JP2000091360A - Bonding device and flat-surface forming method of bonding head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively perform the adjustment of the flat-surface forming of a bonding head. SOLUTION: A chip-chucking valve is turned on, immediately before a head part 6 is lowered by a lifting device and a bonding head 26 comes into contact with a stage surface. A chip-chucking face 53 adsorbs the stage surface, and the flat-surface formation is adjusted. Thereafter, a heat-chucking valve is turned on, and the bonding head 26 is adsorbed and in the state in which the flat surface of a head holding part 28 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding apparatus for bonding a semiconductor chip to which a bonding head is vacuum-sucked to a substrate, and a suction surface of the bonding head is brought into contact with a stage surface to change a holding angle position with respect to a head holding portion. Then, the present invention relates to a bonding head flattening method in which the bonding head is again vacuum-sucked and held by the head holding unit to flatten the bonding head.

[0002]

2. Description of the Related Art According to the prior art of this type of bonding apparatus, the flattening of the suction surface of a bonding head is performed when a semiconductor chip (die) cut from a wafer is mounted on a lead frame or a substrate. It is important to maintain the mounting accuracy. However, it is very difficult to process the bonding head by taking the parallelism into account, and it is necessary to replace the chip depending on the type of chip. At the time of the replacement, the parallelism of the suction surface may not be obtained.
For this reason, it is necessary to adjust the parallelism of the suction surface of the bonding head in accordance with the surface of the substrate to be mounted (plan out).

[0003] For this reason, for example, a spherical profiled surface is formed on the upper part of the bonding head, and a suction port for vacuum-suctioning the profiled surface is provided in a head holding portion for holding the bonding head so that the surface is sucked and held. I have to. That is, by forming an engaging portion with which the profiling surface is engaged with the head holding portion, the profiling surface moves along the engaging portion,
The angle of the bonding head is changed, so that the paralleling can be adjusted. To adjust the parallelism, the suction surface of the chip of the bonding head is brought into contact with the reference stage surface, and then the bonding head is suction-held and fixed by vacuum suction of the head holding unit to hold this position.

[0004]

However, in the above-mentioned prior art, it is necessary to take a certain amount of time for the bonding head to come into contact with the stage surface and to adsorb it by the head holding portion while maintaining the parallelism. When the head holding unit vacuum-suctions the bonding head, the shock may shift the parallelism.

SUMMARY OF THE INVENTION It is an object of the present invention to surely adjust the plane of the bonding head.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to bonding a semiconductor chip to which a bonding head is vacuum-sucked to a substrate, wherein the head holding section holds and fixes the bonding head by vacuum suction, and the head holding section. And a holding angle changing mechanism that can change the holding angle position of the bonding head with respect to the head holding unit when the vacuum suction of the unit is released. A stage surface serving as a reference for performing, elevating means for elevating the head holding unit, a chip suction valve which opens and closes for vacuum suction of the semiconductor chip by the bonding head and release thereof,
A head suction valve that opens and closes for vacuum suction and release of the bonding head by the head holding unit, and the chip before the bonding head comes into contact with the stage surface when the elevating unit lowers the head holding unit. The suction valve is opened to perform vacuum suction, and thereafter, a control means for controlling the chip suction valve and the head suction valve so that the head holding unit vacuum suctions the bonding head is provided.

According to the present invention, the holding angle changing mechanism is relatively movable along a surface formed on the head holding portion or the bonding head, and the holding portion vacuum-sucks the bonding head. An engaging portion that sometimes engages with the profiled surface and angularly positions the bonding head on the head holding portion.

In the present invention, the profiled surface is a part of a spherical surface.

Further, according to the present invention, when the vacuum suction of the head holding unit is released, the suction surface of the bonding head is brought into contact with a reference stage surface, the holding angle position with respect to the head holding unit is changed, and the head holding unit is again used. A bonding head flattening method for holding a bonding head by vacuum suction and flattening a bonding head, comprising: a head lowering step of lowering a head holding unit; and a stage surface suctioning step of vacuum suctioning a stage surface to the bonding head. And a head holding step of holding the bonding head at an angular position that is flattened by vacuum-suctioning the bonding head in the head holding unit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a side view of a main part of a die bonder 1 which is a bonding device. As shown in FIG. 2, the die bonder 1 is lifted and lowered by a lifting device 3 supported by a machine base 2 and a lifting device 3. At the same time, the head unit 4 composed of the unit main body 5 and the two head portions 6, 6 and the engaging position where the two head portions 6, 6 are engaged with the unit main body 5 and the semiconductor chip C are sucked. And a head transfer device 7 that turns and conveys to and from the suction position. When the semiconductor chip C is supplied to the die bonder 1, the head unit 6 that has turned to the suction position sucks the semiconductor chip C. Subsequently, the head section 6 is transported to the engagement position by the head transport device 7 and engages with the unit body 5. Here, the lifting / lowering device 3 is driven to lower the head unit 4 to bond the sucked semiconductor chip C onto the substrate B.

The elevating device 3 includes an elevating motor 11 fixed to the machine base 2 and an elevating motor 11 via a coupling 12.
And a ball screw 13 which is rotatably mounted on the ball screw 13. The ball screw 13 is screwed to a female screw member 21 of the head unit 4 described later, and the head unit 4 is bonded through the ball screw 13 and the female screw member 21 by the forward / reverse rotation of the lifting / lowering motor 11. To go up and down.

The unit main body 5 of the head unit 4 includes an engaging claw 15 that engages with the head portion 6 at the engaging position, a transmission rod 16 disposed so that the lower end abuts against the upper end of the head portion 6, and a lower end. While holding the engaging claw 15 in the part,
A support arm 17 for slidably supporting the transmission rod 16 in the vertical direction, a load cell 18 in contact with the upper end of the transmission rod 16, an air cylinder 19 for holding the load cell 18 and disposed above the load cell 18; While supporting the air cylinder 19 and the support arm 17 at the lower part,
And a frame member 20 that supports the female screw member 21 at the upper part.

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
Guided to go up and down. A stopper plate 23 is fixed to a lower portion of the main guide rail 22, and the stopper plate 2
The tip of 3 is in contact with the engaging claw 15 that has risen to the home position. The engagement claw 15 is rotatably attached to the support arm 17 in a state where the engagement claw 15 is urged counterclockwise in the figure, and abuts a butting portion formed at the upper end of the head portion 6 at the tip thereof. ing.

More specifically, the abutting portion 2 of the head portion 6
4 is sandwiched between 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. Also,
In the elevating operation, when the unit main body 5 rises to the home position, the engaging claws 15 abut against the stopper plate 23, and in the process of further raising the unit main body 5 to the rising end position, the engaging claws 15 rotate, The latching state with the abutting portion 24 is released so that the head portion 6 is left behind.

The transmission rod 16 connects the head section 6 to the air cylinder 19 via a load cell 18, and receives a reaction force received when the head section 6 bonds the semiconductor chip C via the load cell 18. The power is transmitted to the cylinder 19. That is, the air cylinder 19 applies a bonding pressure to the head portion 6, and when applying the pressure, the load cell 18 detects the bonding pressure. When the head unit 4 moves down to perform the bonding operation, the air cylinder 19 applies a bonding pressure to the head unit 6. Here, when the load cell 18 detects a predetermined bonding pressure, the operating air of the air cylinder 19 is removed (pressure drop) via the controller and the pneumatic circuit (not shown), and the head unit 6 shifts to the rising operation. .

The head transport device 7 includes two head units 6,
Head Holder 31 Supporting 6 at 180 ° Point Symmetry Position
A support table 32 that rotatably supports the head holder 31; and a transport motor (not shown) that rotates the head holder 31 via a belt 33. The head holder 31 is provided with a pair of bearings 3 arranged one above the other.
Support table 32 fixed to machine base 2 via
It is supported rotatably. When the transport motor rotates forward and backward, the head holder 31 reciprocates at an angle of 180 degrees via the belt 33. This allows
One of the heads 6 that has sucked the semiconductor chip C at the suction position
Is rotated (revolved) and conveyed to the engagement position, and the other head 6 at the engagement position after completing the bonding is
It is rotated (revolved) and transported to the suction position.

An annular guide groove 35 having a U-shaped cross section is formed in the lower peripheral surface of the support table 32.
Is rotated (orbits). In addition, the annular guide groove 3
5, a lower member is cut off at a portion on the engagement position side, and the head portion 6 separates from this portion and descends. That is, when the head portion 6 moves from the suction position to the engagement position, the unit body 5 is at the rising end position,
The engagement state between the engagement claw 15 and the head portion 6 is released.
When the head transport device 7 is driven, a pair of head units 6, 6
Is guided by the annular guide groove 35 and rotates (revolves) at the same time.
I do. When the swivel conveyance of both head parts 6, 6 is completed,
The unit body 5 starts descending from the rising end position, holds the head portion 6 when passing through the home position, and further descends for bonding. Note that reference numeral 36 in FIG.
Reference numeral 26 denotes a sub-guide rail for guiding the lowering of the head unit 6, and reference numeral 26 denotes a bonding head mounted on the lower end of the head unit 6 for sucking the semiconductor chip C.

The head section 6 will be described below with reference to FIGS.

The head portion 6 is composed of a bonding head 26 and a head holding portion 28 for holding the bonding head 26. A convex spherical surface 38 is formed on the upper portion of the bonding head 26. An engagement surface 40 is formed on the lower surface of the surface 28 as an engagement portion having a spherical shape having the same radius as the contour surface. The engagement surface 40 is fitted to the contour surface 38 without any gap. The copying surface 38 can be swung in all directions about the center.

A hole 41 is opened above the profile surface 38 of the bonding head 26, and a hole 43 is also opened at a position facing the head holding portion 28. The support arm 44 and the hole 41 in the hole 43 of the head holding unit 28
A tension spring 46 is provided between the inner supporting rod 45 and the hole 41,
The bonding head 26 is suspended by the spring. Also, the head holding unit 2
At the lower part of 8, a fall prevention plate 47 for preventing the bonding head 26 from falling is attached.

A concave portion 48 is formed in a portion of the head holding portion 28 facing the profile surface 38 so as to be a gap even when the profile surface 38 is in close contact with the engagement surface 40. The recess 48
A head suction vacuum passage 50 is opened at the opening, and serves to hold and fix the bonding head 26 to the head holding unit 28 by communicating with a vacuum source (not shown) under vacuum.
The recess 48 forms a vacuum chamber. Therefore, the bonding head 26 can be fixed at a position where the copying surface 38 is inclined at an arbitrary angle when viewed from the side in an arbitrary direction in plan view.

As shown in FIG. 3, the chip suction vacuum passage 51 is provided on the chip suction surface 53 of the bonding head 26.
It is open to.

Next, a control block of the die bonder 1 will be described with reference to FIG.

The head suction vacuum passage 50 communicates with a head suction valve 55, and the chip suction vacuum passage 51 communicates with a chip suction valve 56. The respective valves 55 and 56 are turned on / off. To switch between vacuum suction and release.

The switching of the valves 55 and 56 is controlled by a CPU 58 via an interface 57, respectively.
The CPU 58 performs given control of the die bonder 1 in accordance with a program stored in the ROM 60 based on various data stored in the RAM 59.

The interface 57 is connected to the elevating motor 11.

The operation will be described below.

First, a description will be given of the operation of flattening (parallelizing) the chip suction surface 53 of the bonding head 26.

This operation is performed when the power to the die bonder 1 is turned on.

That is, the head unit 6 is lowered along the sub guide rail 36 by the driving of the lifting motor 11. At this time, the valve 55 and the valve 56 are OFF, the vacuum passages 50 and 51 are not suctioned, and the bonding head 26 is suspended only by the spring 46.

Next, immediately before the head 26 comes into contact with the stage surface 62 on which the substrate B is not mounted, the chip suction valve 56 is turned on, and when the suction surface 53 comes into contact with the stage surface 62, the bonding head 26 Sucks the stage surface 62, and the suction surface 53 becomes parallel to the stage surface 62. At this time, the copying surface 38 is aligned with the engagement surface 40 in accordance with this movement.

Next, the head suction valve 55 is turned on, the head suction vacuum passage 51 starts vacuum suction, and the bonding head 26 follows the head holding part 28 on the surface 38.
Is fixed without changing the positional relationship between the and the engagement surface 40. At this time, the suction surface 53 is suctioning the stage surface 62, and even if there is a shock or other vibration due to the vacuum suction of the head suction vacuum passage 51, the bonding head 26 is accurately placed on the flat surface. Is fixed.

Next, the chip suction valve 56 is turned off, and the vacuum of the chip suction vacuum passage 51 is released.

Thus, the bonding head 26
Is finished.

The above-mentioned plane setting operation is performed by the ROM 6
0 or the like, and may be automatically performed under the control of the CPU 58 after the power is turned on. Alternatively, when the worker instructs the plane setting operation, the CPU 58 controls the program according to the program. Alternatively, it may be realized by an operator switching ON and OFF of the valves 55 and 56 with a switch or the like.

Next, after the planarizing operation is completed, the substrate B
Is mounted on the stage surface 62, and the bonding head 26 to which the semiconductor chip C is sucked moves to the mounting position by the rotation of the head holder 31.

Next, the head unit 6 is lowered by the rotation of the elevating motor 11, and the semiconductor chip C is mounted on the substrate B.

[0039]

As described above, according to the present invention, since the head holding portion sucks the bonding head while the bonding head is fixed by sucking the stage surface, the angular position can be surely prevented from being shifted by a shock. A flat surface can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing a head unit.

FIG. 2 is a side view of a die bonder provided with a head unit.

FIG. 3 is a side view showing a head unit.

FIG. 4 is a control block diagram of a die bonder.

[Explanation of symbols]

 Reference Signs List 3 Elevating device (elevating means) 6 Head part 26 Bonding head 28 Head holding part 38 Profile surface (holding angle changing mechanism) 40 Engagement surface (holding angle changing mechanism) 41 Hole (holding angle changing mechanism) 43 Hole (holding) Angle changing mechanism) 44 Support arm (holding angle changing mechanism) 45 Support rod (holding angle changing mechanism) 46 Tension spring (holding angle changing mechanism) 53 Chip suction surface 55 Head suction valve 56 Chip suction valve 58 CPU (control means) ) 62 Stage surface

Claims (4)

[Claims] A semiconductor chip to which a bonding head is vacuum-sucked is bonded to a substrate; a head holding section for holding and fixing the bonding head by vacuum suction; and a bonding head when the vacuum suction of the head holding section is released. In a bonding apparatus having a holding angle changing mechanism capable of changing a holding angle position with respect to a head holding unit, a stage surface serving as a reference for performing flattening by contacting a suction surface of a semiconductor chip of the bonding head; Elevating means for elevating the head holding unit,
A chip suction valve that opens and closes for vacuum suction and release of the semiconductor chip by the bonding head, a head suction valve that opens and closes for vacuum suction of the bonding head by the head holding unit and release thereof, and the elevating means When the head holding unit is lowered, the chip suction valve is opened and vacuum suction is performed before the bonding head comes into contact with the stage surface, and then the head holding unit vacuum suctions the bonding head. A bonding apparatus comprising a suction valve and a control means for controlling a head suction valve. 2. The apparatus according to claim 1, wherein the holding angle changing mechanism is configured to move relatively along the surface formed on the head holding portion or the bonding head, and the holding portion is capable of moving the bonding head under vacuum. 2. The bonding apparatus according to claim 1, further comprising an engaging portion that engages with the profile surface and angularly positions the bonding head on the head holding portion. 3. The bonding apparatus according to claim 2, wherein the profile surface is a part of a spherical surface. 4. When the vacuum suction of the head holding unit is released, the suction surface of the bonding head is brought into contact with a reference stage surface, and the holding angle position with respect to the head holding unit is changed.
In a bonding head flattening method of holding a bonding head by vacuum suction again with a head holding unit and flattening the bonding head, a head lowering step of lowering the head holding unit, and vacuum-adsorbing a stage surface to the bonding head. A method for flattening a bonding head, comprising: a stage surface suctioning step; and a head holding step of vacuum-sucking the bonding head to a head holding section and holding the bonding head at an angular position set to be flat.