Abstract:
The present invention provides a blade breakage and abrasion detecting device comprising: a detecting unit including a light-emitting unit which is provided close to a side of a blade to emit a round shape light toward the blade, and a light receiving unit which is provided opposed to the light-emitting unit as sandwiching the blade to receive the round shape light from the light-emitting unit with a round shape light receiving area; a moving device which moves the detecting unit toward a rotation center of the blade; and a control unit which detects a breakage of the blade based on a change of an amount of light received by the light receiving unit of the detecting unit, and calculates an abrasion amount of the blade by accumulating a moving amount obtained by controlling the moving device to moves the detecting unit toward the rotation center of the blade.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a blade breakage and abrasion detecting device, and more specifically, the invention relates to the blade breakage and abrasion detecting device which automatically detects a breakage and an abrasion of a blade of a dicing apparatus. 
         [0003]    2. Description of the Related Art 
         [0004]    A dicing apparatus which divides a work having a semiconductor device and an electronic element formed thereon into a chip comprises a blade which is rotated at high speed by a spindle, a table which holds the work with suction, X, Y, Z, and θ axes which are the axes of motion changing a relative position of the table and the blade. The dicing apparatus grooves and cuts the work which is held on the table with suction and is relatively moved by each axis with the blade which rotates at high speed. 
         [0005]    The blade is gradually abraded because of a work load at the blade when the dicing apparatus processes the work, and the blade is broken at the processing when there is a large work load at the blade. A depth of a groove processed with the blade is changed when the processing is continued with the abraded blade, so a grooving process with a predetermined depth and an assured cutting process can not be performed. Also, it becomes a cause of damaging the workpiece that the processing is continued with the broken blade. 
         [0006]    To solve such a problem, a device which detects an amount of an abrasion of a blade by detecting an amount of moving down of the blade when the blade is moved down between a light-emitting unit and a light receiving unit which are provided opposed having a predetermined space in the middle is disclosed in Japanese Patent Application Laid-Open No. 8-164515. In addition, as disclosed in Japanese Patent Application Laid-Open No. 2000-188267, the light-emitting unit and the light receiving unit are provided opposed as sandwiching the rotating blade and the breakage of the blade is detected by detecting the change of the amount of the light received at the light receiving unit. 
         [0007]    However, it is necessary to suspend the processing of the work, move the blade to the abrasion amount detecting device provided the position separated from the table, and move up and down the blade, in order to detect the abrasion amount of the blade with the abrasion amount detecting device of Japanese Patent Application Laid-Open No. 8-164515, thereby a processing efficiency is decreased. The light transmitted to a light-emitting area of the light-emitting unit of a blade breakage detector is small and round at the abrasion amount detecting device of Japanese Patent Application Laid-Open No. 2000-188267, so the peak of the detection sensitivity is narrow with the condition and it is necessary to adjust the height depending on the outstanding length of the blade. 
         [0008]    Therefore, Japanese Patent Application Laid-Open No. 2006-310396 discloses a blade breakage and abrasion detecting device including the light-emitting unit and the light receiving unit provided near by the side of the blade of the dicing apparatus. The light-emitting area of the light-emitting unit and the light receiving area of the light receiving unit have the length equal to or longer than the length of the blade which is outstanding from a flange, and are rectangular shape areas having a longer side toward the rotation center of the blade. 
         [0009]    It is possible to detect the blade breakage and abrasion by detecting the change of the amount of light received with the light receiving area of the light receiving unit according to the blade breakage and abrasion detecting device. At this time, the light-emitting area of the light-emitting unit and the light receiving area of the light receiving unit have the length equal to or longer than the outstanding length of the blade toward the rotation center of the blade, so there is no need to adjust the positions of the light-emitting unit and the light receiving unit according to the outstanding length of the blade. Moreover, there is unnecessary to move the blade to the abrasion amount detecting device because it is possible to calculate the abrasion amount based on the increased amount of the received light. Additionally, it is possible to detect the blade breakage according to the rapid change of the amount of the received light during processing and the abrasion amount of the blade according to the increased amount of the received light even during processing. 
       SUMMARY OF THE INVENTION 
       [0010]    A commonly used blade breakage detecting device includes a light-emitting unit which emits a round shape light to a blade and a light receiving unit which receives the light from the light-emitting unit with a light receiving area with a round shape which is provided opposed to the light-emitting unit with sandwiching the blade. The diameter of the round shaped light receiving area of the light receiving unit is approximately 1 mm. The light receiving unit has a sensitivity which is able to detect a fine partial breakage as small as a square about 0.5 mm on a side. 
         [0011]    However, a flange cover which is attached the blade breakage detecting device on is in a state that the blade breakage detecting device is ordinary watered with a cutting water and a cooling water during cutting. Therefore, there is a time where the fine partial breakage cannot be detected because of the influence of the water. 
         [0012]    There is a case where the fine partial breakage cannot be detected even with the round shape light receiving area, so there are more cases that the blade breakage cannot be detected with the light receiving unit having the rectangular light receiving area like Japanese Patent Application Laid-Open No. 2006-310396 because the detection area becomes larger and the detection sensitivity has blurring (the detection sensitivity becomes lower). 
         [0013]    The present invention has been made in view of the above circumstances and has an object to provide a blade breakage and abrasion detecting device which makes it possible to detect the blade breakage and the abrasion amount at the same time with the detection sensitivity as it stands with eliminating adjusting the position of the detecting unit which has been performed by an operator conventionally. 
         [0014]    To achieve the object above, the present invention provides a blade breakage and abrasion detecting device comprising: a detecting unit including a light-emitting unit which is provided close to a side of a blade to emit a round shape light toward the blade, and a light receiving unit which is provided opposed to the light-emitting unit as sandwiching the blade to receive the round shape light from the light-emitting unit with a round shape light receiving area; a moving device moves the detecting unit toward a rotation center of the blade; and a control unit detecting a breakage of the blade based on a change of an amount of light received by the light receiving unit of the detecting unit, and calculating an abrasion amount of the blade by accumulating a moving amount obtained by controlling the moving device to move the detecting unit toward the rotation center of the blade. 
         [0015]    According to the present invention, the control unit detects the blade breakage based on the amount of light received by the round shape light receiving area of the light receiving unit having a sensitivity of the light receiving as of this date. The, the control unit calculates the abrasion amount of the blade by accumulating the moving amount obtained by controlling the moving device to move the detecting unit toward the rotation center of the blade automatically. 
         [0016]    Thus, according to the present invention, it is possible to detect the blade breakage and the abrasion amount at the same time with keeping the detection sensitivity as it stands with eliminating adjusting the position of the detecting unit which has been performed by an operator conventionally. 
         [0017]    In addition, according to the present invention, the blade breakage and abrasion detecting device is characterized in that the control unit records a first amount of light received by the light receiving unit as a threshold value of the amount of received light, and a second amount of received light which is larger than the first amount of received light. It is preferable that the control unit moves the detecting unit by controlling the moving device toward the rotation center of the blade when the amount of received light by the light receiving unit reaches the second amount of received light, and stops moving the detecting unit by controlling the moving device when the amount of light received by the light receiving unit reaches the first amount of received light during the work processed by the blade. 
         [0018]    According to the present invention, when the amount of light received by the light receiving unit reaches to the second amount of received light during the work processing by the blade, the control unit moves the detecting unit by controlling the moving device toward the rotation center of the blade, and stops moving the detecting unit by controlling the moving device when the amount of received light reaches the first amount of received light. The abrasion amount of the blade can be obtained by accumulating the moving amount. Additionally, the set value of the amount of light received by the light receiving unit with mounting or exchanging the new blade for the old one may be the first amount of received light, but it can be other values smaller than the second amount of received light. 
         [0019]    Moreover, it is preferable that the control unit stops moving the detecting unit by controlling the moving device when the accumulated moving amount of the detecting unit reaches an abrasion limit value which is set beforehand. 
         [0020]    According to the present invention, when the accumulated moving amount of the detecting unit reaches an abrasion limit value which is set beforehand, the control unit stops moving the detecting unit by controlling the moving device so that it is prevented that the detecting unit hits a flange of the blade. 
         [0021]    The blade breakage and abrasion detecting device of the present invention makes it possible to detect the blade breakage and the abrasion amount at the same time with the detection sensitivity as it stands with eliminating adjusting the position of the detecting unit which has been performed by an operator conventionally. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0022]      FIG. 1  is a perspective view showing an exterior of a dicing apparatus which includes a blade breakage and abrasion detecting device of the present embodiment; 
           [0023]      FIG. 2  is a perspective view showing a configuration of a processing unit of the dicing apparatus shown in  FIG. 1 ; 
           [0024]      FIG. 3  is a perspective view of an end of a spindle of the dicing apparatus shown in  FIG. 1 ; 
           [0025]      FIGS. 4A and 4B  are a side view and a cross section view showing typically a configuration of a detecting unit of the blade breakage and abrasion detecting device; 
           [0026]      FIG. 5  is a block diagram showing a composition of the blade breakage and abrasion detecting device; 
           [0027]      FIG. 6  is a graph showing a relation between an abrasion amount of a blade and an amount of a received light; 
           [0028]      FIG. 7  is an explanatory diagram showing a positional relation between the abrasion amount of the blade and a light receiving area; and 
           [0029]      FIG. 8  is a flow chart showing a performance of the blade breakage and abrasion detecting device. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]    Referring to the accompanying drawings, a detailed description will be given below of preferred embodiments of a blade breakage and abrasion detecting device according to the present invention. 
         [0031]      FIG. 1  is a perspective view showing an exterior of a dicing apparatus  1  which includes the blade breakage and abrasion detecting device of the present embodiment. The dicing apparatus  1  comprises a spindle  22 ,  22  having an incorporated high frequency motor, which is provided opposed to each other and having a blade  21  and a wheel cover (not shown) mounted at its end, a processing unit  2  having a work table  31  which holds a work W with suction, a cleaning unit  52  cleaning the processed work W by spinning, a load port  51  loading a cassette storing a number of the works W, a moving device  53  moving the work W, and a control unit  10  controlling integrally a performance of each unit. 
         [0032]    As shown in  FIG. 2 , the processing unit  2  has a X table  33  which is guided by a X guide  34 ,  34  provided on a X base  36  and driven in the X direction shown with X-X in  FIG. 2  by a linear motor  35 , and a work table  31  is provided on the X table  33  through a rotating table  32  which rotates in the θ direction. 
         [0033]    On the other hand, a Y table  41 ,  41  is provided on a side of a Y base  44  which is provided as being stride over the linear motor  35 . The Y table  41 ,  41  is guided by a Y guide  42 ,  42 , and driven by a stepping motor and a ball screw which are not shown in a Y direction shown as Y-Y in the drawing. A Z table  43  which is driven in a Z direction by an unshown driving device is provided at each Y table  41 . Also the spindle  22  with an incorporated high frequency motor having the blade  21  at the end is mounted on the Z table  43 . In this configuration of the processing unit  2 , the blade  21  is index-fed in the Y direction and fed to cut into in the Z direction, and the work table  31  is fed to cut in the X direction. 
         [0034]    The control unit  10  which controls integrally the performance of each unit of the dicing apparatus  1  includes a CPU, a memory, an in/output circuit unit, and various control circuit units, and is incorporated in a mount of the dicing apparatus. 
         [0035]    Next, the configuration of the blade breakage and abrasion detecting device of the present embodiment is described referring to  FIGS. 3 to 4B . 
         [0036]      FIG. 3  is a perspective view showing the configuration of the end of the spindle  22  which includes a detecting unit  3  of the blade breakage and abrasion detecting device and a feeding body  4 , and  FIGS. 4A and 4B  are a side view and a cross section view showing typically the configuration of the detecting unit  3 . 
         [0037]    A wheel cover  23  is provided at the end of the spindle  22  to cover the blade as shown in  FIG. 3 . The wheel cover  23  includes a cover front section  66 , a cover rear section  67 , a nozzle block  65 , and so on. A plurality of hoses  63 ,  64  are connected to the cover rear section  67  and the nozzle block  65 , a cutting water is supplied through the hoses  63 ,  64 , and the supplied cutting water is sprayed from a plurality of nozzles  61 ,  62  to the blade  21  which is rotating. 
         [0038]    As described above, the blade breakage and abrasion detecting device includes the detecting unit  3 , the feeding body  4  and the control unit  10  shown in  FIG. 1 . 
         [0039]    As shown in  FIG. 4A , the detecting unit  3  includes a light-emitting unit  24  and a light receiving unit  25 , and the light-emitting unit  24  and the light receiving unit  25  are attached to the wheel cover  23  in  FIG. 3  with facing each other as sandwiching the blade  21 . The light-emitting unit  24  and the light receiving unit  25  are integrated as the detecting unit  3  and supported to be raised and lowered by a guide block of the wheel cover  23 . In addition, the feeding body  4  which is a moving device of the detecting unit  3  is mounted to the wheel cover  23 , and the detecting unit  3  is moved in the vertical direction of the  FIGS. 3 to 4B  by the drive force of the feeding body  4 . In this manner, a round shape light-emitting area  28  of the light-emitting unit  24  and a light receiving area  29  having a round shape about 1 mm in diameter as shown in  FIG. 4B  are integrally moved straight toward the rotation center S of the blade. A feed screw, a ball screw and so on can be employed as the feeding body  4 . 
         [0040]    An optical cable  26  which is connected to a light source (not shown) with one end is connected the light-emitting unit  24  with another end. The light transmitted from the light source through the optical cable  26  is emitted toward the blade  21  through the round shape light-emitting area  28  formed on the surface of the light-emitting unit  24  facing to the blade  21 . 
         [0041]    On the other hand, an optical cable  27  connected to an amplifier device (not shown) which converts a light signal into an electric signal is connected to the light receiving unit  25  with another end. The light emitted from the light-emitting area  28  of the light-emitting unit  24  is received at the light receiving area  29  having a round shape formed on the light receiving unit  25 , and transmitted to the amplifier device through the optical cable  27 . The transmitted light is converted into the electric signal by the amplifier device and sent to the control unit  10 . The size of the electric signal changes according to the amount of the light received at the light receiving area  29 . 
         [0042]    Next, the function of the blade breakage and abrasion detecting device is explained. 
         [0043]    The dicing apparatus  1  having the blade breakage and abrasion detecting device cuts a work having a semiconductor device and an electronic element formed thereon into a grid state or performs a grooving process with the blade  21  mounted at the end of the spindle  22 . The wheel cover  23  is attached to the spindle  22  as covering the blade  21 , and the cutting water is splayed toward the blade  21  with the nozzle  61 ,  62  which is provided at the wheel cover while the work W is being processed. 
         [0044]    The detecting unit  3  of the blade breakage and abrasion detecting device is attached to the wheel cover  23  so that the light-emitting unit  24  and the light receiving unit  25  sandwich the blade  21  as shown in  FIG. 4A . The round shape light emitted from the light-emitting area  28  of the light-emitting unit  24  is blocked off partially by the blade  21  and received by the round shape light receiving area  29  of the light receiving unit  25 . The received light is converted into the electric signal by the amplifier device (not shown) according to the amount of the received light. 
         [0045]    With the dicing apparatus  1  before starting the work process, it is performed as a calibration process that the rotating blade  21  is slightly touched to the work table  31 , the distance from the origin position of the blade to the work table  31  is recorded, and at the same time, the amount of light received by the light amount area  29  is recorded. The feeding amount to cut into in the Z direction with the blade  21  is adjusted according to the data such as the value obtained by the calibration process, the diameter of the blade  21  which is input beforehand, a work thickness, and a tape thickness. 
         [0046]    The process of the work W is started after finishing the calibration process. The control unit  10  monitors the change of the amount of received light at the light receiving area  29  as the change of the electric signal transmitted from the amplifier device continually. The control unit  10  determines that the blade  21  is broken, when the electric signal is rapidly changed, or when the signal which shows that the amount of received light is larger than the other part is periodically generated. Then, the control unit  10  stops the rotation of the blade, and raises the spindle  22 . In this way, the blade breakage and abrasion detecting device of the present embodiment is able to detect the breakage of the blade  21 . 
         [0047]    By the way, the control unit  10  controls the feeding body  4  according to the change of the amount of light received by the light receiving unit  25  to feed the detecting unit  3  toward the rotation center of the blade automatically. Then, the control unit  10  calculates the abrasion amount of the blade  21  by accumulating the moving amount of the detecting unit  3 . 
         [0048]    Specifically, the control unit  10  records a first amount of received light as a threshold value of the amount of light received by the light receiving unit  25  (for example, 10% of the light receiving area), and a second amount of received light (for example, 60% of the light receiving area) which is larger than the first amount of received light. 
         [0049]    As shown in the graph of  FIG. 6 , when the amount of light received by the light receiving area  29  of the light receiving unit  25  is set 10% at a process start point A 1  (as shown as A 1  in  FIG. 7 ), the detector (the detecting unit)  3  is moved to the position of the set value as the detection started by the automatic feeding body  4 . After that, the processing of the work W by the blade  21  is started, and then the blade  21  abrades away gradually because of the work load on the work W so that makes the diameter smaller. 
         [0050]    The blade  21  is changed by an operator (referring to  FIG. 8  (S 3 )) when the detecting unit  3  detects the breakage of the blade  21  as described above during the processing with the blade  21  (referring to  FIG. 8  (S 2 )). 
         [0051]    On the other hand, the control unit  10  controls the feeding body  4  to feed the detecting unit  3  toward the rotation center of the blade automatically, when the process is continued without having the breakage of the blade  21  and the amount of light received by the light receiving unit  25  with the light receiving area  29  becomes 60% (referring to  FIG. 6  (A 2 ),  FIG. 7  (A 2 ), and  FIG. 8  (S 4 )). Then, the control unit  10  controls the feeding body  4  to stop moving the detecting unit  3  when the amount of light received by the light receiving area  29  becomes 10% (referring to  FIG. 6  (A 3 ),  FIG. 7  (A 3 ), and  FIG. 8  (S 5 )). Specifically, the control unit  10  controls the feeding body  4  to move the detecting unit  3  to the position of the set value as the detection started (referring to  FIG. 8  (S 1 )) because the blade  21  is not broken or the abrasion amount is not reached to an abrasion limit value which is set beforehand (referring to  FIG. 8  (S 5 )). The process of the work W is continuing during the period above. 
         [0052]    The control unit  10  controls the feeding body  4  to feed the detecting unit  3  toward the rotation center of the blade automatically when the amount of light received by the light receiving area  29  becomes 60% in accordance with the abrasion of the blade  21  (referring to  FIG. 6  (A 4 ) and  FIG. 7  (A 4 )). As the amount of light received by the light receiving area  29  becomes 10% (referring to  FIG. 6  (A 5 ) and  FIG. 7  (A 5 )), the control unit  10  controls the feeding body  4  to stop moving the detecting unit  3 . The control unit  10  calculates the abrasion amount of the blade  21  by accumulating the moving amount of the detecting unit  3  at moving repeatedly, and displays the abrasion amount on a display device (not shown in the drawings). 
         [0053]    The control unit  10  controls the feeding body  4  to stop moving the detecting unit  3  and controls an alarm  6  (shown in  FIG. 5 ) to issue an alert to change the blade when the accumulated moving amount of the detecting unit  3  reaches the abrasion limit value which is set beforehand (referring to  FIG. 8  (S 6 )). Then, the operator changes the blade  21  ( FIG. 8  (S 3 )). 
         [0054]    Therefore, a failure that the detecting unit  3  hits a flange  68  of the blade  21  which resulted from an overrun of the detecting unit  3  can be prevented by stopping the detecting unit  3  mandatorily. Additionally, the set value of the amount of light received by the light receiving unit  25  with mounting or exchanging the new blade  21  for the old one may be the first amount of received light, but it can be other values smaller than the second amount of received light. 
         [0055]    As explained above, the blade breakage and abrasion detecting device of the present embodiment makes it possible to detect the blade breakage and the abrasion amount at the same time with the detection sensitivity as it stands with eliminating adjusting the position of the detecting unit  3  which has been performed by the operator conventionally. 
         [0056]    The light-emitting area  28  and the light receiving area  29  has round shape in the present embodiment but they can be square having an area nearly equal to the light-emitting area  28  and the light receiving area  29 .