KR20190086236A - Apparatus for atomic layer deposition - Google Patents

Abstract

Disclosed is an atomic layer deposition device. The atomic layer deposition device according to one aspect of the present invention comprises a shower head forming an atomic layer on a substrate and a supporter supporting the substrate. Here, the shower head comprises: a first gas supply unit supplying a first gas to the substrate; an air discharge unit discharging the first gas supplied to the substrate; a purge unit supplying a purge gas to the substrate from which the first gas is discharged; and a second gas supply unit supplying a second gas to the substrate. The first gas is moved from the first gas supply unit to the air discharge unit through a space between the shower head and the substrate. Furthermore, a deceleration unit is formed in which the flow speed of the first gas is reduced when the space formed by the substrate and the shower head is expanded on the moving route of the first gas.

Description

[0001] Apparatus for atomic layer deposition [0002]

The present invention relates to an atomic layer deposition apparatus. More particularly, it relates to an atomic layer deposition apparatus for depositing atomic layers on a substrate.

Thin film deposition technology is widely applied as a method of forming a thin film of an OLED display, a solar cell substrate, or a semiconductor. In particular, in OLED displays, encapsulation thin films are required for low-temperature processes (less than 200 degrees) on large-area substrates.

Conventional sealing thin film technologies include atmospheric pressure CVD (chemical vapor deposition), low pressure chemical vapor deposition (LPCVD), and plasma enhanced chemical vapor deposition (CVD) And a plasma organic chemical vapor deposition method is widely used as a reason for shortening the processing time

Particularly, in OLED displays, there is a demand for a flexible display having a moisture vapor transmission rate (WVTR) characteristic of a sealing film, and an atomic layer deposition method capable of uniformly forming fine patterns. Hereinafter referred to as "ALD process").

The ALD process is a method of forming an atomic layer using chemisorption and desorption processes by the surface saturated reaction of reactants on the substrate surface. Is a possible thin film deposition method.

The ALD process alternately introduces two or more source gases, respectively, and prevents the source gases from mixing in the gaseous state by introducing purge gas, which is an inert gas, between the inlet of each source gas. Through this process, one source gas can be chemically adsorbed on the substrate surface, and subsequently another source gas reacts to generate one layer of atomic layer on the substrate surface. Such a process is repeated at one cycle until a thin film having a desired thickness is formed.

However, in the conventional atomic layer deposition apparatus, it has been difficult to sufficiently secure exposure time for the source gas to reach the substrate from the showerhead nozzle to form a thin film, which poses a problem in forming a uniform thin film on a large area substrate. Further, there is a problem that it is difficult to form a uniform atomic layer on an OLED display substrate having a large step on the surface of the substrate.

Korean Patent Publication No. 10-2016-0137743

An embodiment of the present invention is to provide an atomic layer deposition apparatus capable of ensuring sufficient exposure time of a source gas to a substrate without enlarging the apparatus.

According to an aspect of the present invention, there is provided a plasma processing apparatus including a shower head for forming an atomic layer on a substrate and a support for supporting the substrate, the showerhead including a first gas supply part for supplying a first gas to the substrate, And a second gas supply unit for supplying a second gas to the substrate, wherein the first gas is supplied into the space between the showerhead and the substrate, and the first gas is supplied into the space between the showerhead and the substrate, There is provided an atomic layer deposition apparatus which moves from a first gas supply unit to an exhaust unit and a space formed by the substrate and the shower head in the movement path of the first gas is widened to reduce the flow rate of the first gas.

At this time, the deceleration portion may be disposed between the first gas supply portion and the exhaust portion, and may include a first gas groove recessed in the shower head.

Further, the path through which the first gas is discharged from the first gas groove may be narrower than the path through which the first gas flows into the first gas groove.

Further, the first gas groove may be formed so as to have a larger cross-sectional area toward the exhaust portion.

On the other hand, the exhaust part can extend to cover the side surface of the first gas supply part.

According to the embodiment of the present invention, a uniform atomic layer can be deposited on a substrate having a large area.

In addition, a uniform atomic layer can be formed from the substrate having a large step difference to the sidewall.

1 is a view for explaining driving of an atomic layer deposition apparatus according to an embodiment of the present invention;
2 illustrates a showerhead of an atomic layer deposition apparatus according to an embodiment of the present invention.
3 to 5 are views illustrating a decelerating portion of an atomic layer deposition apparatus according to an embodiment of the present invention.
6 is a graph showing the thickness uniformity of a precursor of a raw material formed using an atomic layer deposition apparatus without a deceleration section.
7 is a graph showing the thickness uniformity of a precursor of a raw material formed using an atomic layer deposition apparatus according to an embodiment of the present invention.
8 is a view illustrating a stepped coated substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention.
9 is a SEM photograph showing a cross section of a stepped coated substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention.
10 is a photograph showing a transparent flexible substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention.
11 is a graph showing transmittance of a visible light region of a substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, when a component is referred to as "comprising ", it means that it can include other components as well, without excluding other components unless specifically stated otherwise. Also, throughout the specification, the term "on" means to be located above or below the object portion, and does not necessarily mean that the object is located on the upper side with respect to the gravitational direction.

In addition, the term " coupled " is used not only in the case of direct physical contact between the respective constituent elements in the contact relation between the constituent elements, but also means that other constituent elements are interposed between the constituent elements, Use them as a concept to cover each contact.

Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, an embodiment of a power generation apparatus according to the present invention will be described in detail with reference to the accompanying drawings. Referring to the accompanying drawings, the same or corresponding components are denoted by the same reference numerals, Is omitted.

Atomic layer Deposition apparatus

FIG. 1 is a view illustrating operation of an atomic layer deposition apparatus according to an embodiment of the present invention, and FIG. 2 is a view showing a shower head of an atomic layer deposition apparatus according to an embodiment of the present invention.

1 and 2, an atomic layer deposition apparatus according to an embodiment of the present invention includes a showerhead 100 for forming an atomic layer on a substrate 10, a support 200 for supporting the substrate 10, The shower head 100 includes a first gas supply unit 110, a first exhaust unit 130, a purge unit 140, a second gas supply unit 150, and a deceleration unit 120.

In one embodiment of the present invention, for relative movement of the substrate 10 relative to the showerhead 100, the substrate 10 may be placed on a support 200 that is capable of reciprocating motion. On the other hand, the relative movement of the substrate 10 with respect to the showerhead 100 may be realized by placing the substrate 10 on the fixed support 200 and reciprocating the showerhead 100. Further, both the showerhead 100 and the support table 200 of the substrate 10 may move.

The first gas supply unit 110, the exhaust unit 130, the purge unit 140 and the second gas supply unit 150 are provided on the substrate 10 to deposit the atomic layer on the substrate 10, As shown in FIG. Referring to FIGS. 1 and 2, the substrate 10 passes through a region where the first gas supply unit 110, the exhaust unit 130, the purge unit 140, and the second gas supply unit 150 are disposed, . Particularly, in the embodiment of the present invention, the deceleration unit 120 may be formed between the first gas supply unit 110 and the first gas exhaust unit 130.

At this time, exhaust portions 132 and 134 may also be formed between the purge portion 140 and the second gas supply portion 150, and between the second gas supply portion 150 and the next first gas supply portion.

The first gas supply unit 110 supplies the first gas to the substrate 10. For example, the first gas supply unit 110 may inject a source precursor such as trimethyl aluminum (TMA) into the substrate 10 as a first gas. TMA is an inorganic layer Al ₂ O ₃ source precursor, and the raw precursor reacts with the surface of the substrate 10 to form a first reaction layer on the surface of the substrate 10.

The exhaust part 130 exhausts the first gas supplied to the substrate 10. [ In this embodiment, when the substrate 10 passes the exhaust portion 130, the exhaust portion 130 can suck and exhaust the raw material precursor in the gaseous state on the substrate 10. [

Referring to FIG. 1, the first gas supply unit 110 and the exhaust unit 130 may be sequentially disposed along the transport direction of the substrate 10. Accordingly, when the first gas, which is the precursor of the raw material, is injected and supplied to the substrate 10 by the first gas supply unit 110 and the first gas is sucked and exhausted from the substrate 10 by the exhaust unit 130, The movement of the first gas from the supply part 110 to the exhaust part 130 is formed. The movement of the first gas may be through the space between the showerhead 100 and the substrate 10.

At this time, the exhaust part 130 may have a structure in which the side of the first gas supply part 110 is extended to cover the side of the first gas supply part 110 such that the first reaction layer is evenly formed on the edge of the substrate 10. Referring to FIG. 2, the exhaust unit 130 may be disposed so as to surround the first gas supply unit 110. Accordingly, a part of the first gas can be moved toward the side of the first gas supplying part 110, that is, toward the edge of the substrate 10. [ Therefore, the first gas can be evenly supplied to the edge of the substrate 10.

The decelerating portion 120 is disposed in the movement path of the first gas to reduce the flow rate of the first gas. Specifically, the deceleration unit 120 may increase the space formed by the substrate 10 and the showerhead 100, thereby reducing the flow rate of the first gas.

3 to 5 are views illustrating a decelerating portion of an atomic layer deposition apparatus according to an embodiment of the present invention.

1 to 5, the deceleration unit 120 is disposed between the first gas supply unit 110 and the exhaust unit 130 and includes first gas grooves 125 and 126 formed concavely in the shower head 100 ). When the first gas is moved from the first gas supply part 110 to the exhaust part 130, the cross sectional area of the first gas is increased when the first gas grooves 125 and 126 are encountered, The moving speed, that is, the flow velocity can be reduced. Also, since the flow of the vortex or the like occurs in the first gas grooves 125 and 126, the contact time of the first gas with the substrate 10 can be increased since the time for which the first gas stays is increased. Therefore, it is possible to ensure a sufficient exposure time of the precursor of the precursor to the substrate 10, so that a uniform atomic layer can be deposited on the large-area substrate 10

3 or 4, a first gas is discharged from the first gas groove 125 to the discharge 124, and a second gas is discharged from the second gas groove 125 through the first gas groove 125, The cross-sectional area of the path to be formed may be narrow. Accordingly, the flow rate of the first gas introduced into the first gas grooves 125, 126 can be lowered as a whole.

For example, the distance between the showerhead 100 and the substrate 10 between the first gas supply part 110 and the first gas grooves 125, 126 may be a distance between the first gas groove 125 and the exhaust part 130 The distance between the shower head 100 and the substrate 10 can be increased. That is, the distance between the showerhead 100 and the substrate 10, that is, the size of the cross-sectional area, can be adjusted by setting a height difference of the surface of the showerhead 100.

4 or 5, the first gas grooves 126 and 127 may be formed so as to have a larger cross-sectional area toward the exhaust part 130. For example, the first gas grooves 126, 127 may be formed with inclined surfaces 126a, 127a which are enlarged toward the exhaust portion 130, so that the flow velocity can be gradually lowered.

In the present embodiment, the deceleration unit 120 is a groove structure formed in the shower head 100, but the present invention is not limited thereto. Alternatively, the deceleration unit 120 may have a structure in which a groove is formed in the shower head 100, Various types of fluid decelerating structures may be included in the decelerator 120, such as a structure for widening the space and decelerating the flow velocity.

The purge portion 140 supplies purge gas to the substrate 10 from which the first gas is exhausted. For example, an inert gas such as oxygen or nitrogen may be injected into the substrate 10 with a purge gas to remove the raw precursor physically adsorbed on the surface of the substrate 10, leaving only a single layer on the substrate 10 .

In this embodiment, oxygen gas to which no plasma is applied may be supplied to the substrate 10. [ Oxygen gas without plasma is used as a purge gas because it does not react with Trimethyl aluminum (TMA), which is a raw material precursor.

The second gas supply unit 150 supplies the second gas to the substrate 10. For example, the second gas supply unit 150 may inject a reaction precursor, such as an oxygen plasma, onto the substrate 10 with a second gas. The reaction precursor may react with the first reaction layer to form a second reaction layer on the surface of the substrate 10. As a result, a single layer of a thin film, for example, an Al ₂ O ₃ thin film composed of the first reaction layer and the second reaction layer, can be deposited on the substrate 10.

In this embodiment, oxygen in a plasma state can be supplied to the substrate 10 as a reaction precursor. The oxygen plasma may include oxygen radicals, oxygen ions, electrons, and the like. The oxygen plasma can be formed by applying plasma power to oxygen.

Experimental Example

Hereinafter, the effect of the atomic layer deposition apparatus according to the present invention will be described by comparing the result of thin film formation by the atomic layer deposition apparatus having the decelerating section and the atomic layer deposition apparatus not having the decelerating section according to an embodiment of the present invention. do.

FIG. 6 is a graph showing the uniformity of the thickness of a precursor of a raw material formed using an atomic layer deposition apparatus without a decelerating portion, FIG. 7 is a graph showing the uniformity of the thickness of a precursor of a precursor formed using an atomic layer deposition apparatus according to an embodiment of the present invention FIG.

The process conditions for performing atomic layer deposition are as follows.

- Al ₂ O ₃ Form a thin film

- Heater temperature: 32 ~ 100 ℃, holding time 10 minutes

- O ₂ flow rate: 400 sccm

- Plasma power: 150W

- Injection speed: 300mm / sec

- Number of processes: 150 ~ 500Cycle

(Here, oxygen is supplied as purge gas.) Oxygen is supplied to the reaction precursor by an oxygen plasma by an electrode or the like to which plasma power is applied, and the jetting speed is a rate of jetting the raw precursor in a gaseous state onto the substrate. )

In the experiment of FIG. 6, the deposition was performed at 32 ° C for Case 1, 50 ° C for Case 2, 100 ° C for Case 3, and 120 ° C for Case 4, and thickness measurements were made at nine points on the substrate.

7, deposition was carried out at 32 ° C for Case 1, 50 ° C for Case 2, 100 ° C for Case 3, 120 ° C for Case 4, 150 ° C for Case 5, and the number of processes in Case 1 to Case 5 was 150 ~ 500 cycles were carried out at 9 points on the substrate.

6, when a thin film formed by an atomic layer deposition apparatus having no decelerating portion as in the prior art is evaluated, there is a large difference of the maximum thickness to the minimum thickness of two times and a deviation of the thickness uniformity of not less than 20% High. Particularly, it can be seen that the heat transfer of the substrate is remarkably reduced at a temperature of 50 ° C or less and the uniformity of the thin film is not very good.

Referring to FIG. 7, when the thin film formed by the atomic layer deposition apparatus according to the embodiment of the present invention is evaluated, the deviation between the minimum thickness and the maximum thickness is not large, and the deviation in thickness uniformity is also very good at 2 to 3% Can be confirmed.

At this time, the linear deposition rate is 2 to 2.1 nm * m / min. Here, the linear deposition rate is defined as deposition thickness (nm) * substrate length (m) / (number of cycles * cycle time (sec)) * 60 (sec).

FIG. 8 is a view illustrating a stepped coated substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention. FIG. 9 is a cross- SEM (scanning electron microscope) photograph showing a cross section of the stepped coated substrate.

As described above, in the present invention, since the deceleration section increases the dwell time of the precursor of the precursor on the substrate 10, the contact time between the precursor precursor and the substrate 10 can be increased. As a result, the thin film can be uniformly formed on the surface of the substrate 10 on which the stepped portion is formed.

8 is a view illustrating a substrate 10 on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention.

8, in order to form the uniform thin film 11 on the stepped substrate 10, the deviation of the laminated thin film thickness t1 formed on the plane and the side wall thin film thickness t2 formed on the side of the step is small do. The sidewall thin film thickness t2 / laminate thin film thickness t1 * 100 is referred to as a step coverage characteristic and may be expressed as a percentage.

FIG. 9 shows a step coverage characteristic in an actual substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention. In the atomic layer deposition apparatus according to an embodiment of the present invention, the step coverage characteristic is about 91.5%, and it can be confirmed that a very uniform thin film is formed also on the substrate having the step difference.

FIG. 10 is a photograph showing transparency of a substrate on which a thin film is deposited by an atomic layer deposition apparatus according to an embodiment of the present invention. FIG. 11 is a graph showing the transparency of a thin film deposited on the substrate by the atomic layer deposition apparatus according to an embodiment of the present invention. And the transparency of the substrate.

Referring to FIG. 10, using the atomic layer deposition apparatus according to an embodiment of the present invention, Al ₂ O ₃ A flexible substrate on which a thin film is formed can be produced. The flexible substrate having the transparency characteristic can be used for an OLED display or the like.

Referring to FIG. 11, Al ₂ O ₃ formed by an atomic layer deposition apparatus according to an embodiment of the present invention The permeability of thin film and PEN (polyethylene-naphthalate) film is compared. The PEN film is an encapsulating material for OLED substrates and is evaluated as a material with transparency of more than 80%. The PEN film and the Al ₂ O ₃ film formed by the atomic layer deposition apparatus of the present invention When the thin films are compared, the Al ₂ O ₃ The characteristics of the thin film having higher transmittance can be confirmed. Therefore, the Al ₂ O ₃ formed by the atomic layer deposition apparatus of the present invention It can be seen that the thin film has suitable characteristics as an encapsulating film of OLED substrate.

It will be apparent to those skilled in the art that various modifications and additions to, or additions to, the components may be made without departing from the scope of the present invention as set forth in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

10: substrate
100: Shower head
110: first gas supply unit
120:
125, 126, 127: a first gas groove
130:
140:
150: second gas supply part
200: Support

Claims (5)

A showerhead for forming an atomic layer on a substrate, and a support for supporting the substrate,
The shower head includes:
A first gas supply unit for supplying a first gas to the substrate;
An exhaust unit for exhausting the first gas supplied to the substrate;
A purge portion for supplying a purge gas to the substrate on which the first gas is exhausted; And
And a second gas supply unit for supplying a second gas to the substrate,
The first gas moves from the first gas supply unit to the exhaust unit in a space between the showerhead and the substrate,
Wherein a space formed by the substrate and the showerhead is widened in the movement path of the first gas to reduce a flow rate of the first gas.
3. The method of claim 2,
Wherein,
And a first gas groove formed between the first gas supply unit and the exhaust unit and recessed in the showerhead. 3. The method of claim 2,
Wherein a path through which the first gas is discharged from the first gas groove is narrower than a path through which the first gas flows into the first gas groove.
3. The method of claim 2,
The first gas groove
And a cross-sectional area thereof is increased toward the exhaust part.
The method according to claim 1,
Wherein the exhaust unit extends to cover a side surface of the first gas supply unit.

Images