Abstract:
Method and apparatus are described for a spherical surface inspection system comprising a controller having software, an optical sensor connected to the controller, and an inspection device disposed adjacent to the optical sensor, and connected to the controller. The inspection device is for retaining and rotating the spherical-shaped object along a first axis to allow the optical sensor to convey an image of a portion of the surface of the spherical-shaped object to the controller. The inspection device also rotates the spherical-shaped object along a second axis to convey an image of more of the surface of the spherical-shaped object to the controller.

Description:
This application pertains to an inspection system for the surfaces of spherical-shaped objects. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an inspection system according to the present embodiment. 
     FIG. 2 is a plan view of a portion of a device for rotating a spherical-shaped object according to the system of FIG.  1 . 
     FIGS. 3 a-f  are schematic views of the spherical-shaped object at several points during inspection. 
     FIG. 4 is a schematic view of the inspection path on the spherical-shaped object. 
     FIG. 5 is a perspective view of an alternative embodiment of the inspection system. 
     FIG. 6 is a perspective view of a sleeve and tube according to FIG.  5 . 
     FIG. 7 is a perspective view of an alternative embodiment of a holding arm. 
     FIG. 8 is a perspective view of yet another alternative embodiment of a holding arm. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 depicts a system  10  for allowing inspection of a spherical-shaped object  12 . Although many uses are contemplated for the system  10 , in an illustrative embodiment, the spherical-shaped object  12  is a spherical-shaped semiconductor, the term “semiconductor” being used without consideration for the particular stage of manufacturing or processing steps in which inspection occurs. Generally, a substrate is used to form an orb, and an alignment mark is provided on the surface of the orb. All subsequent lithographic and etching processes are aligned to the alignment mark, and hence to each other, to eventually produce the final product, a spherical-shaped semiconductor integrated circuit. It is desirable to inspect the surface of the semiconductor occasionally during manufacture and processing. 
     An optical sensor  14  is provided for conveying an image of the spherical-shaped object  12 . The optical sensor  14  has a lens  14   a , for example, a conventional 5×, 10×, 20×, 25×, or a 50× objective lens, the power of the lens depending on the desired resolution. The optical sensor  14  is operably connected to a controller  16 , which comprises software and connectors necessary to observe and control manipulation of the spherical-shaped object  12 , in a manner to be explained. 
     An inspection device, generally referred to by the reference numeral  18 , is connected to the controller  16  and retains the spherical-shaped object  12 . The device  18  has a housing  20 , with a motor  22  attached to the housing. The motor  22  produces rotary motion when prompted by the controller  16 . The motor  22  is attached to a stage  24 , which rotates equatorially, as indicated by the reference arrow A. 
     An arm  25  is affixed to the stage  24 , extending outwardly relative to the stage. A retainer  26  is disposed on the arm  25 , and retains a sleeve  28 . A rod  30  is rotatably disposed in the sleeve  28 , as indicated by the reference arrow B. The rod  30  is connected to conventional means for producing the rotation B, such as a small motor (not depicted) disposed in the retainer  26 , arm  25 , or stage  24 , or alternatively, to gears operably connected to the motor  22 . It is understood that the spherical-shaped object  12  may be removably coupled to the rod  30  by any of various means, such as by a vacuum produced in a cavity (not depicted) of the rod to draw the spherical-shaped object to the rod, or by reversibly affixing the spherical-shaped object to the rod. 
     As depicted, the position of the spherical-shaped object  12  is reflected by three illustrative axes, X, Y, and Z. The X axis runs from the center of the stage  24  through the center of the spherical-shaped object  12 . Thus, rotation A is around the X axis. The Y axis runs through the center of the rod  30  and the spherical-shaped object  12 , and thus, rotation B is around the Y axis. The Z axis runs through the center of the lens  14   a  and the spherical-shaped object  12 . Once retained by the rod  30 , the spherical-shaped object  12  moves with the stage  24 , arm  25 , and rod during rotation A. The rod  30  also imparts its rotation B to the spherical-shaped object  12 . 
     The controller  16  controls the amount and sequence of rotation A and the rotation B, and hence respective corresponding rotations of the spherical-shaped object  12 , as will be described. The rotation B may occur simultaneously, or separately, from rotation A above, and a number of rotational ratios (degrees A:degrees B) are contemplated. It is understood that rotation A and rotation B could each occur in two rotational directions, clockwise or counterclockwise. Additionally, the net rotation produced on the spherical-shaped object  12  in the desired rotational direction (rotation A or rotation B) depends on the duration of rotation. 
     For example, and referring now to FIG. 2, the stage  24  may be rotated in rotation A, counterclockwise as depicted from arm position  33   a , to produce a set of illustrative arm positions  33   b-f , shown in phantom, representing an infinite set of possible arm positions. It is understood that each of the arm positions  33   b-f  is produced by a different net rotational duration, increasing respectively, from the arm position  33   a . Alternatively, the rotation A could occur in the opposite direction (clockwise). 
     Each of the arm positions  33   a-f  is associated with a unique orientation of the spherical-shaped object  12  with respect to the Z axis, as illustrated in FIGS. 3 a-f , respectively. More specifically, and referring to FIGS. 3 a-f , the counterclockwise rotation A (FIG. 2) moves the Y axis (aligned with the rod  30 ) in relation the Z axis. Thus, the rotation A (FIG. 2) produces a set of increasing angular displacements α, β, γ, δ, ε, and λ, between the Y and Z axes for the respective positions  33   a-f . For example, as shown in FIG. 3 a , the angular displacement of a (position  33   a  of FIG. 2) is approximately zero degrees. It is understood that the field of view  34  (represented by the dashed circle) of the lens  14   a  (FIG. 1) is normally concentric to the Z axis, and that an angular displacement of approximately zero causes the field of view  34  to be disposed on the surface of the spherical-shaped object  12  concentric to the Y axis as well. 
     Turning to FIG. 3 b , rotation A produces an angular displacement β between the Y and Z axes. A 360° rotation B of the rod  30  will move the field of view  34  in a path of a predetermined area (“loop”)  36   b  around the surface of the spherical-shaped object  12 . Loops for the for the angular displacements α, β, γ, δ, ε, and λ, have been given the reference numerals  36   a-f , respectively, although it is understood that loop  36   a  is equivalent to the field of view  34 . 
     
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Rotation A 
                   
                   
               
               
                 Angular displacement of Y axis 
                 Rotation B 
               
               
                 relative to Z axis 
                 Degrees 
                 Loop 
               
               
                   
               
             
             
               
                 α 
                 — 
                 36a 
               
               
                 β 
                 360° rotation 
                 36b 
               
               
                 γ 
                 360° rotation 
                 36c 
               
               
                 δ 
                 360° rotation 
                 36d 
               
               
                 ε 
                 360° rotation 
                 36e 
               
               
                 λ 
                 360° rotation 
                 36f 
               
               
                   
               
             
          
         
       
     
     The angular displacements α, β, γ, δ, ε, and λ, are selected in a manner to allow the loops  36   a-f  to abut, or alternatively, to overlap, each other, and it is understood that in practice, the number of loops required depends upon the width of the field of view  34  in relation to the surface area of the spherical-shaped object  12  to be covered. 
     In operation, referring to FIG. 4, the controller  16  (FIG. 1) plots and executes a series of combinations for rotations A and B, thereby moving the len&#39;s field of view  34  (FIGS. 3 a-f ) in the loops  36   a-f  over the surface of the spherical-shaped object  12 . As such, the lens  14   a , and hence the controller  16 , observes the surface of the spherical-shaped object  12  disposed in each of the loops  36   a-f.    
     Images of the spherical-shaped object  12  (observed as the loops  36   a-f ) may be stored and/or combined to form a software-generated image of the surface of the spherical-shaped object. The software-generated image may be inspected by a user and/or by software for compliance with accepted appearance standards, such as for particles, scratches, and other defects. The software-generated image may also be manipulated for analysis, such as moved, rotated, or zoomed. Moreover, the spherical-shaped object may retain an identifying area, such as a bar-code, which may be observed as well for identifying the spherical-shaped object  12 . 
     In this manner, the entire surface of the spherical-shaped object  12  may be inspected, with the exception of the portion of the spherical-shaped object coupled to the end of the rod  30 , which is understandably obscured. It is understood that the aforesaid obscured portion could be deemed unnecessary to inspect, or alternatively, the spherical-shaped object  12  could be detached from the rod  30  and recoupled at a different portion of the surface of the spherical-shaped object. 
     Although the rotations A and B have been discussed as occurring discretely for purposes of explanation, it is understood that the rotations A and B could occur incrementally and simultaneously to form a gradual spiral path around the surface of the spherical-shaped object  12 . 
     Referring to FIG. 5, a system  10 ′ is depicted for allowing inspection of the spherical-shaped object  12 . It is understood that the system  10 ′ enjoys some of the same components as the foregoing embodiment of FIGS. 1-4, and thus, the reference numbers associated with those components are retained. 
     An optical sensor  14  is provided for conveying an image of the spherical-shaped object  12 . The optical sensor  14  has a lens  14   a , and is operably connected to a controller  16 , which comprises software and connectors necessary to observe and control manipulation of the spherical-shaped object  12 , in a manner to be explained. 
     An inspection device, generally referred to by the reference numeral  18 ′, is connected to the controller  16  and retains the spherical-shaped object  12 . The device  18 ′ has a housing  20 , with a motor  22  attached to the housing. The motor  22  produces rotary motion when prompted by the controller  16 . The motor  22  is attached to a stage  24 , which rotates equatorially, as indicated by the reference arrow A. 
     An arm  25  is affixed to the stage  24 , extending outwardly relative to the stage. An extension  40  extends from the arm  25  to capture a sleeve  42 . The sleeve  42  is somewhat flexible, but fixed by the extension  40 . A tube  44  is rotatably disposed in the sleeve  42 , as indicated by the reference arrow B. The tube  44  is connected to conventional means for producing the rotation B, such as a small motor (not depicted) disposed in the arm  25  or stage  24 , or alternatively, to gears operably connected to the motor  22 . It is understood that the tube  44  may be lubricated to facilitate the rotation B. As with the foregoing embodiment, the position of the spherical-shaped object  12  is reflected by three illustrative axes, X, Y, and Z. Rotation A is around the X axis, and rotation B is around the Y axis. The Z axis runs through the center of the lens  14   a  and the spherical-shaped object  12 . 
     Referring to FIG. 6, the tube  44  is hollow, having an opening  44   a . It is understood that the spherical-shaped object  12  may be removably coupled to the tube  44  by any of various means, such as by a vacuum produced in the opening  44   a  of the tube to draw the spherical-shaped object to the tube. Returning to FIG. 5, a vacuum producing device (not depicted) is understood to be operably connected to the tube  44  in such an embodiment. 
     Once retained by the tube  44 , the spherical-shaped object  12  moves with the stage  24 , arm  25 , and tube during rotation A. The tube  44  also imparts its rotation B to the spherical-shaped object  12 . The controller  16  controls the amount and sequence of rotation A and the rotation B, and hence respective corresponding rotations of the spherical-shaped object  12 . The rotation B may occur simultaneously, or separately, from rotation A above, and a number of rotational ratios (degrees A:degrees B) are contemplated. It is understood that rotation A and rotation B could each occur in two rotational directions, clockwise or counterclockwise. Additionally, the net rotation produced on the spherical-shaped object  12  in the desired rotational direction (rotation A or rotation B) depends on the duration of rotation. 
     It is understood that the field of view  34  (represented by the dashed circle) of the lens  14   a  is normally concentric to the Z axis. As described in detail for the foregoing embodiment, rotation A produces a set of angular displacements between the Y and Z axes. A 360° rotation B of the tube  44  will then move the field of view  34  in a loop around the surface of the spherical-shaped object  12 . The set of angular displacements are selected to allow the corresponding loops to abut, or alternatively, to overlap, each other. 
     In operation, the controller  16  plots and executes a series of combinations for rotations A and B, thereby moving the len&#39;s field of view  34  in the loops over the surface of the spherical-shaped object  12 . As such, the lens  14   a , and hence the controller  16 , observes the surface of the spherical-shaped object  12 . The images of the surface of the spherical-shaped object  12  observed via the loops may be stored and/or combined, and may be inspected by a user and/or by software for compliance with accepted appearance standards. In this manner, the entire surface of the spherical-shaped object  12  may be inspected, with the exception of the portion of the spherical-shaped object coupled to the end of the tube  44 , which is understandably obscured. It is understood that the aforesaid obscured portion could be deemed unnecessary to inspect, or alternatively, the spherical-shaped object  12  could be detached from the tube  44  and recoupled at a different portion of the surface of the spherical-shaped object. 
     Referring to FIG. 7, a holder, generally referred to by the reference numeral  50 , is depicted for allowing inspection of the spherical-shaped object  12 . The holder  50  has an extension  52  which is understood to connect with the sleeve  28  (FIG. 1) or sleeve  42  (FIG. 5) of the foregoing systems, respectively  10  and  10 ′, and to rotate in rotation B. The extension  52  is attached to a substantially U-shaped bracket  54 , having arms  54   a-b . Openings  55   a-b  are disposed in the bracket arms  54   a-b , respectively, for receiving pins  56   a-b.    
     The pins  56   a-b  have a distance d between the distal ends of the pins, the distance d being adjustable in an axial direction relative to the pins. The pins  56   a-b  capture and retain the spherical-shaped object  12 . It can be appreciated that the pins  56   a-b  could capture spherical objects of varying diameters (not depicted) by appropriately adjusting the distance d between the distal ends of the pins. 
     Once installed in the sleeve of the system  10  or  10 ′, the holder  50  retains the spherical-shaped object  12  to allow inspection of the spherical-shaped object in a manner previously described. 
     Referring to FIG. 8, an alternative embodiment of the holder of FIG. 7, generally referred to by the reference numeral  60 , is depicted for allowing inspection of the spherical-shaped object  12 . The holder  60  has an extension  62  which is understood to connect with the motor  22  (FIGS. 1 and 5) of the foregoing systems, respectively  10  and  10 ′, and to rotate in rotation A. Thus, the stage  24  of the previous embodiments is removed, and hence the associated structure, such as arm  25 , is removed as well. The X axis is aligned with the extension  62  and passes through the center of the spherical-shaped object  12 . 
     The extension  62  is attached to a substantially U-shaped bracket  64 , having arms  64   a-b . Openings  65   a-b  are disposed in the bracket arms  64   a-b , respectively, for receiving pins  66   a-b . The pins  66   a-b  have a distance d between the distal ends of the pins, the distance d being adjustable in an axial direction relative to the pins. The pins  66   a-b  capture and retain the spherical-shaped object  12 , and are rotatable along the Y axis to produce rotation B. At least one of the pins, for example  66   b , is connected to conventional means for producing the rotation B, schematically represented as  68 . It can be appreciated that the pins  66   a-b  could capture spherical objects of varying diameters (not depicted) by appropriately adjusting the distance d between the distal ends of the pins. 
     It is understood that the field of view  34  (represented by the dashed circle) of the lens  14   a  (FIGS. 1 and 5) is normally concentric to the Z axis. As described in detail for the foregoing embodiments, rotation A produces a set of angular displacements between the Y and Z axes. A 360° rotation B of the pins  66   a-b  will then move the field of view  34  in a loop around the surface of the spherical-shaped object  12 . The set of angular displacements are selected to allow the corresponding loops to abut, or alternatively, to overlap, each other. 
     In operation, the controller  16  (FIGS. 1 and 5) plots and executes a series of combinations for rotations A and B, thereby moving the len&#39;s field of view  34  in the loops over the surface of the spherical-shaped object  12 . As such, the lens  14   a , and hence the controller  16 , observes the surface of the spherical-shaped object  12 . The images of the surface of the spherical-shaped object  12  observed via the loops may be stored and/or combined, and may be inspected by a user and/or by software for compliance with accepted appearance standards, as described above, with reference to the foregoing embodiments. 
     It is understood that all spatial references are for the purpose of example only and are not meant to limit the invention. Furthermore, this disclosure shows and describes illustrative embodiments, however, the disclosure contemplates a wide range of modifications, changes, and substitutions. Such variations may employ only some features of the embodiments without departing from the scope of the underlying invention. For example, other means of actuation are possible. Accordingly, any appropriate construction of the claims will reflect the broad scope of the underlying invention.