KR100219803B1 - Intensity check apparatus of interferemeter of exposure apparatus - Google Patents

Abstract

An interferometer light amount check apparatus of an exposure apparatus improved to perform an alarm operation by checking the light amount of a laser provided from an interferometer used for movement control of a stage.

The present invention relates to an interferometer light quantity check of an exposure apparatus for controlling the driving of the stage by using the respective light reflected from the first and second mirrors to which the laser scanned from the interferometer is attached to the two-dimensional X and Y sidewalls of the stage. An apparatus, comprising: first and second receivers for receiving light reflected from the first and second mirrors, respectively, and outputting first and second comparison voltages proportional to the amount of light received, the first and second comparison voltages And a switching means for generating an error signal by judging the output of the first and second comparator and comparing the first and second comparator with each other.

Therefore, the exposure facility is detected by the abnormal alignment and control state due to the laser sensitivity is reduced, the efficiency of facility management is improved, the generation of defective wafers is prevented, the yield is maximized.

Description

Interferometer light quantity check device of exposure equipment

The present invention relates to an interferometer light quantity check apparatus of an exposure apparatus, and more particularly, to an interferometer light quantity check apparatus of an exposure apparatus that is improved to perform an alarm operation by checking the light quantity of a laser provided from an interferometer used for controlling movement of a stage. It is about.

In general, a wafer for manufacturing a semiconductor device is repeatedly subjected to processes such as cleaning, diffusion, photography, etching, and ion implantation, and then manufactured into a finished product through a packaging process or the like.

Among the above-described processes, a photo process is a process of forming a pattern on a wafer, and is a process of forming an image of a reticle on a wafer by using a photosensitive material. Can be.

In the exposure apparatus for performing exposure among the above-described steps, the process result depends on the alignment state of the wafer. Usually, a specific patterned key is formed on the wafer surface for alignment or a reference mark is formed on the stage.

Control of the position to be exposed during the exposure process is performed by moving the stage in the X-axis and Y-axis directions after the wafer is loaded into the stage, and the amount of movement of the stage is measured using a laser of an interferometer, The movement is controlled.

Mirrors are attached to two sidewalls of the two-dimensional X-direction and Y-direction of the conventional stage, and the laser provided from the interferometer passes through the reflectometer and proceeds to each mirror, and the light reflected by each mirror is It is received at the receiver again via a reflectometer.

The receiver counts the wavelength of the received light, and the change in the counted wavelength is used for the movement of the stage. This is the application of the Doppler effect. The wavelength of the received laser is changed according to the state in which the stage is moved back and forth, and the movement of the stage can be precisely controlled to a range of several μm using the detected result.

However, the light source configured to generate the laser in the interferometer deteriorates according to the accumulation degree of the application time, and accordingly, the voltage detected in the receiving section receiving the reflected wave of the laser decreases.

As described above, when the voltage received by the receiver drops and falls below a predetermined level (about 7V or less), an abnormal operation such as an interrupt occurs for exposure of the wafer is performed. Thus, the conventional exposure apparatus did not normally perform exposure of the wafer. . That is, a defective wafer was partially generated in which the exposure of the pattern was not performed.

In addition, since the reception sensitivity of the receiver decreases as the laser becomes weak, it is difficult to accurately measure the stage using the reflective laser, resulting in misalignment on the wafer.

As a result, the conventional exposure equipment is not detected abnormal alignment and control state, the efficiency of facility management is lowered, there is a problem that the yield is reduced because a large amount of defective wafers are produced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an interferometer light quantity checking apparatus of an exposure apparatus for checking whether a voltage level falls below a predetermined value by checking a reception voltage level of a laser reflected from a stage moved to perform exposure of a wafer. There is.

1 is a diagram showing an embodiment of an interferometer light quantity check apparatus of an exposure apparatus according to the present invention.

※ Explanation of symbols for main parts of drawing

10: stage 12, 14: mirror

16: interferometer 18, 20: reflector

22, 24: receiver 26, 28: comparator

30: constant voltage circuit 32: oragate

34: relay 36: alarm unit

VR1, VR2: Variable resistor Q1: Transistor

R1: resistor D1: diode

C1, C2: Capacitor

The interferometer light quantity checking device of the exposure apparatus according to the present invention for achieving the above object is to detect each light reflected by the first and second mirrors, the laser scanning from the interferometer is attached to the side walls of the two-dimensional X and Y direction of the stage An interferometer light quantity checking device of an exposure apparatus that controls driving of the stage by using the light source, wherein the light reflected from the first and second mirrors is respectively received to output first and second comparison voltages proportional to the received light quantity. Determining the outputs of the first and second receivers, the first and second comparators for comparing the first and second comparison voltages with a reference voltage of a predetermined level or less, and the first and second comparators, respectively, And switching means for generating a signal.

The first and second variable resistors are connected to the first and second comparators, respectively, and configured to separately set the respective reference voltages. The constant voltage outputs a reference voltage of a predetermined level with an input voltage of a predetermined level. Preferably, the circuit is further configured to apply the reference voltage to the first and second comparators.

In addition, the switching means may be composed of a logic combining means for combining the outputs of the first and second comparator and the relay means for outputting the error signal by being interlocked according to the output signal state of the logic combining means. The relay means may include a switching element switched to the output of the logic combination means and a relay interlocked with the switching element.

And an alarm means for performing an alarm operation by receiving an error signal output from the switching means, wherein the alarm means performs an interrupt operation on an exposure operation when an error signal is applied, or emits light or pronounces an operation. It can be configured to perform.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to Fig. 1, in the embodiment according to the present invention, mirrors 12 and 14 are attached to sidewalls of two-dimensional X and Y directions of a stage 10 on which a wafer is loaded, and a light source (not shown). The interferometer 16 is configured to supply the laser generated from the light source, and the reflecting plates 18 and 20 are configured to reflect the laser beam from the interferometer 16 and proceed to the mirrors 12 and 14, respectively. 22 and 24 are configured to receive the lasers reflected from the mirrors 12 and 14, respectively.

Each of the receivers 22 and 24 counts the wavelength of the incident laser and outputs the wavelength to the exposure operation control unit (not shown), while inverting the comparator 26 and 28 with a voltage proportional to the amount of light received from the laser. It is configured to apply to (-).

Variable resistors VR1 and VR2 are connected to the non-inverting terminals (+) of each of the comparators 26 and 28 such that a constant voltage having a stable level is applied through the constant voltage circuit 30, and applied to the variable resistors VR1 and VR2. Capacitors C1 and C2 for smoothing the reference voltages are connected in parallel.

Here, the constant voltage circuit 30 is configured to stabilize the voltage Vs applied at a predetermined level and to use the reference voltage of the comparators 26 and 28.

Meanwhile, the outputs of the comparators 26 and 28 are applied to the input terminal of the oragate 32, and the output of the oragate 32 is applied to the base of the transistor Q1 through the resistor R1. The transistor Q1 is connected to the driving terminal of the relay 34 in which the counter electromotive force diode D1 is installed, and the alarm unit 36 is connected to the switching terminal of the relay 34.

Therefore, the mirrors 12 and 14 attached to the stage 10 during the exposure process reflect the lasers provided from the interferometer 16 through the reflectometers 18 and 20, respectively, and the lasers reflected by the receivers 22, 24).

The receivers 22 and 24 sense the received laser and convert it into a voltage proportional to the amount of light thereof, and the detection voltages of the lasers received by the receivers 22 and 24 are applied to the inverting ends of the comparators 26 and 28. .

At this time, the reference voltage applied to the non-inverting ends of the comparators 26 and 28 is set to about 7V to 8V, and the comparators 26 and 28 compare whether the voltage level applied to the inverting end is equal to or higher than the reference voltage level. The comparators 26 and 28 output a low level logic signal when the voltage level applied to the inverting stage is equal to or higher than the reference voltage, and outputs a high level logic signal when the voltage level is higher than the reference voltage.

When each of the comparators 26 and 28 outputs a logic signal at a low level, the amount of laser light provided from the interferometer 16 is such that a level at which the exposure process can be performed is performed. On the contrary, each of the comparators 26 and 28 is a logic signal. Is output at a high level, the amount of light emitted from the interferometer 16 is such that the exposure process cannot be performed.

The exposure process can be normally performed and the movement of the stage 10 can be normally controlled only when the amount of light of the reflected lasers in the X direction and the Y direction received by each of the receivers 22 and 24 is maintained at a normal level.

However, when the amount of light of the laser received at either of the receivers 22 and 24 is less than or equal to the predetermined level set as the reference voltage, the high level output is applied to the input terminal of the oragate 32, so that the oragate 32 is A high level voltage is applied to the transistor Q1 through the resistor R1, and accordingly, the transistor Q1 is turned on, and the relay 34 is interlocked to output an error signal to the alarm unit 36.

The alarm unit 36 may perform various alarm operations by the bar according to the intention of the manufacturer.

That is, when an alarm unit is provided in the exposure operation control means, an error signal is applied to the exposure operation so that the exposure operation is interrupted. Then, the generation of the defective wafer in which the exposure of the pattern is not partially performed is stopped.

When the alarm unit is configured as a light emitting device or a sounding device, an operator can recognize an error situation by a light emitting operation or a sounding operation and take immediate action accordingly, so that the facility is efficiently managed and generation of a defective wafer is stopped.

Therefore, the exposure facility is detected by the abnormal alignment and control state due to the laser sensitivity is reduced, the efficiency of facility management is improved, the generation of defective wafers is prevented, the yield is maximized.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (9)

An interferometer light quantity check apparatus of an exposure apparatus for controlling the driving of the stage by using the light reflected from the first and second mirrors, which are scanned by the interferometer, on the sidewalls of the two-dimensional X and Y directions of the stage. First and second receivers receiving light reflected from the first and second mirrors, respectively, and outputting first and second comparison voltages proportional to the amount of light received; First and second comparison units for comparing whether the first and second comparison voltages are equal to or less than a reference voltage of a predetermined level; And Switching means for generating an error signal by determining outputs of the first and second comparators; Interferometer light amount check apparatus of an exposure facility comprising the. The method of claim 1, And a first and second variable resistors connected to the first and second comparators, respectively, to separately set the respective reference voltages. The method of claim 1, And a constant voltage circuit for outputting a reference voltage of a predetermined level at an input voltage of a predetermined level, so that the reference voltage is applied to the first and second comparators. The method of claim 1, wherein the switching means; Logical combining means for combining and combining the outputs of the first and second comparing units; And Relay means for outputting the error signal by being interlocked and switched according to the output signal state of the logic combining means; Interferometer light quantity check device of the exposure facility characterized in that it comprises a. The method of claim 4, wherein the relay means; A switching element switched to an output of the logic combining means; And A relay interlocked with the switching element; Interferometer light amount checking device of the exposure equipment characterized in that it comprises a. The method of claim 1, And an alarm means for receiving an error signal output from the switching means to perform an alarm operation. The method of claim 6, And said alarm means is configured to perform an interrupt in the exposure operation when an error signal is applied. The method of claim 6, And said alarm means is configured to perform a light emitting operation when an error signal is applied. The method of claim 6, And said alarm means is configured to perform a pronunciation operation when an error signal is applied.