JP3483443B2 - Air cylinder and bonding head unit having the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to an air cylinder for applying a bonding pressure when a semiconductor chip is bonded onto a substrate or the like, and a bonding head unit including the air cylinder.

[0002]

2. Description of the Related Art Conventionally, as a bonding head unit equipped with this type of air cylinder, Japanese Patent Laid-Open No. 9-1296 has been proposed.
The one described in Japanese Patent No. 87 is known. In this bonding head unit, a head holder is provided on the upper side of a bonding head having a collet so as to be able to rotate in the forward and reverse directions, and a rod extends from the head through the head holder on the upper side of the head holder. An air cylinder is in contact with this rod via a load cell.
When the bonding head unit descends and the collet of the bonding head presses the adsorbed semiconductor chip onto the substrate, the load cell detects the pressing force, and when this reaches a predetermined pressure, the operating air of the air cylinder is released and the semiconductor chip Is bonded.

In this case, in the air cylinder, the first piston is slidably attached to the cylinder body, and
A second piston is slidably mounted in a cylinder hole formed at the tip of the rod portion of the first piston.
A load cell is attached to the tip of the piston. A first supply port for supplying working air to the first piston is formed in the cylinder body, and a second supply port for supplying working air to the second piston is formed in the cylinder hole of the rod portion. Has been formed. The first piston has a large bore diameter and the second piston has a small bore diameter. For a semiconductor chip with a large bonding pressure,
Bonding is performed using the first piston, and bonding is performed using the second piston for semiconductor chips having a low bonding pressure.

[0004]

In such a conventional air cylinder, the first piston and the second piston are appropriately provided for semiconductor chips having different bonding pressures.
Can be used properly. However, since any piston receives sliding resistance from the cylinder body or the cylinder hole, there is a problem that the pressure value of the pressurized air tends to fluctuate and the bonding pressure tends to vary. In particular, in a multi-pin (flip chip) semiconductor chip, defective bonding is likely to occur. In addition, since the second piston is formed in the rod portion of the first piston, when using the second piston having a low pressure, it is necessary to keep the first piston in a fixed state. Since it is necessary to use the double-acting cylinder on the first piston side, there is a problem that the structure including the circuit configuration becomes complicated.

The present invention provides an air cylinder which has a simple structure and is capable of applying appropriate and stable pressure to various pressure objects having large and small pressure ranges, and a bonding head unit including the air cylinder. The purpose is to do.

[0006]

An air cylinder according to the present invention comprises a cylinder body, a piston housed in the cylinder body so that the cylinder can move forward and backward, and a plurality of air bearings that support the piston in the cylinder body so that the piston can move forward and backward. , One or more pressure receiving parts having different pressure receiving areas from the piston head of the piston are formed in the body part of the piston, and the piston head and the one or more pressure receiving parts are partitioned by a plurality of air bearings to form a plurality of parts including the piston head part. The pressure receiving chamber is configured so that working air can be selectively supplied to multiple pressure receiving chambers.
Configuration, and by switching the supply of working air to multiple pressure receiving chambers.
It is characterized in that different thrusts that generate a pressing force are generated .

According to this configuration, when the working air is supplied to the pressure receiving chamber formed in the piston head portion, a pressure corresponding to the pressure receiving area of the piston head is obtained, and the pressure receiving chamber formed in the pressure receiving portion is provided. If the working air is strengthened, a pressure force corresponding to the pressure receiving area of the pressure receiving portion can be obtained. Therefore, by the pressure receiving area of the pressure receiving area and the pressure receiving portion of the piston head are different, also by the pressure receiving area between the pressure receiving portion is different, different
Then, the thrust force is generated, and the pressing force in different ranges can be obtained. Therefore, the pressing force can be selected according to the object to be pressed. On the other hand, since the piston is moved back and forth through the air bearing, the sliding resistance can be made almost zero, and the fluctuation of the pressing force due to the sliding resistance can be eliminated.

In this case, it is preferable that the pressure receiving portion is constituted by a step portion formed in an annular shape on the body portion of the piston.

According to this structure, the pressure receiving portion can be easily formed on the body portion of the piston by a lathe or the like.

The bonding head unit of the present invention is characterized in that the air cylinder according to claim 1 or 2 is provided above the bonding head.

According to this structure, by properly using the pressure receiving chamber of the air cylinder, various semiconductor chips having different bonding pressures can be bonded accurately and stably.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An air cylinder according to an embodiment of the present invention and a bonding head unit (hereinafter referred to as "head unit") including the same are applied to a die bonder with reference to the accompanying drawings. The case will be described. Figure 1 is a side view of the main parts of the die bonder.
As shown in the figure, the die bonder 1 is lifted and lowered by the lifting device 3 supported by the machine base 2, and
A head unit 4 including a unit body 5 and two bonding heads 6 and 6, an engagement position at which the two bonding heads 6 and 6 are engaged with the unit body 5, and a suction position at which the semiconductor chip C is sucked. And a head transport device 7 that swivels between them. When the semiconductor chip C is supplied to the die bonder 1, the bonding head 6 pivoted to the suction position sucks the semiconductor chip C. Subsequently, the bonding head 6 is transported to the engagement position by the head transport device 7 and engages with the unit body 5. Here, the elevating device 3 is driven to lower the head unit 4 to bond the adsorbed semiconductor chip C onto the substrate B.

The lifting device 3 includes a lifting motor 11 fixed to the machine base 2 and a lifting motor 11 via a coupling 12.
And a ball screw 13 rotatably attached to the. The ball screw 13 is screwed into a female screw member 21 of the head unit 4 to be described later, and the forward / reverse rotation of the lifting motor 11 causes the head unit 4 to bond through the ball screw 13 and the female screw member 21. Go up and down.

The unit body 5 of the head unit 4 includes an engaging claw 15 that engages with the bonding head 6 at the engaging position, a transmission rod 16 arranged so that its lower end abuts against the upper end of the bonding head 6, and a lower end. Part to engage claw 1
5, a support arm 17 that supports the transmission rod 16 slidably in the vertical direction, a load cell 18 that abuts on the upper end of the transmission rod 16, and a load cell 18 that holds the load cell 18 and is disposed above the load cell 18. Air cylinder 19 and the air cylinder 19 and support arm 1 at the bottom
7 and a frame member 20 that supports the female screw member 21 at the upper portion.

The frame member 20 and the support arm 17 are slidably engaged with a main guide rail 22 fixed to the machine base 2, and the main guide rail 22 is rotated by the rotation of the lifting motor 11.
It is guided by and goes up and down. A stopper plate 23 is fixed to the lower part of the main guide rail 22, and the stopper plate 2
The tip of 3 comes into contact with the engaging claw 15 that has been raised to the home position. The engagement claw 15 is rotatably attached to the support arm 17 in a state of being urged counterclockwise in the drawing, and the abutment portion formed on the upper end portion of the bonding head 6 is hooked on the tip thereof. ing.

More specifically, the abutting portion 24 of the bonding head 6 is sandwiched by the transmission rod 16 facing the upper side and the engaging claw 15 facing the lower side, and moves up and down in this state. When the unit main body 5 rises to the home position in the up-and-down operation, the engaging claw 15 hits the stopper plate 23, and the engaging claw 15 rotates in the process of further raising the unit main body 5 to the rising end position. The bonding state with the abutting portion 24 is released so that the bonding head 6 is left behind.

The transmission rod 16 connects the bonding head 6 and the air cylinder 19 via the load cell 18, and the reaction force received when the bonding head 6 bonds the semiconductor chip C is transferred to the air via the load cell 18. It is transmitted to the cylinder 19. That is, the air cylinder 19 applies a bonding pressure to the bonding head 6, and the load cell 18 detects the bonding pressure when applying the pressure. When the head unit 4 descends and moves to the bonding operation, the air cylinder 19 applies a bonding pressure to the bonding head 6. Here, when the load cell 18 detects a predetermined bonding pressure, the working air of the air cylinder 19 is evacuated (pressure drop) and the bonding head 6 shifts to an ascending operation via a controller and a pneumatic circuit (not shown). .

The head transfer device 7 includes a head holder 31 for supporting the two bonding heads 6 and 6 in a 180-degree point-symmetrical position, a support table 32 for rotatably supporting the head holder 31, and a head via a belt 33. Holder 3
1 and a conveyance motor (not shown) for rotating 1. The head holder 31 is rotatably supported by a support table 32 fixed to the machine base 2 via a pair of bearings 34, 34 that are arranged one above the other. Then, by the forward / reverse rotation of the transport motor, the head holder 31 reciprocally rotates through the belt 33 at an angle of 180 degrees. As a result, one bonding head 6 that has sucked the semiconductor chip C at the suction position is rotated (revolved) and conveyed to the engagement position, and the other bonding head 6 that has completed the bonding and is at the engagement position is It is rotated (revolved) and conveyed to the suction position.

An annular guide groove 35 having a U-shaped cross section is formed on the lower peripheral surface of the support table 32, and each bonding head 6 is guided by the annular guide groove 35 via a roller 25. Rotate (revolve). Further, a lower member is cut out at a portion on the engagement position side of the annular guide groove 35, and the bonding head 6 is separated from this portion and descends. That is, when the bonding head 6 moves from the suction position to the engagement position, the unit body 5 is at the rising end position, and the engagement state between the engagement claw 15 and the bonding head 6 is released. When the head transport device 7 is driven, a pair of bonding heads 6, 6
Are guided by the annular guide groove 35 and rotate at the same time (revolution)
To do. When the swivel conveyance of the bonding heads 6 and 6 is completed, the unit main body 5 starts descending from the rising end position, holds the bonding head 6 when passing the home position, and further descends for bonding. Reference numeral 36 in the drawing is a sub-guide rail that guides the lowering of the bonding head 6, and reference numeral 26 is a collet attached to the lower end of the bonding head 6 to adsorb the semiconductor chip C.

Here, the air cylinder 19 which is a characteristic part of this embodiment will be described in detail with reference to FIG. As shown in the figure, the air cylinder 19 includes a cylinder body 41 and a piston 42.
Is supported in the cylinder body 41 by a first air bearing 43 and a second air bearing 44 so as to be movable back and forth. The load cell 18 is attached to the lower end of the piston 42. A wide annular groove 45 is formed in the upper portion of the piston 42, the first air bearing 43 faces this portion, and a pressure receiving portion having a pressure receiving area smaller than that of the piston head 47 is formed in the lower step portion 46. .

That is, the first air bearing 43 is opposed to the annular groove 45 of the piston 42, and the second air bearing 44 is opposed to the body portion 48 of the piston 42. , 44 form a first pressure receiving chamber 50 having the piston head 47 as a pressure receiving portion and a second pressure receiving chamber 51 having the stepped portion 46 as a pressure receiving portion. In response to this, the cylinder body 41 has a first supply port 52 for supplying working air to the first pressure receiving chamber 50,
A second supply port 53 for supplying operating air to the second pressure receiving chamber 51 and an exhaust port 54 corresponding to these two supply ports 52, 53 are formed. Further, the cylinder body 41 is formed with a first pressure port 55 for supplying discharge air to the first air bearing 43 and a second pressure port 56 for supplying discharge air to the second air bearing 44. There is.

In such a configuration, the discharge air is supplied to the first air bearing 43 and the second air bearing 44 via both the first and second pressurizing ports 55 and 56, so that the piston 42 moves to the cylinder. It floats in the main body 41 and can be moved back and forth without any sliding resistance. Then, in this state, when the working air is supplied to the first pressure receiving chamber 50 via the first supply port 52, the piston head 47
A large thrust corresponding to the pressure receiving area of is generated. Further, when the working air is supplied to the second pressure receiving chamber 51 through the second supply port 53 by switching the valve, a small thrust corresponding to the pressure receiving area of the step portion 46 is generated.

That is, the above thrust is applied to the semiconductor chip C.
Of the various semiconductor chips C, the bonding is performed using the first pressure receiving chamber 50 in the heavy bonding with a relatively large bonding pressure, and the soft bonding with a relatively small bonding pressure is performed. Bonding is performed using the second pressure receiving chamber 51. More specifically, the bonding pressure as the reaction force of the substrate B, which rises as the bonding head 6 descends, is detected by the load cell 18 attached to the piston rod 49, and this bonding pressure is the type of the semiconductor chip C. When the predetermined pressure is reached for each, the working air is released to complete the bonding.

As described above, according to the air cylinder 19 of the present embodiment, the size of the piston 2 is the same.
Different types of bonding pressure can be obtained. That is,
A large bonding pressure can be obtained by using the first pressure receiving chamber 50, and a small and fine bonding pressure can be obtained by using the second pressure receiving chamber 51. In addition, the first and second air bearings 4
By using 3, 44, it is possible to prevent pressure fluctuation of the bonding pressure due to the sliding resistance of the piston 42.
Therefore, more appropriate bonding pressure can be accurately and stably applied to various semiconductor chips C,
The frequency of defective bonding can be reduced.

In the air cylinder of this embodiment, two pressure receiving chambers are formed. However, by forming a step portion in the piston and partitioning these with air bearings, there are three or more pressure receiving chambers. Can also be configured. Needless to say, this air cylinder can be applied to other than bonding semiconductor chips.

[0026]

According to the air cylinder of the present invention as described above, according to the present invention, as well as movably supporting the piston in the air cylinder, constitute plural pressure receiving chamber to the air cylinder itself, operated
Pressure is not applied by switching the supply of air to multiple pressure receiving chambers.
Since different thrusts are generated , an appropriate and stable pressing force can be applied to various types of pressurized objects having large and small pressure ranges with a simple structure. In addition,
The pressure part is a stepped part formed in an annular shape on the body part of the piston.
Since it is configured with a lathe, the body of the piston can be
The pressure receiving portion can be easily formed. Further, if this air cylinder is applied to a bonding head unit, it is possible to apply a bonding pressure in a wide range with high accuracy, suppress a bonding failure, and form a highly reliable unit.

[Brief description of drawings]

FIG. 1 is a side view of a die bonder including an air cylinder and a bonding head unit according to an embodiment of the present invention.

FIG. 2 is a cut side view of the air cylinder according to the embodiment.

[Explanation of symbols]

1 die bonder 4 head unit 5 unit body 6 Bonding head 19 Air cylinder 41 Cylinder body 42 piston 43 First Air Bearing 44 Second air bearing 45 annular groove 46 steps 47 piston head 48 torso 50 First pressure chamber 51 Second Pressure Chamber

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-117912 (JP, A) JP-A-8-159106 (JP, A) JP-A-10-340931 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/60 H01L 21/603 H01L 21/52 F15B 15/14

Claims (3)

(57) [Claims] 1. A cylinder body, a piston housed in the cylinder body so that the piston can move forward and backward, and a plurality of air bearings that support the piston in the cylinder body so that the piston can move forward and backward. Forming one or more pressure receiving portions having different pressure receiving areas from the piston head of the piston, and dividing the piston head and the one or more pressure receiving portions by the plurality of air bearings, respectively, a plurality of pressure receiving portions including a portion of the piston head. Make up the room,
Operation air can be selectively supplied to the multiple pressure receiving chambers
It is configured to cut off the supply of the working air to the plurality of pressure receiving chambers.
An air cylinder characterized in that different thrusts that generate a pressing force are generated by replacement. 2. The air cylinder according to claim 1, wherein the pressure receiving portion is constituted by a step portion formed in an annular shape on a body portion of the piston. 3. A bonding head unit comprising the air cylinder according to claim 1 or 2 above a bonding head.