KR20040059451A - Photo lithography apparatus - Google Patents

Abstract

PURPOSE: A photolithography apparatus is provided to prevent the destructive interference of light by deflecting light using an aperture module with a vertical polarization filter and a horizontal polarization filter. CONSTITUTION: A photolithography apparatus includes an aperture module(10) and an optical module. The aperture module includes a plurality of apertures(12,14,16,18). A vertical polarization filter is attached to the two apertures. A horizontal polarization filter is attached to the other apertures. The optical module is used for printing a pattern of a predetermined mask on a wafer by using vertically polarized light and horizontally polarized light of the aperture module.

Description

Photo lithography apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photolithography apparatus, and more particularly to deflecting light due to interference by deflecting light passing through each aperture.

The photolithography process transfers a pattern of a mask or stepper onto a wafer and has a structure in which light generated from a light source is finally focused on the wafer through various devices.

Specifically, the light of the light source proceeds to the reflector through the aperture, and the light reflected from the reflector proceeds to the mask. The pattern of the mask is thus transferred onto the wafer after passing through the lens.

Then, the photoresist on the wafer is exposed according to the transferred and focused shape, and when the exposed photoresist is developed and cleaned, an area to be etched and an area to be masked can be distinguished, and an unmasked area is etched in a subsequent etching process. do.

In the bar described above, four apertures are configured in the case of Quadropole modified illumination, and each aperture is poled.

However, in the conventional photolithography apparatus as described above, since light passing through each aperture has a coherent characteristic, specific frequencies among the components diffracted after passing through the mask overlap, whereby Since interference occurs, contrast is reduced.

The lowering of the contrast eventually causes a decrease in resolution, resulting in a poor exposure state of the wafer.

An object of the present invention is to polarize light passing through different apertures in different directions to prevent interference between components overlapping frequencies among components diffracted by the pattern of the mask.

1 shows an embodiment of a photolithography apparatus according to the present invention.

The photolithography apparatus according to the present invention includes an aperture module having a plurality of apertures, each aperture of which is separately attached to a vertical polarization filter and a horizontal polarization filter, and a horizontal polarization and a horizontal polarization transmitted from the aperture module. An optical module for transferring a pattern formed on a predetermined mask to a wafer using directional polarization.

Here, the aperture module has four apertures for quadropole modified illumination, and is divided into pairs to attach the vertical polarization filter and the horizontal polarization filter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a photolithographic apparatus according to the present invention will be described below with reference to the accompanying drawings.

The photolithography apparatus according to the present invention is composed of an aperture module 10 and an optical module for transmitting light as shown in FIG. 1, and the optical module includes a reflector 20 and a lens 22. The mask 22 is disposed between the reflector 20 and the lens 24, and the wafer 26 is disposed below the lens 24.

Specifically, the aperture module 10 is configured to transmit light provided from a light source (not shown), and the aperture module 10 includes apertures 12 corresponding to four poles for quadropole modified illumination. 14, 16, 18).

In addition, each aperture 12, 14, 16, 18 is attached to a polarizing filter (not shown), of which two upper apertures 12, 14 in a pair of a vertical polarizing filter is attached, The lower two apertures 16, 18 may be paired to attach a horizontal polarization filter. Alternatively, the two apertures 12, 16 on the left side of each aperture 12, 14, 16, 18 form a pair, and a vertical polarization filter is attached, and the two apertures 14, 18 on the right side are attached. In a pair, the horizontal polarizing filter may be attached. In the above two examples, the positions of the vertical polarization filter and the horizontal polarization filter may be modified.

Then, a reflector 20 reflecting the progress of the vertically polarized light A and the horizontally polarized light B transmitted from the aperture module 10 is configured, and a mask 22 is formed under the reflector 20, and the mask 22 The lens 24 is formed under the lens 24, and the wafer 26 is disposed under the lens 24.

Here, the mask 22 is a pattern in which wiring lines to be exposed on the wafer 26 are patterned by a chrome pattern, and the lens 24 is schematically illustrated, but the pattern size of the mask 22 is reduced and transferred to the wafer 26. It is. The wafer 26 is coated with a photoresist for exposure.

According to the above configuration, the horizontally polarized light A and the vertically polarized light B transmitted through the aperture module 10 are reflected by the reflector 20, and the reflected light passes through the mask 22.

At this time, the pattern of the mask 22 is fine and causes diffraction of light, and the diffracted light has components distributed and distributed for each frequency. The diffraction component for the vertically polarized light A is referred to as A1, and the diffraction component for the horizontally polarized light B is referred to as B1.

In this case, the diffraction component A1 and the diffraction component B1 may be frequency-overlaid.

If the light has the same phase and polarization direction, interference occurs. However, according to the present invention, as the diffraction component A1 and the diffraction component B1 differ in polarization directions, mutual interference is not caused.

Therefore, the pattern of the mask can be transferred through the lens 24 onto the wafer 26 without damaging the interference of light while maintaining a certain level or more of resolution.

Accordingly, the photolithography process can be performed at a resolution of a certain level or more even for a fine pattern without reducing contrast due to mutual interference of light.

Meanwhile, the polarization filter attached to each aperture 12 of the aperture module 10 may be selectively installed before or after the light is transmitted.

According to the present invention, since the loss due to the overlapping of the diffracted components due to the fine pattern is prevented, it is possible to secure the contrast and the resolution in a good state, thereby improving the wafer exposure capability.

Claims (4)

An aperture module in which a plurality of apertures are formed and each aperture is separately attached to a vertical polarization filter and a horizontal polarization filter; And And an optical module for transferring a pattern formed on a predetermined mask onto a wafer using vertical polarization and horizontal polarization transmitted from the aperture module. The method of claim 1, The aperture module has four apertures for quadropole modified illumination and is divided into pairs to attach the vertical polarization filter and the horizontal polarization filter. The method of claim 2, And the four apertures are set such that two at the top and two at the bottom are paired, respectively. The method of claim 2, And the four apertures are configured such that two on the left and two on the right are paired, respectively.