Workpiece stage device

Abstract

A workpiece stage device according to the present invention is configured such that a recess 16 is provided on a rear surface 11a of a vibration absorption sheet 11, and a projection 18 is provided on a support surface 10a of a stage body 10. In a state where the vibration absorption sheet 11 is stuck to the support surface 10a of the stage body 10, the projection 18 is fitted to the recess 16. Thus, even if a pressing force from the workpiece acts on the vibration absorption sheet 11, a resistance force against the pressing force is generated between the recess 16 and the projection 18, so that positional deviation of the vibration absorption sheet 11 is prevented.

Description

Work Stage Device

[0001] The present invention relates to a workpiece stage device that is incorporated into a wire bonding apparatus used in the semiconductor manufacturing process, and that slides a workpiece fed onto a workpiece sliding surface on its upper surface to place it in a working position.

[0002] As is well known, a wire bonding apparatus is an apparatus that connects electrodes of an integrated circuit formed on a semiconductor chip to electrodes of a lead frame with conductive wires (see, for example, Patent Document 1).

[0003] In this wire bonding machine, a workpiece, which is a metal frame called a lead frame with a semiconductor chip mounted on it in the previous process (die bonding), is transported by a belt conveyor. The transported workpiece is fed onto the upper surface of a workpiece stage device built into the machine from one edge side, and then a transfer robot pushes and slides the workpiece to place it in the working position.

[0004] In wire bonding machines, a tool called a capillary repeatedly presses a conductor wire against an electrode at high speed, and to absorb the vibrations that occur during this process, a vibration-absorbing sheet is provided on the top surface of the work stage device. Generally, this vibration-absorbing sheet is attached to the top surface of the work stage device using double-sided adhesive tape.

[0005] When a workpiece is transferred from the belt conveyor, a pressing force acts on the vibration-absorbing sheet in the direction of movement. If this pressing force is repeated, the vibration-absorbing sheet, which is attached with double-sided adhesive tape, will become misaligned. If this misalignment is left unattended, there is a risk that the workpiece will be damaged due to poor transport. Therefore, in the past, the vibration-absorbing sheet was replaced before the end of its life.

[0006] Japanese Patent Application Laid-Open No. 2006-165391

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a work stage device that can prevent the vibration absorbing sheet from shifting position and extend the interval between replacement of the vibration absorbing sheet.

[0008] In order to achieve the above-mentioned object, the present invention provides a work stage device that is incorporated into a wire bonding device and slides a work sent to the work sliding surface on its upper surface to place it in a working position, and includes a stage body whose upper surface functions as a support surface for the work, and a vibration absorbing sheet that is provided on the support surface of the stage body, has a smoothly finished surface, and functions as the work sliding surface, and is characterized in that a recess is provided on either the support surface of the stage body or the back surface of the vibration absorbing sheet, and the other is provided with a protrusion that fits into the recess.

[0009] In addition, the present invention can be configured so that the recesses are provided at multiple locations on the back surface of the vibration absorbing sheet, avoiding the work position, and the protrusions are provided at multiple locations on the support surface of the stage body that face the recesses.

[0010] Furthermore, the present invention may be configured such that the convex portion is provided to protrude from the support surface of the stage body, the thickness of the vibration absorbing sheet is formed to be thicker than the protruding length of the convex portion, and a hole is provided that penetrates from the back surface to the front surface of the vibration absorbing sheet, and the concave portion is formed by the hole.

[0011] According to the present invention, even if a pressing force acts on the vibration absorbing sheet in the direction of movement, the resistance force generated between the concave and convex portions prevents the vibration absorbing sheet from shifting position, thereby making it possible to extend the interval between replacement of the vibration absorbing sheet.

[0012] Fig. 1A is a plan view showing an overview of a work stage device according to an embodiment of the present invention. Fig. 1B is a front view of the same. Fig. 2A and Fig. 2B are front cross-sectional views showing enlarged recesses and protrusions provided between a stage body and a vibration absorbing sheet in a work stage device according to an embodiment of the present invention.

[0013] 1: Workpiece, 10: Stage body, 11: Vibration absorbing sheet, 12: Pressing claw, 13: Gap, 14: Working position, 15: Position shift prevention part, 16: Recess, 17: Pin, 18: Protrusion, 20: Upstream conveyor, 30: Downstream conveyor

[0014] An embodiment of the present invention will be described in detail below with reference to the drawings. A workpiece stage device according to this embodiment is incorporated into a wire bonding apparatus and has the function of positioning and supporting a workpiece at a work position. With a workpiece positioned at the work position, the wire bonding apparatus uses a tool called a capillary to connect electrodes formed in the workpiece with conductor wires. During this connection operation, the capillary repeatedly presses the conductor wire against the electrodes of the workpiece at high speed.

[0015] 1A and 1B, the workpiece stage device according to this embodiment includes a stage body 10 and a vibration-absorbing sheet 11. The stage body 10 is a support base whose upper surface functions as a support surface for supporting a workpiece 1. The vibration-absorbing sheet 11 is attached to the support surface (upper surface) of the stage body 10 with double-sided adhesive tape (not shown).

[0016] The means for fixing the vibration absorbing sheet 11 to the support surface of the stage body 10 is not limited to double-sided adhesive tape. However, since the workpiece 1 slides on the upper surface of the vibration absorbing sheet 11, a decrease in performance due to wear is unavoidable. Therefore, it is preferable to employ a fixing means that allows for easy replacement of the vibration absorbing sheet 11.

[0017] As described above, the wire bonding device repeatedly presses the conductor wire against the electrode of the workpiece 1 at high speed using the capillary. The pressing force from the capillary at this time is received by the stage body 10. The vibrations caused by the repeated high-speed pressing operation of the capillary are absorbed by the vibration absorbing sheet 11. This prevents the workpiece 1 from vibrating, enabling highly accurate positioning.

[0018] A belt conveyor (upstream conveyor) 20 is installed upstream of the work stage device, and the work 1 is transported from the previous process (die bonding process) by this upstream conveyor 20. The work 1 can be any of various semi-finished semiconductor products that require electrical connection using conductors, in addition to the aforementioned structure in which a semiconductor chip is mounted on a metal frame called a lead frame.

[0019] The workpiece 1 transported by the upstream conveyor 20 is fed in from one edge side onto the upper surface of the vibration-absorbing sheet 11 and transferred onto it. Here, in the configuration example shown in Fig. 1A, the stage body 10 to which the vibration-absorbing sheet 11 is attached is divided into three sections in the width direction, and gaps 13 are provided between each stage body 10 to form a path for the pressing claws 12 of the transfer robot to move. The pressing claws 12 protrude from below and move forward behind the workpiece 1 that has been transferred onto the upper surface of the vibration-absorbing sheet 11. The workpiece 1 is pushed by the pressing claws 12 and slides across the upper surface of the vibration-absorbing sheet 11, and is placed at the working position 14.

[0020] In addition, the means for sliding the workpiece 1 transferred onto the upper surface of the vibration absorbing sheet 11 and transporting it to the working position 14, including the configuration in which the stage body 10 is divided, is not limited to the configuration described above, and various transport means can be applied as needed.

[0021] The upper surface of the vibration absorbing sheet 11 is finished to be smooth, and functions as a work sliding surface for sliding and transporting the work 1.

[0022] After the wire bonding operation at the operation position 14 is completed, the workpiece 1 is transferred downstream by the pressure claws 12 and transferred from the other edge of the vibration absorbing sheet 11 onto a belt conveyor (downstream conveyor) 30 provided downstream. The downstream conveyor 30 then transports the workpiece 1 to the next process in the semiconductor manufacturing process.

[0023] As described above, when the workpiece 1 is transferred from the upstream conveyor 20 onto the vibration absorbing sheet 11, a pressing force acts from the workpiece 1 in the direction of movement. If this pressing force is applied repeatedly, the vibration absorbing sheet 11 will become misaligned. Therefore, the workpiece stage device according to this embodiment has the following configuration to prevent the vibration absorbing sheet 11 from becoming misaligned.

[0024] 1A, misalignment prevention sections 15 are provided between the stage main body 10 and the vibration absorbing sheet 11 at multiple locations avoiding the work position 14. The misalignment prevention sections 15 are configured by providing a recess 16 on either the support surface of the stage main body 10 or the back surface of the vibration absorbing sheet 11, and by providing a protrusion 18 that fits into the recess 16 on the other surface.

[0025] Specifically, as shown in Fig. 2A, holes are provided in the vibration absorbing sheet 11 that penetrate from the back surface 11a to the front surface (top surface), and these holes form recesses 16. Meanwhile, protrusions 18 are formed on the support surface (top surface) 10a of the stage main body 10 by protruding heads of cylindrical pins 17 embedded in the stage main body 10. Then, as shown in Fig. 2B, when the vibration absorbing sheet 11 is attached to the support surface of the stage main body 10, the protrusions 18 fit into the recesses 16 to form the displacement prevention section 15.

[0026] When the workpieces 1 are transferred from the upstream conveyor 20 to the vibration absorbing sheet 11, as shown by the arrows in Figure 2B, even if a pressing force acts on the vibration absorbing sheet 11, a resistance force is generated between the recessed portions 16 and the protruding portions 18, preventing the vibration absorbing sheet 11 from moving. This prevents the vibration absorbing sheet 11 from shifting out of position, making it possible to extend the interval between replacements of the vibration absorbing sheet 11.

[0027] Furthermore, since the concave portion 16 is formed in the vibration absorbing sheet 11, the displacement prevention portion 15 has a reduced vibration absorption capacity, and since the convex portion 18 is fitted in, if the displacement prevention portion 15 is provided at the work position 14, there is a risk that an excessive reaction force will be applied to the capillary from the convex portion 18. In this embodiment, as shown in Figure 1A, by providing the displacement prevention portion 15 at a location that avoids the work position 14, there is no risk that the capillary of the wire bonding device will press the displacement prevention portion 15, and the wire bonding operation can be carried out stably.

[0028] Furthermore, by providing the misalignment prevention parts 15 at multiple locations, it is possible to firmly resist the pressing force from the workpiece 1, making it possible to prevent even slight misalignment.

[0029] In this embodiment, the thickness D of the vibration absorbing sheet 11 is formed to be thicker than the length L of the protrusions 18 protruding from the support surface of the stage body 10 (see FIG. 2A). With this configuration, the protrusions 18 are contained within the vibration absorbing sheet 11, as shown in FIG. 2B. If the protrusions 18 protrude from the top surface of the vibration absorbing sheet 11, the workpiece 1 sliding on the top surface may collide with the protrusions 18, hindering its movement and potentially damaging the workpiece 1. The configuration of this embodiment makes it possible to avoid these obstacles.

[0030] According to experiments conducted by the inventors, by applying a product called ISODANP (registered trademark) to the vibration absorbing sheet 11, setting the thickness D of the vibration absorbing sheet 11 to 1.5 mm, and setting the protrusion length L of the convex portion 18 to 1.0 mm, it was possible to prevent the convex portion 18 from protruding from the top surface of the sheet while also being able to handle wire bonding work using various capillaries.

[0031] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible as needed. For example, a recessed portion that does not penetrate the front surface of the vibration-absorbing sheet may be formed on the rear surface. Also, a protrusion may be integrally formed when the stage body is manufactured. A configuration in which a recessed portion is formed on the stage body and a protrusion is formed on the vibration-absorbing sheet may also be used.

Claims

1. A work stage device that is incorporated into a wire bonding machine and slides a work sent to the work sliding surface on its upper surface to place it in a working position, comprising: a stage body whose upper surface functions as a support surface for the work; and a vibration absorbing sheet that is provided on the support surface of the stage body, has a smoothly finished surface and functions as the work sliding surface, wherein a recess is provided on either the support surface of the stage body or the back surface of the vibration absorbing sheet, and the other is provided with a protrusion that fits into the recess.

2. A work stage device as described in claim 1, characterized in that the recesses are provided at multiple locations on the back surface of the vibration absorbing sheet to avoid the work position, and the protrusions are provided at multiple locations facing the recesses on the support surface of the stage body.

3. A work stage device as described in claim 2, characterized in that the convex portion is provided protruding from the support surface of the stage body, the thickness of the vibration absorbing sheet is made thicker than the protruding length of the convex portion, and a hole is provided that penetrates the vibration absorbing sheet from its back surface to its front surface, and the concave portion is formed by the hole.

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