Method and system of defect inspection for mask blank and method of manufacturing semiconductor device using the same

Abstract

Defect detection is performed with two settings, that is, setting of a focus position where a signal intensity obtained from a dot pattern is maximum and setting of a focus position where a signal intensity obtained from a hole pattern is maximum. In addition, defect detection is performed at a predetermined focus position previously set and for the detected defect, the focus position is changed at that position to find a focus position where the signal intensity is maximum. If the focus position is away from a signal light-receiving system, the defect is determined as dot-shaped. If the focus position is close to the signal light-receiving system, the defect is determined as hole-shaped. If the focus position is intermediate of them, the defect is determined as an elongated-shaped.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a schematic diagram of a configuration and operation of a mask blank defect inspection system according to a first embodiment of the present invention;

FIG. 2A is a diagram for describing a concept of a defect inspection method in the mask blank defect inspection system according to the first embodiment of the present invention;

FIG. 2B is a diagram for describing the concept of the defect inspection method in the mask blank defect inspection system according to the first embodiment of the present invention;

FIG. 2C is a diagram for describing the concept of the defect inspection method in the mask blank defect inspection system according to the first embodiment of the present invention;

FIG. 3 is a characteristic diagram depicting characteristics of defect signals in the mask blank defect inspection system according to the first embodiment of the present invention;

FIG. 4 is a process flow diagram of an implementing process of a defect inspection method in the mask blank defect inspection system and method according to the first embodiment of the present invention;

FIG. 5 is a process flow diagram of an implementing process of a defect inspection method in a mask blank defect inspection system and method according to a second embodiment of the present invention;

FIG. 6 is a process flow diagram of an implementing process of a defect inspection method in a mask blank defect inspection system and method according to a third embodiment of the present invention;

FIG. 7A is a sectional view of main parts that depicts a semiconductor device manufacturing process according to a fourth embodiment of the present invention;

FIG. 7B is a sectional view of main parts that depicts the semiconductor device manufacturing process according to the fourth embodiment of the present invention;

FIG. 7C is a sectional view of main parts that depicts the semiconductor device manufacturing process according to the fourth embodiment of the present invention;

FIG. 7D is a sectional view of main parts that depicts the semiconductor device manufacturing process according to the fourth embodiment of the present invention;

FIG. 7E is a sectional view of main parts that depicts the semiconductor device manufacturing process according to the fourth embodiment of the present invention; and

FIG. 7F is a sectional view of main parts that depicts the semiconductor device manufacturing process according to the fourth embodiment of the present invention.

Claims

1. A method for mask blank defect inspection comprising: a first step including: radiation on a first mask blank having formed thereon a dot pattern serving as a reference with extreme ultraviolet light; and obtainment of a first focus position where a signal intensity of a first darkfield detection image produced by the scatter-reflected light is maximum;a second step including: radiation at the first focus position on a second mask blank, which is an inspection target with extreme ultraviolet light; scanning on the second mask blank in a direction perpendicular to an optical axis of the scatter-reflected light; and detection of a signal intensity of a second darkfield detection image produced by the scatter-reflected light; anda third step including detection of a defect in the second mask blank based on the signal intensity of the second darkfield detection image.

2. The method for mask blank defect inspection according to claim 1, further comprising: a fourth step including: radiation on a third mask blank having formed thereon a hole pattern serving as a reference with extreme ultraviolet light; and obtainment of a second focus position where a signal intensity of a third darkfield detection image produced by the scatter-reflected light is maximum; anda fifth step including: radiation at the second focus position on the second mask blank, which is an inspection target with extreme ultraviolet light, scanning on the second mask blank in a direction perpendicular to an optical axis of the scatter-reflected light, and detection of a signal intensity of a fourth darkfield detection image produced by the scatter-reflected light,wherein, in the third step, a defect in the second mask blank is detected based on the signal intensities of the second and fourth darkfield detection images.

3. The method for mask blank defect inspection according to claim 2, wherein, in the third step, when the signal intensity of the fourth darkfield detection image at the second focus position is larger than the signal intensity of the second darkfield detection image at the first focus position, the defect is determined as a hole-shaped defect.

4. The method for mask blank defect inspection according to claim 1, further comprising: a sixth step including: radiation on a surface of a glass substrate, which is a base of the second mask blank with any one or all of visible light, ultraviolet light, and far-ultraviolet light; detection of a defect on the glass substrate by using reflected light; and extraction of a glass substrate which has a value of defects equal to or smaller than a specified value; anda seventh step including: formation of the second mask blank by making a multilayer adhere to the glass substrate which has a value of defects equal to or smaller than the specified value.

5. A method for mask blank defect inspection comprising: an eighth step including: radiation on a fourth mask blank having formed thereon a line pattern serving as a reference with extreme ultraviolet light; and obtainment of a third focus position where a signal intensity of a fifth darkfield detection image produced by the scatter-reflected light is maximum;a ninth step including: radiation at the third focus position on a second mask blank, which is an inspection target with extreme ultraviolet light; scanning on the second mask blank in a direction perpendicular to an optical axis of the scatter-reflected light; and detection of a signal intensity of a sixth darkfield detection image produced by the scatter-reflected light;a tenth step including detection of a defect position in the second mask blank based on the signal intensity of the sixth darkfield detection image;an eleventh step including: radiation on the second mask blank with extreme ultraviolet light while changing the focus position at the defect position; and detection of a signal intensity of a seventh darkfield detection image produced by the scatter-reflected light;a twelfth step of obtaining a fourth focus position where a signal intensity of the seventh darkfield detection image is maximum; anda thirteenth step of determining a type of the defect in the second mask blank based on the third and fourth focus positions.

6. The method for mask blank defect inspection according to claim 5, wherein, in the thirteenth step, the defect is determined as a dot-shaped defect when the fourth focus position is away from a signal light-receiving system compared to the third focus position, the defect is determined as a hole-shaped defect when the fourth focus position is closer thereto, and the defect is determined as a line-shaped defect when the fourth focus position is closer to the third focus position.

7. The method for mask blank defect inspection according to claim 1, wherein the second mask blank is a multilayer mask blank.

8. A system for mask blank defect inspection comprising: a stage movable in X-axis, Y-axis, and Z-axis directions;an irradiator that radiates a mask blank on the stage with extreme ultraviolet light;a detector that detects a darkfield detection image produced by the scatter-reflected light from the mask blank; andan analyzing device that detects a defect in the mask blank based on a position of the stage and a signal intensity of the darkfield detection image,wherein the analyzing device has a function of implementing the method for mask blank defect inspection according to claim 1.

9. A method of manufacturing a semiconductor device comprising: a step of implementing the method for mask blank defect inspection according to claim 1; anda step of manufacturing a semiconductor device by using a mask blank determined as having a value of defects equal to or smaller than the specified value in the step of mask blank defect inspection.

10. The method of manufacturing a semiconductor device according to claim 9, wherein the step of manufacturing a semiconductor device includes any one or all of: a gate forming step; a connection-layer forming step; and a first-layer-wiring forming step, andin any one or all of: the gate forming step; the connection-layer forming step; and the first-layer-wiring forming step, the mask blank determined as having a value of defects equal to or smaller than the specified value is used.