KR100857986B1 - Device for removing noise - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a noise removing device and a method for removing semiconductor exposure equipment, in which the distribution of light incident on a reticle is uniform, thereby removing noise in the lighting unit and removing diffracted light.

Accordingly, the present invention provides blinds for uniformly irradiating slit-type light emitted from a light source, two condensing lenses for transmitting the light irradiated through the blinds, and light passing through the condensing lenses to form a pattern on the wafer. A semiconductor exposure apparatus having an illumination unit including a reticle, and a projection unit having a projection lens for irradiating light transmitted from the illumination unit onto a wafer, wherein a plurality of polarizing plates having different polarization directions on one surface of the reticle Provided is a noise removing device of a semiconductor exposure apparatus, characterized in that arranged continuously.

Reticle, Polarizer, Opaque, Noise

Description

Noise removing device and method for removing semiconductor exposure equipment

1 is a schematic diagram showing the principle of exposure in a system of exposure equipment.

2 is a schematic cross-sectional view showing a noise removing device of a semiconductor exposure apparatus according to an embodiment of the present invention;

3 is a schematic cross-sectional view showing a lighting unit of the exposure apparatus according to the prior art.

Explanation of symbols on the main parts of the drawings

10, 32: condenser lens 12, 35: reticle

14 projection lens 16 wafer

18, 31: blind 20, 37: mask pattern

40: opaque plate 41: x-axis polarizing plate

42: y-axis polarizer

Ⅰ: Illumination Ⅱ: Projection

A, A ′: conjugate plane

The present invention relates to a semiconductor exposure apparatus, and more particularly, to a noise removing device and a method for removing noise and diffracted light in an illumination unit by uniformly distributing light incident on an upper portion of a reticle.

Conventional exposure methods for overcoming the focal depth limitation of an exposure system include a method using a stepper and a method using a scanner that moves by exposing a wafer stage.

First, a method using a stepper has a disadvantage in that the size of the field that can be exposed is small and the pattern is difficult because the end of the field is outward.

Second, a method using a scanner that moves a wafer stage and exposes it is an exposure method in which multiple stages are obtained by continuously moving the stage parallel to the optical axis during exposure, and a larger field can be obtained. Since it exposes, there is an advantage of obtaining a uniform pattern as a whole.

In general, the lens of the projector exposure equipment generates noise due to the light wandering inside the lens when irradiated. Flare noise in the exposure method using the scanner is slightly different from the conventional stepper.

The scanner device has a blind positioned so as to uniformly illuminate the light emitted from the light source from the light source, and the light emitted from the blind is transmitted through the condensing lens to be irradiated onto the wafer through a reticle in which a mask pattern is formed. do. In this case, when exposing a field in the scanner device, the light is slit-shaped while moving the reticle to continuously move. To increase the uniformity of the light, the center of the light is of the same intensity, but gradually decreases toward the edges, eventually producing a light with a trapezoidal distribution to illuminate the reticle.

There is no countermeasure against flare noise. In addition, the flare noise is a phenomenon in which the light wandering by scattering on the surface of the lens is transferred to the wafer surface in the form of noise.

Lenses used in semiconductors and liquid crystal display devices have dozens of total lens components, so the diffuse reflection noise on the surface acts to reduce the image contrast on the wafer surface.

Hereinafter, the prior art will be described with reference to the accompanying drawings.

1 is a schematic view showing a system of an exposure apparatus according to the prior art, Figure 3 is a schematic cross-sectional view showing the lighting unit of FIG.

The system of scanner equipment is largely divided into illumination part (I) and projection part (II). The lighting unit I includes a condenser lens 10 and a reticle 12, and the projection unit II includes a projection lens 14 and a wafer 16. It is. (See Fig. 1)

Referring to FIG. 3, the lighting unit I includes two or more condensing lenses 10. Two illumination planes having optically the same value as the reticle 12 are formed in the illumination unit I, and are blindly spaced apart from the first copper plane A closest to the light source by 18 degrees. ) To improve the uniformity of light. At this time, since the blind 18 is a distance away from the liquid surface A, light C is generated in a trapezoidal outward direction as shown in the graph of ⓐ at the second liquid surface A '. It also adds flare noise. Accordingly, light having a uniformity, such as a graph of ⓑ, is incident on an undesired portion of the reticle 12, which causes interference with pattern formation.

In addition, since the diffraction phenomenon occurs when the obstacle meets the characteristics of light, trapezoidal noise (B) appears due to the diffraction phenomenon of light, and this noise acts as a deterrent to pattern formation.

In the exposure apparatus according to the prior art as described above, the noise removing method has a uniform distance from the copper liquid surface and the blind, so that the uniformity of the slit-like light is diffused out of the trapezoid to generate noise, and the lens to flare noise is added. There is a problem that the light enters the unwanted portion of the reticle affects the pattern formation.

Accordingly, the present invention has been made to solve the above-mentioned problems, and the noise removing device of the semiconductor exposure equipment that can remove the noise in the illumination unit by removing the noise in the illumination unit by uniformly distributing the light incident on the reticle And a method of removal.

In order to achieve the object as described above, the present invention is that the polarizing plate having a different polarization direction for removing noise due to diffracted light is provided on one surface of the reticle.

To this end, the present invention provides a blind for uniformly irradiating the slit-shaped light irradiated from the light source, two condensing lenses for transmitting the light irradiated through the blind, and a pattern on the wafer by transmitting the light through the condensing lens. A semiconductor exposure apparatus having an illumination unit including a reticle for forming a projection and a projection lens for irradiating light transmitted from the illumination unit onto a wafer, wherein the light is polarized in the y-axis direction on one surface of the reticle. The y-axis polarizing plate to make and the x-axis polarizing plate which polarize light in an x-axis direction are provided continuously.

In addition, the present invention may be installed on the upper surface or the lower surface of the polarizing plate.

In addition, the present invention may be further provided with an opaque plate to remove noise in addition to the polarizing plate.

Here, the noise removing method in the exposure apparatus according to the present invention through the device, a blind for uniformly irradiating the slit-shaped light irradiated from the light source, two condensing lenses for transmitting the light irradiated through the blind, Using a semiconductor exposure apparatus having an illumination unit including a reticle for transmitting light through the condensing lens to form a pattern on a wafer and a projection lens for irradiating light transmitted from the illumination unit onto the wafer In a method of removing noise in an exposure apparatus that exposes a wafer while exposing the wafer while moving the reticle and the wafer at a constant speed, the light is projected through an x-axis polarizer and a y-axis polarizer together with an opaque plate on the reticle. Characterized in that.

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

1 is a schematic view showing a general exposure equipment, Figure 2 is a cross-sectional view showing a noise removing device of the exposure equipment according to an embodiment of the present invention.

According to the above drawings, in the scanner apparatus, which is an exposure apparatus, the illumination unit is provided with two condensing lenses 32 between the reticle 35 and the copper liquid surface A, which is formed closest to the light source. The blind 31 is formed below.

Since the blind 31 is formed to be spaced apart from the copper liquid surface A by a predetermined distance, noise is generated in the light irradiated to the reticle 35 to have a uniformity of light such as?.

In the present invention, the opaque plate 40 is formed on the reticle 35 to prevent the noise from occurring.

In addition, the x-axis polarizing plate 41 for polarizing the diffracted light generated by the diffraction phenomenon of the light in the x-axis direction and the diffracted light generated by the diffraction phenomenon of the light in the y-axis direction below the opaque plate 40 The y-axis polarizing plate 42 is arranged at a reverse speed.

Accordingly, the light is polarized as a whole and diffracted light is not transmitted.

The opaque plate 40 may be made of the same material as the blind 31 or a metal plate or ceramic material sufficient to block the light source. However, considering the degree of strength and particle side, a steel plate is preferable.

In addition, the opaque plate 40, the x-axis polarizing plate 41, and the y-axis polarizing plate 42 may also be formed on the copper liquid surface A ′ formed between the condensing lens 32 or the lower portion of the reticle 35. Accordingly, it is possible to remove the noise due to the liquid surface separation.

When forming the opaque plate 40 has a uniformity of light, such as ⓓ without noise. Of course, the process can also be applied to steppers.

Accordingly, the noise C is removed by the opaque plate 40 and the diffracted light is removed by the polarizing plates 41 and 42 to form a trapezoidal noise B as shown in the graph ⓓ shown in FIG. 2. You can see that it is almost rectangular.

According to the noise removing device of the semiconductor exposure apparatus according to the present invention as described above, it is possible to prevent the light from being incident on the unwanted portion of the reticle to prevent the occurrence of noise in the lighting unit.

In addition, by preventing the generation of diffracted light, there is an advantage of forming a pattern of a desired shape and thereby improving the characteristics and reliability of the semiconductor device.

Claims (4)

delete delete delete In the exposure method using the exposure equipment to expose the wafer while moving the reticle and the wafer at a constant speed, And a step of projecting light through an x-axis polarizer and a y-axis polarizer in addition to the opaque plate disposed on the reticle.

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