Abstract:
A method of forming a layer including disposing a first target and a second target to face each other with a first space therebetween, disposing a substrate to face the first space, generating plasma between the first target and the second target to perform sputtering on the substrate, disposing a capture net between the substrate and the the first space, and capturing anions and/or electrons that propagate toward the substrate from the first space.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2014-0080571, filed on Jun. 30, 2014, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    This disclosure relates to sputtering apparatuses and/or methods for forming a thin film. 
         [0004]    2. Description of the Related Art 
         [0005]    In order to fabricate a semiconductor, or a display device, thin films may be formed and patterned. Forming a high quality thin film having substantially no or a relatively low level of damage is desirable to form a fine pattern by patterning the thin film. The thin film may be formed by various methods such as chemical vapor deposition (CVD), atomic layer deposition, and sputtering depending upon material of thin film or an objective of forming the thin film. The sputtering is one of evaporation technique, and generates plasma at a relatively low temperature by accelerating a gas such as argon, colliding the same to a target, and having atoms or molecules emit from the targets. The emitted atoms or molecules are used to form a thin film layer on a substrate. 
         [0006]    When the thin film is formed by the sputtering, ions, electrons, or the like as well as the material for forming the thin film are emitted. The emitted ions and/or electrons collide with a substrate thereby causing problems such as damage to the thin film to be formed or other thin films previously formed on the substrate. 
       SUMMARY 
       [0007]    Some example embodiments provide sputtering apparatuses which may prevent or mitigate damage to a thin film caused by a by-product when forming a thin film according to a sputtering method, and methods of forming a thin film using the same. 
         [0008]    According to an example embodiment, the sputtering apparatus includes a first target mounting portion, a second target mounting portion disposed to face the first target mounting portion with a first space therebetween, a first electrode disposed a second space from the first target mounting portion; a second electrode disposed a third space from the second target mounting portion, the second electrode being opposite to the first electrode, a power supply portion applying a voltage between the first target mounting portion and the first electrode and between the second target mounting portion and the second electrode, a substrate mounting stand disposed to face an area between the first target mounting portion and the second target mounting portion; and a capture net disposed between the first space and the substrate mounting stand. 
         [0009]    According to some example embodiments, the capture net may be configured to capture at least one of electrons and anions. The capture net may be configured to be grounded. The capture net may be made of a material having an electrical conductivity. The material for the capture net may have a relative dielectric constant of less than or equal to about 1.2. The material for the capture net may include at least one of silver, copper, lead, aluminum, and palladium. 
         [0010]    According to some example embodiments, the capture net may have at least one shape of a lattice, a spider web, and a shape of binding a plurality of concentric circles with radiation lines connecting the same. 
         [0011]    According to some example embodiments, the first target mounting portion and the second target mounting portion may each function as magnets, and may form a DC magnetic field therebetween. 
         [0012]    According to some example embodiments, at least one of DC, RF (radio frequency), or a pulsed electric field may be applied between the first target mounting portion and the first electrode and between the second target mounting portion and the second electrode. 
         [0013]    According to an example embodiments, a method of forming a layer includes disposing a first target and a second target to face each other with a first space therebetween, disposing a substrate to face the first space, generating plasma between the first target and the second target to perform sputtering on the substrate, capturing at least one of anions and electrons that propagate toward the substrate from the first space. The capturing may include disposing a capture net between the first space and the substrate and grounding the capture net. 
         [0014]    The capture net may include a material having a relative dielectric constant of less than or equal to about 1.2. The material for the capture net may include at least one of silver, copper, lead, aluminum, and palladium. The capture net may have at least one shape of a lattice, a spider web, and a shape binding a plurality of concentric circles with radiation lines connecting the same. 
         [0015]    According to methods of some example embodiments, the disposing, the generating and the capturing cooperatively form an ITO layer having a thickness of less than or equal to about 100 nm on the substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic view of a sputtering apparatus according to an example embodiment. 
           [0017]      FIG. 2  is a graph showing an amount of electrons arriving at a substrate in a sputtering apparatus according to an example embodiment and a sputtering apparatus in which a capture net is not provided (comparative example). 
           [0018]      FIG. 3  is a graph showing conductivity of several thin films formed under various conditions using a sputtering apparatus in which a capture net is not provided (comparative example). 
           [0019]      FIG. 4  is a graph showing conductivity of several thin films formed under the various conditions using a sputtering apparatus according to an example embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Various example embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which some example embodiments are shown. As those skilled in the art would realize, the described example embodiments may be modified in various different ways, all without departing from the spirit or scope of example embodiments. Rather, these example embodiments are merely provided so that this disclosure will be thorough and complete, and will fully convey the scope of example embodiments to those skilled in the art. In the drawings, the sizes and relative sizes of the various layers and regions may have been exaggerated for clarity. Like numerals refer to like elements throughout. 
         [0021]    It will be understood that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
         [0022]    It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of example embodiments. 
         [0023]    Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
         [0024]    The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0025]    Hereinafter, some example embodiments will be explained in further detail with reference to the accompanying drawings. 
         [0026]    First, referring to  FIG. 1 , a sputtering apparatus according to an example embodiment is described. 
         [0027]      FIG. 1  is a schematic view of a sputtering apparatus according to an example embodiment. 
         [0028]    The sputtering apparatus according to an example embodiment includes a substrate mounting unit  10 , a plasma generating unit  20 , and an ion and electron capture unit  30  provided between the substrate mounting unit  10  and the plasma generating unit  20 . The substrate mounting unit  10 , the plasma generating unit  20 , and the ion and electron capture unit  30  are provided in a process chamber (not shown). 
         [0029]    The substrate mounting unit  10  includes a substrate mounting stand  12 , on which a substrate  11  is to be placed. 
         [0030]    The plasma generating unit  20  includes target mounting portions  210  and  220  facing each other and mounted with respective targets  211  and  221 , the opposing electrodes  241  and  242  disposed a desired (or alternatively, predetermined) interval from respective targets  211  and  221 , and a power supply  230  applying a desired (or alternatively, predetermined) voltage between the target mounting portions  210  and  220  and the opposing electrodes  241  and  242 . The targets  211  and  221  are respectively mounted on the target mounting portions  210  and  220 . When the power supply  230  applies a desired (or alternatively, predetermined) voltage between the targets  211  and  221  and the opposing electrodes  241  and  242 , the targets  211  and  221  may be configured to act as negative electrodes, and the opposing electrodes  241  and  242  may be configured to act as positive electrodes. The target mounting portions  210  and  220  each may act as magnets, and form a DC magnetic field (H) between the targets  211  and  221  facing each other. The electric field formed between the target mounting portions  211  and  221  and the opposing electrodes  241  and  242  may be, for example, a DC, an RF (radio frequency), or a pulsed electric field. In the plasma generating unit  20  according to the present example embodiment, secondary electrons  43  emitted from the surface of the targets  211  and  221  and/or electrons generated during discharge may move around the direct current magnetic field formed between the targets  211  and  221  by Lorentz force, move back and forth between the pair of targets  211  and  221 , and collide with plasma generating gas atoms such as argon, thereby accelerating plasma generation. Thus, plasma  41  may be formed substantially within an area between the targets  211  and  221 , and the substrate  11  may be disposed outside the area between the targets  211  and  221  (hereinafter, “a plasma forming area”). Cations  44  generated by collision of the plasma generation gas atom and electrons may be accelerated toward and collide with the targets  211  and  221 , which act as negative electrodes, to emit atoms or molecules  42  of the targets  211  and  221 . The emitted atoms or molecules  42  of the targets  211  and  221  may be deposited on the substrate  11  to form a thin film. In this case, some of the electron or anions generated in the plasma forming area may be scattered toward the substrate  11  and cause damage to the thin film to be formed or previously formed on the substrate  11 . 
         [0031]    Although the sputtering apparatus according to the present example embodiment includes the pair of opposing electrodes  241  and  242  and target mounting portions  210  and  220 , the configurations of opposing electrodes and the target mounting portions are not limited thereto. For example, the opposing electrodes and the target mounting portions may be disposed in a plurality of pairs. When the plurality of pairs of opposing electrodes and target mounting portions are disposed, the time for forming a thin film may be shortened, and thus damage to the thin film may be reduced. 
         [0032]    In the sputtering apparatus according to an example embodiment, the ion and electron capture unit  30  is disposed between the plasma generating unit  20  and the substrate mounting unit  10  in order to prevent or mitigate the electrons or anions generated in the plasma forming area from scattering toward the substrate  11  and damaging the thin film to be formed or previously formed on the substrate  11 . 
         [0033]    The ion and electron capture unit  30  includes a capture net  31  and a discharging line  32  for discharging the captured electrons or ions. The capture net  31  may have a mesh type structure. The discharging line  32  discharges electrons and/or anions from the sputtering apparatus. For example, the discharging line  32  may be grounded. The capture net  31  may have various shapes, for example, a lattice shape, a spider web shape, a shape of binding a plurality of concentric circles and radiation lines connecting the same, etc. The material for the capture unit  30  may include any material as long as it is electrically conductive. For example, silver, copper, lead, aluminum, palladium, or the like are less affected by the magnetic field of the plasma forming area and have relatively good characteristics as a material for a capture portion  30  because such materials have a relatively good electrical conductivity and a low relative dielectric constant of less than or equal to about 1.2. 
         [0034]    A method of forming a thin film using the sputtering apparatus according to an example embodiment is explained. 
         [0035]    First, the substrate  11 , on which a thin film is to be formed, is placed on the substrate mounting stand  12 . The substrate  11  is placed on the substrate mounting stand  12  using vacuum adsorption or using other fastening means. The targets  211  and  221  are mounted to face each other in the target mounting portions  210  and  220 . The targets  211  and  221  are mounted to be electrically connected with the target mounting portions  210  and  220 . 
         [0036]    Then power is supplied to the plasma generating unit  20  to generate plasma such that the sputtering is performed. Atoms or molecules emitted from the target through the sputtering may be deposited on the substrate. In this case, some electrons and anions among the electrons and anions generated by the plasma generating unit  20  may propagate toward the substrate  11 , may be captured by the capture net  31  of the ion and electron capture unit  30 , and be discharged through the discharging line  32 . As atoms or molecules emitted from the target through the sputtering are electrically neutral, most of the emitted atoms or molecules pass through the capture net  31  and arrive at the substrate  11 . 
         [0037]    When the sputtering is performed for a desired (or alternatively, preset or predetermined) time to provide a thin film having a desirable thickness, the power supply is stopped, and the substrate  11  is dismounted from the substrate mounting stand  12  and is taken out. 
         [0038]    When an ITO layer is formed using a sputtering apparatus according to an example embodiment, a desired time for forming the ITO layer having a thickness of less than or equal to about 100 nm, for example, of less than or equal to about 10 nm may be relatively shorten. Thus, the ITO layer may be less damaged. 
         [0039]      FIG. 2  is a graph showing an electron amount arriving at a substrate in a sputtering apparatus according to an example embodiment and a sputtering apparatus in which a capture net is not provided (comparative example). 
         [0040]    As shown in  FIG. 2 , as the sputtering power is increased, the electron amount arriving at the substrate proportionally increases, regardless of the example embodiment or the comparative example. However, the example embodiment shows a lesser electron amount arriving at the substrate compared to that of the comparative example. Accordingly, this graph shows that the ion and electron capture unit  30  of the example embodiment prevents or mitigates anions and electrons from arriving at the substrate. 
         [0041]      FIG. 3  is a graph showing conductivity of several thin films formed under various conditions using a sputtering apparatus in which a capture net is not provided (comparative example); and  FIG. 4  is a graph showing conductivity of several thin films formed under the various conditions using a sputtering apparatus according to an example embodiment. 
         [0042]    According to the comparative example of  FIG. 3 , current densities change between about 1.0E-04 and about 1.0E-06 according to sputtering conditions when a voltage of −5 V is applied. According to the example embodiment of  FIG. 4 , current densities are around 1.0E-07 when a voltage of −5 V is applied and change within a relatively small range even if sputtering conditions change, compared to the comparative example of  FIG. 3 . Further, referring to  FIG. 4 , the curves are closely distributed within a narrow range of current density values compared to those of  FIG. 3 . This means that the thin film formed using a sputtering apparatus according to an example embodiment has relatively uniform electrical characteristics regardless of the sputtering condition. This also means that the sputtering process using the sputtering apparatus according to an example embodiment may have a relatively wide process margin. 
         [0043]    As stated above, the high-quality thin film may be fabricated due to a wide process margin provided by the sputtering apparatus according to an example embodiment. 
         [0044]    While this disclosure has been described in connection with what is presently considered to be practical example embodiments, it is to be understood that example embodiments are not limited to the disclosed example embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.