WO2008035861A1

WO2008035861A1 - A semiconductor device

Info

Publication number: WO2008035861A1
Application number: PCT/KR2007/004141
Authority: WO
Inventors: Robert Steven Hannebauer; Sang Keun Yoo
Original assignee: Lumiense Photonics Inc; Hanvision Co Ltd
Current assignee: Lumiense Photonics Inc; Hanvision Co Ltd
Priority date: 2006-09-20
Filing date: 2007-08-29
Publication date: 2008-03-27
Anticipated expiration: 2009-03-20
Also published as: KR100723457B1

Abstract

The present invention relates to a semiconductor device, and more particularly, a semiconductor device having a multi-level photodiode structure to maximize quantum efficiency for each wavelength. The semiconductor device includes a plurality of photodiode layers formed in a multi-level structure, an all-reflection layer formed under the photodiode layers, and a transistor layer formed under the all-reflection layer. Internal filter stacks respectively corresponding to wavelengths can be formed on the photodiode layers. Otherwise, external color filters such as anti-reflection coating layers or IR filters, which respectively correspond to wavelengths, can be added to the semiconductor device.

Description

A semiconductor device

[Technical Field]

The present invention relates to a semiconductor device, and more particularly, to a photoelectric conversion semiconductor device for maximizing quantum efficiency. [Background Art]

A semiconductor device which senses light and photoelectric-converts the light, such as a CCD (Charge Coupled Device) , receives light and processes the received light into an image signal. In an imaging device based on a semiconductor substrate such as a silicon substrate, light particles incident to the imaging device excite electrons in the lattice structure of the semiconductor substrate to generate free-electron-and-hole pairs. Free electrons or holes can be confined within a specific region of the device by using a CCD or CMOS Photodiode technique. The quantity of free electrons or holes is proportional to the intensity and energy of the incident light. The light particles incident to the imaging device interacts with the lattice in the semiconductor substrate with the penetration depth of the light having a probability according to the wavelength of the incident light. FIG. 1 is a characteristic diagram showing the relationship between the penetration depth and the wavelength of incident light, for example, a visible ray. In case of violet rays, all light particles react with the silicon lattice to generate electrons and holes via loss of their energies when they reach approximately 1.5 [M in the depth of a silicon substrate. When the wavelength of the incident light increases, probability that light particles react with the silicon lattice decreases. Thus, the penetration depth is increased. High-performance imaging devices include photodiodes buried in regions of a semiconductor substrate, which are located apart from the surface of the semiconductor substrate in order to prevent leakage current caused by incomplete silicon bonds at the surface of the semiconductor substrate. The photodiodes are formed in a single layer. If the photodiode layer has a specific thickness, the photodiodes especially well react to a specific wavelength of the spectrum of incident light. In other words, the photodiodes react less to wavelengths other than the specific wavelength. This can be well known from frequency response characteristic of a general imaging device .

FIG. 2 is a relative response curve with respect to wavelengths of incident light, obtained from a specific commercial imaging device. Referring to FIG. 2 the imaging device has the best quantum efficiency at approximately 800nm.

In general, a high-performance imaging device has photodiodes formed in a buried or pinned structure in order to remove kTC noise. In a buried photodiode, a P-doped region or an N-doped region surrounds the other region. In a pinned photodiode, P dopant and N dopant are offset each other so that an N-doped region is completely depleted and capacitance in the depletion region is eliminated. The size of the depletion region is affected by a doping level and a photodiode driving voltage.

In consideration of semiconductor process characteristics and circumstances in which an imaging device is used, a doping level and a voltage for driving a photodiode are restricted and the thickness of the photodiode is also restricted. Furthermore, the thickness of a pinned photodiode having excellent noise characteristic is further limited. Accordingly, it is difficult to manufacture an imaging device having perfect sensitivity for the entire spectrum range. This problem becomes serious in the case of Full frame CCD front illumination devices because the front illumination devices use a polysilicon gate that has transmission characteristic than intercepts the bluelight incident upon the device and shields those wavelengths of light from being collected. To solve this problem, backside illumination devices have been developed. FIG. 3 is a cross-sectional view of a conventional backside illumination imaging device. In this case it is not a CCD but a APS (active Pixel sensor device) this concept originated with CCDs. Referring to FIG. 3, a P-type epitaxial layer 2 is formed on a wafer 1, and a P well and an N well are formed thereon to form a photodiode layer 3. A transistor layer 4 is formed on the photodiode layer 3. In FIG. 3, reference numeral 5 denotes a connecting line between transistors. To fabricate the backside ilLumination imaging device, the backside of the wafer 1 is etched or ground away.

However, the waEer 1 requires a thickness of several IM₁ for mechanical strength as illustrated in FIG. 3, even when the present up-to-date mechanical grinding and chemical etching techniques are used to cut the backside of the wafer 1. In this case, loss of incident light occurs before the incident light reaches the photodiode layer 4 (because of the additional depth of Silicon) even though the wafer is not heavily doped. This deteriorates quantum efficiency. Moreover, the thickness of the silicon wafer is difficult to control when the silicon wafer is etched for backside illumination because there is no etch stop. Thus, production yield is decreased. Thickness error of several //m may deteriorate sensitivity at a short wavelength, that is, ultraviolet wavelength or blue wavelength. Furthermore, in case of a backside illumination imaging device, light is incident to transistor gates so that noise characteristic is deteriorated. Accordingly, a local light shielding member is required to prevent deterioration of noise characteristic. [Disclosure] [Technical problem]

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the conventional art, and a primary object of the present invention is to provide a photoelectric conversion semiconductor device for maximizing quantum efficiency for each of wavelengths.

Another object of the present invention is to provide a semiconductor device constructed in a manner that photodiodes are formed in a multi-level structure and a transistor layer is formed under the photodiodes to sense lights with multiple wavelengths through a single pixel region .

Yet another object of the present invention is to provide a semiconductor device which detects short wavelengths through an upper layer and detects long wavelengths through photodiodes in a multi- level structure to improve quantum efficiency for respective wavelengths.

A still another object of the present invention is to provide a semiconductor device fabricated in such a manner that an etch stop layer is formed on the surface of a wafer used to form a backside illumination imaging device, multilevel photodiodes and a transistor layer are formed on the etch stop layer, and the backside of the wafer is etched using the etch stop layer to easily control the thickness of the wafer and increase the yield. [Technical solution]

A semiconductor device according to an embodiment of the present invention includes pinned and buried photodiodes formed in a multi-level structure, a transistor layer which is formed under the pinned and buried photodiodes and constitutes a detection circuit, and a filter layer formed between neighboring photodiode layers.

The semiconductor device is fabricated in such a manner that a buffer oxide layer and an etch stop layer are sequentially formed on a handle wafer, photodiode layers are formed thereon in a multi-level structure, a transistor layer is formed on the photodiode layers, a pinned structure of the photodiode layers is formed, pixel-to- pixel isolation and contact processes are performed, the handle wafer is turned over, and the handle wafer is etched using the etch stop layer.

A semiconductor device according to another embodiment of the present invention includes photodiode layers formed in a multi-level structure, a transistor layer formed under the photodiode layers, and a contact for connecting the photodiode layers in parallel with the transistor layer. Image information respectively detected by the photodiode layers are combined and read by a detection circuit. A semiconductor device according to another embodiment of the present invention includes photodiode layers formed in a multi-level structure, a transistor layer formed under the photodiode layers, and a contact for respectively connecting the photodiode layers to the transistor layer. Image signals are respectively read from the photodiode layers using independent circuits and the read image signals are combined inside or outside pixels in an analog or digital manner to acquire image information. [Description of Drawings] Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a characteristic diagram showing the relationship between the penetration depth and wavelength of incident light in a semiconductor substrate;

FIG. 2 illustrates a relative response curve with respect to the wavelength of incident light, obtained from a conventional imaging device; FIG. 3 is a cross-sectional view of a conventional backside illumination imaging device; FIG. 4 is a cross-sectional view of a multi-level semiconductor device according to the present invention;

FIG. 5 is a cross-sectional view for explaining a process of fabricating the multi-level semiconductor device according to the present invention;

FIG. 6 is a cross-sectional view for explaining a buried photodiode of the multi-level semiconductor device according to the present invention;

FIG. 7 is a characteristic diagram for explaining light sensing state of a conventional imaging device;

FIG. 8 is a characteristic diagram for explaining light sensing state of the multi-level semiconductor device according to the present invention;

FIG. 9 is a cross-sectional view of a parallel connection structure of the multi-level semiconductor device according to the present invention;

FIG. 10 is a cross-sectional view of an independent circuit connection structure of the multi- level semiconductor device according to the present invention; FIG. 11 is a diagram for explaining the operation principle of a multi-level time delay integration (TDI) imaging device according to the present invention;

FIG. 12 illustrates a multi-level semiconductor device including an internal filter structure according to the present invention; and

FIG. 13 illustrates a multi-level semiconductor device including an external filter structure according to the present invention.

[Best Mode] Embodiments of the present invention will be explained in detail with reference to attached drawings.

FIG. 4 is a cross-sectional view of a semiconductor device according to the present invention. Referring to FIG. 4, a plurality of photodiode layers are formed in a multi - level structure a transistor layer to construct a backside illumination imaging device. Specifically, in figure 5 a metal layer 160, an overturned transistor layer 151, a thermal oxide layer 152, a dielectric layer 143 corresponding to an all -reflection layer, a red diode layer 141, a thermal oxide layer 142, an anti-reflection (AR) coating layer 133, a green diode layer 131, a thermal oxide layer 132, an AR coating layer 123, a blue diode layer 121, and a thermal oxide layer 122 are sequentially laminated, and an AR coating layer 113 is formed thereon. In figure 4, reference numeral 191 denotes a contact metal between the photodiode layers and the transistor layer, and 162a represents trench isolation for pixel-to-pixel isolation, which isolates neighboring pixels from each other.

A method for fabricating the aforementioned semiconductor device according to the present invention is explained with reference to FIG. 5. A buffer oxide layer 111 and an etch stop layer 112 are sequentially formed on a handle wafer 110, and a filter stack (AR) 113 is formed thereon. Subsequently, a semiconductor layer and an oxide layer for forming the semiconductor device are formed on another wafer and a process for thin layer transfer is performed to form a donor wafer. The donor wafer is turned over and bonded to the top face of the handle wafer 110. Then, a thin layer transfer process which removes the silicon layer of the donor wafer other than the oxide layer and the semiconductor layer is performed. Here, the semiconductor lεiyer is a photodiode layer and the oxide layer is used to isolate photodiodes layer from each other. According to the thin layer transfer process, a first donor thermal oxide layer 122 and a first donor transfer silicon layer (blue photodiode) 121 are formed, as illustrated in FIG. 5. Then, an AR coating layer 123 is formed on the first donor transfer silicon layer 121. Subsequently, the thin layer transfer process, the AR coating layer forming process and the filter stack forming process are repeated to sequentially form a second donor thermal oxide layer 132, a second donor transfer silicon layer (green photodiode) 131, an AR coating layer 133, a third donor thermal oxide layer 142, a third donor transfer silicon layer (red photodiode) 141, a filter stack (all reflect) 143, a fourth donor thermal oxide layer 152, and a fourth donor transfer silicon layer 151. Here, the fourth donor transfer silicon layer 151 is formed as a transistor layer. Then, a metal layer 160 for connecting the respective photodiodes to a circuit is formed on the transistor layer 151, and a solder bump 161 is formed on the metal layer 160. A pixel-to-pixel isolation structure and a contact structure of the photodiodes and the transistor layer are not shown in detail in FIG. 5 and explanations thereof are omitted.

The substrate obtained as above is tuned over and the handle wafer 110 and the buffer oxide layer 111 are removed, and then the etch stop layer 112 is removed. Consequently, the semiconductor device having the filter stack (AR) 113 at the top level thereof is obtained, as illustrated in FIG. 4. The filter stack 113 is an AR coating layer and the filter stack 143 formed on the transistor layer 151 is an all-reflection filter layer. A pinned and buried photodiode is fabricated in such a manner that trenches for contact and pixel-to-pixel isolation are formed in the above-described multi-level structure and a sidewall oxide layer 208 is formed on the sidewall of the trench, as illustrated in FIG. 6. Then, top, middle and bottom doped layers 204, 203 and 202 (P-N-P or N-P-N layer) constituting a photodiode are formed in the trenches, ion implantation is carried out such that the top and bottom doped layers 204 and 202 are connected to each other to form a side layer 209 to accomplish the pinned and buried photodiode.

As described above, the photodiode can be formed in a buried structure in the multi -level structure. In the PNP or NPN buried structure, junction depletion regions are respectively formed on and under the middle layer, that is, the P or N layer, which is called a pinned structure and is not illustrated in FIG. 5.

When the multi-level pinned and buried imaging device is arranged and a transistor detection circuit is located under the multi -level pinned and buried imaging device, as illustrated in FIG. 4, a short wavelength of incident light is mainly detected by the upper layer and a long wavelength of the incident light is detected through photodiodes over the upper and lower layers so that loss of incident light is minimized. Even when light with a narrow wavelength range is incident, high-efficiency detection can be achieved over an imaging device hciving a single photodiode layer .

For example, red light or near infrared light with a long wavelength penetrates a silicon wafer to a depth of more than several β\a from the surface of the silicon wafer, and thus it is very difficult to detect the light. Blue or purple light with a short wavelength is detected at the surface of the silicon wafer. If charges obtained by multilevel photodiodes are combined and read, detection efficiency over a wide wavelength range is maximized. FIG. 7 illustrates light sensing state of a conventional imaging device. Referring to FIG. 7, sensing efficiency is deteriorated at specific bands such as long wavelengths and short wavelengths. That is, in a sensing region (region indicated by a dotted line) , blue having a short wavelength is sensed only at the surface of a photodiode and light with a long wavelength is partially sensed to result in deterioration in the sensing efficiency.

Referring to FIG. 8, when multiple imaging device layers are arranged, incident light is uniformly sensed with high efficiency irrespective of wavelength characteristic of the incident light. That is, first and second photodiodes PDl and PD2 , first, second and third photodiodes PDl, PD2 and PD3 , and first, second, third and fourth photodiodes PDl, PD2 , PD3 and PD4 respectively sense respective wavelengths of incident light, as illustrated in FIG. 8. Accordingly, the photodiodes can sense the incident light even when the incident light has a short wavelength and the intensity of light having a long wavelength can be correctly detected.

Therefore, the multi- level imaging device illustrated in FIG. 4 can uniformly sense incident light with high efficiency irrespective of the wavelength characteristic of the incident light.

As an etch stop layer used to form a backside illumination device, a nitride layer or an oxide layer is formed on the handle wafer, as illustrated in FIG. 5, to control the thickness of the oxide layer on the silicon wafer very accurately. Accordingly, light sensing efficiency deterioration (at a short wavelength in particular) and yield reduction caused by difficulty in controlling the thickness of the silicon wafer can be solved. In an actual etching process, most part of the handle wafer is removed through mechanical grinding and a remaining part having a thickness which is difficult to mechanically control is removed by an etching technique. Image information corresponding to sensed light is read out through a method which connects a plurality of photodiodes in parallel to a single detection circuit and reads image information from the photodiodes using the single detection circuit, as illustrated in FIG. 9. Otherwise, the image information is read out through a method which respectively reads image information from a plurality of photodiodes using independent detection circuits, and then combines signals from the respective detection circuits inside or outside pixels in an analog or digital manner. Furthermore, there is a method which appropriately combines these two methods . FIG. 9 illustrates a multi- level semiconductor device including a detection circuit according to an embodiment of the present invention. Referring to FIG. 9, first, second, third and fourth photodiode layers 310, 320, 330 and 340 are formed in a multi-level structure, an all-reflection filter layer 350 is formed under the fourth photodiode layer 340, and a transistor layer 360 is formed under the all-reflection filter layer 350 to construct a multi-level semiconductor device. In the multi -level semiconductor device constructed as above, the photodiodes are formed in a buried and pinned structure as illustrated in FIG. 6, a trench is formed, and a contact 401 is formed in the trench to be connected in parallel with the four photodiode layers. That is, the multiple photodiodes are connected in parallel and image signals from the multiple photodiodes are read using a single detection circuit. Here, the detection circuit means a circuit of metal layers (not shown) of the transistor layer 360. FIG. 10 illustrates a multi-level semiconductor device including a detection circuit according to another embodiment of the present invention. Referring to FIG. 10, first, second, third and fourth photodiodes layers 310, 320, 330 and 340 are formed in a multi-level structure, an all- reflection filter layer 350 is formed under the fourth photodiode layer 340, and a transistor layer 360 is formed beneath the all-reflection filter layer 350 to construct a multi-level imaging device. Contacts 501 which respectively connect the respective photodiodes layers to the transistor layer are formed such that signals from the photodiode layers are respectively read using different detection circuits. The read signals are combined inside or outside pixels in an analog or digital manner. The detecting methods of FIGS. 9 and 10 can be appropriately mixed. In the structure of the multi-level semiconductor device illustrated in FIGS. 9 and 10, the all-reflection layer 350 can be formed on the transistor layer 360 so that a incorrect operation of a transistor or noise can be minimized by incident IR photons. Furthermore, there is no need to form a local light shielding membercomment : I'm not willing to support that statement, and thus it is easy to manufacture the multi- level semiconductor device without having technical difficulty.

The number of photodiodes included in the semiconductor device of the present invention is not limited to 1, 2, 3 or 4 and it can be reduced or increased if required.

A TDI device, which is a kind of a line scan camera, was developed to increase effective exposure when there is not sufficient light. When a line camera scans an object to acquire an image, the TDI device moves charges according to the velocity of the object or reads images scanned by the line camera at a high speed and combines the read images in an analog or a digital manner.

FIG. 11 is a diagram for explaining the operation principle of a multi-level TDI semiconductor device according to the present invention.

Referring to FIG. 11, the multi-level TDI semiconductor device includes a filter stack 300, a plurality of photodiode layers 310, 320, 330 and 340 formed in a multi-level structure beneath the filter stack 300, an all -reflection layer 350 formed under the photodiode layer 340, and a transistor layer 360 formed under the all- reflection layer 350. The photodiode layers 310, 320, 330 and 340 are connected to detection circuits of the transistor layer for respective pixels. The detection circuits are connected in parallel such that charges generated in the photodiode layers due to exposure are transferred to the next pixel and summed, and the quantity of summed charges is detected. Accordingly, charges generated due to exposure in a pixel are transferred to the next pixel and previous charges are summed up at a final output port so that the quantity of total charges is detected. A multi-level imaging device can operate in this manner. Image information of a pixel, read by a transistor, is transferred to a neighboring pixel and can be combined with image information generated due to new exposure through various methods such as an analog signal transfer method and a digital information transfer method.

Conversion of signals into digital signals and accumulation of information can be carried out in pixels, a part of a chip other than the pixels, or the outside of the chip. That is, previously detected image information is added to image information detected according to new exposure in such a manner that detection circuits are constructed for respective photodiodes and combine signals detected from the respective photodiodes, as illustrated in FIG. 10.

The TDI imaging device according to the present invention can selectively detect wavelengths according to a combination of external color filters.

FIG. 12 illustrates a multi-level semiconductor device including an internal filter structure according to the present invention. Referring to FIG. 12, the multilevel semiconductor device includes an oxide layer 370 for protecting a plurality of filter stacks 301, 302 and 303, the plurality of filter stacks 301, 302 and 303 which are formed beneath the oxide layer 370 and respectively correspond to wavelengths, a plurality of photodiode layers 310, 320, 330 and 340 formed in a multi-level structure under the filter stacks 301, 302 and 302 and divided into parts respectively corresponding to the filter stacks 301, 302 and 303, an all-reflection layer 350 formed under the photodiode layers, and a transistor layer 360 formed under the all-reflection layer 350 and divided into parts respectively corresponding to the filter stacks 301, 302 and 303 to respectively read image signals of different wavelengths. Here, the multi-level photodiode layer and the transistor layer are divided into parts respectively corresponding to the filter stacks and independent detection circuits are constructed for the respective parts of the multi-level photodiode layer and transistor layer (Refer to FIGS. 9 and 10) .

Color filters can be formed outside the semiconductor device. FIG. 13 illustrates a multi-level semiconductor device including an external filter structure according to the present invention.

Referring to FIG. 13, the semiconductor device includes an oxide layer 370 for protecting a filter stack 300, the filter stack 300 which corresponds to an AR coating layer or an IR cut filter and is formed under the oxide layer 370, a plurality of photodiode layers 310, 320, 330 and 340 formed in a multi-level structure under the filter stack 300 and divided into parts respectively corresponding to external color filters 301', 302' and 303', an all -reflection layer 350 formed under the photodiode layer 340, a transistor layer 360 formed beneath the all- reflection layer 350 and divided into parts respectively corresponding to the divided parts of the photodiode layers, and the external color filters 301' 302' and 303' which are formed on the oxide layer 370 and respectively correspond to different wavelengths. The multi-level photodiode layer and the transistor layer are divided into parts respectively corresponding to the external color filters 301', 302' and 303' and formed under the filter stack 300, and independent detection circuits respectively corresponding to the divided parts of the multi-level photodiode layer and the transistor layer are constructed. In FIG. 13, portions which divide the photodiode layers and the transistor layer are pixel-to-pixel isolation and contact regions and form parallel connection contacts for connecting the photodiode layers in parallel with the transistor layer in a single pixel or serial connection contacts for independently connecting each photodiode layer with the transistor layer in a single pixel (Refer to FIGS. 9 and 10) .

As described above, the multi-level semiconductor device according to the present invention forms a filter stack on a nitride layer and uses the filter stack as an AR coating layer or an IR cut filter. Furthermore, different color filters are arranged on the top of an imaging device to select different wavelengths. The multi-level semiconductor device according to the present invention can obtain optimized quantum efficiency for each of wavelengths. Though system complexity can be minimized when the filter stack is formed on the nitride layer, the filter stack may be formed outside the multi-level semiconductor device. In this case, a wavelength can be freely selected. However, assembling of the multi-level structure of the semiconductor device and the external filter stack must be carefully performed. Moreover, the thickness and material characteristic of the filter stack can be freely selected to optimize color filters or the focus of a system, [industrial Applicability]

As described above, the present invention can provide a semiconductor device having photodiodes formed in a multi- level structure and a transistor layer formed under the multi-level photodiodes to sense lights with multiple wavelengths. Furthermore, an imaging device using a multilevel photodiode structure according to the present invention senses short wavelengths using an upper layer and senses long wavelengths using a lower layer, and thus quantum efficiency for each of wavelengths over a wide wavelength range can be improved.

Moreover, the present invention forms an etch stop layer on a wafer which is etched when a backside illumination stack-type semiconductor device is fabricated, forms multi-level photodiodes and a transistor layer on the etch stop layer, and etches the wafer using the etch stop layer. Accordingly, the thickness of the semiconductor device can be easily controlled and production yield can be improved .

Claims

[CLAIMS]

[Claim l]

A multi- level semiconductor device which receives light and photoelectric-converts the received light, the multi-level semiconductor device comprising: first, second, third and fourth photodiode layers 310, 320, 330 and 340 for receiving light and respectively detecting the intensity of light for different wavelengths; an all-reflection filter layer 350 formed under the fourth photodiode layer 340; a transistor layer 360 formed under the all- reflection filter layer to detect information of light, detected by the photodiode layers, as an electric signal; and a contact 401 for connecting the first, second, third and fourth photodiode layers 310, 320, 330 and 340 in parallel with the transistor layer 360 for each pixel such that signals detected by the respective photodiode layers are combined in the transistor layer and detected. [Claim 2]

A multi -level semiconductor device which receives light and photoelectric-converts the received light, the multi-level semiconductor device comprising: first, second, third and fourth photodiode layers 310, 320, 330 and 340 for receiving light and respectively detecting the intensity of light for different wavelengths; an all-reflection filter layer 350 formed under the fourth photodiode layer 340; a transistor layer 360 formed under the all- reflection filter layer to detect information of light, detected by the photodiode layers, as an electric signal; and a contact 501 for respectively connecting the first, second, third and fourth photodiode layers 310, 320, 330 and 340 to transistor layer 360 such that a signal sensed by each photodiode layer is independently detected in the transistor layer. [Claim 3l

The multi- level semiconductor device according to claim 1 or 2 , further comprising an anti-reflection (AR) coating layer formed between neighboring photodiode layers. [Claim 4]

A multi-level semiconductor device which receives light and photoelectric-converts the received light, the multi -level semiconductor device comprising: an oxide layer 370 for protecting a plurality of filter stacks 301, 302 and 303 formed therebeneath; the plurality of filter stacks 301, 302 and 303 which are formed under the oxide layer 370 and respectively correspond to wavelengths; a plurality of photodiode layers 310, 320, 330 and 340 formed in a multi-level structure under the filter stacks 301, 302 and 303 and divided into parts respectively corresponding to the filter stacks 301, 302 and 303; a filter layer 311, 321 and 331 formed between neighboring photodiode layers; an all -reflection layer 350 formed under the photodiode layer 340; and a transistor layer 360 formed under the all- reflection layer 350 and divided into parts respectively corresponding to the divided parts of the photodiode layers. [Claim 5]

A multi -level semiconductor device which receives light and photoelectric-converts the received light, the multi -level semiconductor device comprising: an oxide layer 370 for protecting a filter stack 300; the filter stack 300 which corresponds to an AR coating layer or an IR cut filter and is formed under the oxide layer 370; a plurality of photodiode layers 310, 320, 330 and 340 formed in a multi-level structure under the filter stack 300 and divided into parts respectively corresponding to a plurality of external color filters 301', 302' and 303' ; a filter layer 311, 321 and 331 formed between neighboring photodiode layers; an all-reflection layer 350 formed under the photodiode layer 340; a transistor layer 360 formed under the all- reflection layer 350 and divided into parts respectively corresponding to the divided parts of the photodiode layers; and the external color filters 301', 302' and 303' which is formed on the oxide layer 370 and respectively correspond to wavelengths.

[Claim δ] The multi-level semiconductor device according to claim 4 or 5, further comprising a parallel connection contact for connecting the first, second, third and fourth photodiode layers 310, 320, 330 and 340 in parallel with the transistor layer 360 for each pixel such that signals detected by the respective photodiode layers are combined in the transistor layer and detected. [Claim 7]

The multi-level semiconductor device according to claim 4 or 5, further comprising a serial connection contact for respectively connecting the first, second, third and fourth photodiode layers 310, 320, 330 and 340 to transistor layer 360 such that a signal sensed by each photodiode layer is independently detected in the transistor layer. [Claim 8]

The multi -level semiconductor device according to claim 4 or 5, wherein the serial connection contact for respectively connecting the first, second, third and fourth photodiode layers 310, 320, 330 and 340 to the transistor layer 360 and the parallel connection contact for connecting the first, second, third and fourth photodiode layers 310, 320, 330 and 340 in parallel with the transistor layer 360 for each pixel are selectively applied to each pixel, and the serial connection contact and the parallel connection contact are combined and applied in the device.