Multi-mode thin film deposition apparatus and method of depositing a thin film

A multi-mode thin film deposition apparatus including a reaction chamber, a carrying seat, a showerhead, an inert gas supplying source, a first gas inflow system and a second gas inflow system is provided. The carrying seat is disposed in the reaction chamber. The showerhead has a gas mixing room and gas holes disposed at a side of the gas mixing room. The gas mixing room is connected to the reaction chamber through the plurality of gas holes which faces the carrying seat. The first gas inflow system is connected to the reaction chamber and supplies a first process gas during a first thin film deposition process mode. The inert gas supplying source is connected to the gas mixing room for supplying an inert gas. The second gas inflow system is connected to the gas mixing room to supply a second process gas during a second thin film deposition process mode.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 102143232, filed on Nov. 27, 2013. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

The disclosure relates to a multi-mode thin film deposition apparatus and a method of depositing a thin film.

BACKGROUND

Organic semiconductor material and low power function electrode of an organic light-emitting diode (OLED) are degraded easily by oxygen and mist. In the process of commercialization of OLED, there are always challenges to increase the stability and the useful time of the elements of OLED by effective packaging technology. The conventional packaging method can not meet the requirement cause of the high cost and without flexibility. It becomes a trend to use atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) technology to produce a flexible barrier film.

The rate of ALD process depositing high compactness and low defect inorganic thin film such as aluminum oxide (Al2O3) is slow. It may take 200˜300 minutes to reach the required packaging thickness about 2030 nm of an OLED by the ALD process. Without decreasing the cost effectively, the adoption in the market is low. Although the deposition rate of PECVD process is faster, plasma induced damage may occur in the elements of an OLED easily. With the combination of the advantages of these two deposition processes, dozens of atomic layers are deposited about 20 minutes by the ALD process to form a non-defect thin film (i.e. aluminum oxide layer) with the thickness about 2 nm, and a thicker Silicon Nitride (SiNx) layer is deposited by the PECVD process to against the aluminum oxide layer from hydrolysis in the air. Because of the non-defect thin film produced by the ALD process is compact, the non-defect thin film may protect the elements of the OLED from the influence of plasma induced damage during the PECVD process. It may substantially decrease the process time from 4-5 hours to 0.5 hour forming the barrier film.

However, in recent technology, the deposition steps during the ALD and the PECVD process are performed in two different chambers individually. It does not only increase the costs, but also expose the elements of the unfinished packaging OLED in the environment during the transfer process and cause low quality of the barrier film. Besides, the ALD process is entirely different from the PECVD process. The PECVD process must uniform the mix process gas via a showerhead, and produce plasma to ionize the process gas as a coating precursor reactant. For the reason, the showerhead is designed having 1˜3 layers of gas diffusion space as buffer regions, so as to carry out the purpose of outputting gas uniformly. However, the ALD process emphasizes how to make the coating precursor reactant distribute and adhere on the substrate saturantly in the lowest cycle time. Hence, if the ALD process is performed via the showerhead of the PECVD process, for the purpose of saturate distribution, the process gas have to be filled in the showerhead and the entire chamber. Thus, the cycle time and the gas volume of use will increase.

SUMMARY

An exemplary embodiment of the disclosure provides a multi-mode thin film deposition apparatus including a reaction chamber, a carrying seat, a showerhead, an inert gas supplying source, a first gas inflow system and a second gas inflow system. The reaction chamber has a first opening and a second opening which penetrate through the reaction chamber and have the same axial direction. The carrying seat is disposed in the reaction chamber and suitable to carry a substrate. The showerhead has a gas mixing room and a plurality of gas holes. The plurality of gas holes is disposed at a side of the reaction chamber and faces to the carrying seat. The gas mixing room is connected to the reaction chamber through the plurality of gas holes. The first gas inflow system is connected to the first opening and suitable to supply a first process gas during a first thin film deposition process mode. The inert gas supplying source is connected to the gas mixing room of the showerhead and suitable to supply an inert gas which is non-reactive to the first process gas. The second gas inflow system is connected to the gas mixing room of the showerhead and suitable to supply a second process gas during a second thin film deposition process mode.

An exemplary embodiment of the disclosure also provides a method of depositing a thin film by using the foregoing multi-mode thin film deposition apparatus. The method includes providing a substrate and deposing the substrate on the carrying seat. Then, the first thin film deposition process mode is performed. During the first thin film deposition process, the first gas inflow system and the inert gas supplying source are opened synchronously. The first process gas is supplied by the first gas inflow system through the first opening to the reaction chamber, and an inert gas enters the reaction chamber via the plurality of gas holes of the showerhead at the same time. By controlling the inflow of the inert gas, the pressure of the gas mixing room and the gas holes is higher than the pressure of the reaction chamber. The inert gas outputting from the showerhead makes the first process gas attach to the substrate and forms a first thin film on the substrate. After that, the first gas inflow system and the inert gas supplying source are closed. Then, the second thin film deposition process mode is performed. During the second thin film deposition process, the second gas inflow system is opened. The second process gas enters the reaction chamber through the plurality of gas holes of the showerhead and forms a second thin film on the substrate.

An exemplary embodiment of the disclosure provides another method of depositing a thin film including providing a substrate which is disposed in a reaction chamber. Then, an ALD process mode is performed and a first process gas including at least two different precursor reactant gases is supplied. The at least two precursor reactant gases enter the reaction chamber through a first opening, respectively. When the at least two precursor reactant gases enter the reaction chamber, an inert gas is supplied by a showerhead at the same time. The inert gas outputting by the showerhead makes the first process gas attach to the substrate and forms a first thin film on the substrate. Subsequently, a PECVD process mode is performed and a second process gas is performed through the showerhead to form a second thin film on the substrate. In addition, the ALD process and the PECVD process are performed in the same reaction chamber.

In order to make the aforementioned and other features of the disclosure comprehensible, several exemplary embodiments accompanied with figures are described in detail below.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

The disclosure provides a multi-mode thin film deposition apparatus which is suitable to perform various modes of thin film deposition process on a substrate in a single chamber.

FIG. 1is a structural schematic diagram of a multi-mode thin film deposition apparatus according to an embodiment of the disclosure. Referring toFIG. 1, the multi-mode thin film deposition apparatus1includes a reaction chamber10, a carrying seat20, a first gas inflow system30, a showerhead40, an inert gas supplying source50, and a second gas inflow system60. The reaction chamber10has a first opening12and a second opening14which transversely penetrate through the reaction chamber10and have the same axial direction. The carrying seat20is disposed in the reaction chamber10and suitable to carry a substrate22. In one embodiment of the disclosure, the multi-mode thin film deposition apparatus1further includes an elevating mechanism24connected to the carrying seat20. The elevating mechanism24is suitable to adjust the position of the carrying seat20. The first gas inflow system30is connected to the first opening12and is suitable to supply a first process gas PS1 during a first thin film deposition process mode. In addition, the disposed direction of the carrying seat20is parallel to the axial direction of the first opening12and the second opening14so that the first process gas PS1 enters from the first opening12and flows to the second opening14along the disposed direction of the carrying seat20. The showerhead40has a gas mixing room42and a plurality of gas holes44. The plurality of gas holes44is disposed at a side of the reaction chamber40and faces to the carrying seat20. The gas mixing room42is connected to the reaction chamber40through the plurality of gas holes44. The inert gas supplying source50is connected to the gas mixing room42of the showerhead40and is suitable to supply an inert gas IG. Besides, the inert gas IG means a gas which is non-reactive to the first process gas PS1. In an embodiment of the disclosure, the inert gas IG is listed on Group VIIIA such as argon (Ar) of the periodic table, but it is not limited herein. The second gas inflow system60is connected to the gas mixing room42of the showerhead40and is suitable to supply a second process gas PS2 during a second thin film deposition process mode.

In the embodiment of the disclosure, the first gas inflow system30further includes an air-extracting system70connected to the second opening14of the reaction chamber10. The gas-extracting system70may be a pump, but is not limited herein. The gas-extracting system70offers a function of gas-extracting during modes transforming or mode performing. The gas and the reactant produced during the processes in the reaction chamber10and the gas mixing room42are extracted by the gas-extracting system70. This will prevent the multi-mode thin film deposition apparatus1from causing pollution.

In detail, the first gas inflow system30includes a first gas supplying source32and a second gas supplying source34. The first gas supplying source32is connected to the first opening12of the reaction chamber10via a first gas supplying tube36and the second gas supplying source34is connected to the first opening12of the reaction chamber10via a second gas supplying tube38. In one embodiment of the disclosure, the first thin film deposition process mode is an atomic layer deposition (ALD) process mode. In the first thin film deposition process mode, the first process gas PS1 includes a first precursor reactant gas PC1 and a second precursor reactant gas PC2 supplied from the first gas supplying source32and the second gas supplying source34, respectively.

Besides, in another embodiment of the disclosure, the first thin film deposition process mode is a plasma-enhanced atomic layer deposition (PEALD) process mode. The multi-mode thin film deposition apparatus1further includes a second voltage supplying source82connected to the first gas inflow system30. When performing the PEALD process, the first process gas PS1 is applied a bias voltage by the second voltage supplying source82and produces plasma. Further, the second voltage supplying source82applies the bias voltage to one of the first precursor reactant gas PC1 and the second precursor reactant gas PC2 of the first process gas PS1 and one of the precursor reactant gases (i.e. PC1 and PC2) produces single wafer plasma to form a thin film on the substrate22.

On the other hand, the multi-mode thin film deposition apparatus1further includes a first voltage supplying source80connected to the showerhead40. In the embodiment of the disclosure, the second thin film deposition process mode is a plasma-enhanced chemical vapor deposition (PECVD) process mode. During the PECVD process, the first voltage supplying source80supplies a bias voltage to the second process gas PS2 which enters from the second gas inflow system60to the showerhead40and produces the plasma.

In addition, the multi-mode thin film deposition apparatus1further includes a flow control unit90which is connected to the first gas inflow system30, the second gas inflow system60and the inert gas supplying source50, respectively. During the different thin film deposition process modes, the flow control unit90controls the flow of the first process gas PS1, the second process gas PS2 and the inert gas IG, respectively.

The operation of the multi-mode thin film deposition apparatus during different thin film deposition process modes are describe below by referringFIG. 2andFIG. 3.

FIG. 2is a schematic diagram of the flow of a process gas when the multi-mode thin film deposition apparatus performs a first thin film deposition process mode according to an embodiment of the disclosure. Please refer toFIG. 2, the substrate22is provided which is disposed on the carrying seat20in the reaction chamber10at first. Then, the first thin film deposition process mode is performed. During the first thin film deposition process, the first gas inflow system30and the inert gas supplying source50are opened synchronously. The first process gas PS1 is supplied by the first gas inflow system30through the first opening12to the reaction chamber10, and an inert gas IG enters the reaction chamber10via the plurality of gas holes44of the showerhead40at the same time. At this time, the inflow of the inert gas IG flows from the inert gas supplying source50via the adjustment of the flow control unit90, so that the pressure of the gas mixing room42of the showerhead40and the plurality of gas holes44is higher than the pressure of the reaction chamber10. In detail, when the first process gas PS1 enters to the reaction chamber10through the first opening12and outflows the second opening14along the flow direction, the reaction chamber10and the gas mixing room42should be filled with the first process gas PS1 at first. Because of the inert gas IG spouting out from the showerhead40, the difference of the pressure leads the first process gas PS1 unable to enter the gas mixing room42through the plurality of gas holes44. Thus, deposition of the first process gas PS1 on the plurality of gas holes44will be avoided so as to prevent the gas holes44from being blocked. Furthermore, without filling with the inert gas IG in the gas mixing room42of the showerhead40and the plurality of gas holes44, when performing the first thin film deposition process, the first process gas PS1 is essential to fill with the entire reaction chamber10, the gas mixing room42of the showerhead40, and the plurality of gas holes44. This may lead to unnecessary waste of the first process gas PS1. In detail, because the inert gas IG non-reactive to the first process gas PS1 enters the reaction chamber10, the first process gas PS1 in the reaction chamber10flows to the second opening14along a direction as shown inFIG. 2. In this embodiment of the disclosure, the axial direction of the first opening12and the second opening14are the same, and the first opening12and the second opening14transversely penetrate through the reaction chamber10. The plurality of gas holes44faces the carrying seat20. Thus, the configuration relationships leads the first process gas PS1 attached to the substrate22via the inert gas IG outputted from the showerhead40during the process that the first process gas PS1 enters from the first opening12and flows to the second opening14.

In the embodiment of the disclosure, the first thin film deposition process mode is an ALD process mode. The first process gas PS1 includes at least two different precursor reactant gases such as the first precursor reactant gas PC1 and the second precursor reactant gas PC2 that are mentioned before. The first precursor reactant gas PC1 and the second precursor reactant gas PC2 are supplied from the first gas supplying source32and the second gas supplying source34, respectively, and enter the reaction chamber10at time intervals through the first opening12. In detail, during the ALD process mode, the first precursor reactant gas PC1 enters the reaction chamber10at first, and the showerhead40offers the inert gas IG at the same time. The flow control unit90controls the flow of the first precursor reactant gas PC1 and the inert gas IG so as to lead the pressure of the gas mixing room42higher than the pressure of the reaction chamber10. In one embodiment, the ratio of the flow rate of the first precursor reactant gas PC1 to the flow rate of the inert gas IG ranges of 2/3 to 5/4. However, the ratio of the flow rate of the first precursor reactant gas PC1 to the flow rate of the inert gas IG in the reaction chamber10is not limited herein. As long as the flow of the first precursor reactant gas PC1 and the inert gas IG are controlled by the flow control unit90and the first precursor reactant gas PC1 is leaded to reach saturated distribution on the substrate22, the ALD process mode is performed. Then, the first precursor reactant gas PC1 and the inert gas IG are extracted by the gas-extracting system70through the second opening14. After a time interval, the second precursor reactant gas PC2 is input and the inert gas IG is injected at the same time. The process is the same with the first precursor reactant gas PC1, it repeated no more herein. When the second precursor reactant gas PC2 reaches the substrate22, a first thin film is produced after the reaction. The first gas inflow system30and the inert gas supplying source50are then closed to finish the ALD process mode. In one embodiment of the disclosure, the gas-extracting system70is opened to adjust the pressure of the reaction chamber10during all the ALD process mode.

FIG. 3is a schematic diagram of the flow of a process gas when the multi-mode thin film deposition apparatus performs a second thin film deposition process mode according to an embodiment of the disclosure. Please refer toFIG. 3, when performing the second thin film deposition process mode, the second gas inflow system60is opened and the second process gas PS2 enters the gas mixing room42of the showerhead40. After mixing amply in the gas mixing room42, the second process gas PS2 enters the reaction chamber10through the plurality of gas holes44. In the embodiment of the disclosure, the second thin film deposition process mode is a plasma-enhanced chemical vapor deposition (PECVD) process mode. When the second process gas PS2 supplied by the showerhead40enters the reaction chamber10, the first voltage supplying source80is turned on and offers a radio frequency bias voltage to the second process gas PS2. Plasma is produced and then a second thin film is formed on the substrate22.

In addition, during the first thin film deposition process mode, because the inert gas IG is injected into the reaction chamber10, the first thin film deposition process mode is performed with less first process gas PS1. Besides, the injection of the inert gas IG may also prevent the plurality of gas holes44of the showerhead40from being blocked by the first process gas PS1 and maintain the quality of the operation during the second thin film deposition process mode. Thus, the first thin film deposition process mode (ALD process mode) and the second thin film deposition process mode (PECVD process mode) will be performed in the same reaction chamber.

Furthermore, during the ALD process mode, the first voltage supplying source80is turned off. However, when the multi-mode thin film deposition apparatus1further includes a second voltage supplying source82connected to the first gas inflow system30, a plasma-enhanced atomic layer deposition (PEALD) process will also be performed. During the PEALD process, the second voltage supplying source82is turned on and one of the first precursor reactant gas PC1 and the second precursor reactant gas PC2 forms a single wafer plasma. Then, a third thin film is formed on the substrate22.

In summary, in the embodiments of the disclosure, during the first thin film deposition process mode, by controlling the flow rate of the first process gas and the inert gas in the reaction chamber, the first process gas is reacted and deposited on the substrate. Besides, because of the injection of the inert gas during the first thin film deposition process mode, it will prevent the plurality of gas holes from being blocked. Furthermore, it will also be prevented that the entire showerhead and the gas chamber are filled with the first process and the waste of the first process gas is thus prevented. For this reason, in the embodiments of the disclosure, by using the multi-mode thin film deposition apparatus, the multi-mode thin film deposition processes will be performed in the same reaction chamber without transferring the substrate to different reaction chamber during different mode thin film deposition processes. It may save the consumed time of the transferring process of the substrate.