CURVATURE MEASUREMENT APPARATUS AND METHOD

• US 20150276388A1
• Filed: 03/27/2015
• Published: 10/01/2015
• Est. Priority Date: 03/27/2014
• Status: Active Grant

• Current Assignee: NuFlare Technology, Inc. (Toshiba Corporation)
• Original Assignee: NuFlare Technology, Inc. (Toshiba Corporation)
• Inventors: AKITA, Masato, IYECHIKA, Yasushi
• Granted Patent: US 9,453,721 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 11/16 for measuring the deformation in a solid, e.g. optical strain gauge
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01B 11/255 for measuring radius of curvature measuring diameter G01B11/08
• CPC Class Codes: H01L 21/67288 Monitoring of warpage, curvature, damage, defects or the like
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14

Abstract

A curvature measurement apparatus according to an embodiment includes: a laser beam emitting portion emitting a laser beam; a first polarization beam splitter separating the emitted laser beam into first and second laser beams in different polarization directions and in different travel directions; a mirror reflecting the first laser beam so that the first and second laser beams travel side by side to a substrate; a second polarization beam splitter transmitting the second laser beam mirror-reflected from the substrate and reflecting the first laser beam, mirror-reflected from the substrate, in a direction different from a travel direction of the second laser beam; a one-dimensional first position detection device detecting an incident position of the reflected first laser beam on the first position detection device; and a one-dimensional second position detection device detecting an incident position of the transmitted second laser beam on the second position detection device.

Claims

1. A curvature measurement apparatus, comprising:

a light emitting portion configured to emit a laser beam;

a first polarization beam splitter configured to separate the laser beam emitted from the light emitting portion into a first laser beam and a second laser beam which are in different polarization directions and in different travel directions;

a reflection portion configured to reflect any one of the first and second laser beams so that the first and second laser beams travel side by side to a measurement object;

a second polarization beam splitter configured to transmit any one of the first and second laser beams mirror-reflected from the measurement object, and to reflect the other laser beam in a direction different from a travel direction of the one laser beam;

a one-dimensional first position detection device configured to detect an incident position where the first laser beam reflected from or transmitted through the second polarization beam splitter is incident on the first position detection device; and

a one-dimensional second position detection device configured to detect an incident position where the second laser beam transmitted through or reflected from the second polarization beam splitter is incident on the second position detection device.

5. The curvature measurement apparatus according to claim 1, further comprising a calculation portion configured to calculate a difference between a displacement of the incident position of the first laser beam detected by the first position detection device and a displacement of the incident position of the second laser beam detected by the second position detection device, and calculate a curvature change of the measurement object based on a correlation between the calculated difference and the optical path lengths of the first and second laser beams.

7. The curvature measurement apparatus according to claim 1, wherein the first position detection device and the second position detection devices detect a change in a shortest distance between two line segments of the first and second laser beams reflected from the measurement object.

9. The curvature measurement apparatus according to claim 1, further comprising a condenser lens configured to focus the first laser beam onto the first position detection device in a direction perpendicular to an element array direction of the first position detection device, and to focus the second laser beam onto the second position detection device in a direction perpendicular to an element array direction of the second position detection device.

11. The curvature measurement apparatus according to claim 1, wherein the laser beam emitted by the light emitting portion emits is a laser beam with a wavelength of 700 nm or less.

13. The curvature measurement apparatus according to claim 1, wherein

the first position detection device includes a first light receiving surface on which the first laser beam is incident,

a normal direction to the first light receiving surface is inclined at least at 10 degrees with respect to the optical axis of the first laser beam,

the second position detection device includes a second light receiving surface on which the second laser beam is incident, and

a normal direction to the second light receiving surface is inclined at least at 10 degrees with respect to the optical axis of the second laser beam.

15. The curvature measurement apparatus according to claim 1, further comprising a shaping portion configured to expand the first laser beam in a direction perpendicular to an element array direction of the first position detection device, and to expand the second laser beam in a direction perpendicular to an element array direction of the second position detection device.

2. A curvature measurement apparatus, comprising:

a light emitting portion configured to emit a laser beam;

a first polarization beam splitter configured to separate the laser beam emitted from the light emitting portion into a first laser beam and a second laser beam which are in different polarization directions and in different travel directions;

a reflection portion configured to reflect the second laser beam so that the first and second laser beams travel side by side to a measurement object;

a second polarization beam splitter configured to transmit any one of the first and second laser beams traveling toward the measurement object;

a quarter-wave plate through which the first and second laser beams traveling toward the measurement object pass, and through which the first and second laser beams mirror-reflected from the measurement object pass;

a first position detection device configured to detect an incident position where the first laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is incident on the first position detection device; and

a second position detection device configured to detect an incident position where the second laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is incident on the second position detection device.

3. The curvature measurement apparatus according to claim 2, wherein

in a case where the first laser beam traveling toward the measurement object is transmitted through the second polarization beam splitter,

the second polarization beam splitter reflects the first laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate,

the reflection portion reflects the second laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate,

the first position detection device detects the incident position where the first laser beam reflected from the second polarization beam splitter is incident on the first position detection device, and

the second position detection device detects the incident position where the second laser beam reflected from the reflection portion is incident on the second position detection device.

4. The curvature measurement apparatus according to claim 2, wherein

in a case where the second laser beam traveling toward the measurement object is transmitted through the second polarization beam splitter,

the first polarization beam splitter reflects the first laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate,

the second polarization beam splitter reflects the second laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate,

the first position detection device detects the incident position where the first laser beam reflected from the first polarization beam splitter is incident on the first position detection device, and

the second position detection device detects the incident position where the second laser beam reflected from the second polarization beam splitter is incident on the second position detection device.

6. The curvature measurement apparatus according to claim 2, further comprising a calculation portion configured to calculate a difference between a displacement of the incident position of the first laser beam detected by the first position detection device and a displacement of the incident position of the second laser beam detected by the second position detection device, and calculate a curvature change of the measurement object based on a correlation between the calculated difference and the optical path lengths of the first and second laser beams.

8. The curvature measurement apparatus according to claim 2, wherein the first position detection device and the second position detection devices detect a change in a shortest distance between two line segments of the first and second laser beams reflected from the measurement object.

10. The curvature measurement apparatus according to claim 2, further comprising a condenser lens configured to focus the first laser beam onto the first position detection device in a direction perpendicular to an element array direction of the first position detection device, and to focus the second laser beam onto the second position detection device in a direction perpendicular to an element array direction of the second position detection device.

12. The curvature measurement apparatus according to claim 2, wherein the laser beam emitted by the light emitting portion emits is a laser beam with a wavelength of 700 nm or less.

14. The curvature measurement apparatus according to claim 2, wherein

the first position detection device includes a first light receiving surface on which the first laser beam is incident,

a normal direction to the first light receiving surface is inclined at least at 10 degrees with respect to the optical axis of the first laser beam,

the second position detection device includes a second light receiving surface on which the second laser beam is incident, and

a normal direction to the second light receiving surface is inclined at least at 10 degrees with respect to the optical axis of the second laser beam.

16. The curvature measurement apparatus according to claim 2, further comprising a shaping portion configured to expand the first laser beam in a direction perpendicular to an element array direction of the first position detection device, and to expand the second laser beam in a direction perpendicular to an element array direction of the second position detection device.

17. A curvature measurement method, comprising the steps of:

emitting a laser beam by a light emitting portion;

separating, by a first polarization beam splitter, the laser beam emitted by the light emitting portion into a first laser beam and a second laser beam which are in different polarization directions and in different travel directions;

reflecting any one of the first and second laser beams by a reflection portion so that the first and second laser beams travel side by side to a measurement object;

transmitting, through a second polarization beam splitter, any one of the first laser beam and the second laser beam mirror-reflected from the measurement object, and reflecting the other laser beam by the second polarization beam splitter in a direction different from a travel direction of the one laser beam;

detecting, by a one-dimensional first position detection device, an incident position where the first laser beam reflected from or transmitted through the second polarization beam splitter is incident on the first position detection device; and

detecting, by a one-dimensional second position detection device, an incident position where the second laser beam transmitted through or reflected from the second polarization beam splitter is incident on the second position detection device.

18. A curvature measurement method, comprising the steps of:

emitting a laser beam by a light emitting portion;

separating, by a first polarization beam splitter, the laser beam emitted from the light emitting portion into a first laser beam and a second laser beam which are in different polarization directions and in different travel directions;

reflecting the second laser beam by a reflection portion so that the first and second laser beams travel side by side to a measurement object;

transmitting, through a second polarization beam splitter, any one of the first and second laser beams traveling toward the measurement object;

causing the first and second laser beams traveling toward the measurement object to pass through a quarter-wave plate, and causing the first and second laser beams mirror-reflected from the measurement object to pass through the quarter-wave plate;

causing a first position detection device to detect an incident position where the first laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is incident on the first position detection device; and

causing a second position detection device to detect an incident position where the second laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is incident on the second position detection device.

19. The curvature measurement method according to claim 18, wherein

in a case where the first laser beam traveling toward the measurement object is transmitted through the second polarization beam splitter,

the first laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is reflected by the second polarization beam splitter and is detected by the first position detection device, and

the second laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is reflected by the reflection portion, and is detected by the second position detection device.

20. The curvature measurement method according to claim 18, wherein

in a case where the first laser beam traveling toward the measurement object is transmitted through the second polarization beam splitter,

the first laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is reflected by the first polarization beam splitter and is detected by the first position detection device, and

the second laser beam mirror-reflected from the measurement object and coming through the quarter-wave plate is reflected by the second polarization beam splitter, and is detected by the second position detection device.