Patent Publication Number: US-10312061-B2

Title: Vacuum apparatus for vacuum treating substrate

Description:
BACKGROUND OF THE DISCLOSURE 
     1. Field of the Disclosure 
     The present disclosure relates to display technical fields, in particular to a vacuum apparatus. 
     2. Description of the Prior Art 
     An electrostatic elimination structure employed in a traditional dry etching apparatus is to produce plasma at a front face of a substrate. The plasma flows to a back face of the substrate naturally in vacuum atmosphere to neutralize charges so that the electrostatic interaction can be eliminated. 
     Along with usage time of the electrode increasing, the electrode surface and the barrier layer surface gradually become smooth, causing a tight adsorption between the substrate and the electrode, so that plasma cannot normally come to the back face of the substrate to eliminate electrostatic interaction. In this way, when supporting pins are raising the substrate gradually, the substrate may be subject to electrostatic adsorption from electrode, and the cooperation of them might cause damages to the substrate. 
     SUMMARY OF THE DISCLOSURE 
     An embodiment of the present disclosure provides a vacuum apparatus which can eliminate electrostatic adsorption between a substrate and an electrode so as to avoid damages to the substrate. 
     In order to achieve the above object, an embodiment of the present disclosure employs the following technical solution: 
     a vacuum apparatus, which comprising: a vacuum cavity; a first electrode and a second electrode located inside the vacuum cavity and opposite to each other; a positioning structure for positioning the substrate between the first electrode and the second electrode; and an electrostatic elimination device. The substrate is positioned closer to the first electrode or the second electrode. The electrostatic elimination device can eliminate electrostatic adsorption between the substrate and first electrode and/or between the substrate and the second electrode by attracting charged particles to a surface of the substrate closer to a side of the first electrode and/or a surface of the substrate closer to a side of the second electrode. 
     Preferably, the first electrode and/or the second electrode are provided with a plurality of gas holes. 
     Optionally, the vacuum apparatus further comprise a gas conveying device which is in connection with the vacuum cavity. The gas conveying device conveys cooling gas at a constant pressure to the substrate through the gas holes. The cooling gas is inert gas. 
     Further optionally, the vacuum apparatus further comprises a detection device for detecting the pressure of the cooling gas. 
     Optionally, the electrostatic elimination device comprises a plasma discharging system and a plasma conveying system, wherein the electrostatic elimination device conveys plasma to the surface of the substrate closer to the side of the first electrode or the surface of the substrate closer to the side of the second electrode. 
     Further optionally, the plasma discharging system comprises an anode and a cathode for generating the plasma. The plasma conveying system comprises a vacuum pump and a conveying conduit. 
     Further, the anode is the first electrode and the cathode is the second electrode. First connecting port(s) and second connecting port(s) are provided between the plasma conveying system and the vacuum cavity. The first connecting port is used to lead plasma generated inside the vacuum cavity outside the vacuum cavity, and the second connecting port is used to convey plasma to the substrate through the gas holes. 
     Optionally, the first electrode is positioned at top of the vacuum cavity and the second electrode is positioned at the bottom of the vacuum cavity. The substrate is positioned above the second electrode and near the second electrode. 
     Further optionally, the positioning structure(s) is (are) supporting pin(s), the second electrode is provided with pin hole(s) matching the supporting pin(s). 
     Optionally, the vacuum apparatus further comprises a barrier layer disposed around the first electrode and/or the second electrode, the thickness of the barrier layer is larger than the thickness of the first electrode and/or the second electrode. 
     The vacuum apparatus provided by the embodiment of the present disclosure includes the vacuum cavity; the first electrode and the second electrode located inside the vacuum cavity and opposite to each other; the positioning structure for positioning the substrate between the first electrode and the second electrode; and an electrostatic elimination device. The substrate is positioned closer to the first electrode or the second electrode. The electrostatic elimination device can eliminate electrostatic adsorption between the substrate and first electrode and/or between the substrate and the second electrode by attracting charged particles to the surface of the substrate closer to the side of the first electrode and/or the surface of the substrate closer to the side of the second electrode. 
     On this basis, the charged particles can neutralize charges on the surface of the substrate, so that the electrostatic adsorption between the substrate and the first electrode and/or the second electrode can be eliminated. In this way, substrate damages caused by electrostatic adsorption can be avoided when the substrate is placed further from the first electrode and/or the second electrode. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order to illustrate embodiment of the present disclosure or technical solution in prior art clearly, the following will simply explain drawings used in the description of the embodiment of the disclosure or the prior art. Obviously, the drawings in the following description only illustrate some embodiments of the present disclosure. As to those skilled in the art, other drawings can be obtained base on these drawings without creative efforts. 
         FIG. 1  is a first schematic view showing a structure of a vacuum apparatus provided by an embodiment of the present disclosure; 
         FIG. 2  is a second schematic view showing a structure of a vacuum apparatus provided by an embodiment of the present disclosure; 
         FIG. 3  is a top view of a vacuum apparatus provided by an embodiment of the present disclosure; 
         FIG. 4  is a third schematic view showing the structure of a vacuum apparatus provided by an embodiment of the present disclosure; and 
         FIG. 5  is a schematic view showing components of an electrostatic elimination device. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE 
     The technical solution in the embodiments of the present disclosure will be described in more detail in conjunction with the attached drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, nor all embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present disclosure. 
     The embodiment of the present disclosure provides a vacuum apparatus, as shown in  FIG. 1 ,  FIG. 2  and  FIG. 5 , which includes: a vacuum cavity  10 ; a first electrode  201  and a second electrode  202  located inside the vacuum cavity  10  and opposite to each other; and positioning structures  30  for positioning the substrate  60 . The substrate  60  is located between the first electrode  201  and the second electrode  202  and is positioned closer to the first electrode  201  or the second electrode  202 . The vacuum apparatus further includes an electrostatic elimination device  90  (shown in  FIG. 5 ). The electrostatic elimination device  90  can eliminate electrostatic adsorption between the substrate  60  and the first electrode  201  and/or between the substrate  60  and the second electrode  202  by attracting charged particles to a surface of the substrate which is closer to a side the first electrode and/or a surface of the substrate which is closer to a side of the second electrode. 
     It should be noted that first, inside the vacuum cavity  10 , the first electrode  201  and the second electrode  202  are positioned opposite to each other, in the following specific way: the first electrode  201  is disposed at the top of the vacuum cavity  10 , the second electrode  202  is disposed at the bottom of the vacuum cavity  10 , or alternatively the first electrode  201  and the second electrode  202  can be both disposed at the side wall(s) of the vacuum cavity  10 , which is not limited herein. 
     Secondly, the positioning structures  30  can be used to adjust the position of the substrate  60  and secure the substrate  60 . If the first electrode  201  and the second electrode  202  are disposed one above the other, one such substrate  60  can only be disposed over the lower electrode, in such case, the positioning structures  30  can be supporting pins. If the first electrode  201  and the second electrode  202  are disposed side by side, two such substrates  60  can be placed at the opposite sides of the two electrodes respectively. In such case, the positioning structures  30  can be clamps. 
     In an embodiment of the present disclosure, the number of the substrates  60  can be adjusted according to the specific positioning of the first electrode  201  and the second electrode  202 . Of course, the securing method of the substrates  60  can be varied accordingly as the positioning way of the substrates  60  varies. 
     Thirdly, when the substrate  60  is positioned closer to the first electrode  201  or closer to the second electrode  202 , a slight gap might be present between the substrate  60  and the first electrode  201  or between the substrate  60  and the second electrode  202 . The presence of the gap can be advantageous to the flowing of the charged particles towards the surface of the substrate  60  so that charges can be neutralized. 
     Fourthly, the electrostatic elimination device  90  can attract the charged particles to the surface of the substrate  60  which is closer to a side of the first electrode  201  or the surface of the substrate  60  which is closer to side of the second electrode  202  in order to eliminate electrostatics. As to the electrostatic elimination device  90 , it can include an additional charges-generating device which is located outside the vacuum cavity  10 , or alternatively, charged particulates such as plasma generated inside the vacuum cavity  10  can be used as the charged particles, which will not be limited herein. 
     Fifthly, when the electrostatic elimination device  90  is used to eliminate charges on the surface of the substrate  60 , if the charges on the substrate  60  are positive charges, the electrostatic elimination device  90  can introduce negative charged particles from negative charges gathering area; if the charges on the surface of the substrate  60  are negative charges, the electrostatic elimination device  90  can introduce positive charged particles from positive charges gathering area. 
     An embodiment of the present disclosure provides a vacuum apparatus. The vacuum apparatus includes a vacuum cavity  10 ; a first electrode  201  and a second electrode  202  located inside the vacuum cavity  10  and opposite to each other; and positioning structures  30  for positioning the substrate  60 . The substrate  60  is located between the first electrode  201  and the second electrode  202  and is positioned closer to the first electrode  201  or the second electrode  202 . The vacuum apparatus further includes an electrostatic elimination device  90 . The electrostatic elimination device  90  can eliminate electrostatic adsorption between the substrate  60  and the first electrode  201  and/or between the substrate  60  and the second electrode  202  by attracting charged particles to a surface of the substrate  60  which is closer to a side the first electrode  201  and/or a surface of the substrate  60  which is closer to a side of the second electrode  202 . 
     On this basis, the charged particles can neutralize the charges on the surface of the substrate  60 , so that the electrostatic adsorption between the substrate  60  and the first electrode  201  and/or the second electrode  202  can be eliminated. In this way, substrate damages caused by electrostatic adsorption can be avoided when the substrate  60  is placed further from the first electrode  201  and/or the second electrode  202 . 
     Based on the above description, preferably, referring to  FIG. 1  and  FIG. 3 , the first electrode  201  and/or the second electrode  202  are provided with a plurality of gas holes  40  therein. 
     The gas holes  40  can be sequentially arranged in shape of annular arrays from outside to inside. On this basis, the gas hole  40  preferably is in shape of a pin hole with a very small diameter which can be smaller than 1 mm. It should be noted that the shape of the gas hole  40  is only schematically depicted; and the embodiment of the present disclosure is not limited by this, as long as it is in shape of thought hole with small diameter. 
     In this way, the gas holes  40  can be used as channels which can convey gaseous substances from the exterior of the vacuum cavity  10  to the interior of the vacuum cavity  10 . Herein, the gaseous substances mainly refer to gas and plasma. 
     The actual number of the gas holes  40  of embodiments of the present disclosure is not limited herein. However, considering a balance problem of the substrate  60  when gas is conveyed to the substrate  60  through the gas holes  40 , it is preferable in embodiments of the present disclosure that the gas holes  40  are symmetrically distributed relative to the first electrode  201  or the second electrode  202 . 
     It should be noted that the positioning of the gas holes  40  is related to the positioning of the first electrode  201  and the second electrode  202 . If the first electrode  201  and the second electrode  202  are disposed one above the other and there is only one substrate  60  in the vacuum cavity  10 , then the gas holes  40  are only disposed in the lower electrode; if the first electrode  201  and the second electrode  202  are disposed side by side and there are two substrates  60  in the vacuum cavity  10 , then the gas holes  40  can be disposed in both of the first electrode  201  and the second electrode  202 . 
     Optionally, the vacuum apparatus further can include a gas conveying device  70  connecting with the vacuum cavity  10 . The gas conveying device  70  can convey cooling gas at a constant pressure to the substrate  60  through the gas holes  40 . The cooling gas is preferably chemically stable inert gas, such as helium or argon and the like. 
     Specifically, the gas conveying device  70  can be connected to a location of the cavity body of the vacuum cavity  10  near the gas holes  40 . For example, when the gas holes  40  are disposed in the bottom electrode inside of the vacuum cavity  10 , the gas conveying device  70  can be connected with the bottom of the vacuum cavity  10 , so that cooling gas can be blown to the substrate  60  through the gas holes  40  in the bottom electrode. 
     It should be noted that the conveying way of cooling gas is constant pressure conveying; that is to say, the pressure applied to the substrate  60  by the cooling gas needs to be kept constant, and the pressures of the cooling gas conveying through different gas holes  40  should be consistent. Considering the cooling gas functions to reduce the temperature of the surface of the substrate  60 , therefore, the pressure of the cooling gas should be kept within a certain range, so that the damages to the substrate  60  by excessive pressure can be avoided. 
     On this basis, the vacuum apparatus may further include a detection device  80  for detecting the pressure of the cooling gas. 
     Furthermore, referring to  FIG. 1 ,  FIG. 2  and  FIG. 5 , the vacuum apparatus may further comprises a barrier layer  50  disposed around the first electrode  201  and/or the second electrode  202 ; wherein the thickness of the barrier layer  50  is larger than the thickness of the first electrode  201  and/or the second electrode  202 . 
     Therefore, during the process of conveying cooling gas at constant pressure to the substrate  60  through the gas holes  40 , the provision of the barrier layer  50  can effectively prevent losing of the cooling gas so that the cooling gas can be kept between the substrate  60  and the first electrode  201  and/or between the substrate  60  and the second electrode  202  stably. 
     Beside, according to different functions of vacuum apparatuses, the vacuum cavity  10  can be a vacuum reaction cavity, that is, in operation, the vacuum cavity  10  needs to be fed with reactive gas, and in this case the vacuum apparatus may further include a gas inlet device for conveying reactive gas. Because the reactive gas needs to involve in reaction, the gas inlet device can be connected to the middle location of the cavity body of the vacuum cavity  10 , that is to say, located between the first electrode  201  and the second electrode  202 , so that the reactive gas can be fed between the first electrode  201  and the second electrode  202  to react. 
     Optionally, the electrostatic elimination device  90  may comprise a plasma discharging system  901  and a plasma conveying system  902 . The electrostatic elimination device  90  may convey plasma to the surface of the substrate closer to a side of the first electrode  201  or the surface of the substrate  60  closer to a side of the second electrode  202 . 
     Herein, the plasma discharging system  901  can be used to produce plasma, while the plasma conveying system  902  can be used to convey plasma. 
     In detail, the plasma can be derived from outside of the vacuum cavity  10 , or alternatively can be derived from inside of the vacuum cavity  10 . It should be noted that when the plasma is derived from outside of the vacuum cavity  10 , an additional plasma-generating device is needed outside the vacuum cavity  10 , such as plasma generator; when the plasma is derived from inside of the vacuum cavity  10 , the vacuum cavity  10  needs to be a vacuum cavity that can generate plasma, such as a vacuum cavity of a dry etching apparatus. 
     On this basis, the plasma discharging system  901  may include an anode and a cathode for generating plasma. The plasma conveying system  902  might include a vacuum pump  9021  and a conveying conduit  9022 . 
     The cathode and the anode can be metal electrodes. The conveying conduit  9022  can be a conduit of insulating material, such as rubber or resin. 
     Furthermore, in the case that plasma is generated inside the vacuum cavity  10 , the anode is preferably the first electrode  201 ; the cathode is preferably the second electrode  202 . At this time, first connecting port(s)  1010  and second connecting port(s)  1020  are provided between the plasma conveying system  902  and the vacuum cavity  10 . The first connecting port  1010  is used to lead the plasma generated within the vacuum cavity  10  outside the vacuum cavity  10 , and the second connecting port  1020  is used to convey plasma to the substrate  60  through the gas holes  40 . 
     It should be noted that the first connecting port  1010  and the second connecting port  1020  are differentiated by functions of the connecting ports. However, the number of the first connecting port(s)  1010  and the second connecting port(s)  1020  can be determined based on specific situation. Specifically, when only one substrate  60  is placed in the vacuum cavity  10 , either the number of the first connecting port  1010  or the number of the second connecting port  1020  can be one. When two substrates  60  are disposed in the vacuum cavity  10 , either the number of the first connecting port(s)  1010  or the number of the second connecting port(s)  1020  can be two. 
     Considering when electrostatic adsorption occurs between the substrate  60  and the first electrode  201  and/or between the substrate  60  and the second electrode  202 , according to the different position of the substrate  60 , the polarity of the charges on the surface of the substrate  60  can be different. In order to neutralize charges effectively, the first connecting port  1010  is preferably arranged near an electrode with a polarity opposite to the polarity of the charges on the substrate  60 . On this basis, if two substrates  60  are placed in the vacuum cavity  10  at the same time, and one is closer to the first electrode  201 , the other is closer to the second electrode  202 , the polarities of charges on the surfaces of the two substrates  60  are different, then the first connecting port(s)  1010  needs to be connected with the vacuum cavity  10  at different positions. 
     Based on the above description, when the anode and the cathode in the plasma discharging system  901  are the first electrode  201  and the second electrode  202 , the plasma generated in the vacuum cavity  10  can be applied to the electrostatic elimination device  90  as an ion source. 
     On this basis, the conveying conduit  9022  may further include an branch leading to the outside of the vacuum cavity  10 , therefore, the vacuum pump  9021  and the conveying conduit  9022  can be used to effectively drain plasma and other substances out of the interior of the vacuum cavity  10 , so that the vacuum degree of the vacuum cavity  10  can be ensured. 
     Preferably, the first electrode  201  is located at top of the vacuum cavity  10 , and the second electrode  202  is located at the bottom of the second electrode  202 . The substrate  60  is located above the second electrode  202  and is placed near the second electrode  202 . 
     In this case, the gas holes  40  can only be provided in the second electrode  202  and the conveying conduit  9022  can be connected from the middle of the cavity body of the vacuum cavity  10  to the bottom of the vacuum cavity  10 , so that the plasma generated in the vacuum cavity  10  can flow through the gas holes  40  towards the surface of the substrate  60  smoothly. 
     In this process, the plasma can pass through the gas holes  40  from outside to inside to convey to the surface of the substrate  60 . That is to say, the gas holes  40  located at the outer portion can first release the plasma, while gas holes  40  located at the inner portion can subsequently release the plasma, and so on. In this way, the plasma can pass through the gas holes  40  from outside to inside to reach the surface of the substrate  60 , so that the effect of eliminating electrostatic adsorption can be achieved. Therefore, the substrate  60  can be placed on the second electrode  202  naturally. 
     On this basis, the positioning structures  30  can be supporting pins. The supporting pins can have the function of lifting and lowering. By lifting the support pins, the substrate  60  can be raised away from the second electrode  202 . Because the electrostatic adsorption between the substrate  60  and the second electrode  202  can be eliminated, there is no possibility of damaging the substrate  60  during lifting. In this case, the second electrode  202  further has pin holes therein matching the supporting pins. 
     The following is an embodiment to illustrate the function of eliminating electrostatics of the vacuum apparatus. The vacuum apparatus is for instance a plasma dry etching apparatus. 
     As shown in  FIG. 4 , the plasma dry etching apparatus includes a first electrode  201  at the top of the vacuum cavity  10  and a second electrode  202  at the bottom of the vacuum cavity  10 . The second electrode  202  is provided with a plurality of gas holes  40  and pin holes through which a plurality of symmetrically distributed supporting pins (positioning structure  30 ) can pass and can be lifted or lowered. A barrier layer  50  is disposed around the second electrode  202 . The thickness of the barrier layer  50  is somewhat larger than the thickness of the second electrode  202 . 
     On this basis, the plasma dry etching apparatus further comprises: a gas inlet device for conveying reactive gas; a gas conveying device  70  for conveying cooling gas; and a plasma conveying system  902  for connecting the middle of the cavity body of the vacuum cavity  10  and the bottom of the vacuum cavity  10 . Both of the gas conveying device  70  and the plasma conveying system  902  can be connected with the gas holes in the second electrode  202 . 
     In this way, during operation of the plasma dry etching apparatus, the substrate  60  needing to be plasma dry etched can be placed on the supporting pins and is adjusted to the position aligned with the barrier layer  50 . As the plasma dry etching begins, a certain voltage is applied between the first electrode  201  and the second electrode  202 . At meantime, the gas inlet device is conveying reactive gas such as oxygen into the vacuum cavity  10  and the gas conveying device  70  is conveying cooling gas such as helium to the back face of the substrate  60  through the gas holes  40  in the second electrode  202 . Under the action of a high voltage electric field, the reactive gas can be highly ionized so that oxygen plasma can be formed. On this basis, on one hand, part of the oxygen plasma in the vacuum cavity  10  is used to dry etch the substrate  60 ; on the other hand, in order to ensure the vacuum degree of the cavity body, the gas, plasma and impurity particles in the cavity need to be discharged in time. At this time, the vacuum pump  9021  in the plasma conveying system  902  can be used to pump them out, and discharge most of them from the vacuum cavity  10  through a branch of the conveying conduit  9022 . When the plasma dry etching is about to be finished, the pumped plasma can further be led to the gas holes  40  in the second electrode  202  through the conveying conduit  9022 , and is conveyed to the surface of the substrate  60  through gas holes  40  to neutralize charges on the surface of the substrate  60 , thereby eliminating the electrostatic adsorption. 
     The embodiment of the present disclosure can neutralize charges on surface of the substrate  60  with plasma generated by the plasma dry etching apparatus itself, eliminating the electrostatic adsorption between the substrate  60  and the second electrode  202  so that the damages to the substrate caused by the electrostatic adsorption can be avoided. At the same time, the plasma generated within the vacuum cavity can be effectively utilized. This embodiment is easy and simple to practice. 
     Furthermore, the above embodiment is taking a plasma dry etching apparatus as an example; however, the present disclosure is not limited by this. The vacuum apparatus can be any other vacuum apparatus with electrostatic adsorption phenomenon, such as a vapor deposition apparatus which will not be described in more detail. 
     The above description is only embodiment of the present disclosure. However, the protection scope of the present disclosure is not limited by this. Those skilled in the art can easily envision variations or alternations to the embodiment within the technical scope of the present disclosure and those variations or alternations are within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure is only based on the protection scope of the claims.