections 21, 22, 23, 24, and 25 flow into the supply destination. On the other hand, since the valves are closed, the gases supplied by the respective supply sections 21, 22, 23, 24, and 25 do not flow into the supply destination.

The etching apparatus 10 includes a discharge tube 26, a waveguide 27, and a microwave source 28. The discharge tube 26 is irradiated with microwaves oscillated by a microwave source 28 via a 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. NH ₃ gas and N ₂ gas are excited by irradiating the discharge tube 26 with microwaves while the NH ₃ gas and N ₂ gas are supplied to the discharge tube 26 . That is, plasma is generated from a mixed gas of NH ₃ gas and N ₂ gas. Excitation of the gas mixture produces H ^* , NH ^* , _NH2 ^* , and _N2 ^* .

The N ₂ gas supply section 21 and the NH ₃ gas supply section 22 are connected to the discharge tube 26 through one pipe.
The NH ₃ gas supply section 23 , the HF gas supply section 24 , and the NF ₃ gas supply section 25 are connected to the processing chamber 11 . The NH ₃ gas supply section 23, the HF gas supply section 24, and the NF ₃ gas supply section 25 are connected to the processing chamber 11 through individual piping.

A vent gas supply section 12A is connected to the carry-in/out chamber 12. The venting gas supply section 12A supplies venting gas into the carry-in/out chamber 12 for cooling the substrate after etching processing. The venting gas may be, for example, _N2 gas. The venting gas supply unit 12A is, for example, a mass flow controller, and is connected to a cylinder that stores venting gas.

The etching apparatus 10 further includes a control section 10C. The control section 10C controls the driving of each section included in the etching apparatus 10. Thereby, the control unit 10C enables the etching apparatus 10 to etch the first processing target and the second processing target.

The control unit 10C includes a storage unit 10CM. A process recipe is stored in the storage unit 10CM. A process recipe includes multiple process steps that make up the process recipe. The process recipe includes setting values regarding the operation of the processing chamber 11, the loading/unloading chamber 12, and each part connected to the processing chamber 11 in each process step. After reading the process recipe, the control unit 10C reads out the setting values defined 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 22 and the HF gas supply unit 24, thereby introducing NH ₃ gas and 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, thereby causing the plasma generated from the gas containing NH ₃ gas and the NF ₃ gas is supplied to the processing chamber 11. Thereby, the control unit 10C executes the first step, ie, the first process, and the second step, ie, the second process, included in the etching method performed in the etching apparatus 10.

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

FIG. 2 shows the structure of the processing chamber 11. Note that in FIG. 2, illustration of the first heating section 11A is omitted for convenience of explaining functional sections other than the first heating section 11A included in the processing chamber 11.

As shown in FIG. 2, the etching apparatus 10 includes a support section 10A that supports the substrate S. As shown in FIG. The support section 10A supports a plurality of substrates S in a stacked state with a gap G between the substrates S. In FIG. 2, the support part 10A is located in the processing chamber 11, but the etching apparatus 10 has a mechanism that can move the support part 10A between the loading/unloading chamber 12 and the processing chamber 11. We are prepared. Thereby, the etching apparatus 10 moves the support portion 10A from the loading/unloading chamber 12 to the processing chamber 11 or from the processing chamber 11 to the loading/unloading chamber 12 while the gate valve 13 is open.

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

Inside the processing chamber 11, a gas dispersion tube 11C is located. The gas distribution tube 11C has a plurality of holes for dispersing the gas supplied to the gas distribution tube 11C within the processing chamber 11.

A shower head 11D separate from the gas dispersion pipe 11C is attached to the processing chamber 11. The shower head 11D has an inlet. Since the introduction port of the shower head 11D is exposed in the space defined by the processing chamber 11, various gases are introduced into the processing chamber 11 from the introduction port of the shower head 11D.

An NH ₃ gas supply unit 22 is connected to the shower head 11D via a discharge tube 26. Furthermore, the NF ₃ gas supply section 25 is connected to the gas dispersion tube 11C without the discharge tube 26 interposed therebetween.

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 shower head 11D through individual piping without using the discharge tube 26.

The processing chamber 11 includes a rotating section 11E. The rotating part 11E is configured to be connectable to the supporting part 10A when the supporting part 10A is located in the processing chamber 11. The rotating part 11E rotates the supporting part 10A with the central axis of the supporting part 10A as a rotation axis when connected to the supporting part 10A. The rotating section 11E rotates the support section 10A from the start to the end of etching for the first processing object and the second processing object. Therefore, in the substrate S, the amount of etching at a predetermined position in the radial direction of the substrate S is approximately constant in the circumferential direction of the substrate S.

FIG. 3 schematically shows inlets for introducing various gases into the processing chamber 11. Note that FIG. 3 schematically shows a plurality of gas inlets corresponding to one substrate S.
The etching apparatus 10 includes an NH ₃ gas introduction port for introducing NH ₃ gas into the processing chamber 11 and an HF gas introduction port for introducing HF gas into the processing chamber 11 . At least one of the NH ₃ gas inlet and the HF gas inlet is the target port. The NH ₃ gas introduction port is an example of the first gas introduction port, and the HF gas introduction port is an example of the second gas introduction port. The etching apparatus 10 includes a plurality of target opening candidates. 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 the other candidates.

Since the etching apparatus 10 of the present disclosure includes a plurality of candidates for the target hole, between the case where the first candidate is selected as the target hole and the case where the second candidate is selected as the target hole, the target hole and the substrate It is possible to change the distance between the center of Thereby, it is possible to change the distribution of the etching amount in the plane of the substrate between the case where the first candidate is selected as the target hole and the case where the second candidate is selected as the target hole.

For example, 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 that are candidates for NH ₃ gas introduction ports, and a plurality of second candidates 32 that are candidates for HF gas introduction ports. 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. Note that in FIG. 3, for convenience of illustration, the shower head 11D is not shown, and each of the candidates 31 and 32 is schematically shown.

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 consecutively arranged along one direction. In the second candidate group, the first second candidate 32, the second second candidate 32, and the third second candidate 32 are arranged consecutively. An NH ₃ gas supply unit 23 is connected to the first candidate group. The flow path for supplying _NH3 gas to the first candidate 31 is branched into three flow paths from one flow path to which the _NH3 gas supply unit 23 is connected, and each flow path after branching is It is connected to one first candidate 31. The HF gas supply section 24 is connected to the second candidate group. The flow path for supplying HF gas to the second candidate 32 is branched into three flow paths from one flow path to which the HF gas supply unit 24 is connected, and each flow path after branching is one flow path. It is connected to the second candidate 32.

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

In this example, for example, the first candidate 31 located on the leftmost side of the first candidate group is selected as the NH ₃ gas inlet, and the second candidate 32 located on the leftmost side of the second candidate group is selected as the HF gas inlet. NH ₃ gas is supplied into the processing chamber 11 from the NH ₃ gas introduction port, and HF gas is supplied into the processing chamber 11 from the HF gas introduction port.

The exhaust section 11B faces the first candidate 31 and the second candidate 32 when viewed from a viewpoint facing the surface on which the substrate S spreads. Thereby, the substrate S is sandwiched between the first candidate 31, the second candidate 32, and the exhaust section 11B. Therefore, the _NH3 gas introduced into the processing chamber 11 from the _NH3 gas inlet flows toward the exhaust part 11B via the substrate S, and the NH3 gas introduced into the processing chamber 11 from the HF gas inlet The gas flows through the substrate S toward the exhaust section 11B.

The etching apparatus 10 also includes an N ₂ gas introduction port 33 and an NF ₃ gas introduction port 34 . The N ₂ gas supply section 21 is connected to the N ₂ gas inlet 33 . The N ₂ gas supply section 21 and the NH ₃ gas supply section 22 are connected to the N ₂ gas introduction port 33 . In this example, the N ₂ gas inlet 33 is located between the first candidate group and the second candidate group. The NF ₃ gas supply section 25 is connected to the NF ₃ gas inlet 34 . In this example, the NF ₃ gas introduction port 34 is arranged at a position away from the first candidate group, the second candidate group, and the N ₂ gas introduction port 33 . The NF ₃ gas introduction port 34 is an example of a third gas introduction port, and the N ₂ gas introduction port 33 is an example of a fourth gas introduction port.

FIG. 4 shows a plurality of substrates S supported by the support section 10A and the relationship between each substrate S and the gas introduction port. Furthermore, a method for setting the distance between the target port for NH ₃ gas selected from the first candidate group and the target port for HF gas selected from the second candidate group will be described below.

As shown in FIG. 4, the etching apparatus 10 includes the above-described first candidate group, second candidate group, _N2 gas inlet 33, and _NF3 gas inlet 34 for each substrate S. In other words, each substrate S is associated with one first candidate group, one second candidate group, one N ₂ gas introduction port 33, and two NF ₃ gas introduction ports 34. For etching one substrate S, an NH ₃ gas introduction port selected from the first candidate 31 linked to the substrate S, an HF gas introduction port selected from the second candidate 32, and an N ₂ gas introduction port 33 are used. , and the gas introduced from the NF ₃ gas inlet 34 mainly contribute.

The first candidate group, the second candidate group, the _N2 gas inlet 33, and the _NF3 gas inlet 34 linked to one substrate S are located, for example, on a plane on which the substrate S spreads. . Alternatively, in the direction in which a plurality of substrates S are stacked, the first candidate group, the second candidate group, the _N2 gas inlet 33, and the _NF3 gas inlet 34 linked to one substrate S are connected to the substrate S. The substrate S is located above the substrate S and is located below the substrate S that is directly above the substrate S.

The etching apparatus 10 may further include a moving mechanism that moves the target opening so as to change the distance between the target opening selected from the first candidate group and the target opening selected from the second candidate group. good. Thereby, by moving the target mouth by the moving mechanism, it is possible to change the distance between the target mouth selected from the first candidate group and the target mouth selected from the second candidate group. It is possible to change the distribution of the etching amount within the plane of the substrate S.

For example, in the example shown in FIG. 4, for the NH ₃ gas inlet, which is one of the target ports, before the target port moves, the second first candidate 31 located in the center of the first candidate group is It is selected as the _NH3 gas inlet. The etching apparatus 10, for example, switches the opening and closing of a valve located between the NH ₃ gas supply section 23 and the NH ₃ gas introduction port that is the supply destination to select the first one located on the leftmost side of the first candidate group. The first candidate 31 is selected as the NH ₃ gas inlet. Thereby, the NH ₃ gas inlet is moved from the position before movement to the position after movement.

Note that the etching apparatus 10 switches between the leftmost first candidate 31 and the first candidate 31 of the first candidate group by switching the valve located between the _NH3 gas supply unit 23 and the _NH3 gas inlet that is the supply destination. , and the first candidate 31 located in the center may be selected as the NH ₃ gas inlet. Thereby, it is possible to change the position of the NH ₃ gas introduction port and also change the number of NH ₃ gas introduction ports.

The etching apparatus 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 the same as 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 may switch the NH ₃ gas supply unit 23 for supplying the NH ₃ gas to the processing chamber 11, for example. Thereby, the etching apparatus 10 can move the NH ₃ gas inlet from the position before movement to the position after movement. The etching apparatus 10 connects an NH 3 gas supply unit 23 connected to the leftmost first candidate 31 of the first candidate group to an NH ₃ gas supply unit 23 connected to the rightmost first candidate 31 of the first candidate group. By switching to the NH ₃ gas supply section 23, the position of the NH ₃ gas inlet may be changed.

Alternatively, the etching apparatus 10 includes an NH ₃ gas supply unit 23 connected to the leftmost first candidate 31 of the first candidate group, and an NH ₃ gas supply unit 23 connected to the rightmost first candidate 31. NH ₃ gas may be supplied from both. As a result, the two first candidates 31 are each selected as the NH ₃ gas introduction port. As a result, it is also possible to change the position of the NH ₃ gas inlet and also change the number of NH ₃ gas inlets.

In this case, when only the NH ₃ gas inlet is set as the target port, the etching apparatus 10 controls the flow rate of NH ₃ gas supplied from the target port to each target port _. Each section 23 is provided with one section 23. Since one NH ₃ gas supply section 23 is provided for one NH ₃ gas introduction port, it is possible to increase the degree of freedom in combining the flow rates of gases supplied from each NH ₃ gas introduction port.

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 port. For example, before controlling the flow rate, the flow rate of _NH3 gas introduced from the leftmost NH3 gas inlet is set to flow rate A, and the flow rate of _NH3 gas introduced from the rightmost _NH3 gas inlet is set to _flow rate A. When the flow rate is set to flow rate B, the total flow rate of 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 the NH ₃ gas connected to the rightmost NH 3 gas inlet is changed to the flow rate (A-α). The set value in the supply unit 23 may be changed to the flow rate (B+α).

Note that, for example, by setting in advance a predetermined conductance in the branched gas flow path connected to each target port, the flow rate ratio of the NH ₃ gas introduced from each target port can be set. Moreover, 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. This makes it possible to change the distribution of the etching amount within the plane of the substrate S.
Alternatively, the etching apparatus 10 causes two NH ₃ gas supply units 23 to supply NH ₃ gas, and one NH ₃ gas supply unit 23 supplies NH ₃ gas to the two first candidates 31. You may. Thereby, the etching apparatus 10 can introduce NH ₃ gas into the processing chamber 11 from 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, for the HF gas inlet which is one of the target ports, the second candidate 32 in the center of the second candidate group is selected as the HF gas inlet before the target port is moved. has been done. For example, the etching apparatus 10 selects the second candidate located on the leftmost side of the second candidate group by switching the opening/closing of a valve located between the HF gas supply unit 24 and the HF gas inlet that is the supply destination. 32 is selected as the HF gas inlet. As a result, the HF gas inlet is moved from the position before movement to the position after movement.

Note that the etching apparatus 10 controls both of the two second candidates 32 of 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 destination. It may also be selected as a gas inlet. Thereby, it is possible to change the position of the HF gas inlet and also change the number of HF gas inlets.

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

[Etching method]
The etching method will be described with reference to FIGS. 5 to 8.
FIG. 5 is a timing chart 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, the control unit 10C first drives the NH ₃ gas supply unit 23, the N ₂ gas supply unit 21, and the HF gas supply unit 24. (timing t1). As a result, the NH ₃ gas supply unit 23 starts supplying NH ₃ gas, so that NH ₃ gas is introduced from the first candidate 31 selected as the NH ₃ gas introduction port. Further, the HF gas supply unit 24 starts supplying HF gas, and thereby HF gas is introduced from the second candidate 32 selected as the HF gas introduction port. Further, the N ₂ gas supply unit 21 starts supplying N ₂ gas, and thereby, N ₂ gas is introduced from the N ₂ gas introduction port 33 .

After the supply of each gas is continued until a predetermined period elapses from timing t1, 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 (timing t2). As a result, the NH ₃ gas supply unit 23 stops supplying NH ₃ gas, so the introduction of NH ₃ gas is stopped. Further, the HF gas supply unit 24 stops supplying HF gas, thereby stopping the introduction of HF gas. Further, the N ₂ gas supply unit 21 stops supplying N ₂ gas, thereby stopping the introduction of N ₂ gas.

After a predetermined period has elapsed from timing t2, the control unit 10C controls the driving of the NH ₃ gas supply unit 22, the N ₂ gas supply unit 21, and 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 introduction port 33 .

Further, the NF ₃ gas supply unit 25 is connected to the gas dispersion tube 11C, whereby NF ₃ gas is introduced into the processing chamber 11 from the NF ₃ gas introduction port 34 . Alternatively, the NF ₃ gas supply unit 25 may be connected to the shower head 11D, whereby NF ₃ gas may be introduced into the processing chamber 11 from at least one of the first candidate 31 and the second candidate 32.

As a result, the NH ₃ gas supply unit 22 starts supplying NH ₃ gas, and the N ₂ gas supply unit 21 supplies N ₂ gas, so that the mixed gas of NH ₃ gas and N ₂ gas is It is supplied to the discharge tube 26. Furthermore, since the NF ₃ gas supply unit 25 starts supplying NF ₃ gas, NF ₃ gas is introduced from the gas introduction port 34 of the gas distribution tube 11C.

After a predetermined period has elapsed from timing t3, the control unit 10C controls the driving of the microwave source 28 (timing t4). As a result, the microwave source 28 oscillates microwaves, and the microwaves are irradiated onto the discharge tube 26 through the waveguide 27, thereby generating plasma from the above-mentioned mixed gas. The plasma generated from the mixed gas contains hydrogen radicals (H ^* ), which are an example of excited species. Therefore, after timing t4, H ^* is introduced from the N ₂ gas introduction port 33.

After a predetermined period has elapsed from timing t4, the control unit 10C controls the driving of the NH ₃ gas supply unit 22, the N ₂ gas supply unit 21, the NF ₃ gas supply unit 25, and the microwave source 28. (timing t5). As a result, the NH ₃ gas supply unit 22 stops supplying NH ₃ gas, so the introduction of NH ₃ gas is stopped. Further, the NF ₃ gas supply unit 25 stops supplying NF ₃ gas, thereby stopping the introduction of NF ₃ gas. Further, the N ₂ gas supply unit 21 stops supplying N ₂ gas, thereby stopping the introduction of N ₂ gas. Additionally, the microwave source 28 stops oscillating microwaves.

6 to 8 show the states of the first processing target and the second processing target included in the substrate S for each step included in the etching method. Note that FIG. 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.

As shown in FIG. 6, an 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. 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 . The silicon oxide layer 53 is, for example, a natural oxide film formed by exposing the silicon layer 52 to the atmosphere. Silicon layer 52 is made of polysilicon. A modified silicon layer 52A is located on the surface of the silicon layer 52 that is in contact with the silicon oxide layer 53. The modified silicon layer 52A is not a layer formed from silicon oxide, but is a portion of the silicon layer 52 that has been modified by oxygen in the atmosphere by being exposed to the atmosphere.

At timing t1, NH ₃ gas and HF gas are introduced into the processing chamber 11. As a result, the first etchant E1 is generated in the processing chamber 11 from the NH ₃ gas and the HF gas. The silicon oxide layer 53 is etched by supplying the first etchant E1 to the substrate S from timing t1 to timing t2. Thus, 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, before the first step, a changing step of changing the distance between the center SC of the substrate S and the target hole by changing the position of the target hole. Thereby, it is possible to change the distribution of the etching amount within the plane of the substrate S.

Further, the etching method may include, before the first step, a setting step of independently setting the flow rate of gas supplied from each target port in the plurality of target ports. Thereby, it is possible to set the flow rate of gas supplied from each target port. Therefore, it is possible to change the flow rate of gas introduced from one target port, or change the ratio of the flow rate of gas supplied from the first target port to the flow rate of the gas supplied from the second target port. It is possible to change the etching distribution within the plane of the substrate S by, for example, changing the etching distribution within the plane of the substrate S.

Note that in the setting step, the flow rate of gas introduced from each target port may be changed. Thereby, the flow rate of gas introduced from the target port is changed without changing the total flow rate of gas introduced into the processing chamber 11. Therefore, it is possible to change the gas distribution within the plane of the substrate S while suppressing pressure fluctuations within the processing chamber 11. This makes it possible to change the distribution of the etching amount within the plane of the substrate S.

As shown in FIG. 7, at timing t4, excited species in the plasma generated from a mixed gas of NH ₃ gas and N ₂ gas and NF ₃ gas are introduced into the processing chamber 11, and thereby the excited species A second etchant E2 is generated from the etchant and the NF ₃ gas. 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 second etchant E2 is supplied to the substrate S until timing t5, thereby etching the modified silicon layer 52A. In this way, the period from timing t4 to timing t5 described above is the second step in which the modified silicon layer 52A, which is a part of the silicon layer 52, is etched.

Note that after timing t5, at least a reaction product containing silicon generated by the reaction of the second etchant E2 with the modified silicon layer 52A is located on the silicon layer 52. Therefore, the reaction product on the silicon layer 52 is volatilized by heating the substrate S, which has been subjected to the treatment in the first step and the treatment in the second step, by the first heating unit 11A.

[Effect]
The etching method and the operation of the etching apparatus will be described with reference to FIGS. 9 to 12. FIG. 9 shows the selectivity of silicon oxide layer 53 to silicon layer 52. The selectivity is the ratio of the amount of etching of the silicon oxide layer 53 to the amount of etching of the silicon layer 52. FIG. 10 shows the selectivity of silicon oxide layer 53 to silicon nitride layer 51. The selectivity is the ratio of the amount of etching of the silicon oxide layer 53 to the amount of etching of the silicon nitride layer 51.

When using excited species that are difficult to maintain in an activated state, variations occur in the supply amount of the activated excited species between multiple substrates S, and due to this, the etching amount between the substrates S varies. Variations will occur. In this regard, according to the first step of the present disclosure, since NH ₃ gas and HF gas are used to generate the first etchant E1, the first etchant between the substrates S is Variations in the amount of etchant E1 produced are less likely to occur. Therefore, variations in the amount of etching between the substrates S can be suppressed.

Moreover, as shown in FIG. 9, when the first step is carried out under an example of etching conditions, the selectivity ratio of the silicon oxide layer 53 to the silicon layer 52 is 107.1 in the first step. It is being On the other hand, when the second step is carried out under one example of etching conditions, it is recognized that the selectivity ratio of the silicon oxide layer 53 to the silicon layer 52 is 5.0 in the second step.

On the other hand, as shown in FIG. 10, when the first step is performed under an example of etching conditions, the selectivity ratio of the silicon oxide layer 53 to the silicon nitride layer 51 is 52.5 in the first step. It is recognized that On the other hand, when the second step is performed under one example of etching conditions, it is recognized that the selectivity ratio of the silicon oxide layer 53 to the silicon nitride layer 51 is 3.9 in the second step. .

In this way, regardless of whether the second etching target is the silicon layer 52 or the silicon nitride layer 51, according to the first process, the second etching target is the silicon oxide layer 53, which is the first process target. It is possible to obtain a higher selectivity compared to Further, according to the second step, it is also possible to etch both the first processing target and the second processing target.

FIG. 11 shows the 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 a silicon oxide layer having a uniform thickness over the entire surface is used as an etching target. FIG. 11 shows the etching amount from the center of the substrate to a position 147 mm away in the radial direction of the substrate.

In addition, in FIG. 11, the distance between the inlets, which is the distance between the NH ₃ gas inlet and the HF gas inlet when viewed from a viewpoint facing the plane on which the substrate spreads, is the first distance, the second distance, and the second distance. It has been changed to 3 ways with 3 distances. From the first distance to the third distance, the first distance is the shortest and the third distance is the longest. In FIG. 11, the amount of etching when the distance between the introduction ports is set to the first distance is shown by a broken line. Further, the amount of etching when the distance between the introduction ports is set to the second distance is shown by a solid line. Further, the amount of etching when the distance between the introduction ports is set to the third distance is shown by a chain line. Note that when changing the distance between the inlets, both the position of the NH ₃ gas inlet and the position of the HF gas inlet in the processing chamber 11 are changed.

As shown in FIG. 11, when the distance between the inlets is set to the first distance, the amount of etching is the smallest at the center of the substrate, and the amount of etching increases as the distance from the center of the substrate increases. Admitted. Furthermore, it was found that when the absolute values of the distances from the center of the substrate were equal, the etching amounts were also equal. That is, when the distance between the introduction ports was set to the first distance, it was observed that the graph showing the relationship between the etching amount and the position on the substrate had a downwardly convex shape.

It was found that when the distance between the introduction ports was set to the second distance, the amount of etching was greatest at the center of the substrate, and that the amount of etching decreased as the distance from the center of the substrate increased. Furthermore, it was found that when the absolute values of the distances from the center of the substrate were equal, the etching amounts were also equal. That is, when the distance between the inlets was set to the second distance, it was observed that the graph showing the relationship between the etching amount and the position on the substrate had an upwardly convex shape.

When the distance between the inlets is set to the third distance, the graph showing the relationship between the etching amount and the position on the substrate is convex upwards, similar to when the distance between the inlets is set to the second distance. It was recognized that the patient had a condition. However, it was found that the maximum value of the etching amount when the third distance was set was greater than the maximum value of the etching amount when the second distance was set. Furthermore, it was found that the minimum value of the etching amount when the third distance was set was smaller than the minimum value of the etching amount when the second distance was set.

In this way, 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, it is possible to change the etching amount distribution within the plane of the substrate.

FIG. 12 is a graph showing the relationship between the distance between introduction ports and the etching amount ratio for six cases in which only the distance between introduction ports was changed in the same etching process as shown in FIG. 11. Note that the etching amount ratio in FIG. 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. Therefore, when the etching amount ratio is smaller than 1, the graph showing the relationship between the etching amount and the position on the substrate shows a downward convex shape, whereas when the etching amount ratio is larger than 1, A graph showing the relationship between the etching amount and the position on the substrate shows an upwardly convex shape.

As shown in FIG. 12, under one example of the etching conditions, it was observed that the etching amount ratio was smaller than 1 in a range where the distance between the inlets was 25 mm or less. On the other hand, it was observed that the etching amount ratio was greater than 1 in a range where the distance between the inlets was 30 mm or more. In this way, by changing the distance between the inlets, that is, the distance between the inlet and the center of the substrate, it is possible to adjust the amount of etching in the plane of the substrate.

As explained above, according to one embodiment of the etching method and etching apparatus, the following effects can be obtained.
(1) In the first step, the first processing target is etched using NH ₃ gas and HF gas, so compared to the case where etching is performed using plasma in both the first step and the second step, The etching amount is less likely to be distributed between the substrates S.

(2) By changing the distance between the target opening and the center SC of the substrate S, it is possible to change the distribution of the etching amount within the plane of the substrate S.
(3) It is possible to set the flow rate of gas supplied from each target port. Therefore, it is possible to change the flow rate of gas introduced from one target port, or change the ratio of the flow rate of gas supplied from the first target port to the flow rate of the gas supplied from the second target port. It is possible to change the etching distribution within the plane of the substrate S by, for example, changing the etching distribution within the plane of the substrate S.

(4) Since the flow rate of gas introduced into the processing chamber 11 from the target port is changed, it is possible to change the gas distribution within the plane of the substrate S. This makes it possible to change the distribution of the etching amount within the plane of the substrate S. In particular, by setting a predetermined conductance in advance in the branched gas flow path connected to each target port, the flow rate of the gas supplied from each target port can be combined without having to provide a flow rate control unit for all the target ports. can be changed.

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

(6) Since one supply section 23, 24 is provided for one target port, it is possible to increase the degree of freedom in combining the flow rates of gases supplied from each target port.
Note that the above-described embodiment may be modified and implemented as follows.

[Target mouth]
- In the etching apparatus 10, only one of the NH ₃ gas introduction port and the HF gas introduction port may be the target port. For example, when the NH ₃ gas introduction port is the target port, the position of the HF gas introduction port in the processing chamber 11 is fixed. On the other hand, when the HF gas inlet is the target port, the position of the NH ₃ inlet in the processing chamber 11 is fixed.

- A change operation for changing the target opening from the first candidate to the second candidate may be performed by the user of the etching apparatus 10. The changing 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.

[Flow rate control section]
- 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 and a second conductance. The first conductance is different from the second conductance. In this case, even if the setting values in the NH ₃ gas supply unit 23 are the same, the NH ₃ gas supply unit 23 selects a pipe having the first conductance as the pipe for supplying NH ₃ gas. , it is possible to change the flow rate of NH ₃ gas depending on the case where the pipe having the second conductance 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 the first conductance and a pipe having the first conductance. , and piping having a second conductance. The first conductance is different from the second conductance. In this case, even if the setting values in the HF gas supply section 24 are the same, the case where the HF gas supply section 24 selects the pipe having the first conductance as the pipe for supplying HF gas, and the case where the pipe with the second conductance is selected as the pipe for supplying the HF gas. It is possible to change the flow rate of HF gas depending on the case where a pipe having a conductance of .

[Moving mechanism]
- As shown in FIG. 13, 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 arranged in the processing chamber 11 at a position facing the exhaust section 11B. The first moving mechanism 41 includes a first rotating section 41A, a first nozzle 41B, and an 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 rotating section 41A is configured to be capable of rotation, that is, rotational movement, about a rotation axis extending along a direction parallel to the direction in which the processing chamber 11 extends. The first nozzle 41B is connected to the first rotating section 41A. The NH ₃ gas inlet 41C is located at the tip of the first nozzle 41B. The NH ₃ gas supply section 23 is connected to the first rotating section 41A. NH ₃ gas is supplied to the NH ₃ gas inlet 41C through the first rotating portion 41A and the first nozzle 41B.

The second moving mechanism 42 includes a second rotating section 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 installed in the processing chamber 11. The second rotating section 42A is configured to be capable of rotation, that is, rotational movement, about a rotation axis extending in a direction parallel to the direction in which the processing chamber 11 extends. The second nozzle 42B is connected to the second rotating section 42A. The NHF gas inlet 42C is located at the tip of the second nozzle 42B. The HF gas supply section 24 is connected to the second rotating section 42A. HF gas is supplied to the HF gas inlet 42C through the second rotating section 42A and the second nozzle 42B.

The NH ₃ gas introduction port 41C is an example of a first gas introduction port, and the HF gas introduction port 42C is an example of a second gas introduction port. The NH ₃ gas introduction port 41C and the HF gas introduction port 42C are each located on a straight line parallel to the normal line of the substrate S. The NH ₃ gas introduction port 41C is configured such that the flow direction of the NH ₃ gas introduced from the NH ₃ gas introduction port 41C is parallel to the plane in 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 in which the substrate S spreads, and parallel to the flow direction of the NH ₃ gas. There is.

By at least one of the first moving mechanism 41 rotating the first rotating part 41A and the second moving mechanism 42 rotating the second rotating part 42A, the _NH3 gas inlet 41C and the HF gas inlet 42C It is possible to change the distance between Further, by the first moving mechanism 41 rotating the first rotating section 41A, it is possible to change the angle at which the NH ₃ gas is introduced to the substrate S. Further, by the second moving mechanism 42 rotating the second rotating section 42A, it is possible to change the angle at which the HF gas is introduced to the substrate S.

Further, according to the first moving mechanism 41, the distance between the NH ₃ gas introduction port 41C and the center SC of the substrate S can be changed by rotating the first rotating portion 41A. According to the second moving mechanism 42, the distance between the HF gas inlet 42C and the center SC of the substrate S can be changed by rotating the second rotating part 42A. According to the etching apparatus 10, by using at least one of the first moving mechanism 41 and the second moving mechanism 42, it is possible to change the etching amount distribution within the plane of the substrate S.

Note that the amount of rotation of each of the rotating parts 41A and 42A, that is, the position of the introduction ports 41C and 42C in the processing chamber 11, may be changed by the control part 10C or by the user of the etching apparatus 10. Good too.

[First step]
- In the first step, the entire silicon oxide layer 53 may be removed, or a portion of the silicon oxide layer 53 may be left on the substrate S. Note that if a part of the silicon oxide layer 53 is left on the substrate S in the first step, a part of the silicon oxide layer 53 is left on the substrate S in the second step together with the silicon layer 52 or the silicon nitride layer 51. May be removed.

- The first step may be performed after the second step.

DESCRIPTION OF SYMBOLS 10... Etching apparatus 11... Processing chamber 21... _N2 gas supply part 22, 23... _NH3 gas supply part 24... HF gas supply part 25... _NF3 gas supply part 26... Discharge tube 27... Waveguide 28... Microwave source

Claims (18)

Each of the plurality of substrates housed in the vacuum chamber 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 with 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;
After the first step, a second step of etching the second processing target by supplying plasma generated from a gas containing _NH gas and _NF gas to the vacuum chamber ,
At least one of the NH ₃ gas introduction port for introducing NH ₃ gas into the vacuum chamber and the HF gas introduction port for introducing HF gas into the vacuum chamber is a target port,
Before the first step, the method includes a changing step of changing the distance between the center of the substrate and the target opening by changing the position of the target opening.
Etching method. Each of the plurality of substrates housed in the vacuum chamber 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 with 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;
After the first step, a second step of etching the second processing target by supplying plasma generated from a gas containing NH gas and NF _{gas to} the vacuum chamber,
Either one of the NH ₃ gas introduction port for introducing NH ₃ gas into the substrate and the HF gas introduction port for introducing HF gas into the substrate is a target port,
Prior to the first step, the method includes a setting step of independently setting the flow rate of gas supplied from each target port in the plurality of target ports.
Etching method. The etching method according to claim 2 , wherein in the setting step, the flow rate of the gas introduced from each target port is changed by setting in advance the conductance of the gas flow path of the gas introduced from the target port. The 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 with the silicon oxide layer,
a vacuum chamber accommodating a plurality of the substrates;
a first processing section that etches the first processing target by introducing NH ₃ gas and HF gas into the vacuum chamber;
a second processing section that etches the second processing object by introducing plasma generated from a gas containing NH ₃ gas and NF ₃ gas into the vacuum chamber after the processing with the first processing object; An etching apparatus comprising:
an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber ;
an HF gas inlet for introducing HF gas into the vacuum chamber,
At least one of the NH ₃ gas introduction port and the HF gas introduction port is a target port,
The etching apparatus includes a plurality of candidates for the target opening,
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.
Etching equipment. The 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 with the silicon oxide layer,
a vacuum chamber accommodating a plurality of the substrates;
a first processing section that etches the first processing target by introducing NH ₃ gas and HF gas into the vacuum chamber;
a second processing section that etches the second processing object by introducing plasma generated from a gas containing NH ₃ gas and NF ₃ gas into the vacuum chamber after the processing with the first processing object; An etching apparatus comprising:
an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber;
an HF gas inlet for introducing HF gas into the vacuum chamber,
At least one of the NH ₃ gas introduction port and the HF gas introduction port is a target port,
The etching apparatus further includes a moving mechanism that moves the target opening so as to change the distance between the center of the substrate and the target opening.
Etching equipment. The 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 with the silicon oxide layer,
a vacuum chamber accommodating a plurality of the substrates;
a first processing section that etches the first processing target by introducing NH ₃ gas and HF gas into the vacuum chamber;
a second processing section that etches the second processing object by introducing plasma generated from a gas containing NH ₃ gas and NF ₃ gas into the vacuum chamber after the processing with the first processing object; An etching apparatus comprising:
an NH ₃ gas inlet for introducing NH ₃ gas into the vacuum chamber;
an HF gas inlet for introducing HF gas into the vacuum chamber,
Either one of the NH ₃ gas introduction port and the HF gas introduction port is a target port,
The etching apparatus includes a plurality of the target openings,
The etching apparatus includes one flow rate control unit that controls the flow rate of gas supplied from each target port to each target port.
Etching equipment. The flow rate control unit controls the flow rate of the gas so as to maintain the total flow rate of the gas introduced from all the target ports and change the flow rate of the gas introduced from each target port . etching equipment. a vacuum chamber that accommodates multiple substrates;
a first gas introduction port for introducing NH ₃ gas into the vacuum chamber;
a second gas introduction port for introducing HF gas into the vacuum chamber;
a mechanism for changing the distance between the first gas inlet and the second gas inlet ,
a _third gas inlet for introducing NF3 gas ;
Further comprising a fourth gas inlet for introducing NH3 gas discharged _through the discharge tube.
Etching equipment. a vacuum chamber that accommodates multiple substrates;
a first gas introduction port for introducing NH ₃ gas into the vacuum chamber ;
a second gas introduction port for introducing HF gas into the vacuum chamber;
a mechanism for changing the distance between the first gas inlet and the second gas inlet,
NH ₃ gas introduced from one flow path is branched to two or more of the first gas introduction ports, and
HF gas introduced from one flow path is branched to two or more of the second gas introduction ports,
Equipped with a mechanism that changes the _distance between the target port of the _NH3 gas inlet and the target port of the HF gas inlet by selecting the branch of NH3 gas and HF gas.
Etching equipment. _NH3 gas introduced from one channel is branched into channels having different conductances, and
The etching apparatus according to claim 9 , wherein the HF gas introduced from one channel is branched into channels having different conductances. a vacuum chamber that accommodates multiple substrates;
a first gas introduction port for introducing NH ₃ gas into the vacuum chamber ;
a second gas introduction port for introducing HF gas into the vacuum chamber;
a mechanism for changing the distance between the first gas inlet and the second gas inlet,
NH ₃ gas introduced from one flow path is branched to two or more of the first gas introduction ports, and
HF gas introduced from one flow path is branched to two or more of the second gas introduction ports,
Each branched flow path is provided with one flow control section.
Etching equipment. The first gas introduction port and the second gas introduction port are arranged parallel to a normal line of the substrate and on a straight line, and further, the gas introduced is parallel to the substrate and parallel to each other. provided, and
The first gas inlet and the second gas inlet are attached to an axis parallel to the normal line of the substrate installed in the vacuum chamber, and the first gas inlet and the second gas inlet are provided with a mechanism for rotating around the axis. Item 8. Etching apparatus according to item 8 . Regarding multiple substrates housed in a vacuum chamber,
A first process performed by introducing NH ₃ gas and HF gas into the vacuum chamber;
a second process performed by supplying plasma generated from a gas containing _NH3 gas and _NF3 gas to the vacuum chamber ,
In the first process, the NH ₃ gas introduced from one flow path is branched to two or more first gas introduction ports, and
HF gas introduced from one flow path is branched to two or more second gas introduction ports,
By selecting the branch of NH3 gas and _HF gas, change the distance between the target port of the NH3 gas inlet and the target port of the HF gas inlet _.
Etching method. The target of the first treatment is a silicon oxide layer,
The etching method according to claim 13 , wherein the target of the second treatment is a silicon nitride layer or a silicon layer covered with the silicon oxide layer. The etching method according to claim 14 , wherein the second treatment is performed after the first treatment. _NH3 gas introduced from one channel is branched into channels having different conductances, and
HF gas introduced from one channel is branched into channels with different conductances,
The etching method according to claim 13 , wherein NH ₃ gas and HF gas are introduced from the first gas introduction port and the second gas introduction port at different flow rates. Regarding multiple substrates housed in a vacuum chamber,
A first process performed by introducing NH ₃ gas and HF gas into the vacuum chamber;
a second process performed by supplying plasma generated from a gas containing NH3 gas and _{NF3 gas} to the vacuum chamber,
In the first process, the NH ₃ gas introduced from one flow path is branched to two or more first gas introduction ports, and
HF gas introduced from one flow path is branched to two or more second gas introduction ports,
The flow control units provided in each of the branched flow paths control the target ports for NH ₃ gas and HF gas at different flow rates and different distances from the first gas inlet and the second gas inlet. Introduced from the introduction port
Etching method. Regarding multiple substrates housed in a vacuum chamber,
A first process performed by introducing NH ₃ gas and HF gas into the vacuum chamber;
a second process performed by supplying plasma generated from a gas containing NH3 gas and _{NF3 gas} to the vacuum chamber,
In the first process, the gas is arranged parallel to the normal line of the substrate and on a straight line, and further provided so that the gases introduced are parallel to the substrate and parallel to each other, and in the vacuum chamber. From a first gas introduction port and a second gas introduction port attached to an axis parallel to the normal line of the installed substrate, each introduction port is rotated about the axis to introduce the first gas. After setting the distance and introduction angle between the port and the second gas introduction port, _NH3 gas and HF gas are introduced.
Etching method.

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