SUBSTRATE PROCESSING APPARATUS

Provided is a reactor capable of improving the symmetry of the profile of a thin film deposited on a substrate with an asymmetric exhaust structure, wherein a distance between a gas flow control ring (FCR) and an exhaust unit on one side where an exhaust port is located is greater than a distance between the FCR and the exhaust unit on the opposite side of the exhaust port.

BACKGROUND

One or more embodiments of the disclosure relate to a substrate processing apparatus, and more particularly, to a substrate processing apparatus having an asymmetric exhaust structure in order to improve the symmetry of the profile of a thin film deposited on a substrate.

2. Description of the Related Art

As shown inFIG. 1, in a substrate processing apparatus1equipped with a plurality of reactors2, an exhaust port3of each reactor2is located on an outer wall (in the case ofFIG. 1, a sidewall) of the reactor2, and may be formed to penetrate an outer wall of the substrate processing apparatus1. As an example, the exhaust port3on the reactor2may be configured to penetrate perpendicularly a corner surface where two outer walls4and5of the substrate processing apparatus1intersect. One or more of exhaust ports3of the plurality of reactors2may be connected to each other through common exhaust lines6and7at the side or bottom of the substrate processing apparatus1, and may be connected to an exhaust pump8via the common exhaust lines6and7. Each reactor2may share the exhaust pump8through the common exhaust lines6and7, as shown inFIG. 1, and may be connected to a separate exhaust line (not shown) for each reactor and may be connected to respective exhaust pump8. A residual gas after the reaction in each reactor2may be exhausted to the outside through the exhaust port3, the exhaust lines6and7, and the exhaust pump8.

However, because the exhaust port3is located asymmetrically with respect to the center of the reactor2, an exhaust flow in the reactor2is asymmetric with respect to the center of the reactor2, which is the main cause of the asymmetry of a deposition profile of a thin film on a substrate (an asymmetric film profile).

FIG. 2shows that the exhaust port3is asymmetrically arranged with respect to the center of the reactor2, so that the thickness profile of the thin film on the substrate is asymmetric.

In general, in one reactor2, the exhaust flow near the exhaust port3is faster than the exhaust flow at the opposite side of the exhaust port3. Accordingly, the thickness (−) of the thin film on the substrate near the exhaust port3is less than the thickness (+) of the thin film on the substrate at a position far from the exhaust port3. Also, due to a limited purge period performed after a deposition/reactive gas supply period, a relatively large amount of deposition gas/reactive gas accumulates in a portion of a reaction space far from the exhaust port3compared to a portion close to the exhaust port3. Accordingly, a thin film is deposited thicker in the portion far from the exhaust port3. Such an asymmetric thin film thickness may cause a process failure in a subsequent process or deteriorate compatibility with the subsequent process.

SUMMARY

One or more embodiments include a substrate processing apparatus capable of reducing the asymmetry of a deposited film profile due to the asymmetry of an exhaust flow.

One or more embodiments include a substrate processing apparatus having an asymmetric exhaust structure to improve the symmetry of the thickness profile of a thin film deposited on a substrate.

According to one or more embodiments, a reactor includes: an upper body including a gas supply unit and an exhaust unit; a substrate support device; and an inner ring surrounding the substrate support device and arranged between the substrate support device and a sidewall of the reactor, and a reaction space is formed between the gas supply unit and the substrate support device, wherein the exhaust unit includes: an exhaust port located on a first side of the reactor; an exhaust duct configured to provide an exhaust space therein; an exhaust hole connecting the exhaust space of the exhaust duct to the exhaust port and arranged inside the upper body; and an exhaust channel extending from the reaction space to the exhaust port through the inner space of the exhaust duct and the exhaust hole, wherein a first step toward the reaction space is formed below the upper body, the inner ring is seated on the first step, a vertical distance between the exhaust duct and the inner ring on the first side is greater than a vertical distance between the exhaust duct and the inner ring on the second side, and the second side is opposite to the first side with respect to the center of the upper body.

According to an example of the reactor, a vertical distance between the exhaust duct and the inner ring on the first side may be greater than a vertical distance between the substrate support device and the gas supply unit.

According to another example of the reactor, a vertical distance between the exhaust duct and the inner ring on the second side may be greater than a vertical distance between the substrate support device and the gas supply unit.

According to another example of the reactor, a vertical distance between the exhaust duct and the inner ring on the second side may be less than a vertical distance between the substrate support device and the gas supply unit.

According to another example of the reactor, during an exhaust operation, a gas exhaust flow at the first side may be faster than a gas exhaust flow at the second side.

According to another example of the reactor, during an exhaust operation, an exhaust pressure gradient may be strengthened from the second side to the first side within the reaction space.

According to another example of the reactor, a gas exhaust flow rate may be adjusted by adjusting at least one of a vertical distance between the exhaust duct and the inner ring on the first side and a vertical distance between the exhaust duct and the inner ring on the second side.

According to a further example of the reactor, the uniformity or symmetry of the thickness of a thin film deposited on a substrate may be controlled by adjusting at least one of a vertical distance between the exhaust duct and the inner ring on the first side and a vertical distance between the exhaust duct and the inner ring on the second side.

According to another example of the reactor, an upper surface of the inner ring is inclined to be higher at the second side than at the first side, and a gas exhaust flow rate may be adjusted by adjusting an inclination of the upper surface of the inner ring.

According to a further example of the reactor, an outer ring may be seated on a first step below the upper body, a second step toward the reaction space may be formed in the outer ring, and the inner ring may be seated on a second step of the outer ring.

According to a further example of the reactor, a vertical distance between the exhaust duct and the outer ring at the second side may be greater than a vertical distance between the exhaust duct and the inner ring at the second side.

According to a further example of the reactor, a vertical distance between the exhaust duct and the outer ring at the first side may be greater than a vertical distance between the exhaust duct and the inner ring at the first side.

According to another example of the reactor, an exhaust channel inside the upper body may be formed to surround the reaction space.

According to another example of the reactor, the exhaust channel may have a greater width at the first side than at the second side.

According to one or more embodiments, a gas flow control ring (FCR) includes a structure in which an upper surface of the gas flow control ring is higher at the second side than at the first side and is inclined from a second side toward a first side, and the second side is opposite to the first side with respect to the center of the gas flow control ring.

According to another example of the gas flow control ring, the gas flow control ring is seated in a reactor to surround a substrate support device, and a gas exhaust flow rate in the reactor may be adjusted according to an inclination of the upper surface of the gas flow control ring.

According to one or more embodiments, a substrate processing apparatus includes an outer chamber providing an inner space; at least one reactor arranged in the inner space, which is one of the aforementioned reactors; a deposition gas source configured to supply a deposition gas to the at least one reactor; a reactive gas source configured to supply a reactive gas to the at least one reactor; and at least one exhaust pump connected to an exhaust port of the at least one reactor through an exhaust line.

DETAILED DESCRIPTION

In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to one of ordinary skill in the art.

It will be understood that, although the terms first, second, etc. may be used herein to describe various members, components, regions, layers, and/or sections, these members, components, regions, layers, and/or sections should not be limited by these terms. These terms do not denote any order, quantity, or importance, but rather are only used to distinguish one component, region, layer, and/or section from another component, region, layer, and/or section. Thus, a first member, component, region, layer, or section discussed below could be termed a second member, component, region, layer, or section without departing from the teachings of embodiments.

Embodiments of the disclosure will be described hereinafter with reference to the drawings in which embodiments of the disclosure are schematically illustrated. In the drawings, variations from the illustrated shapes may be expected because of, for example, manufacturing techniques and/or tolerances. Thus, the embodiments of the disclosure should not be construed as being limited to the particular shapes of regions illustrated herein but may include deviations in shapes that result, for example, from manufacturing processes.

Although a deposition device of a semiconductor or a display substrate is described herein as the substrate processing apparatus, it is to be understood that the disclosure is not limited thereto. The substrate processing apparatus may be any device necessary for performing deposition of a material for forming a thin film, and may refer to a device in which a raw material for etching or polishing the material is uniformly supplied. Hereinafter, for convenience of description, it is assumed that the substrate processing apparatus is a semiconductor deposition device.

FIG. 3is a view of a conventional reactor2. The reactor2may be arranged inside a chamber of the substrate processing apparatus.

The reactor2according to an embodiment may include an upper body40. In addition, the reactor2may include a substrate support device70, and an inner ring15surrounding the substrate support device70and arranged between the substrate support device70and a sidewall50of the reactor2in an inner space of the reactor2.

The reactor2may be a reactor in which an atomic layer deposition (ALD) or chemical vapor deposition (CVD) process is performed.

The upper body40of the reactor2may include a gas inlet unit30, a gas supply unit31, and an exhaust unit.

The gas supply unit31may be implemented in, for example, a lateral flow-type assembly structure or a showerhead-type assembly structure. The gas supply unit31may form a reaction space R together with the substrate support device70.

A base of the gas supply unit31may include a plurality of gas supply holes formed (e.g., in a vertical direction) to eject a process gas. The gas supply unit31includes a metal material and may serve as an electrode during a plasma process. During the plasma process, a high frequency (RF) power source may be electrically connected to the gas supply unit31functioning as one electrode. In more detail, an RF rod80connected to the RF power source may pass through a reactor wall and be connected to the gas supply unit31. In this case, the substrate support device70may function as the other electrode.

The exhaust unit may include an exhaust port3, an exhaust duct60, an exhaust hole14, and an exhaust channel.

The exhaust port3may be located on one side of the reactor2according to an exhaust method, and may be upward exhaust or downward exhaust or side exhaust. For example, as shown inFIG. 3, the exhaust port3may be located on the side of the reactor2. It should be noted that although a lateral exhaust structure is used as an example of the exhaust method described herein, the disclosure is not limited thereto. The exhaust port3may be located on an upper surface of the reactor2for upward exhaust, or may be located below the reactor2for downward exhaust. Hereinafter, for convenience, it will be described on the premise that side exhaust of the reactor2is used.

A first step S1toward the reaction space R may be formed below the upper body40. The first step S1may have an upper surface, a lower surface, and a side surface connecting the upper surface to the lower surface. The exhaust duct60may be seated on the upper surface of the first step S1. The gas supply unit31may be provided in an inner space surrounded by the exhaust duct60.

The inside of the exhaust duct60may provide an exhaust space13. An exhaust hole14may be formed on one side (in more detail, on the side where the exhaust port3is located) of the exhaust duct60and in the upper body40of the reactor2. In more detail, the exhaust hole14may be formed in the sidewall50of the reactor. The exhaust hole14may be configured to connect the exhaust space13of the exhaust duct60with the exhaust port3.

The exhaust channel includes the exhaust space13and the exhaust hole14of the exhaust duct60, and may be formed continuously inside the exhaust duct60and the reactor sidewall50. The exhaust channel may extend from the reaction space R to the exhaust port3through the exhaust space13and the exhaust hole14, thereby connecting the reaction space R to the exhaust port3. The exhaust channel may be formed to surround the reaction space R, and thus, a reactive gas in the reaction space R may be relatively evenly exhausted.

The substrate support device70may include a susceptor body (not shown) supporting a substrate and a heater heating the substrate supported by the susceptor body. For loading/unloading of a substrate, the substrate support device70may be configured to be vertically movable by being connected to a driving motor (not shown) provided to one side of the substrate support device70. In more detail, during processing of the substrate, the substrate support device70, on which the substrate is mounted, may be raised to maintain a distance between the gas supply unit31and the substrate at a processable distance. When the substrate support device70is raised, the substrate support device70may form the reaction space R with the gas supply unit31and the upper body40. When the substrate process is completed, the substrate support device70may descend to a substrate unloading position and then unload the substrate.

The inner ring15may be seated on the first step S1formed below the upper body40. In more detail, the inner ring15may be seated on a lower surface of the first step S1. The inner ring15may generally have a circular ring shape, but is not limited thereto. The inner ring15may be fixed or movable with respect to the upper body40. The inner ring15may be a gas flow control ring (FCR). The inner ring15may control a pressure balance between the reaction space R and a lower space of the substrate support device70by adjusting the width of a gap between the first step S1of the upper body40and the substrate support device70, and may control an exhaust flow rate by adjusting an exhaust channel width between the inner ring15and a lower surface of the exhaust duct60.

According to further embodiments, the inner ring15may further include a stopper at the bottom. The stopper may prevent excessive movement of the inner ring15toward the reactor wall50. The stopper may be arranged on a lower surface of the inner ring15.

InFIG. 3, vertical distances A1and B1between the lower surface of the exhaust duct60and the inner ring15are constant throughout a circumference of the inner ring15. Therefore, the vertical distance A1between the lower surface of the exhaust duct60and the inner ring15at a first side X where the exhaust port3is located may be equal to the vertical distance B1between the lower surface of the exhaust duct60and the inner ring15at a second side Y opposite the first side X with respect to the center of the reactor2. That is, in the case of the reactor2ofFIG. 3, the vertical distance A1between the lower surface of the exhaust duct60and the inner ring15on the side closest to the exhaust port3may be equal to the vertical distance B1between the lower surface of the exhaust duct60and the inner ring15on the side farthest from the exhaust port3. In addition, a vertical distance between the lower surface of the exhaust duct60and the inner ring15may be the same as a vertical distance C between the substrate support device70and the gas supply unit31.

During a deposition/reactive gas supply operation, a process gas introduced through the gas inlet unit30may be supplied to the reaction space R and the substrate through the gas supply unit31. The process gas supplied on the substrate may undergo a chemical reaction with the substrate or a chemical reaction between gases, and then deposit a thin film or etch a thin film on the substrate.

Thereafter, in the reaction space R, a residual gas or un-reacted gas remaining after the chemical reaction with the substrate may be exhausted to the outside through an exhaust channel (i.e., the exhaust space13and the exhaust hole14), the exhaust port3and an exhaust pump (not shown) connected to the exhaust port3during an exhaust operation.

However, as described above, because the exhaust port3is located asymmetrically with respect to the center of the reactor2, an exhaust flow in the reactor2is asymmetric with respect to the center of the reactor2. In more detail, because the exhaust port3is located on the first side X of the reactor2, a gas exhaust rate at the side X close to the exhaust port3is greater than a gas exhaust rate at the side Y far from the exhaust port3. Due to the difference in the gas exhaust rates at the first side X and the second side Y, during the exhaust operation, the entire gas exhaust direction in the reaction space R may be a direction from the second side Y to the first side X. However, in a substrate processing process in which deposition/reactive gas supply, interruption, and exhaust are repeated, as shown inFIG. 3, due to the difference in the physical distance to the exhaust port3, gas may accumulate on the second side Y in the reaction space R compared to the first side X in the reaction space R, which may be a major cause of the asymmetry of a deposition profile of a thin film on the substrate (an asymmetric film profile). In particular, as in an atomic layer deposition method, the faster the cycle of gas supply, interruption, and exhaust, the worse this phenomenon.

Therefore, there is a need for a method of mitigating the accumulation of gas in the reaction space R on the side Y far from the exhaust port3.

FIG. 4is a view of a reactor according to embodiments of the present disclosure. Hereinafter, repeated descriptions of the embodiments will not be given herein.

Referring toFIG. 4, the vertical distance C between the substrate support device70and the gas supply unit31is the same throughout the substrate support device70. However, unlikeFIG. 3, a vertical distance between the inner ring15and a lower surface of the exhaust duct60may be different depending on the position. For example, an upper surface of the inner ring15ofFIG. 4may be configured to be higher on the second side Y than on the first side X. That is, the inner ring15may be configured to have a lower height on the first side X close to the exhaust port3. Accordingly, a vertical distance A2between the lower surface of the exhaust duct60and the inner ring15on the first side X may be longer than a vertical distance B2between the lower surface of the exhaust duct60and the inner ring15on the second side Y. For example, A2may be 1.5 mm and B2may be 1.0 mm.

Also, in an embodiment, the vertical distance A2between the lower surface of the exhaust duct60and the inner ring15on the first side X ofFIG. 4may be greater than the vertical distance A1between the lower surface of the exhaust duct60and the inner ring15on the first side X ofFIG. 3. That is, the vertical distance A2between the lower surface of the exhaust duct60and the inner ring15on the first side X may be greater than the vertical distance C between the substrate support device70and the gas supply unit31.

In a further embodiment, the vertical distance B2between the lower surface of the exhaust duct60and the inner ring15at the second side Y ofFIG. 4may be less than the vertical distance B1between the lower surface of the exhaust duct60and the inner ring15at the second side Y ofFIG. 3. That is, the vertical distance B2between the lower surface of the exhaust duct60and the inner ring15on the second side Y may be less than the vertical distance C between the substrate support device70and the gas supply unit31.

Because the inner ring15has such a structure, on the first side X close to the exhaust port3, the width of an inlet of an exhaust channel, where the reaction space R and the exhaust space13of the exhaust duct60meet, becomes wider. Accordingly, the gas exhaust rate at the first side X increases. On the other hand, the width of an inlet of the exhaust channel where the reaction space R and the exhaust space13of the exhaust duct60meet at the second side Y far from the exhaust port3becomes narrower. Accordingly, in the second side Y, a physical barrier (in this case, the inner ring15) on an exhaust flow path from the reaction space R to the exhaust space13becomes higher, so that the exhaust rate in a direction from the second side to the first side becomes faster.

Due to the difference in the gas exhaust rates at the first side X and the second side Y, during the exhaust operation, a gas exhaust direction in the reaction space R may be the direction from the second side Y to the first side X. However, as the gas exhaust rate at the first side X is greater than that in the embodiment ofFIG. 3, inFIG. 4, a gas exhaust rate from the second side Y to the first side X in the reaction space R may be greater than that ofFIG. 3. Accordingly, in the reaction space R, the accumulation of gas without being exhausted from the second side Y farthest from the exhaust port3may be alleviated, thereby improving the symmetry of a deposition profile of a thin film on a substrate.

In a variant embodiment, the vertical distance B2between the lower surface of the exhaust duct60and the inner ring15at the second side Y ofFIG. 4may be less than the vertical distance A2between the lower surface of the exhaust duct60and the inner ring15at the first side X, and may be greater than the vertical distance C between the substrate support device70and the gas supply unit31. Accordingly, the physical barrier (in this case, the inner ring15) on the exhaust flow path from the reaction space R to the exhaust space13at both the first side X and the second side Y becomes lower. Therefore, the gas exhaust rate may be increased in both the first side X and the second side Y.

In a further embodiment, the gas exhaust rate may be adjusted by adjusting at least one of the vertical distance A2between the exhaust duct60and the inner ring15on the first side X and the vertical distance B2between the exhaust duct60and the inner ring15at the second side Y. In a further embodiment, the uniformity of the thickness of a thin film deposited on a substrate or the symmetry of a deposition profile may be controlled by adjusting at least one of the vertical distance A2between the exhaust duct60and the inner ring15on the first side X and the vertical distance B2between the exhaust duct60and the inner ring15at the second side Y.

For example, in order to increase a gas exhaust flow rate near the exhaust port3, the thickness of the inner ring15on the first side X is made thin, so that the vertical distance A2between the lower surface of the exhaust duct60and the inner ring15on the first side X may be greater than the vertical distance C between the substrate support device70and the gas supply unit31. Thus, when a residual gas in the reaction space R on the substrate support device70is exhausted to the exhaust port3, the physical barrier (in this case, the inner ring15) on the exhaust channel may be lowered, and the residual gas in the reaction space R may be exhausted more quickly to the exhaust port3through the exhaust channel on the first side. Accordingly, the accumulation of gas without being exhausted from the second side Y may be alleviated and the exhaust rates from the second side Y to the first side X may be sped up and a thicker thin film may be prevented from being deposited on the second side Y compared to the first side X.

Also, in order to further accelerate an exhaust flow rate of the residual gas in the reaction space R to the exhaust port3, the thickness of the inner ring15on the second side Y is made thin, so that the vertical distance B2between the lower surface of the exhaust duct60and the inner ring15on the second side Y may be less than the vertical distance C between the substrate support device70and the gas supply unit31. As the physical barrier on the second side Y is higher than that on the first side X in the exhaust of gas to the exhaust duct60, during the same exhaust time, the amount of exhaust exhausted from the second side Y to the exhaust space13may decrease compared to the first side X, and the amount of gas remaining in the second side Y may further increase. Accordingly, by lowering the physical barrier of exhaust at the first side X close to the exhaust port3in the reaction space R, an exhaust pressure gradient may be formed in a direction from the second side Y to the first side X in the reaction space R. Accordingly, the exhaust of gas accumulated in the second side Y far from the exhaust port3is accelerated to be exhausted more quickly in a direction of the first side X, and the symmetry of a deposition profile of a thin film on the substrate may be improved.

However, on the contrary, the vertical distance B2between the lower surface of the exhaust duct60and the inner ring15at the second side Y may be less than the vertical distance A2between the lower surface of the exhaust duct60and the inner ring15at the first side X, and may be greater than the vertical distance C between the substrate support device70and the gas supply unit31. Accordingly, the gas exhaust rate may be increased in both the first side X and the second side Y, and the symmetry of a deposition profile of a thin film on the substrate may be improved.

In a further embodiment, as shown inFIG. 6, the upper surface of the inner ring15may be inclined from the second side Y toward the first side X to be higher at the second side Y than at the first side X. That is, the upper surface of the inner ring15may have a shape inclined toward the exhaust port3continuously or gradually. In other words, a distance between the exhaust duct60and the upper surface of the inner ring15may have a shape that gradually increases toward the exhaust port3or, the height (thickness) of the inner ring15gradually decreases toward the exhaust port3. The structure of the inner ring15is to control the exhaust rate by adjusting the distance between the inner ring15and the exhaust duct60. Accordingly, the gas exhaust flow rate may be adjusted by adjusting an inclination8of the upper surface of the inner ring15. In more detail, as the inclination8of the upper surface of the inner ring15increases, an exhaust pressure gradient in a direction from the second side Y to the first side X is strengthened and the exhaust flow rate of the residual gas in the reaction space R may increase. As the inclination8of the upper surface of the inner ring15decreases, the exhaust flow rate of the residual gas in the reaction space R in a direction from the second side Y to the first side X may decrease.

In the embodiments ofFIGS. 4 and 5, the exhaust channel may have a greater width in the first side X than in the second side Y. For example, the exhaust space13of the exhaust duct60may have a greater width as it approaches the exhaust port3and may increase the exhaust capacity. Thus, an exhaust flow in a direction of the exhaust port3may be strengthened, and the exhaust pressure gradient from the second side Y to the first side X in the reaction space R may be further strengthened. Accordingly, a phenomenon in which the residual gas accumulates on the second side Y may be reduced, and the symmetry of the thickness of a deposited film may be improved.

FIG. 5is a view of a reactor equipped with an outer ring according to other embodiments of the present disclosure. Hereinafter, repeated descriptions of the embodiments will not be given herein.

In order to further accelerate the exhaust flow rate of the residual gas in the reaction space R to the exhaust port3, an outer ring16may be mounted in addition to the reactor configuration ofFIG. 4.

In more detail, the first step S1toward the reaction space R may be formed below the upper body40. The first step S1may have an upper surface, a lower surface, and a side surface connecting the upper surface to the lower surface. The exhaust duct60may be seated on the upper surface of the first step S1, and the outer ring16may be seated on the lower surface of the first step S1.

In this case, the inner ring15may be seated on the outer ring16. In more detail, a second step S2toward the reaction space R may be formed on the outer ring16. The second step S2may have an upper surface, a lower surface, and a side surface connecting the upper surface to the lower surface. The inner ring15may be seated on the second step S2of the outer ring16, specifically on the lower surface of the second step S2.

The outer ring16may generally have a circular ring shape, but is not limited thereto. The outer ring16may be fixed to the upper body16. The outer ring16may be an FCR. The outer ring16may control an exhaust rate of gas exhausted from the reaction space R to the exhaust space13of the exhaust duct60by adjusting a vertical distance between the upper surface of the outer ring16and the exhaust duct60.

InFIG. 5, a vertical distance between the lower surface of the exhaust duct60and the outer ring16may be constant over the entire circumference of the outer ring16. Therefore, a vertical distance Dx between the lower surface of the exhaust duct60and the outer ring16at the first side X where the exhaust port3is located may be equal to a vertical distance Dy between the lower surface of the exhaust duct60and the outer ring16at the second side Y.

In order to lower the physical barrier (in this case, the inner ring15and the outer ring16) on the exhaust flow path from the reaction space R to the exhaust space13on the first side X, that is, in order to smoothly exhaust the residual gas in the reaction space R on the first side X into the exhaust space13of the exhaust duct60, the vertical distance Dx between the lower surface of the exhaust duct60and the outer ring16on the first side X may be longer than the vertical distance A2between the lower surface of the exhaust duct60and the inner ring15on the first side X. Thus, the width of an exhaust channel on the outer ring16on the first side X may be greater, and an exhaust flow to the exhaust port3may smoothly proceed.

In order to lower the physical barrier (in this case, the inner ring15and the outer ring16) on the exhaust flow path from the reaction space R to the exhaust space13on the second side Y, the vertical distance Dy between the lower surface of the exhaust duct60and the outer ring16on the second side Y may be longer than the vertical distance B2between the lower surface of the exhaust duct60and the inner ring15on the second side Y. Thus, the width of an exhaust channel on the outer ring16on the second side Y may be greater, and the exhaust flow to the exhaust port3may smoothly proceed.

As described with reference toFIGS. 4 and 5, according to embodiments of the present disclosure, by adjusting the vertical distance between the inner ring15and the lower surface of the exhaust duct60, an exhaust flow rate (from the second side Y to the first side X) in the reaction space R on the substrate support device70may be controlled. In addition, by adjusting the vertical distance between the outer ring16and the lower surface of the exhaust duct60, the respective exhaust flow rates from the upper space of the inner ring15to the exhaust space13on the first side X and the second side Y may be controlled. As such, according to embodiments of the present disclosure, by adjusting the respective distances between the inner ring15and the outer ring16surrounding the substrate support device70and the exhaust duct60, the exhaust flow rate may be controlled, and the symmetry of a thickness of a deposited film may be controlled. Further, it is possible to control the exhaust flow rate by maintaining the respective distances between the inner ring15and the outer ring16and the exhaust duct60asymmetrically. In spite of the asymmetry of the exhaust structure, a thin film having a symmetrical thickness profile may be deposited on the substrate. Unlike the prior art of changing the shape, number, or arrangement structure of exhaust holes14in order to improve a symmetric deposition profile of the deposited film, the disclosure may solve the problem that a thin film is asymmetrically deposited by only modifying the shape of the inner ring15. That is, using the disclosure, it is possible to solve a problem in that a thin film is symmetrically deposited with a minimum cost and time while minimizing structural changes of a substrate processing apparatus compared to the prior art.

FIGS. 7 and 8show results obtained by maintaining a distance between an inner ring and an exhaust duct asymmetrically.

FIGS. 7A and 7Bshow gas distribution or gas accumulation on substrates in the reactors ofFIGS. 3 and 4, respectively. That is,FIG. 7Ashows the distribution of a gas exhaust flow on the substrate support device70in the reactor2in which a vertical distance between the inner ring15and the exhaust duct60is uniform, andFIG. 7Bshows the distribution of a gas exhaust flow on the substrate support device70in the reactor2where the vertical distance between the inner ring15and the exhaust duct60becomes longer as it is closer to the exhaust port3.

In general, as in the case ofFIG. 7A, a vertical distance between an inner ring and an exhaust duct is uniform, so that a gas exhaust rate from the second side Y to the first side X in a reaction space is not fast and gas is relatively more accumulated on the second side Y than on the first side X. For an ALD process, gas supply and purge operations are repeated so that gas that has not been exhausted remains and accumulates in the reaction space located far from the exhaust port3during an exhaust time, that is, a limited purge time. This may be a major cause of the asymmetry of a deposition profile of a thin film on the substrate (an asymmetric film profile).

In the case ofFIG. 7B, a distance between the inner ring and the exhaust duct on the first side X close to the exhaust port3is greater, and thus, the gas exhaust rate at the first side X becomes faster. On the other hand, the distance between the inner ring and the exhaust duct at the second side Y far from the exhaust port3is less, and thus, an exhaust pressure gradient in a direction from the second side Y to the first side X is strengthened and the exhaust flow becomes faster. In the case ofFIG. 7B, the gas exhaust rate at the first side X is faster compared to the case ofFIG. 7A, and the gas exhaust rate from the second side Y to the first side X in the reaction space may be faster than that ofFIG. 7Aand the amount of remaining gas on the second side Y is almost the same as that on the first side X. Accordingly, despite a limited purge time, gas at the second side Y farthest from the exhaust port3in the reaction space does not accumulate, and rapid exhaust through the exhaust duct on the first side X may be possible. As such, by adjusting the distance between the inner ring and the exhaust duct, exhaust efficiency may be increased, and a phenomenon in which gas is accumulated on the second side Y may be alleviated.

FIG. 8shows the thickness and uniformity of SiO2thin films deposited in the reactor ofFIG. 3and the reactor ofFIG. 4.

In the case of the reactor ofFIG. 3, an inner ring having a flat top surface is used, and a distance between the inner ring and an exhaust duct is constant at 1.0 mm. In the case of the reactor ofFIG. 4, an inner ring with an inclined top surface is used, a distance between the inner ring and an exhaust duct on the side where the exhaust port3is located is 1.5 mm, and a distance between the inner ring and the exhaust duct on the opposite side of the exhaust port3is 1.0 mm, which are different from each other.

It can be seen that the uniformity of the SiO2thin film deposited in the reactor ofFIG. 3is 3.59%, and the SiO2thin film has an asymmetrical profile in which the thin film thickness becomes thicker as it is located farther from the exhaust port3.

However, it can be seen that the uniformity of the SiO2thin film deposited in the reactor ofFIG. 4is 2.95%, and the SiO2thin film profile is a concentric circle close to a circular shape. That is, in the use of the reactor ofFIG. 4(i.e., the reactor having an asymmetric exhaust structure), the problem that the farther away from the exhaust port3, the thicker the thin film is deposited on the substrate, and the closer to the exhaust port3, the thinner the thin film is deposited on the substrate can be reduced, and thin film uniformity/symmetry is improved compared to the reactor ofFIG. 3.

FIG. 9is a view of the substrate processing apparatus1according to an embodiment.

Referring toFIG. 9, the substrate processing apparatus1may include an outer chamber901providing an inner space902, at least one reactor2arranged in the inner space902, a deposition gas source903, a reactive gas source904, and an exhaust pump8. The reactor2may be the reactor2according to an embodiment described above with reference toFIGS. 4 and 5. In particular, the substrate processing apparatus1may increase productivity suitable for mass production by providing at least two or more reactors2. In the substrate processing apparatus1equipped with the plurality of reactors2, the exhaust port3of each reactor2is located on an outer wall of the reactor2and may be formed to pass through an outer wall of the substrate processing apparatus1. For example, as shown inFIG. 9, the exhaust port3on the reactor2may be configured to penetrate perpendicularly an edge surface where the two outer walls4and5of the substrate processing apparatus1intersect.

A substrate transfer arm (not shown) capable of rotation and elevation may be provided between four reactors2shown inFIG. 9, that is, in the center of the outer chamber901, thereby allowing substrate loading and unloading between the reactors2.

According toFIG. 9, at least one reactor2may be configured to receive a deposition gas from the deposition gas source903and to receive a reactive gas from the reactive gas source904. Further, the exhaust port3of the at least one reactor2may be connected to the exhaust pump8via an exhaust line at the side or at the bottom. That is, the reactor2may be configured such that an exhaust gas discharged through the exhaust port3of the at least one reactor2is exhausted through the exhaust line connected to the exhaust pump8. At this time, the at least one reactor2may share the exhaust line connecting the exhaust pump8to the reactor2, the deposition gas source903and the reactive gas source904with at least one other reactor. Thus, degrees of freedom may increase when designing the substrate processing apparatus1, and deposition processes may be efficiently managed. However, the method, performed by the at least one reactor2, of sharing the exhaust pump8, the deposition gas source903, and the reactive gas source904is not limited toFIG. 9, and the substrate processing apparatus1may use any other sharing method to improve productivity and efficiency of the substrate processing apparatus1

According to an embodiment, by providing a substrate processing apparatus having an asymmetric reactor structure, particularly an asymmetric exhaust structure, it is possible to improve the symmetry of the profile of a thin film deposited on a substrate.

According to an embodiment, by changing the shape of a gas flow control ring, the symmetry of the profile of a thin film deposited on a substrate may be improved.

According to an embodiment, the symmetry of a thin film profile may be improved with a minimum cost, time and change of the substrate processing apparatus, compared to the conventional one.