TOPOGRAPHICAL MEASURING DEVICE AND TOPOGRAPHICAL MEASURING METHOD

Abstract

TOPOGRAPHICAL MEASURING DEVICE AND TOPOGRAPHICAL MEASURING METHOD A topographic measuring device comprises a sample holder (1) receiving a sample (2). A first projector (3) applies a first textured light (4) to a first portion (2a) of the sample (2). A second projector (5) applies a second textured light (6) to a second portion (2b) of the sample (2) different from the first portion (2a). A first camera (7) observes the first textured light applied to the first portion (2a) to acquire first images (8). A second camera (9) observes the second textured light (6) applied to the second portion (2b) to acquire second images (10). The second textured light (6) has patterns with a second repetition pitch smaller than a first repetition pitch of the patterns of the first textured light (4).

Description

Title of the invention: TOPOGRAPHICAL MEASURING DEVICE AND TOPOGRAPHICAL MEASURING METHOD Technical field

[0001] The invention relates to a topographical measuring device and a topographical measuring method. Prior art

[0002] In many technical fields related to printed circuits, different materials are combined with particular patterns to form electrical or electronic functions. These patterns mean that the volume of a printed circuit is not homogeneous so that it deforms anisotropically depending on the temperature and over time. It is also clear that printed circuits generally have elements that protrude from a main surface. These protruding elements must have the best possible shape and dimensions. For example, the protruding elements are electrically conductive pads that will serve as an electrical contact for an electronic chip or any other electronic device. Good dimensional control of the protruding elements ensures efficient electrical contact.

[0003] It is important to be able to measure the shape and dimensions of multiple protruding elements as accurately and quickly as possible. It is also important to know the general or specific deformation of a chip or printed circuit in order to anticipate the causes of failure.

[0004] It is known to carry out a measurement of the dimensions of the protruding elements and deformation of a chip by means of an optical method. Textured light is applied to the surface of a sample. The textured light defines a plurality of repeating patterns which are applied to the surface of the sample.

[0005] Several images are acquired of the surface of the sample which is illuminated by the textured light. By analyzing the different images, it is possible to calculate the dimensions and shape of the protruding elements and / or to calculate the three-dimensional deformation of the chip.

[0006] The quality of the measurement is highly dependent on the quality of the images that have been acquired as well as the characteristics of the textured light. The textured light defines several areas having color differences, typically black areas and white areas with preferentially a transition through gray levels. The distance between two black areas or two white areas imposes the resolution of the deformation measurement. The quality of the measurement also depends on the resolution of textured light, that is, the distance between two white areas or two black areas. The resolution is limited by the technique of forming textured light as well as by physical limitations. Since the study area is small, it is not possible to have an infinite fringe density.

[0007] Logically, the quality of the measurement is a function of the optical performance of the camera, i.e. the resolution of the image acquired by the camera, which corresponds to the number of pixels per unit length. For a given sample and for a given camera, there is a compromise to be found between the measurement definition capable of being defined by the textured light and the measurement resolution of the camera. There is no point in providing textured light with a very small repetition pitch if the latter is much lower than the resolution of the camera. Conversely, a camera with a high resolution will be limited by the resolution of textured light with a coarse pitch.

[0008] In order to maintain a reasonable size and cost, it is not interesting to have a camera with a large collection surface and a low definition step. It is also counterproductive to seek textured light that is as fine as possible in order to measure coarse deformations of the sample. Depending on the type of deformation to be measured, it is necessary to adapt the characteristics of the textured light and the resolution of the camera. Subject of the invention

[0009] An object of the invention is to provide a topographical measuring device which has a better compromise between its ability to measure coarse deformation and its ability to measure fine deformation.

[0010] This result is tended to be achieved by means of a topographical measuring device comprising: - a sample holder intended to receive a sample; - a first projector intended to apply a first textured light to at least a first part of the sample; - a second projector intended to apply a second textured light to at least a second part of the sample, the second part being different from the first part; - a first camera intended to observe the first textured light applied to the first part of the sample to acquire a first series of images; - a second camera intended to observe the second textured light applied to the second part of the sample to acquire a second series of images; - a control circuit connected to the first projector, the second projector, the first camera and the second camera, the control circuit being configured so that the second textured light has patterns with a second repetition pitch smaller than a first repetition pitch of the patterns of the first light textured.

[0011] Advantageously, the second part is adjacent to the first part.

[0012] In a particular configuration, the second part at least partially covers the first part.

[0013] In an advantageous development, the first part of the sample forms a ring around the second part of the sample.

[0014] Preferably, the first projector defines an empty area devoid of patterns. The second projector illuminates the empty area without illuminating the patterns of the first textured light.

[0015] According to one embodiment, the control circuit is configured to simultaneously acquire the images of the first series of images and the second series of images.

[0016] In an advantageous development, the control circuit is connected to at least one shutter configured to alternately block a transmission of the first textured light and the second textured light towards the sample holder in the second part to avoid a superposition of the first textured light and the second textured light or the control circuit is configured to alternately emit the first textured light and the second textured light.

[0017] Preferably, the control circuit is configured to acquire at least one image of the second series of images between two images of the first series of images, in a time period.

[0018] The invention also relates to a method for topographically measuring a sample which more easily performs coarse deformation and fine deformation measurements.

[0019] This result is tended to be achieved by means of a method of topographical measurement of a sample comprising the following steps: - place a sample on a sample holder; - apply a temperature ramp to the sample; - applying a first textured light to a first portion of the sample and a second textured light to a second portion of the sample different from the first portion of the sample, the second textured light having patterns with a second repetition pitch lower than a first repetition pitch of the patterns of the first textured light; - acquire a first series of images of the first textured light applied to the first part of the sample during the temperature ramp; - acquire a second series of images of the second textured light applied to the second part of the sample during the temperature ramp; - process the first set of images and the second set of images to determine a first deformation of the first part and a second deformation of the second part during the temperature ramp.

[0020] In a preferred development, the second part is included in the first part. The first deformation is subtracted from the second deformation. Brief description of the drawings

[0021] Other advantages and characteristics will emerge more clearly from the following description of particular embodiments and implementations of the invention given as non-limiting examples and represented in the appended drawings, in which:

[0022] [Fig-1]: [Fig.l] schematically illustrates an embodiment of a device for topographic measurement according to the invention;

[0023] [Fig.2]: [Fig.2] schematically illustrates a top view of a sample subjected to two different textured lights;

[0024] [Fig.3]: [Fig.3] schematically illustrates a top view of a sample subjected to two different textured lights;

[0025] [Fig.4]: [Fig.4] schematically illustrates a top view of a sample subjected to the first textured light which is capable of covering second parts of the sample illustrated in dotted lines;

[0026] [Fig.5]: [Fig.5] schematically illustrates a top view of a sample subjected to the first textured light which defines empty zones delimiting second parts of the sample illustrated in dotted lines;

[0027] [Fig.6]: [Fig.6] schematically illustrates a top view of a sample subjected to the second textured light delimiting second parts of the sample, the first part being illustrated in dotted lines. Description of the embodiments

[0028] [Fig.l] illustrates a topographical measuring device which has a sample holder 1 intended to support a sample 2. The topographical measuring device also comprises a first projector 3 intended to apply a first textured light 4 to at least a first part 2a of the sample 2 as well as a second projector 5 intended to apply a second textured light 6 to at least a second part 2b of the sample 2. The second part 2b is different from the first part 2a.

[0029] The sample holder 1 has a first face intended to receive the sample 2. The direction Z is normal to the first face.

[0030] Each of the first textured light 4 and the second textured light 6 defines several repetitive patterns, for example several fringes. The illumination of the surface of the sample 2 is carried out by the first projector 3 and the second projector 5. The Textured light can be an image in shades of gray or shades of other colors and possibly in black and white. Textured light defines patterns that repeat with a predefined frequency and a predefined phase. Projectors are projection means that are configured to project textured light preferably in the visible range.

[0031] The textured light advantageously forms a network of fringes, for example of the moiré or “shadow moiré” type. In one embodiment, the projector directly emits a network of fringes. In an alternative embodiment, the textured light is formed by means of a mask through which the light coming from the projector passes. The mask comprises openings and opaque zones, for example in the form of a Ronchi network. It is also possible to combine these two techniques.

[0032] Predefined patterns are applied to the surface of the sample and the topography of the sample will modify the shape of the applied patterns. By analyzing the shape changes of the patterns, it is possible to calculate the three-dimensional deformation of the sample.

[0033] The topographical measuring device comprises a first camera 7 intended to observe the first textured light 4 applied to the first part 2a of the sample 2 to acquire at least a first series of images 8 as well as a second camera 9 intended to observe the second textured light 5 applied to the second part 2b of the sample 2 to acquire at least a second series of images 10. The second camera 9 is different from the first camera 7. Alternatively, the first camera 7 and the second camera 9 share the same capture sensor, but the image comes from two different paths by means of lenses and / or prisms so as to observe two different portions of the sample 2 placed on the sample holder 1.

[0034] The first camera 7 and the second camera 9 are image capture means configured to acquire series of images of the surface of the sample 2. The first camera 7 and the second camera 9 are arranged to capture the textured light applied to the surface of the sample 2. Preferably, the optical axis of the first camera 7 and of the second camera 9 is parallel to the Z direction normal to the surface of the sample holder 1 or has a small offset relative to the Z direction.

[0035] Each camera acquires a series of images. The images of each series are compared with each other or with a reference, to observe the deformations of the textured lights and to deduce the deformations of sample 2.

[0036] The images are sent to a calculation circuit A configured to calculate the deformations between the images and to calculate the three-dimensional deformation of sample 2.

[0037] The topographical measuring device comprises a control circuit 16 connected to the first projector 3, to the second projector 5, to the first camera 7 and to the second camera 9. The control circuit 16 is configured so that the second textured light 6 has patterns with a second repetition pitch smaller than a first repetition pitch of the patterns of the first textured light 4. The second textured light 6 having patterns with a second repetition pitch smaller than a first repetition pitch of the patterns of the first textured light 4, the second textured light 6 makes it possible to measure finer deformations than the first textured light 4.

[0038] During the deformation of the sample 2, the first camera 7 will acquire a series of images of the first part 2a of the sample 2 on which the first textured light 4 is applied with the first repetition step. To measure the relevant information, the resolution of the first camera 7 is adapted to the surface of the first part 2a and to the quantity of information provided by the first textured light 4. The larger the surface of the first part 2a, the greater the quantity of information to be processed. The larger the repetition step of the first textured light 4, the greater the quantity of information to be processed. The performance of the first camera 7 defines the pair: surface of the first part / repetition step of the first textured light 4. It is advantageous for the first camera 7 to have an adjustable magnification so as to adjust the performance of the measurement to the needs.Preferably, the first projector 3 is provided with a magnification means, for example a plurality of movable lenses, which is configured to increase or reduce the magnification of the repetition pitch of the first textured light 4. Preferably, the repetition pitch is adapted to the extent of the surface of the first part 2a and / or to the desired measurement resolution. Alternatively, the first projector 3 is capable of delivering different first textured lights 4 with different repetition pitches.

[0039] During the deformation of the sample 2, the second camera 9 will acquire a series of images of the second part 2b of the sample 2 on which the second textured light 6 is applied with the second repetition pitch. The resolution of the second camera 9 is adapted to the definition provided by the second textured light 6 and to the size of the second part 2b to measure the relevant information. It is advantageous for the second camera 9 to have an adjustable magnification so as to adjust the performance of the measurement to the needs. Preferably, the second projector 5 is provided with a magnification means, for example a plurality of movable lenses, which is configured to increase or reduce the magnification of the repetition pitch of the second textured light 6. Preferably, the repetition pitch is adapted to the extent of the surface of the second part 2b and / or to the desired measurement resolution. Alternatively, the second projector 5 is capable of delivering different first textured lights 4 with different repetition steps.

[0040] The second repetition step being smaller than the first repetition step, it is advantageous for the resolution of the second camera 9 to be greater than the resolution of the first camera 7. Preferably, the magnification of the second camera 9 is greater than the magnification of the first camera 7, during the deformation measurement, if the sensors of the two cameras have the same definition. For example, the first camera 7 and the second camera 9 are identical and the adaptation of the resolution of the images taken by the two cameras is defined by the magnification of the lens arranged upstream of the sensor along the optical path.

[0041] The topographic measuring device comprises heating means 12 and / or cooling means 13 which are connected to the control circuit 16. The heating means 12 and / or cooling means 13 are arranged so as to heat or cool the sample 2 so that the sample 2 follows a predefined temperature profile. Preferably, the heating means 12 comprise heating by infrared radiation. Advantageously, the cooling means 13 comprise the application of a fluid which circulates in the sample holder 1 or in direct contact with the sample holder 1. Depending on requirements, the fluid may be a gas or a liquid. The nature of the fluid depends on the minimum temperature of the sample holder 1 which is desired to be achieved.

[0042] The control circuit 16 applies a temperature ramp to the sample 2. During the temperature ramp, the temperature value of the sample 2 changes and the sample 2 deforms. During the temperature ramp, the first textured light 4 is applied to the first portion 2a of the sample 2 and the second textured light 6 is applied to the second portion 2b of the sample 2. During the temperature ramp, the first series of images 8 and the second series of images 10 are acquired. The images of the first series of images 8 are used, for example, to measure the deformation of the first portion 2a during the temperature ramp. The images of the second series of images 10 are used, for example, to measure the deformation of the second portion 2b during the temperature ramp.

[0043] During the same temperature ramp, the second series of images 10 makes it possible to carry out a finer measurement of the deformation in the second part 2b than the measurement of deformation in the first part 2a which is carried out by the first series of images 8. The two series of images are acquired during the same temperature ramp which makes it possible to better characterize the behavior of the sample 2 in comparison with two measurements carried out in two successive temperature ramps because this avoids an aging effect of the sample 2.

[0044] It is particularly advantageous to use the deformation data acquired for the first part 2a in order to calculate more precise deformation data for the second part 2b. In order for the deformation data relating to the first part 2a to be the most relevant for studying the deformation of the second part 2b, it is preferable for the second part 2b to be as close as possible to the first part 2a. Advantageously, the second part 2b is adjacent to the first part 2a, that is to say that the first part 2a has an interface with the second part 2b.

[0045] Advantageously, at least a portion of the second part 2b is included in the first part 2a. The first part 2a can be considered as a non-convex and non-crossing polygon, for example a rectangle whose intersection with a smaller rectangle has been removed. The second part 2b encroaches inside the first part 2a. Depending on the configurations, the portion taken by the second part 2b is measured or not by means of the first textured light 4 and the first camera 7. Preferably, at least 50% of the surface of the second part 2b is included in the surface of the first part 2a. More advantageously, the second part 2b is included in the first part 2a, that is to say that the first part 2a forms a ring around the second part 2b.

[0046] The application of the first textured light 4 and the application of the second textured light 6 on the first part 2a and on the second part 2b can be carried out in different ways. In one case, the first textured light 4 and the second textured light 6 are applied simultaneously during the temperature ramp. This embodiment is advantageous when the first camera 7 and the second camera 9 respectively carry out the acquisition of the first series of images 8 and the second series of images 10 simultaneously.

[0047] When the first part 2a and the second part 2b are slightly offset or have a single side as an interface, it is possible to apply the two textured lights simply. When the first part 2a and the second part 2b overlap partially or completely, it is important that the first textured light 4 does not overlap with the second textured light 6. The first textured light 4 will define an empty area, that is to say an area without a pattern which is preferably an unlit area. This empty area corresponds in whole or in part to the second part 2b.

[0048] The empty area may come from a part of the lighting device of the first projector 3 which is not activated or from a shutter 11 arranged between the first projector 3 and the sample 2 along the optical path. The empty area preferably corresponds as faithfully as possible to the second part 2b. The second textured light 6 is applied in the empty area delimited at least in part by the first textured light 4. A shutter 11 may also be present along the optical path of the second projector 5 to form an empty area, i.e. without illumination by the second projector 5. Activation and extinction of the shutter 11 make it possible to modify the extent of the illuminated area. Preferably, the shutter 11 associated with the first projector 3 operates independently of the shutter 11 of the second projector 5.

[0049] It is advantageous to use an empty area which is an unlit area in order to be able to benefit from greater dynamics in the definition of the patterns and in particular when the patterns are represented in black and white or with gray levels. Alternatively, the first textured light 4 and the second textured light 6 use different wavelengths for example to define different colors and are projected simultaneously over the entirety of their respective area. The first camera 7 or the control circuit 16 selects the first textured light 4 by colorimetric analysis, or preferably by a first optical filter 14. The second camera 9 selects the second textured light 6 by colorimetric analysis, or preferably by a second optical filter 15. [Fig.2] illustrates an embodiment where the first part 2a completely surrounds the second part 2b and the two textured lights are applied simultaneously, the second part 2b being arranged within a ring defined by the first part 2a. [Fig.3] illustrates an embodiment where the first part 2a and the second part 2b are adjacent and offset from each other. The interface is in the form of a straight line.

[0050] In a preferred embodiment, the control circuit 16 is configured to simultaneously acquire the images of the first series of images 8 and the second series of images 10 in a period of time. The first textured light 4 is applied with a first wavelength and the second textured light 6 is applied with a second wavelength different from the first wavelength. The control circuit 16 separates the first textured light 4 and the second textured light 6 by colorimetric analysis or the first camera 7 and the second camera 9 are provided with optical filters.

[0051] In an alternative embodiment illustrated in Figures 4, 5 and 6, the first textured light 4 is applied alternately with the second textured light 6 during the temperature ramp. This embodiment is advantageous when the second part 2b is included at least in part in the first part 2a.

[0052] The first projector 3 and the second projector 5 can respectively apply the first textured light 4 and the second textured light 6 alternately to the first part 2 and the second part 2b. Figures 4 and 5 illustrate the application of the first textured light 4, the second part 2b being illustrated in dotted line. [Fig.6] illustrates the application of the second textured light 6, the first part 2a being illustrated in dotted line.

[0053] Alternatively, at least one shutter 11 is connected to the control circuit 16 and is mounted to move to alternately shutter the first textured light 4 and the second textured light 6 and thus alternately illuminate the sample 2. The use of a shutter 11 is particularly advantageous because it can be moved quickly to block at least part of the first textured light 4. This avoids regularly switching on and off the first projector 3 and / or the second projector 5. The control circuit 16 can be configured so that the same portion of the sample 2 is not illuminated simultaneously by the first textured light 4 and the second textured light 6.

[0054] The alternative application of the first textured light 4 and the second textured light 6 when the first part 2a and the second part 2b overlap and more preferably completely cover each other makes it possible to measure two different deformations on the second part 2b.

[0055] The first series of images 8 makes it possible to measure the deformation of the first part 2a. The second series of images 10 makes it possible to measure the deformation of the second part 2b. When the second part 2b and the first part 2a overlap, it is advantageous to subtract the overall deformation of the first part 2a from what is measured for the second part 2b in order to determine the specific deformation of the second part 2b. When the first series of images corresponds to a measurement area which is larger than the second series of images and the first area completely surrounds the second area or overlaps the second area over at least 50% of its surface, it is particularly advantageous to have a first series of images 8 which provides a lower resolution than the second series of images 10, for example at least 20% lower in order to limit the amount of information to be processed.

[0056] As an alternative to subtracting the deformations, it is possible to compare the deformation of the second part 2b with the deformation of the first part 2a. If the difference between the deformations is less than a threshold value, the layer(s) of the second part 2b are compatible with the layer(s) of the first part 2a. For example, the second part 2b corresponds to all or part of a component arranged on a support. The first part 2a extends over the support. Comparing the deformations makes it possible to detect whether the deformation of the component is compatible with the deformation of the support. Alternatively, the second part 2b extends into a hole in the support in order to detect whether the hole formed in the support modifies the deformation of the support. For example, the hole formed in the support causes two different stacks of layers to be compared.

[0057] In another alternative, the first series of images 8 is analyzed and calculated an interpolated topography on the second part 2b from the measurement of the first part 2a. Then, the interpolated deformation measurement of the first part 2a is subtracted from the deformation measurement of the second part 2b, to analyze only the local deformations in the second part 2b. When the second part 2b has a stacking different from the first part 2a, the interpolation makes it possible to estimate the deformation component corresponding to the stacking of the first part 2a with respect to the deformation calculated from the second series of images 10.

[0058] Preferably, the second part 2b is included in the first part 2a. The first deformation is subtracted from the second deformation or the first deformation and the second deformation are compared or an interpolated topography of the second part 2b which was calculated from the first deformation is subtracted from the first deformation to calculate the local deformations of the second part 2b.

[0059] The control circuit 16 comprises one or more processors, one or more memories intended to store information. The control circuit 16 can be included in a computer.

[0060] It is particularly advantageous for the images of the first series of images 8 to be acquired simultaneously with the images of the second series of images 10, i.e. at the same time or almost at the same time so that two images are representative of the same state of deformation. The use of two projectors and two cameras allows for greater measurement speed than a single projector applying two different sets of textured lights and / or a camera making two different acquisitions. By adapting the resolution of the image taken by the camera to the resolution of the textured light pattern provided by the projector, the content of relevant data delivered by the camera is improved. This avoids providing data that is not precise enough because the camera is not efficient enough with regard to textured light and avoids saturating the control circuit 16 with useless data because the textured light has too coarse a pitch.

[0061] Preferably, the two projectors are mounted to be movable relative to the sample holder 1. In one embodiment, the two projectors are mounted to be movable in directions X and Y and the sample holder 1 is mounted to be stationary in these two directions. In another embodiment, the two projectors are mounted to be stationary in directions X and Y and the sample holder 1 is mounted to be movable in these two directions. In a final embodiment, the two projectors are mounted to be movable in directions X and Y and the sample holder 1 is also mounted to be movable in these two directions. The two projectors can be mounted to be movable independently of each other in directions X and / or Y. The directions X and Y are perpendicular to each other and perpendicular to the Z direction.

[0062] It is also possible to provide that the first camera 7 and / or the second camera 9 are mounted to move relative to the sample holder 1 in the directions X and Y.

[0063] Alternatively or additionally, the control circuit 16 is also configured to move the first part 2a along the sample 2 during the deformation to calculate the deformation of a surface greater than at least twice the surface of the first part 2a, preferably to calculate the deformation of a surface greater than 80% of the surface of the sample 2. More preferably, the control circuit 16 is configured so that the first projector 3 and the second projector 5 apply a first textured light 4 and a second textured light 6 which have the same repetition pitch. It is advantageous for the control circuit to move the two projectors and the two cameras so that the first part 2a and the second part 2b move independently of each other in order to characterize at least 80% of the surface of the sample 2.By using two separate pairs of projectors and cameras, it is possible to measure the surface of sample 2 twice as fast.

Claims

Claims

1. Topographical measuring device comprising: - a sample holder (1) intended to receive a sample (2); - a first projector (3) intended to apply a first textured light (4) to at least a first part (2a) of the sample (2); - a second projector (5) intended to apply a second textured light (6) to at least a second part (2b) of the sample (2), the second part (2b) being different from the first part (2a); - a first camera (7) intended to observe the first textured light (4) applied to the first part (2a) of the sample (2) to acquire a first series of images (8); - a second camera (9) intended to observe the second textured light (6) applied to the second part (2b) of the sample (2) to acquire a second series of images (10);- a control circuit (16) connected to the first projector (3), to the second projector (5), to the first camera (7) and to the second camera (9), the control circuit (16) being configured so that the second textured light (6) has patterns with a second repetition pitch smaller than a first repetition pitch of the patterns of the first textured light (4).;

2. A topographical measuring device according to claim 1 wherein the second part (2b) is adjacent to the first part (2a).

3. Topographic measuring device according to claim 2 wherein the second part (2b) at least partially covers the first part (2a).

4. A topographic measuring device according to claim 3 wherein the first portion (2a) of the sample (2) forms a ring around the second portion (2b) of the sample (2).

5. A topographical measuring device according to claim 3 or 4 wherein the first projector (3) defines an empty area devoid of patterns and wherein the second projector (5) illuminates the empty area without illuminating the patterns of the first textured light.

6. A topographical measuring device according to any one of claims 1 to 5 wherein the control circuit (16) is configured to simultaneously acquire the images of the first series of images (8) and the second series of images (10) within a period of time.

7. A topographical measuring device according to claim 6 wherein the first textured light (4) is applied with a first wavelength and the second textured light (6) is applied with a second wavelength different from the first wavelength and wherein the control circuit (16) separates the first textured light (4) and the second textured light (6) by colorimetric analysis or the first camera (7) and the second camera (9) are provided with optical filters.

8. A topographical measuring device according to claim 3 or 4 wherein the control circuit (16) is connected to at least one shutter (11) configured to alternately block a transmission of the first textured light (4) and the second textured light (6) towards the sample holder (1) in the second part (2b) to avoid a superposition of the first textured light (4) and the second textured light (6) or wherein the control circuit (16) is configured to alternately emit the first textured light (4) and the second textured light (6).

9. A topographical measuring device according to claim 8 wherein the control circuit (16) is configured to acquire at least one image of the second series of images (10) between two images of the first series of images (8) in a period of time.

10. A method for topographical measurement of a sample (2) comprising the following steps: - arranging a sample (2) on a sample holder (1); - applying a temperature ramp to the sample (2); - applying a first textured light (4) to a first portion (2a) of the sample (2) and a second textured light (6) to a second portion (2b) of the sample (2) different from the first portion (2a) of the sample (2), the second textured light (6) having patterns with a second repetition pitch smaller than a first repetition pitch of the patterns of the first textured light (4); - acquiring a first series of images (8) of the first textured light (4) applied to the first portion (2a) of the sample (2) during the temperature ramp; - acquiring a second series of images (10) of the second textured light (6) applied to the second part (2b) of the sample (2) during the temperature ramp;- processing the first series of images (8) and the second series of images (10) to determine a first deformation of the first part; (2a) and a second deformation of the second part (2b) during the temperature ramp.

11. A method of topographical measurement of a sample (2) according to claim 10 wherein the second part (2b) is included in the first part (2a) and wherein the first deformation is subtracted from the second deformation or wherein the first deformation and the second deformation are compared or wherein an interpolated topography of the second part (2b) which has been calculated from the first deformation is subtracted from the first deformation to calculate the local deformations of the second part (2b).

Images