KR100835114B1 - Image sensor and method for manufacturing therof - Google Patents

Abstract

An image sensor and a method of manufacturing the same are provided to secure the reliability by prevent cross talk and noise from being occurred. An image sensor includes a semiconductor substrate(10), a metal wire layer(30), an upper insulation layer(50), final metal wires(41,42), a blocking layer(43), a passivation layer(60), a micro lens(70). The semiconductor substrate includes an optical sensing device(20) in which a red optical sensor, a green optical sensor, and a blue optical sensor are vertically arranged. The metal wire layer includes a lower wire and an interlayer dielectric, which are formed on the semiconductor substrate. The upper insulation layer is formed on the metal wire layer. The final metal wires and the blocking layer are formed to penetrate the upper insulation layer. The passivation layer is formed on the upper insulation layer including the final metal wires and the blocking layer. The micro lens is formed on the passivation layer, and forms a gap with an adjacent lens. The blocking layer is formed at a position corresponding to the gap of the micro lens.

Description

Image Sensor and Method for Manufacturing therof

1 to 6 are diagrams illustrating a manufacturing process of an image sensor according to an embodiment.

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

An image sensor is a semiconductor device that converts an optical image into an electrical signal, and is largely a charge coupled device (CCD) and a CMOS (Complementary Metal Oxide Silicon) image sensor. Sensor) (CIS).

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

In particular, apart from the conventional method of arranging one color of red-green-blue in one pixel (pixel), all three colors are arranged vertically in one pixel to have a horizontal structure. A vertical image sensor has been developed that can achieve about three times higher image quality than an image sensor.

Since a variety of colors can be expressed without a separate color filter process of the vertical image sensor, there is an advantage of increasing productivity and reducing production cost.

The vertical image sensor includes a unit pixel including a photodiode on a semiconductor substrate and a logic circuit area for processing and converting a signal from the unit pixel into data.

Efforts have been made to increase the fill factor of the light sensing region in the entire image sensor device in order to increase the light sensitivity. However, since the logic circuit region cannot be removed, this effort is limited in a limited area.

Therefore, a condensing technology has emerged to change the path of light incident to an area other than the light sensing area to raise the light sensitivity, and collect the light into the light sensing area. For this purpose, the image sensor uses a method of forming a microlens on the color filter. I use it.

However, even if the microlens is formed, not all of the refracted light is collected in the light sensing region.

In particular, when the light refracted by the microlenses enters the CMOS circuit area, which is a region other than the light sensing region, the light constitutes a noise component and causes a deterioration in image quality, thus acting as an adverse effect on the characteristics of the image sensor.

To this end, after forming a metal wiring layer and a protective layer on which the metal wiring connected to the unit pixel is formed, a light blocking film is partially formed on the protective layer, but the manufacturing process is increased and the product is increased due to the complicated and additional process. This will lead to a decrease in yield.

Embodiments relate to an image sensor and a method of manufacturing the same, in which a blocking film is formed to block light incident to a CMOS circuit of a unit pixel when the final metallization is formed.

In addition, the blocking film is formed at the same time when the final metal wiring is formed to provide an image sensor and a manufacturing method that can increase the product yield due to the reduction of the number of processes.

An image sensor of an embodiment includes a semiconductor substrate including a photosensitive device; A metal wiring layer including a lower wiring and an interlayer insulating layer formed on the semiconductor substrate; An upper insulating layer formed on the metal wiring layer; A final metallization and blocking film formed through the upper insulating layer; A protective layer formed on the upper insulating layer including the pad and the blocking layer; Microlenses formed on the protective layer are included.

In addition, the manufacturing method of the image sensor of the embodiment comprises the steps of: forming a metal wiring layer including a lower wiring and an interlayer insulating film on a semiconductor substrate including a photosensitive device; Forming an upper insulating layer on the metal wiring layer; Forming a final metal wiring and a blocking film on the upper insulating layer; Forming a protective layer on the upper insulating layer including the final metallization and a blocking film; And forming a microlens on the protective layer.

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

In the description of this embodiment, when described as being formed "on / over" of each layer, the on / over is directly or through another layer. (indirectly) includes everything formed.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

6 shows the image sensor of this embodiment.

The image sensor of the embodiment includes a semiconductor substrate 10 on which a light sensing element 20 and a CMOS circuit (not shown) are formed; A metal wiring layer 30 including a metal wiring 31 and an interlayer insulating layer 32 formed on the semiconductor substrate 10; An upper insulating layer 50 formed on the metal wiring layer 30; Final metal wirings 41 and 42 and a blocking layer 43 formed through the upper insulating layer 50; A protective layer 60 formed on the upper insulating layer 50 including the final metal wirings 41 and 42 and the blocking layer 43; The microlens 70 formed on the protective layer 60 is included.

The blocking layer 43 is formed in the gap region between the microlenses 70 to block light that does not pass through the microlens 70, thereby preventing light from entering the CMOS circuit region to prevent crosstalk and noise. The occurrence is blocked.

Since the final metal wirings 41 and 42 and the blocking layer 43 are formed of the same material and are formed at the same time, the product yield may be increased due to the decrease in the number of processes.

Hereinafter, a manufacturing process of the image sensor according to the present embodiment will be described with reference to FIGS. 1 to 6.

Referring to FIG. 1, a pixel region including a photosensitive device 20 and a peripheral circuit region (not shown) are formed in a semiconductor substrate 10.

The pixel region includes a photosensitive device 20 and a CMOS transistor structure (not shown) for processing light generated by the photosensitive device 20.

The photosensitive device 20 is formed by including a red photodiode, a green photodiode, and a blue photodiode, and thus, three colors in one pixel. All of them are arranged vertically to achieve high quality images.

In addition, the photosensitive device 20 may express various colors without a separate color filter process.

A plurality of metal wiring layers 30 including metal wirings M1 and M2 31 and an interlayer insulating layer 32 are formed on the semiconductor substrate 10 including the pixel region.

The metal wires M1 and M2 31 are intentionally disposed to be connected to the power line, the signal line, and the pixel area so as not to block the light incident to the photosensitive device 20.

The metal layer 40 is formed on the metal wiring layer 30 to form the final metal wirings M3 and 41 and 42. For example, the metal layer 40 may be formed of a material such as TiN, Ti, Al, W, or the like.

Referring to FIG. 2, first (100, 200) and second masks (300) are formed on the metal layer (40).

The first and second masks 100, 200, and 300 are formed by applying a photoresist film onto the metal layer 40 and by an exposure and development process.

The first masks 100 and 200 are selectively patterned on the metal layer 40 in the region where the final metal wiring is to be formed.

The first masks 100 and 200 may be masks for forming pads.

The second mask 300 is selectively patterned on the metal layer 40 in a region in which a microlens is to be formed.

Referring to FIG. 3, the metal layer 40 is etched using the first, second, and third masks 100, 200, and 300 as etching masks to form final metal wirings 41, 42, and a blocking layer 43.

The final metallizations 41 and 42 may be pads.

Since the blocking layer 43 is formed in the gap region between the microlenses formed thereafter, the blocking layer 43 may block light that does not pass through the microlens 70.

Since the blocking layer 43 is formed together when the final metal wirings 41 and 42 are formed, an additional process for forming the conventional blocking layer is not required.

Referring to FIG. 4, after removing the first and second masks, an insulating film is deposited on the semiconductor substrate 10 including the final metal wirings 41 and 42 and the blocking layer 43 to form an upper insulating layer ( 50) is formed. For example, the upper insulating layer 50 may be formed of an oxide film.

Referring to FIG. 5, a protective layer 60 is formed on the upper insulating layer 50. The protective layer 60 may be formed of a single layer of an oxide film or a nitride film, and may be formed of a stacked structure of the films.

Referring to FIG. 6, a microlens 70 for condensing the light sensing element 20 onto the protective layer 60 is formed.

The microlens 70 applies a photoresist for forming a microlens onto the protective layer 60 through a spin process. After selectively exposing and developing the photoresist film, a microlens pattern is formed to correspond to each unit pixel. Thereafter, a reflow process is performed to form a dome-shaped microlens 70 having a convex shape.

In this case, the microlens 50 may have a gap formed between the microlenses 70 to prevent a bridge or merge with a neighboring microlens.

In the present exemplary embodiment, since the blocking layer 43 is formed in the upper insulating layer 50 at the position corresponding to the gap region of the microlens 70, if the incident light is out of the microlens 70, When going straight to the gap region of the lens 70 reaches the blocking film 43, the light is prevented from entering the region other than the light sensing element (20).

Therefore, light that does not pass through the microlens 70 may not be incident to the photosensitive device 20, thereby improving light sensitivity of the image sensor.

In addition, since the non-condensed light may be blocked by the blocking film 43 between the gaps D2 of the microlens 70, the noise and crosstalk of the photodiode disposed on the semiconductor substrate 10 may be prevented. This can improve the quality of the image sensor by blocking its occurrence.

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

In the image sensor and the manufacturing method of the embodiment, it is possible to secure the reliability of the image sensor by preventing crosstalk and noise generation by the light blocking film under the gap region of the microlens.

In addition, since only light passing through the microlenses is incident on a unit pixel, optical efficiency and resolution may be increased.

In addition, since the light blocking film is formed at the same time as the final metal wiring is formed, it is possible to increase the product yield according to the process number reduction.

Claims (7)

A semiconductor substrate including a photosensitive device in which a red photosensitive device, a green photosensitive device, and a blue photosensitive device are vertically arranged; A metal wiring layer including a lower wiring and an interlayer insulating layer formed on the semiconductor substrate; An upper insulating layer formed on the metal wiring layer; A final metallization and blocking film formed through the upper insulating layer; A protective layer formed on the upper insulating layer including the final metallization and a blocking film; And A microlens formed on the protective layer and having a gap with a neighboring lens; The blocking film is formed at a position corresponding to the gap of the micro lens. delete delete Forming a photosensitive device including a red photosensitive device, a green photosensitive device, and a blue photosensitive device on a semiconductor substrate; Forming a metal wiring layer including a lower wiring and an interlayer insulating layer on the semiconductor substrate including the photosensitive device; Forming an upper insulating layer including a final metal wiring and a blocking layer on the metal wiring layer; Forming a protective layer on the upper insulating layer; And Forming a microlens having a gap with a neighboring lens on the protective layer, The blocking film is a manufacturing method of the image sensor is formed at a position corresponding to the gap of the micro lens. The method of claim 4, wherein The final metal wiring and the blocking film is a method of manufacturing an image sensor comprising the same time formed. The method of claim 4, wherein Forming the final metal wiring and the blocking film, Depositing a metal material on the metallization layer; Forming a first mask pattern on the metal material corresponding to the metal wiring, and forming a second mask pattern having a width corresponding to a gap of the microlens; And etching the metal material to form the final metal wiring and the blocking layer by an etching process using the first and second mask patterns as masks. delete

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