JP6632856B2 - Bonding head and mounting equipment - Google Patents

Description

  The present invention relates to a bonding head used for heat-pressing an electronic component such as a semiconductor chip on a wiring board or the like, and a mounting apparatus having the same.

  As a method for mounting an electronic component such as a semiconductor chip on a substrate such as a wiring board, a flip chip method is known. In the flip chip method, the electrodes of the electronic component and the electrodes of the substrate are joined by thermocompression bonding using a mounting apparatus 1 as shown in FIG.

  In the mounting apparatus 1 of FIG. 7, first, the electronic component C is arranged at the tip of the bonding head 2 by an electronic component delivery mechanism (not shown), and is held by the bonding head 2. After that, the alignment marks provided on the substrate B held on the substrate stage 4 and the alignment marks provided on the electronic component C are recognized by the image recognition means 5, and the alignment is performed. At the time of positioning, at least one of the bonding head 2 and the substrate stage 4 is moved in an in-plane direction (XY direction and θ direction) parallel to the substrate B. After the alignment, the bonding head 2 is moved down by the bonding unit 3, and the electronic component C is pressure-bonded to the substrate B while heating and heating, so that the electrode of the electronic component C and the electrode of the substrate B are joined. When the joining is completed, the bonding head 2 releases the holding of the electronic component C, moves up by the bonding unit 3, holds the electronic component C to be mounted next at the tip, and performs the above-described series of operations.

  Here, the bonding head 2 has a configuration as shown in FIG. That is, the bonding head 2 includes an attachment tool 20 that suction-holds the electronic component C on the lower surface, a heater 21 disposed above the attachment tool 20, and a heat insulating block 22 disposed above the heater 21. The electronic component C is heated by heating the heater 21, and in order to efficiently supply the heat of the heater 21 to the electronic component C, a heat insulating block 22 is provided to suppress heat transfer above the heater 21. ing. Further, the heat insulating block 22 is connected to a head main body 24 via a holder 23.

  In the flip-chip method, a solder bump is often used as an electrode of an electronic component, and the electronic component that has been heated and pressed on a substrate needs to be cooled until the solder is in a solid state. In recent years, a thermosetting adhesive layer is provided in advance on the surface of the electronic component on the electrode side, and a method of curing the thermosetting adhesive layer during thermocompression bonding has been adopted. In the method, at the stage of holding the electronic component, the temperature of the attachment tool must be lower than the curing start temperature of the thermosetting adhesive layer. For this reason, in a series of tact times, the ratio of time for cooling the heated attachment tool (and the heater) is increasing, and effective cooling means is required from the viewpoint of shortening the tact time.

  For example, Patent Literature 1 introduces a method of air cooling using a cooling blow nozzle provided with an attachment tool and a heater around it. However, in this method, a temperature difference occurs between the air-cooled surface and the inside, so that a significant reduction in the time for cooling to the inside cannot be expected.

  Therefore, a method has been proposed in which a plurality of grooves are provided in a heater, and cooling air is flown from inside the heater into a flow path formed by overlapping the heater and the heat insulating block to cool the heater (for example, Patent Document 2).

  One example is shown in FIG. FIG. 9 shows the heater 21 and the heat insulating block 22 in the bonding head 2 shown in FIG. Also. FIG. 10 and FIG. 11 are three views showing the shapes of the heater 21 and the heat insulating block 22 that constitute the portion shown in FIG. As shown in FIG. 10, a plurality of grooves 21U are provided on the upper surface of the heater 21, and a plurality of tubular flow paths 21P are formed by overlapping the heat insulating block 22 and the heater 21 shown in FIG. On the other hand, the heat insulating block 22 is formed with a depression 22D extending over all the grooves 21U of the heater 21 and provided with a ventilation hole 22V connected to the depression 22D. For this reason, by sending the cooling air to the ventilation holes 22V, the cooling air flows from the vicinity of the center of the heater 21 to both side surfaces (front and rear in FIG. 9), and the heater 21 is cooled from the inside. In FIGS. 9 and 10, the groove 21U and the tubular flow path 21P are drawn larger for the sake of explanation, but actually, a large number of grooves 21U (tubular flow paths 21P) each of which is smaller than 1 mm are formed.

  As described above, the method in which the groove 21U is formed on the upper surface of the heater 21 and the flow path is formed by overlapping with the lower surface 22S of the heat insulating block 22 is capable of cooling the heater 21 from the inside. This is an advantageous cooling method.

JP-A-10-340915 JP 2014-22629 A

  In FIG. 10, the groove 21U is not formed near the center of the heater 21. This is because the electronic component C is sucked and held near the center of the attachment tool. That is, as shown in FIG. 8, it is necessary to form a decompression flow path 2V near the center of the attachment tool 20 for holding the electronic component C by suction. The block 22 is provided with a hole 21VC (FIG. 10) and a hole 22VC (FIG. 11). For this reason, the groove 21U communicating with the outside and the hole 21VC which needs to maintain the reduced pressure state cannot be provided at the same position, and the groove 21U cannot be provided near the center of the heater 21 where the hole 21VC exists. In FIG. 10 (FIG. 11), the holes 21VA (holes 22VA) are provided separately from the holes 21VC (holes 22VC), but the holes 21VA (holes 22VA) form a decompression flow path by a method of holding the attachment tool 20 by suction. The groove 21U cannot be provided at the position of the hole 21VA, as in the case of the hole 21VC. Since the attachment tool 20 needs to be replaced with an optimal one according to the shape of the electronic component C, a method of sucking and holding the attachment tool 20 is often used to facilitate replacement.

  As described above, the heater 21 shown in FIG. 10 has the region 21F where the groove 21U is not formed. When the heater 21 is used, cooling can be performed from the inside, but the cooling air cannot be sent to the region 21F. Further, as shown in FIG. 12, since the region 21F is in surface contact with the heat insulating member 22, the heat HT cannot be conducted to the upper portion and is hardly cooled. Also, even if the heat HT reaches the groove 21U even if the heat is transmitted in the horizontal direction (left-right direction) in FIG. 12, the heat radiation amount is small (because the heat transfer of air is smaller than the heat transfer of the heater member). Hard to do. Here, since the decompression flow path 2V is formed in the area 21F, the temperature around the decompression flow path 2V is less likely to decrease than in other parts. That is, when the heater 21 is cooled, the cooling efficiency of the electronic component C immediately below the decompression flow path 2V is not good.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a bonding head that reduces cooling unevenness due to a heater position and efficiently cools an electronic component sucked and held by the bonding head when cooling the heater of the bonding head. And a mounting device using the same.

In order to solve the above problems, the invention described in claim 1 is
A bonding head used for heat compression bonding of electronic components,
An attachment tool that holds the electronic components on the underside,
Arranged on the upper part of the attachment tool, in a plate shape, a hole forming a decompression flow path penetrating both sides was formed, and a plurality of grooves for flowing cooling air were formed in a region not overlapping with the hole on the upper surface . A heater,
A plate-like heat transfer member disposed above the heater,
And a heat insulating block disposed above the heat transfer member.

The invention according to claim 2 is the bonding head according to claim 1,
The thermal conductivity of the heat transfer member is equal to or higher than the thermal conductivity of the heater.

  According to a third aspect of the present invention, there is provided a mounting apparatus including the bonding head according to the first or second aspect.

  ADVANTAGE OF THE INVENTION By the bonding head of this invention and the mounting apparatus using the same, when cooling the heater of a bonding head, it becomes possible to reduce the cooling unevenness by the heater position, and to cool the electronic component which the bonding head adsorbs and holds efficiently.

FIG. 2 is a diagram showing a bonding head according to one embodiment of the present invention. FIG. 3 is a diagram illustrating a heater, a heat transfer member, and a heat insulating block of the bonding head according to one embodiment of the present invention. It is a three-view figure showing the structure of the heat insulation member used for the bonding head concerning another embodiment of the present invention. FIG. 7 is a diagram illustrating a heat transfer state near the center of a heater of a bonding head according to another embodiment of the present invention. FIG. 9 is a view showing a heater, a heat transfer member, and a heat insulating block of a bonding head according to another embodiment of the present invention. It is a three-view figure showing the structure of the heat insulation block used for the bonding head concerning another embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of a mounting device. FIG. 3 is a diagram illustrating a configuration of a bonding head. FIG. 4 is a diagram illustrating a heater and a heat insulating block of a bonding head according to a known technique. It is a three-view figure showing the structure of the heater of the bonding head of a well-known art. It is a three-view figure showing the structure of the heat insulation block of the bonding head of a well-known art. FIG. 3 is a diagram illustrating a heat transfer state near the center of a heater of a bonding head according to a known technique.

An embodiment of the present invention will be described with reference to the drawings.
In one embodiment of the present invention, in the mounting apparatus 1 shown in FIG. 7, the bonding head 2 has the configuration shown in FIG. The bonding head 2 of FIG. 1 includes a heat transfer member 25 between the heater 21 and the heat insulating block 22 unlike the known technique of FIG. FIG. 2 shows the relationship between the heater 21, the heat insulating block 25 and the heat transfer member in the bonding head 2. The three views of the heater 21 and the heat insulating block 22 shown in FIG. 2 are as shown in FIGS. 10 and 11, and the three views of the heat transfer member 25 are shown in FIG.

  The heater 21 has a heating resistor embedded therein, and is made of a ceramic material. As the ceramic material, a material having high thermal conductivity (50 W / m · K or more) and excellent electrical insulation is desirable. Aluminum is preferred. The structure is as shown in a three-sided view in FIG. 10, and a plurality of grooves 21U having a width of WU and a depth of HU are formed from one side of the upper surface to the opposite side. By forming a plurality of grooves 21U, a plurality of comb-shaped walls 21W are formed. In the heater 21 shown in FIG. 10, the upper portion 21T of the wall 21W has the same height as the upper surface 21S of the heater 21, and the height of the wall 21W is HU. The width of the wall 21W is WT, but the width WT is determined by the width WU of the groove 21U and the formation pitch. The holes 21VC are provided for forming a decompression flow path 2V for adsorbing and holding the semiconductor C, and the holes 21VA are provided for forming a decompression flow path for adsorbing and holding the attachment tool 20. It was done.

  The heat insulating block 22 prevents heat generated by the heater 21 from being transmitted in directions other than the attachment tool 20. Ceramics are used in consideration of heat resistance and mechanical strength, but the heat conductivity is 5 W / m. K or less, desirably 1.5 W / m · K or less. The structure is as shown in a three-sided view in FIG. 11, in which a depression 22D is formed in a range over all the grooves 21U of the heater 21, and a ventilation hole 22V connected to the depression 22D is provided. The holes 22VC are provided for forming a decompression flow path 2V for holding the electronic component C by suction, and the holes 22VA are provided for forming a decompression flow path for holding the attachment tool 20 by suction. It is a thing.

  The heat transfer member 25 is provided to transfer the heat of the region 21F shown in FIG. 2 to the low temperature side when cooling the heater 21, and is formed of a material having a heat conductivity of 50 W / m · K or more. It is preferable to use a material having a thermal conductivity equal to or higher than that of the heater 21. As a specific material, metals having heat conductivity and heat resistance, such as metals such as silver, copper, and tungsten, and ceramics such as aluminum nitride and silicon carbide can be used.

  When a metal is used as the material of the heat transfer member 25, it is necessary to pay attention to the metal fine powder which affects the mounting quality when mounting the electronic component. However, since the metal has extensibility, the upper surface 25A of the heat transfer member 25 is in close contact with the lower surface 22S of the heat insulating block 22 by being sandwiched between the heater 21 and the heat insulating block 22 which are both ceramics, and the metal is conductive. Since the lower surface 25A of the heat member 25 is in close contact with the upper surface 21S of the heat insulating block 22, it is useful for ensuring the tightness of the decompression channel.

  When ceramic is used as the material of the heat transfer member 25, friction and distortion between the materials due to expansion can be suppressed as long as the material has a coefficient of linear expansion substantially equal to that of the heater 21. In addition, it is also possible to fix and bond and bake into an integral type, and it is advantageous to secure the hermeticity of the decompression flow path further by using the integral type.

  The structure of the heat transfer member 25 is as shown in the three views in FIG. 3. The heat transfer member 25 is provided with an opening 25 </ b> H communicating with the depression 22 </ b> D provided in the heat insulating block 22. A hole 25VC for forming the flow path 2V and a hole 25VA for forming a decompression flow path for holding the attachment tool 20 by suction are provided.

  If the thickness T of the heat transfer member 25 is too large, heat dissipation becomes large, which has an adverse effect when the temperature of the heater 21 rises. Therefore, it is necessary to select an appropriate thickness, and determine an appropriate value in consideration of thermal conductivity and the like. There is a need. However, even if the heating time is increased due to a decrease in efficiency when the heater 21 is heated, if the effect of shortening the cooling time is great, the thickness may be selected by giving priority to the effect of shortening the tact time. Specifically, the appropriate value of the thickness T of the heat transfer member 25 exists between 0.05 mm and 1.0 mm.

  By providing the heat transfer member 25 between the heater 21 and the heat insulating block 22, the heat HT in the region 21F of the heater 21 is transmitted to the upper heat transfer member 25 and the heat transmitted to the heat transfer member 25 as shown in FIG. The HT travels laterally (the temperature is reduced by air cooling). Therefore, the cooling performance of the region 21F of the heater 21 is greatly improved as compared with the case where the heater 21 and the heat insulating member 22 are closely adhered. That is, when the heater 21 of the bonding head 2 is cooled, uneven cooling due to the in-plane position of the heater 21 is reduced.

  For this reason, when the solder of the electronic component C sucked and held by the bonding head 2 is cooled to a solid state, the solder in the surface of the electronic component C solidifies uniformly, so that the solder height is stable and good connection is achieved. Can be obtained.

  Note that there is a configuration shown in FIG. 5 as another embodiment of the present invention. In FIG. 5, the structure of the heat insulating block 22 is as shown in FIG. 6, and does not have the depression 22D as shown in FIG. That is, the heat insulating block 22 having no depression 22D is superimposed on the opening 25H provided in the heat transfer member 25 shown in FIG. 3, and the opening 25H and the lower surface 22S of the heat insulating block 22 in FIG. It functions similarly to the depression 22D. With this configuration, it is possible to save the trouble of opening the recess 22D when manufacturing the heat insulating block 22.

  Further, the present invention may be applied not only to the bonding head 2 but also to the substrate stage 4 for holding and heating the substrate B side, and it may be used for both the bonding head 2 and the substrate stage 4 to perform heating and cooling from both sides. good. When the electronic component C is minute and the substrate B side has a large volume and the amount of heat from the head side is not sufficiently transmitted, it is effective to heat the substrate B side with a heater. In this case, it is effective to heat the heater from both sides.

DESCRIPTION OF SYMBOLS 1 Mounting device 2 Bonding head 2V Decompression flow path 3 Bonding unit 4 Substrate stage 5 Image recognition means 20 Attachment tool 21 Heater 21P Tubular flow path 21S Upper surface of heater 21T Upper part of wall 21U Groove 21W Wall forming groove 22 Insulating block 22D recess 22S Lower surface of heat insulating block 22V Vent hole 23 Holder 24 Head body 25 Heat transfer member 25A Upper surface of heat transfer member (heat insulating block side)
25B Lower surface of heat transfer member (heater side)
B Board C Electronic component HU Groove depth WT Wall width (thickness)
WU groove width

Claims (3)

A bonding head used for heat compression bonding of electronic components,
An attachment tool that holds the electronic components on the underside,
Arranged on the upper part of the attachment tool, in a plate shape, a hole forming a decompression flow path penetrating both sides was formed, and a plurality of grooves for flowing cooling air were formed in a region not overlapping with the hole on the upper surface . A heater,
A plate-like heat transfer member disposed above the heater,
A bonding head comprising: a heat insulating block disposed above the heat transfer member. The bonding head according to claim 1, wherein
The thermal conductivity of the heat transfer member is higher than the thermal conductivity of the heater. A mounting apparatus comprising the bonding head according to claim 1.

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