JP2017120824A - Die bonder and die bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die bonder having a good accuracy of bonding position in the plane direction, at the time of first bonding or first bonding when elapsing a predetermined time after reciprocal operation, and to provide a bonding method.SOLUTION: A die bonder has a collet for holding a chip by abutting against a chip-compatible surface, i.e., the surface of an insulation material, picks up the chip at the pick-up position by means of the collet, bonds the chip to a substrate while heating at the bonding position, and reciprocates between the pick-up position and bonding position. The die bonder is provided with surface heating means for reducing the temperature difference between the temperature of the chip-compatible surface before the first pick-up or before the first pick-up when elapsing a predetermined time after reciprocal operation, and the temperature of the chip-compatible surface before bonding during continuous operation, compared with the temperature difference when not heating.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a die bonder and a bonding method.

  In the manufacture of semiconductor devices, a chip bonding technique in which a wafer on which a large number of elements are fabricated is diced and separated into individual semiconductor chips, which are bonded one by one to a predetermined position such as a lead frame. Is adopted. A die bonder is used for this chip bonding (Patent Document 1). The die bonder includes a bonding arm that can move between a pickup position 100 (see FIG. 4) and a bonding position 101 (see FIG. 4) via a conveying means, and the tip of the bonding arm is as shown in FIG. Further, a collet 103 that holds the semiconductor chip 102 (hereinafter referred to as the chip 102) is held.

  As shown in FIG. 4, the collet 103 includes a rubber (heat insulating material) 104 made of, for example, fluororubber, and a holder 105 that pressurizes and holds the rubber 104 from the side surface. The rubber 104 has a suction hole (not shown) opened at its lower end surface, and the chip 102 is vacuum-sucked through the suction hole, and the lower end surface of the rubber 104 becomes the chip corresponding surface 106 so that the chip The chip 102 is attracted to the corresponding surface 106. If this vacuum suction is released, the chip 102 is detached from the collet 103.

  Incidentally, the chip 102 may be bonded while being heated at the bonding position 101. For example, a film adhesive (die attach film) that acts as an adhesive by heating is attached to the back surface of the chip 102. When bonding such a chip, first, a pick-up position 100 at room temperature is used. To pick up chip 102. The bonding stage 107 has a heater function, and bonds the chip 102 to the bonding position 101 at a high temperature. As described above, there is a temperature difference between the pickup position 100 and the bonding position 101, and the collet 103 repeats reciprocation between normal temperature and high temperature.

JP 2000-68296 A

  As described above, when the collet 103 repeats reciprocation between normal temperature (pickup position 100) and high temperature (bonding position 101), the temperature of the chip-corresponding surface 106 of the collet 103 increases each time bonding is performed. That is, as shown in FIG. 5, the temperature of the chip corresponding surface 106 is substantially normal temperature at the first pick-up p1, and the chip corresponding surface 106 is bonded to the bonding stage 107 after b1 immediately before the first bonding start. As a result, the temperature of the chip corresponding surface 106 becomes higher than the normal temperature. In FIG. 5, pn represents the n-th pick-up, bn represents the time immediately before the n-th bonding start, and bn ′ represents the n-th bonding end. Further, t (bn) indicates the temperature of the chip corresponding surface 106 immediately before the start of the n-th bonding.

  When the reciprocating operation between the pickup and bonding is repeated, the temperatures t (b2), t (b3), t (b4), and t (b5) of the chip corresponding surface 106 immediately before the start of bonding are as shown in FIG. Rise in steps. Thereafter, when the temperature of the chip-corresponding surface 106 immediately before the start of bonding reaches a certain temperature tc (in FIG. 5, b6 immediately before the start of bonding b6), thereafter, the reciprocating operation is performed as long as the reciprocating operation is continuously performed. The temperature of the chip-corresponding surface 106 immediately before the start of bonding is substantially constant until the process is completed (in FIG. 5, tc = t (b6) ≈t (b7) ≈t (b8)...).

  When starting from a state where the apparatus is stopped, or when restarting after interruption of the reciprocating operation due to a ring change operation or the like, the chip corresponding surface 106 is substantially at room temperature. Therefore, the temperature of the chip corresponding surface 106 before bonding until the temperature of the chip corresponding surface 106 before bonding reaches tc (in FIG. 5, t (b1), t (b2), t (b3), t ( b4) and t (b5)) are lower than the temperature of the chip corresponding surface 106 immediately before the start of subsequent bonding (t (b6), t (b7), t (b8)... in FIG. 5). It becomes.

  When the temperature of the chip corresponding surface 106 before bonding is low, the rubber 104 is thermally contracted. For this reason, when the chip 102 is held by the collet 105, the position of the chip 102 in the planar direction with respect to the chip corresponding surface 106 is different from that during continuous operation (after b6 in FIG. 5), and the bonding position of the chip 102 is shifted. In particular, before the first bonding, the temperature t (b1) of the chip corresponding surface 106 is low, and the rubber 104 is in the most thermally contracted state. For this reason, there is a problem that the accuracy of the bonding position in the planar direction is deteriorated particularly at the start of operation (that is, when the temperature of the chip corresponding surface 106 starts from around room temperature).

  Therefore, in view of such a situation, the present invention provides a die bonder and a bonding method in which the bonding position accuracy in the planar direction is high at the time of the first bonding after the predetermined time has passed after the first bonding or the reciprocating operation. is there.

  The die bonder of the present invention has a collet that holds the chip in contact with the chip-corresponding surface with the surface of the heat insulating material as the chip-corresponding surface, and picks up the chip at the pick-up position with the collet and heats it at the bonding position. In the die bonder that bonds the chip to the base material and reciprocates between the pick-up position and the bonding position, the chip-corresponding surface is placed on the chip side before the first pick-up before the first pick-up or after a predetermined time after the reciprocating operation. The temperature difference between the temperature of the chip corresponding surface before the first bonding before the first bonding or after the predetermined time after the reciprocating operation and the temperature of the chip corresponding surface before the bonding during continuous operation is heated. Surface heating means to reduce the temperature difference when not Those digits. Here, the term “before bonding” refers to a period from when a chip is picked up by a collet to bonding, and a state in which the chip is held by the collet. The temperature of the chip-corresponding surface before bonding during continuous operation is the maximum temperature that the chip-corresponding surface reaches before bonding during continuous operation of reciprocating operation (bonding of the chip-corresponding surface reached by heating by bonding). As long as it is the previous maximum temperature and the reciprocating operation is performed continuously, it is almost constant until the reciprocating operation is completed.

  According to the die bonder of the present invention, the surface heating means is provided, and the chip-corresponding surface of the collet can be heated from the chip side before the first pickup or before the first pickup after a predetermined time has elapsed after the reciprocating operation. As a result, even when starting the reciprocating operation from a state in which the chip-corresponding surface is at almost normal temperature, such as when starting from the device stop state or when restarting after interrupting the reciprocating operation due to ring change operation etc. The temperature of the chip corresponding surface before the first bonding can be brought close to the temperature of the chip corresponding surface before bonding during continuous operation. Thereby, before the first bonding, generation | occurrence | production of the thermal contraction of a heat insulating material can be suppressed. For this reason, when the chip is held by the collet, it is possible to prevent the displacement of the chip in the planar direction with respect to the heat insulating material (chip-corresponding surface), and to suppress the displacement of the bonding position of the chip before the first bonding. .

  In the above configuration, the surface heating means is configured to calculate a temperature of the chip corresponding surface before the first bonding before the first bonding or a predetermined time after the reciprocating operation and a temperature of the chip corresponding surface before the bonding during the continuous operation. The temperature difference between the chip holding surface chip holding position before the first bonding after the first bonding or a predetermined time after the reciprocating operation, and the chip holding surface chip holding position before the bonding during continuous operation. The temperature of the chip-corresponding surface before the first pick-up before the first pick-up or after a predetermined time elapses after the reciprocating operation can be set so as to be within a range where no positional deviation occurs.

  The said structure WHEREIN: The said surface heating means can be made into the heating stage which has a larger flat surface than the said chip | tip corresponding surface.

  The said structure WHEREIN: The control means which heats the said surface heating means when there is no reciprocation for predetermined time can be provided.

  In the bonding method of the present invention, the surface of the heat insulating material is used as a chip-corresponding surface, the collet that holds the chip in contact with the chip-corresponding surface, picks up the chip at the pick-up position, and heats it to the substrate while heating at the bonding position. In a bonding method of bonding a chip and reciprocating between the pickup position and the bonding position, the chip-corresponding surface is heated from the chip side before the first pickup or before the first pickup after a predetermined time has elapsed after the reciprocation. The temperature at which the temperature of the chip corresponding surface before the first bonding before the first bonding or after the predetermined time has elapsed after the reciprocating operation and the temperature of the chip corresponding surface before the bonding during continuous operation is not heated. It will be less than the difference.

  In the above configuration, the temperature difference between the temperature of the chip corresponding surface before the first bonding or before the first bonding after a predetermined time has elapsed after the reciprocating operation and the temperature of the chip corresponding surface before the bonding during continuous operation is the first difference. Range in which there is no misalignment between the chip holding position of the chip-corresponding surface before bonding or the first bonding after the predetermined time has passed after the reciprocating operation and the chip holding position of the chip-corresponding surface before bonding during continuous operation It is possible to set the temperature of the chip-corresponding surface before the first pickup or before the first pickup after a predetermined time has elapsed after the reciprocating operation.

  The said structure WHEREIN: A heating surface larger than the said chip | tip corresponding surface can be made to contact a chip | tip corresponding surface, and the said chip | tip corresponding surface can be heated.

  In the above configuration, the chip-corresponding surface can be heated when there is no reciprocation for a predetermined time.

  In the present invention, the accuracy of the bonding position in the planar direction is improved in the first bonding after the predetermined time has elapsed after the first bonding or the reciprocating operation.

It is a simplified front view which shows the die bonder of this invention. It is a graph which shows the temperature change of the chip | tip corresponding surface at the time of reciprocating using the die bonder of this invention. It is a graph which shows the other temperature change of the chip | tip corresponding surface at the time of reciprocating using the die bonder of this invention. It is a simplified front view which shows the conventional die bonder. It is a graph which shows the temperature change of the chip | tip corresponding surface at the time of reciprocating using a conventional die bonder.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the die bonder of the present invention includes a bonding arm (not shown) that can move between a pickup position 1 and a bonding position 2. The collet 5 that adsorbs the chip 4) is held.

  The collet 5 carries the chip 4 by reciprocating between the pickup position 1 and the bonding position 2 as shown by an arrow B in FIG. As shown in FIG. 1, the collet 5 includes an adsorption member 6 and a metal holder 7 that holds the adsorption member 6.

  The adsorbing member 6 is composed of a heat insulating material having a uniform wall thickness in the vertical direction. More specifically, the adsorbing member 6 is a rubber component made of natural rubber or synthetic rubber, and is made of fluororubber in this embodiment. As shown in FIG. 1, the lower surface of the adsorption member 6 is a flat surface, and this surface becomes the chip corresponding surface 8 with which the chip 4 abuts. The suction member 6 is provided with a suction hole (not shown) that opens in the chip-corresponding surface 8, and a vacuum generator (not shown) is connected to the suction hole. When the air in the suction hole is sucked by driving the vacuum generator, the chip 4 is vacuum sucked and the chip 4 is sucked onto the chip corresponding surface 8. When this vacuum suction is released, the chip 4 is detached from the chip corresponding surface 8.

  As shown in FIG. 1, the holder 7 includes a shaft portion 9 and a flange portion 10 that is integral with the lower end portion of the shaft portion 9, and has a claw portion 11 integrally on the lower surface of the flange portion 10. The claw part 11 pressurizes the side surface of the suction member 6 so that the holder 7 holds the suction member 6.

  The pickup position 1 is substantially at normal temperature, and a large number of chips 4 are placed on the pickup stage 12. In this embodiment, the pickup stage 12 is an alignment stage (so-called intermediate stage). However, the present invention is not limited to this, and any stage may be used as long as the chip 4 is placed before bonding. A film adhesive (die attach film) that acts as an adhesive when heated is attached to the back surface of the chip 4 on the pickup stage 12.

  In the bonding position 2, a base material 14 such as a lead frame is placed on a bonding stage 13 having a heater function. The chip 4 picked up by the collet 5 at the pickup position 1 is transported to the bonding position 2. The chip 4 transported to the bonding position 2 is heated by the bonding stage 13 and the chip 4 is bonded to the base material 14 by the die attach film acting as an adhesive. Thereafter, the collet 5 returns to the pickup position 1, picks up the chip 4 by the above-described method, and then bonds. In this way, the collet 5 reciprocates between the pickup position 1 and the bonding position 2 as indicated by an arrow B in FIG.

  A surface heating means 15 is provided between the pickup position 1 and the bonding position 2 to heat the chip-corresponding surface 8 from the chip side (that is, the lower side of the suction member 6). Means for heating 8 is provided. In many cases, the base material 14 is present at the bonding position 2 or the chips 4 are stacked on the base material 14, and it is difficult to heat other than the base material 14 and the chips 4 with the heater at the bonding position 2. . Therefore, surface heating means 15 for heating the chip corresponding surface 8 is provided. In the present embodiment, the surface heating means 15 is constituted by a heating stage 16 having a flat surface larger than the chip corresponding surface 8. Thereby, when the chip corresponding surface 8 comes into contact with the heating stage 16, the chip corresponding surface 8 is uniformly heated by the heating stage 16. Further, by providing the surface heating means 15 between the pickup position 1 and the bonding position 2, the stroke of the collet 5 can be minimized and the entire apparatus can be made compact.

  Prior to the start of operation (first pickup) or before the start of re-operation (first pickup after a lapse of a predetermined time after the reciprocating operation), the collet 5 is positioned on the heating stage 16 and is placed on the heating stage 16 in a high temperature state. Then, the chip-corresponding surface 8 of the collet 5 is brought into contact (state shown in FIG. 1). The temperature of the heating stage 16 and the time for which the chip corresponding surface 8 is brought into contact with the heating stage 16 are arbitrarily set by the user depending on the material and size of the suction member 6. Hereinafter, the operation start includes the re-operation start, and the first pickup includes the first pickup after a predetermined time has elapsed after the reciprocating operation. Further, the predetermined time elapses is the time until the chip-corresponding surface 8 that has become high temperature in the reciprocating operation returns to room temperature, and differs depending on the material and size of the suction member 6.

  As shown in FIG. 2, the temperature of the chip corresponding surface 8 rises to T (B0) at a certain point B0 before the first pickup P1. Then, the collet 5 picks up the chip 4 at the pickup position 1 as indicated by an arrow A in FIG. At this time, the temperature of the chip corresponding surface 8 is lowered by the first pickup P1. In FIG. 2, Pn represents the n-th pick-up, Bn represents the time immediately before the n-th bonding start, and Bn ′ represents the n-th bonding end. T (Bn) represents the temperature of the chip corresponding surface 8 just before the start of the n-th bonding. Furthermore, a two-dot chain line indicates a temperature change of the chip corresponding surface 8 when the chip corresponding surface 8 is not heated, and corresponds to the graph of FIG.

  Thereafter, the collet 5 bonds the chip 4 at the bonding position 2. At this time, the temperature T (B1) of the chip-corresponding surface B1 immediately before the start of the first bonding falls to a certain temperature Tc, as shown in FIG. 2, but b1 immediately before the start of the first bonding without heating. It becomes higher than the temperature t (b1) of the chip corresponding surface 8. In this case, the temperature Tc is the highest temperature reached by the chip corresponding surface 8 before bonding during continuous operation of reciprocating operation (the highest temperature during bonding of the chip corresponding surface 8 reached by heating during bonding). As long as the reciprocating operation is performed continuously, it is almost constant until the reciprocating operation is completed). The term “before bonding” refers to a period from when a chip is picked up by a collet until bonding, and a state in which the chip is held by the collet. In the present embodiment, “before bonding” refers to the time immediately before the start of bonding (that is, the moment before bonding the chip to the bonding position).

  In this way, the surface heating means 15 heats the chip corresponding surface 8 from the chip side before the first pickup P1, thereby the temperature T (B1) of the chip corresponding surface 8 at the time B1 immediately before the start of the first bonding, The temperature difference ΔT with respect to the temperature Tc of the chip corresponding surface 8 immediately before the start of bonding during continuous operation (that is, Tc−T (B1), where ΔT is close to 0 in FIG. 2) is the temperature difference Δt when not heated. (That is, tc−t (b1)).

  Thereby, when starting the reciprocating operation from the state where the chip-corresponding surface 8 is almost at room temperature, such as when starting from the device stop state or when restarting after interrupting the reciprocating operation due to the ring change operation etc. In addition, the temperature T (B1) of the chip corresponding surface 8 at B1 immediately before the start of the first bonding can be made closer to the temperature Tc of the chip corresponding surface 8 immediately before the start of bonding during continuous operation. Thereby, at the time B1 immediately before the start of the first bonding, the heat shrinkage of the adsorption member 6 can be suppressed, and when the chip 4 is held by the collet 5, the position of the chip 4 in the plane direction with respect to the chip corresponding surface 8 Deviation can be prevented.

  As shown in FIG. 1, the surface heating unit 15 is ON / OFF controlled by the control unit 17. The control means 17 is, for example, a microcomputer in which a ROM (Read Only Memory), a RAM (Random Access Memory), and the like are connected to each other via a bus with a central processing unit (CPU) as a center. The ROM stores programs executed by the CPU and data. The control means 17 controls the surface heating means 15 to be heated when there is no reciprocation for a predetermined time (for example, 1 second). The predetermined time can be arbitrarily set by the user. That is, the time for returning to room temperature after the temperature of the chip-corresponding surface 8 rises differs depending on the material and size of the adsorption member 6. For this reason, a user grasps | ascertains the time until the chip | tip corresponding surface 8 returns to normal temperature for every adsorption member 6 to be used, and sets the time according to the adsorption member 6 to be used. Further, when the control means 17 is provided with a table in which the types of the suction members 6 are associated with the respective predetermined times, and the user designates the types of the suction members 6 to be used, the control means 17 sets the corresponding predetermined times. It is good also as a structure set up automatically.

  In the embodiment of FIG. 2, the temperature difference ΔT (= Tc−T (B1)) is set to approximately 0, but ΔT may not be 0 as shown in FIG. That is, the temperature T (B1) of the chip corresponding surface 8 at B1 immediately before the start of the first bonding may not be Tc. In this case, the surface heating means 15 may raise the temperature of the chip corresponding surface 8 before the first pickup P1 so that the temperature difference ΔT is within the range H as shown in FIG.

  In the range H, no positional deviation occurs between the holding position of the chip 4 on the chip corresponding surface 8 immediately before the first bonding start B1 and the holding position of the chip 4 on the chip corresponding surface 8 immediately before the start of bonding during continuous operation. It is a range. That is, if the temperature of the chip corresponding surface 8 immediately before the start of bonding is too lower than Tc, the adsorption member 6 is thermally contracted, and this thermal contraction causes a shift of the holding position of the chip 4 on the chip corresponding surface 8. . In this case, even if the temperature of the chip-corresponding surface 8 immediately before the start of bonding is different from Tc, the difference is such that thermal contraction does not occur, or even if thermal contraction occurs, the chip 4 on the chip-corresponding surface 8 If the difference does not affect the holding position, the accuracy of the bonding position in the planar direction does not deteriorate. That is, the range H is a temperature difference ΔT (that is, a difference between Tc and T (B1)) that does not cause thermal contraction, or even if thermal contraction occurs, the chip on the chip corresponding surface 8 4 is a range that does not affect the holding position. This range H can be arbitrarily set by the user depending on the material and size of the adsorption member 6.

  Thus, the surface heating means 15 sets the temperature T (B0) of the chip corresponding surface 8 before the first pick-up so that the temperature difference ΔT is within the range H, so that the temperature T (B1) becomes Tc. Even if they are different from each other, the positional deviation between the holding position of the chip 4 on the chip corresponding surface 8 immediately before the start of the first bonding B1 and the holding position of the chip 4 on the chip corresponding surface 8 immediately before the start of bonding during continuous operation. Will not occur.

  The die bonder and bonding method of the present invention can suppress the deviation of the bonding position of the chip 4 at the first bonding after the predetermined time has elapsed after the first bonding or reciprocating operation, and the bonding position in the planar direction can be suppressed. The accuracy will be good.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the temperature T (B1) is higher than the temperature Tc. Also good. The surface heating means 15 is desirably a stage in terms of uniformly heating the chip-corresponding surface 8, but may be one that sprays a high-temperature gas or the like on the chip-corresponding surface 8. The position of the surface heating means 15 is preferably between the pickup position 1 and the bonding position 2 in terms of space saving, but is not limited to this position. Moreover, the chip | tip 4 is not what the die attach film was affixed, and may be a paste-form adhesive etc., if a heating is required at the time of joining. As a heating means at the time of bonding, the bonding stage 13 does not need to have a heater function, and a heating means may be provided separately from the bonding stage 13. The control means 17 may be omitted.

DESCRIPTION OF SYMBOLS 1 Pickup position 2 Bonding position 4 Chip 5 Collet 6 Adsorption member 8 Chip corresponding surface 14 Base material 15 Surface heating means 16 Heating stage 17 Control means H Range T Temperature ΔT Temperature difference

Claims (8)

The surface of the heat insulating material is a chip-compatible surface, and it has a collet that holds the chip in contact with the chip-compatible surface. With the collet, the chip is picked up at the pickup position and heated at the bonding position to the chip on the substrate. In the die bonder that reciprocates between the pickup position and the bonding position,
Before the first pick-up or after the predetermined time has elapsed after the reciprocating operation, before the first pick-up, the chip-corresponding surface is heated from the chip side and before the first bonding or after the predetermined time has elapsed after the reciprocating operation. A die bonder comprising a surface heating means for reducing the temperature difference between the temperature of the chip corresponding surface in the step and the temperature of the chip corresponding surface before bonding during continuous operation, compared to the temperature difference when not heating. The surface heating means includes
The temperature difference between the temperature of the chip-corresponding surface before the first bonding before the first bonding or after a predetermined time has elapsed after the reciprocating operation and the temperature of the chip-corresponding surface before the bonding during the continuous operation is The position of the chip holding surface on the chip corresponding surface before the first bonding after a predetermined time has elapsed after the operation and the position of the chip holding surface on the chip corresponding surface before bonding during continuous operation are within a range in which no positional deviation occurs. 2. The die bonder according to claim 1, wherein the temperature of the chip-corresponding surface is set before the first pickup or before the first pickup after a predetermined time has elapsed after the reciprocating operation.   The die bonder according to claim 1 or 2, wherein the surface heating means is a heating stage having a flat surface larger than the chip-corresponding surface.   The die bonder according to any one of claims 1 to 3, further comprising control means for heating the surface heating means when there is no reciprocation for a predetermined time. The surface of the heat insulating material is the chip-compatible surface, and the collet that holds the chip in contact with the chip-compatible surface picks up the chip at the pickup position, bonds the chip to the substrate while heating at the bonding position, and picks up the position. In the bonding method that reciprocates between the bonding position and
Before the first pick-up or after the predetermined time has elapsed after the reciprocating operation, before the first pick-up, the chip-corresponding surface is heated from the chip side and before the first bonding or after the predetermined time has elapsed after the reciprocating operation. A bonding method characterized in that the temperature difference between the temperature of the chip-corresponding surface and the temperature of the chip-corresponding surface before bonding during continuous operation is made smaller than the temperature difference when not heating. The temperature difference between the temperature of the chip-corresponding surface before the first bonding before the first bonding or after a predetermined time has elapsed after the reciprocating operation and the temperature of the chip-corresponding surface before the bonding during the continuous operation is The position of the chip holding surface on the chip corresponding surface before the first bonding after a predetermined time has elapsed after the operation and the position of the chip holding surface on the chip corresponding surface before bonding during continuous operation are within a range in which no positional deviation occurs. 6. The bonding method according to claim 5, wherein the temperature of the chip-corresponding surface is set before the first pickup or before the first pickup after a predetermined time has elapsed after the reciprocating operation.   The bonding method according to claim 5 or 6, wherein a heating surface larger than the chip corresponding surface is brought into contact with the chip corresponding surface to heat the chip corresponding surface.   The bonding method according to claim 5, wherein the chip-corresponding surface is heated when there is no reciprocation for a predetermined time.

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