Method for measuring a high accuracy height map of a test surface

Inventors: Adriaan Tiemen Zuiderweg (Breda, NL); Johannes Anna Quaedackers (Veldhoven, NL); Harm Visscher (Tilburg, NL)

Assignee: MITUTOYO CORPORATION

G06T11/206 G01B11/245 G01B11/2441 G01B2210/52

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Quick Facts

Patent No.: US 9,881,400
App. No.: 14/808,230
Granted: Jan 30, 2018
Kind: B2

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Abstract

Method for measuring a height map of a test, including measuring a coarse height map of the test surface with a pre-map sensor provided to an optical profiler with a relatively long working distance and/or a large field of view, storing the coarse height map in a memory, subdividing the coarse height map into sections appropriate for the field of view of a high resolution optical profiler sensor provided to the optical profiler, calculating corresponding X, Y and Z positions for the optical profiler sensor with respect to the test surface, calculating a trajectory in the X, Y, Z-direction for the optical profiler sensor with respect to the test surface using the calculated X, Y, Z-positions, moving the optical profiler in the X, Y, Z-direction with respect to the test surface according to the trajectory, and measuring a high accuracy height map with the high resolution optical profiler sensor.

Claims (46)

1. A method for measuring a high accuracy height map of a test surface using a multi sensor optical profiler, the optical profiler including a low resolution pre-map sensor and a high resolution optical profiling sensor having a resolution higher than a resolution of the low resolution pre-map sensor, comprising:

measuring a coarse height map of the test surface with the low resolution pre-map sensor at at least one of a working distance longer than a working distance of the high resolution optical profiling sensor and a field of view larger than a field of view of the high resolution optical profiling sensor;

storing the coarse height map in a memory;

subdividing the coarse height map into sections as appropriate for the field of view of the high resolution optical profiling sensor provided to the optical profiler;

calculating corresponding X, Y and Z positions for the high resolution optical profiling sensor with respect to the test surface;

calculating, using the calculated X Y Z positions, a trajectory in the X Y Z direction for the high resolution optical profiling sensor with respect to the test surface;

moving the optical profiler in the X, Y, Z-direction with respect to the test surface according to the trajectory; and, measuring, with the high resolution optical profiling sensor, a high accuracy height map having a higher accuracy than the coarse height map.

2. The method according to claim 1 , wherein the low resolution pre-map sensor includes one of a confocal sensor, a triangulation focus sensor, a knife edge focus sensor, a chromatic point sensor, a confocal sensor, a points from focus sensor, a structured illumination microscopy sensor, a vertical image contrast through focus sensor, lateral image contrast through focus sensor, a tactile sensor, and a capacitive sensor.

3. The method according to claim 1 , wherein the coarse height map from the low resolution pre-map sensor is composed of one of multiple merged, overlaid or joined individual measurements from the low resolution pre-map sensor.

4. The method according to claim 1 , further comprising moving the test surface with respect to the optical profiler apparatus by actuating by X, Y and Z stages.

5. The method according to claim 1 , wherein the calculating of the trajectory in the X Y Z direction comprises randomizing the order in which the high resolution optical profiling sensor measures a height map of the sections.

6. The method according to claim 1 , wherein the calculating of the trajectory in the X Y Z direction comprises ordering the trajectory.

7. The method according to claim 1 , wherein the subdividing results in the sections one of overlapping and adjoining.

8. The method according to claim 1 , wherein the calculating of the trajectory in the X Y Z direction comprises subtracting the calibrated distance between the low resolution pre-map sensor and the high resolution optical profiling sensor from the coarse height map.

9. The method according to claim 1 , wherein the measuring the high accuracy height map comprises scanning the test surface through the focal range of the high resolution optical profiling sensor.

10. The method according to claim 1 , wherein the high resolution optical profiling sensor is one of a white light interferometry sensor, a phase-shifting interferometry sensor or a wavelength scanning interferometry sensor, a confocal sensor, a points from focus sensor, and a structured illumination microscopy sensor.

11. The method according to claim 1 , further comprising:

allowing a user to view an image created by the low resolution pre map sensor;