System-on-chip camera with integrated light sensor(s) and method of producing a system-on-chip camera

The system-on-chip camera comprises a semiconductor body with an integrated circuit, a sensor substrate, sensor elements arranged in the sensor substrate according to an array of pixels, a light sensor in the sensor substrate apart from the sensor elements, and a lens or an array of lenses on a surface of incidence. Filter elements, which may especially be interference filters for red, green or blue, are arranged between the sensor elements and the surface of incidence.

BACKGROUND OF THE INVENTION

In a system on chip (SoC) all components of an electronic system or device are integrated into or onto a single chip.

U.S. Pat. No. 7,875,947 B2 discloses color filters formed of alternately stacked inorganic materials of different refractive indices like SiO2, SiON, SiN or Si.

U.S. Pat. No. 8,284,291 B2 discloses an optical lens assembly comprising a lens with a concave surface on the side of the image, the surface having at least one inflection point.

U.S. Pat. No. 8,964,062 B1 discloses a camera of a computing device with an integrated ambient light sensor in the camera module. A microprocessor analyzes data obtained from the sensor.

U.S. Pat. No. 9,232,150 B2 discloses a system for calculating an ambient light estimate using an image sensor and a matrix of grid elements each comprised of multiple adjacent pixels.

U.S. 2014/0022650 A1 discloses an optical unit comprising two lenses arranged between two substrates for use in image processing units like cameras.

U.S. 2016/0006913 A1 discloses an optical apparatus comprising a semiconductor substrate with an image sensor and an ambient light sensor and/or proximity sensor, and an optics substrate with a lens element.

SUMMARY OF THE INVENTION

The system-on-chip camera comprises a sensor substrate comprising semiconductor material, sensor elements arranged in the sensor substrate according to an array of pixels, a light sensor in the sensor substrate apart from the sensor elements, and a surface of incidence above the sensor elements and the light sensor. The sensor substrate is connected to a semiconductor body comprising an integrated circuit and is arranged between the semiconductor body and the surface of incidence. Each of the sensor elements is provided with a further component arranged between the sensor element and the surface of incidence, the further component being a filter element or a stack of further sensor elements.

In an embodiment of the system-on-chip camera, a front dielectric layer is arranged between the sensor substrate and the surface of incidence, and each of the further components is a filter element arranged in the front dielectric layer.

Each of the filter elements may especially be a band-pass filter for either red, green or blue light.

In a further embodiment, metal spacers are laterally arranged at the filter elements or further sensor elements.

In a further embodiment, a further band-pass filter for either red, green or blue light is arranged as a filter layer between the light sensor and the surface of incidence.

In a further embodiment, each of the further components is a stack of further sensor elements, the sensor element and the further sensor elements being arranged at different distances from the surface of incidence.

In a further embodiment, a lens or an array of lenses is formed by an oxide of semiconductor material arranged on the surface of incidence.

In a further embodiment, a molding material covers the lens or array of lenses, and a diffusor is formed above the light sensor by a modified region of the molding material.

A further embodiment comprises a metallization layer between the semiconductor body and the sensor substrate, a contact pad, a via hole in the semiconductor body, and a metallization in the via hole. The semiconductor body is between the metallization layer and the contact pad. The metallization in the via hole electrically connects the metallization layer and the contact pad.

A further embodiment comprises a metallization layer between the semiconductor body and the sensor substrate, an optical component above the surface of incidence and a through-substrate interconnection electrically connecting the metallization layer and the optical component.

A further embodiment comprises an optical via penetrating the semiconductor body and an optical component opposite the optical via on a side facing away from the sensor substrate. In further embodiments the light sensor is a sensor selected from the group consisting of ambient light sensor, color sensor, hyperspectral sensor with multiple pixels or bands, infrared sensor and UV sensor.

A further embodiment comprises a proximity sensor, a gesture sensor or a time-of-flight sensor including a light source.

In a further embodiment the light sensor comprises an array of light sensors serving as a further camera.

In one aspect the method of producing a system-on-chip camera comprises providing a semiconductor body with an integrated circuit, providing a sensor substrate with sensor elements, which are arranged according to an array of pixels, and with a light sensor apart from the sensor elements, fastening the sensor substrate to the semiconductor body, and forming at least one plurality of filter elements. Each plurality of filter elements is formed by arranging a filter layer on a planar surface above the sensor substrate, applying a mask on the filter layer, the mask covering areas provided for the filter elements, structuring the filter layer using the mask, and planarizing the surface.

In particular three pluralities of filter elements may be provided for the system-on-chip camera by arranging a first filter layer on the sensor substrate, applying a first mask on the first filter layer, the first mask covering areas provided for filter elements of a first type, structuring, especially etching, the first filter layer using the first mask, planarizing the surface, arranging a second filter layer on the planarized surface, applying a second mask on the second filter layer, the second mask covering areas provided for filter elements of a second type, structuring, especially etching, the second filter layer using the second mask, planarizing the surface, arranging a third filter layer on the planarized surface, applying a third mask on the third filter layer, the third mask covering areas provided for filter elements of a third type, structuring, especially etching, the third filter layer using the third mask, and planarizing the surface.

In a variant of this method, a UV IR blocking filter layer is arranged on the planarized surface after the last filter layer is etched. A further mask is applied on the UV IR blocking filter layer, the UV IR blocking filter layer is etched using the further mask, and the surface is planarized.

In a further variant of this method, a lens layer is arranged above the sensor substrate, and a transfer mask having the shape of a lens or an array of lenses, is applied on the lens layer. A lens or an array of lenses is formed by transferring the shape of the transfer mask to the lens layer.

In a further aspect the method of producing a system-on-chip camera comprises providing a semiconductor body with an integrated circuit, providing a sensor substrate with sensor elements, which are arranged according to an array of pixels, and with a light sensor apart from the sensor elements, fastening the sensor substrate to the semiconductor body, and arranging a lens or an array of lenses above the sensor substrate. The lens or array of lenses may be formed by arranging a lens layer above the sensor substrate, applying a transfer mask on the lens layer, the transfer mask having a shape of a lens or an array of lenses, and forming a lens or an array of lenses by transferring the shape of the transfer mask to the lens layer.

In a further variant of the method, a molding material is applied to cover the lens or array of lenses, and a diffusor is formed above the light sensor by modifying the molding material in a region above the light sensor.

In a further variant of the method, metal spacers are formed at the filter elements by etching trenches in the planarized surface and filling the trenches with a metal.

The following is a detailed description of embodiments of the system-on-chip camera with integrated light sensor and the method of producing a system-on-chip camera in conjunction with the appended figures.

DETAILED DESCRIPTION

FIG.1is a cross section of a system-on-chip camera with an integrated light sensor. A semiconductor body1is fastened to a sensor substrate2comprising semiconductor material, which may be of the same kind as the semiconductor material of the semiconductor body1, in particular silicon, for instance. Sensor elements3are arranged in the sensor substrate2according to an array of pixels, and at least one light sensor4is arranged in the sensor substrate2apart from the sensor elements3.FIG.1shows one light sensor4by way of example, but two or more light sensors4may be integrated. The sensor elements3may be separated from one another and from the sensor substrate2by deep trench isolations16, for instance. The light sensor4may be separated from the sensor substrate2by deep trench isolations16, for instance.

A front dielectric layer5may be present on the front side of the sensor substrate2facing away from the semiconductor body1. An intermediate dielectric layer6may be arranged between the semiconductor body1and the sensor substrate2. The intermediate dielectric layer6may comprise a layer portion that is applied to the semiconductor body1and a further layer portion that is applied to the sensor substrate2before the sensor substrate2is fastened to the semiconductor body1. The boundary between these layer portions is indicated inFIG.1by a horizontal broken line. The layer portions may serve to fasten the sensor substrate2to the semiconductor body1by bonding. A rear dielectric layer7may be present on the side of the semiconductor body1facing away from the sensor substrate2.

The intermediate dielectric layer6may include a wiring comprising structured metallization layers8and vertical interconnections9. The wiring may especially be connected to the array of sensor elements3, the light sensor4and/or components of an integrated circuit40in the semiconductor body1. Details of the integrated circuit40are not essential, and the integrated circuit40is therefore only schematically indicated inFIG.1by doped wells. The integrated circuit40may in particular be a CMOS circuit, for instance.

In the system-on-chip camera according toFIG.1, filter elements11,12,13are arranged above the sensor elements3. It may be suitable to arrange filter elements of the same type of filter on the same level above the sensor elements3. A filter layer10may be arranged above the light sensor4. The filter layer10may be a band-pass filter for either red, green or blue light. Filter elements of a first type11may be arranged in a first layer portion of the front dielectric layer5, filter elements of a second type12may be arranged in a second layer portion of the front dielectric layer5, and filter elements of a third type13may be arranged in a third layer portion of the front dielectric layer5. The filter elements of the first type11may be band-pass filters for red, the filter elements of the second type12may be band-pass filters for green, and the filter elements of the third type13may be band-pass filters for blue, for example. The order of the levels on which filter elements of the same type, especially red, green or blue filters, are arranged is arbitrary. The optional filter layer10may be on the same level with the filter elements of any of the types11,12,13. The band-pass filters may be formed by interference filters, for instance.

The number of levels on which filter elements are arranged may differ from the system-on-chip camera shown inFIG.1and may especially be larger. Further types of filters may be arranged in the system-on-chip camera, in particular filters that are provided to protect the integrated circuit from radiation.

A UV IR blocking filter14is optionally arranged above the filter elements11,12,13. The UV IR blocking filter14, which prevents ultraviolet and infrared radiation from reaching the sensor elements3, may be an interference filter comprising a sequence of layers, which are schematically indicated inFIG.1. The UV IR blocking filter14may form an entire layer, or it may be recessed above the light sensor4, as shown inFIG.1by way of example. Another type of filter may be employed instead of the UV IR blocking filter14, in particular a filter that blocks either ultraviolet radiation or infrared radiation, according to the intended application.

The light sensor4can be an ambient light sensor, a color sensor with three pixels or bands (RGB or XYZ), for instance, a hyperspectral sensor (on-chip spectrometer) with multiple pixels or bands (e.g. more than 3 and up to 256), an IR sensor above which the UV IR blocking layer14is opened or an UV sensor above which the UV IR blocking layer14is opened. Applications include any system-on-chip combining a camera with such sensors. Further to the light sensor4, the system-on-chip camera may comprise a proximity sensor, a gesture sensor or a time-of-flight sensor including a light source, especially for emitting and detecting IR radiation, and optical barriers. The light sensor4may have multiple pixels forming an array serving as a further camera.

A surface of incidence30is provided on a side of the sensor substrate2facing away from the semiconductor body1, where radiation is allowed to enter the system-on-chip camera in the direction indicated inFIG.1by the arrows pointing downwards. A lens15or an array of lenses15is applied on the surface of incidence30above the array of sensor elements3and may especially be formed in a layer of transparent or semitransparent material, which may be an oxide of the semiconductor material of the sensor substrate2, in particular SiO2, for instance. The lens15or array of lenses15may also be arranged above the light sensor4as shown inFIG.1by way of example.

Contact pads17or a redistribution layer may be arranged on the rear side of the semiconductor body1, facing away from the sensor substrate2. Solder balls18may be arranged on at least some of the contact pads17for external electric connection. A passivation46, which does not completely cover the contact pads17, may also be applied on the rear side.

A via hole19or a plurality of via holes19may be present in the semiconductor body1. An electric interconnection between a contact pad17and a metallization layer8embedded in the intermediate dielectric layer6can be formed by a metallization21, which is arranged in one of the via holes19. A dielectric interlayer20optionally insulates the semiconductor body1from the metallization21to prevent a short circuit through the semiconductor body1.

FIG.1shows optional metal spacers22, which can be arranged at lateral surfaces of the filter layer10and the filter elements11,12,13to form apertures limiting the solid angle of incidence. The metal spacers22may comprise TiN or W, for instance, and may be formed by chemical vapor deposition and subsequent etching, for instance.

FIG.1also shows an arrangement of a further optical component24. In this example, the optical component24is a vertical-cavity surface-emitting laser (VCSEL), but other optical components may be provided in similar fashion. Further contact pads25and through-substrate vias29may serve as electric connections between terminals of the optical component24and metallization layers8of the wiring. The direction of light emission from the optical component24is indicated inFIG.1by arrows pointing upwards.

The lens15or array of lenses15may be covered by a molding material36, which is sufficiently transparent or at least semitransparent for radiation within a desired range of wavelengths. An optical isolation37, which is essentially opaque for the relevant range of wavelengths, in particular for radiation emitted by the optical component24, may be formed in the molding material36to provide an aperture. A diffusor38can also be formed in the molding material36, in particular above the light sensor4, by a regional modification of the molding material36, which is known per se. Such a diffusor38helps to eliminate shifts in the characteristics of the filter layer10that are due to a dependency of the filter characteristics on the angle of incidence of the radiation.

FIG.2is a cross section according toFIG.1for a further system-on-chip camera with an integrated light sensor. The UV IR blocking filter14is recessed above the light sensor4, and a further filter48is arranged above the light sensor4. The further filter48may especially be an IR pass filter, which allows infrared radiation to reach the light sensor4, and/or a UV blocking filter, which prevents ultraviolet radiation from reaching the light sensor4. The UV IR blocking filter14and the further filter48may be arranged on the same level, or one of these filters14,48may be on a higher level than the other one.

FIG.3is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.3that are similar to corresponding elements of the embodiment according toFIG.1are designated with the same reference numerals. In the embodiment according toFIG.3, the optical component24is arranged on the rear side of the semiconductor body1. An optical via39, which may comprise a sidewall insulation47, is provided in the semiconductor body1opposite the optical component24. The sensor substrate2is recessed above the optical component24. If the optional UV IR blocking filter14is present, it is also recessed above the optical component24. Thus the direction of the radiation emitted by the optical component24can be the same as in the embodiment according toFIG.1. The emitted radiation is indicated inFIG.3by the arrows pointing upwards.

FIG.3further shows an optical confinement23for the light sensor4. The optical confinement23may be a layer surrounding the region that is located above the light sensor4and may especially be a metal layer, in particular TiN or W, for instance. The optical confinement23may be formed by etching a trench in the front dielectric layer5and optionally in the sensor substrate2, filling the trench with the metal and planarizing the surface. Such an optical confinement23may also be provided in the embodiment according toFIG.1orFIG.2.FIG.3shows the filter layer10arranged on the level of the filter elements13, by way of example. This level is higher than the level of the filter layer10in the arrangements shown inFIGS.1and2. Instead, the filter layer10can be arranged on one of the lower levels of the filter elements11or12. A UV IR blocking filter14and/or a further filter48may be arranged above the light sensor4as in the embodiments according toFIG.1or2.

FIG.4is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.4that are similar to corresponding elements of the embodiments according toFIG.1or2are designated with the same reference numerals. In the embodiment according toFIG.4, further sensor elements3′ are arranged above the sensor elements3instead of filter elements. The distances of the sensor elements3and further sensor elements3′ from the surface of incidence30vary in each of the stacks. As the depth of penetration of light into silicon depends on the wavelength, the spectral sensitivities of the sensor element3and the further sensor elements3′ of the same stack are all different from one another. A separate detection of red, green and blue light by individual sensor elements is thus feasible without using filters. The further sensor elements3′ may be provided with metal spacers22similar to the metal spacers22of the filter elements11,12,13in the embodiment according toFIG.1.

FIG.5is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.5that are similar to corresponding elements of the embodiment according toFIG.3are designated with the same reference numerals. The embodiment according toFIG.5differs from the embodiment according toFIG.3in that, instead of filter elements, further sensor elements3′ are arranged above the sensor elements3as in the embodiment according toFIG.4.

As in the system-on-chip cameras according toFIGS.1to4, further types of filters may be provided in the system-on-chip camera according toFIG.5, in particular filters protecting the integrated circuit from radiation.

FIG.6is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.6that are similar to corresponding elements of the embodiment according toFIG.1are designated with the same reference numerals. The embodiment according toFIG.6is not provided with an optical component24. It comprises an optical confinement23as described above in conjunction with the embodiment according toFIG.3and a molding material36including a diffusor38as described above in conjunction with the embodiment according toFIG.1. In the embodiment according toFIG.6, the UV IR blocking filter14extends over the light sensor4. The UV IR blocking filter14may instead be recessed as in the embodiments according toFIGS.1to5. A further filter48may be arranged above the light filter4as in the embodiment according toFIG.2.

FIG.7is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.7that are similar to corresponding elements of the embodiment according toFIG.6are designated with the same reference numerals. The embodiment according toFIG.7is not provided with a molding material. If the lens15or array of lenses15is formed in a lens layer35, portions of the lens layer35may also remain in areas that are not occupied by the lens15or array of lenses15, as shown inFIG.7. In a further embodiment the lens15or array of lenses15may only be arranged above the array of sensor elements3, but not above the light sensor4, while the other features are the same as in the embodiment according toFIG.7. In the embodiment according toFIG.7a further filter48is arranged above the light sensor4, as in the embodiments according toFIGS.2and4.

FIG.8is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.8that are similar to corresponding elements of the embodiment according toFIG.7are designated with the same reference numerals. The embodiment according toFIG.8is not provided with an optical confinement23. The lens15or array of lenses15is arranged above the array of sensor elements3, but not above the light sensor4.

FIG.9is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.9that are similar to corresponding elements of the embodiment according toFIG.8are designated with the same reference numerals. In the system-on-chip camera according toFIG.9, the UV IR blocking filter14is recessed above the light sensor4, and a further filter48is arranged above the light sensor4. The further filter48may especially be an IR pass filter, which allows infrared radiation to reach the light sensor4, and/or a UV blocking filter, which prevents ultraviolet radiation from reaching the light sensor4.

FIG.10is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.10that are similar to corresponding elements of the embodiment according toFIG.8are designated with the same reference numerals. The embodiment according toFIG.10comprises an optical confinement23as described above in conjunction with the embodiment according toFIG.3. The array of sensor elements3is provided with further sensor elements3′ as in the embodiment according toFIG.4.

FIG.11is a cross section of a further system-on-chip camera with an integrated light sensor. Elements of the embodiment according toFIG.11that are similar to corresponding elements of the embodiment according toFIG.10are designated with the same reference numerals. The embodiment according toFIG.11does not comprise a filter above the light sensor4. The optional UV IR blocking filter is recessed above the light sensor4.

Further embodiments can be derived from the variety of embodiments according toFIGS.1to11. The array of sensor elements3may be provided with filter elements11,12,13or further sensor elements3′. The molding material36with or without optical isolation37or diffusor38, the filter layer10, the UV IR blocking filter14, the further filter48, the metal spacers22, the optical confinement23, the optical component24, the vias19,29,39and the lens15or array of lenses15, in particular the lens15or array of lenses15above the light sensor4, are optional and may be combined in various ways to obtain further embodiments.

FIG.12is a top view of an arrangement of sensors. The array of sensor elements3may especially be provided with filter elements11,12,13according to the pattern shown inFIG.12. The limits between pixels are indicated with the broken vertical and horizontal lines. The different types of hatching correspond to filter elements for red, green and blue, vertical parallel lines indicating green filters. Some positions of vias19are schematically indicated by way of example. The vias19may be arranged all around and below the sensor elements and the light sensor(s)4, as schematically indicated inFIG.12by triple dots. The vias19are favorable for providing stability by bumping. The light sensor4may be a color sensor26, for instance.FIG.12shows color sensors26for red, green and blue. A light source27and/or a photosensor28may additionally be provided for various applications and purposes, including a time-of-flight sensor, for instance.

A method of producing an embodiment of the system-on-chip camera comprising interference filters will be described in the following in conjunction withFIGS.13to23, which show cross sections of intermediate products.

FIG.13shows a cross section of an arrangement of the semiconductor body1and the sensor substrate2including sensor elements3and a light sensor4. The semiconductor body1and the sensor substrate2are fastened to one another, especially bonded by the intermediate dielectric layer6. A first filter layer31, which yields filter elements of a first type11, is arranged on the sensor substrate2. A first mask41is applied on the first filter layer31and covers the areas where filter elements of the first type11are to be formed. The filter elements of the first type11may be red filters, for instance, especially interference filters forming band-pass filters for red.

FIG.14is a cross section according toFIG.13after filter elements of the first type11are formed. The first filter layer31shown inFIG.13is structured, especially etched, using the first mask41to form the filter elements of the first type11. Then the surface is planarized with a suitable material, which may be the material that is provided for the front dielectric layer5, in particular an oxide of the semiconductor material of the sensor substrate2like SiO2, for instance.

FIG.15is a cross section according toFIG.14after a first further mask49is applied on the planarized surface. The first further mask49may be a photoresist layer, for instance. It has openings50in areas adjacent to the filter elements of the first type11.

FIG.16is a cross section according toFIG.15after trenches51are etched in the planarized surface. The trenches51are etched through the openings50of the first further mask49into the front dielectric layer5. The trenches51can be formed by dry etching, for example. The first further mask49is subsequently removed.

FIG.17is a cross section according toFIG.16after the trenches51are filled with an optically shielding material, which may especially be a metal like tungsten or TiN, for instance. The trenches51can be filled by deposition, in particular chemical vapor deposition. A planar surface is obtained by subsequent chemical mechanical polishing or isotropic backetch, for example. Thus the spacers22are formed to provide apertures limiting the solid angle of incidence.

The spacers22can instead be formed as sidewall spacers before the front dielectric layer5is applied. Spacers can be formed by a conformal deposition of the material that is provided for the spacers22and subsequent anisotropic etching.

FIG.18is a cross section according toFIG.17after a second filter layer32is arranged on the planarized surface. The second filter layer32yields filter elements of a second type12. A second mask42is applied on the second filter layer32and covers the areas where filter elements of the second type12are to be formed. The filter elements of the second type12may be green filters, for instance, especially interference filters forming band-pass filters for green. In the example shown inFIG.18, the second mask42comprises a further portion above the light sensor4. Thus a suitable filter layer, which is a green filter in this example, can be formed above the light sensor4together with filter elements that are provided for the array of sensor elements3.

FIG.19is a cross section according toFIG.18after filter elements of the second type12are formed. The second filter layer32shown inFIG.18is structured, especially etched, using the second mask42to form the filter elements of the second type12. Then the surface is planarized with a suitable material, which may again be the material that is provided for the front dielectric layer5, in particular SiO2, for instance. Further metal spacers22can be applied to the filter elements of the second type12according to the above description.

FIG.20is a cross section according toFIG.19after the spacers22are formed in the layer of the filter elements of the second type12and a third filter layer33is arranged on the planarized surface. The third filter layer33yields filter elements of a third type13. A third mask43is applied on the third filter layer33and covers areas where filter elements of the third type13are to be formed. The filter elements of the third type13may be blue filters, for instance, especially interference filters forming band-pass filters for blue. The order in which the filter layers31,32,33for the different types of filter elements11,12,13are applied may differ from the example given above.

FIG.21is a cross section according toFIG.20after filter elements of the third type13are formed and the surface is planarized. The third filter layer33shown inFIG.20is structured, especially etched, using the third mask43to form the filter elements of the third type13. Then the surface is planarized with a suitable material, which may again be the material that is provided for the front dielectric layer5, in particular SiO2, for instance. Further metal spacers22can be applied to the filter elements of the third type13according to the above description.

FIG.22is a cross section according toFIG.21and further shows a UV IR blocking filter layer34, which may be arranged on the planarized surface if a UV IR blocking filter14is desired. The UV IR blocking filter layer34may comprise a sequence of layers as schematically indicated inFIG.22. The UV IR blocking filter layer34may be maintained as an entire layer, or it may be structured using a fourth mask44.

FIG.23is a cross section according toFIG.22after an optional fourth mask44is applied. The fourth mask44is used to structure the UV IR blocking filter layer34, so that the UV IR blocking filter14is produced, which may be accomplished by etching. Recesses thus formed in the UV IR blocking filter layer34are filled with suitable material, which may again be the material that is provided for the front dielectric layer5, in particular SiO2, for instance.

FIG.24is a cross section according toFIG.23after an optional lens layer35is arranged on the planarized surface. The lens layer35may especially be an oxide of the semiconductor material of the sensor substrate2, in particular SiO2, for instance. A transfer mask45is applied, which has the shape of the lens15or array of lenses15that is to be formed. The transfer mask45may be a structured and annealed resist layer, for instance. The shape of the transfer mask45is transferred to the lens layer35, in particular by etching. This technique of transferring a surface structure of an upper layer to a lower layer is known per se. The use of a lens layer and a transfer mask is only one way of producing a lens or array of lenses. The method is not restricted to this variant, and any other conventional method can be employed to produce a lens or array of lenses.

FIG.25is a cross section according toFIG.24after the lens15or array of lenses15is formed. The transfer mask45is completely removed during or after the etching process. In the example shown inFIG.25, the lens layer35has been removed from all areas outside the area occupied by the lens15or array of lenses15. Instead, portions of the lens layer35may remain in an area that is not occupied by the lens15or array of lenses15, as in the embodiments according toFIGS.7,8,9,10and11.

FIG.26is a cross section according toFIG.25after the formation of via holes in the semiconductor body1. The via hole19is provided for an electric interconnection through the semiconductor body1. An optical via39may be provided for a further optical component. It may be suitable if the sensor substrate2is recessed above the optical via39as shown inFIG.26.

FIG.27is a cross section according toFIG.26after the application of a metallization21for the electric interconnection through the semiconductor body1and the arrangement of an optical component24on the rear side of the semiconductor body1. The embodiment according toFIG.3can then be obtained by further method steps including the application of a molding material.

The described system-on-chip camera allows to enhance the integration of optical components such as filters and lenses at wafer level and especially to reduce the size of the camera. Furthermore it facilitates the integration of multiple CMOS image sensors with discrete sensors such as ambient light sensors, color sensors and/or time-of-flight sensors, for example.