JPH03215952A - Inner lead bonding method and device - Google Patents

Abstract

PURPOSE:To enable a bonding tool to be easily controlled in position and to prevent a defective semiconductor chip from occurring by a method wherein a bonding tool state detecting means which detects that the bonding tool reaches to a bonding position and makes a semiconductor chip bear against inner leads is provided. CONSTITUTION:A bonding member 7 is provided with a bonding tool 8 which pressure-joins a semiconductor chip 3 to inner leads 6 and descends or ascends freely in conjunction with the bonding tool. A drive means 31 directly drives the bonding member 7 to displace. A bonding tool position detecting means 37 detects the position of the bonding tool 8 basing on the quantity of drive of the drive means 31. A bonding tool state detecting means 38 detects that the bonding tool 8 reaches to a bonding position and makes a semiconductor chip bear against inner leads. By this setup, a bonding tool can be easily controlled in position and a semiconductor chip can be protected against defects.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Field of Application) The present invention relates to an inner lead bonding device and an inner lead bonding device for thermocompression bonding an inner lead of a wiring pattern and an electrode bump of a semiconductor chip using a bonding tool, for example. This invention relates to an inner lead bonding method.

(Prior Art) Generally, as a manufacturing apparatus for semiconductor devices, as shown in FIGS.
An inner lead bonding apparatus 1 as shown in the figure is known. That is, this inner lead bonding device 1 includes electrode bumps (hereinafter referred to as bumps) 4 protruding from a semiconductor chip 3 placed on a mounting table 2 and an inner lead bonding device formed on a carrier tape 5. Lead 6...
After the bonding tool 8 is positioned at the lower end of the bonding member 7 and heated to a high temperature, the bonding tool 8 is lowered.

Then, the inner lead bonding apparatus 1 brings the bonding tool 8 into contact with the inner leads 6 . . . and presses the inner leads 6 . And inner lead 6.
... to bump 4..., and inner lead 6.
... and bump 4... are connected together. Further, the inner lead bonding device 1 performs the above-described bonding operation while intermittently running the carrier tape 5,
Semiconductor chips 3 are sequentially mounted on carrier tape 5.

Further, such an inner lead bonding apparatus 1 is provided with a bonding tool 8 via a motion conversion mechanism 9 as shown in, for example, Japanese Patent Application No. 78744/1983.
There is something that makes it go up and down.

That is, as shown in FIG. 5, this type of inner lead bonding apparatus 1 includes a bonding tool 8 which is supported by a tool holder 10 and a tension spring 11 so as to be movable up and down above the mounting table 2. There is. Further, a servo motor 5 having a disc-shaped cam 14 attached to its output shaft is arranged on the base 13 above the X-Y drive unit 12 that supports the tool holding unit 10, and this cam 14 and the It has a structure in which the Dinguru 8 is connected via the motion conversion mechanism 9 mentioned above.

Specifically, the motion conversion mechanism 9 includes a first swing lever 17 to which a cam follower 16 that is combined with the cam 14 is attached adjacent to the output shaft side of the servo motor 515; A crank-shaped second swing lever 18 is rotatably supported on the action point side of the first swing lever 17.

An air cylinder 19 serving as a damper means for adjusting tool movement is interposed between the force side of the second swing lever 18 and the force side of the first swing lever 17. When the cam 14 rotates following the operation of the sabot motor 5, the movement causes the first and second swing levers 1 to rotate.
7 and 18, the bonding tool 8 is lowered via the pressing rod 20, and the pressing portion at the tip presses the inner leads 6 into the bumps 4 of the semiconductor chip 3. Press down.

Thereafter, the swing lever 17 is pushed up by a predetermined amount, and the rod of the air cylinder 9 is sunk by that amount, and the servo motor 5 is stopped. Then, the inner lead 6 is pressed with a force corresponding to the pressure inside the air cylinder 9.

6 Here, 21 is a guide body that supports the press rod 20 in a vertically movable manner, and 22 is a column that supports the first swing lever 17.

Furthermore, this inner lead bonding device 1 further includes an inner lead 6 pushed down by a bonding tool 8.
It has a gap sensor 23 that detects when the bumps 4 of the semiconductor chip 3 come into contact with the bumps 4 of the semiconductor chip 3. Then, the rotational speed of the servo motor 5 is controlled based on the detection signal of the gap sensor 23, and after a certain period of time has elapsed since the inner lead 6 came into contact with the bump 4... The suppression process using the bonding tool 8 has been completed.

Moreover, such a bonding method, that is, T A B
(Tape Auto+ated Bonding)
Now, the inner lead 6, which is made of tinned copper...
・It is common practice to diffuse gold and gold bumps into a gold-soot eutectic bond, but in recent years, consideration has been given to using solder bumps instead of gold bumps to reduce material costs. has been done.

(Problems to be Solved by the Invention) By the way, in the conventional inner lead bonding apparatus 1 as described above, the driving force of the servo motor 15 is transmitted to the bonding claw 8 via the motion conversion mechanism 9.
The device configuration was complex and had a large number of parts. Furthermore, by interposing the motion conversion mechanism 9 between the servo motor 15 and the bonding tool 8, the position of the bonding tool 18 cannot be controlled in the pressed state.

Further, when solder bumps are used, the solder bumps are melted and bonded to the inner leads 6, which may cause defects in the semiconductor chip and reduce reliability. In other words, when using solder bumps, as shown in FIG. 7(a), pressure is applied by the bonding tool 8 to connect the inner leads 6 to the solder bumps 4...
If the inner leads 6 continue to be pressurized after being brought into contact with the solder bumps 4, the solder bumps 4 will melt over time.

Even when the servo motor 15 stops, the action of the air cylinder 19 causes the solder bumps 4 to melt and collapse as shown in FIG. ... goes down. Then, the solder bumps 4 are crushed too much, and the inner leads 6 (and the bonding tool 8) are lowered excessively, and the inner leads 6 directly contact the semiconductor chip 3, causing the semiconductor chip 3 defects will occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inner lead bonding device that can control the position and pressure of a bonding tool with a simple configuration, and that is highly reliable without causing defects in semiconductor chips.

[Structure of the Invention] (Means and Effects for Solving the Problems) To achieve the above object, the present invention provides an inner lead bonding device for compressing a semiconductor chip and an inner lead of a wiring pattern. A bonding member that has a bonding tool that makes pressure contact with the lead and can be moved up and down together with the bonding tool, a drive means that directly drives and displaces this bonding member, and a bonding tool based on the amount of drive of this drive means. bonding tool position detection means for detecting the position of the bonding tool, and bonding tool state detection means for detecting that the bonding tool has reached the bonding position and brought the semiconductor chip and the inner lead into contact.

Further, an electric signal is output to the drive means based on the outputs of the bonding tool position detection means and the bonding tool state detection means, and the magnitude of the electric signal output to the drive means is changed to adjust the pressing force of the bonding tool. A control section was provided.

The present invention also includes a bonding member that has a bonding tool that presses the semiconductor chip and the inner lead and can be moved up and down integrally with the bonding tool, a drive means that directly drives and displaces the bonding member, and a drive amount of the drive means. bonding tool position detection means for detecting the position of the bonding tool based on the bonding tool position, and bonding tool state detection means for detecting when the bonding tool has reached the bonding position and brought the semiconductor chip and the inner lead into contact. and a control section that controls the amount of displacement of the bonding tool based on the outputs of the bonding tool position detection means and the bonding tool state detection means.

In addition, in an inner lead bonding method in which the inner leads of a bump wiring pattern for electrodes protruding from a semiconductor chip are bonded by thermocompression, a bonding vine provided on a bonding member that can be raised and lowered is made to reach the bonding surface to connect the inner leads to electrodes. A first step of bringing pressure into contact with the bump;
A second step of displacing the bonding tool as the electrode bump melts and stopping the bonding tool when the bonding tool reaches a predetermined position was included.

By doing so, the present invention enables the bonding tool to be driven efficiently, and furthermore, it is possible to prevent the occurrence of defects in semiconductor chips and improve reliability.

11 (Embodiment) Hereinafter, main parts of an embodiment of the present invention will be explained based on FIGS. 1 to 3. Components that are the same as those described in the prior art section are given the same numerals and their explanations will be omitted.

FIG. 1 shows an embodiment of the present invention, and 1 in the figure shows T.
A B (Tape Automated Bondi
ng) is shown.

This inner lead bonding apparatus 1 holds a bonding member 7 in an X-Y drive part 12 via a tool holding part 10 so as to be able to move forward and backward in the vertical direction, and a semiconductor chip 3 is mounted on the bonding part 7. It is located almost directly above the mounting table 2. Furthermore, the inner lead bonding apparatus 1 has a base 13 above the X-Y drive section 12, and a servo motor 31 as a drive means is held on this base 13 via a motor holding bracket 32. are doing.

Further, the bonding member 7 has a press rod 20 located at its upper end supported by a guide member 33 of a bracket 32 so as to be able to move forward and backward in the vertical direction. Furthermore, the bonding member 7 has a nut 34 integrally coupled to the outer peripheral surface of the press rod 20, and this nut 1, 34 is screwed into a ball screw 35 protruding downward from the servo motor 31. The bonding member 7 moves up and down as the ball screw 35 rotates, vertically displacing the bonding tool 8 coaxially disposed at the lower end.

Here, reference numeral 11 in the figure indicates a tension spring whose both ends are connected to the tool holding part 10 and the bonding member, respectively.

Further, the bonding member 7 is driven by the servo motor 31 and lowered to bring the head surface 36 of the bonding head 8a into contact with the inner leads 6 that have been supplied above the mounting table 2 and stopped, and furthermore, this inner lead 6.
... are pressed down together with the carrier tape 5 to bring them into thermal conductive contact with the corresponding electrode bumps (hereinafter referred to as bumps) 4 of the semiconductor chip 3. Then, the inner leads 6 and the bumps 4 are connected together by the pressure and heat of the heated bonding head 8a, which has become high in temperature 13, and the semiconductor chip 3 is attached to the carrier tape 4. do.

Further, the bonding member 7 is attached to a servo motor 31 and detects the position of the bonding tool 8 by a position detector 37 as a bonding tool position detecting means that detects the position of the bonding tool 8 by using the amount of rotation of a ball screw 35 or the like. It is now detected.

Further, the bonding member 7 is attached to the outer peripheral surface of the pressing rod 20.
A strain gauge 38 is attached as a bonding tool state detection means, and the strain gauge 38 detects whether or not the bonding tool 8 is bringing the inner lead 5 into contact with the bump 3. It has become.

That is, as shown in FIG. 2, the position detector 37 knows the position of the bonding tool 8 from the drive amount of the servo motor 31, and sends a feedback signal 39 corresponding to the position of the bonding tool 8 to the controller 40 and the position speed. converter 4
Output to 1 and 1. Then, the control unit 40 outputs a speed command signal 43 to the converter 42 by using the microcomputer with reference to the feedback signal 39 from the position detector 37.

Further, the comparator 42 compares the speed command signal 43 from the control section 40 and the speed feedback signal 44 from the position/speed converter 41, and sends the current command signal 45 to the amplifier 4.
Send to 6. The current 47 amplified by the amplifier 46 is then sent to the servo motor 31.

Here, the control section 40 controls the output 4 of the strain gauge 38.
It is now possible to receive a rating of 8.

Next, the operation of the inner lead bonding apparatus 1 having the above-described structure will be explained based on FIG. 3.

(a) in FIG. 3 shows the lifting and lowering movement of the bonding tool 8 during approximately one cycle of bonding work. That is, the bonding tool 8 is driven by the servo motor 31 from a state where it is stopped above the mounting table 2 and starts descending toward the inner lead 6 .
At the beginning of the descent, the aircraft moved at high speed as shown by A.

And Bonding Girl 8 is Inner Lead 6...
When the head surface 36 is brought into contact with the bump 4..., in the period from the plane where the head surface 36 is located, that is, a portion somewhat in front of the bonding surface, until it reaches the bonding surface,
As shown in , it descends with a lower uniform velocity than before. Then, when the bonding tool 8 reaches the bonding surface, the inner leads 6... and the bumps 3
... are compressed in the axial direction together with the press rod 20 by contacting with each other.

Here, the dashed line C in FIG. 3 indicates the position of the bonding surface.

When the press rod 20 is compressed, the output signal 48 of the strain gauge 38 changes as shown by D in FIG. 3(b). The control unit 40, which receives the output signal 48 of the strain gauge 38, senses that the bonding tool 8 has reached the bonding surface based on a change in the output signal 48, and outputs a predetermined pressure command signal. .

16 Then, the pressurization command signal issued from the control unit 40 is amplified by the amplifier 46 similarly to the speed command signal 43, and as shown in (C) in FIG. 3, the pressurization command signal is amplified. A current having a value corresponding to the current flows through the servo motor 31.

Then, the servo motor 31 generates a torque according to the input current, and operates to pressurize the bonding tool 8, the inner lid 6, etc. via the ball screw 35, nut 34, and press rod 20. let

Furthermore, when solder is used for the bumps 4 of the semiconductor chip 3, when the solder bumps 4 come into contact with the bonding tool 8 via the inner leads 5, the bonding tool 8 is The solder bumps 4 melt due to the pressure and heat. Then, when the solder bumps 4... begin to melt, the bonding tool 8 gradually descends as the solder bumps 4... melt.

The control section 40 constantly monitors the position of the bonding tool 8 by receiving the position feedback signal 39, and when the bonding tool 8 descends by a predetermined distance g from the bonding surface 17, A pressurization stop signal is output to the servo motor 31 instead of the pressurization command signal.

Then, the control unit 40 controls the bonding tool 8 when the bonding tool 8 reaches the bonding surface, or when the bonding tool 8 reaches the bonding surface.
After holding the bonding tool 8 at that position until a predetermined time t has elapsed from the time when the bonding tool 8 has descended from the bonding surface by a predetermined distance ρ, the bonding tool 8 is held at a high speed as shown by E in (a) of FIG. Raise at the same speed as at the beginning of the descent.

Such an inner lead bonding device 1 drives the bonding member 7 by directly transmitting the drive amount of the servo motor 31 from the ball screw 35 to the nut 35, so the structure can be simplified and the parts The number can be reduced.

In addition, the position of the bonding tool 8 is monitored even after the bonding tool 8 reaches the bonding surface, and the amount of displacement of the bonding tool 8 after reaching the bonding surface is finely regulated, so the melting point is relatively low. In the case where low solder bumps 4... are adopted, the bonding tool 8 may descend excessively as the solder bumps 4... melt, and the solder bumps 4...
... can be prevented from being too crushed. and,
It is possible to prevent the occurrence of defects in the semiconductor chip 3, and it is possible to prevent a decrease in reliability.

Here, as is clear from the explanation in this embodiment, the speed profiles of the high-speed descending region A1, the low-speed descending region B1, and the high-speed ascending region E of the bonding tool 8, from the high-speed descending region A to the low-speed descending region B of the bonding tool 8. The transition sliding position m, the profile of the pressing force when applying pressure to the inner leads 6 and bumps 4, the predetermined descending distance Ω of the bonding tool 8 from the bonding surface, the bonding time t, etc. are controlled. The unit 40 can be easily programmed.

In addition, in this embodiment, a bonding tool that is heated continuously is explained, but the present invention is not limited to this. For example, the bonding tool that is heated continuously is used. 19. A bonding tool that can be heated may be used, and heating of the bonding tool may be started after the bonding tool reaches the bonding surface.

Then, after the bonding tool descends by a predetermined distance ρ as the solder bumps 4... melt, the heating is stopped,
Rapidly cool the bonding tool by blowing compressed air, etc.
By raising the bonding tool after solidifying the solder bumps 4, more stable inner lead bonding can be performed.

Further, in this embodiment, the strain gauge 38 is employed as the bonding tool state detection means, but in addition to this, for example, a load cell or the like may be employed as the bonding tool state detection means. Furthermore, the attachment position of the bonding tool state detection means may be any part where stress changes when the bonding tool 8 reaches the bonding surface. Conceivable.

20 In addition, in this embodiment, the driving force of the rotary servo motor 31 is transmitted from the ball screw 35 and the nut 34 to the bonding member 7 to move the bonding tool 8 up and down. Although the detector 37 is directly connected, the present invention can displace the bonding tool 8 in proportion to the amount of drive of the servo motor 31, and detect the amount of drive of the servo motor 31 to determine the position of the bonding tool 8. It is only necessary to provide a position detecting means that can detect the position, and various other modifications are possible.

For example, as shown in FIG. 4, a linear motor 51 is employed as the driving means, and the linear motor 51 directly drives the press rod 21 (and bonding crane 8) to move it up and down, and also adjusts the position of the press rod 20. The detection may be performed using the linear position detector 52.

Furthermore, in this embodiment, after the bonding tool 8 is bent by a certain amount as the solder bumps 4 melt, the lowering of the multiple bonding tool 8 and the application of pressure by the bonding tool 8 are stopped. However, the present invention is not limited to this. For example, as in the conventional case, after the bonding tool 8 reaches the bonding surface, the bonding tool 8 may be pressurized for a predetermined period of time, and then the bonding tool 8 may be raised. good.

[Effects of the Invention] As explained above, the present invention provides an inner lead bonding apparatus that press-bonds a semiconductor chip and an inner lead of a wiring pattern, which includes a bonding tool that presses the semiconductor chip and the inner lead, and is integrated with the bonding tool. a bonding member that is movable up and down; a drive means for directly driving and displacing the bonding member; a bonding tool position detecting means based on the amount of drive of the drive means; A bonding tool state detection means for detecting that the semiconductor chip and the inner lead are in contact with each other is provided.

Further, based on the outputs of the bonding tool position detecting means and the bonding tool state detecting means 22, an electric signal is output to the driving means, and the magnitude of the electric signal output to the driving means is changed to increase the pressing force of the bonding tool. A control unit is provided to adjust the

The present invention also includes a bonding member that has a bonding tool that presses the semiconductor chip and the inner lead and is movable up and down integrally with the bonding crane, a drive means that directly drives the bonding member to displace it, and a drive amount based on the drive amount of the drive means. bonding vine position detection means for detecting the position of the bonding tool; bonding tine state detection means for detecting that the bonding tool has reached the bonding position and brought the semiconductor chip and the inner lid into contact; and a control section for controlling the amount of displacement of the bonding tool based on the output of the bonding tool state detection means.

Furthermore, in the 23-in-2 lead bonding method in which inner leads of a wiring pattern are thermocompression bonded to electrode bumps protruding from a semiconductor chip, a bonding tool provided on a bonding member that can be raised and lowered is allowed to reach the bonding surface. The first step is to press the inner lead to the electrode bump, and a certain pressure is applied to the bonding tool, and when the bonding tool is displaced as the electrode bump melts and reaches a predetermined position, the bonding tool is pressed into contact with the electrode bump. and a second step of stopping the gul.

Therefore, the present invention has the effect of being able to control the position and pressing force of the bonding tool with a simple configuration, and further improving reliability by preventing the occurrence of defects in semiconductor chips.

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment of the present invention.
The figure is a schematic configuration diagram, and Figure 2 is a block diagram showing the control circuit.
Fig. 3 is a diagram showing the raising and lowering movement of the bonding tool together with the output signal of the strain gauge and the input current of the servo motor, Fig. 4 is a schematic configuration diagram showing a modified example, and Figs. 5 to 7 are conventional examples. Fig. 5 is a schematic configuration diagram, Fig. 6 is an enlarged side view of the main part 2 4 , and Fig. 7 (a) shows the state when the bonding tool reaches the bonding surface. FIG. 7(b) is an enlarged side view showing the state when the solder bumps are melted. DESCRIPTION OF SYMBOLS 1... Inner lead bonding device, 3... Semiconductor chip, 4... Electrode bump, 6... Inner lead, 7... Bonding member, 8... Bonding tool, 31... Servo Motor (drive means) 37.
・・Position detector (bonding tool position detection means),
38... Strain gauge (bonding tool state detection means), 40... Control unit.

Claims (4)

[Claims] (1) In an inner lead bonding device that presses a semiconductor chip and an inner lead of a wiring pattern, a bonding member that has a bonding tool that presses the semiconductor chip and the inner lead and is movable up and down together with the bonding tool; A drive means for directly driving and displacing the bonding member; a bonding tool position detection means for detecting the position of the bonding tool based on the amount of drive of the drive means; and bonding tool state detection means for detecting that the inner lead and the inner lead are brought into contact with each other. (2) An electric signal is output to the driving means based on the outputs of the bonding tool position detecting means and the bonding tool state detecting means, and the magnitude of the electric signal output to the driving means is changed to increase the pressing force of the bonding tool. A claim characterized in that a control section for adjusting is provided (
1) The inner lead bonding device described above. (3) In an inner lead bonding device for press-bonding a semiconductor chip and an inner lead of a wiring pattern, a bonding member that has a bonding tool for press-bonding the semiconductor chip and the inner lead and is movable up and down integrally with the bonding tool; A drive means for directly driving and displacing the bonding member; a bonding tool position detection means for detecting the position of the bonding tool based on the amount of drive of the drive means; a bonding tool state detection means for detecting that the inner lead is in contact with the inner lead; and a control section for controlling the displacement amount of the bonding tool based on the outputs of the bonding tool position detection means and the bonding tool state detection means. An inner lead bonding device characterized by comprising: (4) In an inner lead bonding method in which inner leads of a wiring pattern are thermocompression bonded to electrode bumps protruding from a semiconductor chip, a bonding tool provided on a bonding member that can be raised and lowered is brought to the bonding surface and the inner leads are bonded. a first step of press-contacting the electrode bump to the electrode bump, and applying a constant pressure to the bonding tool, and when the bonding tool is displaced as the electrode bump melts and reaches a predetermined position, the bonding tool and a second step of stopping the inner lead bonding method.