JP2002299418A - Apparatus and method for transferring micro work - Google Patents

Abstract

An object of the present invention is to provide a transfer apparatus and a transfer method for a small work capable of performing a stable transfer operation by accurately determining whether a suction state is good for a small work. SOLUTION: In a transfer apparatus of a minute work for picking up a minute chip 4 by vacuum suction and transferring it to a predetermined position, a suction flow rate of vacuum suction means for vacuum suction from a suction nozzle is first suction for suction holding. A flow rate switching means for switching between a flow rate and a second suction flow rate for detecting a suction state; vacuum suction in a state where the suction flow rate is switched to the second suction flow rate after the chip 4 is suction-held by the suction nozzle 8a; The suction state of the chip 4 to the suction nozzle 8a is determined based on the vacuum pressure detection result of the circuit. This makes it possible to increase the difference between the vacuum pressure detection values depending on the presence or absence of the workpiece suction, and to correctly determine the suction state based on the vacuum pressure even when using a small-diameter nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for transferring a minute work such as a minute semiconductor chip which is picked up and transferred.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, a transfer apparatus for picking up a work such as a semiconductor chip and mounting the work at a predetermined position is often used. In this transfer apparatus, a vacuum suction method is widely used as a method for sucking a work. After the work is sucked and held by the vacuum suction, the suction state is determined to confirm whether or not the work is sucked in a correct state. This suction state determination generally uses a method of detecting the presence or absence of a work at the lower end of the suction nozzle by an optical sensor, a method of detecting the vacuum pressure of a vacuum suction circuit in the suction nozzle, and the like. The method using vacuum pressure utilizes the fact that the degree of vacuum in the vacuum suction circuit increases when the work is sucked, and determines the presence or absence of the work and the quality of the sucked state by detecting the degree of vacuum. It is.

[0003]

However, with the miniaturization of the work, the following difficulties have occurred in the work detection by the above detection method. That is, in the method of detecting the work with the optical sensor, it is difficult to distinguish the suction nozzle and the work depending on the surface properties of the back surface of the work, and it is difficult to detect the work accurately. Further, in the method of detecting the degree of vacuum in the suction nozzle, it is difficult to determine a suction state when a small work is to be targeted, because a small-diameter nozzle having a small suction hole diameter is used.

That is, since the pressure loss during vacuum suction is large in a small-diameter nozzle, there is a large difference between the degree of vacuum in the suction nozzle when the chip is suctioned and the degree of vacuum when the chip is not suctioned. Does not occur. In comparison with the suction capacity of the suction means for vacuum-suctioning the suction nozzle, the amount of suction air sucked from the small-diameter suction hole in the absence of the work, and the difference between the work and the suction nozzle in the state where the work is suction-held. This is because there is no large difference between the amount of suctioned air and the amount of suction air sucked by the leak between the two.

[0005] As described above, the conventional micro-workpiece transfer apparatus has a problem that the quality of the suction state after the pickup operation cannot be accurately determined, and a stable transfer operation cannot be performed.

Accordingly, an object of the present invention is to provide an apparatus and a method for transferring a small work, which can accurately determine whether or not a suction state is good for a small work and perform a stable transfer operation. And

[0007]

According to a first aspect of the present invention, there is provided an apparatus for transferring a minute work, wherein the minute work is picked up by vacuum suction and transferred to a predetermined position. A suction nozzle for sucking and holding the minute work by contacting the suction nozzle, vacuum suction means for suctioning the vacuum from the suction nozzle, and a first suction flow rate which is set as the suction flow rate for suction holding for the vacuum suction means. Flow rate switching means for switching between a suction flow rate and a second suction flow rate set as a suction flow rate for detecting a suction state; a vacuum pressure detecting means for detecting a vacuum pressure of a vacuum suction circuit connected to a suction nozzle; Suction state determination means for determining the suction state of the minute work to the suction nozzle based on the vacuum pressure detection result by the vacuum pressure detection means when suction is performed at the suction flow rate.

According to a second aspect of the present invention, there is provided an apparatus for transferring a minute work according to the first aspect, wherein
Is smaller than the first suction flow rate.

According to a third aspect of the present invention, there is provided a method for transferring a minute workpiece.
This is a method of transferring a minute work in which a minute work is picked up by vacuum suction and transferred to a predetermined position, and is set as a suction flow rate for suction holding from the suction nozzle in a state where the suction nozzle is in contact with the minute work. Suctioning and holding the minute work by the suction nozzle by vacuum suction at a first suction flow rate, and switching the suction flow rate of the vacuum suction means to a second suction flow rate set as a suction flow rate for suction state detection. A step of detecting a vacuum pressure of a vacuum suction circuit connected to the suction nozzle when the suction is performed at the second suction flow rate, and determining a suction state of the minute work to the suction nozzle based on the vacuum pressure detection result. And a step.

According to a fourth aspect of the present invention, there is provided a method for transferring a minute workpiece.
4. The method according to claim 3, wherein the second suction flow rate is smaller than the first suction flow rate.

According to the present invention, there is provided a flow rate switching means for switching the suction flow rate of the vacuum suction means for vacuum suction from the suction nozzle from the first suction flow rate for vacuum suction to the second suction flow rate for suction state detection, By judging the suction state of the minute work to the suction nozzle based on the vacuum pressure detection result at the time of suction at the second suction flow rate, even when a small diameter nozzle is used, the suction state can be correctly determined by the vacuum pressure. Can be determined.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a semiconductor chip transfer device according to one embodiment of the present invention, and FIG. 2 is a timing chart of a semiconductor chip pickup operation by the semiconductor chip transfer device according to one embodiment of the present invention. It is.

First, with reference to FIG. 1, the configuration of a semiconductor chip transfer device as a transfer device for transferring a semiconductor chip, which is a minute work, to a substrate will be described. In FIG. 1, the chip supply unit 1 includes a wafer holding table 2 that is moved by an XY table (not shown). On the wafer holding table 2, a wafer sheet 3 on which a large number of semiconductor chips 4 (hereinafter simply referred to as "chips 4") are adhered in a predetermined pattern is mounted. An ejector unit 5 is provided below the wafer holding table 2. The pins 5a of the ejector unit 5 are aligned with the pick-up position of the chips 4 by the transfer head 8, and the pins 5a are projected upward so that the wafer sheet 3
Push up the chip 4 above.

A head moving unit 6 is provided above the chip supply unit 1, and the head moving unit 6 includes a moving table 7 on which a transfer head 8 is mounted. Transfer head 8
Is movable horizontally by the moving table 7, and the chip 4 pushed up by the pin 5a is moved by the transfer head 8
Is picked up by vacuum suction by the suction nozzle 8a. The picked up chip 4 is the moving table 7
And the substrate 10 placed on the holding table 9
Implemented above.

Next, a control system of the chip 4 transfer device and a vacuum suction system for vacuum suction of the suction nozzle 8a will be described. The suction nozzle 8a is provided with a suction / blow switching valve 12
Are connected to a valve 13 for turning on and off the air blow and a valve 14 for switching the suction flow rate. The valves 12, 13, and 14 are three-port solenoid valves provided with SOL1, SOL2, and SOL3 respectively. The A port of the valve 12 is connected to the suction nozzle 8a, the P port and the R port are connected to the A port of the valve 13 and the valve 14 respectively. A port is connected. By switching SOL1 by the control unit 18, the suction nozzle 8a is connected to one of the A port of the valve 13 and the A port of the valve 14.

A pressure sensor 11 is connected to a suction circuit connecting the suction nozzle 8a to the valve 12.
The pressure sensor 11 detects a vacuum pressure in a vacuum suction circuit communicating with the suction nozzle 8a when vacuum suction is performed from the suction nozzle 8a. Therefore, the pressure sensor 11 serves as a vacuum pressure detecting means.

The P port of the valve 13 is connected to an air supply source 15. The SOL 2 is controlled by a control unit 18 to switch the valve 13 so that the P port and the A port communicate with each other. Communicates with the P port. At this time, the A port and the P
By connecting the ports, air blowing is performed from the suction nozzle 8a.

The P port of the valve 14 has a variable throttle 16
, And the R port is directly connected to the vacuum suction source 17. SOL3 to control unit 18
By driving the vacuum suction source 17 in a state where the R port and the A port communicate with each other, vacuum suction is performed from the suction nozzle 8a at the maximum suction flow rate. The suction flow rate at this time is the suction flow rate (first suction flow rate) when the chip 4 is suction-held by the suction nozzle 8a during the pickup operation.

When the vacuum suction source 17 is driven in a state where the P port and the A port communicate with each other, vacuum suction is performed from the suction nozzle 8a at a suction flow rate corresponding to the opening degree of the variable throttle 16. That is, by adjusting the variable aperture 16,
The suction flow rate of vacuum suction from the suction nozzle 8a can be set arbitrarily. As will be described later, this suction flow rate
This is a suction flow rate (second suction flow rate) for determining a suction state for determining whether or not the chip 4 is correctly suctioned by the suction nozzle 8a.

This semiconductor chip transfer device is configured as described above, and the pick-up operation of the semiconductor chip will be described below with reference to the time chart of FIG.
FIG. 2 shows a transfer head operation (movement of the suction nozzle 8a) during pick-up operation of the chip 4 by the transfer head 8 in the chip supply unit 1, suction / blow switching by the valve 12, switching of suction flow by the valve 14, 3 shows the relationship between the respective timings and the detection result of the pressure sensor 11 in this suction operation, that is, the head vacuum pressure indicating the vacuum pressure in the suction nozzle 8a. At the start of the pickup operation, the suction nozzle 8a is at the raised position, the valve 12 is switched to the suction side (the valve 14 side), and the suction flow rate is the first suction flow rate for holding the chip 4 by suction. Has been switched to.

When the pickup operation is started, the suction nozzle 8a first descends, and the lower end of the suction nozzle 8a contacts the upper surface of the chip 4 (timing t1). As a result, the vacuum pressure of the head inside the suction nozzle 8a is changed from the vacuum pressure P1 when suction is performed at the first suction flow rate in a state where no suction is performed on the suction nozzle 8a, so that the suction nozzle 8a comes into contact with the chip 4. As a result, the degree of vacuum is increased to a higher degree of vacuum P2 by an amount corresponding to the increased degree of vacuum.

Here, the direction in which the pressure is reduced and the degree of vacuum is increased is defined as an increasing side (upward arrow side), and the direction in which the pressure is increased is defined as a decreasing side. That is, vacuum suction is performed while the lower end of the suction nozzle 8a is closed by the chip 4, thereby increasing the head vacuum pressure, and reducing the head vacuum pressure when air is sucked from the tip of the suction nozzle 8a.

Thereafter, the suction nozzle 8a starts rising after a predetermined suction time has elapsed from the timing t1, and reaches the rising position at the timing t2. Then, at this timing t2, the valve 14 is switched, and the suction flow rate from the suction nozzle 8a is switched to the second suction flow rate smaller than the first suction flow rate. As a result, the head vacuum pressure decreases from the above-described P2 to a lower vacuum degree P3 by a decrease due to the decrease in the suction flow rate. Vacuum pressure P at this time
Reference numeral 3 denotes a vacuum pressure sufficient for holding the chip 4 by the suction nozzle 8a.

In this state, the suction state is determined based on the result of the vacuum pressure detection by the pressure sensor 11. That is, when the chip 4 is normally suction-held by the suction nozzle 8a, the vacuum pressure detection value indicates the above-described vacuum pressure P3 after a predetermined measurement time has elapsed, as shown in FIG.

On the other hand, the vacuum pressure detection result when the chip 4 is not suctioned, or when the suction state is abnormal such that a vacuum leak occurs due to a large displacement even if the chip 4 is suctioned, is shown in FIG. As indicated by the broken line in the graph of the head vacuum pressure, the detected value moves downward after the suction flow rate is switched. This is because the decrease in the suction flow rate increases the absolute pressure in the suction nozzle 8a. That is, in this case, the vacuum pressure after the elapse of the predetermined measurement time indicates a vacuum pressure P4 lower than the above-described vacuum pressure P3.

Therefore, the threshold value TH is set between these vacuum pressures P3 and P4, and in the pickup operation of the chip 4, the vacuum pressure detection result after a predetermined measurement time elapses after the suction nozzle 8a rises. By comparing with the value TH, it can be determined whether or not the chip 4 is normally sucked and held. Since the suction flow rate is switched to the second suction flow rate which is smaller than the first suction flow rate set for suction holding in the detection of the suction state, the suction state is performed at the suction flow rate for suction holding. Compared with the conventional method of detecting the adsorption state as it is,
Difference Δ in vacuum pressure detection value between normal suction and abnormal suction
P can be made larger and normal / abnormal separation can be performed more accurately.

Conventionally, the suction state is determined in a state where the suction is performed at a large suction flow rate set so as to secure a sufficient suction force for holding the suction. For this reason, as shown in the conventional head vacuum pressure detection result of FIG. 2B, the difference ΔP ′ in the vacuum pressure detection value between the normal suction and the abnormal time is small. It could not be separated, making accurate determination difficult.

On the other hand, in the present embodiment, it is possible to arbitrarily set an appropriate suction flow rate (second suction flow rate) for detecting the suction state according to the size of the suction nozzle 8a by adjusting the variable aperture 16. It is possible to increase the difference between the vacuum pressure detection values depending on the presence or absence of workpiece suction,
Even when a small chip is targeted, it is possible to correctly determine the suction state.

[0029]

According to the present invention, the flow rate switching means for switching the suction flow rate of the vacuum suction means for vacuum suction from the suction nozzle from the first suction flow rate for vacuum suction to the second suction flow rate for detecting the suction state is provided. Since the suction state of the minute work to the suction nozzle is determined based on the vacuum pressure detection result when suction is performed at the second suction flow rate, the difference in the vacuum pressure detection value depending on the presence or absence of work suction is increased. Therefore, even when a small-diameter nozzle is used, the suction state can be correctly determined based on the vacuum pressure.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a semiconductor chip transfer device according to an embodiment of the present invention;

FIG. 2 is a timing chart of a semiconductor chip pickup operation by the semiconductor chip transfer device according to one embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 4 (Semiconductor) chip 8 Transfer head 8a Suction nozzle 11 Pressure sensor 12, 13, 14 Valve 16 Variable throttle 17 Vacuum suction source 18 Control unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C007 AS24 DS01 FS01 FU04 5F031 CA13 GA23 JA21 JA22 JA45 JA47 MA40 5F047 FA08

Claims (4)

[Claims] An apparatus for transferring a small work, which picks up a small work by vacuum suction and transfers the work to a predetermined position, comprising: a suction nozzle which abuts on the small work to suck and hold the fine work; Vacuum suction means for vacuum suction from the nozzle, a first suction flow rate set as a suction flow rate for suction holding for the suction flow rate of the vacuum suction means, and a second suction flow rate set as a suction flow rate for suction state detection Flow rate switching means for switching between suction pressure, vacuum pressure detection means for detecting a vacuum pressure of a vacuum suction circuit connected to a suction nozzle, and vacuum pressure detection by the vacuum pressure detection means when suction is performed at the second suction flow rate An apparatus for transferring a small work, comprising: a suction state determining means for determining a suction state of the small work to the suction nozzle based on a result. 2. The apparatus according to claim 1, wherein the second suction flow rate is smaller than the first suction flow rate. 3. A method for transferring a minute work, wherein the minute work is picked up by vacuum suction and transferred to a predetermined position. A step of sucking and holding the minute work by the suction nozzle by vacuum suction at a first suction flow rate set as a suction flow rate, and a second step of setting the suction flow rate of the vacuum suction means as a suction flow rate for suction state detection. Switching to the suction flow rate, detecting the vacuum pressure of the vacuum suction circuit connected to the suction nozzle when suction is performed at the second suction flow rate, and transferring the minute work to the suction nozzle based on the vacuum pressure detection result. A step of determining a suction state. 4. The method according to claim 3, wherein the second suction flow rate is smaller than the first suction flow rate.