JP3956636B2 - Microwork transfer device and transfer method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microworkpiece transfer apparatus and transfer method for picking up and transferring a microworkpiece such as a small semiconductor chip.
[0002]
[Prior art]
In the manufacturing process of a semiconductor device, a transfer device that picks up a workpiece such as a semiconductor chip and mounts it on a predetermined position is often used. In this transfer apparatus, a method using vacuum suction is widely used as a method for sucking a workpiece. After the workpiece is sucked and held by vacuum suction, the suction state determination is performed to check whether or not the workpiece is sucked in a correct state. This suction state determination generally uses a method of detecting the presence or absence of a workpiece 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, or the like. This vacuum pressure method uses the fact that the degree of vacuum in the vacuum suction circuit rises when the work is attracted, and detects the presence of the work and the quality of the suction state by detecting this degree of vacuum. It is.
[0003]
[Problems to be solved by the invention]
However, with the miniaturization of workpieces, the following difficulties have arisen in workpiece detection by the above detection method. That is, in the method of detecting a workpiece with an optical sensor, it is difficult to distinguish between the suction nozzle and the workpiece depending on the surface properties on the back surface of the workpiece, and accurate workpiece detection is difficult. Further, in the method of detecting the degree of vacuum in the suction nozzle, it is difficult to determine the suction state due to the use of a small nozzle having a small suction hole diameter when a minute work is targeted.
[0004]
That is, since the pressure loss at the time of vacuum suction is large in the small-diameter nozzle, there is no great difference between the degree of vacuum in the suction nozzle when the chip is sucked and the degree of vacuum when the chip is not sucked. . In comparison with the suction capacity of the suction means for vacuum suction of the suction nozzle, the amount of suction air sucked from the small-diameter suction hole in the absence of the work and the work and suction nozzle in the state where the work is sucked and held. This is because there is no significant difference between the amount of air sucked in due to a leak between the two.
[0005]
As described above, the conventional microworkpiece transfer apparatus has a problem in that it cannot accurately determine the quality of the suction state after the pickup operation, and cannot perform a stable transfer operation.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a microworkpiece transfer apparatus and transfer method that can accurately determine the quality of an attracted state for a microworkpiece and perform a stable transfer operation.
[0007]
[Means for Solving the Problems]
The microwork transfer apparatus according to claim 1 is a microwork transfer apparatus that picks up a microwork by vacuum suction and transfers it to a predetermined position. The suction nozzle to be held, the vacuum suction means for vacuum suction from this suction nozzle, the first suction flow rate set as the suction flow rate for suction holding, and the first suction flow rate. A flow rate switching means for switching between a second suction flow rate set as a suction flow rate for suction state detection in a state where a minute work is sucked and held, and a vacuum for detecting the vacuum pressure of a vacuum suction circuit communicating with the suction nozzle Suction for determining a suction state of a minute work on a suction nozzle based on a pressure detection means and a vacuum pressure detection result by the vacuum pressure detection means when sucked at the second suction flow rate And a state determining means.
[0008]
According to a second aspect of the present invention, there is provided the fine workpiece transfer apparatus according to the first aspect, wherein the second suction flow rate is smaller than the first suction flow rate.
[0009]
The method for transferring a micro work according to claim 3 is a method for transferring a micro work by picking up the micro work by vacuum suction and transferring it to a predetermined position, with the suction nozzle in contact with the micro work. A process of sucking and holding a micro work on the suction nozzle by vacuum suction from the suction nozzle at a first suction flow rate set as a suction flow for suction and holding, and holding the micro work by suction and holding at the first suction flow rate A step of 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 in a state, and a vacuum of a vacuum suction circuit communicating with the suction nozzle when suctioned at the second suction flow rate A step of detecting the pressure, and a step of determining a suction state of the minute work to the suction nozzle based on the vacuum pressure detection result.
[0010]
According to a fourth aspect of the present invention, there is provided the method for transferring a micro work according to the third aspect, wherein the second suction flow rate is smaller than the first suction flow rate.
[0011]
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 suction state detection is provided, By determining the suction state of a minute work to the suction nozzle based on the detection result of the vacuum pressure when sucked at the suction flow rate, the suction state is correctly determined by the vacuum pressure even when using a small-diameter nozzle. Can do.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a semiconductor chip transfer apparatus according to an embodiment of the present invention, and FIG. 2 is a timing chart of a semiconductor chip pickup operation by the semiconductor chip transfer apparatus according to an embodiment of the present invention. It is.
[0013]
First, the configuration of a semiconductor chip transfer device as a transfer device for transferring a semiconductor chip, which is a micro work, to a substrate will be described with reference to FIG. In FIG. 1, a chip supply unit 1 includes a wafer holding table 2 that is moved by an XY table (not shown). A wafer sheet 3 on which a large number of semiconductor chips 4 (hereinafter simply abbreviated as “chips 4”) are attached in a predetermined pattern is mounted on the wafer holding table 2. An ejector unit 5 is disposed below the wafer holding table 2. The pin 5a of the ejector unit 5 is aligned with the pickup position of the chip 4 by the transfer head 8, and the chip 4 on the wafer sheet 3 is pushed up by protruding the pin 5a upward.
[0014]
A head moving unit 6 is disposed 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. The transfer head 8 can be moved horizontally by the moving table 7, and the chip 4 pushed up by the pin 5 a is picked up by vacuum suction by the suction nozzle 8 a of the transfer head 8. The picked up chip 4 is moved by the moving table 7 and mounted on the substrate 10 placed on the holding table 9.
[0015]
Next, a control system of the transfer device for the chip 4 and a vacuum suction system for vacuum suction of the suction nozzle 8a will be described. The suction nozzle 8 a is connected to an air blow on / off valve 13 and a suction flow rate switching valve 14 via a suction / blow switching valve 12. The valves 12, 13 and 14 are three-port solenoid valves having SOL 1, 2 and 3, respectively. The A port of the valve 12 is the suction nozzle 8a, the P port and the R port are the A port of the valve 13, and the valve 14 respectively. Connected to the A port. By switching SOL1 by the control unit 18, the suction nozzle 8a is connected to either the A port of the valve 13 or the A port of the valve 14.
[0016]
A pressure sensor 11 is connected to a suction circuit that connects the suction nozzle 8 a to the valve 12. The pressure sensor 11 detects the vacuum pressure in the vacuum suction circuit communicating with the suction nozzle 8a when vacuum suction is performed from the suction nozzle 8a. Therefore, the pressure sensor 11 is a vacuum pressure detecting means.
[0017]
The P port of the valve 13 is connected to the air supply source 15, and the air supply source 15 is connected to the P port of the valve 12 by controlling the SOL 2 by the control unit 18 and switching the valve 13 to connect the P port and the A port. Communicate with. At this time, air is blown from the suction nozzle 8a by connecting the A port and the P port in the valve 12.
[0018]
The P port of the valve 14 is connected to the vacuum suction source 17 via the variable throttle 16, and the R port is directly connected to the vacuum suction source 17. By controlling the SOL3 by the control unit 18 and driving the vacuum suction source 17 in a state where the R port and the A port are in communication, 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 sucked and held by the suction nozzle 8a during the pickup operation.
[0019]
Further, when the vacuum suction source 17 is driven in a state where the P port and the A port are in communication, vacuum suction is performed from the suction nozzle 8 a at a suction flow rate corresponding to the opening of the variable throttle 16. That is, by adjusting the variable throttle 16, the suction flow rate vacuumed from the suction nozzle 8a can be arbitrarily set. As will be described later, this suction flow rate is a suction flow for determining the suction state (second suction flow rate) for determining whether or not the chip 4 is correctly sucked by the suction nozzle 8a.
[0020]
The semiconductor chip transfer apparatus is configured as described above, and the semiconductor chip pickup operation will be described below with reference to the time chart of FIG. FIG. 2 shows a transfer head operation (elevating and lowering operation of the suction nozzle 8a), a suction / blow switching by the valve 12, a suction flow rate switching by the valve 14, during the pickup operation of the chip 4 by the transfer head 8 in the chip supply unit 1. The relationship between the respective timings and the detection result by the pressure sensor 11 in this suction operation, that is, the head vacuum pressure indicating the vacuum pressure in the suction nozzle 8a is shown. At the start of the pickup operation, the suction nozzle 8a is in the raised position, the valve 12 is switched to the suction side (valve 14 side), and the suction flow rate is the first suction flow side for suction holding of the chip 4 It is in the state switched to.
[0021]
When the pickup operation is started, the suction nozzle 8a is first lowered, and the lower end portion of the suction nozzle 8a comes into contact with the upper surface of the chip 4 (timing t1). As a result, the head vacuum pressure in the suction nozzle 8a is brought into contact with the chip 4 from the vacuum pressure P1 when sucked at the first suction flow rate in a state where nothing is sucked by the suction nozzle 8a. As a result, the degree of vacuum is increased to a higher degree of vacuum P2 by the increase in degree of vacuum.
[0022]
Here, in the vacuum pressure, the direction in which the pressure decreases and the degree of vacuum increases is defined as the increasing side (upward arrow side), and conversely, the direction in which the pressure increases is defined as the decreasing side. That is, by vacuum suction with the lower end portion of the suction nozzle 8a closed with the chip 4, the head vacuum pressure increases, and when air is sucked from the tip of the suction nozzle 8a, the head vacuum pressure decreases.
[0023]
Thereafter, the suction nozzle 8a starts to rise after a predetermined suction time has elapsed from the timing t1, and reaches the rising position at the timing t2. At this timing t2, the valve 14 is switched while the suction nozzle 8a holds the chip 4 by suction, and the suction flow rate from the suction nozzle 8a is switched to the second suction flow rate that is smaller than the first suction flow rate. As a result, the head vacuum pressure decreases from the above-described P2 to a lower degree of vacuum P3 by a decrease corresponding to a decrease in the suction flow rate. The vacuum pressure P3 at this time is sufficient to hold the chip 4 by the suction nozzle 8a.
[0024]
In this state, the determination of the suction state based on the vacuum pressure detection result by the pressure sensor 11 is performed. That is, when the chip 4 is normally sucked and held by the suction nozzle 8a, the vacuum pressure detection value indicates the aforementioned vacuum pressure P3 as shown in FIG. 2 after a predetermined measurement time has elapsed.
[0025]
On the other hand, the detection result of the vacuum pressure when the chip 4 is not adsorbed or when the adsorbed state is abnormal such that the vacuum is leaked due to the large displacement is shown in FIG. As indicated by the broken line in the graph, the detected value moves downward after switching the suction flow rate. This is because the absolute pressure in the suction nozzle 8a increases as the suction flow rate decreases. That is, in this case, the vacuum pressure after a predetermined measurement time has elapsed shows a vacuum pressure P4 that is lower than the aforementioned vacuum pressure P3.
[0026]
Accordingly, a 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 the elapse of a predetermined measurement time after the suction nozzle 8a is raised is referred to as the threshold value TH. By comparing, it can be determined whether or not the chip 4 is normally sucked and held. In the detection of the suction state, the suction flow rate is switched to the second suction flow rate that is smaller than the first suction flow rate set for suction holding. Compared to the conventional method of detecting the suction state as it is, the difference ΔP in the vacuum pressure detection value that occurs between normal suction and abnormal time can be made larger, and the normal / abnormal distinction can be made more accurately It is possible to do.
[0027]
Conventionally, the suction state determination is performed in a state in which suction is performed at a large suction flow rate set so as to secure a sufficient suction force for suction holding. Therefore, as shown in the conventional head vacuum pressure detection result of FIG. 2B, the difference ΔP ′ in the vacuum pressure detection value generated between the normal suction time and the abnormal time is small, so that normal / abnormal is clear. It was difficult to make an accurate judgment because it could not be divided.
[0028]
On the other hand, in the present embodiment, the suction flow rate (second suction flow rate) for detecting an appropriate suction state can be arbitrarily set according to the size of the suction nozzle 8a by adjusting the variable throttle 16, and this This makes it possible to increase the difference in the detected vacuum pressure value depending on whether or not the workpiece is attracted, so that it is possible to correctly determine the attracting state even when the target is a microchip.
[0029]
【The invention's effect】
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 suction state detection is provided, Based on the vacuum pressure detection result when sucked at the suction flow rate, the suction state of the minute workpiece to the suction nozzle is determined. Therefore, the difference in the vacuum pressure detection value depending on whether or not the workpiece is sucked can be increased. Even when the diameter nozzle is used, the suction state can be correctly determined by 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 of a semiconductor chip pickup operation performed by the semiconductor chip transfer device according to an embodiment of the present invention. Chart [Explanation of symbols]
4 (Semiconductor) Chip 8 Transfer Head 8a Adsorption Nozzle 11 Pressure Sensors 12, 13, 14 Valve 16 Variable Aperture 17 Vacuum Suction Source 18 Control Unit

Claims (4)

A microworkpiece transfer device that picks up a microworkpiece by vacuum suction and transfers it to a predetermined position, wherein the microworkpiece is in contact with the microworkpiece and sucks and holds the microworkpiece, and vacuum suction is performed from the suction nozzle. Vacuum suction means, a first suction flow rate that is set as a suction flow rate for suction and holding of the vacuum suction means, and a suction state detection in a state in which a minute work is sucked and held at the first suction flow rate A flow rate switching means for switching between a second suction flow rate set as a suction flow rate, a vacuum pressure detection means for detecting the vacuum pressure of a vacuum suction circuit communicating with the suction nozzle, and suction with the second suction flow rate And a suction state determination means for determining a suction state of the minute work to the suction nozzle based on the vacuum pressure detection result by the vacuum pressure detection means at the time Transfer device of the small work. 2. The apparatus for transferring a micro workpiece according to claim 1, wherein the second suction flow rate is smaller than the first suction flow rate. This is a method of transferring a micro workpiece by picking up the micro workpiece by vacuum suction and transferring it to a predetermined position. The suction flow is set as a suction flow for suction holding from the suction nozzle while the suction nozzle is in contact with the micro workpiece. A step of sucking and holding a micro work by the suction nozzle by vacuum suction at a first suction flow rate, and a suction flow rate of the vacuum suction means for sucking state detection while the micro work is sucked and held by the first suction flow rate. The step of switching to the second suction flow rate set as the suction flow rate, the step of detecting the vacuum pressure of the vacuum suction circuit communicating with the suction nozzle when suctioned at the second suction flow rate, and the vacuum pressure detection result And a step of determining a suction state of the micro work on the suction nozzle based on the method. 4. The method for transferring a micro work according to claim 3, wherein the second suction flow rate is smaller than the first suction flow rate.

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