Abstract:
A combination nozzle for applying a developer material and a washing solution material at different time intervals to a photoresist material layer disposed on a wafer is provided. The combination nozzle includes a number of developer nozzle tips connected to a developer supply line and a number of washing solution nozzle tips connected to a washing solution supply line. The developer supply line and the washing solution supply line ensure that the developer material and the washing solution material are always substantially isolated from one another. Furthermore, the developer nozzle tips and the washing solution nozzle tips are arranged so that developer material and washing solution material do not come into contact with one another. The volume of the material and the volume flow of the material can be controlled by electronically controlled valves.

Description:
TECHNICAL FIELD 
     The present invention generally relates to semiconductor processing, and in particular to a common nozzle for applying a developer material and a washing solution material at different time intervals to a photoresist material layer disposed on a semiconductor wafer. 
     BACKGROUND OF THE INVENTION 
     In the semiconductor industry, there is a continuing trend toward higher device densities. To achieve these high densities there has been and continues to be efforts toward scaling down device dimensions (e.g., at submicron levels) on semiconductor wafers. In order to accomplish such high device packing density, smaller and smaller features sizes are required. This may include the width and spacing of interconnecting lines, spacing and diameter of contact holes, and the surface geometry such as corners and edges of various features. 
     The requirement of small features with close spacing between adjacent features requires high resolution photolithographic processes. In general, lithography refers to processes for pattern transfer between various media. It is a technique used for integrated circuit fabrication in which a silicon structure is coated uniformly with a radiation-sensitive film, the resist, and an exposing source (such as optical light, x-rays, or an electron beam) illuminates selected areas of the surface through an intervening master template, the mask, for a particular pattern. The lithographic coating is generally a radiation-sensitive coating suitable for receiving a projected image of the subject pattern. Once the image is projected, it is indelibly formed in the coating. The projected image may be either a negative or a positive image of the subject pattern. Exposure of the coating through a photomask causes the image area to become either more or less soluble (depending on the coating) in a particular solvent developer. The more soluble areas are removed in the developing process to leave the pattern image in the coating as less soluble polymer. 
     Due to the extremely fine patterns which are exposed on the photoresist material, thickness uniformity of the photoresist material is a significant factor in achieving desired critical dimensions. The photoresist material should be applied such that a uniform thickness is maintained in order to ensure uniformity and quality of the photoresist material layer. The photoresist material layer thickness typically is in the range of 0.1 to 3.0 microns. Good resist thickness control is highly desired, and typically variances in thickness should be less than±10-20 Å across the wafer. Very slight variations in the photoresist material thickness may greatly affect the end result after the photoresist material is exposed by radiation and the exposed portions removed. 
     Application of the resist onto the wafer is typically accomplished by using a spin coater. The spin coater is essentially a vacuum chuck rotated by a motor. The wafer is vacuum held onto the spin chuck. Typically, a nozzle supplies a predetermined amount of resist to a center area of the wafer. The wafer is then accelerated to and rotated at a certain speed, and centrifugal forces exerted on the resist cause the resist to disperse over the whole surface of the wafer. The resist thickness obtained from a spin coating process is dependent on the viscosity of the resist material, spin speed, the temperature of the resist and temperature of the wafer. 
     After the resist is spin coated and selectively irradiated to define a predetermined pattern, the irradiated or nonirradiated portions are removed by applying a developer material. The developer material is also spin coated onto the wafer by applying developer material across the resist and then spin coating the developer material until centrifugal forces disperse the developer material over the coating of resist. Due to the surface of the photoresist material layer on the semiconductor being highly hydrophobic, the surface can repel the developer material at the initial state of jetting out the developer material from the developer supply nozzle so that turbulent flow of the developer material is generated on the surface of the resist forming bubbles. The bubbles produced between the photoresist material layer and the developer material are a cause of defects in the resist pattern. A solution to this problem has been to apply a washing solution material or liquid (e.g. water), that is typically used in a rinsing or washing process, onto the photoresist material layer and spin coat the washing solution material to form a washing solution material film. The developer material is then applied to the wafer and the spin coated onto the wafer and the washing solution material film is scattered off the surface of the photoresist material layer leaving only the developer material. After the photoresist material layer has been developed, the irradiated or nonirradiated portions are removed by rinsing or washing with the washing solution material. Each time the washing solution material is applied to the photoresist material layer, a washing solution nozzle is presented above the wafer and the washing solution material is applied. The washing solution nozzle then returns to its rest position and the developer nozzle moves to the center of the photoresist material layer and applies the developer material. The developer nozzle then moves to the rest position and the washing solution nozzle moves above the wafer to rinse the developed portions and the developer material off the photoresist material layer. This constant movement of the different nozzles not only takes up a great deal of time, but eventually leads to mechanical problems and increased maintenance. 
     A prior art developer nozzle and washing solution application system is illustrated in FIGS. 1 a - 1   b . A multiple tip developer nozzle  10  is coupled to a pivotable arm  12  that pivots from a rest position to an operating position. In the operating position, the multiple tip nozzle  10  applies a developer material  26  on a resist layer  24  disposed on a wafer  22 . The wafer  22  is vacuum held onto a rotating chuck  20  driven by a shaft  18  coupled to a motor  16 . The developer material flows outward from the center of the photoresist material layer  24  covering the entire top surface of the photoresist material layer  24 . A washing solution nozzle  28  is coupled to an arm  32  and moves from an operating position to a rest position. The washing solution nozzle supplies water by providing a washing solution material film prior to applying the developer material, and also providing a rinse to the developed portions and the developer material from the developed photoresist material  24 . As illustrated in FIG. 1 a , the washing solution nozzle  28  is typically at a much greater distance from the photoresist material layer in its operating state than the developer nozzle is when it is in its operating state resulting in a splashing effect that can result in scattering particles and causing defects. Furthermore, the developer nozzle  28  is specifically designed to apply a uniform layer of developer material, while the washing solution nozzle  28  is typically a water faucet type of arrangement and designed to rinse the developed photoresist off the wafer. Therefore, the washing solution nozzle does not have the advantages associated with the developer nozzle. 
     A common nozzle for applying both a developer material and a washing solution material has not been employed because the undesirability of the nozzle coming in contact with two completely different materials, which can affect the usefulness of each material. In view of the above, a nozzle is needed, for dispensing not only a uniformly thick layer of developer material across a photoresist material layer formed on a wafer, but also for dispensing a uniformly thick layer of washing solution material on the photoresist material layer, while substantially avoiding any mixing of the two materials with one another. Additionally, there is a need to eliminate the constant movement of the developer nozzle and the washing solution nozzle from the operating position to the rest position. 
     SUMMARY OF THE INVENTION 
     The present invention provides a combination nozzle for applying a developer material and a washing solution material at different time intervals to a photoresist material layer disposed on a wafer. The combination nozzle includes a plurality of developer nozzle tips connected to a developer supply line and a plurality of washing solution nozzle tips connected to a washing solution supply line. The developer supply line and the washing solution supply line ensure that the developer material and the washing solution material are substantially isolated from one another. Furthermore, the plurality of developer nozzle tips and the plurality of washing solution nozzle tips are arranged, so that developer material and washing solution material are substantially isolated from one another, so that any intermingling of the materials does not diminish its effectiveness or function. Preferably, the two materials are completely isolated from one another. The volume of the material and the volume flow of the material can be controlled by electronically controlled valves. 
     One particular aspect of the invention relates to a multiple tip nozzle for applying a material onto a photoresist material layer disposed on a substrate. The nozzle includes a nozzle body and a developer distribution line enclosed in the nozzle body. The developer distribution line is adapted to be connected to a supply of developer material. The nozzle also includes a plurality of developer nozzle tips extending from the nozzle body which are in a communicative relationship with the developer distribution line. A washing solution distribution line enclosed in the nozzle body is also provided. The washing solution distribution line is adapted to be connected to a supply of washing solution material and a plurality of washing solution nozzle tips extend from the nozzle body and are in a communicative relationship with the washing solution distribution line. The developer distribution line and the washing solution distribution line are substantially isolated from one another and the nozzle is adapted to apply onto the photoresist material layer both a developer material and a washing solution material at different time intervals. 
     Another aspect of the present invention relates to a multiple tip nozzle for applying a material onto a photoresist material layer disposed on a substrate. The nozzle includes a nozzle body, a developer distribution line adapted to be connected to a supply of developer material, a plurality of developer nozzle assemblies extending from the nozzle body and being in a communicative relationship with the developer distribution line, a washing solution distribution line adapted to be connected to a supply of developer material and a plurality of washing solution nozzle assemblies extending from the nozzle body and being in a communicative relationship with the washing solution distribution line. The plurality of developer nozzle tip assemblies and the plurality of washing solution nozzle assemblies are substantially isolated from one another. 
     Another aspect of the present invention relates to a multiple tip nozzle for applying a material onto a photoresist material layer disposed on a substrate. The nozzle includes means for distributing a developer material to a plurality of developer nozzle tips, means for distributing a washing solution material to a plurality of washing solution nozzle tips and means for substantially isolating the means for distributing the developer material and the means for distributing the washing solution material. 
     Yet another aspect of the present invention relates to a method for applying a material onto a photoresist material layer disposed on a substrate. The method includes the steps of providing a combination nozzle that supplies both a developer material and a washing solution material, spinning the photoresist material layer on the substrate, moving the combination nozzle to an operating position above the photoresist material layer, applying the developer material until the photoresist material layer is covered by the developer material, stopping the spinning of the substrate until the developer material develops the photoresist material layer, rinsing the wafer with washing solution material, and moving the combination nozzle to a rest position. 
     To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 a  illustrates a front view of a developer material and washing solution material application system in accordance with the prior art; 
     FIG. 1 b  illustrates a top view of the developer material and washing solution material application system illustrated in FIG. 1 a  in accordance with the prior art; 
     FIG. 1 illustrates a front view of a developer material and washing solution material application system inaccordance with prior art; 
     FIG. 2 a  illustrates a cross-sectional view of an embodiment of a combination nozzle in accordance with the present invention; 
     FIG. 2 b  illustrates a cross-sectional view of an alternate embodiment of a combination nozzle in accordance with the present invention; 
     FIG. 3 a  illustrates a bottom view of a nozzle with a nozzle arrangement in accordance with the present invention; 
     FIG. 3 a  illustrates a side view of the nozzle of FIG. 3 a  in accordance with the present invention; 
     FIG. 3 b  illustrates a side view of the nozzle of FIG. 3 a  in accordance with the present invention; 
     FIG. 4 a  illustrates a bottom view of a nozzle with an alternate nozzle arrangement in accordance with the present invention; 
     FIG. 4 b  illustrates a side view of the nozzle of FIG. 4 a  in accordance with the present invention; 
     FIG. 5 a  illustrates a bottom view of a nozzle with another nozzle arrangement in accordance with the present invention; 
     FIG. 5 b  illustrates a side view of the nozzle of FIG. 5 a  in accordance with the present invention; 
     FIG. 6 a  illustrates a bottom view of a nozzle with yet another nozzle arrangement in accordance with the present invention; 
     FIG. 6 b  illustrates a side view of the nozzle of FIG. 6 a  in accordance with the present invention; 
     FIG. 7 a  illustrates a bottom view of a nozzle with yet another nozzle arrangement in accordance with the present invention; 
     FIG. 7 b  illustrates a side view of the nozzle of FIG. 7 a  in accordance with the present invention; 
     FIG. 8 illustrates a cross-sectional view of a nozzle with nozzle tip assemblies in accordance with the present invention; and 
     FIG. 9 is a flow diagram illustrating one specific methodology for carrying out the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. The present invention will be described with reference to a nozzle that provides both a supply of developer material and a supply of washing solution material from the same nozzle, while substantially isolating the developer material and the washing solution material from one another. It should be understood that the description of these embodiments are merely illustrative and that they should not be taken in a limiting sense. 
     Referring initially to FIG. 2 a , a multiple tip developer nozzle  40  is provided including a handle  62  connected to an arm  60  by a coupling  64 . The nozzle  40  includes a nozzle body  54  with an input supply enclosure  56  and an output supply enclosure  58  extending from the nozzle body  54 . A plurality of developer nozzle tips  66  and a plurality of washing solution nozzle tips  70  are connected to the nozzle body  54 . A developer input supply tube  42  is connected to a supply of developer material (not shown) on one end and is connected to a developer distribution line  46  on the other end. Each of the developer nozzle tips  66  are connected to the developer distribution line  46  by a developer channel  68 . A developer material is provided to the developer distribution line  46  through the developer input supply tube  42  and distributed through the developer nozzle tips  66 . The excess developer material exits the nozzle body  54  through a developer output supply tube  44 . The developer output supply tube  44  can be connected to a pump, a vacuum or the like for removing excess developer material. A washing solution input supply tube  48  is connected to a supply of washing solution material (not shown) on one end and is connected to a washing solution distribution line  52  on the other end. Each of the washing solution nozzle tips  70  are connected to the washing solution distribution line  52  by a washing solution channel  69 . A washing solution material is provided to the washing distribution line  52  through the washing solution input supply tube  48  and distributed through the washing solution nozzle tips  70 . The excess washing solution material exits the nozzle body  54  through a washing solution output supply tube  50 . The washing solution output supply tube  50  can be connected to a pump, a vacuum or the like for removing excess washing solution material. The nozzle  40  substantially isolates the washing solution material and the developer material from contact with one another. 
     An alternate embodiment of the nozzle  40  is illustrated in FIG. 2 b . In the alternate embodiment, a developer input supply tube  75  is enclosed by a washing solution input chamber  74 . The developer input supply tube  75  extends beyond the washing solution input chamber  74  and is connected to a developer distribution line  76 . Each of the developer nozzle tips  66  are connected to the developer distribution line  76  by a developer channel  68 . A developer material is provided to the developer distribution line  76  through the developer input supply tube  75  and is distributed through the developer nozzle tips  66 . The excess developer material exits the nozzle body  54  through a developer output supply tube  80 , which is enclosed by a washing solution output chamber  78 . A washing solution distribution line  82  connects the washing solution input chamber  74  to the washing solution output chamber  78 . A washing solution material is provided to the washing solution distribution line  82  through the washing solution input chamber  74  and distributed to each washing solution nozzle tip  70  through a washing solution channel  69 . The excess washing solution material exits out through the washing solution output supply chamber  78 . In the alternate embodiment illustrated in FIG. 2 b , the washing solution material flows around the developer tubes  75  and  80 , while the developer material flows within the tubes  75  and  80  ensuring that the washing solution material and developer material remain substantially isolated from one another. 
     FIGS. 3 a - 3   b  to FIGS. 7 a - 7   b  illustrate particular arrangements of the developer nozzle tips  66  and the washing solution nozzle tips  70  on the nozzle body  54 , such that distribution of one material does not come into contact with the nozzle tips of the other material, so that contamination of one material by the other is avoided. Referring initially to FIGS. 3 a - 3   b , the nozzle body  54  includes a bottom surface  84  connected to a side surface  81  by a sloping surface  85 . The developer nozzle tips  66  and the washing solution nozzle tips  70  are arranged along a longitudinal length of the sloping surface  85  in an alternating fashion. Dispensing of developer material from the developer nozzle tips  66  and dispensing washing solution material from the washing solution nozzle tips  70  does not cause contact with any of the nozzle tips dispensing the other material. 
     In another embodiment illustrated in FIGS. 4 a - 4   b , the nozzle body  54  includes the bottom surface  84  and a first sloping surface  86  connected to a second sloping surface  87  which is connected to the side surface  81 . The first sloping surface  86  and the second sloping surface  87  form a beveled edge  79 . The developer nozzle tips  66  are arranged along a longitudinal length of the first sloping surface  86  and the washing solution nozzle tips  70  are arranged along a longitudinal length of the second sloping surface  87 . The developer nozzle tips  66  and the washing solution nozzle tips  70  are arranged in an offset manner from one another, so that dispensing of one material does not come into contact with the nozzle tip of the other material. 
     In yet another embodiment of the invention as illustrated in FIGS. 5 a - 5   b , the developer nozzle tips  66  are arranged on the bottom surface  84  of the nozzle body  54  along a first longitudinal length of the bottom surface  84 . The washing solution nozzle tips  70  are also arranged on the bottom surface  84  of the nozzle body  54  along a second longitudinal length of the bottom surface  84 , where the second length is parallel to the first length. In yet another embodiment of the invention illustrated in FIGS. 6 a - 6   b , the developer nozzle tips  66  are arranged along the sloped surface  85  similarly to the arrangement illustrated in FIGS. 3 a - 3   b , except that the washing solution nozzle tips  70  are arranged on the bottom surface  84  of the nozzle body  54  along a longitudinal length of the bottom surface  84 . 
     FIGS. 7 a - 7   b  illustrate yet another embodiment of the arrangement of the developer nozzle tips  66  and the washing solution nozzle tips  70 . The developer nozzle tips are arranged on the sloped surface  85  similarly to the arrangement illustrated in FIGS. 3 a - 3   b  and FIGS. 6 a - 6   b . However, the washing solution nozzle tips  66  are arranged on a sloped surface  88  connecting the bottom surface  84  to a side  83  opposite the side  81 . In this type of arrangement, the nozzle  40  may have to be adjusted slightly during application of the washing solution material as opposed to application of the developer material, depending on the location of the nozzle during dispensing. 
     FIG. 8 illustrates yet another embodiment of the present invention where control of the volume flow and volume flow rate is provided for each of the nozzle tips. Although the control of the volume flow and the volume flow rate will be explained with reference to distributing the developer material, it is to be appreciated that the same control can be employed for distributing the washing solution material. The nozzle  40  includes a holder  95  defining a chamber  102  that holds a plurality of nozzle tips assemblies  97 . Each nozzle tip assembly  97  includes a developer supply tube  90  with one end disposed in the holder  95  and the other end connected to a supply of developer material (not shown). A volume control valve  94  controls the volume of developer received into a receiving chamber  92  from the developer supply tube  90 . A collar  98  is connected to the bottom of the holder  95  and includes a central aperture for allowing a development supply barrel  96  to pass therethrough. The collar  98  threadingly engages the holder  95  via threads  91  on both the collar  98  and the holder  95 . Supply barrel  96  is connected to the receiving chamber  92  on one end and passes through the center of collar  98 . The supply barrel  96  includes a liquid discharge opening  100  that discharges the developer material to a photoresist material layer  104  disposed on a substrate  106 . A volume of developer material is received in the receiving chamber  92  depending on the setting of the volume control valve  94 . The chamber  92  and the tip  100  cooperate to deposit developer material at a controlled flow rate onto the photoresist material layer  104 . A second control valve  93  can be placed between the receiving chamber  92  and the liquid discharge opening  100  for selectively controlling the developer material flow rate from the receiving chamber to the photoresist material layer  104 . In an alternate embodiment, a first volume control valve supplies the developer supply line  46  or  76  with the developer material and a second volume control valve supplies the washing solution material to the washing solution supply line  52  or  82 . These first and second volume control valves can also be used to control the volume flow of the developer material and the washing solution material, respectively. 
     FIG. 9 is a flow diagram illustrating one particular methodology for carrying out the present invention. In step  120 , a wafer is spun to a washing solution material application speed. In step  130 , a combination developer material and washing solution material material nozzle is moved to the center of a photoresist material layer disposed on the wafer. In step  140 , a washing solution material is applied until the photoresist material layer is covered with a film layer of washing solution material. The wafer is then spun to a developer material application speed and a developer material is applied until a developer material layer covers the photoresist material layer and the washing solution material is removed in step  150 . In step  160 , the wafer is stopped until the photoresist material layer is developed. In step  170 , the wafer is rinsed with the washing solution material. The combination developer material and washing solution nozzle is then moved to its rest position in step  180 . The process can then be repeated for the next wafer. 
     What has been described above are preferred embodiments of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.