KR20090032491A - Image sensor and method for manufacturing thereof - Google Patents

Abstract

The image sensor according to the embodiment includes a circuit (circuitry) formed by including a lower wiring on the substrate; A photodiode formed on a substrate above the circuit to be electrically connected to the lower interconnection; An anti-reflection film formed on the photodiode; And a color filter formed on the anti-reflection film.

Description

Image sensor and method for manufacturing

Embodiments relate to an image sensor and a manufacturing method thereof.

In general, 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. It is divided into (Image Sensor) (CIS).

In the CMOS image sensor, a photo diode and a MOS transistor are formed in a unit pixel to sequentially detect an electrical signal of each unit pixel in a switching manner to implement an image.

The CMOS image sensor according to the related art may be divided into a photo diode region (not shown) for receiving a light signal and converting the light signal into an electrical signal, and a transistor region (not shown) for processing the electrical signal.

However, the CMOS image sensor according to the related art has a structure in which a photodiode is horizontally disposed with a transistor.

Of course, although the disadvantages of the CCD image sensor are solved by the horizontal CMOS image sensor according to the prior art, there are still problems in the horizontal CMOS image sensor according to the prior art.

That is, according to the horizontal CMOS image sensor of the prior art, a photodiode and a transistor are manufactured to be adjacent to each other horizontally on a substrate. Accordingly, an additional area for the photodiode is required, thereby reducing the fill factor area and limiting the possibility of resolution.

In addition, according to the prior art, cross talk occurs due to the following causes.

First, spectral crosstalk is caused by unwanted light passing through an incomplete color filter.

Second, electrical crosstalk causes long-wavelength carriers to affect adjacent pixels, which causes crosstalk.

Lastly, optical spatial crosstalk is the most important cause of crosstalk. Color filters and microlenses are made of metal and interlayer insulation layers. Because of the (IMD), it is separated from the pixel surface by a certain focal length. At this time, if a few lights are incident through a microlens and a color filter with a constant angle, they may be partially absorbed by adjacent pixels, which may cause crosstalk. Can be induced. If crosstalk occurs continuously, it is a problem for the yield reduction and image characteristics of the image sensor.

In addition, according to the horizontal CMOS image sensor according to the prior art there is a problem that it is very difficult to achieve optimization for the process of manufacturing the photodiode and the transistor at the same time. That is, in a fast transistor process, a shallow junction is required for low sheet resistance, but such shallow junction may not be appropriate for a photodiode.

Further, according to the horizontal CMOS image sensor according to the prior art, the size of the unit pixel is increased to maintain the sensor sensitivity of the image sensor as additional on-chip functions are added to the image sensor. The area for the photodiode must be reduced to maintain the pixel size. However, if the pixel size is increased, the resolution of the image sensor is reduced, and if the area of the photodiode is reduced, the sensor sensitivity of the image sensor is reduced.

Embodiments provide an image sensor and a method of manufacturing the same that can provide a new integration of a circuit and a photodiode.

In addition, the embodiment is to provide an image sensor and a method of manufacturing the same that can be improved with the resolution (Resolution) and sensor sensitivity (sensitivity).

In addition, an embodiment is to provide an image sensor and a method of manufacturing the same that can prevent crosstalk.

In addition, the embodiment is to provide an image sensor and a manufacturing method thereof that can prevent the defect in the photodiode while employing a vertical photodiode.

The image sensor according to the embodiment includes a circuit (circuitry) formed by including a lower wiring on the substrate; A photodiode formed on a substrate above the circuit to be electrically connected to the lower interconnection; An anti-reflection film formed on the photodiode; And a color filter formed on the anti-reflection film.

In addition, the manufacturing method of the image sensor according to the embodiment comprises the steps of forming a circuit (circuitry) including a lower wiring on the substrate; Forming a photodiode on a substrate above the circuit to be electrically connected to the lower interconnection; Forming an anti-reflection film on the photodiode; And forming a color filter on the anti-reflection film.

According to the image sensor and the manufacturing method thereof according to the embodiment, it is possible to provide a vertical integration of the circuit (circuitry) and the photodiode.

In addition, according to the embodiment, the fill factor can be approached to 100% by vertical integration of the transistor circuit and the photodiode.

Further, according to the embodiment, crosstalk can be prevented by employing an antireflection film between the photodiode and the color filter.

Further, according to the embodiment, it is possible to provide higher sensitivity at the same pixel size by vertical integration than in the prior art.

In addition, according to the embodiment it is possible to reduce the process cost for the same resolution (Resolution) than the prior art.

In addition, according to the exemplary embodiment, each unit pixel may implement a more complicated circuit without reducing the sensitivity.

In addition, the additional on-chip circuitry that can be integrated by the embodiment can increase the performance of the image sensor and further reduce the size and manufacturing cost of the device.

Further, according to the embodiment, it is possible to prevent defects in the photodiode while employing a vertical photodiode.

Hereinafter, 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 it is described as being formed "on / under" of each layer, it is understood that the phase is formed directly or indirectly through another layer. It includes everything.

In the description of the embodiment will be described with reference to the structure of the CMOS image sensor (CIS), the present invention is not limited to the CMOS image sensor, it is applicable to all image sensors, such as CCD image sensor.

(Example)

1 is a cross-sectional view of an image sensor according to an embodiment.

The image sensor according to the embodiment includes a circuit (not shown) formed by including a lower wiring 130 on the substrate 110; A photodiode 140 formed on the substrate 110 above the circuit to be electrically connected to the lower wiring 130; An anti-reflection film 150 formed on the photodiode 140; And a color filter 160 formed on the anti-reflection film 150.

According to the image sensor according to the embodiment, it is possible to provide a vertical integration of the circuit (circuitry) and the photodiode, thereby making the fill factor close to 100%.

Further, according to the embodiment, crosstalk can be prevented by employing an antireflection film.

For example, in some embodiments, an anti-reflection film 150 may be formed for each pixel. That is, when the color filter 160 includes the first color filter 161, the second color filter 162, and the third color filter 163, the anti-reflection film 150 may be formed to correspond to each color filter. The first anti-reflection film 151, the second anti-reflection film 152, and the third anti-reflection film 153 may be formed.

As a result, for example, as illustrated in FIG. 1, the direct light L1 and the diffracted light L2 passing through the second color filter 162 may be blocked from being absorbed by adjacent pixels, thereby preventing crosstalk.

In particular, the diffracted light L2 or the tilted light (not shown) passing through the second color filter 162 may be prevented from being absorbed into the adjacent pixel by the second anti-reflection film 152 to prevent crosstalk. .

A method of manufacturing the image sensor according to the embodiment will be described with reference to FIGS. 2 to 3.

First, a circuit (not shown) including the lower wiring 130 is formed on the substrate 110 as shown in FIG. 2.

For example, a transistor (not shown) including a gate insulating layer (not shown) and a gate electrode (not shown) are formed on the substrate 110. The image sensor according to the embodiment may vary in the number of transistors, such as one, two, three, four, five or 1.5 (if shared).

Thereafter, the interlayer insulating layer 120 is formed on the substrate 110 on which the transistor is formed, and the lower wiring 130 is formed. The lower wiring 130 may include a lower metal (not shown) and a plug (not shown). The lower metal may be formed in plural. A barrier metal (not shown) formed of tungsten, titanium, tantalum, or a nitride thereof may be formed on the lower wiring 130.

Next, as shown in FIG. 3, the photodiode 140 is formed on the substrate 110 above the circuit so as to be electrically connected to the lower wiring 130.

For example, the photodiode 140 may be formed by deposition of amorphous silicon. For example, N-type doped amorphous silicon is deposited to form an N-type conductive layer (not shown). Subsequently, n-doped amorphous silicon is deposited on the N-type conductive layer to form an intrinsic layer (not shown). Thereafter, a PIN type photodiode 140 may be formed by depositing P-doped amorphous silicon on the intrinsic layer to form a P-type conductive layer (not shown).

Alternatively, the photodiode 140 may be formed in a crystalline silicon layer (not shown). For example, a separate crystalline silicon layer (not shown) other than the substrate 110 is prepared, and an N-type ion implantation region and a P-type ion implantation region are formed by ion implantation into the crystalline silicon layer to form the photodiode 140. The crystalline silicon layer may be bonded to the substrate 110 so that the photodiode contacts the lower interconnection 130 of the substrate 110. At this time, the region other than the photodiode 140 is removed from the crystalline silicon layer.

Next, a transparent electrode (not shown) may be formed of ITO on the photodiode 140.

Next, an anti-reflection film 150 is formed on the photodiode 140. According to the embodiment, crosstalk can be prevented by employing an antireflection film.

For example, in some embodiments, an anti-reflection film 150 may be formed for each pixel. That is, when the color filter 160 includes the first color filter 161, the second color filter 162, and the third color filter 163, the anti-reflection film 150 may be formed to correspond to each color filter. The first anti-reflection film 151, the second anti-reflection film 152, and the third anti-reflection film 153 may be formed.

For example, the embodiment forms a first color filter 161 after forming the first anti-reflection film 151 on the first photodiode (not shown). Thereafter, after forming the second anti-reflection film 152 on the second photodiode (not shown), the second color filter 162 is formed. Thereafter, after forming the third anti-reflection film 153 on the third photodiode (not shown), the third color filter 163 may be formed.

As a result, for example, as shown in FIG. 3, the direct light L1 and the diffracted light L2 passing through the second color filter 162 may be blocked from being absorbed by the adjacent pixel, thereby preventing crosstalk.

In particular, the diffracted light L2 or the tilted light (not shown) passing through the second color filter 162 may be prevented from being absorbed into the adjacent pixel by the second anti-reflection film 152 to prevent crosstalk. .

In an exemplary embodiment, the anti-reflection film 150 employs a carbon-based material such as a photosensitive film to block the direct light L1 or the diffracted light L2 that has passed through the color filter 160 from being absorbed by adjacent pixels, thereby preventing crosstalk. It can prevent.

In addition, in the embodiment, the thickness of the anti-reflection film 150 may be formed to be about 300 kW to 1,500 kW in consideration of the refractive index of the lower part.

The present invention is not limited to the described embodiments and drawings, and various other embodiments are possible within the scope of the claims.

1 is a cross-sectional view of an image sensor according to an embodiment.

2 to 3 are process cross-sectional views of a manufacturing method of an image sensor according to an embodiment.

Claims (7)

A circuit formed by including a lower wiring on a substrate; A photodiode formed on a substrate above the circuit to be electrically connected to the lower interconnection; An anti-reflection film formed on the photodiode; And And a color filter formed on the anti-reflection film. According to claim 1, The anti-reflection film is an image sensor, characterized in that formed for each pixel (Pixel). According to claim 1, The anti-reflection film Image sensor, characterized in that the carbon-based material. According to claim 1, The thickness of the anti-reflection film is an image sensor, characterized in that about 300 ~ 1,500Å. Forming a circuit on the substrate including a lower wiring; Forming a photodiode on a substrate above the circuit to be electrically connected to the lower interconnection; Forming an anti-reflection film on the photodiode; And Forming a color filter on the anti-reflection film; manufacturing method of an image sensor comprising a. The method of claim 5, Forming the anti-reflection film and forming the color filter, Forming a first color filter after forming a first anti-reflection film on the first photodiode; Forming a second color filter after forming a second anti-reflection film on the second photodiode; And And forming a third color filter after the third anti-reflection film is formed on the third photodiode. The method of claim 5, The anti-reflection film Method of manufacturing an image sensor, characterized in that the carbon-based material.

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