JPH01243443A - Tape bonder - Google Patents

Abstract

PURPOSE:To prevent defective bonding such as cracks of a pellet, damage to lends, peeling of leads, etc., by detecting and controlling applied pressure between a tool and the pellet during bonding. CONSTITUTION:Means (strain gages) 2 detecting pressure loading working between a tool 1 and a pellet 12, a means (encoder) 7 detecting the movement of the tool, and a means controlling the driving force of the tool on the basis of the result of the detection of these two detecting means 2, 7 are provided. The driving force of the tool is kept at a specified value when there is the movement of the tool without depending upon the presence of pressure loading, the driving force of the tool is increased gradually by stages when pressure loading is not brought to zero and there is no movement of the tool, and the driving force of the tool is further augmented when it reaches fixed pressure loading and bonding is conducted. Accordingly, the application of impulsive pressure loading and excess pressure loading is prevented even to the pellet, the accuracy of bump height of which is insufficient, thus allowing excellent bonding.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a tape bonding device that aligns and press-bonds leads on a tape and bumps formed on a semiconductor pellet, and particularly relates to a tape bonding device that aligns and press-bonds leads on a tape with bumps formed on a semiconductor pellet. The present invention relates to a tape bonding device suitable for preventing bonding defects caused by.

[Conventional technology]

In conventional tape bonding equipment, JP-A-53-10
As described in No. 5972, by lowering the crimping tool while applying low air pressure and switching the air pressure to high pressure at the start of bonding, the impact load on the pellet during bonding is suppressed. was. At that time, the air pressure is switched in synchronization with the bonding start position using a timing cam installed in the tool drive mechanism.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the fact that the height of the bump, which is the pressure point, varies between individual pellets. Therefore, for pellets with a low bump height,
There is a problem in that high air pressure is applied to the tool before the tool and the bump reach sufficient contact, and the tool applies an impact pressure to the pellet, causing pellet cracking.

However, the above-mentioned conventional technology does not take into account the fact that only a small number of bumps bear the pressure force at the initial stage of bonding due to uneven heights of the bumps on the pellet.
Excessive pressure concentrates on a small number of bumps, easily causing breakage of the lead.An object of the present invention is to reduce the impact force even for pellets with insufficient accuracy in bump height as described above. To realize a tape bonding device capable of performing excellent bonding without applying pressure or excessive pressure.

[Means for Solving the Problem] The above object is to provide a means for detecting the pressing force acting between the tool and the pellet, a means for detecting the amount of tool movement, and the above-mentioned 2.
A means for controlling the tool driving force based on the detection results of the two detected handles is provided, and if there is a tool movement amount regardless of the presence or absence of pressing force, the tool driving force is held at a predetermined value, and the pressing force is not zero. If there is no tool movement wJ violet, this is achieved by increasing the tool driving force little by little step by step, and when a predetermined pressing force is reached, further increasing the tool driving force to perform bonding.

[Effect]

The pressurizing force t-force detection means detects and outputs the sum of cutting pressures acting on each part where the tool and the pellet are in contact via the lead on the tape to the cavity. At the start of bonding, there is no contact between the tool and the pellet, and the number of contact points mentioned above is zero, so the pressure detection box also takes a value that can be considered zero except for a slight error. There is.

The means for detecting tool movement ′j# is whether the tool is moving regardless of whether it is in contact with the pellet, or whether the tool is in contact with a bump on the pellet and is stationary in a balanced state. Determine.

Based on the combination K of the detection results of the two detection means, the control means determines the current operating state of the device as follows (1) e (21
.

(3) can be determined.

(1) When the pressurizing force is zero; the tool is not in contact with the pellet.

(2) When the pressing force is not zero and there is a tool movement amount: the tool is crushing the bump with the detected pressing force.

(3) When the pressurizing force is not zero and there is no tool movement; the tool is in contact with the bump and is stationary, balanced against each other, and the detected pressurizing force is applied to the bump.

However, the control means cannot determine how many bumps are in contact with the tool and are receiving pressing force.

Depending on the above determination result, the control means sends a drive command to the tool drive source.

The tool drive source operates so that the tool drive force can be changed at any time based on the given drive command.
This makes it possible to move the tool and apply pressure at any time.

The device first receives a bonding command in state (1). Here, while detecting the pressurizing force, feedback control is applied so that the pressurizing force takes a predetermined low value, and a drive command is given to the tool drive source, and the tool starts moving, causing one or more bumps on the pellet to (2) Matasha (
3) is reached.

In the case of (2), the set value that the pressurizing force should take is kept at the predetermined low value. Therefore, the increase in pressing force x caused by the start of contact is suppressed to a low level and does not become an impactful pressing force.

Moreover, even if only one bump is in contact, the pressing force applied to the bump is the predetermined low value, so that no excessive pressing force is applied.

If the condition at the start of contact is (3), the pressing force is not sufficient to crush the bump pan in contact, so the set value that the pressing force should take is increased by a predetermined increment. In this case, the reason why no impulsive force is applied is (2
).

Thereafter, if the condition is (2), the drive command is obtained by the feedback control described above without changing the set value of the pressurizing force, and if the condition is (3), the set value of the pressurizing force is increased by a small amount and the drive command is obtained by the feedback control described above. By obeying orders, a state is maintained in which excessive pressure is not placed on wealth.

Furthermore, the set value of the pressurizing force increases, and the pressurizing force F allows it to be determined that a sufficient number of bumps are in contact with the tool. Since regular bonding is started at the time when , excessive pressure on a small number of bumps is also avoided when performing regular bonding.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the appearance of the tool drive section of the tape bonding apparatus according to the present invention, (eL) is a front view, (b)
is a side view. A motor 8, which is a tool drive source, is fixed to the base 6. The motor 8 is a torque-controlled servo motor, and is connected to the tool stage 4 via a ball screw 5t.
t-drive, thereby moving the tool 1 up and down IC. The rising movement is detected by the encoder 7, which is a moving amount.

In addition, if the tool 1 comes into contact with the pellet 12 via a lead on a tape (not shown) (7'), the pressing force deforms the elastic member 5 installed between the tool 1 and the tool stage 4, causing the deformation. t'fr is detected by strain gauges 2 attached to the elastic members 3 on the front, rear, left, and right sides.Since the deformation capacity of the elastic member 3 is proportional to the applied force, in this embodiment, this strain gauge 2 is used as the applied force detection means. ing.

Control block at second in the tool drive section configured as above
As shown in the figure. Pressure force 11 exerted by tool 1 on pellet 12
is detected by the strain gauge 2 and input to the control device 13, which is means for controlling the tool driving force.

On the other hand, since the movement t10 of the tool 1 is determined by the amount of rotation of the motor 8, it can be detected by the encoder 7, and the pressing force 1
1 is input to the control device 13. Inside the control device 13, a drive command 9 to be sent to the motor 8 is determined from time to time by an algorithm to be described later.

The operation of the "self*sho example" will be explained below based on the algorithm shown in FIG.

In the initial state, the tool 1 is separated from the pellet 12 and the lead on the tape. Upon receiving the bonding start command 14, the control device 16 causes the tool 1 to move 1i10'i.
It is input from the encoder 7 and is stored in the memory as the current tool position [-1] (step 31). Then, substitute the initial pressing force fot into the pressing force set value fr (step 62)
After this, the process moves to repeated execution of the tool drive control loop shown in steps 65-38.

First, the pressing force 11 detected by the strain gauge 2 is input as the current pressing force value f (step 33), a servo calculation is performed between this and the pressing force set value fr, and the result is the tool drive source. It is output to the motor 8 as a drive command 9.

(Step 34). Subsequently, the tool movement amount 10 detected by the encoder 7 is input as the tool current position (step 35), and the previously detected value 2. compared to (
Step 36).

If X6 and 21.1 are not equal, that is, if the tool 1 is moving, the process returns to the previous application of the repeat loop while keeping the pressurizing force set value hk unchanged. This may be because the tool 1 has not yet contacted the pellet 12, or because the initial pressure applied to the bump is not correct. Either of the following conditions (1):

Corresponds to (2).

If zo and - are equal, that is, if there is no movement of the tool, compare the pressurizing force setting value fr with a predetermined bonding startable pressurizing force Fa (step 57), and if it is not greater than Fa, then Increase by a predetermined increment j and return to the beginning of the repeat loop (step 68
). This corresponds to the state (3) K in which the tool 1 is balanced and stationary while pressing the bump.

After repeating the loop of steps 55 to 38 until the pressure setting value becomes larger than the bonding start force Fa of the folding index, the pre-added bonding load Fb is set as the pressure force setting value. (step 39), and then the tool 1t
- Retract (step 40) and end the bonding operation. At this time, the value of Pa is experimentally determined on the condition that a sufficiently large number of bumps are in good condition with the tool 1.

Figure 4 shows tool 1 corresponding to the progression of the above algorithm.
This diagram illustrates the change in the contact state between the bump 15,1<S and the bump 15,1<S. Here, for ease of understanding, the bumps shown in the figure are the bumps 15 that come into contact with the tool 1 at the earliest stage, and the bumps whose pressing force setting value f1- is F. It is limited to two bumps, 9 bumps 16, which come into contact with the tool 1 at the latest before becoming larger.

In the same figure (α), the tool 1 is in a state where it is descending to the contact edge 1 with any bump as the initial pressing force foe is set as the pressing force setting value. Φ) is the pressing force f when the tool 1 contacts the bump 15
, shows a balanced state. ←) Gradually increases the pressure and crushes the bump 15 while pressing the tool 1.
is in a downward state, and at this time, the pressing force is rounded to the minimum value necessary to continue crushing the bump 15, and an impulsive pressing force or an excessive pressing force is not applied to the bump 15. do not have.

(d) shows a state immediately before the tool 1 comes into contact with the bump 16 as the tool continues to descend further. At this time, an unspecified number of bumps including bump 15t are crushed by the pressing force Pa-f. In (e), when the bank 16 is in contact with the tool 1 and the pressure setting value is larger than Fc, regular bonding is performed from this state with the predetermined bonding load F'bk pressure force setting value. .

As can be seen from the above description, according to this example, even if the height of the bumps varies like pellets, the impactful load change when the tool and the bumps come into contact can be suppressed within a predetermined initial pressing force. It has the effect of Further, there is an effect that application of excessive pressure to a small number of bumps at the initial stage of bonding can be avoided.

〔Effect of the invention〕

According to the present invention, the pressing force between the tool and the pellet during bonding can be constantly detected and controlled, and the pressing force can be set according to the contact state between the tool and the bump and the crushing state of the bank during bonding. Even if there are variations in the height of the bumps, excessive pressure or impact pressure is not applied to the leads and bumps, and bonding defects such as pellet cracking, lead breakage, and lead peeling can be prevented.

[Brief explanation of the drawing]

Fig. 1 (α) is a front view of an embodiment of the present invention, (in the figure) is a side view thereof, Fig. 2 is a control block diagram of tool drive in this embodiment, and Fig. 3 is a bonding diagram in this embodiment. FIG. 4 is an explanatory diagram showing each state during bonding corresponding to the progress of the algorithm in FIG. 3. DESCRIPTION OF SYMBOLS 1... Tool, 2... Strain gauge which is pressurizing force detection means, 3... Elastic S material, 4... Tool stage, 5...
...Ball screw, 6...Base, 7...Encoder that is tool movement amount detection means, 8...Motor that is tool drive source, 9...Drive command signal, 10...Tool movement amount , 11...7JO8E force, 12...pellet, 13...control device which is tool drive control means, 14
. . . Bonding start command signal, 15. i6... bump, z! l...Tool current position signal, fo...Initial force, f,...Preset force value, Fa...Pressure force that allows bonding to start, F,...Regular bonding load, f...Pressure pressure increment. 3rd concave 4th mouth

Claims (1)

[Scope of Claims] 1. In a tape bonding device that uses a tool that is a crimping tool to crimp and bond a lead on a tape to a pellet, there is provided a means for detecting a pressing force acting between the tool and the pellet, and a tool. A means for detecting the amount of movement and a means for controlling the tool driving force based on the detection results of the two detection means are provided, and when there is a tool movement amount regardless of the presence or absence of pressurizing force, the tool driving force is set to a predetermined value. If the pressing force is not zero and there is no tool movement, increase the tool driving force little by little step by step, and when the specified pressing force is reached, increase the tool driving force further and perform bonding. A tape bonding device characterized by performing the following steps. 2. The tape bonding apparatus according to claim 1, wherein the means for detecting the pressing force is a strain gauge attached to an elastic member installed between the tool and the tool stage.