WO2017119177A1 - Solid-state image pickup element, method for driving solid-state image pickup element, and electronic apparatus - Google Patents

Abstract

Disclosed is a solid-state image pickup element that is provided with: a first semiconductor chip having a pixel array unit configured by disposing unit pixels that generate electric signals corresponding to incident light; a second semiconductor chip, which is laminated on the first semiconductor chip, and which has a signal processing unit that performs predetermined signal processing with respect to the electric signals generated by the unit pixels of the pixel array unit; and a signal transmission unit that performs, in a pixel array unit region, electric signal transmission between the first semiconductor chip and the second semiconductor chip in a non-contact manner.

Description

Solid-state imaging device, driving method of solid-state imaging device, and electronic device

The present disclosure relates to a solid-state imaging device, a driving method of the solid-state imaging device, and an electronic device.

Solid-state image sensors, especially CMOS (Complementary Metal Oxide Semiconductor) image sensors, are used in electronic devices such as mobile phones, digital still cameras, single-lens reflex cameras, camcorders, and surveillance cameras, taking advantage of low power consumption and high speed. It is becoming widely installed. Recently, high-performance, high-quality image sensors that are on-chip together with the pixel array portion (pixel portion) are also appearing in functional circuit blocks such as image processing.

In recent years, the development of a stacked solid-state imaging device in which a pixel portion and a circuit portion are formed on separate semiconductor chips (semiconductor substrates) and these semiconductor chips are stacked has been earnestly advanced. This multilayer solid-state imaging device has an advantage that various functions can be freely incorporated while achieving miniaturization, high image quality, high speed, and the like.

In a multilayer solid-state imaging device, when transmitting a signal between a semiconductor chip on the pixel unit side and a semiconductor chip on the circuit unit side, a micropad is formed corresponding to the position of both chips, and the microbumps are used to connect the two chips. Are electrically connected (for example, see Patent Document 1). In addition, a technique has been reported in which signals are transmitted (transmitted) between both chips by magnetic coupling in the peripheral region of the pixel array unit (see, for example, Non-Patent Document 1).

JP 2006-49361 A

However, in the conductor connection by the bump as in the prior art described in Patent Document 1, a high level of processing technology is required, and the image quality, yield, and manufacturing due to variations in connection portions and the occurrence of voids are reduced. There are problems such as an increase in cost. In addition, in the TSV (Through Silicon Via) connection, it is necessary to penetrate the junction surface and form it deep in the semiconductor element. Moreover, since there is a limit to the pitch of bumps that can be formed, it is difficult to reduce the pitch.

On the other hand, in the conventional technique described in Non-Patent Document 1, a pixel signal read through a signal line is transmitted for each pixel column in the peripheral region of the pixel array unit. Therefore, an inductor (coil) for magnetic coupling is formed in a limited and narrow region around the pixel array portion, and the layout occupancy of the inductor cannot be secured sufficiently, resulting in poor transmission efficiency.

Therefore, the present disclosure provides a solid-state imaging device capable of performing signal transmission with high transmission efficiency between stacked semiconductor chips while solving the problem of conductor connection, a driving method of the solid-state imaging device, and An object is to provide an electronic apparatus having the solid-state imaging element.

In order to achieve the above object, a solid-state imaging device of the present disclosure is provided.
A first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
A second semiconductor chip having a signal processing unit that is stacked on the first semiconductor chip and that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
In the region of the pixel array unit, a signal transmission unit that transmits electrical signals in a non-contact manner between the first semiconductor chip and the second semiconductor chip;
Is provided. In addition, an electronic apparatus according to the present disclosure for achieving the above object includes the solid-state imaging device having the above configuration.

In order to achieve the above object, a method for driving a solid-state imaging device of the present disclosure includes
A first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
A second semiconductor chip having a signal processing unit that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
When driving a solid-state imaging device that is laminated,
In the region of the pixel array portion, electrical signals are transmitted in a non-contact manner between the first semiconductor chip and the second semiconductor chip.

According to the present disclosure, by transmitting signals between the stacked chips in the region of the pixel array unit, it is possible to sufficiently secure the layout occupancy of the elements constituting the signal transmission unit. Thus, signal transmission with high transmission efficiency can be performed between the stacked semiconductor chips.

It should be noted that the effect described here is not necessarily limited, and may be any effect described in the present specification. Moreover, the effect described in this specification is an illustration to the last, Comprising: It is not limited to this, There may be an additional effect.

FIG. 1 is a schematic configuration diagram illustrating an example of a basic configuration of a stacked solid-state imaging device. FIG. 2 is a block diagram illustrating an overall configuration example of the solid-state imaging device according to the first embodiment. FIG. 3 is a circuit diagram illustrating an example of a circuit configuration of a unit pixel and a voltage / current converter in the solid-state imaging device according to the first embodiment. FIG. 4A is a circuit diagram illustrating an example of a circuit configuration of a signal detection unit in the solid-state imaging device according to the first embodiment, and FIG. 4B is a block diagram illustrating an example of a circuit configuration of an AD converter. FIG. 5 is a timing waveform diagram for explaining an operation example of the solid-state imaging device according to the first embodiment. FIG. 6 is a diagram illustrating an example of the layout of the inductor on the first semiconductor chip side and the inductor on the second semiconductor chip side in the solid-state imaging device according to the first embodiment. FIG. 7 is a diagram illustrating another example of the layout of the inductor on the first semiconductor chip side and the inductor on the second semiconductor chip side in the solid-state imaging device according to the first embodiment. FIG. 8 is a block diagram illustrating an example of the overall configuration of the solid-state imaging device according to the second embodiment. FIG. 9 is a circuit diagram illustrating an example of a circuit configuration of a unit pixel on the first semiconductor chip side and a signal detection unit on the second semiconductor chip side in the solid-state imaging device according to the second embodiment. FIG. 10 is a timing waveform diagram for explaining an operation example of the solid-state imaging device according to the second embodiment. FIG. 11 is a diagram illustrating an example of the layout of the inductor on the first semiconductor chip side and the inductor on the second semiconductor chip side in the solid-state imaging device according to the fourth embodiment. FIG. 12 is a principle diagram of a transmission method using electrostatic coupling. FIG. 13 is a block diagram illustrating a configuration of an imaging apparatus that is an example of the electronic apparatus of the present disclosure.

Hereinafter, modes for carrying out the technology of the present disclosure (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings. The technology of the present disclosure is not limited to the embodiment, and various numerical values and materials in the embodiment are examples. In the following description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted. The description will be given in the following order.
1. 1. Description of the solid-state imaging device of the present disclosure, a driving method thereof, and an electronic device in general 2. Stacked solid-state imaging device First embodiment (an example where the signal to be transmitted is an analog signal)
4). Second Embodiment (Example in which a transmission target signal is a digital signal)
5). Modification 6 Electronic device of the present disclosure (example of imaging device)

<Description of Solid-State Imaging Device of the Present Disclosure, its Driving Method, and Electronic Device>
In the solid-state imaging device, the driving method thereof, and the electronic apparatus according to the present disclosure, an electric signal is transmitted between the first semiconductor chip and the second semiconductor chip by magnetic (magnetic field) coupling between the first semiconductor chip and the second semiconductor chip. It can be configured to perform transmission. However, the signal transmission unit is not limited to a transmission method using magnetic coupling, and may be another non-contact transmission method, for example, a transmission method using electrostatic coupling.

In the solid-state imaging device of the present disclosure including the preferable configuration described above, the driving method thereof, and the electronic device, the unit pixel is preferably a back-illuminated pixel. Here, the “backside illuminated pixel” refers to a pixel structure that takes in incident light from the opposite side, that is, the back side when the side on which the wiring layer is disposed is the front side. However, the unit pixel is not limited to the back-illuminated pixel, and may be a front-illuminated pixel. Here, the “front-illuminated pixel” refers to a pixel structure that captures incident light from the surface side where the wiring layer is disposed.

Furthermore, in the solid-state imaging device of the present disclosure including the preferable configuration described above, the driving method thereof, and the electronic device, the electrical signal transmitted by the signal transmission unit may be an analog signal.

Alternatively, in the solid-state imaging device of the present disclosure including the preferable configuration described above, a driving method thereof, and an electronic device, the electrical signal transmitted by the signal transmission unit may be a digital signal. At this time, the unit pixel has a function of converting an electrical signal corresponding to incident light into a digital signal.

Further, in the solid-state imaging device of the present disclosure including the preferable configuration described above, a driving method thereof, and an electronic device, one or more inductors in the signal transmission unit are provided for one pixel column of the pixel array unit. It can be set as the structure currently provided. Alternatively, the inductor in the signal transmission unit may be formed along each pixel column of the pixel array unit.

Further, in the solid-state imaging device of the present disclosure including the preferable configuration described above, a driving method thereof, and an electronic apparatus, one inductor for the signal transmission unit is provided for one unit pixel of the pixel array unit, or One pixel unit composed of a plurality of unit pixels can be provided. Alternatively, the inductor in the signal transmission unit may be formed on the substrate surface opposite to the light-receiving side substrate surface of the back-illuminated pixel of the first semiconductor chip.

<Stacked solid-state image sensor>
First, a stacked solid-state imaging device to which the technology of the present disclosure is applied will be described. An example of a basic configuration of a stacked solid-state imaging device is shown in FIG. The stacked solid-state imaging device 10 includes a first semiconductor chip (semiconductor substrate) 11 and a second semiconductor chip 12. For example, the first semiconductor chip 11 is an upper chip and the second semiconductor chip 12 is a lower chip. It is a structure laminated as a chip (so-called laminated structure).

In this stacked structure, the upper first semiconductor chip 11 is formed by arranging unit pixels (hereinafter simply referred to as “pixels”) 20 including photoelectric conversion elements in a two-dimensional matrix (matrix). This is a pixel chip in which a pixel array unit (pixel unit) 13 is formed. In the stacked solid-state imaging device 10 according to this example, the first semiconductor chip 11 is also equipped with a vertical scanning unit 14 that scans each pixel 20 of the pixel array unit 13 in the vertical direction (column direction). It has become. Note that the vertical scanning unit 14 may be mounted on the second semiconductor chip 12 side. It is arbitrary whether the vertical scanning unit 14 is mounted on the first semiconductor chip 11 side or the second semiconductor chip 12 side.

The lower second semiconductor chip 12 includes a signal processing unit 15 and a horizontal scanning unit 16 that perform various processes related to pixel signals read from each pixel 20 of the pixel array unit 13 formed on the first semiconductor chip 11. The circuit chip is formed with a circuit portion. The signal processing unit 15 performs predetermined signal processing including analog-digital conversion processing on the pixel signal read from each pixel 20 of the pixel array unit 13. Details of the signal processing unit 15 will be described later. The horizontal scanning unit 16 scans the pixel signals in units of rows subjected to signal processing by the signal processing unit 15 in the horizontal direction (row direction), and performs processing of reading out in a predetermined order.

Since the above-described stacked-type (laminated structure) solid-state imaging device 10 needs only to be large enough to form the pixel array section 13 as the first semiconductor chip 11, the size of the first semiconductor chip 11, and thus, The overall size of the solid-state imaging device 10 can be reduced. Furthermore, since a process suitable for the creation of the pixel 20 can be applied to the first semiconductor chip 11 and a process suitable for the creation of a circuit can be applied to the second semiconductor chip 12, respectively, in manufacturing the stacked solid-state imaging device 10, There is also an advantage that the process can be optimized.

<First Embodiment>
The solid-state imaging device according to the first embodiment is premised on a stacked solid-state imaging device formed by stacking the first semiconductor chip 11 and the second semiconductor chip 12 described above. In the solid-state imaging device 10 according to the first embodiment, in the region of the pixel array unit 13, electrical signals are transmitted in a non-contact manner between the first semiconductor chip 11 and the second semiconductor chip 12, and The signal to be transmitted is an analog signal.

Examples of non-contact transmission methods include a transmission method using magnetic (magnetic field) coupling and a transmission method using electrostatic coupling. In the present embodiment, an electrical signal is transmitted between the first semiconductor chip 11 and the second semiconductor chip 12 by using a transmission method using magnetic coupling of inductors. However, the transmission method is not limited to magnetic coupling.

FIG. 2 is a block diagram illustrating an example of the overall configuration of the solid-state imaging device (stacked solid-state imaging device) according to the first embodiment. FIG. 2 mainly shows only functional units related to the technology of the present disclosure.

(First semiconductor chip)
In the first semiconductor chip 11, unit pixels 20 are arranged in a two-dimensional matrix (matrix) of m pixel rows and n pixel columns to form a pixel array unit 13. For this two-dimensional matrix pixel arrangement, pixel drive lines 31 (31 ₁ to 31 _m ) are wired along the row direction for each pixel row, and signal lines 32 (32 ₁ to 32 _n ) are provided for each pixel column. Are wired along the column direction. In FIG. 2, the pixel drive line 31 is illustrated as one wiring, but is not limited to one.

On one side of the pixel array unit 13 in the row direction, a vertical scanning unit 14 is disposed. The vertical scanning unit 14 outputs a drive signal for driving when reading a signal from the unit pixel 20 to the pixel drive lines 31 ₁ to 31 _m . In other words, one end of each of the pixel drive lines 31 _{_ 1} to 31 _{_m} is connected to each output end corresponding to each row of the vertical scanning unit 14, and the drive signal output from these output ends is output for each pixel row. The data is transmitted to the unit pixel 20.

The vertical scanning unit 14 includes a shift register, an address decoder, and the like, and drives each pixel 20 of the pixel array unit 13 at the same time or in units of rows. Although the vertical scanning unit 14 is not shown in detail with respect to its specific configuration, the vertical scanning unit 14 generally has two scanning systems, a reading scanning system and a sweeping scanning system. The readout scanning system selectively scans the unit pixels 20 in the pixel array unit 13 in order in units of rows in order to read out signals from the unit pixels 20. A signal read from the unit pixel 20 is an analog signal. The sweep-out scanning system performs sweep-out scanning with respect to the readout row on which readout scanning is performed by the readout scanning system, preceding the readout scanning by a time corresponding to the shutter speed.

By the sweep scanning by the sweep scanning system, unnecessary charges are swept out from the photoelectric conversion element of the unit pixel 20 in the readout row, thereby resetting the photoelectric conversion element. A so-called electronic shutter operation is performed by sweeping (resetting) unnecessary charges by the sweep scanning system. Here, the electronic shutter operation refers to an operation in which the photoelectric charge of the photoelectric conversion element is discarded and a new exposure is started (photocharge accumulation is started).

The signal read out by the readout operation by the readout scanning system corresponds to the amount of light received after the immediately preceding readout operation or electronic shutter operation. A period from the read timing by the immediately preceding read operation or the sweep timing by the electronic shutter operation to the read timing by the current read operation is the photo charge exposure period in the unit pixel 20.

In the region of the pixel array section 13, a constant current source 33 is disposed on each one end side of the signal lines (column signal lines / vertical signal lines) 32 ₁ to 32 _n . The current source 33 has one end connected to one end of each of the signal lines 32 ₁ to 32 _{n and} the other end connected to a fixed potential (for example, ground), and supplies current to the signal lines 32 ₁ to 32 _n . A voltage / current converter 41 and an inductor (coil) 42 are disposed at each other end of the signal lines 32 ₁ to 32 _n . That is, the voltage / current converter 41 and the inductor 42 are provided for each pixel column of the pixel array unit 13.

Voltage-current conversion unit 41 is connected the input end to the other end of each of the signal lines 32 ₁ ~ 32 _n, the signal lines 32 ₁ ~ 32 _n voltage value of which varies according to the amount of incident light to the unit pixel 20 Is converted into a current value. The inductor 42 has one end connected to the output end of the voltage / current converter 41 and the other end connected to a node of a fixed potential, and generates an electromotive force according to a change in the current value output from the voltage / current converter 41. appear.

(Second semiconductor chip)
The second semiconductor chip 12 is provided with an inductor 51 at a position corresponding to the inductor 42 provided for each pixel column in the first semiconductor chip 11. Then, by laminating the first semiconductor chip 11 and the second semiconductor chip 12, the inductor 42 and the inductor 51 are also laminated. As a result, the electromotive force generated in the inductor 42 on the first semiconductor chip 11 side is transmitted to the inductor 51 on the second semiconductor chip 12 side that is disposed in proximity by the mutual induction action. That is, the inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side perform signal transmission between the first semiconductor chip 11 and the second semiconductor chip 12 in a contactless manner. Is configured.

The second semiconductor chip 12 further includes a signal detection unit 52, an analog-digital converter (hereinafter sometimes referred to as “AD converter”) 53, a memory 54, and a column selection corresponding to the inductor 51. A switch 55 is provided. That is, the signal detection unit 52, the AD converter 53, the memory 54, and the column selection switch 55 are provided for each pixel column of the pixel array unit 13 on the first semiconductor chip 11 side together with the inductor 51.

The inductor 51, the signal detection unit 52, the AD converter 53, the memory 54, and the column selection switch 55 are used for pixel signals read from the pixels 20 of the pixel array unit 13 on the first semiconductor chip 11 side. A signal processing unit 15 that performs predetermined signal processing including analog-digital conversion processing is configured. The second semiconductor chip 12 is further provided with a horizontal scanning unit 16 that performs scanning in the horizontal direction on the pixel signals for each row processed by the signal processing unit 15 and reads them in a predetermined order. The horizontal scanning unit 16 includes a shift register, an address decoder, and the like.

The inductor 51 on the second semiconductor chip 12 side generates a voltage equivalent to the electromotive force generated by the inductor 42 on the first semiconductor chip 11 side. The signal detection unit 52 detects a voltage change of the inductor 51, converts it into an analog pixel signal, and supplies it to the AD converter 53. The AD converter 53 converts the analog pixel signal into a digital pixel signal. As the AD converter 53, a well-known AD converter can be used.

As a known AD converter, a single slope type AD converter, a successive approximation type AD converter, or a delta-sigma modulation type (ΔΣ modulation type) AD converter can be exemplified. Further, the AD converter 53 may include a gray code counter. However, the AD converter 53 is not limited to these, and an AD converter such as a flash type, a half flash type, a sublens type, a pipeline type, a bit per stage type, a magnitude amplifier type, etc. Can also be mentioned.

The memory 54 stores the digital pixel signal that has been analog-digital converted by the AD converter 53. The column selection switch 55 reads the digital pixel signal stored in the memory 54 to the signal output line 56 when turned on under scanning by the horizontal scanning unit 16. The read digital pixel signal is subjected to final signal processing as necessary. Thereafter, the digital image data is output to the second semiconductor chip 12.

(Unit pixel and voltage-current converter)
An example of the circuit configuration of the unit pixel 20 and the voltage / current converter 41 is shown in FIG. The unit pixel 20 according to this example includes, for example, a photodiode (PD) 21 as a photoelectric conversion element. As shown in FIG. 3, the unit pixel 20 includes a transfer transistor 22, a reset transistor 23, an amplification transistor 24, and a selection transistor 25 in addition to the photodiode 21.

Here, for example, N-type MOSFETs are used as the four transistors of the transfer transistor 22, the reset transistor 23, the amplification transistor 24, and the selection transistor 25. However, the combination of the conductivity types of the four transistors 22 to 25 illustrated here is merely an example, and is not limited to these combinations.

For this unit pixel 20, a plurality of drive lines 311, 312, and 313 are wired in common to the pixels in the same pixel row as the pixel drive lines 31 (31 ₁ to 31 _m ) described above. The plurality of drive lines 311, 312, 313 are connected to the output end corresponding to each pixel row of the vertical scanning unit 14 (see FIG. 2) in units of pixel rows. The vertical scanning unit 14 appropriately outputs a transfer signal TRX, a reset signal RST, and a selection signal SEL to the plurality of drive lines 311, 312, 313.

The photodiode 21 has an anode electrode connected to a low-potential-side power source (for example, ground), and photoelectrically converts received light into photocharge (here, photoelectrons) having a charge amount corresponding to the amount of light. Accumulate charge. The cathode electrode of the photodiode 21 is electrically connected to the gate electrode of the amplification transistor 24 through the transfer transistor 22. A region electrically connected to the gate electrode of the amplification transistor 24 is a floating diffusion FD as a charge-voltage conversion unit (charge detection unit) that converts charges into voltage.

The transfer transistor 22 is connected between the cathode electrode of the photodiode 21 and the floating diffusion FD. A transfer signal TRX that activates a high level (for example, V _dd level) is applied to the gate electrode of the transfer transistor 22 from the vertical scanning unit 14 through the drive line 311. When the transfer transistor 22 is turned on in response to the transfer signal TRX, it is photoelectrically converted by the photodiode 21 and transfers the accumulated photocharge to the floating diffusion FD.

The reset transistor 23 has a drain electrode connected to a node (power supply line) of the power supply potential _Vdd , and a source electrode connected to the floating diffusion FD. A reset signal RST that activates a high level is applied to the gate electrode of the reset transistor 23 from the vertical scanning unit 14 through the drive line 312. Reset transistor 23 becomes conductive in response to a reset signal RST, which resets the floating diffusion FD by discarding the charge of the floating diffusion FD to a node of the power supply potential V _dd.

The amplification transistor 24 has a gate electrode connected to the floating diffusion FD and a drain electrode connected to the node of the power supply potential _Vdd . The amplification transistor 24 serves as an input section of a source follower that is a readout circuit that reads a signal obtained by photoelectric conversion at the photodiode 21. That is, the amplifying transistor 24 forms a source follower with the current source 33 connected to the end of the signal line 32 by connecting the source electrode to the signal line 32 via the selection transistor 25.

The selection transistor 25 has, for example, a drain electrode connected to the source electrode of the amplification transistor 24 and a source electrode connected to the signal line 32. A selection signal SEL that activates a high level is supplied from the vertical scanning unit 14 to the gate electrode of the selection transistor 25 through the drive line 313. The selection transistor 25 becomes conductive in response to the selection signal SEL, and transmits the signal output from the amplification transistor 24 to the signal line 32 with the unit pixel 20 selected.

Note that the selection transistor 25 may have a circuit configuration connected between the node of the power supply potential _Vdd and the drain electrode of the amplification transistor 24. In this example, as a pixel circuit of the unit pixel 20, a 4Tr configuration including the transfer transistor 22, the reset transistor 23, the amplification transistor 24, and the selection transistor 25, that is, four transistors (Tr) is given as an example. However, it is not limited to this. For example, the selection transistor 25 may be omitted, and a 3Tr configuration in which the amplification transistor 24 has the function of the selection transistor 25 may be used, or a configuration in which the number of transistors is increased as necessary.

As shown in FIG. 3, the voltage / current converter 41 includes an operational amplifier 411, a MOS transistor 412, and a resistance element 413. The operational amplifier 411 has a non-inverting (+) input terminal connected to the signal line 32. The MOS transistor 412 has a gate electrode connected to the output terminal of the operational amplifier 411 and a source electrode connected to the inverting (−) input terminal of the operational amplifier 411. One end of the resistance element 413 is connected to the source electrode of the MOS transistor 412, and the other end is connected to a low potential side power source (for example, ground).

Here, the drain electrode of the MOS transistor 412 serves as the output terminal of the voltage-current converter 41. The inductor 42 has one end connected to the output end of the voltage-current converter 41, that is, the drain electrode of the MOS transistor 412, and the other end connected to a node (power supply line) of a fixed potential, for example, the power supply potential _Vdd . .

In the voltage-current converter 41 having the above configuration, the current I flowing from the inductor 42 to the MOS transistor 412 flows to the ground through the resistance element 413. Therefore, when the resistance value of the resistance element 413 is R, the voltage across the resistance element 413 is Becomes I × R. The operational amplifier 411 is configured so that the voltage I × R between both ends of the resistance element 413 and the non-inverting (+) input voltage of the operational amplifier 411 become equal due to an imaginary short in which the potential difference between the two input terminals becomes zero. Operate. As a result, the current I flowing through the MOS transistor 412 changes so that the voltage of the signal line 32 that changes according to the amount of incident light of the unit pixel 20 becomes the voltage I × R across the resistor 413. At this time, the current flowing through the inductor 42 is also I.

By converting the voltage of the signal line 32 into the current I, an induced electromotive force V corresponding to the pixel signal is generated in the inductor 42 as shown in the following equation (1).
V = −L (ΔV / ΔI) (1)
Here, L is the inductance of the inductor 42, and L = μS / l × N ² . Further, μ is the magnetic permeability, S is the cross-sectional area of the coil, l is the length of the coil, and N is the number of turns of the coil.

(Signal detection unit and AD converter)
An example of the circuit configuration of the signal detector 52 is shown in FIG. 4A, and an example of the circuit configuration of the AD converter 53 is shown in FIG. 4B. As illustrated in FIG. 4A, the signal detection unit 52 has a rectifier circuit configuration including a diode 521 and a capacitor 522. The diode 521 has an anode electrode connected to one end of the inductor 51 and a cathode electrode connected to one electrode of the capacitor 522. The other electrode of the capacitive element 522 is connected to the other end of the inductor 51.

In this example, a case where a single slope AD converter is used as the AD converter 53 is taken as an example. In the single slope AD converter, a reference voltage V _ref having a so-called ramp (RAMP) waveform (gradient waveform) in which the voltage value changes stepwise as time passes is used. Reference voltage V _ref of the ramp waveform is generated by the reference voltage generator 57. The reference voltage generation unit 57 can be configured using, for example, a DAC (digital-analog conversion) circuit.

The AD converter 53 includes, for example, a comparator 531 and a counter 532. In the AD converter 53 according to this example, an up / down counter (denoted as “U / DCNT” in the drawing) is used as the counter 532. The comparator 531 uses the pixel signal read from each pixel 20 of the pixel array unit 13 as a comparison input, uses the reference voltage _Vref of the ramp wave supplied from the reference voltage generation unit 57 as a reference input, and compares the two. The comparator 531, for example, the reference voltage V _ref is output when larger than the pixel signal is a first state (e.g., high level) and the output reference voltage V _ref when: the pixel signal and the second (For example, low level). As a result, the output signal of the comparator 531 becomes a pulse signal having a pulse width corresponding to the level of the pixel signal.

The up / down counter 532 is supplied with the clock CK at the same timing as the supply start timing of the reference voltage V _{ref to} the comparator 531. Then, the up / down counter 532 performs a down (DOWN) count or an up (UP) count in synchronization with the clock CK, so that the period of the pulse width of the output pulse of the comparator 531, that is, the start of the comparison operation. The comparison period from the end of the comparison operation to the end of the comparison operation is measured. The count result (count value) of the up / down counter 532 becomes a digital value obtained by digitizing an analog pixel signal and is stored in the memory 54. Then, under scanning by the horizontal scanning unit 16 (see FIG. 2), a digital value obtained by AD converting an analog pixel signal from the memory 54 is appropriately read out.

In a solid-state imaging device (CMOS image sensor) in which the pixels 20 are arranged in a two-dimensional matrix, generally, correlated double sampling (CDS) is performed in order to remove noise during the reset operation of the pixels 20. ) To remove noise. For example, the reset level V _rst and the signal level V _sig are read from the pixel 20 in this order. The reset level V _rst corresponds to the potential of the floating diffusion FD when the floating diffusion FD of the pixel 20 is reset. The signal level V _sig is equivalent to the potential of the floating diffusion FD when the transfer charge stored in the photodiode 21 to the floating diffusion FD.

In the reading method for reading the reset level V _rst above, since the random noise generated when the reset is held in the floating diffusion FD, and the signal level V _sig read added signal charges, reset The same amount of noise as level V _rst is retained. For this reason, it is possible to obtain a signal from which these noises are removed by performing a correlated double sampling operation in which the reset level V _rst is subtracted from the signal level V _sig .

In the single slope AD converter 53 having the above configuration, a correlated double sampling process is executed during AD conversion. Specifically, in the AD converter 53, during the measurement operation in the comparison period from the start of the comparison operation in the comparator 531 to the end of the comparison operation, the up / down counter 532 is, for example, the reset level V _rst Down-counting, and up-counting is performed on the signal level V _sig . By this down count / up count operation, the difference between the signal level V _sig and the reset level V _rst can be obtained. As a result, noise removal processing by correlated double sampling is performed during AD conversion by the AD converter 53.

(Operation example)
Here, an operation example of the solid-state imaging device 10 according to the first embodiment will be described with reference to a timing waveform diagram of FIG. The timing waveform diagram of FIG. 5 shows the timing relationship of the transfer signal TRX, the reset signal RST, and the selection signal SEL that drive the unit pixel 20. The timing waveform diagram of FIG. 5 further shows changes in the potential of the signal line 32, the current flowing through the inductor 42 (coil current), the induced electromotive force generated in the inductor 42, and the output voltage of the signal detector 52. ing.

First, at time t ₁ , the reset signal RST transitions from a high level to a low level, so that the reset transistor 23 is turned off. As a result, the reset of the floating diffusion FD, that is, the gate electrode of the amplification transistor 24 is released, and the unit pixel 20 enters a non-reset state. At this time, the gate electrode of the amplifying transistor 24 is fixed to a potential corresponding to darkness (dark).

At time t ₁ , the selection signal SEL already transitions from the low level to the high level at this time, and the selection transistor 25 is in the conductive state, so that the dark output of the unit pixel 20 appears on the signal line 32. . The value of the current flowing through the inductor 42 is determined by the voltage of the signal line 32. Then, the peak value of the voltage change amount of the signal line 32 is clamped by the signal detection unit 52 on the second semiconductor chip 12 side through the inductor 42.

Subsequently, at time t _2, the transfer signal TRX is makes a transition from a low level to a high level, the transfer transistor 22 becomes conductive. Thereby, the photoelectric charge accumulated in the photodiode 21 is transferred to the floating diffusion FD. At this time, the voltage appearing on the signal line 32 and the current flowing through the inductor 42 (coil current) differ depending on the amount of incident light, for example, in the dark (dark), intermediate light amount, and high light amount. Then, through the induced electromotive force generated in the inductor 42, the output voltage of the signal detection unit 52 changes as shown in FIG.

As described above, in the AD converter 53, the correlated double sampling operation is realized by taking the difference between the reset level V _rst obtained after time t ₁ and the signal level V _sig obtained after time t _2. Can do. As a result, since noise during the reset operation of the unit pixel 20 can be removed, a good captured image can be obtained.

(Example of inductor layout)
Here, the layout of the inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side in the solid-state imaging device 10 according to the first embodiment will be described. An example of the layout of the inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side is shown in FIG.

In the solid-state imaging device 10 according to the first embodiment, the unit pixel 20 may be either a back-side illuminated pixel or a front-side illuminated pixel. However, it is preferable to use a back-illuminated pixel as the unit pixel 20 for the following reason.

In the first semiconductor chip 11, the unit pixel 20 is composed of a back-illuminated pixel, and the inductor 42 is formed on the front surface side of the substrate, that is, on the substrate surface opposite to the light-receiving side substrate surface of the back-illuminated pixel. It will be. Thereby, the light incident on the photoelectric conversion element (photodiode 21) is not blocked by the inductor 42.

The inductor 42 is preferably formed along the pixel column of the pixel array unit 13 as shown in FIG. Further, the inductor 42 is appropriately formed in one or more layers in a rectangular (rectangular) spiral shape using a material such as aluminum, copper, or tungsten on the surface side of the substrate. Here, the rectangular shape is exemplified as the shape of the inductor 42, but the shape is not limited to this, and the shape is not limited as long as an electromotive force can be generated.

The inductance L of the inductor 42 increases according to the number of turns (the number of windings) and the area of the inductor 42 and is expressed as an induced electromotive force V as in the above-described equation (1). Therefore, in order to increase the signal transmission efficiency between the first semiconductor chip 11 and the second semiconductor chip 12, the number of turns and the area should be increased with as thin a wiring as possible. Further, by being close to the transmission destination inductor 51, transmission efficiency can be further improved without leakage. In this respect, the solid-state imaging device 10 in which the unit pixel 20 is a back-illuminated pixel is effective because the inductor 42 can be formed using the entire pixel area of one pixel column of the pixel array unit 13. The inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side are close to each other through an insulating film (not shown) having a thickness that does not cause dielectric breakdown.

In the second semiconductor chip 12, when the first semiconductor chip 11 and the second semiconductor chip 12 are stacked with respect to the inductor 42 that transmits a signal from the first semiconductor chip 11, the second semiconductor chip 12 is in a state of being close to the inductor 42. Inductor 51 is formed. Similarly to the inductor 42, the inductor 51 is appropriately formed in one or more layers in a rectangular spiral shape using a material such as aluminum, copper, or tungsten. The inductor 51 receives a signal transmitted from the inductor 42.

This layout example illustrates a configuration in which the inductor 51 and the signal detection unit 52 are sequentially arranged in parallel, but is not limited to this configuration example. If the inductor 51 and the wiring layer constituting the signal detection unit 52 can be formed differently, the inductor 51 and the signal detection unit 52 are arranged so as to overlap in the direction perpendicular to the substrate surface of the second semiconductor chip 12. It is also possible to adopt a configuration.

(Other examples of inductor layout)
FIG. 7 shows another example of the layout of the inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side.

In the pixel array unit 13, a plurality of signal lines 32 may be provided for one pixel column. In FIG. 7, each pixel 20 of the pixel array unit 13 is divided into, for example, two vertically in the vertical direction (column direction), and the signal lines 32 corresponding to the upper and lower pixel lines with respect to one pixel column corresponding to this. An example in which two wires are arranged for a pixel is shown. Here, the upper pixel wiring is referred to as a signal line 32a, and the lower pixel wiring is referred to as a signal line 32b. That is, in the example of FIG. 7, two signal lines 32a and 32b divided vertically are arranged for one pixel column. However, the number of signal lines 32 for each pixel column is not limited to two, and may be three or more.

In this layout example, as shown in FIG. 7, in the first semiconductor chip 11, a plurality of inductors 42 are formed for one pixel column according to the number of signal lines 32. Specifically, the inductor 42a is formed for the upper pixel, and the voltage-current converter 41a is formed correspondingly. Similarly, an inductor 42b is formed for the lower pixel, and a voltage / current converter 41b is formed correspondingly.

Also in the second semiconductor chip 12, a plurality of inductors 51 are formed for one pixel column corresponding to the inductor 42 on the first semiconductor chip 11 side. Specifically, an inductor 51a is formed for the upper pixel, and a signal detection unit 52a and an AD converter 53a are formed correspondingly. Similarly, an inductor 51a is formed for the lower pixel, and a signal detector 52b and an AD converter 53b are formed correspondingly.

As described above, in the solid-state imaging device 10 according to the first embodiment, the first semiconductor chip 11 and the second semiconductor chip 12 are non-contacted by magnetic coupling in the region of the pixel array unit 13. Since signal transmission is performed, signal transmission with high transmission efficiency can be performed. Specifically, the layout occupancy of the elements (inductor 42 and inductor 51) constituting the signal transmission unit by magnetic coupling can be sufficiently secured as compared with the case where the layout is formed in a narrow region around the pixel array unit 13. Efficient signal transmission can be performed.

In particular, by using a back-illuminated pixel as the unit pixel 20, the inductor 42 can be formed on the substrate surface opposite to the light-receiving side substrate surface. Therefore, the degree of freedom in the layout of the inductor 42 is increased, and the layout of the inductor 42 is increased. The occupation ratio can be secured more sufficiently, and the laminated inductors 42 and 51 can be arranged close to each other. At this time, light incident on the photoelectric conversion element (photodiode 21) is not blocked by the inductor 42.

Also, since the signal transmission method is a magnetic coupling method, the problem of conductor connection by bumps can be solved. In other words, unlike the case of connecting with bumps and the like, the metal surface that becomes the electrode is not exposed, so there is no problem that the solid-state image sensor and the component of the signal processing unit are destroyed by electrostatic breakdown, and the yield is improved. Can be made. Furthermore, since it is not necessary to form a protective element for countermeasures against electrostatic breakdown, it is possible to reduce the size of the solid-state imaging device and speed up signal transmission.

Further, in the solid-state imaging device 10 according to the first embodiment, the transmission target signal transmitted from the first semiconductor chip 11 side to the second semiconductor chip 12 side is an analog signal (analog pixel signal). In this case, since the transient state before the potential of the signal line 32 is settled is detected and transmitted to the second semiconductor chip 12 side, the potential of the signal line 32 after the stabilization is AD-converted, and then the pixel Transmission can be performed earlier than the method of reading and transmitting to the peripheral region of the array unit 13 (see, for example, Non-Patent Document 1). As a result, the reading speed of the analog pixel signal can be increased. Incidentally, when the analog pixel signal is AD-converted and then read out to the peripheral area of the pixel array unit 13, the pixel signal after AD conversion is transmitted, so that it takes time to transmit to the second semiconductor chip 12 side. It will take.

Further, in the solid-state imaging device 10 according to the first embodiment, since the inductor 42 is formed along the pixel column of the pixel array unit 13 (see FIG. 6), the inductor 42 is connected to the signal line (column signal line). / Vertical signal line) 32 is laid out in parallel. As a result, the capacitive coupling due to the parasitic capacitance between the signal line 32 and the inductor 42 allows the response of the electromotive force generated in the inductor 42 to follow the change in the potential of the signal line 32. Higher speed can be achieved.

Second Embodiment
Similarly to the solid-state image sensor according to the first embodiment, the solid-state image sensor according to the second embodiment is also based on a stacked solid-state image sensor, and the first semiconductor chip 11 and the second semiconductor chip 11 Electric signals are transmitted to and from the semiconductor chip 12 in a non-contact manner. However, in the solid-state imaging device according to the first embodiment, the signal to be transmitted is an analog signal, whereas in the solid-state imaging device according to the second embodiment, the signal to be transmitted is a digital signal.

FIG. 8 is a block diagram illustrating an overall configuration example of a solid-state imaging device (stacked solid-state imaging device) according to the second embodiment. The unit pixel on the first semiconductor chip side and the signal detection unit on the second semiconductor chip side An example of the circuit configuration is shown in the circuit diagram of FIG. FIG. 8 mainly illustrates only functional units related to the technology of the present disclosure.

(First semiconductor chip)
In the first semiconductor chip 11, the unit pixels 20 arranged in a two-dimensional matrix are configured to have an AD conversion function for converting an analog signal corresponding to incident light into a digital signal. Specifically, the unit pixel 20 includes a comparator 26 and a control transistor 27 in addition to the photodiode 21, the transfer transistor 22, and the reset transistor 23. The comparator 26 corresponds to the comparator 531 in the AD converter (ADC) 53 shown in FIG. 4B.

The comparator 26 uses the potential of the floating diffusion FD as a comparison input and the reference voltage V _ref of the ramp wave as a reference input, and compares the two. The reference voltage V _ref is generated by the reference voltage generator 57 (see FIG. 4B). The comparator 26 compares the potential (signal level) of the floating diffusion FD when the signal charge is transferred from the photodiode 21 by the transfer transistor 22 with the reference voltage V _ref of the ramp wave, thereby comparing the signal of the unit pixel 20. Digitize. The comparison output of the comparator 26 becomes the gate input of the control transistor 27.

In the solid-state imaging device 10 according to the second embodiment, one inductor 42 on the first semiconductor chip 11 side is provided for one unit pixel 20 of the pixel array unit 13. However, the present invention is not limited to this. For example, when a configuration in which each pixel 20 of the pixel array unit 13 is divided using a plurality of adjacent unit pixels 20 as a unit, a pixel unit including a plurality of unit pixels 20 is used. A configuration in which one inductor 42 is provided is also possible.

The inductor 42 is connected between the drain electrode of each control transistor 27 of the unit pixel 20 and the power source on the high potential (for example, power supply potential V _dd ) side. The source electrode of the control transistor 27 is connected to a low potential side power source (for example, ground) via the resistance element 28. As a result, the control transistor 27 performs on / off control of the current flowing through the inductor 42 in accordance with the comparison output of the comparator 26.

Specifically, the comparator 26 generates a high-level output at the timing when the potential of the floating diffusion FD matches the reference voltage _{Vref of the} ramp wave. In response to this, the control transistor 27 becomes conductive, whereby a current flows from the power supply potential V _dd to the ground through the inductor 42, the control transistor 27, and the resistance element 28. At this time, an electromotive force corresponding to the flowing current is generated in the inductor 42 and is transmitted to the inductor 51 on the second semiconductor chip 12 side by a mutual induction effect.

(Second semiconductor chip)
In the second semiconductor chip 12, the signal detection unit 52 includes a resistance element 523, a capacitance element 524, a counter 525, and a memory 526. The resistive element 523 and the capacitive element 524 are connected to both ends of the inductor 51, and a signal is transmitted from the inductor 42 on the first semiconductor chip 11 side due to mutual induction, thereby generating an electromotive force generated in the inductor 51. Convert to square wave. The pulse width of this rectangular wave corresponds to the level of the pixel signal of the unit pixel 20.

The counter 525 corresponds to the counter 532 in the AD converter 53 shown in FIG. 4B, and includes, for example, an up / down counter. The counter 525 is supplied with the clock CK at the same timing as the supply start timing of the reference signal V _ref to the comparator 26 of the unit pixel 20. The counter 525 performs down-counting or up-counting in synchronization with the clock CK, so that the pulse width period of the rectangular wave converted by the resistor 523 and the capacitor 524, that is, the comparison operation of the comparator 26 is performed. The comparison period from the start to the end of the comparison operation is measured.

The measurement result of the counter 525 is stored in the memory 526. The memory 526 corresponds to the memory 54 in the signal processing unit 15 illustrated in FIG. The signal detection unit 52 is sequentially selected by the vertical scanning by the vertical scanning unit 14 and the horizontal scanning by the horizontal scanning unit 16, and a digital signal is transmitted from the memory 526 of the selected signal detection unit 52 through the column selection switch 55. Read to output line 56. The read digital pixel signal is subjected to final signal processing as necessary. Thereafter, the digital image data is output to the second semiconductor chip 12.

Here, an operation example of the solid-state imaging device 10 according to the second embodiment will be described with reference to a timing waveform diagram of FIG. The timing waveform diagram of FIG. 10 shows the timing relationship between the reset signal RST and the transfer signal TRX that drive the unit pixel 20. The timing waveform diagram of FIG. 10 further shows changes in the comparison output of the comparator 26, the current flowing through the inductor 42 (coil current), the induced electromotive force generated in the inductor 42, and the output voltage of the signal detection unit 52. ing.

First, at time t ₁ , the reset signal RST transitions from a high level to a low level, so that the reset transistor 23 is turned off. As a result, the reset of the floating diffusion FD, that is, the input end of the comparator 26, is released, and the unit pixel 20 enters a non-reset state. At this time, the input terminal of the comparator 26 is fixed at a potential corresponding to darkness.

Thereafter, the comparator 26 compares the potential of the floating diffusion FD with the reference voltage V _ref of the ramp wave. Then, a determination potential of logic “0” / “1” is output from the comparator 26 according to the comparison result. When the determination potential of the comparator 26 is logic “1” (high level), the control transistor 27 becomes conductive, and a current (coil current) flows through the inductor 42. Then, an induced electromotive force is generated in the inductor 42 at the change point of the coil current, and is transmitted to the inductor 51 on the second semiconductor chip 12 side by mutual induction. By this signal transmission, the signal detector 52 generates a rectangular wave. Then, in the signal detection unit 52, the counter 525 counts the pulse width of the rectangular wave, and the measurement result is stored in the memory 526.

Subsequently, at time t _2, the transfer signal TRX is makes a transition from a low level to a high level, the transfer transistor 22 becomes conductive. Thereby, the photoelectric charge accumulated in the photodiode 21 is transferred to the floating diffusion FD. The comparator 26 compares the potential of the floating diffusion FD and the reference voltage V _ref of the ramp wave, and outputs a determination potential of logic “0” / “1” from the comparator 26 according to the comparison result. Is done. At this time, an induced electromotive force is generated in the inductor 42 at a timing according to the amount of incident light, and is transmitted to the inductor 51 on the second semiconductor chip 12 side by mutual induction. In addition, the signal detection unit 52 generates a rectangular wave and counts the pulse width of the rectangular wave, and stores the measurement result in the memory 526.

Also in the solid-state imaging device 10 according to the second embodiment, by using an up / down counter as the counter 525, a correlated double sampling operation can be realized during AD conversion. Thereby, noise during the reset operation of the unit pixel 20 can be removed, so that a good captured image can be obtained.

(Inductor layout)
Here, the layout of the inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side in the solid-state imaging device 10 according to the second embodiment will be described. An example of the layout of the inductor 42 on the first semiconductor chip 11 side and the inductor 51 on the second semiconductor chip 12 side is shown in FIG.

In the solid-state imaging device 10 according to the second embodiment, the unit pixel 20 may be either a back-illuminated pixel or a front-illuminated pixel. However, for the reason described in the first embodiment, it is preferable to use a back-illuminated pixel as the unit pixel 20.

In the first semiconductor chip 11, one inductor 42 is preferably formed for each unit pixel 20, as shown in FIG. Further, the inductor 42 is appropriately formed in one or more layers in a rectangular (rectangular) spiral shape using a material such as aluminum, copper, or tungsten on the surface side of the substrate. Here, the rectangular shape is exemplified as the shape of the inductor 42, but the shape is not limited to this, and the shape is not limited as long as an electromotive force can be generated.

In the second semiconductor chip 12, when the first semiconductor chip 11 and the second semiconductor chip 12 are stacked with respect to the inductor 42 that transmits a signal from the first semiconductor chip 11, the second semiconductor chip 12 is in a state of being close to the inductor 42. In addition, one inductor 51 is formed for each signal detector 52. Similarly to the inductor 42, the inductor 51 is appropriately formed in one or more layers in a rectangular spiral shape using a material such as aluminum, copper, or tungsten. The inductor 51 receives a signal transmitted from the inductor 42.

As described above, even in the solid-state imaging device 10 according to the second embodiment, the first semiconductor chip 11 and the second semiconductor chip 12 are contacted by magnetic coupling in the region of the pixel array unit 13. Since signal transmission is performed, signal transmission with high transmission efficiency can be performed. In the solid-state imaging device 10 according to the first embodiment, the transmission target signal is an analog signal, whereas in the solid-state imaging device 10 according to the present embodiment, the transmission target signal is a digital signal. In this way, by adopting a configuration for transmitting a digital pixel signal that is AD-converted for each unit pixel 20, the narrow pitch of bumps that require physical connection is eliminated, and it is possible to stack fine pixels. .

<Modification>
Although the present disclosure has been described based on the preferred embodiments, the present disclosure is not limited to these embodiments. The configuration and structure of the solid-state imaging device described in the above embodiments and the configuration of the driving method of the solid-state imaging device are examples, and can be changed as appropriate.

For example, in each of the above-described embodiments, the transmission method based on magnetic coupling using magnetism (magnetic field) is exemplified as the transmission method based on the non-contact signal between the first semiconductor chip 11 and the second semiconductor chip 12. It is not limited to. As another non-contact transmission method, for example, a transmission method using electrostatic coupling using an electric field can be exemplified. FIG. 12 shows a principle diagram of a transmission method using electrostatic coupling. In the transmission method using electrostatic coupling, two plate electrodes 61 and 62 are used. When a signal voltage is applied to one plate electrode 61, a signal voltage is induced on the other plate electrode 62 in proportion to the capacitance between the two plate electrodes 61 and 62. Signal transmission is performed by the electric field between the two plate electrodes 61 and 62.

Therefore, when using a transmission method based on electrostatic coupling as a non-contact transmission method, one flat plate electrode 61 is formed on the first semiconductor chip 11 and the other flat plate electrode 62 is formed on the second semiconductor chip 12. Thus, non-contact transmission of signals can be realized between the first semiconductor chip 11 and the second semiconductor chip 12.

<Electronic device of the present disclosure>
The solid-state imaging device according to the first and second embodiments described above uses an imaging device such as a digital still camera and a video camera, a portable terminal device having an imaging function such as a mobile phone, and a solid-state imaging device for an image reading unit. It can be used as an imaging unit (image capturing unit) in electronic devices such as copying machines. In some cases, the above-described module form mounted on an electronic device, that is, a camera module is used as an imaging device.

[Imaging device]
FIG. 13 is a block diagram illustrating a configuration of an imaging apparatus that is an example of the electronic apparatus of the present disclosure. As shown in FIG. 13, an imaging apparatus 100 according to this example includes an optical system 101 including a lens group, an imaging unit 102, a DSP circuit 103 that is a camera signal processing unit, a frame memory 104, a display device 105, and a recording device 106. , An operation system 107, a power supply system 108, and the like. The DSP circuit 103, the frame memory 104, the display device 105, the recording device 106, the operation system 107, and the power supply system 108 are connected to each other via a bus line 109.

The optical system 101 takes in incident light (image light) from a subject and forms an image on the imaging surface of the imaging unit 102. The imaging unit 102 converts the amount of incident light imaged on the imaging surface by the optical system 101 into an electrical signal for each pixel and outputs the electrical signal as a pixel signal. The DSP circuit 103 performs general camera signal processing, such as white balance processing, demosaic processing, and gamma correction processing.

The frame memory 104 is used for storing data as appropriate during the signal processing in the DSP circuit 103. The display device 105 includes a panel type display device such as a liquid crystal display device or an organic EL (electroluminescence) display device, and displays a moving image or a still image captured by the imaging unit 102. The recording device 106 records the moving image or still image captured by the imaging unit 102 on a recording medium such as a portable semiconductor memory, an optical disk, or an HDD (Hard Disk Disk Drive).

The operation system 107 issues operation commands for various functions of the imaging apparatus 100 under the operation of the user. The power supply system 108 appropriately supplies various power supplies serving as operation power for the DSP circuit 103, the frame memory 104, the display device 105, the recording device 106, and the operation system 107 to these supply targets.

In the imaging apparatus 100 having the above-described configuration, the solid-state imaging device according to the first and second embodiments described above can be used as the imaging unit 102.

In addition, this indication can also take the following structures.
[1] a first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
A second semiconductor chip having a signal processing unit that is stacked on the first semiconductor chip and that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
In the region of the pixel array unit, a signal transmission unit that transmits electrical signals in a non-contact manner between the first semiconductor chip and the second semiconductor chip;
A solid-state imaging device.
[2] The signal transmission unit transmits an electric signal between the first semiconductor chip and the second semiconductor chip by magnetic coupling of the inductor.
The solid-state imaging device according to [1] above.
[3] The unit pixel is a back-illuminated pixel.
The solid-state imaging device according to the above [1] or [2].
[4] The electrical signal transmitted by the signal transmission unit is an analog signal.
The solid-state imaging device according to any one of [1] to [3] above.
[5] The electrical signal transmitted by the signal transmission unit is a digital signal.
The solid-state imaging device according to any one of [1] to [3] above.
[6] The unit pixel has a function of converting an analog signal corresponding to incident light into a digital signal.
The solid-state imaging device according to [5] above.
[7] One or more inductors in the signal transmission unit are provided for one pixel column in the pixel array unit.
The solid-state imaging device according to any one of [2] to [6] above.
[8] The inductor in the signal transmission unit is formed along each pixel column of the pixel array unit.
The solid-state imaging device according to [7] above.
[9] One inductor in the signal transmission unit is provided for one unit pixel of the pixel array unit, or one for a pixel unit including a plurality of unit pixels.
The solid-state imaging device according to any one of [2] to [5] above.
[10] The inductor in the signal transmission unit is formed on the substrate surface opposite to the light-receiving side substrate surface of the back-illuminated pixel of the first semiconductor chip.
The solid-state imaging device according to any one of [3] to [9] above.
[11] a first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
A second semiconductor chip having a signal processing unit that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
When driving a solid-state imaging device that is laminated,
In the region of the pixel array portion, electrical signals are transmitted in a non-contact manner between the first semiconductor chip and the second semiconductor chip.
A method for driving a solid-state imaging device.
[12] An electric signal is transmitted between the first semiconductor chip and the second semiconductor chip by magnetic coupling of the inductor.
The method for driving a solid-state imaging device according to [11] above.
[13] The unit pixel is a back-illuminated pixel.
The method for driving a solid-state imaging device according to the above [11] or [12].
[14] The electrical signal transmitted between the first semiconductor chip and the second semiconductor chip is an analog signal.
The method for driving a solid-state imaging device according to any one of [11] to [13].
[15] The electrical signal transmitted between the first semiconductor chip and the second semiconductor chip is a digital signal.
The method for driving a solid-state imaging device according to any one of [11] to [13].
[16] a first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
A second semiconductor chip having a signal processing unit that is stacked on the first semiconductor chip and that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
In the region of the pixel array unit, a signal transmission unit that transmits electrical signals in a non-contact manner between the first semiconductor chip and the second semiconductor chip;
An electronic apparatus having a solid-state imaging device.
[17] The signal transmission unit transmits an electric signal between the first semiconductor chip and the second semiconductor chip by magnetic coupling of the inductor.
The electronic device according to [16] above.
[18] The unit pixel is a back-illuminated pixel.
The electronic device according to the above [16] or [17].
[19] The electrical signal transmitted by the signal transmission unit is an analog signal.
The electronic device according to any one of [16] to [18].
[20] The electrical signal transmitted by the signal transmission unit is a digital signal.
The electronic device according to any one of [16] to [18].

DESCRIPTION OF SYMBOLS 10 ... Stack type solid-state image sensor, 11 ... 1st semiconductor chip, 12 ... 2nd semiconductor chip, 13 ... Pixel array part (pixel part), 14, 17 ... Vertical scanning part, DESCRIPTION OF SYMBOLS 15 ... Signal processing part, 16 ... Horizontal scanning part, 20 ... Unit pixel, 21 ... Photodiode, 22 ... Transfer transistor, 23 ... Reset transistor, 24 ... Amplification transistor 25... Selection transistor, 26... Comparator, 27... Control transistor, 31 (31 ₁ to 31 _m )... Pixel drive line, 32 (32 ₁ to 32 _n ). 33 ... constant current source, 41 ... voltage-current converter, 42, 51 ... inductor (coil), 52 ... signal detector, 53 ... analog-digital converter (AD converter) 54 ... Memory 55 ... Column select switch, 56 ... signal output line, 57 ... reference voltage generating unit

Claims (20)

1. A first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
   A second semiconductor chip having a signal processing unit that is stacked on the first semiconductor chip and that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
   In the region of the pixel array unit, a signal transmission unit that transmits electrical signals in a non-contact manner between the first semiconductor chip and the second semiconductor chip;
   A solid-state imaging device.
2. The signal transmission unit transmits an electrical signal by magnetic coupling of the inductor between the first semiconductor chip and the second semiconductor chip.
   The solid-state imaging device according to claim 1.
3. The unit pixel is a back-illuminated pixel.
   The solid-state imaging device according to claim 1.
4. The electrical signal transmitted by the signal transmission unit is an analog signal.
   The solid-state imaging device according to claim 1.
5. The electrical signal transmitted by the signal transmission unit is a digital signal.
   The solid-state imaging device according to claim 1.
6. The unit pixel has a function of converting an analog signal corresponding to incident light into a digital signal.
   The solid-state imaging device according to claim 5.
7. One or more inductors in the signal transmission unit are provided for one pixel column of the pixel array unit,
   The solid-state imaging device according to claim 2.
8. The inductor in the signal transmission unit is formed along each pixel column of the pixel array unit,
   The solid-state imaging device according to claim 7.
9. One inductor for the signal transmission unit is provided for one unit pixel of the pixel array unit, or one for a pixel unit composed of a plurality of unit pixels.
   The solid-state imaging device according to claim 2.
10. The inductor in the signal transmission unit is formed on the substrate surface opposite to the light receiving side substrate surface of the back-illuminated pixel of the first semiconductor chip.
    The solid-state imaging device according to claim 3.
11. A first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
    A second semiconductor chip having a signal processing unit that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
    When driving a solid-state imaging device that is laminated,
    In the region of the pixel array portion, electrical signals are transmitted in a non-contact manner between the first semiconductor chip and the second semiconductor chip.
    A method for driving a solid-state imaging device.
12. An electrical signal is transmitted between the first semiconductor chip and the second semiconductor chip by magnetic coupling of the inductor.
    The method for driving a solid-state imaging device according to claim 11.
13. The unit pixel is a back-illuminated pixel.
    The method for driving a solid-state imaging device according to claim 11.
14. The electrical signal transmitted between the first semiconductor chip and the second semiconductor chip is an analog signal.
    The method for driving a solid-state imaging device according to claim 11.
15. The electrical signal transmitted between the first semiconductor chip and the second semiconductor chip is a digital signal.
    The method for driving a solid-state imaging device according to claim 11.
16. A first semiconductor chip having a pixel array unit in which unit pixels for generating an electrical signal corresponding to incident light are arranged;
    A second semiconductor chip having a signal processing unit that is stacked on the first semiconductor chip and that performs predetermined signal processing on an electrical signal generated by each unit pixel of the pixel array unit;
    In the region of the pixel array unit, a signal transmission unit that transmits electrical signals in a non-contact manner between the first semiconductor chip and the second semiconductor chip;
    An electronic apparatus having a solid-state imaging device.
17. The signal transmission unit transmits an electrical signal by magnetic coupling of the inductor between the first semiconductor chip and the second semiconductor chip.
    The electronic device according to claim 16.
18. The unit pixel is a back-illuminated pixel.
    The electronic device according to claim 16.
19. The electrical signal transmitted by the signal transmission unit is an analog signal.
    The electronic device according to claim 16.
20. The electrical signal transmitted by the signal transmission unit is a digital signal.
    The electronic device according to claim 16.

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