JP2024089558A - Semiconductor device manufacturing method and semiconductor manufacturing device - Google Patents

Abstract

To provide a method for manufacturing a semiconductor device capable of successfully performing selective etching for a layer to be etched, and a manufacturing device thereof.SOLUTION: A method for manufacturing a semiconductor device includes processing of a substrate including a laminate in which a layer to be protected and a layer to be etched are alternately laminated. The method includes a step of selectively forming a self-assembled monolayer (SAM) on at least a surface of the layer to be protected, and a step of selectively etching the layer to be etched with the SAM as a protection layer. The SAM forming step includes a first contact step, a removal step, a surface modification step, and a second contact step. The first contact step chemically absorbs a SAM molecule by bringing a first process liquid containing the SAM molecule into contact with a surface of the layer to be protected. The removal step removes a SAM molecule which has not been chemically absorbed from the surface of the layer to be protected. The surface modification step surface-modifies a region in which no SAM molecule exists on the surface of the layer to be protected after the removal step into a region which can be chemically absorbed by a SAM molecule. The second contact step chemically absorbs the SAM molecule by bringing a second process liquid containing the SAM molecule and having the same kind or a different kind of the first process liquid into contact with the surface-modified region.SELECTED DRAWING: Figure 3

Description

The present invention relates to a semiconductor device manufacturing method and semiconductor manufacturing apparatus that can selectively etch a layer to be etched by forming a self-assembled monolayer with excellent density and protective performance as a protective layer.

NAND flash memory is known as a device capable of storing data in a non-volatile manner. For example, one example of this type of NAND flash memory is a three-dimensional NAND flash memory in which memory cells are stacked vertically on a substrate.

And in a 3D NAND structure such as a 3D NAND flash memory, the etching process is required not only to form a recess with a relatively wide opening, but also to form a recess with a narrow opening and a deep shape in the film thickness direction.

As such an etching process, for example, in the case of a substrate having a silicon nitride (SiN) film and a silicon oxide (SiO ₂ ) film provided on its surface, the silicon nitride film may be etched by a wet etching method using phosphoric acid (H ₃ PO ₄ ) as a processing liquid (etching liquid) (Patent Document 1). However, when the silicon (Si) concentration in the processing liquid is high, the etching rate is so fast that the replacement rate of the processing liquid in the 3D NAND structure cannot keep up, and the etched silicon components precipitate and adhere to the surface of the silicon oxide film. In addition, when the silicon concentration in the processing liquid is low, there is also a problem that the etching selectivity decreases and the silicon oxide film is etched.

JP 2021-027125 A

The present invention has been made in consideration of the above problems, and its purpose is to provide a semiconductor device manufacturing method and semiconductor manufacturing apparatus that can perform good selective etching of the layer to be etched by forming a self-assembled monolayer with excellent density and protective performance as a protective layer.

In order to solve the above-mentioned problems, the manufacturing method of the semiconductor device according to the present invention is a manufacturing method of a semiconductor device including processing a substrate having a laminate on its surface, the laminate including an alternately laminated protected layer to be protected by etching and an etched layer to be etched, the method including a step of selectively forming a self-assembled monolayer on at least the surface of the protected layer, and a step of selectively etching the etched layer using the self-assembled monolayer as a protective layer, the step of forming the self-assembled monolayer including a first contact step of contacting a first treatment liquid containing molecules capable of forming the self-assembled monolayer with the surface of the protected layer to chemically adsorb the molecules, a removal step of removing the molecules that are not chemically adsorbed from the surface of the protected layer, a surface modification step of surface-modifying a region on the surface of the protected layer after the removal step where the molecules are not present into a region capable of chemical adsorption by the molecules, and a second contact step of contacting the surface-modified region with a second treatment liquid containing the molecules and the same or different type as the first treatment liquid to chemically adsorb the molecules.

The manufacturing method of the semiconductor device having the above-mentioned configuration is intended to form a self-assembled monolayer (hereinafter sometimes referred to as "SAM") on at least the surface of the layer to be protected when etching the layer to be etched, thereby improving the selective etching performance of the layer to be etched. In the above-mentioned configuration, the SAM formation process sequentially performs the following steps. That is, first, in the first contact step, molecules capable of forming a SAM (hereinafter sometimes referred to as "SAM molecules") are chemically adsorbed to the surface of the substrate, and then, in the removal step, the SAM molecules that are not chemically adsorbed are removed. This prevents the surface modification of the area where the SAM molecules could not be chemically adsorbed from being inhibited. Furthermore, in the surface modification step, surface modification is performed on the area where the SAM molecules can be chemically adsorbed, and in the second contact step, the SAM molecules are chemically adsorbed to the surface-modified area.

In this configuration, the area where the SAM molecules could not be chemisorbed in the first contact step is surface-modified to enable chemisorption of the SAM molecules, and then the SAM molecules are chemisorbed again, so that it is possible to reduce the need for the SAM molecules to be in contact with the substrate surface for a long period of time to form a dense SAM, as in conventional methods. As a result, it is possible to suppress the occurrence of film defects and efficiently form a SAM with excellent density and protective performance in a short period of time. Furthermore, by forming a SAM with excellent density and protective performance as a protective layer on at least the surface of the layer to be protected, selective etching of the layer to be protected can be performed well.

In the above configuration, the method may further include a step of etching the layer to be etched to a predetermined depth in the film thickness direction immediately before the step of forming the self-assembled monolayer, and the step of forming the self-assembled monolayer may be a step of forming the self-assembled monolayer also on the side surface of the protected layer that is exposed by etching the layer to be etched.

In cases where the layer to be etched is etched in advance to a predetermined depth in the thickness direction, the side of the layer to be protected is exposed to the extent that the layer to be etched is etched away. However, with the above-described configuration, even in such cases, a SAM is formed not only on the surface of the layer to be protected, but also on the exposed side, allowing the layer to be selectively etched well while protecting it.

In the above configuration, the second contact step is preferably a step of chemically adsorbing the molecules to the area surface-modified in the surface modification step, thereby performing a densification process on the self-assembled monolayer formed in the first contact step.

According to the above-mentioned configuration, after the SAM is formed in the first contact step, the SAM molecules that are not chemically adsorbed on the surface of the substrate are removed in the removal step, and the surface is modified so that the SAM molecules can be chemically adsorbed in the area where the SAM molecules are not present. Then, in the second contact step, the second processing liquid containing the SAM molecules is brought into contact with the area where the SAM molecules are not present. Here, in the SAM formed in the first contact step, the SAM molecules may not be chemically adsorbed locally on the surface of the substrate, resulting in film defects. However, in the above-mentioned configuration, after the SAM is formed in the first contact step, the SAM molecules that are not chemically adsorbed are removed from the area where the film defects are occurring, and the surface is modified, so that the SAM molecules are chemically adsorbed in the area where the film defects are occurring, thereby improving or improving the denseness of the SAM. As a result, unlike the conventional SAM film formation method, it is not necessary to keep the SAM molecules in contact with the substrate surface for a long time, and a SAM with excellent denseness and protective performance can be efficiently formed in a short time. Furthermore, by forming a SAM with excellent density and protective performance as a protective layer on at least the surface of the layer to be protected, selective etching of the layer to be protected can be performed well.

Furthermore, in the above-mentioned configuration, it is preferable that the protected layer is made of silicon dioxide, the etched layer is made of silicon nitride, the molecules have functional groups capable of forming siloxane bonds with hydroxyl groups, the surface modification in the surface modification step generates hydroxyl groups in areas where the molecules are not present, and the chemical adsorption of the molecules in the first contact step and the second contact step bonds the molecules to the surface via siloxane bonds with the hydroxyl groups on the surface of the protected layer.

According to the above-mentioned configuration, by performing surface modification on the layer to be protected made of silicon dioxide so that hydroxyl groups are generated at least on its surface, molecules having functional groups capable of forming siloxane bonds with hydroxyl groups can be chemically adsorbed onto the surface of the layer to be protected via the siloxane bonds.

In the above configuration, the surface modification step is a step of contacting a surface modification liquid with the area of the surface of the protected layer where the molecules are not present after the removal step, and the surface modification liquid may be a solution that generates hydroxyl groups on the surface of the protected layer made of silicon dioxide.

In the above configuration, the surface modification process may be at least one of the following processes: contacting an area on the surface of the protected layer where the molecules are not present with ozone gas, irradiating an area on the surface of the protected layer where the molecules are not present with ultraviolet light, and contacting an area on the surface of the protected layer where the molecules are not present with a gas containing moisture.

Furthermore, in the above configuration, it is preferable that the molecule contains octadecyltrichlorosilane.

In order to solve the above-mentioned problems, the semiconductor manufacturing apparatus of the present invention is a semiconductor manufacturing apparatus that processes a substrate having a laminate on its surface, and the laminate includes a layer to be protected by etching and a layer to be etched that is to be etched that are alternately laminated. The apparatus includes a substrate processing unit that selectively forms a self-assembled monolayer on at least the surface of the layer to be protected, and an etching processing unit that selectively etches and removes the layer to be etched using the self-assembled monolayer as a protective layer. The substrate processing unit includes a supply unit that supplies a processing liquid containing molecules capable of forming the self-assembled monolayer to the surface of the substrate, a removal liquid supply unit that supplies a removal liquid to the surface after the processing liquid is supplied to remove the molecules that are not chemically adsorbed, and a surface modification unit that modifies the surface after the molecules are removed by the removal liquid supply unit to modify the area where the molecules are not present into an area where the molecules can be chemically adsorbed, and the supply unit also supplies the processing liquid to the surface of the substrate after the surface modification by the surface modification unit.

The semiconductor manufacturing apparatus of the above configuration includes at least a substrate processing unit that selectively forms a SAM on the layer to be protected, and an etching processing unit that selectively etches and removes the layer to be etched. Before etching the layer to be etched in the etching processing unit, the substrate processing unit forms a SAM on at least the surface of the layer to be protected to protect it, thereby enabling excellent selective etching of the layer to be etched. In the above configuration, the supply unit supplies a processing liquid containing SAM molecules to the surface of the substrate, thereby allowing the SAM molecules to be chemisorbed in the area where they can be chemisorbed. In addition, the removal liquid supply unit removes the SAM molecules that are not chemisorbed on the surface of the substrate, thereby allowing the area where the SAM molecules are not chemisorbed to be fully exposed. Furthermore, the surface modification unit performs surface modification on the area where the SAM molecules are not chemisorbed, thereby enabling the SAM molecules to be chemisorbed in that area.

In this configuration, the supply unit supplies the treatment liquid again to the surface-modified area, so that SAM molecules can be chemically adsorbed to the area, and compared to conventional semiconductor manufacturing equipment, it is possible to reduce the amount of time that the SAM molecules need to be in contact with the substrate surface to form a dense SAM. As a result, it is possible to suppress the occurrence of film defects and efficiently form a SAM with excellent denseness and protective performance in a short period of time. Furthermore, by forming a SAM with excellent denseness and protective performance as a protective layer on at least the surface of the layer to be protected, it is possible to provide a semiconductor manufacturing equipment that can perform selective etching of the layer to be etched well.

In the above configuration, the etching processing unit etches the layer to be etched to a predetermined depth in the film thickness direction immediately before the formation of the self-assembled monolayer, and the substrate processing unit may also form the self-assembled monolayer on the side of the layer to be protected that is exposed by etching the layer to be etched.

In cases where the etching processing unit preliminarily etches the layer to be etched to a predetermined depth in the film thickness direction, the surface of the layer to be protected is also exposed by etching the layer to be etched. However, with the above-described configuration, even in such cases, the substrate processing unit can form a SAM not only on the surface of the layer to be protected but also on the exposed side surface, allowing for good selective etching of the layer to be protected.

In the above configuration, the layer to be protected is made of silicon dioxide, the layer to be etched is made of silicon nitride, the molecules have functional groups capable of forming siloxane bonds with hydroxyl groups, the surface modification unit is a surface modification liquid supply unit that supplies a surface modification liquid to an area where the molecules are not present, and the surface modification liquid may be a solution that generates hydroxyl groups on the surface of the layer to be protected.

In the above configuration, the layer to be protected is made of silicon dioxide, the layer to be etched is made of silicon nitride, the molecules have functional groups capable of forming siloxane bonds with hydroxyl groups, and the surface modification unit may be at least one of an ozone gas supply unit that supplies ozone gas to areas on the surface of the layer to be protected where the molecules are not present, an ultraviolet irradiation unit that irradiates areas on the surface of the layer to be protected with ultraviolet light, and a gas supply unit that supplies a gas containing moisture to areas on the surface of the layer to be protected where the molecules are not present.

According to the present invention, by forming a self-assembled monolayer with excellent density and protective performance as a protective layer on at least the surface of the layer to be protected, it is possible to prevent the layer to be etched from being etched and the etched components from precipitating on the surface of the layer to be etched. As a result, according to the present invention, it is possible to provide a semiconductor device manufacturing method and a semiconductor manufacturing device that can effectively manufacture semiconductor devices such as those having a three-dimensional NAND structure by selectively etching the layer to be etched.

1A and 1B are cross-sectional views each showing a schematic representation of a laminate provided on a substrate, in which FIG. 1A shows a state before an etching step, and FIG. 1B shows a state after the etching step. 2(a) is a partial enlarged view of the portion surrounded by A in the laminate of FIG. 1(a), FIG. 2(b) is a partial enlarged view showing the state where a SAM has been formed on the surface of the _SiO2 layer, and FIG. 2(c) is a partial enlarged view of the portion surrounded by B in the laminate of FIG. 1(b), showing the state where the SiN layer has been etched. 2 is a flowchart showing an example of an overall flow of a method for manufacturing a semiconductor device according to a first embodiment of the present invention. FIG. 4( a ) is a schematic diagram showing how a first treatment liquid is supplied to the surface of a SiO ₂ layer in the first embodiment, FIG. 4( b ) is a schematic diagram showing how a SAM molecule is chemically adsorbed to the surface of the SiO ₂ layer, and FIG. 4( c ) is a schematic diagram showing how the SAM molecule is self-assembled on the surface of the SiO ₂ layer to form a SAM. FIG. 5(a) is a schematic diagram showing the state of the _SiO2 layer surface after removing unadsorbed SAM molecules and reverse micelles in the first embodiment, FIG. 5(b) is a schematic diagram showing the state where surface modification is performed in an area where no SAM molecules are present and hydroxyl groups are generated, and FIG. 5(c) is a schematic diagram showing the state where the SAM is densified. 1 is an explanatory diagram illustrating a schematic configuration of a substrate processing unit in a semiconductor manufacturing apparatus according to a first embodiment of the present invention. 1 is an explanatory diagram illustrating a schematic configuration of a processing liquid storage section provided in a supply section of a substrate processing unit in a semiconductor manufacturing apparatus according to a first embodiment of the present invention. FIG. 13 is an explanatory diagram showing a schematic configuration of another processing liquid storage section provided in a supply section of a substrate processing unit in the semiconductor manufacturing apparatus according to the first embodiment of the present invention. FIG. 1 is an explanatory diagram illustrating a schematic configuration of a removing liquid reservoir provided in a removing liquid supply part of a substrate processing unit in a semiconductor manufacturing apparatus according to a first embodiment of the present invention. FIG. 1 is an explanatory diagram illustrating a schematic configuration of a surface modification liquid reservoir provided in a surface modification liquid supply section of a substrate processing unit in a semiconductor manufacturing apparatus according to a first embodiment of the present invention. FIG. 1 is an explanatory diagram illustrating a schematic configuration of an etching processing unit in a semiconductor manufacturing apparatus according to a first embodiment of the present invention. 1 is an explanatory diagram illustrating a schematic configuration of an etching liquid reservoir provided in an etching liquid supply section of an etching processing unit in a semiconductor manufacturing apparatus according to a first embodiment of the present invention. FIG. 10 is a flowchart showing an example of an overall flow of a method for manufacturing a semiconductor device according to a second embodiment of the present invention. FIG. 14(a) is a partial enlarged view showing a state in which the SiN layer has been partially etched to a predetermined depth in the film thickness direction, FIG. 14(b) is a partial enlarged view showing a state in which a SAM has been formed on the surface of the _SiO2 layer, and FIG. 14(c) is a partial enlarged view showing a state in which the SiN layer has been etched. 13 is a flowchart showing an example of an overall flow of a method for manufacturing a semiconductor device according to a third embodiment of the present invention. FIG. 13 is an explanatory diagram illustrating a schematic configuration of a substrate processing unit in a semiconductor manufacturing apparatus according to a third embodiment of the present invention. 13 is a flowchart showing an example of an overall flow of a method for manufacturing a semiconductor device according to a fourth embodiment of the present invention. FIG. 13 is an explanatory diagram illustrating a schematic configuration of a substrate processing unit in a semiconductor manufacturing apparatus according to a fourth embodiment of the present invention.

First Embodiment
A method for manufacturing a semiconductor device and an apparatus for manufacturing a semiconductor device according to a first embodiment of the present invention will be described below.

[Method of Manufacturing Semiconductor Device]
First, a method for manufacturing a semiconductor device according to this embodiment will be described below with reference to the drawings.
The method for manufacturing a semiconductor device according to the present embodiment provides a technique that enables good selective etching when forming a three-dimensional structure such as a three-dimensional NAND structure on the surface of a substrate.

The method for manufacturing a semiconductor device according to this embodiment will be described below by taking as an example a portion of the process for forming a three-dimensional NAND structure on a substrate W made of silicon or the like. More specifically, the example will be a case in which processing is performed on a substrate W on which a three-dimensional stack 3 as shown in FIG. 1 is provided. FIG. 1 is a cross-sectional view that shows a schematic representation of the stack provided on the substrate W, where FIG. 1(a) shows the state before the etching process and FIG. 1(b) shows the state after the etching process.

2(a), the laminate 3 includes an _SiO2 layer 1 functioning as an interlayer insulating layer and an SiN layer 2 functioning as a sacrificial layer, which are alternately laminated on a substrate W. The laminate 3 also includes a plurality of memory trenches 4 extending through the laminate 3 in a direction perpendicular to the surface of the substrate W. Note that FIG. 2(a) is a partial enlarged view of a portion surrounded by A in the laminate in FIG.

As shown in FIG. 3, the method for manufacturing a semiconductor device according to this embodiment includes at least a self-assembled monolayer (hereinafter referred to as "SAM") formation step S1 and an etching step S2, and enables selective etching of the SiN layer 2 through the memory trench 4 to form a recess on the side of the memory trench 4 in the laminate 3. FIG. 3 is a flowchart showing an example of the overall flow of the method for manufacturing a semiconductor device according to this embodiment.

<SAM formation process>
The SAM formation step S1 is a step of selectively forming a SAM as a protective layer on the surface of the SiO ₂ layer 1, which is the layer to be protected. As shown in FIG. 3, the SAM formation step S1 includes at least a first contact step S101, a removal step S102, a surface modification step S103, a densification treatment step (second contact step) S104, and a rinsing step S105.

1. First Contact Step The first contact step S101 is a step of bringing a first processing liquid containing a material capable of forming a SAM (hereinafter referred to as "SAM-forming material") into contact with the surface of the substrate W to form a SAM.

The method of contacting the first processing liquid with the substrate W is not particularly limited, and examples include a method of applying the first processing liquid to the surface of the substrate W, a method of spraying the first processing liquid onto the surface of the substrate W, and a method of immersing the substrate W in the first processing liquid.

One method for applying the first processing liquid to the surface of the substrate W is, for example, to supply the first processing liquid to the center of the surface of the substrate W while the substrate W is rotated at a constant speed around its center as an axis. As a result, the first processing liquid supplied to the surface of the substrate W flows from near the center of the surface of the substrate W toward the peripheral edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the entire surface of the substrate W is covered with the first processing liquid, and a liquid film of the first processing liquid is formed.

The first treatment liquid contains at least a SAM-forming material. The first treatment liquid may contain the SAM-forming material dissolved or dispersed in a solvent. The SAM-forming material is not particularly limited, and examples thereof include organic silane compounds such as octadecyltrichlorosilane. Octadecyltrichlorosilane is a compound having a trichlorosilyl group as a functional group capable of forming a siloxane bond with a hydroxyl group. The solvent is not particularly limited, and examples thereof include ether solvents, aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, fluorine-based solvents, and the like. The ether solvent is not particularly limited, and examples thereof include tetrahydrofuran (THF), and the like. The aromatic hydrocarbon solvent is not particularly limited, and examples thereof include toluene, and the like. The aliphatic hydrocarbon solvent is not particularly limited, and examples thereof include decane, and the like. The fluorine-based solvent is not particularly limited, and examples thereof include 1,3-bis(trifluoromethyl)benzene, and the like. These solvents may be used alone or in a mixture of two or more. Among the solvents given as examples, aliphatic hydrocarbon solvents are preferred from the viewpoint of being able to dissolve octadecyltrichlorosilane, and decane is particularly preferred.

The content of the SAM-forming material is preferably in the range of 0.005% by mass to 100% by mass, more preferably in the range of 0.05% by mass to 50% by mass, and particularly preferably in the range of 1% by mass to 10% by mass, relative to the total mass of the first treatment liquid.

The first treatment liquid may also contain known additives to the extent that they do not impair the effects of the present invention. There are no particular limitations on the additives, and examples of such additives include stabilizers and surfactants.

The conditions for contacting the first processing liquid with the substrate W are not particularly limited. However, the first contact step S101 of this embodiment can shorten the contact time of the first processing liquid compared to when a SAM is formed by a conventional method. Specifically, the time required for the first contact step S101 (when the substrate W is immersed in the first processing liquid, the immersion time) can be appropriately set within the range of 1 minute to 1440 minutes, preferably 1 minute to 60 minutes, and more preferably 1 minute to 10 minutes, depending on the type of SAM-forming material, its concentration, type of solvent, etc.

Next, the SAM formation process will be explained in more detail using an example in which the SAM formation material is octadecyltrichlorosilane.

4A, when the first processing liquid is supplied to the surface of the substrate W, molecules capable of forming a SAM (octadecyltrichlorosilane, hereinafter referred to as "SAM molecules") 5 are dispersed or dissolved in the first processing liquid at the beginning of the supply. FIG. 4A is a schematic diagram showing a state in which the first processing liquid is supplied to the surface of the _SiO2 layer.

Next, as shown in FIG. 4(b), when a hydroxyl group (OH group) 6 is present on the surface of the SiO ₂ layer 1, the SAM molecule 5 is chemically adsorbed to the surface of the SiO ₂ layer 1 using the hydroxyl group 6 as a reaction site. More specifically, the trichlorosilyl group of the SAM molecule 5 reacts with the hydroxyl group 6 to form a siloxane bond, and the SAM molecule 5 is chemically adsorbed to the surface of the SiO ₂ layer 1. In addition, when water molecules 7 are present on the surface of the SiO ₂ layer 1 or in the first treatment liquid, the SAM molecule 5 aggregates around the water molecules 7. In particular, the SAM molecule 5 forms a reverse micelle 8 that encapsulates the water molecules 7 present in the first treatment liquid. Note that FIG. 4(b) is a schematic diagram showing the state in which the SAM molecule 5 is chemically adsorbed to the surface of the SiO ₂ layer 1.

Next, when the SAM molecules 5 are chemically adsorbed at a high density on the surface of the SiO ₂ layer 1, an island-like structure of the SAM molecules 5 appears on the surface. Furthermore, in each island, the SAM molecules 5 self-organize and grow (expand) due to hydrophobic and electrostatic interactions between them, and finally form a SAM ₉ (see FIG. 4(c)). However, film defects C occur in the SAM 9 in areas where reverse micelles 8 are attached to the surface of the SiO ₂ layer 1, at the boundaries between adjacent islands where the SAM molecules 5 cannot enter, and in areas where the SAM molecules 5 are attached to the surface of the SiO 2 layer 1 without being chemically adsorbed. FIG. 4(c) is a schematic diagram showing how the SAM molecules 5 self-organize on the surface of the SiO ₂ layer 1 to form a SAM 9.

2. Removal Step The removal step S102 is a step of removing the first processing solution remaining on the surface of the SiO ₂ layer 1 after the first contact step S101. As a result, excess SAM molecules 5 that do not contribute to the formation of SAM 9, more specifically, SAM molecules 5 (including reverse micelles 8) that are not chemically adsorbed on the surface of the SiO ₂ layer 1, are removed from the surface of the SiO ₂ layer 1.

The method for removing the first processing liquid from the surface of the _SiO2 layer 1 is not particularly limited, and examples thereof include a method of applying the removing liquid to the surface of the substrate W, a method of spraying the removing liquid onto the surface of the substrate W, and a method of immersing the substrate W in the removing liquid.

One method for applying the removal liquid to the surface of the substrate W is, for example, to supply the removal liquid to the center of the surface of the substrate W while the substrate W is rotated at a constant speed around its center as an axis. As a result, the removal liquid supplied to the surface of the substrate W flows from near the center of the surface of the substrate W toward the periphery of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the first processing liquid on the surface of the substrate W is replaced with the removal liquid, and the entire surface of the substrate W is covered with the removal liquid, forming a liquid film of the removal liquid.

When the SAM-forming material is octadecyltrichlorosilane, the surface of the SiO ₂ layer 1 after the removal step S102 is as shown in Fig. 5(a). As shown in the figure, SAM molecules 5 and reverse micelles 8 that do not contribute to the formation of the SAM 9 are removed from the surface of the SiO ₂ layer 1 of the substrate W. Fig. 5(a) is a schematic diagram showing the state of the surface of the SiO ₂ layer 1 after the excess SAM molecules 5 and reverse micelles 8 have been removed.

The removal liquid is preferably an organic solvent that dissolves the SAM-forming material, has low water solubility, and has a reduced water content. If the removal liquid is capable of dissolving the SAM-forming material, the excess SAM molecules 5 and reverse micelles 8 that do not contribute to the formation of the SAM 9 can be effectively removed from the surface of the SiO ₂ layer 1. The removal liquid is preferably one having a water solubility of about 0.033% (330 ppm) or less at 25° C., for example. More specifically, examples of the removal liquid include toluene, decane, and 1,3-bis(trifluoromethyl)benzene. These solvents can be used alone or in combination of two or more.

3. Surface Modification Step The surface modification step S103 is a step of modifying the surface of the SiO ₂ layer 1 in an area where a film defect C occurs, i.e., an area where a SAM 9 is not formed, into an area capable of chemical adsorption by the SAM molecule 5. Here, in this specification, "modifying the surface into an area capable of chemical adsorption" means, for example, performing surface modification so that hydroxyl groups (OH groups) are generated on the surface of the SiO ₂ layer 1. Alternatively, the surface modification in this embodiment can be said to be a process of generating silanol groups (Si-OH groups) on the SiO ₂ layer 1.

When the surface of the _SiO2 layer 1 is modified, as shown in Fig. 5(b), hydroxyl groups 6 are generated in the film defects C of the SAM 9 so as to enable chemical adsorption of the SAM molecules 5. Fig. 5(b) is a schematic diagram showing how the surface is modified in an area where no SAM molecules 5 are present, and hydroxyl groups 6 are generated.

In this embodiment, the surface of the _SiO2 layer 1 is modified by a wet method. More specifically, the surface is modified by bringing a surface modification liquid into contact with the surface of the substrate W after the removal step S102. The method of bringing the surface modification liquid into contact with the surface of the substrate W is not particularly limited, and examples thereof include a method of applying the surface modification liquid to the surface of the substrate W, a method of spraying the surface modification liquid onto the surface of the substrate W, and a method of immersing the substrate W in the surface modification liquid.

Another method of applying the surface modification liquid to the surface of the substrate W is, for example, to supply the surface modification liquid to the center of the surface of the substrate W while the substrate W is rotated at a constant speed around its center as an axis. As a result, the surface modification liquid supplied to the surface of the substrate W flows from near the center of the surface of the substrate W toward the peripheral edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the entire surface of the substrate W is covered with the surface modification liquid, and a liquid film of the surface modification liquid is formed.

Examples of surface modification liquids include SC-1 (Standard Clean-1) (volume ratio of ammonium water ( _NH3 concentration 28%): _hydrogen peroxide water ( _H2O2 concentration 30%): DIW = 1:4:20), ammonium hydroxide ( _NH4OH ), hydrogen peroxide water ( _H2O2 ), ammonium fluoride ( _NH4F ), dilute sulfuric acid/hydrogen peroxide water ( _SPM ), dilute nitric acid, a mixed solution of hydrofluoric acid and ammonia, ozone water, ozonized deionized water, water, etc. Among these surface modification liquids, SC-1 is preferred from the viewpoint of being able to effectively introduce hydroxyl groups into the surface of the _SiO2 layer 1.

When the surface modification step S103 is performed by a wet method, it is preferable to sequentially perform a cleaning step for removing the surface modification liquid and a drying step immediately after the surface modification step S103. The cleaning method in the cleaning step is not particularly limited, and examples thereof include a method of supplying a cleaning liquid to the surface of the substrate W and a method of immersing the substrate W in the cleaning liquid. Examples of the cleaning liquid include toluene, decane, and 1,3-bis(trifluoromethyl)benzene. These solvents can be used alone or in a mixture of two or more. The cleaning conditions such as the cleaning time and the temperature of the cleaning liquid are not particularly limited, and can be set appropriately as needed. The drying step is intended to remove the cleaning liquid remaining on the surface of the substrate W. The drying method is not particularly limited, and examples thereof include a method of spraying an inert gas such as nitrogen gas onto the surface of the substrate W. The drying conditions such as the drying time and the drying temperature are not particularly limited, and can be set appropriately as needed.

4. Densification Treatment Step The densification treatment step (second contact step) S104 is a step of contacting the surface of the SiO ₂ layer 1 after the surface modification step S103 with a second treatment liquid containing a SAM-forming material. In the area where the film defect C occurs, hydroxyl groups 6 are generated on the surface of the SiO ₂ layer 1 by the surface modification step S103. Therefore, as shown in FIG. 5(c), by contacting the surface of the SiO ₂ layer 1 with the second treatment liquid, the SAM molecule 5 can be chemically adsorbed to the area where the film defect C occurs by siloxane bonding with the hydroxyl group 6. As a result, the film defect C is repaired, and a densified SAM 9' is formed. Note that FIG. 5(c) is a schematic diagram showing how the SAM 9 is densified.

The method for contacting the second processing liquid with the substrate W is the same as the contact method for the first processing liquid in the first contact step S101 described above. Therefore, a detailed description thereof will be omitted.

The second treatment liquid contains at least a SAM-forming material and a solvent, similar to the first treatment liquid in the first contact step S101. The second treatment liquid may be the same type as the first treatment liquid or may be a different type. When a second treatment liquid different from the first treatment liquid is used, the content of the SAM-forming material and the type of solvent are not particularly limited. However, it is preferable that the SAM-forming material is the same as the SAM-forming material of the first treatment liquid.

There are no particular limitations on the conditions for contacting the second processing liquid with the substrate W. For example, the contact time of the second processing liquid (the immersion time, when the substrate W is immersed in the second processing liquid) can be appropriately set within the range of 1 minute to 1440 minutes, preferably 1 minute to 60 minutes, and more preferably 1 minute to 5 minutes, depending on the type of SAM-forming material, its concentration, the type of solvent, the frequency of occurrence of film defects C within the surface of the SAM 9, the area of the occurrence region, etc.

5. Rinse Step The rinse step S105 is a step of removing the second processing liquid from the surface of the _SiO2 layer 1. Specifically, the rinse step S105 is performed by supplying a rinse liquid to the surface of the substrate W and replacing the remaining second processing liquid with the rinse liquid.

The method of contacting the surface of the substrate W with the rinse liquid is not particularly limited, and examples thereof include a method of directly supplying and applying the rinse liquid onto the substrate W, a method of spraying the rinse liquid, and a method of immersing the substrate W in the rinse liquid. An example of a method of applying the rinse liquid to the surface of the substrate W is a method of supplying the rinse liquid to the center of the surface of the substrate W while rotating the substrate W at a constant speed around its center. As a result, the rinse liquid supplied to the surface of the substrate W flows from the center of the surface of the substrate W toward the peripheral portion of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the entire surface of the substrate W is covered with the rinse liquid, forming a liquid film of the rinse liquid, and the processing liquid can be replaced with the rinse liquid. The time of the rinsing process is not particularly limited, and can be set appropriately as needed.

Examples of the rinse solution include toluene, decane, and 1,3-bis(trifluoromethyl)benzene. These solvents can be used alone or in combination of two or more. Rinsing conditions such as the rinse time and the temperature of the rinse solution are not particularly limited and can be set appropriately as needed.

It is preferable to perform a drying process immediately after the rinsing process S105 in order to remove the rinsing liquid remaining on the surface of the substrate W. The drying method is not particularly limited, and examples include a method of spraying an inert gas such as nitrogen gas onto the surface of the substrate W. The drying conditions, such as the drying time and drying temperature, are not particularly limited, and can be set appropriately as needed.

As a result, in the SAM formation step S1, as shown in FIG. 2(b), a SAM 9' having excellent density and protective performance can be formed on the surface of the SiO ₂ layer 1. In the SAM formation step S1, in order to form a dense SAM 9', a surface modification is performed on the area (film defect C) on the surface of the SiO ₂ layer 1 where the SAM molecules cannot be chemically adsorbed. Furthermore, the film defect C is repaired by chemically adsorbing the SAM molecules 5 on the surface-modified area. As a result, a SAM 9' having high film density, excellent density, suppressed or reduced occurrence of film defects, and excellent function as a protective film can be formed in a shorter time than the conventional method. Note that FIG. 2(b) is a partial enlarged view showing a state in which the SAM 9' is formed on the surface of the SiO ₂ layer 1.

<Etching process S2>
The etching step S2 is a step of selectively etching the SiN layer 2, which is a sacrificial layer and a layer to be etched. More specifically, this is a step of bringing an etching solution into contact with the SiN layer 2 through the memory trench 4 to remove the SiN layer 2. In this step, the SAM 9 functions as a protective layer to protect the SiO ₂ layer 1. This makes it possible to effectively suppress the SiO ₂ layer 1 from being etched.

One method for applying the etching liquid to the surface of the substrate W is, for example, to supply the etching liquid to the center of the surface of the substrate W while the substrate W is rotated at a constant speed around its center as an axis. As a result, the etching liquid supplied to the surface of the substrate W flows from near the center of the surface of the substrate W toward the peripheral edge of the substrate W due to the centrifugal force generated by the rotation of the substrate W, and is spread over the entire surface of the substrate W. As a result, the entire surface of the substrate W is covered with the etching liquid, and a liquid film of the etching liquid is formed.

The etching liquid can be appropriately set in consideration of the constituent material of the layer to be etched, the etching rate, etc. When the layer to be etched is the SiN layer 2 as in this embodiment, for example, an aqueous solution of phosphoric acid (H ₃ PO ₄ ) or hydrofluoric acid (for example, HF:DIW=1:100 in volume ratio) can be used as the etching liquid. The concentration of the etching liquid can also be appropriately set in consideration of the constituent material of the layer to be etched, the etching rate, etc.

The etching temperature (i.e., the temperature of the etching solution) and the etch rate for the layer to be etched can be set appropriately taking into account the constituent material of the layer to be etched.

It is preferable to sequentially perform a rinsing step for removing the etching liquid and a drying step immediately after the etching step S2. The rinsing method in the rinsing step is not particularly limited, and examples thereof include a method of supplying a rinsing liquid to the surface of the substrate W and a method of immersing the substrate W in the rinsing liquid. The rinsing liquid is not particularly limited, and examples thereof include DIW. The cleaning conditions such as the rinsing time and the temperature of the rinsing liquid are not particularly limited, and can be set appropriately as needed. The drying step is intended to remove the rinsing liquid remaining on the surface of the substrate W. The drying method is not particularly limited, and examples thereof include a method of spraying an inert gas such as nitrogen gas onto the surface of the substrate W. The drying conditions such as the drying time and the drying temperature are not particularly limited, and can be set appropriately as needed.

As a result, in the etching step S2, only the SiN layer 2 can be selectively removed as shown in Fig. 2(c). In addition, the SAM 9, which has excellent density and protective performance, covers and protects the surface of the _SiO2 layer 1, so that the _SiO2 layer 1 can be prevented from being etched and the etched silicon component can be prevented from precipitating and adhering to the surface of the _SiO2 layer 1. Furthermore, the allowable range of the concentration of silicon contained in the etching solution such as phosphoric acid can be increased. Note that Fig. 2(c) is a partial enlarged view of the portion surrounded by B in the laminate in Fig. 1(b), showing the state in which the SiN layer 2 has been etched.

[Semiconductor manufacturing equipment]
Next, the semiconductor manufacturing apparatus according to this embodiment will be described below with reference to the drawings.
The semiconductor manufacturing apparatus of the present embodiment includes at least a substrate processing unit for forming a SAM and an etching processing unit for etching a layer to be etched, and may also include a control unit for controlling each unit of the semiconductor manufacturing apparatus.

<Substrate Processing Unit>
The substrate processing unit 100 of this embodiment is a single-wafer processing unit used to form a SAM, and includes at least a substrate holding section 110 for holding a substrate W, a supply section 120 for supplying a first processing liquid and a second processing liquid to the front surface Wf of the substrate W, a removing liquid supply section 130 for supplying a removing liquid, a surface modifying liquid supply section (surface modifying section) 140, a chamber 150 which is a container for accommodating the substrate W, a splash prevention cup 160 for collecting the processing liquid, and a swivel drive section 170 for independently swivel-driving the arms of each section of the substrate processing unit 100, which will be described later. The substrate processing unit 100 may also include a loading/unloading means (not shown) for loading or unloading the substrate W. FIG. 6 is an explanatory diagram showing a schematic configuration of the substrate processing unit 100 according to this embodiment. In the figure, XYZ orthogonal coordinate axes are appropriately displayed in order to clarify the directional relationship of the illustrated items. Here, the XY plane represents a horizontal plane, and the +Z direction represents a vertical upward direction.

1. Substrate Holding Unit The substrate holding unit 110 is a means for holding the substrate W, and as shown in FIG. 6, holds and rotates the substrate W in a substantially horizontal position with the surface Wf of the substrate W facing upward. The substrate holding unit 110 has a spin chuck 113 in which a spin base 111 and a rotation support shaft 112 are integrally connected. The spin base 111 has a substantially circular shape in a plan view, and a hollow rotation support shaft 112 extending substantially vertically is fixed to the center of the spin base 111. The rotation support shaft 112 is connected to a rotation shaft of a chuck rotation mechanism 114 including a motor. The chuck rotation mechanism 114 is housed in a cylindrical casing 115, and the rotation support shaft 112 is supported by the casing 115 so as to be rotatable around a vertical rotation shaft.

The chuck rotation mechanism 114 can rotate the rotating support shaft 112 around the rotation axis by being driven by a chuck drive unit (not shown) of the control unit 300. This causes the spin base 111 attached to the upper end of the rotating support shaft 112 to rotate around the rotation axis J1. The control unit 300 can control the chuck rotation mechanism 114 via the chuck drive unit to adjust the rotation speed of the spin base 111.

A number of chuck pins 116 for gripping the peripheral edge of the substrate W are erected near the peripheral edge of the spin base 111. The number of chuck pins 116 to be installed is not particularly limited, but it is preferable to provide at least three or more in order to securely hold the circular substrate W. In this embodiment, three chuck pins 116 are arranged at equal intervals along the peripheral edge of the spin base 111. Each chuck pin 116 includes a substrate support pin that supports the peripheral edge of the substrate W from below, and a substrate holding pin that holds the substrate W by pressing against the outer peripheral end face of the substrate W supported by the substrate support pin.

2. Supply Unit The supply unit 120 according to the present embodiment is a unit for supplying the first processing liquid and the second processing liquid to the front surface Wf of the substrate W. As shown in FIG. 6 , the supply unit 120 includes a processing liquid storage unit 121, a nozzle 122, and an arm 123.

When the same type of processing liquid is used as the first processing liquid and the second processing liquid, the processing liquid storage section 121 includes a pressurizing section 124 and a processing liquid tank 125 as shown in FIG. 7. FIG. 7 is an explanatory diagram showing the schematic configuration of the processing liquid storage section 121 in the supply section 120 of the substrate processing unit 100.

The pressurizing unit 124 includes a nitrogen gas supply source 124a, which is a gas supply source for pressurizing the inside of the processing liquid tank 125, a pump (not shown) for pressurizing the nitrogen gas, a nitrogen gas supply pipe 124b, and a valve 124c provided midway along the nitrogen gas supply pipe 124b.

The nitrogen gas supply pipe 124b is connected to the processing liquid tank 125. Furthermore, a valve 124c is provided in the middle of the nitrogen gas supply pipe 124b. The valve 124c is electrically connected to the control unit 300, and the opening and closing of the valve 124c can be controlled by an operation command from the control unit 300. When the valve 124c is opened by an operation command from the control unit 300, nitrogen gas can be supplied to the processing liquid tank 125.

The processing liquid tank 125 may include an agitation unit that agitates the processing liquid in the processing liquid tank 125, and a temperature adjustment unit that adjusts the temperature of the processing liquid (neither is shown). Examples of the agitation unit include a rotating unit that agitates the processing liquid, and an agitation control unit that controls the rotation of the rotating unit. The agitation control unit is electrically connected to the control unit 300, and the rotating unit has, for example, a propeller-shaped agitation blade at the lower end of the rotating shaft. The control unit 300 issues an operation command to the agitation control unit to rotate the rotating unit, thereby causing the agitation blade to agitate the processing liquid. As a result, the concentration and temperature of the processing liquid can be made uniform in the processing liquid tank 125.

Furthermore, a discharge pipe 125a for supplying the processing liquid to the nozzle 122 is connected to the processing liquid tank 125. A discharge valve 125b is provided midway along the discharge pipe 125a. The discharge valve 125b is also electrically connected to the control unit 300. This allows the opening and closing of these valves to be controlled by operational commands from the control unit 300. When the discharge valve 125b is opened by an operational command from the control unit 300, the processing liquid is pressure-fed to the nozzle 122 via the discharge pipe 125a.

The nozzle 122 is attached to the tip of a horizontally extending arm 123, and is positioned above the spin base 111 when discharging the treatment liquid. The arm 123 is connected to a rotation drive unit 170 via a rotation shaft (not shown). The rotation drive unit 170 is electrically connected to the control unit 300, and rotates the arm 123 according to an operation command from the control unit 300. As the arm 123 rotates, the nozzle 122 also moves.

When the supply unit 120 supplies first and second processing liquids of different types, a processing liquid storage unit 121' equipped with a pair of a first processing liquid tank 126 and a second processing liquid tank 127 may be used as shown in FIG. 8. This allows different types of processing liquid to be used in the first contact step S101 and the densification step S104. FIG. 8 is an explanatory diagram showing the schematic configuration of the processing liquid storage unit 121' in the supply unit 120 of the substrate processing unit 100.

More specifically, the treatment liquid storage section 121' has the following configuration. That is, the first treatment liquid tank 126 stores the first treatment liquid, and the second treatment liquid tank 127 stores the second treatment liquid. In addition, the nitrogen gas supply pipe 124b branches into a first nitrogen gas supply pipe 124d and a second nitrogen gas supply pipe 124e. The first nitrogen gas supply pipe 124d is connected to the first treatment liquid tank 126, and the second nitrogen gas supply pipe 124e is connected to the second treatment liquid tank 127. Furthermore, a first valve 124f is provided on the middle path of the first nitrogen gas supply pipe 124d, and a second valve 124g is provided on the middle path of the second nitrogen gas supply pipe 124e. The valves 124c, the first valve 124f, and the second valve 124g are each electrically connected to the control unit 300, and the opening and closing of the valves 124c, the first valve 124f, and the second valve 124g can be controlled by an operation command from the control unit 300. When the valves 124c, the first valve 124f, and the second valve 124g are opened by an operation command from the control unit 300, nitrogen gas can be supplied to each of the first processing liquid tank 126 and the second processing liquid tank 127.

The first processing liquid tank 126 and the second processing liquid tank 127 may each be provided with an agitation unit that agitates the first processing liquid in the first processing liquid tank 126 and the second processing liquid in the second processing liquid tank 127, and a temperature adjustment unit that adjusts the temperature of the first processing liquid and the second processing liquid (neither is shown). Examples of the agitation unit include a rotating unit that agitates the first processing liquid or the second processing liquid, and an agitation control unit that controls the rotation of the rotating unit. The agitation control unit is electrically connected to the control unit 300, and the rotating unit is provided with, for example, a propeller-shaped agitation blade at the lower end of the rotating shaft. The control unit 300 rotates the rotating unit by issuing an operation command to the agitation control unit, thereby allowing the agitation blade to agitate the first processing liquid or the second processing liquid. As a result, the concentration and temperature of the first processing liquid and the second processing liquid can be made uniform in the first processing liquid tank 126, etc.

Furthermore, the first treatment liquid tank 126 and the second treatment liquid tank 127 are respectively connected to a first discharge pipe 126a and a second discharge pipe 127a for supplying the first treatment liquid or the second treatment liquid to the nozzle 122. A first discharge valve 126b is provided on the middle path of the first discharge pipe 126a. A second discharge valve 127b is provided on the middle path of the second discharge pipe 127a. Furthermore, the first discharge pipe 126a and the second discharge pipe 127a are connected to a third discharge pipe 128 so as to merge downstream of the first discharge valve 126b and the second discharge valve 127b. A third discharge valve 128a is provided on the middle path of this third discharge pipe 128. In addition, the first discharge valve 126b, the second discharge valve 127b, and the third discharge valve 128a are electrically connected to the control unit 300. As a result, the opening and closing of these valves can be controlled by the operation command of the control unit 300. When the first exhaust valve 126b and the third exhaust valve 128a are opened by an operation command from the control unit 300, the first treatment liquid is pressure-fed to the nozzle 122 via the first exhaust pipe 126a and the third exhaust pipe 128. When the second exhaust valve 127b and the third exhaust valve 128a are opened by an operation command from the control unit 300, the second treatment liquid is pressure-fed to the nozzle 122 via the second exhaust pipe 127a and the third exhaust pipe 128.

The removing liquid supply unit 130 according to the present embodiment is a unit for supplying the removing liquid to the front surface Wf of the substrate W. As shown in FIG. 6 , the removing liquid supply unit 130 includes a removing liquid storage unit 131, a nozzle 132, and an arm 133.

As shown in FIG. 9, the removal liquid storage section 131 has a function of supplying the removal liquid to the nozzle 132, and includes a pressurizing section 134 and a removal liquid tank 135. FIG. 9 is an explanatory diagram showing the schematic configuration of the removal liquid storage section 131 in the removal liquid supply section 130 of the substrate processing unit 100.

The pressurizing unit 134 includes a nitrogen gas supply source 134a, which is a gas supply source for pressurizing the inside of the removal liquid tank 135, a pump (not shown) for pressurizing the nitrogen gas, a nitrogen gas supply pipe 134b, and a valve 134c provided midway along the nitrogen gas supply pipe 134b.

The nitrogen gas supply pipe 134b is connected to the removal liquid tank 135. Furthermore, a valve 134c is provided in the middle of the nitrogen gas supply pipe 134b. The valve 134c is electrically connected to the control unit 300, and the opening and closing of the valve 134c can be controlled by an operation command from the control unit 300. When the valve 134c is opened by an operation command from the control unit 300, nitrogen gas can be supplied to the removal liquid tank 135.

The removal liquid tank 135 may include an agitation unit that agitates the removal liquid in the removal liquid tank 135, and a temperature adjustment unit that adjusts the temperature of the removal liquid (neither is shown). Examples of the agitation unit include a rotation unit that agitates the removal liquid in the removal liquid tank 135, and an agitation control unit that controls the rotation of the rotation unit. The agitation control unit is electrically connected to the control unit 300, and the rotation unit is equipped with, for example, a propeller-shaped agitation blade at the lower end of the rotation shaft. The control unit 300 issues an operation command to the agitation control unit to rotate the rotation unit, thereby agitating the removal liquid with the agitation blade. As a result, the concentration and temperature of the removal liquid can be made uniform in the removal liquid tank 135.

The removal liquid tank 135 is further connected to a discharge pipe 135a for supplying the removal liquid to the nozzle 132. A discharge valve 135b is provided midway along the discharge pipe 135a. The discharge valve 135b is electrically connected to the control unit 300. This allows the opening and closing of the discharge valve 135b to be controlled by an operational command from the control unit 300. When the discharge valve 135b is opened by an operational command from the control unit 300, the removal liquid is pressure-fed to the nozzle 132 via the discharge pipe 135a.

The nozzle 132 is attached to the tip of a horizontally extending arm 133, and is positioned above the spin base 111 when ejecting the removal liquid. The arm 133 is connected to a rotation drive unit 170 via a rotation shaft (not shown). The rotation drive unit 170 is electrically connected to the control unit 300, and rotates the arm 133 according to an operation command from the control unit 300. As the arm 133 rotates, the nozzle 132 also moves.

4. Surface Modification Liquid Supply Unit The surface modification liquid supply unit 140 according to this embodiment is a unit that supplies a surface modification liquid to the front surface Wf of the substrate W. As shown in FIG. 6 , the surface modification liquid supply unit 140 has a surface modification liquid storage unit 141, a nozzle 142, and an arm 143.

As shown in FIG. 10, the surface modification liquid storage section 141 has a function of supplying the surface modification liquid to the nozzle 142, and includes a pressurizing section 144 and a surface modification liquid tank 145. FIG. 10 is an explanatory diagram showing the schematic configuration of the surface modification liquid storage section 141 in the surface modification liquid supply section 140 of the substrate processing unit 100.

The pressurizing unit 144 includes a nitrogen gas supply source 144a, which is a gas supply source for pressurizing the surface modification liquid tank 145, a pump (not shown) for pressurizing the nitrogen gas, a nitrogen gas supply pipe 144b, and a valve 144c provided midway along the nitrogen gas supply pipe 144b.

The nitrogen gas supply pipe 144b is connected to the surface modification liquid tank 145. Furthermore, a valve 144c is provided in the middle of the nitrogen gas supply pipe 144b. The valve 144c is electrically connected to the control unit 300, and the opening and closing of the valve 144c can be controlled by an operation command from the control unit 300. When the valve 144c is opened by an operation command from the control unit 300, nitrogen gas can be supplied to the surface modification liquid tank 145.

The surface modification liquid tank 145 may include an agitation unit that agitates the surface modification liquid in the surface modification liquid tank 145, and a temperature adjustment unit that adjusts the temperature of the surface modification liquid (neither is shown). Examples of the agitation unit include a rotation unit that agitates the surface modification liquid in the surface modification liquid tank 145, and an agitation control unit that controls the rotation of the rotation unit. The agitation control unit is electrically connected to the control unit 300, and the rotation unit is provided with, for example, a propeller-shaped agitation blade at the lower end of the rotation shaft. The control unit 300 issues an operation command to the agitation control unit to rotate the rotation unit, thereby allowing the agitation blade to agitate the surface modification liquid. As a result, the concentration and temperature of the surface modification liquid can be made uniform in the surface modification liquid tank 145.

Furthermore, a discharge pipe 145a for supplying the surface modification liquid to the nozzle 142 is connected to the surface modification liquid tank 145. A discharge valve 145b is provided midway along the discharge pipe 145a. This discharge valve 145b is electrically connected to the control unit 300. This allows the opening and closing of the discharge valve 145b to be controlled by an operational command from the control unit 300. When the discharge valve 145b is opened by an operational command from the control unit 300, the surface modification liquid is pressure-fed to the nozzle 142 via the discharge pipe 145a.

The nozzle 142 is attached to the tip of a horizontally extending arm 143, and is positioned above the spin base 111 when discharging the surface modification liquid. The arm 143 is connected to a rotation drive unit 170 via a rotation shaft (not shown). The rotation drive unit 170 is electrically connected to the control unit 300, and rotates the arm 143 according to an operation command from the control unit 300. As the arm 143 rotates, the nozzle 142 also moves.

5. Splash prevention cup The splash prevention cup 160 is provided to surround the spin base 111. The splash prevention cup 160 is connected to a lift drive mechanism (not shown) and can be raised and lowered in the vertical direction. When the first processing liquid, etc. is supplied to the front surface Wf of the substrate W, the splash prevention cup 160 is positioned at a predetermined position by the lift drive mechanism and surrounds the substrate W held by the chuck pins 116 from a lateral position. This makes it possible to collect the first processing liquid, etc. splashed from the substrate W and the spin base 111.

<Etching Processing Unit>
The etching processing unit 200 of this embodiment is a single-wafer processing unit used to etch a layer to be etched, and as shown in FIG. 11, includes at least a substrate holding part 210 for holding a substrate W, an etching liquid supply part 220 for supplying an etching liquid to the front surface Wf of the substrate W, a chamber 250 which is a container for accommodating the substrate W, a splash prevention cup 260 for collecting the etching liquid, and a swivel drive part 270 for independently swivel-driving the arms of the etching liquid supply part 220 described later. The etching processing unit 200 may also include a loading/unloading means (not shown) for loading/unloading the substrate W. FIG. 11 is an explanatory diagram showing a schematic configuration of the etching processing unit 200 according to this embodiment. In this figure, XYZ orthogonal coordinate axes are appropriately displayed to clarify the directional relationship of the objects shown in the figure. Here, the XY plane represents the horizontal plane, and the +Z direction represents the vertical upward direction.

1. Substrate Holding Unit The substrate holding unit 210 is a means for holding the substrate W, and as shown in FIG. 11, holds and rotates the substrate W in a substantially horizontal position with the surface Wf of the substrate W facing upward. The substrate holding unit 210 has a spin chuck 213 in which a spin base 211 and a rotation support shaft 212 are integrally connected. The spin base 211 has a substantially circular shape in a plan view, and a hollow rotation support shaft 212 extending substantially vertically is fixed to the center of the spin base 211. The rotation support shaft 212 is connected to a rotation shaft of a chuck rotation mechanism 214 including a motor. The chuck rotation mechanism 214 is housed in a cylindrical casing 215, and the rotation support shaft 212 is supported by the casing 215 so as to be rotatable around a vertical rotation shaft.

The chuck rotation mechanism 214 can rotate the rotating support shaft 212 around the rotation axis by being driven by a chuck drive unit (not shown) of the control unit 300. This causes the spin base 211 attached to the upper end of the rotating support shaft 212 to rotate around the rotation axis J2. The control unit 300 can control the chuck rotation mechanism 214 via the chuck drive unit to adjust the rotation speed of the spin base 211.

A number of chuck pins 216 for gripping the peripheral edge of the substrate W are erected near the peripheral edge of the spin base 211. The number of chuck pins 216 to be installed is not particularly limited, but it is preferable to provide at least three or more in order to securely hold the circular substrate W. In this embodiment, three chuck pins 216 are arranged at equal intervals along the peripheral edge of the spin base 211. Each chuck pin 216 includes a substrate support pin that supports the peripheral edge of the substrate W from below, and a substrate holding pin that holds the substrate W by pressing against the outer peripheral end face of the substrate W supported by the substrate support pin.

2. Etching Liquid Supply Unit The etching liquid supply unit 220 according to this embodiment is a unit for supplying an etching liquid to the front surface Wf of the substrate W. As shown in FIG. 11 , the etching liquid supply unit 220 has an etching liquid storage unit 221, a nozzle 222, and an arm 223.

As shown in FIG. 12, the etching liquid storage section 221 includes at least an etching liquid tank 224, a temperature regulator 225, a liquid delivery pump 226, and a particle filter 227. FIG. 12 is an explanatory diagram showing the schematic configuration of the etching liquid storage section 221 in the etching liquid supply section 220.

The etching solution tank 224 may include an agitation unit (not shown) that agitates the etching solution in the etching solution tank 224. Examples of the agitation unit include a rotating unit that agitates the etching solution and an agitation control unit that controls the rotation of the rotating unit. The agitation control unit is electrically connected to the control unit 300, and the rotating unit is equipped with a propeller-shaped agitation blade at the lower end of the rotating shaft, for example. The control unit 300 issues an operation command to the agitation control unit to rotate the rotating unit, thereby allowing the etching solution to be agitated by the agitation blade. As a result, the concentration and temperature of the etching solution can be made uniform in the etching solution tank 224.

The etching solution tank 224 is provided with a mixer 228 that can mix chemicals and DIW from an external supply source (not shown) to prepare an etching solution of a predetermined concentration. The chemicals are solutes that function as etchants. Examples of chemicals include the aforementioned phosphoric acid and hydrogen fluoride.

The etching solution tank 224 is also connected to a discharge pipe 229 for supplying the etching solution to the nozzle 222. A temperature regulator 225, a liquid delivery pump 226, and a particle filter 227 are sequentially inserted in the middle of the discharge pipe 229 from upstream to downstream. The temperature regulator 225 and the liquid delivery pump 226 are electrically connected to the control unit 300. This allows the temperature of the etching solution supplied to the nozzle 222 to be controlled by an operation command from the control unit 300. When the liquid delivery pump 226 is controlled by an operation command from the control unit 300, the etching solution can be pressure-fed to the nozzle 222 through the discharge pipe 229. The particle filter 227 can remove foreign matter such as particles in the etching solution.

The nozzle 222 is attached to the tip of a horizontally extending arm 223, and is positioned above the spin base 211 when ejecting the etching solution. The arm 223 is connected to a rotation drive unit 270 via a rotation shaft (not shown). The rotation drive unit 270 is electrically connected to the control unit 300, and rotates the arm 223 according to an operation command from the control unit 300. As the arm 223 rotates, the nozzle 222 also moves.

3. Splash prevention cup The splash prevention cup 260 is provided to surround the spin base 211. The splash prevention cup 260 is connected to a lift drive mechanism (not shown) and can be raised and lowered in the vertical direction. When supplying the etching liquid to the front surface Wf of the substrate W, the splash prevention cup 260 is positioned at a predetermined position by the lift drive mechanism and surrounds the substrate W held by the chuck pins 216 from a lateral position. This makes it possible to collect the etching liquid splashed from the substrate W and the spin base 211.

<Control Unit>
The control unit 300 is electrically connected to each part of the semiconductor manufacturing apparatus, i.e., the substrate processing unit 100 and the etching processing unit 200, and controls the operation of each part. The control unit 300 is composed of a computer having an arithmetic unit and a storage unit. The arithmetic unit uses a CPU that performs various arithmetic processing. The storage unit includes a ROM, which is a read-only memory that stores a substrate processing program and an etching processing program, a RAM, which is a readable and writable memory that stores various information, and a magnetic disk that stores control software, data, and the like. The magnetic disk stores processing conditions in advance, including supply conditions for the first processing liquid, the second processing liquid, the removal liquid, the surface modification liquid, and the etching liquid, rinse conditions, SAM film formation conditions, and etching conditions. The CPU reads the processing conditions into the RAM and controls each part of the semiconductor manufacturing apparatus according to the contents.

Second Embodiment
A method and apparatus for manufacturing a semiconductor device according to the second embodiment of the present invention will now be described.
The present embodiment differs from the first embodiment mainly in that the SiN layer 2 is etched to a predetermined depth in its thickness direction immediately before forming the SAM on the surface of the SiO ₂ layer 1. With such a configuration, it is possible to selectively etch only the SiN layer 2. In addition, since the SAM 9', which has excellent density and protective performance, covers and protects the surface and side of the SiO ₂ layer 1, it is possible to prevent the SiO ₂ layer 1 from being etched and the etched silicon component from precipitating and adhering to the surface of the SiO ₂ layer 1. Furthermore, it is possible to increase the allowable range of the concentration of silicon contained in an etching solution such as phosphoric acid.

[Method of Manufacturing Semiconductor Device]
The method for manufacturing a semiconductor device according to this embodiment will be described below with reference to Fig. 13 and Fig. 14(a) to Fig. 14(c). Fig. 13 is a flow chart showing an example of the overall flow of the method for manufacturing a semiconductor device according to the second embodiment of the present invention. Fig. 14(a) is a partially enlarged view showing the state where the SiN layer 2 is partially etched to a predetermined depth in its film thickness direction, Fig. 14(b) is a partially enlarged view showing the state where a SAM 9' is formed on the surface of the _SiO2 layer 1, and Fig. 14(c) is a partially enlarged view showing the state where the SiN layer 2 is etched.

As shown in FIG. 13, the method for manufacturing a semiconductor device according to this embodiment includes at least a first etching step S3, a SAM formation step S4, and a second etching step S5, and enables the SiN layer 2 to be selectively etched stepwise through the memory trench 4, thereby forming a recess on the side of the memory trench 4 in the stack 3.

<First Etching Step>
The first etching step S3 is a step of partially and selectively etching the SiN layer 2, which is a sacrificial layer and a layer to be etched. More specifically, the first etching solution is brought into contact with the SiN layer 2 through the memory trench 4, and the SiN layer 2 is partially removed to a predetermined depth in the thickness direction (see FIG. 14A).

The method for applying the first etching liquid to the surface of the substrate W can be the same as the method for applying the etching liquid in the etching step S2 of the first embodiment. Therefore, a detailed description thereof will be omitted.

The first etching liquid is not particularly limited, and can be appropriately set in consideration of the constituent material of the layer to be etched, the etch rate, etc. When the layer to be etched is the SiN layer 2 as in this embodiment, for example, an aqueous solution of phosphoric acid (H ₃ PO ₄ ) or hydrofluoric acid (for example, HF:DIW=1:100 in volume ratio) can be used as the first etching liquid. The concentration of the first etching liquid is also not particularly limited, and can be appropriately set in consideration of the constituent material of the layer to be etched, the etch rate, the degree of etching depth in the film thickness direction of the layer to be etched, etc.

The etching temperature (i.e., the temperature of the first etching liquid) and the etch rate for the layer to be etched are not particularly limited, and can be set appropriately depending on the material of the layer to be etched and the etching depth in the film thickness direction of the layer to be etched.

In addition, immediately after the first etching step S3, it is preferable to sequentially perform a rinsing step to remove the first etching solution and a drying step. The rinsing step and drying step are similar to the rinsing step and drying step performed immediately after the etching step S2 in the first embodiment. Therefore, a detailed description thereof will be omitted.

<SAM formation process>
As shown in Fig. 13, the SAM formation step S4 includes at least a first contact step S101, a removal step S102, a surface modification step S103, a densification treatment step S104, and a rinsing step S105. In the SAM formation step S4, as shown in Fig. 14(b), a SAM 9' is formed on the surface of the _SiO2 layer 1. The SAM 9' is also formed on the side surface of the _SiO2 layer 1 exposed by etching the SiN layer 2 to a predetermined depth in the film thickness direction in the etching step S3.

In the SAM formation step S4, in order to form a dense SAM 9', a surface modification is applied to the area (film defect) on the surface of the _SiO2 layer 1 where the SAM molecules cannot be chemically adsorbed. Furthermore, the film defect is repaired by chemically adsorbing the SAM molecules to the surface-modified area. As a result, a SAM 9' having high film density and excellent compactness, in which the occurrence of film defects is suppressed or reduced, and which has excellent functions as a protective film, can be formed in a shorter time than with the conventional method.

The first contact step S101, the removal step S102, the surface modification step S103, the densification treatment step S104, and the rinsing step S105 in the SAM formation step S4 are the same as those in the first embodiment. Therefore, a detailed description of each of these steps will be omitted.

<Second Etching Step>
The second etching step S5 is a step of selectively etching the partially remaining SiN layer 2' to completely remove it. More specifically, the second etching solution is brought into contact with the remaining SiN layer 2' through the memory trench 4 to completely remove the SiN layer 2'.

The method for applying the second etching liquid to the surface of the substrate W can be the same as the method for applying the etching liquid in the etching step S2 of the first embodiment. Therefore, a detailed description thereof will be omitted.

The second etching liquid is not particularly limited, and can be appropriately set in consideration of the constituent material of the etched layer, the etch rate, etc. The second etching liquid may be the same as or different from the first etching liquid. When the etched layer is a SiN layer 2 as in this embodiment, for example, a phosphoric acid (H ₃ PO ₄ ) aqueous solution or hydrofluoric acid (for example, HF:DIW=1:100 in volume ratio) can be used as the second etching liquid. The concentration of the second etching liquid is also not particularly limited, and can be appropriately set in consideration of the constituent material of the etched layer, the etch rate, the degree of etching depth in the thickness direction of the etched layer, etc.

In addition, the etching temperature (i.e., the temperature of the second etching liquid) and the etch rate for the layer to be etched are not particularly limited and can be set appropriately depending on the constituent material of the layer to be etched, etc.

In addition, immediately after the second etching step S5, it is preferable to sequentially perform a rinsing step to remove the second etching solution and a drying step. The rinsing step and drying step are similar to the rinsing step and drying step performed immediately after the etching step S2 in the first embodiment. Therefore, a detailed description of them is omitted.

As a result, in the second etching step S5, only the SiN layer 2' can be selectively removed as shown in Fig. 14(c). In addition, the SAM 9', which has excellent density and protective performance, covers and protects the surface and side of the _SiO2 layer 1, so that the SiO2 layer ₁ can be prevented from being etched and the etched silicon component can be prevented from precipitating and adhering to the surface of the _SiO2 layer 1. Furthermore, the allowable range of the concentration of silicon contained in the second etching solution such as phosphoric acid can be increased.

[Semiconductor manufacturing equipment]
The semiconductor manufacturing apparatus according to the second embodiment can have basically the same configuration as the semiconductor manufacturing apparatus according to the first embodiment (see FIGS. 6 to 12), and therefore the same reference numerals are used and the description thereof will be omitted.

Third Embodiment
A method and apparatus for manufacturing a semiconductor device according to the third embodiment of the present invention will be described below.
This embodiment is different from the first embodiment in that the surface modification process is performed by a dry method using ultraviolet irradiation. Even with this configuration, reactive sites such as hydroxyl groups are formed in areas where SAM molecules could not be chemically adsorbed, and the SAM molecules are chemically adsorbed, making it possible to form a SAM film with excellent density.

[Method of Manufacturing Semiconductor Device]
The method for manufacturing a semiconductor device according to this embodiment will be described below with reference to Fig. 15. Fig. 15 is a flow chart showing an example of the overall flow of the method for manufacturing a semiconductor device according to the third embodiment of the present invention. Note that the first contact step S101, the removal step S102, the densification treatment step S104, and the rinsing step S105 in the SAM formation step S1' shown in Fig. 15 are the same as those in the first embodiment. Therefore, detailed descriptions of these steps will be omitted.

1. Surface modification step S103'
The surface modification step S103' is a step of modifying the surface of the area where the film defect C occurs in the SAM 9, that is, the area where the SAM 9 is not formed, into an area capable of chemical adsorption by the SAM molecules 5.

In this embodiment, the surface Wf of the substrate W is modified by a dry method using ultraviolet light irradiation. In the case of ultraviolet light irradiation, the ultraviolet light irradiation conditions, such as the wavelength of the light source, the irradiation intensity, and the irradiation time, are not particularly limited as long as the hydroxyl groups 6 can be introduced to the surface of the _SiO2 layer 1 to an extent that the SAM molecules 5 can be chemically adsorbed.

As described in the first embodiment, when surface modification is performed using a wet method, it is preferable to perform a cleaning process and a drying process to remove the surface modification liquid. However, in the dry method using ultraviolet light irradiation in this embodiment, these processes can be omitted. Therefore, compared to the semiconductor device manufacturing method of the first embodiment, the manufacturing efficiency can be improved.

[Semiconductor manufacturing equipment]
Next, the semiconductor manufacturing apparatus according to this embodiment will be described below with reference to the drawings.
The semiconductor manufacturing apparatus of this embodiment is different from the semiconductor manufacturing apparatus of the first embodiment in that the surface modification liquid supply unit 140 in the substrate processing unit 100' is replaced with an ultraviolet irradiation unit 190, as shown in FIG. 16. FIG. 16 is an explanatory diagram showing a schematic configuration of the substrate processing unit 100' according to the third embodiment. In this figure, XYZ orthogonal coordinate axes are displayed as appropriate to clarify the directional relationship of the objects shown. Here, the XY plane represents the horizontal plane, and the +Z direction represents the vertical upward direction. Note that the components having the same functions as those of the semiconductor manufacturing apparatus of the first embodiment are given the same reference numerals and detailed description is omitted.

The ultraviolet ray irradiation section 190 is disposed above the substrate holding section 110 (in the direction indicated by the arrow Z in FIG. 16 ) inside the substrate processing unit 100' so as to be able to irradiate ultraviolet rays onto the front surface Wf of the substrate W held by the substrate holding section 110. The ultraviolet ray irradiation section 190 includes at least a plurality of light source sections 191 and quartz glass 192.

The light source unit 191 shown in FIG. 16 is a line light source, and is arranged so that its longitudinal direction is parallel to the direction indicated by Y in FIG. 16. Furthermore, the light source units 191 are arranged in the direction indicated by the arrow X so that they are equally spaced from one another. However, the light source unit 191 of the present invention is not limited to this form. For example, it may be a form in which ring-shaped light source units with different diameters are arranged concentrically. Furthermore, the light source unit may be a point light source. In this case, it is preferable that the multiple light source units are arranged so that they are equally spaced from one another in a plane.

The type of light source unit 191 is not particularly limited, and for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a potassium lamp, a mercury-xenon lamp, a flash lamp, an excimer lamp, a metal halide lamp, and a UV (ultraviolet)-LED (Light Emitting Diode) can be used. Furthermore, the multiple light source units 191 may be of the same type or different types. When multiple different types of light source units 191 are used, they can be arranged with different peak wavelengths, light intensities, etc.

The quartz glass 192 is disposed between the light source unit 191 and the substrate W. The quartz glass 192 is a plate-like body, and is arranged so as to be parallel to the horizontal direction. The quartz glass 192 is also optically transparent to ultraviolet light, heat-resistant, and corrosion-resistant, and allows the ultraviolet light irradiated from the light source unit 191 to pass through, enabling it to be irradiated onto the surface Wf of the substrate W. Furthermore, the quartz glass 192 can protect the light source unit 191 from the atmosphere inside the chamber 150.

Fourth Embodiment
A method and apparatus for manufacturing a semiconductor device according to the fourth embodiment of the present invention will be described below.
This embodiment differs from the first embodiment in that the surface modification step is performed by a dry method that uses ozone gas or a gas containing moisture. Even with this configuration, reactive sites such as hydroxyl groups are formed in areas where SAM molecules could not be chemically adsorbed, and the SAM molecules are chemically adsorbed, making it possible to form a SAM film with excellent density.

[Method of Manufacturing Semiconductor Device]
The method for manufacturing a semiconductor device according to this embodiment will be described below with reference to FIG. 17. FIG. 17 is a flow chart showing an example of the overall flow of the method for manufacturing a semiconductor device according to the fourth embodiment of the present invention. Note that the first contact step S101, the removal step S102, the densification treatment step S104, and the rinsing step S105 in the SAM formation step S1" shown in FIG. 17 are the same as in the first embodiment. Therefore, detailed descriptions of these steps will be omitted.

1. Surface modification step S103"
The surface modification step S103'' is a step of modifying the surface of a region where the film defect C occurs in the SAM 9, i.e., a region where the SAM 9 is not formed, into a region capable of chemical adsorption by the SAM molecules 5.

In this embodiment, the surface modification of the SiO ₂ layer 1 is performed by a dry method by contact with ozone gas or a gas containing moisture. In the case of surface modification by these methods, hydroxyl groups 6 can be introduced to the surface of the SiO ₂ layer 1 by spraying ozone gas or a gas containing moisture on the surface Wf of the substrate W or exposing it to an atmosphere of these gases. The concentration of ozone contained in the ozone gas and the amount of moisture contained in the gas containing moisture are not particularly limited as long as they can introduce hydroxyl groups 6 to the surface of the SiO ₂ layer 1 to an extent that the SAM molecules 5 can be chemically adsorbed. In addition, the contact time of the ozone gas or the gas containing moisture is also not particularly limited as long as they can introduce hydroxyl groups 6 to the surface of the SiO ₂ layer 1 to an extent that the SAM molecules 5 can be chemically adsorbed.

[Semiconductor manufacturing equipment]
Next, the semiconductor manufacturing apparatus according to the present embodiment will be described below with reference to the drawings. In the following embodiment, the semiconductor manufacturing apparatus will be described as having an ozone gas supply unit for supplying ozone gas, but the gas supply unit for supplying a gas containing moisture may also have a similar configuration.

The semiconductor manufacturing apparatus of this embodiment differs from the semiconductor manufacturing apparatus of the first embodiment in that the surface modification liquid supply unit 140 in the substrate processing unit 100" is replaced with an ozone gas supply unit 193, as shown in FIG. 18. FIG. 18 is an explanatory diagram showing the schematic configuration of the semiconductor manufacturing apparatus of the fourth embodiment. In this figure, XYZ orthogonal coordinate axes are displayed as appropriate to clarify the directional relationships of the illustrated items. Here, the XY plane represents the horizontal plane, and the +Z direction represents the vertical upward direction. Note that components having the same functions as those in the semiconductor manufacturing apparatus of the first embodiment are given the same reference numerals and detailed descriptions are omitted.

The ozone gas supply unit 193 is a means for supplying ozone gas to the surface Wf of the substrate W. As shown in FIG. 18, the ozone gas supply unit 193 has an ozone gas supply source 194, an ozone gas supply pipe 195, a valve 196, a nozzle 197, and an arm 198. The ozone gas supply pipe 195 supplies ozone gas from the ozone gas supply source 194 to the nozzle 197. A valve 196 is provided in the middle of the ozone gas supply pipe 195. The valve 196 is also electrically connected to the control unit 300. This allows the opening and closing of the valve 196 to be controlled by an operation command from the control unit 300. When the valve 196 is opened by an operation command from the control unit 300, ozone gas is pressure-fed to the nozzle 197 through the ozone gas supply pipe 195.

The nozzle 197 is attached to the tip of a horizontally extending arm 198, and is positioned above the spin base 111 when ejecting ozone gas. The arm 198 is connected to the rotation drive unit 170 via a rotation shaft (not shown). The rotation drive unit 170 is electrically connected to the control unit 300, and rotates the arm 198 in response to an operation command from the control unit 300. As the arm 198 rotates, the nozzle 197 also moves.

(Other matters)
In the above description, the most preferred embodiment of the present invention has been described. However, the present invention is not limited to this embodiment. The configurations in the above-described embodiment and each modified example can be changed, modified, substituted, added, deleted, and combined within a range that does not contradict each other.

The following is a detailed description of preferred embodiments of the present invention. However, unless otherwise specified, the materials, amounts, conditions, etc. described in the embodiments do not limit the scope of the present invention.

Example 1
A substrate having a _SiO2 film (thickness 100 nm) formed on its surface was prepared and immersed in an aqueous hydrogen fluoride solution for 1 minute, the volume ratio of which was hydrogen fluoride:DIW=1:100.

Next, the substrate pulled out from the hydrogen fluoride aqueous solution was immersed in a first treatment liquid containing a SAM-forming material for 5 minutes to form a SAM (thickness about 1 nm) on the _SiO2 film surface of the substrate (first contact step). The first treatment liquid was a solution of octadecyltrichlorosilane, a SAM-forming material, dissolved in toluene, a solvent. The content (concentration) of octadecyltrichlorosilane was 5% by mass with respect to the total mass of the first treatment liquid.

Next, the removal liquid was continuously supplied to the substrate removed from the first treatment liquid for one minute to remove any unadsorbed SAM-forming material remaining on the surface of the substrate (removal process). Decane was used as the removal liquid.

Next, the substrate was removed from the removal liquid and immersed in a surface modification liquid for 1 minute (surface modification step). SC-1 (volume ratio of ammonium water ( _NH3 concentration 28%): _hydrogen peroxide water ( _H2O2 concentration 30%): DIW = 1:4:20) was used as the surface modification liquid. Thereafter, the substrate was removed from the surface modification liquid, and the surface on which the SAM was formed was dried by spraying nitrogen gas. The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes.

Furthermore, the dried substrate was immersed in a second treatment liquid containing a SAM-forming material for 5 minutes to form a SAM on the surface of the substrate (second contact step (densification treatment step)). The second treatment liquid used was the same as the first treatment liquid in the first contact step.

Next, toluene was continuously supplied to the substrate removed from the second processing liquid for 1 minute (rinsing process), and then the surface on which the SAM was formed was dried by spraying nitrogen gas onto it. The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes. In this way, a sample according to this embodiment was produced.

Subsequently, the obtained sample was subjected to an etching process. Specifically, the substrate was immersed in an etching solution, and the area on the substrate surface that was not protected by SAM was etched (etching process). As etching conditions, the immersion time in the etching solution (etching process time) was set to 195 seconds so that the etching amount of _SiO2 was about 10 nm. In addition, an aqueous hydrogen fluoride solution was used as the etching solution, and the volume ratio of hydrogen fluoride to DIW was set to hydrogen fluoride:DIW=1:100.

Then, the substrate was removed from the etching solution and immersed in DIW for 0.5 minutes, and then removed from the DIW (DIW rinsing process), and the etched surface was dried by spraying nitrogen gas (drying process). The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes.

(Comparative Example 1)
This comparative example is different from Example 1 in that the removing step, the surface modifying step, and the densifying step (second contact step) were not performed after the first contact step using the first treatment liquid. More details are as follows.

A substrate similar to that in Example 1 was prepared and immersed in an aqueous hydrogen fluoride solution for 1 minute. The aqueous hydrogen fluoride solution used had a volume ratio of hydrogen fluoride to DIW of 1:100.

Next, the substrate was pulled out of the hydrogen fluoride aqueous solution and immersed in a first treatment liquid containing a SAM-forming material for 5 minutes to form a SAM (about 1 nm thick) on the _SiO2 film surface of the substrate. The first treatment liquid was a toluene solvent in which octadecyltrichlorosilane, a SAM-forming material, was dissolved. The content (concentration) of octadecyltrichlorosilane was 5% by mass relative to the total mass of the treatment liquid.

Next, toluene was continuously supplied to the substrate removed from the first treatment liquid for one minute to remove the first treatment liquid remaining on the surface of the substrate, and then nitrogen gas was sprayed onto the surface on which the SAM was formed to dry it. The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes. In this way, a sample according to this comparative example was produced.

Subsequently, the obtained sample was subjected to an etching process. Specifically, the substrate was immersed in an etching solution, and the area on the substrate surface that was not protected by SAM was etched. As etching conditions, the immersion time in the etching solution (etching process time) was set to 195 seconds so that the etching amount of _SiO2 was about 10 nm. In addition, an aqueous hydrogen fluoride solution was used as the etching solution, and the volume ratio of hydrogen fluoride to DIW was set to hydrogen fluoride:DIW=1:100.

Then, the substrate was removed from the etching solution and immersed in DIW for 0.5 minutes, and then removed from the DIW (DIW rinsing process), and the etched surface was dried by spraying nitrogen gas (drying process). The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes.

(Comparative Example 2)
This comparative example is different from Example 1 in that the surface modification step was not carried out after the removal step using decane. More details are as follows.

A substrate similar to that in Example 1 was prepared and immersed in an aqueous hydrogen fluoride solution for 1 minute. The aqueous hydrogen fluoride solution used had a volume ratio of hydrogen fluoride to DIW of 1:100.

Next, the substrate was pulled out of the hydrogen fluoride aqueous solution and immersed in a first treatment liquid containing a SAM-forming material for 5 minutes to form a SAM (about 1 nm thick) on the _SiO2 film surface of the substrate. The first treatment liquid was a toluene solvent in which octadecyltrichlorosilane, a SAM-forming material, was dissolved. The content (concentration) of octadecyltrichlorosilane was 5% by mass relative to the total mass of the treatment liquid.

Next, the substrate was removed from the first treatment liquid and immersed in a removal liquid for one minute to remove any unadsorbed SAM-forming material remaining on the substrate surface. Decane was used as the removal liquid.

Then, the substrate was removed from the removal solution, and the surface on which the SAM was formed was dried by spraying nitrogen gas. The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes.

Furthermore, the dried substrate was immersed in a second treatment liquid containing a SAM-forming material for 5 minutes to form a SAM on the surface of the substrate. The second treatment liquid used was the same as the first treatment liquid in the first contact step.

Next, toluene was continuously supplied to the substrate removed from the second treatment liquid for 1 minute, and the second treatment liquid was then removed. The surface on which the SAM was formed was then dried by spraying nitrogen gas onto it. The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes. In this way, a sample according to this comparative example was produced.

Subsequently, the obtained sample was subjected to an etching process. Specifically, the substrate was immersed in an etching solution, and the area of the substrate not protected by SAM was etched. As etching conditions, the immersion time in the etching solution (etching process time) was set to 195 seconds so that the amount of _SiO2 etched was about 10 nm. As the etching solution, an aqueous hydrogen fluoride solution was used, and the volume ratio of hydrogen fluoride to DIW was set to hydrogen fluoride:DIW=1:100.

Then, the substrate was removed from the etching solution and immersed in DIW for 0.5 minutes, and then removed from the DIW (DIW rinsing process), and the etched surface was dried by spraying nitrogen gas (drying process). The temperature of the nitrogen gas was room temperature, and the drying time was 0.33 minutes.

(SAM Compactness Evaluation)
For each of the samples according to Example 1 and Comparative Examples 1 and 2, the area of the film defects in the SAM was calculated to evaluate the denseness of the SAM.

That is, the SAM of each sample was imaged using an atomic force microscope (AFM) (product name: Dimension Icon, manufactured by Bruker Japan Co., Ltd.), and an observation image (AFM image) of 500 nm square was obtained. Next, each obtained observation image was binarized, and then image processing was performed to map the film defects, and the site (area) of the SAM film defect was identified. In order to identify the site (area) of the SAM film defect by mapping, image processing was performed so that defects located at a depth of less than 1 nm from the SAM surface were mapped, taking into account that the SAM film thickness was about 1 nm. This ensured that the site (area) at a depth of more than 1 nm from the SAM surface, more specifically, the etched site, was mapped as the area of the SAM film defect and was not included in the area. Next, the area of the SAM film defect area identified by image processing was calculated, and the ratio to the area of the entire area in the observation image was calculated. The results are shown in Table 1.

As can be seen from Table 1, the area ratio of the SAM membrane defects in Example 1 was 25.4%, which was the smallest compared to the area ratios of the SAM membrane defects in Comparative Examples 1 and 2, and it was confirmed that the film had good density.

(Evaluation of SAM protection performance)
For each sample according to Example 1 and Comparative Examples 1 and 2, the protective performance of the SAM was evaluated based on the film thickness and water contact angle of the _SiO2 film.

Specifically, the thickness d1 of the _SiO2 film covering the SAM immediately before the etching process and the thickness d2 of the _SiO2 film covering the SAM after all steps were completed were measured using an ellipsometer (product name: Flying MASE XI, manufactured by JA Woollam Co., Ltd.). The results are shown in Table 1.

In addition, the water contact angle θ1 of the _SiO2 film coated on the SAM immediately before the etching process and the water contact angle θ2 of the _SiO2 film coated on the SAM after all steps were completed were measured using a contact angle meter (product name: DMo-701, Kyowa Interface Science Co., Ltd.) based on the sessile drop method. The results are shown in Table 1.

As can be seen from Table 1, in Example 1, the change in the film thickness of the SiO ₂ film before and after etching was from 99.6 nm to 98.8 nm, and the decrease was smaller than in Comparative Examples 1 and 2. In addition, in Example 1, the water contact angle of the SiO ₂ film surface after etching was larger than in Comparative Examples 1 and 2. From these results, it was confirmed that the SAM of Example 1 has superior protective performance for the SiO ₂ film compared to Comparative Examples 1 and 2.

1 _SiO2 layer 2 SiN layer 3 Stack 4 Memory trench 5 SAM molecule 6 Hydroxyl group 7 Water molecule 8 Reverse micelle 9, 9' SAM
110, 210 Substrate holding section 120 Supply section 121 Processing liquid storage section 124 Pressurization section 125 Processing liquid tank 126 First processing liquid tank 127 Second processing liquid tank 130 Removal liquid supply section 131 Removal liquid storage section 135 Removal liquid tank 140 Surface modification liquid supply section 141 Surface modification liquid storage section 144 Pressurization section 145 Surface modification liquid tank 160, 260 Splash prevention cup 170, 270 Swivel drive section 190 Ultraviolet light irradiation section 193 Ozone gas supply section 100, 100', 100" Substrate processing unit 200 Etching processing unit 220 Etching liquid supply section 221 Etching liquid storage section 224 Etching liquid tank 300 Control section S1, S1', S1" SAM formation process S2 Etching process S3 First etching process S4 SAM formation process S5 Second etching step S101 First contact step S102 Removal steps S103, S103', S103" Surface modification step S104 Densification treatment step S105 Rinsing step C Film defect W Substrate Wf Substrate surface

Claims (11)

1. A method for manufacturing a semiconductor device, comprising processing a substrate having a laminate provided on a surface thereof, the method comprising:
The laminate includes a layer to be protected from etching and a layer to be etched which are alternately laminated,
selectively forming a self-assembled monolayer on at least a surface of the layer to be protected;
and selectively etching the layer to be etched using the self-assembled monolayer as a protective layer,
The step of forming a self-assembled monolayer includes:
a first contacting step of contacting a first treatment solution containing molecules capable of forming the self-assembled monolayer with the surface of the layer to be protected to chemically adsorb the molecules;
a removing step of removing the non-chemisorbed molecules from the surface of the protective layer;
a surface modification step of modifying a region on the surface of the protection layer after the removing step where the molecules are not present into a region capable of chemical adsorption by the molecules;
a second contacting step of contacting the surface-modified region with a second processing liquid that contains the molecule and is the same or different from the first processing liquid, thereby chemically adsorbing the molecule;
A method for manufacturing a semiconductor device comprising the steps of: The method further includes a step of etching the layer to be etched to a predetermined depth in a film thickness direction immediately before the step of forming the self-assembled monolayer,
The step of forming a self-assembled monolayer includes:
2. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of forming the self-assembled monolayer also on the side surfaces of the layer to be protected that are exposed by etching the layer to be etched. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein the second contact step is a step of chemically adsorbing the molecules to the area surface-modified in the surface modification step, thereby performing a densification process on the self-assembled monolayer formed in the first contact step. The protective layer is made of silicon dioxide,
the layer to be etched is made of silicon nitride,
the molecule has a functional group capable of forming a siloxane bond with a hydroxyl group,
The surface modification in the surface modification step generates hydroxyl groups in areas where the molecules are not present,
3. The method for manufacturing a semiconductor device according to claim 1, wherein the chemical adsorption of the molecules in the first contact step and the second contact step bonds the molecules to the surface via siloxane bonds with hydroxyl groups on the surface of the protective layer. the surface modification step is a step of contacting a surface modification liquid with a region of the surface of the protection layer after the removal step, the region being free of the molecules;
5. The method for manufacturing a semiconductor device according to claim 4, wherein the surface modifying liquid is a solution which generates hydroxyl groups on the surface of the layer to be protected made of silicon dioxide. The method for manufacturing a semiconductor device according to claim 4, wherein the surface modification step is at least one of the steps of contacting an area on the surface of the protected layer where the molecules are not present with ozone gas, irradiating an area on the surface of the protected layer where the molecules are not present with ultraviolet light, and contacting an area on the surface of the protected layer where the molecules are not present with a gas containing moisture. The method for manufacturing a semiconductor device according to claim 4, wherein the molecule includes octadecyltrichlorosilane. A semiconductor manufacturing apparatus for processing a substrate having a laminate on a surface thereof, comprising:
The laminate includes a layer to be protected from etching and a layer to be etched which are alternately laminated,
a substrate processing unit for selectively forming a self-assembled monolayer on at least a surface of the layer to be protected;
an etching processing unit that selectively etches and removes the layer to be etched using the self-assembled monolayer as a protective layer;
The substrate processing unit includes:
a supply unit that supplies a treatment liquid containing molecules capable of forming the self-assembled monolayer to a surface of the substrate;
a removal liquid supplying unit that supplies a removal liquid to the surface after the supply of the processing liquid to remove the molecules that are not chemically adsorbed;
a surface modification unit that modifies a region of the surface after the molecules are removed by the removal liquid supply unit, the region being free of the molecules, into a region capable of chemical adsorption by the molecules;
Equipped with
The supply unit supplies the treatment liquid to the surface of the substrate after the surface modification by the surface modification unit. the etching processing unit etches the layer to be etched to a predetermined depth in a film thickness direction immediately before the formation of the self-assembled monolayer;
9. The semiconductor manufacturing apparatus according to claim 8, wherein the substrate processing unit forms the self-assembled monolayer also on a side surface of the layer to be protected that is exposed by etching the layer to be etched. The protective layer is made of silicon dioxide,
the layer to be etched is made of silicon nitride,
the molecule has a functional group capable of forming a siloxane bond with a hydroxyl group,
the surface modification unit is a surface modification liquid supply unit that supplies a surface modification liquid to a region where the molecules are not present,
10. The semiconductor manufacturing apparatus according to claim 8, wherein the surface modifying liquid is a solution that generates hydroxyl groups on the surface of the layer to be protected. The protective layer is made of silicon dioxide,
the layer to be etched is made of silicon nitride,
the molecule has a functional group capable of forming a siloxane bond with a hydroxyl group,
10. The semiconductor manufacturing apparatus according to claim 8, wherein the surface modification unit is at least one of an ozone gas supply unit that supplies ozone gas to an area on the surface of the protected layer where the molecules are not present, an ultraviolet irradiation unit that irradiates ultraviolet light to an area on the surface of the protected layer where the molecules are not present, and a gas supply unit that supplies a gas containing moisture to an area on the surface of the protected layer where the molecules are not present.

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