JPH11274184A - Apparatus for feeding solder to chip bonder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for feeding solder to a chip bonder, wherein a solder material is commonly used for various chip sizes to eliminate the need for changing over according to the type of chips, the index hardly changes against the chip size and unwanted heat wall not be exposed to an unused solder material. SOLUTION: This apparatus comprises a solder pot 61 for storing spherical solder pieces 80 and a suction head 62 which chucks and holds to carry the solder pieces 80 to a solder feed position P and puts on island 3 of a lead frame, the chucking head 62 is replaceable with one for chucking the number of solder pieces according to the chip type, the solder pot 61 causes the solder pieces 80 to jump with air blown up from the bottom when the suction head 62 chucks the solder pieces 80 in the solder pot 61, and CCD sensor 64 for verifying the number of solder pieces 80 that the suction head 62 chucks is disposed on the way of carrying the solder pieces chucked by the suction head 62 onto the island 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder supply device for a chip bonder, and more particularly to a solder supply device suitable for sharing the chip bonder with products having different chip sizes.

[0002]

2. Description of the Related Art In some cases, solder such as solder is used to bond a semiconductor chip to a substrate such as an island or a stem of a lead frame. An example of this type of conventional apparatus will be described with reference to the drawings. FIG. 2 is a side sectional view conceptually showing this. When the lead frame is fed on the heat block 2 from the left to the right in the heat rail 1 and the island 3 of the lead frame is stopped at a predetermined solder supply position, the lead frame is heated by the heat block 2 to a temperature at which the solder melts. I have. Then, a cover plate 4 covered so as to keep the inside of the heat rail 1 in a non-oxidizing atmosphere.
Is provided with a hole 5 from which solder is supplied onto the island 3 by a solder supply device 6.

In the solder supply device 6, a linear solder 8 wound on a reel 7 is set on a feed roller 9 so as to be able to advance and retreat according to the rotation direction, and the tip of the solder 8 is a nozzle located in the hole 5 of the cover plate 4. 10 is passed. The nozzle 10 moves up and down through the hole 5.

When supplying the solder 8 to the island 3, the nozzle 10 first descends while holding the tip of the solder 8 therein, thereby bringing the tip closer to the island 3 to minimize the variation in the solder supply position. Subsequently, when the feed roller 9 rotates and sends the solder 8 toward the island 3, the portion of the solder 8 in contact with the island 3 melts and adheres to the island 3. When a predetermined length is fed, the feed roller 9 rotates in the reverse direction and pulls back so that the tip of the solder 8 is located at the tip of the nozzle 10 or within the nozzle, and the nozzle 10 rises to move the tip away from the island 3. Thereafter, the lead frame is sent, the next island 3 is set, and the above-described solder supply operation is repeated.

[0005]

However, in a case where the above-described conventional device is used for both a type in which a small chip is bonded to a small island and a type in which a large chip is bonded to a large island, the small chip is used for the small island. In the case of bonding, as shown in FIG. 3A, one point of the solder 8 may be supplied on the small island 3a, and the amount may be small. In order to supply a small amount with good reproducibility, it is necessary to secure a certain size of the feed as a thin material. When bonding a large chip to a large island 3b as shown in FIG. 3b with this apparatus, a large amount of solder 8 must be supplied.
If a solder having a thickness suitable for supplying a small amount is used, it takes a long time to feed and the index of the bonding operation becomes slow. Therefore, it is necessary to reset the solder having a wire diameter suitable for a necessary supply amount, and the adjustment is complicated, which not only lowers the productivity, but also a large amount of solder is supplied to one place as shown in FIG. However, the process cannot be performed well, and a step of expanding the solder supplied to the subsequent process is required, and the apparatus becomes complicated. Therefore, as shown in FIG. 3c, it is conceivable that the supply amount of each solder is distributed to a large island 3b and supplied to multiple points as a small supply like the supply amount of the solder shown in FIG. 3a. Then, the diameter of the solder to be used can be shared with the case where a small amount of solder is supplied to a small island shown in FIG. 3A, and the total supply amount can be adjusted by the number of supplied points, and the solder 8 is dispersed. There is no need to provide a spreading step since it is supplied. However, in order to supply the solder 8 to multiple points with this apparatus, the nozzle 10 or the lead frame must be movable in the XY direction, which not only complicates the mechanism, but also requires time to supply the solder in each point order. The index of the bonding operation becomes slow. Further, in the solder supply method using the above-described apparatus, the vicinity of the tip of the solder 8 which has been supplied and pulled back is not melted but is a high temperature portion just before melting, and the inside of the heat rail 1 is in a nitrogen atmosphere. Nevertheless, it is difficult to prevent the surface from being oxidized due to mixing of some oxygen because of not being in a completely closed state, and the oxide is mixed into the next solder to be supplied. Therefore, the present invention eliminates the need to share the solder material corresponding to the type by sharing chip sizes of different sizes, the index does not substantially change depending on the chip size, and unnecessary heat is not applied to the unused solder material, so that oxidation is not performed. Provide a supply device for a small amount of solder.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a solder supply in a chip bonder for supplying solder to a substrate heated and arranged at a solder supply position and thereafter bonding a chip on the solder. The apparatus comprises: a solder pool for storing solder pieces of a predetermined shape; and a suction head for suction-holding and transferring the solder pieces and placing the solder pieces on a base material arranged at a solder supply position. The solder supply device is characterized in that it is configured to adsorb a number of solder pieces corresponding to the above and to be replaceable. According to the above configuration, a suction head for sucking a small number of, for example, one solder piece may be used for a product with a small chip size, and the number and arrangement may be selected so as to have a necessary amount of solder for a product with a large chip size. . Therefore, since the same solder piece is simultaneously supplied in the case of a product having a large chip size as in the case of a product having a small chip size, the time required for the supply is not so long as compared with the case of supplying one piece for a product having a small chip size.
Further, since the temperature of the solder reservoir does not become high, the solder does not oxidize.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solder supply device according to the present invention is, for example, a substrate such as a stem or an island of a lead frame which is arranged at a solder supply position while being heated on a heat rail and heated to a melting temperature of the solder. It is provided on a chip bonder for supplying a solder thereon and bonding a chip such as a semiconductor chip thereon. The solder may be a so-called soft solder such as an Sn-Pb alloy or an Ag-Pb-Sn alloy or a hard solder such as an Au-Si alloy. The shape of the solder is preferably spherical because it has no directionality, but other shapes such as a dice shape are also possible. The size can be selected according to the chip size of the kind to be applied. In the case of a small chip, a small amount of solder pieces is used, and in the case of a large chip, a large amount is used to obtain an appropriate amount of solder.

[0008] The solder supply device of the present invention includes a solder reservoir for storing such solder pieces. And
A large number of solder pieces are inserted without particular alignment. A suction head, which is designed according to the product type, is provided with one or a plurality of solder pieces sucked and held by vacuum suction and transferred onto a base material arranged at a solder supply position. The suction head can directly suck the solder pieces of the solder pool. The suction head is lowered to be positioned very close to the upper surface of the solder piece (for example, the contact is confirmed by a pressure sensor and lifted up a little) to activate the vacuum suction. In this case, if the number of solder pieces to be adsorbed is large, a portion where the solder is not adsorbed may occur. Therefore, it is preferable to shake or vibrate the suction head or the solder reservoir during the suction operation in order to perform the suction more completely. Alternatively, the suction head may be lowered into the solder piece while the solder piece is jumping. The suction head holding and holding the solder pieces rises, moves in the horizontal direction, reaches the base material located at the solder supply position, stops suction, turns the solder on the base material, and puts the solder on the base. It can be configured to transport the pieces. A CCD sensor, etc., is installed to check for any missing solder pieces during the transfer, and if the sucked solder pieces are insufficient, return to the solder pool and add suction action. Is preferred. When the suction head places the solder piece on the base material, it can be lowered until the solder piece contacts the base material. If the solder pieces come into contact with the base material, they melt and mount on the base material.However, if they are too melted, they may adhere to the suction head. Therefore, it is better to apply a surface treatment to the material that does not wet the solder or to prevent it from getting wet. . It is also possible to stop immediately before the solder piece comes into contact with the base material to stop the suction and drop the solder piece. This is advantageous because less heat is transmitted to the suction head.

The suction head is appropriately designed and prepared for each type of product to be applied, and is easily configured to be replaced when the type is changed.

[0010]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view thereof. In the figure, a lead frame is fed in a heat rail (not shown) from left to right in the drawing (X direction), and the island 3 is heated to the melting temperature of the solder and stopped at the solder supply position P. A solder supply device 60 is provided behind the solder supply position P (in the Y direction) to supply the solder onto such an island 3. The solder supply device 60 includes a box-shaped solder reservoir 61 on a stage (not shown), in which a number of spherical solder pieces 80 are placed. And solder pool 61
Then, the air blows up from the bottom and the solder pieces 80 inside are floating and jumping. Further, a suction head 62 is provided. The suction head 60 has a lower surface of an area corresponding to the range of the solder supply arrangement of the kind to be applied, and has suction holes (not shown) of that number, and is connected to a vacuum system (not shown) by piping (not shown). , Is detachably attached to the lower end of the shaft 63.
Is moved in the vertical (Z) direction and in the front and rear (Y) direction by the movement of the solder piece 80, the solder piece 80 in the solder reservoir 61 is sucked, transferred, and placed on the island 3. A one-dimensional CCD sensor 64, for example, is disposed below a path through which the suction head 62 sucks, holds, and transfers the solder pieces 80, and checks the number of the sucked solder pieces 80.

Next, the operation of this device will be described. (1) First, the suction head 62 descends into the solder reservoir 61, and when vacuum suction is started, the rising solder pieces 80 are sucked into suction holes (not shown) by the blowing air. (2) After maintaining the state for a predetermined period of time such that the solder pieces 80 are considered to be sucked in all the suction holes (not shown), the suction head 62 is lifted while maintaining the suction, and the solder supply position is maintained. Move toward P. CC placed in the middle
It is confirmed whether the number of the solder pieces 80 to which the D sensor 64 is adsorbed is not insufficient. (3) If the result of the check is insufficient, the suction head 62 returns and repeats the operations (1) and (2). If it is not insufficient, it moves to the solder supply position as it is, descends, stops the vacuum suction, and places the solder piece 80 on the island 3. At this time, the suction head 62 stops in a state where the solder pieces 80 do not come into contact with the islands 3 and leave a fine space therebetween, so that the solder balls being sucked do not melt and come into contact with the islands 3 after dropping and melt. (4) Next, the suction head 62 returns to the inside of the solder reservoir 61 to suction the solder pieces 80. During this time, the lead frame is conveyed, and the next island 3 is set at the solder supply position P. (5) Thereafter, the operations of (2) to (5) are repeated, and solder is sequentially supplied.

According to the above embodiment, the number of solder pieces to be supplied is selected according to the chip size, and the suction head having the suction holes of the number is used. Therefore, when the type is changed, the suction head is changed. Thus, the solder can be supplied without changing the solder pieces, and since a large number of solder pieces are supplied at once in a variety having a large chip size, a decrease in index is small. Further, since the temperature of the solder reservoir does not become high, the solder does not oxidize.

In the above embodiment, the solder pieces 80 in the solder reservoir 61 are made to fly by blowing air from the bottom, but they may be made to fly by applying vibration.

[0014]

As described above, according to the apparatus of the present invention, a chip type can be shared between a small chip size type and a large chip size type at the same speed as a small type type. It is not necessary to prepare solder material for each product type. Further, since the temperature of the solder reservoir does not become high, the solder does not oxidize.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an embodiment of the present invention.

FIG. 2 is a side sectional view conceptually showing a conventional device.

FIG. 3 is a plan view showing a state where solder is supplied to the island.

[Explanation of symbols]

 P Solder supply position 3 Island (base material) 60 Solder supply device 61 Solder reservoir 62 Suction head 64 CCD sensor (sensor) 80 Solder piece

Claims (3)

[Claims] 1. A solder supply device for a chip bonder for supplying solder to a substrate heated at a solder supply position and thereafter bonding a chip to the solder, wherein a solder piece having a predetermined shape is stored. And a suction head that sucks, holds and transfers the solder pieces and places it on a base material placed at a solder supply position, and the suction head is one that sucks the number of solder pieces according to the type and is replaceable. Solder supply device for chip bonder, characterized in that: 2. A solder supply device for a chip bonder, wherein when the suction head sucks the solder pieces in the solder pool, the solder pieces are jumped by air blown up from the bottom of the solder pool. 3. The chip bonder according to claim 1, wherein a sensor for confirming the number of solder pieces adsorbed by the suction head is disposed while the suction head sucks and holds the solder pieces and transfers the solder pieces onto the substrate. Solder supply equipment.