Method of deciding measurement value

• US 20060109486A1
• Filed: 11/10/2005
• Published: 05/25/2006
• Est. Priority Date: 11/19/2004
• Status: Active Grant

• Current Assignee: Holon Co., Ltd. (A&D Company Limited)
• Original Assignee: Holon Co., Ltd. (A&D Company Limited)
• Inventors: Anazawa, Norimichi, Nitta, Jun, Takahashi, Katuyuki
• Granted Patent: US 7,409,309 B2
• Time in Patent Office: Days
• US Class Current: 356/636
• CPC Class Codes: G01B 15/00 Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons characterised by the use of optical techniques G01B9/00, G01B11/00
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness

Abstract

A method of deciding a measurement value as decides the quality of the measurement value of the line width, the line interval or the like of a pattern on an object to-be-measured, comprising the steps of acquiring the signal intensity distribution of the pattern on the object to-be-measured (2 in FIG. 1), detecting the edge positions of the pattern from the acquired signal intensity distribution, detecting the taper widths of the edge parts of the pattern from the acquired signal intensity distribution, and deciding that the measurement value calculated on the basis of the detected edge positions is correct, when the detected taper widths fall within a predetermined range set beforehand. In this way, it is permitted to automatically decide the defective measurement of the line width of the pattern, or the like, attributed to an unclear image due to inferior focusing in an image photographing mode, an unclear image due to an image drift ascribable to charging-up, or the like.

Claims

1. A method of deciding a measurement value for deciding a quality of the measurement value of a line width, a line interval or the like of a pattern on an object to-be-measured, comprising the steps of:

acquiring a signal intensity distribution of the pattern on the object to-be-measured;

detecting edge positions of the pattern from the acquired signal intensity distribution;

detecting taper widths of edge parts of the pattern from the acquired signal intensity distribution; and

deciding that the measurement value calculated on the basis of the detected edge positions is correct, when the detected taper widths fall within a predetermined range set beforehand, and that the measurement value calculated on the basis of the detected edge positions is defective, when the detected taper widths fall outside the predetermined range.

2. A method of deciding a measurement value as defined in claim 1, wherein each of the taper widths is a width between a maximum peak value P1 and a minimum peak value P2 which correspond to the edge part of the signal intensity distribution.

3. A method of deciding a measurement value as defined in claim 1, wherein each of the taper widths is a width between two threshold values which are previously set between a maximum peak value P1 and a minimum peak value P2 corresponding to the edge part of the signal intensity distribution.

4. A method of deciding a measurement value as defined in claim 1, wherein each of the edge positions of the pattern is a position between a maximum peak value P1 and a minimum peak value P2 which correspond to the edge part of the signal intensity distribution.

5. A method of deciding a measurement value as defined in claim 3, wherein each of the edge positions of the pattern is a position between two threshold values which are previously set between a maximum peak value P1 and a minimum peak value P2 corresponding to the edge part of the signal intensity distribution.

6. A method of deciding a measurement value as defined in claim 3, wherein each of the edge positions of the pattern is found by a linear regression method on the basis of a predetermined number of values between a maximum peak value P1 and a minimum peak value P2 which correspond to the edge part of the signal intensity distribution.

7. A method of deciding a measurement value as defined in claim 6, wherein the signal intensity distribution of the pattern is a signal intensity distribution which is generated by detecting secondary electrons emitted from the pattern on the object to-be-measured.

8. A method of deciding a measurement value as defined in claim 7, wherein the measurement value of the pattern calculated on the basis of the edge positions is output together with a result of the decision as to whether the measurement value decided on the basis of values of the taper widths or slope values is correct or defective.

9. A method of deciding a measurement value as defined in claim 8, wherein the signal intensity distribution is at least one signal intensity distribution which has been obtained by scanning the object to-be-measured with an electron beam spot.

10. A method of deciding a measurement value as defined in claim 8, wherein the values of the taper widths or the slope values corresponding to a position of the pattern are output together.

11. A method of deciding a measurement value as defined in claim 10, wherein the values of the taper widths or the slope values are output every creation condition or drawing condition of the pattern.