Patent Publication Number: US-2017369994-A1

Title: Apparatus for processing a wafer and method of depositing a thin film using the same

Description:
CROSS-REFERENCES TO RELATED APPLICATION 
     The present application claims priority under 35 U.S.C. §119(a) to Korean application number 10-2016-0080809, filed on Jun. 28, 2016, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     Various embodiments generally relate to an apparatus for processing a wafer and a method of depositing a thin film using the same, more particularly to an atomic layer deposition apparatus and a method of deposition a thin film using the apparatus. 
     2. Related Art 
     Generally, in order to deposit a thin film on a wafer or a glass substrate, a physical vapor deposition (PVD) apparatus, a chemical vapor deposition (CVD) apparatus, etc., may be used. 
     The CVD apparatus may include a substrate support, an edge ring and a purge ring. The edge ring and the purge ring may be arranged at an edge portion of the substrate support. The edge ring and the purge ring may include a purge gas nozzle configured to prevent a layer from being deposited on edge portions of an upper surface and a bottom surface of the wafer. The edge ring may be configured to inject a purge gas to the edge portion of the upper surface of the wafer. The purge ring may be configured to inject the purge gas to the edge portion of the bottom surface of the wafer. 
     Recently, as a semiconductor device may be highly integrated, a design rule may become remarkably reduced so that a minute pattern the thin film may be required. In order to meet the requirement, an atomic layer deposition (ALD) apparatus may be used. Further, in order to improve a yield of the semiconductor device, the edge portion of the wafer may be used for a device region. 
     However, because the edge ring may be configured to inject the purge gas to the edge portion of the upper surface of the wafer, improving the yield of the semiconductor device may be limited due to the edge ring. 
     SUMMARY 
     In an embodiment, an apparatus for processing a substrate may include a chamber, a substrate support, a showerhead structure and a purge ring structure. The chamber may have a sealed process region. The substrate support may be arranged at a lower region in the chamber to support the substrate. The substrate support may include a gas passageway through which a deposition-preventing gas may be exhausted. The deposition-preventing gas may be supplied to a sidewall of the substrate support by the gas passageway. The showerhead structure may be arranged at an upper region in the chamber to supply a source gas and a reaction gas to the substrate support. The purge ring structure may be arranged at an edge portion of the substrate support to inject the deposition-preventing gas, which may be supplied from an inner portion of the substrate support, to an edge portion of an upper surface of the substrate. The purge ring structure may include a purge ring and a plurality of bosses. The purge ring may be configured to surround the substrate. The bosses may be protruded from an inner surface of the purge ring in a radius direction of the substrate to form a gap between the inner surface of the purge ring and the edge portion of the substrate. The deposition-preventing gas may be supplied to the upper surface of the substrate through the gap. 
     For example, each of the bosses has a thickness of about 0.1 mm to about 1.5 mm toward a center point of the purge ring. Further, the bosses are at least three for providing the gap between the edge portion of the substrate and the inner surface of the purge ring. Thus, the edge portion of the substrate is not contacted with the inner surface of the purge ring by the gap. 
     In an embodiment, in a method of depositing a thin film, a substrate may be placed on a substrate support in a chamber. The substrate support may be upwardly moved to a process region in the chamber. The thin film may be deposited on the substrate in the process region. The substrate support may be downwardly moved. The substrate may be unloaded from the chamber. Depositing the thin film may include supplying a source gas to the substrate, supplying a reaction gas to the substrate, and injecting a deposition-preventing gas to an edge portion of an upper surface of the substrate during supplying the reaction gas. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating an apparatus for processing a substrate in accordance with example embodiments; 
         FIG. 2  is an enlarged cross-sectional view illustrating a purge ring structure in accordance with example embodiments; 
         FIG. 3  is a perspective view illustrating a purge ring structure in accordance with example embodiments; 
         FIG. 4  is a plan view illustrating a purge ring structure in accordance with example embodiments; 
         FIG. 5  is a timing chart illustrating a method of depositing a thin film by an ALD process in accordance with example embodiments; and 
         FIG. 6  is a timing chart illustrating a method of depositing a thin film by a CVD process in accordance with example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, example embodiments will be described below with reference to the accompanying drawings through various examples of embodiments. 
       FIG. 1  is a cross-sectional view illustrating an apparatus for processing a substrate in accordance with example embodiments. 
     Referring to  FIG. 1 , an apparatus  100  for processing a substrate W may include an ALD apparatus. The ALD apparatus  100  may include a vacuum chamber  110  configured to define a process region  110   a . A substrate support  120  may be arranged in the vacuum chamber  110 . 
     A showerhead structure  130  may be installed at a top surface of the process region  110   a . The showerhead structure  130  may be configured to supply a process gas including a source gas and a reaction gas into the process region  110   a . The showerhead structure  130  may include a plurality of injecting holes configured to inject the process gas to the substrate W. 
     The substrate support  120  may include a stage  121  and a hollow support  122 . The stage  121  may be configured to receive the substrate W. The hollow support  122  may be installed on a bottom surface of the process region  110   a  to support the stage  121 . 
     A main gas passageway  140   a  may be formed in the substrate support  120 . The main gas passageway  140   a  may be connected with a deposition-preventing gas source. Thus, a deposition-preventing gas may be supplied through the main gas passageway  140   a.    
     A purge ring structure  150  may be arranged at an edge portion of an upper surface of the substrate support  120  to define a sub-gas passageway  140   b . The sub-gas passageway  140   b  may be connected to the main gas passageway  140   a  to supply the deposition-preventing gas supplied from the sub-gas passageway  140   b  to a bottom surface of the substrate W and a sidewall of the substrate support  120 . Particularly, in order to provide the edge portion of the bottom surface of the substrate W with the deposition-preventing gas, the purge ring structure  150  may be positioned at the edge portion of the substrate support  120 . 
       FIG. 2  is an enlarged cross-sectional view illustrating a purge ring structure in accordance with example embodiments, FIG. is a perspective view illustrating a purge ring structure in accordance with example embodiments, and  FIG. 4  is a plan view illustrating a purge ring structure in accordance with example embodiments. 
     Referring to  FIGS. 2 to 4 , the purge ring structure  150  may include an annular purge ring  152  and a plurality of bosses  155 . The bosses  155  may be formed on an inner surface of the purge ring  152 . In example embodiments, the bosses  155  may be three. 
     The purge ring  152  may be installed at an edge portion of the stage  121  of the substrate support  120  to surround the substrate W. 
     The bosses  155  may be protruded from the inner surface of the purge ring  152  in a radius direction of the substrate W. The bosses  155  may function as to adjust a gap between the substrate W and the purge ring  152 . Thus, the bosses  155  may form a gap  160  between the inner surface of the purge ring  152  and the edge portion of the substrate W. Therefore, the deposition-preventing gas and an additional reaction gas may be uniformly supplied to the upper surface of the substrate W through the gap  160 . In order to uniformly distribute the gas on the edge portion of the substrate W, the bosses  155  may be spaced apart from each other by a substantially same interval. Each of the bosses  155  may have a thickness of about 0.1 mm to about 1.5 mm toward a center point of the purge ring  152 . The inner surface of the purge ring  152  may not make contact with the edge portion of the substrate W due to the bosses  155  to define the gap  160 . 
     An inclined portion  157  may be formed between an upper surface of the purge ring  152  and an upper surface of the boss  155 . Particularly, the inclined portion  157  may be formed at an upper portion of the inner surface of the purge ring  152 . The inclined portion  157  may function as to align the substrate W with the substrate support  120 . 
     According to example embodiments, the purge ring structure  150  may function as to uniformly inject the deposition-preventing gas and the additional reaction gas on the edge portions of the upper surface and the bottom surface of the substrate W so that a deposited thickness of a thin film, for example, a metal layer may be accurately controlled. The gaps  160  may have uniform size considered as the thickness uniformity of the thin film. 
     The apparatus for processing the substrate may include the purge ring structure configured to supply the deposition-preventing gas and the additional reaction gas through the gap between the purge ring and the substrate with supplying of the gas to the bottom surface of the substrate without an edge ring. Therefore, the edge portion of the substrate may not be covered with a structure. Further, the gases may be effectively supplied to the upper surface and the bottom surface of the substrate so that the edge portion of the substrate may be used for a device region. Furthermore, the thin film deposited on the substrate may have uniform thickness. As a result, a yield of the semiconductor device may be remarkably improved. 
     The apparatus for processing the substrate may be operated as follows. 
     The substrate W may be loaded into the chamber  110  through an entrance D 1 . The substrate W may be placed on the stage  121  of the substrate support  120 . In example embodiments, because the apparatus may include the purge ring  150  installed at the substrate support  120  without the edge ring, the substrate support  120  with the substrate W may be upwardly moved to the process region. 
     The showerhead structure  130  may inject the source gas, the reaction gas and the purge gas. The purge ring structure  150  may inject the deposition-preventing gas and the additional reaction gas to form the thin film having the uniform thickness on the substrate. 
     After forming the thin film, the substrate support  120  may be downwardly moved. The substrate may be unloaded from the chamber  110  through an exit D 2 . 
       FIG. 5  is a timing chart illustrating a method of depositing a thin film by an ALD process in accordance with example embodiments. 
     Referring to  FIG. 5 , a method of forming the thin film by the ALD process may include introducing the source gas, supplying the purge gas, introducing the reaction gas and supplying the purge gas. The source gas and the reaction gas may be changed in accordance with materials of the thin film. During depositing the thin film, in order to suppress the thin film from being deposited on the bottom surface of the substrate W, the deposition-preventing gas may be continuously supplied through the sub-gas passageway  140   b . The deposition-preventing gas may include an inert gas such as an Ar gas, a He gas, a Ne gas, a Kr gas, a Xe gas, an Rn gas, etc. Further, the additional reaction gas such as a H 2  gas may be supplied simultaneously with the reaction gas. As a result, reactions of the thin film deposited on the edge portion of the substrate W may be controlled. 
       FIG. 6  is a timing chart illustrating a method of depositing a thin film by a CVD process in accordance with example embodiments. 
     Referring to  FIG. 6 , when the purge ring structure  150  may be installed at a CVD apparatus, the source gas, the reaction gas, the deposition-preventing gas and the additional reaction gas may be simultaneously supplied to the CVD apparatus. 
     In example embodiments, the reaction gas and the additional reaction gas may include substantially the same material. 
     According to example embodiments, the apparatus for processing the substrate may include the purge ring structure with the bosses on the inner surface of the purge ring, which may be configured to surround the substrate support, without the edge ring. Therefore, the deposition-preventing gas may be supplied to the edge portion of the bottom surface of the substrate. The bosses may form the gap between the purge ring and the edge portion of the substrate. The gap may function as to selectively supply the deposition-preventing gas and the additional reaction gas to the upper surface of the substrate. As a result, the deposition uniformity of the thin film on the substrate may be improved. 
     The above embodiments of the present disclosure are illustrative and not limitative. Various alternatives and equivalents are possible. The examples of the embodiments are not limited by the embodiments described herein. Nor is the present disclosure limited to any specific type of semiconductor device. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.