Image sensors, imaging devices

Abstract

An image sensor according to the present invention is provided with: a semiconductor substrate in which a plurality of pixels having a photoelectric conversion element are arranged in two dimensions; and a magnetic detection unit for detecting magnetic change corresponding to change in the position relative to an imaging lens that guides light from a subject to the pixels.

Description

[Technical Field]

[0001] The present technology relates to an image sensor and an imaging device, and more particularly to a technology for detecting the relative position between an image sensor and an imaging lens using a magnetic sensor. [Background technology]

[0002] Camera modules, particularly those used in mobile devices such as smartphones, are becoming increasingly sophisticated, and are equipped with magnetic sensors such as Hall elements for detecting the position of the imaging lens within the camera module for optical image stabilization. For example, Patent Document 1 listed below discloses a camera module that includes four Hall elements for detecting the position of an imaging lens in a direction perpendicular to the optical axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-146022 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in conventional camera modules, such as the camera module of Patent Document 1, the magnetic sensor for detecting the lens position is mounted as an independent component, and providing the magnetic sensor results in an increase in the size of the camera module.

[0005] The present technology has been made in consideration of the above circumstances, and aims to suppress an increase in size of an imaging unit that captures images by including an imaging lens and an image sensor, which would otherwise be caused by providing a magnetic detection unit. [Means for solving the problem]

[0006] The image sensor according to the present technology includes a semiconductor substrate on which a plurality of pixels each having a photoelectric conversion element are arranged two-dimensionally, and a magnetic detection unit that detects magnetic changes in response to changes in the relative position with respect to an imaging lens that guides light from a subject to the pixels. According to the above configuration, the magnetic detection unit is provided in the image sensor.

[0007] In addition, the imaging device according to the present technology includes an image sensor having a semiconductor substrate on which a plurality of pixels, each having a photoelectric conversion element, are arranged two-dimensionally, and a magnetic detection unit that detects magnetic changes corresponding to changes in the relative position with respect to an imaging lens that guides light from a subject to the pixels, and an image signal processing unit that performs signal processing on an imaging image signal obtained by the image sensor. Such an imaging device also provides the same effects as the image sensor according to the present technology described above. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of the internal configuration of an imaging device including an image sensor according to a first embodiment of the present technology. [Figure 2] 1 is a schematic vertical cross-sectional view of an imaging unit included in an imaging device according to a first embodiment. [Figure 3] FIG. 2 is an exploded perspective view of a part of the imaging section including the movable unit. [Figure 4] 4 is a diagram schematically illustrating the positional relationship between each magnetic sensor formed in the image sensor and each magnet formed in the lens unit holder. FIG. [Figure 5] An explanatory diagram of the X-axis and Y-axis directions. [Figure 6] 5A and 5B are diagrams showing a schematic view of changes in the detection values ​​of the magnetic sensors in accordance with the displacement of the imaging lens. [Figure 7] FIG. 2 is a diagram illustrating an example of an electrical configuration related to optical shake correction in the imaging unit of the first embodiment. [Figure 8] FIG. 10 is an explanatory diagram of an example in which only two magnetic sensors are provided. [Figure 9]9 is a diagram similar to FIG. 6, showing how the detected values ​​of the magnetic sensors shown in FIG. 8 change with the displacement of the imaging lens. [Figure 10] FIG. 2 is an explanatory diagram of tilt of an imaging lens. [Figure 11] 5A and 5B are diagrams showing a schematic diagram of changes in the detected values ​​of the magnetic sensors in accordance with tilt of the imaging lens. [Figure 12] FIG. 10 is a diagram for explaining the configuration of an image sensor according to a second embodiment. [Figure 13] FIG. 10 is a diagram illustrating the relationship between focus adjustment of the imaging lens and the detection value of the axial magnetic sensor. [Figure 14] FIG. 10 is a diagram showing an example of the electrical configuration of an imaging unit compatible with five-axis detection. [Figure 15] 2 is an explanatory diagram of a semiconductor substrate and wiring layers included in the image sensor according to the embodiment; [Figure 16] FIG. 1 is an explanatory diagram of a TMR sensor according to an embodiment. [Figure 17] 3A and 3B are diagrams for explaining the structure of an MTJ portion in an embodiment. [Figure 18] 1A to 1C are diagrams illustrating an example of a process for forming a TMR sensor according to an embodiment. [Figure 19] 1A to 1C are explanatory diagrams illustrating an example of forming a GMR element according to an embodiment. [Figure 20] FIG. 2 is an explanatory diagram of perpendicular magnetic anisotropy and in-plane magnetic anisotropy. [Figure 21] FIG. 2 is an explanatory diagram of a magnetic field generated by a magnet. [Figure 22] 10 is a diagram showing an example of the change in the magnetization state of the MTJ portion with respect to the change in the distance between the MTJ portion and the magnet, and the change characteristics of the electrical resistance of the MTJ portion. [Figure 23] 10 is a diagram showing the change characteristics of the Z component of the magnetic field in the MTJ portion when the MTJ portion is displaced in the X-axis direction, and the change characteristics of the read voltage of the MTJ portion. [Figure 24] 10 is a diagram showing an example of the change in the magnetization state of the MTJ section with respect to the change in the distance between the MTJ section and the magnet when a modified MTJ section is used, and the change characteristics of the electrical resistance of the MTJ section. [Figure 25] 10 is a diagram showing the change characteristics of the X component of the magnetic field in the MTJ portion and the change characteristics of the read voltage of the MTJ portion when the MTJ portion is displaced in the X-axis direction as a modified example. FIG. [Figure 26] 10A and 10B are diagrams showing an example of the shape of a free magnetic layer in an MTJ portion. [Figure 27] 10A and 10B are explanatory diagrams illustrating an example in which a soft magnetic body is provided for each magnetic sensor. [Figure 28] 10A and 10B are explanatory diagrams of modified examples relating to the arrangement of magnetic sensors. [Figure 29] 10A and 10B are explanatory diagrams illustrating a modification of the manner in which an image sensor is connected to a wiring board. DETAILED DESCRIPTION OF THE INVENTION

[0009] The embodiments will be described below in the following order. <1. First embodiment> (1-1. Configuration of the imaging device) (1-2. Configuration of the imaging unit) 2. Second Embodiment <3. About magnetoresistive effect elements> <4. Modifications> <5. Summary of embodiments> <6. This technology>

[0010] <1. First embodiment> (1-1. Configuration of the imaging device) FIG. 1 is a diagram showing an example of the internal configuration of an imaging device 50 including an image sensor 1 according to a first embodiment of the present technology. In this example, the imaging device 50 is configured as a portable information processing device such as a smartphone or a tablet terminal.

[0011] As shown in the figure, the imaging device 50 includes an imaging section 51 that has an optical system 2 and an image sensor 1 for imaging and performs imaging, and an image signal processing section 52 that inputs the captured image signal obtained by the image sensor 1 and performs predetermined signal processing. The imaging device 50 also includes a CPU (Central Processing Unit) 53, a ROM (Read Only Memory) 54, a RAM (Random Access Memory) 55, an input / output interface 56, an input unit 57, a display unit 58, an audio output unit 59, a memory unit 60, a communication unit 61, and a bus 62.

[0012] The imaging unit 51 includes the image sensor 1 and optical system 2 described above, as well as a focusing coil 3, a shake correction coil 4, a control unit 5, and a motion sensor 6.

[0013] The image sensor 1 is configured by, for example, a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor, etc. The image sensor 1 is configured by having a semiconductor substrate (semiconductor substrate 1s described later) on which a plurality of pixels, each having a photoelectric conversion element such as a photodiode, are arranged two-dimensionally, and outputs an electrical signal obtained by photoelectric conversion for each pixel as a captured image signal. In this example, the image sensor 1 has a magnetic detection unit 1a. This magnetic detection unit 1a is configured to detect magnetic changes in response to changes in the relative position with respect to an imaging lens (imaging lens 10) that will be described later that the optical system 2 has, and details of this magnetic detection unit 1a will be described later.

[0014] The optical system 2 is configured to include optical components for imaging, such as an imaging lens 10 (described later) for guiding light from a subject to pixels of the image sensor 1.

[0015] The focusing coil 3 constitutes an actuator for realizing focus adjustment by displacing the coil in the optical axis direction. The vibration reduction coil 4 constitutes an actuator for realizing optical vibration reduction by displacing the imaging lens 10 in a direction perpendicular to the optical axis. An example of a mechanical configuration for displacing the imaging lens 10 for focus adjustment and optical blur correction will be described later.

[0016] The control unit 5 controls the driving of the focusing coil 3 and the vibration reduction coil 4 to achieve focus adjustment and optical vibration reduction. The focusing coil 3 is controlled by autofocus control based on a predetermined control method such as a contrast method or a phase difference method. Moreover, the control of the vibration reduction coil 4 is performed based on the detection value of the motion sensor 6 . The motion sensor 6 includes, for example, an acceleration sensor or a gyro sensor, and detects the motion of the imaging device 50. Based on the motion information detected by the motion sensor 6, the control unit 5 drives the shake correction coil 4 so that the shake (for example, hand shake) caused by the motion of the imaging device 50 is cancelled.

[0017] At this time, the control unit 5 controls the driving of the vibration reduction coil 4 based on the position information of the imaging lens 10 calculated based on the detection value of the magnetic detection unit 1a so as to prevent the imaging lens 10 from sticking to the end position of the movable range of the optical vibration reduction. Such anti-sticking control is a commonly used technique, and a detailed description thereof will be omitted here.

[0018] The image signal processing unit 52 performs pre-processing, synchronization processing, YC generation processing, resolution conversion processing, codec processing, etc. on the captured image signal input from the image sensor 1. Pre-processing involves clamping the R, G, and B black levels of the captured image signal from the image sensor 1 to a predetermined level, and correction between the R, G, and B color channels. Synchronization involves color separation, which ensures that the image data for each pixel contains all R, G, and B color components. For example, in the case of an image sensor using a Bayer array color filter, demosaic processing is performed as color separation processing. YC generation processing generates (separates) a luminance (Y) signal and a color (C) signal from the R, G, and B image data. Resolution conversion processing involves executing resolution conversion on image data that has undergone various signal processes. In codec processing, the image data that has undergone the various processes described above is encoded and a file is generated for recording or communication. In codec processing, moving image file formats such as MPEG-2 (Moving Picture Experts Group) and H.264 can be generated. Still image file formats such as JPEG (Joint Photographic Experts Group), TIFF (Tagged Image File Format), and GIF (Graphics Interchange Format) can also be generated.

[0019] The CPU 53 executes various processes in accordance with programs stored in the ROM 54 or programs loaded from a storage unit 60 (described later) into the RAM 55. The RAM 55 also stores data necessary for the CPU 53 to execute various processes, as appropriate. The CPU 53 , ROM 54 , and RAM 55 are connected to one another via a bus 62 .

[0020] The image signal processing unit 52 is connected to this bus 62. This enables the image signal processing unit 52 to communicate with the CPU 53 and store generated image files in the storage unit 60 via an input / output interface 56, which will be described later.

[0021] Also connected to the bus 62 is the input / output interface 56 . The input / output interface 56 can be connected to an input unit 57 for the user to perform input operations, a display unit 58 consisting of a liquid crystal panel or an organic EL (Electroluminescence) panel, an audio output unit 59 consisting of a speaker, a memory unit 60, a communication unit 61, etc.

[0022] The input unit 57 refers to an input device used by the user of the imaging device 50 . For example, various types of controls and operation devices such as a keyboard, a mouse, keys, a dial, a touch panel, a touch pad, a remote controller, etc. are assumed as the input unit 57. The input unit 57 detects a user operation, and the CPU 53 interprets a signal corresponding to the input operation.

[0023] The display unit 58 displays various types of information based on instructions from the CPU 53. For example, it displays images based on the image files stored in the storage unit 60 as described above, and various operation menus, icons, messages, etc., that is, displays as a GUI (Graphical User Interface).

[0024] The storage unit 60 is configured with a storage medium such as a hard disk drive (HDD), solid-state memory, etc. The storage unit 60 is used to store various content data such as the image files described above, as well as to store program data for the CPU 53 to execute various processes.

[0025] The communication unit 61 performs communication processing via a network including the Internet, and wired or wireless communication (for example, short-range wireless communication) with peripheral devices.

[0026] The input / output interface 56 is also connected to the control unit 5 in the imaging unit 51. This allows the CPU 53 to communicate with the control unit 5 via the input / output interface 56.

[0027] (1-2. Configuration of the imaging unit) The mechanical configuration of the imaging unit 51 will be described with reference to FIGS. FIG. 2 is a schematic vertical cross-sectional view of the imaging unit 51, and FIG. 3 is an exploded perspective view of a part of the imaging unit 51 including the movable unit 20 for displacing the imaging lens 10 for focus adjustment and optical shake correction.

[0028] 2, in the imaging unit 51, the image sensor 1 is physically connected to a wiring board 7 with an adhesive 8, and is also electrically and physically connected to the wiring board 7 by wire bonding with bonding wires W. The wiring board 7 is, for example, an interposer board, and functions as a circuit board for outputting an electrical signal from the image sensor 1 to the outside.

[0029] A spacer 9 is formed on the wiring board 7 so as to surround the image sensor 1. The spacer 9 is a spacer for ensuring a clearance between the image sensor 1 and the optical system 2.

[0030] A plurality of coils 4a that constitute the shake correction coil 4 are formed on the spacer 9, and a movable unit 20 is disposed above these coils 4a.

[0031] As shown in Figures 2 and 3, the movable unit 20 includes an imaging lens 10, a lens holder 11 that holds the imaging lens 10, a focusing coil 3 wound around the outer periphery of the imaging lens 10, a lens unit holder 12 that supports the lens holder 11 so that it can be displaced in the direction of the reference optical axis Ax and is supported from the wiring board 7 side so that it can be displaced in a direction perpendicular to the reference optical axis Ax, and a plurality of magnets 13 that are permanent magnets provided inside the lens unit holder 12.

[0032] Here, the reference optical axis Ax refers to the optical axis of the imaging optical system when the amount of optical shake correction caused by moving the imaging lens 10 (or the image sensor 1) is zero. In other words, this reference optical axis Ax is the optical axis when the imaging lens 10 is in its designed neutral position.

[0033] The lens unit holder 12 has an opening 12a in the center, and when the imaging lens 10 is in the neutral position, the lens unit consisting of the imaging lens 10, lens holder 11 and focusing coil 3 is housed in the opening 12a. The magnets 13 are arranged at the four corners of the lens unit holder 12.

[0034] In the movable unit 20, these four magnets 13 and the focusing coil 3 function as a focus actuator that displaces the imaging lens 10 in the direction of the reference optical axis Ax. Specifically, when the focusing coil 3 is energized, the magnetic field of the magnets 13 interacts with the magnetic field caused by the current flowing through the focusing coil 3, displacing the lens unit including the imaging lens 10 in the direction of the reference optical axis Ax.

[0035] The four magnets 13 also function as part of an actuator for optical shake correction. 3 shows the spacer 9 shown in FIG. 1 and the plurality of coils 4a formed on the spacer 9, together with the movable unit 20. In FIG. As shown in the figure, the coils 4a are respectively arranged at the four corners of the spacer 9, which is formed in a substantially rectangular frame shape. As a result, each coil 4a faces one of the four magnets 13 formed on the lens unit holder 12 side, which is arranged at the corresponding corner, in the direction of the reference optical axis Ax (see also FIG. 2).

[0036] With this configuration, the position of the lens unit holder 12 in the direction perpendicular to the reference optical axis Ax can be changed by controlling the currents flowing through the four coils 4a and thereby controlling the magnetic fields acting on the respective magnets 13. As described above, the lens unit including the imaging lens 10 is supported by the lens unit holder 12, and therefore, when the lens unit holder 12 is displaced in the direction perpendicular to the reference optical axis Ax as described above, the position of the imaging lens 10 also changes in conjunction with the direction perpendicular to the reference optical axis Ax. In other words, this makes it possible to perform optical shake correction by changing the position of the imaging lens 10 in the direction perpendicular to the reference optical axis Ax.

[0037] 3 shows the shield cover 15, which is not shown in Fig. 2. The shield cover 15 functions as a protective cover that covers the movable unit 20 and the spacer 9 (and the image sensor 1 located inside thereof) on the wiring board 7.

[0038] 2, although not shown in Fig. 3, an IR (infrared) cut filter 14 is disposed between the movable unit 20 and the image sensor 1. This cuts out infrared light from the light incident on the image sensor 1 from the imaging lens 10.

[0039] 2, the IC (Integrated Circuit) chip of the control unit 5 and the motion sensor 6 described in FIG. 1 are mounted on the wiring board 7, and also a memory unit 21 is mounted on the wiring board 7. The memory unit 21 is a storage device that stores correction values ​​for correcting variations in induced electromotive force detected depending on the lens position. The wiring board 7 is also provided with a connector section 22 on which various input / output terminals are formed.

[0040] The image sensor 1 of this embodiment is provided with a magnetic detection unit 1a that detects magnetic changes according to changes in the relative position with respect to the imaging lens 10 (FIGS. 2 and 3). In this example, the magnetic detection unit 1a has a plurality of magnetic sensors D1 that detect magnetic changes according to changes in the relative position with respect to the imaging lens 10 in a direction perpendicular to the reference optical axis Ax. Specifically, the magnetic detection unit 1a has four magnetic sensors D1 arranged at the four corners of the image sensor 1, as shown in FIG.

[0041] Each magnetic sensor D1 is configured with a magnetoresistive element. The magnetoresistive effect refers to a phenomenon in which electrical resistance changes when a magnetic field is applied. As will be described later, in this example, a TMR sensor (TMR sensor 30 described later) that detects magnetism using the TMR (Tunnel Magneto Resistance) effect is used as the magnetic sensor D1. The TMR effect is a type of magnetoresistance effect, a phenomenon in which electrical resistance changes depending on the direction of magnetization of two layers of ferromagnetic material sandwiching an insulator in an MTJ (Magnetic Tunnel Junction) element. Generally, when the magnetizations of the two ferromagnetic material layers are oriented in the same direction (parallel state), the resistance is low, and when they are oriented in opposite directions (antiparallel state), the resistance is high.

[0042] The TMR sensor can be formed using a semiconductor manufacturing process, and therefore can be formed very compactly inside the image sensor 1. As will be described later, in this example, each magnetic sensor D1 is formed inside the image sensor 1, for example, in a wiring layer (wiring layer 1m to be described later) stacked on the semiconductor substrate 1s.

[0043] 2 and 3, the outer size of the lens unit holder 12 on which the four magnets 13 are formed, specifically the outer size in a plane perpendicular to the reference optical axis Ax, is larger than the outer size of the image sensor 1. For this reason, the magnetic sensors D1 formed at the four corners of the image sensor 1 are positioned more inward than the magnets 13 formed at the four corners of the lens unit holder 12.

[0044] FIG. 4 is a diagram showing a schematic representation of the positional relationship between each magnetic sensor D1 formed in the image sensor 1 and each magnet 13 formed in the lens unit holder 12. As shown in FIG. Here, the left-right direction of the paper surface is the row direction of the image sensor 1, and the vertical direction is the column direction of the image sensor 1. As shown in the figure, the magnetic sensors D1 arranged at the four corners of the image sensor 1 are distinguished and referred to as magnetic sensors D1a, D1b, D1c, and D1d, respectively. Magnetic sensors D1a and D1b are located at one end in the row direction of the image sensor 1, and magnetic sensors D1c and D1d are located at the other end in the row direction of the image sensor 1. Furthermore, magnetic sensors D1a and D1d are located at one end in the column direction of the image sensor 1, and magnetic sensors D1b and D1c are located at the other end in the column direction of the image sensor 1.

[0045] The magnets 13 are also distinguished from one another and are referred to as magnets 13a, 13b, 13c, and 13d. As shown in the figure, the magnet 13 located closest to magnetic sensor D1a is referred to as magnet 13a, and the magnet 13 located closest to magnetic sensor D1b is referred to as magnet 13b. Similarly, the magnet 13 located closest to magnetic sensor D1c is referred to as magnet 13c, and the magnet 13 located closest to magnetic sensor D1d is referred to as magnet 13d. To be clear, "close" here means that the position is close in a direction perpendicular to the reference optical axis Ax.

[0046] 5 and 6, it will be explained that the magnetic sensors D1a, D1b, D1c, and D1d arranged as described above can detect the position of the imaging lens 10 in a direction perpendicular to the reference optical axis Ax. As an example, consider displacement of the imaging lens 10 in the X-axis direction and the Y-axis direction as shown in Fig. 5. The X-axis direction is a direction perpendicular to the reference optical axis Ax that is shifted by 45 degrees from the row direction of the image sensor 1, and the Y-axis direction is a direction perpendicular to the reference optical axis Ax that is perpendicular to the X-axis direction. The polarities of "+" and "-" in the X-axis direction and the Y-axis direction respectively define the direction of displacement of the imaging lens 10 from the neutral position in each axis.

[0047] Fig. 6 schematically shows how the detection values ​​of the magnetic sensors D1 change with displacement of the imaging lens 10. Specifically, Fig. 6 schematically shows, for each of the magnetic sensors D1a, D1b, D1c, and D1d, how the detection values ​​change with displacement of the imaging lens 10 in the X-axis direction (upper part of the figure) and how the detection values ​​change with displacement of the imaging lens 10 in the Y-axis direction (lower part of the figure). Here, each magnetic sensor D1 is configured so that the closer the distance to the magnet 13, the higher the detection value. When the imaging lens 10 is displaced from the negative side to the positive side in the X-axis direction, the magnet 13a approaches the magnetic sensor D1a, while the magnet 13c moves away from the magnetic sensor D1c. Therefore, when the imaging lens 10 is displaced from the negative side to the positive side in the X-axis direction, the detection value of the magnetic sensor D1a gradually increases, and the detection value of the magnetic sensor D1c gradually decreases. Furthermore, the distances between the magnetic sensors D1b and D1d and the magnets 13b and 13d, respectively, do not change substantially with displacement of the imaging lens 10 in the X-axis direction. Therefore, the detection values ​​of the magnetic sensors D1b and D1d do not change substantially with displacement of the imaging lens 10 in the X-axis direction.

[0048] On the other hand, when the imaging lens 10 is displaced from the negative side to the positive side in the Y-axis direction, the distances between the magnetic sensors D1a and D1c and the magnets 13a and 13c, respectively, remain almost unchanged, and as for the magnetic sensors D1b and D1d, the magnet 13d approaches the magnetic sensor D1d, while the magnet 13b moves away from the magnetic sensor D1b. Therefore, when the imaging lens 10 is displaced from the negative side to the positive side in the Y-axis direction, the detection values ​​of the magnetic sensors D1a and D1c remain almost unchanged, and as for the magnetic sensors D1b and D1d, the detection value of the magnetic sensor D1d gradually increases, while the detection value of the magnetic sensor D1b gradually decreases.

[0049] In this way, the magnetic sensors D1a, D1b, D1c, and D1d produce differences in the changes in their detection values ​​in response to displacement of the imaging lens 10 in the X-axis direction and the Y-axis direction, and based on the differences in the changes in the detection values ​​of each magnetic sensor D1, it is possible to detect the position of the imaging lens 10 in the XY plane, i.e., the position in any direction perpendicular to the reference optical axis Ax.

[0050] FIG. 7 is a diagram illustrating an example of an electrical configuration related to optical shake correction in the imaging unit 51. As shown in the figure, the image sensor 1 is provided with a magnetic detection unit 1a having magnetic sensors D1a, D1b, D1c, and D1d, as well as amplifiers 25a, 25b, 25c, and 25d that amplify and convert the detection signals from these magnetic sensors D1a, D1b, D1c, and D1d into digital values, and an output unit 1b that includes ADCs (Analog to Digital Converters) 26a, 26b, 26c, and 26d and outputs four systems of magnetic detection values ​​for each of the magnetic sensors D1a, D1b, D1c, and D1d.

[0051] The control unit 5 receives the magnetic detection values ​​from these four systems and performs a predetermined calculation based on the difference in the changes in the detection values ​​of the magnetic sensors D1a, D1b, D1c, and D1d in response to the displacement of the imaging lens 10 as described above, thereby detecting the position of the imaging lens 10. As described above, control unit 5 realizes optical shake correction by driving shake correction coil 4 based on the detection signal from motion sensor 6, and also performs control to prevent imaging lens 10 from sticking to an end position within the movable range of optical shake correction, based on information about the detected position of imaging lens 10.

[0052] Here, in order to realize position detection of the imaging lens 10 in a direction perpendicular to the reference optical axis Ax, at least two magnetic sensors D1 are required. FIG. 8 illustrates an example in which only magnetic sensors D1a and D1b are provided in the image sensor 1 as the magnetic sensor D1. 9 also shows how the detected values ​​of the magnetic sensors D1a and D1b change with the displacement of the imaging lens 10, similar to FIG.

[0053] As can be seen by referring to Figures 8 and 9, even if only magnetic sensors D1a and D1b are used, the change characteristics of the detection values ​​when the imaging lens 10 is displaced in the X-axis direction and when the imaging lens 10 is displaced in the Y-axis direction will be different for each magnetic sensor D1, and therefore it will be possible to detect the position of the imaging lens 10 in any direction perpendicular to the reference optical axis Ax based on the detection values ​​of these magnetic sensors D1.

[0054] Although only the magnetic sensors D1a and D1b are provided in this example, the position of the imaging lens 10 in the direction perpendicular to the reference optical axis Ax can be detected in the same way even when only the magnetic sensors D1c and D1d are provided.

[0055] Here, the relationship between the magnetic sensors D1a and D1b and the relationship between the magnetic sensors D1c and D1d correspond to the relationship between the "first direction magnetic sensor" and the "second direction magnetic sensor" in the present technology, respectively. Specifically, the first direction magnetic sensor is a magnetic sensor in which the change in the detection value in response to the displacement of the imaging lens 10 in a first direction (e.g., the X-axis direction), which is a predetermined direction among directions perpendicular to the reference optical axis Ax, is greater than the change in the detection value in response to the displacement of the imaging lens 10 in a second direction (e.g., the Y-axis direction), which is a direction perpendicular to the reference optical axis Ax and perpendicular to the first direction. On the other hand, the second direction magnetic sensor is a magnetic sensor in which the change in detection value in response to the displacement of the imaging lens 10 in the second direction is greater than the change in detection value in response to the displacement of the imaging lens 10 in the first direction.

[0056] By providing at least two magnetic sensors D1, one corresponding to the first direction magnetic sensor and the other corresponding to the second direction magnetic sensor as described above, it becomes possible to detect the position in any direction perpendicular to the reference optical axis Ax of the imaging lens 10.

[0057] In this embodiment, by arranging magnetic sensors D1 at the four corners of image sensor 1, it is also possible to detect the tilt angle of imaging lens 10 in response to control of tilting imaging lens 10 as optical shake correction.

[0058] FIG. 10 is an explanatory diagram of the tilt of the imaging lens 10. In FIG. As tilt, tilt in two directions, α direction and β direction shown in the figure, is considered. The tilt in the α direction is, for example, a tilt in which the axis of the imaging lens 10 is tilted in a plane parallel to the row direction of the image sensor 1, and the tilt in the β direction is, for example, a tilt in which the axis of the imaging lens 10 is tilted in a plane parallel to the column direction of the image sensor 1. The polarities of "+" and "-" in the α direction and β direction shown in the figure define the polarity of the tilt angle with the imaging lens 10 in the neutral position as the reference.

[0059] Figure 11 schematically shows how the detection values ​​of each magnetic sensor D1 change with tilt of the imaging lens 10. Specifically, for each of magnetic sensors D1a, D1b, D1c, and D1d, it shows how the detection values ​​change with tilt of the imaging lens 10 in the α direction (upper row in the figure) and how the detection values ​​change with tilt of the imaging lens 10 in the β direction (lower row in the figure). When the imaging lens 10 tilts from the negative side to the positive side in the α direction, the magnets 13c and 13d move closer to the magnetic sensors D1c and D1d, respectively, while the magnets 13a and 13b move farther away from the magnetic sensors D1a and D1b, respectively. Therefore, when the imaging lens 10 is displaced from the negative side to the positive side in the α direction, the detection values ​​of the magnetic sensors D1c and D1d gradually increase, and the detection values ​​of the magnetic sensors D1a and D1b gradually decrease.

[0060] On the other hand, when the imaging lens 10 tilts from the negative side to the positive side in the β direction, the magnets 13b and 13c move closer to the magnetic sensors D1b and D1c, respectively, while the magnets 13a and 13d move farther away from the magnetic sensors D1a and D1d, respectively. Therefore, with respect to the tilt from the negative side to the positive side in the β direction, the detection values ​​of the magnetic sensors D1b and D1c gradually increase, and the detection values ​​of the magnetic sensors D1a and D1d gradually decrease.

[0061] By providing the magnetic sensors D1 at the four corners of the image sensor 1 in this way, differences occur in the change patterns of the detected values ​​of the magnetic sensors D1 with respect to tilt in the α direction and tilt in the β direction of the imaging lens 10. Therefore, based on the difference in these change patterns, it is possible to detect the tilt angle of the imaging lens 10 in any direction.

[0062] Here, in order to enable tilt detection of the imaging lens 10, the magnetic detection unit 1a needs to satisfy the following structural conditions. In other words, the magnetic detection unit 1a is configured to have two magnetic sensors D1 (in the above example, a pair of magnetic sensors D1a and D1d, or a pair of magnetic sensors D1b and D1c) positioned opposite each other at both ends of the row direction of the image sensor 1, and two orthogonal magnetic sensors (in the above example, a pair of magnetic sensors D1a and D1b, or a pair of magnetic sensors D1c and D1d) positioned opposite each other at both ends of the column direction of the image sensor 1.

[0063] As described above, the two magnetic sensors D1 positioned opposite both ends in the row direction make it possible to detect the tilt angle in the α direction when the imaging lens 10 is tilted in the α direction, and the two magnetic sensors D1 positioned opposite both ends in the column direction make it possible to detect the tilt angle in the β direction when the imaging lens 10 is tilted in the β direction.

[0064] According to the above conditions, it is clear that the number of magnetic sensors D1 required to enable tilt detection need only be three or more, not four or more. Specifically, tilt detection is also possible by providing, for example, only magnetic sensors D1a, D1b, and D1d. In this case, the "two magnetic sensors D1 positioned opposite each other at both ends in the row direction" corresponds to the set of magnetic sensors D1a and D1d, and the "two magnetic sensors D1 positioned opposite each other at both ends in the column direction" corresponds to the set of magnetic sensors D1a and D1b.

[0065] 2. Second Embodiment Next, a second embodiment will be described. The second embodiment makes it possible to detect the position of the imaging lens 10 in the direction of the reference optical axis Ax. In the following description, parts that are the same as parts that have already been described will be given the same reference numerals and description thereof will be omitted.

[0066] Fig. 12 is a diagram for explaining the configuration of an image sensor 1A according to the second embodiment. Fig. 12 also shows the lens unit (imaging lens 10, lens holder 11, and focusing coil 3) and magnets 13 (13a, 13b, 13c, and 13d) formed on the lens unit holder 12, which are components of a movable unit 20 according to the second embodiment, along with the image sensor 1A.

[0067] The image sensor 1A differs from the image sensor 1 of the first embodiment in that it has a magnetic sensor as a coil-type sensor D2 formed of a coil on the incident surface side of the light from the subject. Although detailed illustration is omitted, this coil-type sensor D2 is formed of a coil formed on the surface of a semiconductor substrate 1s (described later) on the side on which light from the subject is incident. Specifically, in this example, the coil in the coil-type sensor D2 is disposed in the outer peripheral region of the effective pixel region. More specifically, the coil is formed in a region that is outer than the effective pixel region and inner than the formation region of the pads formed for wire bonding using the bonding wire W.

[0068] The coil-type sensor D2 as described above makes it possible to detect an induced electromotive force based on a magnetic field generated by the focusing coil 3, which is provided so as to be displaceable along the reference optical axis Ax together with the imaging lens 10. This induced electromotive force tends to become larger as the imaging lens approaches the image sensor, so the position of the imaging lens in the direction of the reference optical axis can be detected based on the detection value by the axial magnetic sensor. In FIG. 12, the magnetic field generated by the focusing coil 3 is schematically represented by dotted arrows.

[0069] FIG. 13 is a diagram illustrating the relationship between the focus adjustment of the imaging lens 10 and the detection value of the coil-type sensor D2. The horizontal axis in the diagram indicates the movable range of the imaging lens 10 due to focus adjustment (the movable range in the direction of the reference optical axis Ax), where "Infinit" in the diagram means infinity and "Macro" means the minimum distance to a subject that can be focused. When the imaging lens 10 is moved toward the "Infinit" side, the imaging lens 10 moves closer to the image sensor 1A, and conversely, when the imaging lens 10 is moved toward the "Macro" side, the imaging lens 10 moves farther away from the image sensor 1A.

[0070] As shown in the figure, the detection value of the coil-type sensor D2 exhibits a characteristic of decreasing as the imaging lens 10 moves from the "Infinite" side to the "Macro" side in the direction of the reference optical axis Ax (i.e., the detection value decreases as the imaging lens 10 moves away from the image sensor 1A).

[0071] It can be seen from FIG. 13 that the position of the imaging lens 10 in the direction of the reference optical axis Ax can be detected from the detection value of the coil-type sensor D2.

[0072] One possible method for detecting the position of the imaging lens 10 in the optical axis direction is to provide a magnet that is linked to the displacement of the imaging lens 10 in the optical axis direction. However, the configuration of the second embodiment makes the placement of such a magnet unnecessary, thereby enabling the imaging optical system to be made smaller and lighter.

[0073] Here, according to the image sensor 1A of the second embodiment provided with the magnetic sensor D1 and the coil-type sensor D2, it is possible to detect the position and orientation of the imaging lens 10 in a total of five axes, namely, directions (two axes) perpendicular to the reference optical axis Ax, tilt directions (two axes), and the direction of the reference optical axis Ax (one axis).

[0074] FIG. 14 is a diagram showing an example of the electrical configuration of the imaging unit 51 that supports such five-axis detection. As shown in the figure, the image sensor 1A includes a magnetic detection unit 1aA having a coil-type sensor D2 along with magnetic sensors D1a, D1b, D1c, and D1d, and an output unit 1bA having an amplifier 25f and an ADC 26f along with the aforementioned amplifiers 25a, 25b, 25c, and 25d, and ADCs 26a, 26b, 26c, and 26d. In the output section 1bA, an amplifier 25f amplifies the detection signal from the coil-type sensor D2, and an ADC 26f converts the detection signal amplified by the amplifier 25f into a digital value.

[0075] Similar to the previously described controller 5, controller 5A controls the driving of shake correction coil 4 for optical shake correction based on the detection signal of motion sensor 6, and controls the driving of focusing coil 3 for focus adjustment. Here, optical shake correction involves driving imaging lens 10 in the tilt direction. In response to this, control unit 5A detects the position of imaging lens 10 in a direction perpendicular to reference optical axis Ax and the tilt angle based on the outputs from ADCs 26a, 26b, 26c, and 26d, and also detects the position of imaging lens 10 in the direction of reference optical axis Ax based on the output from ADC 26f. By detecting the tilt angle of the imaging lens 10, it is possible to perform control in the tilt direction to prevent the imaging lens 10 from sticking to an end position of the movable range. Furthermore, it is conceivable that the detection information of the position of the imaging lens 10 in the direction of the reference optical axis Ax is used to drive the focusing coil 3. For example, it is conceivable that the information is used for feedback control to match the position of the imaging lens 10 in the direction of the reference optical axis Ax with a target position.

[0076] <3. About magnetoresistive effect elements> As described above, in this example, a TMR sensor is used as the magnetic sensor D1, which allows the magnetic sensor D1 to be formed in the wiring layer of the image sensor 1 (or 1A) using a semiconductor manufacturing process.

[0077] Fig. 15 is an explanatory diagram of the semiconductor substrate 1s and wiring layer 1m of the image sensor 1. Fig. 15A shows a schematic vertical cross-sectional structure of the image sensor 1, and Fig. 15B is a schematic exploded perspective view of the semiconductor substrate 1s and wiring layer 1m. The wiring layer 1m is laminated on the surface of the semiconductor substrate 1s opposite to the surface on which light from the subject is incident, and is configured by alternately laminating wiring formation layers on which wiring patterns are formed and insulating layers. As shown in the figure, each magnetic sensor D1 is formed in the wiring layer 1m.

[0078] 16A, the magnetic sensor D1 is configured with a plurality of TMR sensors 30. Specifically, the magnetic sensor D1 has a plurality of series-connected circuits in which a plurality of TMR sensors 30 are connected in series, and these series-connected circuits are connected in parallel. By configuring the magnetic sensor D1 with a plurality of TMR sensors 30 (MTJ elements) in this way, the noise resistance of the magnetic sensor D1 can be improved. 16A shows an example in which a plurality of TMR sensors 30 are arranged in a two-dimensional array, but a plurality of TMR sensors 30 can also be arranged in a one-dimensional array. In other words, it is also possible to have a configuration having only one of the above-mentioned series-connected circuits.

[0079] FIG. 16B is an explanatory diagram of a schematic vertical cross-sectional structure of the TMR sensor 30. Here, the case where the wiring layer 1m has three wiring formation layers, ie, a first wiring formation layer L1 to a third wiring formation layer L3, is illustrated. As shown in the figure, the TMR sensor 30 is configured to have a first contact 36 formed by a via that penetrates between the first wiring formation layer L1 and the second wiring formation layer L2, an MTJ portion 31 formed in the second wiring formation layer L2 and electrically connected to the first contact 36, and a second contact 37 formed by a via that penetrates between the second wiring formation layer L2 and the third wiring formation layer L3. In the first wiring formation layer L1, the wiring 35 electrically connected to the first contact 36 of one TMR sensor 30 is electrically connected to the first contact 36 of another TMR sensor 30. In the third wiring formation layer L3, the wiring 38 electrically connected to the second contact 37 of one TMR sensor 30 is electrically connected to the second contact 37 of another TMR sensor 30.

[0080] In the TMR sensor 30, the first contact 36, the MTJ portion 31, and the second contact 37 are arranged in the vertical direction as shown in FIG. 16B in order to pass a current in the vertical direction through the MTJ portion 31.

[0081] FIG. 17 is a diagram for explaining the structure of the MTJ section 31. As shown in FIG. As shown in the figure, the MTJ section 31 has a structure in which an underlayer, a pinned magnetic layer, an intermediate layer, a free magnetic layer, and a cap layer are stacked in this order. The underlayer is selected so as to optimize the crystallinity of the layers above the pinned magnetic layer, and may be made of Ta, Ru, Pt, Ni, Cr, or a laminated film of these materials. The pinned magnetic layer is a layer whose magnetization direction is substantially fixed relative to an external magnetic field, and may be made of Co, Fe, CoFeB, CoFe, a Co / Pt laminated film, a Co / Ni laminated film, or the like.

[0082] The pinned magnetic layer can also have a three-layer structure with a non-magnetic layer in between, as shown in the middle of the figure. In this three-layer pinned magnetic layer, the magnetizations of the first and second magnetic layers are coupled antiparallel, making it easier to pin the magnetization and also enabling control of the total leakage field from the pinned magnetic layer. Ir, Ru, etc. are used for the non-magnetic layer.

[0083] Furthermore, as shown in the lower part of the figure, the pinned magnetic layer can be further strengthened by placing an antiferromagnetic layer adjacent to it, which is made of PtMn, IrMn, FeMn, or the like.

[0084] The intermediate layer is important for magnetically separating the free magnetic layer and the pinned magnetic layer and for realizing the magnetoresistive effect. When the difference in the magnetization direction between the free magnetic layer and the pinned magnetic layer is Δθ, the electrical resistance of the MTJ section 31 is proportional to cos(Δθ). The intermediate layer can be an insulating barrier layer made of MgO, Al2O3, or the like.

[0085] The free magnetic layer is a layer whose magnetization direction changes in response to an external magnetic field, and may be made of Co, Fe, NiFe, NiCoFe, CoFeB, CoFe, Co / Pt laminated film, Co / Ni laminated film, etc. The free magnetic layer may also be made of a laminate of a magnetic material and a non-magnetic material, such as CoFeB / Mo / CoFeB. The cap layer is provided to prevent diffusion from the upper via and electrode and also to control the crystallinity of the free magnetic layer. Materials used for the cap layer include MgO, Ru, Pt, and W.

[0086] FIG. 18 shows an example of a process for forming a TMR sensor 30 having an MTJ portion 31. First, a first contact 36 made of, for example, W is formed on the wiring 35 in the first wiring formation layer L1, and is planarized by CMP (Chemical Mechanical Planarization) (FIG. 18A).

[0087] Next, in the second wiring-forming layer L2, the above-mentioned underlayer, pinned magnetic layer, intermediate layer, free magnetic layer, and cap layer are sequentially deposited by sputtering to form the MTJ film 31' (FIG. 18B). For example, Ta / Ru / CoFeB / Ru / CoFeB / MgO / CoFeB / Ru is used as the MTJ film 31'.

[0088] Next, a hard mask 39 made of, for example, Ta / SiO 2 is formed by plasma CVD (Chemical Vapor Deposition) and processed into a desired shape by plasma etching (FIG. 18C). The MTJ film 31' is processed into a desired shape by ion milling, and the MTJ portion 31 is formed (FIG. 18D).

[0089] Furthermore, a protective film 40 made of, for example, SiN is formed by plasma CVD (FIG. 18E). Finally, a second contact 37 made of, for example, Cu is formed by a hole drilling process and is electrically connected to the wiring 38 of the third wiring formation layer L3 (FIG. 18F).

[0090] Here, a metal layer can be used as the intermediate layer shown in FIG. 17 instead of the insulating barrier layer. In this case, the magnetoresistive effect is based on the GMR (Giant Magnetic Resistance) effect, not the TMR effect. Therefore, when the intermediate layer is a metal layer, it is generally called a GMR element (hereinafter referred to as GMR element 32). In this case, the metal layer used for the intermediate layer can be a layer made of Cu, Au, or the like.

[0091] In the case of the GMR element 32, since the intermediate layer is made of metal, the resistance is too small when a current is passed in a direction perpendicular to the film. Therefore, it is desirable to adopt a structure in which a current is passed in a direction parallel to the film surface.

[0092] FIG. 19 is an explanatory diagram of an example of forming the GMR element 32. As shown in the figure, the GMR element 32 is formed in the second wiring-forming layer L2 so as to connect two first contacts 36 formed between the first wiring-forming layer L1 and the second wiring-forming layer L2. This allows the current flowing from the wiring 35 through the first contacts 36 to flow in a direction parallel to the film surface in the GMR element 32.

[0093] Here, the magnetization directions of the free magnetic layer and the pinned magnetic layer are determined by the direction of the magnetic anisotropy of each magnetic layer and the external magnetic field. Magnetic anisotropy can be classified into perpendicular magnetic anisotropy (see Figure 20A), in which the magnetization tends to be oriented perpendicular to the film, and in-plane magnetic anisotropy (see Figure 20B), in which the magnetization tends to be oriented in the film plane. In this technology, magnetic layers with either magnetic anisotropy can be used.

[0094] Below, we will explain how a TMR sensor 30 having an MTJ section 31 can detect the position of the imaging lens 10 in a direction perpendicular to the reference optical axis Ax, taking as an example a case where the free magnetic layer has a relatively weak in-plane magnetic anisotropy (i.e., a property that makes it easy to orient magnetization in the vertical direction to some extent) and the fixed magnetic layer has vertical magnetic anisotropy.

[0095] FIG. 21 is an explanatory diagram of the magnetic field generated by the magnet 13. Figure 21 shows the positional relationship between the magnet 13 and the MTJ section 31, and also schematically shows the magnetization direction in the magnet 13, an image of the magnetic field generated by the magnet 13, and the magnetic field vector for the magnetic field acting on the MTJ section 31. Here, the X-axis direction and the Y-axis direction in the figure are the same as the X-axis direction and the Y-axis direction explained with reference to Fig. 5 etc. The Z-axis direction is the direction of the reference optical axis Ax.

[0096] 21, it can be seen that the magnetic field acting on the MTJ section 31 from the magnet 13 is dominated by the magnetic field component in the Z-axis direction (hereinafter also referred to as the Z component of the magnetic field).

[0097] FIG. 22 shows an example of the change in the magnetization state of the MTJ section 31 with respect to the change in the distance between the MTJ section 31 and the magnet 13, and the change characteristics of the electrical resistance of the MTJ section 31. When the distance between the MTJ unit 31 and the magnet 13 is long, the Z component (negative direction) of the magnetic field acting on the MTJ unit 31 from the magnet 13 is small, so the direction of magnetization in the free magnetic layer is tilted toward the opposite direction to the magnetization of the pinned magnetic layer rather than parallel to the plane. As the distance between the MTJ unit 31 and the magnet 13 becomes shorter and the Z component of the magnetic field increases, the direction of magnetization in the free magnetic layer passes through a state parallel to the plane and then tilts in the same direction as the magnetization of the pinned magnetic layer. As a result, as the distance between the MTJ section 31 and the magnet 13 becomes shorter, that is, as the Z-direction component of the magnetic field acting on the MTJ section 31 becomes larger, current flows more easily in the MTJ section 31, in other words, the electrical resistance becomes smaller. Therefore, the magnitude of the electrical resistance of the MTJ section 31 changes depending on the change in the distance from the magnet 13, and such a change in the electrical resistance of the MTJ section 31 can be detected as a change in voltage or a change in current, thereby detecting the position of the imaging lens 10 in a direction perpendicular to the reference optical axis Ax. The direction of change in the electrical resistance of the MTJ unit 31 relative to the distance from the magnet 13 can be reversed by reversing the direction of magnetization of the pinned magnetic layer.

[0098] For reference, FIG. 23 shows the change characteristics of the Z component of the magnetic field in the MTJ unit 31 and the change characteristics of the read voltage of the MTJ unit 31 when the MTJ unit 31 is displaced in the X-axis direction.

[0099] In the above example, the MTJ unit 31 detects changes in the Z component of the magnetic field. However, as a modified example, the MTJ unit 31 can also be configured to detect changes in the X component of the magnetic field (magnetic field component in the X-axis direction). In this case, the MTJ section 31 is configured so that the free magnetic layer has in-plane magnetic anisotropy (Y-axis direction) and the pinned magnetic layer has in-plane magnetic anisotropy in the X-axis direction (i.e., magnetization is pinned in the X-axis direction). At this time, the free magnetic layer is configured so that the magnetization is not oriented in a direction perpendicular to the plane.

[0100] FIG. 24 shows an example of the change in the magnetization state of the MTJ unit 31 with respect to the change in the distance between the MTJ unit 31 and the magnet 13 when the MTJ unit 31 is used as the above-described modified example, and an example of the change characteristics of the electrical resistance of the MTJ unit 31. When the distance between the MTJ unit 31 and the magnet 13 is long, the X component of the magnetic field acting on the MTJ unit 31 from the magnet 13 is in the positive direction, so the magnetization direction in the free magnetic layer is anti-parallel to the magnetization direction of the pinned magnetic layer (parallel to the X-axis direction in this case) and tilted toward the Y-axis. As the distance between the MTJ unit 31 and the magnet 13 becomes shorter and the X component of the magnetic field acting on the MTJ unit 31 becomes larger in the negative direction, the magnetization direction in the free magnetic layer passes through a state parallel to the Y-axis and then tilts to the same side as the magnetization direction of the pinned magnetic layer. As a result, as the distance between the MTJ portion 31 and the magnet 13 becomes shorter, a current flows more easily in the MTJ portion 31, in other words, the electrical resistance becomes smaller. Therefore, in this case, the magnitude of the electrical resistance of the MTJ section 31 also changes depending on the change in the distance from the magnet 13, and such a change in the electrical resistance of the MTJ section 31 can be detected as a change in voltage or a change in current, thereby detecting the position of the imaging lens 10 in a direction perpendicular to the reference optical axis Ax.

[0101] FIG. 25 shows the change characteristics of the X component of the magnetic field in the MTJ unit 31 and the change characteristics of the read voltage of the MTJ unit 31 when the MTJ unit 31 as the above-described modified example is displaced in the X-axis direction. As can be seen by referring to FIG. 21 above, the X component of the magnetic field acting on the MTJ section 31 from the magnet 13 is not dominant, and therefore the value on the vertical axis for the X component characteristics in FIG. 25 is smaller than that for the Z component characteristics in FIG. 23.

[0102] As shown in FIG. 26, the shape of the free magnetic layer in the MTJ section 31 can be elliptical. By making it elliptical, shape magnetic anisotropy is induced in the long axis direction. The aspect ratio of the ellipse is preferably about 1.5 to 3.0. If the aspect ratio is small, magnetic domains are likely to occur, while if the aspect ratio is large, the area becomes large. When detecting a change in the magnetic field in the vertical (Z-axis) direction, the direction of the major axis can be set regardless of the direction of the magnet 13. Furthermore, even if the shape of the free magnetic layer is a perfect circle instead of an ellipse, there is no problem with operation, except for the increased risk of magnetic domains occurring. Squares and rectangles are not desirable because the magnetization direction at the edges becomes non-uniform. The barrier layer and the pinned magnetic layer of the MTJ section 31 may have the same shape as the free magnetic layer, or may have any shape that is slightly larger than the free magnetic layer.

[0103] As shown in FIG. 27, a soft magnetic body 45 (yoke) can be provided for the magnetic sensor D1. Specifically, a soft magnetic body 45 is provided for each of the multiple magnetic sensors D1 formed in the image sensor 1. The soft magnetic body 45 may be provided on the light incident surface side of the image sensor 1, or on the opposite side to the light incident surface. The soft magnetic material 45 may be made of permalloy, for example.

[0104] By providing the soft magnetic body 45 for each magnetic sensor D1 as described above, it is possible to facilitate the flow of magnetic flux from the corresponding magnet 13 in each magnetic sensor, thereby improving the sensitivity of the magnetic sensor D1.

[0105] Although the above example shows the magnetic sensor D1 using the TMR sensor 30 (MTJ element) or the GMR element 32 formed in the wiring layer 1m, it is not essential to form them in the wiring layer 1m. For example, if the image sensor 1 has a configuration in which another semiconductor chip is attached to the side of the wiring layer 1m opposite to the side that contacts the semiconductor substrate 1s, it is possible to form the magnetic sensor D1 using the TMR sensor 30 or the GMR element 32 in the other semiconductor chip.

[0106] <4. Modifications> Here, the embodiment is not limited to the specific example described above, and various modified configurations can be adopted. For example, in the above example, the magnetic sensors D1 are provided at the four corners of the image sensor 1, but the magnetic sensors D1 may be arranged in other positions as shown in FIG. FIG. 28A shows an example in which the magnetic sensors D1 are arranged approximately in the center of each side of the image sensor 1. Fig. 28B shows an example in which only two of the four magnetic sensors D1 in the example of Fig. 28A are provided. Specifically, in the example of Fig. 28A, only one of the magnetic sensors D1 formed on each of the two sides in the column direction and only one of the magnetic sensors D1 formed on each of the two sides in the row direction are provided. As a result, similar to the previous example of FIG. 8, it is possible to detect the position of the imaging lens 10 in any direction perpendicular to the reference optical axis Ax.

[0107] 28A satisfies the above-mentioned conditions for enabling tilt detection. That is, the magnetic detection unit 1a in this case can be expressed as being configured to include two magnetic sensors D1 positioned opposite each other at both ends of the row direction of the image sensor 1, and two orthogonal magnetic sensors positioned opposite each other at both ends of the column direction of the image sensor 1.

[0108] In addition, in the above, an example was given in which the image sensor 1 is connected to the wiring board 7 by wire bonding as the imaging unit 51, but it is also possible to configure the image sensor 1 to be bump-connected to the wiring board 7B, as in the imaging unit 51B shown in Figure 29. In this case, the wiring board 7B has an opening H formed at a position where light from the imaging lens 10 is incident. In this case, the image sensor 1 is placed below the opening H so that light enters the effective pixel area through this opening H, and is electrically connected to the lower surface side of the wiring board 7B by bumps B, such as solder, formed on the light incident surface side. A protection member 16 is provided on the lower surface of the wiring board 7B to cover the sides of the image sensor 1. In this case, the wiring board 7B has the above-mentioned motion sensor 6, control unit 5, memory unit 21, and connector unit 22 formed on the lower surface.

[0109] Furthermore, although the above example shows that optical shake correction is performed by moving the imaging lens 10, the present technology can also be suitably applied to cases where optical shake correction is performed by moving the image sensor 1. In this case, the target of position detection based on the detection value of the magnetic sensor D1 is the image sensor 1, not the imaging lens 10.

[0110] Furthermore, although the above describes an example in which the image sensor and imaging device according to the present technology are applied to a portable information processing device such as a smartphone, the present technology can be widely and suitably applied to devices having an imaging function.

[0111] <5. Summary of embodiments> As described above, the image sensor (1 or 1A) of the embodiment includes a semiconductor substrate (1s) on which a plurality of pixels each having a photoelectric conversion element are arranged two-dimensionally, and a magnetic detection unit (1a, 1aA) that detects magnetic changes in response to changes in the relative position with an imaging lens (10) that guides light from a subject to the pixels. According to the above configuration, the magnetic detection unit is provided in the image sensor. This makes it possible to prevent the imaging unit from becoming larger in size due to the provision of the magnetic detection unit.

[0112] In addition, in the image sensor of the embodiment, the magnetic detection unit has an orthogonal direction magnetic sensor (magnetic sensor D1) that detects magnetic changes corresponding to changes in relative position in a direction perpendicular to the reference optical axis (Ax) of the imaging optical system including the imaging lens. The orthogonal magnetic sensor described above makes it possible to detect the position of the imaging lens or image sensor in the direction orthogonal to the reference optical axis, which changes as a result of optical shake correction. Therefore, when optical blur correction is performed by displacing the imaging lens or image sensor in a direction perpendicular to the reference optical axis, control can be performed to prevent the imaging lens or image sensor from sticking to the end position of the movable range of the optical blur correction based on the detection value of the orthogonal direction magnetic sensor.

[0113] Furthermore, in the image sensor of the embodiment, the magnetic detection unit has, as orthogonal direction magnetic sensors, a first direction magnetic sensor in which the change in detection value in response to a change in relative position in a first direction, which is a predetermined direction among directions orthogonal to the reference optical axis, is greater than the change in detection value in response to a change in relative position in a second direction, which is a direction orthogonal to the reference optical axis and orthogonal to the first direction, and a second direction magnetic sensor in which the change in detection value in response to a change in relative position in the second direction is greater than the change in detection value in response to a change in relative position in the first direction. The first direction magnetic sensor makes it possible to detect the position of the imaging lens or image sensor in a first direction, and the second direction magnetic sensor makes it possible to detect the position of the imaging lens or image sensor in a second direction. Therefore, based on the detection values ​​of these first and second direction magnetic sensors, it is possible to detect the position of the imaging lens or image sensor in any direction perpendicular to the reference optical axis. Therefore, when optical blur correction is performed by displacing the imaging lens or image sensor in any direction perpendicular to the reference optical axis, control can be performed to prevent the imaging lens or image sensor from sticking to the end position of the movable range of the optical blur correction based on the detection value of the orthogonal direction magnetic sensor.

[0114] Furthermore, in the image sensor of the embodiment, the magnetic detection unit is configured to have two orthogonal magnetic sensors positioned opposite each other at both ends of the row direction of the image sensor, and two orthogonal magnetic sensors positioned opposite each other at both ends of the column direction of the image sensor. As described above, the two orthogonal magnetic sensors positioned opposite both ends in the row direction make it possible to detect the tilt angle in a first tilt direction when the imaging lens or image sensor is tilted in the first tilt direction, and the two orthogonal magnetic sensors positioned opposite both ends in the column direction make it possible to detect the tilt angle in a second tilt direction when the imaging lens or image sensor is tilted in a second tilt direction perpendicular to the first tilt direction. Therefore, when optical blur correction is performed by not only displacing the imaging lens or image sensor in any direction perpendicular to the reference optical axis but also tilting it in any tilt direction, it is possible to detect the position and tilt angle of the imaging lens or image sensor in the direction perpendicular to the reference optical axis.

[0115] In the image sensor of the embodiment, the magnetic detection unit has orthogonal magnetic sensors at the four corners of the image sensor. This makes it possible to detect the position of the imaging lens in a direction perpendicular to the reference optical axis and the tilt angle in cases where optical shake correction is performed by moving the imaging lens and magnets are provided at the four corners of the lens holding part that moves together with the imaging lens.

[0116] Furthermore, in the image sensor of the embodiment, the magnetic detection unit has orthogonal magnetic sensors at approximately the center of each side of the image sensor. This makes it possible to detect the position of the imaging lens in a direction perpendicular to the reference optical axis and the tilt angle in cases where optical shake correction is performed by moving the imaging lens and magnets are provided approximately in the center of each side of the lens holding part that moves together with the imaging lens.

[0117] Furthermore, in the image sensor of the embodiment, a wiring layer (1m) is formed on the surface opposite to the light receiving surface of the semiconductor substrate, and the orthogonal magnetic sensor is formed in the wiring layer. This makes it possible to form the orthogonal magnetic sensor in the process of forming the wiring layer on the semiconductor substrate. Since the orthogonal magnetic sensor can be formed by utilizing the process for forming the wiring and vias for the wiring layer, the cost for forming the orthogonal magnetic sensor can be reduced.

[0118] In addition, in the image sensor of the embodiment, the magnetic detection unit (1aA) has an axial magnetic sensor (coil-type sensor D2) composed of a coil formed on the surface of the semiconductor substrate on which light from the subject is incident. As described above, the axial magnetic sensor, which is a coil provided on the image sensor, makes it possible to detect induced electromotive forces based on the magnetic field generated by the focus coil, which is provided so as to be freely displaceable in the direction of the reference optical axis together with the imaging lens. This induced electromotive force tends to become larger as the imaging lens approaches the image sensor, so the position of the imaging lens in the direction of the reference optical axis can be detected based on the detection value by the axial magnetic sensor. One possible method for detecting the axial position of the imaging lens is to provide a magnet that is linked to the axial displacement of the imaging lens. However, the above configuration makes it unnecessary to provide such a magnet, thereby enabling the imaging optical system to be made smaller and lighter. In addition, by combining it with an orthogonal magnetic sensor, it is possible to detect the position and orientation in a total of five axes: directions orthogonal to the reference optical axis (two axes), tilt directions (two axes), and the axial direction of the reference optical axis (one axis).

[0119] Furthermore, in the image sensor of the embodiment, the coils in the axial magnetic sensor are arranged in the outer peripheral region of the effective pixel region. In the peripheral area of ​​the effective pixel area, there is generally a dead space as a keep-out zone. According to the above configuration, a coil serving as an axial magnetic sensor can be formed in such a keepout zone, thereby preventing the surface size of the image sensor from increasing due to the formation of the axial magnetic sensor.

[0120] Furthermore, in the image sensor of the embodiment, the orthogonal magnetic sensor has an MTJ element (MTJ portion 31) as a magnetoresistive effect element. The MTJ element has a larger change in electrical resistance due to the magnetoresistive effect than conventional magnetoresistive elements such as Hall elements, and can therefore improve the accuracy of magnetic detection. Furthermore, the MTJ element can be produced by a semiconductor manufacturing process, which allows for the size of the magnetic sensor to be reduced.

[0121] In the image sensor of the embodiment, the orthogonal magnetic sensor is composed of a plurality of MTJ elements. This makes it possible to improve the noise resistance of the orthogonal magnetic sensor. Therefore, the accuracy of magnetic detection by the orthogonal magnetic sensor can be improved.

[0122] Furthermore, in the image sensor of the embodiment, the orthogonal magnetic sensor has a GMR element (32) as a magnetoresistive effect element. The GMR element has a larger change in electrical resistance due to the magnetoresistance effect than conventional magnetoresistance effect elements such as Hall elements, and can therefore improve the accuracy of magnetic detection. Furthermore, the GMR element can be produced using a semiconductor manufacturing process, which allows for the size of the magnetic sensor to be reduced.

[0123] Furthermore, in the image sensor of the embodiment, the magnetic detection unit has a plurality of orthogonal magnetic sensors, and each orthogonal magnetic sensor is provided with a soft magnetic body (45). The soft magnetic material provided for each orthogonal magnetic sensor makes it possible to facilitate the flow of magnetic flux from a magnet provided for detecting the position of the imaging lens or image sensor in each orthogonal magnetic sensor. Therefore, the sensitivity of the orthogonal magnetic sensor can be improved, and the accuracy of detecting the relative position with respect to the imaging lens can be improved.

[0124] In addition, an imaging device (same as 50) as an embodiment includes an image sensor having a semiconductor substrate on which multiple pixels each having a photoelectric conversion element are arranged two-dimensionally, and a magnetic detection unit that detects magnetic changes corresponding to changes in the relative position with respect to an imaging lens that guides light from a subject to the pixels, and an image signal processing unit (same as 52) that performs signal processing on the captured image signal obtained by the image sensor. With such an imaging device, it is possible to obtain the same functions and effects as the image sensor of the above embodiment.

[0125] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0126] <6. This technology> The present technology can also be configured as follows. (1) a semiconductor substrate on which a plurality of pixels each having a photoelectric conversion element are arranged two-dimensionally; a magnetic detection unit that detects a magnetic change corresponding to a change in the relative position with respect to an imaging lens that guides light from a subject to the pixels; Image sensor. (2) The magnetic detection unit an orthogonal magnetic sensor that detects a magnetic change corresponding to a change in the relative position in a direction orthogonal to a reference optical axis of the imaging optical system including the imaging lens; The image sensor according to (1) above. (3) The magnetic detection unit includes the orthogonal magnetic sensor, a first direction magnetic sensor in which a change in a detection value in response to a change in the relative position in a first direction, which is a predetermined direction among directions orthogonal to the reference optical axis, is larger than a change in a detection value in response to a change in the relative position in a second direction, which is a direction orthogonal to the reference optical axis and orthogonal to the first direction; a second direction magnetic sensor in which a change in detection value in response to a change in the relative position in the second direction is larger than a change in detection value in response to a change in the relative position in the first direction; The image sensor according to (2) above. (4) The magnetic detection unit The image sensor is configured to have two orthogonal magnetic sensors positioned opposite each other at both ends in the row direction, and two orthogonal magnetic sensors positioned opposite each other at both ends in the column direction. The image sensor according to (2) or (3) above. (5) The magnetic detection unit The orthogonal magnetic sensors are provided at the four corners of the image sensor. The image sensor according to (4) above. (6) The magnetic detection unit The image sensor has the orthogonal magnetic sensors at the approximate centers of the sides. The image sensor according to (4) above. (7) a wiring layer is formed on the surface of the semiconductor substrate opposite to the light-receiving surface, The orthogonal magnetic sensor is formed in the wiring layer. The image sensor according to any one of (2) to (6) above. (8) The magnetic detection unit The semiconductor substrate has an axial magnetic sensor formed by a coil formed on the surface on which light from the subject is incident. The image sensor according to any one of (1) to (7). (9) The coil in the axial magnetic sensor is disposed in the outer peripheral region of the effective pixel region. The image sensor according to (8) above. (10) The orthogonal magnetic sensor has an MTJ element as a magnetoresistive element. The image sensor according to any one of (2) to (7) above. (11) The orthogonal magnetic sensor is composed of a plurality of the MTJ elements. The image sensor according to (10) above. (12) The orthogonal magnetic sensor has a GMR element as a magnetoresistive element. The image sensor according to any one of (2) to (7) above. (13) the magnetic detection unit includes a plurality of the orthogonal magnetic sensors, A soft magnetic body is provided for each of the orthogonal magnetic sensors. The image sensor according to any one of (2) to (7) and (10) to (12). (14) a semiconductor substrate on which a plurality of pixels each having a photoelectric conversion element are arranged two-dimensionally; a magnetic detection unit that detects a magnetic change corresponding to a change in relative position with respect to an imaging lens that guides light from a subject to the pixels; an image sensor having an image signal processing unit that performs signal processing on the captured image signal obtained by the image sensor; Imaging device. [Explanation of symbols]

[0127] 50 Imaging device 51,51B Imaging unit 52 Image signal processing section 1.1A image sensor 1a, 1aA Magnetic detection unit 1s semiconductor substrate 1m wiring layer D1, D1a, D1b, D1c, D1d magnetic sensors 4 Image stabilization coil 4a coil 5,5A control unit 6. Motion Sensor 7,7B Wiring board 8. Adhesive 9 Spacers 10 Imaging lens 11 Lens holder 12 Lens unit holder 12a opening 13, 13a, 13b, 13c, 13d Magnets 14 IR cut filter 15 Shield cover 16 Protective materials W Bonding Wire Ax Reference optical axis 20 Mobile Unit 21 Memory section 22 Connector part D2 Coil Type Sensor 30 TMR sensor 31 MTJ Department 31' MTJ membrane 32 GMR element 35,38 Wiring 36 First Contact 37 Second Contact 39 Hard Mask 40 Protective film 45 Soft magnetic material

Claims

1. a semiconductor substrate on which a plurality of pixels each having a photoelectric conversion element are arranged two-dimensionally; a magnetic detection unit that detects magnetic changes according to changes in the relative position with respect to an imaging lens that guides light from a subject to the pixels; a wiring layer is formed on the surface of the semiconductor substrate opposite to the light-receiving surface, The magnetic detection unit an orthogonal direction magnetic sensor that detects a magnetic change corresponding to a change in the relative position in a direction orthogonal to a reference optical axis of an imaging optical system including the imaging lens; The orthogonal magnetic sensor is formed in the wiring layer. Image sensor.

2. The magnetic detection unit includes the orthogonal magnetic sensor, a first direction magnetic sensor in which a change in a detection value in response to a change in the relative position in a first direction, which is a predetermined direction among directions orthogonal to the reference optical axis, is larger than a change in a detection value in response to a change in the relative position in a second direction, which is a direction orthogonal to the reference optical axis and orthogonal to the first direction; a second direction magnetic sensor in which a change in detection value in response to a change in the relative position in the second direction is larger than a change in detection value in response to a change in the relative position in the first direction; The image sensor of claim 1 .

3. The magnetic detection unit The image sensor is configured to have two orthogonal magnetic sensors positioned opposite each other at both ends in the row direction, and two orthogonal magnetic sensors positioned opposite each other at both ends in the column direction. The image sensor of claim 1 .

4. The magnetic detection unit The orthogonal magnetic sensors are provided at the four corners of the image sensor.

4. The image sensor according to claim 3.

5. The magnetic detection unit The image sensor has the orthogonal magnetic sensors at the approximate centers of the sides.

4. The image sensor according to claim 3.

6. The magnetic detection unit The semiconductor substrate has an axial magnetic sensor formed by a coil formed on the surface on which light from the subject is incident. The image sensor of claim 1 .

7. The coil in the axial magnetic sensor is disposed in the outer peripheral region of the effective pixel region.

7. The image sensor according to claim 6.

8. The orthogonal magnetic sensor has an MTJ element as a magnetoresistive element. The image sensor of claim 1 .

9. The orthogonal magnetic sensor is composed of a plurality of the MTJ elements.

9. The image sensor according to claim 8.

10. The orthogonal magnetic sensor has a GMR element as a magnetoresistive element. The image sensor of claim 1 .

11. the magnetic detection unit includes a plurality of the orthogonal magnetic sensors, A soft magnetic body is provided for each of the orthogonal magnetic sensors. The image sensor of claim 1 .

12. a semiconductor substrate on which a plurality of pixels each having a photoelectric conversion element are arranged two-dimensionally; a magnetic detection unit that detects a magnetic change corresponding to a change in relative position with respect to an imaging lens that guides light from a subject to the pixels; an image sensor having an image signal processing unit that processes a captured image signal obtained by the image sensor, In the image sensor, a wiring layer is formed on the surface of the semiconductor substrate opposite to the light-receiving surface, The magnetic detection unit an orthogonal direction magnetic sensor that detects a magnetic change corresponding to a change in the relative position in a direction orthogonal to a reference optical axis of an imaging optical system including the imaging lens; The orthogonal magnetic sensor is formed in the wiring layer. Imaging device.

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