Mounting head

Abstract

To provide a mounting head capable of quickly cooling an element holding surface. Specifically, a mounting head 4 includes an element holding surface 43a for holding an element C, a heat tool 42 for heating the element holding surface 43a, and a spray part 7 for spraying a liquid toward the heat tool 42, and mounts the element C held by the element holding surface 43 on a substrate W by thermocompression bonding. The spray part 7 sprays the liquid to the heat tool 42 after completion of mounting of one element C and before mounting of the subsequent element C.

Description

Mounting Head

[0001] The present invention relates to a mounting head in a mounting apparatus that mounts chip components at predetermined positions on a substrate.

[0002] Bonding is an essential step in the mounting of electronic components and the manufacturing process of semiconductor devices, and is used for joining a plurality of components on a substrate.

[0003] FIG. 4 shows a mounting apparatus that performs this bonding process. In the mounting apparatus 101, a mounting head 104 is provided above a substrate stage 102, and in a state where a chip component C conveyed by a chip conveying means 106 is held on the lower surface of the mounting head 104, an elevating unit 103 lowers the mounting head 104, thereby pressing the chip component C against a predetermined position of a substrate W placed on the substrate stage 102. Then, as the temperature of the substrate stage 102 and the mounting head 104 increases, the chip component C is thermocompression-bonded to the substrate W, and the chip component C is mounted on the substrate W. During bonding, it is important to appropriately heat the substrate and components, and a heat tool is usually used.

[0004] FIG. 5 is a detailed view of the mounting head 104. At the distal end of the mounting head 104, there is an attachment tool 143 that suction-holds the chip component C, and a heat tool 142 is provided so as to be in contact with the attachment tool 143. When mounting the chip component C onto the substrate W, the heat tool becomes high temperature and heats the chip component C via the attachment tool 143. As a result, bumps provided on the chip component melt, and the chip component C and the substrate W are joined to each other.

[0005] The upper part of the heat tool 142 is provided with a chamber portion 141 that covers the upper surface of the heat tool 142, with a cavity portion 144 provided therein. A gas supply path 145 passes through the cavity portion 144 formed by the chamber portion 141 and the heat tool 142 from the outside of the mounting head 104, and the openings 145a to 145c, which are the open ends of this gas supply path 145, are directed toward the heat tool 142. After the mounting of one chip component C is completed, and before mounting the next chip component C, gas is supplied from the gas supply path 145 as shown in Figure 6, and this gas is released from the openings 145a to 145c and hits the heat tool 142, thereby cooling the hot heat tool 142 and also cooling the attachment tool 143.

[0006] In the conventional mounting apparatus 101, there was a limit to the flow rate of gas supplied through the gas supply path 145, which caused the cooling rate of the heat tool 142 and attachment tool 143 to plateau. As a result, it was sometimes necessary to wait for the heat tool 142 and attachment tool 143 to cool completely before adsorbing and holding the next chip component C, which could affect the bonding cycle time.

[0007] In view of the above problems, the present invention aims to provide a mounting head that can rapidly cool the element holding surface.

[0008] To solve the above problems, the mounting head of the present invention comprises an element holding surface for holding elements, a heat tool for heating the element holding surface, and a spray unit for spraying liquid toward the heat tool. The mounting head mounts elements held by the element holding surface onto a substrate by thermocompression bonding, and is characterized in that, after the mounting of one element is completed, and before mounting the next element, the spray unit sprays liquid toward the heat tool.

[0009] In the mounting head of the present invention, the heat tool is cooled by the heat of vaporization when the sprayed liquid comes into contact with it. This allows the heat tool and the element holding surface to be cooled at a higher cooling rate than air cooling. Furthermore, by vaporizing the mist-like liquid by applying it to the heat tool, no liquid remains on the heat tool after cooling is complete, and does not interfere with the heating of the heat tool during the next mounting.

[0010] Furthermore, the heat tool may further include a chamber surrounding the surface on which the liquid is sprayed, and a depressurization means for reducing the pressure in the space within the chamber, wherein the space within the chamber is depressurized by the depressurization means when the liquid is sprayed.

[0011] By doing so, the vaporization temperature of the liquid can be lowered, allowing the heat tool to be cooled by spraying to even lower temperatures.

[0012] Furthermore, in the spraying section, it is preferable that the liquid supply path that supplies the liquid toward the heat tool and the gas supply path that supplies the gas for atomizing the liquid merge near the heat tool.

[0013] This improves cooling efficiency because the sprayed liquid comes into more efficient and stable contact with the heat tool.

[0014] The mounting head of the present invention enables rapid cooling of the element holding surface.

[0015] This is a perspective view showing the schematic configuration of a mounting apparatus equipped with the mounting head of the present invention. This is a detailed view of the mounting head of the present invention. This is a diagram showing how the heat tool and element holding surface are cooled in the mounting head of the present invention. This is a perspective view showing the schematic configuration of a conventional mounting apparatus. This is a detailed view of a conventional mounting head. This is a diagram showing how the heat tool and element holding surface are cooled in a conventional mounting head.

[0016] The mounting head of the present invention will be described below with reference to the drawings.

[0017] Figure 1 is a perspective view showing a schematic configuration of a mounting device equipped with the mounting head of the present invention.

[0018] The mounting apparatus 1 shown in Figure 1 has a base on which a substrate stage 2 and a gantry frame are provided. The substrate stage 2 has the function of holding the substrate W and moving it in the direction in the substrate plane. The gantry frame fixes a lifting unit 3 above the substrate stage 2, and a mounting head 4 is connected to the vertical drive shaft of the lifting unit 3. The mounting apparatus 1 also consists of a chip transport means 6 for transporting chip components C to the mounting head 4, and an alignment camera 5 for acquiring positional information of the chip components C and the substrate when aligning them.

[0019] In this mounting apparatus 1, the chip component C held by the mounting head 4 is brought close to the substrate W on the substrate stage 2 and thermally pressed to mount the chip component C onto the substrate W.

[0020] Furthermore, the mounting head 4 is equipped with a spray unit 7, which will be described later, that sprays liquid toward a heat tool 42, which will be described later, and is a means for heating the chip component C.

[0021] Furthermore, these components of the mounting device 1 are enclosed by a cover portion 10 having a door portion 11.

[0022] The substrate stage 2 consists of a stage movement mechanism and a suction table. The suction table holds the substrate W placed on its surface by suction, and the suction table can be moved in the in-plane direction of the substrate W surface while holding the substrate W by the stage movement mechanism. The stage movement mechanism then sequentially moves the multiple mounting locations provided on the substrate W directly below the mounting head 4.

[0023] Furthermore, the suction table is equipped with a heating mechanism, which heats the substrate W to a predetermined temperature during the mounting operation of chip components C onto the substrate W placed on the suction table. Here, the chip components C are equipped with solder, and by heating the substrate W, the solder on the chip components C is also heated and softened from the substrate W side during the mounting operation.

[0024] The lifting unit 3 is fixed to a gantry frame, and its vertical drive shaft is positioned perpendicular to the suction table of the substrate stage 2. The mounting head 4 is connected to the vertical drive shaft. The lifting unit 3 has the function of driving the mounting head 4 up and down and applying a pressure according to the setting. In this embodiment, the lifting unit 3 is driven by a servo motor.

[0025] The mounting head 4 is connected to the lifting unit 3 and mounts the chip component C onto the substrate W by holding the chip component C and pressing it parallel to the substrate W (held on the suction table of the substrate stage 2). The mounting head 4 has a heat tool 42 and an attachment tool 43. The head body 40 has the heat tool 42 fixedly positioned on its lower side. The heat tool 42 has a heating function and heats the chip component C via the attachment tool 43. The heat tool 42 also has a function to hold the attachment tool 43 by suction using a reduced pressure channel (not shown). The attachment tool 43 has an element holding surface 43a and holds the chip component C by suction, and is replaced according to the shape of the chip component C.

[0026] The alignment camera 5 has a field of view in the vertical direction and, before mounting the chip component C, moves between the chip component C and the substrate W using a drive mechanism (not shown) to focus on and capture images of the alignment marks on the chip component C and the substrate W, thereby acquiring positional information of the alignment marks on the chip component C and the substrate W. Based on this positional information, the alignment of the chip component C and the substrate W is performed.

[0027] The chip transport means 6 consists of a transport rail and a chip slider. The chip slider holds the chip component C supplied from a chip supply unit (not shown) and slides it to directly below the attachment tool 43 for transport.

[0028] Here, a chip supply unit (not shown) places the chip component C at a fixed position on the chip slider. If necessary, the placement position of the chip component C on the chip slider may be recognized by an imaging means (not shown). By controlling the position of the chip slider and the chip component C placed on the chip slider in this way, it is possible to transfer the chip component C within a predetermined range of the attachment tool 43, and after the attachment tool 43 has held the chip component C, the chip slider, having released the chip component C, moves to a retracted position.

[0029] The operation of the substrate stage 2, lifting unit 3, mounting head 4, alignment camera 5, and chip transport means 6 is controlled by a control unit (not shown).

[0030] Figure 2 is a detailed view of the mounting head 4.

[0031] As described above, the mounting head 4 has a heat tool 42 and an attachment tool 43. When the chip component C is held in place by suction on the element holding surface 43a of the attachment tool 43, the heat tool 42 generates heat, and the chip component C is heated via the attachment tool 43.

[0032] A chamber portion 41 is provided on the upper side of the heat tool 42. The chamber portion 41 has a recess formed by four side walls facing the heat tool 42, and the lower end surfaces of these side walls come into contact with the heat tool 42, so that the recess of the chamber portion 41 surrounds the upper surface of the heat tool 42, and this recess becomes a sealed space. In this description, this sealed space is referred to as the depressurization chamber 44. A depressurization means 45 consisting of a vacuum pump is connected to this depressurization chamber 44, and the inside of the depressurization chamber 44 is depressurized when the depressurization means 45 is operated by a control means (not shown).

[0033] Furthermore, the mounting head 4 has a spray unit 7 that sprays a spray-like (mist-like) liquid onto the heat tool 42.

[0034] The spray unit 7 has a gas supply path 71 for supplying gas and a liquid supply path 72 for supplying liquid. Gas is supplied to the gas supply path 71 from a gas supply source (not shown), and liquid is supplied to the liquid supply path 72 from a liquid supply source (not shown). In this embodiment, the gas passing through the gas supply path 71 is compressed air, and the liquid passing through the liquid supply path 72 is water. Control valves (not shown) are provided in the gas supply path 71 and the liquid supply path 72 to adjust the supply amounts of gas and liquid.

[0035] The gas supply path 71 and the liquid supply path 72 penetrate the chamber section 41 and are routed from outside the chamber section 41 to the depressurization chamber 44. In the configuration shown in Figure 2, the gas supply path 71 branches into three branch paths 71a, 71b, and 71c inside the depressurization chamber 44. The openings 71d, 71e, and 71f, which are the ends of these branch paths 71a to 71c, are located slightly apart from the upper surface of the heat tool 42.

[0036] The liquid supply path 72, like the gas supply path 71, branches within the depressurization chamber 44. In this embodiment, the liquid supply path 72 branches into branch paths 72a, 72b, and 72c, and these branch paths 72a to 72c communicate with each other near the openings 71d to 71f.

[0037] In this spray unit 7, when gas is supplied from the gas supply path 71 and a small amount of liquid is supplied from the liquid supply path 72, the liquid that merges into the branch paths 71a to 71c from the connecting section of the branch paths 72a to 72c and the branch paths 71a to 71c is sprayed out from the openings 71d to 71f. Here, since there are multiple outlets of the gas supply path 71 facing the heat tool 42, such as the openings 71d to 71f, the sprayed liquid can be applied to a wide area of ​​the upper surface of the heat tool 42.

[0038] Next, Figure 3 shows how the heat tool 42 and the element holding surface 43a are cooled in the mounting head 4 of the present invention.

[0039] When mounting multiple chip components C onto a substrate W, after the mounting of one chip component C onto the substrate W is complete and the element holding surface 43a separates from the chip component C, the next chip component C is transported to the element holding surface 43a by the chip transport means 6 described above, and the element holding surface 43a attracts and holds the chip component C in preparation for the next mounting.

[0040] Here, if the element holding surface 43a remains at a high temperature, there is a risk that the solder applied to the chip component C may melt before the chip component C is brought into close contact with the substrate W. Therefore, the element holding surface 43a must be sufficiently cooled before it can adsorb and hold the chip component C. Since the time required for this cooling directly affects the cycle time of chip mounting, it is preferable that this cooling time be as short as possible.

[0041] In the mounting head 4 of the present invention, after the mounting of the chip component C is completed and the element holding surface 43a is separated from the chip component C, and after the operation of the heating element of the heat tool 42 is turned off, the supply of gas from the gas supply path 71 and the supply of liquid from the liquid supply path 72 are started, and the spray S is sprayed toward the heat tool 42.

[0042] When the spray S hits the heat tool 42, the high temperature of the heat tool 42 vaporizes the liquid forming the spray S. The heat of vaporization at this time cools the heat tool 42. By utilizing the heat of vaporization in this way, cooling can be performed at a faster rate compared to conventional air cooling of the heat tool. As the heat tool 42 cools and its temperature decreases, the temperature of the element holding surface 43a of the attachment tool 43 also decreases.

[0043] Furthermore, as described above, the liquid supply path 72 branches into branch paths 72a, 72b, and 72c, and these branch paths 72a to 72c communicate with branch paths 71a to 71c, respectively, near the openings 71d to 71f. This allows the sprayed liquid to come into contact with the heat tool more efficiently and stably, thereby improving cooling efficiency.

[0044] Also, at this time, the pressure reducing means 45 is in operation, and the gas in the decompression chamber 44 containing vaporized liquid is discharged out of the decompression chamber 44 by the pressure reducing means 45. This pressure reducing means 45 may operate according to the cooling timing of the heat tool 42, or may operate continuously from the start to the completion of mounting of the plurality of chip components C. Further, a cold trap or the like may be provided on a pipe connecting the decompression chamber 44 and the pressure reducing means 45 to condense and recover the liquid.

[0045] By cooling the heat tool 42 using heat of vaporization as described above and discharging the vaporized liquid out of the decompression chamber 44 by the pressure reducing means 45, it is possible to prevent the sprayed liquid from remaining on the heat tool 42 and in the decompression chamber 44. Here, if the heat tool 42 is cooled by water cooling, there is a risk that the cooling liquid remains on the heat tool 42 even after the cooling of the heat tool 42 is completed. If the cooling liquid remains as described above, it becomes an obstacle when the temperature of the heat tool 42 is increased for mounting the next chip component C, which delays the heating of the chip component C. In contrast, in the mounting head 4 of the present embodiment, since the sprayed liquid does not remain on the heat tool 42 and in the decompression chamber 44 as described above, it does not interfere with the mounting of the next chip component C.

[0046] On the other hand, even with the mounting head 4 of the present embodiment, after the heat tool 42 is cooled to a predetermined temperature, the heat tool 42 can no longer sufficiently vaporize the spray S. Therefore, in order to prevent the incompletely vaporized liquid from remaining on the heat tool 42, it is necessary to stop the supply of the liquid from the liquid supply path 72. For this reason, when it is necessary to further cool the heat tool 42, the supply of gas from the gas supply path 71 may be continued for a predetermined time after the supply of the liquid is stopped, and the heat tool 42 may be further cooled by air cooling.

[0047] Further, if the pressure inside the decompression chamber 44 is reduced by the decompression means 45, the vaporization temperature of the liquid generally becomes lower. Accordingly, if the pressure inside the decompression chamber 44 is reduced, the lower limit of the temperature of the heat tool 42 at which spraying of the spray S can be continued can be further lowered, so that the heat tool 42 can be cooled efficiently. Therefore, it is preferable that the pressure inside the decompression chamber 44 during cooling of the heat tool 42 is low, and it is preferable to maintain the pressure at least equal to atmospheric pressure.

[0048] The mounting head described above enables rapid cooling of the element holding surface.

[0049] Here, the mounting head of the present invention is not limited to the embodiment described above, and may have other forms within the scope of the present invention. For example, in the above description, the gas passing through the gas supply path 71 is compressed air, and the liquid passing through the liquid supply path 72 is water, but this is not mandatory. For example, the gas passing through the gas supply path 71 may be nitrogen or the like. Further, the liquid passing through the liquid supply path 72 may be, for example, ethanol or the like. Alternatively, a plurality of types of liquids having different vaporization temperatures may be used, and the liquid to be sprayed may be switched according to the temperature of the heat tool 42.

[0050] Further, in the above description, the gas inside the decompression chamber 44 containing vaporized liquid is discharged to the outside of the decompression chamber 44 by the decompression means 45. However, the present invention is not limited to this. No decompression means may be provided, and only a through hole may be provided in a side wall of the chamber portion similar to that in FIG. 6, so that the gas containing the vaporized liquid inside the chamber portion is discharged according to the pressure difference between the inside and outside of the chamber portion.

[0051] 1 Mounting device 2 Substrate stage 3 Lifting unit 4 Mounting head 5 Alignment camera 6 Chip transport means 7 Spray section 10 Cover section 11 Door section 41 Chamber section 42 Heat tool 43 Attachment tool 43a Element holding surface 44 Pressure chamber 45 Pressure reducing means 71 Gas supply path 71a Branch path 71b Branch path 71c Branch path 71d Opening 71e Opening 71f Opening 72 Liquid supply path 72a Branch path 72b Branch path 72c Branch path 101 Mounting device 102 Substrate stage 103 Lifting unit 104 Mounting head 106 Chip transport means 141 Chamber section 142 Heat tool 143 Attachment tool 144 Cavity section 145 Gas supply path 145a Opening 145b Opening 145c Opening C Chip component S Spray W Substrate

Claims

1. A mounting head comprising: an element holding surface for holding elements; a heat tool for heating the element holding surface; and a spray unit for spraying liquid toward the heat tool, wherein the element held by the element holding surface is mounted onto a substrate by thermocompression bonding, characterized in that after the mounting of one element is completed, and before mounting the next element, the spray unit sprays liquid toward the heat tool.

2. The mounting head according to claim 1, further comprising a chamber portion surrounding the surface of the heat tool on which the liquid is sprayed, and a depressurization means for depressurizing the space within the chamber portion, wherein the space within the chamber portion is depressurized by the depressurization means when the liquid is sprayed.

3. The mounting head according to claim 1, characterized in that, in the spraying section, a liquid supply path for supplying the liquid toward the heat tool and a gas supply path for supplying gas to atomize the liquid merge near the heat tool.

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