Abstract:
A pure developing solution is discharged from a discharge port of a developing solution supply nozzle. A developing solution with reaction in progress flows from the center of a wafer by centrifugal force. The amount of the developing solution with reaction in progress mixing with the pure developing solution increases as it gets farther away from the wafer center, causing unequal development. To prevent such a problem, the developing solution supply nozzle is divided into a plurality of areas. The nozzle is composed so that the amount of the developing solution discharged from the discharge ports of each area gradually decreases as the areas approach the rotating center of the wafer. Thus, uniform development is achieved.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a developing apparatus for developing an object to be processed (hereinafter referred to as a ‘target object’) such as a semiconductor wafer. 
     2. Description of the Related Art 
     In a photo-resist processing step in manufacturing a semiconductor, for example, a resist film is formed by coating a resist solution on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as a ‘wafer’). A predetermined pattern is then exposed upon the wafer, and the wafer is developed with a developing solution. A developing apparatus has been used to perform such developing process. 
     Generally, a developing apparatus has a spin chuck and a nozzle for supplying a developing solution. The spin chuck rotates a wafer while holding it by vacuum. The developing solution supply nozzle moves to a predetermined position above the spin chuck. The supply nozzle is longer than the diameter of the wafer and has a header shape. Discharge ports are arranged along a line at the bottom of the supply nozzle. 
     In order to supply the developing solution upon the wafer using such developing solution supply nozzle, the supply nozzle must first move to a predetermined position above the wafer held by the spin chuck, a position overlapping with the diameter of the wafer. The developing solution is then supplied to the developing solution supply nozzle. The supply nozzle discharges the developing solution from the discharge ports upon the wafer, while the wafer is rotated for more than a half turn so that the developing solution is equally supplied to the entire surface of the wafer. 
     SUMMARY OF THE INVENTION 
     In such a conventional developing apparatus, nearly pure developing solution not yet starting to react is constantly supplied to the center of the wafer. However, the developing solution with reaction in progress flows outward from the wafer center by centrifugal force. Such developing solution mixes increasingly with the pure developing solution discharged from the discharge ports, as it gets farther away from the wafer center. Thus, development becomes unequal. In other words, the development progress slows down as it gets farther away from the wafer center. Therefore, the line width is finer near the wafer center, and wider near the wafer edge. 
     The present invention aims to solve the above-mentioned problem. Its object is to provide a developing apparatus which performs uniform development. 
     To solve the above-described problem, a first aspect of the present invention is a developing apparatus having a means for rotating while holding a target object, and a nozzle divided into a plurality of areas with discharge ports arranged along a line for discharging a developing solution on the surface of the target object held and rotating. The developing apparatus also has a means for controlling the discharge amount of the developing solution so that the amount of the developing solution discharged from the discharge port disposed in an area near a rotating center of the target object is less compared to the amount discharged from the ports in other areas. 
     The present invention has a nozzle divided into a plurality of areas and discharging less developing solution from the area near the rotating center of the target object as compared with other areas. Therefore, the ratio of a pure developing solution supplied near the rotating center of the target object and a pure developing solution supplied around the periphery of the target object is approximately the same. Thus, unequal development may be prevented. 
     A second aspect of the present invention is a developing apparatus having a means for rotating while holding a target object, and a nozzle divided into a plurality of areas with discharge ports arranged along a line for discharging a developing solution on the surface of the target object held and rotating. The developing apparatus also has a means for controlling an amount of the developing solution discharged from the discharge ports in each area and disposed midway of a discharge path for discharging the developing solution. 
     The present invention has a nozzle divided into a plurality of areas and a means for controlling the discharge amount of the developing solution discharged from the discharge ports of each area. The nozzle and the controlling means are disposed integrally. Thereby, the discharge time and amount of the developing solution discharged from each area is controlled more accurately. The number of pipes for sending the developing solution to the nozzle may also be decreased. 
     These and other objects and profits of the invention can be easily defined by the following explanations and the accompanied drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a coating and developing apparatus concerning a preferred embodiment of the present invention; 
     FIG. 2 is a front view of the coating and developing apparatus shown in FIG. 1; 
     FIG. 3 is a rear view of the coating and developing apparatus shown in FIG. 1; 
     FIG. 4 is a front view showing the composition of a developing unit shown in FIG. 1; 
     FIG. 5 is a plan view showing the composition of a developing unit shown in FIG. 4; 
     FIG. 6 is a perspective view showing the composition of a developing solution supply nozzle shown in FIG. 4; 
     FIG. 7 is a bottom view showing the composition of a developing solution supply nozzle shown in FIG. 6; 
     FIG. 8 is a drawing showing an example of the timing for discharging a developing solution from the discharge ports in each area of the developing solution supply nozzle shown in FIG. 6; 
     FIG. 9 is a drawing showing an example of the amount of developing solution discharged from the discharge ports in each area of the developing solution supply nozzle shown in FIG. 6; 
     FIG. 10 is a drawing to explain the problem arising when the developing solution supply nozzle is divided into a plurality of areas as the case of the present invention; 
     FIG. 11 is a bottom view showing the composition of a developing solution supply nozzle concerning another embodiment; 
     FIG. 12 is a bottom view showing the composition of a developing solution supply nozzle concerning another embodiment; 
     FIG. 13 is a front view showing the composition of a developing solution supply nozzle concerning still another embodiment; 
     FIG. 14 is a schematic view showing the composition of a developing solution supply nozzle concerning still another embodiment; 
     FIG. 15 is a schematic view showing an example of the actual timing for supplying the developing solution using a developing solution supply nozzle shown in FIG. 14; and 
     FIG. 16 is a bottom view of a developing solution supply nozzle showing the composition when changing the size of the discharge ports. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment according to the present invention will be explained with reference to the accompanied drawings. 
     FIG. 1 is a plan view, FIG. 2 is a front view, FIG. 3 is a rear view of the coating and developing apparatus concerning an embodiment of the present invention. 
     As shown in FIGS. 1 and 3, this coating and developing unit  1  is composed of a cassette station  10 , a process station  11  and an interface section  12 , connected integrally. In the cassette station  10 , a plurality of wafers W (25, for example) is introduced into the coating and developing unit  1  from outside in units of cassettes C, and then transferred out from the coating and developing unit  1 . Wafers W are also transferred into and out of the cassettes C. In the process station  11 , various kinds of single-wafer processing units are disposed multi-tiered in a predetermined position. These processing units perform a predetermined process upon the wafer W one by one during the coating and developing steps. In the interface section  12 , the wafers W are delivered to and from an exposure unit  13  disposed next to the coating and developing unit  1 . 
     In the cassette station  10 , as shown in FIG. 1, a plurality of cassettes C (four, for example) is mounted on a cassette mounting table  20  in the position of a positioning projection  20   a . The cassettes C are mounted along a line in the X-direction (the up and down direction in FIG.  1 ). The opening of the cassettes C, through which the wafers W are taken in and out, face the process station  11 . A wafer transfer unit  21  moves in the cassettes C arrangement direction (X-direction). It also moves in the wafers W arrangement direction (Z-direction; vertical direction), the direction in which the wafers W stored inside the cassettes C are arranged. The wafer transfer unit  21  moves freely along a transfer path  21   a  and makes access selectively to each cassette C. 
     The wafer transfer unit  21  rotates freely in the θ direction and makes access to an alignment unit (ALIM) and an extension unit (EXT). The alignment unit and the extension unit belong to a multi-tiered units section of a third processing unit group G 3  on the process station  11  side. 
     In the process station  11  as shown in FIG. 1, a vertical-transfer type transfer unit  22  is disposed in the center. Around it, two or more processing units are disposed multi-tiered to form processing unit groups. In such a coating and developing unit  1 , five processing unit groups G 1 , G 2 , G 3 , G 4  and G 5  may be disposed. A first processing unit group G 1  and a second group G 2  are disposed on the front side of the system. A third processing unit group G 3  is disposed next to the cassette station  10 . A fourth processing unit group G 4  is disposed next to the interface section  12 . And a fifth processing unit group G 5  shown by a broken line can be disposed on the rear side. The transfer unit  22  rotates freely in the θ direction and moves in the Z-direction in order to deliver wafers W to and from various processing units. 
     In the first processing unit group G 1  as shown in FIG. 2, two spinner-type processing units, such as a resist coating unit (COT) and a developing unit (DEV), are two-tiered from the bottom in order. These units perform a predetermined process with the wafers W mounted on a spin chuck inside a cup CP. In the second processing unit group G 2  as in the first processing unit group G 1 , two spinner-type processing units, such as a resist coating unit (COT) and a developing unit (DEV), are two-tiered from the bottom in order. 
     In the upper portion of the coating and developing unit  1  as shown in FIG. 2, high-efficiency filters  23 , such as UPLA filters, are disposed in each of the above-mentioned zones (the cassette station  10 , the process station  11 , the interface section  12 ). The high-efficiency filter  23  catches and removes particles and organic materials from the air supplied from the upper-stream side of the filter  23 . Thus, through the high-efficiency filter  23 , a clean down-flow of air is supplied from above in the direction of the solid arrow or the dotted arrow in FIG.  2 . The clean air flows to the cassette mounting table  20 , the transfer path  21   a  of the wafer transfer unit  21 , the first processing unit group G 1 , the second group G 2 , the third through fifth processing unit groups G 3 , G 4  and G 5  which will be mentioned later, and the interface section. 
     In the third processing unit group G 3  as shown in FIG. 3, eight oven-type processing units are multi-tiered, performing a predetermined process with the wafers W mounted upon the mounting table. The units are, for example, a cooling unit (COL) for cooling the wafer W, an adhesion unit (AD) for performing a hydrophobic process to improve the fixity of the resist, an alignment unit (ALIM) for positioning the wafer W, an extension unit (EXT), two pre-baking units (PREBAKE) for heating before exposure and two post-baking units (POBAKE), from the bottom in order. 
     Similarly, in the fourth processing unit group G 4  as shown in FIG. 3, eight oven-type processing units are multi-tiered, performing a predetermined process with the wafers W mounted upon the mounting table. The units are, for example, a cooling unit (COL) for cooling the wafer W, an extension/cooling unit (EXTCOL) which also cools, an extension unit (EXT), an adhesion unit (AD), two pre-baking units (PREBAKE) and two post-baking units (POBAKE), from the bottom in order. 
     Heat interference between the units can be kept at a minimum by disposing such units with low processing temperature as a cooling unit (COL) and an extension unit (EXTCOL) in the bottom and disposing such units with high processing temperature as a pre-baking unit (PREBAKE), a post-baking unit (POBAKE) and an adhesion unit (AD) on the top. 
     As shown in FIG. 1, the interface section  12  has the same size as the aforementioned process station in the depth direction (X-direction) but is smaller in the width direction. As shown in FIGS. 1 and 2, a movable pick-up cassette CR and a stable buffer cassette BR are two-tiered at the front side of the interface section  12 . A peripheral exposure unit  24  is disposed at the rear side. 
     A wafer transfer unit  25  is disposed in the center of the interface section  12 . The wafer transfer unit  25  moves in the X-direction and the Z-direction (vertical direction). It makes access to both cassettes CR and BR and to the peripheral exposure unit  24 . The wafer transfer unit  25  also moves freely in the θ direction and makes access to an extension unit (EXT). The extension unit belongs to the fourth processing unit group G 4  at the process station  11  side. The transfer unit  25  also makes access to the wafer delivery table (not shown) at the exposure unit side. 
     FIG. 4 is a front view and FIG. 5 is a plan view, both showing the composition of the above-mentioned developing unit (DEV). 
     As shown in FIGS. 4 and 5, a driving motor  32  is disposed at the center of a casing  31  of the developing unit (DEV). The rotation speed of the driving motor  32  may be changed freely with a controller  33  disposed separately outside the unit. A spin chuck  34  is disposed above the driving motor  32 . The spin chuck  34  rotates and moves up and down freely. The wafer W to be developed is held on top of the spin chuck  34  in a horizontal position. 
     A cylindrical cup  35  is disposed around the spin chuck  34 . The cup  35  made of resin or metal prevents the scattering of the developing solution or the washing liquid. The side wall of the cup  35  slants inward, the upper portion being narrower than the bottom portion. An opening  36  of the cup  35  has a diameter large enough to bring the wafer W downward inside the cup  35  in a horizontal position. 
     A bottom  37  of the  35  is slanted, and a drainpipe  38  is connected to its lowest portion. An exhaust pipe  39  for exhausting the air inside the cup  35  is connected on the opposite side of the drainpipe  38 , with the driving motor  32  in between. A circular wall  40  stands up from the bottom  37  of the cup  35 . A rectifying board  41  is disposed at the upper end of the circular wall  40 . The rectifying board  41  is disposed close to the underside of the wafer W held by the spin chuck  34 . The outer portion of the rectifying board  41  slants downward to the outside. 
     A developing solution supply nozzle  42  is disposed above at the side of the cup  35  inside the casing  31 . The developing solution supply nozzle  42  is connected to a developing solution supply unit  44  disposed outside the developing unit (DEV) through a developing solution supply pipe  43 . Ordinarily, when processing is not performed, the developing solution supply nozzle  44  is stored and waiting inside a sealed container  45 . A solvent filled inside the sealed container  45  prevents the evaporation and hardening of the developing solution. The developing solution supply nozzle  42  is held by a holding arm  47 . The holding arm  47  moves freely on a transfer rail  46  shown in FIG. 5, carrying the developing solution supply nozzle  42  back and forth in the direction shown by the arrow in FIG.  5 . 
     A washing liquid header  48  is disposed at the opposite side of the developing solution supply nozzle  42 , with the cup  35  in between. A washing nozzle  49  is disposed under the washing liquid header  48 . The washing liquid header  48  is connected to a pure water supply unit  51  disposed outside the developing unit (DEV) through a washing liquid supply pipe  50 . Pure water supplied from the pure water supply unit  51  is discharged from the washing nozzle  49 . In the same way as the developing solution supply nozzle  42 , the washing liquid header  48  is also held by the holding arm  47  and moves back and forth in the direction shown by the arrow in FIG.  5 . 
     In the developing unit (DEV) as shown in FIG. 4, a washing nozzle  52  is disposed separately to supply washing liquid such as pure water to the underside of the wafer W. The washing nozzle  52  is connected to a washing liquid supply unit  54  through a supply pipe  53 . So, the underside of the wafer W may also be washed with pure water. The pure water supply unit  51  may be used in common as the washing liquid supply unit  54 . 
     FIG. 6 is a perspective view and FIG. 7 is a bottom view, both showing the composition of the above-mentioned developing solution supply nozzle  42 . 
     As shown in FIGS. 6 and 7, the developing solution supply nozzle  42  has approximately the same diameter as the wafer W. A plurality of discharge ports  61  is disposed along a line under the developing solution supply nozzle  42 , to discharge the developing solution upon the surface of the wafer W. The developing solution supply nozzle  42  is divided into a plurality of areas, for example, into five areas  62   a ˜ 62   e . These areas  62   a ˜ 62   e  are symmetrical about the area  62   c  at the rotating center of the wafer W. In other words, the areas  62   b  and  62   d  are disposed symmetrical about the area  62   c  as the center, and the areas  62   a  and  62   e  are disposed symmetrical about the area  62   c  as the center. 
     A pipe  63  is disposed inside the developing solution supply nozzle  42 , in the direction of the diameter of the wafer W. The pipe  63  is connected to the pipe  43  whose other end is shown in FIG.  4 . The developing solution is supplied from the developing solution supply unit  44  through the pipe  43 . Pipes  64   a ˜ 64   e  branch from the pipe  63  into the areas  62   a ˜ 62   e . The branched pipes  64   a ˜ 64   e  are connected to the discharge ports  61  of the areas  62   a ˜ 62   e , respectively. 
     Air-operation valves  65   a ˜ 65   e  are inserted in the branched pipes  64   a ˜ 64   e , respectively. The air-operation valves  65   a ˜ 65   e  are disposed integrally with the developing solution nozzle  42 , as a means for controlling the amount of the developing solution discharged from the discharge ports  61  of the areas  62   a ˜ 62   e . The controller  33  shown in FIG. 4 controls the timing for opening/closing and the release amount of the air-operation valves  65   a ˜ 65   e . By composing the unit in the manner mentioned above, the present embodiment decreases the number of pipes and makes it possible to control the discharge timing from each area separately in units of 0.1 second. 
     The developing unit (DEV) according to an embodiment of the present invention is composed as mentioned above. After exposure, the wafer W is mounted on the spin chuck  34  inside the cup  35 . The developing solution supply nozzle  42  held by the holding arm  47  moves to a predetermined position above the wafer W, a position overlapping with the diameter of the wafer W. The developing solution supply nozzle  42  comes down, and the developing solution is supplied to the developing solution supply nozzle  42  from the developing solution supply unit  44  while the wafer W rotates slowly. 
     FIG. 8 is a drawing showing an example of the timing for discharging a developing solution from the discharge ports  61  in areas  62   a ˜ 62   e , when the developing solution is supplied as mentioned above. FIG. 9 is a drawing showing an example of such discharge amount. Such discharge timing and amount are controlled by the air-operation valves  65   a ˜ 65   e  as mentioned above, by controlling the timing for opening/closing and the narrowing of the flow amount. 
     FIG. 8 shows the discharge timing. The developing solution is first discharged from the discharge ports  61  of the areas  62   a  and  62   e  at the periphery of the wafer W. 0.2 seconds after that, the developing solution is discharged from the discharge ports  61  of the areas  62   b  and  62   d  in the middle of the wafer W. And 0.2 seconds after that, the developing solution is discharged from the discharge ports  61  of the area  62   c  at the center of the wafer W. The developing solution is discharged for two seconds from the discharge ports  61  of the areas  62   a  and  62   e , for 1.8 seconds from the discharge ports  61  of the areas  62   b  and  62   d , and for 1.6 seconds from the discharge ports  61  of the area  62   c . Needless to say, these timing show only an example. 
     FIG. 9 shows the discharge amount. A largest amount of the developing solution is discharged from the discharge ports  61  of the areas  62   a  and  62   e  at the periphery of the wafer W. Second largest amount of the developing solution is discharged from the discharge ports  61  of the areas  62   b  and  62   d  in the middle of the wafer W. And the least amount of the developing solution is discharged from the discharge ports  61  of the area  62   c  at the center of the wafer W. 
     In other words, in this embodiment, the discharge ports  61  of the area  62   c  at the rotating center of the wafer W discharge the least amount of developing solution among the areas  62   a ˜ 62   e . Therefore, the ratio of the pure developing solution supplied to the rotating center of the wafer W and the pure developing solution supplied to the middle or the periphery of the wafer W are the same. Thus, unequal development is prevented and the line width upon the wafer W becomes uniform. 
     Another embodiment of the invention will be explained next. 
     In the above-mentioned embodiment, as shown in FIG. 10, sometimes a “gap”  69  arises between the discharge ports  61  at the border of the adjoining areas ( 62   a  and  62   b , for example) when dividing the developing solution supply nozzle  42  into a plurality of areas  62   a ˜ 62   e . Such a “gap”  69  might cause unequal development. The following embodiment shown in FIGS. 11 and 12 aims to prevent this problem. 
     FIG. 11 is a bottom view showing the composition of the developing solution supply nozzle concerning another embodiment of the invention. 
     As shown in FIG. 11, a developing solution supply nozzle  70  has a plurality of areas  62   a ˜ 62   e  arranged alternately to prevent the above-mentioned “gap”. In such a composition, there will be a portion where the discharge ports  61  overlap between the adjoining areas. The size of the discharge ports in this overlapping portion should be made smaller than the other portion, for example, half. Or the density of the discharge ports  61  in such a portion could be made more sparse, for example, half. Thus, development uniformity improves. 
     FIG. 12 is bottom view showing the composition of the developing solution supply nozzle concerning another embodiment. 
     As shown in FIG. 12, a developing solution supply nozzle  71  has a plurality of areas  62   a ˜ 62   e  arranged like a stairway, with an overlapping portion of the discharge ports  61  between the adjoining areas. Thus, the above-mentioned “gap” is prevented. The composition may be the same as mentioned above concerning the overlapping portion of the discharge ports  61  between the adjoining areas. 
     FIG. 13 is a front view showing the composition of the developing solution supply nozzle concerning still another embodiment of the invention. 
     As shown in FIG. 13, a developing solution supply nozzle  72  is composed so that the areas  62   a ˜ 62   e  will have different heights. The discharge ports  61  of the areas  62   a  and  62   e  at the periphery of the wafer W may be disposed in the lowest position. The discharge ports  61  of the areas  62   b  and  62   d  in the middle of the wafer W are in the second lowest position. And the discharge ports  61  of the area  62   c  at the center of the wafer W are disposed at the highest position. By changing the height in such a way, the timing when the developing solution discharged from each area reaches the wafer W will be controlled. Thus, equal development is made possible. 
     FIG. 14 is a schematic view showing the composition of the developing solution supply nozzle concerning still another embodiment. 
     Similar to the above-mentioned embodiment, a developing solution supply nozzle  73  has a length approximately the same as the diameter of the wafer W. Beneath it, a plurality of discharge ports is disposed along a line for discharging a developing solution on the surface of the wafer W. In this embodiment, these discharge ports are divided into seven areas  73   a ˜ 73   g . These areas are symmetrical about the area  73   d  at the rotating center of the wafer W. 
     Two pipes  74  and  75  are connected to the areas  73   a ˜ 73   g  of the developing solution supply nozzle  73 . Electromagnetic valves  76  and  77  are inserted in these pipes  74  and  75 . And through a junction  43   a , the pipes  74  and  75  are connected to the developing solution supply pipe  43  connected to the developing solution supply unit  44  shown in FIG.  4 . 
     The pipe  74  is connected to the areas  73   a  and  73   g  at the periphery of the wafer W. The pipe  75  is connected to all the other areas  73   b ˜ 73   f  except the areas  73   a  and  73   g  at the wafer edge, including the area  73   d  at the center of the wafer W. To be more specific, the pipe  75  has branched pipes  75   a ˜ 75   e . These branched pipes  75   a ˜ 75   e  are connected to the areas  73   b ˜ 73   f , excluding the areas  73   a  and  73   g  at the wafer edge. Needle valves  75   f ˜ 75   j  are inserted in the branched pipes  75   a ˜ 75   e , respectively. And by adjusting the release amount of these needle valves  75   f ˜ 75   j , the amount of the developing solution supplied from the areas  73   b ˜ 73   f  can be adjusted minutely. 
     This embodiment is composed to supply the developing solution in two routes, from the areas  73   a  and  73   g  at the periphery of the wafer W and from the other areas  73   b ˜ 73   f . By opening and closing of the above-mentioned electromagnetic valves  76  and  77 , the discharge amount of the developing solution supplied from the areas  73   a  and  73   g  at the wafer edge and the discharge amount of the developing solution supplied from the other areas  73   b ˜ 73   f  are controlled separately. Therefore, by adequately adjusting the movement of the electromagnetic valves  76  and  77  as a means for controlling the discharge amount, the ratio of the pure developing solution supplied near the rotating center of the target object, wafer W, and the ratio of the pure developing solution supplied to the periphery of the target object can be controlled to be approximately the same. Thus, unequal development may be decreased. 
     Especially by separating the supply route of the developing solution to the areas  73   a  and  73   g  at the periphery of the wafer W where the line width tend to become wide, independent control is made easier and the development will be better balanced. 
     FIG. 15 is a schematic view showing an example of the actual timing for supplying the developing solution, using the developing solution supply nozzle  73  shown in FIG.  14 . First, as shown in FIG.  15 ( a ), all of the electromagnetic valves  76 ,  77 , and the needle valves  75   f ˜ 75   j  are kept open. The developing solution from the discharge ports in all the areas  73   a ˜ 73   g  are supplied for a predetermined time period. Next, as shown in FIG.  15 ( b ), the electromagnetic valve  77  is closed. The discharging from the areas  73   b ˜ 73   f  is stopped, the developing solution being supplied only from the areas  73   a  and  73   g  at the wafer edge for a predetermined time period. And as shown in FIG.  15 ( c ), the electromagnetic valve  77  is opened once more and the developing solution is supplied from the discharge ports in all the areas  73   a ˜ 73   g . The discharge time of pure developing solution from the areas  73   a  and  73   g  at the wafer edge becomes longer than the discharge time from the other areas  73   b ˜ 73   f . Thus, the ratio of pure developing solution supplied to the middle of the wafer W and to the periphery of the wafer W becomes equal. 
     Needless to say, the supply timing of the developing solution shown in FIG. 15 is only one example. The developing solution may be supplied from the discharge ports of all the areas  73   a ˜ 73   g  for a predetermined time period and then, the developing solution may be supplied only from the areas  73   a  and  73   g  at the periphery of the wafer W for a little longer. 
     As mentioned in the above embodiment, it is favorable to control the discharge amount to be the least from the discharge ports of the area  73   d  at the rotating center of the wafer W, the discharge amount increasing as the area approaches the wafer edge. The release amount of the needle valves  75   f ˜ 75   j  may be adjusted for controlling as such. 
     However, there still remains a discharge amount difference of the developing solution within the area  73   d  at the rotating center of the wafer W, between the center of the area  73   d  where the developing solution is constantly supplied to the same place and near the periphery of the area  73   d . Since the center of the area  73   d  is also the rotating center of the entire developing solution supply nozzle  73 , when a predetermined supply pressure is applied to the area  73   d  by adjusting the needle valve  75   h  and if the hole diameter of the discharge ports are all the same, the discharge amount will be large near the center of the area  73   d  and smaller near the edge. Therefore, the size of the discharge ports should not be the same in the area  73   d  at the rotating center of the wafer W. It is desirable to form the size of the discharge ports smaller near the rotating center so that less developing solution is discharged from the rotating center in the area  73   d.    
     FIG. 16 is a bottom view of the developing solution supply nozzle  73 , showing the composition when changing the size of the discharge ports. FIG.  16 ( a ) shows discharge ports  78  in circular shape. As shown in the drawing, the diameter of a discharge port  78   a  near the center of the area  73   d  is the smallest. Discharge ports  78   b  and  78   c  disposed at the edge have a larger hole diameter. FIG.  16 ( b ) shows discharge ports  79  shaped like a slit in the length direction of the discharge solution supply nozzle  73 . In the area  73   d  at the rotating center of the wafer W, the slit width of a discharge port  79   a  at the center is the narrowest. The slit width of the discharge ports  79   b  and  79   c  at the edge are wider. By forming the discharge ports in this way, even when the developing solution is supplied with a predetermined pressure in the area  73   d , less developing solution is discharged from the discharge ports  78   a  and  79   a  at the center, and more developing solution is discharged from the discharge ports  78   b ,  78   c ,  79   b  and  79   c  at the edge. Thus, the ratio of pure developing solution supplied within the area  73   d  will become even, preventing unequal line width in the area  73   d.    
     In this embodiment, the supply route of the developing solution to the areas  73   a  and  73   g  at the periphery of the wafer W is independent. Therefore, the developing solution supplied through the pipe  74  may be more dense than the developing solution supplied through the pipe  75 . Thus, the developing speed near the edge may become faster, preventing unequal development. 
     Moreover, by disposing a heating member (not shown) in the pipe  74 , the temperature of the developing solution discharged from the areas  73   a  and  73   g  at the edge of the wafer W may be controlled to be higher than the temperature of the developing solution discharged from the other areas  73   b ˜ 73   f . Thus, the developing speed near the edge may become faster, preventing unequal development. 
     Needless to say, the present invention is not to be restricted to the above-described embodiments. 
     For example, the present invention may be applied not only to a developing unit for developing the wafer W but also to a developing unit for developing other substrates such as an LCD substrate. 
     As mentioned above, the present invention is a developing apparatus having a nozzle with discharge ports arranged along a line for discharging a developing solution on the surface of a rotating target object. The nozzle is divided into a plurality of areas. Less developing solution is discharged from the discharge ports of an area at a rotating center of the target object as compared to other areas. The ratio of a pure developing solution supplied to the rotating center of the target object and the ratio of a pure developing solution supplied to the periphery of the target object is approximately the same. Thus, the development uniformity improves. 
     According to the invention, the areas are arranged to be approximately symmetrical about the rotating center of the target object. Therefore, the developing solution is supplied to the entire surface of the target object by rotating it for at least half a turn. The developing solution may also be supplied evenly in the rotating direction. 
     According to the invention, the amount of the developing solution discharged from each area decreases as the area approaches the rotating center of the target object. Therefore, the ratio of the pure developing solution supplied to the rotating center of the target object and the ratio of the pure developing solution supplied to the periphery of the target object become more accurately equal. Thus, the development uniformity further improves. 
     According to the invention, the “gap” of the discharge ports arising between the adjoining areas is prevented by composing the adjoining areas to partly overlap in the rotating direction of the target substrate. Thus, development becomes more uniform. 
     According to the invention, the timing when the developing solution reaches the surface of the target object corresponding to each area and the liquid pressure upon impact may be controlled by changing the height of the areas. Thus, uniform development is achieved. 
     The present invention is a developing apparatus having a nozzle with discharge ports arranged along a line for discharging a developing solution on the surface of a rotating target object. The nozzle is divided into a plurality of areas, and has a means disposed integrally for controlling an amount of the developing solution discharged from the discharge ports in each area. Therefore, the discharge time and amount of the developing solution discharged from each area may be controlled more accurately. The number of pipes for sending the developing solution to the nozzle may also be decreased. 
     According to the invention, the discharge time of the developing solution being discharged from each area is shorter as the areas approach the rotating center of the target object. Therefore, the ratio of the pure developing solution supplied to the rotating center of the target object and the ratio of the pure developing solution supplied to the periphery of the target object are approximately the same. Thus, unequal development may be decreased. 
     According to the invention, the means for controlling the discharge amount of the developing solution is an air-operating valve or an electromagnetic valve. Therefore, the on/off switching of the discharging of the developing solution is performed precisely. The discharge time and amount of the developing solution discharged from each area may also be controlled more accurately. 
     The invention has a means for controlling the amount of the developing solution discharged from the discharge ports of each area, disposed separately in the areas at the periphery of the target object and in other areas. Therefore, the ratio of the pure developing solution supplied to the rotating center of the target object and the ratio of the pure developing solution supplied to the periphery of the target object are approximately the same. Thus, unequal development is decreased. 
     According to the invention, the discharge time of the developing solution being discharged from the areas at the periphery of the target object is longer than the discharge time of the developing solution being discharged from the other areas. Therefore, the ratio of the pure developing solution supplied to the rotating center of the target object and the ratio of the pure developing solution supplied to the periphery of the target object are approximately the same. Thus, unequal development is decreased. 
     According to the invention, the density of the developing solution discharged from the areas at the periphery of the target object is higher than the density of the developing solution discharged from the other areas. Therefore, the developing speed is accelerated at the periphery of the target object and the development uniformity improves. 
     According to the invention, the temperature of the developing solution discharged from the areas at the periphery of the target object is higher than the temperature of the developing solution discharged from other areas. Therefore, the developing speed is accelerated at the periphery of the target object and unequal development decreases. 
     According to the invention, the discharge ports in the area at the rotating center of the target object are formed in a size becoming smaller as they approach the rotating center and discharging less developing solution. Therefore, the ratio of the pure developing solution near the center and at the periphery may be more even within the area at the rotating center. Thus, unequal development is decreased within the area at the rotating center. 
     The above-described embodiments are strictly intended to bring the technical contents of the present invention into focus. Therefore, the present invention should not be interpreted in a narrow sense by limiting to such a concrete example, but it is applicable in various forms within the range of the spirit of the present invention and the extent described in the claims.