SEMICONDUCTOR CHIP, MANUFACTURING METHOD FOR SEMICONDUCTOR CHIP, AND ELECTRONIC DEVICE

The present technology relates to a semiconductor chip capable of improving image quality of a captured image, a manufacturing method for the semiconductor chip, and an electronic device. The semiconductor chip of the present technology includes: a solid-state imaging element; and a cholesteric liquid crystal layer provided on a side from which light is incident with respect to the solid-state imaging element. The cholesteric liquid crystal layer is formed by cholesteric liquid crystal. The present technology can be applied to, for example, the semiconductor chip or the like included in a camera module.

TECHNICAL FIELD

The present technology relates to a semiconductor chip, a manufacturing method for the semiconductor chip, and an electronic device, and particularly relates to a semiconductor chip capable of improving image quality of a captured image, a manufacturing method for the semiconductor chip, and an electronic device.

BACKGROUND ART

As a complementary metal oxide semiconductor (CMOS) image sensor, for example, there is a stacked CMOS image sensor configured by stacking a first semiconductor substrate on which a pixel region, which includes a pixel unit performing photoelectric conversion of each pixel and disposed two-dimensionally, is formed and a second semiconductor substrate on which a logic circuit processing a pixel signal output from the pixel unit is formed.

Furthermore, there is a semiconductor chip in which a glass for protecting an on-chip lens is formed on the on-chip lens of a CMOS image sensor via a seal resin or the like (for example, refer to Patent Document 1).

CITATION LIST

Patent Document

Patent Document 1: WO 2017/094537 A

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In such a semiconductor chip, it is desired to sufficiently suppress occurrence of flare, ghost, color unevenness, and the like in a captured image and to improve image quality of the captured image.

The present technology has been made in view of such a situation, and an object of the present technology is to improve image quality of a captured image.

Solutions to Problems

According to a first aspect of the present technology, there is provided a semiconductor chip including: an imaging element; and a liquid crystal layer provided on a side from which light is incident with respect to the imaging element.

According to a second aspect of the present technology, there is provided a manufacturing method for a semiconductor chip including: forming an imaging element; and forming a liquid crystal layer on a side from which light is incident with respect to the imaging element.

According to a third aspect of the present technology, there is provided an electronic device including: a semiconductor chip including an imaging element, and a liquid crystal layer provided on a side from which light is incident with respect to the imaging element; and a signal processing circuit configured to process a signal from the semiconductor chip.

In the first aspect of the present technology, the imaging element is provided, and the liquid crystal layer is provided on a side from which light is incident with respect to the imaging element.

In the second aspect of the present technology, the imaging element is formed, and the liquid crystal layer is formed on a side from which light is incident with respect to the imaging element.

In the third aspect of the present technology, the semiconductor chip includes: the imaging element; and the liquid crystal layer provided on a side from which light is incident with respect to the imaging element, and the signal processing circuit processes a signal from the semiconductor chip.

Each of the semiconductor chip and the electronic device may be an independent device or a module incorporated in another device.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a mode for carrying out the present technology (hereinafter, referred to as an embodiment) is described. Note that the description will be made in the following order.1. First Embodiment of Semiconductor Chip2. Second Embodiment of Semiconductor Chip3. Third Embodiment of Semiconductor Chip4. Application Example to Electronic Device5. Usage Example of Semiconductor Chip6. Application Example to Endoscopic Surgery System7. Application Example to Mobile Body

Note that in the drawings referred to in the following description, the same or similar portions are denoted by the same or similar reference numerals. However, the drawings are schematic, and the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, and the like are different from the actual ones. Furthermore, the drawings may include portions having different dimensional relationships and ratios.

Furthermore, definitions of directions such as up and down in the following description are merely definitions for convenience of description, and do not limit the technical idea of the present disclosure. For example, when an object is rotated by 90° to be observed, the upper and lower sides are changed as the left and right sides, and when the object is rotated by 180°, the upper and lower sides are reversed.

1. First Embodiment of Semiconductor Chip

<Configuration Example of Camera Module>

FIG.1is a diagram illustrating a configuration example of a camera module including a first configuration example of a first embodiment of a semiconductor chip to which the present technology is applied.

In a camera module10ofFIG.1, a semiconductor chip12is provided on a support substrate11, and a lens holder13is provided so as to surround the periphery of the semiconductor chip12. The lens holder13supports a cover glass14and a lens group15such that the cover glass14is disposed above the semiconductor chip12(side on which light is incident) and the lens group15is disposed above the cover glass14. An infrared (IR) cut filter of a multilayer film is added to the cover glass14. The lens group15includes one or more (three in the example ofFIG.1) lenses.

The semiconductor chip12is a packaged solid-state imaging device, for example, a solid-state imaging device having a wafer level chip size package (WCSP) structure. In the semiconductor chip12, a cholesteric liquid crystal layer23is adhered to the upper side (side on which light is incident) of a solid-state imaging element21via the adhesive22. A glass substrate24is provided on the upper side (side on which light is incident) of the cholesteric liquid crystal layer23.

The solid-state imaging element21is a back-illumination CMOS image sensor. In the solid-state imaging element21, a wiring32is formed on the lower side (side installed on the support substrate11) of a semiconductor substrate31such as a silicon substrate, and a solder resist33is applied to a region of the lower side of the semiconductor substrate31where the wiring32is not formed. The wiring32is connected to a wiring (not illustrated) on the support substrate11, and exchanges signals with a circuit (not illustrated) outside the camera module10. The semiconductor substrate31has a pixel region in which a pixel unit including a photodiode as a photoelectric conversion unit of each pixel is disposed two-dimensionally. On the upper side of the pixel region of the semiconductor substrate31, an on-chip lens34is provided corresponding to each pixel unit.

Light incident on the camera module10is condensed by the lens group15and is incident on the cover glass14. Transmission of infrared light among the light incident on the cover glass14is suppressed by an IR cut filter added to the cover glass14. The light transmitted through the IR cut filter is incident on the semiconductor chip12. The light incident on the semiconductor chip12is incident on a photodiode (not illustrated) provided on the semiconductor substrate31via the glass substrate24, the cholesteric liquid crystal layer23, the adhesive22, and the on-chip lens34. The light incident on the photodiode is converted into an electric signal by photoelectric conversion, and thus imaging is performed. An image signal obtained as a result of the imaging is output to the outside of the camera module10via the wiring32.

<Description of Cholesteric Liquid Crystal Layer>

The cholesteric liquid crystal layer23inFIG.1will be described with reference toFIG.2andFIG.3.

FIG.2is a diagram illustrating a semiconductor chip in a case where the cholesteric liquid crystal layer23is not provided in the semiconductor chip12ofFIG.1. In this case, among the light incident on a semiconductor chip50inFIG.2, a diffracted component of the light reflected by the surface on the upper side of the pixel region of the solid-state imaging element21(hereinafter, referred to as a sensor surface) is reflected by the surface of the glass substrate24(interface between the glass substrate24and air). At this time, light (for example, light indicated by arrows61and62inFIG.2) incident on the surface of the glass substrate24at an angle equal to or larger than the critical angle α (for example, 41.5 degrees) is totally reflected and incident on the sensor surface again. As a result, flare having a ring shape or the like occurs in the captured image. By increasing the thickness of the glass substrate24, it is possible to prevent reflected light from the sensor surface from being incident on the sensor surface again, but the height of the semiconductor chip50is increased, which hinders reduction in the height of the camera module including the semiconductor chip50. Therefore, it is difficult to reduce the occurrence of flare while suppressing the increase in height of the semiconductor chip50.

On the other hand, as illustrated inFIG.3, in the semiconductor chip12provided with the cholesteric liquid crystal layer23, among the light incident on the semiconductor chip12and reflected by the sensor surface of the solid-state imaging element21, light (for example, light indicated by arrow71inFIG.3) in a range in which the incident angle on the glass substrate24is larger than an angle in the vicinity of the critical angle α and reaches an angle β larger than the critical angle α by a predetermined angle (hereinafter, referred to as a critical angle range) is reflected by the lower surface of the cholesteric liquid crystal layer23. For example, the angle β can be set such that light of which the incident angle on the glass substrate24is larger than the angle β and which is reflected from the glass substrate24is incident on a surface other than the pixel region of the solid-state imaging element21again.

Specifically, the cholesteric liquid crystal layer23is formed by cholesteric liquid crystal. The cholesteric liquid crystal has a layered structure in which a large amount of rod-shaped molecules are overlapped with each other, and the layers are integrated such that the arrangement direction of the molecules is spiral. A normal cholesteric liquid crystal has a spiral axis in the vertical direction of a substrate on which the cholesteric liquid crystal is formed, and can reflect circularly polarized light in the same direction as the spiral winding direction. Therefore, in the semiconductor chip12, by adjusting the axial direction of the spiral axis of the cholesteric liquid crystal layer23, the molecular arrangement of each layer, and the like, light in the critical angle range among the light (polarized light) reflected by the sensor surface can be reflected by the lower surface of the cholesteric liquid crystal layer23. The critical angle range is, for example, a range in which the incident angle on the glass substrate24ranges from 40 degrees to 50 degrees.

As described above, in the semiconductor chip12, since light in the critical angle range is reflected by the lower surface of the cholesteric liquid crystal layer23, this light is incident on the vicinity of the light source again. As a result, the flare generated by the light incident again can be made indistinguishable from a light source image. Furthermore, since light in the critical angle range is not transmitted through the cholesteric liquid crystal layer23, the occurrence of flare due to this light totally reflected by the glass substrate24can be prevented. Moreover, in a case where the angle β is set such that light of which the incident angle is larger than the angle β of the upper limit of the critical angle range and which is reflected from the glass substrate24is incident on a surface other than the pixel region of the solid-state imaging element21again, the occurrence of the flare due to light of which the incident angle is larger than the critical angle range and which is reflected from the glass substrate24can also be prevented.

Note that the cholesteric liquid crystal is a type of nematic liquid crystal, and similarly to a general liquid crystal, a substance existing in a state between crystal and liquid and in a state in which molecular directions are regularly aligned is used as a liquid crystal material. Examples of the liquid crystal material of the cholesteric liquid crystal include general liquid crystal materials such as a cyanobiphenyl-based liquid crystal material, a cyanophenylcyclohexane-based liquid crystal material, an ester-based liquid crystal material, an alkenyl-based liquid crystal material, a fluorine-based liquid crystal material, and a polyfluorine-based liquid crystal material.

<First Example of Manufacturing Method of First Configuration Example of First Embodiment of Semiconductor Chip>

FIG.4is a diagram for explaining a first example of a manufacturing method for the semiconductor chip12ofFIG.1.

The entire steps ofFIG.4are performed in a unit of a wafer-like semiconductor substrate31on which one or more semiconductor chips12are formed, but inFIG.4, for convenience of description, only a region of one semiconductor chip12among one or more semiconductor chips12formed from the wafer-like semiconductor substrate31is illustrated. The same applies toFIG.5to be described later.

In step S1A, the solder resist33is formed on the lower side of the wafer-like semiconductor substrate31having the pixel region, and the solid-state imaging element21, of which the on-chip lens34is formed on the upper side and on which the wiring32is not formed yet, is formed. Next, in step S2A, the adhesive22is applied to the upper side of the semiconductor substrate31.

On the other hand, in step S1B, the cholesteric liquid crystal layer23is formed on the lower side of the glass substrate24.

In step S3, the semiconductor substrate31and the cholesteric liquid crystal layer23formed in step S1B are adhered via the adhesive22applied to the semiconductor substrate31in step S2A. As a result, the cholesteric liquid crystal layer23is formed on the upper side (light incident side) of the solid-state imaging element21on which the wiring32is not yet formed.

Finally, in step S4, the semiconductor substrate31is thinned, and the wiring32is formed on the lower side (back surface side) of the semiconductor substrate31. Then, the glass substrate24is polished and division into individual pieces is performed to form the semiconductor chip12.

<Second Example of Manufacturing Method of First Configuration Example of First Embodiment of Semiconductor Chip>

FIG.5is a diagram for explaining a second example of a manufacturing method for the semiconductor chip12ofFIG.1.

Since step S31and step S32inFIG.5are similar to step S1A and step S2A inFIG.4, the description thereof will be omitted.

In step S33, the cholesteric liquid crystal layer23is formed on the adhesive22applied to the semiconductor substrate31in step S32. As a result, the cholesteric liquid crystal layer23is formed on the upper side (light incident side) of the solid-state imaging element21on which the wiring32is not yet formed.

In step S34, the glass substrate24is adhered onto the cholesteric liquid crystal layer23. Finally, in step S35, as in step S4ofFIG.4, the semiconductor substrate31is thinned, and the wiring32is formed on the lower side of the semiconductor substrate31. Then, the glass substrate24is polished and division into individual pieces is performed to form the semiconductor chip12.

<Second Configuration Example of First Embodiment of Semiconductor Chip>

FIG.6is a diagram illustrating a second configuration example of the first embodiment of the semiconductor chip to which the present technology is applied.

InFIG.6, a portion corresponding to that inFIG.1is assigned with the same reference sign and the detailed description of the portion will be omitted.

As illustrated inFIG.6, a semiconductor chip80is different from the semiconductor chip12inFIG.1in that a flat layer81is provided instead of the adhesive22, and a spacer82is provided along the outer periphery of the semiconductor chip80on the flat layer81.

Specifically, in the semiconductor chip80, the flat layer81is formed on the upper side (light incident side) of the solid-state imaging element21. Furthermore, the cholesteric liquid crystal layer23is formed on an inner side of the spacer82formed along the outer periphery of the semiconductor chip80on the flat layer81.

Note that although not illustrated, the configuration of the camera module including the semiconductor chip80is, for example, a configuration in which the semiconductor chip12of the camera module10inFIG.1is replaced with the semiconductor chip80.

<Example of Manufacturing Method of Second Configuration Example of First Embodiment of Semiconductor Chip>

FIG.7andFIG.8are diagrams for explaining an example of a manufacturing method for the semiconductor chip80ofFIG.6.

The entire steps ofFIG.7andFIG.8are performed in a unit of a wafer-like semiconductor substrate31on which one or more semiconductor chips80are formed, but inFIG.7andFIG.8, for convenience of description, only a region of one semiconductor chip80among one or more semiconductor chips80formed from the wafer-like semiconductor substrate31is illustrated.

In step S51ofFIG.7, the solder resist33is formed on the lower side of the wafer-like semiconductor substrate31having the pixel region, and the solid-state imaging element21, of which the on-chip lens34is formed on the upper side and on which the wiring32is not formed yet, is formed. Next, in step S52, the flat layer81is formed on the solid-state imaging element21on which the wiring32is not yet formed. In step S53, the spacer82is formed along the outer periphery of the semiconductor chip80on the flat layer81formed in step S52.

In step S54inFIG.8, a cholesteric liquid crystal91for forming the cholesteric liquid crystal layer23is dropped on the inner side of the spacer82on the flat layer81. In step S55, the glass substrate24is adhered onto the spacer82, and thus the cholesteric liquid crystal layer23is formed between the glass substrate24and the flat layer81. Finally, in step S56, as in step S4ofFIG.4, the semiconductor substrate31is thinned, and the wiring32is formed on the lower side of the semiconductor substrate31. Then, the glass substrate24is polished and division into individual pieces is performed to form the semiconductor chip80.

<Third Configuration Example of First Embodiment of Semiconductor Chip>

FIG.9is a diagram illustrating a third configuration example of the first embodiment of the semiconductor chip to which the present technology is applied.

InFIG.9, a portion corresponding to that inFIG.1is assigned with the same reference sign and the detailed description of the portion will be omitted.

As illustrated inFIG.9, a semiconductor chip100is different from the semiconductor chip12inFIG.1in that a light absorption layer101is formed along the outer periphery of the semiconductor chip100on the adhesive22.

Specifically, in the semiconductor chip100, the cholesteric liquid crystal layer23is formed on an inner side of the light absorption layer101formed along the outer periphery of the semiconductor chip100on the adhesive22on the upper side (light incident side) of the solid-state imaging element21. Thus, it is possible to prevent light from being reflected by the end surface of the semiconductor chip100and being incident on the sensor surface of the solid-state imaging element21. Therefore, it is possible to capture a high-quality image with less flare and ghost.

Note that although not illustrated, the configuration of the camera module including the semiconductor chip100is, for example, a configuration in which the semiconductor chip12of the camera module10inFIG.1is replaced with the semiconductor chip100.

<Fourth Configuration Example of First Embodiment of Semiconductor Chip>

FIG.10is a diagram illustrating a fourth configuration example of the first embodiment of the semiconductor chip to which the present technology is applied.

InFIG.10, a portion corresponding to that inFIG.1is assigned with the same reference sign and the detailed description of the portion will be omitted.

As illustrated inFIG.10, a semiconductor chip120is different from the semiconductor chip12inFIG.1in that an adhesive121is formed instead of the adhesive22.

Specifically, in the semiconductor chip120, the adhesive121is not applied onto the entire solid-state imaging element21, but is applied only to a partial region along the outer periphery of the semiconductor chip120. That is, the adhesive121is formed along the outer periphery of the semiconductor chip120between the semiconductor substrate31and the cholesteric liquid crystal layer23, and a space (cavity)122is formed on an inner side of the adhesive121.

Note that although not illustrated, the configuration of the camera module including the semiconductor chip120is, for example, a configuration in which the semiconductor chip12of the camera module10inFIG.1is replaced with the semiconductor chip120.

As described above, the first embodiment of the semiconductor chip to which the present technology is applied includes the solid-state imaging element21and the cholesteric liquid crystal layer23provided on the light incident side with respect to the solid-state imaging element21, and thus the image quality of the captured image can be improved.

Specifically, the lower surface of the cholesteric liquid crystal layer23reflects light in the critical angle range among the light reflected from the sensor surface of the solid-state imaging element21. Thus, light in the critical angle range is incident on the sensor surface again in the vicinity of the light source, which causes occurrence of flare, and the flare cannot be distinguished from the light source image. Therefore, the image quality of the captured image can be improved.

Furthermore, in a case where the angle3is set such that light of which the incident angle is larger than the angle3of the upper limit of the critical angle range and which is reflected from the glass substrate24is incident on a surface other than the pixel region of the solid-state imaging element21again, the occurrence of flare due to light of which the incident angle is larger than the critical angle range and which is reflected from the glass substrate24can also be prevented. As a result, the image quality of the captured image is improved.

2. Second Embodiment of Semiconductor Chip

<Configuration Example of Camera Module>

FIG.11is a diagram illustrating a configuration example of a camera module including a first configuration example of a second embodiment of the semiconductor chip to which the present technology is applied.

InFIG.11, a portion corresponding to that inFIG.1is assigned with the same reference sign and the detailed description of the portion will be omitted.

A camera module150inFIG.11is different from the camera module10inFIG.1in that a semiconductor chip160is provided instead of the semiconductor chip12. The semiconductor chip160is different from the semiconductor chip12inFIG.1in that a cholesteric liquid crystal layer171is provided instead of the cholesteric liquid crystal layer23and the glass substrate24is not provided.

The cholesteric liquid crystal layer171of the semiconductor chip160suppresses transmission of light having a wavelength around 700 nm, which is a wavelength band of a boundary between infrared light and visible light, among light incident on the semiconductor chip160via the lens group15and the cover glass14. That is, the cholesteric liquid crystal layer171reflects light having a wavelength around 700 nm.

Specifically, the cholesteric liquid crystal can prevent transmission of light having a specific wavelength by adjusting the axial direction of the spiral axis described above, the molecular arrangement of each layer, and the like. Therefore, the cholesteric liquid crystal layer171is formed by cholesteric liquid crystal adjusted to suppress transmission of light around 700 nm.

<Description of Cholesteric Liquid Crystal Layer>

The cholesteric liquid crystal layer171inFIG.11will be described with reference toFIG.12andFIG.14.

FIG.12is a diagram illustrating a camera module in a case where the adhesive22and the cholesteric liquid crystal layer171are not provided in the semiconductor chip160ofFIG.11. In this case, light incident on a camera module190inFIG.12is condensed via the lens group15and is incident on the cover glass14. Transmission of infrared light of the light incident on the cover glass14is suppressed by an IR cut filter added to the cover glass14.FIG.13is a diagram illustrating a relationship between a wavelength and transmittance of light incident on the cover glass14at this time.

InFIG.13, a horizontal axis represents a wavelength [nm] of light incident on the cover glass14, and a vertical axis represents transmittance [96] of the light in the cover glass14. Furthermore, a solid line inFIG.13represents a relationship between a wavelength and transmittance of light incident on the cover glass14and having an incident angle of zero degrees, and a dotted line represents a relationship between the wavelength and transmittance of light having an incident angle of 30 degrees.

As illustrated inFIG.13, the IR cut filter added to the cover glass14suppresses transmission of infrared light having a wavelength longer than the wavelength around 700 nm, but the relationship between the wavelength and transmittance of light depends on the incident angle. As a result, ghost, color unevenness, or the like occurs in an image captured by the solid-state imaging element21due to the light passing through the cover glass14and incident on a semiconductor chip191.

On the other hand, in the semiconductor chip160inFIG.11, since the cholesteric liquid crystal layer171is provided, the cholesteric liquid crystal layer171suppresses transmission of light having a wavelength around 700 nm of the light passing through the cover glass14and incident on the semiconductor chip160.FIG.14is a diagram illustrating a relationship between a wavelength and transmittance of light incident on the cholesteric liquid crystal layer171by indicating with a thick solid line.

InFIG.14, a horizontal axis represents a wavelength [nm] of light incident on the cover glass14or the cholesteric liquid crystal layer171, and a vertical axis represents transmittance [%] of the light in the cover glass14or the cholesteric liquid crystal layer171. As in the case ofFIG.13, a thin solid line inFIG.14represents a relationship between a wavelength and transmittance of light incident on the cover glass14and having an incident angle of zero degrees, and a dotted line represents a relationship between the wavelength and transmittance of light having an incident angle of 30 degrees.

As indicated by a thick solid line inFIG.14, in the cholesteric liquid crystal layer171, transmission of light having a wavelength around 700 nm of the incident light is suppressed without depending on the incident angle. Thus, it is possible to reduce the influence of variation in the relationship between a wavelength and transmittance of the incident light depending on the incident angle in the cover glass14as indicated by the thin solid line and dotted line inFIG.14. As a result, the occurrence of ghost, color unevenness, or the like is suppressed in an image formed by light passing through the cover glass14, and passing through this cholesteric liquid crystal layer171to be incident on the solid-state imaging element21, and the image quality is improved.

<Example of Manufacturing Method of First Configuration Example of Second Embodiment of Semiconductor Chip>

FIG.15is a diagram for illustrating an example of a manufacturing method for the semiconductor chip160ofFIG.11.

The entire steps ofFIG.15are performed in a unit of a wafer-like semiconductor substrate31on which one or more semiconductor chips160are formed, but inFIG.15, for convenience of description, only a region of one semiconductor chip160among one or more semiconductor chips160formed from the wafer-like semiconductor substrate31is illustrated.

Since step S61A and step S62A inFIG.15are similar to step S1A and step S2A inFIG.4, the description thereof will be omitted.

Furthermore, in step S61B, a temporary bonding resin (not illustrated) is applied to the lower side of a glass substrate211, and the cholesteric liquid crystal layer171is formed on the temporary bonding resin.

In step S63, the semiconductor substrate31and the cholesteric liquid crystal layer171formed in step S61B are adhered via the adhesive22applied to the semiconductor substrate31in step S62A. As a result, the cholesteric liquid crystal layer171is formed on the upper side (light incident side) of the solid-state imaging element21on which the wiring32is not yet formed.

Next, in step S64, the semiconductor substrate31is thinned, and the wiring32is formed on the lower side of the semiconductor substrate31. Finally, in step S65, the glass substrate211is peeled off and division into individual pieces is performed to form the semiconductor chip160.

<Second Configuration Example of Second Embodiment of Semiconductor Chip>

FIG.16is a diagram illustrating a second configuration example of the second embodiment of the semiconductor chip to which the present technology is applied.

InFIG.16, a portion corresponding to that inFIG.11is assigned with the same reference sign and the detailed description of the portion will be omitted.

As illustrated inFIG.16, a semiconductor chip250is different from the semiconductor chip160inFIG.11in that a flat layer251is formed instead of the adhesive22. Specifically, in the semiconductor chip250, the flat layer251is formed on the upper side (light incident side) of the solid-state imaging element21.

Note that although not illustrated, the configuration of the camera module including the semiconductor chip250is a configuration in which the semiconductor chip160of the camera module150inFIG.11is replaced with the semiconductor chip250.

<Example of Manufacturing Method of Second Configuration Example of Second Embodiment of Semiconductor Chip>

FIG.17andFIG.18are diagrams for explaining an example of a manufacturing method for the semiconductor chip250ofFIG.16.

The entire steps ofFIG.17andFIG.18are performed in a unit of a wafer-like semiconductor substrate31on which one or more semiconductor chips250are formed, but inFIG.17andFIG.18, for convenience of description, only a region of one semiconductor chip250among one or more semiconductor chips250formed from the wafer-like semiconductor substrate31is illustrated.

In step S71ofFIG.17, the solder resist33is formed on the lower side of the wafer-like semiconductor substrate31having the pixel region, and the solid-state imaging element21, of which the on-chip lens34is formed on the upper side and on which the wiring32is not formed yet, is formed. Next, in step S72, a temporary bonding resin271is applied onto the solid-state imaging element21on which the wiring32is not yet formed.

In step S73, a glass substrate272is attached, via the temporary bonding resin271, onto the solid-state imaging element21on which the wiring32is not yet formed. In step S74, the semiconductor substrate31is thinned, and the wiring32is formed on the lower side of the semiconductor substrate31. As a result, the solid-state imaging element21onto which the glass substrate272is adhered via the temporary bonding resin271is formed. In step S75, a laminate tape273is adhered to the side of the solid-state imaging element21to which the glass substrate272is not adhered, that is, the surface on the lower side (back surface side) of the wiring32.

In step S76inFIG.18, the temporary bonding resin271and the glass substrate272are peeled off. In step S77, the flat layer251is formed on the upper side of the solid-state imaging element21. In step S78, the cholesteric liquid crystal layer171is formed on the upper side (light incident side) of the flat layer251. Finally, in step S79, the laminate tape273is peeled off and division into individual pieces is performed to form the semiconductor chip250.

As described above, the second embodiment of the semiconductor chip to which the present technology is applied includes the solid-state imaging element21and the cholesteric liquid crystal layer171provided on the light incident side with respect to the solid-state imaging element21, and thus the image quality of the captured image can be improved.

Specifically, the cholesteric liquid crystal layer171suppresses transmission of light having a wavelength around 700 nm among light incident via the lens group15and the cover glass14. Thus, it is possible to reduce the influence of variation in the relationship between a wavelength and transmittance of the incident light depending on the incident angle in the IR cut filter added to the cover glass14. As a result, the occurrence of ghost, color unevenness, or the like is suppressed in an image formed by light passing through the cover glass14, and passing through this cholesteric liquid crystal layer171to be incident on the solid-state imaging element21, and the image quality is improved.

Note that in the second embodiment, only the cholesteric liquid crystal layer171that suppresses transmission of light having a wavelength around 700 nm is provided, but by further providing a cholesteric liquid crystal layer that suppresses transmission of light having a longer wavelength, a higher performance IR cut function can be realized.

Furthermore, in the second embodiment, it is also possible to provide a cholesteric liquid crystal layer that suppresses transmission of light in the entire wavelength band of infrared light instead of the wavelength band at the boundary between infrared light and visible light. In this case, the infrared light in the entire wavelength band may be blocked by the cholesteric liquid crystal layer without adding the IR cut filter to the cover glass14.

Moreover, although the glass substrate is not formed on the cholesteric liquid crystal layer171in the second embodiment, the glass substrate may be formed.

3. Third Embodiment of Semiconductor Chip

<First Configuration Example of Camera Module>

FIG.19is a diagram illustrating a configuration example of a camera module including a first configuration example of a third embodiment of the semiconductor chip to which the present technology is applied.

InFIG.19, a portion corresponding to that inFIG.1andFIG.11is assigned with the same reference sign and the detailed description of the portion will be omitted.

A camera module300inFIG.19is different from the camera module10inFIG.1in that a semiconductor chip310is provided instead of the semiconductor chip12. The semiconductor chip310is different from the semiconductor chip12inFIG.1in that both the cholesteric liquid crystal layer23and the cholesteric liquid crystal layer171are provided.

Specifically, in the semiconductor chip310, the cholesteric liquid crystal layer23is provided on the upper side (light incident side) with respect to the solid-state imaging element21. The cholesteric liquid crystal layer171is provided on the cholesteric liquid crystal layer23, and the glass substrate24is provided on the cholesteric liquid crystal layer171. That is, the cholesteric liquid crystal layer23and the cholesteric liquid crystal layer171are stacked between the glass substrate24and the solid-state imaging element21.

Light incident on the camera module300is condensed by the lens group15and is incident on the cover glass14. Transmission of infrared light among the light incident on the cover glass14is suppressed by an IR cut filter added to the cover glass14. The light transmitted through the IR cut filter is incident on the semiconductor chip310.

The light incident on the semiconductor chip310is incident on the cholesteric liquid crystal layer171via the glass substrate24, and transmission of light having a wavelength around 700 nm among the light is suppressed. The light transmitted through the cholesteric liquid crystal layer171is incident on the solid-state imaging element21via the cholesteric liquid crystal layer23and the adhesive22, and thus imaging is performed. Among the light incident on the solid-state imaging element21, the light in the critical angle range reflected by the sensor surface is reflected by the lower surface of the cholesteric liquid crystal layer23and is incident on the vicinity of the light source on the sensor surface again.

<Second Configuration Example of Camera Module>

FIG.20is a diagram illustrating a configuration example of a camera module including a second configuration example of a third embodiment of the semiconductor chip to which the present technology is applied.

InFIG.20, a portion corresponding to that inFIG.19is assigned with the same reference sign and the detailed description of the portion will be omitted.

A camera module350inFIG.20is different from the camera module300inFIG.19in that a semiconductor chip360is provided instead of the semiconductor chip310inFIG.19. The semiconductor chip360is different from the semiconductor chip310inFIG.19in that the cholesteric liquid crystal layer171is provided on the upper side (light incident side) of the glass substrate24. That is, in the semiconductor chip360, the glass substrate24is sandwiched between the cholesteric liquid crystal layer171and cholesteric liquid crystal layer23.

Light incident on the camera module350is condensed by the lens group15and is incident on the cover glass14. Transmission of infrared light of the light incident on the cover glass14is suppressed by the IR cut filter added to the cover glass14, and the light transmitted through the IR cut filter is incident on the semiconductor chip360.

The light incident on the semiconductor chip360is incident on the cholesteric liquid crystal layer171, and transmission of light having a wavelength around 700 nm among the light is suppressed. The light transmitted through the cholesteric liquid crystal layer171is incident on the solid-state imaging element21via the glass substrate24, the cholesteric liquid crystal layer23, and the adhesive22, and thus imaging is performed. Among the light incident on the solid-state imaging element21, the light in the critical angle range reflected by the sensor surface is reflected by the lower surface of the cholesteric liquid crystal layer23and is incident on the vicinity of the light source on the sensor surface again.

As described above, since the third embodiment of the semiconductor chip to which the present technology is applied is a combination of the first embodiment and the second embodiment, the same effects as those in the first embodiment and the second embodiment are obtained.

Note that the cholesteric liquid crystal layer23and the cholesteric liquid crystal layer171have different reflection characteristics. Specifically, the cholesteric liquid crystal layer23has a reflection characteristic depending on an incident angle that light in the critical angle range is reflected, but light at an angle outside the critical angle range is transmitted. However, the reflection characteristic of the cholesteric liquid crystal layer171does not depend on the incident angle. For example, in a case where light having a wavelength around 700 nm is incident at an angle outside the critical angle range (for example, vertically), the cholesteric liquid crystal layer23does not reflect the light since the light is incident at an angle outside the critical angle range. However, the cholesteric liquid crystal layer171has a difference in characteristic that the light is reflected since the light has a wavelength around 700 nm. The reflection described herein means that 90% or more of incident light is reflected.

Furthermore, in the first to third embodiments, the cholesteric liquid crystal layer is used to suppress transmission of light in the critical angle range or light having a wavelength around 700 nm, but any cholesteric liquid crystal layer may be used as long as the cholesteric liquid crystal layer has the same function. For example, instead of the cholesteric liquid crystal layer171, an organic film or the like having a color element that suppresses transmission of light having a wavelength around 700 nm may be used.

Furthermore, in the first to third embodiments, the solid-state imaging element21is a back-illumination image sensor, but may be a front-illumination image sensor. Furthermore, the solid-state imaging element21may be a stacked image sensor in which a pixel region and a circuit region are formed on different substrates and are stacked.

4. Application Example to Electronic Device

The semiconductor chip12(80,100,120,160,250,310,360) described above can be applied to various electronic devices such as an imaging device such as a digital still camera and a digital video camera, a mobile phone with an imaging function, or other devices having an imaging function.

FIG.21is a block diagram illustrating a configuration example of the imaging device as the electronic device to which the present technology is applied.

An imaging device1001illustrated inFIG.21includes an optical system1002, a shutter device1003, a solid-state imaging device1004, a driving circuit1005, a signal processing circuit1006, a monitor1007, and a memory1008, and can capture a still image and a moving image.

The optical system1002includes one or more lenses, guides light (incident light) from a subject to the solid-state imaging device1004, and forms an image on a light receiving surface of the solid-state imaging device1004.

The shutter device1003is disposed between the optical system1002and the solid-state imaging device1004, controls a light radiation period to the solid-state imaging device1004and a light-shielding period according to control of the driving circuit1005.

The solid-state imaging device1004includes the above-described semiconductor chip12(80,100,120,160,250,310,360). The solid-state imaging device1004accumulates signal charge during a certain period according to the light forming an image on the light receiving surface via the optical system1002and the shutter device1003. The signal charge stored in the solid-state imaging device1004is transferred according to a driving signal (timing signal) supplied from the driving circuit1005.

The driving circuit1005outputs the driving signal for controlling transfer operation of the solid-state imaging device1004and shutter operation of the shutter device1003to drive the solid-state imaging device1004and the shutter device1003.

The signal processing circuit1006performs various types of signal processing on the signal charge output from the solid-state imaging device1004. The image (image data) obtained by the signal processing performed by the signal processing circuit1006is supplied to the monitor1007to be displayed or supplied to the memory1008to be stored (recorded).

Also in the imaging device1001configured as described above, the image quality of the captured image can be improved by applying the semiconductor chip12(80,100,120,160,250,310,360) as the solid-state imaging device1004.

5. Usage Example of Semiconductor Chip

FIG.22is a diagram illustrating a usage example of using the above-described semiconductor chip12(80,100,120,160,250,310,360).

The above-described semiconductor chip12(80,100,120,160,250,310,360) can be used, for example, in various cases of sensing light such as visible light, infrared light, ultraviolet light, and X-ray as described below.A device which captures an image to be used for viewing such as a digital camera and portable equipment with a camera functionA device used for traffic control, such as an in-vehicle sensor that captures images of the forward side, rearward side, surrounding, inside of an automobile, a monitoring camera that monitors traveling vehicles and roads, and a distance measuring sensor that measures a distance between vehicles, for safe driving such as automatic stop, recognition of a driver's condition, and the like.A device used for home electric appliances such as a TV, a refrigerator, and an air conditioner in order to capture an image of a gesture of a user and perform a device operation according to the gesture.A device used for medical care or health care, such as an endoscope or a device used for performing angiography by receiving infrared light.A device used for security, such as a monitoring camera for crime prevention or a camera for person authentication.A device used for beauty care, such as a skin measuring device for imaging skin or a microscope for imaging scalp.A device used for sports, such as an action camera for sports or a wearable camera for sports.A device used for agriculture such as a camera for monitoring conditions of fields and crops.

6. Application Example to Endoscopic Surgery System

The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

FIG.24is a block diagram depicting an example of a functional configuration of the camera head11102and the CCU11201depicted inFIG.23.

An example of the endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the endoscope11100, (the imaging unit11402of) the camera head11102, (the image processing unit11412of) the CCU11201, and the like among the configurations described above. Specifically, for example, the semiconductor chip12(80,100,120,160,250,310,360) according to the above-described embodiment can be applied to the imaging unit10402. By applying the technology according to the present disclosure to the imaging unit10402, the image quality of the surgical image can be improved.

Note that here, the endoscopic surgery system has been described as an example, but the technology according to the present disclosure may be applied to, for example, a microscopic surgery system or the like.

7. Application Example to Mobile Body

The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be implemented as a device mounted on any type of mobile body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a ship, a robot, and the like.

The example of the vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the imaging section12031among the above-described configurations. Specifically, for example, the semiconductor chip12(80,100,120,160,250,310,360) according to the above-described embodiment can be applied to the imaging section12031. By applying the technology according to the present disclosure to the imaging section12031, the image quality of the captured image can be improved. Furthermore, it is possible to reduce driver's fatigue and increase the safety of the driver and vehicle by using the obtained high-quality captured image.

The embodiment of the present technology is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present technology.

For example, it is possible to adopt a combination of all or some of a plurality of embodiments described above.

The effects described in the present description are merely examples and are not limited, and there may be other effects.

Note that the present technology may also have following configurations.

A semiconductor chip including:an imaging element; anda liquid crystal layer provided on a side from which light is incident with respect to the imaging element.

The semiconductor chip according to (1),in which the liquid crystal layer is formed by cholesteric liquid crystal.

The semiconductor chip according to (1) or (2), further includinga glass provided on the side from which the light is incident with respect to the liquid crystal layer, in which the liquid crystal layer reflects light of which an incident angle on the glass is larger than a critical angle among the light reflected by the imaging element.

The semiconductor chip according to (3),in which the light reflected by the liquid crystal layer is light in a range in which the incident angle on the glass ranges from the critical angle to an angle larger than the critical angle by a predetermined angle.

The semiconductor chip according to (3) or (4), further includinga light absorption layer formed along an outer periphery of the semiconductor chip and provided on the side from which the light is incident with respect to the imaging element,in which the liquid crystal layer is formed on an inner side of the light absorption layer.

The semiconductor chip according to any one of (3) to (5), further includinganother liquid crystal layer that suppress transmission of light having a predetermined wavelength among the incident light and is provided on the side from which the light is incident with respect to the imaging element.

The semiconductor chip according to (6),in which the another liquid crystal layer is provided on the side from which the light is incident with respect to the liquid crystal layer.

The semiconductor chip according to (7),in which the glass is provided on the side from which the light is incident with respect to the another liquid crystal layer.

The semiconductor chip according to (7),in which the another liquid crystal layer is provided on the side from which the light is incident with respect to the glass.

The semiconductor chip according to (1) or (2),in which the liquid crystal layer suppresses transmission of light having a predetermined wavelength among the incident light.

The semiconductor chip according to (10), further includingan IR cut filter provided on the side from which the light is incident with respect to the liquid crystal layer,in which the liquid crystal layer suppresses the transmission of the light having the predetermined wavelength among the light incident through the IR cut filter.

The semiconductor chip according to (11),in which the liquid crystal layer suppresses transmission of light in a wavelength band at a boundary between infrared light and visible light among the incident light.

The semiconductor chip according to any one of (1) to (7) and (9) to (12), further includingan adhesive formed along an outer periphery of the semiconductor chip between the imaging element and the liquid crystal layer,in which a space is formed on an inner side of the adhesive between the imaging element and the liquid crystal layer.

A manufacturing method for a semiconductor chip, the method including:forming an imaging element; andforming a liquid crystal layer on a side from which light is incident with respect to the imaging element.

The manufacturing method for a semiconductor chip according to (14), further including:forming the liquid crystal layer on a glass; andadhering the imaging element to the liquid crystal layer.

The manufacturing method for a semiconductor chip according to (15), further includingpeeling off the glass.

The manufacturing method for a semiconductor chip according to (14), further including:applying an adhesive on the imaging element;forming the liquid crystal layer on the adhesive; andadhering a glass onto the liquid crystal layer.

The manufacturing method for a semiconductor chip according to (14), further including:forming a flat layer on the imaging element;forming a spacer along an outer periphery of the semiconductor chip on the flat layer;dropping liquid crystal for forming the liquid crystal layer on an inner side of the spacer on the flat layer; andadhering a glass to the spacer to form the liquid crystal layer between the glass and the flat layer.

The manufacturing method for a semiconductor chip according to (14), further including:applying a resin onto the imaging element;adhering a glass onto the imaging element via the resin,adhering a laminate tape to a surface of the imaging element on a side to which the glass is not adhered;peeling off the resin and the glass;forming a flat layer on the imaging element;forming the liquid crystal layer on the flat layer; andpeeling off the laminate tape.

An electronic device including:a semiconductor chip includingan imaging element, anda liquid crystal layer provided on a side from which light is incident with respect to the imaging element; anda signal processing circuit configured to process a signal from the semiconductor chip.

REFERENCE SIGNS LIST