KR101039139B1 - Method for fabricating phase shift mask in semicondutor device - Google Patents

Abstract

A phase inversion film is formed on the transparent substrate, and a light blocking film pattern for selectively exposing the phase inversion film is formed on the phase inversion film. After forming a buffer film pattern on the light blocking film pattern, a method of forming a phase inversion mask of a semiconductor device for forming a phase inversion film pattern by selectively etching the phase inversion film exposed by the buffer film pattern and the light blocking film pattern.

Phase inversion mask, light shielding film, oxide film, oxygen plasma

Description

Method for fabricating phase inversion mask of semiconductor device

The present invention relates to a method of forming a semiconductor device, and more particularly to a method of manufacturing a phase inversion mask of a semiconductor device.

In the process of manufacturing a semiconductor device, a photomask having a pattern is used as a method for implementing a pattern to be formed on a semiconductor substrate. Since the pattern embodied on the photomask is transferred onto the wafer through a photolithgraphy process, the manufacturing process of the photomask is very important.

In general, in order to form a phase inversion mask, first, a phase inversion film, a light blocking film, and a resist film are formed on a transparent substrate, and then a circuit pattern to be formed is transferred to the resist film using an electron beam. Subsequently, a development pattern using a developer is formed to form a resist pattern for selectively exposing the light blocking film, and then the light blocking film exposed by the resist pattern is etched to form a light blocking film pattern. Subsequently, after the resist pattern is removed, an etching process using the light blocking film pattern as an etching mask is performed to form a phase inversion film pattern. Here, the light blocking layer pattern is disposed at the edge of the subsequent phase inversion mask, for example, the frame region, to block unnecessary light.

However, in the process of forming the phase shift pattern, the thickness of the light shield layer pattern may be changed by losing the light shield layer pattern used as the etching mask. If the thickness of the light blocking layer pattern is lost and the thickness is changed, the transmittance of the light transmitted in the subsequent wafer patterning process is changed to cause a patterning defect.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method of forming a phase inversion mask of a semiconductor device capable of preventing loss of a light blocking film pattern.

In order to achieve the above technical problem, a method of forming a phase inversion mask of a semiconductor device according to the present invention, forming a phase inversion film on a transparent substrate; Forming a light blocking layer pattern selectively exposing the phase inversion layer on the phase inversion layer; Forming a buffer film pattern on the light blocking film pattern; And selectively etching the phase shift layer exposed by the buffer layer pattern and the light blocking layer pattern to form a phase shift layer pattern.

The phase inversion film pattern may be formed of a molybdenum silicon oxynitride film, and the light blocking film pattern may be formed of a chromium film.

The buffer film pattern may be formed as an oxide film pattern by performing an oxidation process using an oxygen plasma.

As described above, according to the method of forming the phase reversal mask according to the present invention, by forming a buffer film pattern on the light blocking film pattern, the light blocking film pattern is etched together in an etching process using a subsequent light blocking film pattern as an etching mask. The loss phenomenon can be prevented.

Accordingly, since the transmittance change due to the loss of the light blocking film pattern can be prevented, the disposal rate of the mask can be reduced and the manufacturing process cost can be reduced.

1 to 6 are cross-sectional views illustrating a method of forming a phase inversion mask of a semiconductor device according to the present invention.

Referring to FIG. 1, a phase inversion film 110 and a light blocking film 120 are formed on a transparent substrate 100 such as a quartz substrate. The phase inversion film 110 may be formed of a material capable of inverting the phase of transmitted light, for example, a molybdenum silicon oxynitride (MoSiON) film. The light blocking layer 120 may be formed of a material capable of blocking transmitted light, for example, a chromium (Cr) film.

Next, a resist film pattern 130 for selectively exposing the light blocking film 120 is formed on the light blocking film 120. Specifically, after the resist film is formed on the light blocking film 120, the exposure process is performed by using an ordinary electron beam (e-beem) to transfer the pattern to the resist film, and the development process using the developer is performed to perform the resist film pattern. 130 is formed.

Referring to FIG. 2, the light blocking film exposed by the resist film pattern 130 is selectively etched to form a light blocking film pattern 121 that selectively exposes the phase inversion film 130.

Referring to FIG. 3, after performing a resist strip process, a buffer layer pattern 140 is formed on an upper surface of the light blocking layer pattern 121. The buffer layer pattern 140 may be preferably formed of an oxide layer by performing an oxidation process using an oxygen plasma (O ₂ plasma).

Specifically, after loading the transparent substrate 100 having the light blocking film pattern 121 into the reaction chamber, oxygen gas is supplied into the chamber and plasma is generated by applying an appropriate voltage to form an oxide film. In this case, a natural oxide film (not shown) may be formed on the upper surface of the light blocking film pattern 121. The oxide film may be grown using oxygen plasma to more stably secure the thickness of the oxide film. The buffer layer pattern 140 serves to prevent the light blocking layer pattern 121 from being lost during an etching process using a subsequent light blocking layer pattern as an etching mask.

Meanwhile, after performing the resist strip process, the cleaning process may be performed to remove the resist residues caused during the resist strip process.

Referring to FIG. 4, an etching process using the buffer layer pattern 140 and the light blocking layer pattern 121 as an etching mask is performed to form the phase shift layer pattern 111. The etching process may be performed using plasma etching or dry etching.

Here, while the phase inversion film pattern 111 is etched, the buffer film pattern 140 may be etched to prevent the lower light blocking film pattern 121 from being lost.

Next, an annealing process is performed on the transparent substrate on which the phase shift film pattern 111 is formed. The heat treatment process may be performed at a temperature of 150 to 200 ℃. By performing the heat treatment process, the surface of the buffer film pattern 140 that is etched and damaged when the phase inversion film pattern is formed may be relaxed to prevent a change in transmittance.

On the other hand, after the phase inversion film pattern 111 is formed, the etching by-products and the like remaining on the surface of the substrate may be removed by performing a cleaning process.

Referring to FIG. 5, a second resist layer pattern 150 for selectively exposing a portion of the transparent substrate 100 on which the phase inversion layer pattern 111 and the light blocking layer pattern 121 are formed is formed. In this case, the second resist film pattern may be disposed to expose an edge region, for example, a frame portion, to block incident of subsequent unnecessary light.

Referring to FIG. 6, the light blocking film pattern 121 exposed by the second resist film pattern 150 is selectively etched to partially etch the phase shift film pattern 111 and the light blocking film in a portion of the transparent substrate 100, for example, a frame portion. The pattern 121 is formed, and only the phase inversion film pattern 111 is formed in a portion of the transparent substrate 100, for example, a main chip region inverting the phase of transmitted light.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. Do.

1 to 6 are cross-sectional views illustrating a method of manufacturing a phase inversion mask of a semiconductor device according to the present invention.

Claims (5)

Forming a phase inversion film including a molybdenum silicon oxynitride film on the transparent substrate; Forming a light blocking film pattern on the phase shifting film to selectively expose the phase shifting film, including a chromium film; Providing an oxygen plasma on the light blocking layer pattern to oxidize the surface of the chromium layer to form a buffer layer pattern of the chromium oxide layer; And And selectively etching the phase shift film exposed by the buffer layer pattern and the light blocking layer pattern to form a phase shift mask pattern. delete delete The method of claim 1, After the forming of the phase shift film pattern, The method of forming a phase inversion mask of a semiconductor device further comprising the step of performing a heat treatment process on the transparent substrate. The method of claim 1, After the forming of the phase shift film pattern, Forming a resist film pattern for selectively exposing the transparent substrate on the transparent substrate on which the phase shift film pattern and the light blocking film pattern are formed; Selectively etching the light blocking film pattern of the region exposed by the resist film pattern; And The method of claim 1, further comprising removing the resist layer pattern.

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