JP2010074218A - Solid-state image pickup element and method of manufacturing the same, and image pickup apparatus using the solid-state image pickup element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state image pickup element having a waveguide structure and suppressed in shading: a method of manufacturing the same: and an image pickup apparatus using the solid-state image pickup element. <P>SOLUTION: The solid-state image pickup element has a structure in which the center position of a microlens 12, the center position of a color filter 10, the opening center position of a light-shielding layer 6 and the entrance center position of a waveguide 15 are shifted from the center of a corresponding light-receiving element to the center direction of an effective image pickup region. The shift amount is set by multiplying an aberration correcting coefficient (a) to an assumed shift amount obtained from the difference between the position of a light on an optical path obtained by assuming that the light is refracted in accordance with the difference in refractive index between the materials of both sides of boundaries and has an optical path to the center of a light-receiving element 3 and the position corresponding to the center of the light-receiving element, in a boundary where a main light incident from the center of an exit pupil of the camera lens to the center position of each microlens 12 is incident on the microlens 12 and a boundary of each material layer on the optical path where the light reaches from the microlens 12 to the light-receiving element 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device and an imaging apparatus, and in particular, a solid-state imaging device in which a plurality of light-receiving elements and a minute condenser lens (microlens) are arranged, a manufacturing method thereof, and imaging using the solid-state imaging device Relates to the device.

In recent years, digital cameras and video cameras that capture still images and moving images have become widespread in various fields. These cameras incorporate a solid-state imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) that records an image by converting subject light into a photoelectric signal. The structure of the solid-state imaging device includes, for example, a light receiving element that receives subject light and converts it into a photoelectric signal, a color filter layer formed on the light receiving element, and a microlens for improving the light collection rate on the light receiving element. It is equipped with.
In such a solid-state imaging device, a phenomenon called shading occurs in which the signal output at the peripheral portion is attenuated (sensitivity is lowered) as compared with the central portion of the effective imaging region. This shading is due to the fact that incident light is obliquely incident on the periphery of the effective imaging region and the light use efficiency is reduced. Conventionally, in order to prevent shading, in consideration of the chief ray incident angle from the camera lens, the microlens is arranged at the position of the light receiving element at the center of the effective imaging area, and the microlens is arranged at the periphery of the effective imaging area. Shifting from the light receiving element toward the center of the effective imaging area is performed. With regard to the setting of this shift amount, the light that enters the center of the microlens from the exit pupil center of the camera lens is traced based on Snell's law, and the microlens is made so that the light enters the center of the light receiving element. A method for determining the shift amount is disclosed (Patent Documents 1 and 2).

On the other hand, miniaturization of pixel dimensions accompanying the recent increase in the number of pixels causes another problem such as reduction in the size of the light receiving element and reduction in sensitivity. Correspondingly, a waveguide structure that applies total reflection at the interface between a transparent high-refractive-index substance and a low-refractive-index substance as a means for effectively guiding the light collected by the microlens to the light-receiving element The technique to form in is proposed. The above-described shading phenomenon also occurs in the solid-state imaging device provided with this waveguide. As a countermeasure, the microlens, the waveguide itself, and the waveguide opening are shifted from the light-receiving element to the center of the effective imaging region. It has been proposed to arrange them and to change the cross-sectional shape of the waveguide (Patent Documents 3 to 6).
JP 2003-18476 A JP 2001-160973 A JP 2005-259824 A JP 2006-261249 A JP 2006-324439 A JP 2006-295125 A

  However, in the conventional anti-shading techniques disclosed in Patent Documents 1 and 2, the influence of coma aberration that occurs when the incident angle of the light incident on the microlens is large (that is, the periphery of the effective imaging region) is considered. However, since the shift amount is set only by simple ray tracing, there is a problem that shading is not sufficiently suppressed. Further, Patent Document 2 discloses that a shift amount is obtained by a calculation that omits simple ray tracing, and a range of ± 30% is allowed. However, this error of ± 30% is recognized in consideration of calculation omissions and approximations and actual manufacturing accuracy, and is positively on the -30% side or on the + 30% side. It is not a technical matter to do.

On the other hand, Patent Documents 3 to 6 do not show how to set the shift of the waveguide or the like. If the shift amount is set in the same manner as Patent Documents 1 and 2, the waveguide is It does not consider how it affects shading prevention. In addition, a metal wiring layer and a metal light shielding layer are disposed around the waveguide of the CMOS device. However, in order to shift the waveguide, it is also necessary to shift them together. The shift is performed including the conduction portion between the upper and lower wiring layers. For this reason, some shifts and design changes are required for most layers constituting the CMOS device. This means that a dedicated design for the CMOS device is required for each customer and for each camera lens, and the design man-hours increase. However, there has been a problem that the manufacturing cost is increased due to the small production lot.
The present invention has been made in view of the above circumstances, and provides a solid-state imaging device having a waveguide structure in which shading is suppressed, a manufacturing method thereof, and an imaging apparatus using the solid-state imaging device. With the goal.

  In order to achieve such an object, the present invention provides a plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to the individual light receiving elements, and the individual light receiving elements. A color filter in which a red filter, a green filter, and a blue filter are arranged in correspondence with each other, and a microlens array in which a plurality of microlenses are two-dimensionally arranged in correspondence with each of the light receiving elements. Are arranged in the order of the microlens array, the color filter, the waveguide, and the light receiving element from the light incident side, and the microlens has a characteristic that causes coma aberration on the optical axis side of the microlens. The center position of the micro lens, the center position of each color filter, and the center position of the entrance of each waveguide are closer to the effective imaging area than the center of the corresponding light receiving element. Shifting in the central direction, the amount of shift reaches the boundary where the chief ray incident on the center position of each microlens from the center of the exit pupil of the camera lens enters the microlens, and reaches the light receiving element from the microlens On the optical path of the light beam obtained on the assumption that an optical path that is refracted corresponding to the difference in refractive index of the material on both sides of the boundary and takes the optical path to the center of the light receiving element is taken at each boundary of each material layer on the optical path And an assumed shift amount obtained from the difference between the position corresponding to the center of the light receiving element and the aberration correction coefficient a, which is set to 0.39 ≦ a ≦ 1.26. It was set as the structure which is a range.

As another aspect of the present invention, when the laminated structure located on the light incident side from the light receiving element is an M layer structure, and the microlens located closest to the light incident side is the first layer, the first layer to the N layer The assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting to the first (1 ≦ N ≦ M) is expressed by the following equation (1).
Si = Σ _{j = i} ^M d _j tan θ _j (1)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = ray angle of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the incident angle of the chief ray incident on
Set in
The shift amount Si actual of the i-th layer (i = 1, 2,..., N) is expressed by the following equation (2).
Si actual = a × Si (2)
Where a is an aberration correction coefficient,
It was set as the structure represented by these.

  In addition, the present invention provides a plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to the individual light receiving elements, and a red filter, green corresponding to each light receiving element. A filter, a color filter in which blue filters are arranged, and a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements. Arranged in the order of color filters, waveguides, and light receiving elements, and the microlens has a characteristic of generating coma on the optical axis side of the microlens, in the center position of each microlens, or The center position of each microlens and the center position of each color filter are closer to the center of the effective imaging area than the center of the corresponding light receiving element. The amount of shift is determined by the light from the center of the exit pupil of the camera lens to the center of each microlens where the principal ray enters the microlens and the light from the microlens to the light receiving element. At each boundary of each material layer on the path, the position of the light beam on the optical path obtained by assuming that it takes an optical path that refracts corresponding to the difference in refractive index of the material on both sides of the boundary and reaches the entrance center of the waveguide; The estimated shift amount obtained from the difference from the position corresponding to the center of the light receiving element is set by multiplying the aberration correction coefficient a, and only the center position of each microlens is more effective than the center of the corresponding light receiving element. The aberration correction coefficient a when shifting toward the center of the region is in the range of 0.46 ≦ a ≦ 0.81, and the center position of each microlens and the center position of each color filter are Is the aberration correcting coefficient a during the shifting in central direction of the effective image pickup area of the center of the response to the light receiving element has a structure such that the range of 0.59 ≦ a ≦ 1.34.

As another aspect of the present invention, the laminated structure located on the light incident side from the light receiving element is an M layer structure, the microlens located closest to the light incident side is the first layer, and the waveguide entrance is the M ′ layer ( Assuming that M ′ ≦ M), the assumed shift of the i-th layer (i = 1, 2,..., N) when shifting from the first layer to the N-th layer (1 ≦ N <M ′). The quantity Si is given by the following formula (3)
Si = Σ _{j = i} ^M′−1 d _j tan θ _j (3)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M′-1-th layer,
θ _j = ray angle of the j-th layer located between the i-th layer and the M′−1-th layer
And
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the incident angle of the chief ray incident on
Set in
The shift amount Si actual of the i-th layer (i = 1, 2,..., N) is expressed by the following equation (4).
Si actual = a × Si (4)
Where a is an aberration correction coefficient,
It was set as the structure represented by these.

  In addition, the present invention provides a plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to the individual light receiving elements, and a red filter, green corresponding to each light receiving element. A filter, a color filter in which blue filters are arranged, and a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements. In the method of manufacturing a solid-state imaging device, the center position of each microlens is arranged in the order of a color filter, a waveguide, and a light receiving element, and the microlens has a characteristic of generating coma on the optical axis side of the microlens And the center position of each color filter and the center position of the entrance of each waveguide are located closer to the center of the effective imaging area than the center of the corresponding light receiving element. The principal ray incident from the center of the exit pupil of the camera lens to the center position of each microlens enters the microlens and the light from the microlens to the light receiving element. At each boundary of each material layer on the path, the position on the optical path of the light beam that is obtained assuming that it takes an optical path that refracts corresponding to the difference in refractive index of the material on both sides of the boundary and reaches the center of the light receiving element; A value obtained by multiplying the assumed shift amount obtained from the difference from the position corresponding to the center of the light receiving element by the aberration correction coefficient a1 and the aberration correction coefficient a2 is obtained, and the two kinds of values for each pixel are determined as Y. A curve formed by a value obtained by multiplying the aberration correction coefficient a1 and a value obtained by multiplying the aberration correction coefficient a2 on a graph in which the axis is plotted on the X axis with the number of pixels having the center of the effective imaging area as the zeroth. Of the sandwiched area The shift amount is set so as to be on a straight line, and the aberration correction coefficient a1 and the aberration correction coefficient a2 are in the range of 0.39 to 1.26 and have a relationship of a1 <a2. It was.

As another aspect of the present invention, when the laminated structure located on the light incident side from the light receiving element is an M layer structure, and the microlens located closest to the light incident side is the first layer, the first layer to the N layer The assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting to the first (1 ≦ N ≦ M) is obtained from the following equation (5). .
Si = Σ _{j = i} ^M d _j tan θ _j (5)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = ray angle of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.

  In addition, the present invention provides a plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to the individual light receiving elements, and a red filter, green corresponding to each light receiving element. A filter, a color filter in which blue filters are arranged, and a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements. In the method of manufacturing a solid-state imaging device, the center position of each microlens is arranged in the order of a color filter, a waveguide, and a light receiving element, and the microlens has a characteristic of generating coma on the optical axis side of the microlens And the center position of each color filter are shifted by a predetermined shift amount from the center of the corresponding light receiving element toward the center of the effective imaging area. The principal ray incident at the center position of each microlens from the center of the exit pupil of the camera lens is incident on the microlens, and each material layer on the optical path from the microlens to the light receiving element At each boundary, the light beam is refracted corresponding to the difference in the refractive index of the material on both sides of the boundary and takes the optical path leading to the entrance center of the waveguide, and the position of the light beam on the optical path and the center of the light receiving element. A value obtained by multiplying the assumed shift amount obtained from the difference from the corresponding position by the aberration correction coefficient a1 and the aberration correction coefficient a2 is obtained, and effective imaging is performed with the two values for each pixel as the Y axis. On the graph in which the number of pixels with the center of the area 0 is plotted on the X-axis, the area between the curve formed by the value multiplied by the aberration correction coefficient a1 and the curve formed by the value multiplied by the aberration correction coefficient a2 Ride on any straight line It sets the shift amount, the aberration correction coefficient a1 and the aberration correction factor a2 is with in the range of 0.59 to 1.34, and configured as a relationship of a1 <a2.

As another aspect of the present invention, the laminated structure located on the light incident side from the light receiving element is an M layer structure, the microlens located closest to the light incident side is the first layer, and the waveguide entrance is the M ′ layer ( Assuming that M ′ ≦ M), the assumed shift of the i-th layer (i = 1, 2,..., N) when shifting from the first layer to the N-th layer (1 ≦ N <M ′). The quantity Si was configured to be obtained from the following equation (6).
Si = Σ _{j = i} ^M′−1 d _j tan θ _j (6)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M′-1-th layer,
θ _j = ray angle of the j-th layer located between the i-th layer and the M′−1-th layer
And
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.

  The imaging device of the present invention is configured to include the above-described solid-state imaging device of the present invention.

  Such a solid-state imaging device of the present invention has a microlens, a color filter, and a waveguide, assuming an optical path from the principal ray incident on the center position of each microlens from the center of the exit pupil of the camera lens to the center of the light receiving device. The shift amount is set by multiplying the assumed shift amount by the aberration correction coefficient a in consideration of the coma aberration of the microlens that is not taken into consideration in the shifted conventional solid-state imaging device. The shading is effectively suppressed.

The method for manufacturing a solid-state imaging device according to the present invention can be applied to an effective imaging region by using a microlens, a color filter, and a waveguide shift amount even when a camera lens having a nonlinear relationship between an image height and a chief ray incident angle is used. Therefore, it is not necessary to make a non-linear change from the center to the peripheral part, and it is possible to easily manufacture a solid-state imaging device in which shading in the peripheral part of the effective imaging region is effectively suppressed.
The image pickup apparatus of the present invention has a high quality with little loss of vignetting caused by oblique incidence and a low efficiency distribution with respect to the amount of incident light, and can be reduced in size and thickness.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Solid-state imaging device]
FIG. 1 is a schematic configuration diagram showing an embodiment of a solid-state imaging device of the present invention. In FIG. 1, a solid-state imaging device 1 includes a plurality of light receiving elements 3 two-dimensionally arranged on a substrate 2 at a constant arrangement pitch, an insulating layer 7 having wiring layers 4 and 5 and a light shielding layer 6, and the insulating layer 7. A passivation layer 8, a lower planarization layer 9, a color filter 10, an upper planarization layer 11, and a microlens 12 are sequentially provided on the top. In addition, a waveguide 15 is provided in the insulating layer 7 corresponding to each light receiving element 3.

  The substrate 2 is a silicon substrate, and the light receiving element 3 may be a known photodiode in which a pn junction is formed, and is usually arranged in a square lattice shape. The wiring layers 4 and 5 are for transferring signal charges generated by the light receiving element 3 which is a photodiode. The light shielding layer 6 has a plurality of openings arranged corresponding to the individual light receiving elements 3 and may be formed of a light shielding metal layer (for example, Al, Al / Si / Cu alloy, etc.). it can. In the present invention, the light shielding layer 6 is provided closest to the color filter 10 among the pattern layers made of a light shielding material such as metal provided between the color filter 10 of the solid-state imaging device and the light receiving device 3. Say the pattern. Usually, the light shielding layer 6 is often in a lattice shape having an opening corresponding to the light receiving element 3 in plan view, but includes a case in which the light shielding layer 6 has a stripe shape without a closed opening shape. The light shielding layer 6 may also serve as a wiring layer.

The insulating layer 7 is made of a transparent film such as silicon oxide formed by the CVD method, for example, and is formed so as to cover the light receiving element 3. The insulating layer 7 has a multilayer structure in which the wiring layers 4 and 5 and the light shielding layer 6 are disposed inside, and the insulating layer 7a closest to the microlens 12 is between the passivation layer 8 and the waveguide 15. positioned. In the example of FIG. 1, the positional relationship between the light shielding layer 6 and the waveguide 15 is such that the surface of the opening of the light shielding layer 6 on the microlens side is in the same plane as the entrance of the waveguide 15. It is not limited to. Therefore, the microlens side surface of the opening of the light shielding layer 6 may be closer to the microlens 12 than the entrance of the waveguide 15 or may be closer to the light receiving element 3. The passivation layer 8 can be formed of silicon nitride, silicon dioxide, or the like, and the lower planarization layer 9 can be formed of a resin material.
The color filter 10 includes a red filter 10 </ b> R, a green filter 10 </ b> G, and a blue filter 10 </ b> B, and each color filter corresponds to each light receiving element 3.

The upper flattening layer 11 covers the color filter 10 to form a flat surface, and enables the formation of a microlens array 13 composed of homogeneous microlenses 12 having equivalent light collection properties. Such an upper planarization layer 11 can be formed of a resin material.
The microlens array 13 includes a plurality of microlenses 12 formed corresponding to the color filters of the light receiving elements 3 and the color filters 10. Since the microlens 12 is formed on the upper planarization layer 11, it is convex on the light incident side and has a characteristic of generating coma on the optical axis side. The shape of the microlens 12 may be, for example, a shape obtained by cutting out a part of a spheroid, and may be a shape having no gap at the boundary between adjacent microlenses, but is not limited thereto.

The method for forming the microlens array 13 composed of the microlenses 12 is not particularly limited. For example, a positive photoresist is used as the microlens material, and the photoresist is post-baked after the photolithography steps of application, exposure, and development. Can be melted and molded into a convex lens shape. The microlens formation method that melts and forms a convex lens in this way is a formation method that always requires a gap between the microlenses. In addition, a fine dot pattern that does not resolve at the exposure wavelength, and is exposed and developed through a gradation photomask that expresses the three-dimensional shape of the microlens as a gradation, resulting in a shape expressed in gradation by fine dots. Can be formed on the photoresist layer to form the microlens 12. With this method, it is possible to form an efficient microlens without a gap between the microlenses.
The waveguide 15 is means for effectively guiding the light beam collected by the microlens 12 to the light receiving element 3, and each waveguide 15 corresponds to each light receiving element 3. The waveguide 15 is made of a transparent material having a refractive index higher than that of the insulating layer 7, for example, silicon nitride.

  The solid-state imaging device 1 is arranged in the order of the microlens array 13, the color filter 10, the light shielding layer 6, the waveguide 15, and the light receiving element 3 from the light incident side, and on the microlens side of the opening of the light shielding layer 6. The surface is flush with the entrance of the waveguide 15. However, as described above, the relationship between the light shielding layer 6 and the entrance of the waveguide 15 is not limited to this. The microlens 12 has a characteristic that causes coma aberration on the optical axis side. In such a solid-state imaging device 1 of the present invention, the center position of each microlens 12 or the center position of each microlens 12 and the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B). Alternatively, the center position of each micro lens 12, the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B), the opening center position of each light shielding layer 6, and the entrance center position of each waveguide 15. Is shifted from the center of the corresponding light receiving element 3 toward the center of the effective imaging region. The setting of the shift amount will be described below.

  First, the center position of each microlens 12, the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) and the entrance center position of each waveguide 15 are determined from the center of the corresponding light receiving element 3. A case where the image is also shifted toward the center of the effective imaging area will be described. In this case, the principal ray that has entered the center position of each microlens 12 from the center of the exit pupil of the camera lens is incident on the microlens 12 and each path on the optical path from the microlens 12 to the light receiving element 3. It is assumed that at each boundary of the material layer, an optical path that refracts corresponding to the difference in refractive index between the materials on both sides of the boundary and reaches the center of the light receiving element 3 is taken. The shift amount is set by multiplying the assumed shift amount obtained from the difference between the position on the optical path of the light beam obtained from this assumption and the position corresponding to the center of the light receiving element 3 by the aberration correction coefficient a. In the present invention, the shift of the waveguide shifts the light incident side (waveguide entrance) and does not shift the light receiving element 3 side.

Here, the assumed shift amount will be described. FIG. 2 is a diagram for explaining an optical path from a light beam incident on a microlens to a light receiving element. As shown in FIG. 2, the microlens 12, the upper planarizing layer 11, the color filter 10, the lower planarizing layer 9, the passivation layer 8, the insulating layer 7a, the waveguide 15, and the light receiving element 3 are arranged in this order from the light incident side. It is installed. The wiring layers 4 and 5 are disposed outside the optical path, and are omitted because they are not necessary for explanation of the optical path. Here, the microlens 12 and the functional layer (each layer positioned between the light receiving element 3 and the microlens 12) are collectively used as an M layer laminated member, and the microlens 12 positioned closest to the light incident side is the first layer. And Further, n ₀ is the refractive index of the atmosphere (n ₀ = 1.0), n ₁ is the refractive index of the microlens, and θ ₀ is the principal ray incident from the center of the exit pupil of the camera lens to the center of the microlens. An angle, and θ ₁ is an emission angle of a chief ray emitted from the microlens. Further, as described above, at each boundary of each material layer on the optical path from the microlens 12 to the light receiving element 3, the light is refracted corresponding to the difference in the refractive index of the material on both sides of the boundary, and the center of the light receiving element 3 Assuming that the optical path leading to is taken, n ₀ , n ₁ , θ ₀ , and θ ₁ have the following relationship according to Snell's law. In FIG. 2, the optical axis of the camera lens (the center of the imaging area) is located on the left side (in the direction of the center of the effective imaging area) with respect to the center of the light receiving element 3.
Since n ₀ sin θ ₀ = n ₁ sin θ _1, θ ₁ = sin ⁻¹ ((n ₀ / n ₁ ) sin θ ₀ ).

Similarly, θ _{j at} the interface between the j-1 layer and the j layer (the emission angle of the principal ray emitted from the j layer) is θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ). It becomes.
Further, since the shift amount dS _{1 of the} microlens 12 (the shift amount of the microlens 12 with respect to the second upper planarizing layer 11) is dS ₁ / d ₁ = tan θ ₁ , dS ₁ = d ₁ tan θ ₁ It becomes.
Similarly, the shift amount dS _{j from} the j layer to the j + 1 layer is dS _j = d _j tan θ _j .

The accumulation of the shift amount dS _j from the i-th layer (i = 1, 2,..., M) to the M-th layer shifts from the first layer to the N-th layer (1 ≦ N ≦ M). The assumed shift amount Si of the i-th layer (i = 1, 2,..., N) at the time is expressed by the following formula (1).
Si = Σ _{j = i} ^M d _j tan θ _j (1)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = ray angle of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.
The refractive index is measured using a spectroscopic ellipsometer. The same applies to the following present invention.

In the illustrated example, M = N = 7, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁷ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁷ d _j tan θ _j . Further, the assumed shift amount S7 of the waveguide 15 with i = 7 is S7 = d ₇ tan θ ₇ . Here, as in the configuration shown in FIG. 1, if the microlens side surface of the opening of the light shielding layer 6 exists in the same plane as the entrance of the waveguide 15, the opening center position of the light shielding layer 6 and the waveguide 15 The assumed shift amount at the entrance center position is an assumed shift amount S7 obtained when i = 7. The waveguide 15 has a high refractive index material portion and a low refractive index material portion, but the region through which the principal ray passes is a high refractive index material portion. Consider the rate.
In the present invention, the shift amount is set by multiplying the assumed shift amount thus obtained by the aberration correction coefficient a, and the shift amount Si actual of the i-th layer (i = 1, 2,..., N). Is represented by the following formula (2). Here, a is an aberration correction coefficient.
Si actual = a × Si (2)

Here, an assumed shift amount when the microlens side surface of the opening of the light shielding layer 6 is not flush with the entrance of the waveguide 15 will be described. First, in the case where the microlens side surface of the opening of the light shielding layer 6 is on the microlens side from the entrance of the waveguide 15, for example, as shown in FIG. And what is necessary is just to assemble the said Formula (1) and Formula (2). In the example of FIG. 20, M = N = 8, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁸ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁸ d _j tan θ _j . Further, the assumed shift amount S7 of the light shielding layer 6 with i = 7 is S7 = Σ _{j = 7} ⁸ d _j tan θ _j . Further, the assumed shift amount S8 of the waveguide 15 with i = 8 is S8 = d ₈ tan θ ₈ . Next, when the microlens side surface of the opening of the light shielding layer 6 is on the light receiving element side from the entrance of the waveguide 15, for example, as shown in FIG. 21. In this example, M = N = 9, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁹ d _j tan θ _j . Further, assume the shift amount S3 of the color filter 10 of i = 3 becomes ^{_{S3 = Σ j = 3 9 d}} j tanθ j. Further, assume the shift amount S7 in waveguide 15 i = 7 (inlet) becomes ^{_{S7 = Σ j = 7 9 d}} j tanθ j. Furthermore, the assumed shift amount S8 of the light shielding layer 6 with i = 8 is S8 = Σ _{j = 8} ⁹ d _j tan θ _j . At this time, the waveguide 15 extends over three layers of i = 7 to 9, but is substantially continuous. Further, in the shift of the entrance portion of the waveguide 15 and the light shielding layer 6, the refractive index of the high refractive index material portion of the waveguide 15 may be taken into consideration.

Next, the center position of each micro lens 12 or the center position of each micro lens 12 and the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) corresponds to the corresponding light receiving element 3. A case where the center of the effective imaging area is shifted from the center will be described. In this case, the principal ray that has entered the center position of each microlens 12 from the center of the exit pupil of the camera lens is incident on the microlens 12 and each path on the optical path from the microlens 12 to the light receiving element 3. It is assumed that at each boundary of the material layer, an optical path is refracted corresponding to the difference in the refractive index of the material on both sides of the boundary and reaches the entrance center of the waveguide 15. Under such an assumption, the chief ray is not collected at the center of the light receiving element 3, but even if the optical path is off the center of the light receiving element 3, the waveguide 15 functions and is guided to any part of the light receiving element 3. It is burned.
Also in this case, as in the above case, the shift amount dS _j of the _j layer with respect to the j + 1 layer is dS _j = d _j tan θ _j .

The laminated structure positioned on the light incident side from the light receiving element 3 is an M layer structure. The microlens 12 positioned closest to the light incident side is the first layer, and the entrance of the waveguide 15 is the M ′ layer (M ′ ≦ M), and the shift amount from the i-th layer (i = 1, 2,..., N) to the N-th layer when shifting from the first layer to the N-th layer (1 ≦ N <M ′) The accumulation of dS _j is the assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting from the first layer to the N-th layer (1 ≦ N <M ′). It is represented by the following formula (3).
Si = Σ _{j = i} ^M′−1 d _j tan θ _j (3)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M′−1 layer,
θ _j = ray angle of the j-th layer located between the i-th layer and the M′−1-th layer
And
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.

In the layer configuration shown in FIG. 2, M = M ′ = 7, N = 6, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁶ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁶ d _j tan θ _j .
At this time, if the microlens side surface of the opening of the light shielding layer 6 is in the same plane as the entrance of the waveguide 15, or is located on the light receiving element 3 side from the same plane, the opening of the light shielding layer 6 is shifted. Not. On the other hand, when the microlens side surface of the opening of the light shielding layer 6 is on the microlens side from the entrance of the waveguide 15, for example, as shown in FIG. And what is necessary is just to assemble said Formula (3). In the number of layers in FIG. 20, M = M ′ = 8 and N = 7, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁷ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁷ d _j tan θ _j . The assumed shift amount S7 of the light shielding layer 6 with i = 7 is S7 = d ₇ tan θ ₇ .

In the present invention, the shift amount is set by multiplying the assumed shift amount thus obtained by the aberration correction coefficient a, and the shift amount Si actual of the i-th layer (i = 1, 2,..., N). Is represented by the following formula (4). Here, a is an aberration correction coefficient.
Si actual = a × Si (4)

Next, the aberration correction coefficient a will be described.
FIG. 3 is a diagram illustrating a state in which parallel light incident on the microlens at an incident angle of 20 ° is collected on the light receiving element. As shown in FIG. 3, the microlens 12, the upper planarizing layer 11, the color filter 10, the lower planarizing layer 9, the passivation layer 8, the insulating layer 7a, the waveguide 15, and the light receiving element 3 are arranged in this order from the light incident side. It is installed. Then, the center position of each microlens 12, the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) and the entrance center position of each waveguide 15 can be obtained from the above equation (1). The shift is performed based on the assumed shift amount. Further, the upper planarization layer 11, the lower planarization layer 9, the passivation layer 8, and the insulating layer 7a that are substantially continuous between adjacent pixels are also shifted based on the assumed shift amount obtained from the above equation (1). It is regarded as a thing. Of course, the thickness, refractive index, and curvature of the microlens 12 of each of these layers are designed so as to collect light at one point of the light receiving element 3 when the incident angle of the principal ray incident on the microlens 12 is 0 °. . As shown in FIG. 3, when the incident angle to the microlens 12 is increased, the light is not condensed on one point of the light receiving element 3, but below the arrival point of the principal ray incident on the center of the microlens 12 ( In the direction indicated by the arrow in FIG. 3, that is, the light beam reaches the center of the effective imaging region with a deviation, and coma occurs.

Although the opening of the light shielding layer 6 is not shown in FIG. 3, the microlens side surface of the opening of the light shielding layer 6 is connected to the microlens 12 from the entrance of the waveguide 15 as described in the description of FIG. The assumed shift amount is calculated according to whether the light is on the light receiving element 3 side or the light receiving element 3 side, and the shift is based on the calculated amount.
FIG. 4 shows a case where a light beam (chief ray incident angle 20 °) incident from a camera lens having an F value = 2.8 reaches the entrance of the waveguide 15 in a state where coma occurs as shown in FIG. FIG. 8 is a diagram showing a relative incident light intensity level at the entrance surface of the waveguide 15, and the lower side corresponds to the lower side of FIG. 3. FIG. 5 shows a state in which coma occurs as shown in FIG. 3, and a light beam (chief ray incident angle of 30 °) incident from a camera lens having an F value = 2.8 reaches the entrance of the waveguide 15. FIG. 6 is a diagram showing a relative incident light intensity level at the entrance surface of the waveguide 15 in the case where the lower side corresponds to the lower side of FIG. 3. The incident light intensity levels shown in FIG. 4 and FIG. 5 are based on the assumed shift amount obtained from the above equation (1), the center position of each microlens 12, the center position of each color filter 10, and each guide. This is a relative incident light intensity level when the center position of the entrance of the waveguide 15 is shifted. The spread of the light beam incident from the camera lens is distorted in the vertical direction, and the spread of the light beam passes through the center of the microlens 12. It spreads below the point (indicated by a cross in the figure) where the light ray to reach, that is, toward the center of the effective imaging area.

  Here, the center of the region having a relatively high incident light intensity level is on the upper side in the drawing, and the center of the region having a relatively low incident light intensity level is on the lower side in the drawing. Therefore, in order to make the incident light beam efficiently enter the entrance of the waveguide 15, the entrance center of the waveguide 15 is shifted upward in FIGS. 4 and 5 from the passing point of the principal ray passing through the center of the microlens. It is necessary to consider whether it should be shifted or shifted downward. According to the examination results in the present invention, the center position of each microlens and the center position of each color filter and the entrance center position of each waveguide, or the center position of each microlens and the center position of each color filter, However, when the center of the effective image pickup region is shifted from the center of the corresponding light receiving element toward the center of the effective imaging region, the position of the entrance center of the waveguide is more than that of the principal ray passing through the center of the microlens. 5, it was found that there was redundancy that allowed a certain amount of misalignment in the vertical direction.

In addition, when only the center position of each microlens is shifted from the center of the corresponding light receiving element toward the center of the effective imaging region, the position of the entrance center of the waveguide is the principal ray passing through the center of the microlens. It has been found that it is preferable to shift downward in FIG. 4 and FIG. This is because the center of the region of the value of the aberration correction coefficient a that can maintain a high hit rate is less than 1 (less than 100%) as shown in FIG. This is because when the incident angle increases, the shift amount is set so that the principal ray passing through the center of the microlens passes through the entrance center of the waveguide. It is shown that it cannot be made incident on.
The chief ray incident angle is 0 ° at the center of the effective imaging area, and increases as it goes toward the periphery of the effective imaging area. Generally, the chief ray incident angle at the outermost peripheral portion of the effective imaging region is about 20 °, but the chief ray incident angle at the outermost peripheral portion of the effective imaging region is further increased due to the downsizing and thinning of the camera. A camera using a camera lens having a chief ray incident angle close to 30 ° should also be considered in the present invention.

  Here, the above-described formulas (1) and (2) are applied to the laminated structure shown in FIG. 3, and the center position of each microlens 12 and each color filter 10 (red filter 10R, green filter 10G, blue filter 10B). ) And the entrance center position of each waveguide 15 are calculated as shown in FIG. FIG. 6 is a diagram showing a state in which the principal ray incident on the center position of the microlens reaches the light receiving element at an incident angle of 20 °. As shown in FIG. 6, the microlens 12, the upper planarizing layer 11, the color filter 10, the lower planarizing layer 9, the passivation layer 8, the insulating layer 7a, the waveguide 15, and the light receiving element 3 are arranged in this order from the light incident side. It is installed. Then, the center position of each microlens 12, the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) and the entrance center position of each waveguide 15 can be obtained from the above equation (1). The shift is performed based on the assumed shift amount. Further, the upper planarization layer 11, the lower planarization layer 9, the passivation layer 8, and the insulating layer 7a that are substantially continuous between adjacent pixels are also shifted based on the assumed shift amount obtained from the above equation (1). It is regarded as In this case, the principal ray optical path is assumed to be an optical path that passes through the entrance center of the waveguide 15 and reaches the exit center of the waveguide 15 (center of the light receiving element 3). The shift amount is calculated by multiplying the assumed shift amount obtained for each layer by the same value of the aberration correction coefficient a, and various shift amounts are calculated by changing the value of the aberration correction coefficient a. is doing. Then, shifting is performed based on the calculated shift amount, and the energy at which the light beam incident on the microlens 12 from the camera lens having the F value = 2.8 under the condition of the chief ray incident angle of 30 ° reaches the light receiving element 3 is obtained. A value obtained by optical simulation of the relative ratio to the input energy is shown in FIG. 7 as an energy hit rate. Note that the input energy is the energy when incident on the surface of the microlens 12 at a chief ray incident angle of 0 ° regardless of the chief ray incident angle.

  As shown in FIG. 7, when the value of the aberration correction coefficient a is in the range of 39% to 126%, the energy hit ratio of 95% or more of the maximum energy hit ratio when the value of the aberration correction coefficient a is changed is maintained. be able to. Further, when the value of the aberration correction coefficient a is in the range of 44% to 116%, 99% or more of the maximum energy hit rate can be maintained. From this result, the shift amount (S1 actual) of the center position of each microlens 12, the shift amount (S3 actual) of the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) and each waveguide. The aberration correction coefficient a when the shift amount (S7 actual) of the 15 entrance center position is obtained from the above equations (1) and (2) is 0.39 ≦ a ≦ 1.26. Here, regarding the shift of the opening of the light shielding layer 6 shown in FIG. 1, as described in FIG. 2, the microlens side surface of the opening of the light shielding layer 6 is closer to the microlens 12 than the entrance of the waveguide 15. It is sufficient to calculate the assumed shift amount at the center of the aperture and multiply it by the aberration correction coefficient a. In addition, the value of a used for calculation of each shift amount (S1 actual, S3 actual, S7 actual) may be in the above range, and it is not necessary to use the same value common to all the layers to be shifted. .

Here, in the present invention, ZEMAX-EE (Version April 2, 2004 rev.b) manufactured by ZEMAX Development Corpotation is used as software for performing optical simulation. The calculation result (efficiency) on the software (ZEMAX) is processed as energy taking into account the incident angle to the light receiving element, not simply the ratio of the number of input light rays and the number of light rays reaching the light receiving element. . That is, each light beam reaching the light receiving element is multiplied by cos θ (θ is an incident angle) to be treated as energy, and expressed as efficiency compared to the energy of input light. The energy hit ratio is a ratio E ₂ / energy E ₁ that is input to the surface of the microlens when the chief ray incident angle is 0 ° and the energy E ₂ that reaches the light receiving element under a predetermined condition. represented by E _1. For input light, as shown in FIG. 8, the OBJECT surface on ZEMAX is set in contact with the microlens surface (the first layer on ZEMAX). Considering this as a light source with uniform brightness (when the microlens is 2 μm × 2 μm □, a circle with a radius of √2 μm circumscribing it), the angle of the ray from the OBJECT plane is 0 ° to the camera lens Random in the range from the F value to the expected angle, and randomly generating rays from the entire surface of the OBJECT plane (however, the processing of rays around the OBJECT plane goes out of the system as shown in FIG. 8a) Light rays are not considered). The parameters of each layer on ZEMAX are shown in Table 1 below.

  Further, the above formulas (3) and (4) are applied to the laminated structure shown in FIG. 3, and the center position of each microlens 12 and each color filter 10 (red filter 10R, green filter 10G, blue filter 10B). As shown in FIG. 9, the shift amount when shifting the center position of is calculated. FIG. 9 is a diagram showing a state in which the principal ray incident on the center position of the microlens reaches the light receiving element at an incident angle of 20 °, as in FIG. 6, and the center position of each microlens 12 and each color. The center position of the filter 10 (red filter 10R, green filter 10G, blue filter 10B) is shifted based on the assumed shift amount obtained from the above equation (3). Further, the upper planarization layer 11, the lower planarization layer 9, the passivation layer 8, and the insulating layer 7a that are substantially continuous between adjacent pixels are also shifted based on the assumed shift amount obtained from the above equation (3). It is regarded as In this case, the entrance center position of each waveguide 15 is not shifted, and the principal ray optical path is assumed to be an optical path passing through the entrance center of the waveguide 15. Under such an assumption, the chief ray is not collected at the center of the light receiving element 3, but even if the optical path is off the center of the light receiving element 3, the waveguide 15 functions and is guided to any part of the light receiving element 3. It is burned. The shift amount is calculated by multiplying the same amount of aberration correction coefficient a in common with the assumed shift amount obtained in each layer. By changing the value of the aberration correction coefficient a, the shift amount of each microlens 12 is changed. Various shift amounts are obtained for the center position and the center position of each color filter 10. Then, shifting is performed based on the calculated shift amount, and the energy at which the light beam incident on the microlens 12 from the camera lens having the F value = 2.8 under the condition of the chief ray incident angle of 30 ° reaches the light receiving element 3 is obtained. The value obtained by the optical simulation as described above for the relative ratio to the input energy is shown in FIG. 10 as the energy hit rate. As shown in FIG. 10, when the value of the aberration correction coefficient a is in the range of 59% to 134%, it is possible to maintain 95% or more of the maximum energy hit rate, and the value of the aberration correction coefficient a is 75% to 119. In the range of%, 99% or more of the maximum energy hit rate can be maintained. From this result, the shift amount (S1 actual) of the center position of each microlens 12 and the shift amount (S3 actual) of the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) The aberration correction coefficient a obtained from the equations (3) and (4) is 0.59 ≦ a ≦ 1.34. In addition, the value of a used for calculation of each shift amount (S1 actual, S3 actual) may be in the above range, and it is not necessary to use the same value common to all the layers to be shifted.

  Furthermore, the above formulas (3) and (4) are applied to the laminated structure shown in FIG. 3 to calculate the shift amount when the center position of each microlens 12 is shifted as shown in FIG. FIG. 11 is a diagram showing a state in which the chief ray incident on the center position of the microlens reaches the light receiving element at an incident angle of 20 °, as in FIG. The shift is performed based on the assumed shift amount obtained from Equation (3). Further, the upper planarization layer 11 that is substantially continuous between adjacent pixels is also considered to have been shifted based on the assumed shift amount obtained from the above equation (3). In this case, the center position of each color filter 10 and the entrance center position of each waveguide 15 are not shifted, and the principal ray optical path is assumed to be an optical path passing through the entrance center of the waveguide 15. Under such an assumption, the chief ray is not collected at the center of the light receiving element 3, but even if the optical path is off the center of the light receiving element 3, the waveguide 15 functions and is guided to any part of the light receiving element 3. It is burned. The shift amount is calculated by multiplying the same amount of aberration correction coefficient a in common with the assumed shift amount obtained in each layer. By changing the value of the aberration correction coefficient a, the shift amount of each microlens 12 is changed. Various shift amounts are obtained only for the center position. Then, shifting is performed based on the calculated shift amount, and the energy at which the light beam incident on the microlens 12 from the camera lens having the F value = 2.8 under the condition of the chief ray incident angle of 30 ° reaches the light receiving element 3 is obtained. The value obtained by optical simulation as described above for the relative ratio to the input energy is shown in FIG. 12 as the energy hit rate. As shown in FIG. 12, the energy hit rate is improved as compared to a = 1 (100%) when the value of the aberration correction coefficient a is in the range of 35% to 100%. Further, it is possible to maintain 95% or more of the maximum energy hit rate when the value of the aberration correction coefficient a is in the range of 46% to 81%, and maximum when the value of the aberration correction coefficient a is within the range of 55% to 72%. 99% or more of the energy hit rate can be maintained. From this result, the aberration correction coefficient a when obtaining the shift amount (S1 actual) of the center position of each microlens 12 from the above equations (3) and (4) is 0.46 ≦ a ≦ 0.81. Become.

The solid-state imaging device of the present invention as described above has a microlens, a color filter, and a waveguide assuming an optical path from the principal ray incident on the center position of each microlens from the center of the exit pupil of the camera lens to the center of the light receiving device. Since the shift amount is set by multiplying the assumed shift amount by the aberration correction coefficient a in consideration of the coma aberration of the microlens that is not taken into consideration in the conventional solid-state imaging device in which the shift is shifted, the peripheral portion of the effective imaging region The shading is effectively suppressed.
The above-described embodiment of the solid-state imaging device is an exemplification, and the present invention is not limited to this embodiment.

[Method for Manufacturing Solid-State Imaging Device]
Next, the manufacturing method of the solid-state imaging device of the present invention will be described using the above-described solid-state imaging device 1 as an example.
As described above, the solid-state imaging device 1 having the waveguide 15 is totally reflected even when obliquely incident light is incident on the side wall of the waveguide 15, so that the condensing center of the microlens is slightly shifted from the center of the light receiving device 3. However, the structure is less likely to cause problems. That is, as shown in the above-described examination result of the present invention, a certain amount of width is allowed for the shift amount. In the present invention, from this viewpoint, even when a camera lens having a non-linear relationship between the image height and the chief ray incident angle as shown in FIG. It was investigated. A camera lens having a non-linear characteristic as shown in FIG. 13 is an aspherical lens that has been adopted in recent years in order to make the camera smaller and thinner. However, in such a camera lens, in a linear shift that has been conventionally performed, for example, when a microlens is shifted, in a shift that performs micro scaling such as a reduction ratio of 99.99% on a photomask for a microlens, It is difficult to shift a microlens suitable for nonlinear camera lens characteristics. In other words, in contrast to a linear shift that scales at a fixed reduction ratio, a non-linear shift cannot use a fixed reduction ratio, and the arrangement pitch that changes slightly according to the pixel position is designed over all pixels. Since it is necessary to redo, the design man-hour becomes enormous. In addition, since the amount of change in the arrangement pitch between adjacent pixels is extremely small, the dimensional change required for the photomask data is often less than 1 nm, which is the minimum dimensional unit for photomask creation. This causes a problem that the slight change amount cannot be expressed on the photomask.

In the manufacturing method of the present invention, the center position of each microlens 12, the center position of each color filter 10, the opening center position of each light shielding layer 6, and the center position of the entrance of each waveguide 15 are determined. Rather, it is shifted by a predetermined shift amount toward the center of the effective imaging area. Then, the shift amount is set as follows.
That is, the principal ray that has entered the center position of each microlens 12 from the center of the exit pupil of the camera lens is incident on the microlens 12 and each material on the optical path from the microlens 12 to the light receiving element 3. It is assumed that at each boundary of the layer, an optical path that refracts corresponding to the difference in refractive index of the material on both sides of the boundary and reaches the center of the light receiving element 3 is taken. The assumed shift amount obtained from the difference between the position on the optical path of the light beam obtained from this assumption and the position corresponding to the center of the light receiving element 3 is multiplied by the value obtained by multiplying the aberration correction coefficient a1 by the aberration correction coefficient a2. Find the value. Next, a curve formed by a value obtained by multiplying the aberration correction coefficient a1 on a graph in which these two kinds of values for each pixel are plotted on the Y axis and the number of pixels with the center of the effective imaging area being zero is plotted on the X axis. And the amount of shift are set so as to be on an arbitrary straight line in a region sandwiched by curves obtained by multiplying the value obtained by multiplying the aberration correction coefficient a2.

First, the assumed shift amount will be described with reference to FIG. As shown in FIG. 2, the microlens 12, the upper planarizing layer 11, the color filter 10, the lower planarizing layer 9, the passivation layer 8, the insulating layer 7a, the waveguide 15, and the light receiving element 3 are arranged in this order from the light incident side. It is installed. Then, the microlens 12 positioned closest to the light incident side is the first layer, and as described above, the material on both sides of the boundary at each boundary of each material layer on the optical path from the microlens 12 to the light receiving element 3. The i-th layer when shifting from the first layer to the N-th layer (1 ≦ N ≦ M) The assumed shift amount Si for i = 1, 2,..., N) is obtained from the following equation (5). This equation (5) is derived in the same manner as the above equation (1).
Si = Σ _{j = i} ^M d _j tan θ _j (5)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = ray angle of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.

In the illustrated example, M = N = 7, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁷ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁷ d _j tan θ _j . Further, the assumed shift amount S7 of the waveguide 15 with i = 7 is S7 = d ₇ tan θ ₇ . Here, as in FIG. 1, if the microlens side surface of the opening of the light shielding layer 6 exists in the same plane as the entrance of the waveguide 15, the opening center position of the light shielding layer 6 and the entrance center position of the waveguide 15 are located. The assumed shift amount is an assumed shift amount S7 obtained when i = 7. The waveguide 15 has a high refractive index material portion and a low refractive index material portion, but the region through which the principal ray passes is a high refractive index material portion. Consider the rate. On the other hand, when the microlens side surface of the opening of the light shielding layer 6 is not flush with the entrance of the waveguide 15, the following occurs. First, the shift of the opening of the light shielding layer 6 when the surface of the opening of the light shielding layer 6 is closer to the microlens than the entrance of the waveguide 15 is shown in FIG. The above formula (5) may be assembled in consideration of a configuration with one layer added. In the example of FIG. 20, M = N = 8, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁸ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁸ d _j tan θ _j . Further, the assumed shift amount S7 of the light shielding layer 6 with i = 7 is S7 = Σ _{j = 7} ⁸ d _j tan θ _j . Further, the assumed shift amount S8 of the waveguide 15 with i = 8 is S8 = d ₈ tan θ ₈ . Next, the shift of the opening of the light shielding layer 6 when the microlens side surface of the opening of the light shielding layer 6 is on the light receiving element side from the entrance of the waveguide 15 is as shown in FIG. 21, for example. That is, M = N = 9, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁹ d _j tan θ _j . Further, assume the shift amount S3 of the color filter 10 of i = 3 becomes ^{_{S3 = Σ j = 3 9 d}} j tanθ j. Further, assume the shift amount S7 in waveguide 15 i = 7 (inlet) becomes ^{_{S7 = Σ j = 7 9 d}} j tanθ j. Furthermore, the assumed shift amount S8 of the light shielding layer 6 with i = 8 is S8 = Σ _{j = 8} ⁹ d _j tan θ _j . At this time, the waveguide 15 extends over three layers of i = 7 to 9, but is substantially continuous. Further, in the shift of the entrance portion of the waveguide 15 and the light shielding layer 6, the refractive index of the high refractive index material portion of the waveguide 15 may be taken into consideration.

Further, in the manufacturing method of the present invention, the center position of each microlens 12 and the center position of each color filter 10 are shifted by a predetermined shift amount from the center of the corresponding light receiving element 3 toward the center of the effective imaging region. It is something to be made. Then, the shift amount is set as follows.
That is, the principal ray that has entered the center position of each microlens 12 from the center of the exit pupil of the camera lens is incident on the microlens 12 and each material on the optical path from the microlens 12 to the light receiving element 3. It is assumed that at each boundary of the layer, an optical path is taken that reaches the center of the entrance of the waveguide 15 by being refracted corresponding to the difference in refractive index between the materials on both sides of the boundary. The assumed shift amount obtained from the difference between the position on the optical path of the light beam obtained from this assumption and the position corresponding to the center of the light receiving element 3 is multiplied by the value obtained by multiplying the aberration correction coefficient a1 by the aberration correction coefficient a2. Find the value. Next, a curve formed by a value obtained by multiplying the aberration correction coefficient a1 on a graph in which these two kinds of values for each pixel are plotted on the Y axis and the number of pixels with the center of the effective imaging area being zero is plotted on the X axis. And the amount of shift are set so as to be on an arbitrary straight line in a region sandwiched by curves obtained by multiplying the value obtained by multiplying the aberration correction coefficient a2.

First, the assumed shift amount will be described with reference to FIG. As shown in FIG. 9, the microlens 12, the upper planarizing layer 11, the color filter 10, the lower planarizing layer 9, the passivation layer 8, the insulating layer 7 a, the waveguide 15, and the light receiving element 3 are arranged in this order from the light incident side. It is installed. Then, the microlens 12 positioned closest to the light incident side is the first layer, and as described above, the material on both sides of the boundary at each boundary of each material layer on the optical path from the microlens 12 to the light receiving element 3. It is assumed that an optical path that is refracted corresponding to the difference in refractive index and reaches the center of the entrance of the waveguide 15 is assumed, and the laminated structure located on the light incident side from the light receiving element is an M layer structure, and is located most on the light incident side. When the microlens positioned is the first layer and the waveguide entrance is the M ′ layer (M ′ ≦ M), when shifting from the first layer to the N layer (1 ≦ N <M ′) The assumed shift amount Si of the i-th layer (i = 1, 2,..., N) is obtained from the following equation (6). This equation (6) is derived in the same manner as the above equation (3).
Si = Σ _{j = i} ^M′−1 d _j tan θ _j (6)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M′-1-th layer,
θ _j = ray angle of the j-th layer located between the i-th layer and the M′−1-th layer
And
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.

In the illustrated example, M = M ′ = 7, N = 6, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁶ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁶ d _j tan θ _j .
At this time, if the microlens side surface of the opening of the light shielding layer 6 is in the same plane as the entrance of the waveguide 15, or is located on the light receiving element 3 side from the same plane, the opening of the light shielding layer 6 is shifted. Not. On the other hand, when the microlens side surface of the opening of the light shielding layer 6 is on the microlens side from the entrance of the waveguide 15, for example, as shown in FIG. And what is necessary is just to assemble said Formula (6). In the number of layers in FIG. 20, M = M ′ = 8 and N = 7, and the assumed shift amount S1 of the microlens 12 with i = 1 is S1 = Σ _{j = 1} ⁷ d _j tan θ _j . Further, the assumed shift amount S3 of the color filter 10 with i = 3 is S3 = Σ _{j = 3} ⁷ d _j tan θ _j . The assumed shift amount S7 of the light shielding layer 6 with i = 7 is S7 = d ₇ tan θ ₇ .

Next, the aberration correction coefficient a1 and the aberration correction coefficient a2 will be described.
First, when setting the shift amount of the center position of each micro lens 12, the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B) and the entrance center position of each waveguide 15, an aberration correction coefficient is set. a1 and the aberration correction coefficient a2 are in the range of 0.39 to 1.26, and a1 <a2. That is, based on the shift amounts obtained by multiplying the assumed shift amount calculated from the above equation (5) by various aberration correction coefficients a, the center position of each microlens 12, the center position of each color filter 10, and each guide. The center position of the entrance of the waveguide is shifted, and the energy at which the light beam incident on the microlens 12 from the camera lens having an F value = 2.8 reaches the light receiving element 3 under the condition of the principal ray incident angle of 30 ° is obtained. When the value obtained by the optical simulation as described above is calculated as the energy hit rate, the curve as shown in FIG. 7 is obtained. Then, as shown in FIG. 7, when the value of the aberration correction coefficient a is in the range of 39% to 126%, an energy hit ratio of 95% or more of the maximum energy hit ratio when the value of the aberration correction coefficient a is changed. Can be maintained. Here, for example, even when the relationship between the image height and the chief ray incident angle is non-linear as shown in FIG. 13, the value of the aberration correction coefficient a is constant in the range of 39% to 126%. Therefore, it is not necessary to change the shift amount non-linearly. Therefore, within the above range (0.39 to 1.26), for example, the aberration correction coefficient a1 is set to 0.50, the aberration correction coefficient a2 is set to 1.1, and these two values for each pixel are set. When the number of pixels in which the center of the effective imaging area is 0 is plotted on the Y axis, the curve A formed by multiplying the aberration correction coefficient a1 and the aberration correction coefficient a2 are multiplied as shown in FIG. A region sandwiched between curves B formed by values is obtained. Then, a linear shift can be performed so as to ride on an arbitrary straight line in a region sandwiched between the curves A and B. Here, an arbitrary straight line in the region sandwiched between the curve A and the curve B is sandwiched between the curve A and the curve B from the center of the effective imaging region to the outermost peripheral pixel (the 1246th pixel in the illustrated example). A straight line that does not deviate from the region. Therefore, in FIG. 14, a straight line L1 that is in contact with the curve A near the origin (the center of the effective imaging area) and a straight line L2 that connects the point on the curve B and the origin (the center of the effective imaging area) at the 1246th pixel. It is an arbitrary straight line within the enclosed area (hatched). Although the description of the shift of the light shielding layer 6 is omitted here, the assumed shift amount described in the description of the solid-state imaging device is also calculated for the light shielding layer 6, and the aberration correction coefficient a1 having the same value as the above is calculated. Using the aberration correction coefficient a2, the shift amount of the opening center portion of the light shielding layer 6 can be obtained by the same procedure.

  In the example of FIG. 14, the outermost peripheral pixel in the major axis direction of the effective imaging region is the 1246th pixel from the center, but using the same camera lens and the same pixel pitch, the number of pixels is, for example, When the effective imaging area has 1000 pixels in the major axis direction, linear shift is performed so as to ride on a straight line located in an area between the curve A and the curve B in the section from 0 pixel to 1000 pixels in the graph of FIG. be able to. In this case, the lower boundary line L1 in the hatched area in FIG. 14 is the same, but the upper boundary line L2 is expanded as shown by a one-dot chain line in FIG.

  Next, when setting the shift amount between the center position of each microlens 12 and the center position of each color filter 10 (red filter 10R, green filter 10G, blue filter 10B), the aberration correction coefficient a1 and the aberration correction coefficient a2 are: The range is 0.59 to 1.34, and a1 <a2. That is, the center position of each microlens 12 and the center position of each color filter 10 are shifted based on shift amounts obtained by multiplying the assumed shift amount calculated from the above equation (6) by various aberration correction coefficients a. The energy at which the light beam incident on the microlens 12 from the camera lens having an F value = 2.8 under the principal ray incident angle of 30 ° reaches the light receiving element 3 is obtained, and the relative ratio to the input energy is determined as described above. When the value obtained by the optical simulation is calculated as the energy hit rate, the curve as shown in FIG. 10 is obtained. Then, as shown in FIG. 10, when the value of the aberration correction coefficient a is in the range of 59% to 134%, the energy hit ratio of 95% or more of the maximum energy hit ratio when the value of the aberration correction coefficient a is changed. Since it can be maintained and a certain shading correction effect is achieved, there is no need to change the shift amount nonlinearly. Therefore, within the above range (0.59 to 1.34), for example, the aberration correction coefficient a1 is set to 0.6, the aberration correction coefficient a2 is set to 1.3, and these two values for each pixel are set. When the number of pixels in which the center of the effective imaging area is 0 is plotted on the Y axis, the curve A formed by multiplying the aberration correction coefficient a1 and the aberration correction coefficient a2 are multiplied as shown in FIG. A region sandwiched between curves B formed by values is obtained. Then, a linear shift is performed so as to ride on a straight line located in a region sandwiched between the curves A and B (an arbitrary straight line in a region surrounded by two straight lines L1 and L2 and hatched in FIG. 15). It can be carried out.

  Such a method for manufacturing a solid-state imaging device according to the present invention allows the shift amounts of the microlens and the color filter to be used in an effective imaging area even when a camera lens having a nonlinear relationship between the image height and the chief ray incident angle is used. There is no need to change nonlinearly from the center to the periphery. Therefore, it is possible to easily manufacture a solid-state imaging device in which shading around the effective imaging region is effectively suppressed. Of course, the method for manufacturing a solid-state imaging device of the present invention is also effective when the camera lens characteristic is a linear image height / chief ray incident angle. For example, even when linear shift is performed, assuming that the microlens reduction ratio obtained from the shift amount is 99.978%, the pixel pitch after multiplying the pixel pitch of 2 μm by the reduction ratio is 1.99956 μm. At this time, if a quintuple photomask is used for microlens formation, the pitch on the photomask is 9.9978 μm, and a fraction less than the minimum grid (1 nm) at the time of electron beam drawing of the photomask occurs. If this can be rounded to 9.998 μm (that is, the reduction ratio is 99.98%), the drawing data for the microlens photomask can be easily created. In this example, the shift amount per pixel on the pentaploid photomask is changed from 2.2 nm to 2 nm, but there is no problem if the change is within the range of the aberration correction coefficients a1 and a2. It becomes.

Here, an example of a manufacturing method in the case of shifting the waveguide will be described with reference to FIGS.
First, a plurality of light receiving elements 3 are two-dimensionally arranged on the substrate 2 at a constant arrangement pitch, and further, an insulating layer 7 having wiring layers 4 and 5 and a light shielding layer 6 is formed (FIG. 16A). ).
Next, a positive photosensitive resist layer 41 is formed on the surface of the insulating layer 7 (FIG. 16B), and the photosensitivity is obtained through a photomask provided with gradation with a dot pattern having a resolution equal to or lower than the resolution of the exposure wavelength. The resist layer 41 is exposed and developed (resist removal of the exposed portion) to form a cutout portion 42 (FIG. 16C). At this time, in the right view of FIG. 16C, the right edge of the punched portion 42 is substantially vertical, but the left edge has an inclination. The photomask pattern corresponding to the right edge has no gradation and forms substantially vertical edges as two gradations (a normal white and black pattern) of a light shielding part and a non-light shielding part. In contrast, the photomask pattern corresponding to the left edge is provided with a region having gradation corresponding to the width of the inclined portion, and the density of the dot pattern is changed stepwise or substantially continuously within the gradation region. If a pattern is used, an edge having an inclination can be formed.

  Next, the insulating layer 7 is anisotropically dry-etched using the resist layer 41 having the cutouts 42 as a mask, and a hole 43 for forming a waveguide is formed (FIG. 17A). Next, a high refractive index material such as silicon nitride is formed on the insulating layer 7 by CVD or the like to form a high refractive index material layer 15 '(FIG. 17B). Thereafter, the surface irregularities of the high refractive index material layer 15 ′ are planarized by CMP (Chemical Mechanical Polish), thereby forming the waveguide 15 (FIG. 17C).

[Imaging device]
FIG. 18 is a schematic cross-sectional view showing an embodiment of the imaging apparatus of the present invention. In FIG. 18, the imaging device 21 of the present invention includes a substrate 23 provided with the solid-state imaging device 22 of the present invention, a sealing member 24 disposed outside the solid-state imaging device 22, and the sealing member 24. And a transparent protective material 25 disposed to face the solid-state imaging element 22 with a desired gap. The solid-state image sensor 22 is connected to an external terminal 28 via a wiring 26 and front and back conductive vias 27. Such a ceramic package type imaging device 21 can be used for various digital cameras, video cameras, and the like, and the sensitivity, size, and thickness of the camera can be reduced.

FIG. 19 is a schematic cross-sectional view showing another embodiment of the imaging apparatus of the present invention. An imaging device 31 of the present invention shown in FIG. 19 is an example of a mobile phone camera module, and includes a substrate 33 provided with the solid-state image sensor 32 of the present invention and a sealing member disposed outside the solid-state image sensor 32. 34, an infrared cut filter 35 disposed so as to face the solid-state imaging device 32 with a desired gap, a lens barrel 36 disposed on the infrared cut filter 35, and the inside of the lens barrel 36 The lens unit 37 attached to the is provided. Such an image pickup apparatus 31 can be reduced in size and thickness because the solid-state image pickup device 32 of the present invention is subjected to shading correction and has high sensitivity.
The image pickup apparatus of the present invention is not limited to the above-described embodiment, and any structure that includes the solid-state image pickup element of the present invention as a solid-state image pickup element may be used, and the configurations of various conventional image pickup apparatuses may be employed as they are. it can.

Next, an Example is shown and this invention is demonstrated further in detail.
[Example 1]
First, the pixel light receiving unit pitch is 2.0 μm, and the number of pixels is 2592 (X-axis direction) × 1944 (Y-axis direction) photodiodes (light receiving unit size 1.0 μm × 1.0 μm), which are shown in FIG. As described above, a plurality of light receiving elements 3 two-dimensionally arranged on the substrate 2 at a constant arrangement pitch, an insulating layer 7 (silicon oxide) having wiring layers 4 and 5 made of Al, and a light shielding layer 6, and a passivation layer 8 ( A wafer on which a CMOS sensor provided with silicon nitride) and a waveguide 15 (silicon nitride) was formed was prepared. In this CMOS sensor, the thickness of the passivation layer is 0.3 μm, the thickness of the insulating layer interposed between the passivation layer and the waveguide is 0.3 μm, the thickness of the waveguide is 2.1 μm, and the opening center of the light shielding layer is And the entrance center of the waveguide are shifted based on a shift amount (S7 actual) described later. The entrance plane dimension of the waveguide was 1.5 μm × 1.5 μm, and the exit plane dimension was 1.0 μm × 1.0 μm, similar to the photodiode dimension. Further, as a result of measuring the refractive index of the passivation layer, the insulating layer, and the waveguide with a spectroscopic ellipsometer, the refractive index of the passivation layer is 2.0, the refractive index of the insulating layer is 1.46, and the refractive index of the waveguide is 1.88. The refractive index of the insulating layer outside the waveguide was 1.46. In addition, the value of the refractive index is a value at a wavelength of 550 nm, unless otherwise specified, including the following.

(Formation of lower planarization layer)
A photo-curing acrylic transparent resin material (CT-2020L manufactured by Fuji Microelectronics Materials Co., Ltd.) is spin-coated on the passivation layer, followed by pre-baking, UV exposure, and post-baking to form a lower planarizing layer ( A thickness of 0.3 μm) was formed. As a result of measuring the refractive index of the lower planarizing layer in the same manner as described above, it was 1.56.

(Formation of color filter)
The following materials were prepared as negative photosensitive red materials (R materials), green materials (G materials), and blue materials (B materials).
Material for R: SR-4000L manufactured by Fuji Microelectronic Materials Co., Ltd.
Material for G: SG-4000L manufactured by Fuji Microelectronic Materials Co., Ltd.
Material for B: SB-4000L manufactured by Fuji Microelectronic Materials Co., Ltd.

The above materials are spin-coated in the G, R, and B formation order, pre-baked, exposed with a 1/5 reduction type i-line stepper, developed, and post-baked to form a color filter (film thickness 0.8 μm) did. That is, first, a G material was applied onto the lower planarizing layer, exposed and developed, and then post-baked (220 ° C., 10 minutes) to form a green filter in a checkered pattern. Next, an R material was applied so as to cover the green filter, exposed and developed using a photomask, and then post-baked (220 ° C., 10 minutes) to form a red filter. Next, the B material was applied so as to cover the red filter and the green filter, and after exposure and development using a photomask, post baking (220 ° C., 10 minutes) was performed to form a blue filter.
The photomask used in the above exposure was a color filter pattern shifted based on a shift amount (S3 actual) described later.
As a developer, a 50% dilution of CD-2000 manufactured by Fuji Microelectronic Materials Co., Ltd. was used.
As a result of measuring the refractive index of each color filter of the formed color filter in the same manner as described above, the refractive index of the red filter is 1.59 (wavelength 620 nm), the refractive index of the green filter is 1.60 (wavelength 550 nm), and the blue filter The refractive index was 1.61 (wavelength 450 nm).

(Formation of upper planarization layer)
A photocurable acrylic transparent resin material (CT-2020L manufactured by Fuji Microelectronics Materials Co., Ltd.) is spin-coated on the color filter, followed by pre-baking, UV exposure, and post-baking to form an upper planarizing layer. Formed. The formed flattened layer had a thickness of 0.3 μm, and the refractive index measured in the same manner as described above was 1.56.

(Formation of microlenses)
MFR401L made by JSR Co., Ltd. as a microlens material is spin-coated on the upper planarizing layer, and pre-baking, exposure with a 1/5 reduction type i-line stepper, development, post-exposure, and post-baking melt flow are performed. A lens (height 0.675 μm) was formed. As a result of measuring the refractive index of the formed microlens in the same manner as described above, it was 1.61. A 1.19% solution of TMAH (tetramethylammonium hydroxide) was used as the developer.
The photomask used in the above exposure is the above-described gradation photomask, and a microlens pattern shifted based on a shift amount (S1 actual) described later is used.

Next, the bonding pad portion was opened. That is, a positive resist (i-line positive resist PFI-27 manufactured by Sumitomo Chemical Co., Ltd.) is spin-coated, and after pre-baking, exposure and development are performed using a photomask having a pattern corresponding to the bonding pad portion and the scribe portion. went. As a result, a resist pattern having openings in the bonding pad portion and the scribe portion was formed, and oxygen ashing was performed using this resist pattern as a mask, and the planarizing layer on the portion was removed by etching. Next, the positive resist was removed using a resist stripping solution.
Next, the wafer was diced and package assembled to produce the solid-state imaging device of the present invention.

  The solid-state imaging device thus manufactured is combined with a camera lens having the characteristics shown in FIG. The chief ray incident angle is 5 ° at the four corners), and the chief ray incident angle is 5 °, 10 ° when the sensitivity in the effective imaging region (chief ray incident angle 0 °) is 100%. The relative sensitivity of each green pixel at 15 °, 20 °, 25 °, and 30 ° was measured, and the results are shown in Table 2 below. From the results shown in Table 2, it was confirmed that shading was suppressed.

Here, setting of the shift amount (S7 actual) of the opening center of the light shielding layer and the entrance center of the waveguide, the shift amount of the color filter (S3 actual), and the shift amount of the microlens (S1 actual) will be described. In FIG. 2, d ₁ = 0.675 μm, d ₂ = 0.3 μm, d ₃ = 0.8 μm, d ₄ = 0.3 μm, d ₅ = 0.3 μm, d ₆ = 0.3 μm, d ₇ = 2. and .1Myuemu, _{also, n 0 = 1, n 1} = 1.61, n 2 = 1.56, n 3 = 1.60, n 4 = 1.56, n 5 = 2.0, n 6 = 1 .46, n ₇ = 1.88, and refractive index of the insulating layer outside the waveguide = 1.46. The chief ray incident angle θ ₀ is 30 ° at the 1296th pixel in the X-axis direction and the 972 pixel in the Y direction from the center of the effective image pickup region, and the chief ray incident angle θ ₀ is 0 at the center of the effective image pickup region. It was assumed that θ ₀ changes so as to be °.

The assumed shift amount S7 between the opening center of the light shielding layer of i = 7 and the entrance center of the waveguide is that the chief ray incident angle θ ₀ is 0 ° to 30 ° (from the center of the effective imaging region to the outermost peripheral pixel). And equivalent to S7 = Σ _{j = 7} ⁷ d _j tan θ _j = d ₇ tan θ ₇ based on the above formula (5). A value obtained by multiplying S7 calculated in this way by 0.5 as the aberration correction coefficient a is plotted on the XY axes to obtain a curve A as shown in FIG. Further, a value obtained by multiplying S7 calculated from the equation (5) by 1.1 as the aberration correction coefficient a is plotted on the XY axes, and a curve B is obtained as shown in FIG. As an arbitrary straight line between the curves A and B, the shift amount of the outermost peripheral pixel (the 1296th pixel in the X-axis direction and the 972 pixel in the Y-axis direction) is 0.520 μm (X A straight line having an axial direction of 0.416 μm and a Y-axis direction of 0.312 μm was set, and a shift amount (S7 actual) between the opening center of the light shielding layer and the entrance center of the waveguide was set so as to be on this straight line.

Further, the assumed shift amount S3 of the color filter of i = 3 is obtained by changing the chief ray incident angle θ ₀ from 0 ° to 30 ° (corresponding from the center of the effective imaging region to the outermost peripheral pixel). Based on the equation (5), it was calculated from S3 = Σ _{j = 3} ⁷ d _j tan θ _j . A value obtained by multiplying S3 calculated in this way by 0.5 as the aberration correction coefficient a is plotted on the XY axes to obtain a curve A as shown in FIG. Further, a value obtained by multiplying S3 calculated from Expression (5) by 1.1 as the aberration correction coefficient a is plotted on the XY axes, and a curve B is obtained as shown in FIG. As an arbitrary straight line between the curved lines A and B, the shift amount of the outermost peripheral pixel (the 1296th pixel in the X-axis direction and the 972 pixel in the Y-axis direction) is 1.016 μm (X A straight line having an axial direction of 0.813 μm and a Y-axis direction of 0.610 μm was set, and the shift amount (S3 actual) of the color filter was set so as to be on this straight line.

Further, the assumed shift amount S1 of the microlens with i = 1 is obtained by changing the chief ray incident angle θ ₀ from 0 ° to 30 ° (corresponding from the center of the effective imaging region to the outermost peripheral pixel). Based on the equation (1), S1 = Σ _{j = 1} ⁷ d _j tan θ _j was calculated. A value obtained by multiplying S1 calculated in this way by 0.5 as the aberration correction coefficient a based on the above equation (2) is plotted on the XY axes, and a curve A is obtained as shown in FIG. . Further, a value obtained by multiplying S1 calculated from the equation (1) by 1.1 as the aberration correction coefficient a based on the above equation (2) is plotted on the XY axes, and as shown in FIG. B was obtained. As an arbitrary straight line in the region sandwiched between the curves A and B, the shift amount of the outermost peripheral pixel (the 1296th pixel in the X-axis direction and the 972 pixel in the Y-axis direction) is 1.306 μm (X A straight line having an axial direction of 1.045 μm and a Y-axis direction of 0.784 μm was set, and the shift amount (S1 actual) of the microlens was set so as to be on this straight line.

[Example 2]
Example 1 except that the shift amount of the color filter (S3 actual) and the shift amount of the microlens (S1 actual) are set as follows, and the center of the opening of the light shielding layer and the center of the entrance of the waveguide are not shifted. In the same manner as described above, the solid-state imaging device of the present invention was produced.
The solid-state imaging device thus manufactured is combined with a camera lens having the characteristics shown in FIG. 13 at F2.8 (in the combination of this camera lens and the CMOS sensor of this embodiment, near the outermost periphery of the effective imaging region (diagonal direction). The chief ray incident angle is 5 ° at the four corners), and the chief ray incident angle is 5 °, 10 ° when the sensitivity in the effective imaging region (chief ray incident angle 0 °) is 100%. The relative sensitivity of each green pixel at 15 °, 20 °, 25 °, and 30 ° was measured, and the results are shown in Table 2 below. From the results shown in Table 2, it was confirmed that shading was suppressed.

Here, setting of the color filter shift amount (S3 actual) and the micro lens shift amount (S1 actual) will be described. In FIG. 2, d ₁ = 0.675 μm, d ₂ = 0.3 μm, d ₃ = 0.8 μm, d ₄ = 0.3 μm, d ₅ = 0.3 μm, d ₆ = 0.3 μm, d ₇ = 2. and .1Myuemu, _{also, n 0 = 1, n 1} = 1.61, n 2 = 1.56, n 3 = 1.60, n 4 = 1.56, n 5 = 2.0, n 6 = 1 .46, n ₇ = 1.88, and refractive index of the insulating layer outside the waveguide = 1.46. The chief ray incident angle θ ₀ is 30 ° at the 1296th pixel in the X-axis direction and the 972 pixel in the Y direction from the center of the effective image pickup region, and the chief ray incident angle θ ₀ is 0 at the center of the effective image pickup region. It was assumed that θ ₀ changes so as to be °.

Then, the assumed shift amount S3 of the color filter of i = 3 is obtained by changing the principal ray incident angle θ ₀ from 0 ° to 30 ° (corresponding to the pixel from the center to the outermost peripheral portion of the effective imaging region). Based on the equation (6), the calculation was made from S3 = Σ _{j = 3} ⁶ d _j tan θ _j . A value obtained by multiplying S3 calculated in this way by 0.6 as the aberration correction coefficient a is plotted on the XY axes to obtain a curve A as shown in FIG. Further, a value obtained by multiplying S3 calculated from Expression (6) by 1.3 as the aberration correction coefficient a is plotted on the XY axes, and a curve B is obtained as shown in FIG. As an arbitrary straight line between the curved lines A and B, the shift amount of the outermost peripheral pixel (the 1296th pixel in the X axis direction and the 972 pixel in the Y axis direction) is 0.717 μm (X A straight line having an axial direction of 0.574 μm and a Y-axis direction of 0.430 μm was set, and the shift amount (S3 actual) of the color filter was set so as to be on this straight line.

Further, the assumed shift amount S1 of the microlens with i = 1 is obtained by changing the chief ray incident angle θ ₀ from 0 ° to 30 ° (corresponding from the center of the effective imaging region to the outermost peripheral pixel). Based on the equation (6), S1 = Σ _{j = 1} ⁶ d _j tan θ _j was calculated. A value obtained by multiplying S1 calculated in this way by 0.6 as the aberration correction coefficient a is plotted on the XY axes to obtain a curve A as shown in FIG. Further, a value obtained by multiplying S1 calculated from Expression (6) by 1.3 as the aberration correction coefficient a is plotted on the XY axes, and a curve B is obtained as shown in FIG. As an arbitrary straight line between the curves A and B, the shift amount of the outermost peripheral pixel (the 1296th pixel in the X-axis direction and the 972 pixel in the Y-axis direction) is 1.135 μm (X A straight line having an axial direction of 0.908 μm and a Y-axis direction of 0.681 μm was set, and the shift amount (S1 actual) of the microlens was set so as to be on this straight line.

[Example 3]
The solid lens of the present invention is the same as in Example 1 except that the shift amount (S1 actual) of the microlens is set as follows and the center of the opening of the light shielding layer, the center of the entrance of the waveguide, and the color filter are not shifted. An image sensor was produced.
The solid-state imaging device thus manufactured is combined with a camera lens having the characteristics shown in FIG. 13 at F2.8 (in the combination of this camera lens and the CMOS sensor of this embodiment, near the outermost periphery of the effective imaging region (diagonal direction). The chief ray incident angle is 5 ° at the four corners), and the chief ray incident angle is 5 °, 10 ° when the sensitivity in the effective imaging region (chief ray incident angle 0 °) is 100%. The relative sensitivity of each green pixel at 15 °, 20 °, 25 °, and 30 ° was measured, and the results are shown in Table 2 below. From the results shown in Table 2, it was confirmed that shading was suppressed.

Here, the setting of the shift amount (S1 actual) of the microlens will be described. In FIG. 2, d ₁ = 0.675 μm, d ₂ = 0.3 μm, d ₃ = 0.8 μm, d ₄ = 0.3 μm, d ₅ = 0.3 μm, d ₆ = 0.3 μm, d ₇ = 2. and .1Myuemu, _{also, n 0 = 1, n 1} = 1.61, n 2 = 1.56, n 3 = 1.60, n 4 = 1.56, n 5 = 2.0, n 6 = 1 .46, n ₇ = 1.88, and refractive index of the insulating layer outside the waveguide = 1.46. The chief ray incident angle θ ₀ is 30 ° at the 1296th pixel in the X-axis direction and the 972 pixel in the Y direction from the center of the effective image pickup region, and the chief ray incident angle θ ₀ is 0 at the center of the effective image pickup region. It was assumed that θ ₀ changes so as to be °.
Then, the assumed shift amount S1 of the microlens with i = 1 is calculated from S1 = Σ _{j = 1} ⁶ d _j tan θ _j based on the above formula (3), and based on the above formula (4), The shift amount (S1 actual) of the microlens is set by multiplying S1 by 0.6 as the aberration correction coefficient a.

[Comparative Example 1]
A solid-state imaging device was manufactured in the same manner as in Example 1 except that the opening center of the light shielding layer, the entrance center of the waveguide, the microlens, and the color filter were not shifted.
The solid-state imaging device thus manufactured is combined with a camera lens having the characteristics shown in FIG. 13 at F2.8 (in the combination of this camera lens and the CMOS sensor of this embodiment, near the outermost periphery of the effective imaging region (diagonal direction). The chief ray incident angle is 5 ° at the four corners), and the chief ray incident angle is 5 °, 10 ° when the sensitivity in the effective imaging region (chief ray incident angle 0 °) is 100%. The relative sensitivity of each green pixel at 15 °, 20 °, 25 °, and 30 ° was measured, and the results are shown in Table 2 below. From the results shown in Table 2, the shading phenomenon was remarkable as compared with Examples 1 to 3.

[Comparative Example 2]
Except that the shift amount of the color filter is set to the assumed shift amount S3 described in the second embodiment, and the shift amount of the microlens is set to the assumed shift amount S1 described in the second embodiment, and nonlinear shift is performed. In the same manner as in Example 1, a solid-state imaging device was produced.
The solid-state imaging device thus manufactured is combined with a camera lens having the characteristics shown in FIG. 13 at F2.8 (in the combination of this camera lens and the CMOS sensor of this embodiment, near the outermost periphery of the effective imaging region (diagonal direction). The chief ray incident angle is 5 ° at the four corners), and the chief ray incident angle is 5 °, 10 ° when the sensitivity in the effective imaging region (chief ray incident angle 0 °) is 100%. The relative sensitivity of each green pixel at 15 °, 20 °, 25 °, and 30 ° was measured, and the results are shown in Table 2 below.

  From the results shown in Table 2, the shading suppressing effect is almost the same as that of the first embodiment, which is slightly better than that of the second embodiment. From this, it was confirmed that the shading suppression effect of the same degree as that of the non-linear shift is possible in the first embodiment in which the linear shift is performed. Therefore, it is much easier and cheaper than the manufacturing method using the non-linear shift. It was confirmed that the image sensor can be manufactured.

  The present invention can be applied to various fields in which a small and highly reliable solid-state imaging device and imaging device are required.

It is a schematic block diagram which shows one Embodiment of the solid-state image sensor of this invention. It is a figure for demonstrating the optical path until the light ray which injected into the microlens reaches a light receiving element. It is a figure which shows the state which the parallel light which injected into the micro lens with the incident angle of 20 degrees condenses on a light receiving element. 3 is a diagram showing a relative intensity level when a light beam (chief ray incident angle 20 °) incident from a camera lens having an F value = 2.8 is condensed on a light receiving element in a state where the coma aberration shown in FIG. 3 occurs. It is. 3 is a diagram showing a relative intensity level when a light beam (chief ray incident angle of 30 °) incident from a camera lens having an F value = 2.8 is condensed on a light receiving element in a state where the coma aberration shown in FIG. 3 occurs. It is. It is a figure which shows the outline of a layer structure at the time of shifting the center position of each microlens, the center position of each color filter, and the opening center position of each light shielding layer. When the shift shown in FIG. 6 is performed, the energy hit rate (relative value) at which the light beam enters the microlens from the camera lens with F value = 2.8 under the condition of the chief ray incident angle of 30 ° and reaches the light receiving element. ). It is a figure explaining the setting of the incident light in simulation. It is a figure which shows the outline of the layer structure at the time of shifting the center position of each micro lens, and the center position of each color filter. When the shift shown in FIG. 9 is performed, the energy hit rate (relative value) at which the light beam enters the microlens from the camera lens having an F value = 2.8 under the condition of the chief ray incident angle of 30 ° and reaches the light receiving element. ). It is a figure which shows the outline of the layer structure at the time of shifting the center position of each micro lens. When the shift shown in FIG. 11 is performed, the energy hit rate (relative value) at which the light beam enters the microlens from the camera lens with an F value = 2.8 under the condition of the chief ray incident angle of 30 ° and reaches the light receiving element. ). It is a figure which shows the camera lens characteristic from which the relationship between an image height and a chief ray incident angle becomes nonlinear. It is a figure for demonstrating the setting of the shift amount of a linear shift with the manufacturing method of this invention. It is a figure for demonstrating the setting of the shift amount of a linear shift with the manufacturing method of this invention. It is process drawing for demonstrating an example of the manufacturing method in the case of waveguide shift. It is process drawing for demonstrating an example of the manufacturing method in the case of waveguide shift. It is a figure for demonstrating an example of the imaging device of this invention. It is a figure for demonstrating the other example of the imaging device of this invention. It is a figure which shows the outline of the layer structure for demonstrating the case where the light shielding layer is shifted. It is a figure which shows the outline of the layer structure for demonstrating the case where the light shielding layer is shifted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Solid-state image sensor 2 ... Board | substrate 3 ... Light receiving element 4,5 ... Wiring layer 6 ... Light-shielding layer 7, 7a ... Insulating layer 8 ... Passivation layer 9 ... Lower planarization layer 10 ... Color filter 11 ... Upper planarization layer 12 ... Microlens 13 ... Microlens array 15 ... Waveguide 21, 31 ... Imaging device

Claims (9)

A plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to each of the light receiving elements, and a red filter, a green filter, and a blue filter arranged corresponding to each of the light receiving elements At least a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements, and these include a microlens array, a color filter, and a waveguide from the light incident side. In the solid-state imaging device, the microlens is disposed in the order of the light receiving elements, and the microlens has a characteristic of generating coma aberration on the optical axis side of the microlens.
The center position of each microlens, the center position of each color filter, and the center position of the entrance of each waveguide are shifted from the center of the corresponding light receiving element toward the center of the effective imaging region. The boundary at the boundary where the principal ray incident on the center position of each microlens from the center of the exit pupil of the lens enters the microlens and each boundary of each material layer on the optical path from the microlens to the light receiving element The difference between the position on the optical path of the light beam obtained by assuming that it takes an optical path to be refracted corresponding to the difference in refractive index of the material on both sides and reach the center of the light receiving element, and the position corresponding to the center of the light receiving element A solid-state imaging device, which is set by multiplying an assumed shift amount obtained from the above by an aberration correction coefficient a, and the aberration correction coefficient a is in a range of 0.39 ≦ a ≦ 1.26. The laminated structure positioned on the light incident side from the light receiving element is an M layer structure, and when the microlens positioned closest to the light incident side is the first layer, the first layer to the Nth layer (1 ≦ N ≦ M) The assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting up to is expressed by the following equation (1)
Si = Σ _{j = i} ^M d _j tan θ _j (1)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = ray angle of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the incident angle of the chief ray incident on
Set in
The shift amount Si actual of the i-th layer (i = 1, 2,..., N) is expressed by the following equation (2).
Si actual = a × Si (2)
Where a is an aberration correction coefficient,
The solid-state imaging device according to claim 1, wherein A plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to each of the light receiving elements, and a red filter, a green filter, and a blue filter arranged corresponding to each of the light receiving elements At least a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements, and these include a microlens array, a color filter, and a waveguide from the light incident side. In the solid-state imaging device, the microlens is disposed in the order of the light receiving elements, and the microlens has a characteristic of generating coma aberration on the optical axis side of the microlens.
The center position of each microlens, or the center position of each microlens and the center position of each color filter is shifted toward the center of the effective imaging area from the center of the corresponding light receiving element, and the shift amount is At the boundary where the principal ray incident on the center position of each microlens from the center of the exit pupil of the camera lens enters the microlens and each boundary of each material layer on the optical path from the microlens to the light receiving element, A position on the optical path of the light beam that is obtained assuming that it takes an optical path that is refracted corresponding to the difference in refractive index between the materials on both sides of the boundary and reaches the entrance center of the waveguide, and a position that corresponds to the center of the light receiving element Is set by multiplying the assumed shift amount obtained from the difference between the aberration correction coefficient a,
The aberration correction coefficient a is in the range of 0.46 ≦ a ≦ 0.81 when only the center position of each microlens is shifted toward the center of the effective imaging region from the center of the corresponding light receiving element. ,
The aberration correction coefficient a is 0.59 ≦ a ≦ when the center position of each microlens and the center position of each color filter are shifted from the center of the corresponding light receiving element toward the center of the effective imaging region. 1. A solid-state imaging device having a range of 1.34. When the laminated structure located on the light incident side from the light receiving element is an M layer structure, the microlens located closest to the light incident side is the first layer and the waveguide entrance is the M ′ layer (M ′ ≦ M) Furthermore, the assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting from the first layer to the N-th layer (1 ≦ N <M ′) is expressed by the following equation (3 )
Si = Σ _{j = i} ^M′−1 d _j tan θ _j (3)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M′-1-th layer,
θ _j = ray angle of the j-th layer located between the i-th layer and the M′−1-th layer
And
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the incident angle of the chief ray incident on
Set in
The shift amount Si actual of the i-th layer (i = 1, 2,..., N) is expressed by the following equation (4).
Si actual = a × Si (4)
Where a is an aberration correction coefficient,
The solid-state imaging device according to claim 3, wherein A plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to each of the light receiving elements, and a red filter, a green filter, and a blue filter arranged corresponding to each of the light receiving elements At least a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements, and these include a microlens array, a color filter, and a waveguide from the light incident side. In the method for manufacturing a solid-state imaging device, the microlens is disposed in the order of the light receiving elements, and the microlens has a characteristic of generating coma aberration on the optical axis side of the microlens.
The center position of each microlens, the center position of each color filter, and the center position of the entrance of each waveguide are shifted by a predetermined shift amount from the center of the corresponding light receiving element toward the center of the effective imaging area. ,
At the boundary where the principal ray incident on the center position of each microlens from the center of the exit pupil of the camera lens enters the microlens and each boundary of each material layer on the optical path from the microlens to the light receiving element, A position on the optical path of the light beam that is obtained assuming that an optical path is refracted corresponding to the difference in refractive index of the material on both sides of the boundary and reaches the center of the light receiving element, and a position corresponding to the center of the light receiving element A value obtained by multiplying the assumed shift amount obtained from the difference by the aberration correction coefficient a1 and the aberration correction coefficient a2 is obtained, and the two types of values for each pixel are set to the Y axis, and the center of the effective imaging area is set to 0. On the graph in which the number of pixels plotted on the X-axis is plotted, an arbitrary straight line in a region sandwiched between a curve formed by multiplying the aberration correction coefficient a1 and a curve formed by multiplying the aberration correction coefficient a2 is applied. The shift amount as Set,
The method for manufacturing a solid-state imaging device, wherein the aberration correction coefficient a1 and the aberration correction coefficient a2 are in a range of 0.39 to 1.26 and a relationship of a1 <a2. The laminated structure positioned on the light incident side from the light receiving element is an M layer structure, and when the microlens positioned closest to the light incident side is the first layer, the first layer to the Nth layer (1 ≦ N ≦ M) 6. The solid-state imaging according to claim 5, wherein the assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting up to is calculated from the following equation (5). Device manufacturing method.
Si = Σ _{j = i} ^M d _j tan θ _j (5)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = ray angle of the _j -th layer located between the i-th layer and the M-th layer,
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on. A plurality of light receiving elements arranged two-dimensionally, a plurality of waveguides arranged two-dimensionally corresponding to each of the light receiving elements, and a red filter, a green filter, and a blue filter arranged corresponding to each of the light receiving elements At least a microlens array in which a plurality of microlenses are two-dimensionally arranged corresponding to each of the light receiving elements, and these include a microlens array, a color filter, and a waveguide from the light incident side. In the method for manufacturing a solid-state imaging device, the microlens is disposed in the order of the light receiving elements, and the microlens has a characteristic of generating coma aberration on the optical axis side of the microlens.
The center position of each microlens and the center position of each color filter are shifted by a predetermined shift amount toward the center of the effective imaging region from the center of the corresponding light receiving element,
At the boundary where the principal ray incident on the center position of each microlens from the center of the exit pupil of the camera lens enters the microlens and each boundary of each material layer on the optical path from the microlens to the light receiving element, A position on the optical path of the light beam that is obtained assuming that it takes an optical path that is refracted corresponding to the difference in refractive index between the materials on both sides of the boundary and reaches the entrance center of the waveguide, and a position that corresponds to the center of the light receiving element A value obtained by multiplying the assumed shift amount obtained from the difference between the aberration correction coefficient a1 and the aberration correction coefficient a2 is obtained, and the center of the effective imaging area is obtained with the two values for each pixel as the Y axis. On the graph in which the number of pixels set to zero is plotted on the X-axis, an arbitrary straight line in a region sandwiched between a curve formed by multiplying the aberration correction coefficient a1 and a curve formed by multiplying the aberration correction coefficient a2 The amount of shift to get on Set
The method for manufacturing a solid-state imaging device, wherein the aberration correction coefficient a1 and the aberration correction coefficient a2 are in a range of 0.59 to 1.34 and a relationship of a1 <a2. When the laminated structure located on the light incident side from the light receiving element is an M layer structure, the microlens located closest to the light incident side is the first layer and the waveguide entrance is the M ′ layer (M ′ ≦ M) Furthermore, the assumed shift amount Si of the i-th layer (i = 1, 2,..., N) when shifting from the first layer to the N-th layer (1 ≦ N <M ′) is expressed by the following equation (6 The method of manufacturing a solid-state imaging device according to claim 7, wherein
Si = Σ _{j = i} ^M′−1 d _j tan θ _j (6)
However, d _j = the thickness of the _j -th layer located between the i-th layer and the M′-1-th layer,
θ _j = ray angle of the j-th layer located between the i-th layer and the M′−1-th layer
And
θ _j = sin ⁻¹ ((n _j−1 / n _j ) sin θ _j−1 ),
n ₀ = 1.0 (the 0th layer is the atmosphere), n _j is the refractive index of the jth layer,
θ ₀ is the center position of the microlens from the exit pupil center of the camera lens
Is the chief ray incident angle incident on.   An imaging apparatus comprising the solid-state imaging device according to claim 1.

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