KR100930380B1 - How to fix defects in the photomask - Google Patents

Abstract

The defect correction method of the photomask of the present invention is performed in a predetermined etching process for removing defects on a photomask substrate having a material film pattern for transferring a predetermined circuit pattern and a defect formed between the material film patterns. And forming an etch stop layer exposing the defect with a material having an etch selectivity with respect to the material layer pattern, and etching the defect to remove the defect.

Photomask, defect correction, ion beam, defect, spacer

Description

Method for repairing defect of photomask

1 is a cross-sectional view illustrating a process of correcting a defect occurring in a photomask.

2 to 4b are diagrams for explaining a defect correction method of a photomask according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for correcting a defect of a photomask that can remove defects on a photomask without damaging a pattern on a photomask substrate.

The photolithography process is to uniformly apply a photoresist onto a wafer, reduce and project a pattern on a mask or a reticle using an exposure apparatus, and then develop a two-dimensional photoresist pattern through a developing process. All the steps up to the process. Since the pattern of the photomask can be referred to as the original pattern of the wafer pattern, the photomask in the semiconductor manufacturing process becomes more important as the degree of integration of devices increases. As such, a photomask used as a very important raw material in semiconductor manufacturing is a shape of a microcircuit of a semiconductor on a mask substrate. That is, the semiconductor integrated circuit is patterned by 1 to 5 times the actual size by using the light blocking film applied on the transparent mask substrate.

However, defects such as pattern size defects or residues in the photomask may occur in the photomask, and defects in the pattern in the photomask may eventually cause abnormalities in the pattern size in the photoresist to which the pattern is transferred through an exposure process. Will be raised. Management is important because the poor pattern size of the photomask directly affects the integrated circuit implemented on the wafer.

1 is a cross-sectional view illustrating a process of correcting a defect occurring in a photomask.

Referring to FIG. 1, a phase inversion film 102 is formed to invert a phase of light transmitted on a transparent substrate 100 such as quartz (Qz), and the phase inversion film 102 is integrated on the wafer to transfer onto a wafer. The light shielding film 104 which forms a circuit pattern is formed. The defect 106 is generated between the phase inversion film 102. The defect 106 may occur during the patterning process after depositing the phase shift material. Conventionally, in order to remove the defect 106, the ion beam 112 is irradiated from the ion beam generator 110 onto the defect 106, and an appropriate gas is supplied to remove the defect.

However, the substrate 100 may be damaged in the process of etching the defect site using the ion beam, and may also affect the phase inversion film 102 or the light shielding film 104, and mis-alignment. This can cause big problems. In this case, not only the pattern size of the photomask but also the phase of transmitted light may be a problem, and may cause a pattern defect.

The technical problem to be achieved by the present invention is to form a spacer-type etching prevention layer on the side of the material film pattern on the photomask to prevent damage of the material film pattern in the process of correcting and removing defects to prevent problems such as pattern defects It is to provide a photomask defect correction method.

In order to achieve the above technical problem, a method for correcting a defect of a photomask according to the present invention, on a photomask substrate having a material film pattern for transferring a predetermined circuit pattern and a defect formed between the material film pattern, Forming an etch stop layer exposing the defect with a material having an etch selectivity with respect to a material film pattern in a predetermined etching process to remove the defect; And removing the defect by etching.

The material layer pattern may include a phase inversion layer for inverting a phase of transmitted light and a light blocking layer pattern constituting the circuit pattern. In this case, the phase inversion film may be formed of molybdenum silicon nitride (MoSiN), and the light shielding pattern may be formed of chromium (Cr).

The forming of the etch stop layer may include forming an etch stop material layer having an etch selectivity with respect to the material layer pattern in a predetermined etching process for removing the defect on the photomask substrate on which the material layer pattern is formed. And etching back the etch stop layer to form a spacer-type etch stop layer exposing defects on sidewalls of the material layer pattern. At this time, the step of removing the defect may be made by a dry etching method.

delete

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below.

2 to 4b are diagrams for explaining a defect correction method of a photomask according to the present invention.

Referring to FIG. 2, in order to invert the phase of transmitted light on the mask substrate 200, for example, a phase inversion film 202 made of molybdenum silicon nitride (MoSiN) and a light shielding film pattern 204 made of chromium (Cr) may be used. It is formed by a conventional method. The light shielding pattern 204 forms an integrated circuit pattern to be transferred onto a wafer. In the process of patterning the phase shift layer 202, a defect 206 may be generated on the substrate 200.

Next, an etch stop film 208 having a predetermined thickness is formed on the resultant of the substrate on which the light shielding film pattern 204 is formed. The etch stop layer 208 is a material capable of protecting the phase shift layer 202 by having an etch selectivity with respect to the phase shift layer 202 in an etching process using an ion beam for removing the defect 206, for example. To form. The thickness of the etch stop layer 208 is preferably enough to play a role as an etch stop layer in the etching process.

Referring to FIGS. 3A and 3B, an etch-back film 208 having a spacer shape is formed on sidewalls of the phase inversion film 202 by performing etch back on the etch-stop film. The etch back process may be performed until the defect 206 is exposed, and may be performed under appropriate conditions depending on the type of the etch stop layer.

3A shows a cross section and FIG. 3B shows a plane. Referring to FIG. 3B, it can be seen that the side surface of the phase inversion film formed under the light shielding film pattern 204 surrounds the etch stop layer and the defect 206 portion is exposed.

4A and 4B, a defect is removed by performing dry etching using an etching gas on the photomask having the defect portion exposed. Since the side surface of the phase inversion film 202 is surrounded by an etching preventing film 208 in the form of a spacer, in the etching process, the phase inversion film 202 is not etched or damaged, and only a defective portion is removed. 4B is a plan view showing that the defect has been removed.

As described above, according to the method for correcting a photomask defect according to the present invention, before removing the defect generated on the photomask, the defect is formed after forming an etch barrier layer in the form of a spacer to protect the pattern formed on the substrate. Perform the removal process. Therefore, damage to the substrate or pattern due to mistakes or misalignments in the process for removing defects can be prevented.

The present invention is not limited to the above embodiments, and various modifications can be made by those skilled in the art within the technical spirit of the present invention.

Claims (6)

On the photomask substrate having a material film pattern for transferring a predetermined circuit pattern and a defect formed between the material film pattern, an etching selectivity ratio with respect to the material film pattern in a predetermined etching process for removing the defect. Forming an etch stop layer exposing the defect with a material having a; And And removing the defect by etching the defect of the photomask. The method of claim 1, wherein the material film pattern, A phase inversion film for inverting the phase of transmitted light, A method for correcting a defect of a photomask, comprising a light shielding film pattern for blocking transmitted light. The method of claim 2, The phase inversion film is formed of a molybdenum silicon nitride film (MoSiN), The light shielding pattern is formed of chromium (Cr), characterized in that the defect correction method of the photomask. delete The method of claim 1, wherein the forming of the etch stop layer comprises: Forming an etch stop material layer having an etch selectivity with respect to the material layer pattern in a predetermined etching process for removing the defect, on the photomask substrate on which the material layer pattern is formed; Etching back the etch stop material layer to form a spacer-type etch stop layer exposing a defect on a sidewall of the material layer pattern. The method of claim 1, Removing the defect is a method of correcting a defect of a photomask, characterized in that the dry etching method.

Images