Patent Publication Number: US-2011062216-A1

Title: Method for manufacturing semiconductor device and bonding apparatus

Description:
The application is based on Japanese patent application No. 2009-215400, the content of which is incorporated hereinto by reference. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a method for manufacturing a semiconductor device and a bonding apparatus. 
     2. Related Art 
     In processes of manufacturing semiconductor devices, wire bonding is performed so as to connect a pad of a semiconductor element and a lead over a substrate. 
     In order to bond a metal wire to the pad of the semiconductor element, first, the tip end of the metal wire inserted through a capillary of a bonding apparatus is melted by electric discharge or the like to form a ball (see Japanese Published patent application A-H07-022456). The ball is bonded to the pad of the semiconductor element heated to a predetermined temperature. In this case, bonding is carried out while applying load and ultrasonic wave to the ball (see Japanese Unexamined patent publication NO. 2000-223526). As materials of the metal wire, gold alloy, copper alloy, and the like are used. Then, as a similar to the process of wire bonding, there is a die bonding process (see Japanese Unexamined patent publication NOS. 2006-278888 and 2005-039096). 
     The bonding process generally has a problem in that the collapse profiles of the balls bonded to the pad of the semiconductor element vary greatly from ball to ball. When the amount of collapse of the balls is small, bonding defects are apt to occur between the wire and the pad of the semiconductor element. On the other hand, when the amount of collapse of the balls is large, the balls become flat and there is a possibility that adjacent balls come into contact with each other. 
     As a result of investigation, the present inventor found that contamination of the capillary during the repeated bonding process and insufficient transmission of the ultrasonic wave to the balls are the causes of the variation in the ball collapse profile. It was also found that a package structure is the cause of the variation in the ball collapse profile. 
     However, method of correcting parameter of work positioning stage device is disclosed (see Japanese Published patent application A-H06-236904), hitherto it was difficult to easily grasp the exact quantitative information on the ball collapse profile in situ (during the bonding operation). Therefore, was not possible to recognize troubles associated with changes with time in the bonding tool, and the yield of the semiconductor device was deteriorated. 
     SUMMARY 
     In one embodiment, there is provided a method for manufacturing a semiconductor device, comprising: 
     detecting a first position over the Z axis of a capillary to move a capillary, through which a wire including a ball formed at a tip end is inserted, along a direction of a Z axis which is an axis in an up-down direction so that the ball comes into contact with a semiconductor devices; 
     detecting a second position over the Z axis of the capillary to apply a load, an oscillation output of an ultrasonic wave and ultrasonic wave vibration to the ball at a tip end of the capillary, and to perform thus bonding; 
     grasping a collapse amount of the ball which is a difference between the first position and the second position and a bonding time taken to complete movement from the first position to the second position; 
     grasping a ball collapse amount for a predetermined period or a bonding time corresponding to a predetermined ball collapse amount from the collapse amount of the ball and the bonding time; 
     determining whether or not the ball collapse amount for a predetermined period or the bonding time corresponding to a predetermined ball collapse amount is within a predetermined numerical range; and 
     adjusting at least one of the load applied to the ball and an oscillation output amount of the ultrasonic wave, which are bonding conditions, when it is determined in the step of determining that the ball collapse amount or the bonding time corresponding to a predetermined ball collapse amount is not within the predetermined numerical range. 
     According to the above embodiment, the ball collapse amount for a predetermined period or the bonding time corresponding to a predetermined ball collapse amount is grasped, and if the ball collapse amount for a predetermined period or the bonding time corresponding to a predetermined ball collapse amount is outside the predetermined numerical range, the bonding conditions are adjusted so that the ball collapse amount for a predetermined period or the bonding time corresponding to a predetermined ball collapse amount falls within the predetermined numerical range. 
     By adjusting the bonding conditions so that the ball collapse amount for a predetermined period or the bonding time corresponding to a predetermined ball collapse amount falls within the predetermined numerical range, it is possible to control the collapse speed of the ball so as to be within a predetermined range. 
     By controlling the collapse speed of the ball so as to be within the predetermined range, it is possible to maintain a uniform ball collapse profile. 
     In addition, in order to maintain a uniform ball collapse profile, a method of adjusting only the bonding time may be considered. For example, a method may be considered in which the bonding time is extended until the ball collapse amount reaches a predetermined amount if the collapse speed of the ball is decreased from that in the initial state where the bonding starts. 
     However, if the bonding time is extended too much, it may have a great influence on the yield of the semiconductor device. 
     In contrast, according to the above embodiment of the present invention, as described above, since the collapse speed of the ball can be controlled so as to be within a predetermined range, it is possible to maintain a constant ball collapse profile without greatly extending the bonding time. 
     The present invention may be embodied as a bonding apparatus for manufacturing a semiconductor device in addition to the method for manufacturing a semiconductor device. 
     In another embodiment, there is provided a bonding apparatus, performing bonding, which includes a capillary, through which a wire including a bonding ball formed at a tip end is inserted, and in which after the ball at a tip end of the capillary is brought into contact with a semiconductor device, a load is applied to the ball, and an ultrasonic wave is oscillated and output to apply an ultrasonic wave vibration to the ball, 
     the capillary moves along a direction of a Z axis which is an axis in an up-down direction so that the ball comes into contact with the semiconductor device, and the bonding apparatus comprising: 
     a storage unit that stores the load applied to the ball and an oscillation output amount of the ultrasonic wave which are bonding conditions of the ball; 
     a detection unit that detects a first position over the Z axis of the capillary by moving the capillary along the Z-axis direction so as to make contact with the semiconductor device, and detects a second position over the Z axis of the capillary when the ball at the tip end of the capillary is bonded by applying a load and an ultrasonic wave vibration to the ball based on the bonding conditions stored in the storage unit; 
     a calculation unit that grasps a collapse amount of the ball which is a difference between the first position and the second position detected by the detection unit and a bonding time taken to complete movement from the first position to the second position and calculates a collapse amount of the ball for a predetermined period or a bonding time corresponding to a predetermined ball collapse amount from the collapse amount of the ball and the bonding time; and 
     a first adjustment unit that adjusts at least one of the load applied to the ball and the oscillation output amount of the ultrasonic wave which are the bonding conditions stored in the storage unit when the collapse amount of the ball for the predetermined period or the bonding time corresponding to the predetermined ball collapse amount calculated by the calculation unit is not within a predetermined numerical range. 
     According to the embodiments of the present invention, a method for manufacturing a semiconductor device and a bonding apparatus capable of maintaining a constant ball collapse profile without greatly affecting the yield of the semiconductor device are provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, advantages and features of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  shows a block diagram of a bonding apparatus according to a first embodiment of the present invention; 
         FIG. 2  shows a method of forming a ball at a tip end of a capillary; 
         FIG. 3  shows the relationship between a bonding time and a ball collapse amount; 
         FIG. 4  shows a block diagram of a bonding apparatus according to a second embodiment of the present invention; 
         FIG. 5  shows the relationship between a bonding time and a ball collapse amount; 
         FIG. 6  shows a block diagram of a bonding apparatus according to a third embodiment of the present invention; and 
         FIG. 7  shows the relationship between the applied power of an ultrasonic wave and the bonding count. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will be now described herein with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes. 
     Hereinafter, embodiments of the present invention will be described based on the drawings. 
     First Embodiment 
     First, an overview of a bonding apparatus of the present embodiment will be described. 
     As shown in  FIG. 1 , a bonding apparatus  1  of the present embodiment includes a capillary  11  through which a wire W having a bonding ball  12  formed at a tip end is inserted. The ball  12  is brought into contact with a pad P of a semiconductor element (semiconductor device) S heated to a predetermined temperature by a heater (not shown) that is laid on a table T. Thereafter, the ball  12  is bonded to the pad P by applying a load and an ultrasonic wave to the ball  12 . Subsequently, the other end of the wire W is bonded to a lead (not shown) of a substrate M similarly by applying a load and an ultrasonic wave to the other end of the wire W. In this way, the pad P of the semiconductor element S is electrically connected to the lead of the substrate M. The present invention is useful for such a wire bonding process, and particularly, for achieving stable bonding of the pad P of the semiconductor element S and the ball  12 . Hereinafter, the bonding of only the semiconductor element S side will be described, and the present invention is also useful for performing bonding of the substrate M side. 
     The capillary  11  moves along the direction of a Z axis which is an axis in the up-down direction (perpendicular direction) so as to bring the ball  12  into contact with the pad P of the semiconductor element S. 
     The bonding apparatus  1  includes a storage unit  13 , a detection unit  14 , a calculation unit  15 , and a first adjustment unit  16 . The storage unit  13  stores bonding conditions of the ball  12 . The detection unit  14  moves the capillary  11  along the Z-axis direction to bring the ball  12  formed at the tip end of the wire W inserted through the capillary  11  into contact with the pad P of the semiconductor element S and detects a first position on the Z axis of the capillary  11 . The detection unit  14  detects a second position on the Z axis of the capillary  11  when the capillary  11  is bonded to the ball  12  by applying a load and an ultrasonic wave to the ball  12  based on the bonding conditions stored in the storage unit  13 . The calculation unit  15  calculates a collapse amount of the ball  12  which is a difference between the first position and the second position detected by the detection unit  14  and a bonding time taken to complete the movement from the first position to the second position. The calculation unit  15  calculates a collapse amount of the ball  12  for a predetermined period or a bonding time corresponding to a predetermined collapse amount of the ball  12  from the calculated collapse amount of the ball  12  and the calculated bonding time. If the collapse amount of the ball  12  for a predetermined period, or the bonding time corresponding to a predetermined collapse amount of the ball  12 , calculated by the calculation unit  15  is outside a predetermined numerical range, the first adjustment unit  16  adjusts the bonding conditions so that the collapse amount of the ball  12  for a predetermined period, or the bonding time corresponding to a predetermined collapse amount of the ball  12  falls within the predetermined numerical range. If the collapse amount of the ball  12  for a predetermined period, or the bonding time corresponding to a predetermined collapse amount of the ball  12  is within the predetermined numerical range, the first adjustment unit  16  does not adjust the bonding conditions. 
     Next, the bonding apparatus  1  will be described in detail. 
     The bonding apparatus  1  includes a supporting member  17  that supports the capillary  11 , a driving unit  18 , a drive control unit  19 , and a timer unit  20 , in addition to the above-described capillary  11 , storage unit  13 , detection unit  14 , calculation unit  15 , and first adjustment unit  16 . 
     The capillary  11  is configured such that the wire W is inserted therethrough, and the tip end of the wire W protrudes from the tip end. The capillary  11  is supported by the supporting member  17 . The supporting member  17  is driven along the X, Y, and Z-axis directions whereby the capillary  11  is also driven. In this specification, the Z-axis direction is the axis in the perpendicular direction (axis vertical to the semiconductor element S), and the X and Y-axis directions are the axes in the horizontal direction. 
     The driving unit  18  drives the supporting member  17 . The driving unit  18  includes motors  181  ( 181 X,  181 Y, and  181 Z) for driving the supporting member  17  in the X, Y, and Z-axis directions and an ultrasonic vibrator  182 . 
     The ultrasonic vibrator  182  is a piezoelectric device, for example. When a voltage is applied to the ultrasonic vibrator  182 , the ultrasonic vibrator  182  oscillates and outputs an ultrasonic wave vibration. The ultrasonic wave vibration is transmitted to the capillary  11  through the supporting member  17 . 
     The drive control unit  19  controls the driving of the driving unit  18 . Specifically, the drive control unit  19  includes a first control unit  191  for controlling the driving of the motors  181  and a second control unit  192  for controlling the driving of the ultrasonic vibrator  182 . 
     The drive control unit  19  controls the driving unit  18  based on the bonding conditions stored in the storage unit  13 . Specifically, the drive control unit  19  moves the capillary  11  to a predetermined position (for example, the central position of the pad P of the semiconductor element S and a predetermined position of the lead (not shown) of the substrate M) based on the X and Y coordinates stored in the storage unit  13 . Similarly, the drive control unit  19  drives the motor  181 Z based on the load conditions stored in the storage unit  13  to control the load applied to the ball  12  at the time of performing bonding. 
     Moreover, the drive control unit  19  controls the ultrasonic vibrator  182  based on the ultrasonic output power stored in the storage unit  13 . 
     Furthermore, the drive control unit  19  controls the driving of the ultrasonic vibrator  182  and the motor  181 Z based on the bonding time which is taken to complete the movement from the first position to the second position and is stored in the storage unit  13 . 
     The detection unit  14  detects the position on the Z axis of the capillary  11 . Specifically, the detection unit  14  detects the position on the Z axis of the capillary  11  using an encoder attached to the motor  181 Z. The detection unit  14  is configured to always detect the position of the capillary  11  at the time of performing bonding. However, the driving unit  14  may be configured to detect at least the first position on the Z axis of the capillary  11  when the ball  12  comes into contact with the pad P of the semiconductor element S and the second position on the Z axis of the capillary  11  when the ball  12  at the tip end of the wire W inserted through the capillary  11  is bonded to the pad P by applying a load and an ultrasonic wave thereto. 
     It should be noted that the positions in the X and Y-axis directions of the capillary  11  may be detected by the detection unit  14 . 
     The calculation unit  15  calculates the collapse amount of the ball  12  for a predetermined period. The calculation unit  15  grasps the collapse amount of the ball  12  which is a difference between the first position and the second position detected by the detection unit  14  and the bonding time taken to complete the movement from the first position to the second position. Moreover, the calculation unit  15  calculates the collapse amount of the ball  12  for a predetermined period from the calculated collapse amount of the ball  12  and the calculated bonding time. It should be noted that as the ball collapse amount for a predetermined period, a collapse speed (μm/s) of the ball  12  may be calculated, and alternatively, a collapse amount of the ball  12  for a given fixed period (for example, 10 ms) may be calculated. 
     The first adjustment unit  16  adjusts the bonding conditions stored in the storage unit  13 . 
     The first adjustment unit  16  determines whether or not the collapse amount of the ball  12  for a predetermined period calculated by the calculation unit  15  is within a predetermined numerical range. If the collapse amount of the ball  12  for a predetermined period calculated by the calculation unit  15  is determined to be outside the predetermined numerical range, the first adjustment unit  16  adjusts the bonding conditions stored in the storage unit  13 . That is, the collapse amount of the ball  12  for a predetermined period is adjusted so as to fall within the predetermined numerical range. 
     On the other hand, if the collapse amount of the ball  12  for a predetermined period calculated by the calculation unit  15  is determined to be within the predetermined numerical range, the first adjustment unit  16  does not adjust the bonding conditions stored in the storage unit  13 . 
     Next, a method for manufacturing a semiconductor device using the bonding apparatus  1  will be described. 
     First, an overview of the method for manufacturing a semiconductor device will be described. 
     A method of manufacturing a semiconductor device according to the present embodiment includes: a step of moving the capillary  11 , through which the wire W having the ball  12  formed at the tip end is inserted, along the direction of the Z axis which is the axis in the up-down direction so that the ball  12  comes into contact with the pad P of the semiconductor element S and detecting the first position on the Z axis of the capillary  11 ; 
     a step of applying a load and an ultrasonic wave to the ball  12  at the tip end of the capillary  11  so as to achieve bonding; 
     a step of detecting the second position on the Z axis of the capillary  11  when bonding is achieved; 
     a step of grasping the collapse amount of the ball  12  which is the difference between the first position and the second position and the bonding time taken to complete the movement from the first position to the second position; and 
     a step of grasping the collapse amount of the ball  12  for a predetermined period from the calculated collapse amount of the ball  12  and the calculated bonding time. 
     If the collapse amount of the ball  12  for a predetermined period is outside the predetermined numerical range, the bonding conditions are adjusted so that the collapse amount of the ball  12  for a predetermined period falls within the predetermined numerical range. If the collapse amount of the ball  12  for a predetermined period is within the numerical range, the bonding conditions are not adjusted. 
     Next, the method for manufacturing a semiconductor device according to the present embodiment will be described in detail. 
     First, the substrate M having the semiconductor element S attached thereto is placed on the table T (step S 1 ). 
     Subsequently, the positions in the X and Y-axis directions of the capillary  11  relative to the semiconductor element S are fixed (step S 2 ). 
     After that, the capillary  11  is lowered towards the semiconductor element S side so that the ball  12  comes into contact with the pad P of the semiconductor element S (step S 3 ). 
     The ball  12  is formed in such a way that after the other end of the wire W is bonded to the lead (not shown) of the substrate M, the wire W is ripped off, and a spark lot L is moved close to the tip end of the wire W protruding from the capillary  11  as shown in  FIG. 2  to apply a high voltage to the tip end to cause a spark discharge (depicted by symbol H in  FIG. 2 ). 
     Subsequently, bonding is performed based on the bonding conditions stored in the storage unit  13  (step S 4 ). The first control unit  191  of the drive control unit  19  drives and controls the motor  181 Z that controls the position on the Z axis of the capillary  11  based on the load stored in the storage unit  13  so as to apply a load to the ball  12 . The second control unit  192  drives the ultrasonic vibrator  182  based on the vibration conditions of the ultrasonic vibrator stored in the storage unit  13  so as to apply an ultrasonic wave vibration to the ball  12 . 
     In this way, the ball  12  is bonded to the pad P of the semiconductor element S. 
     The position on the Z axis of the capillary  11  is detected by the detection unit  14  when the bonding apparatus  1  is operating. 
     The calculation unit  15  calculates the ball collapse amount from the position of the capillary  11  detected by the detection unit  14  (step S 5 ). Specifically, the calculation unit  15  calculates the ball collapse amount from the Z-axis position (first position) of the capillary  11  when the capillary  11  is lowered towards the semiconductor element S side so that the ball  12  comes into contact with the pad P of the semiconductor element S (the bonding start time) and the Z-axis position (second position) of the capillary  11  when the ball  12  is bonded by applying a load and an ultrasonic wave vibration thereto (the bonding end time). Here, the bonding end time means the time at which the time elapsed from the bonding start time reaches the load and ultrasonic wave application time stored in the storage unit  13 . 
     The calculation unit  15  calculates the ball collapse amount for a predetermined period, in this embodiment, for a period from the start to end of the bonding, based on the bonding time stored in the storage unit  13  and the difference between the first position and the second position (step S 6 ). 
     Subsequently, the first adjustment unit  16  acquires the results of the calculation by the calculation unit  15  and determines whether or not the collapse amount of the ball  12  for a predetermined period calculated by the calculation unit  15  is within the predetermined numerical range (step S 7 ). 
     If the collapse amount of the ball  12  for a predetermined period calculated by the calculation unit  15  is determined to be outside the predetermined numerical range, the first adjustment unit  16  adjusts the bonding conditions stored in the storage unit  13  (step S 8 ). That is, the collapse amount of the ball  12  for a predetermined period is adjusted so as to fall within the predetermined numerical range. 
     For example, as shown in  FIG. 3 , when bonding is started by the bonding apparatus  1 , as shown by curve A, the collapse speed of the ball  12  is high, and the ball collapse amount for a predetermined period t 1  is x 1 . However, when the bonding is repeated, the collapse speed of the ball  12  may decrease, and as shown by curve B, the collapse amount of the ball  12  for a predetermined period t 1  may become x 2  which is outside the predetermined numerical range. 
     In this case, the first adjustment unit  16  may increase the ultrasonic power (the output amount of ultrasonic wave) among the bonding conditions stored in the storage unit  13  so that the collapse amount of the ball  12  for a predetermined period falls within the predetermined numerical range. Regarding the amount of increase in the ultrasonic power, the first adjustment unit  16  may grasp the amount of deviation of the ball collapse amount for a predetermined period from the predetermined numerical range and set the amount of increase in the ultrasonic power in accordance with the amount of deviation. Specifically, the amount of deviation (not shown) of the ball collapse amount for a predetermined period from the predetermined numerical range and the amount of increase in the ultrasonic power may be stored in the storage unit  13 , and the first adjustment unit  16  may increase the ultrasonic power based on the data stored in the storage unit  13 . 
     A load may be increased without being limited to the ultrasonic power. In this case, the first adjustment unit  16  may grasp the amount of deviation of the collapse amount of the ball  12  for a predetermined period from the predetermined numerical range and increase the load in accordance with the amount of deviation. 
     Both the ultrasonic power and the load may be adjusted. 
     If the collapse speed of the ball  12  is too high, the first adjustment unit  16  may grasp the amount of deviation of the ball collapse amount for a predetermined period from the predetermined numerical range and adjust the bonding conditions (at least one of the ultrasonic power and the load) in accordance with the amount of deviation. 
     By doing so, it is possible to form balls having a desired shape without greatly changing the bonding time when performing wire bonding later. 
     On the other hand, if the collapse amount of the ball  12  for a predetermined period calculated by the calculation unit  15  is determined to be within the predetermined numerical range, the bonding conditions stored in the storage unit  13  are not adjusted (step S 9 ). 
     By the above-described steps, the bonding of the pad P of the semiconductor element S and the wire W (the ball  12 ) is completed. Subsequently, the lead (not shown) on the substrate M on which the semiconductor element S is formed is bonded to the wire held by the capillary  11  (step S 10 ). 
     The step wherein the collapse amount of the ball  12  for a predetermined period is calculated, and the first adjustment unit  16  determines whether or not the bonding conditions stored in the storage unit  13  will be adjusted and adjusts the bonding conditions as necessary may be performed whenever wire bonding is executed on all of the pads and may be performed at intervals of a predetermined wire-bonding count. 
     Next, the operational effects of the present embodiment will be described. 
     In the present embodiment, the collapse amount of the ball  12  for a predetermined period is grasped, and if the collapse amount of the ball  12  for a predetermined period is outside the predetermined numerical range, the bonding conditions are adjusted so that the collapse amount of the ball  12  for a predetermined period falls within the predetermined numerical range. 
     By adjusting the bonding conditions so that the collapse amount of the ball  12  for a predetermined period falls within the predetermined numerical range, the collapse speed of the ball  12  can be controlled so as to be within a predetermined range. 
     By controlling the collapse speed of the ball  12  so as to be within the predetermined range, it is possible to maintain a uniform ball collapse profile without greatly changing the bonding time. 
     In addition, in order to maintain a uniform ball collapse profile, a method of adjusting the bonding time rather than adjusting the ultrasonic power, the load, or the like may be considered. 
     For example, a method may be considered in which the bonding time is extended if the ball collapse amount is smaller than a predetermined collapse amount, whereas the bonding time is reduced if the ball collapse amount is larger than a predetermined collapse amount. 
     However, this method has the following problems. 
     If the bonding time is extended too much, it may have a great influence on the yield of the semiconductor device. 
     Moreover, if the ball collapse amount is much larger than the predetermined collapse amount, that is, if the balls collapse quickly, it is difficult to shorten the bonding time, and there is a possibility that it will not be possible to control the ball collapse profile. 
     In contrast, in the present embodiment, the collapse amount of the ball  12  for a predetermined period is adjusted by one or both of the load and the ultrasonic power (a combination of the load and the ultrasonic power). Therefore, it is possible to prevent a decrease in the yield of the semiconductor device without greatly changing the bonding time. Moreover, even if balls collapse quickly, by adjusting the bonding conditions to adjust the collapse amount of the ball  12  for a predetermined period, it is possible to control the ball collapse profile. 
     Second Embodiment 
     A second embodiment of the present invention will be described with reference to  FIG. 4 . 
     A bonding apparatus  2  of the present embodiment includes the capillary  11 , storage unit  13 , detection unit  14 , supporting member  17 , driving unit  18 , and drive control unit  19  which are the same as those of the above embodiment. The bonding apparatus  2  further includes a calculation unit  25 , a first adjustment unit  26 , a second adjustment unit  30 , and a timer unit  20  which are different from those of the above embodiment. 
     The second adjustment unit  30  adjusts the bonding time stored in the storage unit  13  so that bonding is performed (the load and the ultrasonic wave are applied to the ball  12 ) until the difference between the first position and the second position of the capillary  11  detected by the detection unit  14  reaches a predetermined value. The second adjustment unit  30  adjusts only the bonding time but does not adjust other bonding conditions. 
     The calculation unit  25  calculates a bonding time corresponding to a predetermined collapse amount of the ball  12 . 
     The calculation unit  25  grasps the collapse amount of the ball  12  (the difference between the first position and the second position detected by the detection unit  14 ) and the bonding time taken to complete the movement from the first position and the second position. Moreover, the calculation unit  25  calculates a bonding time corresponding to a predetermined collapse amount of the ball  12  from the collapse amount of the ball  12  and the bonding time. 
     In this example, since the bonding is performed until the difference between the first position and the second position reaches a predetermined value, the bonding time corresponding to a predetermined ball collapse amount may be a bonding time corresponding to the difference between the first position and the second position. 
     The first adjustment unit  26  adjusts the bonding conditions stored in the storage unit  13 . 
     The first adjustment unit  26  determines whether or not the bonding time corresponding to the predetermined ball collapse amount calculated by the calculation unit  25  is within a predetermined numerical range. If the bonding time corresponding to the predetermined ball collapse amount calculated by the calculation unit  25  is determined to be outside the predetermined numerical range, the first adjustment unit  26  adjusts the bonding conditions stored in the storage unit  13 . That is, the bonding time corresponding to the predetermined ball collapse amount is adjusted so as to fall within the predetermined numerical range. 
     On the other hand, if the bonding time corresponding to the predetermined ball collapse amount calculated by the calculation unit  25  is determined to be within the predetermined numerical range, the bonding conditions stored in the storage unit  13  are not adjusted. 
     Next, a method for manufacturing a semiconductor device according to the present embodiment will be described. 
     First, the same steps S 1  to S 4  as the above embodiment are performed. 
     Subsequently, bonding is performed based on the bonding conditions stored in the storage unit  13  (step S 5 ). The first control unit  191  of the drive control unit  19  drives and controls the motor  181 Z that controls the position on the Z axis of the capillary  11  based on the load stored in the storage unit  13  so as to apply a load to the ball  12 . The second control unit  192  drives the ultrasonic vibrator  182  based on the vibration conditions of the ultrasonic vibrator stored in the storage unit  13  so as to apply an ultrasonic wave vibration to the ball  12 . 
     During the bonding, the second adjustment unit  30  adjusts the bonding time stored in the storage unit  13  so that the bonding is continued until the position of the capillary  11  reaches a predetermined position. That is, the second adjustment unit  30  adjusts the bonding time stored in the storage unit  13  so that the difference between the first position and the second position reaches a predetermined value. 
     For example, it will be assumed that the storage unit  13  stores a bonding time t 2  in addition to predetermined application conditions for the load and ultrasonic power, and the like. In this case, it will be assumed that the ball thickness exhibits a change as shown by curve C in  FIG. 5 . However, even when the bonding is performed in accordance with the bonding time t 2  in addition to the predetermined conditions for the load and the ultrasonic power, and the like, only the thickness of the ball  12  is changed by a small amount as shown by curve D in  FIG. 5 . In this case, the second adjustment unit  30  adjusts the bonding time so as to be extended (so that the bonding time becomes t 2 +Δt) until the difference between the first position and the second position reaches a predetermined value x 3 . 
     In this way, the ball  12  is bonded to the semiconductor element S. 
     The calculation unit  25  calculates the collapse amount of the ball  12  from the position of the capillary  11  detected by the detection unit  14 . Specifically, the calculation unit  25  calculates the ball collapse amount from the Z-axis position (first position) of the capillary  11  when the capillary  11  is lowered towards the semiconductor element S side so that the ball  12  comes into contact with the pad P of the semiconductor element S (the bonding start time) and the Z-axis position (second position) of the capillary  11  when the ball  12  is bonded by applying a load and an ultrasonic wave vibration thereto (the bonding end time). Here, the bonding end time means the time at which the amount of fluctuation in the Z-axis direction of the capillary  11  is equal to or smaller than a predetermined value and is in a stable state. 
     The timer unit  20  measures the time elapsed until the ball  12  is bonded by applying a load and an ultrasonic wave vibration thereto after the capillary  11  is lowered towards the semiconductor element S side so that the ball  12  formed at the tip end of the capillary  11  comes into contact with the pad P of the semiconductor element S. The calculation unit  25  calculates a bonding time corresponding to a predetermined collapse amount of the ball  12 , in this example, the bonding time corresponding to the difference between the first position and the second position, based on the results of the measurement by the timer unit  20 . 
     Subsequently, the first adjustment unit  26  acquires the results of the calculation by the calculation unit  25  and determines whether or not the bonding time corresponding to a predetermined ball collapse amount calculated by the calculation unit  25  is within a predetermined numerical range. 
     Moreover, if the bonding time corresponding to the predetermined collapse amount of the ball  12  calculated by the calculation unit  25  is determined to be outside the predetermined numerical range, the first adjustment unit  26  adjusts the bonding conditions stored in the storage unit  13 . That is, the bonding time corresponding to the predetermined collapse amount of the ball  12  is adjusted so as to fall within the predetermined numerical range. For example, as shown in  FIG. 5 , when bonding is started by the bonding apparatus  2 , as shown by curve C, the collapse speed of the ball  12  is high. However, when the bonding is repeated, the collapse speed of the ball  12  may decrease, and the bonding time corresponding to a predetermined ball collapse amount may be outside a predetermined numerical range (see curve E). 
     In this case, the first adjustment unit  26  may increase the ultrasonic power among the bonding conditions stored in the storage unit  13  so that the bonding time corresponding to the predetermined ball collapse amount falls within the predetermined numerical range. Regarding the amount of increase in the ultrasonic power, the first adjustment unit  26  may grasp the amount of deviation of the bonding time corresponding to the predetermined ball collapse amount from the predetermined numerical range and set the amount of increase in the ultrasonic power in accordance with the amount of deviation. Specifically, the amount of deviation (not shown) of the bonding time corresponding to the predetermined ball collapse amount from the predetermined numerical range and the amount of increase in the ultrasonic power may be stored in the storage unit  13 , and the first adjustment unit  26  may increase the ultrasonic power based on the data stored in the storage unit  13 . 
     A load may be increased without being limited to the ultrasonic power. In this case, the first adjustment unit  26  may grasp the amount of deviation of the bonding time corresponding to a predetermined collapse amount of the ball  12  from the predetermined numerical range and increase the load in accordance with the amount of deviation. 
     Both the ultrasonic power and the load may be adjusted. 
     If the collapse speed of the ball  12  is too high, the first adjustment unit  26  may grasp the amount of deviation of the bonding time corresponding to the predetermined collapse amount of the ball  12  from the predetermined numerical range and adjust the bonding conditions in accordance with the amount of deviation. 
     On the other hand, if the bonding time corresponding to the predetermined collapse amount of the ball  12  calculated by the calculation unit  25  is determined to be within the predetermined numerical range, the bonding conditions stored in the storage unit  13  are not adjusted. 
     By the above-described steps, the bonding of the pad P of the semiconductor element S and the wire W (the ball  12 ) is completed. Subsequently, the lead (not shown) on the substrate M on which the semiconductor element S is formed is bonded to the wire W held by the capillary  11 . It should be noted that the functions of the present invention are also effective for performing bonding of the lead (not shown) on the substrate M. 
     According to the present embodiment described above, it is possible to obtain the same operational effects as the first embodiment, and the following advantages can be provided. 
     In the present embodiment, the second adjustment unit  30  adjusts the bonding time stored in the storage unit  13  so that the bonding time is extended until the difference between the first position and the second position reaches a predetermined value x 3 . 
     In this way, it is possible to ensure a constant collapse amount in all of the balls  12 . 
     Third Embodiment 
     A third embodiment of the present invention will be described with reference to  FIG. 6 . 
     A bonding apparatus  3  of the present embodiment includes a second storage unit  33  in addition to the constituent elements of the bonding apparatus  1  of the first embodiment. 
     In the bonding apparatus  3 , similarly to the first embodiment, the first adjustment unit  16  adjusts the adjusted bonding conditions (ultrasonic wave application power and load). In this case, however, the first adjustment unit  16  stores the relationship between the adjusted bonding conditions (ultrasonic wave application power and load) and the bonding count in the second storage unit  33 . 
     For example, when the ultrasonic wave power is adjusted by the first adjustment unit  16 , the bonding count and a change in the ultrasonic power are also stored (see  FIG. 7 ). 
     First, a series of operations in the steps S 1  to S 10  of the first embodiment are performed several times, and the relationship between the bonding count and a change in the bonding conditions is stored in the second storage unit  33 . 
     Subsequently, bonding is performed again after replacing the capillary  11 , for example. In this case, bonding of the semiconductor element S and the wire W is performed based on the relationship between the bonding count and the change in the bonding conditions stored in the second storage unit  33 . 
     For example, when the relationship between the bonding count and the change in the ultrasonic power as shown in  FIG. 7  is stored in the second storage unit  33 , bonding of the semiconductor element S and the wire W is performed by adjusting the ultrasonic power in accordance with the relationship shown in  FIG. 7 . 
     According to the present embodiment described above, it is possible to obtain the same operational effects as the first embodiment, and the following advantages can be provided. 
     The relationship between the bonding execution count and a change in the bonding conditions is stored in the second storage unit  33 , and the bonding conditions are changed based on the stored relationship, whereby a desired ball collapse profile can be obtained. 
     The present invention is not limited to the embodiments described above, and modifications, improvements, and the like within a range where the object of the present invention can be achieved are also included in the present invention. 
     In the first embodiment, although the ball collapse amount for a predetermined period was calculated, the present invention is not limited to this, and the time corresponding to a predetermined collapse amount of the ball  12  may be calculated. 
     It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention.