KR100997334B1 - Image Sensor and Method for Manufacturing Thereof - Google Patents

Abstract

An image sensor according to an embodiment includes a semiconductor substrate including a photodiode and a CMOS circuit; A lower insulating layer disposed on the semiconductor substrate; A light emitting layer disposed on the lower insulating layer; A contact plug passing through the light emitting layer and the lower insulating layer and connected to the CMOS circuit; An upper insulating layer including a metal wiring disposed on the phosphor layer to be connected to the contact plug; A color filter disposed on the upper insulating layer; And a micro lens disposed on the color filter.

Image sensor, photodiode, fluorescent material

Description

Image Sensor and Method for Manufacturing Thereof}

In an embodiment, an image sensor and a method of manufacturing the same are disclosed.

The image sensor is a semiconductor device that converts an optical image into an electrical signal, and includes a charge coupled device (CCD) image sensor and a complementary metal oxide silicon (CMOS) image sensor (CIS). do.

The CMOS image sensor implements an image by sequentially detecting an electrical signal of each unit pixel by a switching method by forming a photodiode and a MOS transistor in the unit pixel.

As the design rule of the CMOS image sensor is gradually reduced, the size of the unit pixel may be reduced, thereby reducing the light sensitivity. In order to increase the light sensitivity, a micro lens is formed on the color filter.

However, since the light receiving area is narrowed with the integration of devices, it is required to improve the fill factor of the photodiode.

The embodiment provides an image sensor and a method of manufacturing the same, which can improve the amount of received light by forming a phosphor inside the interlayer insulating film.

An image sensor according to an embodiment includes a semiconductor substrate including a photodiode and a CMOS circuit; A lower insulating layer disposed on the semiconductor substrate; A light emitting layer disposed on the lower insulating layer; A contact plug passing through the light emitting layer and the lower insulating layer and connected to the CMOS circuit; An upper insulating layer including a metal wiring disposed on the phosphor layer to be connected to the contact plug; A color filter disposed on the upper insulating layer; And a micro lens disposed on the color filter.

A method of manufacturing an image sensor according to an embodiment includes forming a photodiode and a CMOS circuit on a semiconductor substrate; Forming a lower insulating layer on the semiconductor substrate; Forming a light emitting layer on the lower insulating layer; Forming a contact plug penetrating the light emitting layer and the lower insulating layer and connected to the CMOS circuit; Forming an upper insulating layer on the phosphor layer, the upper insulating layer being connected to the contact plug; Forming a color filter on the upper insulating layer; And forming a micro lens on the color filter.

According to the image sensor and the method of manufacturing the same according to the embodiment, the light emitting layer may be formed on the photodiode, thereby increasing the light reception amount of the photodiode.

An image sensor and a method of manufacturing the same according to an embodiment will be described in detail with reference to the accompanying drawings.

In the description of the embodiments, where described as being formed "on / over" of each layer, the on / over may be directly or through another layer ( indirectly) includes everything formed.

5 is a cross-sectional view illustrating an image sensor according to an embodiment.

The image sensor according to the embodiment includes a semiconductor substrate 10 including a photodiode 40 and a transistor 30, a lower insulating layer 50 disposed on the semiconductor substrate 10, and the lower insulating layer. The light emitting layer 70 disposed on the 50, the contact plugs 90 and 100 connected to the transistor 30 through the light emitting layer 70 and the lower insulating layer 50, and the contact plugs 90 and 100. Upper insulating layers 110, 120, and 130 including metal wirings M1, M2, and M3 disposed on the light emitting layer 70 to be connected to the light emitting layer 70; The micro lens 150 is disposed on the color filter 140.

The emission layer 70 may be formed of at least one of an organic phosphor layer, an inorganic phosphor layer, and an organic-inorganic phosphor layer. The light emitting layer 70 may be disposed for each unit pixel to emit light with the unit pixel. That is, the light emitting layer 70 may be a fluorescent material exhibiting the same color as the color filter 140. For example, the emission layer 70 may represent red, green, and blue. Therefore, the light emitting layer 70 can generate light corresponding to each photodiode.

Among the organic phosphors, the material representing red may be a derivative of poly-phenylenevinylene (PPV) or poly-alkylthiophene (PAT). Among the organic phosphors, the material representing green may be a derivative of poly-phenylenevinylene (PPV) or poly-alkylthiophene (PAT). Among the organic phosphors, blue may be a derivative of poly-vinylcarbazole (PVK).

The material representing red in the inorganic phosphor may be Eu: Y ₂ O ₃ and Eu: CaS. Material that exhibits a green of the inorganic phosphor is _{Tb: Y 2 SiO 5, Mn} : Zn 2 SiO 4:, Eu 2 +: SrGa 2 S 4 may be. Material that exhibits a blue of the inorganic phosphor is Eu ⁺ _2: can be _{SrMgSi 2 O 7: BaMgAl 10 O} 17, Eu 2 +.

The material representing red in the organic-inorganic phosphor may be Eu (DBM) ₃ (phen). Among the organic-inorganic phosphors, blue may be Alq (tris- (8-hydroxyquionline) aluminum) or BeBq2 (bis (benzo-quinoline) berellium). The substance representing green in the organic-inorganic phosphor may be DPVBI (4-4'-bis (2,2-diphenylethen-1-yl) -diphenyl).

Since the light emitting layer 70 is formed of the polymer or the low molecular fluorescent material as described above, the light emitting layer 70 may also generate respective light by the light incident on the photodiode 40. Therefore, the light reception amount of the photodiode 40 can be increased.

First and second transparent electrodes 60 and 80 may be disposed on the upper and lower portions of the emission layer 70. For example, the first and second transparent electrodes 60 and 80 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), and antimony-zinc oxide (AZO).

First and second transparent electrodes 60 and 80 may be formed on upper and lower portions of the emission layer 70 to apply electrical energy to the emission layer 70. Then, light is generated in the light emitting layer 70 and light may be incident on the photodiode 40.

According to the image sensor according to the embodiment, the light emitting layer is formed on the photodiode to increase the light receiving amount of the photodiode.

In addition, transparent electrodes may be formed on the upper and lower portions of the emission layer to generate light in the emission layer. Therefore, the light reception amount of the photodiode can be increased.

1 to 5 are cross-sectional views illustrating a manufacturing process of an image sensor according to an embodiment.

Referring to FIG. 1, a unit pixel including a photodiode 40 is formed on a semiconductor substrate 10.

In the semiconductor substrate 10, an isolation layer 20 defining an active region and a field region is formed. The unit pixel formed in the active region includes a photodiode 40 that receives light and generates photocharges, and a transistor 30 that is connected to the photodiode 40 and converts the received photocharges into an electrical signal. . The transistor 30 may be a gate of a transfer transistor in a transistor structure including a transfer transistor, a reset transistor, a drive transistor, a select transistor, and the like.

After the related devices including the photodiode 40 are formed, a lower insulating layer 50 is formed on the semiconductor substrate 10. The lower insulating layer 50 may be a pre-metal dielectric. For example, the lower insulating layer 50 may be formed of an oxide film material such as TEOS and BPSG.

Referring to FIG. 2, light emitting layers 70 are formed for each unit pixel on the lower insulating layer 50. The light emitting layer 70 is to increase the amount of light received by the photodiode 40 by forming a light emitting material on the photodiode 40. That is, the emission layer 70 may be formed of a fluorescent material and may be a material capable of self-emission. The emission layer 70 may be formed to have colors of red, green, and blue. Therefore, the emission layers 70 having different colors may be formed in the corresponding unit pixels.

When such a fluorescent material absorbs light above a certain energy, the fluorescent material may emit light as much as a band gap. In addition, the phosphorescence time may be controlled by a phosphorescence phenomenon in which a material that emits light by being stimulated with light according to the type of fluorescent material continues to emit light even after the stimulus stops.

Therefore, when the light emitting layer 70 formed of a fluorescent material is formed on the lower insulating layer 50 on the photodiode 40, light is also emitted from the light emitting layer 70 by incident light, and thus the photodiode 40 is formed. Can increase the amount of received light. For example, the emission layer 70 may be formed of any one of an organic phosphor layer, an inorganic phosphor layer, and an organic-inorganic phosphor layer.

The organic phosphor may be formed of a polymer material and formed by a spin on glass (SOG) method. The material representing red of the organic phosphor may be a derivative of poly-phenylenevinylene (PPV) and poly-alkylthiophene (PAT). The material representing the green of the organic phosphor may be a derivative of poly-phenylenevinylene (PPV) and poly-alkylthiophene (PAT). The material expressing blue of the organic phosphor may be a derivative of poly-vinylcarbazole (PVK).

The inorganic phosphor may be formed of a phosphor material by SOG method or spray pyrolysis. The material representing red of the inorganic phosphor may be Eu: Y ₂ O ₃ or Eu: CaS. Materials representing the green of the inorganic phosphor is _{Tb: Y 2 SiO 5, Mn} : Zn 2 SiO 4, Eu 2 +: SrGa 2 S 4 may be. Material exhibiting blue of the inorganic phosphor is Eu ⁺ _2: may be a _{Sr 3 MgSi 2 O 7: BaMgAl} 10 O 17, Eu 2 +.

The organic-inorganic phosphor may be formed by using a low molecular weight material and vacuum deposition by evaporation. The material representing red of the organic-inorganic phosphor may be Eu (DBM) 3 (phen)). The material representing the green of the organic-inorganic phosphor may be Alq (tris- (8-hydroxyquinoline) aluminium) and BeBq ₂ (bis (benzo- quinoline) berellium). The material representing the blue of the organic-inorganic phosphor may be DPVBi (4,4'-bis (2,2-diphenylethen-1-yl) -diphenyl).

As described above, the light emitting layer 70 may be formed for each unit pixel, and light may be incident on the photodiode of the unit pixel.

In order to form the emission layer 70, a phosphor layer (not shown) is formed on the lower insulating layer 50, and a mask pattern (not shown) is formed at a position corresponding to the unit pixel on the phosphor layer. When the phosphor layer is etched using the mask pattern as an etching mask, the emission layer 70 is formed at a position corresponding to the unit pixel. Therefore, since the light emitting layers 70 having respective colors are formed on the lower insulating layer 50 corresponding to the photodiode 40, the amount of light received by the photodiode 40 may be increased.

Referring to FIG. 3, first and second transparent electrodes 60 and 80 may be formed on and under the emission layer 70. That is, after the first transparent electrode 60 is formed on the lower insulating layer 50, the light emitting layer 70 and the second transparent electrode 80 may be sequentially formed. Then, the light emitting layer 70 is interposed between the first and second transparent electrodes 60 and 80.

The first and second transparent electrodes 60 and 80 may forcibly emit the light emitting layer 70 by applying electrical energy to the light emitting layer 70. For example, the first and second transparent electrodes 60 and 80 may be formed of any one of indium tin oxide (ITO), indium zinc oxide (IZO), and antimony-zinc oxide (AZO).

Accordingly, when electrical energy is applied to the light emitting layer 70 by the first and second transparent electrodes 60 and 80, light is generated in the light emitting layer 70, thereby improving the light sensitivity of the photodiode 40. . Particularly, when electrical energy is applied to the light emitting layer 70 by the first and second transparent electrodes 60 and 80 when the light amount is low in the image sensor, light is generated in the light emitting layer 70 so that the photodiode 40 The light can proceed. Accordingly, the light receiving amount of the photodiode 40 may be compensated for when light having low efficiency or when the amount of light is small. Meanwhile, the first and second transparent electrodes 60 and 80 may not be formed.

In the description of the embodiment, for example, the first and second transparent electrodes 60 and 80 are formed on the upper and lower portions of the emission layer 70.

Referring to FIG. 4, contact plugs 90 and 100 penetrating the lower insulating layer 50, the light emitting layer 70, the first transparent electrode 60, and the second transparent electrode 80 are formed. The contact plugs 90 and 100 are formed through the lower insulating layer 50, the light emitting layer 70, the first transparent electrode 60, and the second transparent electrode 80 to form a gate and floating diffusion of the transistor 30. It may be electrically connected to the area. The contact plugs 90 and 100 form a photoresist pattern (not shown) on the second transparent electrode 80 and then gate and float the gates of the transistor 30 by an etching process using the photoresist pattern as an etching mask. A contact hole for selectively exposing the diffusion region is formed. The contact plugs 90 and 100 may be formed by filling metal materials such as tungsten and titanium in the contact holes.

Referring to FIG. 5, a first insulating layer 110 including a first metal wire M1 is formed on the second transparent electrode 80 including the contact plugs 90 and 100.

The first insulating layer 110 is an inter-metal dielectric layer (IMD), and may be formed of an oxide film or a nitride film.

The first metal wire M1 may be formed of various conductive materials including metals, alloys, or silicides. For example, the first metal wire M1 may be formed of aluminum, copper, cobalt or tungsten.

The first metal wire M1 may be formed to deposit a metal layer on the second transparent electrode 80 and to be connected to the contact plugs 90 and 100 by photolithography and etching. That is, the first metal wire M1 may be in a state of being connected to the transistor by a contact plug. In addition, the first metal wire M1 may be intentionally laid out so as not to block light incident to the photodiode 40.

Third including the second insulating layer 120 and the third metal wiring (M3) including the second metal wiring (M2) on the first insulating layer 110 including the first metal wiring (M1). The insulating layer 130 is sequentially formed. The first, second and third metal wires M1, M2, and M3 may be electrically connected by via plugs.

Referring to FIG. 6, a color filter 140 and a micro lens 150 are formed on the third insulating layer 130.

Although not shown, a passivation layer may be formed before forming the color filter 140. In addition, although not shown, when the step is formed in the color filter 140, a planarization layer may be formed on the color filter 140 to compensate for the step.

The color filter 140 uses dyed photoresist, and one color filter 140 is formed for each unit pixel to separate colors from incident light. Each of the color filters 140 represents a different color and may be formed of three colors of red, green, and blue.

That is, the color filter 140 may be formed to have the same color as the light emitting layer 70.

The microlens 150 may be formed by forming a photoresist pattern for forming a microlens and then performing a reflow process. The microlens 150 may be formed one by one for each unit pixel to condense light to the photodiode.

According to the manufacturing method of the image sensor according to the embodiment, the light emitting layer is formed on the photodiode to increase the light reception amount of the photodiode.

In addition, the light emitting layer is formed of a fluorescent material that emits self, so that the amount of light received by the photodiode may be increased.

In addition, the amount of light received by the photodiode is increased to improve image characteristics of the image sensor.

In addition, the light emitting layers may be formed in different colors to emit light with a corresponding photodiode.

In addition, the light emitting layer may have the same color as the color filter forming the unit pixel, thereby improving light sensitivity of the photodiode.

In addition, transparent electrodes may be formed on upper and lower portions of the light emitting layer to self-emit the light emitting layer. Therefore, when the efficiency of light incident on the photodiode decreases or the amount of light decreases, the light-receiving amount of the photodiode can be increased by generating light by operating the light emitting layer.

The above-described embodiments are not limited to the above-described embodiments and drawings, and it is common in the technical field to which the present embodiments belong that various changes, modifications, and changes can be made without departing from the technical spirit of the present embodiments. It will be apparent to those who have

1 to 6 are cross-sectional views illustrating a manufacturing process of an image sensor according to an embodiment.

Claims (8)

A semiconductor substrate including a photodiode and a transistor; A lower insulating layer disposed on the semiconductor substrate; A light emitting layer disposed on the lower insulating layer; A contact plug connected to the transistor through the light emitting layer and the lower insulating layer; An upper insulating layer including a metal wiring disposed on the light emitting layer to be connected to the contact plug; A color filter disposed on the upper insulating layer; And A micro lens disposed on the color filter, An image sensor having a transparent electrode formed above and below the light emitting layer. The method of claim 1, The emission layer is an image sensor formed of at least one of an organic phosphor layer, an inorganic phosphor layer and an organic-inorganic phosphor layer. delete The method of claim 1, The light emitting layer has an image sensor of any one of red, green and blue. Forming a photodiode and a transistor in the semiconductor substrate; Forming a lower insulating layer on the semiconductor substrate; Forming a light emitting layer on the lower insulating layer; Forming a contact plug penetrating the light emitting layer and the lower insulating layer to be connected to the transistor; Forming an upper insulating layer on the light emitting layer so as to be connected to the contact plug; Forming a color filter on the upper insulating layer; And Forming a micro lens on the color filter; And forming transparent electrodes on the upper and lower portions of the light emitting layer. The method of claim 5, The emission layer is a method of manufacturing an image sensor formed of at least one of an organic phosphor layer, an inorganic phosphor layer and an organic-inorganic phosphor layer. The method of claim 5, Forming the light emitting layer, Forming a phosphor layer having any one of red, green, and blue colors on the lower insulating layer; Forming a mask pattern on the phosphor layer; And And etching to correspond to a unit pixel by using the mask pattern as an etching mask. delete

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