US20180265989A1

US20180265989A1 - Substrate treatment apparatus and substrate treatment method

Info

Publication number: US20180265989A1
Application number: US15/700,694
Authority: US
Inventors: Yasuhito Yoshimizu; Yuya Akeboshi; Fuyuma ITO; Hakuba KITAGAWA
Original assignee: Toshiba Memory Corp
Current assignee: Kioxia Corp
Priority date: 2017-03-17
Filing date: 2017-09-11
Publication date: 2018-09-20

Abstract

According to an embodiment, a substrate treatment apparatus includes a noble metal-containing member having a concave-convex surface including a noble metal, and a liquid chemical supply member to supply a liquid chemical. While convex portions of the concave-convex surface are contact with a predetermined surface of a metal, the liquid chemical is supplied onto the surface of the metal to remove the metal with etching.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2017-053310, filed on Mar. 17, 2017; the entire contents of which are incorporated herein by reference.

FIELD

Embodiments of the present invention relate to a substrate treatment apparatus and a substrate treatment method.

BACKGROUND

In one of substrate treatment methods, there is included a wet etching removing a metal film formed on a pattern of a substrate. In this wet etching, when the metal film includes, for example, tungsten, its etching rate is low although tungsten can be dissolved in an alkaline liquid chemical. When another liquid chemical is used in order to enhance the dissolution rate, there is a possibility of damage to the pattern.
A problem to be solved by the present invention is to provide a substrate treatment apparatus and a substrate treatment method capable of enhancing an etching rate of a metal film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a first embodiment;

FIG. 2 is an expanded view having a part of the bottom face of a noble metal-containing member expanded;

FIG. 3A is a cross-sectional view showing a state before etching of a substrate;

FIG. 3B is a cross-sectional view showing a state after he etching of the substrate;

FIG. 4 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a second embodiment;

FIG. 5 is a schematic diagram for explaining an etching step of a substrate according to the second embodiment;

FIG. 6 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a third embodiment;

FIG. 7 is an expanded view having a contact portion between a substrate and the noble metal-containing member expanded;

FIG. 8 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a fourth embodiment; and

FIG. 9 is an expanded view having the essential part of the substrate treatment apparatus shown in FIG. 8 expanded.

DETAILED DESCRIPTION

Embodiments will now be explained with reference to the accompanying drawings. The present invention is not limited to the embodiments.

First Embodiment

FIG. 1 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a first embodiment. A substrate treatment apparatus 1 shown in FIG. 1 is a treatment apparatus for a substrate 100 and includes a noble metal-containing member 10, a liquid chemical supply nozzle 20 (liquid chemical supply member), a retention member 30 (first retention member) and a retention member 31 (second retention member).
FIG. 2 is an expanded view having a part of the bottom face of the noble metal-containing member 10 expanded. In the present embodiment, the noble metal-containing member 10 is constituted of a porous member, for example, made of polyvinyl alcohol (PVA), urethane, Teflon® or an ion exchange resin. As shown in FIG. 2, the bottom face of the noble metal-containing member 10 is formed into a concave-convex surface. When a pitch p between convex portions on this concave-convex surface is too narrow, a liquid chemical 200 hardly comes into the concave-convex surface. On the other hand, when the pitch p is too wide, it is concerned that contact between the noble metal-containing member 10 and the substrate 100 is insufficient. Therefore, the pitch p preferably falls within a range of tens of micrometers. Moreover, when the height of the concave-convex surface is too low, the liquid chemical 200 hardly comes into the concave-convex surface. Therefore, the height is preferably not less than tens of micrometers.
A noble metal film 11 that comes into partial contact with the substrate 100 is provided on the aforementioned concave-convex surface. The noble metal film 11 preferably includes, for example, at least any of platinum (Pt), gold (Au), silver (Ag) and palladium (Pd). Moreover, the noble metal film 11 is formed on the aforementioned concave-convex surface, for example, by a sputtering method, an electroless plating method, a CVD (Chemical Vapor Deposition) method, an ALD (Atomic Layer Deposition) method or the like. When the noble metal film 11 is formed by the electroless plating method, an ion exchange resin is preferably used for the noble metal-containing member 10 in order to enhance adhesion to the noble metal film 11. Moreover, when the noble metal film 11 is formed on a porous member using Teflon® by the sputtering method, by beforehand performing plasma processing on the surface of Teflon®, adhesion to the noble metal film 11 can be enhanced while maintaining durability to the liquid chemical 200.
Returning to FIG. 1, in the present embodiment, the liquid chemical supply nozzle 20 includes a nozzle that ejects the liquid chemical 200 which is alkaline toward a contact portion between the substrate 100 and the aforementioned noble metal film 11. The liquid chemical 200 is preferably a mixed solution of an alkaline solution and an oxidizing agent. For the alkaline solution, for example, choline, aqueous ammonia and sodium hydroxide can be used. Meanwhile, for the oxidizing agent, for example, aqueous hydrogen peroxide and aqueous ozone can be used. Notably, in order to enhance an etching effect, the temperature of the liquid chemical 200 supplied from the liquid chemical supply nozzle 20 is preferably close to 80° C. It should be noted that the liquid chemical 200 is not limited to be alkaline but may be acidic in accordance with a component included in the noble metal film 11 to be etched.
The retention member 30 elevatably retains the noble metal-containing member 10. The retention member 30 is joined, for example, to an elevation mechanism or constituted as a part of the elevation mechanism.
The retention member 31 ratably retains the substrate 100. The retention member 31 is joined, for example, to a rotation mechanism or constituted as a part of a rotary shaft of the rotation mechanism.
Next, referring to FIG. 3A and FIG. 3B, a structure of the substrate 100 which is an etching target is described. FIG. 3A shows a state of the substrate 100 before etching. FIG. 3B shows a state of the substrate 100 after the etching.
As shown in FIG. 3A, a metal film 101 is provided in the substrate 100 before etching. The metal film 101 is provided on a stacked body 102. The metal film 101 is a mask formed on the stacked body 102 for forming a pattern (in the present embodiment, a slit penetrating the stacked body 102) in the stacked body 102 and includes, for example, tungsten. As shown in FIG. 3B, this metal film 101 is removed with etching by the substrate treatment apparatus 1.
In the stacked body 102, insulator films 102 a and conductor films 102 b are alternately provided. The insulator films 102 a include, for example, silicon oxide (SiO₂). The conductor films 102 b include tungsten the same as the metal film 101. The conductor films 102 b can be used, for example, for word lines of a three-dimensional memory. Notably, the structure of the substrate 100 is not limited to the aforementioned structure but may be any structure in which some pattern is formed.
Hereafter, a substrate treatment method using the substrate treatment apparatus 1 according to the present embodiment is described. Herein, an etching step of the substrate 100 is described.
First, as shown in FIG. 1, by moving down the noble metal-containing member 10 using the retention member 30 with respect to the substrate 100 retained on the retention member 31, the noble metal film 11 of the noble metal-containing member 10 is contact with the metal film 101 of the substrate 100. At this time, in order to prevent damage to the stacked body 102 of the substrate 100, in other words, the pattern, it is desirable for pressure of the noble metal-containing member 10 exerted on the substrate 100 to be as small as possible.
Next, the liquid chemical supply nozzle 20 ejects the liquid chemical 200 toward the contact portion between the noble metal film 11 and the metal film 101 of the substrate 100. At this time, as shown in FIG. 3A, the noble metal film 11 is provided on the concave-convex surface of the noble metal-containing member 10. Therefore, the convex portions of the noble metal film 11 are contact with respective portions of the metal film 101 which are provided on the convex portions of the pattern. The liquid chemical 200 comes into gaps between recess parts of the noble metal film 11 and the metal film 101, and is supplied onto the metal film 101 provided on the convex portions of the pattern. Thereby, galvanic corrosion takes place to promote etching of the metal film 101.
After that, after the noble metal-containing member 10 is elevated using the retention member 30, the substrate 100 is rotated using the retention member 31. After that, the noble metal-containing member 10 is moved down again to supply the liquid chemical 200 from the liquid chemical supply nozzle 20. Thereby, the metal film 101 formed at a different position from the previous one is etched. As above, all the unnecessary metal film 101 is removed.
According to the present embodiment described above, etching is performed with the alkaline liquid chemical 200 in the state where the convex portions of the noble metal film 11 are partial contact with the metal film 101 of the substrate 100. Hence, while the metal film 101 in contact with the noble metal film 11 is removed through galvanic corrosion at a high etching rate, the insulator films 102 a and the conductor films 102 b not in contact with the noble metal film 11 are not removed. Therefore, the etching rate of the metal film 101 can be enhanced without damaging the pattern of the substrate 100. In particular, in the present embodiment, even if the metal film 101 to be etched and the conductor films 102 b to be protected include the same metal (tungsten in the present embodiment), only the metal film 101 can be selectively etched.
Moreover, in the present embodiment, since the porous member is used for the noble metal-containing member 10, the liquid chemical 200 can also be impregnated in this porous member. For example, when the liquid chemical 200 is directly supplied onto this porous member from the liquid chemical supply nozzle 20, the liquid chemical 200 can be impregnated therein. In this case, since a new (unreacted) liquid chemical 200 is always supplied onto the contact portion between the noble metal film 11 and the metal film 101, the metal film 101 can be more surely removed. Notably, in the case where the liquid chemical 200 is directly supplied to the noble metal-containing member 10, in order not to prevent the liquid chemical 200 from permeating from the concave-convex surface of the noble metal-containing member 10, the noble metal film 11 is preferably formed partially on the concave-convex surface, not on the entire concave-convex surface. It should be noted that when the noble metal film 11 itself is a porous member, the liquid chemical 200 can permeate the noble metal film 11 even when the concave-convex surface is not formed on the noble metal-containing member 10.
Notably, in the present embodiment, in order that he liquid chemical can be easily supplied onto the surface of the metal film 101, the recesses of the noble metal-containing member 10 having the concave-convex surface are not contact with the metal film, but a space is provided between the metal film 101 and the surface of the noble metal-containing member 10. Nevertheless, the surface of the noble metal-containing member 10 is not necessarily rough.
As long as the liquid chemical 200 can be supplied onto the metal film 101, even when the noble metal-containing member 10 having a flat surface of noble metal is contact with the metal film 101, a sufficient etching effect can be expected. For example, using the substrate treatment apparatus 1 in FIG. 1, the metal film 101 may be contact with the surface of the noble metal film 11 of the noble metal-containing member 10 while directly supplying the liquid chemical 200 between the patterns of the metal film 101 of the substrate 100 to rotate the substrate. Thereby, the metal film 101 can be removed with etching.
Moreover, while in the present embodiment, the noble metal-containing member 10 is contact with the pattern of the metal film 101 on the substrate 100, it may be contact with another metal surface, for example, a metal film provided in a bevel part of the wafer-like substrate 100. In this case, the metal film provided in the bevel part of the substrate 100 can be peeled off.

Second Embodiment

FIG. 4 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a second embodiment. A substrate treatment apparatus 2 shown in FIG. 4 includes the noble metal-containing member 10, a tank 40 (liquid chemical supply member), a retention member 50 (first retention member) and a retention member 51 (second retention member). Notably, the structures of the noble metal-containing member 10 and the substrate 100 are similar to those in the first embodiment, and their detailed description is omitted.
At the bottom part of the tank 40, supply ports 41 are provided. The tank 40 stores the alkaline liquid chemical 200 supplied from the supply ports 41. The noble metal-containing member 10 and the substrate 100 are immersed in this liquid chemical 200.
The retention member 50 retains the noble metal-containing member 10 conveyably to the tank 40. The retention member 50 is joined, for example, to a conveyance mechanism for the noble metal-containing member 10 or constituted as a part of the conveyance mechanism.
The retention member 51 retains the substrate 100 conveyably to the tank 40. The retention member 51 is joined, for example, to a conveyance mechanism for the substrate 100 or constituted as a part of the conveyance mechanism.
Hereafter, a substrate treatment method using the substrate treatment apparatus 2 according to the present embodiment is described using FIG. 5. Also similarly to the first embodiment, an etching step of the substrate 100 is herein described. FIG. 5 is a schematic diagram for explaining an etching step of the substrate 100 according to the second embodiment.
First, the noble metal-containing member 10 is conveyed into the tank 40 using the retention member 50, and the substrate 100 is conveyed into the tank 40 using the retention member 51. In the tank 40, the noble metal-containing member 10 and the substrate 100 are contact with each other. Specifically, the noble metal film 11 of the noble metal-containing member 10 is partial contact with the metal film 101 of the substrate 100. At this time, in order to prevent damage to the stacked body 102 of the substrate 100, it is desirable for pressure at the contact portion between the metal film 101 and the noble metal film 11 to be as small as possible.
Next, the alkaline liquid chemical 200 is supplied into the tank 40 from the supply ports 41. Upon the liquid chemical 200 being stored in the tank 40, as shown in FIG. 4, the noble metal-containing member 10 and the substrate 100 are immersed in the liquid chemical 200. This liquid chemical 200 comes into the gaps between the noble metal film 11 and the metal film 101. Therefore, similarly to the first embodiment, galvanic corrosion takes place to promote etching of the metal film 101. After that, the noble metal-containing member 10 and the substrate 100 are taken out of the tank 40, and the noble metal-containing member 10 and another substrate 100 are conveyed into the tank 40.
According to the present embodiment described above, similarly to the first embodiment, by etching the metal film 101 through galvanic corrosion, the metal film 101 can be removed at a high etching rate while preventing damage to the pattern of the substrate 100.
Moreover, in the present embodiment, the metal film 101 is removed by batch in the tank 40. Accordingly, an etching time can be shortened as compared with the first embodiment.

Third Embodiment

FIG. 6 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a third embodiment. A substrate treatment apparatus 3 shown in FIG. 6 includes the noble metal-containing member 10, the liquid chemical supply nozzle 20 and a drive mechanism 60. Notably, the structures of the liquid chemical supply nozzle 20 and the substrate 100 are similar to those in the first embodiment, and their detailed description is omitted.
The shape of the noble metal-containing member 10 is the shape of a belt that retains a plurality of substrates 100. On the surface of the belt, the noble metal film 11 (not shown in FIG. 6) is formed. The noble metal film 11 may be deposited on a soft member, for example, of silicone rubber or the like. Otherwise, the noble metal-containing member 10 itself may be formed as a thin belt of the noble metal film 11.
The drive mechanism 60 is attached to the noble metal-containing member 10. With the drive mechanism 60 rotating, the noble metal-containing member 10 moves in one direction X below the liquid chemical supply nozzle 20. In other words, the drive mechanism 60 conveys the plurality of substrates 100 in a belt conveyer manner.
Hereafter, a substrate treatment method using the substrate treatment apparatus 3 according to the present embodiment is described. Also similarly to the first embodiment, an etching step of the substrate 100 is herein described.
First, the substrates 100 are reversed and placed on the noble metal-containing member 10. Hence, as shown in FIG. 7, the metal film 101 of the substrate 100 comes into contact with the noble metal film 11 of the noble metal-containing member 10. Subsequently, the drive mechanism 60 drives the noble metal-containing member 10 to convey the substrates 100. When the substrate 100 comes right below the liquid chemical supply nozzle 20, the liquid chemical supply nozzle 20 ejects the liquid chemical 200.
The ejected liquid chemical 200 spreads from the substrate 100 to the noble metal film 11. At this time, the liquid chemical 200 also comes into the gaps between the metal film 101 and the noble metal film 11. Hence, similarly to the aforementioned other embodiments, galvanic corrosion takes place to promote etching of the metal film 101.
After that, upon the drive mechanism 60 driving the noble metal-containing member 10, the next substrate 100 comes right below the liquid chemical supply nozzle 20, and the metal film 101 provided on the substrate 100 is similarly removed. As above, the metal films 101 respectively provided on the plurality of substrates 100 placed on the noble metal-containing member 10 are continuously removed.
Also in the present embodiment described above, by etching the metal film 101 through galvanic corrosion, the metal film 101 can be removed at a high etching rate while preventing damage to the pattern of the substrate 100.
Moreover, in the present embodiment, continuous etching of the plurality of substrates 100 is possible. Accordingly, an operation rate of the device can be improved.

Fourth Embodiment

FIG. 8 is a schematic diagram showing a schematic configuration of a substrate treatment apparatus according to a fourth embodiment. FIG. 9 is an expanded view having the essential part of a substrate treatment apparatus 4 shown in FIG. 8 expanded.
As shown in FIG. 8 and FIG. 9, the substrate treatment apparatus 4 according to the present embodiment includes the noble metal-containing member 10, the liquid chemical supply nozzle 20, a retention member 70 (first retention member) and a retention member 71 (second retention member). Notably, the structures of the liquid chemical supply nozzle 20 and the substrate 100 are similar to those in the first embodiment, and their detailed description is omitted.
The noble metal-containing member 10 is formed into a disc shape on which a plurality of substrates 100 are retained. The upper face of the noble metal-containing member 10 is a concave-convex surface. As shown in FIG. 9, the noble metal film 11 is provided on this concave-convex surface. Notably, similarly to the third embodiment, the noble metal-containing member 10 may be deposited on a soft member of silicone rubber or the like. Otherwise, the noble metal-containing member 10 itself may be formed as a thin disc.
The retention member 70 rotably retains the noble metal-containing member 10. The retention member 70 is joined, for example, to a rotation mechanism or constituted as a part of the rotation mechanism.
The retention member 71 retains a plurality of substrates 100 rotably in the same direction and synchronously to the noble metal-containing member 10. The retention member 71 is joined, for example, to the same rotation mechanism as that for the retention member 70 or constituted as a part of the rotation mechanism.
Hereafter, a substrate treatment method using the substrate treatment apparatus 4 according to the present embodiment is described. Also similarly to the first embodiment, an etching step of the substrate 100 is herein described.
First, the plurality of substrates 100 retained on the retention member 71 are placed on the noble metal-containing member 10. At this time, the substrates 100 are reversed and retained on the retention member 71 such that the metal films 101 are in contact with the noble metal film 11.
Subsequently, the noble metal-containing member 10 is rotated using the retention member 70. Synchronously to the rotation of the noble metal-containing member 10, the substrates 100 are also rotated in the same direction. Therefore, almost no shearing stress is exerted between the noble metal-containing member 10 and the substrates 100.
Next, the liquid chemical supply nozzle 20 ejects the alkaline liquid chemical 200 toward the center of the noble metal-containing member 10. The ejected liquid chemical 200 spreads toward the circumference of the noble metal-containing member 10 due to centrifugal force originated from the rotation of the noble metal-containing member 10. At this time, the liquid chemical 200 also comes into the gaps between the metal films 101 and the noble metal film 11. Therefore, similarly to the aforementioned other embodiments, galvanic corrosion takes place to promote etching of the metal film 101.
Also in the present embodiment described above, the etching rate is enhanced by bringing the metal films 101 into contact with the noble metal film 11. Moreover, in the present embodiment, since the substrates 100 rotate in the same direction and synchronously to the noble metal-containing member 10, almost no shearing stress is exerted between these. Therefore, damage to the pattern of the substrate 100 can be prevented.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

1. A substrate treatment apparatus comprising:

a noble metal-containing member having a concave-convex surface including a noble metal; and

a liquid chemical supply member to supply a liquid chemical, wherein

while convex portions of the concave-convex surface are contact with a predetermined surface of a metal, the liquid chemical is supplied onto the surface of the metal, and the metal is removed with etching.

2. The substrate treatment apparatus according to claim 1, wherein

the concave-convex surface including the noble metal is a concave-convex surface having a porous material on its surface.

3. The substrate treatment apparatus comprising:

a noble metal-containing member having a porous material including noble metal on its surface; and

a liquid chemical supply member to supply a liquid chemical, wherein

while the porous material is contact with a predetermined surface of a metal, the liquid chemical is supplied onto the surface of the metal, the metal is removed with etching.

4. The substrate treatment apparatus according to claim 1, wherein

the predetermined surface of the metal is formed on a surface of a plurality of convex portions of a pattern provided on a substrate.

5. The substrate treatment apparatus according to claim 1, further comprising:

a first retention member to elevatably retain the noble metal-containing member; and

a second retention member to rotably retain the predetermined surface of the metal.

6. The substrate treatment apparatus according to claim 1, wherein

the noble metal includes at least any of platinum (Pt), gold (Au), silver (Ag) and palladium (Pd).

7. The substrate treatment apparatus according to claim 1, wherein

the liquid chemical supply member is a tank to store the liquid chemical, the device further comprising:

a first retention member to retain the noble metal-containing member conveyably to the tank; and

a second retention member to retain a substrate conveyably to the tank.

8. The substrate treatment apparatus according to claim 1, wherein

a shape of the noble metal-containing member is a shape of a belt that retains a plurality of substrates, the device further comprising

a drive mechanism to move the noble metal-containing member in one direction below the liquid chemical supply member.

9. The substrate treatment apparatus according to claim 1, further comprising:

a first retention member to rotably retain the noble metal-containing member; and

a second retention member to retain a plurality of substrates on the noble metal-containing member rotably in the same direction and synchronously to the noble metal-containing member.

10. A substrate treatment method comprising:

forming a metal film on a pattern of a substrate; and

removing the metal film with etching, by supplying a liquid chemical to the metal film in a state that a noble metal is contact with the metal film.

11. The substrate treatment method according to claim 10, wherein

a surface of the pattern is exposed by removing the metal film with etching.

12. The substrate treatment method according to claim 10, wherein

the liquid chemical is alkaline.

13. The substrate treatment method according to claim 10, wherein

the metal film includes tungsten.

14. The substrate treatment method according to claim 10, wherein

the noble metal has a concave-convex surface, and the liquid chemical is supplied to the metal film in a state that the concave-convex surface is contact with the metal film.

15. The substrate treatment method according to claim 10, wherein

the noble metal is porous, and the liquid chemical is supplied to the metal film in a state that the porous noble metal is contact with the metal film.

16. The substrate treatment method according to claim 10, wherein

the pattern includes a stacked body having conductor films including the same metal as that of the metal film and insulator films alternately stacked.