JP2005159231A - Flip-chip bonding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient and inexpensive flip-chip bonding apparatus which can mount any size of semiconductor chip on a circuit board at a given mounting angle while eliminating the need for exchanging a mounting tool. <P>SOLUTION: The apparatus comprises a freely-movable bonding head main body 1, a heater 2 mounted to the bonding head main body 1, and a mounting tool 9 having a sucking through-hole and mounted on the lower surface of the heater 2. The mounting tool includes a flange 4 mounted on the lower surface of the heater 2, and a holder projected from the lower surface of the flange 4, having the sucking through-hole in its center and having a flat lower surface. The holder 5 has a plurality of concentric columar members 5a, 5b for accommodating a semiconductor chip 31 oriented in one direction on its lower surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flip chip bonding apparatus for mounting a semiconductor chip on a circuit board.

  Flip chip bonding technology capable of mechanically and electrically connecting a semiconductor chip and a circuit board has been attracting attention in the trend toward lighter, thinner and smaller devices in portable information terminal devices and the like.

  Moreover, in recent portable terminal devices, with the downsizing and high functionality of a single module, there are many cases where a large number of semiconductor chips including the same type and different types are mounted on the same circuit board. The flip chip bonding apparatus capable of thinly mounting such a semiconductor chip directly on a circuit board is rapidly spreading.

  FIG. 6 shows a bonding head 10 portion of a general flip chip bonding apparatus. A movable bonding head main body 1, a heater section 2 attached to the bonding head main body 1, and a lower surface of the heater section 2 are shown. And a mounting tool 3 attached thereto.

The mounting tool 3 has a flange portion 4 detachably attached to the lower surface of the heater 2 by suction means or mechanical means. As shown in FIG. 8, the semiconductor chip 31 ( A holding portion 5 for holding a flip chip) is integrally formed.
A through hole 6 (not shown) connected to the vacuum pipe path of the flip chip bonding apparatus (not shown) is provided in the approximate center of the holding part 5, and the semiconductor chip 31 is held in the holding part 5 by vacuuming from the through hole 6 during mounting. It is attracted and held on the lower surface of the plate.

  The semiconductor chip 31 attracted and held by the holding part 5 of the flange part 4 is mounted on the circuit board 30 by the face-down method while being heated by the upper heater part 2. That is, in the face-down method, the heated semiconductor chip 31 is pressed against the circuit board 30 by the lowering operation of the bonding head body 1 as shown in FIG. At the same time, the bonding pad 33 provided on the circuit board 30 is fixed, and the semiconductor chip 31 is connected to the bonding pad 33 on the board through the electrode 32.

As a prior art of the flip chip bonding apparatus, Patent Document 1 is disclosed. Patent Document 1 discloses a flip chip bonding apparatus in which three types of units capable of attracting and holding a semiconductor chip in a predetermined direction are provided, and a plurality of semiconductor chips having different sizes are mounted on a circuit board.
JP-A-6-140470

  By the way, conventionally, in order to increase the suction / holding force in the holding part 5, as shown in FIG. 8, a countersink 7 having a constant depth corresponding to the longitudinal direction of the semiconductor chip 31 is formed on the lower surface of the holding part 5. In some cases, the holding part 5 is processed into a rectangular shape in accordance with the size and mounting direction of the semiconductor chip 31 in order to apply an optimal temperature and load for connection to the circuit board 30 to the semiconductor chip 31 during mounting. Is used.

  For this reason, when mounting a plurality of semiconductor chips 31 of the same size, particularly rectangular semiconductor chips 31, with the mounting direction being different from each other in the horizontal direction and the vertical direction with respect to the circuit board, in the conventional structure, FIG. It is necessary to prepare two types of mounting tools 3 shown in (b) and replace them according to the mounting direction.

This is due to the following reason.
That is, in the module production process, when a plurality of semiconductor chips 31 of the same size are mounted on the same circuit board 30, and when the mounting direction is limited to one direction, FIG. The vertical mounting tool shown in FIG. 9 and the horizontal mounting tool shown in FIG. 9C may be properly used. However, in the production of a module in which vertical mounting and horizontal mounting chips are mixed on the same circuit board, for example, for vertical mounting. When mounting using a tool, a vertical mounting chip is good, but for a horizontal mounting chip, as shown in FIG. 9B, the holding unit 5 holds only a part of the semiconductor chip 31, for example, Even if the flip chip bonding apparatus is set to an optimum mounting condition, a sufficient temperature and load necessary for connection to the circuit board 30 cannot be applied. There occur. In addition, there is a risk that an excessive pressing force is applied to the semiconductor chip 31 during mounting, and the chip is damaged.

  Further, when the above-described counterbore 7 is formed in the holding portion 5 of the mounting tool 3, air enters from the counterbore 7, making it difficult to attract and hold the semiconductor chip 31.

  In addition, since the mounting tool 3 is often made of a ceramic-based material, in a flip chip bonding apparatus of a type in which the mounting tool 3 is manually replaced, an operator must drop the mounting tool 3 when replacing the tool. There was an accident that caused damage. In particular, precision processing using special ceramics such as aluminum nitride, silicon nitride, and silicon carbide as ceramic materials requires a lot of time to manufacture the mounting tool 3 and the manufacturing cost is high. Making them individually according to the direction or replacing them after being damaged led to an increase in the cost of the module.

  Further, when the flange portion 4 has a square shape such as a non-directional shape, there is a high risk that the mounting direction may be exceeded when the tool is replaced. Therefore, as shown in FIG. 6, the operator can check the mounting direction on the flange portion 4. It was necessary to provide some mark 8. This also complicates the structure of the mounting tool 3 and increases costs.

  Moreover, since the replacement work of the mounting tool 3 is normally performed in a state where the operation of the flip chip bonding apparatus is stopped, the efficiency of the mounting work is greatly reduced due to a time loss due to the replacement work. Even in the flip chip bonding apparatus that can automatically replace the mounting tool 3, it takes about 4 to 10 seconds to replace the mounting tool 3, which inevitably leads to an increase in man-hours.

  The present invention has been made in view of such conventional problems, and it is possible to continuously mount a semiconductor chip of any size on a circuit board at an arbitrary mounting angle without exchanging a mounting tool. An object of the present invention is to provide a flip chip bonding apparatus that is inexpensive and inexpensive.

  That is, the present invention according to claim 1 has a movable bonding head main body, a heater portion attached to the bonding head main body, and a suction through hole, and is attached to the lower surface of the heater portion. In a flip chip bonding apparatus that includes a mounting tool and mounts a semiconductor chip adsorbed and held on the mounting tool on the circuit board while being heated by the heater unit, the mounting tool is attached to the lower surface of the heater unit. And a flat bottom holding portion that is provided on the bottom surface of the flange portion and has a through-hole for suction at the center, and the semiconductor chip is placed in one direction on the bottom surface of the holding portion. It is characterized in that a plurality of columnar members are arranged concentrically.

  In this configuration, when multiple semiconductor chips with the same dimensions are mounted on the circuit board, including the horizontal and vertical directions, there is no need to replace the mounting tool according to the mounting direction as in the past, and continuous mounting is possible. Become. Thereby, the mounting process of the semiconductor chip is made efficient, and the productivity is greatly improved.

  According to a second aspect of the present invention, there is provided a movable bonding head main body, a heater portion attached to the bonding head main body, and a suction through hole, and attached to the lower surface of the heater portion. In a flip chip bonding apparatus that includes a mounting tool and mounts a semiconductor chip adsorbed and held on the mounting tool on the circuit board while being heated by the heater unit, the mounting tool is attached to the lower surface of the heater unit. And a flat bottom holding portion that is provided on the bottom surface of the flange portion and has a through-hole for suction in the center, and the holding portion fits the semiconductor chip in the bottom surface in all directions. It is characterized by comprising a columnar member or a prismatic member.

  In this configuration, when multiple semiconductor chips of the same size or different sizes are mounted on the circuit board at an arbitrary mounting angle, it is possible to perform continuous mounting without having to replace the mounting tool according to the chip size and mounting direction. . Thereby, the mounting process of the semiconductor chip is made efficient, and the productivity is greatly improved.

  As described above, according to the present invention, when a semiconductor chip is mounted on a circuit board, it is not necessary to replace the mounting tool for each size and mounting angle of the semiconductor chip, and continuous mounting is possible. Productivity can be greatly improved.

  In addition, since the frequency of replacing the mounting tool is extremely low, it has been possible to prevent accidents such as the operator dropping and damaging the mounting tool during frequent tool replacement. Even if the flange portion is formed of a square or the like having no directionality, there is no fear of causing a mounting tool mounting error due to carelessness of the operator as in the conventional case.

  Furthermore, while two or more types of mounting tools have been conventionally manufactured according to the chip mounting direction, since only one type of mounting tool is required, tool manufacturing costs can be greatly reduced, and costs can be reduced.

  Hereinafter, an embodiment of a face-down flip-chip bonding apparatus according to the present invention will be described with reference to FIGS.

Here, FIG. 1 shows the main configuration of the flip chip bonding apparatus of the present embodiment, FIG. 2 shows the structure of the mounting tool, FIGS. 3 and 4 show the usage of the mounting tool shown in FIG. Reference numeral 5 denotes a module manufacturing process using the bonding apparatus of the present invention.
In addition, in order to simplify description, the same code | symbol was used about the member common in the past in the following description.

  As shown in FIG. 1, a bonding head 10 of this embodiment includes a movable bonding head main body 1, a heater part 2 attached to the bonding head main body 1, and a mounting tool 3 attached to the lower surface of the heater part 2. This point is the same as the conventional bonding head 10 shown in FIG. However, in this embodiment, the structure of the mounting tool 3 is different from the conventional type.

Hereinafter, the structure of the mounting tool 3 will be described.
FIG. 2 (a) shows a first embodiment of the mounting tool 3. As shown in the drawing, a rectangular column member having a flat bottom surface of a size that can accommodate a semiconductor chip (flip chip) is placed on the bottom surface of the flange portion 4 in a vertical and horizontal manner. The holding portion 5 is formed by arranging in a cross shape and providing a through-hole 6 for suction opening at the center of the crossing portion. The other end of the through hole 6 is connected to a vacuum pipe path of a flip chip bonding apparatus (not shown) so that the semiconductor chip is attracted and held on the lower surface of the holding portion 5 by evacuation from the through hole 6. It has become.

  FIG. 3 shows a usage pattern of the mounting tool 3 shown in FIG. In this mode of use, in FIG. 3A, the rectangular semiconductor chip 31 is sucked and held by the holding unit 5a in the vertical direction and mounted in the vertical direction with respect to the circuit board 30. Next, FIG. ), The semiconductor chip 31 having the same size is sucked and held by the horizontal holding portion 5b and mounted on the circuit board 30 in the horizontal direction.

  As described above, in this mounting tool 3, the rectangular semiconductor chip 31 that is entirely contained in the above-described cross-shaped prismatic member can be reliably sucked and held in either the horizontal direction or the vertical direction with respect to the circuit board 30. Moreover, the temperature and load necessary for connection to the circuit board 30 can be sufficiently applied by one mounting tool 3 in both cases of horizontal mounting and vertical mounting. Accordingly, in the production process of a module in which a plurality of semiconductor chips 1 having the same dimensions are mounted in the horizontal direction and the vertical direction with respect to the circuit board 30, the work of replacing the mounting tool 3 is completely unnecessary. Of course, there is no restriction on the mounting order of the vertical mounting and the horizontal mounting, and the mounting can be performed in an arbitrary order.

  In the mounting tool 3 of the first embodiment, the shape of the holding portion 5 is a cross shape as shown in FIG. 2A. However, a plurality of prismatic members in which the semiconductor chip 31 is accommodated may be arranged concentrically. Of course, this is also possible, and in this case, not only horizontal mounting and vertical mounting but also other diagonal mounting is possible.

  Next, FIG. 2B shows a second embodiment of the mounting tool 3. As shown in the drawing, a flat cylindrical member having a flat bottom surface is disposed on the bottom surface of the flange portion 4 so that the semiconductor chip can be accommodated. The holding portion 5 is formed by providing a through-hole 6 for suction opening at the center of the cylindrical member.

  In this way, by making the shape of the holding portion 5 into a circular shape on the upper surface, the semiconductor chip is not limited to the same size as long as it is a semiconductor chip of a size that fits within this circumference. The mounting tool 3 can sufficiently apply the temperature and load necessary for connection to the circuit board 30 and can be reliably attracted and held not only in the horizontal direction but also at an arbitrary angle.

  FIG. 4 shows a usage pattern of the mounting tool 3 shown in FIG. In this usage pattern, three types of semiconductor chips 31a, 31b, and 31c having different sizes are vertically mounted in FIG. 4A, horizontally mounted in FIG. 4B, and obliquely mounted in FIG. 4C. The mounting tool 3 is continuously mounted in three directions on the circuit board 30 by using one mounting tool 3 without replacing the mounting tool 3 for each mounting angle. Of course, the mounting order in each direction can be determined arbitrarily.

  In the mounting tool 3 of the second embodiment, the shape of the holding portion 5 is a columnar shape as shown in FIG. 2B, but may be a polygonal column shape of a size in which the semiconductor chip 31 can be accommodated. In any case, if the semiconductor chip 31 has a size that can be accommodated in all directions on the lower surface of the holding portion 5, it can be mounted at any continuous mounting angle.

  As described above, when mounting the semiconductor chip 31 on the circuit board 30, the mounting tool 3 of the present invention does not need to be replaced with the dedicated mounting tool 3 every time depending on the chip size and mounting angle. Since the mounting can be performed, the conventional tool replacement work in the module production process can be omitted, and the productivity is greatly improved.

  In addition, since the frequency of replacing the mounting tool 3 is extremely low, it is possible to prevent accidents such as the operator dropping and damaging the mounting tool 3 when the mounting tool 3 is frequently replaced. Even if the flange portion is formed of a square or the like having no direction for mounting the mounting tool 3, there is no fear of causing a mounting error of the mounting tool 3.

In order to confirm the effect of the mounting tool 3 of the present invention, the following man-hour calculation of the chip mounting process by the flip chip bonding apparatus was performed and the results are shown in Table 1.
The trial calculation target device is a device of the present invention that does not automatically exchange the mounting tool 3 with a conventional device that automatically performs the mounting tool replacement operation.
The conditions for the trial calculation are as follows (1) to (3).
(1) 8 modules / substrate.
(2) Two modules of the same size are mounted in the horizontal direction and the vertical direction per module.
(3) The mounting time includes a total of 3.0 sec including an operation cycle time of 2.0 sec of the flip chip bonding apparatus and a heating / pressurizing time of 1.0 sec.

  As is apparent from Table 1, the present invention achieves about 10% reduction in man-hours per module as compared with the conventional product. From this result, it was proved that the productivity is significantly improved by using the mounting tool 3 of the present invention.

Next, the production costs (design costs, respectively) of the conventional horizontal mounting tool and vertical mounting tool shown in FIGS. 8A and 8B and the mounting tool of the present invention shown in FIG. Production and processing costs) and production man-hours (production days) were estimated and compared. As a result, it was found that both the manufacturing cost and the manufacturing man-hour are less than half of the conventional product.
This is because the conventional product requires only one mounting tool compared to two mounting tools, and there is no need for the marking 8 processing of the flange portion 4 and the precise seating 7 processing of the holding portion 5 as in the conventional product. It is because it is.

  Next, a module production process using the flip chip bonding apparatus of the present invention will be described with reference to FIG.

  As shown in FIG. 5, this process includes a semiconductor chip mounting process (FIGS. 5A to 5C) using a flip chip bonding apparatus, and an epoxy resin coating process using a resin coating apparatus (FIG. 5D). The resin curing process using a thermostatic chamber (FIG. 5E) consists of three processes.

First, in FIG. 5A, the semiconductor chip 31 placed and accommodated on the tray 21 is taken out by the pickup unit 20. At this time, the electrode 32 (made of Au) of the semiconductor chip 31 faces upward.
Next, in FIG. 5B, the semiconductor chip 31 taken out by the pickup unit 20 is moved to a position directly below the bonding head 10 of the present invention, and the vertical position of the semiconductor chip 31 is inverted so that the electrode 32 faces downward. In this state, it is sucked and held by the mounting tool 3. The adsorption / holding of the semiconductor chip 31 is as described above.
Next, in FIG. 5C, the semiconductor chip 31 is heated to a temperature of about 400 to 450 ° C. by the heater unit 2 (ceramic heater) in a constant manner and is pressed against the circuit board 30, so that the electrodes of the semiconductor chip 31 are formed. A bonding pad (surface treatment Au plating) (not shown) of the circuit board 30 and the circuit board 30 is thermocompression bonded, and the semiconductor chip 31 is mechanically and electrically connected (solid phase diffusion bonding) on the circuit board 30. In the thermocompression bonding, the stage on which the circuit board 30 is placed is heated to about 150 ° C. This completes the mounting process of the semiconductor chip 31.

  Next, in FIG.5 (d), the liquid thermosetting resin (epoxy resin) with which the syringe 22 was filled is discharged from the needle 23, and it is from the side edge part of the semiconductor chip 31 mounted in the circuit board 30 at the front process. It is applied and filled in the gap between the circuit board 30 and the semiconductor chip 31. At this time, the substrate stage is heated to about 70 to 80 ° C. This completes the epoxy resin coating process.

  Finally, in FIG. 5E, the resin-encapsulated circuit board 30 mounted with a semiconductor chip is heated in a thermostatic chamber to cure the encapsulating resin. This completes the manufacture of the module.

  As described above, in the above production process, the NCP connection (Non Conductive Paste Connection) method, which has been one of the mainstreams in flip chip bonding, (that is, after a resin is applied on a circuit board and then a semiconductor chip is formed thereon) In this case, an Au-Au thermocompression bonding method in which resin sealing is performed after chip mounting is employed instead of a method in which electrode connection and resin curing are performed in a batch process.

This is due to the following reason.
The NCP connection method has a basic problem that the resin crawls up to the mounting tool and adheres to the tool during chip mounting. Therefore, conventionally, in order to prevent the resin from creeping up, the size of the holding portion is processed to be smaller than the size of the semiconductor chip. Therefore, the mounting tool cannot be provided with versatility. As described above, it is necessary to prepare a plurality of dedicated mounting tools when producing modules. In addition, since the NCP connection method performs electrode connection and resin curing in a batch process, the strength of the connection part of the semiconductor chip is greatly affected by the resin material used and its curing / shrinking state, so reliability There was a case lacking.

On the other hand, the mounting tool of the present invention must be formed larger than the semiconductor chip in order to provide versatility, that is, to enable continuous mounting with one tool regardless of the chip size and mounting angle. I had to. Therefore, the thermocompression bonding method in which the resin is applied after chip mounting does not cause the resin to creep, and is a very convenient method for the mounting tool of the present invention.
At the same time, in this construction method, the connection between the semiconductor chip and the circuit board is performed by metal bonding by solid phase diffusion of Au-Au, so that a high strength is obtained at the connection portion between the semiconductor chip and the circuit board, and the module reliability is improved. It has the merit that it can be improved.

The perspective view which shows the principal part structure of the flip chip bonding apparatus which concerns on this invention. It is explanatory drawing of the mounting tool which concerns on this invention, (a) is a figure which shows 1st Embodiment, (b) is a figure which shows 2nd Embodiment. The figure which shows the usage pattern of a mounting tool. The figure which shows the usage condition of the mounting tool different from FIG. The figure which shows the production process of the module by the flip chip bonding apparatus which concerns on this invention. The perspective view which shows the principal part structure of the conventional flip chip bonding apparatus. The figure which shows the circuit board which mounted the semiconductor chip. Explanatory drawing of the conventional mounting tool. The figure which shows the usage pattern of a mounting tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bonding head main body 2 Heater part 4 Flange part 5 Holding part 6 Through-hole 30 Circuit board 31 Semiconductor chip

Claims (2)

A movable bonding head main body, a heater portion attached to the bonding head main body, and a mounting tool having a through hole for suction and attached to the lower surface of the heater portion. In a flip chip bonding apparatus for mounting a held semiconductor chip on a circuit board while heating with the heater part,
The mounting tool includes a flange portion attached to the lower surface of the heater portion, and a lower flat holding portion provided on the lower surface of the flange portion and provided with a through-hole for suction at the center.
The flip chip bonding apparatus is characterized in that the holding portion is configured by concentrically arranging a plurality of columnar members in which the semiconductor chip is housed in one direction on the lower surface thereof. A movable bonding head main body, a heater portion attached to the bonding head main body, and a mounting tool having a through hole for suction and attached to the lower surface of the heater portion. In a flip chip bonding apparatus for mounting a held semiconductor chip on a circuit board while heating with the heater part,
The mounting tool includes a flange portion attached to the lower surface of the heater portion, and a lower flat holding portion provided on the lower surface of the flange portion and provided with a through-hole for suction at the center.
The holding part is a flip chip bonding apparatus characterized in that the semiconductor chip is formed of a cylindrical member or a prismatic member in which the semiconductor chip is accommodated in all directions on its lower surface.

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