Patent Publication Number: US-7591900-B2

Title: Nozzle for supplying treatment liquid and substrate treating apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application claims priority under 35 USC 119 based on Japanese patent application No. 2005-181631, filed 23 Aug. 2005. The entire content of the priority Japanese application is incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a nozzle for supplying a treatment liquid such as a cleaning liquid or a developing liquid to a substrate such as a glass substrate or a semiconductor wafer, and a substrate treating apparatus provided with the nozzle for supplying a treatment liquid. 
   2. Description of Prior Art 
   Large-screen and high-quality TFT-LCDs (Liquid Crystal Display device) are needed more and more in the fields of personal computers, televisions, mobile phones, and so on. One of the manufacturing steps for the LCD (Liquid Crystal Display) is a TFT array step. However, if there are fine particles (such as waste, dust, foreign materials) on the surface of the glass substrate in this step, the yield will deteriorate. 
   Thus, according to Patent Document 1, there has been known a method for removing fine particles from a surface of a glass substrate by cleaning. In the method of Patent Document 1, as shown in  FIG. 6 , fine particles adhering to the surface of the glass substrate are lifted up by ultrasonic waves applied from the lower surface of the glass substrate, and the lifted particles are washed away with ionized water with an adjustable flow. 
   Patent Document 1: Patent Application Publication No. 2005-013960 
   However, since this method requires an ultrasonic wave generating device, it is expected that the cost will be high. Also, if the size of a substrate is increased, ultrasonic waves cover only a small area, making it difficult to perform uniform cleaning to the substrate. 
   The present invention was made to solve the above-mentioned problems, and the object of the present invention is to provide a nozzle for supplying a treatment liquid which makes it possible to perform uniform cleaning to a surface of a substrate even in a case where the size of a substrate is large, and to provide a substrate treating apparatus provided with the nozzle for supplying a treatment liquid. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided a nozzle for supplying a treatment liquid comprising two parts bonded to each other, a slit-shaped ejection hole which opens to the lower end of the bonded two parts, and a supply passage for a treatment liquid which leads to the slit-shaped ejection hole, wherein projections are provided on the abutting surface of at least one of the two parts so as to divide the treatment liquid flowing downward through the supply passage to the left and right. 
   In the nozzle for supplying a treatment liquid according to the present invention, the treatment liquid flowing downward is divided by the projections provided in the supply passage. Since division of the treatment liquid is not uniform between the left and right sides, one of the sides has a larger flow rate than the other. The lower pressure on the side where the flow rate is lower attracts the larger flow causing the direction of flow to swing to the side with the lower pressure. 
   While the treatment liquid is ejected from the nozzle, the above-mentioned phenomenon occurs repeatedly. Therefore, it is possible to apply the treatment liquid flowing downward from the slit-shaped ejection hole onto the substrate with the direction of flow of the treatment liquid continuously swinging from left and right. 
   Therefore, when a cleaning liquid as the treatment liquid is allowed to flow downward in an actual substrate treating apparatus provided with the above-mentioned nozzle for supplying a treatment liquid, it is possible to perform uniform cleaning to the surface of the substrate. 
   In the substrate treating apparatus according to the present invention, the above-mentioned nozzle for supplying a treatment liquid is positioned above a conveying path of the nozzle, and the width direction of the substrate and the slit-shaped ejection hole of the nozzle for supplying a treatment liquid are positioned in parallel. 
   In the substrate treating apparatus according to the present invention, since the above-mentioned nozzle for supplying a treatment liquid is positioned above the conveying path, and the width direction of the substrate and the slit-shaped ejection hole of the nozzle for supplying a treatment liquid are positioned in parallel, it is possible to perform uniform cleaning to a surface of the substrate, and improve the cleaning efficiency with respect to particles on the substrate when a cleaning liquid is used as the treatment liquid. 
   With the nozzle for supplying a treatment liquid according to the present invention, it is possible to eject a treatment liquid in a predetermined cycle with the direction of flow of the treatment liquid swinging left and right in the longitudinal direction of the slit-shaped ejection hole. 
   With the substrate treating apparatus according to the present invention provided with the above-mentioned nozzle for supplying a treatment liquid, it is possible to perform uniform cleaning to a substrate and improve the cleaning efficiency. 
   Therefore, it is possible to provide a nozzle for supplying a treatment liquid suitable for cleaning treatment and developing treatment even in a case of a large-sized substrate. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a substrate treating apparatus provided with a nozzle for supplying a treatment liquid according to an embodiment of the present invention; 
       FIG. 2  shows an abutting surface of one of two abutting parts of the nozzle of  FIG.1 ; 
       FIGS. 3(   a ) and ( b ) are enlarged views of a main part of  FIG. 2 ; 
       FIGS. 4(   a ) and ( b ) are views explaining the swinging direction of a treatment liquid ejected from the nozzle; 
       FIG. 5  is a view explaining the swinging direction of a treatment liquid ejected from the nozzle with respect to the conveyed substrate; and 
       FIG. 6  shows a conventional example of a cleaning method. 
   

   DETAILED DESCRIPTION OF PRESENT EXEMPLARY EMBODIMENTS 
   Hereinafter, embodiments according to the present invention will be explained with respect to a case where the present invention is applied to a nozzle for supplying a cleaning liquid in which the cleaning liquid is ejected onto a substrate, and also applied to a substrate cleaning apparatus provided with the nozzle. 
   As shown in  FIG. 1 , a substrate cleaning apparatus  15  according to an embodiment of the present invention has a plurality of rollers  1  for conveying a glass substrate G, and a nozzle  2  for supplying a cleaning liquid which is provided perpendicularly to the glass substrate G above the rollers  1 . 
   In the substrate cleaning apparatus  15  having the above-mentioned structure, when the glass substrate G is conveyed, the cleaning liquid supplied from the nozzle  2  toward the glass substrate G flows in the relatively reverse direction to the direction of conveying the glass substrate G. 
   Also, the nozzle  2  for supplying a cleaning liquid can be moved without conveying the glass substrate G. 
   As shown in  FIGS. 1-3 , the nozzle  2  for supplying a cleaning liquid has a structure in which a nozzle part  2   a  and a nozzle part  2   b  are bonded to each other. A passage  3  for supplying a cleaning liquid is formed in conjunction with the abutting surfaces of the parts. The passage  3  for supplying a cleaning liquid is comprised of a horizontal passage  4  which extends in a lateral direction in the upper area of the nozzle, and a plurality of vertical passages  5  which are distributed from the horizontal passage  4  downward. 
   Supply holes  7  are provided at a predetermined interval in the horizontal passage  4 , and a cleaning liquid is supplied from the outside into the horizontal passage  4  through the supply holes  7 . A narrow connecting passage  6  is provided between the horizontal passage  4  and each of the vertical passages  5 . 
   Also, according to the present embodiment, projections are provided on the abutting surface of at least one of the two nozzle parts so as to divide a treatment liquid flowing downward through the supply passage to the left and right. 
   For example, in the vertical passages  5  distributed from the horizontal passage  4  downward in the abutting surface of the nozzle part  2   a , projections (upper projections)  8  are provided in the upper area of the vertical passages  5 , projections (intermediate projections)  9  are provided in the intermediate area of the vertical passages  5 , and projections (lower projections)  10  are provided in the lower area of the vertical passages  5 . 
   The intermediate projections  9  are provided so as to be a pair oriented next to each other horizontally. Air-supply openings  11  are provided between the intermediate projections  9  and the upper projections  8 , so that clean dried air can flow through the openings  11 . The upper, intermediate and lower projections  8 ,  9  and  10  are provided at a predetermined interval. A passageway  12  and a passageway  13  defined on the left and right of the lower projection  10 , are reduced by side bulges  16 . 
   In this way, the nozzle  2  for supplying a cleaning liquid is constructed by bonding the abutting surface  2   a  on which the projections  8 ,  9  and  10  are formed, and the abutting surface  2   b  on which no projections are formed. 
   Next, the flow of the cleaning liquid which is supplied to the horizontal passage  4  and ejected onto a surface of the glass substrate G will be explained in detail. 
   First, the horizontal passage  4  is filled with a cleaning liquid supplied from the supply holes  7 , and the cleaning liquid enters the vertical passages  5  via the narrow passages  6 . 
   The cleaning liquid is divided into left and right by the upper projections  8 . Air (preferably, dried cool air) is supplied from the air-supply openings  11  into the cleaning liquid left and right flows thereby increasing the flow velocity of the cleaning liquid. 
   The cleaning liquid containing the air is divided into left and right flows again by the intermediate projections  9  and  9 , flows through the passageway  12  and the passageway  13  formed on the left and right of the lower projections  10 , and is ejected from a slit-shaped ejection hole  14  formed at the lower end of the nozzle toward the glass substrate G. 
   Next, the cleaning liquid flow through the passageway  12  and the passageway  13  will be described. 
   The direction and flow rate of the cleaning liquid flowing through the passageway  12  and the passageway  13  are controlled by the shape of the upper projections  8 , the intermediate projections  9 , and the lower projections  10 . Therefore, even if the cross-sectional area of the passageway  12  and the passageway  13  is adjusted to be equal, imbalance still occurs. 
   For example, the flow rate in the passageway  12  is larger than the flow rate in the passageway  13  in  FIG. 3   a , and the cleaning liquid is directed to the left (see arrow X). Since the pressure in the passageway  13  is lower than the pressure in the passageway  12  in this state, the flow rate in the passageway  13  will increase as flow is attracted toward the region with the lower pressure. Consequently, the cleaning liquid is directed to the right as shown in  FIG. 3   b  (see arrow Y). 
   Since this phenomenon repeatedly occurs, the cleaning liquid ejected from the nozzle  2  for supplying a cleaning liquid toward the glass substrate G is alternately in a state of  FIG. 4   a  and in a state of  FIG. 4   b . In other words, the cleaning liquid ejected from the nozzle  2  for supplying a cleaning liquid toward the glass substrate G swings left and right along the slit-shaped ejection hole  14 . 
   The glass substrate G is conveyed in a direction perpendicular to the longitudinal direction of the slit-shaped ejection hole  14 . Therefore, the cleaning liquid is ejected in a reverse direction to the conveying direction of the glass substrate G while swinging to the left and right in directions substantially parallel to the slit-shaped ejection hole (see arrow C). In this way, fine particles adhering to the surface of the glass substrate G can be removed effectively. 
   More specifically, if the cleaning liquid is just ejected from the slit-shaped ejection hole  14  onto the surface of the glass substrate G, cleaning is performed only by force of the flow of the cleaning liquid (see arrow B) along the same axis (Y-axis) as the conveying direction of the glass substrate G (see arrow A) as shown in  FIG. 5 . 
   On the other hand, if the cleaning apparatus  15  according to the present embodiment is used, it is possible to perform cleaning by force of the flow of the cleaning liquid (see arrow C) along X-axis which intersects the conveying direction of the glass substrate G (see arrow A) as shown in  FIG. 5 . 
   In this way, the cleaning efficiency can be greatly improved by the force of the cleaning liquid which uniformly intersects the conveying direction of the glass substrate G compared to the case where cleaning is performed only by the force of the flow of the cleaning liquid (see arrow B) along the same axis (Y-axis). 
   As mentioned in the above, according to the present embodiment, it is possible to allow the treatment liquid ejected from the nozzle  2  for supplying a cleaning liquid onto the glass substrate G to swing left and right along the slit-shaped ejection hole  14 . 
   With this, when the cleaning liquid as a treatment liquid is allowed to flow downward in the substrate cleaning apparatus  15  provided with the nozzle  2  for supplying a cleaning liquid, it is possible to further improve the effect of cleaning (removing) particles adhering to the substrate by swinging the cleaning liquid to the left and right compared to a conventional technique in which ultrasonic vibration is applied from the lower surface of the substrate. 
   Also, even in a case of a large substrate, it is possible to perform uniform cleaning to particles adhering to the substrate by swinging the cleaning liquid to the left and right and, unlike when ultrasonic waves are used, all areas will be cleaned uniformly. 
   Furthermore, it is possible to reduce the cost because there is no need of an ultrasonic generator. 
   In addition, according to the present embodiment, the air-supply openings  11  are provided in the course of the vertical passages  5 , and air is supplied from the air-supply openings  11  at the time of ejecting the cleaning liquid onto the glass substrate G. With this, the flow rate of the cleaning liquid can be increased and the cleaning effect can be greatly improved. 
   In the above-mentioned embodiment, the projections provided in the vertical passages  5  are comprised of an upper one, intermediate ones and a lower one as shown in  FIG. 3 . However, the arrangement of the projections is not limited to this, and various embodiments are possible. 
   Also, in the above-mentioned embodiment, the projections are provided in the abutting surface  2   a . However, the projections may be provided in both of the abutting surface  2   a  and the abutting surface  2   b.    
   Also, in the above-mentioned embodiment, a cleaning liquid is used as the method for removing particles from the substrate. However, it is possible to perform the method by using air alone without using a cleaning liquid. 
   In such a case, air may be introduced from the supply holes  7  of the horizontal passage  4  in the nozzle  2  for supplying a cleaning liquid. 
   With this, air can be ejected onto the surface of the glass substrate G in the same manner as the case of the cleaning liquid so as to remove fine particles from the glass substrate G. 
   Incidentally, it is possible to improve the efficiency of cleaning particles by using dried air, ozone air, gas, or the like. It is also possible to achieve additional effectiveness by eliminating static charge by using ionized air. 
   Also, in the above-mentioned embodiment, the nozzle  2  for supplying a cleaning liquid is provided perpendicularly. However, the structure of the nozzle  2  for supplying a cleaning liquid is not limited to this, and the nozzle  2  for supplying a cleaning liquid may be provided obliquely in a state where the upper portion thereof is put forward, for example. 
   With this, the cleaning liquid can flow smoothly in a reverse direction to the conveying direction of the substrate G. 
   In the above-mentioned embodiment, air is mixed into the cleaning liquid so as to increase the flow velocity. However, it is not essential to mix air. It is still possible to eject the cleaning liquid from the nozzle  2  onto the glass substrate G in a state of swinging the cleaning liquid left and right along the slit-shaped ejection hole  14  so as to improve the effect of cleaning particles adhering to the substrate compared to a conventional technique in which ultrasonic vibration is applied from the lower surface of the substrate. 
   Further, by increasing the flow rate of the cleaning liquid, the swinging velocity of the cleaning liquid can be increased, and the cleaning efficiency can be improved. 
   In the above-mentioned embodiment, a cleaning liquid is used as the treatment liquid. However, a developing liquid can be used depending on the purpose. In this case, it is possible to perform uniform developing treatment to a film formed on a substrate. 
   Incidentally, the present invention is not limited to the above-mentioned embodiments, and various structures are possible within the scope of the present invention.