JP5360102B2 - Solid-state imaging device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve picture quality in a solid-state imaging apparatus by reducing optical color mixing and/or Mg flare. <P>SOLUTION: A CMOS solid-state imaging apparatus of a backside irradiation type has a pixel region 23 where a plurality of pixels 24 each comprising a photoelectric conversion unit PD and a pixel transistor Tr are arrayed and light shielding films 39 formed on the pixel region 23, wherein each light shielding film 39 is grounded. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a solid-state imaging device and an electronic apparatus such as a camera including the solid-state imaging device.

  In consumer digital video cameras and digital still cameras, there has been a demand for miniaturization of equipment that emphasizes high resolving power and portability to project even the details of subjects. In order to realize these requirements, solid-state imaging devices (image sensors) have been developed to reduce the pixel size while maintaining imaging characteristics. However, in recent years, in addition to continuous demands for high resolution and miniaturization, there has been an increasing demand for improvements in minimum subject illuminance, high-speed imaging, and so on. Expectations for improving overall image quality are increasing.

  As the CMOS solid-state imaging device, a front side irradiation type shown in FIG. 30 and a back side irradiation type shown in FIG. 31 are known. In the front-illuminated solid-state imaging device 111, as shown in the schematic configuration diagram of FIG. 30, a pixel in which a plurality of unit pixels 116 each including a photodiode PD serving as a photoelectric conversion unit and a plurality of pixel transistors are formed on a semiconductor substrate 112. The region 113 is configured. Although the pixel transistor is not illustrated, the gate electrode 114 is shown in FIG. 30 to schematically indicate the presence of the pixel transistor. Each photodiode PD is isolated by an element isolation region 115 by an impurity diffusion layer. A multilayer wiring layer 119 in which a plurality of wirings 118 are arranged via an interlayer insulating film 117 is formed on the surface side of the semiconductor substrate 112 where the pixel transistors are formed. The wiring 118 is formed except for a portion corresponding to the position of the photodiode PD. An on-chip color filter 121 and an on-chip microlens 122 are sequentially formed on the multilayer wiring layer 119 via a planarizing film 120. The on-chip color filter 121 is configured by arranging, for example, red (R), green (G), and blue (B) color filters. In the front-illuminated solid-state imaging device 111, the substrate surface on which the multilayer wiring layer 119 is formed is the light receiving surface 123, and light L is incident from the substrate surface side.

  As shown in the schematic configuration diagram of FIG. 31, the back-illuminated solid-state imaging device 131 is a pixel in which a plurality of unit pixels 116 including a photodiode PD serving as a photoelectric conversion unit and a plurality of pixel transistors are formed on a semiconductor substrate 112. The region 113 is configured. Although not shown, the pixel transistor is formed on the surface side of the substrate. In FIG. 31, the gate electrode 114 is shown to schematically indicate the presence of the pixel transistor. Each photodiode PD is isolated by an element isolation region 115 by an impurity diffusion layer. A multilayer wiring layer 119 in which a plurality of wirings 118 are formed through an interlayer insulating film 117 is formed on the surface side of the semiconductor substrate 112 where the pixel transistors are formed. In the back-illuminated type, the wiring 118 can be formed regardless of the position of the photodiode PD. On the other hand, an insulating layer 128, an on-chip color filter 121, and an on-chip micro lens 122 are sequentially formed on the back surface of the semiconductor substrate 112 facing the photodiode PD. In the back-illuminated solid-state imaging device 131, light L is incident from the back side of the substrate with the back surface of the substrate opposite to the substrate surface on which the multilayer wiring layer and the pixel transistor are formed as the light receiving surface 132. Since the light L is incident on the photodiode PD without being restricted by the multilayer wiring layer 119, the opening of the photodiode PD can be widened, and high sensitivity can be achieved.

  The development team of the present applicants takes advantage of the low power consumption and high speed that the CMOS solid-state imaging device has, and changes the basic structure of the pixel to the back-illuminated type to improve sensitivity, which is an important factor for improving image quality. And succeeded in the development of a back-illuminated CMOS solid-state imaging device with reduced noise. This developed back-illuminated CMOS solid-state imaging device has a pixel size of 1,75 μm square, 5 million effective pixels, and 60 frames / second.

  In the conventional surface irradiation type, the wiring 118 on the substrate surface side where the photodiode PD is formed and the pixel transistor hinder the incident light collected by the on-chip microlens, and there is a problem in downsizing the pixel and changing the incident angle. Had. On the other hand, in the backside illumination type, the amount of light entering the unit pixel is increased without being affected by the wiring 118 or the pixel transistor by irradiating light from the backside where the silicon substrate is inverted. It is possible to suppress a decrease in sensitivity to changes in incident angle.

  Backside illumination type CMOS solid-state imaging devices are disclosed in, for example, Patent Literature 1 to Patent Literature 4 and the like. Further, Patent Document 5 discloses a technique using hafnium oxide (HfO 2) as an antireflection film used in a backside illumination type CMOS solid-state imaging device.

JP 2003-31785 A JP-A-2005-353631 JP 2005-353955 A JP 2005-347707 A JP 2007-258684 A

By the way, in the backside illumination type CMOS solid-state imaging device, it has been found that the following problem is remarkably generated in the condensing structure using only the on-chip microlens 122.
(1) It is extremely difficult to completely suppress optical color mixing to adjacent pixels. Although there is no problem in applications such as surveillance and mobile phones, further reduction of color mixing is required for audio / video (AV) [camcorder, digital still camera, etc.] applications.
(2) A light shielding film is provided around the effective pixel to prevent noise in the peripheral circuit area and determine the optical black level. However, the light condensing state changes around the effective pixel due to the step of the light shielding film. Uniform optical characteristics cannot be realized. That is, as shown in FIG. 29, the light shielding film 126 is formed from the optical black level region (so-called optical black region) 113B outside the effective pixel region 13A to the peripheral circuit portion 125 via the insulating film 127. On top of this, an on-chip color filter 121 and an on-chip microlens 122 are formed. At this time, a difference in height d between the lens surfaces of the on-chip microlens 122 occurs between the peripheral portion of the effective pixel region 113 </ b> A and the inner central portion thereof due to a step due to the presence or absence of the light shielding film 126. The condensing state changes due to the difference d in height, and it becomes darker in the peripheral portion with respect to the brightness in the central portion of the effective pixel region, and uniform optical characteristics cannot be obtained. So-called sensitivity unevenness occurs.
(3) During high-intensity light source photography, reflection and diffracted light reflected by the on-chip microlens 122 and the on-chip color filter 121 are reflected on a seal glass or the like on the package of the solid-state imaging device, and enter the solid-state imaging device again. Uniform color mixing in pixels. Due to this color mixture, Mg-colored streak image defects (hereinafter referred to as Mg flare) are generated radially from a high-intensity light source unique to the back-illuminated solid-state imaging device.

  That is, description will be made using the green pixel 151G and the red pixel 151R in FIG. 28A. The light L incident on the on-chip microlens 122 of the green pixel 151G passes through the green filter 121G and enters the photodiode PD of the green pixel, but the oblique light La is partially reflected by the adjacent red pixel 151R near the pixel boundary. The light enters the photodiode PD. This situation is shown by a simulation of light intensity when light having a wavelength of 550 nm is incident on the two pixels of green and red in FIG. 28B. In FIG. 28B, a region portion A is a portion with high light intensity, a light-colored region portion B is a portion with low light intensity, and a dark-colored region portion (striated portion) C is a portion with almost no light intensity. The fine periodic stripe pattern indicates the progress of the wavefront of light. Now, looking at the light incident on the photodiode PD below the light receiving surface 153, in the region D indicated by a circle near the pixel boundary, weak light is incident on the photodiode PD of the red pixel 151R and is mixed. I understand.

  On the other hand, as shown in FIG. 26, a seal glass 135 is arranged through a space 134 in a window on the incident light side of a package (not shown) in which a backside illumination type CMOS solid-state imaging device 131 is housed. Further, an optical low-pass filter 136 is disposed on the seal glass 135 via a space 134, and an infrared cut filter 137 is disposed thereon via the space 134. Further, a camera lens 138 is disposed above. A part of the incident light L <b> 1 that has passed through the camera lens 138 and entered the solid-state imaging device 131 is reflected at each medium interface of the solid-state imaging device 131. The light is reflected mainly from the lens surface of the on-chip microlens 122 and the silicon surface serving as the light receiving surface. Since the on-chip microlenses 122 are periodically arranged, a diffraction phenomenon occurs. Reflection reflected by the solid-state imaging device 131 and diffracted light L2 are reflected at various angles such as reflection from near perpendicular to far away, and reflected by the seal glass 135, the optical low-pass filter 136, and the infrared cut filter 137. It enters the solid-state imaging device 131 again as the re-incident light L3. In particular, the light diffracted at a large angle is reflected by the seal glass 135 and is incident on the solid-state imaging device 131 again, and this becomes the radial Mg flare 141 (see circle E) shown in FIG. The radial white streaks (white flare) 142 are caused by the diaphragm on the camera lens side, and are also a phenomenon that occurs in the surface irradiation type solid-state imaging device, and are not so uncomfortable. However, the Mg flare 141 unique to the back-illuminated solid-state imaging device is conspicuous with respect to the green color of the back when, for example, taking a picture of a sunlight through a tree.

  The occurrence of the Mg flare 141 is caused by white balance processing in the signal processing process for aligning the spectral characteristics of red (R), green (G), and blue (B). Each pixel is similarly mixed by re-incidence of diffracted light, but the white balance process emphasizes the red (R) and blue (B) signals with a larger gain than green (G). Mg flare is generated.

  In the back-illuminated solid-state imaging device, optical color mixing due to leakage of incident light to adjacent pixels and Mg flare due to reflected light may occur, but in front-illuminated solid-state imaging devices, optical color mixing to adjacent pixels may occur. .

  In view of the above-described points, the present invention provides a solid-state imaging device and an electronic apparatus that improve image quality by reducing optical color mixing and / or reducing Mg flare.

A solid-state imaging device according to the present invention includes a semiconductor substrate, a pixel region in which a plurality of pixels having a photoelectric conversion unit and a pixel transistor formed on the semiconductor substrate are arranged, an element isolation region formed on the semiconductor substrate, A light-shielding film formed in the pixel region on the light-receiving surface side of the semiconductor substrate, an anti-reflection film disposed between the light-shielding film and the light-receiving surface, and an on-state provided on the light-receiving surface side of the semiconductor substrate via the light-shielding film Chip color filter and on-chip microlens, and multi-layer wiring layer formed on the opposite side of the light-receiving surface of the semiconductor substrate through an interlayer insulating film, and the element isolation region is grounded and shielded from light The film penetrates the antireflection film and is connected to the element isolation region at the light receiving surface.

  In the solid-state imaging device of the present invention, since the pixel region has a light shielding film, the light shielding film prevents light that cannot be collected by the on-chip microlens from entering adjacent pixels. In addition, the light shielding film suppresses the incidence of diffracted light on the effective pixel. Further, since the light shielding film is grounded, the potential of the light shielding film is fixed, and no adverse effect is exerted on the photoelectric conversion unit, and noise during darkness is reduced.

An electronic apparatus according to the present invention includes a solid-state imaging device, an optical system that guides incident light to the solid-state imaging device, and a signal processing circuit that processes an output signal of the solid-state imaging device. The solid-state imaging device is the above-described solid-state imaging device of the present invention.

  Since the electronic apparatus of the present invention includes the above-described solid-state imaging device, the solid-state imaging device prevents light that cannot be collected by the on-chip microlens from entering adjacent pixels, and diffracted light to the effective pixels Incident can be prevented. Further, since the light shielding film is grounded, the potential of the light shielding film is fixed, and no adverse effect is exerted on the photoelectric conversion unit, and noise during darkness is reduced.

  According to the solid-state imaging device according to the present invention, since light is suppressed from being incident on adjacent pixels by the light-shielding film in the pixel region, optical color mixing can be reduced. Moreover, since the incidence of diffracted light on the effective pixel is suppressed by this light shielding film, the occurrence of Mg flare can be reduced. Further, since the light shielding film is fixed at the ground potential, noise during darkness can be reduced. Therefore, the image quality can be improved.

  According to the electronic apparatus of the present invention, in a solid-state imaging device, optical color mixing can be reduced, Mg flare can be reduced, and dark noise can be reduced, so that a high-quality image can be obtained.

It is a schematic block diagram which shows an example of the CMOS solid-state imaging device applied to this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 1st Embodiment of this invention. A and B are explanatory views of a state in which optical color mixing to adjacent pixels is reduced according to the embodiment of the present invention. It is explanatory drawing which shows the reflection state of the incident light of embodiment of this invention. It is explanatory drawing which Mg flare of embodiment of this invention reduces. It is a manufacturing process figure (the 1) which shows the manufacturing process of the solid-state imaging device concerning AB 1st Embodiment. C to D are manufacturing process diagrams (part 2) illustrating the manufacturing process of the solid-state imaging device according to the first embodiment. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 2nd Embodiment of this invention. It is a manufacturing process figure (the 1) which shows the manufacturing process of the solid-state imaging device concerning AB 2nd Embodiment. C to D are manufacturing process diagrams (part 2) illustrating a manufacturing process of the solid-state imaging device according to the second embodiment. AC is a top view which shows each example of the opening shape of the light shielding film of this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 3rd Embodiment of this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 4th Embodiment of this invention. It is a top view of the principal part which shows the back irradiation type solid-state imaging device which concerns on 4th Embodiment of this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 5th Embodiment of this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 6th Embodiment of this invention. It is a block diagram of the principal part which shows the back surface irradiation type solid-state imaging device which concerns on 7th Embodiment of this invention. It is a block diagram of the principal part which shows the back surface irradiation type solid-state imaging device which concerns on 8th Embodiment of this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 9th Embodiment of this invention. It is a block diagram of the principal part which shows the back surface irradiation type solid-state imaging device which concerns on 10th Embodiment of this invention. It is a block diagram of the principal part which shows the backside illumination type solid-state imaging device which concerns on 11th Embodiment of this invention. It is a block diagram of the principal part which shows the back irradiation type solid-state imaging device which concerns on 12th Embodiment of this invention. It is a block diagram of the principal part which shows the surface irradiation type solid-state imaging device which concerns on 13th Embodiment of this invention. It is a block diagram of the principal part which shows the surface irradiation type solid-state imaging device concerning 14th Embodiment of this invention. It is a schematic block diagram of the electronic device which concerns on 15th Embodiment of this invention. It is explanatory drawing which shows the reflection state of the incident light in the conventional backside illumination type solid-state imaging device. It is explanatory drawing which shows the state where the Mg flare generate | occur | produces in the conventional backside illumination type solid-state imaging device. A and B are explanatory diagrams showing that optical color mixture occurs in adjacent pixels of a conventional backside illumination type solid-state imaging device. It is explanatory drawing which shows that a difference arises in the lens height of the on-chip microlens of an effective pixel area | region in the conventional backside illumination type solid-state imaging device. It is the schematic which shows the conventional surface irradiation type solid-state imaging device. It is the schematic which shows the conventional backside illumination type solid-state imaging device.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
The description will be given in the following order.
1. 1. Schematic configuration example of CMOS solid-state imaging device First embodiment (example of configuration of solid-state imaging device and example of manufacturing method thereof)
3. Second embodiment (example of configuration of solid-state imaging device and example of manufacturing method thereof)
4). Third embodiment (configuration example of solid-state imaging device)
5. Fourth embodiment (configuration example of solid-state imaging device)
6). Fifth embodiment (configuration example of solid-state imaging device)
7). Sixth Embodiment (Configuration Example of Solid-State Imaging Device)
8). Seventh embodiment (configuration example of solid-state imaging device)
9. Eighth embodiment (configuration example of solid-state imaging device)
10. Ninth Embodiment (Configuration Example of Solid-State Imaging Device)
11. Tenth Embodiment (Configuration Example of Solid-State Imaging Device)
12 Eleventh embodiment (configuration example of solid-state imaging device)
13. Twelfth embodiment (configuration example of solid-state imaging device)
14 13th Embodiment (Configuration Example of Solid-State Imaging Device)
15. Fourteenth embodiment (configuration example of solid-state imaging device)
16. Fifteenth embodiment (configuration example of electronic device)

In the solid-state imaging device according to the embodiment of the present invention, image quality is improved by reducing optical color mixture and / or reducing Mg flare. Prior to the description of the embodiment, a method for reducing Mg flare is described. State.
As a result of the analysis, it was found that the strength of the Mg flare 141 unique to the back-illuminated solid-state imaging device has the following relationship.
Mg flare intensity = incident light intensity × image sensor oblique reflectance × sticker glass reflectivity × image sensor oblique sensitivity.
Therefore, there are mainly three ways to reduce Mg flare. A: The generation of the diffracted light L2 is suppressed by devising the pixel structure. B: An antireflection film is formed on the interface of seal glass or the like. C: The diffracted light L3 that is re-reflected and returned by a seal glass or the like is reduced by devising the pixel structure.

Measure B is not a wafer manufacturing process of the image sensor, but a measure on the package side, so the unit price of the image sensor will rise significantly. This is due to the recent progress in consumer digital video cameras and digital still cameras. This is a major demerit against price reduction.
Measure A is a measure in the wafer manufacturing process of the image sensor, and the unit price increase is relatively small. Measure A is essential in terms of suppressing the source of diffracted light, and there is a merit in improving sensitivity by setting the film formation conditions appropriately, but backside illumination for consumer digital video cameras and digital still cameras There is no reduction effect for optical color mixing which is a problem in the solid-state imaging device.
The measure C is a measure in the wafer manufacturing process of the image sensor as in the measure A, and in the embodiment of the present invention, it is a great merit that there is no increase in unit price. Measure C is effective as a measure against Mg flare by suppressing the oblique sensitivity of the image sensor that can be obtained with a back-illuminated solid-state imaging device, although the amount of diffracted light generated and the seal glass reflectivity do not change. At the same time, it is also effective for optical color mixing, which is a problem in back-illuminated solid-state imaging devices for consumer digital video cameras and digital still cameras. By properly setting the aperture design of the light-shielding film, while maintaining the superiority of optical characteristics (high sensitivity, low shading) expected as an optical back-illuminated solid-state imaging device, it sufficiently suppresses optical chromatic mixing with Mg flare I understood that I could do it.
The embodiment of the backside illumination type solid-state imaging device described below is configured based on measures A and / or measures B and C with respect to Mg flare reduction.

<1. Schematic configuration example of CMOS solid-state imaging device>
FIG. 1 shows a schematic configuration of an example of a CMOS solid-state imaging device applied to each embodiment of the present invention. As shown in FIG. 1, the solid-state imaging device 1 of this example includes a pixel region (a so-called imaging region) in which pixels 2 including a plurality of photoelectric conversion elements are regularly arranged in a semiconductor substrate 11, for example, a silicon substrate. 3 and a peripheral circuit portion. The pixel 2 includes, for example, a photodiode serving as a photoelectric conversion element and a plurality of pixel transistors (so-called MOS transistors). The plurality of pixel transistors can be constituted by three transistors, for example, a transfer transistor, a reset transistor, and an amplification transistor. In addition, a selection transistor may be added to configure the transistor with four transistors. Since the equivalent circuit of the unit pixel is the same as usual, the detailed description is omitted. The pixel 2 can also have a shared pixel structure. This pixel sharing structure is composed of a plurality of photodiodes, a plurality of transfer transistors, one shared floating diffusion, and one other shared pixel transistor.

  The peripheral circuit section includes a vertical drive circuit 4, a column signal processing circuit 5, a horizontal drive circuit 6, an output circuit 7, a control circuit 8, and the like.

  The control circuit 8 receives an input clock and data for instructing an operation mode, and outputs data such as internal information of the solid-state imaging device. That is, the control circuit 8 generates a clock signal and a control signal that serve as a reference for operations of the vertical drive circuit 4, the column signal processing circuit 5, and the horizontal drive circuit 6 based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock. To do. These signals are input to the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, and the like.

  The vertical drive circuit 4 is configured by, for example, a shift register, selects a pixel drive wiring, supplies a pulse for driving the pixel to the selected pixel drive wiring, and drives the pixels in units of rows. In other words, the vertical drive circuit 4 selectively scans each pixel 2 in the pixel region 3 sequentially in the vertical direction in units of rows, and the photoelectric conversion element of each pixel 2 through the vertical signal line 9 according to the amount of light received. A pixel signal based on the generated signal charge is supplied to the column signal processing circuit 5.

  The column signal processing circuit 5 is disposed, for example, for each column of the pixels 2, and performs signal processing such as noise removal on the signal output from the pixels 2 for one row for each pixel column. That is, the column signal processing circuit 5 performs signal processing such as CDS, signal amplification, and AD conversion for removing fixed pattern noise unique to the pixel 2. A horizontal selection switch (not shown) is connected to the horizontal signal line 10 at the output stage of the column signal processing circuit 5.

  The horizontal drive circuit 6 is constituted by, for example, a shift register, and sequentially outputs horizontal scanning pulses to select each of the column signal processing circuits 5 in order, and the pixel signal is output from each of the column signal processing circuits 5 to the horizontal signal line. 10 to output.

  The output circuit 7 performs signal processing and outputs the signals sequentially supplied from each of the column signal processing circuits 5 through the horizontal signal line 10. For example, only buffering may be performed, or black level adjustment, column variation correction, various digital signal processing, and the like may be performed. The input / output terminal 12 exchanges signals with the outside.

<2. First Embodiment>
[Configuration example of solid-state imaging device]
FIG. 2 shows a first embodiment of a solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. The solid-state imaging device 21 according to the first embodiment includes, for example, a pixel region (so-called imaging region) 23 in which a plurality of pixels are arranged on a semiconductor substrate 22 made of silicon, and a periphery that is arranged around the pixel region 23 (not shown). A circuit part is formed and configured. The unit pixel 24 includes a photodiode PD serving as a photoelectric conversion unit and a plurality of pixel transistors Tr. The photodiode PD is formed so as to extend over the entire thickness direction of the semiconductor substrate 22, and in the first conductivity type, in this example, the n-type semiconductor region 25 and the second conductivity type so as to face both the front and back surfaces of the substrate, in this example, p. It is configured as a pn junction type photodiode with the type semiconductor region 26. The p-type semiconductor regions facing both the front and back surfaces of the substrate also serve as hole charge accumulation regions for dark current suppression.

  Each pixel 24 including the photodiode PD and the pixel transistor Tr is separated by an element isolation region 27. The element isolation region 27 is formed of a p-type semiconductor region and is grounded, for example. In the pixel transistor Tr, an n-type source region and drain region (not shown) are formed in a p-type semiconductor well region 28 formed on the surface 22A side of the semiconductor substrate 22, and a gate insulating film is formed on the substrate surface between both regions. The gate electrode 29 is formed. In the figure, a plurality of pixel transistors are representatively represented by one pixel transistor Tr and are schematically represented by a gate electrode 29.

  On the surface 22 </ b> A of the semiconductor substrate 22, a so-called multilayer wiring layer 33 is formed, in which a plurality of layers of wirings 32 are arranged via an interlayer insulating film 31. Since no light is incident on the multilayer wiring layer 33 side, the layout of the wiring 32 can be freely set.

  An insulating layer is formed on the substrate back surface 22B that becomes the light receiving surface 34 of the photodiode PD. This insulating layer is formed of an antireflection film 36 in this example. The antireflection film 36 is formed of a multilayer film having different refractive indexes, and in this example, is formed of a two-layer film of a hafnium oxide (HfO 2) film 38 and a silicon oxide film 37.

  In the present embodiment, a light shielding film 39 is formed at the pixel boundary on the antireflection film 36, that is, at a portion corresponding to the pixel boundary. The light shielding film 39 may be any material that shields light, but a material such as aluminum (Al) or tungsten (W), which has a strong light shielding property and can be precisely processed by fine processing, for example, etching, is used. Or it is preferable to form with the film | membrane of copper (Cu).

  A planarization film 41 is formed on the antireflection film 36 including the light shielding film 39, and an on-chip color filter 42 and an on-chip microlens 43 thereon are sequentially formed on the planarization film 41. The on-chip microlens 43 is formed of an organic material such as resin, for example. The planarization film 41 can be formed of an organic material such as resin, for example. For example, a Bayer color filter is used as the on-chip color filter. The light L is incident from the substrate rear surface 22B side, condensed by the on-chip microlens 43, and received by each photodiode PD.

  According to the back-illuminated solid-state imaging device 21 according to the first embodiment, since the light shielding film 39 is formed at the pixel boundary very close to the light receiving surface 34, the on-chip microlens 43 cannot fully collect the light. Light traveling toward the adjacent pixel is blocked. That is, the light shielding film 39 at the pixel boundary can prevent light from entering adjacent pixels and reduce optical color mixing. Further, even if light is incident on the solid-state imaging device 21 arranged in the package and the partially reflected diffracted light is re-reflected by the seal glass and enters the solid-state imaging device 21, the light shielding film 39 at the pixel boundary is used. The incidence of diffracted light is prevented. By blocking the incidence of this diffracted light, it is possible to reduce Mg flare particularly during high-intensity light source photography.

  The reduction of optical color mixture will be described in detail using a simulation of light intensity when light having a wavelength of 550 nm is incident on two pixels, a green pixel and a red pixel, shown in FIG. FIG. 3A shows a green pixel 24G and a red pixel 24R. When light passes through the on-chip microlens 43 and enters the green pixel 24G, the light L0 that cannot be partially condensed is directed toward the red pixel 24R that is an adjacent pixel, but is shielded and reflected by the light shielding film 39. The That is, the light L0 is prevented from entering the red pixel 24R. This is shown by the light intensity simulation in FIG. 3B. In FIG. 3B, similarly to the above, the region A is a portion having a high light intensity, the light-colored portion B is a portion having a low light intensity, and the dark-colored portion is a portion having almost no light intensity. As can be seen from the simulation of FIG. 3B, the light intensity in the vicinity of the boundary D between the photodiode PD of the red pixel 24R and the green pixel 24G is almost zero. That is, optical color mixing is reduced.

  On the other hand, reduction of Mg flare will be described in detail. FIG. 4 shows a reflection state of incident light in a state where the solid-state imaging device 21 of the first embodiment is housed in a package. Similar to the above, the seal glass 135 is disposed through the space 134 in the window on the incident light side of the package (not shown) in which the back-illuminated solid-state imaging device 21 is accommodated. Further, an optical low-pass filter 136 is disposed on the seal glass 135 via a space 134, and an infrared (IR) cut filter 137 is disposed thereon via the space 134. Further above that, a camera lens 138 is arranged.

  As described above, a part of the incident light L1 that has passed through the camera lens 138 and entered the solid-state imaging device 21 is reflected at each medium interface of the solid-state imaging device 21. The reflected light is reflected by the seal glass 135, the optical low-pass filter 136, and the infrared cut filter 137, and reenters the solid-state imaging device 21 side. In particular, the diffracted light L2 reflected at a large angle is reflected by the seal glass 135 and reenters the solid-state imaging device 21 as re-incident light L3. The incidence of diffracted light on the pixel is blocked, and Mg flare does not occur. As shown in FIG. 4, the diffracted light L3 reflected and re-reflected by the green pixel 24G goes to the adjacent red pixel 24R side through the green filter of the other green pixel 24G, but the light shielding film 39 at the pixel boundary. (Refer to the solid line arrow) and is not incident on the red pixel 24R. For this reason, as shown in FIG. 5, in high-intensity light source photography, Mg flare does not appear in the same place (see circle E) where Mg flare appears in FIG.

  In this embodiment, after the light shielding film 39 is formed, the on-chip color filter 42 and the on-chip microlens 43 are formed through the planarization film 41. Since the on-chip microlens 43 is formed through the planarization film 41, all the lens heights of the on-chip microlens 43 on the pixel region are the same. In particular, the lens height of the on-chip microlens 43 in the effective pixel region is the same, and the step d does not occur between the peripheral portion and the central region in the effective pixel region shown in FIG. Therefore, the same luminance can be obtained over the entire screen, that is, there is no occurrence of sensitivity unevenness, and image quality can be improved.

  As described above, the solid-state imaging device 21 can reduce the optical color mixture and reduce the Mg flare by arranging the light shielding film 39 at the pixel boundary close to the light receiving surface. Sensitivity unevenness does not occur and a high-quality image can be taken.

  Thus, the backside illumination type solid-state imaging device 21 according to the first embodiment can improve the image quality.

[Example of Manufacturing Method of Solid-State Imaging Device of First Embodiment]
6 and 7 show a method for manufacturing the solid-state imaging device 21 according to the first embodiment. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. Reference numerals of the omitted parts refer to FIG.

  First, a photodiode PD corresponding to each pixel separated by an element isolation region 27 by a p-type semiconductor region is formed in a region where a pixel region of a silicon semiconductor substrate 22, for example, is to be formed. The photodiode PD has a pn junction composed of an n-type semiconductor region 25 extending over the entire substrate thickness direction and a p-type semiconductor region 26 in contact with the n-type semiconductor region 25 and facing the front and back surfaces 22A and 22B of the substrate. Formed. In a region corresponding to each pixel on the substrate surface 22A, a p-type semiconductor well region 28 in contact with the element isolation region 27 is formed, and a plurality of pixel transistors Tr are formed in the p-type semiconductor well region 28. Each pixel transistor Tr is formed by a source region and a drain region, a gate insulating film, and a gate electrode 29. Furthermore, a multilayer wiring layer 33 in which a plurality of layers of wirings 32 are arranged via an interlayer insulating film 31 is formed on the substrate surface 22A.

Next, as shown in FIG. 6A, an insulating film, in this example, an antireflection film 36 is formed on the substrate back surface 22 </ b> B serving as a light receiving surface, and a light shielding film material layer 39 </ b> A is formed on the antireflection film 36. The antireflection film 36 is formed of a plurality of films having different refractive indexes. In this example, the antireflection film 36 is formed of a two-layer film in which a silicon oxide (SiO ₂ ) film 37 and a hafnium oxide (HfO ₂ ) film 38 are stacked from the substrate back surface 22B side. . Each of the silicon oxide film 37 and the hafnium oxide film 38 is formed with a film thickness optimum for preventing reflection. The light shielding film material layer 39A is formed of a material excellent in light shielding properties and workability, such as aluminum (Al) or tungsten (W).

  Next, a resist mask 47 is selectively formed on the light shielding film material layer 39A. The resist mask 47 has an opening in a portion corresponding to the photodiode PD, and is formed in a lattice shape in plan view so that a portion corresponding to each pixel boundary remains. Then, as shown in FIG. 6B, the light shielding film material layer 39A is selectively removed by etching through the resist mask 47 to form the light shielding film 39 at each pixel boundary. Etching can be wet etching or dry etching. Dry etching is preferable because the fine line width of the light shielding film 39 can be obtained with high accuracy.

  Next, as shown in FIG. 7C, a planarization film 41 is formed on the antireflection film including the light shielding film 39. The planarizing film 41 is formed by applying an organic material such as a resin.

  Next, as illustrated in FIG. 7D, for example, an on-chip color filter 42 and an on-chip microlens 43 having a Bayer arrangement are sequentially formed on the planarization film 41. In this way, the solid-state imaging device 21 of the target first embodiment is obtained.

  According to the manufacturing method of the solid-state imaging device of the present embodiment, the light shielding film 39 is selectively formed on the back surface 22B which is the light receiving surface of the semiconductor substrate 22 via the antireflection film 36 at the portion corresponding to the pixel boundary. Therefore, the light shielding film 39 can be formed at a position close to the light receiving surface 34. By forming the light shielding film 39 at a position close to the light receiving surface, it is possible to prevent light that cannot be collected by the on-chip microlens 43 from entering the adjacent pixels. Further, this light shielding film prevents the diffracted light, which is a cause of Mg flare, from entering the effective pixels. Since the antireflection film 36 is formed on the light receiving surface 34, reflection on the light receiving surface 34 of the back surface 22B of the substrate can be suppressed, and high sensitivity can be achieved. Furthermore, since the on-chip color filter 42 and the on-chip microlens 43 are formed via the planarization film 41, the lens height of the on-chip microlens 43 can be made uniform within the effective screen area. Therefore, the present manufacturing method reduces the optical color mixture, suppresses the incidence of diffracted light to the effective pixel, reduces the Mg flare, and achieves a uniform and high sensitivity within the effective pixel region. Can be manufactured easily and with high accuracy.

<3. Second Embodiment>
[Configuration example of solid-state imaging device]
FIG. 8 shows a second embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. As in the first embodiment, the solid-state imaging device 51 according to the second embodiment includes, for example, a pixel region 23 in which a plurality of pixels are arranged on a semiconductor substrate 22 made of silicon, and a peripheral region of the pixel region 23 (not shown). It is configured by forming an arranged peripheral circuit portion. A logic circuit is formed in the peripheral circuit portion. The unit pixel 24 includes a photodiode PD serving as a photoelectric conversion unit and a plurality of pixel transistors Tr. The photodiode PD is formed so as to extend over the entire thickness direction of the semiconductor substrate 22, and in the first conductivity type, in this example, the n-type semiconductor region 25 and the second conductivity type so as to face both the front and back surfaces of the substrate, in this example, p. It is configured as a pn junction type photodiode with the type semiconductor region 26. The p-type semiconductor regions facing both the front and back surfaces of the substrate also serve as charge storage regions for dark current suppression.

  Each pixel 24 including the photodiode PD and the pixel transistor Tr is separated by an element isolation region 27. The element isolation region 27 is formed of a p-type semiconductor region and is grounded, for example. In the pixel transistor Tr, an n-type source region and drain region (not shown) are formed in a p-type semiconductor well region 28 formed on the surface 22A side of the semiconductor substrate 22, and a gate insulating film is formed on the substrate surface between both regions. The gate electrode 29 is formed. In the figure, a plurality of pixel transistors are representatively represented by one pixel transistor Tr and are schematically represented by a gate electrode 29.

  On the surface 22 </ b> A of the semiconductor substrate 22, a so-called multilayer wiring layer 33 is formed, in which a plurality of layers of wirings 32 are arranged via an interlayer insulating film 31. Since no light is incident on the multilayer wiring layer 33 side, the layout of the wiring 32 can be freely set.

  An insulating film is formed on the substrate back surface 22B that becomes the light receiving surface 34 of the photodiode PD. This insulating film is formed of an antireflection film 36 in this example. The antireflection film 36 is formed of a multilayer film having different refractive indexes. In this example, the antireflection film 36 is formed of a two-layer film of a hafnium oxide (HfO 2) film 37 and a silicon oxide film 38.

  In the present embodiment, in particular, an insulating film 52 is formed on the antireflection film 36, and a light shielding film 39 is formed at the pixel boundary on the insulating film 52. The insulating film 52 has an optically appropriate value for the film type and film thickness. The insulating film 52 is preferably formed of, for example, a silicon oxide film, and the film thickness is set to be sufficiently thicker than at least the film thickness of the antireflection film 36. The light shielding film 39 may be any material that shields light, but a material such as aluminum (Al), tungsten (W), or the like that has a strong light shielding property and can be processed with high precision by fine processing, for example, etching, or It is preferable to form a copper (Cu) film.

The insulating film 52 is preferably a film having a large refractive index difference from the upper high-refractive index film constituting the antireflection film 36, in this example, the hafnium oxide (HfO 2) film 38, for example, a silicon oxide film. For example, when the insulating film 52 is formed of a silicon nitride (SiN) film having a refractive index close to that of a hafnium oxide (HfO ₂ ) film, the film thickness of the hafnium oxide film 38 is substantially increased. It becomes inappropriate as an antireflection film.

  A planarizing film 41 is formed on the insulating film 52 including the light shielding film 39, and an on-chip color filter 42 and an on-chip microlens 43 thereon are sequentially formed on the planarizing film 41. The planarization film 41 can be formed of an organic material such as resin, for example. For example, a Bayer color filter is used as the on-chip color filter. The light L is incident from the substrate rear surface 22B side, condensed by the on-chip microlens 43, and received by each photodiode PD.

  According to the back-illuminated solid-state imaging device 51 according to the second embodiment, the insulating film 52 having a thickness larger than that of the antireflection film 36 is formed on the antireflection film 39, and the pixel boundary on the insulating film 52 is formed. Since the light shielding film 36 is formed in the corresponding portion, the optimum antireflection film 36 is maintained. That is, the light shielding film 36 is patterned by selective etching after a light shielding film material layer is formed on the entire surface. In this selective etching, even if the base is damaged by etching, it is the insulating film 52 that is damaged, and the antireflection film 36 is not affected at all.

  In order to stably produce sensitivity and spectral characteristics in a back-illuminated solid-state imaging device, it is necessary to stably control the thickness of the antireflection film 36 formed on the silicon interface in advance. If the film thickness of the antireflection film 36 is reduced during the processing of the light shielding film 36, the sensitivity and spectral characteristics may vary. Since the insulating film 52 is formed on the antireflection film 36 before the light shielding film 36 is formed, sensitivity and spectral characteristics are stabilized.

  The solid-state imaging device 51 of the second embodiment has the same effects as those described in the first embodiment. That is, since the light shielding film 39 is formed at the pixel boundary very close to the light receiving surface 34, the light toward the adjacent pixels is shielded without being condensed by the on-chip microlens 43. That is, the light shielding film 39 at the pixel boundary can prevent light from entering adjacent pixels and reduce optical color mixing. Further, even if light is incident on the solid-state imaging device 21 disposed in the package and the partially reflected diffracted light is re-reflected by the seal glass and enters the solid-state imaging device 51, the light shielding film 39 at the pixel boundary is used. The incidence of diffracted light is prevented. For this reason, Mg flare can be reduced particularly in high-luminance light source photography.

  Further, since the on-chip microlens 43 is formed through the planarization film 41, all the lens heights of the on-chip microlens 43 on the pixel region are the same. In particular, the lens height of the on-chip microlens 43 in the effective pixel region is the same, and the step d does not occur between the peripheral portion and the central region in the effective pixel region shown in FIG. Therefore, the same luminance can be obtained over the entire screen, that is, there is no occurrence of sensitivity unevenness, and image quality can be improved.

  As described above, the solid-state imaging device 51 can reduce the optical color mixture and reduce the Mg flare by arranging the light shielding film 39 at the pixel boundary close to the light receiving surface. Sensitivity unevenness does not occur and a high-quality image can be taken. Thus, the backside illumination type solid-state imaging device 51 according to the second embodiment can improve the image quality.

[Example of Manufacturing Method of Solid-State Imaging Device of Second Embodiment]
9 and 10 show a method for manufacturing the solid-state imaging device 51 of the second embodiment. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. Reference numerals of omitted parts refer to FIG.

  Similar to the above, first, photodiode PD corresponding to each pixel separated by element isolation region 27 by the p-type semiconductor region is formed in a region where a pixel region of silicon semiconductor substrate 22, for example, is to be formed. The photodiode PD has a pn junction composed of an n-type semiconductor region 25 extending over the entire substrate thickness direction and a p-type semiconductor region 26 in contact with the n-type semiconductor region 25 and facing the front and back surfaces 22A and 22B of the substrate. Formed. A p-type semiconductor well region 28 that is in contact with the element isolation region is formed in a region corresponding to each pixel on the substrate surface 22 </ b> A, and a plurality of pixel transistors Tr are formed in the p-type semiconductor well region 28. Each pixel transistor Tr is formed by a source region and a drain region, a gate insulating film, and a gate electrode 29. Furthermore, a multilayer wiring layer 33 in which a plurality of layers of wirings 32 are arranged via an interlayer insulating film 31 is formed on the substrate surface 22A.

Next, as shown in FIG. 9A, an insulating film is formed on the back surface 22B of the substrate serving as a light receiving surface in this example, and an insulating film 52 is formed on the antireflective film 36. A light shielding film material layer 39 </ b> A is formed on the insulating film 52. The insulating film 52 can be formed of, for example, a silicon oxide (SiO ₂ ) film. The film thickness of the insulating film 52 is selected to be sufficiently thicker than the film thickness of the antireflection film 36. The antireflection film 36 is formed of a plurality of films having different refractive indexes. In this example, the antireflection film 36 is formed of a two-layer film in which a silicon oxide (SiO ₂ ) film 37 and a hafnium oxide (HfO ₂ ) film 38 are stacked from the substrate back surface 22B side. . Each of the silicon oxide film 37 and the hafnium oxide film 38 is formed with a film thickness optimum for preventing reflection. The light shielding film material layer 39A is formed of a material excellent in light shielding properties and workability, such as aluminum (Al) or tungsten (W).

  Next, a resist mask 47 is selectively formed on the light shielding film material layer 39A. The resist mask 47 has an opening in a portion corresponding to the photodiode PD, and is formed in a lattice shape in plan view so that a portion corresponding to each pixel boundary remains. Then, as shown in FIG. 9B, the light shielding film material layer 39A is selectively removed by etching through the resist mask 47 to form the light shielding film 39 at each pixel boundary. Etching can be wet etching or dry etching. Dry etching is preferable because the fine line width of the light shielding film 39 can be obtained with high accuracy. In the selective etching of the light shielding film material layer 39A, the insulating film 5 is not received even if the base is damaged by etching.

  Next, as shown in FIG. 10C, a planarizing film 41 is formed on the antireflection film including the light shielding film 39. The planarizing film 41 is formed by applying an organic material such as a resin.

  Next, as illustrated in FIG. 10D, for example, an on-chip color filter 42 and an on-chip microlens 43 having a Bayer arrangement are sequentially formed on the planarization film 41. Thus, the solid-state imaging device 51 of the target second embodiment is obtained.

  According to the method for manufacturing the solid-state imaging device of the present embodiment, after forming the insulating film 52 sufficiently thicker than the antireflection film 36 on the antireflection film 36, the pixel boundary portion on the insulating film 52 is formed. A light shielding film 39 is formed. For this reason, in the selective processing by etching the light shielding film 39, even if etching damage is given to the base film, the antireflection film 36 is not damaged by etching, and the antireflection film 36 having an optimum thickness is formed. Can do.

  In addition, the same effects as described in the method of manufacturing the solid-state imaging device according to the first embodiment can be obtained. That is, the light shielding film 39 is selectively formed on the back surface 22B, which is the light receiving surface of the semiconductor substrate 22, via the antireflection film 36 and the insulating film 52 at a portion corresponding to the pixel boundary. 34 can be formed at a position close to 34. By forming the light shielding film 39 at a position close to the light receiving surface, it is possible to prevent light that cannot be collected by the on-chip microlens 43 from entering the adjacent pixels. In addition, the light shielding film 39 prevents the diffracted light, which is a cause of Mg flare, from entering the effective pixels. Since the on-chip color filter 42 and the on-chip microlens 43 are formed through the planarization film 41, the lens height of the on-chip microlens 43 can be made uniform within the effective screen area.

  Furthermore, in the manufacturing method of the present embodiment, since the antireflection film 36 that maintains the optimum film thickness is formed on the light receiving surface 34, the reflection on the light receiving surface 34 of the back surface 22B of the substrate is further suppressed, and high sensitivity is achieved. I can plan. Therefore, this manufacturing method reduces optical color mixing, suppresses the incidence of diffracted light to effective pixels, reduces Mg flare, and achieves higher performance with uniform and high sensitivity in the effective pixel region. The solid-state imaging device of the second embodiment can be manufactured easily and with high accuracy.

  In the solid-state imaging devices 21 and 51 of the above-described embodiments, the opening shape of the light shielding film 39 can be appropriately selected according to the light collection state. 11A to 11C show examples of the opening shape of the light shielding film 39. FIG. The light shielding film 39 shown in FIG. 11A has a rectangular opening 39a as an opening shape. Therefore, the shape of the light receiving surface of the photodiode PD is a quadrangle. The maximum sensitivity is obtained when the rectangular opening 39a is provided.

  The light shielding film 39 shown in FIG. 11B is configured to have a polygonal opening shape, in this example, an octagonal opening 39b. Therefore, the shape of the light receiving surface of the photodiode PD is an octagon. When the octagonal opening 39b is provided, the flare in the diagonal direction can be reduced as compared with the quadrangular shape.

  The light shielding film 39 shown in FIG. 11C has a circular opening 39c as an opening shape. Therefore, the shape of the light receiving surface of the photodiode PD is circular. When the opening 39c having a circular shape (rectangular inscribed circle in FIG. 11A) is provided, flare generated in the middle direction between the horizontal and the diagonal can be reduced. However, the sensitivity is the lowest among FIGS. 11A to 11C.

  11A to 11C, the pixel boundary has a vertically and horizontally symmetrical shape, and the center O of the photodiode PD formed in the semiconductor substrate 22 and the light shielding film opening center O coincide with each other. The light shielding film 39 is formed. By making the center of the photodiode PD coincide with the center of the light shielding film opening, symmetry depending on the incident angle can be maintained, and isotropic sensitivity characteristics can be obtained over the entire screen.

<4. Third Embodiment>
[Configuration example of solid-state imaging device]
FIG. 12 shows a third embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In the solid-state imaging device 56 according to the third embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, a logic circuit (not shown) is formed in the peripheral circuit portion 57, and the back surface 22B of the semiconductor substrate 22 is formed. An antireflection film 36 and an insulating film 52 are sequentially formed thereon.

  In the present embodiment, a lattice-shaped light shielding film 39 at the pixel boundary is formed on the insulating film 52 corresponding to the pixel region 23, and the peripheral circuit portion 57 and the optical black level region 23 B of the pixel region are formed. A continuous light shielding film 39 is formed on the corresponding insulating film 52. The optical black level region 23B is formed on the outer periphery of the effective pixel region 23A. The light shielding film 39 at the pixel boundary and the continuous light shielding film 39 extending over the peripheral circuit 57 and the optical black level region 23B are simultaneously formed of the same material film. The light shielding film 39 at the pixel boundary and the light shielding film 39 extending over the peripheral circuit 57 and the optical black level region 23B are continuously and integrally formed with each other.

In the present embodiment, a planarization film 41 is further formed on the insulating film 52 including the light shielding films 39, 39, and the on-chip color filter 42 and the on-chip micro are formed on the region corresponding to the pixel region 23 of the planarization film 41. A lens 43 is formed. Also in the peripheral circuit portion 57, a multilayer wiring layer in which a plurality of layers of wiring are arranged via an interlayer insulating film is formed on the substrate surface side.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

  The solid-state imaging device 56 according to the third embodiment has a configuration in which the light shielding film 39 continuous from the peripheral circuit unit 57 to the optical black level region 23B and the lattice-shaped light shielding film 39 at the pixel boundary are formed simultaneously. Therefore, the level difference due to the light shielding film 39 is reduced. Thereby, the lens height of the on-chip microlens 43 in the effective pixel region can be made uniform, and a uniform condensing state can be obtained in the entire effective pixel.

  In addition, the second embodiment is such that the optical color mixture to the adjacent pixels due to the light that cannot be condensed by the on-chip micro lens 43 is reduced, and the incidence of Mg flares is reduced by suppressing the incidence of diffracted light to the effective pixels. The same effects as described in the embodiment are obtained. Thus, the backside illumination type solid-state imaging device 56 according to the third embodiment can improve the image quality.

<5. Fourth Embodiment>
[Configuration example of solid-state imaging device]
FIG. 13 shows a fourth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. In the solid-state imaging device 59 according to the fourth embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, a logic circuit (not shown) is formed in the peripheral circuit portion 57, and the back surface 22B of the semiconductor substrate 22 is formed. An antireflection film 36 and an insulating film 52 are sequentially formed thereon.

  On the insulating film 52 corresponding to the pixel region 23, a lattice-shaped light shielding film 39 is formed corresponding to the pixel boundary, and on the insulating film 52 corresponding to the peripheral circuit portion 57 and the optical black level region 23B of the pixel region. A continuous light shielding film 39 is formed. The optical black level region 23B is formed on the outer periphery of the effective pixel region 23A. The light shielding film 39 at the pixel boundary and the continuous light shielding film 39 extending over the peripheral circuit 57 and the optical black level region 23B are simultaneously formed of the same material film. The light shielding film 39 at the pixel boundary and the light shielding film 39 extending over the peripheral circuit 57 and the optical black level region 23B are continuously and integrally formed with each other.

In the present embodiment, the light shielding film 39 is connected to the ground (GND) region of the semiconductor substrate 22, that is, the element isolation region 27 by the p-type semiconductor region. As described above, the light shielding film 39 is formed of, for example, aluminum (Al) or tungsten (W). The light shielding film 39 is preferably connected to the p-type semiconductor region of the element isolation region 27 via a barrier metal layer 60 such as Ti or TiN as shown in FIG. A ground potential (ground potential) is applied to the light shielding film 39 through the p-type semiconductor region of the element isolation region 27.

As shown in FIG. 14, the light shielding film 39 is connected through the contact portion 61 in the element isolation region 27 located outside the optical black level region 23B of the pixel region. The light shielding film 39 can also be connected to the contact portion 62 of the element isolation region 27 in the effective pixel region 23A. In the pixel region 23, the formation of the contact portion 61 must be avoided because the formation of the contact portion 61 may damage silicon and cause white spots. Therefore, it is preferable to connect the light shielding film 39 to the element isolation region outside the optical black level region.
Since other configurations are the same as those described in the second embodiment and the third embodiment, portions corresponding to those in FIG. 8 and FIG.

  According to the solid-state imaging device 59 according to the fourth embodiment, the light shielding film 39 is grounded through the element isolation region 27, which is a ground region, so that the potential of the light shielding film 39 is fixed, and the photodiode PD directly below is fixed. Thus, noise during darkness can be reduced.

  In addition, reduction of optical color mixture to adjacent pixels by the light shielding film 39 at the pixel boundary, reduction of Mg flare generation by suppressing incidence of diffracted light to the effective pixels, and uniform sensitivity in the effective pixel area by the planarization film 41 The same effects as described in the second embodiment are obtained. In addition, the same effect as described in the third embodiment can be obtained, for example, the level difference due to the light shielding film 39 is reduced and a uniform light collection state can be obtained in the entire effective pixel. Thus, the back-illuminated solid-state imaging device 59 according to the fourth embodiment can improve the image quality.

<6. Fifth embodiment>
[Configuration example of solid-state imaging device]
FIG. 15 shows a fifth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. In the solid-state imaging device 63 according to the fifth embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, and a logic circuit is formed in a peripheral circuit portion (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the substrate back surface 22 </ b> B serving as a light receiving surface of the photodiode PD, and a lattice-shaped light shielding film 39 is formed at a pixel boundary on the insulating film 52.

In the present embodiment, the inner lens 64 is formed on the corresponding upper portion of each photodiode PD. The in-layer lens 64 is configured to form a convex lens in this example. The intralayer lens 64 can be formed of, for example, a nitride film.
A planarizing film 67 made of, for example, an organic film is formed on the in-layer lens 64, and the on-chip color filter 42 and the on-chip microlens 43 are sequentially formed on the planarizing film 67. In other words, the intralayer lens 64 in the present embodiment is formed below the on-chip color filter 42, that is, between the antireflection film 36 and the on-chip color filter 42.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

According to the solid-state imaging device 63 according to the fifth embodiment, the inner lens 64 is formed between the antireflection film 36 and the on-chip color filter 42 corresponding to each photodiode PD. Condensing efficiency to PD is further improved. Thereby, the optical color mixture to an adjacent pixel can further be reduced.
In addition, reduction of optical color mixture to adjacent pixels by the light shielding film 39 at the pixel boundary, reduction of Mg flare generation by suppressing incidence of diffracted light to the effective pixels, and uniform sensitivity in the effective pixel area by the planarization film 41 The same effects as described in the second embodiment are obtained. Thus, the backside illumination type solid-state imaging device 63 according to the fifth embodiment can improve the image quality.

<7. Sixth Embodiment>
[Configuration example of solid-state imaging device]
FIG. 16 shows a sixth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. In the solid-state imaging device 67 according to the sixth embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, and a logic circuit is formed in a peripheral circuit section (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the substrate back surface 22 </ b> B serving as a light receiving surface of the photodiode PD, and a lattice-shaped light shielding film 39 is formed at a pixel boundary on the insulating film 52. Further, an on-chip color filter 42 and an on-chip microlens 43 are formed on the insulating film 52 including the light shielding film 39 via the planarization film 41.

In the present embodiment, an antireflection film 68 is formed on the surface of each on-chip microlens 43 along the lens surface. The antireflection film 68 can be formed of, for example, a single layer of a silicon oxide film. The antireflection film 68 can also be formed of other multilayer films.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

According to the solid-state imaging device 67 according to the sixth embodiment, by forming the antireflection film 68 on the surface of the on-chip microlens 43, the on-chip microlens 43 and the on-chip color filter 42 at the time of photographing with high luminance light. The reflectance due to can be reduced. Therefore, it is possible to further reduce the incidence of diffracted light on the effective pixels and to further reduce Mg flare.
In addition, reduction of optical color mixture to adjacent pixels by the light shielding film 39 at the pixel boundary, reduction of Mg flare generation by suppressing incidence of diffracted light to the effective pixels, and uniform sensitivity in the effective pixel area by the planarization film 41 The same effects as described in the second embodiment are obtained. Thus, the backside illumination type solid-state imaging device 67 according to the sixth embodiment can improve the image quality.

<8. Seventh Embodiment>
[Configuration example of solid-state imaging device]
FIG. 17 shows a seventh embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. In the solid-state imaging device 71 according to the seventh embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, and a logic circuit is formed in a peripheral circuit portion (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the substrate back surface 22 </ b> B serving as a light receiving surface of the photodiode PD, and a lattice-shaped light shielding film 39 is formed at a pixel boundary on the insulating film 52. Further, an on-chip color filter 42 and an on-chip microlens 43 are formed on the insulating film 52 including the light shielding film 39 via the planarization film 41.

In this embodiment, a transparent flattening film 72 that is uniformly continuous is formed on each on-chip microlens 43. The planarizing film 72 is formed of a material film having a refractive index lower than that of the on-chip microlens 43, for example, an organic film such as a resin.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

According to the solid-state imaging device 71 according to the seventh embodiment, since the flattening film 72 that is uniformly continuous is formed on each on-chip microlens 43, the on-chip microlens 43 during high-intensity light source photography, The diffraction phenomenon by the on-chip color filter 42 can be suppressed. Therefore, it is possible to suppress the incidence of diffracted light on the effective pixel and to further reduce Mg flare.
In addition, reduction of optical color mixture to adjacent pixels by the light shielding film 39 at the pixel boundary, reduction of Mg flare generation by suppressing incidence of diffracted light to the effective pixels, and uniform sensitivity in the effective pixel area by the planarization film 41 The same effects as described in the second embodiment are obtained. Thus, the backside illumination type solid-state imaging device 71 according to the seventh embodiment can improve the image quality.

<9. Eighth Embodiment>
[Configuration example of solid-state imaging device]
FIG. 18 shows an eighth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. In the solid-state imaging device 74 according to the eighth embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, and a logic circuit is formed in a peripheral circuit section (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the substrate back surface 22 </ b> B serving as a light receiving surface of the photodiode PD, and a lattice-shaped light shielding film 39 is formed at a pixel boundary on the insulating film 52. Further, the on-chip color filter 42 and the on-chip microlens 75 are formed on the insulating film 52 including the light shielding film 39 via the planarizing film 41.

In the present embodiment, the on-chip microlens 75 is formed of a rectangular lens, and the transparent flattening film 72 that is uniformly continuous is formed on each rectangular on-chip microlens 75. The planarizing film 72 is formed of a material film having a refractive index lower than that of the on-chip microlens 43, for example, an organic film such as a resin.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

According to the solid-state imaging device 74 according to the eighth embodiment, since the flattening film 72 that is uniformly continuous is formed on each on-chip microlens 75, the on-chip microlens 75 at the time of high-intensity light source photography The diffraction phenomenon by the on-chip color filter 42 can be suppressed. Therefore, it is possible to suppress the incidence of diffracted light on the effective pixel and to further reduce Mg flare. In addition, since the on-chip microlens 75 is formed of a rectangular lens, the lens height can be increased, and the light collecting ability of the on-chip microlens can be greatly improved.
In addition, reduction of optical color mixture to adjacent pixels by the light shielding film 39 at the pixel boundary, reduction of Mg flare generation by suppressing incidence of diffracted light to the effective pixels, and uniform sensitivity in the effective pixel area by the planarization film 41 The same effects as described in the second embodiment are obtained. Thus, the backside illumination type solid-state imaging device 74 according to the eighth embodiment can improve the image quality.

<10. Ninth Embodiment>
[Configuration example of solid-state imaging device]
FIG. 19 shows a ninth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. In the solid-state imaging device 77 according to the ninth embodiment, each photodiode PD is formed in the pixel region 23 of the semiconductor substrate 22, and a logic circuit is formed in a peripheral circuit portion (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the substrate back surface 22 </ b> B serving as a light receiving surface of the photodiode PD, and a lattice-shaped light shielding film 39 is formed at a pixel boundary on the insulating film 52.

In this embodiment, the planarization film 41 is omitted, the on-chip color filter 42 is formed directly on the antireflection film 36 including the light shielding film 39, and the on-chip microlens 43 is formed thereon. The Each color filter of the on-chip color filter 42 is partially formed between the light shielding films 39.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

According to the solid-state imaging device 77 according to the ninth embodiment, since the on-chip color filter 42 is formed directly on the antireflection film 36 including the light shielding film 39, sensitivity is increased, optical color mixing, and Mg flare are reduced. To do.
In addition, reduction of optical color mixture to adjacent pixels by the light shielding film 39 at the pixel boundary, reduction of Mg flare generation by suppressing incidence of diffracted light to the effective pixels, and uniform sensitivity in the effective pixel area by the planarization film 41 The same effects as described in the second embodiment are obtained. Thus, the backside illumination type solid-state imaging device 77 according to the ninth embodiment can improve the image quality.

<11. 10th Embodiment>
[Configuration example of solid-state imaging device]
FIG. 20 shows a tenth embodiment of a solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. The solid-state imaging device 79 according to the tenth embodiment has a configuration in which the light shielding film 39 at the pixel boundary is omitted from the above-described sixth embodiment (see FIG. 16). The peripheral circuit portion and the optical black level region are shielded from light as in the conventional example.

  That is, the solid-state imaging device 79 of the present embodiment is formed by forming each photodiode PD in the pixel region 23 of the semiconductor substrate 22 and forming a logic circuit in a peripheral circuit section (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the back surface 22B of the substrate serving as the light receiving surface of the photodiode PD, and the on-chip color filter 42 and the on-chip microlens are disposed on the insulating film 52 via the planarizing film 41. 43 is formed.

Furthermore, in the present embodiment, an antireflection film 68 is formed on the surface of each on-chip microlens 43 so as to follow the lens surface. The antireflection film 68 can be formed of, for example, a single layer of a silicon oxide film. The antireflection film 68 can also be formed of other multilayer films.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

  According to the solid-state imaging device 79 according to the tenth embodiment, the anti-reflection film 68 is formed on the surface of the on-chip microlens 43, so that the on-chip microlens 43 and the on-chip color filter 42 at the time of photographing with high luminance light. The reflectance due to can be reduced. Therefore, it is possible to further reduce the incidence of diffracted light on the effective pixels and to further reduce Mg flare. Thus, the backside illumination type solid-state imaging device 79 according to the tenth embodiment can improve the image quality.

<12. Eleventh embodiment>
[Configuration example of solid-state imaging device]
FIG. 21 shows an eleventh embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. The solid-state imaging device 81 according to the eleventh embodiment has a configuration in which the light shielding film 39 at the pixel boundary is omitted from the above-described seventh embodiment (see FIG. 17). The peripheral circuit portion and the optical black level region are shielded from light as in the conventional example.

  That is, the solid-state imaging device 81 according to the present embodiment is formed by forming each photodiode PD in the pixel region 23 of the semiconductor substrate 22 and forming a logic circuit in a peripheral circuit portion (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the back surface 22B of the substrate serving as the light receiving surface of the photodiode PD, and the on-chip color filter 42 and the on-chip microlens are disposed on the insulating film 52 via the planarizing film 41. 43 is formed.

Furthermore, in this embodiment, a transparent flattening film 72 that is uniformly continuous is formed on each on-chip microlens 43. The planarizing film 72 is formed of a material film having a refractive index lower than that of the on-chip microlens 43, for example, an organic film such as a resin.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

According to the solid-state imaging device 81 according to the eleventh embodiment, since the flattening film 72 that is uniformly continuous is formed on each on-chip microlens 43, the on-chip microlens 43 during high-intensity light source photography, The diffraction phenomenon by the on-chip color filter 42 can be suppressed. Therefore, it is possible to suppress the incidence of diffracted light on the effective pixel and to further reduce Mg flare.
Thus, the backside illumination type solid-state imaging device 81 according to the eleventh embodiment can improve the image quality.

<13. Twelfth Embodiment>
[Configuration example of solid-state imaging device]
FIG. 22 shows a twelfth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of the present embodiment is a backside illumination type CMOS solid-state imaging device. In these figures, a part of the substrate surface side is omitted and only the cross-sectional structure of the main part is shown. The omitted part is the same as in FIG. The solid-state imaging device 83 according to the twelfth embodiment has a configuration in which the light shielding film 39 at the pixel boundary is omitted from the above-described eighth embodiment (see FIG. 18). The peripheral circuit portion and the optical black level region are shielded from light as in the conventional example.

  That is, the solid-state imaging device 81 according to the present embodiment is formed by forming each photodiode PD in the pixel region 23 of the semiconductor substrate 22 and forming a logic circuit in a peripheral circuit portion (not shown). Each pixel including the photodiode PD and the pixel transistor is separated in the element isolation region 27. An antireflection film 36 and an insulating film 52 are formed on the back surface 22B of the substrate serving as the light receiving surface of the photodiode PD, and the on-chip color filter 42 and the on-chip microlens are disposed on the insulating film 52 via the planarizing film 41. 75 is formed.

In the present embodiment, the on-chip microlens 75 is formed of a rectangular lens, and the transparent flattening film 72 that is uniformly continuous is formed on each rectangular on-chip microlens 75. The planarizing film 72 is formed of a material film having a refractive index lower than that of the on-chip microlens 43, for example, an organic film such as a resin.
Since other configurations are the same as those described in the second embodiment, portions corresponding to those in FIG.

  According to the solid-state imaging device 83 according to the twelfth embodiment, since the flattening film 72 that is uniformly continuous is formed on each on-chip microlens 75, the on-chip microlens 75 during high-intensity light source photography, The diffraction phenomenon by the on-chip color filter 42 can be suppressed. Therefore, it is possible to suppress the incidence of diffracted light on the effective pixel and to further reduce Mg flare. In addition, since the on-chip microlens 75 is formed of a rectangular lens, the lens height can be increased, and the light collecting ability of the on-chip microlens can be greatly improved. Thus, the backside illumination type solid-state imaging device 74 according to the twelfth embodiment can improve the image quality.

  In the third to twelfth embodiments, the insulating film 52 may be omitted as in the first embodiment. The characteristic configurations in the first to twelfth embodiments may be combined with each other.

<14. Thirteenth Embodiment>
[Configuration example of solid-state imaging device]
FIG. 23 shows a thirteenth embodiment of the solid-state imaging device according to the present invention. The solid-state imaging device of this embodiment is a surface irradiation type CMOS solid-state imaging device. The solid-state imaging device 85 according to the thirteenth embodiment includes, for example, a pixel region (so-called imaging region) 23 in which a plurality of pixels are arranged on a semiconductor substrate 22 made of silicon, and a periphery that is arranged around the pixel region 23 (not shown). A circuit part is formed and configured. The unit pixel 24 includes a photodiode PD serving as a photoelectric conversion unit and a plurality of pixel transistors Tr. The photodiode PD is formed so as to extend over the entire thickness direction of the semiconductor substrate 22, and in the first conductivity type, in this example, the n-type semiconductor region 25 and the second conductivity type so as to face both the front and back surfaces of the substrate, in this example, p. It is configured as a pn junction type photodiode with the type semiconductor region 26. The p-type semiconductor regions facing both the front and back surfaces of the substrate also serve as hole charge accumulation regions for dark current suppression.

  Each pixel 24 including the photodiode PD and the pixel transistor Tr is separated by an element isolation region 27. The element isolation region 27 is formed of a p-type semiconductor region and is grounded, for example. In the pixel transistor Tr, an n-type source region and drain region (not shown) are formed in a p-type semiconductor well region 28 formed on the surface 22A side of the semiconductor substrate 22, and a gate insulating film is formed on the substrate surface between both regions. The gate electrode 29 is formed. In the figure, a plurality of pixel transistors are representatively represented by one pixel transistor Tr and are schematically represented by a gate electrode 29.

  In the present embodiment, an insulating film is formed on the surface 22A serving as the light receiving surface of the semiconductor substrate 22 on which the pixel transistor Tr is formed via a planarizing film 86 made of an insulating film such as a silicon oxide film. This insulating film is formed of an antireflection film 36 in this example. The antireflection film 36 is formed of a multilayer film having different refractive indexes. In this example, the antireflection film 36 is formed of a two-layer film of a hafnium oxide (HfO 2) film 37 and a silicon oxide film 38.

  Further, a light shielding film 39 is formed at the pixel boundary on the antireflection film 36. The light-shielding film 39 may be any material that shields light as described above. However, as a material having a strong light-shielding property and capable of being precisely processed by microfabrication, for example, etching, a metal such as aluminum (Al) or tungsten. It is preferable to form with the film of (W). The light shielding film 39 can also be formed of polysilicon, for example.

  On the antireflection film 36 including the light shielding film 39, a so-called multilayer wiring layer 33 is formed, in which a plurality of layers of wirings 32 are arranged via an interlayer insulating film 31. On the multilayer wiring layer 33, an on-chip color filter 42 and an on-chip microlens 43 thereon are sequentially formed via a planarizing film 86. The light L is incident from the substrate surface 22A side, collected by the on-chip microlens 43, and received by each photodiode PD.

  According to the surface irradiation type solid-state imaging device 85 according to the thirteenth embodiment, since the light shielding film 39 is formed at the pixel boundary very close to the light receiving surface 34, the on-chip microlens 43 cannot completely collect the light. Light traveling toward the adjacent pixel is blocked. That is, the light shielding film 39 at the pixel boundary can prevent light from entering adjacent pixels and reduce optical color mixing. Thus, the solid-state imaging device 85 of the thirteenth embodiment can improve the image quality.

<15. 14th Embodiment>
[Configuration example of solid-state imaging device]
FIG. 24 shows a fourteenth embodiment of a solid-state imaging device according to the present invention. The solid-state imaging device of this embodiment is a surface irradiation type CMOS solid-state imaging device. Similarly to the thirteenth embodiment, the solid-state imaging device 89 according to the fourteenth embodiment includes, for example, a pixel region (so-called imaging region) 23 in which a plurality of pixels are arranged on a semiconductor substrate 22 made of silicon, and a pixel (not shown). A peripheral circuit portion disposed around the region 23 is formed and configured. A logic circuit is formed in the peripheral circuit portion. The unit pixel 24 includes a photodiode PD serving as a photoelectric conversion unit and a plurality of pixel transistors Tr. The photodiode PD is formed so as to extend over the entire thickness direction of the semiconductor substrate 22, and in the first conductivity type, in this example, the n-type semiconductor region 25 and the second conductivity type so as to face both the front and back surfaces of the substrate, in this example, p. It is configured as a pn junction type photodiode with the type semiconductor region 26. The p-type semiconductor regions facing both the front and back surfaces of the substrate also serve as hole charge accumulation regions for dark current suppression.

  Each pixel 24 including the photodiode PD and the pixel transistor Tr is separated by an element isolation region 27. The element isolation region 27 is formed of a p-type semiconductor region and is grounded, for example. In the pixel transistor Tr, an n-type source region and drain region (not shown) are formed in a p-type semiconductor well region 28 formed on the surface 22A side of the semiconductor substrate 22, and a gate insulating film is formed on the substrate surface between both regions. The gate electrode 29 is formed. In the figure, a plurality of pixel transistors are representatively represented by one pixel transistor Tr and are schematically represented by a gate electrode 29.

  In the present embodiment, an insulating film is formed on the surface 22A serving as the light receiving surface of the semiconductor substrate 22 on which the pixel transistor Tr is formed via a planarizing film 86 made of an insulating film such as a silicon oxide film. This insulating film is formed of an antireflection film 36 in this example. The antireflection film 36 is formed of a multilayer film having different refractive indexes. In this example, the antireflection film 36 is formed of a two-layer film of a hafnium oxide (HfO 2) film 37 and a silicon oxide film 38.

  Further, an insulating film 52 is formed on the antireflection film 36, and a light shielding film 39 is formed at the pixel boundary on the insulating film 52. The insulating film 52 has an optically appropriate value for the film type and film thickness. The insulating film 52 can be formed of, for example, a silicon oxide film, and its film thickness is set to be sufficiently thicker than at least the film thickness of the antireflection film 36. The light-shielding film 39 may be any material that shields light, but a material such as aluminum (Al) or tungsten (W) is used as a material that has a strong light-shielding property and can be processed with high precision by fine processing, for example, etching. It is preferable to form. The light shielding film 39 can also be formed of polysilicon, for example.

  On the insulating film 52 including the light shielding film 39, a so-called multilayer wiring layer 33 is formed, in which a plurality of layers of wirings 32 are arranged with an interlayer insulating film 31 interposed therebetween. On the multilayer wiring layer 33, an on-chip color filter 42 and an on-chip microlens 43 thereon are sequentially formed via a planarizing film 86. The light L is incident from the substrate surface 22A side, collected by the on-chip microlens 43, and received by each photodiode PD.

  According to the surface irradiation type solid-state imaging device 89 according to the fourteenth embodiment, the insulating film 52 having a thickness larger than that of the antireflection film 36 is formed on the antireflection film 39, and the pixel boundary on the insulating film 52 is formed. Since the light shielding film 36 is formed in the corresponding portion, the optimum antireflection film 36 is maintained. That is, the light shielding film 36 is patterned by selective etching after a light shielding film material layer is formed on the entire surface. In this selective etching, even if the base is damaged by etching, it is the insulating film 52 that is damaged, and the antireflection film 36 is not affected at all.

  As in the thirteenth embodiment, since the light shielding film 39 is formed at the pixel boundary extremely close to the light receiving surface 87, the light that is not condensed by the on-chip microlens 43 is blocked. Is done. That is, the light shielding film 39 at the pixel boundary can prevent light from entering adjacent pixels and reduce optical color mixing. Thus, the solid-state imaging device 85 of the fourteenth embodiment can improve the image quality.

  In the solid-state imaging device of the above-described embodiment, the signal charge is an electron, the first conductivity type is n-type, and the second conductivity type is p-type. However, when the signal charge is a hole, the first conductivity type is The p-type can be used, and the second conductivity type can be the n-type. In this case, the conductivity type of the semiconductor region of the above-described embodiment is the opposite conductivity type.

<16. Fifteenth embodiment>
[Configuration example of electronic equipment]
The above-described solid-state imaging device according to the present invention can be applied to electronic devices such as a camera system such as a digital camera or a video camera, a mobile phone having an imaging function, or another device having an imaging function. .

  FIG. 25 shows a third embodiment applied to a camera as an example of an electronic apparatus according to the invention. The camera according to the present embodiment is an example of a video camera capable of capturing still images or moving images. The camera 91 according to this embodiment includes a solid-state imaging device 92, an optical system 93 that guides incident light to the light receiving sensor unit of the solid-state imaging device 92, a shutter device 94, and a drive circuit 95 that drives the solid-state imaging device 92. And a signal processing circuit 96 that processes an output signal of the solid-state imaging device 92.

  Any of the solid-state imaging devices of the above-described embodiments is applied to the solid-state imaging device 92. The optical system (optical lens) 93 forms image light (incident light) from the subject on the imaging surface of the solid-state imaging device 92. As a result, signal charges are accumulated in the solid-state imaging device 92 for a certain period. The optical system 93 may be an optical lens system including a plurality of optical lenses. The shutter device 94 controls a light irradiation period and a light shielding period for the solid-state imaging device 92. The drive circuit 95 supplies a drive signal for controlling the transfer operation of the solid-state imaging device 92 and the shutter operation of the shutter device 94. Signal transfer of the solid-state imaging device 92 is performed by a drive signal (timing signal) supplied from the drive circuit 95. The signal processing circuit 96 performs various signal processing. The video signal subjected to the signal processing is stored in a storage medium such as a memory or output to a monitor.

  According to the electronic device according to the fourth embodiment, since the solid-state imaging device according to the above-described embodiment is used as the solid-state imaging device 92, the image quality can be improved, and a highly reliable electronic device such as a camera is provided. Can be provided.

  21, 51, 57, 59, 63, 67, 71, 74, 77, 79, 81, 83... Backside illumination type solid-state imaging device, 22... Semiconductor substrate, 22 A .. Substrate surface, 22 B. , PD, photodiode, Tr, pixel transistor, 34, light-receiving surface, 36, antireflection film, 39, light-shielding film, 41, flattening film, 42, on-chip color filter, 43,. On-chip micro lens, 85, 89 .. Surface irradiation type solid-state imaging device

Claims (18)

A semiconductor substrate;
A pixel region in which a plurality of pixels each having a photoelectric conversion unit and a pixel transistor formed on the semiconductor substrate are arranged;
An element isolation region formed in the semiconductor substrate;
A light shielding film formed in the pixel region on the light receiving surface side of the semiconductor substrate ;
An antireflection film disposed between the light shielding film and the light receiving surface;
An on-chip color filter and an on-chip microlens provided on the light-receiving surface side of the semiconductor substrate via the light-shielding film;
Through said interlayer insulating film on the side opposite to the light receiving surface of the semiconductor substrate and a wiring layer obtained by forming a wiring of a plurality of layers,
The element isolation region is grounded;
The solid-state imaging device , wherein the light shielding film penetrates the antireflection film and is connected to the element isolation region on the light receiving surface . An insulating film is provided between the antireflection film and the light shielding film,
The light shielding film passes through the antireflection film and the insulating film and is connected to the element isolation region.
The solid-state imaging device according to claim 1. The light shielding film is connected to the element isolation region through a barrier metal layer.
The solid-state imaging device according to claim 1 or 2. The solid-state imaging device according to claim 1, wherein the light shielding film includes a light shielding film at a pixel boundary. The solid-state imaging device according to claim 4, further comprising an optical black level region light shielding film that is formed in the same layer and at the same time as the light shielding film at the pixel boundary. The solid-state imaging device according to claim 4, further comprising a light shielding film for a peripheral circuit portion that is formed in the same layer and at the same time as the light shielding film at the pixel boundary. The solid-state imaging device according to claim 1, further comprising a planarizing film directly on the light shielding film. The solid-state imaging device according to claim 7, wherein the on-chip color filter is formed on the planarizing film. The antireflection film has a hafnium oxide film.
The solid-state imaging device according to claim 1 . The antireflection film has a hafnium oxide film and a silicon oxide film arranged in order from the light receiving surface side.
The solid-state imaging device according to claim 1. The solid-state imaging device according to claim 1, wherein the light shielding film is formed of aluminum, tungsten, or copper. The photoelectric conversion part is formed so as to cover the entire area in the thickness direction of the semiconductor substrate.
The solid-state imaging device according to claim 1. The element isolation region was formed so as to cover the entire thickness direction of the semiconductor substrate.
The solid-state imaging device according to claim 1. The pixel transistor is provided on the opposite side of the light receiving surface of the semiconductor substrate.
The solid-state imaging device according to claim 1. A solid-state imaging device;
An optical system for guiding incident light to the solid-state imaging device;
A signal processing circuit for processing an output signal of the solid-state imaging device;
The solid-state imaging device
A semiconductor substrate;
A pixel region in which a plurality of pixels each having a photoelectric conversion unit and a pixel transistor formed on the semiconductor substrate are arranged;
An element isolation region formed in the semiconductor substrate;
A light shielding film formed in the pixel region on the light receiving surface side of the semiconductor substrate ;
An antireflection film disposed between the light shielding film and the light receiving surface;
An on-chip color filter and an on-chip microlens provided on the light-receiving surface side of the semiconductor substrate via the light-shielding film;
Through said interlayer insulating film on the side opposite to the light receiving surface of the semiconductor substrate and a wiring layer obtained by forming a wiring of a plurality of layers,
The element isolation region is grounded;
The electronic device wherein the light shielding film penetrates the antireflection film and is connected to the element isolation region on the light receiving surface . The electronic device according to claim 15 , wherein the light shielding film includes a light shielding film at a pixel boundary. The electronic apparatus according to claim 16, further comprising an optical black level region light-shielding film formed in the same layer and simultaneously with the light-shielding film at the pixel boundary. It has a light shielding film in the peripheral circuit portion that is formed in the same layer and at the same time as the light shielding film at the pixel boundary.
The electronic device according to claim 16 or 17.