CN108258002B

CN108258002B - Semiconductor device and method for manufacturing the same

Info

Publication number: CN108258002B
Application number: CN201810086090.9A
Authority: CN
Inventors: 大石周; 黄晓橹
Original assignee: Huaian Imaging Device Manufacturer Corp
Current assignee: Huaian Xide Industrial Design Co ltd
Priority date: 2018-01-30
Filing date: 2018-01-30
Publication date: 2020-07-14
Anticipated expiration: 2038-01-30
Also published as: CN108258002A

Abstract

The present disclosure relates to a semiconductor device and a method of manufacturing the same. The semiconductor device includes: a substrate; a plurality of color filter elements formed on the substrate, each color filter element for allowing light of a specific wavelength to pass therethrough; and an isolation structure formed between two adjacent color filter elements for preventing crosstalk of light between the color filter elements; wherein the isolation structure comprises a light absorbing structure.

Description

Semiconductor device and method for manufacturing the same

Technical Field

The present disclosure relates to the field of semiconductors, and more particularly, to semiconductor devices and methods of manufacturing the same.

Background

The image sensor may be used to sense radiation (e.g., optical radiation, including but not limited to visible light, infrared, ultraviolet, etc.) to generate corresponding electrical signals (imaging). Image sensors are currently widely used in digital cameras, security installations, or other imaging devices.

For image sensors, imaging quality is an important performance indicator. When unwanted radiation enters the sensing region, imaging quality can be affected. In particular, if the intensity of the undesired radiation is large, for example, flare (flare) is formed, a serious adverse effect may be exerted on the image quality.

Disclosure of Invention

An object of the present disclosure is to provide a novel semiconductor device and a method of manufacturing the same, and particularly, to improving the imaging quality of an image sensor.

According to a first aspect of the present disclosure, there is provided a semiconductor device including: a substrate; a plurality of color filter elements formed on the substrate, each color filter element for allowing light of a specific wavelength to pass therethrough; and an isolation structure formed between two adjacent color filter elements for preventing crosstalk of light between the color filter elements; wherein the isolation structure comprises a light absorbing structure.

According to a second aspect of the present disclosure, there is provided a method of manufacturing a semiconductor device, the method comprising: providing a substrate; forming an isolation structure over a substrate; forming a plurality of color filter elements over a substrate, each color filter element for allowing light of a specific wavelength to pass through; wherein the isolation structure is arranged between two adjacent color filter elements for preventing crosstalk of light between the color filter elements, and the isolation structure comprises a light absorbing structure.

Other features of the present disclosure and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description, serve to explain the principles of the disclosure.

The present disclosure may be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:

fig. 1A is a schematic sectional view showing an imaging module employing an image sensor according to the related art.

Fig. 1B is a schematic sectional view showing an imaging module employing an image sensor according to the related art.

Fig. 2 is a schematic cross-sectional view illustrating a semiconductor device according to one embodiment of the present disclosure.

Fig. 3 is a schematic cross-sectional view illustrating a semiconductor device according to another embodiment of the present disclosure

Fig. 4 is a flowchart illustrating a method of manufacturing a semiconductor device according to one embodiment of the present disclosure.

Fig. 5A to 5E are schematic cross-sectional views illustrating a semiconductor device corresponding to a part of the steps of the method illustrated in fig. 4.

Fig. 6A to 6C are schematic cross-sectional views illustrating a semiconductor device corresponding to a part of the steps of the method illustrated in fig. 4.

Note that in the embodiments described below, the same reference numerals are used in common between different drawings to denote the same portions or portions having the same functions, and a repetitive description thereof will be omitted. In this specification, like reference numerals and letters are used to designate like items, and therefore, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

For convenience of understanding, the positions, sizes, ranges, and the like of the respective structures shown in the drawings and the like do not sometimes indicate actual positions, sizes, ranges, and the like. Therefore, the disclosed invention is not limited to the positions, dimensions, ranges, etc., disclosed in the drawings and the like.

Detailed Description

The inventors of the present application have recognized that conventional image sensors face greater challenges in terms of imaging quality.

Fig. 1A, 1B illustrate schematic cross-sectional views of an imaging module 100 employing an image sensor 101 according to the related art.

Image sensor 101, such as a typical backside illuminated (BSI) image sensor 101, typically has a color filter 126 disposed over each radiation sensing area (not illustrated) to selectively allow radiation of a particular wavelength to enter the corresponding radiation sensing area. As such, each radiation-sensing region may only sense radiation of a particular wavelength. Furthermore, radiation reflecting structures 124, such as metal grids, may be provided between respective adjacent color filters 126 as isolation structures to reduce possible radiation cross talk. Thus, radiation incident on the image sensor 101 may impinge not only on the color filter element 126, and thus into the radiation sensing region, but also on the radiation reflecting structure 124. Further, in the imaging module 100 employing the image sensor 101, other components disposed in the incident direction of radiation, for example, an infrared cut filter 103 may also be generally included.

Those skilled in the art will readily appreciate that the reflection of incident radiation at various interfaces in the imaging module 100 is widespread. It is noteworthy that the radiation entering the color filter element 126 by reflection may be undesired radiation. For example, as shown in fig. 1A, when light is incident at a certain angle, the radiation reflected by a certain radiation reflection structure 124 to an infrared cut filter 103 and reflected by the infrared cut filter 103 to a certain color filter 126 is not desirable for the color filter 126. In general, the undesired radiation degrades the imaging quality, especially when its intensity is large and even flares are formed.

In addition, the radiation reflecting structures 124 generally having an array-type distribution can be approximately regarded as reflective grating structures when the pitch is equivalent to the wavelength of radiation. Thus, radiation incident on the radiation reflecting structure 124 may produce diffraction effects. For example, as shown in FIG. 1B, even when light is incident in the normal direction, radiation incident on the radiation reflecting structure 124 is diffracted by the reflective grating, and the diffracted radiation has a diffraction angle θ. As a result, strong radiation (e.g., flare) may fall on the infrared cut filter 103 and be reflected into the color filter element 126, thereby having a large adverse effect on the imaging quality of the image sensor 101.

Therefore, reducing the adverse effects of reflection in the image sensor, especially eliminating flare due to the reflective diffraction effect, is of great importance for the imaging quality of the image sensor.

The inventors of the present application propose a semiconductor device and a method of manufacturing the same. In the semiconductor device (for example, an image sensor), an isolation structure of a color filter element is designed. Advantageously, using the techniques of the present disclosure can improve the imaging quality of semiconductor devices.

In addition, it will be understood by those skilled in the art that although the examples described herein are directed to image sensors, the present invention may be applied to other semiconductor devices that sense radiation.

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

Fig. 2 schematically illustrates a cross-sectional view of a semiconductor device 200 according to one embodiment of the present disclosure.

As shown in fig. 2, the semiconductor device 200 includes a substrate 202.

In addition, the semiconductor device 200 further includes a plurality of color filter elements 226 formed over the substrate 202. Each color filter element 226 is adapted to allow light of a particular wavelength to pass through.

Also, as shown in fig. 2, the semiconductor device 200 further includes an isolation structure 220 formed between two adjacent color filter elements 226 for preventing crosstalk of light between the color filter elements 226.

In various embodiments, the isolation structure 220 includes a light absorbing structure 222.

For the substrate 202, in some embodiments, examples of materials of the substrate 202 may include, but are not limited to, a unitary semiconductor material (such as silicon or germanium, etc.), a compound semiconductor material (such as silicon carbide, silicon germanium, gallium arsenide, gallium phosphide, indium arsenide, and/or indium antimonide), or a combination thereof. In other embodiments, the substrate may be a composite substrate such as a silicon-on-insulator (SOI) substrate or a silicon germanium-on-insulator (sige-on-insulator substrate). It will be understood by those skilled in the art that there is no particular limitation on the substrate 202, but may be selected according to the actual application.

In general, the color filter 226 allows light of a specific wavelength to pass through. For example, in some embodiments, a green color filter allows only green light to pass, a red color filter allows only red light to pass, and a blue color filter allows only blue light to pass. In some embodiments, the color filter element 226 may include a dye-based polymer for filtering out light of a particular frequency band. Alternatively, in some embodiments, the color filter element 226 may include a resin or other organic matrix material with color pigments.

In various embodiments, the light absorbing structure 222 may absorb light incident thereon

In one aspect, the light absorbing structure 222 can be used to isolate individual color filter elements 226, thereby preventing cross-talk of light between color filter elements 226. Since light incident on the light absorbing structure 222 is at least partially absorbed, light cannot pass directly through the light absorbing structure 222 from one color filter element 226 to another color filter element 226, but rather experiences some attenuation. Wherein the degree of attenuation is related to the absorption capacity of the light absorbing structure 222. By proper design of the light absorbing structure 222, e.g., by selection of a suitable absorbing material, light incident on the light absorbing structure 222 can be mostly absorbed and thus prevented from passing through.

In some embodiments, the light absorbing structure 222 may be formed of a narrow bandgap semiconductor material.

For semiconductor materials with a forbidden bandwidth smaller than the photon energy, the incident photon can be absorbed by exciting the valence band electron to transfer to the conduction band. For example, the wavelength range of visible light is 400nm to 700nm, and the corresponding photon energies are 3.1eV to 1.8eV, respectively. For semiconductor materials with a forbidden bandwidth less than 1.8eV, almost all visible light can be absorbed by excited valence band electron transfer to the conduction band.

Typically, in some embodiments, examples of narrow bandgap semiconductor materials forming the light absorbing structure 222 may include, but are not limited to, one or more of the following: germanium, silicon germanium or gallium arsenide.

In some embodiments, the light absorbing structure 222 may be formed of a Carbon coating (Spin-On-Carbon, SOC).

Typically, in some embodiments, the major component of the carbon coating forming the light absorbing structure 222 is a high carbon content polymer.

Additionally, in some embodiments, the light absorbing structure 222 may be a combination of color filters for different wavelengths of light.

The color filter element generally allows only certain wavelengths of light to pass through. Combining color filter elements for light of different wavelengths, the combined light absorbing structure 222 will block almost all light from passing if there is little or no intersection of the wavelength ranges of the light allowed to pass by the individual color filter elements.

In some embodiments, the combination may include stacking one on top of the other, and so forth.

For example, in some embodiments, the light absorbing structure 222 may be formed by stacking a color filter for red and a color filter for blue. The color filter for red allows mainly red light of a long wavelength to pass therethrough, and the color filter for blue allows mainly blue light of a short wavelength to pass therethrough, and therefore almost all visible light cannot pass through the light absorbing structure 222 thus stacked.

On the other hand, the light absorbing structure 222 may serve to suppress undesired optical radiation caused by reflection by the isolation structure 220. Since the light absorbing structure 222 may absorb light, the reflection of the isolation structure 220 may be reduced or even eliminated as long as the light incident to the isolation structure 220 may at least partially fall on the light absorbing structure 222. By judicious design of the isolation structures 220, e.g., the arrangement of the light absorbing structures 222 in the isolation structures 220, undesired optical radiation caused by reflection by the isolation structures 220 can be significantly reduced, or even completely eliminated.

In some embodiments of the present application, as shown in fig. 2, the isolation structure 220 includes only the light absorbing structure 222.

In this arrangement, all of the light incident on the isolation structure 220 falls on the light absorption structure 222. Advantageously, this arrangement enables to effectively avoid reflections caused by the isolation structures 220, thereby suppressing undesired optical radiation. In addition, the process steps of the arrangement mode are relatively simple, and the manufacturing cost can be effectively reduced.

For example, in some embodiments, the light absorbing structure 222 may be formed by deposition (e.g., physical vapor deposition, chemical vapor deposition, or any other suitable process) on the substrate 202 and then patterning (e.g., dry etching). However, it will be understood by those skilled in the art that the light absorbing structure 222 may be formed by any suitable process.

It will be understood by those skilled in the art that the arrangement of the light absorbing structures 222 in the isolation structure 220 is not limited thereto, but may be designed as desired. For ease of understanding, another example regarding the arrangement of the light absorbing structure 222 will be illustrated in detail later in another embodiment according to the present application.

As described above, advantageously, the isolation structure 220 including the light absorption structure 222 can not only isolate the color filter 226 to prevent crosstalk of light, but also suppress undesired light radiation caused by self-reflection. Therefore, the isolation structure 220 including the light absorbing structure 222 contributes to an improvement in image quality.

Optionally, in some embodiments, other components or layers may also have been formed in/on the substrate 202.

For example, in some embodiments, a photoelectric conversion unit 206 for sensing light may be included in the substrate 202.

As shown in fig. 2, in some embodiments, a plurality of photoelectric conversion units 206 may be disposed in the substrate 202 to sense the intensity (luminance) of incident light, respectively. In some embodiments, the photoelectric conversion unit 206 may be a doped region formed in the substrate 202 by n-type and/or p-type dopants. For example, in some embodiments, the photoelectric conversion unit 206 is an n-type doped region.

In some embodiments, for example, when the semiconductor device 200 is a back-illuminated image sensor, the photoelectric conversion unit 206 may be formed adjacent to the back surface of the substrate 202.

Furthermore, in some embodiments, a photosensitive isolation structure (not illustrated) may also be disposed between adjacent photoelectric conversion units 206.

Optionally, in some embodiments, a fixed charge layer 208 may be formed on the substrate 202 (backside), as shown in fig. 2.

In some embodiments, the fixed charge layer 208 may be used to accumulate charge. The accumulated charge is typically negative, but may be positive in some cases. When the fixed charge layer 208 has accumulated negative (positive) charges, these charges attract the positive (negative) charges in the back surface of the substrate 202 to the vicinity of the interface to form an electric dipole, thereby improving dark current. For example, in some embodiments, the fixed charge layer 208 may be formed of hypofluorite (HfO) or aluminum oxide and tantalum oxide (AlO + TaO).

Although not illustrated, other features or layers may also have been formed on/in the substrate 202, such as contact holes, underlying metal lines and vias, and other features formed in earlier processing steps, and/or interlayer dielectric layers, among others.

In some embodiments, the color filter element 226 formed on the substrate 202 (fixed charge layer 208) corresponds to the photoelectric conversion unit 206. Here, "correspond" means that the color filter element 226 and the photoelectric conversion unit 206 are arranged to at least partially overlap in a top view. For example, as shown in fig. 2, the color filter 226 is aligned with the photoelectric conversion unit 206. However, it should be understood by those skilled in the art that the arrangement of the color filter element 226 and the photoelectric conversion unit 206 is not limited to the above example.

Optionally, in some embodiments, the semiconductor device 200 may further include a microlens 228.

In some embodiments, as shown in fig. 2, the microlenses 228 can be correspondingly formed on the color filter elements 226. The microlenses 228 may be used to condense incident optical radiation in the respective photoelectric conversion units 206. It will be appreciated by those skilled in the art that the microlenses 228 can be formed of any suitable material by any suitable process.

In some embodiments, the semiconductor device 200 may optionally further include an anti-reflective layer (not illustrated).

For example, an anti-reflective layer may be formed over the color filter element 226. In some embodiments, the antireflective layer may be comprised of a dielectric material, such as silicon nitride or silicon hydroxide. The anti-reflective layer may be used to prevent the color filter 226 or microlenses 228 (if any) over the color filter 226 from reflecting the incident light, thereby further reducing the undesired optical radiation.

Fig. 3 shows a schematic cross-sectional view of a semiconductor device 300 according to another embodiment of the present disclosure. In the following, in describing embodiments according to the present invention, a detailed description will be made only for differences between the embodiments in order to simplify the description, and repeated descriptions of the same or similar parts will be omitted. Fig. 3 is mainly used to illustrate another example regarding the arrangement of the light absorption structure 222 in the isolation structure 220. For purposes of simplicity, the detailed description below will only be directed to isolation structure 220.

In some embodiments of the present application, as shown in fig. 3, the isolation structure 220 includes not only the light absorbing structure 222, but also the light reflecting structure 224. Wherein the light absorbing structure 222 is formed over the light reflecting structure 224.

According to this arrangement, light incident on the isolation structure 220 from the outside may all fall on the light absorption structure 222. Therefore, this arrangement is also effective in avoiding undesired optical radiation caused by reflection by the isolation structure 220. Furthermore, since the energy loss due to reflection can be relatively low, the provision of the light reflection structure 224 can suppress crosstalk of light between the color filter elements 226 with low loss, thereby improving the sensitivity of the semiconductor device 200 to incident light.

This arrangement thus enables reflection by the isolation structures 220 to be effectively avoided, thereby suppressing undesired light radiation, which is particularly advantageous for improving image quality in the case of sufficient illumination. Furthermore, this arrangement can also increase the sensitivity of the semiconductor device 200 to incident light, which is particularly advantageous for low-light environments. Therefore, this arrangement can also improve the dynamic range of the semiconductor device.

In some embodiments, the light reflecting structure 224 may include one or more of the following: tungsten, aluminum, silicon dioxide, or silicon nitride.

Fig. 4 is a flowchart illustrating a method of manufacturing a semiconductor device according to one embodiment of the present disclosure. Fig. 5A to 5E and fig. 6A to 6C are schematic cross-sectional views respectively showing a semiconductor device corresponding to a part of the steps of the method shown in fig. 4. The following description will be made with reference to fig. 4, fig. 5A to 5E, and fig. 6A to 6C. The same applies to the corresponding features as described above in connection with fig. 2, 3.

At step 402, a substrate 202 is provided.

At step 404, an isolation structure 220 is formed over the substrate 202 (fixed charge layer 208). Wherein the isolation structure 220 includes a light absorbing structure 222.

At step 406, color filter elements 226 are formed on the substrate 202. Each color filter element 226 is adapted to allow light of a particular wavelength to pass through.

As shown in fig. 5E, the isolation structure 220 is disposed between two adjacent color filter elements 226 for preventing crosstalk of light between the color filter elements 226.

In some embodiments, as shown in fig. 5A, a photoelectric conversion unit 206 has been formed in the provided substrate 202.

In some embodiments, the photoelectric conversion unit 206 may be a doped region formed in the substrate 202 by n-type and/or p-type dopants.

For example, in some embodiments, the photoelectric conversion unit 206 may be formed by means such as diffusion and/or ion implantation of dopants. However, it is readily understood by those skilled in the art that the present invention is not limited thereto, and other doping methods may be used to form the doped region.

In some embodiments, photosensitive isolation structures (not illustrated) may be disposed between adjacent photoelectric conversion units 206. For example, Deep Trench Isolation (DTI) techniques may be utilized. However, those skilled in the art will readily appreciate that the present invention is not so limited and other methods may be employed to form the photosensitive isolation structure.

Alternatively, in some embodiments, a fixed charge layer 208 is formed on (backside of) the provided substrate 202, as shown in fig. 5B.

As described above, the fixed charge layer 208 may be used to accumulate charges, thereby improving dark current.

In some embodiments, the fixed charge layer 208 may be formed by atomic layer deposition techniques.

In general, examples of materials of the fixed charge layer 208 may include, but are not limited to: hypofluoric acid (HfO) or aluminum oxide and tantalum oxide (AlO + TaO).

One skilled in the art will readily appreciate that other layers or components may also have been formed on the substrate 202.

In various embodiments, the isolation structures 220 may be formed by deposition (e.g., physical vapor deposition, chemical vapor deposition, or any other suitable process) and then patterning (e.g., etching) on the substrate 202. However, it will be appreciated by those skilled in the art that the isolation structures 220 may be formed by any suitable process. For example, in some embodiments, the light absorbing structures 222 in the isolation structures 220 may be obtained by combining color filter elements for different wavelengths of light. For example, a color filter element for red may be stacked with a color filter element for blue.

Preferably, the formation manner of the isolation structure 220 is designed and determined according to the arrangement manner of the light absorption structures 222 therein.

In some embodiments, the isolation structures 220 including only the light absorbing structures 222 may be formed by several sub-steps. Correspondingly, fig. 5C to 5D are schematic cross-sectional views showing semiconductor devices corresponding to these sub-steps

First, as shown in fig. 5C, an absorption spacer layer 212 is formed on the fixed charge layer 208.

In some embodiments, the absorptive isolation layer 212 may be formed by a deposition process. For example, the absorption isolation layer 212 may be formed by using physical vapor deposition, chemical vapor deposition, or any other suitable process.

In some embodiments, the absorptive isolation layer 212 may be formed of a narrow bandgap semiconductor material.

Typically, in some embodiments, examples of narrow bandgap semiconductor materials may include, but are not limited to, one or more of the following: germanium, silicon germanium or gallium arsenide.

It will be appreciated by those skilled in the art that the absorbent barrier layer 212 may also be formed of any other suitable material in any other suitable manner.

For example, in some embodiments, the absorption isolation layer 212 may also be formed by spin coating from a carbon-containing polymer. That is, the absorptive isolation layer 212 may include a carbon coating.

Subsequently, as shown in fig. 5D, the absorption isolation layer 212 may be patterned to form a light absorption structure 222. The patterning process may be accomplished using any suitable etching method known in the art, including, but not limited to, using a patterned mask (e.g., photoresist or hard mask). Any known suitable etching process may be used herein, such as wet etching, dry etching (e.g., plasma etching, etc.).

Those skilled in the art will readily appreciate that the formation of the isolation structures 220 including only the light absorbing structures 222 is not limited to the manner described above.

In some embodiments of the present application, as shown in fig. 3, the isolation structure 220 further comprises a light reflecting structure 224, wherein the light absorbing structure 222 is formed over the light reflecting structure 224.

In some embodiments, the isolation structure 220, which also includes the light reflecting structure 224, may be formed by several sub-steps. Correspondingly, fig. 6A to 6C are schematic sectional views showing the semiconductor device corresponding to these sub-steps.

First, as shown in fig. 6A, a reflective spacer layer 214 is formed on the fixed charge layer 208.

Subsequently, as shown in fig. 6B, an absorption spacer 212 is formed on the reflection spacer 214.

In some embodiments, the reflective spacer layer 214 and/or the absorptive spacer layer 212 can be formed by a deposition process. For example, it may be formed by using physical vapor deposition, chemical vapor deposition, or any other suitable process.

In some embodiments, examples of materials of the reflective isolation layer 214 may include, but are not limited to: one or more of tungsten, aluminum, silicon dioxide, silicon nitride, or combinations thereof.

It will be appreciated by those skilled in the art that the reflective spacer 214 and/or absorptive spacer 212 may also be formed in any other suitable manner.

For example, in some embodiments, the absorption isolation layer 212 may also be formed by spin coating from a carbon-containing polymer.

Subsequently, as shown in fig. 6C, a patterning process may be performed to form the isolation structure 220. The patterning process may be accomplished using any suitable etching method known in the art, including, but not limited to, using a patterned mask (e.g., photoresist or hard mask). Any known suitable etching process may be used herein, such as wet etching, dry etching (e.g., plasma etching, etc.).

In some embodiments, patterning the reflective spacer 214 and the absorptive spacer 212 may be done in a single step. Alternatively, in some embodiments, patterning the reflective spacer 214 and the absorptive spacer 212 separately may be done in separate steps.

It will be readily understood by those skilled in the art that the formation of the isolation structure 220, which also includes the light reflecting structure 224, is not limited to the manner described above.

In some embodiments, the color filter element 226 is formed corresponding to the photoelectric conversion unit 206.

Examples of materials for the color filter element 226 may include, but are not limited to: dye-based polymers, resins or other organic matrix materials with colored pigments.

It will be appreciated by those skilled in the art that the color filter element 226 may be formed in any suitable manner.

In some embodiments, a microlens 228 is optionally correspondingly formed on the color filter element 226. It will be appreciated by those skilled in the art that the microlenses 228 can be formed of any suitable material by any suitable process. In addition, the microlens 228 may be shaped and sized according to parameters such as a refractive index of a forming material.

In some embodiments, an anti-reflective layer (not illustrated) is optionally formed over the color filter element 226. The antireflective layer may be comprised of a dielectric material, such as silicon nitride or silicon hydroxide. The anti-reflective layer may be used to prevent the color filter 226 or microlenses 228 (if any) over the color filter 226 from reflecting the incident light, thereby further reducing the undesired optical radiation.

It is to be noted that the boundaries between the various steps of fabricating the semiconductor device above are merely illustrative. In actual practice, the steps can be combined arbitrarily, and even a single step can be synthesized. In addition, the execution order of the respective steps is not limited by the description order, and some steps may be omitted.

According to an aspect of the present disclosure, there is provided a semiconductor device including: a substrate; a plurality of color filter elements formed on the substrate, each color filter element for allowing light of a specific wavelength to pass therethrough; and an isolation structure formed between two adjacent color filter elements for preventing crosstalk of light between the color filter elements; wherein the isolation structure comprises a light absorbing structure.

According to one embodiment, the isolation structure further comprises a light reflecting structure, wherein the light absorbing structure is formed over the light reflecting structure.

According to one embodiment, the isolation structure comprises only light absorbing structures.

According to one embodiment, the light absorbing structure is formed from a narrow bandgap semiconductor material.

According to one embodiment, the narrow bandgap semiconductor material forming the light absorbing structure comprises one or more of: germanium, silicon germanium or gallium arsenide.

According to one embodiment, the light absorbing structure is formed by a carbon coating.

According to one embodiment, the light absorbing structure is a combination of color filter elements for light of different wavelengths.

According to one embodiment, the light absorbing structure is obtained by stacking a color filter element for red and a color filter element for blue.

According to one embodiment, the light reflecting structure comprises one or more of the following: tungsten, aluminum, silicon dioxide, or silicon nitride.

According to one embodiment, the substrate includes a photoelectric conversion unit for sensing light, and the color filter element corresponds to the photoelectric conversion unit.

According to one embodiment, the photoelectric conversion unit is formed adjacent to a back surface of the substrate, and the color filter element and the isolation structure are located on the back surface of the substrate.

According to one embodiment, the semiconductor device further includes a fixed charge layer formed over the substrate, the fixed charge layer being located under the color filter element and the isolation structure.

According to one embodiment, the semiconductor device further includes an anti-reflection layer formed over the color filter.

According to an aspect of the present disclosure, there is provided a method of manufacturing a semiconductor device, the method including: providing a substrate; forming an isolation structure over a substrate; forming a plurality of color filter elements over a substrate, each color filter element for allowing light of a specific wavelength to pass through; wherein the isolation structure is arranged between two adjacent color filter elements for preventing crosstalk of light between the color filter elements, and the isolation structure comprises a light absorbing structure.

According to one embodiment, the method further comprises forming a fixed charge layer over the substrate, the fixed charge layer underlying the color filter element and the isolation structure.

According to one embodiment, the method further comprises forming an anti-reflective layer over the color filter element.

The terms "front," "back," "top," "bottom," "over," "under," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the disclosure described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

As used herein, the word "exemplary" means "serving as an example, instance, or illustration," and not as a "model" that is to be replicated accurately. Any implementation exemplarily described herein is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, the disclosure is not limited by any expressed or implied theory presented in the preceding technical field, background, brief summary or the detailed description.

As used herein, the term "substantially" is intended to encompass any minor variation resulting from design or manufacturing imperfections, device or component tolerances, environmental influences, and/or other factors. The word "substantially" also allows for differences from a perfect or ideal situation due to parasitic effects, noise, and other practical considerations that may exist in a practical implementation.

The above description may indicate elements or nodes or features being "connected" or "coupled" together. As used herein, unless expressly stated otherwise, "connected" means that one element/node/feature is directly connected to (or directly communicates with) another element/node/feature, either electrically, mechanically, logically, or otherwise. Similarly, unless expressly stated otherwise, "coupled" means that one element/node/feature may be mechanically, electrically, logically, or otherwise joined to another element/node/feature in a direct or indirect manner to allow for interaction, even though the two features may not be directly connected. That is, coupled is intended to include both direct and indirect joining of elements or other features, including connection with one or more intermediate elements.

In addition, certain terminology may also be used in the following description for the purpose of reference only, and thus is not intended to be limiting. For example, the terms "first," "second," and other such numerical terms referring to structures or elements do not imply a sequence or order unless clearly indicated by the context.

It will be further understood that the terms "comprises/comprising," "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In the present disclosure, the term "providing" is used broadly to encompass all ways of obtaining an object, and thus "providing an object" includes, but is not limited to, "purchasing," "preparing/manufacturing," "arranging/setting," "installing/assembling," and/or "ordering" the object, and the like.

Those skilled in the art will appreciate that the boundaries between the above described operations merely illustrative. Multiple operations may be combined into a single operation, single operations may be distributed in additional operations, and operations may be performed at least partially overlapping in time. Moreover, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be altered in various other embodiments. However, other modifications, variations, and alternatives are also possible. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. The various embodiments disclosed herein may be combined in any combination without departing from the spirit and scope of the present disclosure. It will also be appreciated by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A semiconductor device, comprising:

a substrate;

a plurality of color filter elements formed on the substrate, each color filter element for allowing light of a specific wavelength to pass therethrough; and

an isolation structure formed between all adjacent two color filter elements for preventing crosstalk of light between the color filter elements;

wherein the isolation structure comprises a light absorbing structure, and

the isolation structure further comprises a light reflecting structure, wherein the light absorbing structure is formed over the light reflecting structure.

2. The semiconductor device according to claim 1, wherein:

the light absorbing structure is formed from a narrow bandgap semiconductor material.

3. The semiconductor device according to claim 2, wherein:

the narrow bandgap semiconductor material forming the light absorbing structure comprises one or more of: germanium, silicon germanium or gallium arsenide.

4. The semiconductor device according to claim 1, wherein:

the light absorbing structure is formed from a carbon coating.

5. The semiconductor device according to claim 1, wherein:

the light absorbing structure is obtained by combining color filter elements for light of different wavelengths.

6. The semiconductor device according to claim 5, wherein:

the light absorbing structure is formed by stacking a color filter for red and a color filter for blue.

7. The semiconductor device according to claim 1, wherein:

the light reflecting structure comprises one or more of the following: tungsten, aluminum, silicon dioxide, or silicon nitride.

8. The semiconductor device according to claim 1, wherein:

the substrate includes a photoelectric conversion unit for sensing light, and the color filter corresponds to the photoelectric conversion unit.

9. The semiconductor device according to claim 8, wherein:

the photoelectric conversion unit is formed adjacent to a back surface of the substrate, the color filter element and the isolation structure being located on the back surface of the substrate.

10. The semiconductor device according to claim 1, wherein:

the semiconductor device further includes a fixed charge layer formed over the substrate, the fixed charge layer being located under the color filter element and the isolation structure.

11. The semiconductor device according to claim 1, wherein:

the semiconductor device further includes an anti-reflection layer formed over the color filter element.

12. A method of manufacturing a semiconductor device, comprising:

providing a substrate;

forming an isolation structure over the substrate;

forming a plurality of color filter elements over the substrate, each color filter element for allowing light of a specific wavelength to pass through; wherein

The isolation structure is arranged between all adjacent two color filter elements for preventing crosstalk of light between the color filter elements,

the isolation structure comprises a light absorbing structure, an

13. The method of claim 12, wherein:

14. The method of claim 13, wherein:

15. The method of claim 12, wherein:

the light absorbing structure is formed from a carbon coating.

16. The method of claim 12, wherein:

17. The method of claim 16, wherein:

18. The method of claim 12, wherein:

19. The method of claim 12, wherein:

20. The method of claim 12, wherein:

the method also includes forming a fixed charge layer over the substrate, the fixed charge layer underlying the color filter element and the isolation structure.

21. The method of claim 12, wherein:

the method also includes forming an anti-reflective layer over the color filter element.