JPH10274839A - Correction mask and method for correcting halftone phase shifting mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove Cr film residual residue on a halftone film by using a correction mask having a light shielding pattern corresponding to a light shielding region other than the device region of a halftone phase shifting mask to be corrected. SOLUTION: This correction mask is provided with a light shielding film 3 in a region other than that corresponding to the device region 8, to make the device region 8 of the halftone phase shifting mask to be corrected 4 a translucent region, on a transparent substrate 1. In other words, when a positive photoresist 11 is used at the time of correcting the halftone phase shifting mask 4, the light shielding film 3 is provided in the region except one corresponding to the device region 8 on the transparent substrate 1, so that the device region 8 of the halftone phase shifting mask 4 becomes the translucent region. Thus, in a single correcting process, all defects, that is, all light shielding film recidus 10 can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repair mask and a method for repairing a halftone phase shift mask, and more particularly, to a method for efficiently removing a Cr film residue remaining on a halftone film. The present invention relates to a correction mask and a method for correcting a halftone phase shift mask.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a semiconductor device or the like, when patterning an insulating film or a conductive film, a photoresist is exposed using a photomask and then developed.
The insulating film or conductive film is patterned by etching using the developed photoresist pattern as a mask.

In this case, a photomask is formed on a quartz glass substrate, for example, by forming a C × 10 × 10 size of the actual pattern.
A working mask formed by forming a reticle provided with an r film pattern and subjecting the reticle to reduced exposure with a stepper, or a reticle for transferring a plurality of shots onto a wafer, and a semiconductor device using this photomask Exposure is performed in the manufacturing process.

[0004] With the recent increase in the degree of integration and the size of chips in semiconductor devices, photomasks and reticles have also been required to have higher precision, and as a result, coating of photosensitive materials that adversely affects dimensional accuracy has been required. Improvements have been attempted to minimize unevenness, uneven exposure, uneven development, or uneven etching.

As one of such improvements, a translucent halftone film is used in place of a photomask or a reticle using a Cr film, and a pattern edge portion is emphasized by utilizing a phase shift by the halftone film. Development of a halftone phase shift mask or a halftone phase shift reticle that forms a fine pattern by using the same has been developed.

[0006] The halftone phase shift mask in this specification means a halftone phase shift mask as a photomask used in a so-called photo process, and a master mask for forming the halftone phase shift mask used in the photo process. A broadly defined halftone phase shift mask that includes both commonly used halftone phase shift reticles.

In this halftone phase shift mask, the refractive index n and the thickness d of the halftone film satisfy the condition of d = λ / [2 (n−1)] with respect to the wavelength λ of light used for exposure. In the pattern edge portion, the light transmitted through the quartz glass substrate and the light transmitted through the halftone film cancel each other due to interference in the pattern edge portion, so that the light intensity in the vicinity of the pattern edge portion is substantially zero. ,
This emphasizes the pattern edge portion more than a conventional mask using an opaque pattern.

Here, a manufacturing process of a conventional halftone phase shift mask will be described with reference to FIGS. Referring to FIG. 4A, first, a MoSiON film 42 to be a halftone film is formed on a quartz glass substrate 41 by sputtering using an MoSi target in an atmosphere containing oxygen and nitrogen.
Is deposited, a Cr film 43 serving as a light-shielding film is deposited, and then an electron beam resist 44 is applied, and then exposed to a predetermined pattern by an electron beam to form an exposure region 45. In this case, the refractive index of the MoSiON film 42 is controlled by the concentrations of oxygen and nitrogen in the atmosphere.

Next, referring to FIG. 4 (b), using an electron beam resist pattern 46 formed by developing the positive electron beam resist 44 as a mask, ceric ammonium nitrate, perchloric acid, a surfactant and pure The Cr film 43 is patterned by etching using a mixture of water as an etchant to form a Cr film pattern 47.

Referring to FIG. 4C, after the electron beam resist pattern 46 is removed,
Dry etching using a mixed gas of CF ₄ , CHF _3, etc. and O ₂ using the Cr film pattern 47 as a mask,
By patterning the MoSiON film 42, M
An oSiON film pattern 48 is formed.

Next, as shown in FIG. 5D, ultraviolet irradiation, cleaning with dilute sulfuric acid and pure water, and
After performing cleaning by combining ultrasonic cleaning and baking, a positive type electron beam resist 49 and a conductive film 50 made of a conductive high molecular polymer for preventing charge-up are applied, and Cr is applied to the light shielding region 52. An exposure area 53 is formed by performing electron beam exposure so that the film pattern 47 remains.

The light-shielding region 52 in this case means a region other than the device region 51, and constitutes, for example, a region such as a scribe line portion or a reticle cover portion. If a plurality of shots are transferred by using such a halftone phase shift mask without the 47 remaining, the scribe line or the reticle cover portion is subjected to multiple exposures, and undesired resist thinning occurs due to light interference. Will be.

Referring to FIG. 5E, the electron beam resist 49 is developed to form an electron beam resist mask 54. Using the electron beam resist mask 54 as a mask, ceric ammonium nitrate, perchloric acid, surfactant The Cr film pattern 47 on the MoSiON film pattern 48 in the device region 51 is removed by performing wet etching using a mixture of the agent and pure water as an etchant.

Next, by removing the electron beam resist pattern 54, a halftone film pattern consisting of only the MoSiON film pattern 48 remains in the device region 51, and in the surrounding light-shielding region 52, as shown in FIG. Cr film pattern 4
The halftone phase shift mask 55 in which 7 remains is completed.

However, in such a halftone phase shift mask, there is a problem that a resist residue or a foreign substance in a patterning step of the Cr film becomes a mask and a Cr film residue is generated. 6 and FIG.

6 (a) and 6 (b) FIG. 6 (a) is a cross-sectional view taken along a dashed line connecting AA 'in the plan view of the halftone phase shift mask shown in FIG. 6 (b). Yes, in part of the device area 51, MoS
Cr film residues 57 and 58 are partially formed on the iON film pattern 48.
Indicates a situation in which is occurring.

With respect to such Cr film residues 57 and 58, the light-shielding portion and the light-transmitting portion are binarized to form the light-transmitting region 56.
In the hard defect inspection method in which pattern defects are inspected by comparing pattern data with design data in which the light-transmitting portion is used and the other region is a light-shielding portion, Cr film residues 57 and 58 are present on the MoSiON film pattern 48 which is a light-shielding portion. Since it is determined that the light-shielding portion is present or not, the Cr film residues 57 and 58 cannot be detected.
7, 58 are detected.

Referring to FIG. 7, as a result of such a surface foreign matter inspection, a photoresist is applied to the entire surface of the halftone phase shift mask 55 in which the Cr film residues 57 and 58 are detected in order to remove the Cr film residues 57 and 58. After the application, spot exposure is performed on the regions where the Cr film residues 57 and 58 are present, and a photoresist mask 59 is formed by development, and ceric ammonium nitrate, perchloric acid, a surfactant, By performing wet etching using a mixed solution of pure water as an etchant, Cr film residues 57 and 5 are formed.
8 is removed.

It should be noted that the resist residue and foreign matter that caused the generation of the Cr film residues 57 and 58 are almost 100% removed in the above-described cleaning step of FIG. 5D. In the surface foreign matter inspection step, it is possible to distinguish between the Cr film residues 57, 58 and the resist residues and foreign matters on the Cr film residues 57, 58. Therefore, the halftone phase shift mask from which the resist residues and foreign matters are not removed is defective. Discard as

[0020]

However, the improvement in the degree of integration in recent semiconductor devices, the increase in pattern density due to miniaturization, and the adoption of a dry etching process have increased the incidence of pattern defects. The number of times of performing is increased, which is a problem in turn.

In the case where the pattern density is low and the wet etching process is used, the number of defective portions is small. There were few places themselves.

Accordingly, it is an object of the present invention to correct a plurality of defects generated in a halftone phase shift mask by one correction operation.

[0023]

FIG. 1 is an explanatory view of the principle configuration of the present invention. Referring to FIG. 1, means for solving the problems in the present invention will be described. See FIG. 1 (1) In the repair mask, the present invention corresponds to the device region 8 on the transparent substrate 1 such that the device region 8 of the halftone phase shift mask 4 to be repaired becomes a light-transmitting region. The light shielding film 3 is provided in a region other than the region.

When a positive resist 11 is used for repairing the halftone phase shift mask 4, the transparent substrate 1 is formed such that the device region 8 of the halftone phase shift mask 4 becomes a translucent region. By providing the light-shielding film 3 in a region other than the region corresponding to the device region 8, all defects, that is, all the light-shielding film residues 10 can be removed in one repair process.

(2) The present invention relates to a repair mask,
The light-shielding film 3 is provided on the transparent substrate 1 in a region corresponding to the device region 8 so that the device region 8 of the halftone phase shift mask 4 to be corrected becomes a light-shielding region.

When a negative resist is used for repairing the halftone phase shift mask 4, the device region 8 of the transparent substrate 1 is set so that the device region 8 of the halftone phase shift mask 4 becomes a light-shielding region. By providing the light-shielding film 3 in a region corresponding to the above, all the defects, that is, all the light-shielding film residues 10 can be removed in one repair process.

(3) According to the present invention, in the method of correcting a halftone phase shift mask, the resist 11 provided on the halftone phase shift mask 4 is exposed by using the correction mask 1 of the above (1) or (2). The light-shielding film residue 10 remaining on the halftone film 6 in the device region 8 is formed using a resist mask formed by developing the resist 11 as a mask.
Is removed by etching.

As described above, by using the correction mask 1 of the above (1) or (2), the resist mask can be left only in the region where the light shielding film 3 needs to be left. Thereby, all the defects, that is, all the light-shielding film residues 10 can be removed in one repairing step, so that the manufacturing steps and the manufacturing yield are improved.

(4) In the present invention, in the above (3), the halftone film 6 is a MoSiON film, and
The light shielding film residue 10 is a Cr film residue.

Since such a combination of the MoSiON film and the Cr film has a high selective etching property with respect to both the wet etching liquid and the dry etching gas,
Selective removal of film or Cr film residues is facilitated.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, a first embodiment of the present invention will be described with reference to FIG. Referring to FIG. 2A, first, as shown in FIG. 6 described above, a Cr film is formed on the MoSiON film pattern 22 serving as a halftone film in the device region 25.
Halftone phase shift mask 2 having film residue 27
After applying a positive photoresist 28 on the entire surface of No. 4,
On a quartz glass substrate 29, a C to be a light shielding film is formed at a position corresponding to the light shielding region 26 of the halftone phase shift mask 24.
Exposure is performed with ultraviolet light 32 using a correction mask 31 provided with an r film pattern 30.

Next, after the positive photoresist 28 is developed to form a resist mask 33, ceric ammonium nitrate, perchloric acid, a surfactant, Then, the Cr film residue 27 is removed by performing wet etching using a mixed solution of pure water as an etchant.

Next, by removing the resist mask 33, as shown in FIG.
In the device region 25, the halftone film pattern composed of only the MoSiON film pattern 22 remains, and in the surrounding light shielding region 26, the Cr film pattern 23 remains, and the correction of the halftone phase shift mask 24 is completed.

As described above, in the first embodiment of the present invention, the correction is performed using the correction mask 31 provided with the Cr film pattern 30 corresponding to the light shielding region 26 where the Cr film pattern 23 needs to remain. Is performed, the entire device region 25 can be exposed by a single process. Therefore, even if a plurality of Cr film residues 27 exist in the device region 25, all the Cr regions can be exposed by a single etching process. The film residue 27 can be reliably removed, and the repair process is simplified.

In this case, in the manufacturing process of the repair mask 31, a positive type electron beam resist is used as a resist, and the device region 25 is formed as shown in FIG. Exposure is performed using the electron beam exposure data used in the step of removing the Cr film pattern as described above, so that C
The r film pattern 30 can be easily formed.

Further, such a correction mask 31 corresponds to the M of the device region 25 of the halftone phase shift mask 24.
Even if the shapes of the oSiON film patterns 22 are different from each other, if the appearance of the halftone phase shift mask 24 is the same, one correction mask 31 is commonly used for various halftone phase shift masks. be able to.

Next, a second embodiment of the present invention will be described with reference to FIG. Referring to FIG. 3, the second embodiment is a case where a negative photoresist is used in the repairing process, and the MoSiON film pattern 2 serving as a halftone film in the device region 25 is used.
After a negative photoresist 34 is applied to the entire surface of the halftone phase shift mask 24 having the Cr film residue 27 on the surface 2, a position corresponding to the device region 25 of the halftone phase shift mask 24 is placed on the quartz glass substrate 35. Then, exposure is performed by ultraviolet rays 32 using a correction mask 37 provided with a Cr film pattern 36 serving as a light shielding film.

Although not shown hereafter, similarly to the first embodiment, after developing the negative photoresist 34 to form a resist mask, the resist mask is used as a mask to form ceric ammonium nitrate, The halftone phase shift mask 2 is formed by performing wet etching using a mixed solution of perchloric acid, a surfactant, and pure water as an etchant to remove the Cr film residue 27.
Modify 4

Also in this case, as in the first embodiment, all of the device region 25 can be exposed by one process, so that a plurality of Cr film residues 27 exist in the device region 25. Also, all the Cr film residues 27 can be reliably removed by a single etching process, and the repair process is simplified.

In this case, in the manufacturing process of the repair mask 37, a negative type electron beam resist is used as the repair mask 37, and the device region 25 is formed as shown in FIG. Exposure using the electron beam exposure data used in the step of removing the Cr film pattern of
The r film pattern 36 can be easily formed.

The embodiments of the present invention have been described above. However, the present invention is not limited to the manufacturing conditions and embodiments described in the embodiments.
It is not limited to the manufacturing process, and various changes are possible.

For example, in the description of the above embodiments, in the step of patterning the Cr film and removing the Cr film, a mixed solution of ceric ammonium nitrate, perchloric acid, a surfactant, and pure water is used. Is used as an etchant, but a dry etching method using a mixed gas of Cl ₂ + O ₂ or a mixed gas of HCl ₃ + O ₂ may be used.

In the description of each of the above embodiments, a MoSiON film having good selectivity with a Cr film in both dry etching and wet etching is used as a halftone film. M
The film is not limited to the oSiON film, and a CrON film may be used. In this case, since the selective etching property with the Cr film is lowered, it is necessary to use a metal film other than the Cr film as the light shielding film. .

[0044]

According to the present invention, a halftone phase shift mask to be repaired using a repair mask having a light shielding pattern corresponding to a light shielding region other than the device region of the halftone phase shift mask to be repaired. Since a photoresist mask pattern for correction etching is formed thereon, the Cr film residue on the halftone film can be effectively removed in a single step. It greatly contributes to the improvement of manufacturing yield.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of the present invention.

FIG. 2 is an explanatory diagram of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory view of a manufacturing process of a halftone phase shift mask according to the related art.

FIG. 5 is an explanatory diagram of a manufacturing process of the conventional halftone phase shift mask after FIG. 4;

FIG. 6 is an explanatory diagram of a problem of a conventional halftone phase shift mask.

FIG. 7 is an explanatory diagram of a conventional halftone phase shift mask correction method.

DESCRIPTION OF SYMBOLS 1 Correction mask 2 Transparent substrate 3 Light shielding film 4 Halftone phase shift mask 5 Transparent substrate 6 Halftone film 7 Light shielding film 8 Device region 9 Light shielding region 10 Light shielding film residue 11 Resist 12 Exposure light 21 Quartz glass Substrate 22 MoSiON film pattern 23 Cr film pattern 24 Halftone phase shift mask 25 Device region 26 Light shielding region 27 Cr film residue 28 Positive photoresist 29 Quartz glass substrate 30 Cr film pattern 31 Correction mask 32 Ultraviolet 33 Resist mask 34 Negative Photoresist 35 Quartz glass substrate 36 Cr film pattern 37 Correction mask 41 Quartz glass substrate 42 MoSiON film 43 Cr film 44 Electron beam resist 45 Exposure area 46 Electron beam resist pattern 47 Cr film pattern 48 Mo iON layer pattern 49 electron beam resist 50 conductive film 51 device regions 52 electron beam resist pattern light shielding region 53 exposed area 54 55 halftone phase shift mask 56 translucent regions 57 Cr Makuzan渣 58 Cr Makuzan渣 59 photoresist mask

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H01L 21/30 528

Claims (4)

[Claims] 1. A light-shielding film is provided on a transparent substrate in a region other than a region corresponding to the device region, such that a device region of the halftone phase shift mask to be corrected is a light-transmitting region. Correction mask. 2. A correction film, wherein a light-shielding film is provided on a transparent substrate in a region corresponding to the device region, such that a device region of the halftone phase shift mask to be corrected is a light-shielding region. mask. 3. A half of a device region is formed by exposing a resist provided on a halftone phase shift mask using the correction mask according to claim 1 and developing the resist and using the resist mask as a mask. A method for repairing a halftone phase shift mask, which comprises removing a light shielding film residue remaining on a tone film by etching. 4. The method of repairing a halftone phase shift mask according to claim 3, wherein said halftone film is a MoSiON film, and said light shielding film residue is a Cr film residue.