Thin film deposition apparatus and method of maintaining the same

A thin film deposition apparatus and a method of maintaining the same are disclosed. In one embodiment, a thin film deposition apparatus includes: a chamber including a removable chamber cover; one or more reactors housed in the chamber; a chamber cover lifting device connected to the chamber cover. The chamber cover lifting device is configured to move the chamber cover vertically between a lower position and an upper position. The apparatus further includes a level sensing device configured to detect whether the chamber cover is level, and a level maintaining device configured to adjust the chamber cover if the chamber cover is not level. This configuration maintains the chamber cover to be level as a condition for further vertical movement of the chamber cover.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean Patent Application No. 10-2008-0018234 filed in the Korean Intellectual Property Office on Feb. 28, 2008, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to a thin film deposition apparatus and a method of maintaining the same.

2. Description of the Related Art

In manufacturing semiconductor devices, various apparatuses and processes have been developed to provide a high quality thin film on a substrate. Several methods have been used to form a thin film, employing surface reaction of a semiconductor substrate. The methods include vacuum evaporation deposition, Molecular Beam Epitaxy (MBE), different variants of Chemical Vapor Deposition (CVD) (including low-pressure and organometallic CVD and plasma-enhanced CVD), and Atomic Layer Epitaxy (ALE). ALE was studied extensively for semiconductor deposition and electroluminescent display applications, and has been more recently referred to as Atomic Layer Deposition (ALD) for the deposition of a variety of materials.

Certain deposition apparatuses include one or more reactors housed in a chamber. Each of the reactors may include a substrate support on which a substrate is mounted.

It is sometimes necessary for a technician to have access to the interior of a chamber. Such a chamber is typically provided with a cover, which, when removed, allows access to components within a chamber. When such a cover is in the closed position, it provides a sealed environment within the chamber. Such a cover is typically manually dismounted and removed to gain access to the interior of the chamber.

SUMMARY

In one embodiment, a thin film deposition system includes: a chamber including a removable chamber cover; and a chamber cover lifting device connected to the chamber cover. The chamber cover lifting device is configured to move the chamber cover vertically between a lower position and an upper position. The apparatus also includes a level sensing device configured to detect whether the chamber cover is level.

In another embodiment, a deposition apparatus includes: a chamber body having a top face having an opening; a removable cover including a top surface; and a reflector mounted on the top surface of the removable cover. The reflector is formed of a material having a substantially higher reflectivity than the top surface of the removable cover.

In yet another embodiment, a method of maintaining a thin film deposition apparatus is provided. The method includes: vertically moving a removable chamber cover of a chamber in a deposition apparatus between a lower position and an upper position; detecting whether the chamber cover is level; and adjusting the chamber cover to be level if the chamber cover is not level.

<Description of Reference Numerals in the Drawings>10: chamber20: reactor cover30: substrate support40: chamber cover50: chamber cover lifting device60: level sensing device61: sensor62: reflector70: level maintaining device100: chamber frame

DETAILED DESCRIPTION OF THE EMBODIMENTS

The drawings are not to scale, but rather have dimensions exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element, such as a device or part, is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

As described above, certain deposition apparatuses include one or more reactors housed in a chamber. Examples of reactors include, but are not limited to, a chemical vapor deposition reactor or an atomic layer deposition reactor. Each of the reactors may include a substrate support on which a substrate is mounted during deposition.

In some embodiments, the chamber may include a removable chamber cover. The chamber cover may include reactor covers which are part of the one or more reactors. The chamber cover may be opened to repair or maintain parts inside the chamber.

Such deposition apparatuses may also include a plurality of air cylinders to support the chamber cover. The cylinders can be provided with compressed air to move the chamber cover upwardly. By stopping provision of compressed air to the cylinders, the chamber cover may be moved downward. In this manner, the cylinders may move the chamber cover between a lower position (where the chamber is closed) and an upper position (where the chamber is fully opened for maintenance).

While moving the chamber cover vertically, the chamber cover may not be level. When the chamber cover is not level, an excessive load may be applied to one of the cylinders. Thus, the cylinder may be bent or damaged, which may pose a danger to a technician. In addition, the reactors may be damaged due to incomplete contact between the reactor cover and the substrate support. Thus, it would be advantageous to provide such a deposition apparatus with a mechanism to maintain the chamber cover to be level while moving the chamber cover vertically.

FIG. 1is a cross-sectional view showing a thin film deposition system according to one embodiment. The illustrated system1includes a deposition apparatus110, a controller120, and an air control valve130.

The illustrated thin film deposition apparatus110includes a chamber frame100, a chamber10inside the chamber frame100, and a plurality of reactors15a,15binside the chamber10. The apparatus110also includes a removable chamber cover40, a chamber cover lifting device50, a level sensing device60, and a level maintaining device70. The level sensing device60and the level maintaining device70serve to maintain the chamber cover40in a level condition.

The chamber frame100may include a top portion100a, a bottom portion100b, and sidewalls100c,100dthat together define a space101to house the chamber10therein. In the illustrated embodiment, the chamber10is positioned generally at a vertically middle position inside the space101. In the context of this document, an upper portion of the space101above the chamber10may be referred to as an upper space101a, and a lower portion of the space101below the chamber10may be referred to as a lower space101b. The chamber frame100may include bars110that extend in a substantially horizontal direction and to help support the chamber10. The chamber frame100may also support the chamber cover lifting device50.

The chamber10includes a chamber body having a top face having an opening, and the removable chamber cover40. The chamber body may include a sidewall42, and a base plate45. The chamber cover40is vertically movable between an upper position and a lower position in the upper space101aof the chamber frame100. The chamber cover40seals and forms an upper portion of the chamber10when it is at the lower position. The sidewall42extends substantially vertically between the chamber cover40and the base plate45. The base plate45is positioned below the sidewall42of the chamber cover40. The base plate45may be fixed to the bars110of the chamber frame100.

The chamber10may include a plurality of reactors15a,15bdefined by the chamber cover40, the sidewall42, and the base plate45. Each of the reactors15a,15bmay include a reactor cover20and a substrate support30below the reactor cover20. Each of the reactors15a,15bincludes a reaction space therein.

The substrate support30may include a bottom portion that supports a substrate and a reactor wall extending from peripheral portions of the bottom portion. The bottom portion and the reactor wall may be integral with each other. The reactor cover20may have a bottom surface that is spaced apart from the bottom portion of the substrate support30. During a deposition process, the reactor wall of the substrate support30is in contact with the reactor cover20, thus forming the reaction space. In one embodiment, the reactor cover20may be attached to a lower surface of the chamber cover40. In such an embodiment, the reactor cover20may be moved vertically along with the chamber cover40.

The chamber cover lifting device50serves to move the chamber cover40vertically. In the illustrated embodiment, the chamber cover lifting device50includes a plurality of cylinders50a,50battached to bottom surfaces of first and second ends40a,40bof the chamber cover40. In the illustrated embodiment, a pair of cylinders50a,50bare provided. A skilled artisan will appreciate that the number of cylinders can vary widely, depending on the design of the deposition apparatus.

The cylinders50a,50bare together configured to vertically move the chamber cover40using compressed air. Each of the illustrated cylinders50a,50bincludes a fixed portion51and a reciprocating portion52. The reciprocating portion52is vertically movable by the operation of the compressed air. The reciprocating portion52is connected to the chamber cover40such that the chamber cover40can be moved vertically by the movement of the reciprocating portion52. Thus, the chamber cover40is moved upward while the reciprocating portions52move upward, and is moved downward while the reciprocating portions52move downward. In order to maintain the chamber cover40level when the chamber cover40is lifted up, the same amount of the compressed air should be simultaneously supplied to the two cylinders50aand50b.

The level sensing device60serves to detect whether or not the chamber cover40is level. The level sensing device60includes a sensor61that includes a light-emitting portion61aand a light-receiving portion61b. In the illustrated embodiment, the sensor61is fixed to the top portion100aof the chamber frame100. The light-emitting portion61aof the sensor61is configured to emit a light beam toward the chamber cover40. The light-receiving portion61bof the sensor61is configured to detect a light beam reflected by the chamber cover40. The light sensing device60is configured to provide a signal to the controller120if the light-receiving portion61bof the sensor61receives a light beam.

The level sensing device60also includes a reflector62on the chamber cover40. In the illustrated embodiment, the reflector62is positioned at the center of a top surface of the chamber cover40. The reflector62is configured to reflect the light beam emitted from the light-emitting portion of the sensor61. The reflector62may be formed of a specular material. In one embodiment, the reflector62may be formed of polycarbonate. In other embodiments, the reflector62may be formed of a metallic material having high reflectivity. The sensor61is positioned above the reflector62, and is spaced apart from the chamber cover40, and is fixed to the chamber frame100. In other embodiments, the sensor61can be fixed to other features in the clean room that are independent of the chamber10. In the illustrated embodiment, the top surface of the chamber cover40is formed of a non-reflective material or a material that has less reflectivity than the reflector62.

Referring toFIG. 2, the reflector62is mounted on the chamber cover40. The reflector62is positioned at the center of the chamber cover40in the illustrated embodiment. In one embodiment, the reflector62may have a square shape having a size of about 50 mm×about 50 mm. In other embodiments, the shape, size, and material of the reflector62may vary widely, depending on the reflectivity thereof and the sensitivity of the sensor61.

Referring again toFIG. 1, the controller120serves to control the operation of the apparatus. The controller120may include a general purpose computer including a central processing unit (CPU), a volatile and/or non-volatile memory device, a storage device, and a user interface (e.g., a monitor, a keyboard, a keypad, etc.). The controller120may control the operation of the valve130. In one embodiment, the controller120receives signals from the sensor61, and controls the operation of the valve130based on the signals.

In one embodiment, the controller120may also perform a chemical vapor deposition (CVD) process. In such an embodiment, at least two kinds of reaction materials may be simultaneously supplied into the reaction spaces of the reactors to grow thin films on substrates. In another embodiment, the controller may perform an atomic layer deposition (ALD) process. In such an embodiment, at least two kinds of reaction materials are sequentially and alternately supplied into the reaction spaces of the reactors to grow thin films on substrates. In other embodiments, a CVD or ALD process may be combined with plasma generation.

The valve130serves to control an amount of compressed air supplied to the cylinders50a,50b. A skilled artisan will appreciate that two or more valves may be used for the cylinders50a,50b. Examples of valves include, but are not limited to, a solenoid valve and a pneumatic valve.

Referring still toFIG. 1, during operation, the sensor61emits a light beam A toward the chamber cover40. When the chamber cover40is level, a light beam B reflected from the reflector62travels along the same path as the light beam A, but in the opposite direction from that of the light beam A, and reaches the sensor61. Thus, the light-receiving portion of the sensor61can detect the light beam B. If, however, the chamber cover40is not level, the light beam B reflected from the reflector62travels at an angle with the path of the light A, and does not reach the sensor61. Thus, the sensor61can determine whether or not the chamber cover40is level.

The level maintaining device70serves to maintain the chamber cover40level. The illustrated level maintaining device70includes a plurality of springs including a first spring71and a second spring72. In other embodiments, the level maintaining device70may include any suitable device that can provide a self-restoring force to the chamber cover40. In the illustrated embodiment, only two springs are shown. In other embodiments, a different number of springs (for example, 3, 4, 5, 6, 7, 8, 9, 10, or greater) may be used, depending on the number of cylinders.

In the illustrated embodiment, the springs71,72are extension springs. The extension springs may be helical springs designed to store energy and resist a pulling force applied along the axis of the spring. In another embodiment, the springs71,71may be compression springs. In other embodiments, any other suitable types of springs may be adapted for the use as the springs71,72. The springs71,72have the same configuration as each others such that they exert the same amount of restoring force to opposite ends40a,40bof the chamber cover40.

Each of the springs71and72surrounds a respective one of the reciprocating portions52of the cylinders50a,50b. The springs71,72are located between the chamber cover40and the fixed portions51of the cylinders50a,50b. One end of each of the springs71,72is fixed to the chamber cover40and the other end is fixed to one of the fixed portions51of the cylinders50a,50b. The springs71and72are stretched when the chamber cover40is lifted up to the upper position by the reciprocating portions52of the cylinders. The springs71,72are compressed when the chamber cover40is moved down to the lower position by the reciprocating portions52of the cylinders50a,50b.

In the illustrated embodiment where the springs71,72are extension springs, the springs71,72resist a pulling force applied along the axis of the springs71,72. Thus, when the springs71,72are in an extended state (for example, when the chamber cover40is at the upper position or between the upper and lower positions, seeFIGS. 3 and 4), they tend to return to an unextended state (for example, when the chamber cover40is at the lower position, seeFIG. 1). When the force is removed, the springs71,72provide a downward restoring force to the chamber cover40, and move the chamber cover40toward the lower position.

The springs71,72each exert substantially the same restoring force to the chamber cover40. When the springs71,72are extended to the same extent, the springs71,72provide substantially the same amount of downward pulling force to the ends40a,40bof the chamber cover40. Thus, it is possible to maintain the chamber cover40to be level.

Referring toFIG. 3, the operation of the level sensing device and the level maintaining device will be described below.FIG. 3shows the thin film deposition apparatus ofFIG. 1when the chamber cover is inclined. The level sensing device60emits a light beam A from the sensor61to the reflector62when the chamber cover40is lifted using the first cylinder50aand the second cylinder50b. If the chamber cover40is inclined, the reflector62is also inclined. Thus, a light beam B reflected from the reflector62does not reach the sensor61. In that instance, the level sensing device60cannot detect the light beam B, and the controller120(FIG. 1) determines that the chamber cover40is not level.

In one embodiment, the level sensing device60can have dimensions such that it can detect the reflected light beam B from the reflector62when an angle α between the light beam A (which is emitted from the sensor61) and the light beam B is within about 3 degrees, or optionally within about 2 degrees. The angle α may depend on the vertical distance between the sensor61and the reflector62. For example, the angle α may be about 2 to about 3 degrees when the chamber cover40is at the upper position while the angle α may be less than about 1 degree when the chamber cover40is at the lower position.

When the angle α is within a selected limit, the chamber cover40can be indicated as being “substantially level” in the context of this document. A skilled artisan will appreciate that the angle α can vary widely, depending on the type of the light sensor61. If the sensor61detects the light beam B, it can provide the controller120with a signal indicating that the chamber cover40is level.

In the apparatus ofFIG. 3, the first end40aof the chamber cover40is lower than the second end40bof the chamber cover40. The first end40aand the second end40bare opposite ends of the chamber cover40. When the level sensing device60determines that the chamber cover40is not level, the operations of the first and the second cylinders50a,50bare stopped, thereby stopping the vertical movement of the chamber cover40. In one embodiment, this can be achieved by closing the valve130that controls air supply to the first and second cylinders50a,50b. In the illustrated embodiment where the first and second springs71,72are extension springs, the second spring72is more extended than the first spring71. Thus, the second spring72exerts a greater amount of downward restoring force to the chamber cover40than the first spring71. Thus, by providing a different amount of force downwardly, the springs71,72return the chamber cover40to a leveled state. A skilled artisan will appreciate that other types of springs can also provide leveling function similar to that of the extension springs.

When the chamber cover40becomes level, as detected by the level sensing device60, the air control valve130is re-opened to supply the air to the cylinders50a,50b. Determining that the chamber cover40is level, and any adjustments needed by the level maintaining device70in order to achieve that level condition, is thus a condition that needs to be met for further vertical movement of the chamber cover40. The chamber cover40is then allowed to continue to move upward.

FIG. 4is a diagram illustrating operation of the level sensing device60and the level maintaining device70when the chamber cover is level. As shown inFIG. 4, when the chamber cover40is lifted using the first cylinder50aand the second cylinder50b, the level sensing device60emits a light beam from the sensor61to the reflector62. When a light beam A emitted from the sensor61is reflected by the reflector62, and a reflected light beam B reaches the sensor61, it is determined that the chamber cover40is level. Thus, the chamber cover40continues to be lifted. Since the first spring71and the second spring72exert the same amount of restoring force to the chamber cover40, they can prevent the chamber cover40from being inclined.

Next, a method of maintaining the thin film deposition apparatus with the use of the level sensing device60and the level maintaining device70will be described below. First, as shown inFIG. 4, the chamber cover40covering the chamber10is lifted up using the chamber cover lifting device50.

Then, while the chamber cover40is lifted, the level sensing device60determines whether the chamber cover40is level. If the level sensing device60determines that the chamber cover40is level, the chamber cover lifting device50aand50bcontinues to move the chamber cover40to the upper position. When the chamber cover40is at the upper position, a chamber maintenance process can be performed.

However, as shown inFIG. 3, when the level sensing device60determines that the chamber cover40is not level, the operations of the chamber cover lifting device50are stopped. Then, the chamber cover40is adjusted to be level by the level maintaining device70connected to the chamber cover40. When the chamber cover40is restored to be level, the operation of the chamber cover lifting device50is resumed to lift the chamber cover40.