KR20020051109A - Method for fabricating half-tone mask - Google Patents

Abstract

PURPOSE: A fabrication method of a half tone mask is provided to simplify manufacturing processes by controlling a distance between a phase shift layer and a light shield pattern according to an optical source. CONSTITUTION: A phase shift layer(22), a light shield layer and a photoresist pattern are sequentially formed on a quartz substrate(21). The phase shift layer(22) and the light shield layer are simultaneously etched by using the photoresist pattern as a mask. Then, the light shied layer is selectively etched so as to form a light shield pattern(23a). The length of the light shield pattern(23a) is relatively short compared to the phase shift layer(22). At this time, the length of the light shield pattern(23a) is controlled in accordance with an optical source, such as G-Line, H-line, i-line or deep-UV.

Description

Manufacturing method of halftone mask {METHOD FOR FABRICATING HALF-TONE MASK}

The present invention relates to a method of manufacturing a mask for photolithography of a semiconductor device, and more particularly, to a method of manufacturing a half tone mask.

In general, as the degree of integration of semiconductor devices increases, the pattern size that can be manufactured in a photolithography process is reaching its limit. In order to overcome this limitation, exposure using short wavelengths such as KrF or ArF, or enhancement of resolution and depth of focus (DOF) using a phase shift mask Is being used.

The halftone phase inversion mask is used for the contact layer among the above-described phase inversion masks (PSM), and the important factors in the halftone phase inversion mask are phase angle and transmittance, and the effect of the phase inversion mask when the transmittance is high Can be increased to improve the resolution.

Recently, a method of manufacturing a two-layer halftone mask has been proposed in which a process period is shorter than a conventional halftone phase inversion mask and the function of the halftone mask is maintained as it is.

1A to 1E are cross-sectional views illustrating a method of manufacturing a two-layer halftone mask according to the prior art.

As shown in FIG. 1A, the phase inversion layer 12, the light shielding layer 13, and the first electron beam exposure photosensitive film 14 are sequentially stacked on the quartz substrate 11, and then the first beam is formed using an electron beam. The photosensitive film 14 for electron beam exposure is patterned by exposure and development.

Subsequently, the lower light blocking layer 13 and the phase inversion layer 12 are sequentially etched using the patterned first electron beam exposure photosensitive film 14 as a mask to expose a predetermined portion of the quartz substrate 11.

As shown in FIG. 1B, the first electron beam exposure photosensitive film 14 is stripped, and then the second electron beam exposure photosensitive film 15 is applied to the entire surface.

As illustrated in FIG. 1C, the second electron beam exposure photosensitive film 15 is patterned by exposure and development using a photomask that exposes the phase inversion region. Here, reference numeral 15a denotes the patterned second electron beam exposure photosensitive film.

As illustrated in FIG. 1D, the exposed light shielding layer 13 is selectively etched to form a light shielding layer pattern 13a recessed in a predetermined ratio than the remaining second electron beam exposure photosensitive film 15a.

As shown in Fig. 1E, the remaining second electron beam exposure photosensitive film 15a is stripped to complete the two-layer halftone mask.

However, the method of manufacturing the two-layer halftone mask of the prior art described above has a problem that electron mask exposure, development, photosensitive film strip, etc. are required twice, so that the mask manufacturing period is long and the number of processes is high.

The present invention has been made to solve the problems of the prior art, and provides a method for producing a two-layer halftone mask suitable for shortening the manufacturing period of the mask used in the process, and reducing the possibility of defects caused by the complexity of the process. Its purpose is to.

1A to 1E are cross-sectional views illustrating a method of manufacturing a two-layer halftone mask according to the prior art;

2A to 2C are cross-sectional views illustrating a method of manufacturing a two-layer halftone mask according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

21: quartz substrate 22: phase inversion layer

23: light shielding layer 23a: light shielding layer pattern

24: Photosensitive film for electron beam exposure

Method of manufacturing a two-layer halftone mask of the present invention for achieving the above object is a step of sequentially forming a phase inversion layer, a light shielding layer, a photosensitive film on a quartz substrate, patterning the photosensitive film by exposure and development, the patterning Simultaneously etching the light blocking layer and the phase inversion layer by using the photosensitive film, and selectively wet etching the light blocking layer to form a light blocking layer pattern recessed from a corner of the phase inversion layer by a predetermined width. Characterized in that made.

Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. .

2A to 2C are cross-sectional views illustrating a method of manufacturing a two-layer halftone mask according to an embodiment of the present invention.

As shown in FIG. 2A, after the phase inversion layer 22, the light shielding layer 23, and the first electron beam exposure photosensitive film 24 are sequentially formed on the quartz substrate 21, a first beam is formed using an electron beam. The photosensitive film 24 for electron beam exposure is patterned by exposure and development.

Subsequently, the lower light blocking layer 23 and the phase inversion layer 22 are sequentially etched using the patterned first electron beam exposure photosensitive film 24 as a mask to form a predetermined portion of the quartz substrate 21, that is, a light transmitting region. Expose

As shown in FIG. 2B, the light shielding layer 23 under the electron beam exposure photosensitive film 24 is selectively wet-etched to form a light shielding layer pattern 23a of a shape recessed by a predetermined width L to form a phase inversion region. Only the part of the phase inversion layer 22 which affects pattern formation is exposed.

Here, L represents the distance from the edge of the light shielding layer pattern to the phase inversion layer, and L is different depending on the amount of wet etching of the light shielding layer.

At this time, the amount of etching of the light shielding layer is different depending on the type of light source, 436 nm to 872 nm when using a G-Line light source, 405 nm to 810 nm when using an H-Line light source, i-line light source In the case of using the etch process, the wafer is etched by a width of 365 nm to 730 nm and a width of 240 nm to 480 nm when the Deep-UV light source is used.

As such, selectively etching the light blocking layer by using wet etching, the distribution position of the exposure light source scattered from the edge of the mask pattern that causes deformation of the wafer image during the photo process for semiconductor manufacturing is determined. This is because the location is most severe in the range by the length and has little effect on the position farther than the two wavelengths.

As shown in Fig. 2C, the electron beam exposure photosensitive film 24 is stripped to complete a two-layer halftone mask.

As described above, in the embodiment of the present invention, after the electron beam exposure and development without exposing a separate phase inversion region, the light blocking layer and the phase inversion layer are simultaneously etched and selectively etched the light shielding layer to simplify the process. That is, only the portion of the phase inversion layer that affects the pattern formation in the phase inversion region is wet removed from the light shielding layer.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

According to the present invention as described above, by adjusting the distance between the phase inversion layer and the light shielding layer pattern on the two-layer halftone mask within a predetermined range according to the wavelength of the exposure light source, the function of the halftone mask is maintained as it is, but the mask manufacturing process is reduced. It can be effected.

Claims (2)

In the manufacturing method of the mask for exposure, Sequentially forming a phase inversion layer, a light shielding layer, and a photosensitive film on the quartz substrate; Patterning the photosensitive film by exposure and development; Simultaneously etching the light blocking layer and the phase inversion layer by using the patterned photoresist; And Selectively wet etching the light blocking layer to form a light blocking layer pattern recessed from a corner of the phase inversion layer by a predetermined width; Method for producing a two-layer halftone mask comprising a. The method of claim 1, In the forming of the recessed light shielding layer pattern, The light shielding layer pattern may be 436 nm to 872 nm using a G-Line light source, 405 nm to 810 nm using an H-Line light source, 365 nm to 730 nm using an i-line light source, and a Deep-UV light source. The case of depression of a width of 240 nm to 480 nm.