Measuring apparatus and method for measuring film thickness using relative heights in combination with refractive index

Patent metadata

Field	Value
Publication number	US-10845185-B2
Application number	US-201716473600-A
Country	US
Kind code	B2
Filing date	Nov 28, 2017
Priority date	Dec 27, 2016
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

There is provided a method of measuring a film thickness of a transparent material on a substrate. A first object (transparent material) is applied onto a first substrate surface, and a second object (transparent material) is applied onto a second substrate surface. The method includes: measuring a first relative height of a front surface of the first object with respect to the first substrate surface at a position without the first object; measuring a second relative height of the front surface with respect to a back surface of the first object; and calculating a refractive index of the transparent material, based on the first relative height and the second relative height. The method includes measuring a film thickness of the second object, using a third relative height of a front surface of the second object with respect to a back surface of the second object and the calculated refractive index.

First claim

The invention claimed is:

1. A measuring apparatus configured to measure a film thickness of an object of a transparent material applied onto a substrate surface, the measuring apparatus comprising:
a light source configured to emit white light;
an objective lens configured to separate the white light emitted from the light source into two beams, irradiate the object with one of the two beams and irradiate a reference surface with the other beam, and cause interference between light reflected from the object and light reflected from the reference surface, to thereby obtain interference light;
an imaging device configured to take an image of the interference light obtained by the objective lens;
a positioning device configured to move the objective lens in an optical axis direction relative to the object; and
a control device configured to control the light source, the imaging device and the positioning device, and measure a height of the object based on a peak intensity of the interference light in the image taken by the imaging device,
a first object being applied onto a first substrate surface, a second object being applied onto a second substrate surface,
the control device being configured to:
calculate a refractive index of the transparent material, based on a first relative height of a front surface of the first object with respect to the first substrate surface at a position where the first object is not applied and a second relative height of the front surface of the first object with respect to a back surface of the first object; and
measure a film thickness of the second object, using a third relative height of a front surface of the second object with respect to a back surface of the second object and the calculated refractive index.

2. The measuring apparatus according to claim 1 , wherein
the first substrate surface and the second substrate surface are on different substrates.

3. The measuring apparatus according to claim 1 , wherein
the first substrate surface and the second substrate surface are on the same substrate.

4. An application apparatus comprising:
an application mechanism configured to apply the transparent material onto the substrate surface; and
the measuring apparatus as recited in claim 1 .

5. The application apparatus according to claim 4 , wherein
the application mechanism includes an application needle,
the transparent material adheres to a tip portion of the application needle, and
the tip portion of the application needle or the transparent material adhering to the tip portion of the application needle is brought into contact with the substrate surface, to thereby apply the transparent material onto the substrate surface.

6. The application apparatus according to claim 5 , wherein
the control device is configured, after the transparent material is applied onto the second substrate surface by the application mechanism, to measure the film thickness of the second object, with the substrate remaining fixed.

7. The application apparatus according to claim 4 , wherein
the control device is configured, after the transparent material is applied onto the second substrate surface by the application mechanism, to measure the film thickness of the second object, with the substrate remaining fixed.

8. A method of measuring a film thickness of an object of a transparent material applied onto a substrate surface,
a first object being applied onto a first substrate surface, a second object being applied onto a second substrate surface,
the method comprising:
measuring a first relative height of a front surface of the first object with respect to the first substrate surface at a position where the first object is not applied;
measuring a second relative height of the front surface of the first object with respect to a back surface of the first object;
calculating a refractive index of the transparent material, based on the first relative height and the second relative height; and
measuring a film thickness of the second object, using a third relative height of a front surface of the second object with respect to a back surface of the second object and the calculated refractive index.

9. The method according to claim 8 , wherein
the first to third relative heights are measured using white-light interferometry.

Assignees

• Ntn Toyo Bearing Co Ltd

Inventors

• Ohba Hiroaki

Classifications

• G01N21/45

  using interferometric methods; using Schlieren methods · CPC title

• G01B11/0675 Primary

  using interferometry · CPC title

• G01B11/06

  for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)} · CPC title

• G01B11/0608

  Height gauges · CPC title

• B05C11/00

  Component parts, details or accessories not specifically provided for in groups B05C1/00 - B05C9/00 (means for manipulating or holding work B05C13/00; enclosures for apparatus, booths B05C15/00; spray booths B05B16/00) · CPC title