CN107068698B - Image sensor adopting quantum dot film and preparation method - Google Patents
Image sensor adopting quantum dot film and preparation method Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title abstract description 4
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 56
- 229910052782 aluminium Inorganic materials 0.000 claims description 48
- 238000000034 method Methods 0.000 claims description 25
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 23
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- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 8
- 239000010409 thin film Substances 0.000 claims description 6
- 238000000059 patterning Methods 0.000 claims description 5
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- 206010034960 Photophobia Diseases 0.000 abstract description 3
- 238000003384 imaging method Methods 0.000 abstract description 3
- 208000013469 light sensitivity Diseases 0.000 abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 10
- 238000005229 chemical vapour deposition Methods 0.000 description 6
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- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 3
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14636—Interconnect structures
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/1462—Coatings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14685—Process for coatings or optical elements
Abstract
The invention provides an image sensor adopting a quantum dot film and a preparation method thereof, wherein the image sensor comprises: a bottom isolation layer is arranged on the surface of the substrate; the N isolation layers are positioned on the bottom isolation layer, and the bottoms of the metal interconnection lines of the adjacent upper isolation layers are in contact with the top of the metal contact hole of the lower isolation layer; the N +1 th isolation layer is positioned on the nth isolation layer, and the N +1 th metal interconnection line penetrates through the N +1 th isolation layer; the bottom of the (N + 1) th layer of metal interconnection line is in one-to-one correspondence with and contacts with the top of the N layer of metal contact hole; a metal electrode is arranged on the top of the (N + 1) th layer of metal interconnection line; and quantum dot films are covered on the surfaces of the metal electrode and the exposed surface of the (N + 1) th isolation layer. The image sensor has stronger light sensitivity, larger dynamic range and more optimized imaging stability.
Description
Technical Field
The invention relates to the technical field of image sensors, in particular to an image sensor adopting a quantum dot film and a preparation method thereof.
Background
An image sensor refers to a device that converts an optical signal into an electrical signal. The CCD image sensor and the CMOS image sensor are mainly widely applied at present.
Quantum dots (quantum dots) are quasi-zero-dimensional nanocrystals, composed of a small number of atoms, generally spherical or quasi-spherical in morphology, made of semiconductor materials (usually composed of elements II B-VI B or IIIB-VB) and stable nanoparticles with a diameter of 2-20 nm. The screen can emit light under specific wavelength, is easier to calibrate in production by adopting the quantum dot technology, has more accurate color expression and has obvious advantages in the aspect of color saturation. Therefore, the quantum thin film sensor prepared by applying the quantum dots in the sensor has lighter and thinner volume, stronger light sensitivity, larger dynamic range and optimized imaging stability.
Since the conventional sensor increases the resolution by making the pixels smaller, this means that each pixel is less sensitive to light, thereby reducing the image quality, while in contrast, the quantum dot film is coated under the convex lens, and the characteristic closer to the lens makes it possible to capture light more sufficiently, thereby effectively improving the lens performance. The new technology creates a sensor that can collect twice as much light as the conventional sensor chip and convert it into an electrical signal with twice as much efficiency, while its production cost is low. After the quantum dot film is used, the thickness and the volume of the camera can be reduced on one hand, and the low-light shooting performance of the image sensor and the dynamic range of images and the like can be greatly improved on the other hand.
Disclosure of Invention
In order to overcome the above problems, the present invention aims to provide an image sensor using a quantum dot thin film for photoelectric conversion and a method for manufacturing the same, thereby improving the performance of the image sensor.
In order to achieve the above object, the present invention provides an image sensor comprising:
the device comprises a substrate, wherein a bottom isolation layer is arranged on the surface of the substrate;
n layers of isolation layers are positioned on the bottom isolation layer, wherein each layer of isolation layer is provided with a metal interconnection line and a metal contact hole positioned on the metal interconnection line; in each layer of isolation layer, the metal interconnection line is in contact with the isolation layer below the metal interconnection line, and the bottom of each metal contact hole corresponds to and is in contact with the top of the metal interconnection line of the corresponding layer one by one; the top of the metal contact hole is flush with the top of the isolation layer of the corresponding layer; the bottom of the metal interconnection line of the adjacent upper isolation layer is contacted with the top of the metal contact hole of the lower isolation layer; n is an integer and N is not less than 1;
the N +1 th isolation layer is positioned on the nth isolation layer, and the N +1 th metal interconnection line penetrates through the N +1 th isolation layer; the bottom of the (N + 1) th layer of metal interconnection line is in one-to-one correspondence with and contacts with the top of the N layer of metal contact hole;
a metal electrode is arranged on the top of the (N + 1) th layer of metal interconnection line;
and quantum dot films are covered on the surfaces of the metal electrode and the exposed surface of the (N + 1) th isolation layer.
Preferably, an inter-pixel isolation structure is further disposed at a boundary between adjacent pixels of the N +1 th isolation layer.
Preferably, the height of the metal interconnection line is 0.4-0.5 micrometers, the height of the metal contact hole is 0.4-0.5 micrometers, and the thickness of one isolation layer in the N isolation layers is 0.5-1 micrometer.
Preferably, in the N +1 isolation layers, a silicon nitride layer is further disposed between each isolation layer.
Preferably, the height of the N +1 th isolation layer is 0.5-0.6 microns.
Preferably, a pad structure is further arranged on the N +1 layer of metal interconnection lines around the quantum dot film; the pad structure and the (N + 1) th isolation layer are integral.
In order to achieve the above object, the present invention provides a method for manufacturing an image sensor, comprising:
step 01: providing a substrate; forming a bottom isolation layer on the surface of the substrate;
step 02: forming a first layer of metal aluminum on the bottom isolation layer, and patterning the first layer of metal aluminum to form a first layer of metal interconnection lines;
step 03: forming a first layer of isolation layer on the first layer of metal interconnection line and the exposed bottom isolation layer; the top of the first isolation layer is higher than the top of the first metal interconnection line;
step 04: etching a first layer of contact holes in the first layer of isolation layer corresponding to the first layer of metal interconnection lines;
step 05: filling metal tungsten in the first layer of contact holes so as to form first layer of metal contact holes;
step 06: forming a second layer of metal aluminum on the top of the first layer of metal contact hole and the surface of the first layer of isolation layer, and repeating the step 02 to the step 05K times until N layers of isolation layers and metal interconnection lines and metal contact holes of corresponding layers are formed; wherein K is an integer and is not less than 0; n is an integer and N is not less than 1; and K +1 ═ N;
step 07: forming an N +1 th layer of metal aluminum on the N layer of isolation layer and the N layer of metal contact hole, and patterning the N +1 th layer of metal aluminum to form an N +1 th layer of metal interconnection line;
step 08: covering a layer of N +1 isolation layer on the surface of the N +1 layer of metal interconnection line and the surface of the N layer of isolation layer, and flattening the top of the N +1 layer of isolation layer;
step 09: forming a metal electrode on the top of the (N + 1) th layer of metal interconnection line;
step 10: covering a quantum dot film on the surface of the metal electrode and the exposed surface of the (N + 1) th isolation layer; the top of the planarized (N + 1) th isolation layer is still higher than that of the (N + 1) th metal interconnection line.
Preferably, in the step 07, after the N +1 th metal interconnection line is formed, a silicon nitride layer covers the surface of the N +1 th metal interconnection line and the exposed surface of the nth isolation layer.
Preferably, after the step 08 and before the step 09, the method comprises the following steps: defining a pad structure region and a non-pad structure region in the (N + 1) th isolation layer; etching a pad structure in the (N + 1) th isolation layer on the (N + 1) th metal interconnection line corresponding to the pad structure region; while etching the pad structure, reserving a second layer of isolation layer corresponding to the boundary of adjacent pixels so as to form an inter-pixel isolation structure;
the step 10 specifically comprises: and covering a quantum dot film on the surface of the metal electrode in the non-pad structure region and the surface of the exposed N +1 th isolation layer.
Preferably, in the step 03, the height of the top of the first isolation layer higher than the top of the first metal interconnection line is set to be equal to the height of the first contact hole;
in the step 08, the height of the top of the planarized (N + 1) th isolation layer, which is higher than the top of the (N + 1) th metal interconnection line, is set to be equal to the height of the pad structure.
The quantum thin film sensor has stronger light sensitivity, larger dynamic range and more optimized imaging stability, and in addition, the quantum dot thin film is adopted for absorbing and converting light, so that high-quality output images can be obtained in the design of small-size pixels.
Drawings
FIG. 1 is a schematic structural diagram of an image sensor according to a preferred embodiment of the present invention
FIG. 2 is a flow chart illustrating a method for fabricating an image sensor according to a preferred embodiment of the invention
FIGS. 3 to 15 are schematic diagrams illustrating steps of a method for fabricating an image sensor according to a preferred embodiment of the invention
Detailed Description
In order to make the contents of the present invention more comprehensible, the present invention is further described below with reference to the accompanying drawings. The invention is of course not limited to this particular embodiment, and general alternatives known to those skilled in the art are also covered by the scope of the invention.
The image sensor of the present invention includes: the device comprises a substrate, wherein a bottom isolation layer is arranged on the surface of the substrate; n layers of isolation layers are positioned on the bottom isolation layer, wherein each layer of isolation layer is provided with a metal interconnection line and a metal contact hole positioned on the metal interconnection line; in each layer of isolation layer, the metal interconnection line is in contact with the isolation layer below the metal interconnection line, and the bottom of each metal contact hole corresponds to and is in contact with the top of the metal interconnection line of the corresponding layer one by one; the top of the metal contact hole is flush with the top of the isolation layer of the corresponding layer; the bottom of the metal interconnection line of the adjacent upper isolation layer is contacted with the top of the metal contact hole of the lower isolation layer; n is an integer and N is not less than 1; the N +1 th isolation layer is positioned on the nth isolation layer, and the N +1 th metal interconnection line penetrates through the N +1 th isolation layer; the bottom of the (N + 1) th layer of metal interconnection line is in one-to-one correspondence with and contacts with the top of the N layer of metal contact hole; a metal electrode is arranged on the top of the (N + 1) th layer of metal interconnection line; the surface of the metal electrode and the surface of the exposed (N + 1) th isolation layer are covered with quantum dot films; and a pad opening is arranged on the (N + 1) th layer of metal interconnection line in the edge area of the (N + 1) th layer of isolation layer.
The present invention will be described in further detail with reference to the accompanying drawings 1 to 15 and specific embodiments. It should be noted that the drawings are in a simplified form and are not to precise scale, and are only used for conveniently and clearly achieving the purpose of assisting in describing the embodiment.
Referring to fig. 1, the image sensor using quantum dot thin film for photoelectric conversion in the present embodiment is illustrated by having two isolation layers, but this is not intended to limit the scope of the N +1 isolation layers of the present invention, where N is an integer and N ≧ 1. In this embodiment, the metal interconnection line is an aluminum interconnection line, and the metal contact hole is a tungsten contact hole.
A substrate 1, wherein a bottom isolation layer 2 is arranged on the surface of the substrate 1; specifically, the substrate 1 may be, but is not limited to, an N-type or P-type double-side polished silicon wafer. The material of the bottom isolation layer 2 may be silicon oxide, the silicon oxide of the bottom isolation layer 2 may grow in a thermal growth manner but is not limited to a thermal growth manner, and may also grow by a chemical vapor deposition method, and the thickness of the silicon oxide of the bottom isolation layer 2 may be but is not limited to 0.5-1 micron.
The first-layer isolation layer 4 is positioned on the bottom isolation layer 2, wherein a first-layer aluminum interconnection line 3 and a first-layer tungsten contact hole positioned on the first-layer aluminum interconnection line 3 are arranged in the first-layer isolation layer 4, and the first tungsten contact hole is formed by a buffer layer 5 and tungsten metal 6 which are positioned in the first tungsten contact hole; in the first-layer isolation layer 4, the bottom of each aluminum interconnection line 3 is in contact with the bottom isolation layer 2, and the bottom of each first-layer tungsten contact hole is in one-to-one correspondence with and in contact with the top of the corresponding first-layer aluminum interconnection line 3; the top of the first layer of tungsten contact hole is flush with the top of the first layer of isolating layer 4; preferably, the height of the first layer of aluminum interconnection line 3 is 0.4-0.5 micrometer, the height of the first layer of tungsten contact hole is 0.4-0.5 micrometer, and the thickness of the first layer of isolation layer 4 is 0.5-1 micrometer; in the other N isolation layers, one of the N isolation layers has a thickness of 0.5 to 1 μm. The buffer layer 5 is formed by compounding a titanium layer and a titanium nitride layer, wherein the thickness of the titanium layer is 0.02-0.04 micrometer, and the thickness of the titanium nitride layer is 0.02-0.04 micrometer.
A second isolation layer 8 'positioned on the first isolation layer 4, wherein a second layer of aluminum interconnection lines 7 are arranged in the second isolation layer 8' in a penetrating manner; the bottom of the second layer of aluminum interconnection line 7 is in one-to-one correspondence with and contacts with the top of the first layer of tungsten contact hole; the height of the second layer isolation layer 8' in the non-pad area can be 0.5-0.6 microns.
A silicon nitride layer (not shown) is also arranged on the surface of the first layer of isolation layer 4 and the second layer of aluminum interconnection line 7 for isolating the first layer of tungsten contact holes from the second layer of aluminum interconnection line 7.
A metal electrode 9 is arranged at the top of the second layer of aluminum interconnection line 7;
the surface of the metal electrode 9 in the non-pad area and the surface of the exposed second isolation layer 8' are covered with a quantum dot film 10;
a pad structure 8 is provided on the second layer of aluminum interconnect lines around the quantum dot film 10, with a pad opening provided in the area of the pad structure 8. Here, the pad structure 8 and the second layer isolation layer 8' are integral. In this embodiment, there are a plurality of pixels on the substrate 1, and an isolation structure 11 is further disposed at a boundary between adjacent pixels of the second isolation layer 8'. The isolation structure 11, the pad structure 8 and the second isolation layer 8' may be integrally formed.
It should be noted that, in this embodiment, an image sensor with two isolation layers is taken as an example for description, but in other embodiments of the present invention, an image sensor structure with three or more isolation layers is further provided, and for the description of the three or more isolation layers and the aluminum interconnection lines and the tungsten contact holes of the corresponding layers, reference may be made to the description of the two isolation layers and the corresponding aluminum interconnection lines and tungsten contact holes of this embodiment, which is not described herein again.
Next, a method for manufacturing the image sensor of the present embodiment is described in detail, with reference to fig. 2, including:
step 01: referring to fig. 3, a substrate 1 is provided; forming a bottom isolation layer 2 on the surface of the substrate 1;
specifically, the substrate 1 may be, but is not limited to, an N-type or P-type double-side polished silicon wafer. The material of the bottom isolation layer 2 may be silicon oxide, the silicon oxide of the bottom isolation layer 2 may grow in a thermal growth manner but is not limited to a thermal growth manner, and may also grow by a chemical vapor deposition method, and the thickness of the silicon oxide of the bottom isolation layer 2 may be but is not limited to 0.5-1 micron.
Step 02: referring to fig. 4, a first layer of aluminum metal is formed on the bottom isolation layer 2, and the first layer of aluminum metal is patterned to form a first layer of aluminum interconnection lines 3;
in particular, the first layer of metallic aluminum may be deposited, but is not limited to, using a physical vapor deposition method. Then, the first layer of aluminum metal can be etched by, but not limited to, photolithography and anisotropic dry etching processes, and after the residual photoresist is removed, the first layer of aluminum interconnection line 3 is formed.
Step 03: referring to fig. 5, a first layer of isolation layer 4 is formed on the first layer of aluminum interconnect lines 3 and the exposed bottom isolation layer 2; specifically, the first isolation layer 4 may be deposited by, but not limited to, a chemical vapor deposition method, the material of the first isolation layer 4 may be silicon dioxide, the thickness of the first isolation layer 4 may be 0.5 to 1 micrometer, and a chemical mechanical polishing process is used to planarize the top of the first isolation layer 4. Here, the top of the first layer of isolation layer 4 is higher than the top of the first layer of aluminum interconnect; the height of the top of the first-layer isolation layer 4 higher than the top of the first-layer aluminum interconnection line 3 is set to be equal to the height of a first contact hole formed later.
Step 04: referring to fig. 6, a first layer of contact holes is etched in the first layer of isolation layer 4 corresponding to the first layer of aluminum interconnection lines 3;
specifically, the first layer isolation layer 4 may be etched by, but not limited to, photolithography and an anisotropic dry etching process, so that a first layer contact hole is etched in the first layer isolation layer 4 and corresponding to each first layer aluminum interconnection line 3.
Step 05: referring to fig. 7 to 8, a first layer of contact holes is filled with tungsten 6 to form a first layer of contact holes;
specifically, referring to fig. 7, first, a buffer layer 5 may be deposited on the bottom and the sidewall of the first contact hole and the surface of the first isolation layer 4 by, but not limited to, a physical vapor deposition process, and then, referring to fig. 8, a metal tungsten 6 may be deposited on the buffer layer 5 by, but not limited to, a chemical vapor deposition method, and the metal tungsten 6 fills the first contact hole; finally, the buffer layer 5 and the metal tungsten 6 on the surface of the first isolation layer 4 can be ground away by, but not limited to, a chemical mechanical polishing process, so as to form a first layer of tungsten contact holes.
Step 06: forming a second layer of metal aluminum on the top of the first layer of tungsten contact hole and the surface of the first layer of isolation layer, and repeating the step 02 to the step 05K times until forming N layers of isolation layers and aluminum interconnection lines and tungsten contact holes of corresponding layers; wherein K is an integer and is not less than 0; n is an integer and N is not less than 1; and K +1 ═ N;
specifically, since the image sensor of the present embodiment has only two isolation layers, K is 0 and N is 1, i.e., the steps 02 to 05 do not need to be repeated.
Step 07: forming an N +1 th layer of metal aluminum on the N layer of isolation layer and the N layer of tungsten contact hole, and patterning the N +1 th layer of metal aluminum to form an N +1 th layer of aluminum interconnection line;
specifically, referring to fig. 9, a second layer of aluminum metal 7' may be deposited on the top of the first layer of tungsten contact hole and the surface of the first layer of isolation layer 4 by, but not limited to, physical vapor deposition. Here, the height of the second layer of metallic aluminum 7' is slightly higher than the height of the first layer of metallic aluminum 4. Then, referring to fig. 10, the second layer of aluminum interconnect 7 may be formed by, but not limited to, etching the second layer of aluminum metal 7' by using photolithography and anisotropic dry etching processes, and removing the residual photoresist.
In the present embodiment, after the second layer of aluminum interconnection lines 7 are formed, a silicon nitride layer (not shown) may be further coated on the surfaces of the second layer of aluminum interconnection lines 7 and the exposed surfaces of the first layer of isolation layer 4 by, but not limited to, chemical vapor deposition. The thickness of the silicon nitride layer may be 0.05 to 0.1 μm.
Step 08: covering a layer of (N + 1) th isolation layer on the surface of the (N + 1) th aluminum interconnection line and the surface of the nth isolation layer, and flattening the top of the (N + 1) th isolation layer;
specifically, referring to fig. 11, a second isolation layer 8' may be deposited on the surface of the silicon nitride layer by, but not limited to, a chemical vapor deposition method, the material of the second isolation layer 8' may be silicon dioxide, and the thickness of the second isolation layer 8' may be 0.8 to 1 μm.
Here, the top of the planarized second-layer isolation layer 8 'is higher than the top of the second-layer aluminum interconnection line 7, and the height of the top of the planarized second-layer isolation layer 8' higher than the top of the second-layer aluminum interconnection line 7 is equal to the height of the pad structure.
After step 08, and before step 09, further comprising: defining a pad structure region and a non-pad structure region in the (N + 1) th isolation layer; etching a pad structure in the (N + 1) th isolation layer on the (N + 1) th metal interconnection line corresponding to the pad structure region;
specifically, referring to fig. 12, in the defined soldering structure region, the opening of the pad structure 8 may be etched in the second isolation layer 8 'on the second aluminum interconnection line 7 by, but not limited to, photolithography and anisotropic dry etching processes, and the second isolation layer 8' corresponding to the boundary of the adjacent pixel is remained while the opening of the pad structure 8 is etched, so as to form the inter-pixel isolation structure 11.
Step 09: forming a metal electrode on the top of the (N + 1) th layer of aluminum interconnection line;
specifically, a metal electrode is formed on the top of the second layer of aluminum interconnection line in the non-pad structure area; referring to fig. 13, a metal electrode 9 is formed on the top of the second layer of aluminum interconnection line 7, the surface of the second layer of isolation layer 8', the surface and sidewalls of the pad structure 8, and the exposed surface and sidewalls of the isolation structure 11, and the material of the metal electrode 9 may be titanium nitride. The metal electrode 9 can be deposited by, but not limited to, physical vapor deposition, and the thickness of the metal electrode 9 can be 0.05 to 0.2 micrometers, preferably 0.1 micrometer. Then, referring to fig. 14, the metal electrode 9 outside the top of the second layer of aluminum interconnection line 7 may be etched and removed by, but not limited to, photolithography and anisotropic dry etching processes, the metal electrode 9 on the top of the second layer of aluminum interconnection line 7 is remained, that is, the electrode in the non-pad structure region is remained, and the photoresist residue is removed.
Step 10: and covering a quantum dot film on the surface of the metal electrode and the surface of the exposed N +1 th isolation layer.
Specifically, referring to fig. 15, a quantum dot film is covered on the surface of the metal electrode in the non-pad structure region and the surface of the exposed N +1 th isolation layer; the surface of the metal electrode 9 and the surface of the exposed second isolation layer 8' can be covered with a quantum dot film 10 by a spin coating method.
It should be noted that, in the present embodiment, a method for preparing two isolation layers is described, but in other embodiments of the present invention, a method for repeating steps 02 to 05 in an image sensor with three or more isolation layers may be adopted, and details are not described here.
Although the present invention has been described with reference to preferred embodiments, it is to be understood that the present invention is not limited to the disclosed embodiments, but rather, may be embodied in many different forms and modifications without departing from the spirit and scope of the present invention as defined by the appended claims.
Claims (10)
1. An image sensor, comprising:
the device comprises a substrate, wherein a bottom isolation layer is arranged on the surface of the substrate;
n layers of isolation layers are positioned on the bottom isolation layer, wherein each layer of isolation layer is provided with a metal interconnection line and a metal contact hole positioned on the metal interconnection line; in each layer of isolation layer, the metal interconnection line is in contact with the isolation layer below the metal interconnection line, and the bottom of each metal contact hole corresponds to and is in contact with the top of the metal interconnection line of the corresponding layer one by one; the top of the metal contact hole is flush with the top of the isolation layer of the corresponding layer; the bottom of the metal interconnection line of the adjacent upper isolation layer is contacted with the top of the metal contact hole of the lower isolation layer; n is an integer and N is not less than 1;
the N +1 th isolation layer is positioned on the nth isolation layer, and the N +1 th metal interconnection line penetrates through the N +1 th isolation layer; the bottom of the (N + 1) th layer of metal interconnection line is in one-to-one correspondence with and contacts with the top of the N layer of metal contact hole;
a metal electrode is arranged on the top of the (N + 1) th layer of metal interconnection line; the number of metal interconnection lines in each pixel, which are positioned in the same isolation layer, is more than 1; and
and quantum dot films are covered on the surfaces of the metal electrode and the exposed surface of the (N + 1) th isolation layer.
2. The image sensor of claim 1, wherein an inter-pixel isolation structure is further disposed at a boundary between adjacent pixels of the N +1 th isolation layer.
3. The image sensor as claimed in claim 1, wherein the metal interconnection line has a height of 0.4 to 0.5 μm, the metal contact hole has a height of 0.4 to 0.5 μm, and the N isolation layers have a thickness of 0.5 to 1 μm.
4. The image sensor of claim 1, wherein the N +1 isolation layers further have a silicon nitride layer disposed between each isolation layer.
5. The image sensor as claimed in claim 1, wherein the height of the N +1 th isolation layer is 0.5 to 0.6 μm.
6. The image sensor of claim 1, wherein a pad structure is further disposed on the N +1 th layer of metal interconnection lines around the quantum dot thin film; the pad structure and the (N + 1) th isolation layer are integral.
7. A method of manufacturing an image sensor, comprising:
step 01: providing a substrate; forming a bottom isolation layer on the surface of the substrate;
step 02: forming a first layer of metal aluminum on the bottom isolation layer, and patterning the first layer of metal aluminum to form a first layer of metal interconnection lines; the number of the first layer of metal interconnection lines in each pixel is more than 1;
step 03: forming a first layer of isolation layer on the first layer of metal interconnection line and the exposed bottom isolation layer; the top of the first isolation layer is higher than the top of the first metal interconnection line;
step 04: etching a first layer of contact holes in the first layer of isolation layer corresponding to the first layer of metal interconnection lines;
step 05: filling metal tungsten in the first layer of contact holes so as to form first layer of metal contact holes;
step 06: forming a second layer of metal aluminum on the top of the first layer of metal contact hole and the surface of the first layer of isolation layer, and repeating the step 02 to the step 05K times until N layers of isolation layers and metal interconnection lines and metal contact holes of corresponding layers are formed; wherein K is an integer and is not less than 0; n is an integer and N is not less than 1; and K +1 ═ N;
step 07: forming an N +1 th layer of metal aluminum on the N layer of isolation layer and the N layer of metal contact hole, and patterning the N +1 th layer of metal aluminum to form an N +1 th layer of metal interconnection line;
step 08: covering a layer of N +1 isolation layer on the surface of the N +1 layer of metal interconnection line and the surface of the N layer of isolation layer, and flattening the top of the N +1 layer of isolation layer;
step 09: forming a metal electrode on the top of the (N + 1) th layer of metal interconnection line;
step 10: covering a quantum dot film on the surface of the metal electrode and the exposed surface of the (N + 1) th isolation layer; the top of the planarized (N + 1) th isolation layer is still higher than that of the (N + 1) th metal interconnection line.
8. The method for manufacturing the image sensor according to claim 7, wherein in the step 07, after the N +1 th metal interconnection line is formed, a silicon nitride layer is covered on the N +1 th metal interconnection line and the exposed surface of the N-th isolation layer.
9. The method for manufacturing an image sensor according to claim 7, wherein after the step 08 and before the step 09, the method comprises: defining a pad structure region and a non-pad structure region in the (N + 1) th isolation layer; etching a pad structure in the (N + 1) th isolation layer on the (N + 1) th metal interconnection line corresponding to the pad structure region; while etching the pad structure, reserving a second layer of isolation layer corresponding to the boundary of adjacent pixels so as to form an inter-pixel isolation structure;
the step 10 specifically comprises: and covering a quantum dot film on the surface of the metal electrode in the non-pad structure region and the surface of the exposed N +1 th isolation layer.
10. The method for manufacturing the image sensor according to claim 7, wherein in the step 03, the height of the top of the first layer of the isolation layer higher than the top of the first layer of the metal interconnection line is set to be equal to the height of the first layer of the contact hole;
in the step 08, the height of the top of the planarized (N + 1) th isolation layer, which is higher than the top of the (N + 1) th metal interconnection line, is set to be equal to the height of the pad structure.
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