Abstract:
A fluid injection apparatus for discharging a fluid against a surface in a controlled manner is disclosed. The fluid injection apparatus includes at least one fluid supply conduit, at least one rotatable and vertically-movable fluid injector provided in fluid communication with the fluid supply conduit and at least one fluid conduit provided in the fluid injector. By selective vertical movement of the fluid injector, each fluid conduit in the fluid injector can be selectively blocked from or provided in fluid communication with the fluid supply conduit to impart a desired flow configuration of a processing fluid against the surface. By selective rotational movement of the fluid injector, a rotational or swirling motion can be imparted to the fluid as it contacts the surface.

Description:
FIELD OF THE INVENTION 
   The present invention relates to apparatus used in the fabrication of semiconductors. More particularly, the present invention relates to a fluid injection apparatus, which facilitates the flow of processing fluids against a wafer surface in various flow and distribution patterns. 
   BACKGROUND OF THE INVENTION 
   In the fabrication of semiconductor integrated circuits, metal conductor lines are used to interconnect the multiple components in device circuits on a semiconductor wafer. A general process used in the deposition of metal conductor line patterns on semiconductor wafers includes deposition of a conducting layer on the silicon wafer substrate; formation of a photoresist or other mask such as titanium oxide or silicon oxide, in the form of the desired metal conductor line pattern, using standard lithographic techniques; subjecting the wafer substrate to a dry etching process to remove the conducting layer from the areas not covered by the mask, thereby leaving the metal layer in the form of the masked conductor line pattern; and removing the mask layer typically using reactive plasma and chlorine gas, thereby exposing the top surface of the metal conductor lines. Typically, multiple alternating layers of electrically conductive and insulative materials are sequentially deposited on the wafer substrate, and conductive layers at different levels on the wafer may be electrically connected to each other by etching vias, or openings, in the insulative layers and filling the vias using aluminum, tungsten or other metal to establish electrical connection between the conductive layers. 
   Normally in etchers and other semiconductor processing tools such as those used for the deposition of thin films on wafers, gases in the form of chemicals or fluids are injected or flowed towards the wafer surface for etching or deposition purposes. The direction of flow and distribution of the fluid on the wafer surface influences the etching rate or deposition rate, as well as the CD (critical dimension) uniformity or film thickness uniformity. Conventional processing tools use a fixed-type fluid injector or plate which provides flow of the fluid against the wafer in a fixed direction or distribution pattern. Therefore, under circumstances in which there exists a need to adjust the flow and distribution of the fluid on the wafer surface for purposes of etching or deposition uniformity, such tools are unsuitable. Therefore, a new and improved fluid injection apparatus is needed to facilitate flow of processing fluids against a wafer surface in various flow and distribution patterns depending on the particular processing requirements. 
   SUMMARY OF THE INVENTION 
   The present invention is generally directed towards a fluid injection apparatus for discharging a fluid against a surface in a positionally-controlled and directionally-controlled manner. The fluid injection apparatus includes at least one fluid supply conduit, at least one rotatable and vertically-movable fluid injector provided in fluid communication with the fluid supply conduit and at least one fluid conduit provided in the fluid injector. By selective vertical movement of the fluid injector, each fluid conduit in the fluid injector can be selectively blocked from or provided in fluid communication with the fluid supply conduit to impart a desired flow configuration of a processing fluid against the surface. By selective rotational movement of the fluid injector, a rotational or swirling motion can be imparted to the fluid as it contacts the surface. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
       FIG. 1  is a schematic of a mechanically-actuated embodiment of the fluid injection apparatus of the present invention, illustrating control of the flow of a fluid from the apparatus by rotational and vertical positional adjustment of a fluid injector; 
       FIG. 2  is a schematic of an illustrative electrically-actuated embodiment of the fluid injection apparatus of the present invention; 
       FIG. 3  is a schematic of the mechanically-actuated embodiment of the fluid injection apparatus, illustrating rotation of the fluid injector to facilitate swirling of a fluid as the fluid is dispensed from the fluid injector; 
       FIG. 4  is a schematic of the fluid injection apparatus, with the fluid injector located in a “high” position to facilitate wide fluid flow distribution; 
       FIG. 5  is a schematic of the fluid injection apparatus, with the fluid injector positioned to block flow of fluid through a central fluid conduit in the fluid injector and facilitate peripheral flow of fluid from the apparatus; 
       FIG. 6  is a schematic of the fluid injection apparatus, with the fluid injector in an uppermost position to block flow of fluid through both the central fluid conduit and an outer fluid conduit in the fluid injector and facilitate peripheral flow of fluid only from the apparatus; 
       FIG. 7  is a schematic of the fluid injection apparatus, with the fluid injector positioned to provide a narrow peripheral flow of fluid from the apparatus; 
       FIG. 8  is a schematic of the fluid injection apparatus, with the fluid injector positioned to block peripheral flow of fluid from the apparatus and restrict flow of fluid to the central fluid conduit and outer fluid conduit of the fluid injector only; and 
       FIG. 9  is a schematic of the fluid injection apparatus, with the fluid injector in a lowermost position to block peripheral flow of fluid from the apparatus and flow of the fluid through the outer fluid conduit and restrict flow of the fluid to the central fluid conduit of the fluid injector. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring initially to  FIG. 1 , an illustrative embodiment of a mechanically-actuated fluid injection apparatus, hereinafter apparatus, of the present invention is generally indicated by reference numeral  10 . The apparatus  10  is suitable for dispensing a fluid  30 , such as a processing liquid or gas used in semiconductor processing, for example, against the surface of a substrate (not shown) in a direction-controlled and position-controlled manner during the fabrication of integrated circuits on the substrate. The apparatus  10  may be installed, for example, in an etching chamber (not shown) for dispensing an etching fluid  30  against the wafer, or a chemical vapor deposition (CVD) chamber (not shown) for dispensing a deposition gas  30  against the wafer, for example. It is understood that the apparatus  10  may be used in other industrial applications in which it is desired to dispense a fluid against a substrate in a direction-controlled and position-controlled manner. 
   As shown in  FIG. 1 , the apparatus  10  includes a fluid injector  12  which is mounted for selective vertical movement inside an outer isolation cover  32  by operation of a magnetic coupling device  13 . The bottom end of the fluid injector  12  is typically flared outwardly. An isolation flange  34  extends inwardly from the outer isolation cover  32  and sealingly engages the outer surface of the fluid injector  12 . The outer isolation cover  32  includes a fluid partition  33 , which extends outwardly from the bottom end of the main portion of the outer isolation cover  32 . A fluid supply conduit  11  is provided in a fluid flow space  11   a  beneath the fluid partition  33  to supply a stream of the processing fluid  30  to the apparatus  10 . 
   The fluid injector  12  is typically cylindrical and includes an inner magnet  14  and an inner magnet  16  which are of opposite polarity and disposed at opposite or diametrically-opposed sides or edges of the fluid injector  12 . A “T” shaped central fluid conduit  18  extends through the fluid injector  12 , beneath the inner magnets  14 ,  16 . The central fluid conduit  18  includes a horizontal segment which extends horizontally through the fluid injector  12  and a vertical segment which extends downwardly from the horizontal segment and opens at the flared bottom end of the fluid injector  12 . 
   An annular plate cavity  20  is provided in the outer surface of the fluid injector  12  and encircles the vertical segment of the central fluid conduit  18 . An annular stationary magnet  28  is provided in the fluid injector  12 , inside and adjacent to the plate cavity  20 . A floating isolation plate  24 , which typically has an annular configuration, is mounted for vertical movement in the plate cavity  20 . An annular floating magnet  26 , having a magnetic polarity which is opposite that of the stationary magnet  28 , is provided in the floating isolation plate  24 . An outer fluid conduit  22  extends from the plate cavity  20 , through the fluid injector  12  and opens at the flared bottom of the fluid injector  12 . The discharge segment of the outer fluid conduit  22  is typically disposed at an angle with respect to the central fluid conduit  18  and may be generally parallel to the outwardly-flared contour of the bottom end of the fluid injector  12 . The outer fluid conduit  22  has an upper inlet  22   a  and a lower inlet  22   b  which communicate with the plate cavity  20  and are provided at the upper and lower ends, respectively, of the stationary magnet  28 . 
   Due to magnetic attraction between the stationary magnet  28  and the floating magnet  26 , the floating isolation plate  24  is normally positioned at substantially the vertical center of the plate cavity  20 , about equidistant between the upper inlet  22   a  and lower inlet  22   b  of the outer fluid conduit  22 . Responsive to raising or lowering of the fluid injector  12  with respect to the outer isolation cover  32 , however, the floating isolation plate  24  can be caused to block the upper inlet  22   a  or lower inlet  22   b  and prevent discharge of the fluid  30  from the outer fluid conduit  22 , as will be hereinafter described. 
   An annular inner isolation plate  56  surrounds the fluid injector  12 . The fluid injector  12  extends through a peripheral fluid conduit  58  which extends through the center of the inner isolation plate  56 . The inside edge of the peripheral fluid conduit  58  is typically angled outwardly to generally correspond to the outwardly-flared shape of the bottom end of the fluid injector  12 . 
   The magnetic coupling device  13  includes an annular fixed plate  44  which is mounted above the fluid partition  33 . The fixed plate  44  encircles the outer isolation cover  32 . A drive shaft  50  is journalled for rotation in the fixed plate  44 , and a rotational drive motor  48  drivingly engages the drive shaft  50 . A drive gear  46  is provided on the drive shaft  50 . An annular gear plate  42  is rotatably mounted above the fixed plate  44  and meshes with the drive gear  46 . A lead rod  40  extends downwardly from one side of the gear plate  42 , and a moving plate  36  extends horizontally from the lead rod  40 , beneath the gear plate  42 . An outer magnet  17 , which is disposed in magnetic proximity and is opposite in magnetic polarity to the inner magnet  14  on the fluid injector  12 , is provided on the moving plate  36 . A lead screw  38  extends downwardly through the opposite side of the gear plate  42  and is mounted in a bearing  38   a  provided on the moving plate  36 . A vertical drive motor  39  drivingly engages the upper end of the lead screw  38 . An outer magnet  15 , which is disposed in magnetic proximity and opposite in magnetic polarity to the inner magnet  16 , is provided on the moving plate  36 . A gear shaft  54  is journalled for rotation on the fixed plate  44 , typically in diametrically-opposed relationship to the drive gear  46 . A holding gear  52  is mounted on the gear shaft  54  and meshes with the gear plate  42 . 
   As shown in  FIG. 1 , vertical positional adjustment of the fluid injector  12  in the outer isolation cover  32  is selectively carried out by operation of the vertical drive motor  39 . Accordingly, the vertical drive motor  39  rotates the lead screw  38 , which causes the moving plate  36  to travel upwardly or downwardly on the lead screw  38 , depending on the direction of rotation of the lead screw  38 . This, in turn, raises or lowers the fluid injector  12  due to the magnetic attraction between the outer magnets  15 ,  17  and inner magnets  16 ,  14 , respectively. Clockwise or counterclockwise rotation of the fluid injector  12  in the outer isolation cover  32  is selectively carried out by operation of the rotational drive motor  48 . Accordingly, the rotational drive motor  48  rotates the drive gear  46  through the drive shaft  50 . The drive gear  46 , in turn, rotates the gear plate  42 , causing the outer magnets  15 ,  17  on the moving plate  36  to rotate as they magnetically attract the respective inner magnets  16 ,  14  on the fluid injector  12 , thus causing the fluid injector  12  to rotate in the same direction as the gear plate  42 . 
   Referring next to  FIG. 2 , an alternative, electrically-actuated embodiment of the fluid injection apparatus of the present invention is generally indicated by reference numeral  10   a . The apparatus  10   a  includes a magnetic coupling device  13   a  which uses magnetic induction effects instead of the vertical drive motor  39  and rotational drive motor  48  heretofore described with respect to the apparatus  10  of  FIG. 1  to facilitate vertical and rotational movement of the fluid injector  12 . The apparatus  10   a  utilizes multiple sets of bottom electrical coils  62 , middle electrical coils  64  and top electrical coils  66  which are provided around the outer isolation cover  32 . Accordingly, by the selective distribution of electrical current through the bottom electrical coils  62 , the middle electrical coils  64  and/or the top electrical coils  66 , the fluid injector  12  can be selectively raised or lowered in the outer isolation cover  32  by magnetic attraction between the inner magnets  14 ,  16  and the energized electrical coils. In similar fashion, the fluid injector  12  can be selectively rotated in the outer isolation cover  32  by time-varying the distribution of electrical current through the electrical coils in a circular pattern around the outer isolation cover  32 . While operation of the invention will be hereinafter described with respect to the apparatus  10 , the apparatus  10   a  can be operated in similar fashion to accomplish the purposes of the invention. 
   Referring next to FIGS.  1  and  3 - 9 , the fluid injection apparatus  10  is suitable to serve as a FDP (Fluid Distribution Plat) for semiconductor manufacturing. The fluid injection apparatus  10  is typically installed in a processing chamber (not shown) used in the fabrication of semiconductor devices on a semiconductor wafer (not shown). Accordingly, the outer isolation cover  32  and the fluid partition  33  sealingly separate the vacuum or low-pressure region of the chamber interior beneath the outer isolation cover  32  from the atmospheric pressure region above the outer isolation cover  32 . The apparatus  10  can be operated to distribute a processing fluid  30 , such as an etching gas or liquid or a film-forming gas or liquid, for example, in the fabrication of integrated circuits, from the fluid supply conduit  11  onto the surface of a semiconductor wafer (not shown), for example in a selected flow pattern. The fluid injector  12  can be raised, lowered and/or rotated in the outer isolation cover  32  to facilitate selective flow of the fluid  30  through the central fluid conduit  18 , the outer fluid conduit  22  and/or the peripheral fluid conduit  58  in order to control the positional and directional flow characteristics of the fluid  30  on the surface of the wafer. This, in turn, facilitates uniform etching and/or deposition of films on the wafer surface. For purposes of discussion herein, the fluid  30  will be described as having a first portion  30   a  which flows through and is discharged from the central fluid conduit  18 , a second portion  30   b  which flows through and is discharged from the outer fluid conduit  22 , and a third portion  30   c  which flows through and is discharged from the peripheral fluid conduit  58 . 
   In one possible application of the invention, the apparatus  10  is installed in a chemical vapor deposition (CVD) chamber (not shown) which is used to deposit a dielectric layer (not shown) on a wafer (not shown). Accordingly, the processing fluid  30 , which is the gas containing the deposition components for formation of the dielectric layer, are distributed through the apparatus  10 , via the central fluid conduit  18 , outer fluid conduit  22  and/or peripheral fluid conduit  58 , in a controlled flow pattern to impart uniformity to the dielectric layer. 
     FIG. 1  illustrates operation of the apparatus  10  to facilitate maximal flow of the fluid  30  onto the wafer. Accordingly, the first portion  30   a  of the fluid  30  initially flows through the central fluid conduit  18  and is then discharged in a substantially vertical path directly against the surface of the wafer from the bottom end of the fluid injector  12 . Simultaneously, the second portion  30   b  of the fluid  30  flows into the plate cavity  20 ; through the upper inlet  22   a  and lower inlet  22   b  of the outer fluid conduit  22 ; and is discharged from the outer fluid conduit  22  at the bottom of the fluid injector  12 , at an angle with respect to the flow path of the first portion  30   a  of the fluid  30 . Therefore, the second portion  30   b  of the fluid  30  flows outwardly and strikes the surface of the wafer at an angle. The third portion  30   c  of the fluid  30  flows downwardly and outwardly through the peripheral fluid conduit  58  and strikes the wafer in an outwardly-angled, annular flow path. 
     FIG. 3  illustrates operation of the apparatus  10  wherein the fluid injector  12  is rotated by operation of the rotational drive motor  48  as the first portion  30   a  of the fluid  30  is distributed through and discharged from the central fluid conduit  18  and the second portion  30   b  of the fluid  30  is distributed through and discharged from the outer fluid conduit  22 . Accordingly, the first portion  30   a  strikes the surface of the wafer directly, whereas the second portion  30   b  is ejected from the outer fluid conduit  22  and strikes the surface of the wafer in a rotating or spiraling motion. The third portion  30   c  is typically ejected outwardly from the apparatus  10  through the peripheral fluid conduit  58  and strikes the surface of the wafer in an outwardly-angled, annular flow path. 
     FIG. 4  illustrates operation of the apparatus  10  wherein the fluid injector  12  is in an upper position in the outer isolation cover  32  and the floating isolation plate  24  is spaced from the inner isolation plate  56  across a relatively large gap. This facilitates flow of a relatively large quantity of the second portion  30   b  of the fluid  30  through the peripheral fluid conduit  58  and against the surface of the wafer in a wide, outwardly-angled annular flow path. Simultaneously, the central fluid conduit  18  is partially blocked by the outer isolation cover  32 , thus partially restricting the quantity of the first portion  30   a  which flows through and is discharged from the central fluid conduit  18 . The second portion  30   b  is ejected outwardly from the outer fluid conduit  22  and strikes the surface of the wafer at an angle. This results in widespread distribution of fluid flow across the surface of the wafer. 
     FIG. 5  illustrates operation of the apparatus  10  wherein the fluid injector  10 , as compared to its position in  FIG. 4 , is at a higher position in the outer isolation cover  32 , such that the floating isolation plate  24  engages the bottom surface of the fluid partition  33  and the horizontal segment of the central fluid conduit  18  is located entirely inside the outer isolation cover  32 . Accordingly, the first portion  30   a  of the fluid  30  is incapable of entering and being discharged from the central fluid conduit  18 . Although the upper inlet  22   a  of the outer fluid conduit  22  is blocked by engagement of the floating isolation plate  24  against the fluid partition  33 , the second portion  30   b  of the fluid  30  is still able to flow into and from the outer fluid conduit  22  through the plate cavity  20  and lower inlet  22   b , respectively. Furthermore, due to the maximal width of the gap between the floating isolation plate  24  and the inner isolation plate  56 , a relatively large quantity of the third portion  30   c  of the fluid  30  flows through the peripheral fluid conduit  58  and is ejected outwardly against the surface of the wafer in an annular flow path. 
     FIG. 6  illustrates operation of the apparatus  10  wherein the fluid injector  12  is in the uppermost position inside the outer isolation cover  32 . Accordingly, the first portion  30   a  of the fluid  30  is incapable of being ejected from the central fluid conduit  18  because the horizontal segment of the central fluid conduit  18  is located entirely inside the outer isolation cover  32 . Furthermore, the floating isolation plate  24  has been urged downwardly against the bottom of the plate cavity  20 , against the upward bias imparted by the magnetic attraction between the stationary magnet  28  and the floating magnet  26 , such that the lower inlet  22   b  is blocked to prevent flow of the second portion of the fluid  30   b  through and discharge of the fluid  30   b  from the outer fluid conduit  22 . However, due to the maximum width of the gap between the floating isolation plate  24  and the inner isolation plate  56 , a maximal quantity of the third portion  30   c  of the fluid  30  flows through the peripheral fluid conduit  58  and is ejected outwardly against the surface of the wafer in an annular flow path. 
     FIG. 7  illustrates operation of the apparatus  10  wherein the width of the peripheral fluid conduit  58  is restricted by the close proximity of the floating isolation plate  24  to the inner isolation plate  56 . Accordingly, a relatively small quantity of the third portion  30   c  of the fluid  30  is capable of flowing outwardly in an annular flow path against the surface of the wafer through the peripheral fluid conduit  58 . The first quantity  30   a  of the fluid  30  flows through and is ejected from the central fluid conduit  18  directly against the surface of the wafer. The second quantity  30   b  of the fluid  30  flows through and is ejected outwardly from the outer fluid conduit  22  against the surface of the wafer. 
     FIG. 8  illustrates operation of the apparatus  10  wherein the peripheral fluid conduit  58  is closed by engagement of the floating isolation plate  24  with the inner isolation plate  56 . Accordingly, the third portion  30   c  of the fluid  30  is incapable of flowing through the peripheral fluid conduit  58  and outwardly against the surface of the wafer. The first portion  30   a  of the fluid  30  flows through and is discharged from the central fluid conduit  18 , and the second portion  30   b  of the fluid  30  flows into the outer fluid conduit  22  through the plate cavity  20  and upper inlet  22   a , respectively, and is discharged outwardly against the wafer from the bottom of the fluid injector  12 . 
     FIG. 9  illustrates operation of the apparatus  10  wherein the fluid injector  12  is in the lowermost position in the outer isolation cover  32 . Accordingly, the floating isolation plate  24  engages both the inner isolation plate  56  and the upper surface of the plate cavity  20 . Therefore, the floating isolation plate  24  seals the upper inlet  22   a  and the lower inlet  22   b  of the outer fluid conduit  22 , thereby preventing flow of the second portion  30   b  of the fluid  30  through the outer fluid conduit  22 . The floating isolation plate  24  also seals the peripheral fluid conduit  58  of the inner isolation plate  56 , thus preventing flow of the third portion  30   c  of the fluid  30  from the apparatus  10  against the wafer. Thus, the entire quantity of fluid  30   a  is restricted to flow through the central fluid conduit  18  and is directly discharged against the surface of the wafer. 
   While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications can be made in the invention and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention.