KR100560295B1 - Exposure apparatus for submicron pattern - Google Patents

Abstract

The present invention relates to an exposure apparatus for a fine pattern, comprising: a condenser lens for condensing an exposure source passing through an aperture, a projection lens for condensing light onto a wafer under the condenser lens, and a wafer between the condenser lens and the projection lens A mask having a fine pattern for patterning the first mirror, a first mirror disposed between the mask and the projection lens and transflecting the diffracted zero-order light passing through the mask as it is and reflecting high-order light, and the high reflected from the first mirror And a second mirror for reflecting light shielding to the projection lens. Therefore, in the present invention, by installing a first mirror between the mask and the projection lens and installing a second mirror on the mask stage, high-order light such as ± 1st, ± 3rd order, etc. reflected through the first and second mirrors is converted into the projection lens. By condensing and irradiating a wafer, the fine pattern of a mask can be projected as it is to the resist of a wafer.

Exposure device, projection lens, high light shielding, diffraction

Description

Exposure device for fine pattern {EXPOSURE APPARATUS FOR SUBMICRON PATTERN}             

1 is a view showing an illumination system of a general exposure apparatus,

2 shows an exposure apparatus for a fine pattern according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: aperture

102: condenser lens

104: mask

106: first mirror

108: second mirror

110: projection lens

112: wafer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and in particular, to an exposure apparatus for fine patterns for focusing high light shielding having information on a mask pattern onto a projection lens.

Photolithography technology for forming finer patterns has been researched and developed according to the trend of higher integration and higher density of semiconductor devices. In addition, high resolution and depth of focus (DOF) are required to remove ultra-high density devices, and thus, deformed illumination methods such as an off-axis method using apertures are actively utilized. ought.

Most commonly used aperture lighting systems include annular, quadruple, and dipole, and cross-pole exposure technology has also been studied. It is becoming.

1 is a view showing an illumination system of a general exposure apparatus.

As shown in FIG. 1, the illumination system of the exposure apparatus includes an aperture 10, which is a light limiting means for controlling a laser light as an exposure source, and a condenser lens for condensing an exposure source passing through the aperture 10. A projection lens 16 for condensing light onto the wafer 18 under the condenser lens 12, and a pattern for patterning the wafer 18 between the condenser lens 12 and the projection lens 16. A mask 14, which is a reticle, is provided.

In the conventional illumination system configured as described above, a resist is applied through the projection lens 16 after the laser light, which is an exposure source, is filtered through the aperture 10 and the condenser lens 12, is collected and passed through the mask 14. The wafer 18 is irradiated. As a result, the pattern formed on the mask 14 is projected onto the wafer 18 as it is.

When such exposure is performed, the laser light passing through the condenser lens 12 and the mask 14 is diffracted by the diffraction component into 0th order and high order light (for example, ± 1st order, ± 3rd order, etc.). In the diffracted light, the 0th order light indicates the intensity of light, and the remaining high order light (± 1st order, ± 3rd order, etc.) has information of a mask pattern. Such high light shielding must be focused on the projection lens to implement the desired mask pattern in the resist of the wafer.

As a method for condensing the diffracted high light beam onto the projection lens, a method of condensing the high light beam onto the projection lens by narrowing the distance between the projection lens and the mask, and modifying the illumination system, that is, injecting laser light into the mask axis) to focus high-shielding light on the projection lens.

However, this conventional technology has a lot of difficulties in the manufacturing process due to limitations in modifying the illumination system of the exposure apparatus in hardware.

An object of the present invention is to ± 1 order reflected through the first and second mirror by providing a first mirror between the mask and the projection lens and a second mirror on the mask stage to solve the problems of the prior art as described above The present invention provides an exposure apparatus for a micropattern that can project a fine pattern of a mask as it is onto a resist of a wafer by condensing high-shielding light such as ± 3rd order with a projection lens and irradiating the wafer.

In order to achieve the above object, the present invention provides an exposure apparatus, comprising: a condenser lens for condensing an exposure source passing through an aperture, a projection lens for condensing light onto a wafer under the condenser lens, and a condenser lens and a projection lens. A mask having a fine pattern for patterning the wafer, a first mirror disposed between the mask and the projection lens and transflecting the diffracted zero-order light passing through the mask as it is and reflecting high-order light, and reflected from the first mirror And a second mirror for reflecting high light shielding to the projection lens.

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

2 is a view showing an exposure apparatus for a fine pattern according to the present invention.

As shown in FIG. 2, the illumination system of the exposure apparatus according to the present invention includes a condenser lens for condensing an aperture 100, which is a light limiting means for controlling a laser beam as an exposure source, and an exposure source that has passed through the aperture 100. 102, a projection lens 110 for condensing light onto the wafer 112 under the condenser lens 102, and a pattern for patterning the wafer 112 between the condenser lens 102 and the projection lens 110. A first mirror 106 disposed between the mask 104 which is a reticle, the mask 104 and the projection lens 110, which transmits zero-order light as it is, transmits a portion of the high-order light as it is, or reflects the high-order light; A second mirror 108 is provided on the mask 104 stage and reflects the high-shielding light reflected from the first mirror 106 to the projection lens 110.

The first mirror 106 is installed in the center of the optical path between the mask 104 and the projection lens 110 and has a parabolic shape having a curvature of the mirror surface toward the projection lens 110 inward. . The first mirror 106 semi-transmits the zero-order light as it is, and a semi-transmissive layer is provided at the center of the mirror to make the speed or phase difference of the transmitted zero-order light equal to the high-order light reflected from the second mirror 108. do. In this case, a phase shifter may be installed instead of the transflective layer. In addition, the first mirror 106 reflects the high-order light, such as diffracted ± 1st order, ± 3rd order, and the like, which has passed through the mask 104 and enters the second mirror 108.

On the other hand, the high order light of the diffracted ± 1st order, ± 3rd order, etc. that passed through the mask 104 may be transmitted as it is without being reflected by the first mirror 106 and may be immediately focused on the projection lens 110.

The second mirror 108 is provided in pairs on both sides of the mask 104 stage, and has a parabolic shape with the curvature of the mirror surface facing the projection lens 110 inwards like the first mirror 106. The second mirror 108 reflects the high-order light such as ± 1 order, ± 3 order, and the like reflected from the first mirror 106 to condense the projection lens 110.

In the illumination system of the exposure apparatus according to the present invention configured as described above, when the laser light as the exposure source is focused through the aperture 100 and the condenser lens 102 and incident through the pattern of the mask 104, the mask 104 and the projection lens are provided. Of the laser light passing through the mask 104 through the first mirror 106 provided between the 110, the 0th order light is transflected as it is and is focused on the projection lens 110.

Part of the high-order light, such as ± 1st, ± 3rd, etc., diffracted among the laser beams passing through the mask 104 is also semi-transmitted through the first mirror 106 as it is and is focused on the projection lens 110. At the same time, the remaining high-order light diffracted in the laser light is reflected through the first mirror 106 and incident on the second mirror 108.

The second mirror 108 provided on both sides of the mask 104 stage reflects high-order light such as ± 1 order, ± 3 order, and the like reflected from the first mirror 106 to condense the projection lens 110.

Then, high order light, such as 0th order light, ± 1st order, ± 3rd order, and the like, which is focused on the projection lens 110, is irradiated onto the wafer 112 on which the resist is applied, and thus the fine pattern formed on the mask 104 is exposed to the wafer ( Projected onto the resist of 112). At this time, since the zero-order light focused on the projection lens 110 is changed in phase by the transflective layer or the phase shifter of the first mirror 106, the first order, ± 3rd order, etc., focused on the projection lens 110 are high. It becomes the same as the light shielding phase.

Moreover, since the first and second mirrors 106 and 108 used in the present invention take a parabolic shape with respect to the projection 110, the amount of high light shielding focused by the projection lens 110 can be further increased.

On the other hand, the present invention is not limited to the above-described embodiment, various modifications are possible by those skilled in the art within the spirit and scope of the present invention described in the claims to be described later.

As described above, the present invention does not require the use of an incidence illumination system used for condensing high-order light, such as ± 1st order, ± 3rd order, etc., which is diffracted in a conventional mask. Through the two mirrors, the high light shielding may be focused on the projection lens to project the fine pattern of the mask on the wafer as it is. In other words, the present invention provides a projection lens to reflect high order light such as ± 1st order, ± 3rd order, etc. reflected through the first and second mirrors by providing a first mirror between the mask and the projection lens and installing a second mirror on the mask stage. By condensing and irradiating the wafer, fine pattern information of the mask can be projected onto the resist of the wafer as it is by the diffracted high shielding light passing through the mask.

Furthermore, the exposure apparatus of the present invention can be applied to both a stepper, a scanner, and the like, and can be installed regardless of the number of numerical apertures (NA) of the projection lens.

Claims (6)

In the exposure apparatus, A condenser lens for condensing an exposure source passing through the aperture; A projection lens for condensing light onto a wafer under the condenser lens; A mask having a fine pattern for patterning a wafer between the condenser lens and the projection lens; A first mirror disposed between the mask and the projection lens and transflecting the diffracted zero-order light passing through the mask as it is and reflecting high-order light; And And a second mirror for reflecting the high shielding light reflected from the first mirror to the projection lens. The method of claim 1, The first mirror is an exposure apparatus for a fine pattern, characterized in that the mirror surface toward the projection lens is made of a parabolic form having a curvature inwardly. The method of claim 1, And the first mirror is disposed at the center of the optical path between the mask and the projection lens. The method of claim 1, And the first mirror comprises a transflective layer or a phase shifter in the center thereof. The method of claim 1, The second mirror is an exposure apparatus for a fine pattern, characterized in that the mirror surface toward the projection lens is made of a parabolic shape having a curvature inwardly. The method according to claim 1 or 5, The second mirror is an exposure apparatus for a fine pattern, characterized in that provided in pairs on both sides of the stage of the mask.

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