JP4049721B2 - Bonding method, bonding program, and bonding apparatus - Google Patents

Description

  The present invention relates to a bonding method, a bonding program, and a bonding apparatus, and in particular, a bonding method, a bonding program, and a bonding apparatus for performing bonding by reciprocating a collet portion that holds a chip between a chip supply position and a bonding position. About.

  A bonding apparatus is used to bond the chip to a lead frame or a circuit board. The operation in the bonding apparatus is roughly performed as follows. (1) A collet capable of adsorbing a chip at the tip is used. First, the collet is brought directly above a chip supply unit such as a diced wafer ring (positioning). (2) The collet is lowered directly and the chip is adsorbed from the wafer ring (adsorption). (3) Raise the collet directly above while holding the chip (pickup). (4) The collet holding the chip is transported to a position just above the position where bonding such as a lead frame is performed (transport and positioning). (5) The collet is lowered directly, and the chip is pressed against a gold pad portion such as a lead frame at the bonding position. Here, the bonding portion is heated and bonding is performed by thermocompression bonding (bonding). (6) Raise the collet directly above (bonding is completed). (7) Bring the collet directly above the chip supply unit (conveyance and positioning). By repeating this, a new chip can be bonded sequentially to a new lead frame.

  Here, at the time of bonding, it is necessary to press the chip against the lead frame to be bonded with a certain pressing pressure. This pressing can also be performed by a fixed urging means such as a spring, but the setting of the pressing pressure varies and bonding tends to vary. Therefore, Patent Document 1 discloses that an electronic component is held on a mounting head provided on a stage for conveyance and is pressed against the mounting head using a voice coil motor. In Patent Document 2, the spindle is rotatably supported by a spindle housing that is relatively moved up and down by an elevating device, a rod is provided inside the spindle, a component is held by a suction port at the tip of the rod, and the rod is pressurized by air pressure. It is disclosed.

  In this way, by separating the collet that holds the chip and the transport stage that transports the whole, and by providing the transport stage with a pressurizing device that applies pressing pressure to the collet, the pressing pressure is controlled to stabilize the bonding. be able to.

  Along with the stability of bonding, another important problem of the bonding apparatus is high-speed performance. For example, UPH (Unit Per Hour) is used as a performance index as the number of bonding processes per unit time. As the bonding speed increases, the acceleration of ascending / descending applied to the collet increases, and vibration between the collet and the transport stage during transport may occur, which may hinder speeding up. A pressure device is also used to prevent this vibration. For example, by providing a pressure receiving portion such as a “collar” on the collet and pressing the collet against the transfer stage with a certain pressure by a pressurizing device, the movement between the collet and the transfer stage can be restricted. As described above, in order to increase the speed, it is desirable to transport the collet and the transport stage as a single unit so that the collet is always pressed against the transport stage to suppress excessive vibration. At the bonding position, the same pressure device can be used to control the pressure to the pressing pressure required for bonding.

JP-A-7-106352 JP-A-5-218689

  Conventional bonding work has a further problem in speeding up. That is, in the bonding operation, many steps from (1) to (7) must be repeated as described above, which takes time. Therefore, when analyzing the above-described bonding operation, the bonding position once ascends directly above, then takes the conveyance path to the chip supply position, and also at the chip supply position, the conveyance path to just above the bonding position. After that, it descends directly below. That is, the conveyance between the bonding position and the chip supply position is not a direct type, and there is a movement directly above or below that. Thus, the conveyance between the two positions is not a direct type, which is one of the factors that hinder UPH.

  The circumstances that make it difficult to carry the transfer between the bonding position and the chip supply position to the direct type are as follows.

While performing the bonding at Bo bindings position, the chip supply position is performed positioning of Uefaringu, then collet is adjusted so that the next new tip located just beneath that when came to chip supply position Done. However, not all non-defective chips are always arranged in the wafer ring, and the chip next to the previously picked-up position may be defective. Therefore, the quality of the chip is judged by an identification camera or the like, and if it is a defective chip, the chip is skipped and a good chip is brought to the chip supply position. If time is taken for positioning of the wafer ring by detecting a defective chip in this way, the collet cannot move from the bonding position to the chip supply position.

  At the bonding position, if the chip is kept waiting while the chip is pressed against the lead frame beyond the optimum bonding time, for example, heating during bonding becomes excessive, bonding performance is deteriorated, and collet is damaged. Therefore, it is desirable to lift the collet from the bonding position when the optimum bonding time is exceeded. For this reason, it is conceivable that the transfer stage is once lifted from the bonding position and waits for positioning of the wafer ring. If it does in this way, a conveyance stage cannot go straight from a bonding position to a chip supply position.

  As described above, the conventional bonding method has a limit in increasing the bonding speed. An object of the present invention is to provide a bonding method, a bonding program, and a bonding apparatus capable of solving the problems of the prior art and achieving higher bonding speed.

To achieve the above object, a bonding method according to the present invention, X holds movable collet for sucking holding the tip in the Z direction, a collet table movable in Y, Z3 direction, that attached to the collet table using the collet for closed and a driving source providing a driving force to move the collet to collet table in the Z direction a collet drive source, and a pickup step for picking up the chip by the collet in the chip supply position, the chip supply position From the bonding position to the bonding position , the collet and the collet table are integrated based on the movement trajectory in the X, Y, and Z3 directions. , Collet against collet table by driving source A driving process in which a driving force is applied in a first direction that is moved in the Z direction and pressed toward the bonding target for a predetermined time to bond the chip to the bonding target, and from the bonding position to the chip supply position, in the X, Y, and Z3 directions In a bonding method including a return path transporting process in which the collet and the collet table are integrally transported based on the motion trajectory relating to the movement path, the position of the collet table is left as it is when a predetermined time has passed at the bonding position. And a bonding retracting step of applying a driving force in the second direction opposite to the first direction to the collet by the driving source to move the collet in the Z direction with respect to the collet table to lift and retract from the bonding position. .

The bonding program according to the present invention, there collet for sucking and holding the chip X is movably held in the Z-direction, Y, and Z3 direction movable collet table, with the collet driving source that is attached to the collet table the collet to collet table using the collet for closed and a driving source providing a driving force to move in the Z-direction, the collet portion to the bonding apparatus by reciprocating perform bonding between the chip supply position and the bonding position Te A bonding program to be executed, which includes a pickup processing procedure for picking up a chip by a collet at a chip supply position, and a collet and a collet table from the chip supply position to the bonding position based on movement trajectories in the X, Y, and Z3 directions. As a unit, the collet part is carried directly. In the first direction in which the collet table is moved in the Z direction by the drive source and pushed toward the bonding object while keeping the collet table position at the bonding position at the forward transfer processing procedure to be sent and the bonding position. Based on the bonding process procedure for bonding the chip to the bonding target for a predetermined time and the movement locus in the X, Y, Z3 directions from the bonding position to the chip supply position , the collet and the collet table are integrated into When a predetermined time has elapsed at the bonding position, the collet table position is left as it is, and the drive source applies a driving force in the second direction opposite to the first direction to the collet. Give the collet to the Z direction with respect to the collet table It is characterized in that a bonding evacuation processing procedure for moving and pulling out from the bonding position is executed.

The bonding apparatus according to the present invention is a bonding apparatus that includes a collet unit that holds a chip and a control unit, and performs bonding by reciprocating the collet unit between a chip supply position and a bonding position. includes a collet for sucking and holding the chip, and held movably collet in the Z-direction X, Y, and Z3 direction movable collet table, with respect to the collet table a collet drive source that is attached to the collet table a driving source providing a driving force for moving the collet in the Z direction, and a control section includes a pick-up processing module to pick up the chip by the collet in the chip supply position, to the bonding position from the chip supply position, X, Y Based on the motion trajectory in the Z3 direction, the collet and collet table are As a body, the forward transfer processing module that transports the collet straightly, and at the bonding position, the collet table is left as it is, and the collet is moved in the Z direction by the drive source against the collet table and pressed against the bonding object. A bonding processing module for applying a driving force in a first direction for a predetermined time and bonding a chip to a bonding target ; and a collet and a collet table from a bonding position to a chip supply position based on movement trajectories in the X, Y, and Z3 directions; And a return path transport processing module that transports the collet straightly, and when the predetermined time has elapsed at the bonding position, the collet table is left in the position and the collet is moved in the direction opposite to the first direction by the drive source. Give driving force in the second direction It is characterized by having a bonding evacuation processing module that moves the collet in the Z direction with respect to the collet table to lift and evacuate it from the bonding position.

  According to at least one of the above-described configurations, the collet unit has a collet that holds the chip by suction, a collet table that holds the collet so as to be movable in the axial direction, and a drive source that is attached to the collet table and applies an axial driving force to the collet. And have. At the bonding position, the chip is bonded to the bonding object by applying a driving force for a predetermined time in a first direction in which the collet is pressed toward the bonding object by a driving source while keeping the position of the collet table. Next, when a predetermined time has elapsed at the bonding position, the collet table position is left as it is, and a driving force is applied to the collet in the second direction opposite to the first direction to lift and retract the collet from the bonding position. Let That is, by switching the direction of the driving force from the driving source, the direction is switched between the direction in which the collet is pressed against the collet table and the direction in which the collet is retracted. As a result, only the collet can be retracted without changing the position of the collet stage, and the movement of the collet table that determines the transfer time between the bonding position and the chip supply position is a direct type, which speeds up bonding. Can be achieved.

Thus, according to the present invention, to separate the motion of the collet retracting collet table, you are possible to only retract bonding position placed et the collet by the movement of the collet table as it is. Therefore, the movement of the collet table that determines the transfer time between the bonding position and the chip supply position can be made a direct type, so that the bonding speed can be further increased.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, the bonding apparatus will be described as a thermocompression bonding type die bonding apparatus, but may be another bonding apparatus having an optimum range in bonding time, for example, an ultrasonic bonding apparatus. Further, a bonding apparatus other than die bonding, for example, an apparatus for bonding a chip to a substrate by soldering may be used. Although the bonding operation is described as bonding a chip to a lead frame, the chip may be a general electronic component such as a resistor chip or a capacitor chip in addition to a semiconductor chip. Other circuit boards may be used.

  FIG. 1 is a configuration diagram of the bonding apparatus 10. Although not constituting the bonding apparatus 10, the chips 2 and 3 and the lead frame 4 that are objects of bonding work are also illustrated. The bonding apparatus 10 includes a bonding apparatus main body 20 and a control unit 60 that is connected to each element of the bonding apparatus main body 20 and controls the operation of the entire bonding apparatus 10.

  The bonding apparatus main body 20 includes a collet portion 30 that reciprocates between the chip supply position 6 and the bonding position 8, and a wafer ring 50 that is provided at the chip supply position 6 and holds the chips 3 that are arranged in a diced state. A carrier 52 that holds the lead frame 4 provided at the bonding position 8, a heater base 54 that heats the bonding portion of the lead frame 4, and a collet part 30 provided at the confirmation position 7 in the transport path of the collet part 30. A chip presence / absence sensor 56 for detecting whether or not the chip 2 is held.

  The collet unit 30 includes a collet 32 that can suck the chip 2, and is a member that can move in the X, Y, and Z3 directions shown in FIG. 1 under the control of the control unit 60. A detailed sectional view of the collet portion 30 is shown in FIG. The collet unit 30 includes a collet 32 and a voice coil motor (VCM) 34 provided on the upper part of the collet 32. The collet 32 and the VCM 34 are held by an arm 36, and the arm 36 is attached to a collet table 38. It is done.

  The collet 32 is a substantially cylindrical member, and the uppermost portion is a flange-shaped upper collar portion 42, and a lower collar portion 44 is also provided at an intermediate portion of the cylinder portion. The upper collar portion 42 is made of a magnetic material and has a function of a movable iron core in relation to the VCM 34. A portion having a uniform diameter between the upper collar portion 42 and the lower collar portion 44 is a portion that is supported by a support hole provided in the arm 36 so as to be movable in the Z direction. The tip portion 46 of the collet 32 is a portion that sucks and holds the chip 2, and a through hole 48 that extends straight from the tip portion 46 toward the upper collar portion 42 of the collet 32 inside the cylinder portion is provided. The through hole 48 has a function of allowing a vacuum device (not shown) to be connected to suck the chip 2 and a function of passing light from a light emitting element of a chip presence sensor 56 described later.

  The VCM 34 is supported by the arm 36 and has a magnetic core that can move in the Z direction. The VCM 34 has a movable iron core, and the air core coil 40 wound around the magnetic core 40 is a drive coil. It is a motor element that applies a driving force to the iron core, that is, the collet 32 in the + Z direction or the −Z direction depending on the direction. Both terminals of the air-core coil 40 are connected to the VCMI / F 70 of the control unit 60 by signal lines. For example, when the current direction generates a driving force in the −Z direction, the collet 32 moves in the −Z direction, and the upper collar portion 42 hits the arm 36 and stops there. If the tip of the collet 32 is in contact with the lead frame or the wafer ring before that, the tip of the collet is pressed against the lead frame or the like with a driving force corresponding to the magnitude of the current supplied to the air-core coil 40. In this way, by controlling the current supplied to the VCM 34, the pressing pressure of the collet 32 can be varied. Further, when the direction of the current generates a driving force in the + Z direction, the collet 32 moves in the + Z direction, and the lower collar portion 44 hits the arm 36 and stops there. That is, the collet 32 can be pulled up. The lifting amount of the collet 32 can be defined by the distance between the lower surface of the upper collar portion 42 and the upper surface of the lower collar portion 44 and the length of the collet support portion of the arm 36. For example, the lifting amount can be about 2 mm.

  The arm 36 is a member having a function of supporting the collet 32 in the support hole so as to be movable in the Z direction and attaching the air-core coil 40 so as to constitute the VCM 34 at the upper collar portion 42 of the collet 32. The support hole also supports when the collet 32 is rotated by θ by a rotation mechanism (not shown). By inserting a ring made of a material with good lubricity into the support hole and supporting the outer diameter of the cylindrical portion of the collet 32 with the inner diameter of the ring, the movement in the Z direction and the θ rotation can be performed smoothly. it can.

  The arm 36 is attached to a collet table 38. The collet table 38 is a table that can be moved in the X, Y, and Z3 directions by an XYZ moving mechanism (not shown). The XYZ moving mechanism (not shown) can be specifically configured to include three step motors, that is, an X motor, a Y motor, and a Z motor. Each terminal of these motors is connected to a collet I / F 72 of the control unit 60 by a signal line.

  Returning to FIG. 1 again, the wafer ring 50 sticks and holds the chips 3 separated from each other by dicing on the adhesive sheet, and has a function of a chip supply unit. A defective chip is marked with a defective chip. The wafer ring 50 can be moved in the X direction and the Y direction by an XY moving mechanism (not shown), whereby any chip on the wafer ring can be moved directly below the chip supply position 6. A detection camera (not shown) can be used for accurate positioning and detection of the presence or absence of a defective mark on the chip. Specifically, the XY moving mechanism (not shown) can be configured to include two step motors, an X motor and a Y motor. Each terminal of these motors is connected to the wafering I / F 74 of the control unit 60 by a signal line.

  The carrier 52 is a member that holds the lead frame 4. The carrier 52 can be moved in the Y direction by a Y moving mechanism (not shown), whereby the lead frame can be transported. Specifically, the Y moving mechanism (not shown) can be configured by a step motor. Each terminal of this motor is connected to the carrier I / F 80 of the control unit 60 by a signal line.

  The carrier 52 moves on the heater base 54. The heater base 54 is for heating the lead frame 4 and the chip 2 to a temperature suitable for bonding, and can be constituted by a table with a built-in heater, for example. Each terminal of the heater is connected to the heater I / F of the control unit 60 by a signal line.

  The chip presence / absence sensor 56 is a transmitted light type sensor provided at the confirmation position 7 in the movement path of the collet 32 and can be configured by a combination of a light emitting element and a light receiving element. The arrangement of the light emitting element and the light receiving element is as follows. At the confirmation position 7, the light emitted from the light emitting element passes through the through hole 48 of the collet 32, and if the tip 2 of the collet 32 does not have the chip 2, the light receiving element It is set to receive light. Accordingly, whether the collet 32 holds the chip 2 in the forward conveyance from the chip supply position 6 to the bonding position 8, and the collet 32 takes the chip 2 home in the backward conveyance from the bonding position 8 to the chip supply position 6. It can be confirmed whether or not it is done. The signal line of the chip presence / absence sensor 56 is connected to the presence / absence sensor I / F 76 of the control unit 60.

  Next, the configuration of the control unit 60 will be described. The control unit 60 has a function of controlling each element constituting the bonding apparatus main body 20, and in particular controls the movement of the collet table 38 in the collet unit 30 and the position and pressing pressure of the collet 32 driven by the VCM 34, This is a device having a function of executing a bonding operation at a high speed, and can be constituted by a general computer.

Specifically, the outward transport processing functions to transport the pickup processing function for picking up chips, the collet portion 30 from the chip supply position 6 to bonding location 8 in Chi-up supply position 6 using collet 30, the bonding positions and bonding processing function to perform the bonding in 8, and the return transport processing function for carrying the collet 30 to the bonding position 8 Karachi-up supply position 6 has the chip whether the collet 30 further in the confirmation position 7 It has a confirmation processing function to detect, a bonding evacuation processing function for evacuating the collet 32 at the bonding position 8, and a pickup evacuation processing function for evacuating the collet 32 at the chip supply position 6. Software can be used to perform processing corresponding to these functions, and predetermined processing can be performed by executing a corresponding bonding program. A part of the processing can be executed by hardware.

  The control unit 60 includes a CPU 62, an input unit 64 such as a keyboard, an output unit 66 that is a display such as a display panel, an external storage device 68, and a VCMI / F 70 connected to each element of the bonding apparatus body 20. I / F up to I / F 80 is included, and these are connected to each other via an internal bus.

  The functions of the CPU 62 from the pickup processing module 82 to the pickup withdrawal processing module 94 will be described with reference to the flowchart of FIG. The procedure of the bonding operation shown in FIG. 3 is a direct type for conveying the collet table 38 between the chip supply position 6 and the bonding position. Although the procedure of the bonding operation may be described from any place, in FIG.

  In the pickup step (S10), the collet 32 picks up the chip 2. Specifically, the pickup processing module 82 of the CPU 62 issues an instruction to a vacuum device (not shown), decompresses the portion of the through hole 48 of the collet 32, and moves the chip 2 from the wafer ring 50 to the tip end portion 46 of the collet 32. Hold by suction. Further, an instruction is given to the wafer ring 50, and an operation of pushing the tip from the back side toward the collet 32 in synchronization with the suction of the collet 32 is performed.

  Further, the pickup processing module 82 issues a command to the VCM 34 via the VCMI / F 70, and applies a driving force to the collet 32 toward the wafer ring 50, that is, in the -Z direction shown in FIG. 2, for example, about 400 N in the -Z direction. The pressing pressure is generated. That is, the collet 32 performs vacuum suction while sandwiching the chip 2 with a force of about 400 N in combination with the pushing-up operation of the wafer ring 50. This makes it possible to perform pickup more reliably.

In the forward transfer process (S12), the collet unit 30 is directly transferred from the chip supply position 6 to the bonding position 8 while the chip 2 is sucked and held. Here direct conveyed, for example not contain Toka rises directly above once by sucking chip 2, an operation such as descending beneath therefrom once moved to just above the bonding location 8, the chip from Uefaringu 50 2 In the condition of the arrangement of each element in the bonding apparatus 10 and the like, it does not necessarily mean that it is perpendicular to the shortest distance spatially. It means that it can be transported at the highest speed. Therefore, it may be a parabolic conveyance locus rather than a linear conveyance locus. Specifically, the forward transfer processing module 84 issues an instruction to an XYZ moving mechanism (not shown) via the collet I / F 72, and based on the movement locus that can be transferred from the chip supply position 6 to the bonding position 8 in the shortest time. The collet unit 30 is moved. The maximum acceleration of conveyance can be set to 170-190 m / sec ² , for example.

  At this time, the forward transfer processing module 84 issues a command to the VCM 34 via the VCMI / F 70, and gives the collet 32 a larger driving force in the -Z direction shown in FIG. For example, the mass of the collet 32 is 40-60 grams, and a pressing pressure of about 3500 N is generated in the −Z direction. That is, at the maximum conveyance acceleration, a sufficient pressing pressure is generated so that the collet 32 does not vibrate against the arm 36, and the collet 32, the arm 36, and the collet table 38 are moved together.

  In the pickup step (S10), the relative positional relationship between the collet 32 and the chip 2 is detected by using a detection camera (not shown), and the result is the collet 32 and the lead frame 4 at the bonding position 8. Used for positioning between. Specifically, if the relative positional relationship between the collet 32 and the chip 2 is deviated from the standard by the detection camera, the deviated target end position of the forward path transport process is corrected. If there is an angle shift, correction is performed by rotating the collet 32 by θ for the shift. In this way, the chip 2 held by the collet 32 is transported to a predetermined bonding location on the lead frame 4 while correcting the target end position of the direct transport and the like.

In the bonding step (S14), the collet 32 bonds the chip 2 to the bonding portion of the lead frame 4. The heater base 54 is controlled via the heater I / F 80 so that the bonding portion of the lead frame 4 has a temperature suitable for predetermined bonding. Here, the bonding processing module 86 issues a command to the VCM 34 via the VCMI / F 70 and applies a driving force to the collet 32 in the direction toward the lead frame 4, that is, in the −Z direction shown in FIG. A pressing pressure of 400 N is generated. This command can be issued in the final stage of the forward transfer process in consideration of the response time for switching the current value of the VCM 34. Then, we are held for a predetermined time t ₀ which is suitable for bonding. That is, the chip 2 is pressed against the lead frame 4 at a predetermined bonding temperature with a pressing pressure of about 400 N for a time t ₀ , thereby performing appropriate bonding.

  In the wafer ring 50, the process of bringing the next good chip to the chip supply position 6 is performed while the processes of the forward transfer process (S12) and the bonding process (S14) are performed. From the viewpoint of overall speedup, the time for bringing the next chip after the picked-up position to the chip supply position = the processing time of the forward transfer process (S12), the processing time of the bonding process (S14), and the return transfer process (S18). ), The maximum speed can be achieved. However, with this setting, if the next chip at the picked-up position is defective, the positioning of the next chip on the wafer ring 50 will not be in time.

Therefore, it is determined whether or not the elapsed time ΔT of the bonding process has exceeded a predetermined bonding time t ₀ (S16). When ΔT is equal to or greater than t _{0, the} process proceeds to a bonding save step (S24) described later. Here, a normal case where ΔT does not exceed t ₀ will be described first. At this time, a return path conveyance process (S18) is performed next. That is, the collet unit 30 is conveyed directly from the bonding position 8 to the chip supply position 6. Specifically, the return path transport processing module 88 issues an instruction to an XYZ moving mechanism (not shown) via the collet I / F 72 and is based on a motion trajectory that can be transported from the bonding position 8 to the chip supply position 6 in the shortest time. The collet unit 30 is moved. The maximum acceleration of conveyance can be set to, for example, 170-190 m / sec ^{2 in the} opposite direction to that of the outward conveyance.

  At this time, the return path conveyance processing module 88 issues a command to the VCM 34 via the VCMI / F 70, and gives the collet 32 a larger driving force in the -Z direction shown in FIG. For example, the mass of the collet 32 is 40-60 grams, and a pressing pressure of about 3500 N is generated in the −Z direction. That is, at the maximum conveyance acceleration, a sufficient pressing pressure is generated so that the collet 32 does not vibrate against the arm 36, and the collet 32, the arm 36, and the collet table 38 are moved together.

  If the bonding is normally performed, the collet 32 does not have the chip 2 in the return path transporting step (S18), and is returned to the chip supply position 6 in an empty state. However, in some rare cases, bonding is not successful, and the chip 2 is attracted to the collet 32 and the return path transport process (S18) is entered, so that a so-called chip can be taken home. In order to confirm this, it is confirmed whether or not the collet 32 has no chip at the confirmation position 6 (S20). Specifically, the confirmation processing module 92 issues an instruction to the chip presence / absence sensor 56 via the presence / absence sensor I / F 76, causes the light emitting element to emit light at the confirmation position 6, and passes the light through the through hole 48 of the collet 32. The result is detected by the light receiving element. If the light receiving element detects light, it can be confirmed that the collet 32 has no chip and is normal. If the light receiving element cannot receive light, it is determined that the chip 2 is held at the tip 46 of the collet 32. In the so-called take-away state where the chip is held on the collet 32, the process proceeds to a pickup evacuation step (S26) to be described later. Here, the normal case will be described first.

  If it is determined in the confirmation step (S20) that there is no chip in the collet 32, the return path conveyance process is continued, the collet unit 30 is conveyed to the chip supply position (S22), and then the process returns to the pickup process (S10). In the return path conveying step (S18), the command to the VCM 34 generates a pressing pressure of about 3500 N, but in the pickup step (S10), the pressing pressure of about 400 N is optimal. Although it has been described that the pressing pressure generation command of about 400 N is performed in the pickup process (S10), it may be issued at the final stage of the return path conveyance process (S18) in consideration of the response time of the current value switching of the VCM 34. .

In a normal case, by repeating these steps, the collet portion 30 can be conveyed directly between the chip supply position 6 and the bonding position 8, and the new chip 2 can be sequentially bonded to the new lead frame 4 at high speed. . This is schematically shown in FIG. FIG. 4 is a diagram schematically showing the movement trajectory of the collet unit 30 in the XZ plane, where the horizontal axis represents the distance in the X direction with position coordinates, and the Y axis represents the distance in the Z direction with position coordinates. In FIG. 4, the chip supply position is (X _P , Z _P ), the bonding position is (X _B , Z _B ), and the confirmation position is (X _S , Z _S ). For example, X _P -X _B can be about 4-10 cm and Z _B -Z _P can be about 3 cm. In the case of normal direct conveyance, the collet unit 30 is in a state where the collet is always pressed against the arm unit, that is, the collet stage, and is conveyed as a unit. With this positional relationship, in the example of the direct conveyance in which the acceleration during conveyance is 170-190 m / sec ² , one cycle of bonding work can be completed in about 140 msec.

Next, two cases different from the normal case will be described. The first case is a case where ΔT is determined to be equal to or greater than t ₀ in the step (S16) in which it is determined whether or not the elapsed time ΔT of the bonding process exceeds a predetermined bonding time t ₀ . In this case, when ΔT = t ₀ , the process proceeds to the bonding evacuation step (S24). That is, when the time lapse ΔT of the bonding process exceeds t ₀ at the bonding position, the position of the collet table 38 is left as it is, the direction of the current flowing through the VCM 34 is reversed, and the collet 32 is pulled up from the lead frame 4 and retracted. Let In the above example, the size of the lifting and retracting is about 2 mm. Specifically, the bonding evacuation processing module 90 issues a command to the VCM 34 via the VCMI / F 70, and issues a command to flow a current in the direction opposite to the current direction in the bonding step (S14). The magnitude of the current may be such that the upper surface of the lower collar portion 44 of the collet 32 is pressed against the lower surface of the arm 36. At this time, the command to the XYZ drive mechanism for driving the collet table 38 is not changed. Thus, only the collet 32 can be retracted from the lead frame 4 by about 2 mm without changing the position of the collet table 38. Therefore, the bonding process can be completed at ΔT = t ₀ , no excessive pressing pressure is applied to the lead frame 4 and the chip, and the excessive heating of the collet 32 is not continued.

FIG. 5 is a diagram for schematically explaining the passage of time of the position of the collet and the collet table in the Z direction before and after the bonding is retracted. Time is taken on the horizontal axis, the distance in the Z direction from an arbitrary reference point is taken as the position coordinate on the vertical axis, the locus 132 of the Z position coordinate at the tip of the collet is shown by a broken line, and it is plotted on the corresponding collet table. The locus 138 of the Z position coordinates at an appropriate reference point is indicated by a solid line. For comparison, the locus 133 of the Z position coordinates at the tip of the collet in a normal case is indicated by a two-dot chain line, and the locus 139 of the Z position coordinates at the reference point of the corresponding collet table is indicated by a one-dot chain line. In FIG. 5, since the collet and the collet table are transported together during the forward transport, the collet trajectory 132 and the collet table trajectory 138 are kept at a constant interval. At time t ₁ , the tip at the tip of the collet comes into contact with the lead frame and is pressed with an appropriate pressing pressure to start the bonding process. From the start time t ₁ to the time t ₂ when a time t ₀ determined as a time suitable for bonding elapses, the collet and the collet table remain in their positions, and the lead frame and the chip are set at a predetermined temperature. Bonding is performed while maintaining a predetermined pressing pressure.

In the normal case, the positioning of the next non-defective chip in the wafering proceeds smoothly before the time lapse of the bonding process reaches t _0, and an instruction for the return path conveyance immediately from time t ₂ = t ₁ + t ₀ is given. As shown by the one-dot chain line and the two-dot chain line in FIG. 5, the collet and the collet table are conveyed toward the chip supply position while being integrated.

Here not proceed work smoothly in Uefaringu, when the command for conveying backward even if the time t ₂ is not output at time t _2, and the position of the collet table as it is, to retract the collet only . That is, as shown in FIG. 5, the collet table trajectory 138 does not change, whereas the collet trajectory moves in the + Z direction. Then, the first time the collet table becomes time t ₃ when the instruction for return transport to the collet advances positioning in Uefaringu is issued to start moving. Time t ₄ represents the time at which the collet and the collet table are integrated again. The retreat speed of the collet does not have to be the same as the corresponding ascent speed during the return path conveyance. In addition, a command for carrying the return path may be issued while the collet is retracted.

FIG. 6 shows the state of the return path conveyance after the bonding evacuation process in the same expression as FIG. That is, the Z position of the collet table 38 remains the same at the bonding position X = X _B by the bonding retracting process, but the Z position of the collet 32 is retracted in the + Z direction. Here, when entering the return path conveyance, the position of the collet table does not change depending on the presence or absence of the bonding evacuation process, and therefore, the movement path of the return path conveyance of the collet table is the same as in the normal case of FIG. That is, even in the case of FIG. 6, the collet portion is conveyed straight from the bonding position to the chip supply position as in FIG. 4.

  The second case different from the normal case is a case where it is determined that the collet has a chip in the confirmation step (S20) after the bonding step. At this time, the process proceeds to the pickup evacuation step (S26). That is, when it is determined that the chip is held in the collet, the position of the collet table 38 is left as it is, the direction of the current flowing through the VCM 34 is reversed, and the collet 32 is pulled up with respect to the collet table 38. Move in the direction and evacuate. The pull-up / retraction magnitude ΔZ is about 2 mm in the above example. Specifically, the pickup retreat processing module 94 issues a command to the VCM 34 via the VCMI / F 70, and issues a command to flow a current in the direction opposite to the current direction in the bonding step (S14). The magnitude of the current may be as large as that in the bonding evacuation process. At this time, the command to the XYZ drive mechanism for driving the collet table 38 is not changed. Thus, only the collet 32 can be retracted about 2 mm from the collet table 38 without changing the position of the collet table 38. If the return path conveyance is continued as it is, when the collet unit 30 reaches the chip supply position, the position of the collet table 38 in the Z direction is the same as usual, but the tip of the collet 32 is about 2 mm higher than normal and above the wafer ring. Can be evacuated.

FIG. 7 is a diagram schematically illustrating the passage of time between the collet and the collet table in the Z direction before and after the pickup is retracted. The horizontal and vertical axes are time and position coordinates, respectively, as in FIG. However, FIG. 5 is centered on the bonding position, whereas FIG. 7 is centered on the chip supply position, so the absolute values are different. Here, similarly to FIG. 5, the locus 232 of the Z position coordinates at the tip of the collet is indicated by a broken line, and the locus 238 of the Z position coordinates at the reference point of the collet table corresponding thereto is indicated by a solid line. For comparison, the locus 233 of the Z position coordinate at the collet tip in a normal case is indicated by a two-dot chain line. In FIG. 7, time t ₅ is the time when the confirmation position is reached in the return path conveyance. Since the collet and the collet table are transported as a unit so far, the collet trajectory 232 and the collet table trajectory 238 are kept at a constant interval.

If it is confirmed at time t ₅ that there is a chip, the position of the collet table is left as it is, and only the collet is retracted. That is, as shown in FIG. 7, the collet table trajectory 238 continues to move as it is, whereas the collet moves in the + Z direction with respect to the collet table, so the collet trajectory 232 keeps a constant distance from the collet table trajectory 238. It disappears. When the collet is moved until it hits the arm at time t _6, then the collet and collet table is moved together in that state, and reaches the chip supply position at time t _6. In FIG. 7, the collet trajectory 233 in the normal case is indicated by a two-dot chain line, but the Z position of the collet is set to a height at which the chip can be picked up from the wafer ring at time t ₆ . Compared to the position in the case of this normal position of the collet in the optical pickup retracted state it would have retracted to a position higher by + [Delta] Z. The size of the retracted amount ΔZ is about 2 mm in the above example, which is the same as that when the bonding is retracted. Thereafter, a pick-up process is performed, and after the pick-up process is completed at time t ₇ , the forward transfer is started. Time t ₈ represents the time when the collet and the collet table are integrated again. Incidentally, retracting speed of the collet is not particularly limited as long as the extent in time to the collet is sufficiently retracted at time t _6.

  FIG. 8 shows a state in which the chip is taken home in the return path conveyance with the same expression as FIG. 4 and FIG. The chip presence / absence sensor 56 detects that there is a chip in the collet. As a result, the collet 32 is relatively retracted from the collet table 38, and at the chip supply position, the tip of the collet 32 that has returned the chip 2 retracts sufficiently upward from the upper surface of the wafer ring. Thereby, even if the take-out chip is held by the collet, it is possible to prevent the wafer from colliding with the wafer ring or another chip disposed thereon at the chip supply position. In this case, the Z position of the collet table 38 is moved according to the original transport locus without any correction, and is the same as the normal case of FIG. That is, in the case of FIG. 8 as well, the collet portion is conveyed straight from the bonding position to the chip supply position as in FIG.

  In this way, by appropriately controlling the direction of current flowing through the VCM 34 and the magnitude of the current for each step of bonding, the collet portion 30 has a small mass and is suitable for the collet 32 having little influence on the conveyance speed. A pressing pressure can be applied, and an appropriate evacuation can be performed. Since the movement of the collet 32 can be controlled independently of the collet table 38 and the like, the collet table 38 having a large inertia and having a large influence on the conveyance speed in the collet unit 30, and the arm 36 fixed to the collet table 38, the VCM 34 and the like are conveyed. The trajectory can be set under optimal high-speed transport conditions.

It is a block diagram of the bonding apparatus in embodiment which concerns on this invention. It is a detailed sectional view of a collet part in an embodiment concerning the present invention. It is a flowchart which shows the procedure of bonding in embodiment which concerns on this invention. In embodiment which concerns on this invention, it is a figure which shows typically the movement locus | trajectory of a collet part. In embodiment which concerns on this invention, it is a figure which illustrates typically the position locus | trajectory of the Z direction of the collet and collet table before and behind bonding evacuation. In embodiment which concerns on this invention, it is a figure which shows the mode of a return path conveyance after a bonding evacuation process. In embodiment which concerns on this invention, it is a figure which illustrates typically the position locus | trajectory of the Z direction of the collet and collet table before and behind pick-up retraction | saving. In embodiment which concerns on this invention, it is a figure which shows a mode when there exists a take-away of a chip | tip in a return path | pass conveyance.

Explanation of symbols

  2, 3 chips, 4 lead frame, 6 chip supply position, 7 confirmation position, 8 bonding position, 10 bonding apparatus, 20 bonding apparatus body, 30 collet part, 32 collet, 34 VCM, 36 arm, 38 collet table, 40 air core Coil, 56 chip presence sensor, 60 control unit, 62 CPU, 82 pickup processing module, 84 forward transfer processing module, 86 bonding processing module, 88 return path transfer processing module, 90 bonding evacuation processing module, 92 confirmation processing module, 94 pickup evacuation Processing module, 132, 133, 232, 233 Collet trajectory, 138, 139, 238 Collet table trajectory.

Claims (3)

X held movably collet for sucking holding the chip in the Z-direction, Y, and Z3 direction movable collet table, a collet drive source that is attached to the collet table to collet table collet in the Z direction using the collet for closed and a driving source providing a driving force to move the,
A pick-up process for picking up a chip by a collet at a chip supply position;
From the chip supply position to the bonding position , based on the movement trajectory in the X, Y, Z3 direction, the collet and the collet table are integrated, and the forward conveyance process of conveying the collet part directly;
At the bonding position, the position of the collet table is left as it is, the driving source is used to move the collet in the Z direction with respect to the collet table and apply the driving force in the first direction to press it against the object to be bonded for a predetermined time. A bonding process for bonding to an object;
From the bonding position to the chip supply position , based on the movement trajectory in the X, Y, and Z3 directions, the collet and the collet table are integrated, and the return conveyance process for conveying the collet part directly;
In a bonding method including:
When a predetermined time has elapsed at the bonding position, the collet table is left in the same position, and a driving force is applied to the collet in the second direction opposite to the first direction to move the collet in the Z direction with respect to the collet table. A bonding method comprising: a bonding evacuation step of lifting and evacuating from a bonding position. X held movably collet for sucking holding the chip in the Z-direction, Y, and Z3 direction movable collet table, a collet drive source that is attached to the collet table to collet table collet in the Z direction using the collet for closed and a driving source providing a driving force to move to, the collet portion a bonding program to be executed by a bonding apparatus back and forth and bonding is performed between the chip supply position and the bonding position,
Pickup processing procedure for picking up a chip by a collet at a chip supply position;
From the chip supply position to the bonding position , based on the movement trajectory in the X, Y, Z3 directions, the collet and the collet table are integrated, and the forward conveyance process procedure for conveying the collet part directly;
At the bonding position, the collet table position is left as it is, the collet is moved in the Z direction by the drive source with respect to the collet table, and a driving force is applied in a first direction for pressing the bonding target object for a predetermined time, and the chip is bonded. Bonding procedure for bonding to objects,
From the bonding position to the chip supply position , based on the movement trajectory in the X, Y, and Z3 directions, the collet and the collet table are integrated, and the return path conveyance processing procedure for conveying the collet portion directly;
Including
When a predetermined time has elapsed at the bonding position, the collet table is left in the same position, and a driving force is applied to the collet in the second direction opposite to the first direction to move the collet in the Z direction with respect to the collet table. A bonding program for executing a bonding evacuation processing procedure for lifting and evacuating from a bonding position. A bonding apparatus that includes a collet unit that holds a chip and a control unit, and performs bonding by reciprocating the collet unit between a chip supply position and a bonding position;
The collet section
A collet for sucking and holding the tip;
X holds the collet to be movable in the Z-direction, a movable collet table Y, Z3 direction,
A driving source providing a driving force for moving the collet in the Z direction relative to the collet table a collet drive source that is attached to the collet table,
Have,
A control unit is,
A pick-up processing module for picking up a chip by a collet at a chip supply position;
From the chip supply position to the bonding position , based on the movement trajectory in the X, Y, and Z3 directions, the collet and the collet table are integrated, and the forward conveyance processing module that conveys the collet straightly;
At the bonding position, the collet table position is left as it is, the collet is moved in the Z direction by the drive source with respect to the collet table, and a driving force is applied in a first direction for pressing the bonding target object for a predetermined time, and the chip is bonded. A bonding processing module for bonding to objects,
From the bonding position to the chip supply position , based on the movement trajectory in the X, Y, Z3 directions, the collet and the collet table are integrated, and the return path conveyance processing module that conveys the collet section directly;
Including
When a predetermined time has elapsed at the bonding position, the collet table is left in the same position, and a driving force is applied to the collet in the second direction opposite to the first direction to move the collet in the Z direction with respect to the collet table. A bonding apparatus comprising: a bonding evacuation processing module that is lifted and evacuated from a bonding position.

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