Measurement apparatus for measuring height or shape of a surface of a material

Patent metadata

Field	Value
Publication number	US-10845190-B2
Application number	US-201816114011-A
Country	US
Kind code	B2
Filing date	Aug 27, 2018
Priority date	Mar 5, 2018
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A measurement apparatus includes a filter changing a light amount of an irradiation light, a lens irradiating a surface of a material with the irradiation light, a stage changing a focus position of the irradiation light in a depth direction of the material, an interfering light extractor causing the irradiation light to interfere with reflected light from the material, a detector detecting an intensity of interfering light obtained by interference between the irradiation light and the reflected light, and a controller calculating a height of the surface of the material based on the detected intensity of interfering light while changing a relative focus position of the irradiation light with respect to the material at a given measurement point of the surface of the material. The controller controls the filter or light source based on the detected intensity of interfering light to change the light amount of the irradiation light.

First claim

What is claimed is:

1. A measurement apparatus comprising:
a light source configured to emit an irradiation light, a light emission amount of the irradiation light being changeable;
a filter configured to change a light pass amount of the irradiation light;
a lens configured to irradiate a surface of a material with the irradiation light, the material including a first layer and a second layer via an interface;
a stage configured to change a focus position of the irradiation light in the surface or the interface of the material in a plane direction and in a depth direction of the material;
an interfering light extractor, having a beam splitter and a mirror, configured to cause the irradiation light and reflected light from the material to interfere with each other;
a detector configured to detect an intensity of interfering light obtained by interference between the irradiation light and the reflected light, the detector having a lower detectable limit and an upper detectable limit; and
a controller configured to calculate a height of the surface or the interface of the material based on the intensity of interfering light detected by the detector while changing a relative focus position of the irradiation light with respect to the material at a given measurement point of the surface of the material in the plane direction and in the depth direction,
wherein
the controller performs
a plurality of first measurements along a first detection line in the plane direction while causing the stage to bring the focus position of the irradiation light to coincide with the surface of the material, and
a plurality of second measurements along a second detection line in the plane direction while causing the stage to bring the focus position of the irradiation light to coincide with the interface of the material, and

in each of the first measurements and in each of the second measurements,
if the intensity of interfering light detected by the detector exceeds the upper detectable limit, the controller controls the filter to decrease the light pass amount or control the light source to decrease the light emission amount, and
if the intensity of interfering light detected by the detector is smaller than the lower detectable limit, the controller controls the filter to increase the light pass amount or control the light source to increase the light emission amount.

2. The measurement apparatus according to claim 1 , wherein the controller controls the filter or the light source to bring mean intensities of the interfering light at respective measurement points of the material close to each other.

3. The measurement apparatus according to claim 1 , wherein the controller controls the filter or the light source to bring mean intensities of the interfering light at respective measurement points of the material approximately equal to each other.

4. The measurement apparatus according to claim 3 , further comprising a storage configured to store heights of the surface or the interface of the material calculated by the controller at a plurality of measurement points of the material, wherein the controller generates a shape of the surface or the interface of the material based on the heights of the surface or the interface of the material.

5. The measurement apparatus according to claim 4 , wherein the controller generates a two-dimensional shape of the surface or the interface of the material based on the heights of the surface or the interface of the material, and further generates a three-dimensional shape of the surface of the material based on a plurality of the two-dimensional shapes.

6. The measurement apparatus according to claim 4 , further comprising a display configured to display the shape of the surface or the interface of the material generated by the controller.

7. The measurement apparatus according to claim 1 , wherein the irradiation light is white color light.

8. The measurement apparatus according to claim 1 , wherein the controller determines that the focus position obtained when a peak occurs in the intensity of the interfering light is a position corresponding to the surface or the interface of the material.

Assignees

• Toshiba Memory Corp

Inventors

• Yoshino Kiminori

Classifications

• G01B9/0209

  Low-coherence interferometers · CPC title

• G01B11/2441 Primary

  using interferometry · CPC title

• G01M11/025

  by determining the shape of the object to be tested (measuring contours or curvatures by optical means G01B11/24) · CPC title

• G01B11/02

  for measuring length, width or thickness (G01B11/08 takes precedence) · CPC title

• G01M11/0271

  by using interferometric methods · CPC title