Abstract:
A cleaning system comprises a chamber and a particle-removing device. The particle-removing device, arranged outside the chamber, including an ionizer ionizing surrounding gas and spouting the ionized gas and a vacuum unit. Whereby, before an substrate is sent into the chamber, the ionized gas spouted from the ionizer neutralizes electrostatic charges and blowing up particles accumulate on the substrate and the particles are drawn away by the vacuum unit so that the object can be transmitted into the chamber much cleaner.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (1) Field of the Invention  
         [0002]     The invention relates to a cleaning system and more particularly to the cleaning system that utilizes ionized gas to clean an object thereinside.  
         [0003]     (2) Description of the Prior Art  
         [0004]     In manufacturing a liquid crystal display (LCD), it is always an important issue to keep the glass substrate clean and to avoid the particles, which are the major sources of pollution, to contaminate the substrate.  
         [0005]     For example, the circuit pattern on a glass substrate of the LCD is formed by repeatedly performing photo engraving processes on a glass substrate. Typically, the process is performed by plastering the photoresist on the surface of the silicon film of the glass substrate, exposing the photoresist of the glass substrate through a photo mask with a predetermined circuit pattern, developing the hardened sensitized photoresist to remove the undesired part of the photoresist and finally forming the circuit pattern on the surface of the silicon film of the glass substrate by etching.  
         [0006]     If particles exist around the area to be etched before a practical etching begins, then the particles there may act as a hard mask thereafter that prevents the area under the particles from being etched. It impacts the following process and may cause the defects in the product. Obviously, such a hard mask formed by accumulating unexpected particles jeopardize the manufacturing of the LCD.  
         [0007]     Generally, the particles come from the environment, such as operators, working machines or floating dusts in the air. Various causes may make particles to adhere to the surface of the substrate. Some of them are listed as follows: 
        1. The particles floating in the environment drop onto the surface due to the gravity.     2. Attraction (ex: Van der Waals forces) between the particles and the molecules of the silicon film may grasp the particles to settle on the silicon film.     3. Electrostatic force between the surface of the glass substrate and the charged particles may drive the particles to hit on the surface of the glass substrate.        
 
         [0011]     Thus, in practice, after a developing process upon the substrate is completed, the etching process has to be executed within a limited time so that the time for the glass substrate to be exposed to the environment can be reduced and thus the degree of the particles adhering to the substrate can be minimized.  
         [0012]     Moreover, before the etching, various kinds of methods can be utilized to remove the particles, such as the wet cleaning by a supersonic means with a pure water or cleaning liquid, the dry cleaning by a spouting means with a clean gas to blow the particles on the substrate&#39;s surface away, and so on. However, since the wet cleaning has the risk to leave the mist on the surface of the glass substrate so as to incomplete the etching, thus the dry cleaning is preferable to be adopted as the pre-cleaning before the etching process.  
         [0013]     In  FIG. 1 , an etching machine  1  for carrying out a typical etching operation is illustrated. The etching machine  1  is used to etch a glass substrate  10  which has already been coated with photoresist. The etching machine  1  provides a central transmitting chamber  11  having a mechanical arm  12  thereinside. The central transmitting chamber  11  is surrounded by a stocker chamber  13 , a cleaning chamber  15  and several etching chambers  14  (four shown in the figure). The mechanical arm  12  is used to transmit the glass substrates  10  among the stocker chamber  13 , the cleaning chamber  15 , and the etching chambers  14 .  
         [0014]     The stocker chamber  13  is the entrance of the etching machine  1 . The glass substrate  10  is sent to the stocker chamber  13  firstly and transmitted to the cleaning chamber  15  from the stocker chamber  13  for cleaning by the mechanical arm  12 . After the cleaning process, the substrate  10  is sent to the etching chamber  14  for etching.  
         [0015]     The cleaning chamber  15  usually provides a dry-cleaning machine, which is usually sized to meet the size of the glass substrate. As the substrate  10  is moved into the cleaning chamber  15 , the dry-cleaning machine thereinside will generate an air knife (a high-pressure flow) to blow over the surface of the substrate  10  at a short distance so as to remove the particles deposited on the surface.  
         [0016]     Nevertheless, there are still following shortcomings in the aforesaid cleaning: 
    1. Before the substrate is sent into the etching chamber  14 , a substantial period of time is needed for the substrate to stay in the cleaning chamber and to transmit among the chambers. This will extend the etching process.     2. The dry-cleaning machine occupies the limited space in the etching machine, such that only a small number of the etching chambers that can be equipped therewith.     3. If the particles lifted by the air knife are not taken away, they may again stick on the cleared area in the etching machine. This will decrease the cleaning efficiency.     4. The direct high-pressure flow to the glass surface may contribute to the static charge accumulation on the glass surface. As a result, those particles are hard to remove due to the electrostatic force. Beside the cleaning efficiency may be reduced, the induced electrostatic discharging may also break down the circuit components.    
 
         [0021]     Accordingly, any effort devoted to improving the cleaning techniques upon the manufacturing of LCD so as to promote the yield is definitely welcome to all the persons in the art.  
       SUMMARY OF THE INVENTION  
       [0022]     One object of the present invention is to provide a cleaning system that can substantially reduce the cleaning time of the substrate prior to an etching process.  
         [0023]     Another object of the present invention is to provide a cleaning system that make a better arrangement of the available working space inside the machine.  
         [0024]     The other object of the present invention is to provide a cleaning system that can integrate different cleaning means for achieving a better cleaning efficiency.  
         [0025]     Moreover, one object of the present invention can also be to provide a cleaning system that can prevent the static charges accumulation on an object.  
         [0026]     For those purposes, the present invention combines of a particle-removing device with a chamber. Before an object or a substrate is sent into the chamber for reaction, the particle-removing device can clean the object by blowing an ionized gas to drive away particles on the surface of the object and, at the same time, vacuum the lifted particles so that they won&#39;t stick back on the surface of the object.  
         [0027]     In the present invention, the cleaning system comprises a chamber and a particle-removing device. The particle-removing device, arranged outside the chamber, including an ionizer ionizing surrounding gas and spouting the ionized gas and a vacuum unit.  
         [0028]     The ionizer may have several sharp electrodes for providing high voltages. The electric field at the tip of the electrode can be increased to ionize the surrounding gas and the ionized gas is then spouted out through the nozzle. The ionizer is connected to a gas piping for providing a pressurized clean dry air or nitrogen to the ionizer. The vacuum unit can connect with a vacuum piping to draw the particles in.  
         [0029]     While an object is sent into the chamber, the ionizer spouts the ionized gas on the object&#39;s surface at an appropriate angle, temperature and pressure through the nozzle of the ionizer. In the present invention, the ionized gas from ionizer can neutralize the accumulated static charges on the surface and remove the electrostatic force, as well as the residual mist. Since the particles on the object&#39;s surface are disturbed, the vacuum unit will draw in the particles away so as not to have the particles stick back on the surface of the object.  
         [0030]     Moreover, this cleaning system can utilize a mechanical arm for carrying the object at a control speed to pass through the ionizer and the vacuum unit. Particle removing is completed during the object passing through the ionizer and the vacuum unit before the object is moved into the chamber for reaction.  
         [0031]     To make the essence of this invention clear, we have details with figures as follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]     The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:  
         [0033]      FIG. 1  is a schematic diagram of a conventional etching machine for carrying out a typical etching operation;  
         [0034]      FIG. 2A  is a perspective view of a preferred cleaning system according to the present invention;  
         [0035]      FIG. 2B  is a schematic diagram to show an action of the particle-removing device of  FIG. 2A ;  
         [0036]      FIG. 3  is a schematic diagram of a first embodiment of the etching machine according to the present invention; and  
         [0037]      FIG. 4  is a schematic diagram of a second embodiment of the etching machine according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]     The invention disclosed herein is directed to a cleaning system. In the following description, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by one skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. In other instance, well-known components are not described in detail in order not to unnecessarily obscure the present invention.  
         [0039]     Referring to  FIG. 2A , a preferred cleaning system in accordance with the present invention is structured as shown. The cleaning system  2 , can be disposed in an etching machine for etching glass substrates  10  coated with photoresist.  
         [0040]     Referring to  FIG. 2B , it is a schematic diagram to show an action of the particle-removing device of  FIG. 2A . As shown, the cleaning system  2  comprises a chamber  20 , a gate  21 , a particle-removing device  22 , a gas piping  23  and a vacuum piping  24 . The gate  21  forms an entrance of the chamber  20 . The particle-removing device  22  is arranged outside the chamber and near the gate  21 . The particle-removing device  22  comprises an ionizer  221  and a vacuum unit  222  is disposed in front of the gate  21 , in which the vacuum unit  222  is positioned closer to the gate  21  than the ionizer  221 .  
         [0041]     The ionizer  221  has several sharp electrodes provided with high voltages so as to generate an electric field around each tip of the electrode and further has a nozzle  2211 . It is noted that, as the voltage of the electrode is increased to a critical level, ionized gas around the electrode will attain a saturation state and spout out through the nozzle  2211 . The ionizer  221  is connected to the gas piping  23  for providing dry clean pressurized air to the ionizer  221 . The pressurized air will flow through the nozzle  2211 , thus mixing the ionized gas, to strike on the substrate  10  located thereunder and disturb particles on the substrate  10 . The vacuum unit  222  is connected to the vacuum piping  25  for drawing the particles lifted or disturbed by the ionizer  221 .  
         [0042]     In operation, the glass substrate  10  passes under the particle-removing device  22  before being sent into the chamber  20  through the gate  21 . The ionizer  221  can spout the ionized gas onto the surface of the glass substrate  10  at an appropriate angle, temperature and pressure through the nozzle  2211 . Beside neutralizing static charges accumulated on the glass substrate  10 , the device can also remove possible local electrostatic fields and residual mists thereon. The vacuum unit  222  will suck in the particles lifted by the ionizer  221  so as to ensure the particles not to stick back on the surface of the object again.  
         [0043]      FIG. 3  is a schematic diagram of a preferred etching machine  3  in accordance with the present invention. The etching machine  3  comprises a transmitting chamber  31 , a stocker chamber  32 , a first mechanical arm  33  and a plurality of etching chambers  34 .  
         [0044]     The differences between the etching machine  3  shown in  FIG. 3  and the conventional machine shown in  FIG. 1  are that there are a plurality of the cleaning systems  2  described in  FIGS. 2A and 2B  applied in the etching machine  3 . Since the cleaning systems  2  are applied in the etching machine  3 , an additional dry-cleaning machine is no more needed to remove the particles on the surface of the glass substrate. Therefore, the place for installing the cleaning room  15  of  FIG. 1  can be kept to mount an additional etching machine.  
         [0045]     In this embodiment, the chamber of the cleaning system  2  is a etching chambers  34 . During the mechanical arm  33  carries the glass substrate  10  to the etching chamber  34  at an appropriate speed via passing the particle-removing device  22 , static charges accumulated on the surface of the substrate can be removed in the way as described above.  
         [0046]     As shown in  FIG. 4 , the chamber of the cleaning system  2  in the second embodiment of the etching machine  3  can be a stocker chamber  32 . The difference to the first embodiment is that, in this second embodiment, while the glass substrate  10  is sent through the stocker chamber  32  at an appropriate speed by a second mechanical arm  35 , the particle-removing device  22  in the chamber  32  can neutralize the static charges accumulated on the surface of the substrate  10  in the way as described above, and can also lift and sweep away the particles on the surface of the substrate  10 . After the surface of the glass substrate  10  is cleaned, the glass substrate  10  is sent into a latter part of the stocker chamber  32  and then carried out of the stocker chamber  32  by the first mechanical arm  33  for further reaction in the etching machine  3 .  
         [0047]     It is clear that the invented process chamber having the cleaning function has various advantages at least as follows: 
    1. The cleaning step of the conventional design before the substrate is sent into the process chamber for etching is omitted in the present invention, such that the operation time of an etching process in the invented etching machine can be reduced.     2. The combination of the particle-removing device and the process chamber can save the space used to be occupied by the cleaning device.     3. By integrating cleaning steps of spouting the ionized gas onto the glass substrate for blowing up the particles by means of the ionizer, neutralizing the charges, and drawing the lifted particles, the particles on the substrate can be removed simultaneously, more easily and effectively     4. Neutralizing the static charges accumulated on the surface of the glass substrate by means of the ionic flow solves the inherent problem of components being damaged by electrostatic discharging on the substrate.    
 
         [0052]     The embodiment above is to illustrate the invention in detail but not to give a specific embodiment. Any modification that doesn&#39;t exceed the essence of the invention should belong to this invention. Thus the invention should be safeguarded according to the claims as follows.  
         [0053]     While the present invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention.