FR3099569A1 - device for inspecting a surface of an object - Google Patents

Abstract

Device for inspecting (1) a surface (S) of an object, the device comprising a polychromatic light source (20) for projecting an inspection beam onto the surface (S); a confocal mask (6a, 6b) intercepting the inspection beam and a beam reflected from the surface, having a plurality of chromatic filtering apertures; a chromatic system (3) spatially spreading the focus of the inspection beam along focusing planes along an optical axis (AO) in a depth of field, intercepting the reflected beam to project it onto a detection plane (P ) combined focusing planes; a movable support (4) for positioning the surface (S) in the depth of field; a timed integration image sensor (5) synchronized with the displacement of the surface, the image sensor (5) comprising a matrix of photodetectors arranged in the detection plane (P), the chromatic filtering openings of the illuminating confocal mask part of the photodetectors. Fig. 1

Description

device for inspecting a surface of an object

The present invention relates to a device for inspecting a surface of an object. A device according to the invention allows the inspection of the surface of the object when the latter comprises strong variations in height and allows the generation at high speeds of intensity images representative of the reflectivity of this surface with a depth wide field of view and high lateral resolution. In general, the invention relates to the field of imaging for the inspection and control of objects, such as substrates for the semiconductor industry or integrated optics (semiconductor wafers or substrates in all forms, in progress or at the end of manufacture of semiconductor devices), or other objects in the fields of mechanics or manufacturing industry for example (micro-mechanisms, parts or assembly of watchmaking, assembled systems).

TECHNOLOGICAL BACKGROUND OF THE INVENTION

In the field of the semiconductor industry, the increase in the production rates of semiconductor device wafers and the reduction in the size of the patterns create a growing need for high-speed imaging inspection. The methods for imaging these wafers must therefore allow the rapid localization of defects, structures and patterns over the entire surface of the wafers. Furthermore, due to the curvature of the wafers in particular, or due to the height of the structures to be imaged (edges of the wafer, etc.), it is necessary to be able to produce sharp images in an area of extended depth of field. In other fields, such as those of micromechanics or watchmaking, the objects to be inspected may have significant relief or differences in height, also requiring extended depths of field.

Optical imaging systems such as conventional microscopes are known. These systems are generally limited in depth of field: the optical diffraction limit makes it very difficult to have both high magnification and a great depth of field. This is particularly penalizing when inspecting distant surfaces or structures with significant heights or depths. This problem is generally solved by keeping the lens at the desired distance from the measured surface, by an autofocus type system. This translates into lower travel speeds and more complex systems, or even the need to perform multiple passes to acquire images.

US 8,654,324 implements a method to increase the depth of field by exploiting the chromatic dispersion of a chromatic lens. Light transmitted through a slit is projected onto an object through a chromatic lens. The light reflected by the inspected surface is returned to the chromatic objective then transmitted through a slit placed in front of a linear detector. The chromatic objective used in this configuration increases the measurement depth of field by exploiting the fact that different wavelengths are focused at different distances on the object. However, this system is not suitable for forming two-dimensional intensity images with high lateral resolution. This is due to its slit configuration which does not meet the criteria of confocal detection in one dimension and thus generates crosstalk or cross-talk between measurement channels.

Document US 9,739,600 B1 describes a system allowing the location of patterns in two dimensions with an extended depth of field obtained by a chromatic lens. The profile or the distance of the identified structures can be measured by the same instrument while respecting the criteria of confocal detection, with a minimum of cross-talk between measurement channels. However, the system acquisition speed is directly limited by the amount of light collected by the photodetector and especially by the number of measurement channels that can be implemented.

More specifically, the inspection rates depend on the optimization of the filling factor of the measurement points on the inspected wafers and defining the density of points measured at each instant. The fill factor is defined as the ratio between the diameter of the measurement points (diameter of the beam of light projected on the wafer at the point of focus) and the separation between two measurement points. Thus, the use of optical fibers or integrated optical circuits poses a physical limitation on the possibility of bringing the measurement channels closer together.

One of the objectives of the invention is to propose a device for rapidly imaging a surface of an object over an extended depth of field.

Another objective of the invention is to propose such a device allowing a high density of measurement points (high spatial resolution) while minimizing the coupling of light (cross-talk) between the detection channels.

Another objective of the invention is to allow localization and inspection of structures and patterns of a surface of an object such as a semiconductor substrate.

BRIEF DESCRIPTION OF THE INVENTION

With a view to achieving one of these aims, the invention proposes a device for inspecting a surface of an object, the device comprising:

- at least one polychromatic light source to project an inspection beam onto the surface;

- at least one confocal mask intercepting the inspection beam and a beam reflected by the surface, the confocal mask having a plurality of chromatic filtering apertures;

- a chromatic system spatially spreading the focusing of the inspection beam according to the wavelengths present, according to focusing planes along an optical axis in a depth of field, and intercepting the beam reflected by the surface to project it onto a conjugate detection plane of the focusing planes;

- a mobile support for receiving the object and positioning the surface in the depth of field of the chromatic system, the support being able to be controlled to move the surface relative to the chromatic system at least along one direction of inspection;

- a timed integration image sensor synchronized with the movement of the surface in the direction of inspection, the image sensor comprising a matrix of photodetectors arranged in the detection plane, the chromatic filtering openings of the confocal mask illuminating a part photodetectors.

According to other advantageous and non-limiting characteristics of the invention, taken alone or according to any technically feasible combination:

• the chromatic filtering openings are arranged on the confocal mask to illuminate a plurality of photodetectors arranged on a column of the matrix corresponding to a plurality of measurement points arranged along the direction of inspection;
• the chromatic filtering apertures are distributed in a complementary manner over at least two rows of the confocal mask to illuminate a plurality of photodetectors corresponding to a plurality of measurement points arranged along at least two rows arranged in a direction perpendicular to the direction of inspection;
• the confocal mask comprises a plurality of groups of at least two lines comprising chromatic filtering openings distributed in a complementary manner over said at least two lines;
• the device comprises an illumination confocal mask placed in the inspection beam and a detection confocal mask placed in the reflected beam, the lighting confocal mask and the detection confocal mask being respectively placed in a conjugate plane of the planes of focusing on the chromatic system;
• the confocal detection mask is made by depositing at least one material on the surface of the image sensor;
• the inspection device comprises a single confocal mask, arranged in a jointly conjugate plane of the detection plane and the focusing planes vis-à-vis the chromatic system;
• the polychromatic light source comprises a halogen lamp or a strip of light-emitting diodes, associated with a diffusion device to homogenize the intensity of the inspection beam;
• the color system includes a color lens;
• the chromatic lens comprises a lens or a combination of lenses, at least one diffraction lens and/or at least one metallens;
• the color system includes a separator element;
• the separating element is a separating cube or a semi-reflecting blade;
• the photodetectors are equipped with a color filter;
• the chromatic filtering apertures are arranged to each illuminate a plurality of photodetectors fitted with different color filters.

Other characteristics and advantages of the invention will emerge from the detailed description of the invention which will follow with reference to the appended figures in which:

FIG. 1 represents an inspection device according to a first embodiment of the invention;

FIG. 2 represents a block diagram of the confocal chromatic operation implemented by the device of FIG. 1;

FIG. 3 represents a front view of a detection mask illuminated by a reflected beam;

FIG. 4 represents an aperture arrangement on a confocal mask in alignment with a photodetection matrix;

FIG. 5 represents two inspection fields on the surface of a surface to be inspected.

For the sake of simplifying the description to come, the same references are used for identical elements or providing the same function in the state of the art or in the various exposed modes of implementation of the device.

FIG. 1 represents a first embodiment of an inspection device according to the present invention.

In general, the inspection device 1 projects an inspection light beam onto a surface S of an inspected object. The beam is reflected on this surface S to project onto a detection plane P of an image sensor 5.

The inspected object, such as a semiconductor substrate, is placed on a mobile support 4 of the inspection device 1, for example a table whose movement can be controlled. The mobile support 4 makes it possible to move the surface along at least one inspection direction I under the inspection beam.

The inspection device 1 comprises a lighting system 2 comprising a polychromatic light source 20 to form the inspection beam. The source 20 therefore emits several wavelengths which can for example be included in the visible spectrum, in an interval of wavelengths included between 380 nm to 700 nm, or in the infrared beyond 700 nm.

In general, the wavelengths making up the emission spectrum of the source 20 are chosen according to the nature of the object inspected and the layers which are likely to cover it. The wavelengths of the polychromatic source 20 will be chosen so that the inspection beam is reflected by the surface S of the object to be inspected. In addition, when a covering layer is present, it is possible to choose the wavelengths of the polychromatic source 20 so that they are included in the transparency spectrum of this covering layer.

By way of example, the polychromatic light source 20 can be formed by a halogen lamp or a strip of light-emitting diodes.

It is generally sought to form an inspection beam of large transverse dimension so as to illuminate a large portion of the inspected surface S, referred to as the "inspection field" in the remainder of this description. In an application in the semiconductor field, the inspection field can have a dimension between a few hundred microns and a few millimeters on a side. To this end, it is possible to provide, as is the case in the mode of implementation represented in FIG. 1, a diffusion device 21 to homogenize the intensity of the inspection light beam produced by the lighting system 2. The diffusion device 21 can for example be made of frosted glass or of an optical guide element ensuring a mixture of the modes of propagation of the radiation produced by the polychromatic source 20 so as to make the intensity of the beam of inspection.

It is also possible to provide optical fibers 22 or any other form of guide for light radiation, to conduct the light beam produced by the source 20 to the injection zone of the inspection beam in the device 1, here occupied by the diffusion device 21.

Of course, the lighting system 20 is not limited to that described for this mode of implementation. One can for example consider that it is composed of a supercontinuum polychromatic light source whose radiation is guided by at least one optical guide as far as the injection zone.

Continuing the description of FIG. 1, the inspection device 1 also comprises a chromatic system 3 placed on the optical path of the inspection beam and of the reflected beam. The chromatic system 3 generates a chromatic dispersion of the light which passes through it and thus spatially spreads the focusing of the polychromatic inspection beam, according to the wavelengths present, according to focusing planes distributed along an optical axis AO in a depth of field of the color system 3 extended compared to the depth of field obtained for an individual wavelength.

To this end, the chromatic system 3 comprises a chromatic objective 3a leading to focusing the different wavelengths of the inspection beam, over its entire transverse extent, at different distances from the objective. The chromatic objective 3 can be produced in multiple ways, for example by means of a lens or a combination of lenses. These lenses can intercept the entire transverse extent of the inspection beam, or be respectively dedicated to portions of this beam constituting measurement channels. They can also be diffraction lenses or holographic devices. They can also be metallenses, i.e. reflective or transmissive optical elements with structured reflection or transmission surfaces. The patterns constituting this surface structuring have smaller dimensions than the wavelengths of the inspection light beam and affect the phase of the radiation of this beam and therefore its shape and its propagation. The surface patterns of the optical elements can be produced by known methods of photolithography and etching.

Whatever the nature of the chromatic objective 3a, the latter is chosen to present a significant chromatic aberration, leading to the spatial spread of the inspection beam, according to the wavelengths which compose it, according to focal planes arranged in the depth of field of the chromatic system 3. This depth of field can for example extend over a distance of 100 to 200 microns.

During a measurement, the surface S of the inspected object is placed in the depth of field of the chromatic system 3. For this purpose, provision can be made for the mobile support 4 to be able to adjust the position of the surface S by moving the inspected object. along the direction of the axis AO of the chromatic system 3, so as to maintain the surface S of the object in the depth of field. This characteristic is particularly advantageous when the surface S has significant reliefs in elevation or in depression.

Consequently, and advantageously, the mobile support 4 may consist of a table provided with means that can control its movement in a plane perpendicular to the inspection beam in order to move the surface in the direction of inspection I, and complementary means ensuring a displacement in a direction perpendicular to this plane in order to maintain the surface S in the depth of field of the chromatic system 3. However, insofar as the depth of field of the chromatic system 3 is extended, the constraints for maintaining there surface S are relaxed with respect to an achromatic system.

The displacement in space of the surface S during a measurement sequence can be controlled by an electronic control unit 7. This can also collect the trajectory carried out during the measurement sequence in order to be able to reconstitute a faithful image of the inspected surface S.

Continuing the description of the mode of implementation represented in FIG. 1, the chromatic system 3 is also provided with a separating element 3b, for example a separating cube or a reflecting plate, to intercept the beam reflected by the surface S and the project onto a detection plane P of an image sensor 5. The splitter element 3b is arranged on the optical path of the reflected beam, downstream of the chromatic optics 3a, so that the reflected beam passes through this lens 3a before projecting onto the detection plane P.

Other optical parts of the chromatic system 3 can be placed on the optical path between the separator element 3b and the detection plane of the image sensor 5, but in any case the detection plane P is arranged in a plane conjugate, vis-à-vis the chromatic system 3, of the focal planes.

According to the invention, the image sensor 5 is a time-delayed integration image sensor (referred to as “image sensor” in the rest of this presentation for simplicity). The detailed operation of such a sensor is for example described in the document EP2088763. It comprises a matrix of photodetectors arranged in a plurality of rows and columns. The charges generated by the photodetectors are moved from one line to another, along a column direction synchronously with the movement of the imaged object. The last line of the matrix is moved through a shift register, or any other form of electronic component that allows the charges to be extracted from this line, in order to constitute an image line of the object.

In the inspection device 1, the matrix of photodetectors of the image sensor 5 is arranged in the detection plane P onto which the reflected beam is projected. In other words, the image sensor 5 is placed in the inspection device 1 to image the inspection field. Such a matrix can have a very large number of rows and columns, for example more than 10,000 columns and several hundred rows.

The image sensor 5 is connected to the electronic control unit 7 in order to synchronize it with the movement of the surface S along the direction of inspection I, and to repeatedly recover the lines of charges extracted from the matrix of photodetectors at the end of columns. In this configuration, and in the absence of any masking, a point on the surface S which moves along the inspection direction I is imaged successively on the photodetectors of a column of the matrix, that is to say on successive rows of the column. Simultaneously, the electrical charge generated by a photodetector is moved synchronously from one line to another, along a column direction, so that the charge accumulated at the end of this scan, at the end of the column, is representative of the light reflected by the point of the surface S throughout the duration of its displacement, in the conjugate plane of the image sensor 5, along the corresponding column of the sensor according to the direction of inspection I.

The inspection device represented in FIG. 1 also comprises two confocal masks 6a, 6b arranged in conjugate planes of the surface S of the object with respect to the chromatic system 3, and respectively placed in the optical path of the beam inspection and the reflected beam.

A first confocal lighting mask 6a is here arranged on the diffusion device 21. The mask has a plurality of lighting apertures. These openings can be crossed by the inspection beam from the lighting system, and the confocal lighting mask blocks the beam outside these openings. The inspection beam therefore consists of a plurality of lighting paths defined by the lighting apertures, projecting onto the surface S at the level of a plurality of measurement points distributed in the inspection field of the device 1, according to focal planes according to the wavelengths in the depth of field of the chromatic system 3.

A second confocal detection mask 6b is here arranged on the detection plane of the image sensor 5. Similar to the first lighting confocal mask 6a, the confocal detection mask 6b comprises a plurality of chromatic filtering apertures (or confocal chromatic), combined with the lighting apertures of the confocal lighting mask 6a. More precisely, the lighting apertures and the chromatic filtering apertures are conjugated from the same measurement points by the chromatic system 3.

The confocal detection mask 6b and the image sensor 5 are arranged relative to each other so that the chromatic filtering openings of the confocal mask 6b are respectively placed opposite a photodetector or a group of photodetectors and illuminate part of the photodetectors of the array.

For this, the confocal detection mask 6b can be plated, glued, or produced directly on the surface of the image sensor 5. It can in particular be produced by selective deposits of layers of dielectric or metallic materials on the surface of the sensor 5 .

The confocal detection mask 6b can also be made in the form of an element distinct from the sensor 5, positioned in a conjugate optical plane of the sensor by a lens or an imaging system.

In the inspection device 1 thus configured, the illumination paths of the inspection beam pass through the chromatic objective 3a. The beam is focused, according to the different wavelengths which constitute it, in focusing planes distributed over the very wide depth of field by the effect of the chromatic objective 3a. The radiation from each illumination channel is reflected by the inspected surface S, arranged in the depth of field, at the measurement points, again passes through the chromatic objective 3a, and is projected onto the confocal detection mask 6b by the intermediary of the separating element 3b.

There is thus shown in FIG. 2 a block diagram of the confocal chromatic operation implemented by the device of FIG. 1. In this figure, the lighting mask 6a has a lighting aperture defining an inspection beam comprising here a single lighting channel. By the effect of the chromatic lens 3a arranged on its optical path, the inspection beam is focused, depending on the optical wavelengths present, over an extended depth of field. In Figure 2, there is shown a first wavelength λ ₀ of the beam which is focused in a focusing plane Pf0 and a second wavelength λ ₁ of the beam which is focused on a second focusing plane Pf1, although distinct from the foreground.

The surface S to be inspected has been placed at the level of the first focusing plane Pf0, so that the illumination aperture of the illumination mask is imaged there for the first wavelength. The light at the first wavelength λ ₀ coming from the illumination aperture is therefore reflected on the surface S to be focused on the detection plane P of the image sensor 5, in the chromatic filtering aperture of the detection mask 6b. Thus, this light at the first wavelength λ ₀ reaches in all its intensity or almost the detection plane P through the opening of the mask.

On the contrary, the light at the second wavelength λ ₁ is not perfectly focused on the first focusing plane Pf0 in which the surface S resides. Consequently, this light is diffusely reflected, up to the mask of detection 6b which largely blocks it, so that little of its intensity reaches the detection plane P.

There is shown in Figure 3, a front view of the detection mask 6b, which here has 12 chromatic filtering apertures O arranged in 4 columns and 3 rows. The mask 6b is illuminated by the reflected beam in an assembly similar to that shown in FIG. 2. Also shown in FIG. 3 is the outline of the luminous halo H corresponding to the projection onto the mask of radiation at wavelengths reflected outside their focal planes on the inspected surface S.

To limit the phenomenon of coupling between different detection paths, it is important that the openings of the masks 6a, 6b are sufficiently distant from each other, so that the diffuse halo associated with an opening does not cover with too much intensity a nearby opening.

For example, the centers of two adjacent openings on the lighting mask 6a or on the detection mask 6b can be separated by a distance greater than twice the dimension of these openings (their diameters if these openings are circular).

However, the fact of moving the openings of the masks 6a, 6b away from each other leads to a reduction in the filling factor of the measurement points in the inspection field. As noted in the introduction, a reduction in the fill factor affects the inspection rate and the density of the measurement points.

To solve this problem, the openings of the illumination and detection masks are cleverly arranged vis-à-vis the photodetectors of the image sensor 5.

A part of the photodetector matrix has thus been represented in FIG. 4 in the form of a grid G. Each box of the grid symbolizes a photodetector or a group of photodetectors. The part of the matrix shown is made up of 5 columns (referenced C1 to C5) and 5 rows (referenced L1 to L5). The openings of the masks 6a, 6b are represented by circles, arranged here in alignment with the photodetectors of the camera. These openings are capable of passing the reflected beam which is then projected onto the exposed photodetectors to be measured by the image sensor 5. It is noted that these are indifferently the openings of the lighting mask 6a or of the detection 6b, these two masks being optically conjugated to each other when the photodetectors are exposed.

In this arrangement, the chromatic filtering openings are arranged on the confocal mask (6a, 6b) to respectively illuminate a plurality of photodetectors, or a plurality of groups of photodetectors, arranged on a column (C1-C5) of the matrix. The image sensor 5 is synchronized with the movement of the surface to be inspected so that the plurality of photodetectors of a column under the openings is in correspondence with a plurality of measurement points arranged along the direction of inspection (I) . When the surface S is moved along the inspection direction I, the photodetectors of the column under the openings of the mask are successively exposed to the light coming from a measurement point. At the end of the column, a charge is recovered corresponding to the quantity of light reflected by the measurement point during an extended exposure time, corresponding to the exposure time of each photodetector multiplied by the number of openings in the column. It is thus possible to produce a high-intensity image of the inspected surface and/or to increase the inspection rate.

In this arrangement also, the chromatic filtering openings are distributed over the confocal mask 6b in a complementary manner over at least two lines, that is to say for example that for a given column, if a line does not include an opening chromatic filtering, another line includes one. In particular, such a complementary distribution makes it possible to ensure that, for a group of lines which each include a chromatic filtering opening, for a sub-part of the columns, each column includes the same number of chromatic filtering openings (for example a) for the row group. In this way, a plurality of photodetectors are also distributed in a complementary manner over at least two rows of the matrix. In the example of figure 4, the photodetectors of the lines L1 and L2, and of the lines L3 and L4 are thus arranged in a complementary manner on these two lines. In other words, two contiguous row or column photodetectors are not simultaneously exposed under an aperture of the mask. In this way, the openings are spaced sufficiently apart from each other to limit the parasitic coupling between several detection channels. The image sensor 5 is synchronized with the movement of the surface S to be inspected so that the photodetectors distributed over the lines correspond to a plurality of measurement points arranged similarly along lines arranged in a direction perpendicular to the direction of inspection (I). Thanks to the complementary distribution of the chromatic filtering apertures between the lines, when the surface S is moved along the inspection direction I, the measurement points imaged on the detector combine very densely in the inspection field.

There is thus represented in FIG. 5 a first inspection field CI1 as well as the measurement points (in dotted lines) imaged on the image sensor 5 of this inspection field. The surface has been moved along the direction of inspection and a second inspection field CI2 has been shown as well as the measurement points in this field (in solid lines). The distribution over several complementary lines of the openings makes it possible, as the object moves, to carry out dense measurements in the inspection field.

Of course, the openings can be distributed in a complementary manner over a larger number of lines, which makes it possible to space these openings even further from each other and further limit the coupling phenomenon. For a given dimension of the photodetector array, this amounts to placing fewer photodetectors on a column, and therefore affecting the intensity quality of the image.

Advantageously, the confocal mask (6a, 6b) can comprise a plurality of groups of lines with a complementary distribution of the chromatic filtering openings. These groups of lines can comprise for example an identical distribution of chromatic filtering openings. Thus each measurement point of the object is imaged on the detector in a plurality of chromatic filtering apertures, sequentially, which makes it possible to accumulate more intensity or charges and to fully exploit the number of lines of the array of photodetectors.

The device as described makes it possible to obtain images in intensity, or in gray level, of the surface of the object, or in other words of its reflectivity.

Insofar as the chromatic system encodes the height of the object in wavelength, it is also possible to obtain depth information. This requires determining the wavelength of the radiation detected by the photodetectors. This can be implemented by employing a color image sensor, thus returning color information in addition to the intensity information of the detected radiation.

This approach can be implemented in different ways.

According to a first approach, a plurality of photodetectors are arranged under the openings of the mask, respectively provided with color filters, for example RGB. Each measurement point is then characterized by the intensity measurement in each of the spectra defined by these filters.

According to another approach, the photodetector (or photodetectors) under an aperture is equipped with a single color filter, but the nature of this filter varies from one column to another, along the line. The radiation emitted by adjacent measurement points of the surface S, corresponding to adjacent columns of the detector, is therefore detected by photodetectors respectively dedicated to a color.

The color information, even coarse, obtained using an RGB type filter, can advantageously be used by the electronic control unit 7 to estimate the elevation of the measurement points, and more specifically the distance separating the point measuring a reference plane of the device. The control unit 7 can therefore estimate an average distance separating the surface S from this reference plane. It can slave the movement along the optical axis AO of the mobile support 4 to this average distance estimate to maintain the inspection surface S in the depth of field of the chromatic system 3 while moving this surface S along the direction of inspection. I, during a measurement sequence.

The speed of movement of the surface S, depending on the direction of inspection can reach for example a value of the order of 100mm/second.

Of course, the invention is not limited to the embodiments described and variant embodiments can be added thereto without departing from the scope of the invention as defined by the claims.

Thus, the two opaque lighting and detection masks 6a, 6b can be replaced by a single mask, arranged in this case under the separating element 3b. The mask can for example be fixed directly under a separator cube or a reflecting blade, for example by depositing an opaque material on this optical part. In this alternative configuration, the openings of the single mask perform both the function of the lighting and chromatic filtering openings. The openings of this mask are then optically conjugated from the surface S of the object by the chromatic system 3, and optically conjugated from the image sensor 5.

Claims (14)

Device for inspecting (1) a surface (S) of an object, the device comprising:
- at least one polychromatic light source (20) for projecting an inspection beam onto the surface (S);
- at least one confocal mask (6a, 6b) intercepting the inspection beam and a beam reflected by the surface (S), the confocal mask (6a, 6b) having a plurality of chromatic filtering apertures;
- a chromatic system (3) spatially spreading the focusing of the inspection beam according to the wavelengths present, according to focusing planes along an optical axis (AO) in a depth of field, and intercepting the beam reflected by the surface (S) to project it onto a detection plane (P) conjugate to the focusing planes;
- a mobile support (4) for receiving the object and positioning the surface (S) in the depth of field of the chromatic system (3), the support (4) being controllable to move the surface (S) relative to the chromatic system (3) at least along an inspection direction (I);
- a timed integration image sensor (5) synchronized to the movement of the surface (S) along the inspection direction (I), the image sensor (5) comprising a matrix of photodetectors arranged in the detection plane (P), the chromatic filtering openings of the confocal mask (6a, 6b) illuminating part of the photodetectors. Inspection device according to the preceding claim, in which the chromatic filtering openings are arranged on the confocal mask (6a, 6b) to illuminate a plurality of photodetectors arranged on a column of the matrix corresponding to a plurality of measurement points arranged according to the direction of inspection (I). Inspection device according to one of the preceding claims, in which the chromatic filtering apertures are distributed in a complementary manner over at least two lines of the confocal mask (6a, 6b) to illuminate a plurality of photodetectors corresponding to a plurality of measurement points arranged along at least two lines arranged along a direction perpendicular to the direction of inspection (I). Inspection device according to the preceding claim, in which the confocal mask (6a, 6b) comprises a plurality of groups of at least two lines comprising chromatic filtering openings distributed in a complementary manner over the said at least two lines. Device according to one of the preceding claims comprising a confocal lighting mask (6a) placed in the inspection beam and a confocal detection mask (6b) placed in the reflected beam, the confocal lighting mask (6a) and the confocal detection mask (6b) being respectively placed in a conjugate plane of the focusing planes with respect to the chromatic system (3). Device according to the preceding claim, in which the confocal detection mask (6b) is produced by depositing at least one material on the surface of the image sensor (5). Inspection device according to one of Claims 1 to 4 comprising a single confocal mask, placed in a plane jointly conjugate with the detection plane (P) and the focusing planes vis-à-vis the chromatic system (3). Inspection device according to one of the preceding claims, in which the polychromatic light source (20) comprises a halogen lamp or a strip of light-emitting diodes, associated with a diffusion device (21) to homogenize the intensity of the beam of inspection. Inspection device according to one of the preceding claims, in which the chromatic system (3) comprises a chromatic lens (3a). Inspection device according to the preceding claim, in which the chromatic objective (3a) comprises a lens or a combination of lenses, at least one diffraction lens and/or at least one metal lens. Inspection device according to one of the preceding claims, in which the chromatic system (3) comprises a separating element (3b). Inspection device according to the preceding claim, in which the separating element (3b) is a separating cube or a semi-reflecting plate. Inspection device according to one of the preceding claims, in which the photodetectors are provided with a color filter. Inspection device according to the preceding claim, in which the chromatic filtering openings are arranged to each illuminate a plurality of photodetectors provided with different color filters.