Abstract:
Semiconductor manufacturing equipment is disclosed and comprises a robot comprising a robotic arm adapted to transfer a wafer from a wafer cassette in a load lock chamber to a processing chamber with proper alignment and positioning without the need to intermediately pass through a support chamber specially adapted to align and position the wafer.

Description:
BACKGROUND AND SUMMARY  
       [0001]     1 . Field of the Invention  
         [0002]     Embodiments of the invention relate to semiconductor manufacturing device adapted to transfer a wafer by means of a robot. More particularly, embodiments of the invention relate to a semiconductor manufacturing device adapted for use with a robot and more efficiently adapted to transfer a properly aligned and positioned wafer amongst processing chambers.  
         [0003]     A claim of priority is made to Korean Patent Application 10-2005-0059661 filed on Jul. 4, 2005, the subject matter of which is hereby incorporated by reference in its entirety.  
         [0004]     2. Description of the Related Arts  
         [0005]     The manufacture of semiconductor devices involves an application of a complex sequence of fabrication processes to a substrate (e.g., a silicon wafer) on which the semiconductor devices are to be formed. Common fabrication processes include processes related to photolithography, etching, ion implantation, diffusion, metal deposition, etc.  
         [0006]     Various specialized pieces of manufacturing equipment perform the fabrication processes. Thus, it is necessary to physically transfer wafers between the equipment. Given the very real concerns over possible contamination of and/or damage to the wafers, transfer of the wafers is a difficult problem. Each unique piece of fabrication equipment may define a unique position and alignment at which it accepts one or more wafers for processing, or a unique staging position preparatory to processing. Thus, the transfer process must ensure accurate transfer and alignment of wafers as between various pieces of fabrication equipment.  
         [0007]     One example of conventional transfer and alignment of wafers will now be described with reference to Figure ( FIG. 1 ). Referring to  FIG. 1 , semiconductor manufacturing equipment  10  is associated with a semiconductor manufacturing line and adapted to transfer one or more wafers W. The transfer process implemented by semiconductor manufacturing equipment  10  uses load lock chambers La and Lb into which a wafer cassette C may be loaded. Each wafer cassette C may contain a plurality of wafers. Opposing doors D 1  and D 2  in load lock chambers La and Lb may be selectively opened or closed to allow loading or unloading of a wafer cassette. In the illustrated embodiment, door D 2  of load lock chambers La and Lb open into a sealed transfer chamber T. Transfer chamber T is typically a clean environment and is routinely fixed with a robot  12  adapted to transfer wafers W or wafer cassettes C from either one of load lock chambers La and Lb to a desired position.  
         [0008]     Transfer chamber T is further adapted to allow transfer of wafers W or wafer cassettes C to any one of a plurality of process chambers (e.g., P 1 , P 2 , P 3 , P 4 ). Respective doors D 3  allow loading and unloading of process chambers P 1 , P 2 , P 3 , P 4 . Further, wafers W or wafer cassettes C may be transferred by means of transfer chamber T and robot  12  to and from a support chamber S. Support chamber S commonly performs a function of consistently aligning the center of a loaded wafer with a set position. This set position may be defined in relation to a wafer flat zone (e.g., a flattened wafer edge).  
         [0009]     Within the wafer transferring process performed by the semiconductor manufacturing equipment  10 , a wafer cassette C holding a plurality of wafers is held at a predetermined position within either one of load lock chambers La and Lb. Robot  12  transfers wafers from a wafer cassette C using a robot chuck  18  supported on robotic arms  16   a  and  16   b.  By means of robotic arms  16   a  and  16   b,  robot chuck  18  may be extended into a wafer cassette C to retrieve a wafer W. Once a wafer W is grasped, robotic chuck  18  may be withdrawn by contraction of robotic arms  16   a  and  16   b.  Then robot chuck  18  may be rotated to face support chamber S. Control of all aspect of robot  12  are conventionally controlled by various control signals provided by a controller (not shown) operating under a defined software routine and/or a human operator&#39;s instruction.  
         [0010]     At this point, robot  12  inserts wafer W into support chamber S. Within support chamber S, a sensor (not shown) is used to-detect the wafer flat zone and properly align the wafer in relation to the flat zone.  
         [0011]     Once properly aligned, wafer W is extracted from support chamber S by robot  12 . Then, robot  12  rotates to face a selected one of the plurality of processing chambers P 1 , P 2 , P 3  and P 4  and loads wafer W therein.  
         [0012]     As described above, wafer W is conventionally aligned in support chamber S before being transferred by robot  12  to a selected process chamber. However, the provision of support chamber S adds considerable size to the foot-print of semiconductor manufacturing equipment  10  within the manufacturing facility. Further, the double transfer requirement (i.e., load lock chamber-to-support chamber-to-process chamber) by robot  12  takes overly long and adversely impacts manufacturing productivity.  
       SUMMARY OF THE INVENTION  
       [0013]     In one embodiment, the invention provides semiconductor manufacturing equipment, comprising; a robot comprising a robotic arm adapted to transfer a wafer from a wafer cassette in a load lock chamber to a processing chamber with proper alignment and positioning without the need to intermediately pass through a support chamber specially adapted to align and position the wafer.  
         [0014]     In another embodiment, the invention provides semiconductor manufacturing equipment, comprising; a plurality of processing chambers adapted to receive a wafer from a central transfer chamber via a robotic arm, a load lock camber holding a wafer cassette, the wafer cassette holding a plurality of wafers, a robot contained within the transfer chamber and comprising a robotic arm adapted to transfer one of the plurality of wafers from a wafer cassette from the load lock chamber to one of the plurality of processing chambers with proper alignment and positioning without the need to intermediately pass through a support chamber specially adapted to align and position the wafer. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a schematic view illustrating conventional semiconductor manufacturing equipment;  
         [0016]      FIG. 2  is a schematic view illustrating a semiconductor manufacturing equipment according to an embodiment of the invention;  
         [0017]      FIG. 3  is a cross-sectional view schematically illustrating sensors taken along line I-l′ in  FIG. 2 ; and  
         [0018]      FIG. 4  is a perspective view illustrating robot transfer within an embodiment of the invention. 
     
    
     DESCRIPTION OF EMBODIMENTS  
       [0019]     Embodiments of the invention will be described with reference to accompanying drawings. However, the invention is not limited to only the illustrated embodiments but may be variously embodied.  
         [0020]      FIG. 2  is a schematic view of semiconductor manufacturing equipment according to an embodiment of the invention. Referring to  FIG. 2 , the disposition of wafer cassette C holding a plurality of wafers W as loaded within load lock chambers La and Lb, as well as the disposition of load lock chambers La and Lb and processing chambers P 1 , P 2 , P 3 , and P 4  to transfer chamber T are similar to the conventional arrangement. Here again, a robot  12  within transfer chamber T transfers wafers W between the various positions discussed above.  
         [0021]     However, door D 2  associated with load lock chambers La and/or Lb is fitted with sensor components  20   a  and  20   b.  In the illustrated embodiment, one sensor component  20   a  is fitted to an upper portion of door D 2  and another sensor component  20   b  is fitted to a lower portion of door D 2 . The sensor formed by sensor components  20   a  and  20   b  may be an optical sensor, such as an infrared sensor.  
         [0022]     As wafer W is unloaded from load lock chamber La or Lb by robot  12  the combination of sensor components  20   a  and  20   b  generate an alignment signal indicative of the wafers orientation as grasped by robot  12 . For example, a light beam (e.g., infrared energy) may be emitted from a first sensor component  20   a  (e.g., a photodiode or laser) and received (or not) by a second sensor component  20   b . That is, when blocked by wafer W the emitted light does not reach second sensor component  20   b.  Second sensor  20   b  (e.g., a photodetector) is adapted to generate the alignment signal and provide to connected controller P (e.g., a PC, laptop or handheld computer). Upon receiving the alignment signal, controller P is able to determine the relative position and alignment of wafer W. For example, controller P may be adapted to detect a center of wafer W in relation to the received alignment signal. Having determined the relative position and alignment of wafer W, controller P is able to control the movement of robot  12 .  
         [0023]      FIG. 3  is a cross-sectional view schematically illustrating sensor components  20   a,    20   b  as positioned along line I-l′ in  FIG. 2 . Referring to  FIG. 3 , when robot  12  unloads wafer W from load lock chamber La or Lb into transfer chamber T, light emitted from first sensor component  20   a  either irradiates second sensor component  20   b  or is blocked by wafer W. The timed presence and absence of the emitted light at second sensor component  20   b,  as indicated by the alignment signal provided by second sensor component  20   b,  allows controller P to determine position and alignment information. Movement of robot  12  may then be made with knowledge of the actual position and alignment information.  
         [0024]      FIG. 4  is a perspective view further illustrating a robot adapted for use in the semiconductor manufacturing equipment according to an embodiment of the invention. Referring to  FIG. 4 , robot  40 , as adapted to transfer wafer W, comprises; a first robot arm  16   a  adapted to rotate around a supporting axis member  22 , a second robot arm  16   b  linked to a vertical hem and adapted to rotate relative to first robot arm  16   a;  and a robot chuck  18  adapted to support wafer W and connected to second robot arm  16   b.    
         [0025]     Robot chuck  18  comprises finger parts  18   a  and  18   b  bracketing a groove  18   c  and adapted to support only an edge portion of wafer W to thereby reduce the contact area between wafer W and robot chuck  18 .  
         [0026]     A guide rail  26  may also be provided as part of robot  40  as a support to a rotating member  30 . Guide rail  26  may be connected to supporting axis member  22 . As a complete assembly, guide rail  26  and robot chuck  18  may cooperate to move wafer W up, down, and around along the length of guide rail  26 . Rotating member  30  may be adapted to fix the under side of wafer W (e.g., with a vacuum pressure) and may be further adapted to fit through groove  18   c  of robot chuck  18 .  
         [0027]     If wafer W is rotated by means of rotating member  30  third and fourth sensor components  32   a  and  32   b  may readily be used to sense the flat zone position of wafer W.  
         [0028]     Additional (third and fourth) sensor components  32   a  and  32   b  may be provided with robot  40 . Various CCD camera components, photocouplers, etc., may be used to implement these sensor components. However implemented, the additional sensor components may be used to sense the flat zone position of wafer W. In this regard, additional sensors  32   a  and  32   b  may be adapted to send a wafer alignment signal to controller P. Here again, controller P, upon receiving the alignment signal from additional sensors  32   a  and  32   b  may used this information to position wafer W using robot arm  16   a,    16   b  and rotating member  30 .  
         [0029]     As illustrated robots  12  and  40  are shown with first and second robot arms that to move in relation to supporting axis member  22 . However, a robot of any reasonable construction might be used (e.g., cantilever arms having a plurality of articulations, etc.).  
         [0030]     When reviewing processes for transferring and aligning the wafer, robot  40  extends and drives robot arm  18  to seat robot chuck  18  against the bottom side of wafer W when wafer W is placed on any predetermined position. Robot  40  goes up and down, and drives supporting axis  22  so that the wafer is placed on the upper side of robot chuck  18 . Accordingly, when wafer W is supported on robot chuck  18 , the robot contracts and drives robot arm  18 . In the process to unload wafer W from wafer cassette C in load lock chamber La or Lb into transfer chamber T using robot chuck  18 , when sensor components  20   a,    20   b  are installed between the load lock chamber La or Lb and transfer chamber T, the position and alignment of wafer W is detected and a corresponding alignment signal is sent to controller P. Then, controller P controls robot  40  to correctly adjust the position and alignment of wafer W.  
         [0031]     Thus, a determination of position and alignment for wafer W is made in relation to a predetermined standard position. For example, a distance and direction between the actual position of the center of wafer W and a standard (e.g., properly seated) position of the center of the wafer W may be used to re-position wafer W using robot  40  and controller P.  
         [0032]     Re-positioning may be accomplished (and/or verified) using additional sensor components  32   a  and  32   b  in conjunction with robot  40 , including rotating member  30 .  
         [0033]     Thus, the process of properly aligning and positioning wafer W is performed entirely without the need for a specialized support chamber S.  
         [0034]     Properly positioned and aligned wafers W may be directly provided from load lock chambers La and Lb to any one of the plurality of process chambers P 1 , P 2 , P 3 , P 4  using robot  40  and controller P. This approach decreases the foot-print of the semiconductor manufacturing equipment and increases wafer throughput.  
         [0035]     It will be apparent to those skilled in the art that modifications and variations can be made in the foregoing without removing such from the scope of the present invention as defined by the following claims.