KR20010018066A - An apparatus for sensing wafer - Google Patents

Abstract

PURPOSE: An apparatus for sensing a wafer is provided to prevent damage to a wafer, by having two different wafer not loaded on a wafer stage, simultaneously. CONSTITUTION: The first photo sensor(100) senses whether a wafer(16) exists, and accordingly outputs the first and second signals, installed in a process chamber(10). The second photo sensor(101) senses whether the wafer exists, and accordingly outputs the first and second signals, installed in a wafer stage(12). A control unit(102) controls an operation of a transfer arm(15) according to the signals outputted from the fist and second photo sensors, connected to the first and second photo sensors.

Description

An wafer for sensing wafer

The present invention is a wafer sensing device, and more particularly, a wafer sensing device that automatically detects whether a wafer being transferred by a transfer arm unit is located at a process chamber and a wafer stage, and thus prevents wafers from being overlapped and damaged. .

Generally, deposition, exposure, and etching processes are performed to produce semiconductor devices. In this manufacturing process, wafers are generally loaded from a wafer stage into a process chamber to proceed with the process. As unloading, a process of manufacturing a semiconductor device is performed by continuously performing a process of loading and unloading a new wafer into a process chamber.

FIG. 1 is a view for explaining wafer position detection in a process chamber and a wafer stage used in a manufacturing process of a semiconductor device, and a wafer chuck for mounting a wafer 16 in a process chamber 10 in which a semiconductor manufacturing process is performed. 11), the wafer chuck 11 is connected to a vacuum pump (13).

In the process chamber 10, there is a wafer stage 12 for measuring the wafer, in which the process is completed, and the wafer 16 is unloaded. The wafer stage 12 is also connected to the vacuum pump 14. have.

Then, there is a transfer arm 15 for unloading the wafer 16 of the process chamber 10 into the wafer stage 12.

The position detection of the wafer configured as described above, when the process is completed on the wafer on which the vacuum pump 13 of the wafer chuck 11 is vacuum-adsorbed, the transfer arm 15 moves the wafer 16 to the wafer stage 12. Unload

The wafer unloaded to the wafer stage 12 is subjected to a wafer inspection by vacuum suction of the back surface of the vacuum pump 14.

When the inspection of the wafer is completed in the wafer stage 12, the wafer is unloaded out of the wafer stage 12 by a separate transfer arm part (not shown).

At this time, the wafer position of the wafer stage 12 is determined by the vacuum suction force of the vacuum pump 14.

That is, when the wafer 16 is unloaded to the wafer stage 12 and the vacuum pump 14 vacuum-adsorbs the rear surface of the wafer, the control means (not shown) determines whether the wafer is positioned according to the vacuum sensitivity.

However, if the vacuum sensitivity of the wafer stage is unstable in the process of unloading the wafer into the wafer stage in such a conventional process chamber, the control means does not detect this and, despite the wafer being placed on the wafer stage, another transfer arm is moved to the next transfer arm. There is a problem of loading a wafer.

Thus, two different wafers are unloaded on the wafer stage, resulting in scratching and overlapping of the wafer, which in turn causes damage to the wafer.

Accordingly, an object of the present invention is to provide a wafer sensing device capable of accurately detecting the position of a wafer so that two different wafers are not loaded on a wafer stage.

Therefore, the wafer sensing device of the present invention is a wafer sensing device for determining the presence or absence of a wafer by detecting a wafer transferred to a process chamber and a wafer stage by a transfer arm with a vacuum, and is installed on the process chamber to detect the presence or absence of a wafer. Accordingly, the first photosensor for outputting the first or second signal, the second photosensor installed on the wafer stage to detect the presence of the wafer and accordingly outputs the first or second signal, the first photosensor and And a control unit connected to a second photosensor to control an operation of the transfer arm according to signals output from the first and second photosensors.

Here, the first photosensor and the second photosensor are a light emitting device connected between the operating voltage and the ground voltage, and a photo connected between the operating voltage and the control unit to detect when the light emitted from the light emitting device is reflected by the wafer The transistor is configured to output a first signal when there is no light detected by the photo transistor, and output a second signal when there is light detected by the photo transistor.

The control unit includes an AND gate that performs an AND operation on the output signals of the first and second photo sensors, and an electromagnet connected between the AND gate and the ground voltage, so that a second signal is respectively provided from the first and second photosensors. When output, a magnetic field is generated in the electromagnet to turn off the power switch of the transfer arm.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view for explaining whether a wafer is present in a conventional process chamber and a wafer stage.

2 is a view for explaining a wafer sensing device of the present invention.

3 is a circuit diagram of a wafer sensing device of the present invention.

■ Brief description of the main parts of the drawing ■

10 process chamber 11 wafer chuck

12: wafer stage 13.14: vacuum pump

15 transfer arm portion 16 wafer

100,101: photo sensor 102: control unit

LED 1,2: Light emitting element Tr 1,2: Phototransistor

AND: AND gate SW: power switch

EM: Electromagnet

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention a wafer sensing device as follows.

2 is a view for explaining a wafer sensing device according to the present invention.

The wafer sensing device of the present invention detects a wafer transferred to the process chamber 10 and the wafer stage 12 by a vacuum by the transfer arm unit 15 and determines whether the wafer is present, and is installed on the process chamber 10. The first photosensor 100 for detecting the presence of the wafer and accordingly outputs the first or second signal, and is installed in the wafer stage 12 to detect the presence of the wafer and accordingly outputs the first or second signal A control unit 102 connected to the second photosensor 101 and the first photosensor and the second photosensor to control the operation of the transfer arm unit 15 according to signals output from the first and second photosensors. It further comprises.

In more detail, the first photosensor 100 is installed at the upper end of the process chamber 10 in which the wafer chuck 11 for vacuum suctioning the rear surface of the wafer 16 with the vacuum pump 13 is formed.

The first photosensor 100 continuously emits light, but when the wafer 16 is positioned on the wafer chuck 11, the emitted light is reflected on the surface of the wafer to receive light.

In addition, the second photosensor 101 is installed on the upper end of the wafer stage 12 that vacuum-adsorbs the rear surface of the wafer with the vacuum pump 14 to be spaced a predetermined distance apart.

The second photosensor 101 also emits light continuously in the same manner as the first photosensor 100, but is reflected on the surface of the wafer when the wafer is placed on the wafer stage 12 to receive light.

If the light is emitted from the first photosensor 100 and the second photosensor 101 and the light is not received, the control unit 102 operates the transfer arm unit 15 and the first photosensor 100 and the second photosensor. When light is emitted from the photosensor 101 and received, the operation of the transfer arm 15 is stopped.

Referring to FIG. 3, the first photosensor 100 and the second photosensor 101 may include light emitting devices LED1 and LED2 connected between an operating voltage V_cc and a ground voltage, an operating voltage V_cc and a controller ( Each of the photo transistors Tr1 and Tr2 is connected to each other to detect light emitted from the light emitting device.

Accordingly, the first photosensor 100 and the second photosensor 101 output a first signal (output value '0') when no light is detected by the photo transistors Tr1 and Tr2, and when the light is detected, It outputs 2 signals (output value '1').

In addition, the controller 102 may be an AND gate connected between the phototransistors Tr1 and Tr2 and the ground voltage, and an electromagnet (EM) connected between the AND gate and the ground voltage. When the second signal (output value '1') is respectively output from the photosensor, the electromagnet forms a magnetic field to turn off the power switch SW of the transfer arm 15.

The presence or absence of the wafer is determined by the wafer sensing device having the above configuration.

First, when the wafer is not located in the process chamber 10 and the wafer stage 12, the first photosensor 100 and the second photosensor 101 reflects the light emitted from the light emitting elements LED1 and LED2. Therefore, light is not detected in the phototransistors Tr1 and Tr2.

Therefore, the first and second photosensors transmit the first signal (output value '0') to the AND gate of the controller, respectively, so that the AND gate is not operated.

Therefore, the electromagnet does not form a magnetic field, so that the power switch SW of the transfer arm 15 is kept in an 'on' state, and the wafer is transferred.

In addition, when the wafer is located only in the process chamber 10 of the process chamber 10 and the wafer stage 101, the first photosensor 100 sends a second signal (output value '1') to the end of the control unit 102. The second photo sensor 101 transmits the first signal (output value '0') to the AND gate of the controller 102.

Therefore, the AND gate receives the first signal and the second signal but does not operate, so the electromagnet EM does not form a magnetic field, and the wafer is continuously maintained by turning on the power switch of the transfer arm unit 15 in the 'on' state. The transfer of is made.

At this time, the wafer located in the process chamber 10 is made of the wafer by the vacuum pump 13 at the same time as the detection of the first photosensor 100.

On the contrary, even when the wafer is located only on the wafer stage 12, the wafer is continuously transferred similarly to the case where the wafer is located only on the process chamber 10. FIG.

Finally, when the wafers are positioned in the process chamber 10 and the wafer stage 12, respectively, the first and second photosensors 100 and 101 are both the second gate (output value '1') to the AND gate of the controller 102. Is transmitted to the AND gate of the controller 102.

When the second signal (output value '1') is transmitted to the AND gate of the controller 102, the AND gate performs an AND operation to form a magnetic field in the electromagnet EM.

The magnetic field of the electromagnet switches the power of the transfer arm portion 15 in the on state to the off state to cut off the power of the transfer arm portion 15 so that it is no longer operated.

At this time, the wafers positioned in the process chamber 10 and the wafer stage 12 are simultaneously sensed by their vacuum pumps 13 to 14.

Therefore, the transfer arm 15 is not operated until the wafer on the wafer stage 12 is transferred out of the wafer stage 12 by another transfer arm (not shown), and the wafer of the process chamber 10 Is transferred to the wafer stage 12 to prevent overlapping of the wafer.

If the wafer is not positioned on the wafer stage 12, the AND gate of the control unit 102 is not operated, and the power switch SW of the transfer arm unit 15 is switched back to an 'on' state to transfer the arm. The wafer is transferred by (15).

As described above, the wafer sensing device of the present invention determines the presence or absence of the wafer on the process chamber or the wafer stage by vacuum, and the presence or absence of the wafer by the first and second photosensors determines the operation of the transfer arm portion. By controlling, the presence or absence of the wafer is doubled, and in the state where the wafer is positioned on the wafer stage, another wafer is not transferred from the process chamber to prevent scratches and damage of the wafers generated by overlapping the wafers.

Claims (3)

In the wafer sensing device for detecting the presence of the wafer by detecting the wafer transferred to the process chamber and the wafer stage by a transfer arm, A first photosensor installed on the process chamber to sense the presence of the wafer and to output a first or second signal accordingly; A second photosensor installed on the wafer stage to sense the presence of the wafer and to output a first or second signal accordingly; And a controller connected to the first photosensor and the second photosensor to control an operation of the transfer arm according to signals output from the first and second photosensors. The method according to claim 1, The first photosensor and the second photosensor A light emitting device connected between an operating voltage and a ground voltage; A phototransistor connected between the operating voltage and the controller to detect light emitted from the light emitting element when reflected by the wafer; Outputting a first signal when there is no light detected by the photo transistor, And a second signal is output when there is light detected by the photo transistor. The method according to claim 1, The control unit An AND gate for performing an AND operation on the output signals of the first and second photo sensors; An electromagnet connected between the AND gate and a ground voltage, And a magnetic field is formed in the electromagnet when the second signal is output from the first and second photosensors, respectively, to turn off the power switch of the transfer arm unit.