KR20100051197A - Image sensor and method for manufacturing the same - Google Patents

Abstract

An image sensor and a method of manufacturing the same are provided. The image sensor includes a plurality of photodiodes formed at a predetermined distance in the semiconductor substrate, an interlayer insulating film formed on the semiconductor substrate, a plurality of color filter layers formed at regular intervals on the interlayer insulating film, and each color filter layer. And a microlens formed on each of the color filter layers and an anti-reflection film formed on a trapezoidal shape having a longer bottom surface than the upper surface.

Description

Image sensor and manufacturing method thereof {IMAGE SENSOR AND METHOD FOR MANUFACTURING THE SAME}

TECHNICAL FIELD The present invention relates to a semiconductor device, and more particularly, to an image sensor and a method of manufacturing the same.

In general, an image sensor is a semiconductor device that converts an optical image into an electrical signal, and may be broadly classified into a charge coupled device (CCD) image sensor device and a complementary metal oxide semiconductor (CMOS) image sensor device.

The CMOS image sensor includes a photodiode unit for detecting irradiated light and a CMOS logic circuit unit for converting the detected light into an electrical signal and converting the data into electrical signals. As the amount of light received by the photodiode increases, the photosensitivity of the image sensor is increased. ) The characteristics become good.

In order to increase the light sensitivity, a technique in which the fill factor of the photodiode in the total area of the image sensor is increased or the path of the light incident to a region other than the photodiode is changed to focus the photodiode. .

A representative example of the condensing technique is to form a microlens, which is a method of irradiating a larger amount of light to a photodiode by refracting the path of incident light by making a convex microlens with a material having a high light transmittance on the photodiode. to be.

However, there are the following problems in the general CMOS image sensor as described above.

Among the light incident to the photodiode through the microlens, the incident light with the tilt is induced to the photodiode of the adjacent pixel, causing cross talk.

An object of the present invention is to provide a CMOS image sensor and a method of manufacturing the same, which prevents crosstalk by preventing light incident through a microlens from being incident on a neighboring photodiode.

The image sensor according to the embodiment of the present invention for achieving the above object is a plurality of photodiodes formed at a predetermined distance in the semiconductor substrate, an interlayer insulating film formed on the semiconductor substrate, a constant interval on the interlayer insulating film It characterized in that it comprises a plurality of color filter layers formed with a, an anti-reflection film formed in a trapezoidal shape with a lower surface longer than the upper surface between each color filter layer and a micro lens formed on each color filter layer.

Method of manufacturing an image sensor according to an embodiment of the present invention for achieving the above object is a step of forming a plurality of photodiode at a predetermined distance in the semiconductor substrate, and forming an interlayer insulating film on the semiconductor substrate And forming a trapezoidal antireflection film having a bottom surface longer than the top surface between the pixels on the interlayer insulating layer between the pixels in units of pixels, forming each color filter layer between the antireflection films and on each color filter layer. Forming a micro lens.

An image sensor and a method of manufacturing the same according to an embodiment of the present invention by forming a trapezoidal anti-reflection film of the light absorbing material between the color filter layer to prevent crosstalk by preventing light from entering the neighboring photodiode, The sensitivity of the image sensor can be improved.

Hereinafter, the technical objects and features of the present invention will be apparent from the description of the accompanying drawings and the embodiments. Looking at the present invention in detail.

1A illustrates a cross-sectional view of an image sensor in accordance with an embodiment of the present invention.

As shown in FIG. 1A, an image sensor according to an exemplary embodiment of the present invention may include a semiconductor substrate having various transistors (not shown), a photodiode 100 constituting a unit pixel on the semiconductor substrate, and the semiconductor substrate. The interlayer insulating film 200 formed on the entire surface of the insulating film, the green, red, and blue color filter layers 400 formed at regular intervals on the interlayer insulating film 200, and the anti-reflection films formed between each color filter layer 400 ( 320 and 340, the planarization layer 500 formed on the front surface of the semiconductor substrate including the color filter layer 400, and the central portion and the edge portion thereof are hemispherical to correspond to the color filter layer 400 on the planarization layer 500. It includes a micro lens 600 formed with.

Here, the anti-reflection films 320 and 340 are disposed between each color filter layer 400, as shown in FIG. 1B, and have a trapezoidal shape.

Here, the anti-reflection films 320 and 340 may be an opaque metal film having a property of absorbing light, for example, at least one component of Al, Cr, Mo, and Ti, and may have a thickness of 500 to 2000 kPa. .

Since the anti-reflection films 320 and 340 have high absorption of light, the anti-reflection films 320 and 340 absorb the light that is to generate the cross talk, thereby preventing the light from entering the adjacent photodiode.

Here, since the antireflection films 320 and 340 have a length of the bottom side b longer than the length of the upper side a, the side surfaces c of the antireflection films 320 and 340 have a predetermined angle d. .

The predetermined angle d of the anti-reflection films 320 and 340 of the present invention is inclined at a predetermined angle to the side surface of the general anti-reflection films, so that the side surface of the anti-reflection films 320 and 340 is inclined at a predetermined angle. The absorption rate is higher with respect to the incident light.

Hereinafter, a manufacturing method of an image sensor according to an exemplary embodiment of the present invention will be described with reference to FIGS. 2A to 2C.

As shown in FIG. 2A, a photodiode 100 and various transistors (not shown) forming a unit pixel of a CMOS image sensor are formed on a semiconductor substrate.

Subsequently, an interlayer insulating layer 200 is formed on the entire surface of the semiconductor substrate including the photodiode 100. Here, the interlayer insulating film 200 may be formed in multiple layers, and may use an oxide such as USG (Undoped Silicate Glass).

Before forming the color filter array on the interlayer insulating layer 200, a plurality of antireflection films are patterned by photolithography in a lattice pattern on the pixel array 10.

That is, after applying the anti-reflection film material on the interlayer insulating film 200, by selectively patterning the anti-reflection film material through a photo and exposure process to form a plurality of anti-reflection films formed in a grid pattern between the pixel array 10 Form.

Here, the anti-reflection film material may be formed of an opaque metal film having a property of absorbing light, for example, at least one of Al, Cr, Mo, and Ti, and may be formed to a thickness of 500 to 2000 kPa.

In addition, the anti-reflection film has a length of the bottom side (b) longer than the length of the top side (a), as shown in FIG. Have a trapezoidal shape.

The angle d of the anti-reflection film allows to adjust the slope of the trapezoidal side surface by changing the focus during exposure conditions of the lithography.

The predetermined angle d of the anti-reflection films 320 and 340 of the present invention is inclined at a predetermined angle compared to the side surfaces of the general anti-reflection films at a substantially perpendicular angle with respect to the bottom surface. There is an effect that the absorption is high for the light incident to the side.

In addition, since the anti-reflection films 320 and 340 have high absorption of light, the anti-reflection films 320 and 340 may absorb light that has generated cross talk, thereby preventing the light from eventually entering the adjacent photodiode.

Thereafter, as shown in FIG. 2C, the color filter layer 400 is formed on the interlayer insulating film 200 on which the anti-reflection films 320 and 340 are formed. Here, in the method of forming each color filter layer 400, the color resist may be coated, and each color filter layer 400 may be formed by a photolithography process using a separate mask.

Thereafter, as shown in FIG. 2D, a planarization layer 500 is formed on the entire surface of the substrate including each color filter layer 400, and a microlens photoresist (not shown) is thickly coated on the planarization layer 500. Thereafter, exposure and development processes using a predetermined photo mask are performed to remove photoresist between each color filter by a predetermined width, thereby forming a plurality of micro lenses 600 spaced apart from each other.

Thereafter, a reflow process may be performed to form a micro lens in a dome shape, and to form a low temperature oxide film to protect the surface of the micro lens 600.

Looking at the flow of light of the image sensor formed by the above-described manufacturing method with reference to Figure 1a, the light (L1) and the micro lens 600 that is incidentally passed through the gap (gap) of the micro-lenses 600 By absorbing the light (L2) refracted through the but not focused on the photodiode by the reflection inside the color filler array 400 by the anti-reflection film (320 and 340), the sensitivity of the image sensor Can be improved.

1A and 1B are cross-sectional views of an image sensor in accordance with one embodiment of the present invention.

2A to 2D are cross-sectional views for a method of manufacturing an image sensor according to an embodiment of the present invention.

Claims (7)

A plurality of photodiodes formed at a predetermined distance in the semiconductor substrate; An interlayer insulating film formed on the semiconductor substrate; A plurality of color filter layers formed at regular intervals on the interlayer insulating film; An anti-reflection film formed between the respective color filter layers in a trapezoidal shape having a longer surface than an upper surface thereof; And And a micro lens formed on each of the color filter layers. The method of claim 1, The anti-reflection film CMOS image sensor, characterized in that formed of at least one component of Al, Cr, Mo, Ti. The method of claim 1, The anti-reflection film is CMOS image sensor, characterized in that formed to a thickness of 500 ~ 2000Å. Forming a plurality of photodiodes at a predetermined distance in the semiconductor substrate; Forming an interlayer insulating film on the semiconductor substrate; Forming a trapezoidal anti-reflection film having a bottom surface longer than an upper surface of the photodiode on a pixel basis between the pixels on the interlayer insulating film; Forming each color filter layer between the anti-reflection films; And And forming a microlens on each of the color filter layers. The method of claim 4, wherein The anti-reflection film is a method of manufacturing a CMOS image sensor, characterized in that formed of at least one component of Al, Cr, Mo, Ti. The method of claim 4, wherein The anti-reflection film is a manufacturing method of the CMOS image sensor, characterized in that formed in a thickness of 500 ~ 2000Å. The method of claim 4, wherein The slope of the side surface of the anti-reflection film is a manufacturing method of the CMOS image sensor, characterized in that by changing the focus (focus) of the exposure conditions of the lithography (lithograph).

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