JPH0750717B2 - Die bonder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a die bonding apparatus for die bonding an electronic component such as a semiconductor chip to a lead frame.

(Prior Art) Generally, a semiconductor device is generally assembled through the following steps. In each of these steps, a brazing material such as tin-containing solder is placed on a predetermined portion of the lead frame, which is usually called a die pad, on which a semiconductor chip is to be placed, and the semiconductor chip is heated and melted to a predetermined temperature. Die-bonding step of brazing and fixing, wire-bonding step of connecting the upper surface electrode of the semiconductor chip and the lead frame with a thin metal wire such as gold wire, resin sealing step of sealing the periphery including the semiconductor chip, etc. It consists of

By the way, in the recent semiconductor device manufacturing process, especially in the die-bonding process, the production is being replaced by an automatic machine in order to improve productivity, but the lead frame itself is further elongated and further A large number of semiconductor devices have been manufactured from one lead frame, but these are further arranged in one row in which two die pads are arranged in two rows. By doing so, it is possible to provide semiconductor devices twice as many as those obtained from the conventional lead frame structure.

FIG. 11 is a perspective view of a main part of such a lead frame. As shown in FIG. 11, in one lead frame 1, two rows of die pad portions 1a are arranged in the longitudinal direction of the lead frame 1 in the width direction of the lead frame 1. Reference numeral 1b is a wire bond portion provided for a plurality of die pad portions 1a, 1c is an external lead portion for a plurality of wires, and 1d is a belt-shaped connecting portion on both sides.

As a conventional die bonding apparatus for the lead frame 1 in which the die pad portions 1a as shown in FIG. 11 are provided in two rows, there is one disclosed in Japanese Patent Publication No. 63-25703.

A conventional die bonder according to the above publication is shown in FIG. 12 (however, FIG. 5 in the above publication). For convenience of explanation, the reference numerals of the parts and portions shown in FIG. 12 correspond to the reference numerals of the parts and the components in Japanese Patent Publication No. 63-25703.

In this conventional die-bonding apparatus, 2 is a semiconductor chip, 6 is a pair of linear motion bearings, 7 is a pair of support members fixed to the frame body 30 shown by chain lines and holding each bearing 6, and 8 Is a drive fitting fixed to the sliding shaft guide shaft 31. A support shaft 9 is fixed to the lower portion of the drive fitting 8, and the rolling element 10 is supported on the support shaft 9. A plate cam 11 is rotatably fixed to a cam shaft 12 supported by the frame body 30. The cam shaft 12 is adapted to be intermittently rotated by a drive device (not shown) such as an electric motor. Reference numeral 13 denotes a swing arm that is rotatably supported around a support pin 14 fixed to the frame body 30. The tip of the swing arm 13 is bifurcated, and the rolling element 10 is sandwiched and engaged with the forked tip. 15
Is a cam follower rotatably supported on the intermediate portion of the swing arm 13 by a support pin 16, which is in contact with the outer periphery of the plate cam 11 and transmits the rotary motion to the swing arm 13. 17 is mounted between the frame body 30 and the swing arm 13, and the swing arm 13 is attached to the plate cam 11
It is a tension spring that pulls to the side. A suction head 18 supports a suction needle 19 having a thin through hole so as to be vertically movable. The suction needle 19 is connected to a suction pipe 20, and the semiconductor chip 2 can be suction-held by being vacuum-sucked by a vacuum pump (not shown). Reference numeral 21 is a pneumatic cylinder fixed to a suction head 18, and a suction member 19 is connected by a connecting member 23 attached to a piston rod 22 and moved up and down.

Reference numeral 30 is the frame of the die bonding apparatus, 31 is a hollow slide guide shaft supported by the bearing 6 and moved forward and backward by a swing arm 13 for a predetermined distance, and 32 is supported by the slide guide shaft 31 so as to be movable in the front-rear direction. Further, the suction shaft 18 is fixed to the front end of the support shaft and is constantly pulled by the tension spring 33 in the backward direction with respect to the sliding guide shaft 13.

34 is a support frame attached to the rear end of the sliding guide shaft 31, 35 is a mounting bracket fixed to the rear end of the support shaft 32, 36 is a receiving rod fixed vertically to the mounting bracket 35, and a cam follower is attached to the upper end. 37 is installed. 38 and 39 are a pair of racks attached to both upper and rear sides of the frame body 30, and 40 is a rack 38
One pinion that rolls up and is rotated is fitted on the outer circumference of the one-way clutch 41. 42 is supported by a support frame 34 via a bearing (not shown), and has a one-way clutch at one end.
41 is fixed and the spur gear 43 is fixed to the other end of the transmission shaft, 44
Is the other pinion that rolls and rotates on the rack 39, and is fitted on the outer periphery of the one-way clutch 45. 46 is a support frame
The transmission shaft is supported by a bearing 34 (not shown) on one side, and has a one-way clutch 45 fixed on one end. A spur gear 47 with the same number of teeth that meshes with the spur gear 43 is fixed on the other end.
48 is stuck. 49 is a bearing on the support frame 34 (not shown)
The cam shaft 50 is fixed vertically via the worm gear 50 and is fixed to the worm 48, and the worm gear 50 is fixed to the worm 48.The plate cam 51 is fixed to the upper end of the cam shaft 49, and its outer periphery is brought into contact with the cam follower 37. The support shaft 32 is moved relative to the slide guide shaft 31 by a predetermined distance in the axial direction.

Regarding the operation of the conventional die bonding apparatus having such a configuration, the above publication is referred to, and the description thereof is omitted in this specification.

(Problems to be Solved by the Invention) By the way, the following problems are pointed out in such a conventional die bonder. First, a support frame 34 is provided in the rear portion of the slide guide shaft 31, and various pinion gears, worm gears, etc. are incorporated in the support frame 34, so that the support frame 34 has a certain amount or more. Since the strength is required, the support frame 34 including all the built-in parts has a weighted structure of, for example, 800 to 1,000 g, which is a great obstacle to shortening the cycle time of the die bonding process of the entire device. .

More specifically, when rotating the plate cam 11 at high speed,
Weighted suction head 18, sliding guide shaft 31, and support frame 34
The whole is to be moved by the swing amou 13, but for that reason the tension force of the tension spring 17 is strengthened so that the plate cam 11 and the cam follower 15 attached to the swing amou 13 do not come out of engagement. However, if the pulling force is increased above a certain level, the driving torque of the plate cam 11 will be lost by the force of the tension spring 17 and the plate cam 11 will not be able to rotate stably. There is. Therefore, it is difficult to reduce the cycle time of the die bonding process.

Secondly, due to the engagement of the racks 38, 39 and the pinions 40, 44, as the moving speed of the support frame 34 increases, the racks 38, 3
As a result of the upward thrust on the pinion from the tooth flank shape of 9 becoming stronger, the force that lifts it upwards acts on the support frame 34, and when the pinion moves to the tooth flank of the next rack,
Its upward thrust decreases. Then, if such repetition occurs within a short time, the support frame 34 moves up and down, and vibration occurs. Such vibrations deteriorate the accuracy of die bonding.

The present invention has been made in view of the above problems, and an object of the present invention is to shorten the cycle time of the die bonding process and improve its accuracy.

(Means for Solving the Problems) In order to achieve such an object, a die bonding apparatus according to the present invention includes a suction head that supports a suction needle so as to be vertically movable, and a contact plate at the other end. A support shaft movably in the axial direction and driven by a first drive means to move a predetermined amount, and a suction head side of the support shaft is placed on a lead frame having a plurality of die pads for mounting electronic components. A sliding guide shaft for guiding, a block fixed to the sliding guide shaft, a vertical movement rail that is moved up and down by being driven by a second drive means, and is rotatably fixed to the block and also to a contact plate. The first rolling element that engages and the second rolling element that engages with the vertical movement rail are arranged at a predetermined link ratio with respect to the center of rotation, and the second rolling element moves up and down together with the vertical movement rail. By moving And a plate that rotates in accordance with the rotation of the support plate. The plate causes the support shaft together with the contact plate to be displaced in the axial direction relative to the slide guide shaft, and the suction head side of the support shaft is the lead frame. When guided upward, the suction head is guided by the lead frame to the first die pad portion or the second die pad portion which are arranged in parallel in the axial direction of the support shaft according to the relative displacement amount.

(Operation) According to the above configuration, when the slide guide shaft is moved by being driven by the first drive means, the suction head at one end of the support shaft moves in the moving direction of the slide guide shaft when the slide guide shaft moves. It is located on the electronic component or the lead frame accordingly.

When the suction head is on the electronic component, the suction needle is lowered from that position, and the suction needle suctions the electronic component and then raises the suction needle. When the suction needle is on the lead frame, the suction needle is lowered from that position and the electronic component sucked by the suction needle is placed on the die pad portion of the lead frame.

In this case, by driving the vertical moving rail by the second driving means, the suction head is positioned on one die pad portion of the lead frame via each rolling element of the plate and the contact plate at the other end of the support shaft, and then, Similarly, the vertical driving rail is driven by the second driving means to position the suction head on the other die pad portion of the lead frame in the same manner as described above.

That is, the first driving means moves the suction head onto the pedestal of the semiconductor chip and the lead frame, and the second driving means moves the vertical movement rail up and down by a displacement amount corresponding to each die pad portion. At the same time, the vertical displacement is transmitted to the second rolling element, and the contact plate is moved by the first rolling element by an amount corresponding to the displacement.
By transmitting the displacement amount of the contact plate as the displacement amount of the other suction head of the support shaft, the suction head is arranged in parallel with the axial direction of the support shaft in the lead frame, and the first die pad portion and the second die pad portion are provided. The electronic components can be made to face each other so that the electronic components can be die-bonded to the respective die pad portions.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of a die-bonding apparatus according to an embodiment of the present invention shown in an assembled state, and FIG. 2 is a perspective view after partially assembling in order to explain the main structural portion of the apparatus in more detail. It is a perspective view showing the arrangement of each component including the,
FIG. 3 is a left side view of the main part of the apparatus shown in FIG. In these figures, the same reference numerals as those shown in FIG. 11 and FIG. 12 according to the conventional example indicate the same parts, parts and the like indicated by the reference numerals, unless otherwise specified. The parts and parts according to the present embodiment have the same configurations as the present embodiment and the conventional example, and the description of the parts and parts with the same reference numerals is omitted.

In this embodiment, the configuration different from the conventional example is as follows. That is, in the die bonding apparatus of this embodiment,
An L-shaped block 81 is fixed to the rear end of the sliding guide shaft 31. A support shaft 32 is passed through the L-shaped block 81, and a contact plate 80 is fixed to the rear end of the support shaft 32. The center of rotation of the L-shaped plate 82 is rotatably attached to the tip of the L-shaped block 81 via a collar 83 and a bolt 84. The L-shaped plate 82 is provided with an arm portion extending in an L-shape from the center of rotation thereof, and a radial bearing 86 as a first rolling element that engages with the contact plate 80 is provided on the upper arm portion of the collar 85. A radial bearing 89 as a second rolling element is attached to the lower arm portion of the L-shaped plate 82 via the collar 88 and the bolt 90 so as to engage with the upper surface of the vertically moving rail 69. It is installed.

On the other hand, first sliding guide shaft 31 is moved back and forth in the axial direction.
A timing pulley 61 is fixed to a cam shaft 12 that rotates a plate cam 11 that constitutes the cam device. And this camshaft
The rotational force of 12 is the timing pulley 61 and the timing belt.
It is adapted to be transmitted to the cam shaft 63 via the timing pulley 64 and the timing pulley 64. The tooth number ratio of the timing pulley 61 and the timing pulley 64 is 1: 2, and the cam shaft 63 is set to make a half rotation when the cam shaft 12 makes one rotation. The cam shaft 63 is attached to the frame body 30 on the side surface of the die bonding apparatus via a bearing unit (not shown). An index cam 65 as a second cam device is fixed to the cam shaft 63, and a radial bearing 66 is attached to a bolt 68 so as to engage with the cam surface (outer peripheral portion) of the index cam 65.
It is attached to the mounting plate 67 via. Mounting plate 67 is 2
It is attached to the vertical movement rail 69 by a bolt 70. The vertical movement rail 69 is provided so as to be vertically movable relative to the frame body 30 by a pair of ball rows 71 and a pair of V-shaped blocks 72.

Next, the operation will be described with reference to FIGS. 4 to 10.

When the cam shaft 12 is rotated by an electric motor (not shown),
The plate cam 11 fixed to the cam shaft is rotated in the direction of arrow A in FIG. Then, the swing arm 13 is swung about the support pin 14 in the direction of the arrow B in FIG. 1 along the cam displacement amount of the outer peripheral portion of the plate cam 11, and the tip of the swing arm 13 is moved. The rolling element 10 that is engaged with is moved. As a result, the slide guide shaft 31 is moved to the semiconductor chip 1 side in the direction of arrow C in FIG. 4 to reach the position shown in FIG.

In this case, since the suction head 18 is connected to the tip of the slide guide shaft 31 by the tension spring 33, the suction head 18 can also be moved by the same size as the above-mentioned movement amount of the slide guide shaft 13. Become.

On the other hand, when the cam shaft 12 is rotated as described above, the timing pulley 61 fixed to the cam shaft 12 is rotated, and thereby the timing pulley 64 is also rotated via the timing belt 62. Since the timing pulley 64 rotates the cam shaft 63, the index cam 65 fixed coaxially with the cam shaft 63 is rotated. As a result, the radial bearing 66 and the vertical movement rail 69 are moved along the cam displacement amount of the outer peripheral portion of the index cam 65.
As a result, it is vertically moved to the state shown in FIG.

At this time, the radial bearing 89 engaged with the flat portion on the vertical movement rail 69 constitutes a link mechanism by the L-shaped plate 82 and the radial bearing 86, and the radial bearing 89 is moved by the vertical movement rail 69. When rotated upward, the link ratio, that is, the length l from the support shaft (hole through which the bolt 84 passes) of the L-shaped plate 82 to the radial bearing 86.
And the length l ′ from the same support shaft to the radial bearing 89 are provided as the same length in this embodiment,
In this case, the link ratio is 1: 1 and the contact plate 80 is pushed rightward in FIG. 4 by the same displacement amount as the displacement amount of the vertical movement rail 69. As a result, the entire suction head 18 whose one end is connected to the other end of the support shaft 32 which is connected to the contact plate 80 is moved from the state of FIG. 4 to the state of FIG. When the suction head 18 is moved from the position shown in FIG. 5 to the position shown in FIG. 4, the operation is the reverse of the above.

The above operation is a basic operation for moving the suction head 18 onto the semiconductor chip 1 placed on the pedestal 24 and the lead frame 2.

Next, the actual die bonding operation will be described based on the above basic operation. First, the suction head 18
As shown in the figure, air pressure is applied to the pneumatic cylinder 21 to lower the suction needle 19 in a state in which the suction needle 19 is positioned directly above the semiconductor chip 2 placed on the pedestal 24. Then, the inside of the suction tube 20 is evacuated (vacuum), so that the semiconductor chip 2 is sucked by the suction needle 19.
To vacuum and fix. After the fixing, by releasing the air pressure applied to the pneumatic cylinder 21, the suction needle 19 is raised by a compression spring (not shown) provided inside the pneumatic cylinder 21 and stops at the top dead center. . Under this condition, voltage is next applied to the motor and the cam shaft
Drives 12 1/2 turn (180 °), plate cam 11, swing arm
The sliding guide shaft 31 is moved by 13 or the like onto the lead frame 1 as shown in FIG.

The behavior of the index cam 65 at this time will be described with reference to FIG. First, when the circumference of the index cam 65 is divided into four equal parts, AA to DD, as shown in the figure, in the state shown in FIG.
It is located in the AA category. Next, when the index cam 65 makes a quarter turn from this state, the radial bearing 66 is positioned in the BB section of the index cam 65. At this time,
In the index cam 65 shown in FIG. 10, the AA section and the CC section are the same circle portion with the same radius Z1 from the center of rotation, the BB section has the radius Y1 in the figure, and the DD section shows radius
The radial bearing shown in Fig. 5 has X1 and has the difference Y1-Z1 as the displacement amount α from the relationship of X1 <Z1 <Y1.
89 is lifted by the dimension α by the quarter turn of the index cam 65. Then, since the vertical movement rail 69 is also raised by the dimension α, the radial bearing 86 engaged with the vertical movement rail 69 is also rotated by the dimension α. As a result, the contact plate 80 engaged with the radial bearing 86 is moved to the right in the figure. In this case, since the arm lengths from the center of the L-shaped plate 82 to the radial bearings 89 and 86 are the same, the moving amount of the contact plate 80 is the same as the moving amount of the vertical moving rail 69 and the suction head 18 is moved. Is added to the amount moved by the plate cam 11 by the α dimension, and is moved by the YZ dimension as a whole.

In this state, the semiconductor chip 2 is positioned directly above one die pad portion of the lead frame 1. From this position, the semiconductor chip 2 is moved to the pneumatic cylinder.
It is moved down by applying compressed air to 21 and placed on the die pad portion of the lead frame 1. After the placement, the vacuum in the suction tube 20 is released, so that the connection between the semiconductor chip 2 and the suction needle 19 is released. Then, in this state, the semiconductor chip 2 is die-bonded to the die pad portion of the lead frame 1.

Next, the compressed air of the pneumatic cylinder 21 is released to raise the suction needle 19. The pedestal 24 accommodating the semiconductor chip 2 during this operation is moved in the direction of arrow E in the figure by an XY table (not shown), and the next semiconductor chip 2 is moved to the suction point. . From the state shown in FIG.
The suction head 18 moves to the 6th position when 12 is rotated 1/2 turn.
It is retracted to the position shown in the figure.

In the meantime, the index cam 65 is also rotated 1/4 turn to position the radial bearing 66 in the CC section range as shown in FIG. In other words,
The vertical movement rail 69 is lowered by the amount α.
In FIG. 6, when a new semiconductor chip 2 is sucked and fixed by the suction needle 19, the cam shaft 12 is rotated again by 1/2, and the suction head 18 is advanced right above the second die pad portion. . At this time, the index cam 65 is also 1 /
As it is rotated 4 times, it will be moved to DD section in FIG. That is, assuming that the difference between Z1 and X1 is β, the vertical movement rail 69 can be lowered this time by the amount β due to the relationship of X1 <Z1 <Y1. Therefore, the β dimension is subtracted from the movement amount by the plate cam 11, and the suction head 18 is moved by the X2 dimension as a whole. This state is shown in FIG. Next, the pneumatic cylinder 21 is lowered (the suction needle 19 is also lowered), and the semiconductor chip 20 is die-bonded to the remaining die pad portion. Then, after that, the pneumatic cylinder 21 is raised (the suction needle 19 is also raised),
This means that a series of die bond operations has been completed.

Here, if the movement amount of the suction head 18 is arranged once again, the displacement amount of the plate cam 11 is always constant.
For a lead frame having two rows of die pad portions as shown in the figure, the suction head 18 must be moved relative to the displacement of the plate cam 11. Therefore, the sixth
The dimension Y2-X2 between the die pads shown in the figure is the amount of displacement of the index cam that corresponds to this (Fig. 10).
It should be the same as Y2-X2.

Since there are various lead frames in use, a split cam may be used as shown in FIGS. 8 and 9 to facilitate replacement of the index cam. If the index cam 65 in the figure has a structure in which the cam 65a and the cam 65b are connected by two bolts, there is an advantage that the replacement work of the index cam 65 can be completed in a short time (about 1 minute).

(Effects of the Invention) As is apparent from the above description, according to the present invention,
Since the mechanism for moving the suction head has a simple structure,
The overall weight is significantly lighter than the conventional example, and it is possible to significantly shorten the time required for the suction head to move back and forth, resulting in a significant increase in production volume. It will be possible.

Further, according to the present invention, since the structure of the gear train such as the rack and the pinion, which has a bad influence on the accuracy of the die bond due to the vibration of the supporting frame as in the conventional example, is not used, the accuracy can be improved. Became.

[Brief description of drawings]

1 to 10 relate to a die bonding apparatus of an embodiment of the present invention, and FIG. 1 is a perspective view of the apparatus of the same embodiment of the present invention, and FIG.
FIG. 3 is an exploded perspective view thereof, FIG. 3 is a left side view of the apparatus of the same embodiment, FIGS. 4 to 7 are side views of main parts used for explaining the operation in the die bonding process, and FIGS. 8 and 9 are indexes. A perspective view and a plan view showing a modified example of the cam,
Figure 10 is a plan view of the index cam. FIG. 11 is a perspective view of a lead frame, and FIG. 12 is a perspective view of a conventional die bonder. 1 ... Lead frame, 1a ... Die pad, 2 ... Semiconductor chip, 11 ... Plate cam, 13 ... Swing arm, 15 ...
Cam follower, 18 ... Suction head, 19 ... Suction needle, 21 ...
… Pneumatic cylinder, 31 …… Sliding guide shaft, 32 …… Support shaft,
33 …… tension spring, 61 …… timing pulley, 62 …… timing belt, 63 …… cam shaft, 64 …… timing pulley, 65 …… index cam, 66 …… radial bearing, 69 …… vertical movement rail, 80 …… Contact plate, 81 …… L-shaped block, 82 …… L-shaped plate, 86 …… Radial bearing, 89 …… Radial bearing. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A support shaft movably in the axial direction, which has a suction head that supports a suction needle so that it can move up and down, and a support shaft that has a contact plate at the other end, and is driven by a first drive means. And move a predetermined amount, and the suction head side of the support shaft,
A slide guide shaft for guiding onto a lead frame having a plurality of die pads for mounting electronic parts, a block fixed to the slide guide shaft, and a vertical movement driven by a second drive means to move up and down. A rail, a first rolling element that is rotatably fixed to the block, and that engages with the contact plate, and a second rolling element that engages with the vertical movement rail with respect to the center of rotation thereof. It is arranged with a predetermined link ratio, and the second rail and the second moving rail are arranged together.
A plate that rotates when the rolling element moves up and down, the plate, together with the contact plate that engages with the first rolling element by the rotation, the supporting shaft, the sliding guide shaft, Relative to the axial direction, and when the suction head side of the support shaft is guided onto the lead frame, the suction head is supported on the lead frame by the lead frame according to the relative displacement amount of the support shaft. A die bonder characterized in that it is guided to a first die pad portion or a second die pad portion which are arranged in parallel in the axial direction.