KR101153998B1 - Method for repairing pattern bridge defects of photo mask - Google Patents

Abstract

A method of correcting a pattern bridge defect of a photo mask is provided. According to the present invention, the phase inversion layer and the light shielding layer are first etched on the photomask substrate by using the original resist pattern to form the light shielding layer pattern and the phase inversion layer pattern, and cause a pattern bridge defect. Clean the particles. By primary etching, a portion of the photomask substrate exposed by the original resist pattern is filled and a modified resist pattern is formed to expose the portion of the original resist pattern. The photoresist substrate portion is protected by a modified resist pattern, and the defect is removed by second etching the original resist pattern with the etching mask on the light blocking layer portion and the lower phase inversion layer portion exposed by the original resist pattern at the pattern bridge defect portion.

Pattern Bridge, Particles, Negative Photoresist

Description

Method for repairing pattern bridge defects of photo mask

1 to 4 are cross-sectional views schematically illustrating a method for correcting a pattern bridge defect of a photo mask according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor devices, and more particularly, to a method of correcting a pattern bridge defect of a photo mask.

In the process of manufacturing a semiconductor device, a photolithography process for transferring a pattern to be implemented on a wafer is mainly used. In order to precisely transfer a pattern onto a wafer in such a photolithography process, a process of forming a pattern to be transferred onto a wafer on a photomask is mainly recognized.

Among the photo masks, an attenuated PSM is a region consisting of a phase inversion layer (main pattern region) on a transparent quartz substrate that transmits light and a light shielding layer region that does not transmit light at all. It consists of. However, if the particles fall into the area to be patterned after development for resist pattern formation during the mask manufacturing process, the etching is not normally performed on this part in a subsequent dry etch process. Pattern bridge defects occur.

When such a pattern bridge defect occurs, conventionally, after removing the light shielding layer of the chromium (Cr) layer, the phase inversion layer is corrected by using gallium (Ga) ions in a focus ion beam (FIB) correction apparatus. When this method is used, stains due to residual Ga ions remain on the surface of the quartz substrate, and such stains are a factor of lowering the transmittance of the quartz substrate. In addition, it is difficult to implement the correction pattern in the same pattern as the normal region due to an image shift due to charge up during correction. In addition, a problem arises in that the phase inversion layer pattern profile of the modified region is not the same as the normal region.

The pattern defect of the modified portion and the phase reversal layer pattern profile change due to the decrease in transmittance and the image shift of the quartz substrate result in the defect of the pattern line width (CD) in the correction region during wafer exposure. Accordingly, there is a need for development of a method that can solve problems that may arise from such FIB modification.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method for correcting pattern bridge defects in a photomask, which may solve problems associated with FIB correction.

One aspect of the present invention for achieving the above technical problem, forming a phase inversion layer and a light shielding layer on a photo mask substrate, forming an original resist pattern for patterning on the light shielding layer, the original resist pattern Selectively etching the light shielding layer and the phase inversion layer using an etch mask to form a light shielding layer pattern and a phase inversion layer pattern, and particles generating a pattern bridge defect during the selective primary etching. Cleaning the photomask substrate to remove a), filling the photomask substrate portion exposed by the original resist pattern by the primary etching and forming a modified resist pattern that exposes the original resist pattern portion; Protecting the photomask substrate portion with the modified resist pattern and Second etching the original resist pattern with an etch mask on the portion of the light shielding layer and the lower portion of the phase inversion layer exposed by the original resist pattern at the ridge defect portion, and the correction resist pattern and the original resist pattern A method of correcting a pattern bridge defect of a photo mask, comprising selectively removing the same, is provided.

The light shielding layer may include a chromium layer.

The forming of the modified resist pattern may include applying a modified resist layer covering the original resist pattern, and exposing an exposure light source selectively shielded by the light blocking layer pattern and the pattern bridge portion to a rear surface of the photomask substrate. Incident to expose the quartz crystal layer, and developing the exposed quartz crystal layer.

The quartz resist layer may be formed by applying a negative photoresist material.

Exposing the quartz resist layer may be performed in a stepper or scanner exposure apparatus.

Before applying the modified resist layer, hardening the original resist pattern, for example, performing a helium plasma treatment on the surface of the original resist pattern.

The second etching may include dry etching the exposed pattern bridge portion.

The method may further include selectively removing the light blocking layer pattern after removing the original resist pattern and the modified resist pattern.

According to the present invention, it is possible to provide a method for correcting pattern bridge defects in a photo mask that can solve the problems associated with FIB correction.

Hereinafter, 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. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and the like of the elements in the drawings are exaggerated to emphasize a more clear description, and the elements denoted by the same reference numerals in the drawings means the same elements.

In an embodiment of the present invention, a method for modifying a chromium pattern bridge caused by a foreign substance generated in a photomask manufacturing process before a dry etching step after development in the same manner as a normal pattern is provided.

After applying the dry etching, a negative photoresist layer (negative PR (photo resist)) is preferably coated on the pattern surface before the resist strip, leaving only the exposed portions. From the backside of the mask, the entire mask is exposed using an exposure apparatus (e.g., a stepper or scanner).

At this time, in order to prevent damage caused by coating on the original resist pattern of the bridge generation region before applying the negative PR, helium plasma treatment is performed on the dry etching equipment, thereby preventing the original resist pattern. Hardening.

Applying the resist for correction and post-exposure development, filling the exposed portion of the quartz substrate with the correction resist, removing the other applied correction resist, and using the original resist pattern of the bridged area as a mask, The pattern bridge is etched by dry etching. Afterwards, by etching the lower phase inversion layer by a dry etching process, it is possible to prevent the occurrence of problems such as poor transmittance and pattern defects of the quartz substrate which can be generated from the conventional FIB modification.

1 to 4 are cross-sectional views schematically illustrating a method for correcting a pattern bridge defect of a photo mask according to an embodiment of the present invention.

Referring to FIG. 1, preferably, for example, a molybdenum-silicon (Mo-Si) phase inversion layer and a chromium (Cr) light shielding layer are formed on a photo mask substrate 100 of a quartz substrate, and patterning is performed on the light shielding layer. The original resist pattern 410 is formed. The light blocking layer pattern and the phase inversion layer pattern 201 are sequentially formed by sequentially dry etching the light blocking layer and the phase inversion layer using the original resist pattern 410 as an etching mask.

In this case, the unpatterned light shielding layer portion 300 and the phase inversion layer portion 200 may be caused by the pattern bridge defect during selective primary etching due to the adsorption of foreign matter such as particles 500. Thereafter, in order to remove the particle 500 causing such a defect, the photo mask substrate 100 is cleaned using pure water or the like.

Referring to FIG. 2, a modified resist layer 450 covering the original resist pattern 410 is preferably formed by applying a negative photoresist material. Subsequently, an exposure light source selectively shielded by the light blocking layer pattern 301 and the pattern bridge portion is incident on the rear surface of the photo mask substrate 100 to expose the modified resist layer 450. In this case, the exposure may be performed in a stepper or scanner exposure apparatus.

Meanwhile, before applying the modified resist layer 450, a hardening process may be further performed to protect the original resist pattern 410. For example, the surface of the original resist pattern 410 is cured by helium plasma treatment.

Thereafter, the exposed quartz crystal layer 450 is developed. Accordingly, as shown in FIG. 3, the modified resist pattern filling the portion of the photomask substrate 100 exposed by the original resist pattern 410 by primary etching and exposing the portion of the original resist pattern 410 ( 451 is formed.

Afterwards, the portion of the photomask substrate 100 is protected by the modified resist pattern 451 and the light blocking layer portion 300 and the lower phase inversion layer portion 200 exposed by the original resist pattern 410 at the pattern bridge defect portion. 2) dry etching the original resist pattern 410 with an etching mask. Such dry etching may be performed sequentially. Accordingly, the pattern bridge defect is removed to pattern the crystal light shielding layer pattern 303 and the crystal phase inversion layer pattern 203.

Thereafter, the modified resist pattern 451 and the original resist pattern 410 are selectively removed. If necessary, the light blocking layer patterns 301 and 303 may be selectively removed for the attenuated PSM configuration.

According to the present invention described above, the Cr pattern bridge defect can be corrected to the same state as the normal region without lowering the transmittance, pattern defect and pattern profile change of the quartz substrate. As a result, it is possible to suppress the occurrence of line width defects in the correction region during wafer exposure. Accordingly, the quality of the mask can be improved, and the cost of mask remanufacturing due to the defective wafer exposure can be reduced.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to this, It is clear that the deformation | transformation and improvement are possible by the person of ordinary skill in the art within the technical idea of this invention.

Claims (9)

Forming a phase inversion layer and a light shielding layer on the photo mask substrate; Forming an original resist pattern for patterning on the light shielding layer; Selectively etching the light blocking layer and the phase inversion layer using the original resist pattern as an etching mask to form a light blocking layer pattern and a phase inversion layer pattern; Cleaning the photomask substrate to remove particles that caused pattern bridge defects during the selective primary etching; Forming a modification resist pattern filling the portion of the photomask substrate exposed by the original resist pattern by the primary etching and exposing the portion of the original resist pattern; The photoresist substrate portion is protected by the modified resist pattern, and the light blocking layer portion and the lower phase inversion layer portion exposed by the original resist pattern at the pattern bridge defect portion are secondary to the original resist pattern as an etch mask. Etching; And Selectively removing the modified resist pattern and the original resist pattern, Forming the modified resist pattern is Applying a quartz resist layer overlying said original resist pattern; Performing, in a stepper or scanner exposure apparatus, the step of injecting an exposure light source selectively shielded by the light shielding layer pattern and the pattern bridge portion to a rear surface of the photo mask substrate to expose the quartz resist layer; And And developing the exposed corrected resist layer. Claim 2 has been abandoned due to the setting registration fee. The method of claim 1, delete Claim 4 was abandoned when the registration fee was paid. The method of claim 1, And the correction resist layer is formed by applying a negative photoresist material. delete Claim 6 was abandoned when the registration fee was paid. The method of claim 1, Prior to applying the quartz resist layer And hardening the original resist pattern. Claim 7 was abandoned upon payment of a set-up fee. The method of claim 6, The curing step And helium plasma treatment of the surface of the original resist pattern. Claim 8 was abandoned when the registration fee was paid. The method of claim 1, And etching the dry patterned portion of the exposed pattern bridge portion. Claim 9 was abandoned upon payment of a set-up fee. The method of claim 1, And selectively removing the light shielding layer pattern after removing the original resist pattern and the correction resist pattern.

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