JP4482598B2 - BONDING DEVICE, BONDING DEVICE CORRECTION AMOUNT CALCULATION METHOD, AND BONDING METHOD - Google Patents

Description

  The present invention relates to a bonding apparatus that picks up a semiconductor die attached to a protective sheet and bonds it to a bonding target, a correction amount calculation method for the bonding apparatus, and a bonding method.

  In manufacturing a semiconductor device, a bonding apparatus that joins a semiconductor die onto a lead frame, a substrate, or the like is used. This bonding apparatus is provided with a bonding head having a collet for adsorbing a semiconductor die attached to the tip. Then, the bonding apparatus moves the bonding head to pick up the semiconductor die attached to the protective sheet at the pickup position, and then to the semiconductor die at a predetermined position such as a lead frame or a substrate conveyed at the bonding position. Are bonded (for example, Patent Document 1).

When such a bonding apparatus is operated, the bonding head is thermally deformed by heat generated by a driving unit such as a motor for driving the bonding head. When the bonding apparatus is stopped, the bonding head is cooled and tries to recover. In addition, the displacement amount of deformation and restoration in the bonding head differs between the pickup position and the bonding position. Therefore, in the conventional bonding apparatus, the correction amount at the pickup position and the bonding position corresponding to the operation time and stop time measured in advance is stored in a table, and the correction amount stored in this table is referred to. However, the pickup position and the bonding position are corrected in accordance with the operation time and stop time of the bonding apparatus.
JP-A-11-150162

  By the way, in recent years, the manufacturing process of a semiconductor device has been made in-line, a plurality of bonding apparatuses are arranged in series, and a plurality of wire bonding apparatuses are arranged in series on a die bonding apparatus. As a result, when a failure occurs in another die bonding device or another wire bonding device, the bonding device in which the failure has not occurred is stopped, and therefore a situation where operation and stop frequently occur occurs. It has become like this. However, in the conventional die bonding apparatus, correction is performed based on a correction amount measured in advance. Therefore, if the operation and the stop are repeated frequently, the error increases, and the correction of the pickup position and the bonding position is performed with high accuracy. It has become difficult to do.

  Therefore, an object of the present invention is to provide a bonding apparatus, a correction amount calculation method for the bonding apparatus, and a bonding method that can correct the pickup position and the bonding position with high accuracy.

A bonding apparatus according to the present invention picks up a semiconductor die attached to a protective sheet at a predetermined pickup position by a bonding head provided with a positioning mark and the bonding head, and at the predetermined bonding position the semiconductor die. A bonding control unit that bonds the bonding head to the bonding target, an imaging device that captures the mark when the bonding head is at one of the pickup position and the bonding position, and the bonding head based on the mark image captured by the imaging device . a first correction quantity calculating means for calculating a first correction amount for correcting one of the pickup position and the bonding position, the second correction amount for correcting the other one of the pick-up position and the bonding position of the bonding head the First correction amount calculated by the first correction amount calculating means, and has a second correction amount calculating means for calculating, based on the correlation between the first correction amount and the second correction amount.

In the bonding apparatus according to the present invention, when the bonding head is moved to either the pickup position or the bonding position by the bonding control unit, the imaging apparatus images the mark provided on the bonding head. Then, the first correction amount calculating means calculates a first correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position based on the captured mark image, and further, the second correction amount is calculated. Based on the calculated first correction amount and the correlation between the first correction amount and the second correction amount, the amount calculating means corrects the position of the bonding head at either the pickup position or the bonding position. A second correction amount is calculated. As described above, according to the bonding apparatus according to the present invention, the first correction amount can be calculated by actual measurement by the imaging apparatus. For example, even if the bonding apparatus frequently repeats operation and stop, an error can be obtained. Without increasing, the position of the bonding head at either the pickup position or the bonding position can be corrected with high accuracy. On the other hand, since the second correction amount can be calculated based on the first correction amount calculated by actual measurement and the correlation between the first correction amount and the second correction amount , for example, the bonding apparatus is operated and stopped. Even if it is frequently repeated, the position of the bonding head at either the pickup position or the bonding position can be corrected within the predetermined error range within the predetermined range without increasing the error. In particular, the variation of the displacement amount of the bonding head until the temperature of the bonding head is steady state stability is increased, by performing actual measurement by the imaging device, in the meantime also the pickup position and the bonding position with high precision The position of the bonding head can be corrected. In addition, since it is not necessary to separately provide an imaging device for calculating the second correction amount, an increase in cost can be suppressed.

  In this case, it is preferable that one of the pickup position and the bonding position is a pickup position, and the other of the pickup position and the bonding position is a bonding position. In this bonding apparatus, a mark provided on the bonding head is imaged when the bonding head is at the pickup position. Then, a correction amount for the pickup position is calculated based on the captured mark image, and further, a correction amount for the bonding position is calculated based on the calculated correction amount for the pickup position. Thus, since the position correction by actual measurement is performed at the pickup position of the pickup, which is a pre-bonding process, the pickup position can be corrected with high accuracy even immediately after the bonding apparatus is operated.

  The second correction amount calculating means preferably calculates the second correction amount by adding a predetermined constant to the first correction amount. According to this bonding apparatus, since the second correction amount is calculated by adding a predetermined constant to the first correction amount, the second correction amount can be easily calculated. For this reason, the correlation between the first correction amount and the second correction amount can be adjusted only by changing the constant.

In the bonding apparatus correction amount calculation method according to the present invention, a bonding head provided with a positioning mark picks up a semiconductor die attached to a protective sheet, and bonds the semiconductor die to a bonding target. An imaging step for imaging the mark when in one of the bonding positions, and a first correction for correcting the position of the bonding head at either the pickup position or the bonding position based on the mark image captured in the imaging step. A first correction amount calculation step for calculating one correction amount, and a second correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position are calculated by the first correction amount calculation step . Correction amount and correlation between first correction amount and second correction amount Having a second correction amount calculating step of calculating, based on the.

In the correction amount calculation method of the bonding apparatus according to the present invention, when the bonding head is moved to either the pickup position or the bonding position, the mark provided on the bonding head is imaged in the imaging step. Then, in the first correction amount calculation step, a first correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position is calculated based on the captured mark image, and further, the second correction amount is calculated. In the amount calculating step, the position of the bonding head at either the pickup position or the bonding position is corrected based on the calculated first correction amount and the correlation between the first correction amount and the second correction amount. A second correction amount is calculated. Thus, according to the correction amount calculation method of the bonding apparatus according to the present invention, the first correction amount can be calculated by actual measurement in the imaging step. For example, the bonding apparatus frequently starts and stops repeatedly. However, the position of the bonding head at one of the pickup position and the bonding position can always be corrected with high accuracy without increasing the error. On the other hand, since the second correction amount can be calculated based on the first correction amount calculated by actual measurement and the correlation between the first correction amount and the second correction amount , for example, the bonding apparatus is operated and stopped. Even if the process is repeated frequently, the position of the bonding head at either the pickup position or the bonding position can be corrected with high accuracy within a predetermined range without increasing the error. In particular, the fluctuation of the displacement of the bonding head increases for a while after the start of operation. However, the actual position of the bonding head at the pick-up position and bonding position can be measured with high accuracy by performing an actual measurement during the imaging step. Can be corrected. Furthermore, since it is not necessary to separately provide an imaging device for calculating the second correction amount, an increase in cost can be suppressed.

A correction amount calculation method for a bonding apparatus according to the present invention includes a bonding head provided with a positioning mark, an image pickup apparatus for picking up an image of the mark, and a semiconductor attached to a protective sheet at a predetermined pickup position by the bonding head. Pickup position at which the bonding head picks up the semiconductor die attached to the protective sheet using a bonding apparatus that picks up the die and bonds the semiconductor die to the bonding target at a predetermined bonding position. And an imaging step for imaging a mark when the semiconductor die is at a bonding position for bonding a semiconductor die to a bonding target, and a pickup position and a bonder based on the mark image captured in the imaging step. The corrected with the first correction amount calculating step of calculating a first correction amount for correcting the position of the bonding head in any one of the grayed position, the position of the bonding head in the other of the pickup position and the bonding position 2 A first correction amount calculated in the first correction amount calculation step, and a second correction amount calculation step that calculates the correction amount based on a correlation between the first correction amount and the second correction amount .

In the correction amount calculation method of the bonding apparatus according to the present invention, when the bonding head is moved to either the pickup position or the bonding position by the bonding controller, the mark provided on the bonding head is imaged in the imaging step. . Then, in the first correction amount calculation step, a first correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position is calculated based on the captured mark image, and further, the second correction amount is calculated. In the amount calculating step, the position of the bonding head at either the pickup position or the bonding position is corrected based on the calculated first correction amount and the correlation between the first correction amount and the second correction amount. A second correction amount is calculated. Thus, according to the correction amount calculation method of the bonding apparatus according to the present invention, the first correction amount can be calculated by actual measurement in the imaging step. For example, the bonding apparatus frequently starts and stops repeatedly. However , the position of the bonding head at one of the pickup position and the bonding position can be corrected with high accuracy without increasing the error. On the other hand, since the second correction amount can be calculated based on the first correction amount calculated by actual measurement and the correlation between the first correction amount and the second correction amount , for example, the bonding apparatus is operated and stopped. Even if it is frequently repeated, the position of the bonding head at either the pickup position or the bonding position can be corrected within the predetermined error range within the predetermined range without increasing the error. In particular, the variation of the displacement amount of the bonding head until the temperature of the bonding head is steady state stability is increased, by performing actual measurement by the imaging step, during this period also, the pickup position and the bonding position with high precision The position of the bonding head can be corrected. In addition, since it is not necessary to separately provide an imaging device for calculating the second correction amount, an increase in cost can be suppressed.
In this case, it is preferable that one of the pickup position and the bonding position is a pickup position, and the other of the pickup position and the bonding position is a bonding position. In this bonding method, the mark provided on the bonding head is imaged when the bonding head is at the pickup position. Then, based on the captured mark image, a correction amount of the bonding head position at the pickup position is calculated. Further, based on the calculated correction amount of the bonding head position at the pickup position , the bonding position at the bonding position is calculated . A correction amount of the position of the bonding head is calculated. As described above, since the position correction by actual measurement is performed at the pickup position of the pickup, which is a pre-bonding process, the position of the bonding head at the pickup position is corrected with high accuracy even immediately after the bonding apparatus is operated. be able to.

The bonding method according to the present invention also includes a bonding head provided with a positioning mark, an imaging device for imaging the mark, and a semiconductor die attached to a protective sheet at a predetermined pickup position by the bonding head. Using a bonding apparatus including a bonding control unit for bonding a semiconductor die to a bonding target at a predetermined bonding position, and a pickup position at which the bonding head picks up the semiconductor die attached to the protective sheet, and Based on the imaging step for imaging the mark and the mark image captured in the imaging step when the semiconductor die is at any one of the bonding positions for bonding the semiconductor die to the bonding target, the pickup position and the bonding position It calculates a first correction amount for correcting the position of the bonding head of Re or the other in a first correction step of correcting the first correction amount the position of the bonding head of either one of the pick-up position and the bonding position, The second correction amount for correcting the position of the bonding head at the other one of the pickup position and the bonding position is the first correction amount calculated by the first correction step, and the first correction amount and the second correction amount. A second correction step for calculating based on the correlation and correcting the position of the bonding head at the other of the pickup position and the bonding position with the second correction amount, and any one of the first correction step and the second correction step A die pick-up step for picking up the semiconductor die at the position corrected by one of the steps; Having a transfer step of transferring the semiconductor die picked up the corrected position by the other of the steps and the second correction step, and a bonding step of bonding a semiconductor die has been transferred from the transfer step to the bonding target.

In the bonding method according to the present invention, when the bonding head is moved to either the pickup position or the bonding position by the bonding control unit, the mark provided on the bonding head is imaged in the imaging step. Then, in the first correction step, the position of the bonding head at one of the pickup position and the bonding position is corrected by the first correction amount calculated based on the captured mark image, and further in the second correction step. The position of the bonding head at either the pickup position or the bonding position with the calculated first correction amount and the second correction amount calculated based on the correlation between the first correction amount and the second correction amount. Correct. In the die pick-up step, the semiconductor die is picked up at the pick-up position of the bonding head corrected in the first correction step, and in the bonding step, the semiconductor die is bonded at the bonding position of the bonding head corrected in the second correction step. . As described above, according to the bonding method according to the present invention, the first correction amount can be calculated by actual measurement in the imaging step. Therefore, for example, even if the bonding apparatus repeatedly operates and stops, an error is generated. Without increasing, the position of the bonding head at either the pickup position or the bonding position can be corrected with high accuracy. On the other hand, since the second correction amount can be calculated based on the first correction amount calculated by actual measurement and the correlation between the first correction amount and the second correction amount , for example, the bonding apparatus is operated and stopped. Even if it is frequently repeated, the position of the bonding head at either the pickup position or the bonding position can be corrected within the predetermined error range within the predetermined range without increasing the error. In particular, the variation of the displacement amount of the bonding head until the temperature of the bonding head is steady state stability is increased, by performing actual measurement by the imaging step, during this period also, the pickup position and the bonding position with high precision The position of the bonding head can be corrected. Thereby, the semiconductor die can be picked up with high accuracy, and the picked-up semiconductor die can be bonded with high accuracy. In addition, since it is not necessary to separately provide an imaging device for calculating the second correction amount, an increase in cost can be suppressed.

  In these cases, it is preferable that one of the pickup position and the bonding position is a pickup position, and the other of the pickup position and the bonding position is a bonding position. In this bonding method, the mark provided on the bonding head is imaged when the bonding head is at the pickup position. Then, a correction amount for the pickup position is calculated based on the captured mark image, and further, a correction amount for the bonding position is calculated based on the calculated correction amount for the pickup position. Thus, since the position correction by actual measurement is performed at the pickup position of the pickup, which is a pre-bonding process, the pickup position can be corrected with high accuracy even immediately after the bonding apparatus is operated.

  According to the present invention, the pickup position and bonding position can be corrected with high accuracy.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a bonding apparatus, a correction amount calculation method for a bonding apparatus, and a bonding method according to the present invention will be described in detail with reference to the drawings. In all drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a diagram illustrating a bonding apparatus according to an embodiment. As shown in FIG. 1, the bonding apparatus 1 of this embodiment picks up a diced semiconductor die 2 from a semiconductor wafer 3 and bonds it to a predetermined position of a lead frame 4. For this reason, the bonding apparatus 1 includes a transport device 5 that transports the lead frame 4, a wafer holder 6 that holds the semiconductor wafer 3, and a head unit 7 that picks up the semiconductor die 2 and performs bonding.

  Here, the configuration of the lead frame 4 transported by the transport device 5 will be described. FIG. 2 is a top view of the lead frame. The lead frame 4 shown in FIG. 2 is a 3-pin structure lead frame. The lead frame 4 is provided with an island 10 to which the semiconductor die 2 is bonded, and a pair of leads 11 that are separated from the island 10 and are disposed on both sides of the island 10 in the X direction. The island 10 is coated with a silver paste for bonding the semiconductor die 2. In the present embodiment, the semiconductor die 2 is joined by silver paste, but the semiconductor die 2 may be joined to the island 10 by thermocompression bonding using thermal eutectic.

  As shown in FIG. 1, the transport device 5 transports the lead frame 4 while guiding it in the X direction. A bonding stage 12 is attached to the transport device 5 to hold the surface of the lead frame 4 being transported by a wind clamper (not shown). Inside the bonding stage 12, a heater 13 for heating the lead frame 4 being conveyed is attached in order to facilitate the bonding of the semiconductor die 2 to the lead frame 4. The wind clamper is partially opened to bond the semiconductor die 2 to the lead frame 4.

  The wafer holder 6 holds the semiconductor wafer 3 in a state where it is attached to a protective sheet 14 that is a dicing tape. The semiconductor wafer 3 is diced in a state of being attached to the protective sheet 14, and is constituted by a plurality of semiconductor dies 2. The wafer holder 6 is installed on an XY table (not shown) that is movable in the X direction and the Y direction, and is disposed adjacent to the transfer device 5.

  The head unit 7 picks up a predetermined semiconductor die 2 from the semiconductor wafer 3 held by the wafer holder 6 and bonds the picked-up semiconductor die 2 to the island 10 of the lead frame 4 transferred to the transfer device 5. . The head unit 7 includes a base 18 in which a first slide surface 16 and a second slide surface 17 are configured in two stages.

  The first slide surface 16 of the base 18 is provided with a bonding head 21 that can be moved in the X direction and the Y direction on the first slide surface 16 by an X-axis motor 19 and a Y-axis motor 20. A slide arm 23 that is movable in the Z direction by a Z-axis motor 22 is attached to the tip of the bonding head 21, and a collet 24 that adsorbs the semiconductor die 2 is detachably attached to the tip of the slide arm 23. It has been. The collet 24 has a suction hole formed at the tip thereof for adsorbing the semiconductor die 2. In FIG. 1, the collet 24 is formed in a truncated cone shape with a thin tip so that the fine semiconductor die 2 can be adsorbed.

  A target 25 for confirming the position of the collet 24 is attached to the tip of the slide arm 23. The target 25 is formed in a plate shape facing substantially in the Z direction, and a cross-shaped mark 26 is engraved on the upper surface.

  A camera unit 28 that can be moved in the Y direction on the second slide surface 17 by the camera Y-axis motor 27 is installed on the second slide surface 17 of the base 18. The camera unit 28 extends along the second slide surface 17 in the direction of the transfer device 5 and the wafer holder 6. The camera unit 28 is attached with a bonding position imaging camera 29 that images the bonding position, a pickup position imaging camera 30 that images the pickup position, and a mark imaging camera 31 that images the mark 26 of the target 25. .

  The bonding position imaging camera 29 is arranged so that the central axis of the optical system is perpendicular to the surface of the lead frame 4 conveyed by the conveying device 5. Then, the bonding position imaging camera 29 images the island 10 for bonding the semiconductor die 2 in the lead frame 4 conveyed by the conveying device 5.

  The pickup position imaging camera 30 is disposed on the tip side of the bonding position imaging camera 29. The pickup position imaging camera 30 is arranged so that the central axis of the optical system is perpendicular to the surface of the semiconductor wafer 3 held by the wafer holder 6. The pickup position imaging camera 30 images the semiconductor die 2 to be picked up from the semiconductor wafer 3 held by the wafer holder 6.

  FIG. 3 is a diagram for explaining the arrangement of the mark imaging camera. As shown in FIG. 3, the mark imaging camera 31 is arranged apart from the pickup position imaging camera 30 in the X direction. Further, the mark imaging camera 31 is arranged so as to be inclined so that the central axis of the optical system passes through the center of the mark 26 of the target 25 (intersection of crosshairs). That is, the mark imaging camera 31 is inclined with respect to the central axis of the optical system of the pickup position imaging camera 30, that is, the axis perpendicular to the surface of the semiconductor die 2. The mark imaging camera 31 images the mark 26 of the target 25 when the slide arm 23 of the bonding head 21 is at the pickup position.

  As shown in FIG. 1, the bonding apparatus 1 is provided with a control unit 40 that controls the transfer device 5, the wafer holder 6, the head unit 7, and the like. The control unit 40 is configured by a computer having a CPU 50 and a memory 51 in which control data and the like are stored as main components. The control unit 40 then transmits the drive control signal to the camera Y-axis motor 27, the bonding position imaging camera 29, the pickup position imaging camera 30, and the mark imaging camera 31. Y that transmits an imaging control signal and transmits a drive control signal to the Y-axis motor 20 and a camera interface 53 that acquires an image captured by the bonding position imaging camera 29, the pickup position imaging camera 30, and the mark imaging camera 31. An axis motor interface 54, an X axis motor interface 55 that transmits a drive control signal to the X axis motor 19, a Z axis motor interface 56 that transmits a drive control signal to the Z axis motor 22, and the transport device 5. On the other hand, a transport control signal for transporting the lead frame 4 is sent. A conveying device interface 57 for signal to, and a heater interface 58 for transmitting a heating control signal to the heater 13.

  FIG. 4 is a functional block diagram illustrating the functional configuration of the control unit. As shown in FIG. 4, the control unit 40 functionally includes a drive control unit 42, an imaging control unit 41, and a correction amount calculation unit 43.

  The imaging control unit 41 controls the driving of the camera Y-axis motor 27 and controls the bonding position imaging camera 29, the pickup position imaging camera 30, and the mark imaging camera 31. That is, the imaging control unit 41 causes the bonding position imaging camera 29 to image the island 10 of the lead frame 4 to be bonded, and causes the pickup position imaging camera 30 to image the semiconductor die 2 to be picked up on the semiconductor wafer 3. . Further, the imaging control unit 41 causes the mark imaging camera 31 to image the mark 26 of the target 25 when the bonding head 21 is at the pickup position, and acquires the captured mark image.

  The drive control unit 42 performs drive control of the X-axis motor 19, Y-axis motor 20, and Z-axis motor 22, and performs suction control of the collet 24. Thus, the bonding head 21 is moved to the pickup position to pick up the semiconductor die 2, and then the bonding head 21 is moved to the bonding position to bond the semiconductor die 2 to the lead frame 4.

  The correction amount calculation unit 43 includes a deviation amount (pickup position correction amount) of the collet 24 (slide arm 23) when the bonding head 21 is at the pickup position, and a collet 24 (slide arm) when the bonding head 21 is at the bonding position. 23) and a deviation amount (bonding position correction amount) are calculated.

The amount of deviation of the collet 24 at the pickup position is calculated based on the mark image captured by the mark imaging camera 31. That is, the correction amount calculation unit 43 registers a mark image captured at an arbitrary timing as a reference position. Then, the amount of deviation of the collet 24 at the pickup position can be calculated by comparing the reference position with the captured mark image and calculating the amount of deviation of the center of the mark 26. The shift amount is calculated by dividing into a shift amount Δx ₁ in the X direction and a shift amount Δy _{1 in the} Y direction. Then, the correction amount calculation unit 43 sets the calculated shift amount as the pickup position correction amount. The calculated pickup position correction amount is a correction amount when the drive control unit 42 controls driving of the bonding head 21.

On the other hand, the amount of deviation of the collet 24 at the bonding position (bonding position correction amount) is calculated by adding a predetermined constant to the amount of deviation of the collet at the pickup position (pickup position correction amount). FIG. 5 is a diagram showing an example of a deviation amount between the bonding position and the pickup position in the X direction of the collet 24 with the passage of time, and FIG. 5A shows the deviation amount of the bonding position. FIG. 5B shows the amount of deviation at the pickup position. FIG. 6 is a diagram illustrating an example of a deviation amount between the bonding position and the pickup position in the Y direction of the collet 24 over time, and FIG. 6A illustrates the deviation amount of the bonding position. FIG. 6B shows a deviation amount at the pickup position. 5 and 6, the time t indicates the time from when the bonding apparatus is operated until the head unit 7 is in a steady state where the temperature is stable. As shown in FIGS. 5 and 6, a predetermined correlation is established between the amount of deviation of the collet 24 at the bonding position and the amount of deviation of the collet 24 at the pickup position. For example, assuming that the displacement amount at the bonding position is (Δx ₁ , Δy ₁ ) and the displacement amount at the pickup position is (Δx ₂ , Δy ₂ ), Δx ₂ = α · Δx ₁ (1) and Δy ₂ = β · Δx ₂ (2) is established. 5 and 6, 0.5 is applied to the constant α, and 0.8 is applied to the constant β. Therefore, the correction amount calculation unit 43 calculates the bonding position correction amount by adding the constant α and the constant β to the pickup position correction amount using the above formulas (1) and (2). The calculated bonding position correction amount is a correction amount when the drive control unit 42 controls driving of the bonding head 21.

  Next, the operation of the bonding apparatus 1 according to the present embodiment will be described with reference to FIGS. FIG. 7 is a flowchart showing the reference position registration process, and FIG. 8 is a flowchart showing the bonding process. The processing operation of the bonding apparatus 1 described below is performed under the control of the control unit 40.

  First, reference position registration processing will be described with reference to FIG. The reference position registration process is performed at an arbitrary timing, for example, when the collet 24 is replaced or when the bonding apparatus 1 is started.

  As shown in FIG. 7, in the reference position registration process, first, the bonding head 21 is moved to the pickup position (step S1). That is, in step S1, drive control of the X-axis motor 19 and the Y-axis motor 20 is performed, and the bonding head 21 is moved so that the collet 24 is positioned on the vertical axis passing through the center of the semiconductor die 2 to be picked up.

  Next, a mark image is captured (step S2). That is, in step S2, imaging control of the mark imaging camera 31 is performed, the mark 26 of the target 25 attached to the slide arm 23 is imaged, and a mark image which is this captured image is acquired.

  Next, the mark image is registered as a reference position (step S3). That is, in step S3, the mark image acquired in step S2 is binarized, and the center of the cross line of the mark 26 is obtained. Then, the coordinates of the center are registered as a reference position.

  When the reference position is registered in this way, the reference position registration process ends.

  Next, the bonding process will be described with reference to FIG.

  As shown in FIG. 8, in the bonding process, first, the bonding stage 12 is heated by the heater 13 (step S11). That is, in step S11, for example, the bonding stage 12 is heated to 400 ° C.

  Next, the lead frame 4 is conveyed in the X direction, and the island 10 to be bonded is detected (step S12). That is, in step S <b> 12, first, the drive control unit 42 performs drive control of the camera Y-axis motor 27 to move the bonding position imaging camera 29 onto the conveyance path of the lead frame 4. Then, the imaging control unit 41 controls the driving of the transport device 5 and transports the lead frame 4 until the island 10 of the lead frame 4 reaches the center position of the field of view of the bonding position imaging camera 29. FIG. 9 is a view showing the field of view of the bonding position imaging camera. In FIG. 9, a cross line 61 indicates the center of the field of view of the bonding position imaging camera 29. Then, as shown in FIG. 9, when the center of the island 10 matches the center of the cross line 61, the conveyance of the lead frame 4 is stopped.

  Next, the semiconductor die 2 to be picked up is detected from the semiconductor wafer 3 held by the wafer holder 6 (step S13). That is, in step S 13, first, drive control of the camera Y-axis motor 27 is performed, and the pickup position imaging camera 30 is moved to the pickup position on the semiconductor wafer 3 held by the wafer holder 6. Then, imaging control of the pickup position imaging camera 30 is performed, and each semiconductor die 2 of the semiconductor wafer 3 is imaged. Then, the wafer holder 6 is moved in the X direction and the Y direction so that the semiconductor die 2 to be picked up becomes the center position of the visual field of the pick-up position imaging camera 30. FIG. 10 is a view showing the field of view of the pickup position imaging camera 30. In FIG. 10, a cross line 62 indicates the center of the visual field of the pickup position imaging camera 30. Then, as shown in FIG. 10, the wafer holder 6 is moved so that the center of the semiconductor die 2 to be picked up becomes the center of the cross line 62.

  Next, the collet 24 is moved to the pickup position (step S14). That is, in step S14, drive control of the X-axis motor 19 and the Y-axis motor 20 is performed, and the bonding head 21 is moved so that the collet 24 is positioned on the vertical axis passing through the center of the semiconductor die 2 to be picked up.

  Next, a mark image is captured (step S15). That is, in step S15, imaging control of the mark imaging camera 31 is performed, the mark of the target 25 attached to the slide arm 23 is imaged, and a mark image which is this captured image is acquired.

Next, a pickup position correction amount is calculated based on the captured mark image (step S16). That is, in step S16, first, the mark image acquired in step S15 is binarized, and the center of the cross line of the mark 26 is obtained. Then, a deviation amount between the center coordinates and the registered position registered in step S3 of the reference position registration process described above is calculated. At this time, the calculated shift amount is calculated separately for the X direction and the Y direction, and is set as a shift amount Δx ₁ in the X direction and a shift amount Δy ₁ in the Y direction. Then, the calculated shift amount (Δx ₁ , Δy ₁ ) is set as the pickup position correction amount (Δx ₁ , Δy ₁ ).

  Next, the pickup position of the collet 24 is corrected based on the captured mark image (step S17). That is, in step S17, drive control of the X-axis motor 19 and the Y-axis motor 20 is performed, and the bonding head 21 is moved so that the collet 24 moves by the pickup position correction amount calculated in step S16.

  Next, the semiconductor die 2 is picked up (step S18). That is, in step S 18, first, drive control of the Z-axis motor 22 is performed, the slide arm 23 is lowered, and the collet 24 is brought close to the semiconductor die 2. Then, the semiconductor die 2 is pushed up from the back side of the protective sheet 14, the collet 24 is sucked, the semiconductor die 2 is attracted to the collet 24, and the semiconductor die 2 is peeled from the protective sheet 14. The semiconductor die 2 can be pushed up by, for example, pushing up the needle-like member from the back side of the protective sheet 14 with a pushing mechanism (not shown) or the like. Then, drive control of the Z-axis motor 22 is performed, the slide arm 23 is raised, and the collet 24 is returned to the original position.

Next, a bonding position correction amount is calculated based on the pickup position correction amount (step S19). That is, in step S19, first, the bonding position correction amount is calculated using the above-described equations (1) and (2) for the bonding position correction amount calculated in step S17. At this time, the bonding position correction amount to be calculated is calculated separately for the X direction and the Y direction. When the amount of deviation Δx ₂ in the X direction is assumed to be the amount of deviation Δy ₂ in the Y direction, the bonding position correction amount (Δx ₂ , Δy ₂ ) is the X component and Y of the pickup position correction amount (Δx ₁ , Δy ₁ ). It can be calculated by adding a constant α and a constant β to each component.

Next, the collet 24 is moved to the bonding position (step S20). That is, in step S20, first, the bonding position is corrected with the bonding position correction amount (Δx ₂ , Δy ₂ ) calculated in step S19. Then, drive control of the X-axis motor 19 and the Y-axis motor 20 is performed, and the bonding head 21 is moved so that the collet 24 is at the corrected bonding position.

  Next, the semiconductor die 2 is bonded (step S21). That is, in step S21, first, drive control of the Z-axis motor 22 is performed, the slide arm 23 is lowered, and the semiconductor die 2 adsorbed by the collet 24 is pressed against the island 10. At this time, since the lead frame 4 is heated by the heater 13, the semiconductor die 2 is bonded to the island 10 by pressing the semiconductor die 2 to the island 10. Then, drive control of the Z-axis motor 22 is performed, the slide arm 23 is raised, and the collet 24 is returned to the original position.

  When step S21 is completed, it is determined whether or not the semiconductor die 2 is bonded to all the islands 10 of the lead frame 4 (step S22). And when it determines with the island 10 which has not bonded remaining (step S22: NO), it returns to step S12 and repeats step S12-step S21 again. On the other hand, if it is determined that bonding is performed on all the islands 10 (step S22: YES), the bonding process is terminated.

  Thus, in the bonding apparatus 1 according to the present embodiment, when the collet 24 is moved to the pickup position by the drive control unit 42 of the control unit 40, the mark imaging camera 31 is attached to the target 25 attached to the bonding head 21. The mark 26 is imaged. Then, the correction amount calculation unit 43 of the control unit 40 calculates the pickup position correction amount based on the captured mark image, and the correction amount calculation unit 43 further calculates the pickup position correction amount based on the calculated pickup position correction amount. A bonding position correction amount is calculated. As described above, according to the bonding apparatus 1 according to the present embodiment, the pickup position correction amount can be calculated by actual measurement by the mark imaging camera 31, so even if the bonding apparatus 1 is frequently operated and stopped. The pickup position can be corrected with high accuracy without increasing the error. On the other hand, since the bonding position correction amount can be calculated based on the pickup position correction amount calculated by actual measurement, even if the bonding apparatus 1 is repeatedly operated and stopped frequently, the bonding position correction is not increased without increasing the error. Can be corrected within a predetermined error range. In particular, the fluctuation of the displacement amount of the head unit 7 increases until the temperature of the head unit 7 reaches a steady state where the temperature becomes stable. In addition, the bonding position can be corrected. In addition, since it is not necessary to separately provide a camera for calculating the bonding position correction amount, an increase in cost can be suppressed.

  Further, according to this bonding apparatus 1, since the position correction by actual measurement is performed at the pickup position of the pickup which is a pre-bonding process, the pickup position is corrected with high accuracy even immediately after the bonding apparatus 1 is operated. can do.

  Further, according to the bonding apparatus 1, the correction amount calculation unit 43 calculates the bonding position correction amount by adding a predetermined constant to the pickup position correction amount, so that the bonding position correction amount can be easily calculated. . For this reason, the correlation between the pickup position correction amount and the bonding position correction amount can be adjusted only by changing the constant.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the calculation of the bonding position correction amount has been described as a predetermined constant added to the pickup position correction amount. However, a correlation is established between the bonding position correction amount and the pickup position correction amount. Any arithmetic expression may be used. For example, the calculation may be performed by using a function F (t) having an elapsed time t from the start of driving of the bonding apparatus 1 as a variable.

  In the above embodiment, the pickup position correction amount is calculated based on the mark image captured by the mark imaging camera 31, and the bonding position correction amount is calculated based on the pickup position correction amount. The position correction amount may be calculated based on the mark image captured by the mark imaging camera 31, and the pickup position correction amount may be calculated based on the bonding position correction amount. In this case, the imaging control unit 41 of the control unit 40 calculates the bonding position correction amount based on the mark image by causing the mark imaging camera 31 to image the mark 26 when the collet 24 reaches the bonding position. Can do.

  In the above embodiment, the mark image is picked up when the bonding head 21 is moved so that the collet 24 is at the pickup position. However, the slide arm 23 is further lowered to collet. 24 may be performed in the state of being close to the semiconductor die 2.

It is the figure which showed the bonding apparatus which concerns on embodiment. It is a top view of a lead frame. It is a figure for demonstrating arrangement | positioning of a mark imaging camera. It is a functional block diagram which illustrates the functional composition of a control part. The amount of misalignment between the bonding position and the pickup position of the collet in the X direction over time is shown, (a) shows the bonding position, and (b) shows the pickup position. The amount of misalignment between the bonding position and the pickup position of the collet in the Y direction as time elapses is shown, (a) shows the bonding position, and (b) shows the pickup position. It is a flowchart which shows the registration process of a reference position. It is a flowchart which shows a bonding process. It is the figure which showed the visual field of the bonding position imaging camera. It is the figure which showed the visual field of the pick-up position imaging camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bonding apparatus, 2 ... Semiconductor die, 3 ... Semiconductor wafer, 4 ... Lead frame, 5 ... Conveyance apparatus, 6 ... Wafer holder, 7 ... Head unit, 10 ... Island, 11 ... Lead, 12 ... Bonding stage, 13 ... Heater , 14 ... Protective sheet, 16 ... First slide surface, 17 ... Second slide surface, 18 ... Base, 19 ... X-axis motor, 20 ... Y-axis motor, 21 ... Bonding head, 22 ... Z-axis motor, 23 ... Slide Arm, 24 ... Collet, 25 ... Target, 26 ... Mark, 27 ... Y-axis motor for camera, 28 ... Camera unit, 29 ... Bonding position imaging camera, 30 ... Pickup position imaging camera, 31 ... Mark imaging camera (imaging device ) , 40 ... control unit (bonding control unit, the first correction amount calculating means, the second correction amount calculating means), 41 ... imaging Control unit, 42 ... drive control unit (bonding control unit), 43 ... correction amount calculating section (first correction amount calculating means, the second correction amount calculating means), 50 ... CPU, 51 ... memory, Y-axis 52 ... camera Motor interface 53... Camera interface 54. Y-axis motor interface 55. X-axis motor interface 56. Z-axis motor interface 57 57 Conveyor interface 58. Heater interface 61.

Claims (8)

A bonding head provided with positioning marks;
A bonding control unit that picks up a semiconductor die attached to the protective sheet at a predetermined pickup position by a bonding head, and bonds the semiconductor die to a bonding target at a predetermined bonding position;
An imaging device for imaging the mark when the bonding head is at either the pickup position or the bonding position;
First correction amount calculating means for calculating a first correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position based on the mark image captured by the imaging device;
The second correction amount for correcting the position of the bonding head at the other of the pickup position and the bonding position includes the first correction amount calculated by the first correction amount calculating means, and the first correction amount and the second correction amount. A second correction amount calculating means for calculating based on the correlation with
A bonding apparatus.   The bonding apparatus according to claim 1, wherein one of the pickup position and the bonding position is a pickup position, and the other of the pickup position and the bonding position is a bonding position.   2. The bonding apparatus according to claim 1, wherein the second correction amount calculating means calculates the second correction amount by adding a predetermined constant to the first correction amount. When the bonding head provided with a positioning mark is at either one of the pickup position for picking up the semiconductor die attached to the protective sheet and the bonding position for bonding the semiconductor die to the bonding target, the mark is An imaging step for imaging;
A first correction amount calculating step for calculating a first correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position based on the mark image captured in the imaging step;
The second correction amount for correcting the position of the bonding head at the other of the pickup position and the bonding position is the first correction amount calculated by the first correction amount calculating step, and the first correction amount and the second correction amount. A second correction amount calculating step for calculating based on the correlation with
A correction amount calculation method for a bonding apparatus. A bonding head provided with a positioning mark, an imaging device for imaging the mark, and the bonding head pick up the semiconductor die attached to the protective sheet at a predetermined pickup position, and the semiconductor die at the predetermined bonding position. Using a bonding apparatus comprising a bonding control unit for bonding a bonding target to a bonding target,
An imaging step for imaging a mark when the bonding head is at either one of a pickup position for picking up a semiconductor die attached to the protective sheet and a bonding position for bonding the semiconductor die to a bonding target;
A first correction amount calculating step for calculating a first correction amount for correcting the position of the bonding head at one of the pickup position and the bonding position based on the mark image captured in the imaging step;
The second correction amount for correcting the position of the bonding head at the other of the pickup position and the bonding position is the first correction amount calculated by the first correction amount calculating step, and the first correction amount and the second correction amount. A second correction amount calculating step for calculating based on the correlation with
A correction amount calculation method for a bonding apparatus.   The correction amount calculation method according to claim 5, wherein one of the pickup position and the bonding position is a pickup position, and the other of the pickup position and the bonding position is a bonding position. A bonding head provided with a positioning mark, an imaging device for imaging the mark, and the bonding head pick up the semiconductor die attached to the protective sheet at a predetermined pickup position, and the semiconductor die at the predetermined bonding position. Using a bonding apparatus comprising a bonding control unit for bonding a bonding target to a bonding target,
An imaging step for imaging a mark when the bonding head is at either one of a pickup position for picking up a semiconductor die attached to the protective sheet and a bonding position for bonding the semiconductor die to a bonding target;
Based on the captured mark image in the imaging step, to calculate the first correction amount for correcting the position of the bonding head in any one of the pick-up position and the bonding position, in either the pick-up position and the bonding position A first correction step for correcting the position of the bonding head with a first correction amount;
The second correction amount for correcting the position of the bonding head at the other one of the pickup position and the bonding position is the first correction amount calculated by the first correction step, and the first correction amount and the second correction amount. A second correction step of calculating based on the correlation and correcting the position of the bonding head at either the pickup position or the bonding position with a second correction amount;
A die pick-up step for picking up a semiconductor die at the pick-up position of the bonding head corrected by one of the first correction step and the second correction step;
A transfer step of transferring the semiconductor die picked up to the bonding position of the bonding head corrected by either one of the first correction step and the second correction step;
A bonding step for bonding the semiconductor die transferred from the transfer step to a bonding target;
A bonding method.   The bonding method according to claim 7, wherein one of the pickup position and the bonding position is a pickup position, and the other of the pickup position and the bonding position is a bonding position.

Images