Abstract:
A photoresist stripping apparatus and a corresponding method for removing photoresist layers after a patterned polyimide layer is developed. The photoresist-stripping apparatus includes a transporting unit, a stripping unit, a washing unit, a drying unit and a control unit. The transporting unit connects the stripping unit, the washing unit and the drying unit. The control unit is responsible for controlling the transport sequence and timing of the transporting unit. The method of stripping the photoresist layer off the OLED panel includes providing a stripping solution to the stripping unit to remove photoresist layers. The OLED panel is jet-cleaned with a washing solution in the washing unit so that any residual stripping agent is removed. Finally, the surface of the OLED panel is blown dry.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the priority benefit of the allowed U.S. patent application Ser. No. 10/465,744, filed on Jun. 18, 2003, which claims the priority benefit of U.S. Pat. No. 6,613,156, filed on Jan. 23, 2001. The U.S. Pat. No. 6,613,156, filed on Jan. 23 claims the priority of Taiwan Application No. 89217656, filed on Oct. 12, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of Invention  
           [0003]    The present invention relates to an apparatus and corresponding method for stripping off a photoresist layer. More particularly, the present invention relates to an apparatus and corresponding method for stripping off a photoresist layer after a patterned polyimide layer is developed.  
           [0004]    2. Description of Related Art  
           [0005]    Organic light-emitting display (OLED) is a self-illuminating, high brightness, high contrast, wide viewing angle, low driving voltage and high response rate device. In fact, OLED is a new generation of flat panel display that holds great promise in the near future. However, due to immature techniques, many technical aspects for forming an OLED device remain unresolved. Hence, only one of the Japanese companies, Pioneer, has developed and put up some OLED device in some of their small dimensional products with a small scale mass production.  
           [0006]    Photoresist stripping is a process normally used in the last step of a photolithography for producing a semiconductor or display device. The purpose of the photoresist stripping is to remove the photoresist protective cover used in a previous pattern etching so that no residual photoresist is remained to affect the next process of photolithography. Hence, a clean substrate with circuit pattern thereon is obtained. However, for each photoresist stripping after the formation of, for example, the electrode connection layer, the indium-tin-oxide (ITO) anode layer and the isolation layer on each OLED panel, some residual photoresist material will remain on the OLED panel. This is because the ITO substrate used in the OLED panel has a rougher surface than a conventional epitaxial silicon substrate that forms semiconductor circuits. Consequently, residual photoresist can more readily stick on the surface of the ITO panel. Once photoresist remains on the panel surface, especially in the ITO anode region, subsequent vapor deposition of organic light-emitting material and cathode material will be tricky. Dark spots may appear on the display panel and quality of the display may considerably decline. In addition, the subsequently deposited organic light-emitting layer is relatively thin. The non-uniformly distributed residual photoresist on the panel may create a non-uniform electric field that can lead to possible device short-circuiting and decreased the operating lifetime of the device.  
           [0007]    In general, a photoresist layer is used to pattern a non-photosensitive polyimide layer. Polyimide is a material having high thermal stability, physical stability, electrical stability and photoelectric stability. Ultimately, the OLED panel with a polyimide layer can have better light-emitting stability and a longer lifetime. The patterning process includes coating a polyimide or polyimide precursor over a substrate and then coating a photoresist layer over the polyimide layer. A series of operations such as pre-baking, exposure, post-exposure baking, photoresist developing, photoresist stripping, high-temperature baking is sequentially conducted to form a pattern in the polyimide layer. However, the polyimide is apt to damage by the alkaline stripping agent such as KOH before the ultimate step of high-temperature baking. Hence, the selection of stripping agent and the control of stripping time are significantly important to OLED lithography process. Photoresist stripping in a conventional integrated circuit and photoelectric fabrication process includes spinning a silicon substrate by attaching the substrate onto a suction spinner. While the silicon substrate is spinning, stripping solution and rinsing solution are sprayed simultaneously and continuously. Finally, the silicon substrate is spun dry at a high speed. However, as size of a display panel increases and with glass substrate replacing silicon substrate, a conventional spinning spinner can hardly support such heavy loading and the centrifugal force created at high spinning rate can be dangerous. Therefore, the aforementioned photoresist stripping process is bound to remain some residual photoresist and lead to a great reduction of process yield. An alternative method is to immerse the display panel in various baths containing alkaline solution and then rinsing with water thereafter. Yet, this is a non-continuous process because the display panel has to be taken out, either manually or mechanically, after each immersion treatment. Hence, not only is the total processing time increased, but the operation of large display panel is very troublesome and inconvenient too. Moreover, if the display panels are handled manually in the stripping process, damages caused by delays or human errors are additional factors that must be considered in the continuous mass production line. In brief, most conventional setup can hardly well control photoresist stripping and ensure an acceptable quality in mass production scale of OLED.  
           [0008]    Furthermore, the polyimide used for producing the OLED panel must go through a final baking at a high temperature of between 220˜350° C. Only after the final baking step will the polyimide layer have the high electrical, mechanical, thermal and chemical stability an OLED panel required. Before the final thermal baking, chemical stability of polyimide is not well established. Hence, the polyimide material is apt to damages by corrosive alkaline stripping agents. In other words, the alkaline solution such as sodium hydroxide and potassium hydroxide used for stripping photoresist in the conventional technique may often lead to partial stripping and dissociation of the polyimide layer on the OLED panels. To diminish polyimide damage on the OLED panels, timing of the photoresist stripping has to be accurately monitored and controlled, and stripping agents has to be carefully selected. In conclusion, the stripping process of the polyimide layer on the OLED panel has to be designed to increase yield, stability, automaticity and capacity.  
         SUMMARY OF THE INVENTION  
         [0009]    Accordingly, the present invention provides an apparatus and corresponding method for stripping a photoresist layer off an organic light-emitting display (OLED) panel. The stripping process not only can strip a photoresist layer off an OLED panel with high degree of surface cleanliness, but also can operate continuously to deal with display panel of various sizes. Hence, the setup and method is suitable for stripping photoresist layer from OLED panel in mass production.  
           [0010]    The invention provides a method of photoresist stripping for an organic light-emitting display (OLED) panel. In the method, at least one n-butyl acetate treatment of the OLED panel is provided. Then, at least one isopropyl alcohol treatment of the OLED panel is provided. Next, the surface of the OLED panel is cleaned with de-ionized water one or more times. Thereafter, the de-ionized water is removed from the surface of the OLED panel by using an air knife.  
           [0011]    In one embodiment of the invention, the step of treating the OLED panel with n-butyl acetate includes spraying the liquid onto the OLED panel surface or immersing the entire OLED panel into a pool of the liquid.  
           [0012]    In one embodiment of the invention, the step of treating the OLED panel with n-butyl acetate included immersing the entire OLED panel into a pool of the liquid.  
           [0013]    In one embodiment of the invention, the step of treating the OLED panel with n-butyl acetate includes spraying the liquid onto the OLED panel surface.  
           [0014]    In one embodiment of the invention, the step of treating the OLED panel with n-butyl acetate includes a combination of spraying the liquid onto the OLED panel surface and immersing the entire OLED panel into a pool of the liquid.  
           [0015]    In one embodiment of the invention, the step of treating the OLED panel with isopropyl alcohol includes immersing the entire OLED panel into a pool of the liquid.  
           [0016]    In one embodiment of the invention, the step of cleaning the OLED panel with de-ionized water includes spraying the liquid onto the OLED panel surface.  
           [0017]    In one embodiment of the invention, the step of using n-butyl acetate to strip photoresist material from the surface of the OLED panel further includes shuttling the OLED panel inside the n-butyl acetate reaction chamber.  
           [0018]    The invention provides an apparatus of photoresist stripping for an organic light-emitting display (OLED) panel. The apparatus includes, for example but not limited to, a stripping unit, a washing unit, a blow-drying unit, a transporting unit and a control unit. The stripping unit provides at least one n-butyl acetate treatment of the OLED panel and/or at least one isopropyl alcohol treatment of the OLED panel to remove photoresist on the surface of the OLED panel. The washing unit is provided for spraying a cleaning solution to remove n-butyl acetate and/or isopropyl alcohol on the surface of the OLED panel. The blow-drying unit is provided for drying the OLED panel. The transporting unit is provided for continuously transferring OLED panels to the stripping unit, the washing unit and the blow-drying unit. The control unit is provided for controlling the sequence and timing of transfer of OLED panels to each treatment unit.  
           [0019]    In one embodiment of the invention, the apparatus further includes a carrier unit for holding waiting OLED panels or providing a buffer region for holding OLED panel after photoresist development so that the OLED panels may be directly transferred to a subsequent module.  
           [0020]    In one embodiment of the invention, the apparatus further includes a downloading unit for holding photoresist stripped OLED panels or providing a buffer region for holding photoresist stripped OLED panels so that the photoresist stripped OLED panels may be directly transferred to a high-temperature baking module.  
           [0021]    In one embodiment of the invention, the stripping unit includes at least one n-butyl stripping baths and at least one isopropyl alcohol stripping baths.  
           [0022]    In one embodiment of the invention, the n-butyl acetate stripping baths are positioned to form a serial configuration, a parallel configuration or a mixture of bath.  
           [0023]    In one embodiment of the invention, the isopropyl alcohol stripping baths are positioned to form a serial configuration, a parallel configuration or a mixture of bath.  
           [0024]    In one embodiment of the invention, the isopropyl alcohol stripping baths are positioned behind the n-butyl acetate stripping baths.  
           [0025]    In one embodiment of the invention, the washing unit includes a plurality of washing baths. Furthermore, the cleaning baths are positioned serially.  
           [0026]    The invention also provides an apparatus of photoresist stripping for an organic light-emitting display (OLED) panel. The apparatus includes, for example but not limited to, a stripping unit, a washing unit, and a blow-drying unit. The stripping unit provides at least one n-butyl acetate treatment of the OLED panel and/or at least one isopropyl alcohol treatment of the OLED panel to remove photoresist on the surface of the OLED panel. The washing unit is provided for spraying a cleaning solution to remove n-butyl acetate and/or isopropyl alcohol on the surface of the OLED panel. The blow-drying unit is provided for drying the OLED panel.  
           [0027]    In one embodiment of the invention, the apparatus further includes a transporting unit for continuously transferring OLED panels to the stripping unit, the washing unit and the blow-drying unit.  
           [0028]    In one embodiment of the invention, the apparatus further includes a control unit for controlling the sequence and timing of transfer of OLED panels to each treatment unit.  
           [0029]    In brief, this invention provides a photoresist stripping device and a corresponding photoresist stripping method. The apparatus and the corresponding method not only can remove a photoresist layer from the surface of an OLED panel with high cleanliness, but can also strip photoresist layer from OLED panels having various sizes en-mass in a continuous process.  
           [0030]    It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The following drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
         [0032]    [0032]FIG. 1 is a diagram showing the layout of various components in a photoresist stripping device according to this invention;  
         [0033]    [0033]FIG. 2 is a side view of a transport roller unit used in the stripping device according to the invention;  
         [0034]    [0034]FIG. 3A is a sketch of the n-butyl acetate stripping bath used in the stripping device according to the invention;  
         [0035]    [0035]FIG. 3B is a sketch of the isopropyl alcohol cleaning bath used in the stripping device according to the invention;  
         [0036]    [0036]FIG. 4 is a sketch of the washing bath used in the stripping device according to the invention;  
         [0037]    [0037]FIG. 5 is a block diagram that shows the layout of the various components of the photoresist stripping device and the operating sequence for conducting the stripping operation according to one embodiment of the invention;  
         [0038]    [0038]FIG. 6 is a block diagram that shows the layout of the various components of the photoresist stripping device and the operating sequence for conducting the stripping operation according to another embodiment of the invention; and  
         [0039]    [0039]FIG. 7 is a block diagram that shows the layout of the various components of the photoresist stripping device and the operating sequence for conducting the stripping operation according to one another embodiment of the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0040]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.  
         [0041]    [0041]FIG. 1 is a diagram showing the layout of various components in a photoresist stripping device according to this invention. As shown in FIG. 1, the photoresist stripping device  100  includes, for example but not limited to, a transporting unit  200  that links up three operating units including a stripping unit  300 , a washing unit  400  and a drying unit  500 . A control unit  600  is also required to control the transport sequence and timing of the transporting unit  200 . In another embodiment of the invention, the photoresist stripping device  100  may only includes the stripping unit  300 , the washing unit  400  and the drying unit  500 , in which the transporting unit  200  or the control unit  600  may be optionally added.  
         [0042]    The transporting unit  200  is responsible for moving OLED panels into the stripping unit  300 , the washing unit  400  and the drying unit  500  sequentially and continuously. FIG. 2 is a side view of a transport roller unit used in the stripping device according to the invention. As shown in FIG. 2, the transporting unit  200  includes a roller unit  210 . Each roller unit  210  further includes an axle  220  and a pair of rollers  230  attached to each end of the axle  220 . Each roller  230  has an inner edge  240  serving as a load support and an outer edge  250  serving as a retainer. The load supporting inner edge  240  is used for supporting OLED panels  10  while the outer edge  250  is responsible for restricting the horizontal movement of the OLED panels  10  supported by the rollers  230 . The OLED panels  10  are transported from one location to another via the rolling action provided by the rollers  230 .  
         [0043]    As shown in FIG. 1, the OLED panels  10  are transported by the transport roller unit  210  from the developing unit  700  to the stripping unit  300 . The stripping unit  300  at least includes an n-butyl acetate (NBA) stripping bath  310  and an isopropyl alcohol (IPA) stripping bath  320 . The OLED panels  10  are transported into the n-butyl acetate stripping bath  310 . FIG. 3A is a sketch of the n-butyl acetate stripping bath used in the stripping device according to the invention. As shown in FIG. 3A, the NBA bath includes a storage tank  312 , a liquid supply system  314  and a reaction chamber  316 . The storage tank  312  is a storage area for n-butyl acetate. NBA liquid in the storage tank  312  is transferred to the reaction chamber  316  through the liquid supply system  314 . The NBA liquid reacts with photoresist material on the OLED panels  10  while shuttling inside the reaction chamber  316  to strip off the surface photoresist layer. The shuttling motion of OLED panels  10  inside the reaction chamber  316  serves to even out and quicken the removal of the photoresist material. The liquid supply system  314  pumps the NBA from the storage tank  312  and introduces the NBA into the reaction chamber  316 . By immersion, spraying or partial immersion and spraying of the n-butyl acetate, photoresist on the surface of an OLED panel is gradually dissolved and carried away.  
         [0044]    [0044]FIG. 3B is a sketch of the isopropyl alcohol stripping bath used in the stripping device according to the invention. As shown in FIG. 3B, the isopropyl alcohol stripping bath  320  at least includes an isopropyl alcohol stripping bath  330 . Each isopropyl alcohol stripping bath  330  also includes a storage tank  332 , a liquid supply system  334  and a reaction chamber  336 . The storage tank  332  holds the isopropyl alcohol. Isopropyl alcohol is pumped from the storage tank  332  to the reaction chamber  336  by the liquid supply system  334  so that the OLED panels  10  can be washed. Because isopropyl alcohol has a relatively low boiling point, the OLED panels are washed by immersion rather than by spraying to reduce alcohol vapor generation. In general, the components inside the stripping unit  300  are manufactured using anti-explosion stainless steel for greater safety. An addition waste recycling system may be installed between the n-butyl acetate stripping bath  310  and the isopropyl alcohol stripping bath  320 . In addition, a cooling system may be installed inside the isopropyl alcohol stripping bath  330  to recycle the low boiling point alcohol in line with environmental regulations.  
         [0045]    As shown in FIG. 1, the washing unit  400  is positioned right after the stripping unit  300 . The washing unit  400  is a place in which cleaning solution such as de-ionized water is sprayed on the OLED panels  10  so that any residual isopropyl alcohol is removed. The washing unit  400  has at least one washing bath  410 . FIG. 4 is a sketch of the washing bath used in the stripping device according to the invention. As shown in FIG. 4, each washing bath  410  includes a storage tank  412 , a liquid supply system  414  and a reaction chamber  416 . The storage tank  412  holds de-ionized water. De-ionized water is pumped from the storage tank  412  to the reaction chamber  416  by the liquid supply system  414 . Any isopropyl alcohol is removed by spraying de-ionized water onto the surface of the OLED panels  10 . In general, a design having two serially connected washing baths  340  and  350  are employed so that the OLED panels  10  are washed twice in sequence. In addition, the used de-ionized water in the second washing bath  350  can be reused by collecting and feeding to the first washing bath  340 . In this way, some water resource is saved.  
         [0046]    As shown in FIG. 1, the drying unit  500  is positioned after the washing unit  400 . The drying unit  500  is responsible for removing residual de-ionized water from the surface of the OLED panels  10 . An air knife blow-drying method may be employed in the drying unit  500 .  
         [0047]    The control unit  600  is a controlling device responsible for coordinating the sequence and timing of the transporting unit  200  so that appropriate treatments of the OLED panels  10  are provided by the stripping unit  300 , the washing unit  400  and the drying unit  500 . In addition, the control unit may provide a proper engagement of the developing unit  700  with the stripping unit  300 , the washing unit  400  and the drying unit  500 . The control unit  600  can also provide some flexibility according to the use of the developing unit  700  and maintenance.  
         [0048]    [0048]FIG. 5 is a block diagram that shows the layout of the various components of the photoresist stripping apparatus and the operating sequence for conducting the stripping operation according to one embodiment of the invention. The transporting unit  200  has a function similar to the embodiment shown in FIG. 1. As shown in FIG. 5, the OLED panels  10  (not shown) is transported to a n-butyl acetate (NBA) stripping bath  510  to carry out a first NBA treatment. The OLED panels  10  are next transferred to a second NBA stripping bath  520 . The purpose of having a second NBA bath is to remove any possible residual photoresist that still clings to the OLED panel surface.  
         [0049]    The OLED panels  10  are moved to an isopropyl alcohol (IPA) stripping bath  530 . The IPA stripping bath  530  is positioned after the second NBA stripping bath  520 . The IPA bath  530  not only removes any residual photoresist clinging on the OLED panel surface, but also removes any residual n-butyl acetate on the surface of the OLED panels  10 .  
         [0050]    The OLED panels  10  are moved by the transporting unit  200  to a washing bath  540  so that the OLED panels  10  are washed by de-ionized water. After a preliminary washing step, the OLED panels  10  are moved to a second washing bath  550  to carry out another washing with de-ionized water so that any residual isopropyl alcohol is removed.  
         [0051]    Finally, the OLED panels  10  is transferred to a blow drying unit  560  where an air knife drying method is used, thereby completing the process of stripping a photoresist layer off each OLED panel  10 .  
         [0052]    [0052]FIG. 6 is a block diagram that shows the layout of the various components of the photoresist stripping apparatus and the operating sequence for conducting the stripping operation according to another embodiment of the invention. The transporting unit  200  has a function similar to the embodiment shown in FIG. 1. As shown in FIG. 6, an OLED panel  20  (not shown) is transported to an n-butyl acetate (NBA) stripping bath  810  to carry out a NBA treatment for removing photoresist material. Meanwhile, another OLED panel  30  (not shown) is transported to another n-butyl acetate (NBA) stripping bath  820  to carry out a NBA treatment for removing photoresist material. The first NBA stripping bath  810  and the second NBA stripping bath  820  are positioned in parallel. The main advantage of having two or more NBA stripping baths arranged in parallel is that more OLED panels  10  can be treated at the same time.  
         [0053]    After the NBA treatment, the OLED panel  20  is transferred to an isopropyl alcohol (IPA) stripping bath  830 . Meanwhile, another OLED panel  40  (not shown) is passed into the NBA stripping bath  810  to carry out NBA treatment. The IPA stripping bath  830  is positioned after the NBA stripping baths  810  and  820 . The IPA stripping bath  830  is responsible for removing residual photoresist material as well as any residual n-butyl acetate clinging to the surface of the OLED panels.  
         [0054]    The OLED panel  20  is next transferred to a washing bath  840  and cleaned by spraying de-ionized water. Meanwhile, the OLED panel  30  is transferred to the IPA stripping bath  830  and another OLED panel  50  (not shown) is transferred to the NBA stripping bath  820  for n-butyl acetate treatment.  
         [0055]    After passing through the washing bath  840 , the OLED panel  20  is transferred to another washing bath  850  for further cleaning using de-ionized water. Finally, the OLED panel  20  is dried in a drying unit  860  that employs an air knife drying method. After the series of steps, the photoresist layer on the OLED panel  20  is completely removed.  
         [0056]    [0056]FIG. 7 is a block diagram that shows the layout of the various components of the photoresist stripping apparatus and the operating sequence for conducting the stripping operation according to one another embodiment of the invention. The transporting unit  200  has a function similar to the embodiment shown in FIG. 1. As shown in FIG. 7, an OLED panel  60  (not shown) is transported to an n-butyl acetate (NBA) stripping bath  910  to carry out a NBA treatment for removing photoresist material. Meanwhile, another OLED panel  70  (not shown) is transported to another n-butyl acetate (NBA) stripping bath  920  to carry out a NBA treatment for removing photoresist material. The first NBA stripping bath  910  and the second NBA stripping bath  920  are positioned in parallel. After a first NBA treatment, the OLED panel  60  is transferred to another NBA stripping bath  930 . At the same time, another OLED panel  80  (not shown) is transferred to the NBA stripping bath  910  to perform an initial NBA treatment. The NBA stripping bath  930  and the NBA stripping bath  910  are serially connected. By introducing a second NBA treatment, a complete removal of the photoresist material from the OLED panels is ensured.  
         [0057]    After the second NBA treatment in the NBA stripping bath  930 , the OLED panel  60  is transferred to an isopropyl alcohol (IPA) stripping bath  940 . Meanwhile, the OLED panel  70  is transferred to the NBA stripping bath  930  and another OLED panel (not shown) is transferred to the NBA stripping bath  920  to carry out initial NBA treatment. The IPA stripping bath  940  is positioned after the NBA stripping bath  930 . The IPA stripping bath  940  is responsible for removing residual photoresist material as well as any n-butyl acetate clinging to the surface of the OLED panels.  
         [0058]    The main advantage of having two or more NBA stripping baths arranged in parallel is that more OLED panel can be treated at the same time. Note that the parallel-serial arrangement is not limited to three NBA stripping baths. In fact, any number of NBA baths can be configured in a parallel-serial arrangement.  
         [0059]    After passing the IPA stripping bath  940 , the OLED panel  60  is transferred to a washing bath  950  for cleaning using de-ionized water. Meanwhile, the OLED panel  70  is transferred to the IPA stripping bath  940  and the OLED panel  80  is transferred to the NBA stripping bath  930  for n-butyl acetate treatment.  
         [0060]    The OLED panel  60  is next moved from the washing bath  950  to another washing bath  960  to carry out another washing with de-ionized water. Finally, the OLED panel  60  is dried in a drying unit  970  that employs an air knife drying method. After the series of steps, the photoresist layer on the OLED panel  60  is completely removed.  
         [0061]    Accordingly, the invention provides a method of photoresist stripping for an organic light-emitting display (OLED) panel. In one embodiment of the invention, the method may be described by referring to any one of FIG. 5, FIG. 6 or FIG. 7. However, the scope of the claims of the method should not be limited to the embodiments or the invention or the drawings. The method of the invention includes, for example but not limited to, the following steps. Referring to FIG. 5, at least one n-butyl acetate treatment of the OLED panel is provided by, for example but not limited to, a n-butyl acetate stripping bath such as bath  510 . Then, at least one isopropyl alcohol treatment of the OLED panel is provided by, for example but not limited to, an isopropyl alcohol cleaning bath such as bath  530 . Next, the surface of the OLED panel is cleaned with de-ionized water one or more times by, for example but not limited to, a washing bath such as bath  540 . Thereafter, any de-ionized water is removed from the surface of the OLED panel using an air knife by, for example but not limited to, a blow-drying unit such as unit  560 . As shown in FIG. 5, although there are two n-butyl acetate stripping baths  510  and  520 , however, the OLED panel may be treated by n-butyl acetate once or more times. Moreover, although there are two washing baths  510  and  520 , however, the OLED panel may be cleaned by de-ionized water once or more times.  
         [0062]    In one embodiment of the method of the invention, the treatment of the OLED panel with n-butyl acetate may be performed by spraying the liquid onto the OLED panel surface or immersing the entire OLED panel into a pool of the liquid.  
         [0063]    In one embodiment of the method of the invention, the treatment of the OLED panel with n-butyl acetate may be performed by immersing the entire OLED panel into a pool of the liquid.  
         [0064]    In one embodiment of the method of the invention, the treatment of the OLED panel with n-butyl acetate may be performed by spraying the liquid onto the OLED panel surface.  
         [0065]    In one embodiment of the method of the invention, the treatment of the OLED panel with n-butyl acetate may be performed by a combination of spraying the liquid onto the OLED panel surface and immersing the entire OLED panel into a pool of the liquid.  
         [0066]    In one embodiment of the method of the invention, the treatment of the OLED panel with isopropyl alcohol may be performed by immersing the entire OLED panel into a pool of the liquid.  
         [0067]    In one embodiment of the method of the invention, the cleaning of the OLED panel with de-ionized water may be performed by spraying the liquid onto the OLED panel surface.  
         [0068]    In one embodiment of the method of the invention, the step of using n-butyl acetate to strip photoresist material from the surface of the OLED panel may further includes shuttling the OLED panel inside the n-butyl acetate reaction chamber.  
         [0069]    The invention also provides an apparatus of photoresist stripping for an organic light-emitting display (OLED) panel. The apparatus includes, for example but not limited to, a stripping unit, a washing unit, a blow-drying unit, a transporting unit and a control unit. The stripping unit provides at least one n-butyl acetate treatment of the OLED panel and/or at least one isopropyl alcohol treatment of the OLED panel to remove photoresist on the surface of the OLED panel. The washing unit is provided for spraying a cleaning solution to remove n-butyl acetate and/or isopropyl alcohol on the surface of the OLED panel. The blow-drying unit is provided for drying the OLED panel. The transporting unit is provided for continuously transferring OLED panels to the stripping unit, the washing unit and the blow-drying unit. The control unit is provided for controlling the sequence and timing of transfer of OLED panels to each treatment unit.  
         [0070]    In one embodiment of the invention, the apparatus further includes a carrier unit for holding waiting OLED panels or providing a buffer region for holding OLED panel after photoresist development so that the OLED panels may be directly transferred to a subsequent module.  
         [0071]    In one embodiment of the invention, the apparatus further includes a downloading unit for holding photoresist stripped OLED panels or providing a buffer region for holding photoresist stripped OLED panels so that the photoresist stripped OLED panels may be directly transferred to a high-temperature baking module.  
         [0072]    In one embodiment of the invention, the stripping unit includes at least one n-butyl stripping baths and at least one isopropyl alcohol stripping baths.  
         [0073]    In one embodiment of the invention, the n-butyl acetate stripping baths are positioned to form a serial configuration, a parallel configuration or a mixture of bath.  
         [0074]    In one embodiment of the invention, the isopropyl alcohol stripping baths are positioned to form a serial configuration, a parallel configuration or a mixture of bath.  
         [0075]    In one embodiment of the invention, the isopropyl alcohol stripping baths are positioned behind the n-butyl acetate stripping baths.  
         [0076]    In one embodiment of the invention, the washing unit includes a plurality of washing baths. Furthermore, the cleaning baths are positioned serially.  
         [0077]    The invention further provides an apparatus of photoresist stripping for an organic light-emitting display (OLED) panel. The apparatus includes, for example but not limited to, a stripping unit, a washing unit, and a blow-drying unit. The stripping unit provides at least one n-butyl acetate treatment of the OLED panel and/or at least one isopropyl alcohol treatment of the OLED panel to remove photoresist on the surface of the OLED panel. The washing unit is provided for spraying a cleaning solution to remove n-butyl acetate and/or isopropyl alcohol on the surface of the OLED panel. The blow-drying unit is provided for drying the OLED panel.  
         [0078]    In one embodiment of the invention, the apparatus further includes a transporting unit for continuously transferring OLED panels to the stripping unit, the washing unit and the blow-drying unit.  
         [0079]    In one embodiment of the invention, the apparatus further includes a control unit for controlling the sequence and timing of transfer of OLED panels to each treatment unit.  
         [0080]    In brief, this invention provides a photoresist stripping device and a corresponding photoresist stripping method. The apparatus and the corresponding method not only can remove a photoresist layer from the surface of an OLED panel with high cleanliness, but can also strip photoresist layer from OLED panels having various sizes en-mass in a continuous process. [0078] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.