JPH05343294A - Contraction projecting exposure apparatus - Google Patents

Abstract

PURPOSE:To prevent a decrease in processing capacity by simultaneously conducting a peripheral exposure of a wafer and an operation of a prealignment. CONSTITUTION:An irradiating unit 6 irradiates a wafer 1 with a light 12 from an optical fiber 10. A CCD sensor 11 is provided at a position opposed to the unit 6 to obtain an output responsive to an amount of a light to be shielded. The unit 6 can detect a position by a linear scale 9. The wafer 1 is held and rotated by a vacuum chuck 2. The chuck 2 and the unit 6 are relatively displaced, and the chuck 2 is moved by X-Y stages 4, 5, thereby simultaneously conducting an operation of a prealignment and a peripheral exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduction projection exposure apparatus, and more particularly to a reduction projection exposure apparatus which detects an orientation flat (hereinafter referred to as OF) of a semiconductor substrate (hereinafter referred to as a wafer) and aligns the semiconductor substrate. ..

[0002]

2. Description of the Related Art Generally, a reduction projection exposure apparatus pre-aligns a wafer before exposure. When the wafer is carried into the OF alignment section, the wafer is rotated, and the OF is detected by using, for example, a red LED light source, and the wafer is aligned to a predetermined position. After that, press the wafer against the positioning pins,
It was accurately aligned and conveyed to the exposure stage.

However, a new problem has arisen here.
If there is a resist on the peripheral portion or edge of the semiconductor substrate coated with the resist, the resist is peeled off during positioning in a device for performing a process or when it is gripped by a claw during sputtering, and the inside of the device is contaminated. As a method for solving this, there is JP-A-62-286246.

This conventional reduction projection exposure apparatus is shown in FIGS.
As shown in FIG.
When the wafer 16 is carried into the F alignment section and abuts on the wafer positioning roller 19 and the OF positioning roller 18, the position of the wafer 16 is determined.
6 is adsorbed, lifted and rotated to the extent that it does not come into contact with the conveyor belt 20.

Light of the exposure wavelength is guided from the light source 24 of the reduction projection exposure apparatus to the light emitting section 17 by the optical fiber 25, and the light is emitted from the light emitting section 17 toward the peripheral portion and the edge of the wafer 16.

The light emitted from the light emitting portion 17 is light having an exposure wavelength, and if the wafer 16 is rotated while irradiating the wafer 16 with light from the light emitting portion 17, the periphery and edges of the wafer 16 are exposed.

At this time, the light receiving portion 22 is provided below the wafer 16.
Since the OF 16a of the wafer 16 comes to a position facing the light emitting unit 17, and the light receiving unit 22 is covered by the periphery of the wafer 16 other than the OF 16a, the light emitting unit 17 receives light. Since the amount of light reaching the point of is different, the rotational direction position of the OF 16a can be detected from the difference.

In this way, after rotating several times to detect the rotational direction position of the OF 16a while exposing the periphery and the edge, the wafer 16 is placed on the conveyor belt 20 and the OF position is a line connecting the OF positioning rollers 18 to each other. The vacuum chuck 21 stops the suction, and the wafer positioning pin 23 is pressed to press the OF 16a of the wafer 16 against the positioning roller 18 to perform positioning, and then the wafer is conveyed to the exposure stage. ..

As described above, since the peripheral portion of the wafer is exposed, there is an advantage that the resist does not remain on the peripheral portion of the wafer after development and therefore the inside of the apparatus used in the next process is not contaminated.

[0010]

When the resist on the peripheral portion of the wafer is exposed, the resist on the peripheral portion can be removed, but it is necessary to give a specified amount of exposure energy, as in the known example. In the peripheral exposure unit, the illuminance in the peripheral exposure unit is also limited due to device restrictions and the like.

Therefore, the peripheral exposure time, that is, the wafer rotation time is increased to obtain a specified amount of exposure energy. For this reason, in a stepper that does not perform peripheral exposure, it suffices to rotate the wafer only during the rotational position detection time of the OF. There was a case to lower.

Although it is necessary to shorten the time until the completion of pre-alignment as much as possible, in the known example, when the peripheral exposure of the wafer is completed, the vacuum suction is removed and a new pre-alignment is performed by pressing the wafer positioning pin. It took extra time because I had to do some work.

It is an object of the present invention to provide a reduction projection exposure apparatus that performs a peripheral exposure of a wafer and a pre-alignment operation in parallel to prevent a reduction in processing capacity.

[0014]

In order to achieve the above object, a reduction projection exposure apparatus according to the present invention comprises a wafer rotation unit, a biaxial movement mechanism, a wafer rotation position detection mechanism, an irradiation unit and a light receiving unit. , A uniaxial moving mechanism, a light receiving section detecting mechanism,
A reduction projection exposure apparatus having an arithmetic unit, wherein a wafer rotating unit is for adsorbing and rotating a semiconductor substrate, and a biaxial moving mechanism is such that the wafer rotating unit is orthogonal to a plane parallel to the semiconductor substrate. The wafer rotation position detection mechanism detects the rotation angle of the wafer rotation unit, and the irradiation unit and the light reception unit are provided outside the semiconductor substrate on the wafer rotation unit. It is movable in the radial direction of the semiconductor substrate, and the irradiation part is a light source for pattern transfer and is a separate light source for irradiating and exposing the photoresist on the peripheral part and the end face of the semiconductor substrate. It is provided so as to face the peripheral part of the semiconductor substrate with respect to the part, and receives the amount of light according to the amount of the light from the irradiation part blocked by the semiconductor substrate. Part The light-receiving unit detection mechanism detects the position data of the light-receiving unit in the radial direction with respect to the semiconductor substrate on the rotating unit, and the arithmetic unit receives light received by the light-receiving unit as the semiconductor substrate rotates. The function of moving the irradiation unit and the light receiving unit by the uniaxial moving mechanism to the position where the light amount becomes a specified value according to the increase or decrease of the light amount, and executing the exposure by the irradiation unit, and the function of the light receiving unit detection mechanism and the wafer rotation position detection mechanism. Based on the position data, the eccentricity of the semiconductor substrate on the wafer rotating part and the rotational position of the orientation flat of the semiconductor substrate are obtained, and the wafer rotating part is moved in the two axis directions by the two-axis moving mechanism to determine the eccentricity of the semiconductor substrate. A function to perform the pre-alignment of the substrate by correcting the position of the orientation flat by angularly rotating the semiconductor substrate by the wafer rotating unit. It is performed in parallel.

[0015]

By performing the pre-alignment operation and the peripheral exposure operation in parallel, it is possible to prevent a decrease in processing capacity.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
It is the same top view.

In FIG. 1, this unit receives a wafer from a wafer transfer unit (not shown), performs peripheral exposure of the wafer, performs centering of the wafer, and OF positioning of the wafer, and moves it onto an exposure stage via the wafer transfer unit (not shown). The purpose is to supply a wafer.

Referring to FIG. 1, this embodiment shows a vacuum chuck 2 as a wafer rotating unit, an X stage 4 and a Y stage 5 as a biaxial moving mechanism, a wafer rotational position detecting mechanism 3, an irradiation unit 6 and a light receiving unit. CCD sensor 11 as a part
And a motor 8 and a feed screw 7 as a uniaxial moving mechanism,
This is a reduction projection exposure apparatus having a linear scale 9 as a light receiving section detection mechanism and an arithmetic unit 13.

The vacuum chuck 2 as the wafer rotating unit is
It has a motor and sucks and rotates the wafer 1.

XY stages 4 and 5 as a biaxial moving mechanism
Is for moving the vacuum chuck 2 in two axial directions orthogonal to a plane parallel to the wafer 1.

The wafer rotation position detection mechanism 3 is composed of an encoder and detects the rotation angle of the vacuum chuck 2.

The irradiation unit 6 and the light receiving unit 11 are provided outside the wafer 1 on the vacuum chuck 2 and are movable in the radial direction of the wafer 1.

The irradiation unit 6 is composed of a light source different from a light source for pattern transfer which supplies light in an exposure wavelength band for exposing the photoresist on the surface of the wafer 1 through an exposure mask. The photoresist 12 is exposed by irradiating it with light 12 from an optical fiber 10.

The CCD sensor 11 as a light receiving portion is provided so as to face the irradiation portion 6 with the peripheral portion of the semiconductor substrate being sandwiched therebetween, and a light amount corresponding to the amount of light emitted from the irradiation portion 6 blocked by the semiconductor substrate is provided. It receives light.

The uniaxial moving mechanisms 7 and 8 move the irradiation unit 6 and the light receiving unit 11 in the radial direction with respect to the wafer 1 on the vacuum chuck 2 as a wafer rotating unit.

Linear scale 9 as a light receiving unit detecting mechanism
Is for detecting the position data of the light receiving unit 11.

The arithmetic unit 13 uniaxially moves the irradiation unit 6 and the light receiving unit 11 to a position where the light amount reaches a specified value as the amount of light received by the light receiving unit 11 increases or decreases as the semiconductor substrate rotates. On the vacuum chuck 2 as the wafer rotating unit of the wafer 1 based on the position data of the linear scale 9 as the light receiving unit detecting mechanism and the wafer rotation position detecting mechanism 3 and the function of executing the exposure by the irradiating unit 6 by means of The eccentricity of the semiconductor substrate and the rotational position of the OF 15 of the semiconductor substrate are obtained, and the vacuum chuck 2 is moved in the biaxial directions by the XY stages 4 and 5 as a biaxial moving mechanism to correct the eccentricity of the semiconductor substrate and the vacuum chuck 2 Thus, the function of performing the pre-alignment of the substrate for angularly rotating the wafer 1 and correcting the position of the OF 15 is performed in parallel.

Next, a series of operations will be described. The wafer 1 is supplied to the vacuum chuck 2 from a wafer transfer unit (not shown).

In this case, since the rotation center of the vacuum chuck 2 and the center of the wafer 1 are not aligned with each other, it is normally several meters.
There is m-order eccentricity.

In the present invention, the exposure of the peripheral portion and the end face of the substrate is started in this state.

That is, based on a command from the arithmetic unit 13, the motor 8 and the feed screw 7 move the irradiation unit 6 to the peripheral region and the end face of the wafer 1 to the exposure region. on the other hand,
The vacuum chuck 2 rotates the wafer 1 at a constant rotation.

In this case, the rotation center of the vacuum chuck 2 and
Since the center of the wafer 1 is eccentric, the amount of light received by the CCD sensor 11 increases or decreases as the wafer 1 rotates.

Therefore, the arithmetic unit 13 is located at a position where the light quantity at the CCD sensor 11 becomes a specified value based on the output of the CCD sensor 11, that is, at a position where the irradiation range of the irradiation unit 6 matches the exposure area 14 of FIG. Irradiation unit 6
Is moved by the motor 8 and the feed screw 7 to perform the exposure by the irradiation unit 6.

At the same time, the arithmetic unit 13 is connected to the encoder 3
The output of the linear scale 9 is stored in synchronism with the output of the wafer, and the result is calculated to obtain the eccentricity of the wafer 1 and O
The position of F15 is detected.

Then, the arithmetic unit 13 corrects the eccentricity of the center of the wafer 1 on the vacuum chuck 2 by the XY stages 4 and 5, and also causes the wafer 1 to be moved by the vacuum chuck 2.
Is rotated to correct the position of OF15. Pre-alignment of the wafer 1 is completed here.

Here, the wafer 1 is first removed from the vacuum chuck 2, and then the wafer 1 is supplied onto the exposure stage by a wafer transfer unit (not shown).

The peripheral exposure area 14 is exposed by the above operation. Further, the position detection of the OF15 and the calculation of the eccentricity amount are
It can be done during the rotation of the wafer, that is, during the edge exposure,
The pre-alignment can be completed at the same time when the peripheral exposure is completed without the need to remove the suction of the wafer once.

In the above-described embodiment, the peripheral exposure unit is moved with respect to the amount of eccentricity of the wafer to perform peripheral exposure at an appropriate position on the periphery of the wafer.
You can also perform peripheral exposure while moving the.

In this case, since it is not necessary to provide a servomotor on the side of the peripheral exposure unit, the structure and movement of the apparatus can be simplified, and stable peripheral exposure can be performed without vibration of the peripheral exposure unit.

[0040]

As described above, according to the present invention, since the pre-alignment operation by pressing the wafer after the peripheral exposure is eliminated, the time until the completion of the pre-alignment can be shortened and the processing capability of the stepper can be improved.

Moreover, since the resist around the wafer can be removed, there is an excellent effect that the inside of the apparatus is not contaminated with the resist.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a plan view showing a conventional example.

FIG. 4 is a side view of the same.

[Explanation of symbols]

 1 Semiconductor substrate (wafer) 2 Vacuum chuck 3 Encoder 4 X stage 5 Y stage 6 Irradiation part 7 Feed screw 8 Motor 9 Linear scale 10 Optical fiber 11 CCD sensor 12 Light 13 Arithmetic unit 14 Peripheral exposure area 15 Orientation flat (OF)

Claims (1)

[Claims] 1. A reduction projection exposure apparatus having a wafer rotating unit, a biaxial moving mechanism, a wafer rotational position detecting mechanism, an irradiating unit and a light receiving unit, a uniaxial moving mechanism, a light receiving unit detecting mechanism, and an arithmetic unit. The wafer rotating unit is for adsorbing and rotating the semiconductor substrate, and the biaxial moving mechanism is for moving the wafer rotating unit in the biaxial directions orthogonal to the plane parallel to the semiconductor substrate. The wafer rotation position detection mechanism detects the rotation angle of the wafer rotation unit. The irradiation unit and the light receiving unit are provided outside the semiconductor substrate on the wafer rotation unit and move in the radial direction of the semiconductor substrate. The irradiation unit is a light source for pattern transfer and is a separate light source that irradiates and exposes the photoresist on the peripheral portion of the semiconductor substrate and the end surface. Clap It is provided so as to face each other, and receives a light amount corresponding to the amount of light emitted from the irradiation unit blocked by the semiconductor substrate.The uniaxial movement mechanism moves the irradiation unit and the light receiving unit relative to the semiconductor substrate on the wafer rotating unit. The light receiving unit detection mechanism detects the position data of the light receiving unit, and the arithmetic unit operates in accordance with an increase or decrease in the amount of light received by the light receiving unit as the semiconductor substrate rotates. The function of moving the irradiation unit and the light receiving unit to the position where the light amount becomes the specified value by the uniaxial moving mechanism to execute the exposure by the irradiation unit, and the position of the semiconductor substrate of the semiconductor substrate based on the position data of the light receiving unit detection mechanism and the wafer rotation position detection mechanism. The eccentricity on the wafer rotating part and the rotation position of the orientation flat of the semiconductor substrate are obtained, and the wafer rotating part is moved in the biaxial directions by the biaxial moving mechanism to correct the eccentricity of the semiconductor substrate. Together, a reduction projection exposure apparatus, characterized in that is performed in parallel and a function of executing the pre-alignment of the substrate for correcting the position of the orientation flat of the semiconductor substrate is angularly rotated by the wafer rotating unit.