JP5008905B2 - Solid-state imaging device - Google Patents

Description

  The present invention relates to a solid-state imaging device such as a complementary metal oxide semiconductor (CMOS) image sensor and a charge coupled device (CCD) image sensor.

  A general solid-state imaging device converts light (external light) incident on a photodiode included in a pixel into an electric charge. Therefore, the optical signal incident on the light receiving surface (photoelectric conversion region) of the photodiode is converted into an electrical signal in units of pixels. Then, as the area ratio (aperture ratio) of the light receiving surface to the pixel area is higher, more optical signals are acquired, and the sensitivity of the solid-state imaging device is improved.

  However, other elements (for example, transistors) other than the photoelectric conversion region are included in the pixel area. Therefore, there is a limit to improving the aperture ratio. Therefore, various solid-state imaging devices having a microlens (on-chip lens) for condensing external light on the photoelectric conversion region have been developed. This is because such a microlens condenses external light (that is, increases the amount of light) and leads it to the photoelectric conversion region, thereby improving the sensitivity of the solid-state imaging device (in addition, such an increase in the amount of light). This may be expressed as an improvement in the apparent aperture ratio).

  Recently, however, the pixel size has been reduced (that is, the pixel pitch has been reduced) due to the demand for higher pixels in the solid-state imaging device. For this reason, the surface size (outer diameter, etc.) of the microlens for each pixel provided on the pixel surface is also reduced, and the amount of light guided to the photoelectric conversion region is hardly improved.

Therefore, in order to effectively increase the amount of light, various solid-state imaging devices 139 having an in-layer lens is provided between the microlens ms and the photodiode dd have been developed as shown in FIG. Reference 1). This is because such an intra-layer lens is collects the transmitted light from the microlens ms and guides it to the photoelectric conversion region.
Japanese Patent Laid-Open No. 11-40787

  However, in the solid-state imaging device 139 of Patent Document 1, the pitch of the pixels (that is, the pitch of the microlenses MS) is equal, and the pitch of the photodiodes dd is also equal. Further, the light receiving surface of the photodiode dd Above the side, the microlens ms and the in-layer lens is are arranged so as to overlap each other. With such a solid-state imaging device 139, the transmitted light of the microlens ms can be guided to the photodiode dd by the in-layer lens is. However, in the case of the solid-state imaging device 139 as shown in FIG. The problem will be described below with reference to FIG. 8 and FIGS. 9 and 10 (note that hatching in the cross-sectional view may be omitted for easy understanding).

  The solid-state imaging device 139 shown in FIG. 8 has in-plane arrangement of pixels in 2 rows and 2 columns as a set (pixel set), and the pixel pitch (that is, the pitch Pa of the microlens ms) and the pitch of the in-layer lens is. Pb is equally spaced. In this solid-state imaging device 139, the in-plane centers (black circles) of the microlens ms and the in-layer lens is are matched (overlapped), and the outer diameter is also the same, so that Pa = Pb.

  However, the photodiode dd is disposed so as to approach the in-plane center of the pixel group. Therefore, the interval Pd between the photodiodes dd in the pixel group is different from the interval Pe between the photodiodes dd in adjacent pixel groups (note that the white circle is the in-plane center of the photoelectric conversion region, and Pd <Pe, Pd + Pe = Pa × 2 = Pb × 2).

  Therefore, in the solid-state imaging device 139, although the pixel pitches are equally spaced, the photodiodes dd have unequal pitches. The pixel includes a color filter (not shown). The red (RED) pixel is “R”, the green (GREEN) pixel is “G”, and the blue (BLUE) pixel is “B”. It is attached.

  Further, as shown in FIG. 9, one direction in the plane of the light receiving surface ir composed of a plurality of pixels is set in the x direction, and one direction in the plane perpendicular to the x direction is set in the y direction, and in the x direction and the y direction. If the exit pupil EP is positioned above the light receiving surface ir when the correct direction is the z direction, the incident light is inclined with respect to the exit pupil EP in the x direction of the light receiving surface. That is, on one light receiving surface [AREA (L)] in the x direction with the exit pupil EP as a boundary, incident light has an incident angle (+ θx) of θx, and the other light receiving surface [AREA (R ]], However, the incident light has an incident angle (−θx) of θx.

  Then, the incident angle as shown in FIG. 9 is generated even in the incident light in the solid-state imaging device 139 of FIG. This is illustrated in FIGS. 10A and 10B. The solid-state imaging device 139 of FIGS. 10A and 10B corresponds to one surface composed of the x direction and the z direction in FIG. 9, and FIG. 10A is the light receiving surface [AREA (L)] in FIG. Corresponds to the light receiving surface [AREA (R)] in FIG. 10A and 10B, since blue and green color filters or green and red color filters are arranged in the y direction, “B / G, G / R” is selected according to the color of the color filter. "Is attached.

  As shown in FIGS. 10A and 10B, when the normal direction of the surface vertex of the microlens ms is used as the reference axis, the in-plane center of the light receiving surface of the photodiode dd is shifted from the reference axis. More specifically, in FIG. 10A, the photodiode dd corresponding to the B / G color filter is shifted so as to approach the condensing point of light having an incident angle (+ θx) transmitted through the microlens ms and the in-layer lens is, The photodiode dd corresponding to the G / R color filter is shifted away from the condensing point. Therefore, a large amount of light reaches the photodiode dd corresponding to the B / G color filter, but only a small amount of light reaches the photodiode dd corresponding to the G / R color filter. Therefore, one of all the pixel surfaces is bluish.

  On the other hand, in FIG. 10B, the photodiode dd corresponding to the G / R color filter is shifted so as to approach the condensing point of the light having the incident angle (−θx) transmitted through the microlens ms and the in-layer lens is. The photodiode dd corresponding to the B / G color filter is shifted away from the condensing point. Therefore, a large amount of light reaches the photodiode dd corresponding to the G / R color filter, but only a small amount of light reaches the photodiode dd corresponding to the B / G color filter. Therefore, the other pixel surface becomes reddish.

  Such a tinted phenomenon is called a color shading phenomenon, and this color shading phenomenon also occurs in one and the other in the y direction with the exit pupil EP as a boundary in FIG. Therefore, the solid-state imaging device 139 as shown in FIG. 8 cannot provide a high-quality color image. The reason is that the same amount (uniform amount) of light does not reach the photodiodes dd in all the pixels.

  The present invention has been made in view of the above situation. An object of the present invention is to provide a solid-state image pickup device having solid-state image pickup devices (solid-state image pickup devices in which the pitches of the photodiodes are unequally spaced) having photodiodes arranged in unequal intervals in an in-plane arrangement. The purpose is to reach the same amount of light.

  A solid-state imaging device according to the present invention includes pixels having photoelectric conversion units arranged in unequal intervals in an in-plane arrangement, condenses external light arranged in an in-plane arrangement at equal intervals, and transmits the micro lens. And an internal lens that collects the light to be collected. Such a solid-state imaging device guides the external light transmitted through the microlens to the photoelectric conversion unit by transmitting the external light through the internal lenses arranged at unequal intervals in the in-plane arrangement.

  In order to describe in detail here, a reference axis facing external light is set for each of the microlens, the internal lens, and the photoelectric conversion unit, the reference axis of the microlens is the first axis, and the reference axis of the internal lens is the second. The third axis is the axis and the reference axis of the photoelectric conversion unit. And, when the photoelectric conversion unit is arranged so as to shift the third axis with respect to the first axis, the internal lens is arranged so as to shift the second axis with respect to the first axis, It can be said that the present invention is a solid-state imaging device in which light transmitted through the internal lens is guided to a photoelectric conversion unit arranged in a shifted manner.

  However, it is desirable that the direction in which the second axis deviates from the first axis coincides with the direction in which the third axis deviates from the first axis. Further, it is desirable that the amount of deviation of the second axis with respect to the first axis is the same as the amount of deviation of the third axis with respect to the first axis.

  In addition, when each pixel has spectral characteristics, it is desirable that a plurality of types of pixels are gathered to form a pixel set in terms of spectral characteristics. In addition, it is desirable that all color information is acquired in at least some of the pixels in the pixel set.

  Further, it is desirable that the solid-state imaging device is provided with a signal amplifying unit that amplifies an electric signal generated by the photoelectric conversion unit. Note that it is desirable that one or more signal amplifying units are provided corresponding to one or a plurality of pixel sets.

  In addition, when the signal amplification unit is disposed in a gap space between the photoelectric conversion units, an element isolation unit that electrically insulates the photoelectric conversion units is provided in the gap space where the signal amplification unit does not exist. It is desirable.

  In particular, when the pixel group is composed of pixels having photoelectric conversion portions that are densely arranged by being shifted (for example, in the case of a pixel group having an in-plane arrangement of 2 rows and 2 columns), the element separation unit is included in the pixel group. It is desirable to be provided in the gap space. The material of the element isolation part is not particularly limited, but is preferably made of an impurity diffusion material.

  According to the solid-state imaging device of the present invention, the internal lenses arranged at unequal intervals in the in-plane arrangement are interposed between the microlens and the photoelectric conversion unit. With such an internal lens, external light once collected at equal intervals by the microlenses arranged at equal intervals in the in-plane arrangement is collected so as to match the photoelectric conversion units arranged at irregular intervals in the in-plane arrangement. Can shine. Therefore, all the photoelectric conversion units can receive a uniform light amount.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to the drawings. In addition, although member numbers etc. may be abbreviate | omitted for convenience for some drawings, in such a case, other drawings shall be referred to. In some cases, hatching is omitted for easy understanding.

  FIG. 1 is a cross-sectional view and a plan view mainly showing pixels of the solid-state imaging device 39. As shown in FIG. 1, the solid-state imaging device 39 includes a photodiode (photoelectric conversion unit) DD incorporated in a substrate 11 and an intralayer lens (internally positioned on an interlayer insulating film 12 stacked on the substrate 11. Lens) IS and a microlens MS located on the flattening film 13 laminated on the interlayer insulating film 12.

  It should be noted that the longest side in the pixel surface size (region divided by the broken line) and the diameter (outer diameter) of the microlens MS are substantially the same size, and the pixel pitch and the microlens MS pitch are the same. Interval (same pitch). In addition, the in-plane center of the pixel coincides with the in-plane center of the microlens MS (the in-plane center is indicated by a black circle).

  And this solid-state imaging device 39 makes the space | interval Ta of pixels (microlenses MS) equal intervals, and makes the pixel of 2 rows 2 columns into 1 set (pixel group) by in-plane arrangement | positioning. The pitch is also set at equal intervals (interval Ta × 2). In the solid-state imaging device 39, the photodiode DD and the in-layer lens IS are arranged so as to approach the in-plane center of the pixel group (note that the center of the light-receiving surface of the photodiode DD and the in-plane center of the in-layer lens IS). And match (indicated by white circles).

  However, the interval Tb between the in-layer lenses IS in the pixel set is different from the interval Tc between the in-layer lenses IS in the adjacent pixel sets (Tb <Tc). Further, the interval Td between the photodiodes DD in the pixel group is different from the interval Te between the photodiodes DD in the adjacent pixel groups (Td <Te).

  In the solid-state imaging device 39 shown in FIG. 1, the interval Tb and the interval Td coincide with each other, and the interval Tc and the interval Te coincide with each other (Tb = Td, Tc = Te). In the interval, the relationship of “Tb + Tc = Ta × 2, Td + Te = Ta × 2” is established.

  Therefore, in the solid-state imaging device 39, although the pitches in the in-plane arrangement of the pixels are equally spaced, the pitches in the in-plane arrangement of the photodiodes DD and the in-layer lenses IS are unequal (in-layer) In the case of the lens IS, there is a spacing Tb · Tc, and in the case of the photodiode DD, there is a spacing Td · Te).

For convenience, when a reference axis directed to external light is set for each of the microlens MS, the in-layer lens IS, and the photodiode DD, the reference axis of the microlens MS is the first axis A1, and the in-layer lens IS. Assuming that the reference axis is the second axis A2 and the reference axis of the photodiode DD is the third axis A3, the following relationship is established.
-Distance between first axes A1 of adjacent microlenses MS = distance Ta
The distance between the second axes A2 of the in-layer lenses IS within the pixel set = the distance Tb
The distance between the second axes A2 of the in-layer lenses IS between the pixel groups = the distance Tc
The interval between the third axes A3 of the photodiodes DD within the pixel group = the interval Td
The interval between the third axes A3 of the photodiodes DD between the pixel groups = the interval Te

  Then, in the solid-state imaging device 39, the photodiode DD is disposed so as to be shifted with respect to the first axis A1, and the second axis A2 is shifted with respect to the first axis A1. It can be said that the inner lens IS is displaced.

  In the color-compatible solid-state imaging device 39, the pixel includes a color filter (not shown) and the like. Therefore, “R” is applied to a pixel having a red (RED) color filter, “G” is applied to a pixel having a green (GREEN) color filter, and “B” is applied to a pixel having a blue (BLUE) color filter. It is attached. Then, it can be said that the solid-state imaging device 39 of FIG. 1 has a Bayer type color filter. In the cross-sectional view of FIG. 1, since the blue and green color filters or the green and red color filters are arranged in the direction from the front to the back of the sheet, “B” is selected according to the color of the color filter. / G, G / R "is attached.

  The solid-state imaging device 39 including a plurality of pixels having the photodiode DD as described above condenses external light on the microlens MS and condenses light transmitted through the microlens MS on the in-layer lens IS. The external light is guided to the photodiodes DD arranged at unequal intervals in the plane. FIGS. 2A to 2C show the optical path of the external light, that is, the optical path of the external light (dotted line) from the outside to the light receiving surface of the photodiode DD.

  2A to 2C are diagrams showing an example of the optical path of the external light, and FIG. 2A shows the optical path of the external light traveling in the same direction as the first axis A1. On the other hand, FIG. 2B shows an optical path of external light incident with an inclination (+ θ) with respect to the first axis A1, and FIG. 2C shows an optical path of external light incident with an inclination (−θ) in the opposite direction to FIG. ing.

  As shown in these drawings, when the photodiode DD is arranged so as to shift the third axis A3 with respect to the first axis A1, the inner layer is shifted so as to shift the second axis A2 with respect to the first axis A1. When the lens IS is displaced, light transmitted through the in-layer lens IS reaches the photodiode DD that is displaced.

  That is, the external light once condensed at equal intervals by the microlenses MS arranged at equal intervals Ta is unequal (interval Td · Te) by the intra-layer lenses IS arranged at unequal intervals (intervals Tb · Tc). ) To the photodiode DD.

  Therefore, external light can reach the center of the light receiving surface of the photodiode DD, and all the photodiodes DD receive a uniform amount of light. In other words, a situation in which a part of the pixels receives a large amount of light while a remaining part of the pixels can receive only a small amount of light in the entire pixel surface cannot occur.

  Then, due to a certain incident angle (for example, + θ) of external light, for example, a large amount of external light is incident on a pixel having a Bayer-type blue and green color filter, while the green and red color filters are included. A situation where only a small amount of external light is incident on the pixel cannot occur. Further, due to other incident angles (for example, -θ) of external light, a large amount of external light is incident on a pixel having, for example, a Bayer-type green and red color filter, while a blue and green color filter A situation in which only a small amount of external light is incident on a pixel having a pixel cannot occur. That is, the color shading phenomenon does not occur in the color-compatible solid-state imaging device 39.

  The solid-state imaging device 39 in FIG. 1 is an example in which the direction in which the second axis A2 is shifted from the first axis A1 and the direction in which the third axis A3 is shifted from the first axis A1 are the same. However, it is not limited to this. Further, in the solid-state imaging device 39 of FIG. 1, the amount of deviation in which the second axis A2 is deviated from the first axis A1 and the amount of deviation in which the third axis A3 is deviated from the first axis A1 are the same amount. Although it is an example, it is not limited to this.

  In short, when the photodiode DD is shifted so as to shift the third axis A3 with respect to the first axis A1, the in-layer lens IS is shifted so as to shift the second axis A2 with respect to the first axis A1. It is only necessary that the light transmitted through the in-layer lens IS reaches the photodiode DD that is displaced by being arranged. Therefore, the direction in which the second axis A2 deviates from the first axis A1 and the direction in which the third axis A3 deviates from the first axis A1 do not have to be completely coincident with each other. The amount of displacement by which the axis A2 is displaced may not be completely the same as the amount of displacement by which the third axis A3 is displaced with respect to the first axis A1.

  However, the reason why the in-layer lens IS is displaced is to guide the external light transmitted through the microlens MS to the light receiving surface of the photodiode DD. Therefore, if the direction in which the second axis A2 is displaced from the first axis A1 and the direction in which the third axis A3 is displaced from the first axis A1 are completely coincident with each other, the traveling direction of the intralayer lens IS transmitted light is determined. This is extremely desirable because it surely faces the light receiving surface of the photodiode DD.

  Even if the pitches of the in-layer lenses IS and the photodiodes DD are unevenly spaced, the pitches of the microlenses MS located on the pixel display surface are equally spaced (interval Ta). Therefore, the effective pixel pitch with respect to the incident light (incident image) is equally spaced. Therefore, it can be said that the solid-state imaging device 39 in which the color shading phenomenon is suppressed and the resolution is not deteriorated is realized.

[Embodiment 2]
A second embodiment of the present invention will be described. In addition, about the member which has the same function as the member used in Embodiment 1, the same code | symbol is attached and the description is abbreviate | omitted.

  Usually, the photodiode DD included in the pixel converts light into electric charges (electrons). The signal is expressed by the amount of this charge. Therefore, as shown in FIG. 3, the solid-state imaging device 39 includes a charge detection unit 21 that detects the amount of charge and a charge transfer unit (transfer) that transfers the charge converted by the photodiode DD to the charge detection unit 21. Gate) 22.

  In particular, the solid-state imaging device 39 also includes a signal amplifier 23 that enables output as a signal by amplifying a potential difference generated in the charge detector 21. Therefore, it can be said that the solid-state imaging device 39 is an amplification type having the signal amplification unit 23 that amplifies the electric signal generated by the photodiode DD. However, the number of signal amplifiers 23 is not particularly limited.

  Further, the arrangement positions of the elements such as the signal amplification unit 23, the charge detection unit 21, and the charge transfer unit 22 are not particularly limited. However, if a separate space is provided for arranging these elements, the solid-state imaging device 39 is increased in size. Therefore, it is desirable that these elements are arranged in a relatively large gap (gap space) in the pixel plane. For example, as illustrated in FIG. 3, these elements may be located in a gap space between the pixel group. In this case, even in the solid-state imaging device 39 corresponding to the recent increase in the number of pixels (that is, even the solid-state imaging device 39 having extremely small pixels), elements can be arranged. is there.

  Further, in the solid-state imaging device 39 having such a signal amplifying unit 23 (that is, the amplification type solid-state imaging device 39), the element such as the signal amplifying unit 23 is, for example, between photodiodes DD in adjacent pixel sets. It is arranged in a certain gap space. In this case, the photodiodes DD are electrically insulated from each other due to the presence of the signal amplifying unit 23 and the like. On the other hand, it can be said that some measure is necessary to surely insulate the photodiodes DD positioned so as to sandwich the gap space where the signal amplifier 23 and the like do not exist.

  An example of the measure is an element isolation layer 24 (halftone dot portion) formed by ion implantation of impurities (impurity diffusion material) (see FIG. 4). The element isolation layer 24 may be provided in at least a part of the gap space where the signal amplifier 23 does not exist. This is because the photodiodes DD are surely insulated from each other by the element isolation layer (element isolation section) 24 even if there is no element such as the signal amplification section 23.

  In particular, in the case where a pixel group is formed from pixels having photodiodes DD that are densely arranged by being displaced, it is desirable that the element isolation layer 24 be provided in a gap space in the pixel group. The element isolation layer 24 is usually easier to reduce in size and thickness than the element of the signal amplification unit 23. Therefore, if the element isolation layer 24 is arranged in the gap space between the closely spaced photodiodes DD in the pixel group, the gap space is extremely reduced even though the photodiodes DD are reliably insulated from each other. Pixels in the pixel set can be further densely packed. As a result, the solid-state imaging device 39 tends to be small even if it supports high pixel count.

  Since the element isolation layer 24 is formed by impurity implantation, it is not necessary to provide a field oxide film in the element isolation layer 24. Therefore, the thickness of the element isolation layer 24 (synonymous with the interval between adjacent photodiodes DD) is extremely thin, and the ratio (that is, the aperture ratio) of the light receiving area of the photodiode DD occupying the pixel area is increased.

[Other embodiments]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above, the solid-state imaging device 39 in which the distance Tb between the inner lenses IS and the distance Td between the photodiodes DD coincide, and further, the distance Tc between the inner lenses IS and the distance Te between the photodiodes DD coincide. (See FIG. 1). However, it is not limited to this. That is, the interval Tb and the interval Td may be different, and the interval Tc and the interval Te may be different.

  Further, as shown in FIGS. 3 and 4, a single signal amplifying unit 23 may be provided corresponding to one pixel set, or as shown in FIG. A plurality of signal amplifying units 23 may be provided. One or more signal amplifying units 23 may be provided corresponding to a plurality of pixel sets.

  Further, the number of pixel groups is not limited to four. For example, as shown in FIG. 6, it may be a pixel group composed of three pixels. Such a pixel group includes a pixel having a red color filter, a pixel having a green color filter, and a pixel having a blue color filter, as in the pixel group composed of four pixels. That is, a pixel set consisting of four pixels or a pixel set consisting of three pixels includes pixels having spectral characteristics corresponding to red, green, and blue color filters. Yes.

  If it is in this way, all the color information (white information) can be acquired for a pixel group as a unit. In other words, in the case of a pixel group consisting of four pixels, the spectral characteristics corresponding to the red, green, green, and blue color filters can be obtained even with a total of three pixels having spectral characteristics corresponding to the red, green, and blue color filters. All color information can be acquired even with a total of four pixels having. Further, in the case of a pixel group composed of three pixels, all color information can be acquired from all the pixels having spectral characteristics corresponding to the red, green, and blue color filters.

  Note that the pixel group composed of three pixels is arranged so as to be packed most closely in the plane. That is, as shown in FIG. 6, a pixel group having a triangular shape with three pixels is arranged while being alternately inverted in the horizontal direction (this arrangement may be referred to as a delta arrangement). ). However, even in such an arrangement, the microlenses MS are arranged at equal intervals, and the in-layer lens IS and the photodiode DD are arranged so as to approach the in-plane center of the pixel group. Therefore, the in-layer lenses IS and the photodiodes DD are arranged at unequal intervals as in the first and second embodiments.

  Although the third axis A3 of the photodiode DD is shifted from the first axis A1 of the microlens MS, the second axis A2 of the in-layer lens IS is shifted from the first axis A1 of the microlens MS. The light transmitted through the in-layer lens IS reaches the photodiode DD arranged in a shifted manner. Therefore, even in a pixel group consisting of three pixels, external light can reach the center of the light receiving surface of the photodiode DD, and all the photodiodes DD receive a uniform amount of light (uniform light intensity). become.

  Note that the solid-state imaging device 39 in FIG. 6 is an example in which the direction in which the second axis A2 is shifted from the first axis A1 and the direction in which the third axis A3 is shifted from the first axis A1 are the same. This is also an example in which the amount of deviation of the second axis A2 from the first axis A1 and the amount of deviation of the third axis A3 from the first axis A1 are the same amount.

  Various ways of taking the reference axes of the first axis A1 to the third axis A3 can be assumed. That is, the normal direction with respect to the surface vertex of the microlens MS passes through the first axis A1, the normal direction with respect to the surface vertex of the in-layer lens IS passes through the second axis A2, the center of the light receiving surface of the photodiode DD, and the method with respect to that surface. It is not limited to the way of taking the reference axis with the line direction as the third axis A3.

  For example, instead of the surface apex of the microlens MS or the in-layer lens IS, it may be the first axis A1 or the second axis A2 that goes from the peripheral edge of the lens toward the external light, or the light receiving surface of the photodiode DD. The third axis A3 may be the direction from the location in the plane other than the center toward the external light. Further, the direction of the reference axis toward the external light is not limited to the vertical direction. That is, the reference axis may be inclined.

  In short, any reference axis may be used as long as it can define the basic position and the displaced position of the microlens MS, the in-layer lens IS, and the photodiode DD. With such a reference axis, the in-plane arrangement of the microlens MS, the in-layer lens IS, and the photodiode DD can be defined, and it is clear whether these are arranged at equal intervals or at irregular intervals. This is because it can.

  A plurality of pixels having photodiodes DD arranged at unequal intervals in the in-plane arrangement, a microlens MS for collecting external light arranged at equal intervals in the in-plane arrangement, and light transmitted through the microlens MS In the solid-state imaging device 39 including the in-layer lens IS to be condensed, the external light transmitted through the microlens MS is transmitted through the in-plane lenses IS arranged at unequal intervals in the in-plane arrangement. It can be said that it can guide to the photodiode DD is an example of this invention.

These are a sectional view and a plan view of a solid-state imaging device. Is an optical path diagram showing the optical path of the external light incident on the solid-state imaging device, and (A) is an optical path diagram of the external light traveling in the same direction as the normal direction with respect to the surface vertex of the microlens. ) Is an optical path diagram of external light incident with an inclination (+ θ) with respect to the normal direction, and (C) is an optical path of external light incident with an inclination (−θ) opposite to the normal direction. FIG. These are the top views of the solid-state imaging device which specified various elements. These are the top views of the solid-state imaging device which specified the element isolation layer. FIG. 4 is a plan view of a solid-state imaging device showing another example of FIG. 3. FIG. 3 is a plan view showing a pixel group composed of three pixels. These are sectional drawings of the conventional solid-state imaging device. These are sectional drawing and the top view of the solid-state imaging device which show another example of FIG. FIG. 5 is a perspective view showing a position of an exit pupil with respect to a light receiving surface. Fig. 8 shows an optical path diagram in the solid-state imaging device of Fig. 8, wherein (A) is an optical path diagram of external light incident with an inclination (+ θx) with respect to the normal direction with respect to the surface vertex of the microlens; FIG. 4 is an optical path diagram of external light incident with an inclination (−θx) in a direction opposite to the normal direction.

Explanation of symbols

MS Microlens IS In-layer lens (internal lens)
DD photodiode (photoelectric converter)
A1 1st axis A2 2nd axis A3 3rd axis 11 Substrate 12 Interlayer insulation film 13 Flattening film 21 Charge detection part 22 Charge transfer part 23 Signal amplification part 24 Element isolation layer (element isolation part)
39 Solid-state imaging device

Claims (9)

With pixels having photoelectric conversion parts arranged at unequal intervals in the in-plane arrangement,
A microlens formed for each pixel, collecting external light arranged at equal intervals in an in-plane arrangement,
An internal lens formed for each pixel that collects light that passes through the microlenses arranged at unequal intervals in an in-plane arrangement and guides the light to the photoelectric conversion unit;
Including
A reference axis facing the external light is set for each of the microlens, the internal lens, and the photoelectric conversion unit, the reference axis of the microlens is a first axis, the reference axis of the internal lens is a second axis, When the reference axis of the conversion unit is the third axis,
The photoelectric conversion unit is arranged so as to be shifted so as to shift the third axis with respect to the first axis,
The internal lens is arranged so as to shift the second axis with respect to the first axis,
The direction in which the second axis deviates from the first axis matches the direction in which the third axis deviates from the first axis,
A solid-state imaging device in which the amount of deviation of the second axis with respect to the first axis is the same as the amount of deviation of the third axis with respect to the first axis. When each of the above pixels has spectral characteristics,
The solid-state imaging device according to claim 1, wherein a plurality of types of the pixels including pixels having different spectral characteristics are gathered to form a pixel set.   The solid-state imaging device according to claim 2, wherein all color information is acquired in at least some of the pixels in the pixel set.   4. The solid-state imaging device according to claim 2, further comprising a signal amplifying unit that amplifies an electric signal generated by the photoelectric conversion unit. 5. The solid-state imaging device according to claim 4 , wherein one or a plurality of the signal amplification units are provided corresponding to one or a plurality of the pixel sets. When the signal amplification unit is arranged in a gap space between the photoelectric conversion units,
6. The solid-state imaging device according to claim 4, wherein an element separation unit that electrically insulates the photoelectric conversion units is provided in the gap space where the signal amplification unit does not exist.   The solid-state imaging device according to claim 6, wherein the element separation unit is provided in the gap space in the pixel group.   The solid-state imaging device according to claim 6, wherein the element isolation portion is made of an impurity diffusion material.   The solid-state imaging device according to claim 2, wherein the in-plane arrangement of the pixel group is an arrangement of 2 rows and 2 columns.

Images