JPH03245539A - Lead frame transfer device - Google Patents

Abstract

PURPOSE:To set the gap between a lead frame and guide rails at the minimum of a need by a method wherein it is detected that a second guide rail for guiding the end surface of the lead frame is separated from the first guide rails for supporting the lead frame and the gap between the lead frame and the guide rails is controlled. CONSTITUTION:At the time of transfer of a lead frame 1, the positions of guide rails 6, 4a and 5 are set in such a way that the width (l) of the frame 1 becomes a width of a prescribed amount L to correspond to the width (l) and a gap St1 between the rails 6 and 5 and the frame 1 is provided. At this time a conductive stopper 8a is pressed to the rail 4a and an applying voltage is applied. At the time of positioning for fixing the lead frame, the rail 4a is moved to the inner side by a pulse motor 12, the gap St1 dwindles into nothing, a gap St2 between the stopper 8a and the rail 4a is generated, a circuit is shut down and the motor 12 is stopped. Then, at the time of transfer of the frame 1, the rail 4a is moved to the outside by the motor 12, the gap St2 dwindles into notching, it is detected that a current begins to flow, the motor 12 is stopped and the transfer of the lead frame is executed in the smallest gap St1.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to a lead frame conveying device used in the manufacture of semiconductor devices, and in particular, to a lead frame conveying device used in the manufacture of semiconductor devices. It is used for transportation.

(Prior art) In the manufacture of semiconductor devices, die bonding involves fixing the semiconductor chip to a lead frame in order to attach lead leads to the electrodes on the semiconductor chip after the wafer process, and the bonding between the electrodes on the chip and the leads on the lead frame. Processes such as wire bonding for wiring between the chips and resin sealing for covering the chips and leads are then performed. In these steps and between steps, since the steps are performed in units of lead frames, it is an important element to transport the lead frames quickly and accurately.

Various types of lead frames are used depending on the shape of the semiconductor device, the number of bins, etc. Since lead frames are transported with multiple chips mounted on a single board, the width of the 5-lead frame has been standardized to facilitate storage and transport, but it is still important to avoid having several widths. The current situation is that it cannot be done. Similarly, there are several types of lead frame magazines that accommodate lead frames, depending on the width of the lead frame. Therefore, the width of the guide rail can be varied in lead frame transport equipment that transports between processes. It is now possible to do so. Also,
By adjusting the width of the guide rail based on the width information read out according to the type of lead frame from the storage section in the control device that stores width information for each type of lead frame, manual adjustment can be made unnecessary. It is publicly known (Japanese Unexamined Patent Publication No. 172731/1983).

FIG. 4 is a sectional view in the lead frame width direction of a lead frame conveying device of the prior art, FIG. 5 is a block diagram showing the relationship between the control device and the drive section of this technology, and FIG.
A flowchart showing the guide rail changing operation in the control device shown in the figure, and FIG. 7 is a schematic plan view of the device shown in FIG. 4.

When the lead screw 11 is rotated by the pulse motor 12, the nut 9 and the first guide rail 4a engaged with the lead screw 11 move in the width direction of the lead frame 1. The pair of guide means includes a first guide rail 4a that supports the lead frame 1 and a second guide rail 6 that is slidable in the width direction of the lead frame and is urged inward by a tension spring 7. It is composed of one guide means and a guide rail 5 which is the other guide means. The stopper 8 in the sliding direction provided on the second guide rail 6 is
By hitting the end face of the guide rail 4a, the second
The limit of the closing movement of the guide rail 6 is determined.

The lead frame 1 is transported by a driving device 51 that moves the first guide rail 4a and the second guide rail 6 by a predetermined amount between the guide rail 5 and the second guide rail 6 and the lead frame 1. This is done after providing a gap St' in the . When fixing the lead frame 1 for wire bonding or the like, the drive device 51 closes it by a predetermined amount B, and the tension spring 7 closes as the first guide rail 4a moves.
The second guide rail 6 biased by the groove 4b also moves inward.

5b holds down the lead frame 1 by the pressure of the spring 5. Here, the opening/closing amount A by the drive device 51.

B is performed by the amount set in advance by the input unit 50, and operates at a constant amount except when setting up to change the type of lead frame.

At the time of setup, as shown in Figure 6, input the width information of the lead frame in advance, and then input the information of the type of lead frame you want to produce.
2 to drive pulse output 104 are automatically performed by the drive device 51.

In the conventional example, variations in the width dimensions of the lead frame, differences in thermal expansion, etc. were absorbed by differences in the amount of deflection of the springs. Therefore, the opening/closing amounts A and B of the guide rails during transportation and fixation (that is, positioning) need to be greater than including the entire range of dimensional variation and thermal expansion range.

When transporting the lead frame, a state in which the guide rail opening/closing amount A is large and the gaps S and I are large is not preferable, as the lead frame 1 will have room to rotate as shown in FIG. 7, resulting in an error in positioning. Furthermore, the guide rail 4a,
6 and the lead frame 1, the risk of getting caught by the edge portion of the lead frame 1 increases. Therefore, in the conventional example, the guide rail opening/closing Ji
A, B.

It was necessary to make appropriate modifications for each production lot of lead frames.

The amount of opening/closing of the guide rail is also related to the increase/decrease in the time required for transport positioning, and it is also necessary to achieve a short amount of time with the minimum necessary amount of opening/closing.

(The illumination that the invention seeks to solve) As mentioned above, the guide rail needs to be modified appropriately for each production lot of lead frames so that the amount of opening and closing is appropriate, and this must be done in as short a time as possible. I had to.

The present invention was made in order to realize a highly accurate lead frame conveying device that allows product types to be changed with a simple operation, shortens the time required to convey and position lead frames, etc. The gap between the rail and
The aim is to automatically control to the minimum necessary level.

[Structure of the invention]

(Means for Solving Problem No. 111) The present invention provides a lead frame transport device in which at least one of a pair of guide rails supporting and guiding both ends of the lead frame is reciprocated in the width direction of the lead frame, and the other guide rail is moved reciprocally in the width direction of the lead frame. The rail is divided into a first guide rail that supports the lead frame and a second guide rail that guides the end surface of the lead frame, and the second guide rail that guides the end surface of the lead frame is movable in the width direction. of.

The lead frame is biased inward so as to be close to the first guide rail that supports the lead frame, and the guide rail is moved in the width direction of the lead frame to narrow the guide rail so that the lead frame is sandwiched between the guide rails. After that, if the guide rail is made narrower, it is detected that the second guide rail that guides the end face separates from the first guide rail that supports the lead frame, and depending on the detection position at that time, the gap between the lead frame and the guide rail is determined. It is characterized by controlling.

(Function) By detecting that the second guide rail that guides the end surface is separated from the first guide rail that supports the lead frame, and controlling the gap between the lead frame and the guide rail based on the detected position at that time, the conveyance is performed. To minimize the gap between a lead frame and a guide rail during operation, and to enable automatic control. This means for detecting the relative position of the first guide rail and the second guide rail may be a displacement sensor that uses a change in eddy current or a displacement sensor;
There are methods such as using sensors such as contact sensors and guide rails as electrical contacts.

(Example) An example of the present invention will be described with reference to FIG. 1(a) and FIG. 1(b). Figure 1 (a) is a sectional view of the state in which the guide rail is opened and the lead frame is being transported, and Figure 1 (b)
) is a sectional view with the guide rail closed and the lead frame fixed.

The first guide rail 4a is moved in the width direction of the lead frame 1 by the pulse motor 12, and the second guide rail 6, which is slidable in the width direction of the lead frame, is biased inward by a tension spring 7. Conductive stopper 8 made of copper or the like
It is determined that the inward closing movement is restricted by a. The conductive stopper 8a is applied with +5V, and the first guide rail 4a is connected to the ground line, and electrically detects whether the +5V applied to the conductive stopper flows to the ground line or not. circuit-
It is configured to detect at h. Here, the first guide rail 4a is made of a conductive member, and the conductive stopper 8a is electrically insulated from the second guide rail 6.

When transporting the lead frame, move the guide rail 6.4a so that the lead frame has a predetermined amount (L) corresponding to the lead frame width (Q).
and 5, and set the gap S j with lead frame 1.
Provide l. At this time, the conductive stopper 8a is pressed against the 1'-th guide rail 4a by the tension spring 7, and the applied voltage is flowing.

When fixing the lead frame position, use pulse motor 1.
2, the first guide rail 4a is moved inward to form the gap S. The pulse motor 12
stop.

Next, when transporting the lead frame, the first guide rail 4a is moved outward by the pulse motor 12, and the pulse motor 12 is stopped when it is detected that the gap S, 22 has disappeared and the current has started to flow. , the smallest air gap St+ performs the conveyance.

The gap Stx between the lead frame and the guide rail is set to a size that takes into account the range of variation in the lead frame width (Q) and dimensions for the first operation such as when starting production of a new lot. From the operation, the operation is performed with the minimum gap St1.

(Embodiment 2) FIG. 6 is a sectional view showing the second embodiment.
2, it is driven to be in a symmetrical position with respect to the center line CL. Therefore, the center position of the lead frame 1 is always constant, and there is no need to adjust the relative positional relationship when performing die bonding and wire bonding.

FIG. 3 is a plan view of the second embodiment, in which the lead frame is conveyed from left to right. A linear guide 14 is provided on the base 21 in a direction perpendicular to the conveying direction, and sliders 28 and 29 having an oval-shaped cross section are slid on the linear guide 14. Nuts 9' and 10' that engage with the lead screw 11 are embedded in the vertical walls of the slider, and guide rails 4 and 5 are respectively attached to the upper ends.

A pulse motor 12 is fixed to the base 21 by a motor bracket 13, and its rotation causes the lead screw 11 to rotate and change the distance between the guide rails 4 and 5. The second guide rail 6 on the guide rail 4 side is oriented in a direction in which the lead frame width is reduced by a tension spring 7, and a conductive follow pin 27 is provided below.
a is provided through an insulating bushing 27b, and +5■ is applied for detecting the lead frame width. In addition, the slider 28 is equipped with a pulse motor for opening and closing the second guide rail.
18 is attached, and one end of a lever 25 for opening and closing the second guide rail is engaged with its eccentric shaft. This lever 25 is rotatably attached to a slider 28 at a lever fulcrum 20. The lever 25 has a bearing 2 on the other end.
6 is rotatably attached and comes into contact with the conductive follow pin 27a of the second guide rail 6 by the action of a tension spring 7. The lever 25 is connected to the ground line and has a bearing 26 and a conductive follow pin 27.
+5V for lead frame width detection is applied via a.

By rotating the pulse motor 18, the guide rail 6 can be opened and closed independently of the guide rail 4 via the eccentric shaft.

In transporting the lead frame, the guide rail 4.5 is set to a predetermined amount, the second guide rail 6 is expanded to its maximum weight, the lead frame is introduced into the guide rail, and the frame chuck is reciprocated (not shown). position). At this time, since there is a limit to the stroke of the reciprocating movement of the frame chuck, the operation of chuck → conveyance → chuck opening → return → check is repeated several times, but during the first conveyance, the second guide rail is moved to the maximum The operation of the present invention is performed from the second time onwards, and the gap between the lead frame and the guide rail is controlled to the minimum necessary.

In this embodiment, the transfer operation is performed, but by performing the same operation when calibrating the device and teaching the conditions, the work is simplified and the number of operational errors is reduced. In recent years, short tapes for tab bonding and the like have begun to be used in place of lead frames for semiconductor devices, and the present invention can also be applied to their transportation.

Furthermore, the configuration is not limited to the configuration of this embodiment. For example, although a tension spring is used as the biasing means, other materials with elastic properties or electromagnetic force (solenoid) may also be used, or a conductive stopper or bottle may be used to detect the lead frame width. Although the electric contact is formed using the sensor, as mentioned above, the same function can be achieved even if it is replaced with a displacement sensor or the like.

Furthermore, although pulse motors, lead screws, and eccentric cranks are used to drive the guide rails, linear pulse motors, voice coil motors, etc.
It is also possible to use a linkage mechanism.

Conventionally, the gap between the lead frame and the guide rail was set to 0.
3mm, the extension amount of the tension spring is 0.3mm, and the total is 0.
．． The opening/closing operation was performed with a gap of 6mo+, and the time required for it was 30 seconds with a 1000pps pulse motor with a resolution of 20μs, and 60Ll for a round trip, but the opening/closing operation was performed with a gap of 0.06mm, an extension of 0.06mm, and an opening/closing operation. 0.12m + time required for round trip can be about 12m5.

Additionally, the number of condition setting items for the device is reduced, making maintenance and management easier, and troubles such as lead frame crashes are also reduced, making it possible to provide a device with high production efficiency.

〔Effect of the invention〕

According to the present invention, it is possible to change the type of semiconductor device with a simple operation. Additionally, it has become possible to minimize the gap between the lead frame and the guide rail during transportation. Further, since automatic control can be performed in response to dimensional variations and differences in thermal expansion of the lead frame, it is possible to realize a highly accurate lead frame transport device with short transport positioning time.

[Brief explanation of drawings]

FIG. 1(a) is a sectional view of a lead frame conveying device during transportation according to the first embodiment of the present invention, and FIG. 1(b) is a sectional view of the lead frame conveying device during fixation according to the first embodiment of the present invention. 2 is a sectional view of the second embodiment, FIG. 3 is a plan view of the second embodiment, FIG. 4 is a sectional view of a conventional lead frame conveying device, and FIG. 5 is a sectional view of a conventional lead frame conveying device. FIG. 6 is a block diagram of the control device and drive unit of the technology, FIG. 6 is a flow diagram showing the guide rail changing operation of the prior art, and FIG. 7 is a plan view of the conventional conveying device. 1... Lead frame, 2... Pellet, 3...
...Heater, 4...First guide rail. 5... Guide rail, 6... Second guide rail,
7...Tension spring, 8...Stopper, 4b,
5b... Guide rail groove, 8a... Conductive stopper 9... Guide rail with nut, 9', 10'... Nut, 11... Lead screw, 12... Pulse motor 13... Motor bracket, ]4... Linear guide, 18... Pulse motor for opening/closing, 19.
...Eccentric shaft, 20...L//(-fulcrum, 21.
...Base, 25...Lever, 26...
Bearing, 27a... Conductive follower bin, 27b
...Insulating bushing. 28, 29...Slider, 30...Linear guide.

Claims (1)

[Claims] A pair of guide means for engaging and supporting the lead frame, a driving means for moving at least one of the pair of guide means in the width direction of the lead frame, and a conveying means for conveying the lead frame in the longitudinal direction thereof. and one of the pair of guide means includes a first guide rail that supports the lead frame, and a second guide rail that is movable in the width direction and is urged to approach the first guide rail. In the lead frame conveying device, when at least one direction of the pair of guide means is narrowed in the width direction of the lead frame, the lead is moved by the other guide means facing the second guide rail. A lead frame conveying device comprising means for detecting a point where a frame is sandwiched in the width direction, and controlling the width of a guide means based on the sandwiching point.