Measuring method, data processing apparatus and electron microscope using same

Patent metadata

Field	Value
Publication number	US-9305744-B2
Application number	US-201214349375-A
Country	US
Kind code	B2
Filing date	Sep 27, 2012
Priority date	Oct 6, 2011
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

The objective of the invention is to provide a measuring method that can determine pattern contours and dimensions with high precision even if an object to be measured shrinks due to electron beam radiations. In order to achieve this objective, a method, which performs measurements by irradiating an electron beam onto a sample having a pattern formed on a primary coating thereof, prepares an SEM image and contour of the pattern (S 201 , S 202 ), material parameters of the pattern part and primary coating part of the sample (S 203 , S 204 ), and a beam condition in irradiating the electron beam onto the sample (S 205 ), and uses these prepared things to calculate a pattern shape or dimensions before the irradiation of the electron beam (S 206 ).

First claim

The invention claimed is:

1. A method of measuring a pattern formed on a sample including a wafer and a primary coating layer formed on the wafer, by irradiating a charged particle beam onto the sample, the pattern being formed on the primary coating layer using a material which is different from the material of the primary coating layer so that the primary coating layer is positioned between the pattern and the wafer, the method comprising:
a step of preparing data including a pattern shape of the sample acquired while the charged particle beam is irradiating or after it has been irradiated onto the sample;
a step of preparing a parameter relating to shrink of a pattern part of the sample;
a step of preparing a parameter relating to shrink of a primary coating layer part of the sample;
a step of preparing a beam condition when irradiating the charged particle beam onto the sample, and
a step of calculating the pattern shape or dimension of the sample before irradiating the charged particle beam onto the sample by using the data including the pattern shape, the parameter relating to shrink of the pattern part, the parameter relating to shrink of the primary coating layer part, and the beam condition.

2. The measuring method according to claim 1 ,
wherein the pattern is a pattern formed by a resist, and
the pattern shape or dimension of the sample before irradiating the charged particle beam onto the sample is a pre-shrinking shape or dimension of the pattern.

3. The measuring method according to claim 2 , further comprising:
a step of displaying shrinkage of the pattern.

4. The measuring method according to claim 3 , further comprising:
a step of deciding whether the shrinkage of the pattern exceeds a prescribed value or not.

5. The measuring method according to claim 1 , wherein the steps of preparing the parameters relating to shrinks of the pattern part and the primary coating layer part utilize a database which saves shrink parameters of a plurality of materials.

6. The measuring method according to claim 1 , wherein the data including the pattern shape of the sample acquired while the charged particle beam is irradiating or after it has been irradiated onto the sample is an electron microscope image acquired using an electron microscope for the sample or contour line data extracted from the electron microscope image.

7. The measuring method according to claim 1 , wherein the pattern shape is a sectional shape of the pattern.

8. The measuring method according to claim 1 , wherein the step of preparing the data including the pattern shape of the sample includes a step of correcting an error in the pattern shape or dimension caused by charging of the sample.

9. The measuring method according to claim 8 , wherein, in the step of correcting the error in shape or dimension caused by charging of the sample, an algorithm utilizing asymmetry of a profile of image luminance is used.

10. The measuring method according to claim 1 , wherein the parameter relating to shrink of the pattern part and the parameter relating to shrink of the primary coating layer part are parameters determined from shrinkages of a plurality of line patterns which are different in line width.

11. A data processing apparatus that processes data including information of a shape of a pattern formed on a sample including a wafer and a primary coating layer formed on the wafer, the pattern being formed on the primary coating layer using a material which is different from the material of the primary coating, so that the primary coating layer is positioned between the pattern and the wafer, comprising:
a data saving means;
a material parameter saving means; and
a shrink arithmetic operation unit,
wherein the image saving means is adapted to save image data that the sample has been photographed,
the material parameter saving means is adapted to save a shrink parameter of a pattern part of the sample and a shrink parameter of a primary coating layer part of the sample, and
the shrink arithmetic operation unit is adapted to calculate a pattern shape before a charged particle beam is irradiated onto the sample or a pattern shape after the charged particle beam has been irradiated onto the sample by using the image data, the shrink parameter of the pattern part, and the shrink parameter of the primary coating layer part.

12. An electron microscope, comprising:
the data processing apparatus according to claim 11 ;
an electron source;
an optical system adapted to irradiate an electron emitted from the electron source onto the sample;
a detector that detects the electron emitted from the sample; and
an apparatus control unit that controls them,
wherein the data processing apparatus is adapted to calculate a pattern shape before an electron beam is irradiated onto the sample or a pattern shape after the electron beam has been irradiated onto the sample.

13. The electron microscope according to claim 12 ,
wherein the image data is image data of the electron microscope acquired by observing the sample through an electron beam microscope,
the data processing apparatus further has a means for extracting contour data from the image data of the electron microscope, and
the shrink arithmetic operation unit is adapted to calculate a pattern shape before observation through the electron microscope by using the contour data in place of the image data.

14. A method of measuring a pattern formed on a sample including a wafer and a primary coating layer formed on the wafer, the pattern being formed on the primary coating layer using a material different from the material of the primary coating layer so that the primary coating layer is positioned between the pattern and the wafer, comprising:
a step of preparing pattern data of the sample before a charged particle beam is irradiated onto it;
a step of preparing a parameter relating to shrink of a pattern part of the sample;
a step of preparing a parameter relating to shrink of a primary coating layer part of the sample;
a step of preparing a beam condition when measuring the pattern of the sample by using the charged particle beam, and
a step of calculating a pattern shape or dimension obtained when measuring it by irradiating the charged particle beam of the beam condition onto the sample by using the pattern data before the charged particle beam is irradiated, the parameter relating to shrink of the pattern part, the parameter relating to shrink of the primary coating layer part, and the beam condition.

15. The measuring method according to claim 14 , further comprising:
a step of displaying shrinkage of the pattern generated when measuring it by irradiating the charged particle beam of the beam condition onto the sample.

16. The measuring method according to claim 14 , further comprising:
a step of searching for the beam condition such that shrinkage of the pattern generated when measuring it by irradiating the charged particle beam of the beam condition onto the sample becomes not more than a prescribed value.

17. The measuring method according to claim 14 , wherein the pattern data is data of a sectional shape of the pattern.

18. The measuring method according to claim 14 ,
wherein the pattern shape obtained when measuring it by irradiating the charged particle beam of the beam condition onto the sample is a solid shape of the pattern, and comprising:
a step of inputting an electron microscope image acquired by using an electron microscope for the sample, and
a step of extracting the shape of the pattern from the el

Assignees

• Hitachi High Tech Corp

Inventors

• Ohashi Takeyoshi
• Tanaka Junichi
• Sekiguchi Tomoko
• Kawada Hiroki

Classifications

• G01B2210/56

  Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth · CPC title

• H01J2237/2817

  Pattern inspection · CPC title

• H01J37/28 Primary

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title

• G01N23/22 Primary

  by measuring secondary emission from the material · CPC title

• H01J2237/24578

  Spatial variables, e.g. position, distance · CPC title