JPH0528905B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a substrate transport method for accurately positioning and placing a substrate such as a lead frame or a printed circuit board at a bonding position in order to perform die bonding or wire bonding. It is something.

[Prior art]

Conventionally, as a transport method for accurately positioning and placing a substrate from a standby position to a bonding position, the substrate at the standby position is sandwiched between a pair of upper and lower rollers, and the rollers are rotated a predetermined number of rotations before being placed at the bonding position. There is.

[Problem that the invention seeks to solve]

However, with this method, it is difficult to accurately position the lead frame at the standby position, the rollers tend to slip, and it is difficult to obtain accurate roller diameters, so highly accurate positioning cannot be performed. This had become a problem.

The present invention is intended to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a method that allows easy and accurate positioning to a bonding position.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention provides a substrate transport method for transporting a board to be bonded along a guide rail to a bonding position, in which a gripping mechanism for gripping and releasing the board is provided. attaching a nut to a screw rod and reciprocating the gripping mechanism by rotating the screw rod in forward and reverse directions;
Detecting the front edge of the substrate, stopping the screw rod when the screw rod has rotated a predetermined number of rotations from the detected position, and releasing the gripping mechanism to place the substrate at a predetermined bonding position. The present invention is intended to provide a characteristic substrate transport method.

[Effect]

By having the above-described configuration, the present invention has the following features:
detecting the front edge of the board carried by the gripping mechanism;
The gripping mechanism is moved from the detection position while counting the number of rotations of the screw rod, and when the screw rod is stopped when the predetermined number of rotations required for transportation from the detection position to the bonding position is reached, the substrate is bonded. accurately transported to the location. Therefore, accurate positioning can be performed without requiring positioning at a standby position.

In addition, the board is securely gripped by the gripping mechanism,
Accurate travel distance corresponding to the number of rotations of the screw rod can be obtained.

〔Example〕

An embodiment in which the present invention is applied to a transportation method for placing a lead frame at a die bonding position will be described with reference to the drawings.

In FIG. 1, a reciprocating gripping mechanism 2 grips a lead frame 1, runs on a pair of guide rails 3, 3, and feeds the lead frame 1 to a bonding position where its tip reaches position A. This is a lead frame conveying device which holds a lead frame 1 which has been die bonded by a die bonder (not shown) again with a gripping mechanism 2 and sends it out from a bonding position where the tail end of the lead frame 1 reaches position B. Lead frame 1 in bonding position
Pitch feeding from the front end edge of position A to the rear end edge of position B is also carried out by gripping mechanism 2.

The gripping mechanism 2 includes a feeding claw 4 and a feeding claw 5,
Its base is connected to a nut 7 attached to a threaded rod 6. Usually, ball screws are used for the screw rod 6 and the nut 7.

The threaded rod 6 is supported by a bearing member 8 and is provided with a motor 9 capable of forward and reverse rotation as a driving source.

The feed-in claw 4 and the feed-out claw 5 are arranged to hold the lead frame 1 where the feed claw 4 is waiting when the gripping mechanism 2 is retracted the most towards the standby position of the lead frame 1.
so that the feed-out claw 5 can grasp the lead frame 1 whose rear edge is at position B, that is, so that conveyance of the lead frame 1 from the feed-in claw 4 to the feed-out claw 5 can be relayed. The interval and movement stroke are set.

The lead frame 1 is gripped by the feeding claw 4 and facing any part of the running path, that is, the lead frame 1 is fed to the standby position with the front edge having an error of range C. A detection unit 10 is provided which sometimes faces any part of the running path within the range D and detects the front edge of the lead frame 1. After detecting the front edge, the detection unit 10 controls the motor control unit 11 to stop the rotation of the motor 9 after a predetermined number of rotations.
has been contacted. The predetermined number of rotations is determined by the detection unit 10.
It can be found by dividing the distance between the detected position E and the position A by the lead of the threaded rod 6.

A detection unit 12 that detects that the lead frame 1 is in a standby position where it can be gripped by the feeding claw 4 that is retracted the most is connected to a supply mechanism (not shown) that supplies the lead frame 1 to the standby position in range C. ) is provided facing the lead frame 1 running path.
The detection section 12 is connected to the opening/closing drive section of the feeding claw 4 via an opening/closing control section (not shown) which constitutes a control mechanism together with the motor control section 11 . The opening/closing drive section of the delivery claw 5 is also controlled by the opening/closing control section.

The feeding claw 4 and the feeding claw 5 will be explained using FIG. 2. Each claw consists of an upper claw 13 fixed to the arm of the gripping mechanism 2 and a lower claw 14 swingably provided on the arm. It is equipped.

The opening/closing drive unit 15 includes a solenoid 16 fixed to the arm of the gripping mechanism 2, and a pin 17 slidably provided in a vertical through hole provided in the solenoid 16. The pin 17 has an end protruding from the upper end of the solenoid 16. The lower claw 14 is in contact with the lower claw 14 and is provided with a head 18 that is a detachment prevention part, and the end that projects from the lower end of the solenoid 16 is provided with a disc 19 that comes into contact with and separates from the solenoid 16 when the solenoid 16 is turned on and off. .

The gripping mechanism 2 formed as described above is provided facing only one side of the guide rails 3, 3, and is configured to grip one side edge of the lead frame 1 parallel to the transport method and transport the lead frame 1. and the guide rail 3 on which the gripping mechanism 2 is provided
are provided so as not to obstruct the movement of the feeding claw 4 and the feeding claw 5.

Note that this lead frame conveying device is of a type in which the stroke is divided into two stages due to space limitations.

Next, the operations will be explained using FIGS. 3a and 3b.

In this example, a pusher 2 that pushes out frames one by one from a magazine 20 serves as a mechanism for feeding lead frames (hereinafter referred to as frames) 1 to a standby position.
1 is used. The pusher 21 and the drive section (not shown) of the magazine lifting/lowering mechanism are also connected to the control mechanism.

...In the starting state, the gripping mechanism 2 is in the most retracted position.
Both the feed claw (hereinafter abbreviated as claw) 4 and the feed claw (hereinafter abbreviated as claw) 5 are opened.

...The frame 1 is pushed out by the pusher 21.

...The detection unit 12 detects the supply of frame 1,
The frame 1 is gripped with the claws 4 closed. At this time, the claw 4 grips the tip of the frame 1.

...The gripping mechanism 2 is advanced at low speed, and the frame 1 is
The detection unit 10 detects the front edge of the image. Start counting the number of rotations of the threaded rod 6 in the transport direction (positive) from the detection position.

...The gripping mechanism 2 is advanced at high speed. screw rod 6
When the number of rotations reaches approximately half of the predetermined number of rotations or reaches the number of rotations, the forward rotation of the screw rod 6 is stopped and the gripping mechanism 2 is stopped. Therefore, counting of the number of rotations is also stopped. Lead frame 1 is in a fixed position in the middle.

...Open claw 4 and release frame 1 once.

...The screw rod 6 is rotated in the opposite direction to return the gripping mechanism 2 by an appropriate distance.

...Claw 4 is closed. The claw 4 grips the middle part of the frame 1.

...The screw rod 6 is rotated in the forward direction to move the gripping mechanism 2 forward at high speed. Restart counting the number of rotations of screw rod 6. When the total of the count from and the current count reaches a predetermined number of rotations, the forward rotation of the screw rod 6 is stopped, and the gripping mechanism 2
to stop. At this time, the leading end of the frame 1 is at position A, and the leading end bonding part 22-1 of the plurality of bonding parts 22-1, . . . 22-n of the frame 1 is determined to be the bonding position. The detection unit 12 is turned off, and the magazine 20 is lowered by one stage to set the next frame 1 at the ejection position.

...Open claw 4. The pusher 21 pushes the next frame to the standby position.

...Bonding starts, and the gripping mechanism 2 retreats by one pitch of the bonding site. Part 22-
1 bonding completed.

...Close claw 4.

...The gripping mechanism 2 is advanced by one pitch, that is, until the next bonding part 22-2 is at the bonding position.

...The bonding is completed by feeding the claw 4 to the bonding part 22-(n-1).

...Close claw 5.

...The frame 1 is advanced by one pitch using the claw 5. The bonding part 22-n is the bonding position.

...Open the claw 5 and bond the part 22-n.
Bonding to. This completes bonding to frame 1.

~...Keep the claws 5 open and do ~. (
The next frame is carried by the claw 4 to an intermediate fixed position.

…With claws 4 and 5 closed, perform 〓〓…. The next frame 1 is carried by the pawl 4 from an intermediate fixed position to a fixed position. The frame 1 with completed bonding is carried by the claws 5 from the position where the bonding part 22-n is at the bonding position to the delivery position. After that, the claw 5 is opened and the frame 1 is sent out by the claw 5.
is transported to the next process by a transport mechanism as appropriate.

Repeating the following operations: In the above embodiment, the detection unit 10 is installed in a state where the first bonding part of the board is positioned at the bonding position, and is away from the final end of the board toward the supply side of the board. However, in order to shorten the transportation time and prevent deterioration of positioning accuracy due to cumulative errors of the feed screw, etc., it is better to place the detection position of the substrate close to the bonding position. That is, it is possible to shorten the transport time by shortening the transport distance of the feed screw.

In addition, although the explanation has been made using a type in which the stroke is divided into two stages, the length of the screw rod 6 may be increased to increase the length of the holding mechanism 2.
In FIG. 3A, the stroke can be such that the lead frame 1 can be moved from the position to the position at one time, or the pusher 21 can be configured to push the lead frame 1 from the position to the position. If you do this, it can be supplied in one stroke.

[Effects of the Invention] Since the present invention detects the front edge of the substrate and counts the conveyance distance from the detected position, it is possible to accurately and easily position the substrate at the bonding position. A remarkable effect can be achieved in practical use.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view, FIG. 2 is a partial perspective view, and FIGS. 3a and 3b are operation explanatory views. DESCRIPTION OF SYMBOLS 1... Lead frame, 2... Gripping mechanism, 3... Guide rail, 4... Feeding claw, 5... Feeding claw, 6... Screw rod, 7... Nut, 8... Bearing member, 9... Motor,
DESCRIPTION OF SYMBOLS 10... Detection part, 11... Motor control part, 12... Detection part, 13... Upper claw, 14... Lower claw, 15... Opening/closing drive part, 16... Solenoid, 17... Pin, 18... Head, 19... Disc, 20...Magazine, 21...Putsia.

Claims (1)

[Scope of Claims] 1. A substrate conveyance method in which a substrate to be bonded is conveyed along a guide rail to a bonding position, the nut having a gripping mechanism for gripping and releasing the substrate being attached to a threaded rod. The gripping mechanism is reciprocated by forward and reverse rotation of the screw rod, the front edge of the substrate is detected, and when the screw rod has rotated a predetermined number of rotations from the detection position, the screw rod is stopped and the gripping mechanism is activated. A method for transporting a substrate, comprising opening the substrate and placing the substrate at a predetermined bonding position.