KR20090064642A - Reticle structure for patterning active layer with fine patterns - Google Patents

Abstract

A reticle structure for patterning an active region of a minute pattern is provided to stabilize a photo process and an etching process by forming a reticle of a new structure. A reticle structure for patterning an active region of a minute pattern includes a first pattern(100), a second pattern(200), and a third pattern(300). The first pattern defines the active region. The first pattern is formed by laminating quartz and a phase shift layer. The second pattern defines a field region. The second pattern is made of quartz. The third pattern defines the active region. The third pattern is separated from a concave part of the first pattern. Width of the third pattern is 30~40nm. The third pattern is made of quartz.

Description

Reticle structure for patterning active layer with fine patterns}

The present invention relates to a reticle structure for patterning an active region of a fine pattern, and more particularly, to an active region patterning of a fine pattern to compensate for an optical proximity effect to secure an overlay margin between the active region and the gate electrode layer. Relates to a reticle structure.

In general, a photolithography process of manufacturing a semiconductor device uses various exposure apparatuses for patterning a predetermined pattern formed on a reticle on a semiconductor substrate.

As the semiconductor device is highly integrated, a fine pattern is reduced through a reduction projection optical system, and a step and repeat method having relatively high throughput and excellent overlay accuracy is applied to a plurality of shot regions on a substrate coated with a photoresist film. Step & repeat type stepper or step & scan type scanner is mainly used.

The resolution of the projection optical system constituting such a reduced projection exposure apparatus is expressed by a relationship of R = k ₁ x lambda / NA, as is well known by the Rayleigh equation. In addition, the depth of focus (hereinafter, referred to as 'DOF') of the projection optical system is expressed in a relationship of DOF = k ₂ · λ / (NA) ² .

Where R is the resolving power of the projection optical system, λ is the wavelength of the light source, NA is the numerical aperture of the projection optical system, k _{1 ,} or k ₂ is determined by the resolution of the photosensitive film or other process conditions. Is a constant.

Therefore, as shown in the Rayleigh equation, in order to realize a fine pattern, a method of making a large amount of primary light to be projected by the lens by reducing the diffraction angle diffracted by the mask using a short wavelength or including a large amount of primary light information can be included. There is a way to increase the aperture of the lens, or NA.

Currently, the method of increasing the NA is continuously studied, but increasing the size of the lens is limited due to various issues such as aberration of the lens itself. Margins are reduced, so proper lens size is required. Therefore, the current process technology is being developed to implement a fine pattern using a short wavelength.

As a way to reduce development and production costs in semiconductor manufacturing, instead of using expensive new model exposure equipment with excellent resolution and performance, the existing exposure equipment is used to form a small pattern compared to the limitation of the exposure equipment itself. Attempts are being made.

One such attempt is to improve resolution by exposing with a phase shift mask.

1A to 1H are cross-sectional views illustrating a conventional process of manufacturing a phase inversion mask.

Referring to FIGS. 1A to 1B, an E-beam lighter E is applied after applying a resist for electron beams to a disc of a reticle in which a quartz substrate, a phase inversion layer, and a chromium layer are sequentially stacked. The beam is then examined by a beam writer and developed.

1C to 1D, after etching the chromium layer and the phase inversion layer by performing a dry etching process, the resist for the electron beam is removed.

Referring to FIGS. 1E to 1F, after applying the electron beam resist again, the electron beam is irradiated by an E-beam writer and then developed.

Referring to FIGS. 1G to 1H, after etching the chromium layer which is not masked to the electron beam resist by wet etching, the conventional phase inversion mask fabrication process is completed by removing the electron beam resist. .

Generally, to form a desired pattern in a photolithography process for semiconductor manufacturing, a reticle is required together with an exposure apparatus and a photoresist film. A reticle is an original plate used to project a repetitive semiconductor circuit pattern onto a silicon wafer. The reticle is made of a quartz plate having a chromium pattern of 4 or 5 times the size of the reduction projection.

Such patterns on the reticle should have the same critical dimension (hereinafter referred to as 'CD') for the same layout pattern. That is, fidelity of the pattern becomes an important factor in the reticle production. In recent years, as the line width of semiconductor devices decreases, the demand for such fidelity increases.

On the other hand, while the wavelength of the light source used in the exposure equipment approaches the minimum feature size of the semiconductor device, pattern distortion occurs due to diffraction, interference, or the like of light. In other words, the optical system that projects the image on the reticle onto the wafer acts as a low-pass filter when expressed as a Fourier transformation.

Therefore, since the edge portion of the pattern, which is a high frequency portion, does not transmit, an image formed on the wafer is different from the original shape. In addition, distortion occurs due to the influence of adjacent patterns, which is called an optical proximity effect.

In order to overcome the distortion of the pattern caused by the optical proximity effect, a method of deliberately changing the reticle pattern, that is, attaching a serif to the edge of the pattern, has been attempted. It is called 'OPC'.)

Figure 2a is a layout showing the pattern of the active area on the initial layout, Figure 2b is a layout showing the pattern of the active area to which the OPC is applied to Figure 2a, Figure 2c is expected by the reticle produced by the pattern of Figure 2b FIG. 3 is a layout diagram showing a photoresist pattern on a wafer, FIG. 3 is a layout diagram showing a pattern of a gate electrode on an initial layout, and FIG. 4 is a layout diagram showing that the patterns of FIGS. 2A to 2C and 3 overlap. 5 is an electron micrograph showing the pattern of the active region and the gate electrode on the actual wafer by the reticle produced by the pattern of FIG. 2b.

As shown in FIGS. 2A to 2B, the pattern of the active area on the original layout (original DB) and the image on the expected wafer after applying the OPC (FIG. 2C) are larger than the pattern of the active area on the original layout. do. As a result, as illustrated in FIG. 4, the overlay margin between the active region and the gate electrode is insufficient.

In fact, as shown in the accompanying FIG. 5, it can be seen that the pattern overlay margin of the active region and the gate electrode on the wafer is insufficient.

Accordingly, an object of the present invention is to provide a reticle structure for patterning an active region of a fine pattern that can compensate for an optical proximity effect and secure an overlay margin between an active region and a gate electrode layer. There is this.

The reticle structure for patterning the active region of the fine pattern of the present invention for realizing the object as described above is a pattern defining the active region as a first pattern formed by laminating quartz and a phase inversion layer, and a pattern defining the field region. And a third pattern made of quartz and a pattern defining an active region, the third pattern being spaced apart from the concave portion of the first pattern.

The phase inversion layer of the first pattern may be formed of a MoSi layer.

In addition, the width of the third pattern is characterized in that formed in 30 ~ 40nm.

In addition, the third pattern is characterized in that made of quartz.

In addition, the third pattern is characterized in that the quartz, phase inversion layer, chromium layer is laminated.

As described in detail above, according to the reticle structure for patterning the active region of the fine pattern according to the present invention, a reticle having a new structure ensures an overlay margin between the active region and the gate electrode layer, thereby stabilizing the photo process and the etching process. In addition to improving the transistor characteristics, there is an effect that can improve the transistor characteristics.

The reticle structure for patterning an active region of a fine pattern according to an embodiment of the present invention includes first to third patterns.

The first pattern is a pattern on a reticle formed by stacking quartz and a phase inversion layer as a pattern defining an active region, and the second pattern is a pattern on a reticle made of quartz as a pattern defining a field region, and the third pattern Is a pattern defining an active region and is a pattern on a reticle formed spaced apart from the concave portion of the first pattern.

In the reticle structure for patterning the active region of the fine pattern according to another embodiment of the present invention, the phase inversion layer of the first pattern is preferably formed of a MoSi layer.

In the reticle structure for patterning the active region of the fine pattern according to another embodiment of the present invention, it is preferable that the width of the third pattern is 30 to 40 nm.

In the reticle structure for patterning the active region of the fine pattern according to another embodiment of the present invention, the third pattern is preferably made of quartz.

In a reticle structure for patterning an active region of a fine pattern according to another embodiment of the present invention, the third pattern is preferably formed by laminating a quartz, a phase inversion layer, and a chromium layer.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

6A is a front view illustrating a reticle structure for patterning an active region of a fine pattern according to an embodiment of the present invention. FIG. 6B is a cross-sectional view taken along line AA ′ of FIG. 6A, and FIG. 7A is a front view illustrating a reticle structure for patterning active regions of a fine pattern according to another exemplary embodiment of the present invention. FIG. 7B is a cross-sectional view taken along line AA ′ of FIG. 7A.

As shown in FIGS. 6A to 6B, the reticle structure for patterning the active region of the fine pattern according to the exemplary embodiment of the present invention may include the first pattern 100, the second pattern 200, and the third pattern ( 100).

The first pattern 100 is a pattern on the reticle formed by stacking quartz and a phase inversion layer as a pattern defining an active region. The phase inversion layer is preferably formed of a MoSi layer.

The second pattern 200 is a pattern defining a field region and is a pattern on a reticle made of quartz.

The third pattern 300 is a pattern defining an active region, and is a pattern on a reticle formed to be spaced apart from the concave portion of the first pattern 100. In this case, the width of the third pattern 300 is preferably formed to 30 to 40 nm.

Here, the third pattern 300 is preferably made of quartz. Accordingly, as shown in FIGS. 6A to 6B, by removing the Mosi layer in the center of the first pattern 100, the distortion of the pattern due to the optical proximity effect may be reduced by the destructive interference caused by the phase inversion. .

As shown in FIG. 7A to FIG. 7B, the third pattern 300 of the reticle structure for patterning the active region of the fine pattern according to another embodiment of the present invention may be formed of quartz, phase inversion layer, and chromium (Cr). ) Layer is preferably laminated.

Therefore, this is a method of preventing phase interference by eliminating phase reversal and blocking light with the chromium layer to prevent light from being transmitted, thereby reducing the distortion of the pattern due to the optical proximity effect.

It will be apparent to those skilled in the art that the present invention is not limited to the above embodiments and can be practiced in various ways without departing from the technical spirit of the present invention. will be.

1A to 1H are cross-sectional views illustrating a conventional process of manufacturing a phase reversal mask;

2A is a layout diagram showing a pattern of an active region on an initial layout;

FIG. 2B is a layout diagram illustrating a pattern of an active region to which an OPC is applied to FIG. 2A;

FIG. 2C is a layout showing a photoresist pattern on a wafer expected by a reticle produced by the pattern of FIG. 2B;

3 is a layout showing patterns of gate electrodes on an initial layout;

4 is a layout showing that the patterns of FIGS. 2A to 2C and 3 overlap;

FIG. 5 is an electron micrograph showing a pattern of an active region and a gate electrode on an actual wafer by a reticle manufactured by the pattern of FIG. 2B;

6A is a front view showing a reticle structure for patterning an active region of a fine pattern according to an embodiment of the present invention;

6B is a cross-sectional view taken along the line AA ′ of FIG. 6A;

7A is a front view showing a reticle structure for patterning active regions of a fine pattern according to another embodiment of the present invention;

FIG. 7B is a cross-sectional view taken along the line AA ′ of FIG. 7A; FIG.

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

100: first pattern 200: second pattern

300: third pattern

Claims (5)

A first pattern in which quartz and a phase inversion layer are laminated as a pattern defining an active region, a second pattern made of quartz as a pattern defining a field region, and a pattern defining an active region, spaced apart from the concave portion of the first pattern Reticle structure for patterning the active region of the fine pattern comprising a third pattern formed by. The reticle structure of claim 1, wherein the phase inversion layer of the first pattern is formed of a MoSi layer. The reticle structure of claim 1, wherein the third pattern has a width of about 30 nm to about 40 nm. The reticle structure of claim 1, wherein the third pattern is made of quartz. The reticle structure of claim 1, wherein the third pattern is formed by stacking a quartz, a phase inversion layer, and a chromium layer.

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