EP2208033A2

EP2208033A2 - Multi-spectral sensor

Info

Publication number: EP2208033A2
Application number: EP09715284A
Authority: EP
Inventors: Norbert Weber; Stephan Junger; Wladimir Tschekalinskij
Original assignee: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Current assignee: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Priority date: 2008-02-29
Filing date: 2009-02-25
Publication date: 2010-07-21
Also published as: WO2009106316A3; DE102008011793A1; EP2226648A3; WO2009106316A2; EP2226648A2

Abstract

The invention relates to a multi-spectral image sensor having a two-dimensional array of super-pixels, wherein each super-pixel has at least five sensor elements (11), each comprising a pixel sensor (14), a filter structure (12) having at least one structured layer made of metal or polycrystalline semi-conductor material, which, in response to the electromagnetic radiation of a wavelength region, results in a higher transmission through the filter structure to the pixel sensor (14) than wavelengths surrounding the wavelength region, wherein the at least five sensor elements (12) are jointly integrated on a semi-conductor substrate (16) and are configured on different wavelength regions in pairs.

Description

MuItispektralsensor

description

The present invention relates to a multi-spectral sensor with spectral filter structures of at least one structured layer of metal or polycrystalline semiconductor material and the at least one structured layer associated with pixel sensors.

At present, optical spectrometers usually consist of a construction, as shown schematically in FIG. 33. An optical system 431, e.g. a lens collects and transmits light to a light entrance port 432 which defines the resolution of the spectrometer 430. Subsequently, the light strikes a dispersion unit 433 and a line sensor 434, which detects the spectrally fanned out light. The dispersive element 433 is either a prism or a grating and has the task of deflecting the individual spectral components of the light at different angles, so that a sufficient separation of the spectral lines takes place at a certain distance from the dispersive element 433 and with the line sensor 434 can be detected.

For simple spectrometer tasks with only a few spectral lines to be measured, instead of the dispersion unit 433, color filters can also be used to realize the spectral separation. These color filters may either be deposited directly on the detector 434 or may be e.g. located in a housing cap of the detector 434.

In conventional chip-size spectrometers, a gradient filter is usually used, which leads to a location-dependent spectral filtering, as shown schematically in FIG. 34. For this purpose, however, additional process steps, such as the precise adjustment and gluing of optical filter elements are required. Another approach to achieving laterally varying spectral transmission is to use a wedge-shaped resonator between Bragg reflectors, as shown schematically in Figs. 35a, b.

Several simulations and experiments have been published in recent years, which also confirm a spectral selectivity of structures for the visible wavelength range, which have so-called sub-wavelength openings in multi-level structured metal layers. The publication PB Catrysse and BA Wandell, "Integrated color pixels in 0.18-μm complementary metal oxide semiconductor technology", describes a color sensor based on periodically structured metal layers in the context of CMOS technology in that a spectral sensitivity is clearly dependent on geometric parameters (width and period of stripes of a lattice structure) of a sub-wavelength structure, and that steep filter edges, eg for a low-pass filter, can already be realized with a relatively simple structure such as a line grid.

With the aid of sub-wavelength-structured metal layers of a CMOS process and the pn junctions present there, it is possible to realize a spectrally sensitive photodiode. FIG. 36 shows an example of a layer structure of a CMOS process.

FIG. 36 shows an intermediate product 460 of a CMOS process which has a substrate 461, in particular a semiconductor substrate, in which a pixel sensor 462 (eg photodiode) is introduced. In this case, the pixel sensor 462 is arranged in a plane 463 which encompasses a field concentration region (a type of focal plane known from classical optics) of the overlying layer stack of metallic layers 464 and dielectric layers 465. FIG. 36 shows by way of example only three metallic see structured layers 464-1 to 464-3 and three dielectric layers 465-1 to 465-3, which may also be patterned. With a corresponding array-shaped structuring of the individual metal layers, which can be defined in the context of a chip design (eg image 36 right: top layer: polygons, middle layer: circular openings, bottom layer: strip-shaped), a defined spectral transmission is obtained.

The concept of the spectrometer with a dispersive unit usually requires the use of three different optically active components (entrance optics, dispersive element, line sensor). These components must be carefully adjusted and assembled to achieve the desired effect. On the one hand, this requires a certain amount of effort during assembly and, moreover, it requires a relatively large amount of space despite the approaches used by a microsystem-compatible structure. In addition, the individual components, especially the detector line and the grid, which is often also produced by microsystem technology, relatively expensive. The positioning and fixing of the optical components requires a high mechanical precision, which also leads to high costs. Therefore, the existing solutions are hardly suitable for use in large numbers or in the case of the required extremely small size.

Spectrometers that are based on color filters can in principle be made smaller or cheaper, but have the disadvantage that the spectral resolution is limited at the same time small size and therefore only relatively few wavelengths (about 3-5) can be meaningfully measured with it. The construction technique requires either a subsequent application of color filters on detector chips or color films in the housing and is therefore also associated with effort. In addition, the light must be perpendicular to the sensor surface to achieve good filtering effect. Therefore, an external collimating optics is needed. In view of the stated disadvantages of the prior art, the object of the present invention is therefore to provide an improved concept for the construction of multispectral sensors or spectrometers, which enables the realization of multispectral sensors or spectrometers of small size and high spectral resolution.

This object is achieved by an integrated multispectral sensor having the features of patent claim 1, a method according to patent claim 37, a multispectral image sensor according to patent claim 38 and a method according to patent claim 44.

The present invention is based on the finding that a multispectral sensor or spectrometer with the desired properties can be realized by providing a plurality of pixel sensors (eg at least five), in the form of a one-dimensional or two-dimensional sensor array, at least spectral filter structures associated with the pixel sensors a structured metal layer is integrated on a semiconductor substrate, so that by different spectral selectivity of the spectral filter structures, a multi-spectral sensor, which can detect arbitrary spectral lines simultaneously, can be constructed.

Embodiments of the present invention include a multi-spectral image sensor having a two-dimensional array of super pixels, each super pixel having at least five sensor elements. In this case, a first sensor element has a first pixel sensor and a first filter structure, with at least one structured metal layer which, in response to electromagnetic radiation of a first wavelength range, results in a higher transmission through the first filter structure to the first pixel sensor than for the first wavelength range. Bending wavelengths. A second sensor element has a second pixel sensor and a second filter structure with at least one structured metal layer which, in response to electromagnetic radiation of a second wavelength range, results in a higher transmission through the second filter structure to the second pixel sensor than wavelengths surrounding the second wavelength range. In preferred embodiments, the first and second sensor elements are integrated together on a semiconductor substrate.

Further embodiments of the present invention comprise a multispectral image sensor for detecting a two-dimensional image field, comprising a line sensor having a plurality of one-dimensionally arranged sensor elements for spectrally detecting a geometrical line, each sensor element having a pixel sensor and a filter structure with at least one structured metal layer which is responsive to electromagnetic Radiation of a wavelength range associated with the sensor element results in a higher transmission through the filter structure to the pixel sensor than wavelengths surrounding the assigned wavelength range. Each sensor element is assigned a different wavelength range. The sensor elements are preferably integrated together on a semiconductor substrate. Further, the multispectral image sensor includes means for mapping a line from the two-dimensional image field to the line sensor, and means for causing a line imaged on the line sensor to traverse the two-dimensional image field.

The device for imaging a line serves to project the line onto an image plane in which the line detector is located. It can for example have a lens or a concave mirror.

The means for causing a line imaged on the line sensor to scan through the two-dimensional image field. running, practically produces a scan of different lines from the two-dimensional image field. This can be done by moving the two-dimensional image field itself, for example by a conveyor or conveyor belt, or by tilting a suspended on an axis of rotation, electromagnetic radiation reflecting component, whereby different lines of the two-dimensional image field can be imaged on the line detector.

According to one embodiment, the spectral filter structures may be designed to detect electromagnetic radiation in each case of a predetermined wavelength range. The pixel sensors are designed, for example, as photodiodes.

According to one exemplary embodiment, the structured metal layers of the spectral filter structures have properties of a photonic crystal. A photonic crystal is to be understood below to mean a three-dimensional periodic structure whose periodically arranged structural elements have dimensions and distances from one another which are of the order of magnitude of a predetermined wavelength range for electromagnetic radiation which can be transmitted through a photonic crystal to a pixel sensor assigned to it. Photonic crystals comprise structured metals, semiconductors, glasses or polymers and force electromagnetic radiation, in particular light, by means of their specific structure to propagate in the medium in the manner required for a component function. Periodically according to exemplary embodiments, dielectric and / or metallic structures whose period length is adjusted so as to influence the propagation of electromagnetic radiation, in particular light, in a manner similar to the periodic potential in semiconductor crystals, propagate electrodes. This leads to the fact that electromagnetic radiation or light of certain wavelengths can not propagate in the photonic crystal. The- These wavelengths are then forbidden. The spectral filtering effect of photonic crystals has been known for some years and confirmed by experiments. For example, results in Air-bridged phototonic crystal slabs at visible and near-infrared wavelenghts KB Crozier, Virginie Lousse, Onur Kilic, Sora Kim, Shanhui Fan, and Olav Solgaard show that not all wavelengths are alike for periodically structured metal surfaces Passing through such structures when the structures are smaller than the wavelength From the work "The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment" K. Lance Kelly, Eduardo Coronado, Lin Lin Zhao, and George C. Schatz concludes that the spectral properties of such periodic structures depend strongly on the shape of the individual structural elements. The focusing effect of three-dimensional photonic crystals (ie, a deflection of electromagnetic radiation from the edge towards the center of the photonic crystal) was shown in "Analysis of focussing effects of 3-D photonic crystal lens by the method of moments" Chaowei Su, Chi Hou Chan , Ka Fai Chan.

According to exemplary embodiments of the present invention, in addition to a plurality of arrayed or arrayed pixel sensors on a semiconductor substrate, each pixel sensor is assigned and integrated with at least one photonic crystal or a periodic array of photonic crystals from a layer stack of structured metallic dielectric layers, with op - table filtering and focusing properties. For this purpose, the structured metal layers have structure or microelements whose dimensions and distances from each other are of the order of the respective predetermined wavelength range for which the associated integrated spectral filter structure is in the form of at least one photonic crystal. The microelements of the metal layers are periodically arranged in three dimensions. According to embodiments, adjacent micro elements of adjacent metal layers are formed identically for a predetermined wavelength range and lie on a common optical axis. Microelements may according to embodiments be micro-openings with dimensions and distances in the respectively provided transmission wavelength range. According to embodiments, the microelements comprise so-called split-ring resonators with dimensions and distances in the respective predetermined transmission range.

An electromagnetic radiation incident on a side of the at least one photonic crystal of a spectral filter structure facing away from a pixel sensor or a photodiode is filtered by the three-dimensional periodic structure of the at least one photonic crystal acting as a filter structure so as to be close to the at least one predetermined wavelength range Pixelsensors only electromagnetic radiation of the predetermined wavelength range is receivable. That is, the pixel sensor is disposed in a field concentration region (a quasi focal region, if one would consider the photonic crystal as a lens) of the electromagnetic radiation filter structure. Due to the focusing effect of the filter structure or of the at least one photonic crystal, the electromagnetic field of the predetermined wavelength range is concentrated in the vicinity of the pixel sensor.

In order to improve the spectrally selecting effect of a spectral filter structure according to exemplary embodiments, a metal layer with an opening can be arranged between a pixel sensor and the filter structure with the at least one photonic crystal. In this case, the center of the opening, which may in particular be a circular opening, is preferably located on the optical axis of the filter structure (microlens based on photonic crystals) near the field concentration range. According to exemplary embodiments, the distance between the pixel sensors and the photonic crystals acting as spectral filter structures is less than 20 μm and preferably less than 8 μm. For 0.18 μm CMOS processes, the distance between a pixel sensor and a spectral filter structure is less than 2 μm.

From a plurality of integrated sensor elements acting as optical sensors, a multispectral sensor can be constructed which can simultaneously detect any spectral lines by integrating a plurality of sensor elements made of spectral filter structures with photonic crystals and pixel sensors in a plane adjacent to one another. This results in an array or a matrix of sensor elements with photonic crystals. The photonic crystals of the individual sensor elements can be adjusted to different wavelength ranges. For a multispectral sensor, adjacent sensor elements are set to light of different wavelengths.

According to a further exemplary embodiment of the present invention, in the case of the sensor elements of a multispectral sensor, a respective pixel sensor is integrated together with a layer stack of dielectric layers and structured metal layers on a substrate, the structured metal layers having a zone plate structure, such as e.g. an array of zone plates associated with a pixel sensor.

A zone plate has a focusing effect. From the theory of the zone plate, it follows that with a corresponding ratio of radii of transparent and non-transparent zones at a certain distance from the zone plate for a predetermined wavelength or a predetermined wavelength range, a concentration of the electromagnetic radiation or the light is similar to one Focal point arises. A pilot placed at this point ^

The xelsensor, for example in the form of a photodiode, can now be covered by a structured with zone plate structure metal layer so that only the electromagnetic radiation or the light of the desired wavelength λ _deS or the desired wavelength range meets at least approximately lossless on the pixel sensor, while other wavelengths filtered out become.

By means of an optional, further structured metal layer, for example with an opening, between the metal layer structured with zone plate structure and the pixel sensor, a spectral separation can be further improved compared to exemplary embodiments without this further metal layer.

An electromagnetic radiation incident on a side of the zone layer structure-structured metal layer remote from the pixel sensor or the photodiode is filtered by the zone plate structure tuned to the predetermined wavelength range, so that only electromagnetic radiation of the predetermined wavelength range can be received in a vicinity of the pixel sensor. That is to say that the pixel sensor is arranged in a field concentration region-also sometimes referred to as a focal point region-of the zone plate in the following. Due to the focusing effect of the zone plate, the electromagnetic field of the predetermined wavelength range is concentrated near the pixel sensor.

According to exemplary embodiments, the distance between the pixel sensor and the nearest zone layer structure of the metal layer of a sensor element is less than 20 μm or is between 6 and 10 μm.

For example, from a plurality of such sensor elements, an integrated multispectral sensor can be constructed by connecting a plurality of sensor elements with zone plates and pixel sensors in a plane adjacent to one another. integrated. In this case, individual zone plates from the array of the individual sensor elements can be set to different wavelength ranges.

According to a further exemplary embodiment of the present invention, a single sensor element of the integrated multispectral sensor or spectrometer is formed from a pixel sensor and a metal structure covering the pixel sensor, for example one or more structured metal layers which are structured such that for a predetermined wavelength range predetermined wavelength can form a plasmon-polariton resonance effect. Through a sub-wavelength opening in the patterned metal layer, an electromagnetic field concentration can form for the predetermined wavelength due to the plasmon-polariton resonance effect in the vicinity of the pixel sensor, which can then be detected by the pixel sensor.

The plasmon-polariton resonance effect results in a so-called extraordinary optical transmission that can take place through slits or holes in metals that are faster than a wavelength of the predefined wavelength range or the predefined resonance wavelength. When electromagnetic radiation outside of the predefined wavelength range, ie at a different wavelength than the predefined resonance wavelength, encounters such a structured metal layer, it spreads beyond a second side of the structured metal layer only at a sub-wavelength aperture as if it were There it has been diffracted isotropically, ie it spreads evenly in all directions. But most of it is reflected back or scattered on the metal on the first page. However, when the sub-wavelength opening on the first side of the patterned metal layer is surrounded, for example, by periodic grooves, the dimensions of which are tuned to the predefined wavelength range, it spreads starting from the sub-wavelength. Wavelength opening directed beyond the second side of the structured metal layer for electromagnetic radiation of the predefined wavelength range directed strongly isotropic electromagnetic radiation.

This phenomenon results from so-called surface plasmon resonance. A surface plasmon is a density variation of charge carriers at the boundary of semiconductors or metals to dielectric media and is one of many interactions between light and a metallic surface, for example.

According to embodiments, the metal of the metal structure together with a surrounding dielectric has an effective negative dielectric constant. Negative effective dielectric constants at frequencies of electromagnetic radiation in the optical spectral range include, for example, aluminum (Al), gold (Au), silver

(Ag) and copper (Cu) on.

A metal structure has, for example, a structured metal layer with an opening with sub-wavelength dimensions, hereinafter also referred to as sub-wavelength opening, and rotationally symmetrical or parallel grooves or corresponding projections or elevations arranged periodically around the sub-wavelength opening embedded in a dielectric so arranged to produce the surface plasmon-polariton resonance effect for the predetermined wavelength range in the patterned metal layer. In this case, a sub-wavelength opening is an opening having a width or a diameter smaller than a wavelength of the predefined wavelength range or the resonance wavelength.

According to embodiments, the sub-wavelength opening may be rotationally symmetrical or circular or slot-shaped. A diameter or a width of the sub-wavelength opening is smaller than the resonance wavelength. lenlänge. In addition to a slit-shaped sub-wavelength aperture, periodic parallel grooves are arranged in the patterned metal layer, where distances and dimensions of the grooves are suitable for producing the surface plasmon-polariton effect for the predetermined wavelength range. Circumferential annular grooves are arranged in the patterned metal layer around a circular sub-wavelength aperture, with distances and dimensions of the annular grooves suitable for producing the surface plasmon-polariton effect for the predetermined wavelength range.

Another way of structuring the metal layer suitably is to introduce a one-dimensional or two-dimensional array of periodically arranged sub-wavelength openings into the metal layer.

From a plurality of sensor elements according to embodiments of the present invention, a multi-sensor sensor can be constructed by integrating the plurality of sensor elements in a plane adjacent to each other. In this case, the metal layer structures of the individual sensor elements can be set to different wavelength ranges.

With exemplary embodiments of the present invention, it is possible to construct a multispectral sensor which can detect arbitrary spectral lines at the same time, without the need for coating the sensor or the sensor chip. The multispectral sensor can be integrated into any CMOS processor that has a minimum feature size of 0.18 μm or smaller. For the detection of light at longer wavelengths, eg in the near infrared range (800 nm to 1100 nm), the multispectral sensor can also be fabricated with larger structures, as long as the structure size is not greater than half the wavelength of the light to be measured. A multi-spectral sensor or spectrometer realized by the inventive concept is constructed from a photodiode line or a two-dimensional photodiode array. Above each photodiode a corresponding narrow-band filter is realized, which is formed on the basis of structured metal and / or dielectric layers. The structure sizes are in the sub-lambda range (relative to the wavelengths to be detected). The entire filter arrangement covers a specific spectral range, so that the photodiode array with the filters has the same effect as a dispersive element (prism or grating) in spectroscopy.

For the construction of the multispectral sensor or spectrometer a sensor chip is used, which was manufactured with a standard CMOS technology with sufficiently small structure size. The sensor chip is constructed as an array of individual sensors. The individual sensor elements or the overlying filter layers are designed so that they each have a bandpass characteristic. The filters are realized according to one of the structures described above (photonic crystal, zone plates, plasmon-polariton resonance effect). With a variety of such elements, an optical filter bank is constructed with underlying detectors.

A spectrometer may be implemented according to embodiments with or without an additional optical system in front of the receiver. The individual sensor elements can be designed so that they have a focusing effect, so that the multi-spectral sensor is sensitive only to a certain receiving solid angle. According to embodiments, the sensor elements are arranged so that the multi-spectral sensor can be well illuminated either with coupling optics or with an optical fiber. The geometry of the arrangement can be freely defined in the chip design. The multispectral sensor is therefore able to detect many spectral lines simultaneously and to detect. According to embodiments, an analog or digital signal processing circuit can also be integrated with each pixel on-chip.

Embodiments of the present invention make it possible to realize a spectrometer which combines the functions of spectral separation, light detection and light bundling all on one chip. In this case, embodiments can be constructed such that a spectrometer is not or only slightly larger than def ^r underlying underlying multispectral detector chip.

A multispectral sensor or spectrometer according to exemplary embodiments of the present invention can do without external entry optics or beam collimation and measure the corresponding spectrum in a solid angle.

Integrated multispectral sensors or spectrometers according to embodiments of the present invention can be designed such that a plurality of spectral ranges can be arbitrarily defined and measured on a chip, even with different spectral resolutions. The individual spectral channels can have a very small spectral width, much smaller than, for example, with an RGB sensor on a CMOS chip. Such a narrow spectral width can otherwise only be achieved with an expensive interference filter; in addition, a complex adjustment of the filter to the sensor must then be undertaken.

Exemplary embodiments thus make it possible to construct a chip-size spectrometer that can be produced cost-effectively and in large quantities in CMOS technology. This opens up new application possibilities in the mass application, which requires extremely small size and / or low costs. It is even a disposable measuring chip conceivable that can be manufactured extremely inexpensively. Conceivable applications are, for example, monitoring of the fatigue state of motorists by spectroscopic measurement of the blood in a finger, multi-gas analyzes in food monitoring, detection of certain organic deviations (rotten meat, plant diseases, etc.) and much more. For example, embodiments of the present invention also enable the construction of a multi-spectral camera. Images that can be created contain a multiple of spectral information compared to a standard camera chip based on RGB.

Preferred embodiments of the present invention will be explained in more detail below with reference to the accompanying drawings. Show it:

1 shows a schematic representation of part of an integrated multispectral image sensor with superpixels having a first and a second sensor element according to an exemplary embodiment of the present invention;

Fig. 2a is a schematic representation of a structure and a function of an integrated multispectral sensor in line form according to an embodiment of the present invention;

2b shows a schematic representation of a construction of a multispectral image sensor with line detector according to an exemplary embodiment of the present invention;

FIG. 2c shows a schematic side view of a system for spectral examination of a two-dimensional surface according to an embodiment of the present invention; FIG.

Fig. 2d is a schematic side view of a system for spectral examination of a two-dimensional surface according to another embodiment of the present invention; 3 is a schematic representation of a matrix-shaped arrangement of sensor elements of a multispectral sensor according to an exemplary embodiment of the present invention;

4a shows a schematic representation of a spectrally sensitive array of 3x3 pixels according to an embodiment of the present invention;

4b shows a schematic representation of a system for determining three-dimensional images with a two-dimensional array of superpixels, according to an exemplary embodiment of the present invention;

4c is a schematic representation of a row of superpixels of a 3D image sensor, according to an exemplary embodiment of the present invention;

5 is a schematic representation of illumination possibilities of a spectrometer according to embodiments of the present invention;

6 is a perspective view of a sensor element having a filter structure with an array of photonic crystals and a pixel sensor according to an embodiment of the present invention;

FIG. 7 shows a plan view of the sensor element according to FIG. 6; FIG.

8 is a side view of a CMOS-fabricated layer stack of pixel sensor, metal layers, and dielectric layers according to one embodiment of the present invention;

9a is a side view of a section of a sensor element with at least one photonic crystal according to an embodiment of the present invention; FIG. 9b shows a side view of three adjacently integrated sensor elements according to FIG. 9a; FIG.

10a is a plan view of a metal layer with split-ring resonators according to an embodiment of the present invention;

10b is a plan view of a metal layer with split-ring resonators and underlying metal layer with hole opening, according to an embodiment of the present invention;

11a shows a side view of a section of a sensor element with at least one photonic crystal and additional metal layer with opening between photonic crystal and pixel sensor according to an exemplary embodiment of the present invention;

FIG. IIb shows a side view of three adjacently integrated pixel elements according to FIG. IIa; FIG.

12 is a schematic representation of an electromagnetic field concentration in the vicinity of an opening provided with a metal layer according to an embodiment of the present invention.

Fig. 13 is a schematic side view of three-dimensional microelements;

14 is a schematic perspective view of a zone plate structure sensor element according to an embodiment of the present invention;

FIG. 15 a is a side view of a CMOS integrated sensor element with zone plate structure according to an embodiment of the present invention; FIG. 15b is a side view of a CMOS-fabricated integrated sensor element with zone plate structure according to another embodiment of the present invention;

16 is a plan view and a side view of a structured metal layer having a zone plate structure according to an embodiment of the present invention;

17 is a schematic illustration of the focusing operation of the zone plate structure according to an embodiment of the present invention;

18 shows a side view of a sensor element integrated in CMOS technology with metal layers provided with two zone plate structures according to a further exemplary embodiment of the present invention;

19 shows a side view of a multispectral sensor integrated in CMOS technology with a plurality of integrated sensor elements, according to an exemplary embodiment of the present invention;

20a is a top view of a patterned metal layer having a plurality of zone plate structures according to an embodiment of the present invention;

FIG. 20b shows a side view of an integrated sensor element with a structured metal layer according to FIG. 20a; FIG.

21 is a schematic perspective view of an integrated sensor element with plasmon-polariton resonance

Effect according to an embodiment of the present invention;

FIG. 22 is a sectional view of a patterned metal layer having sub-wavelength structures and a pixel-end. FIG. sor according to an embodiment of the present invention;

23 shows a detailed sectional view of a sensor element with structured metal layer with sub-wavelength structures according to an exemplary embodiment of the present invention;

FIG. 24 is a perspective view of a patterned metal layer according to an embodiment of the present invention; FIG.

25 shows a perspective view of a structured metal layer according to a further exemplary embodiment of the present invention:

FIG. 26 is a schematic diagram for explaining the operation of the structured metal layer according to an embodiment of the present invention; FIG.

FIG. 27 shows a schematic representation of transmitted electromagnetic radiation for different wavelengths; FIG.

28 is a schematic top and side view of a sensor comprising a plurality of sensor elements, according to an exemplary embodiment of the present invention;

29 is a schematic plan view of a structured metal layer with a slot-shaped opening according to an embodiment of the present invention,

Fig. 30 is a schematic view of a metal layer having a two-dimensionally periodic array of sub-wavelength openings;

31 is a schematic plan view and side view of a multispectral sensor including various sensor elements. sors according to an embodiment of the present invention;

32 shows a detailed sectional view of a sensor element with two structured metal layers and an interposed dielectric layer with sub-wavelength structures, according to an exemplary embodiment of the present invention;

Fig. 33 is a schematic representation of a spectrometer according to the prior art;

Fig. 34 is an illustration of a chip size spectrometer according to the prior art;

35 is an illustration of circular resonators between Bragg reflectors for achieving varying spectral transmissions according to the prior art;

36 shows an illustration of a layer structure of a CMOS process with structured metal planes according to the prior art; and

37 shows a side view of a layer stack of pixel sensor produced using CMOS technology and layers of metal or polycrystalline semiconductor material according to a further exemplary embodiment of the present invention.

With regard to the following description, it should be noted that in the different exemplary embodiments, identical or equivalent functional elements have the same reference numerals, and thus the descriptions of these functional elements in the various exemplary embodiments shown below are interchangeable. 1 schematically shows a part of an integrated multiplex spectral sensor 10 according to an embodiment of the present invention.

The integrated multispectral sensor 10 includes a first sensor element 11-1 for selecting a first predetermined wavelength range and a first predetermined wavelength and a second sensor element .lambda..sub.i 11-2 for selecting a second predetermined wavelength range or a wavelength _x2. The first sensor element 11-1 has a first pixel sensor 14-1 and a first filter structure 12-1 with at least one structured metal layer which, in response to electromagnetic radiation of the first wavelength range λi, has a higher transmission through the first filter structure 12-1 to the first The first pixel sensor 14-1 gives wavelengths surrounding the first wavelength range. The second sensor element 11-2 has a second pixel sensor 14-2 and a second filter structure 12-2 having at least one structured metal tallschicht, which in response to electromagnetic radiation of the second wavelength range _λ Σ a higher transmission through the second filter structure to 12-2 The second pixel sensor 14-2 results in wavelengths surrounding the second wavelength range. The first sensor element 11-1 and the second sensor element 11-2 are integrated together in a semiconductor substrate 16.

As already explained, the first and second filter structures 12-1, 12-2 can each be formed as a photonic crystal. According to further embodiments, the at least one metal layer of the first and second filter structures 12-1, 12-2 may each have a zone plate structure. According to still further embodiments, the at least one metal layer of the first and second filter structures 12-1, 12-2 may each be patterned to produce a plasmon-polariton resonance effect. On the various construction options of the Sen- Sorelemente 11-1, 11-2 will be discussed in more detail below.

The sensor elements 11-1, 11-2, of which only two are shown by way of example only in FIG. 1, can be arranged in one-dimensional line form or two-dimensionally in matrix form in embodiments in order to obtain a multispectral image sensor.

First, Fig. 2a schematically shows a plan view of a line-shaped structure of a multi-spectral line detector 20 according to an embodiment of the present invention.

The multi-spectral line detector 20 comprises a photodiode array of N photodiodes (not shown) integrated on the semiconductor substrate 16, which are located below the N-illustrated filter structures 12-1, 12-2, ..., 12-N. That is, above each photodiode 14-n (n = l, 2, ..., N), an (array-shaped) filter structure 12-n (n = l, 2, ..., N) is arranged, which in turn from three-dimensional structured metallic and dielectric layers is constructed. The photodiodes and the filter structures 12-1, 12-2,..., 12-N together form respectively sensor elements 11-n (n = 1, 2,..., N). The filter structures 12-n (n = 1, 2,..., N) are dimensioned as optical bandpass filters such that each of the N filter structures 12-n (n = 1, 2,..., N) has a predefined spectral Transmission is achieved, as indicated in Fig. 2a (bottom). As will be described in detail, the spectral transmission depends only on the geometric, three-dimensional shape of the structured metal and / or dielectric layers of the filter structures 12-n (n = 1, 2,..., N).

FIG. 2b schematically shows an embodiment of a multispectral image sensor for detecting a two-dimensional image field with a multispectral line detector 20. The multispectral image sensor according to FIG. 2b comprises a movable, reflective component 21 on which light rays 22 from a geometric line whose spectral distribution is to be determined are incident. The reflective component 21 may comprise, for example, a mirror or a metal. The reflective component 21 is rotatably mounted about an axis 23. The multi-spectral line detector 20 of a plurality of sensor elements 11-1, 11-2, of which only two are provided with reference numerals for the sake of clarity, is arranged to receive the light reflected by the movable reflecting component 21 from the line. In this case, the multispectral line detector 20 is arranged in a plane passing through the axis of rotation 23 of the reflective component 21. The spectral resolution of the multispectral image sensor can be adjusted either by the removal of the multispectral line detector 20 to the reflective component 21, or by an imaging optical system between the reflective component 21 and the line detector 20, which is not shown here for the sake of clarity. If the reflective component 21 is, for example, a concave mirror, an additional imaging optical system, for example, can be used. As a lens can be dispensed with. In a simple mirror as a reflective component 21 is between mirror and multispectral line detector 20 z. B. still a lens necessary to image the light 22 of the geometric line on the multi-spectral line detector 20.

For the movement of the movable, reflective component 21, a suitable control 24 is provided, which for driving with the movable, reflective component 21 z. B. is coupled via an inductive, capacitive or mechanical coupling. To the driver 24 on the one hand and the multi-spectral line detector 20 on the other side is coupled a control unit 25 which controls the exposure timings at which the multi-spectral line detector 20 takes photographs relative to the movement of the reflective component 21. For this purpose, the Control 24 (via a known relationship between control and deflection or by means of a specially provided detection device) the instantaneous position of the reflective component 21 and outputs to the control unit 25, a signal indicating the current position. The control unit 25 in turn determines the exposure times at which the multi-spectral line detector 20 is to take recordings, and for this purpose sends triggering signals to the multispectral-line detector 20.

Each sensor element 11-n (n = 1,..., N) detects at a given time a different spectral component of a light beam from a line of a surface which is mirrored onto the multi-spectral line detector 20 due to the deflection of the reflective component 21. If light, starting from a line which runs essentially parallel to the multispectral line detector 20, impinges on the reflecting component 21 at a suitable angle of incidence α, this is reflected by the reflecting component 21 according to the known physical law angle of incidence = angle of reflection. Because the multispectral line detector 20 is located at the angle of incidence α which is the same in terms of the angle of incidence relative to the reflective component 21, the multispectral line detector 20 can spectrally scan the light reflected and imaged on it by an optical system (concave mirror, lens).

With reference to FIG. 2 a, according to the invention, to determine the spectral distribution of the light, starting from a geometric line, a first image is first taken by the multispectral-line detector 20. Each sensor element 11-n (n = 1,..., N) acquires a different spectral component of the reflected light for this recording. The multi-spectral line detector 20 outputs the result of the first recording, the result being shown schematically at 26 as a graph in which the intensity I (λ, x) is plotted against the wavelength λ and in which an exemplary intensity profile is assumed. After the first shot, the driver 24 moves the reflective member 21 to another position. The multiplex spectral line detector 20 takes a second picture which corresponds to a second geometric line. The result of the second recording or exposure is shown schematically in a graph 27, wherein in turn the intensity I (λ, x) is plotted against the wavelength λ. The two recordings 26 and 27 are forwarded to a combination device 28 which switches both with the multispectral line detector 20 in order to obtain therefrom the intensity values of each detector element at each exposure and via the control unit 25 with the drive 24 from to obtain one of the two pieces of information regarding the position of the reflective component 21 at the exposure times, and which based on the images 26 and 27 provides a result corresponding to the determination of the spectral distribution of the light beams from the two geometric lines , In the manner described, light beams of any number of geometric lines can be spectrally decomposed by deflecting the reflective component 21. The size of an angle increment between two discrete deflection angles depends on the desired geometric resolution.

With reference to FIGS. 2 c and d, embodiments of systems according to the invention for examining a geometrical surface will be described below with reference to a possible application example. The arrangement are shown schematically in side view.

It should be mentioned at this point that the described geometric lines and surfaces to be examined are generally projection lines and surfaces. That is, it does not examine the lines and surfaces themselves, but objects that are at least partially imaged on these lines and / or surfaces. FIG. 2c shows different objects 16 and 17 to be inspected which are located on a surface 18. A linear region 19 is irradiated by a light source (not shown). Light rays 22 reflected by different points of the linear region 19 impinge on a rotatably mounted reflective element 21, where they are reflected towards an imaging optic 29. In order to detect the spectral properties of the reflected light, the multi-spectral line detector 20 is mounted in the image plane of the imaging optical system 29. Both the exposure timings of the multi-spectral line detector 20 and the movement of the reflective element 21 are controlled by a control device (not shown) connected to the multi-spectral line detector 20 and the reflecting element 21. By deflecting the reflecting element 21 about its axis of rotation 23, a plurality of lines 19 can be detected spectrally in order to determine the spectral properties of the surface 18 or of the objects 16, 17. That is, the rotatably suspended reflective element 21 corresponds to means for causing a line imaged on the multispectrum line detector 20 to pass through the two-dimensional image field 18.

FIG. 2 d shows another embodiment in which the means for causing a line imaged on the line sensor 20 to pass through the two-dimensional image field is a conveyor belt 15.

FIG. 2d shows different objects 16 and 17 to be inspected, which move on a conveyor 15 at a speed v. A linear region 19 is irradiated by a light source (not shown). Light rays 22 reflected by different points of the linear region 19 strike an imaging optical unit 29, eg a lens. To detect the spectral properties of the light emanating from the line 19, a multi-spectral line detector 20 is mounted in the image plane of the imaging optical system 29. The exposure times of the multi-spectral line detector 20 are controlled by a controller (not shown) connected to the multi-spectral line detector 20.

With regard to further possible applications, it is also conceivable that the multispectral-line detector 20 itself is moved relative to a surface to be analyzed. For example, applications in satellites or other earth observation missiles are conceivable in which, for example, a landscape is limited to optical features, such as e.g. characteristic plant properties (for example the color of the flowers). Here, too, the spectral analysis of a two-dimensional surface is finally achieved by scanning a one-dimensional region and the relative movement taking place perpendicular thereto with a slow relative velocity.

Application examples of the form with fixed multispectral line detector 20 and moving goods are numerous in the recycling industry in the selection of plastic or paper waste, in agriculture in the selection of crops (eg potatoes / stones) or in the food and pharmaceutical industries , Furthermore, a monitoring of flowing waters is conceivable in that the multi-spectral line detector 20 is attached, for example, to a bridge above the water body. Thus, a river flowing under the bridge can be monitored for ships, oil spills, etc.

The inspection can be done with or without additional light source. Accordingly, the spectroscopic methods of emission, reflection, absorption measurement, fluorescence spectroscopy or so-called Raman spectroscopy and / or related methods can be used. It is essential that certain wavelengths or wavelength ranges are evaluated by the optical signals impinging on the multispectral line detector 20. In general, it is possible to increase the imaging quality of a linear region to be imaged onto the multispectral-line detector 20, for example by preventing the entry of light beams into the multispectral-line detector 20 between every two successive scanning times of the multispectral-line detector 20. This can be done, for example, with the use of an optical shutter.

At this point, it should be emphasized that a multispectral image sensor for detecting a two-dimensional image field could also be realized, for example, simply with a superpixel rotatably suspended to two orthogonal axes for spectrally detecting a point of a two-dimensional image field. In this case, the integrated superpixel rotatably suspended from the two mutually orthogonal axes has at least five sensor elements 11 each having a pixel sensor 14 and a filter structure 12 with at least one structured metal layer which, in response to electromagnetic radiation of a wavelength range, has a higher transmission through the filter structure to the pixel sensor 14 as wavelengths surrounding the wavelength range. Each sensor element 11 of the superpixel is assigned a different wavelength range and the sensor elements 11 are integrated together on a semiconductor substrate 16. With a servomotor, the superpixel could be pivoted about its orthogonal axes of rotation. Furthermore, such a multispectral image sensor comprises a device for imaging the point from the two-dimensional image field onto the superpixel, for example in the form of an optical system (for example a lens). In the servo motor, means for causing a dot imaged on the superpixel to pass through the two-dimensional image field can be seen. In the same way, the superpixel could also be moved rigidly through a kind of scanning process (eg, line by line) over the two-dimensional image field in order to scan spectral information of the image field. Having described possible applications of a one-dimensional multispectral-line detector with reference to FIGS. 2a-d, two-dimensionally arranged multispectral sensors will be discussed in more detail below. For this purpose, a further exemplary embodiment of a multispectral image sensor 30 in FIG. 3 is shown schematically.

With a matrix arrangement of sensor elements, different spectral ranges with different spectral resolution can be scanned. In the example of FIG. 3, the line with the sensor elements from A (I) to A (n) is intended for a spectral range A, the row with the sensor elements C (I) to C (n) is intended for spectral range C. A spectral resolution in the region of the sensor elements A (I) to A (n) is for example higher than the spectral resolution in the region of the sensor elements C (I) to C (n). In areas D and E no sensor elements are arranged. There, no measurement is made because, for example, no light hits the multispectral image sensor 30 in this area. The multispectral image sensor 30 thus offers the possibility of already defining in the design which areas should be measured with which resolution. It may be important for industrial applications where individual spectral lines or areas need to be controlled. The size of microelements of the filter structures or the photodiodes located underneath plays a similar role as the input gap in a conventional spectrometer.

A further alternative to the arrangement of the sensor elements results from the fact that a two-dimensional pixel array is constructed, wherein each pixel or superpixel itself consists of a matrix of wavelength-selective sensor elements, as shown by way of example in FIG. 4a.

As a result, for example, a camera chip can be realized whose individual pixels or superpixels are manifold may contain spectral information. Accordingly, with the arrangement shown in FIG. 4, a variety of multi-spectral images can be provided which contain many times more information than a standard camera chip with RGB sensors or Bayer mask. The arrangement 40 shown schematically in FIG. 4a can be used, for example, as an imaging fingerprint sensor which supplies the associated spectral information for each superpixel 42-1 to 42-9. Thus, for example, a green ball (made of PVC) in a green field can be easily recognized, because the spectrum of PVC differs significantly from that of chlorophyll, and even in the green spectral range has different lines. This is not possible with a conventional color sensor, because there the spectral filters used have a much too broad bandpass characteristic. In conventional color sensors can be tried only with image processing algorithms to accomplish the above-mentioned detection, but this is much more complicated than the same information in the sensor to take the relevant information.

With a multispectral image sensor 40 with a two-dimensional array of superpixels 42 according to FIG. 4 a, according to exemplary embodiments of the present invention, a three-dimensional image sensor or a distance measuring system can also be realized. 4b shows a schematic illustration of a distance measuring system 43 according to the invention for determining three-dimensional images with a multispectral image sensor 40 having a two-dimensional array of superpixels 42 according to FIG. 4a.

The distance measuring system 43 can, in addition to two-dimensional image information, determine a distance between the distance measuring system 43 and an object 44 and thus provide third image information (image depth). For this purpose, the distance measuring system 43 comprises a source or transmitting device 45 for emitting a transmission signal S in the form of electromagnetic radiation, in particular light, during a transmission time interval T _s . The broadcasting Direction 45 includes according to embodiments, a light source, for example in the form of an LED (LED = Light Emitting Diode), an IR LED (IR LED = Infra-Red LED) or a laser diode. The transmission device 45 generates the transmission signal S, for example in the form of a frequency-modulated light signal or in the form of short light pulses. For controlling the modulation of the transmission signal S, the distance measuring device may include a modulation device 46 43, which for the purpose of controlling the modulation signaling device to the transmitter ^45: can act. The modulation acting on the transmission signal S may, for example, be an amplitude modulation of the light signal S. In this case, a modulation frequency can be, for example, in a frequency range from 1 MHz to 10 GHz, depending on the measurement accuracy requirements and measurement method of the distance measuring system 43. The action takes place in such a way that the modulation device 46 outputs a modulation signal M to the transmitting device 45, wherein the modulation signal M, for example, rectangular, sinusoidal or triangular may be formed. Furthermore, the distance measuring system 43 comprises a receiving device in the form of a multispectral image sensor 40 according to the invention for receiving an image signal or received signal E, which is a component of the transmission signal S reflected on the image object 44. The reception of the received signal E takes place during a reception time interval T _E , which can be synchronized with the transmission time interval T ₃ , such that the reception and transmission time intervals Ts are either parallel in time or that the reception and transmission time intervals follow each other in time. The synchronization of the reception and transmission time intervals can be accomplished, for example, by a control device (not shown). Furthermore, the distance measuring system 43 comprises a processing device 47 for determining a 3D image of the object 44 based on an output signal of the multispectral image sensor 40. The processing device 47 is designed to determine the 3D image so that the 3D image for one or more images several of the perpixel has distance information which depends on an output signal of at least one of the sensor elements 11 of the superpixels 42 and a spectral distribution which depends on the output signal of at least a plurality of the other sensor elements 11 of the superpixels 42. Processing device 47 can thus determine, inter alia, a distance between image object 44 and distance measuring system 43 or between image object 44 and multispectral image sensor 40. The processing device 47 may include, for example, a PMD (PMD = Photonic Mixer Device). PMDs calculate a searched distance in which they perform inter alia a comparison of the phase positions of the transmission signal S with a phase angle of the reception signal E. The theory and operating principle of PMDs are described, for example, in "Solid State Time-of-Flight Range Camera" by Robert Lange and Peter Seitz, IEEE Journal of Quantum Electronics, Vol. 37, No. 3, March 2001.

Preferably, the transmission signal S is a modulated light signal in the infrared range. Accordingly, the multispectral image sensor 40 has superpixels each having at least five sensor elements, wherein at least one pixel or sensor element 11, referred to hereinafter as a demodulator sensor element, of a superpixel 42 responds to the wavelength or the wavelength range of the transmission signal S. That is, the filter structure associated with the demodulator sensor element is configured to pass the wavelength of the transmission signal S and to filter out surrounding wavelengths. In embodiments of the present invention, therefore, in a multispectral image sensor 40, at least one color channel, ie, a pixel 11 of a superpixel 42, is reserved for distance measurements, preferably in a spectral range in which a spectral measurement is not necessary (eg in a range of 850 nm to 980 nm). Within a superpixel 42 such a distance measuring channel can be realized, which provides a third dimension, ie distance, to the recorded 2D image. For the distance measurement NEN several alternative methods are used, such as by the method described in the published patent application DE 10 04 050 627 Al, by triangulation, interferometry or transit time measurement.

In order to increase the measurement accuracy, or to use other distance measuring methods, it is also possible to provide a plurality of color channels per superpixel 42 for distance measurements, in which case each of the sensor elements 11 provided for the distance measurement is tuned to a different wavelength range of different transmission signals S. Accordingly, multiple light sources with different wavelengths can be used to illuminate the image object 44.

An application example of a multispectral 3D image sensor according to the invention for distance measurement consists for example in the form of a driver assistance camera.

Fig. 4c shows schematically a section of a line of a 3D image sensor 40, wherein further lines are constructed similarly. It can be seen that each superpixel 42 has six sensor elements 11-1,..., 11-6 for six spectral channels. Three in the visible RGB range (470 μm, 520 μm, 650 μm) and three in the IR range (780 μm, 890 μm, 910 μm). For example, only every fifth superpixel 42 has two additional channels or sensor elements 11-7, 11-8 for a distance measurement. For driver assistance systems, this is sufficient to accommodate the third dimension, i. the distance to measure to the image object. After signal processing and evaluation, two 3D images, a 3D RGB image and a 3D IR image, are thus obtained. The 3D IR image can be particularly useful in fog or night.

5 shows by way of example two construction possibilities of a spectrometer with a multi-spectral sensor chip according to embodiments of the present invention. FIG. 5 (left) shows a construction of a spectrometer from an optical system 331, which collects light and transmits it to a multispectral image sensor 50 according to the invention. The receiving optics 331 may, for example, be an optical module in a conventional spectrometer, or even only a lens that focuses ambient light onto the chip 50.

A second possibility is a structure without an optical system, as shown in FIG. 5 (right). In this case, the filter structures of the multispectral chip 50 are designed so that they are angle-selective and also have a focusing effect. Then, the chip 50 receives only light of a predefined solid angle range W, as indicated in FIG. 5 (right).

After various embodiments of multispectral chips according to the invention and spectrometers constructed therefrom have been explained above, the individual elements or sensor elements of such a multispectral chip will be discussed in detail below.

For this purpose, FIG. 6 initially shows a schematic view of a sensor element 11 for filtering electromagnetic radiation of a predetermined wavelength range, a section being particularly emphasized in order to clarify the structure of the sensor element 11.

The sensor element 11 has a filter structure 12 with at least one photonic crystal or an array of photonic crystals and a pixel sensor 14, wherein the filter structure 12 and the pixel sensor 14 are integrated in a semiconductor substrate 16 according to exemplary embodiments such that the pixel sensor 14 is arranged in a field concentration area of the filter structure 12.

As already described above, the filter structure 12 is according to exemplary embodiments a photonic crystal or a periodic arrangement of a plurality of photonic crystals, wherein the filter structure 12 or each of the photonic crystals is formed from a layer stack of dielectric layers and structured metal layers, which will be described in more detail below.

At this point, it will be explained with reference to FIG. 7, which represents a plan view of FIG. 6, what is meant by a photonic crystal or an array of photonic crystals in the following.

A single photonic crystal of the filter structure 12 is designated by reference numeral 122 in FIG. 7, while the entirety of the photonic crystals is to be referred to as array 124 or periodic arrangement of photonic crystals. In this case, the array 124 of photonic crystals can again be regarded as a larger, higher-order photonic crystal.

In embodiments, the filter structure 12 with the at least one photonic crystal 122 for on a side facing away from the pixel sensor 14 120 incident electromagnetic radiation 118 spectral selection or spectral filtering and focusing e- lektromagnetischer radiation of a predefined wavelength range in the field concentration range, so that near an edge of the filter structure facing the pixel sensor 14 or near the pixel sensor 14 for the predefined wavelength range, an electromagnetic field concentration prevails, which can be detected by the pixel sensor 14. In the case of exemplary embodiments, the pixel sensor 14 is a component which can convert electromagnetic radiation into an electrical signal, for example a PN transfer sensor. In this case, a PN junction sensor means a sensor with a PN junction realized by different doping. According to Aus For example, the PN junction sensor is designed as a photodiode.

In the optical wavelength range, this means a spectral selection of a specific wavelength or a predefined wavelength range around the wavelength by the at least one photonic crystal 122, and a focusing of the light with the predetermined wavelength. Which wavelength the at least one photonic crystal 122 passes and which wavelengths are filtered out by it depends on the three-dimensional periodic structure of the at least one photonic crystal 122 or the array 124.

Thus, the sensor element 11 can be used as a bandpass filter to detect electromagnetic radiation, in particular light, in the predefined wavelength range.

The pixel sensor 14 is therefore preferably arranged in the field concentration region of the filter structure 12 or of the array 124 of photonic crystals 122. The field concentration region has a predetermined distance d from the second side of the filter structure 12, which is determined essentially by the process technology. According to embodiments, the distance d in a 0.18 μm CMOS process technology is less than 3 μm, preferably less than 2 μm.

Sensor elements based on photonic crystals can be realized with CMOS processes, such as a CMOS opto-process, without the need for additional process steps or further processing.

A method for producing an integrated sensor element on a substrate according to embodiments comprises a step of generating a pixel sensor 14 on a substrate surface of the substrate and applying a filter structure 12 with at least one photonic Crystal on the pixel sensor 14, so that the pixel sensor 14 is located in a field concentration region of the at least one photonic crystal and is completely covered by this, wherein the generating and applying are part of a CMOS process.

According to exemplary embodiments, the application of the at least one photonic crystal 122 comprises depositing a layer stack of dielectric layers and metal layers, the metal layers each having microstructures having dimensions and spacings between two adjacent microstructures which permit transmission of electromagnetic radiation of the predefined wavelength range through the allow at least one photonic crystal 122.

An intermediate product of an integrated sensor according to embodiments is shown schematically in FIG.

The integrated sensor element, which is not yet completely manufactured, shown in FIG. 8, comprises a substrate 16, in particular a semiconductor substrate, in which a pixel sensor 14 is introduced. In this case, the pixel sensor 14 is arranged in a plane 132 which comprises the field concentration region (a type of focal plane known from classical optics) of the filter structure 12 or of the array 124 of photonic crystals 122.

The unfinished optical structure in FIG. 8 has a layer stack of metallic layers 134 and dielectric layers 136. FIG. 8 merely shows by way of example four metallic layers 134-1 to 134-4 and three dielectric layers 136-1 to 136-3. Depending on the embodiment, the number of layers may differ from the example shown in FIG. 8.

In current CMOS processes, it is possible to structure the metal layers 134-1 to 134-4 in such a way that resulting microstructures or microelements are arranged periodically and have dimensions and distances that are in the order of wavelengths of a predetermined wavelength range, in particular an optical wavelength range. This makes it possible to produce three-dimensional periodic structures with properties of photonic crystals directly on a chip. As already described above, in exemplary embodiments, the individual microelements or microstructures are of the order of magnitude of a predetermined optical wavelength, so that a three-dimensional photonic crystal is produced.

According to embodiments, the pixel sensor 14 is preferably placed very close to the last metal layer 134-1 of the structure, the distance d being dependent on the manufacturing process. The distance of the field concentration area from the last metal layer 134-1 of the filter structure 12 can be adjusted by dimensions and spacings of structuring of the metal layers 134. For an integrated optical sensor element, the distance d is therefore chosen to be less than 20 μm and preferably less than 8 μm. In the case of 0.18 μm CMOS processes, the distance between the pixel sensor 14 and the filter structure 12 or the last metal layer 134-1 is less than 2 μm.

The metal layers 134-1 to 134-4 shown by way of example in FIG. 8 are suitably structured in a CMOS process in order to obtain a photonic crystal with a good optical filter effect and optionally a focussing effect, so that no additional color filter coating is required. layering is needed.

A sensor element 11 according to embodiments can thus be realized by taking advantage of the existing metallic 134 and dielectric layers 136. In embodiments, the pixel sensor 14 is the only opto-electronic device, in particular a photodiode, one integrated sensor element of a multispectral image sensor. In this case, the pixel sensor 14 overlaps laterally with the filter structure and can be controlled individually. The pixel sensor 14 is preferably completely covered by the metal layers 134 according to exemplary embodiments.

FIG. 9 a shows a schematic side view of a section of an integrated sensor element 11 with a photonic crystal 122 and a pixel sensor 14.

The photonic crystal 122 shown in FIG. 9a includes periodically arranged patterned metal layers 134-2 through 134-4 in a dielectric medium 136, such as SiO ₂

(Silica). The structured metal layers 134 have microelements 148 with micro-openings, as indicated in the side view of the integrated sensor element 11 in FIG. 9a. The geometric shape of these microelements 148 or micro-openings can be configured in many ways and depends on the desired electromagnetic properties of the photonic crystal 122. Possible, for example, circular micro-openings whose dimensions and distances from each other are of the order of a wavelength of the predetermined wavelength range. A distance 1 between adjacent patterned metal layers 134 is also on the order of the wavelength of the desired wavelength range.

According to embodiments, the patterned metal layers 134-2 to 134-4 of the sensor element 11, which is selective for a predetermined wavelength range or color, comprise microelements 148 whose pitches and dimensions are of the order of magnitude, for example, on a side facing the pixel sensor 14 of the photonic crystal 122 to effect spectral selection and concentration of the predefined wavelength range. The dimensions and spacings of the microelements 148 have, in accordance with exemplary embodiments, an order of magnitude which, in a predefined area, for example below, around which desired wavelength λ _{res of} the predefined wavelength range is located. Therefore, the microelements 148 will hereinafter also be referred to as sub-wavelength structures. For optical wavelength ranges, the sub-wavelength structures have dimensions and distances between two adjacent sub-wavelength structures 148 that are in the range of the predefined wavelength range.

10 a shows a top view of a possible embodiment of the sub-wavelength structures 148 implemented in the metal layers 134.

FIG. 10 a can be seen as a top view of a section of a structured metal layer 134 of the integrated sensor element 11. In a metal layer, sub-wavelength elements 148 are attached. In this case, FIG. 10 a shows by way of example a detail with sub-wavelength elements 148 arranged in a 3 × 3 matrix, which have a so-called split-ring resonator structure. Thus, FIG. 10a shows a top view of a possible implementation of the various metal layers 134 with metallic sub-wavelength structures 148 shown in a side view in FIG. 9a. The dimensions of the sub-wavelength structures 148 are comparable or smaller than the wavelength λ _res of the predefined wavelength range. According to exemplary embodiments, the dimensions of the sub-wavelength structures 148 are in a range of, for example, 0.3 λ _res to 3 λ * _r res.

Changing the ratio of the radii of an outer and an inner circle of a split-ring resonator 148 shown in Fig. 10a, the corresponding resonator wavelength changes. It should be emphasized that other sub-wavelength structures, such as so-called LC-Loaded-Transmission Lines, are possible, wherein it is important that a spectrally selective transmission should be achieved. Fig. IIa shows a section of an integrated sensor element 11 according to a further embodiment of the present invention.

In addition to the structured metal layers described with reference to FIG. 9a, the integrated sensor element 11 shown in FIG. 11a additionally has a metal layer 134-1 between the photonic crystal 122 formed by the layers 134-2 to 134-4 and the pixel sensor 14 has an opening 152. In this case, the pixel sensor 14 is at a distance d from the bottom metal layer 134-2 of the photonic crystal spaced. For an integrated optical sensor, the distance d is selected to be smaller than 20 μm, and preferably smaller than 8 μm. For 0.18 μm CMOS processes, the distance d between the pixel sensor 14 and the bottom metal layer 134-2 of the photonic crystal is less than 2 μm. Again, the sub-wavelength elements 148 of the various metal layers 134-2 to 134-4, just as in the embodiment shown in Fig. 9a, each placed exactly below each other. Such a three-dimensional structure structured metal layers 134-2 to 134-4 forms a photonic crystal acting as a lens. In the lowermost, that is, the closest metal layer 134-1 to the pixel sensor 14, there is an opening 152 so that the center of the opening 152 and an axis of symmetry 154 of the photonic crystal coincide. The filter structure consisting of the photonic crystal 122 and the opening 152 are thus ideally located on a common optical axis 154. This relationship is shown once again in a plan view of the sensor element 11 in FIG. 10b for illustration.

The symmetry axis 154 of the photonic crystal 122 or the sensor element 11 coincides at least approximately with the center of the opening 152. Below the

Opening 152 is located at a distance less than d an optically active surface of the pixel sensor 14, which may be a photodiode.

The above-described filter structure 12 or the at least one photonic crystal 122 has a focusing effect for a specific resonance wavelength λ _res or for a predetermined resonance wavelength range. That is, when the electromagnetic radiation impinges on the photonic crystal 122, only the resonance wavelength and the resonance wavelength range, respectively, can propagate unhindered therethrough. The focusing effect of the photonic crystal 122 forms a field concentration range in which an increased electromagnetic field concentration predominates for the resonance wavelength λ _res or the resonance wave range. Wavelengths outside the predefined wavelength range are not transmitted at all by the photonic crystal 122 or are very strongly attenuated.

If collimated light is used, the filter structure 12 may be formed with the array 124 of photonic crystals 122 such that it has no appreciable focusing effect. That the subwavelength structures 148 are dimensioned such that the field concentration range is virtually at infinity.

In the embodiments described above, the field concentration range of a photonic crystal 122 is in the vicinity of the axis of symmetry 154. If the pixel sensor 14 is arranged in the vicinity of this field concentration range or in this field concentration range, the field concentration of the resonance wavelength λ _res can be determined by the pixel sensor 14 in embodiments or the resonant wave range can be detected.

Through the metal layer 134-1 with the opening 52 between the photonic crystal 12 and the photodiode 14, an ne spectral selectivity can be increased again. This relationship is shown in FIG.

For the sake of clarity, FIG. 12 shows only a pixel sensor 14 in the form of a photodiode 14, which is arranged behind or underneath the metal layer 134-1 with the opening 152. The photonic crystal 122, which is disposed in front of and above the metal layer 134-1, is not shown for the sake of clarity.

As previously described, in embodiments, the focusing effect of the photonic crystal 122 in the vicinity of the metal layer 134-1 closest to the photodiode 14 forms a field concentration for a particular resonant wavelength λ _res , but not for others wavelengths. This means that only the electromagnetic radiation of the desired wavelength λ _res set by the three-dimensional periodic structure of the photonic crystal can strike the photodiode 14 at almost virtually loss-free, while other wavelengths are filtered out by the photonic crystal. That is, the field concentration range of the photonic crystal 122 is wavelength-dependent.

The opening 152 in the metal layer 134-1 can significantly improve the spectral separation, so that an optical coupling between the filter structure and the pixel sensor 14 is limited to a filter wavelength transmission range. In FIG. 12, three exemplary electromagnetic field distributions 160, 162, 164 for three different wavelengths in the vicinity of the photodiode 14 are shown by way of example. For the resonant wavelength λ _r s _S , which lies in the filter wavelength transmission range, the field distribution 160 is the strongest, ie the entire energy can pass through the aperture 152, while for the other wavelengths 162, 164 only a small portion pass through the photodiode 14 reached. The photonic crystal 122 in the form of the sub-wavelength structures of the upper metal layers 134-2 to 134-4 (not shown), together with the opening 152 in the lower metal layer 134-1, causes only the predetermined wavelength λ _res resp ., A predetermined wavelength range reaches the photodiode 14. For this purpose, preferably the center of the aperture 152 and the center of the sub-wavelength structures 148 of the photonic crystal on the axis of symmetry 154 of the photonic crystal 122 is. In other words, the center of the aperture 152 and the center of the sub-wavelength structures 148 are located of the photonic crystal 122 so that the sub-wavelength structures and the aperture 152 have a common optical axis 154. In order to achieve resonance for other spectral regions, another suitable shape must be selected for the sub-wavelength structures and possibly the aperture 152. According to embodiments, the opening 152 has a diameter of approximately 1 μm.

At this point, it should be mentioned once again that the metal layer 134-1 with the opening 152 is not absolutely necessary in order to produce a sensor element according to exemplary embodiments. However, preferred embodiments include the bottom metal layer 134-1 with the opening 152 because it can improve the spectral selectivity of the device.

Another way of layering the patterned metal layers 134 is to form a periodic structure of the same or different microelements 148, rather than the hole opening 152 of the bottom metal layer 134-1, as in the overlying metal layers 134-2 through 134-4. however, the microelements of the lowest metal layer 134-1 are laterally displaced from those of the overlying metal layers (broken symmetry). As previously mentioned, the microelements 148 can take a variety of forms. Thus, for example, the described so-called split-ring resonators are possible. Other forms are also conceivable. The microelements 148 have their own filtering effect, which strongly influences a transmission of electromagnetic radiation of the photonic crystal. By CMOS processes not only two-dimensional, ie planar, but also three-dimensional sub-wavelength elements 148 can be generated. 13 shows schematically an example.

13 shows three structured metal layers 174-2 to 174-4 with planar structures 170 and vertical through-connections 172 between the structured metal layers 174. Here, the individual sub-wavelength elements thus comprise planar structures 170 and vertical structures 172 which together form three-dimensional sub-wavelength elements. The vias 172 are available in the context of conventional CMOS processes. These three-dimensional structures allow more optimization possibilities in terms of spectral selectivity and focusing of electromagnetic radiation than two-dimensional, i. planar structures.

By way of example only, the construction of sensor elements 11 has been described above with reference to a section with only one photonic crystal 122. The dimensions of the array 124 of photonic crystals 122 are selected in embodiments such that the filter structure 12 or the array 124 of photonic crystals 122 completely covers a surface of the pixel sensor 14 facing it or the filter structure 12. For this purpose, an array 124 of a plurality of identical, that is set to the same wavelength λ _res , photonic crystals 122 placed in a plane above a photodiode to completely cover a photodiode. A single photonic crystal 122 may be used as an array in this arrangement. element or photonic sub-crystal can be considered. In the case of a bottom metal layer with openings 152, the openings 152 and the respective centers of the sub-wavelength structures of the array elements lie on a common optical axis of symmetry 154 of the array elements, as already described above.

By means of the sensor elements 11 integrated in the above-described embodiments, it is possible to construct integrated multispectral image sensors or integrated spectrometers according to embodiments. If, for example, integrated sensor elements, which are each selective for different wavelengths or wavelength ranges, are arranged next to one another in a plane, then an integrated multispectral image sensor can be constructed.

For a multispectral image sensor, for example, a plurality of integrated sensor elements can be used for a pixel, wherein a first is designed to respond to a first wavelength range, a second is designed to respond to a second wavelength range, etc. That is, an integrated multispectral Image sensor according to embodiments comprises a plurality of integrated components with filter structures with at least one photonic crystal and pixel sensors or photodiodes, as described above, wherein the filter structures of different ones of the plurality of integrated components are designed to be different in response to electromagnetic radiation Wavelength regions respectively on a side of the filter structure facing the corresponding pixel sensor to generate an electromagnetic field concentration in the vicinity of the respective pixel sensor, for which the respective pix Elsensor is sensitive.

Exemplary embodiments of integrated multispectral image sensors with a plurality of integrated sensor elements are shown by way of example in FIGS. 9b and 11b. FIG. 9b shows by way of example a side view of three adjacently integrated sensor elements 11-1 to 11-3, each of which has a structure per se, as has already been described above with reference to FIG. 9a. It should be noted in the case of the multispectral image sensor 80 shown in FIG. 9b that the microelements 148-1 to 148-3 of the photonic crystals 122-1 to 122-3 of the three neighboring sensor elements 11-1 to 11-3 are each exposed to light. Different wavelengths or different wavelength ranges can be set.

FIG. IIb shows by way of example an integrated multispectral image sensor 90 with three adjacently integrated sensor elements 11-1 to 11-3, as already described in detail with reference to FIG. IIa. Again, the microelements 148-1 through 148-3 of the photonic crystals 122-1 through 122-3 of the respective ones are formed to pass respective different wavelengths to the respective photodiodes 14.

After having discussed in detail above sensor elements with filter structures designed as photonic crystals, the following describes exemplary embodiments of sensor elements of a multispectral image sensor according to the invention with zone plate metal layer structures.

14 shows a schematic side view of an integrated sensor element 11 for filtering electromagnetic radiation of a predetermined wavelength range according to a further exemplary embodiment.

The integrated sensor element 11 has a filter structure 12 made of a structured metal layer with a zone plate structure 214 and a pixel sensor 14, the filter structure 12 and the pixel sensor 14 being integrated in a semiconductor substrate 16 such that the pixel sensor 14 is arranged in a field concentration region of the filter structure 12.

The filter structure 12 has a sub-lambda zone plate structure 214 in which concentric rings define a zone plate. However, as shown in dashed lines, the zone plate structure 214 may also include an array of zone plates associated with the one pixel sensor 14 '. Although only a 3x3 array of zone plates is shown here, other ratios are possible. In particular, it is possible for the pixel sensor 14 'to be larger or smaller than the extent of the array. The following description focuses primarily on the isolated viewing of a zone plate, but the considerations are then also applicable to the case of an array of zone plates, by transferring the corresponding measures to all zone plates 214a-214i. The dimension of the individual transmissive and non-transmissive zones of the zone plates may vary, however, for example, at least one transmitting zone of any order having a zone width less than the desired pass wavelength λ (lambda) of the zoned plate structure filter, such as e.g. less than 2μm or even 1.2μm. Further, an exemplary structure will be explained with reference to FIG. 16.

The different zones of a zone plate differ in their transparency. In one case, the electromagnetic radiation is diffracted at the annular gaps and amplified by constructive interference in wavelength-specific field concentration ranges. Depending on the wavelength λ _res or for which predefined wavelength range the integrated sensor element 11 should be sensitive, the pixel sensor 14 is arranged at different distances from the structured metal layer with zone plate structure 214. The distance of the pixel sensor 14 from the zone plate 214 is determined by the field concentration range of the zone plate for the above-described agreed wavelength λ _res set. A zone plate with a binary graduation, ie completely transparent alternating with totally non-transparent, as shown schematically in FIG. 14, has many focal points for different wavelengths in each case.

In exemplary embodiments, the zone plate structure 214 for electromagnetic radiation 118 arriving on a side of the metal layer facing away from the pixel sensor 14 effects spectral selection or spectral filtering and focusing of electromagnetic radiation of a predefined wavelength range in the field concentration range, so that near a side facing the pixel sensor 14 Near the pixel sensor 14 for the predefined wavelength range, an electromagnetic field concentration prevails in the field concentration range which can be detected by the pixel sensor 14.

In the optical wavelength range, this means a spectral selection of a specific wavelength or of a predefined wavelength range around the wavelength by the zone plate 214, and a focusing of the light with the predetermined wavelength λ _res in the field concentration range. Which wavelength the zone plate in the field concentration region in which the pixel sensor 14 is arranged is focused and which wavelengths are filtered out by it depends on the structure of the zone plate 214 and the distance of the pixel sensor 14 from the zone plate.

Thus, the pixel sensor 14 is preferably disposed in the focus area of the zone plate 214 for the predetermined wavelength range. The field concentration region has a predetermined distance d from the zone plate 214 which, according to exemplary embodiments, is smaller than the wavelength λ _res to be selected or a wavelength of the predetermined wavelength range. According to embodiments, the distance d is smaller than 20 μm or 6-10 μm. Integrated sensor elements based on structured metal layers with a zone plate structure can be realized with CMOS processes, such as a CMOS opto process, without the need for additional process steps or further processing.

A method for producing an integrated sensor element 11 on a substrate according to exemplary embodiments comprises a step of generating a pixel sensor 14 on a substrate surface of the substrate and applying a filter structure 12 having at least one structured metal layer with zone plate structure 214 to the pixel sensor 14, such that the filter structure 12 and the pixel sensor 14 are integrated in the semiconductor substrate such that the pixel sensor 14 is disposed in a field concentration region of the filter structure (s), the generating and depositing being part of a CMOS process.

According to exemplary embodiments, the application of the filter structure 12 comprises the application of at least one structured metal layer, the at least one structured metal layer having microstructures in the form of zone plates 214 whose dimensions and radii between two adjacent zones, focusing the electromagnetic radiation of a predetermined wavelength λ _res or a predetermined wavelength range in the focus area.

An intermediate product of a CMOS manufacturing process of an integrated component according to exemplary embodiments has already been described schematically with reference to FIG. 8.

In all four metallic layers 134-1 to 134-4, for example, lateral registration zone plate structures can be formed. Alternatively, the metal layer 134-1 closest to the pixel sensor 14 may have an opening functioning as a diaphragm, as explained below in which case this aperture, the pixel sensor 14 or a location therebetween is vertically centered in the field concentration range.

In an integrated sensor element according to an alternative embodiment of the present invention, the metal layers 134-1 through 134-3 may be replaced by dielectrics such that only the overlying layer 134-4 forms the zone plate structure.

The respective lowest metal layer is arranged at a distance d from the pixel sensor 14, the distance d indicating at least approximately the "focal length" of a focusing zone plate in the overlying structured metal layer (s) for a particular wavelength.

Between the pixel sensor 14 and the structured metal layer 134-1 is the substrate 16 or a dielectric in the form of, for example, at least one dielectric layer.

The metal layers 134 are now patterned according to embodiments in such a way that they have a good optical filter effect with simultaneous focusing effect, without an additional color filter coating for the integrated component is necessary.

FIG. 15 a shows a schematic side view of a CMOS-integrated sensor element 11 according to an embodiment of the present invention.

The integrated sensor element 11 has a structured metal layer 134 with a zone plate structure. The zone plate 214 of the patterned metal layer 134 is divided into transparent zones 234 and non-transparent zones 236. The transparent zones 234 are formed, for example, by a dielectric 136 which lies between the structured metal layer 134 and the pixel sensor 14 is arranged. The zone plate 214 of the patterned metal layer 134 has concentric rings formed of the transparent and non-transparent zones of sub-lambda zone width and having a common center through which, perpendicular to the patterned metal layer 134, an axis of rotation 240 of FIG integrated sensor element 11 extends. The pixel sensor 14 is arranged at a distance d from the patterned metal layer 134 so that the pixel sensor is located in, or at the zone plate 214 of the patterned metal layer 134 least λ _res for a predefined wavelength or a predetermined wavelength range in the vicinity of the field concentration range point 14 , The metal layer 134 may be made of metals used in the CMOS process, such as aluminum. The dielectric layer 136 may include, for example, silicon dioxide (SiO _Σ ).

FIG. 15b schematically shows a side view of an integrated sensor element 11 according to a further exemplary embodiment of the present invention.

The integrated sensor element 11 has, in the vicinity of the pixel sensor 14, a further metal layer 252 with an opening 254. In this case, the opening according to embodiments can be configured circular. By means of this additional metal layer 252, the spectral separation of the integrated sensor element shown in FIG. 15a can be further improved. It should be noted that the additional metal layer 252 with the opening 254 is not absolutely necessary, wherein the layer 252 is, for example, the metal layer nearest or spaced from the pixel sensor.

The distance d between the pixel sensor 14 and the uppermost metal layer of the integrated sensor element lies in an order of magnitude of the desired resonant wavelength λ _res . For the optical spectral range and a 0.18 μm CMOS process, the distance d is in the range of approximately 2 microns. The zone plate 214 of the patterned metal layer thus becomes preferably realized with a very short focal length. With modern CMOS processes, however, one can achieve very fine zones and thus very short focal lengths, so that the pixel sensor 14 can be placed in the field concentration region of the zone plate 214.

The radii for each zone in the upper metal layer and the diameter of the opening 254 of the lower metal layer 252 are preferably selected such that only a specific wavelength, ie the resonance wavelength λ _res or a specific wavelength range propagate until the beginning of the pixel sensor 14 can.

16 shows an example of a sub-lambda zone plate 214, which merely exemplarily comprises three transparent circular rings, namely first, second and third order from the inside, and four non-transparent metal circular rings. Zone plates usually have 20 or more zones in practice. For the sake of clarity, only the first three zones are shown here.

The zone plate 214 of the metal layer 134 has a foaming effect. With a corresponding ratio of the radii of the transparent zones 234 and the non-transparent zones 236 at a certain distance from the zone plate 214, a concentration of the incident electromagnetic radiation similar to a focal point arises for a certain wavelength. A photodiode placed at or at least near this point can now be covered by the opened metal layer 252 such that only the electromagnetic radiation or the light of the desired wavelength strikes the photodiode 14 at least approximately loss-free, while other wavelengths are filtered out. The metal layer 252 with the opening 254 significantly improves the spectral separation. In the case of the exemplified sub-lambda zone plate, the zone width of the transparent zones 234 decreases with increasing ordinal number or with increasing distance from the center. The same applies within the non-transparent zones in between. In addition, according to the example of FIG. 16, the zone width of at least one of the transparent zones 234 is smaller than the desired pass wavelength, such as 2 μm or 1.2 μm, such as the 2nd to the last order.

As already mentioned, the field concentration range resulting from the zone plate 214 for the transmission wavelength can, for example, be up to 20 μm away from the zone plate. In the case of collimated illumination with the transmission wavelength, in this region, for example, 90% of the transmitted power, which corresponds to 50% of the incoming power or less, for example, has a lateral extent which is, for example, less than a half lateral extent of the zone plate measured at the outermost edge of the highest order transparent zone.

FIG. 17 shows an illustrative example of three field distributions 260, 262, 264 for three different wavelengths in the vicinity of the pixel sensor 14.

From FIG. 17, it can be seen that the electromagnetic field concentration 260 is highest for a resonance wavelength λ _res in the vicinity of the corresponding field concentration range of the zone plate 214. This means that for the resonant wavelength λ _res the entire electromagnetic energy or a large part thereof can be detected by the pixel sensor 14, in particular a photodiode, while for other wavelengths the corresponding electromagnetic field concentrations 262, 264 are smaller, ie only one small proportion of the respective electromagnetic radiation reaches a PN junction of the photodiode 14. If- Although the metal plate 252 provided with the opening additionally increases the spectral selectivity, the above applies equally to embodiments without the metal layer 252. Due to the increased spectral selectivity in the combination of zone plate 214 and an opening 254 of the metal layer lying directly in front of the photodiode 14 252 will be seen therein a preferred embodiment of the present invention.

A further embodiment of an integrated sensor element for a multispectral image sensor according to the invention is shown in FIG.

FIG. 18 shows an integrated sensor element 270, which has a second zone plate 1 laterally offset in a second structured metal layer 272 at a distance a from the zone plate 214 of the structured metal layer 134.

The function of the structure shown in FIG. 18 is similar to the structures described with reference to FIGS. 15b and 17. The structured metal layers 134 and 272 with zonal plate structure have a lateral offset by the distance 1 in order to be able to achieve a better spectral separation. In this case, the lateral offset 1 between the zone plate structures of the different metal layers is on the order of 2 times the desired wavelength λ _res or the desired wavelength range.

Another way of spectral separation is to slightly differentiate the ratio of the radii of the zones of layers 134 and 272. In this case, the metal layer 134 has a diffractive and focusing effect, and the metal layer 272 has an additional filtering effect, which allows only the desired resonant wavelength λ _{res to} pass. Furthermore, a combination of the above possibilities is possible, namely the lateral offset of vertically spaced zone plate structures while changing their zone radii.

After detailed descriptions have been given in the preceding structure and mode of operation of integrated sensor elements according to exemplary embodiments, the following will also discuss integrated multispectral image sensors on the basis of the integrated sensor elements with zone plate structures.

19 shows a schematic side view of an integrated multispectral image sensor or spectrometer 280 based on CMOS, which has a plurality of common sensor elements 11 integrated on a substrate.

In FIG. 19, by way of example only, three sensor elements 11 that are integrated adjacent to one another are shown, each of the three sensor elements being tuned to a different wavelength range or a different resonant wavelength λ _res . For example, the left sensor element 11-1 could be set to a wavelength from a first spectral range, the middle sensor element 11-2 to a wavelength from a second spectral range and the right sensor element 11-3 to a wavelength from a third spectral range. The zone plate array 214-1, 214-2, 214-3 of the structured metal layer 134 is here tuned to the respective spectral ranges or wavelengths. The same applies to the openings 254-1, 254-2, 254-3.

As has already been explained above, a sensor element can be adjusted to a predetermined resonant frequency λ _res , for example by adapting the respective zone plate or the radii of the different zones. In the exemplary embodiment shown in FIG. 19, the structures of the zone plates 214 - 1, 214 - 2 and 214 - 3 of the adjacent sensor elements thus have different radii transparent and not transparent rings. Furthermore, the spacings and dimensions of the hole openings 254-1, 254-2 and 254-3 could vary. The metal layer 252 with the hole openings 254-1, 254-2, 254-3 can in a color sensor thus in different planes corresponding to the distances of the hole openings 254-1, 254-2 and 254-3 to the zone plates 214-1, 214-2 and 214-3.

According to a further embodiment, the metal layer 252 could also be omitted, as already described above.

At this point, the case will be considered that the pixel sensor 14 is larger in size than a single zone plate 214. In this case, the metal layers are array-shaped, as shown in the schematic plan view in Fig. 20a ,

FIG. 20 a shows the plan view of an array-shaped metal layer 134 which has 2 × 3 identical zone plate structures 214. A pixel sensor 14 below the structured metal layer 134 is larger than a single microelement (with a zone plate) of the structure and is completely covered by the metal layer or the entire structure. That is, to fully cover a pixel sensor 14, an integrated sensor element according to embodiments may also include a plurality of identical zone plate structures 214.

FIG. 20b shows the cross section and the side view AA of the sensor element shown in plan view in FIG. 20a. In this example, the filtering function is accomplished by a combination of zone plates 214 and apertures 254 previously described. The individual zone plates 214 of the zone plate array of the upper metal layer 134 are exactly centered with respect to the openings 254 of the lower metal layer 252, which is indicated by the symmetry axes 240 in FIG. 20b. As in the previous As has already been described, instead of the openings 254 shown in FIG. 20b, the second structured metal layer 284 could also have a second zone plate array offset by 1 laterally.

After discussing sensor elements with zone plate structures in detail above, embodiments of sensor elements of a multispectral image sensor according to the invention having metal layer structures which permit the plasmon-polariton resonance effect are described below.

For this purpose, FIG. 21 shows an integrated sensor element 11 for electromagnetic radiation 118 with a pixel sensor 14 and a structured metal layer 134, a section being particularly emphasized in order to clarify the structure of the integrated sensor element 11.

The metal layer 134 is patterned to enable a plasmon-polariton resonance effect in response to electromagnetic radiation 118 of a predetermined pass-wavelength region or a predetermined resonant wavelength λ _res . According to embodiments, the pixel sensor 14 and the structured metal layer 134 are integrated together on a substrate, in particular a semiconductor substrate, so that a higher transmission through the metal layer 134 to the pixel sensor 14 results due to the plasmon-polariton resonance effect for the transmission wavelength range wavelengths surrounding the transmission wavelength range.

According to embodiments, the metal layer 134 has a sub-wavelength dimension opening 318. In order for the impinging electromagnetic radiation 118 to cause surface plasmons, the sub-wavelength aperture 318 is surrounded around the aperture by rotationally symmetric periodically arranged grooves 320 according to embodiments. With suitable dimensioning of the opening 318 and the RiI- The resonator 320 may cause a resonant interaction of the electromagnetic radiation and the surface plasmons of the patterned metal layer 134 to the previously mentioned enhanced extraordinary transmission in the predetermined wavelength range.

When the electromagnetic radiation 118 strikes the first side of the structured metal layer 134 facing away from the pixel sensor 14, electromagnetic radiation of the predetermined wavelength range directed from the sub-wavelength opening 318 beyond the second side of the structured metal layer 134 facing the pixel sensor 14 propagates. the resonance wavelength λ _res out.

It should be noted at this point that the integrated sensor element 11 shown schematically in FIG. 21 can only be an element of a larger sensor structure having a plurality of integrated sensor elements, as will be described later on with reference to FIG. 31 ,

Furthermore, non-rotationally symmetric surface structures of the metal layer 134 are also conceivable, which can cause the plasmon-polariton resonance effect, such as a slot-shaped opening with grooves arranged parallel thereto or a matrix-like arrangement of sub-wavelength openings, as shown in FIG.

Integrated sensors or sensor elements for electromagnetic radiation according to embodiments can be realized with CMOS processes, such as a CMOS opto process, without additional process steps or further processing is required.

A method for producing an integrated sensor element on a substrate comprises according to embodiments a step of generating a photodiode on a substrate surface of the substrate and depositing a metal layer which is patterned to allow a plasmon-polariton resonance effect in response to electromagnetic radiation of a predetermined wavelength range, the generating and the Applying parts of a CMOS process are. In this case, the photodiode and the metal layer are integrated together on the semiconductor substrate, that due to the plasmon-polariton resonance effect on the photodiode an electromagnetic field concentration can form, for which the photodiode is sensitive.

According to exemplary embodiments, the application of the metal layer comprises a structuring of the metal layer with an opening 318 with a sub-wavelength dimension, wherein the opening is surrounded by rotationally symmetrical periodically arranged grooves around the opening 318. In this case, the grooves around the opening have dimensions and spacings which are suitable for producing the plasmon-polariton resonance effect for the predetermined wavelength range in the structured metal layer 134.

According to a further embodiment, the application of the metal layer comprises a structuring of a slot-shaped opening in the metal layer, which has a width smaller than a wavelength (resonance wavelength λ _res ) of the predetermined wavelength range, and a structuring of at least approximately parallel to the slot-shaped opening grooves in the metal layer 134, wherein the dimensions of the grooves are suitable for effecting the plasmon-polariton resonance effect for the predetermined wavelength range in the patterned metal layer.

A structuring of the metal layer with sub-wavelength openings 318 arranged in matrix form in a lattice network is likewise conceivable, as shown schematically in FIG. 30 is shown. It should be noted that a shape of the sub-wavelength openings can generally be chosen arbitrarily.

An intermediate product of a CMOS manufacturing process of an integrated sensor element according to embodiments has been described schematically with reference to FIG.

A photosensitive surface of the photodiode 14 has a distance d from that of the photodiode to the closest metal layer 134-1, the distance d being determined essentially by the manufacturing process and being less than 20 μm and preferably less than 8 μm. For 0.18 μm CMOS processes, the distance between the photodiode 14 and the metal layer 134-1 is less than 2 μm.

In the case of integrated sensor elements with a structured metal layer according to exemplary embodiments, therefore, only the lowermost metal layer 134-1 closest to the pixel sensor 14 or the photodiode will remain. The overlying layers are not even applied or removed again for the production of the integrated sensor after its application. The metal layer 134-1 can be patterned by etching, for example.

A structured according to an embodiment metal layer with underlying photodiode is shown schematically in a side or sectional view in Fig. 22.

The structured metal layer 134-1 illustrated in FIG. 22 is surrounded by a dielectric 136 and has by way of example two structural elements 340, which are identified by the curly brackets in FIG. A structural element 340 in each case has a sub-wavelength opening 318, which may, for example, be circular or linear. In a circular or rotationally symmetrical sub-wavelength opening 318, the grooves surrounding the opening 18 are recesses 342 and elevations 344 also rotationalssyπunetrisch arranged. In the case of a linear or slot-shaped sub-wavelength opening 318, the depressions 342 and elevations 344 are arranged parallel to the linear elevation 318.

As a result of the sub-wavelength openings 318, light of a predefined wavelength λ _{res can be} selected by the plasma-polariton resonance effect and then hit the pixel sensor 14.

FIG. 23 shows a single element or a structural element 340 of the array-shaped structure shown in FIG. 22 in the metal layer 134-1.

The structural element 340 shown in FIG. 23 may be rotationally symmetric with respect to the sub-wavelength opening 318 in the center, as shown in the perspective view in FIG. 24 for better illustration. In other embodiments, the structural member 340 may have a stripe-like or line-like structure as shown in FIG. 25 for better illustration. A top view of the structure element 340 with strip-shaped or line-like opening 318 and structure shown in FIG. 25 is also shown in FIG. 29.

A structural element 340 according to exemplary embodiments comprises a region of the metal layer 134-1, which has a periodically structured upper area of the period A with indentations 342 and elevations 344 and a sub-wavelength opening 318 which lies in the center of the structure 340. For a predetermined resonance wavelength λ s _re of 118 corresponds to the structural ^¬ tur 340 incident electromagnetic radiation is of the plasmon-polariton resonance effect. This effect causes for the resonance wavelength λ _res through the sub-wavelength opening 318, for example, more than 15% of the incident electromagnetic radiation, although an area ratio of the opening 318 to the area of the entire member 340 is very small. For other wavelengths than the resonance wavelength λ _res , on the other hand, there is no resonance and thus almost no transmission of electromagnetic radiation of the other wavelengths through the opening 318. This means that the transmission for a predetermined wavelength λ _res through the structural element 340 is dependent on the area ratio of the area the opening 318 depends on the area of the entire element 340, as well as the period A of the structured surface or the elevations 344 and recesses 342.

The period A which allows the highest transmission depends inter alia on the thickness (t + h) of the structured metal layer 134-1. For example, for a resonant wavelength λ _res of 650 nm, the width or diameter b of the opening 318 could be selected to 110 nm, the area ratio of the area of the opening 318 to the area of the entire element 340 could be 0.01, and A could be 90 nm and t are chosen to be 20 nm. At this point, it should be emphasized that these values represent only example values to give an idea of possible magnitudes. According to embodiments, A is in a range of 10 nm to 2110 nm. The thickness (t + h) of the metal layer 134-1 in embodiments is in a range of 30 nm to 2500 nm, preferably in a range of 350 nm to 550 nm. The height h of the depression is, of course, smaller than the thickness (t + h) of the metal layer ^A 134-l and in embodiments lies in a range above (t + h) / 2. The area ratio of the area of the opening 318 to the area of the entire element 340 is less than 0.3 in embodiments.

A side view of another embodiment of a structural element 340 is shown in FIG. It shows one

Possibility to create the grooves of the structure element, which can also be implemented, for example, in CMOS processes is, for which an example has been shown in Fig. 8 by way of example.

32 shows a structural element or a metal structure 340, which comprises a first structured metal layer 134-1 and a second structured metal layer 134-2 with an interposed dielectric 136-1, through which in turn metallic plated-through holes 352 extend. The first patterned metal layer 134-1 has a sub-wavelength aperture 318. The overlying vias 352 and the second patterned metal layer 134-2 are each patterned to form together the periodic pits 342, bumps 344, and the sub-wavelength opening 318. That At locations of recesses 342 and sub-wavelength aperture 318, both metal of the second patterned metal layer 134-2 has been removed. At locations of the bumps 344, the metal of the second patterned metal layer 134-2 has not been removed, and the vias 352 may laterally be congruent with the metal of the second metal pattern 134-2 in, for example, rings. The metal of the vias 352 may be the same or different from the metal of the metal layers 134-1 and 134-2. The dielectric 136-1 fills both the gap in the opening 318 and in the resulting grooves or recesses 342. In the manufacture, for example, the metal layer 34-1 is first applied and structured, whereupon the plated-through holes are formed at the corresponding locations. Then, for example, a first part of the dielectric is then applied in order to fill the recesses formed until then, whereupon again the second metal layer 134-2 is applied and patterned.

A corresponding structure of a structural element 340 having more than two structured metal layers and more than one via plane 136-1 is naturally also conceivable. It should also be recalled that the Of course, grooves or depressions and projections or elevations need not of course be annular but also other lateral shapes are possible, such as rectilinear courses, as shown in Fig. 25, but also others, such as rectangular.

Structured metal layers according to embodiments of the present invention can be realized within the framework of CMOS technology, for example by means of metal layers which are not completely or completely etched through. Even with changing process parameters, the structure period A can be kept constant.

FIG. 26 schematically illustrates the focusing effect or the plasmon-polariton resonance effect of the structured metal layer 134-1 according to exemplary embodiments.

The electromagnetic radiation 118 initially strikes the entire surface of the structure element 340. Due to the plasmon polaritron resonance effect, the electromagnetic radiation of the resonance wavelength λ _res or of the resonance wavelength region concentrates in the vicinity of the sub-wavelength opening 318 and passes through it. extends in the direction of the pixel sensor 14, and finally hits the pixel sensor or the photodiode 14. Here, according to embodiments, the distance d between the metal layer 134-1 and the photodiode 14 is smaller than the resonance wavelength λ _res , for example, less than 3 microns.

FIG. 27 shows a transmission ratio of three different wavelengths λi, X ₂ and λ ₃ for a ratio b / B = 0.01. The transmission power is shown logarithmically.

As can be seen from FIG. 27, λi corresponds at least approximately to the resonance wavelength λ _{tes of} the metal layer structured in accordance with exemplary embodiments. The Sub-wavelength opening 318 or its width or diameter b is preferably smaller than the resonance wavelength λ _res - B can theoretically be chosen very large, practically reduces the electromagnetic field strength for the resonance wavelength λ _res due to roughness of a surface of the patterned metal layer. With these size ratios (b / B = 0.01), the area ratio of the area of the opening 318 to the area of the entire element 340 is 1: 10,000, ie without resonance effect, the incident electromagnetic radiation 118 or the incident light is reduced by approx. 40 dB attenuated. By contrast, at the resonant wavelength λ _res , attenuation is less than 10 dB.

.Lambda..sub.i from in Fig. Transmittance shown 27 for the three wavelengths _λ Σ and λ ₃ normalized to .lambda..sub.i, can be seen that, for a use of patterned metal layers in accordance with embodiments of the present invention, a very good spectral separation between different spectral possible is. Good attenuation for unwanted spectral values with steep spectral edges is possible.

In practice, it may happen that the geometric dimensions, in particular the extent B, of a single structural element 340 are smaller than dimensions of an underlying photodiode 14. In this case, an integrated sensor element can be realized by forming a plurality of metal layers in a metal layer Structure elements 340 is arranged so that a photodiode of the structured metal layer can be completely covered. This relationship is shown by way of example in FIG. 28.

FIG. 28 shows a plan view of a structured metal layer 134 - 1 with four structural elements 340.

The four structural elements shown can be made identical according to embodiments. This means, the subwavelength openings 318 and the cylindrical structures respectively have the same dimensions. As a result, precisely one resonance wavelength λ _res or one resonance wavelength range is made possible for propagating through the plasmon-polariton resonance effect as far as the pixel sensor or the photodiode 14 lying below the metal layer 134-1.

In this case, adjacent rings have a different height. That is, the depressions 342 are lower than the elevations 344.

Having been described in detail in the foregoing structure and operation of integrated sensor elements with plasmon-polariton resonance effect according to exemplary embodiments, integrated multispectral image sensors or spectrometers based on the integrated sensor elements will be discussed below. For this purpose, FIG. 31 shows by way of example a plan view of a structured metal layer 134-1 with three structural elements 340-1 to 340-3.

The structural elements 340-1 to 340-3 shown in FIG. 31 could each be tuned to a different wavelength range or a different resonance wavelength λ _res , in which case each structural element is assigned a separate pixel sensor for detecting the respective resonance wavelength λ _res , For example, a first structure element 340-1 could be set to a wavelength of a first spectral range, a second structure element 340-2 to a wavelength of a second spectral range, and a third structure element 340-3 to a wavelength of a third spectral range, etc. The structural elements 340 of the structured metal layer are thus matched to the respective spectral ranges or wavelengths in the case of a multispectral image sensor. The same also applies to the openings 318-1 to 318-3. It should be noted that natural It would also be possible to set a plurality of adjacent structure elements 340 of a multispectral image sensor to a specific wavelength or a spectral channel, if required by the dimensions of a photodiode, as already explained above. That is, for example, an arrangement with several identical structural elements according to FIG. 28 could be provided for each spectral channel.

As already explained above, a sensor element can be adjusted to a predetermined resonant frequency λ _res , for example, by adapting the respective structural elements 340. In the exemplary embodiment shown in FIG. 31, the structural elements 340 of adjacent sensor elements can thus have different radii of the rings. Furthermore, the dimensions of the hole openings 318-1, 318-2 and 318-3 may vary.

Embodiments thus comprise an integrated multispectral image sensor with a plurality of integrated sensor elements, wherein the structured metal layers or structural elements 340 of the integrated sensor elements are designed to be higher in response to electromagnetic radiation of different transmission wavelength ranges due to the plasmon-polariton effect for the respective transmission wavelength range To allow transmission through the respective metal layer to the respective pixel sensor as wavelengths surrounding the respective transmission wavelength range.

In summary, the present invention thus comprises an integrated spectrometer whose integrated sensor elements can each be adjusted to electromagnetic radiation of different wavelength ranges, as has been described in detail above. The integrated spectrometer can be manufactured in the context of conventional CMOS processes. With the aid of exemplary embodiments of the present invention, it is possible within the scope of a CMOS process to realize a one- or two-dimensional photodiode array, so that a corresponding narrow-band filter for a specific spectral range is built up for each individual photodiode, and an effect as by gives a dispersive element (prism or grating) in spectroscopy.

Some of the foregoing embodiments used as a filter structure those which were formed as a photonic crystal or allowed a plasmon-polariton effect. As described, it is possible to produce such filter structures in a CMOS technology by using the metal layers 134. In particular, the possibility has also been pointed out that the lowermost metal layer 134-1, which is closest to the pixel sensor 14, could be used as a type of diaphragm layer, while one or more of the metal layers 134-2 to 134-4 located above are used for this purpose to form the photonic crystal or the structure permitting the plasmon-polariton effect. In addition to these exemplary embodiments, it should be noted that the distance between the metal layer closest to the pixel sensor 14, which contributes to the formation of the photonic crystal or the structure permitting the plasmon-polariton effect, for example the metal layer 134-2, to that as an aperture layer acting metal layer 134-1 is preferably less than or equal to the average transmission wavelength of the Durchlassbe- riches the transmission characteristic of the filter structure, which results from the photonic crystal or the plasmon-polariton effect enabling structure in combination with the diaphragm layer. If, for example, the center transmission wavelengths of the subpixels lie in the visible spectrum, the distance between the aforementioned metal layers, for example, can be less than or equal to 400 nm. The average pass frequency could be considered as the frequency at which the integral passes through the passband. Characteristic is 50% of the total integral. The passage width of the bandpass filters of the individual subpixels could, for example, be less than 100 nm and preferably less than 50 nm. For the sake of brevity, it should be pointed out that, depending on the circumstances between the aforementioned metal layers or the diaphragm metal layer and the pixel sensor, one or more other metal layers are present could, on the other hand, be able to comply with the maximum distances just mentioned. Namely, when these maximum distances are maintained, the diaphragm layer is located at a near field distance to the photonic crystal or the plasmon-polariton effect enabling structure, and by appropriately placing one or more apertures in the diaphragm layer at locations where the field concentration of the photonic crystal or plasmon-polariton structure at the desired pass frequency maxima, the wavelength selectivity • of the resulting filter structure relative to the condition that the aperture layer is absent can be increased.

Finally, it should be pointed out that it is not absolutely necessary that metal layers are used to define the filter structure, regardless of whether it is a photonic crystal, a zone plate optics or a plasmon-polariton structure according to the above exemplary embodiments , Rather, instead of or in addition to the structured metal layer shown there, a structured polysilicon layer can also be used. FIG. 37, like FIG. 8, shows an embodiment of a multi-spectral sensor produced in CMOS technology. As can be seen, the same layers exist as in FIG. 8 according to this CMOS technique. However, a polysilicon layer 700 is arranged between the lowermost metal layer 133-1 and the semiconductor substrate 136. According to an embodiment of the present invention, it is now also possible to form a filter element by combining the pixel sensor sensor 131 with a filter structure not only through the metal layers but is also obtained by structuring the polysilicon layer 700, that is to say in combination with a structuring of one or more of the metal layers 133-1 to 133-3. Of course, according to alternative embodiments, it would also be possible to combine a plurality of polysilicon layers, if such layers are present in the technology used. As can be seen, the polysilicon layer 700 is directly on the substrate 136. Of course there are alternatives for this. As with the metal layers, the polysilicon layer 700 could also be further from the semiconductor substrate 136, if allowed by a respective CMOS process. It would also be possible to form a filter structure by structuring only one polysilicon layer. Furthermore, instead of using polysilicon, it would also be possible to use other polycrystalline semiconductor material. The patterning of the layer 700 to obtain a suitable bandpass filter effect as shown above may be provided in the same manner and with the same dimensions and shapes as described above with respect to the metal layers. Finally, the polysilicon layer 700 may also function as the aforementioned aperture layer, for example when the bandpass wavelength is in a spectral range at which the polysilicon layer is absorbing, or when the polysilicon layer is absorbing to the frequency measurement range of the multi-spectral sensor.

Finally, it should be noted that the CMOS metal layers described above, such as the CMOS Metalll layer, in part next to the openings for forming the filter structures may have electrical connections or interconnects, the electrical connections between circuit elements (eg transistors) of the integrated image sensor produce. This also applies to the polysilicon layer just shown. Also, it may be used to form traces or components laterally spaced from the actual pixel sensors. Finally, it should be understood that the present invention is not limited to the particular components described or the illustrative procedures, as these components and methods may vary. The terms used herein are intended only to describe particular embodiments and are not intended to be limiting. When the number or indefinite articles are used in the specification and claims, they also refer to the majority of these elements unless the context as a whole clearly indicates otherwise. The same applies in the opposite direction.

Claims

claims

1. A multi-spectral image sensor (10; 20; 30; 40) fabricated using a CMOS process and having a two-dimensional array of super pixels, each super pixel being at least five

Sensor elements (11) each having

a pixel sensor (14);

a filter structure (12) having at least one patterned layer of metal or polycrystalline semiconductor material of the CMOS process which, in response to electromagnetic radiation of a wavelength range, gives a higher transmission through the filter structure to the pixel sensor (14) than wavelengths surrounding the wavelength range;

wherein the at least five sensor elements (12) are integrated together on a semiconductor substrate (16) and are designed in pairs to different wavelength ranges.

2. Multispectral image sensor according to claim 1, wherein a first filter structure (12-1) of a first sensor element (11-1) has at least one first photonic crystal (122-1) and in which a second filter structure (12-2) a second sensor element (11-2) has at least one second photonic crystal (122-2).

3. A multi-spectral image sensor according to claim 2, wherein the at least one first photonic crystal (122-1) has a focusing effect for electromagnetic radiation of a first wavelength range, so that the electromagnetic radiation of a first Wavelength range is focused in a first field concentration range, and wherein the first pixel sensor (14-1) in the first field concentration region of the first filter structure (12-1) is arranged, and wherein the at least one second photonic crystal (122-2) has a focusing Effect for electromagnetic radiation of a second wavelength range, so that the electromagnetic radiation of the second wavelength range is focused in a second field concentration range, and wherein the second pixel sensor (14-2) in the first field concentration region of the second filter structure (12-2) is arranged.

4. The multi-spectral image sensor according to claim 2, wherein the first filter structure is formed from a first array of first photonic crystals to form one of the first filter structures ) facing surface of the first pixel sensor (14-1) completely cover, and wherein the second filter structure (12-2) from a second

Array (124-2) of second photonic crystals

(122) is formed around one of the second filter structure

(12-2) facing surface of the second pixel sensor (14-2) completely cover.

5. The multi-spectral image sensor of claim 2, wherein the at least one first photonic crystal is formed from a first layer stack of dielectric layers and structured metal layers of the CMOS process in that at least one second photonic crystal (122-2) is formed from a second layer stack of dielectric layers (136) and structured metal layers (134) of the CMOS process.

6. The multi-spectral image sensor according to one of claims 2 to 5, wherein the structured layers (134) of the first layer stack comprises first microelements (148-1) whose spacings and dimensions are of the order of magnitude to effect a first spectral selection in the vicinity of the first pixel sensor (14-1) and in which the structured layers (134) of the second layer stack second microelements (148-2) whose spacings and dimensions are of the order of magnitude to effect a second spectral selection in the vicinity of the second pixel sensor (14-2).

7. A multi-spectral image sensor according to claim 6, wherein the dimensions and distances of the first microelements (148-1) are of an order of magnitude which is below a first wavelength of the first wavelength range, and wherein the dimensions and spacings of the second microelements (148 -2) have an order of magnitude which is below a second wavelength of the second wavelength range.

8. multispectral image sensor according to claim 7, wherein the magnitude of the dimensions and distances of the first micro-elements (148-1) is in ^"a range between 0.3 times and 10 times of the first wavelength, and in which the magnitude The dimensions and distances of the second microelements (148-2) are in a range between 0.3 times and 10 times the second wavelength.

9. A multi-spectral image sensor according to any one of claims 6 to 8, wherein the first and second microelements

(148) are designed as split-ring resonators.

10. The multispectral image sensor according to claim 2, wherein the structured layers of the at least one first and second photonic crystal (122-1, 122-2) are each connected to metallic plated-through holes in order to produce three-dimensional microelectrons. to obtain elements of the at least one first and second photonic crystal (122-1, 122-2).

11. A multi-spectral image sensor according to claim 1, wherein a first filter structure (12-1) has a first structured layer (134) with a first zone plate structure (214-1) with a first field concentration range, wherein the first filter structure (12-

1) and a first pixel sensor (14-1) are integrated in the semiconductor substrate (16) such that the first pixel sensor (14-1) is disposed in the first field concentration region of the first filter structure (12-1), and wherein a second filter structure (12-2) comprises a second structured layer (134) of the CMOS process having a second zone plate structure (214-

2) having a second field concentration range, wherein the second filter structure (12-2) and a second pixel sensor (14-2) are integrated in the semiconductor substrate (16), so that the second pixel sensor (14-2) in the second field concentration region of the second filter structure (12-2) is arranged.

12. The multispectral image sensor according to claim 11, wherein the first and the second zone plate structure (214-

1; 214-2) each have an effect influencing a spatial angle distribution.

13. The multispectral image sensor according to claim 11, wherein the first filter structure further comprises a first further structured layer of the CMOS process having at least approximately the same zone plate structure as the first structured layer ), wherein the at least approximately identical zone plate structures of the first structured layer (134) and the first further structured layer (272) are laterally offset from one another in order to produce a spectral filtering effect of the first sensor element (11-1), and wherein the second filter structure (12-2) further comprises a second further structured layer (272) with at least approximately identical zone plate structure (214) as the second structured layer (134), wherein the at least approximately identical zone plate structures of the second structured layer (134) and the second further structured layer (272) are laterally offset from one another in order to obtain a spectral filtering effect of the second sensor element (11-2).

14. The multispectral image sensor according to claim 11, wherein the first filter structure further comprises a first further structured layer (272) with zone plate structure, wherein the zone plate structure of the first further structured layer is 272) has different ratios of zone radii with respect to the zone plate structure of the first patterned layer (134) to obtain a first spectral filtering effect, and wherein the second filter structure (12-2) further comprises a second further patterned layer (272) of zone plate structure (214), wherein the zone plate structure (214) of the second further structured layer (272) opposite the zone plate structure of the second structured layer (134) has different ratios of zone radii to obtain a second spectral filtering effect.

A multispectral image sensor according to claim 13 or 14, wherein the first further patterned layer (272) is a metal or polycrystalline semiconductor material layer in the semiconductor substrate (16) closest to but spaced from the first pixel sensor (14-1). and wherein the second further patterned layer (272) comprises a metal layer closest to the second pixel sensor (14-2) or polycrystalline semiconductor material in the semiconductor substrate (16).

16. The multi-spectral image sensor according to claim 11, wherein radii of alternately transparent and non-transparent regions of the first zone plate structure are adapted to the first wavelength range, and radii of alternately transparent and non-transparent regions the second zone plate structure (214-2) are adapted to the second wavelength range.

17. The multispectral image sensor according to claim 11, wherein the first zone plate structure has a first array of zone plates each defining a part of the first field concentration area, and the zone plates of the first array are common to the first pixel sensor -1), and wherein the second zone plate structure (214-2) has a second array of zone plates each defining a portion of the second field concentration range, and the zone plates of the second array are common to the second pixel sensor (14-2). assigned.

18. Multispectral image sensor according to one of the preceding claims, in which a first structured layer (134-1) is arranged between a side of the first filter structure (12-1) facing the first pixel sensor (14-1) and the first pixel sensor (14-1). of the CMOS process of metal or polycrystalline semiconductor material is arranged, and in which between a second pixel sensor (14-2) facing side of the second filter structure (12-2) and the second pixel sensor (14-2), a second patterned layer (134-2) of the CMOS process is made of metal or polycrystalline semiconductor material.

19. The multispectral image sensor according to claim 18, wherein the field concentration range is wavelength-dependent, such that an optical coupling between the first filter structure and the first pixel sensor (14-1) is limited to a first filter wavelength transmission range and the first structured layer (134-1). a first aperture (152-1) disposed so as to further restrict the optical coupling from the first filter wavelength transmission region, and so that an optical coupling between the second filter structure and the second pixel sensor (14-2) is incident on one second filter wavelength transmission region is limited and the second structured layer (134-2) has a second opening (152-2) which is arranged so that the optical coupling is further restricted by the second filter wavelength transmission region.

20. The multispectral image sensor according to claim 1, wherein the at least one patterned layer (134-1) of a first filter structure (12-1) in response to electromagnetic radiation (118) of a first wavelength range allows a plasmon-polariton resonance effect, and in in that the at least one structured layer (134-1) of a second filter structure (12-1) enables a plasmon-polariton resonance effect in response to electromagnetic radiation (118) of a second wavelength range.

21. The multi-spectral image sensor of claim 20, wherein the at least one patterned layer (134-1) of the first filter structure (12-1) has a first aperture (318-1) of sub-wavelength dimension, the first aperture (318-1) of periodically arranged first grooves (342, 344) around the first opening (318-1) is surrounded, the dimensions and distances from each other, which are suitable for the first wavelength range in the at least one structured Layer (134-1) of the first filter structure (12-1) to produce the plasmon-polariton resonance effect, and in which the at least one structured layer (134-1) of the second filter structure (12-2) has a second opening (12). 318-2) of subwavelength dimension, the second opening (318-2) being surrounded by periodically arranged second grooves (342, 344) about the second opening (318-2) having dimensions and distances from each other that are suitable in order to generate the plasmon-polariton resonance effect for the second wavelength range in the at least one structured layer (134-1) of the second filter structure (12-1).

22. The multi-spectral image sensor according to claim 21, wherein the first opening (318-1) and the first grooves and the second opening (318-2) and the second grooves are each rotationally symmetric.

23. The integrated multispectral image sensor according to claim 21, wherein an area ratio of an area of the first opening to an enclosed area of a rotationally symmetric first groove around the first opening having a largest diameter is less than 0.4 and wherein an area ratio of an area of the second opening (318-2) to an enclosed area of a rotationally symmetric second groove around the second opening having a largest diameter (B) is smaller than 0.4.

24. The multispectral image sensor according to claim 21, wherein the first opening (318-1) is formed linearly and has a width (b) smaller than a wavelength of the first wavelength range, and wherein the first grooves (342, 344) at least approximately parallel extend to the first opening, and wherein the second opening (318-2) is formed linear and a width (b) smaller than a wavelength of the second wavelength range, and in which the second grooves (342, 344) extend at least approximately parallel to the second opening.

25. A multi-spectral image sensor according to claim 24, wherein a ratio of the area (b) of the line-shaped openings (318-1 / 318-2) to one of two farthest from the respective opening (318-1; 318-2) remote parallel Grooved area is less than 0.4.

26. The multispectral image sensor of claim 20, wherein the at least one patterned layer (134-1) of the first filter structure (12-1) comprises a two-dimensional periodic array of sub-wavelength apertures, and wherein the at least one patterned layer (134-1 ) of the second filter structure (12-2) has a two-dimensional periodic array of sub-wavelength apertures.

27. The multispectral image sensor according to claim 20, wherein the first pixel sensor is arranged at a distance from the at least one structured layer of the first filter structure. which is smaller than a wavelength of the first wavelength region, and wherein the second pixel sensor (14-2) is arranged at a distance (d) from the at least one patterned layer (134-1) of the second filter structure (12-1) is smaller than a wavelength of the second wavelength range.

28. The multispectral image sensor according to claim 1, wherein at least one patterned layer of a first filter structure has structures for completely covering a first pixel sensor, and at least one structured layer of a second Filter structure (12-2) Having structures to completely cover a second pixel sensor (14-1).

29. Multispectral image sensor according to one of the preceding claims, in which a first pixel sensor (14-

1) has a predetermined distance (d) from a side of a first filter structure (12-1) facing the first pixel sensor (14-1) which is smaller than 20 μm and preferably smaller than 8 μm, and in which a second pixel sensor (14-2) has a predetermined distance (d) from a side of a second filter structure (12-2) facing the second pixel sensor (14-2) which is smaller than 20 μm and preferably smaller than 8 μm.

30. A multi-spectral image sensor according to one of the preceding claims, wherein the electromagnetic radiation (118) is light.

A multi-spectral image sensor according to any one of the preceding claims, wherein said at least five pixel sensors (14-1; 14-2) are PN junction sensors.

32. A multi-spectral image sensor according to any one of the preceding claims, wherein said at least five pixel sensors (14-1; 14-2) are photodiodes.

33. A multi-spectral image sensor according to one of the preceding claims, which is manufactured in CMOS technology.

34th system, with

a multi-spectral image sensor (40) according to one of the preceding claims;

a source (45) for irradiating an object (44) with electromagnetic radiation (S) with a spectrum which at least partially overlaps with the wavelength range of the filter structure (12) of at least one of the sensor elements (11) of the superpixels (42);

processing means (47) for determining a 3D image of the object (44) based on an output of the multispectral image sensor (40).

35. The system of claim 34, wherein the processing means (47) is adapted to perform the 3D imaging of

Object (44) by means of triangulation, transit time measurement or interferometry to determine.

36. A system according to claim 34 or 35, wherein said processing means (47) is adapted to provide said 3D processing

For example, it may be determined that the 3D image for one or more of the super pixels has distance information that depends on the output signal of the at least one of the sensor elements (11) of the superpixels (42) and a spectral distribution that depends on the output signal of at least several of the other sensor elements (11) of the super pixels (42) depends.

37. Method for producing a multispectral imaging sensor by means of a CMOS process, with the following

steps:

Generating a two-dimensional array of superpixels, each superpixel passing through

Producing at least five pixel sensors (14-1) on a substrate surface of a substrate (16);

Application of filter structures (12-1) assigned to the at least five pixel sensors in each case to a structured layer of the CMOS process made of metal or polycrystalline semiconductor material. at least five pixel sensors (14-1), each responsive to electromagnetic radiation of a wavelength range, providing higher transmission through the associated filter structure to the associated pixel sensor (14-1) than wavelengths surrounding the wavelength range;

wherein the generating and applying are parts of the CMOS process.

38. Multispectral image sensor for detecting a two-dimensional image field, with

a line sensor manufactured by means of a CMOS process with a plurality of sensor elements (11) arranged in a linear manner for the spectral detection of a geometrical line, each sensor element

a pixel sensor (14) and

a filter structure (12) having at least one patterned layer of the CMOS process of metal or polycrystalline semiconductor material which, in response to electromagnetic radiation of a wavelength range associated with the sensor element, results in a higher transmission through the filter structure to the pixel sensor (14) than wavelengths surrounding the associated wavelength range .

wherein each sensor element (11) is assigned a different wavelength range and wherein the sensor elements are integrated together on a semiconductor substrate (16); and

means for mapping a line from the two-dimensional image field onto the line sensor; and means for causing a line imaged on the line sensor to traverse the two-dimensional image field.

39. The multi-spectral image sensor according to claim 38, wherein a line imaged on the line sensor is parallel to the line sensor.

The multi-spectral image sensor of claim 38 or 36, wherein the means for causing a line imaged on the line sensor to traverse the two-dimensional image field is a conveyor belt.

41. A multi-spectral image sensor according to claim 38 or 36, wherein the means for causing a line imaged on the line sensor to pass through the two-dimensional image field is an electromagnetic radiation-reflecting element suspended from an axis of rotation.

42. The multispectral image sensor of claim 41, wherein the axis of rotation of the reflective element is parallel to the line sensor.

43. A multi-spectral image sensor according to claim 41 or 39, wherein the reflective element comprises a mirror or a metal.

44. Method for capturing a two-dimensional image field, comprising the following steps:

Arranging a line sensor produced by means of a CMOS process with a plurality of sensor elements (11) arranged in a dimentional manner for the spectral detection of a geometric line, each sensor element having a pixel sensor (14) and a filter structure (12) with at least one structured one Layer of the CMOS process of metal or polycrystalline semiconductor material, which in response to electromagnetic radiation of the sensor element associated wavelength range, a higher transmission through the filter structure to the pixel sensor (14) results as for the associated wavelength range surrounding wavelengths, each sensor element (11) a associated with other wavelength range and wherein the sensor elements are integrated together on a semiconductor substrate (16);

Imaging a line from the two-dimensional image field onto the line sensor; and

Causing a line imaged on the line sensor to traverse the two-dimensional image field.

45. Multispectral image sensor for detecting a two-dimensional image field, with

a superpixel (42) produced by means of a CMOS process, having at least five sensor elements (11) for spectrally detecting a point of the two-dimensional image field, each sensor element

a pixel sensor (14) and

a filter structure (12) comprising at least one patterned layer of the CMOS process of metal or polycrystalline semiconductor material which, in response to electromagnetic radiation of a wavelength range associated with the sensor element, results in a higher transmission through the filter structure to the pixel sensor (14) than for the associated wavelength range surrounding wavelengths, wherein each sensor element (11) is assigned a different wavelength range and wherein the sensor elements are integrated together on a semiconductor substrate (16); and

means for mapping the point from the two-dimensional image field onto the superpixel; and

means for causing a dot imaged on the superpixel to traverse the two-dimensional image field.