Patent Publication Number: US-2023154767-A1

Title: Asc process automation device

Description:
TECHNICAL FIELD 
     The present invention relates to a wafer-manufacturing apparatus, and more particularly to an automated ASC process apparatus for performing an ASC process. 
     BACKGROUND ART 
     A single-crystal silicon ingot is generally grown and manufactured through the Czochralski method. This method is a method in which a polycrystalline silicon is melted in a crucible in a chamber, a seed crystal, which is a single crystal, is immersed into the silicon melt, and the seed crystal is slowly pulled up to grow a single-crystal silicon ingot (hereinafter referred to as an “ingot”) having a desired diameter. 
     A single-crystal silicon wafer manufacturing process broadly includes a single-crystal growing process for producing an ingot, a slicing process for slicing the ingot to obtain a thin disc-shaped wafer, an edge grinding process for machining the edge of the wafer obtained through the slicing process in order to prevent cracking and warpage of the wafer, a lapping process for removing damage to the wafer due to mechanical processing in order to improve the flatness of the wafer, a polishing process for mirror-polishing the wafer, and a cleaning process for removing an abrasive or foreign substances adhered to the polished wafer. 
     Meanwhile, the slicing process in which the ingot is cut into wafers is performed using a wire sawing apparatus. 
       FIG.  1    is a view showing the operation of a general wire sawing apparatus. 
     As shown in  FIG.  1   , the wire sawing apparatus  1000  includes a beam B for fixing the upper portion of an ingot IG, an ingot clamp  1100  for clamping the beam B so that the ingot IG is supported so as to be moveable upwards and downwards, a plurality of rollers  1200  and  1300  provided below the ingot clamp  100  so as to be rotatable, a wire W wound around the plurality of rollers  1200  and  1300  so as to be rotatable in forward and reverse directions, and a slurry ejection nozzle (not shown) for ejecting slurry toward the wire W. 
     In the wire sawing apparatus  1000 , slurry is ejected onto the wire W that is moving at a high speed, and the ingot IG descends toward the wire W. In this case, the ingot IG is cut into a plurality of wafers by friction with the slurry adhered to the wire W. 
     When the wire sawing process is completed, an as sliced cleaning (ASC) process, which includes a series of processes of removing foreign substances, such as slurry, oil, or cutting chips, from the wafers and removing the beam B secured to the upper portions of the wafers to separate the wafers, is further performed as a step preceding the above-described edge grinding process. 
     The ASC process is performed by an ASC process apparatus, in which various devices are combined. The ASC process apparatus sequentially performs procedures required for the ASC process, such as cleaning using kerosene (WN-420), loading, ultra cleaning, primary rinsing, secondary rinsing, tertiary rinsing, wafer separation, and unloading. 
     However, many procedures for the ASC process and many connecting sections (progression sections) between the procedures are performed manually, rather than in an automated manner. Such manual labor causes degradation in the quality of the ASC process (generation of stains on the surface of a wafer, non-uniform cleaning, damage to a wafer, or the like) depending on the proficiency level of a worker, and is more time-consuming and expensive. 
     DISCLOSURE 
     Technical Problem 
     Therefore, the present invention provides an ASC process automation apparatus capable of automating respective procedures of an ASC process and connecting sections (progression sections) between the procedures, thereby improving the quality of the ASC process and saving time and expenses. 
     Technical Solution 
     The present invention provides an ASC process automation apparatus including a loading unit configured to allow an ingot subjected to wire sawing to be loaded thereon, a kerosene cleaning unit configured to clean the ingot using kerosene, a pre-cleaning unit configured to pre-clean the ingot, a main cleaning unit configured to clean the ingot multiple times, a wafer separation unit configured to split the ingot into a plurality of wafers, and a conveying unit configured to convey the ingot linearly and move the ingot upwards and downwards while passing by the kerosene cleaning unit, the pre-cleaning unit, the main cleaning unit, and the wafer separation unit. 
     The apparatus may further include a rail unit mounted along the kerosene cleaning unit, the pre-cleaning unit, the main cleaning unit, and the wafer separation unit, and the conveying unit may be mounted to the rail unit. 
     The conveying unit may include a clamping unit configured to clamp the ingot, a linear conveying unit mounted so as to be linearly movable along the rail unit, and an upward/downward conveying unit configured to move the clamping unit upwards and downwards. 
     The clamping unit may include a clamp configured to selectively hold or release two opposite points on the outer circumference of the ingot. 
     The linear conveying unit may include a first motor and a wheel movably mounted to the rail and configured to be rotated by the first motor. 
     The upward/downward conveying unit may include a second motor and a wire coupled to the clamping unit and configured to be adjusted in length by the second motor. 
     The kerosene cleaning unit may include a plurality of kerosene baths, and the ingot may be sequentially immersed into the plurality of kerosene baths by the conveying unit. 
     The pre-cleaning unit may include a pre-cleaning tank and a spray nozzle configured to spray a cleaning liquid to the ingot introduced into the pre-cleaning tank by the conveying unit. 
     The main cleaning unit may include a first bath configured to perform ultra cleaning, a second bath configured to perform a primary rinsing process, a third bath configured to perform a secondary rinsing process, and a fourth bath configured to perform a tertiary rinsing process, and the ingot may be sequentially immersed into the first bath, the second bath, the third bath, and the fourth bath by the conveying unit. 
     The wafer separation unit may include a peeling unit configured to remove a beam adhered to the ingot conveyed by the conveying unit. 
     The peeling unit may include a peeling tank configured to store a liquid for peeling and to allow the ingot to be immersed thereinto and a beam separator configured to separate the beam from the ingot located in the peeling tank. 
     The conveying unit may put the ingot into the peeling tank such that the beam is located on the upper portion of the ingot, the beam separator may remove the beam in the longitudinal direction of the beam at a position above the peeling tank, and the removed beam may be discharged outside by the conveying unit. 
     The apparatus may further include an unloading unit mounted adjacent to the wafer separation unit and configured to discharge the plurality of wafers outside. 
     The unloading unit may include an unloading robot configured to grasp the plurality of wafers and convey the plurality of wafers from the peeling tank. 
     The present invention provides an ASC process automation apparatus including an ingot formed such that a beam is attached to wafers, a conveying unit configured to convey the ingot linearly and move the ingot upwards and downwards, and a rail unit configured to allow the conveying unit to be mounted thereto. The conveying unit includes a clamping unit configured to clamp the ingot, a linear conveying unit mounted so as to be linearly movable along the rail unit, and an upward/downward conveying unit configured to move the clamping unit upwards and downwards. 
     Advantageous Effects 
     According to the ASC process automation apparatus of the present invention, respective procedures of an ASC process and connecting sections (progression sections) between the procedures are automated and thus are capable of being consecutively performed, thereby improving the quality of the ASC process and saving time and expenses. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view showing the operation of a general wire sawing apparatus. 
         FIG.  2    is a front view schematically showing the configuration of an ASC process automation apparatus according to an embodiment of the present invention. 
         FIG.  3    is an enlarged view of the loading unit, the kerosene cleaning unit, and the pre-cleaning unit shown in  FIG.  2   . 
         FIG.  4    is an enlarged view of the main cleaning unit shown in  FIG.  2   . 
         FIG.  5    is an enlarged view of the wafer separation unit and the unloading unit shown in  FIG.  2   . 
     
    
    
     BEST MODE 
     Hereinafter, embodiments will be elucidated via description thereof with reference to the accompanying drawings. In the following description of the embodiments, it will be understood that, when an element such as a layer (film), region, pattern, or structure is referred to as being “on” or “under” another element such as a substrate, layer (film), region, pad, or pattern, it can be “directly” on or under the other element, or can be “indirectly” formed such that an intervening element may also be present. In addition, it will also be understood that the criteria for “on” or “under” is on the basis of the drawing. 
     In the drawings, elements may be exaggerated in size, omitted, or schematically illustrated for convenience in description and clarity. Further, the sizes of elements do not indicate the actual sizes of the elements. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same parts. Hereinafter, embodiments will be described with reference to the accompanying drawings. 
       FIG.  2    is a front view schematically showing the configuration of an ASC process automation apparatus according to an embodiment of the present invention,  FIG.  3    is an enlarged view of the loading unit, the kerosene cleaning unit, and the pre-cleaning unit shown in  FIG.  2   ,  FIG.  4    is an enlarged view of the main cleaning unit shown in  FIG.  2   , and  FIG.  5    is an enlarged view of the wafer separation unit and the unloading unit shown in  FIG.  2   . 
     As shown in  FIGS.  2  to  5   , the ASC process automation apparatus  1  according to the embodiment may include a loading unit  10 , a kerosene cleaning unit  20 , a pre-cleaning unit  30 , a main cleaning unit  40 , a wafer separation unit  50 , and an unloading unit  60 . 
     The loading unit  10  may be configured as a mechanism or a device for introducing an ingot IG (hereinafter, refer to  FIG.  1   ) that has been subjected to wire sawing into the kerosene cleaning unit  20 . The ingot IG supplied through the loading unit  10  has already been cut into a plurality of wafers through a slicing process (a wire sawing process). A beam B (hereinafter, refer to  FIG.  1   ) is in the state of being attached to the upper portions of the wafers by means of an adhesive material such as glue. Hereinafter, an element formed by coupling the beam B to the wafers so as to have the shape of an ingot IG (a cylinder) will be referred to as an “ingot IG”, and an individual sliced element, which is detachably attached to the beam B, will be referred to as a “wafer”. 
     The loading unit  10  may convey the above-described ingot IG from the wire sawing device to introduce the same into the kerosene cleaning unit  20 . In an example, the loading unit  10  may be embodied as a loader  11 , which includes a wheel mounted to the lower portion thereof and a shelf or a jig mounted to the upper portion thereof to support the ingot IG. 
     The ingot IG introduced into the kerosene cleaning unit  20  by the loading unit  10  may be subjected to a kerosene cleaning process by the kerosene cleaning unit  20 . The kerosene cleaning unit  20  may remove alkali oil, which is contained in slurry used in the wire sawing process, from the surface of the wafer. 
     As shown in  FIG.  3   , the kerosene cleaning unit  20  may include a plurality of kerosene baths  21 ,  22 ,  23 , and  24 , into which the ingot IG is sequentially immersed by a conveying unit  100  to be described later. In an example, the number of kerosene baths  21 ,  22 ,  23 , and  24  may be four, but the embodiments are not limited thereto. Different concentrations of kerosene may be stored in the respective kerosene baths  21 ,  22 ,  23 , and  24 . Of course, some of the plurality of kerosene baths  21 ,  22 ,  23 , and  24  may be filled with a cleaning liquid other than kerosene. 
     The ingot IG may be sequentially immersed into the respective kerosene baths  21 ,  22 ,  23 , and  24  for a predetermined amount of time. To this end, the conveying unit  100  may move the ingot IG downwards to immerse the same into one of the kerosene baths  21 ,  22 ,  23 , and  24 , may move the ingot IG upwards, may convey the ingot IG toward another of the kerosene baths  21 ,  22 ,  23 , and  24 , and may then move the ingot IG downwards thereinto. 
     Conventionally, the process of immersing the ingot IG into the kerosene baths  21 ,  22 ,  23 , and  24  is performed manually by a worker. However, according to the present invention, the kerosene bath process may be automated in a manner such that the conveying unit  100  sequentially immerses the ingot IG into the plurality of kerosene baths  21 ,  22 ,  23 , and  24 . 
     The pre-cleaning unit  30  may perform a pre-cleaning process on the ingot IG subjected to kerosene cleaning. 
     The pre-cleaning unit  30  may perform a process for primarily (macroscopically) removing kerosene and foreign substances from the wafer as a step preceding the main cleaning step. Therefore, the pre-cleaning unit  30  may include a forcible and powerful means. 
     For example, as shown in  FIG.  3   , the pre-cleaning unit  30  may include a pre-cleaning tank  300  and a spray nozzle  310  for spraying a cleaning liquid to the ingot IG introduced into the pre-cleaning tank  300  by the conveying unit  100 . 
     The pre-cleaning tank  300  may be provided therein with a fixing means for stably supporting the ingot IG conveyed by the conveying unit  100 . The fixing means may be configured to rotate or move the ingot IG. The spray nozzle  310  may spray the cleaning liquid toward one side surface of the ingot IG, fixed to the fixing means, at a constant pressure. Here, the spray nozzle  310  may be mounted in the pre-cleaning tank  300  so as to be movable upwards and downwards in order to spray the cleaning liquid toward the opposite side surface of the ingot IG. 
     Conventionally, the pre-cleaning process is performed manually by a worker. However, according to the present invention, the pre-cleaning process may be automated in a manner such that the spray nozzle  310  is controlled to spray the cleaning liquid uniformly and stably toward the ingot IG conveyed into the pre-cleaning tank  300  by the conveying unit  100 . 
     The main cleaning unit  40  may perform a process of cleaning the ingot IG multiple times (several times). To this end, the main cleaning unit  40  may include a plurality of baths. 
     For example, as shown in  FIG.  4   , the main cleaning unit  40  may include a first bath  41  for performing ultra cleaning, a second bath  42  for performing a primary rinsing process using DIW, a third bath  43  for performing a secondary rinsing process using DIW, and a fourth bath for performing a tertiary rinsing process using hot DIW (e.g. 80° C.). 
     The ingot IG, which is conveyed by the conveying unit  100 , may be sequentially immersed into the first bath  41  to the fourth bath of the main cleaning unit  40  described above, and thus may be cleaned. 
     As shown in  FIG.  5   , the wafer separation unit  50  may split the ingot IG into a plurality of wafers. To this end, the wafer separation unit  50  may include a peeling unit  500  for removing the beam B from the ingot IG conveyed by the conveying unit  100 . 
     For example, the peeling unit  500  may include a peeling tank  510 , in which a liquid for peeling is stored and into which the ingot IG is immersed, and a beam separator  520  for separating the beam B from the ingot IG located in the peeling tank  510 . 
     The conveying unit  100  may put the ingot IG into the peeling tank  510  such that the beam B is located on the upper portion of the ingot IG, and the beam separator  520  may remove the beam B in the longitudinal direction of the beam B (refer to the y-direction in  FIG.  1   ) at a position above the peeling tank  510 . In this case, the removed beam B may be discharged outside by the conveying unit  100 . 
     Conventionally, in order to separate wafers, a worker immerses the ingot IG into a tank in which a liquid for peeling is stored, and waits for a predetermined time period until an adhesive adhered to the beam B and to the wafers dissolves. Then, the worker needs to manually separate the wafers from the upper portion of the beam B, which leads to damage to the wafers or secondary contamination thereof. 
     In contrast, according to the present invention, the processes of separating and discharging the wafers are performed by the peeling unit  500 , the conveying unit  100 , and the unloading unit  60  without the necessity of any manual labor by a worker, thereby shortening the processing time and improving the quality of the wafer separation process. 
     The unloading unit  60  may be mounted adjacent to the wafer separation unit  50 , and may discharge the plurality of wafers outside. The unloading unit  60  may be embodied as an unloader  600  including an unloading robot configured to grasp the plurality of wafers and convey the same from the peeling tank  510 . In an example, the unloading robot may draw the plurality of wafers all together out of the wafer separation unit  50 , or may individually draw the plurality of wafers one by one out of the wafer separation unit  50 . In this case, a cassette such as a FOUP may also be used. 
     In addition, the present invention may further include the conveying unit  100  and a rail unit  200 . 
     As shown in  FIG.  2   , the conveying unit  100  may convey the ingot IG linearly and may move the same upwards and downwards while consecutively passing by the kerosene cleaning unit  20 , the pre-cleaning unit  30 , the main cleaning unit  40 , and the wafer separation unit  50  described above. 
     The rail unit  200  may be mounted along the kerosene cleaning unit  20 , the pre-cleaning unit  30 , the main cleaning unit  40 , and the wafer separation unit  50 , and the conveying unit  100  may be mounted to the rail unit  200 . In an example, the rail unit  200  may be mounted in the longitudinal direction (the x-axis direction) so as to connect all of the parts of the ASC process apparatus. The rail unit  200  may be embodied as a single rail or a plurality of rails. Accordingly, the conveying unit  100  may move along the rail unit  200  so that the procedures of the ASC process are sequentially performed. 
     In an example, as shown in  FIG.  3   , the conveying unit  100  may include a clamping unit  110 , a linear conveying unit  120 , and an upward/downward conveying unit  130 . 
     The clamping unit  110  may clamp the ingot IG. In an example, the clamping unit  110  may include a clamp  111  configured to selectively hold or release two opposite points on the outer circumference of the ingot IG. Here, as shown in  FIG.  1   , the ingot IG may be disposed such that the longitudinal direction thereof is parallel to the Y-axis direction, and the clamp  111  may selectively hold or release the front and rear points of the ingot IG in the X-axis direction. Accordingly, the ingot IG may be disposed by the conveying unit  100  such that the longitudinal direction thereof is parallel to the Y-axis direction, and may undergo the ASC process in the X-axis direction. 
     The linear conveying unit  120  may be mounted so as to be linearly movable along the rail unit  200 . 
     Although not shown in detail, the linear conveying unit  120  may include a first motor and a wheel movably mounted to the rail and configured to be rotated by the first motor. Accordingly, the wheel may be linearly moved in the forward-backward direction along the longitudinal direction of the rail by rotation of the first motor in forward and reverse directions. 
     The upward/downward conveying unit  130  may move the clamping unit  110  upwards and downwards. 
     Although not shown in detail, the upward/downward conveying unit  130  may include a second motor and a wire coupled to the clamping unit  110  and configured to be adjusted in length by the second motor. Accordingly, the wire may move the clamping unit  110  upwards and downwards in the longitudinal direction of the wire (the Z-axis direction in  FIG.  1   ) in response to rotation of the second motor in forward and reverse directions. 
     As described above, according to the ASC process automation apparatus of the present invention, respective procedures of the ASC process and connecting sections (progression sections) between the procedures are automated and thus are capable of being consecutively performed by the rail unit  200  and the conveying unit, thereby improving the quality of the ASC process and saving time and expenses. 
     The features, structures, effects, and the like described in association with the embodiments above are incorporated into at least one embodiment of the present invention, but are not limited only to the one embodiment. Furthermore, the features, structures, effects, and the like exemplified in association with respective embodiments can be implemented in other embodiments by combination or modification by those skilled in the art. Therefore, contents related to such combinations and modifications should be construed as falling within the scope of the present invention. 
     INDUSTRIAL APPLICABILITY 
     The ASC process automation apparatus according to the embodiment may be used for apparatuses for manufacturing a semiconductor element, a silicon wafer, or the like.