Solid-state imaging device, method of manufacturing a solid-state imaging device, and electronic apparatus

Abstract

Disclosed is a solid-state imaging device including a plurality of pixels and a plurality of on-chip lenses. The plurality of pixels are arranged in a matrix pattern. Each of the pixels has a photoelectric conversion portion configured to photoelectrically convert light incident from a rear surface side of a semiconductor substrate. The plurality of on-chip lenses are arranged for every other pixel. The on-chip lenses are larger in size than the pixels. Each of color filters at the pixels where the on-chip lenses are present has a cross-sectional shape whose upper side close to the on-chip lens is the same in width as the on-chip lens and whose lower side close to the photoelectric conversion portion is shorter than the upper side.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a
∵S=h·tan θ,tan θ=(D−W)/2H

Here, H represents a height from the interface on the rear surface side of the semiconductor substrate 12 to the uppermost surface of the on-chip lens layer 203, and h represents a height from the interface on the rear surface side of the semiconductor substrate 12 to the uppermost surface of the color filter 202 right below the on-chip lens 203A. In addition, W represents the width of the pixel 2, and D represents the width of the on-chip lens 203A.

21. Method of Manufacturing Pixels According to Thirteenth Embodiment

Next, a description will be given, with reference to FIGS. 47A to 47D and FIGS. 48A to 48D, of the method of manufacturing the pixels 2 according to the thirteenth embodiment.

First, as shown in FIG. 47A, the photodiodes 41 are formed on a pixel-by-pixel basis inside the semiconductor substrate 12, and the protection film 201 is formed with a prescribed thickness on the entire surface on the rear surface side of the semiconductor substrate 12. Note that although omitted in the figures, the element separation layers 68 between the photodiodes 41 and the multilevel wiring layer 66 including the plurality of pixel transistors Tr are also formed as in the embodiments described above.

Then, as shown in FIG. 47B, a photoresist 211 is deposited on the entire surface on the upper side of the protection film 201 and patterned to remain only at the pixels 2 where the on-chip lenses 74A are to be formed, and the protection film 201 is etched. By the etching, the protection film 201 is formed to have a larger thickness at the pixels 2 where the on-chip lenses 74A are to be formed than at the pixels 2 where the on-chip lenses 74A are not to be formed.

Next, as shown in FIG. 47C, after the removal of the photoresist 211, an R color filter material 212 formed at the pixels 2 where the on-chip lenses 74A are not to be formed is coated by rotation.

Then, as shown in FIG. 47D, only the desired regions of the R color filter material 212 coated by rotation are exposed. After that, as shown in FIG. 48A, the unnecessary portions of the R color filter material 212 are removed. Thus, the color filters 202 colored in R are completed at the pixels 2 where the on-chip lenses 74A are not to be formed.

Next, as shown in FIG. 48B, a G color filter material 213 formed at the pixels 2 where the on-chip lenses 74A are not to be formed is coated by rotation.

Then, as shown in FIG. 48C, only the desired regions of the G color filter material 213 coated by rotation are exposed. After that, as shown in FIG. 48D, the unnecessary portions of the G color filter material 213 are removed. Thus, the color filters 202 colored in G are completed at the pixels 2 where the on-chip lenses 74A are to be formed.

After that, the on-chip lens layer 203 and the on-chip lenses 203A are formed on the color filters 202 at the respective colors 2, whereby the pixel structure shown in FIG. 44 is completed.

22. Fourteenth Embodiment of Pixels

(Cross-Sectional Configuration View of Pixels)

FIG. 49 is a cross-sectional configuration view according to a fourteenth embodiment of the pixels 2.

Note that components corresponding to the components of FIG. 44 according to the thirteenth embodiment described above are denoted by the same symbols in FIG. 49 and only components different from the components of the pixel structure shown in FIG. 44 will be described.

In a pixel structure according to the fourteenth embodiment, a protection film 221 formed on the upper surface on the rear surface side of the semiconductor substrate 12 has the same thickness between the pixels 2 where the on-chip lenses 203A are present and the pixels 2 where the on-chip lenses 203A are absent.

Further, in the pixel structure according to the fourteenth embodiment, photosensitive transparent resin films 222 are formed between the protection film 221 and the color filters 202 colored in G at the pixels 2 where the on-chip lenses 203A are present. Like this, the steps between the pixels 2 where the on-chip lenses 203A are present and the pixels 2 where the on-chip lenses 203A are absent may be formed by any material other than the protection film 221.

23. Method of Manufacturing Pixels According to Fourteenth Embodiment

A description will be given, with reference to FIGS. 50A to 50E and FIGS. 51A to 51D, of the method of manufacturing the pixels 2 according to the fourteenth embodiment.

As shown in FIG. 50A, after the photodiodes 41 are formed on a pixel-by-pixel basis inside the semiconductor substrate 12 and the protection film 221 is formed on the entire surface on the rear surface side of the semiconductor substrate 12, a photosensitive transparent resin layer 231 is laminated with a prescribed film thickness. Note that although omitted in the figures, the element separation layers 68 between the photodiodes 41 and the multilevel wiring layer 66 including the plurality of pixel transistors Tr are also formed as in the embodiments described above.

Then, as shown in FIG. 50B, the photosensitive transparent resin layer 231 is exposed only at the pixels 2 where the on-chip lenses 203A are to be formed. As a result, as shown in FIG. 50C, the photosensitive transparent resin films 222 are formed only at the pixels 2 where the on-chip lenses 203A are to be formed.

The following steps are the same as the manufacturing steps of the pixel structure according to the thirteenth embodiment described above.

That is, as shown in FIG. 50D, an R color filter material 212 formed at the pixels 2 where the on-chip lenses 74A are not to be formed is coated by rotation.

Then, as shown in FIG. 50E, only the desired regions of the R color filter material 212 coated by rotation are exposed. After that, as shown in FIG. 51A, the unnecessary portions of the R color filter material 212 are removed. Thus, the color filters 202 colored in R are completed at the pixels 2 where the on-chip lenses 74A are not to be formed.

Next, as shown in FIG. 51B, a G color filter material 213 formed at the pixels 2 where the on-chip lenses 74A are not to be formed is coated by rotation.

Then, as shown in FIG. 51C, only the desired regions of the G color filter material 213 coated by rotation are exposed. After that, as shown in FIG. 51D, the unnecessary portions of the G color filter material 213 are removed. Thus, the color filters 202 colored in G are completed at the pixels 2 where the on-chip lenses 74A are to be formed.

After that, the on-chip lens layer 203 and the on-chip lenses 203A are formed on the color filters 202 at the respective colors 2, whereby the pixel structure shown in FIG. 49 is completed.

24. Fifteenth Embodiment of Pixels

(Cross-Sectional Configuration View of Pixels)

FIG. 52 is a cross-sectional configuration view according to a fifteenth embodiment of the pixels 2.

Note that components corresponding to the components of FIG. 49 according to the fourteenth embodiment described above are denoted by the same symbols in FIG. 52 and only components different from the components of the pixel structure shown in FIG. 49 will be described.

In a pixel structure according to the fifteenth embodiment, color filters 241 colored in G including the portions of the photosensitive transparent resin films 222 according to the fourteenth embodiment shown in FIG. 49 are formed. Color filters 241 colored in R at the pixels 2 where the on-chip lenses 203A are absent are the same as the color filters 202 colored in R according to the fourteenth embodiment shown in FIG. 49. Such a pixel structure causes a difference in spectral characteristics due to a difference in the film thickness of the color filters 241 between the pixels 2 where the on-chip lenses 203A are present and the pixels 2 where the on-chip lenses 203A are absent but has the advantage of less manufacturing steps.

In the fourteenth and fifteenth embodiments described above, the on-chip lens layer 203 is formed to heighten the pixel structure to optimize a focal distance, and the color filters 202 (241) at the pixels 2 where the on-chip lenses 203A are present are formed to be superimposed on the color filters 202 (241) at the adjacent pixels 2 where the on-chip lenses 203A are absent. Accordingly, the degradation of color mixture may be prevented in the pixel structure of the rear surface irradiation type in which the on-chip lenses larger in size than the pixels are formed for every other pixel.

The arrangement of the colors of the color filters 202 (241) is not limited to this example in the fourteenth and fifteenth embodiments described above, but the various arrangement methods shown in FIG. 4A and FIGS. 24 to 27 may be employed.

25. Application Example to Electronic Apparatuses

The application of the technology of the present disclosure is not limited to solid-state imaging devices. In other words, the technology of the present disclosure is applicable to overall electronic apparatuses having solid-state imaging devices as image capturing portions (photoelectric conversion portions) such as imaging apparatuses including digital still cameras and video cameras, mobile terminal apparatuses having imaging functions, and copiers having solid-state imaging devices as image capturing portions. The solid-state imaging devices may be of a one-chip form or a module-like form having an imaging function and having an imaging unit and a signal processing unit or an optical system packaged therein.

FIG. 53 is a block diagram showing a configuration example of an imaging apparatus serving as an electronic apparatus according to an embodiment of the present disclosure.

An imaging apparatus 300 of FIG. 53 has an optical unit 301 including a group of lenses, a solid-state imaging device (imaging device) employing the configuration of the solid-state imaging device 1 of FIG. 1, and a DSP (Digital Signal Processor) circuit 303 serving as a camera signal processing circuit. In addition, the imaging apparatus 300 has a frame memory 304, a display unit 305, a recording unit 306, an operation unit 307, and a power supply unit 308. The DSP circuit 303, the frame memory 304, the display unit 305, the recording unit 306, the operation unit 307, and the power supply unit 308 are connected to each other via a bus line 309.

The optical unit 301 captures incident light (image light) from a subject and forms the same on the imaging surface of the solid-state imaging device 302. The solid-state imaging device 302 converts the light amount of incident light formed on the imaging surface by the optical unit 301 into an electric signal on a pixel-by-pixel basis and outputs the converted electric signal as a pixel signal. As the solid-state imaging device 302, the solid-state imaging device 1 of FIG. 1, i.e., the solid-state imaging device of the rear-surface irradiation type in which the on-chip lenses larger in size than the pixels are formed for every other pixel to prevent the degradation of color mixture may be used.

The display unit 305 is made of, for example, a panel display device such as a liquid crystal panel and an organic EL (Electro Luminescence) panel and displays moving images or still images captured by the solid-state imaging device 302. The recording unit 306 records moving images or still images captured by the solid-state imaging device 302 on a recording medium such as a hard disk and a semiconductor memory.

The operation unit 307 issues an operating command for the various functions of the imaging apparatus 300 according to user's operations. The power supply unit 308 appropriately supplies various power supplies serving as power supplies for operating the DSP circuit 303, the frame memory 304, the display unit 305, the recording unit 306, and the operation unit 307 to these supply targets.

As described above, the degradation of color mixture may be prevented when the solid-state imaging device 1 described above is used as the solid-state imaging device 302. Accordingly, the high quality of captured images may be achieved even in the imaging apparatuses 300 of camera modules or the like for mobile equipment such as video cameras, digital still cameras, and mobile phones.

The example described above refers to the solid-state imaging device in which the first conductive types serve as n-types, the second conductive types serve as p-types, and the electrons serve as signal charges. However, the technology of the present disclosure may also be applied to solid-state imaging devices in which holes serve as signal charges. That is, with the first conductive types serving as p-types and the second conductive types as n-types, the respective semiconductor regions described above may be constituted of semiconductor regions having the reverse conductive types.

In addition, the application of the technology of the present disclosure is not limited to solid-state imaging devices that detect the distribution of the incident light amounts of visible light and capture the same as images, but the technology of the present disclosure is applicable to solid-state imaging devices that capture the distribution of the incident amounts of infrared rays, X-rays, or particles as images and is applicable, in a broad sense, to overall solid-state imaging devices (physical amounts distribution detection devices) such as finger print detection sensors that detect the distribution of other physical amounts such as pressure and capacitances and capture the same as images.

The embodiments of the present disclosure are not limited to the embodiments described above but may be modified in various ways insofar as they are within the scope of the present disclosure.

For example, all or some of the plurality of embodiments described above may be combined together.

Note that the effects described in the specification are only for illustration purposes and the effects of the present disclosure are not limited to them. That is, effects other than those described in the specification may be produced.

Note that the present technology may also employ the following configurations.

(1) A solid-state imaging device, including:

a plurality of pixels arranged in a matrix pattern, each of the pixels having a photoelectric conversion portion configured to photoelectrically convert light incident from a rear surface side of a semiconductor substrate; and

a plurality of on-chip lenses arranged for every other pixel, the on-chip lenses being larger in size than the pixels, in which

each of color filters at the pixels where the on-chip lenses are present has a cross-sectional shape whose upper side close to the on-chip lens is the same in width as the on-chip lens and whose lower side close to the photoelectric conversion portion is shorter than the upper side.

(2) The solid-state imaging device according to (1), in which

a film thickness at a peripheral portion of each of the color filters at the pixels where the on-chip lenses are absent is larger than a film thickness at a central portion thereof.

(3) The solid-state imaging device according to (1) or (2), in which

each of the color filters at the pixels where the on-chip lenses are absent is formed on a transparent film made of a material having high transparency.

(4) The solid-state imaging device according to (3), in which

the transparent film has a trapezoidal cross section.

(5) The solid-state imaging device according to any one of (1) to (4), in which

each of the color filters at the pixels where the on-chip lenses are present has a trapezoidal cross section.

(6) The solid-state imaging device according to any one of (1) to (5), further including

a plurality of light-shielding walls each having a triangular cross section, the light shielding walls being arranged at positions adjacent to the color filters at the pixels where the on-chip lenses are present.

(7) The solid-state imaging device according to (6), in which

each of the light-shielding walls is made of one of a low refractive index material having a lower refractive index than the color filters and a metal material.

(8) The solid-state imaging device according to any one of (1) to (7), in which

each of the color filters at the pixels where the on-chip lenses are absent has a rectangular cross section.

(9) The solid-state imaging device according to any one of (1) to (8), in which

the lower side is the same in width as the pixels.

(10) The solid-state imaging device according to any one of (1) to (9), in which

each of the color filters is formed on a flattened film.

(11) The solid-state imaging device according to any one of (1) to (10), further including

a plurality of inter-pixel light-shielding films arranged at pixel boundary portions at an interface on the rear surface side of the semiconductor substrate.

(12) The solid-state imaging device according to (6), further including

a plurality of light-shielding portions embedded between the adjacent photoelectric conversion portions with a desired depth from the rear surface side of the semiconductor substrate.

(13) The solid-state imaging device according to (12), in which

the light-shielding walls and the light-shielding portions are connected to each other at an interface on the rear surface side of the semiconductor substrate.

(14) The solid-state imaging device according to (12), in which

the light-shielding walls and the light-shielding portions are made of a same material.

(15) The solid-state imaging device according to (12), in which

both side walls of the light-shielding walls held between the color filters are slant surfaces.

(16) The solid-state imaging device according to (12), in which

the light-shielding walls are the same in height as the color filters.

(17) The solid-state imaging device according to (12), in which

the light-shielding walls are lower in height than the color filters.

(18) The solid-state imaging device according to (12), in which

each of the light-shielding walls has a trapezoidal cross section.

(19) A method of manufacturing a solid-state imaging device having a plurality of pixels arranged in a matrix pattern, each of the pixels having a photoelectric conversion portion configured to photoelectrically convert light incident from a rear surface side of a semiconductor substrate and a plurality of on-chip lenses arranged for every other pixel, the on-chip lenses being larger in size than the pixels, the method including

forming each of color filters at the pixels where the on-chip lenses are present such that the color filter has a cross-sectional shape whose upper side close to the on-chip lens is the same in width as the on-chip lens and whose lower side close to the photoelectric conversion portion is shorter than the upper side.

(20) An electronic apparatus, including

a solid-state imaging device having

• • a plurality of pixels arranged in a matrix pattern, each of the pixels having a photoelectric conversion portion configured to photoelectrically convert light incident from a rear surface side of a semiconductor substrate, and
  • a plurality of on-chip lenses arranged for every other pixel, the on-chip lenses being larger in size than the pixels, in which
  • each of color filters at the pixels where the on-chip lenses are present has a cross-sectional shape whose upper side close to the on-chip lens is the same in width as the on-chip lens and whose lower side close to the photoelectric conversion portion is shorter than the upper side.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A light detecting device, comprising:

a plurality of color filters including:

a first group of color filters configured to transmit light in a first range of wavelengths; and

a second group of color filters configured to transmit light in a second range of wavelengths different from the first range of wavelengths; and

a third group of color filters configured to transmit light in a third range of wavelengths different from the first and second ranges of wavelengths,

wherein the first group of first color filters includes a first color filter and a second color filter disposed in a first direction,

wherein the second group of color filters includes a third color filter and a fourth color filter disposed in the first direction,

wherein an area of the first color filter is different from an area of the second color filter in a plan view, and

wherein an area of the third color filter is different from an area of the fourth color filter in the plan view,

wherein the third group of color filters includes a fifth color filter and a sixth color filter disposed in the first direction,

wherein the first range of wavelengths corresponds to green light,

wherein the second range of wavelengths corresponds to blue light, and

wherein the third and fifth color filter are disposed diagonally in the plan view.

2. The light detecting device according to claim 1, wherein the plurality of color filters further include a third group of color filters configured to transmit light in a third range of wavelengths different from the first and second ranges of wavelengths.

3. The light detecting device according to claim 2, wherein the third group of color filters includes a fifth color filter and a sixth color filter disposed in the first direction.

4. The light detecting device according to claim 1, wherein the first color filter is disposed adjacent to the second color filter.

5. The light detecting device according to claim 1, wherein the third color filter is disposed adjacent to the fourth color filter.

6. The light detecting device according to claim 3 1, wherein the fifth color filter is disposed adjacent to the sixth color filter.

7. The light detecting device according to claim 3 1, wherein an area of the fifth color filter is different from an area of the sixth color filter in the plan view.

8. The light detecting device according to claim 1, wherein the first range of wavelengths corresponds to green light.

9. The light detecting device according to claim 1, wherein the second range of wavelengths corresponds to blue light.

10. The light detecting device according to claim 2 1, wherein the third range of wavelengths corresponds to red light.

11. The light detecting device according to claim 4, wherein the area of the first color filter is larger than the area of the second color filter in the plan view.

12. The light detecting device according to claim 5, wherein the area of the third color filter is larger than the area of the fourth color filter in the plan view.

13. The light detecting device according to claim 6, wherein the area of the fifth color filter is larger than the area of the sixth color filter in the plan view.

14. The light detecting device according to claim 1, wherein the first group of color filters further includes a seventh color filter and an eighth color filter disposed in the first direction.

15. The light detecting device according to claim 14, wherein the seventh color filter is disposed adjacent to the eighth color filter.

16. The light detecting device according to claim 15, wherein an area of the seventh color filter is larger than an area of the eighth color filter.

17. The light detecting device according to claim 3, wherein the third and fifth color filter are disposed diagonally in the plan view.

18. The light detecting device according to claim 3 1, wherein the second color filter is disposed between the first color filter and the third color filter in the plan view.

19. An electronic apparatus, comprising:

an optical unit;

an imaging device, wherein the imaging device receives light captured by the optical unit, the imaging device including:

a plurality of photoelectric conversion portions; and

a plurality of color filters formed over the plurality of photoelectric conversion portions, the color filters including:

a first group of color filters configured to transmit light in a first range of wavelengths; and

a second group of color filters configured to transmit light in a second range of wavelengths different from the first range of wavelengths; and

a third group of color filters, configured to transmit light in a third range of wavelengths different from the first and second ranges of wavelengths,

wherein the first group of first color filters includes a first color filter and a second color filter disposed in a first direction,

wherein the second group of color filters includes a third color filter and a fourth color filter disposed in the first direction,

wherein an area of the first color filter is different from an area of the second color filter in a plan view, and

wherein an area of the third color filter is different from an area of the fourth color filter in the plan view,

wherein the third group of color filters includes a fifth color filter and a sixth color filter disposed in the first direction,

wherein the first range of wavelengths corresponds to green light,

wherein the second range of wavelengths corresponds to blue light, and

wherein the third and fifth color filter are disposed diagonally in the plan view; and

a digital signal processing circuit that receives and process signals provided from the imaging device.

20. The electronic apparatus of claim 19, wherein the plurality of photoelectric conversion portions are photodiodes disposed in a two dimensional array.

21. A light detecting device, comprising:

a plurality of color filters including:

a first group of color filters configured to transmit light in a first range of wavelengths;

a second group of color filters configured to transmit light in a second range of wavelengths different from the first range of wavelengths; and

a third group of color filters configured to transmit light in a third range of wavelengths different from the first and second ranges of wavelengths,

wherein the first group of color filters includes:

a first color filter area of the first group of color filters; and

a second color filter area of the first group of color filters disposed adjacent to the first color filter area in a first direction,

wherein the second group of color filters includes:

a third color filter area of the second group of color filters; and

a fourth color filter area of the second group of color filters disposed adjacent to the third color filter area in the first direction,

wherein the third group of color filters includes a fifth color filter area and a sixth color filter area disposed adjacent to the fifth color filter area in the first direction,

wherein the first range of wavelengths corresponds to green light,

wherein the second range of wavelengths corresponds to blue light, and

wherein the third and fifth color filter areas are disposed diagonally in the plan view, and

wherein the third color filter area is greater than the fourth color filter area.

22. The light detecting device of claim 21, wherein the first color filter area of the first group of color filters is corresponding to a first on-chip lens.

23. The light detecting device of claim 22, wherein the second color filter area of the first group of color filters is corresponding to a second on-chip lens.

24. The light detecting device of claim 23, wherein an area of the first on-chip lens is greater than an area of the second on-chip lens.

25. The light detecting device of claim 21, wherein the third color filter area of the second group of color filters is corresponding to a third on-chip lens.

26. The light detecting device of claim 25, wherein the fourth color filter area of the second group of color filter is corresponding to a fourth on-chip lens.

27. The light detecting device of claim 26, wherein an area of the third on-chip lens is greater than an area of the fourth on-chip lens.

28. The light detecting device according to claim 21, wherein the fifth color filter area is greater than the sixth color filter area.

29. The light detecting device according to claim 21, wherein the third range of wavelengths corresponds to red light.