KR20060077149A - Color filter array of image sensor and forming method thereof - Google Patents

Abstract

The present invention is to provide a method for forming a metal line using copper of the image sensor that can prevent the deterioration of optical characteristics due to metal contamination by removing the copper contamination generated in the chemical mechanical polishing process when using copper as a metal line, To this end, the present invention, the first overcoating layer provided on the substrate; A first color filter provided on the first overcoating layer; A second color filter provided on the first overcoating layer to be spaced apart from the first color filter; A second overcoating layer provided on the first color filter and the second color filter; And a third color filter provided on the second overcoating layer so as not to overlap with the first color filter and the second color filter.

In addition, the present invention, forming a first overcoating layer on the substrate; Forming a first color filter on the first overcoating layer; Forming a second color filter on the first overcoating layer to be spaced apart from the first color filter; Forming a second overcoating layer on the first color filter and the second color filter; And forming a third color filter on the second overcoating layer so as not to overlap with the first color filter and the second color filter.

CMOS image sensor, overcoating layer (OCL), black wire, residue, color filter.

Description

Color filter array of image sensor and its formation method {COLOR FILTER ARRAY OF IMAGE SENSOR AND FORMING METHOD THEREOF}             

1 is a photograph showing a state in which black line defects occur.

Figure 2 is a planar photograph showing a black line bad state after the green color filter formed.

3 is a SEM photograph showing black lines of horizontal linearity.

4 is a plan view showing a CMOS image sensor of the present invention having a pixel structure arranged in 5 * 5.

FIG. 5 is a cross-sectional view of a color filter array of a CMOS image sensor according to an exemplary embodiment of the present disclosure taken from FIG. 4 in a-a 'and b-b' directions. FIG.

FIG. 6 is a cross-sectional view of a color filter array of a CMOS image sensor according to another exemplary embodiment of the present invention taken along the direction of a-a 'and b-b' of FIG. 4; FIG.

7A to 7C are cross-sectional views illustrating a color filter array forming process of a CMOS image sensor according to an exemplary embodiment of FIG. 5.

8A through 8C are cross-sectional views illustrating a color filter array forming process of a CMOS image sensor according to another exemplary embodiment of FIG. 6.

9 is a SEM photograph corresponding to an embodiment of FIG. 5.                 

Explanation of symbols on the main parts of the drawings

OCL1, OCL2, OCL3: Overcoat Layer RGB: Color Filter

The present invention relates to a method for manufacturing an image sensor, and more particularly, to a color filter array of an image sensor having a laminated structure for preventing black line defects and a method for manufacturing the same.

The image sensor is a semiconductor device that converts an optical image into an electrical signal. Among them, a charge coupled device (CCD) is a device in which charge carriers are stored and transported in a capacitor while individual MOS capacitors are located in close proximity to each other.

On the other hand, CMOS (Complementary MOS) image sensors use CMOS technology that uses a control circuit and a signal processing circuit as peripheral circuits to make MOS transistors as many as the number of pixels, and to use them. It is an element employing a switching method that detects the output of a pixel in turn.

In the current CMOS image sensor color filter formation, a defect called black line due to the problem of the color filter material itself is continuously present.

1 is a photograph showing a state in which black line defects occur.                         

Referring to FIG. 1, it can be seen that an abnormal occurrence in the form of a line occurs after mounting in the supply chip as shown in 'X'. This black line defect is analyzed to occur in 10% of the supply chip.

FIG. 2 is a planar photograph illustrating a black line defect state after the green (G) color filter is formed, and it may be confirmed that black lines are generated at the portion 'Y'.

3 is a SEM photograph showing black lines of horizontal linearity.

Referring to (a) and (b) of FIG. 3, it is possible to see a donor on both blue (B) and red (R), which can be seen to be contrasted with other normal pixels.

As described above, the defect rate is about 10% of the total chip, and is mainly present at the wafer edge. Black line defects are not found in one single color filter, and are mainly found when two or more colors are stacked.

In the color filter, an unexposed portion after exposure is melted in a developer to form a desired shape. The debris of the color filter, which melts during the development process, is not removed by zebra, and reacts with the lower color layer to cause abnormal color defects, thereby generating black lines.

The present invention has been proposed to solve the above problems of the prior art, and an object thereof is to provide a color filter array of an image sensor capable of suppressing black line defects, and a manufacturing method thereof.

The present invention to achieve the above object, the first overcoating layer provided on the substrate; A first color filter provided on the first overcoating layer; A second color filter provided on the first overcoating layer to be spaced apart from the first color filter; A second overcoating layer provided on the first color filter and the second color filter; And a third color filter provided on the second overcoating layer so as not to overlap with the first color filter and the second color filter.

In addition, the present invention to achieve the above object, the first overcoating layer provided on the substrate; A first color filter provided on the first overcoating layer; A second overcoating layer provided on the first color filter; A second color filter provided on the second overcoating layer so as not to overlap with the first color filter; A third overcoating layer provided on the second color filter; And a fourth color filter provided on the third overcoating layer so as not to overlap with the first color filter and the second color filter.

In addition, to achieve the above object, the present invention comprises the steps of forming a first overcoat layer on a substrate; Forming a first color filter on the first overcoating layer; Forming a second color filter on the first overcoating layer to be spaced apart from the first color filter; Forming a second overcoating layer on the first color filter and the second color filter; And forming a third color filter on the second overcoating layer so as not to overlap with the first color filter and the second color filter.

In addition, to achieve the above object, the present invention comprises the steps of forming a first overcoat layer on a substrate; Forming a first color filter on the first overcoating layer; Forming a second overcoating layer on the first color filter; Forming a second color filter on the second overcoating layer so as not to overlap with the first color filter; Forming a third overcoating layer on the second color filter; And forming a fourth color filter on the third overcoating layer so as not to overlap with the first color filter and the second color filter.

In the conventional case, when the color filters are stacked with different colors, the color filters and the color filters are in direct contact with each other. Therefore, the present invention can reduce black line defects by arranging the color filters in a stacked structure such that there is no direct contact between neighboring color filters and by arranging a plurality of overcoating layers therebetween.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. do.

4 is a plan view showing a CMOS image sensor of the present invention having a pixel structure arranged in 5 * 5.

Referring to FIG. 4, three colors of RGB are arranged in a lattice pattern, and as is well known, the G (green) color has twice the pixel distribution of each of the other R (red) and B (blue). . A first overcoating layer OCL1 is disposed below the color filter array of RGB.

Each color filter RGB is alternately arranged in a stacked structure, and each color filter is separated by a plurality of overcoating layers.

Meanwhile, although the color distribution of RGB is taken as an example in the embodiment of the present invention, it is also applicable to the case of Y (yellow) Mg (magenta) Cy (cyan) color distribution, which is a complementary color of RGB.

FIG. 5 is a cross-sectional view illustrating a color filter array of a CMOS image sensor according to an exemplary embodiment of the present invention taken along the direction of a-a 'and b-b' of FIG. 4.

Referring to FIG. 5, a first overcoating layer OCL1 is disposed on a substrate (not shown) on which a photodiode (not shown) and a plurality of metal lines (not shown) are formed. The first overcoating layer OCL1 is used to prevent defects and to secure process margins when forming the color filter array due to a step generated due to the formation of a lower metal line.

On the first overcoating layer OCL1, color filters of R and B colors are spaced apart from each other, and a second overcoating layer OCL2 is disposed between and on top of the color filters of R and B colors. A color filter of G color is disposed on the second overcoating layer OCL2 so as not to overlap with color filters of R and B colors, and a third overcoating layer OCL3 is disposed on the color filter of G color.

The third overcoating layer OCL3 is used to reduce the step difference caused by the G color filter and is used to secure the process margin when forming the subsequent microlens.

Here, since the arrangement of RGB is exemplary, the arrangement in which they are stacked may be changed.

6 is a cross-sectional view illustrating a color filter array of a CMOS image sensor according to another exemplary embodiment of the present disclosure, taken along the a-a 'and b-b' directions of FIG. 4.

Referring to FIG. 6, a first overcoating layer OCL1 is disposed on a substrate (not shown) on which a photodiode (not shown) and a plurality of metal lines (not shown) are formed.

Color filters of B color are arranged at regular intervals, and a second overcoating layer OCL2 is disposed between and above the color filters of B color.

On the second overcoating layer OCL2, a color filter of R color is disposed so that the color filters of B color do not overlap each other.

A third overcoating layer OCL3 is disposed between and above the color filter of R color. A color filter of G color is disposed on the third overcoating layer OCL3 so as not to overlap with color filters of R and B colors, and a fourth overcoating layer OCL4 is disposed on the color filter of G color.

The fourth overcoating layer OCL4 is used to reduce the step difference caused by the G color filter and is used to secure the process margin when forming the subsequent microlens.                     

Here, since the arrangement of RGB is exemplary, the arrangement in which they are stacked may be changed.

That is, in one embodiment of FIG. 5, color filters of two colors R and B are spaced apart from each other, and in another embodiment of FIG. 6, B, R, and G are arranged on different layers.

As shown in the above embodiment, the present invention can almost completely reduce black line defects caused by direct contact between color filters by isolating each other color filters of different colors using an overcoating layer.

FIG. 9 is an SEM photograph corresponding to one embodiment of FIG. 5.

9, it can be seen that the color filters of the R and G colors are completely isolated by OCL2.

Hereinafter, the color filter array forming process of the CMOS image sensor of the present invention having the above configuration will be described.

7A to 7C are cross-sectional views illustrating a color filter array forming process of the CMOS image sensor according to the exemplary embodiment of FIG. 5.

7A to 7C correspond to a cross section taken along the direction of c-c 'of FIG. 4.

As shown in FIG. 7A, a photodiode (not shown), a transistor, and a plurality of metal lines (not shown) are formed on the substrate SUB.

The first overcoat layer OCL1 is formed on the metal line. The first overcoating layer OCL1 is used to prevent defects and to secure process margins when forming the color filter array due to a step generated due to the formation of a lower metal line.

An R color color filter is formed on the first overcoating layer OCL1. As is well known, the color filter forming process is performed by coating a photoresist material having an R color and then performing photolithography processes such as exposure and development.

As shown in FIG. 7B, a color filter of B color is formed on the first overcoating layer OCL1 to be spaced apart from the color filter of R color.

As shown in FIG. 7C, a second overcoating layer OCL2 is formed on the front surface where the color filter of R color and the color filter of B color are formed to reduce the step difference caused by the formation of the two color filters.

Subsequently, a G color filter is formed on the second overcoating layer OCL2 so as not to overlap with the R and B color filters.

Subsequently, the third overcoating layer OCL3 is formed on the G color filter in order to reduce the step difference caused by the formation of the G color filter.

8A to 8C are cross-sectional views illustrating a color filter array forming process of a CMOS image sensor according to another exemplary embodiment of FIG. 6.

8A to 8C correspond to a cross-sectional view of FIG. 4 taken in the c-c 'direction.

As shown in FIG. 8A, a photodiode (not shown), a transistor, and a plurality of metal lines (not shown) are formed on the substrate SUB.

The first overcoat layer OCL1 is formed on the metal line. The first overcoating layer OCL1 is used to prevent defects and to secure process margins when forming the color filter array due to a step generated due to the formation of a lower metal line.

A color filter of B color is formed on the first overcoating layer OCL1.

As is well known, the color filler forming process is performed by coating a photoresist material having a B color and then performing photolithography processes such as exposure and development.

As shown in FIG. 8B, the second overcoating layer OCL2 is formed on the B color filter to reduce the step difference caused by the B color filter formation.

Subsequently, an R color color filter is formed on the second overcoating layer OCL2 to be spaced apart from the B color color filter.

As shown in FIG. 8C, a third overcoating layer OCL3 is formed on the entire surface where the color filter of the R color is formed to reduce the step difference caused by the color filter of the R color.

Subsequently, a G color filter is formed on the third overcoating layer OCL3 so as not to overlap with the R and B color filters.

Subsequently, a fourth overcoating layer OCL4 is formed on the G color filter in order to reduce the step difference caused by the formation of the G color filter.

The present invention made as described above has been found through the embodiment that the black line defects can be reduced by arranging the color filters in a laminated structure such that there is no direct contact between neighboring color filters and disposing a plurality of overcoating layers therebetween. .

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

For example, in the above-described embodiment of the present invention, the CMOS image sensor is taken as an example, but it is also applicable to all image sensors having the light receiving unit and the microlens.

As described above, the present invention can suppress black line defects corresponding to 10% of image sensor defects, thereby improving the yield.

Claims (10)

A first overcoating layer provided on the substrate; A first color filter provided on the first overcoating layer; A second color filter provided on the first overcoating layer to be spaced apart from the first color filter; A second overcoating layer provided on the first color filter and the second color filter; And A third color filter provided on the second overcoating layer so as not to overlap with the first color filter and the second color filter Color filter array of the image sensor comprising a. A first overcoating layer provided on the substrate; A first color filter provided on the first overcoating layer; A second overcoating layer provided on the first color filter; A second color filter provided on the second overcoating layer so as not to overlap with the first color filter; A third overcoating layer provided on the second color filter; And A fourth color filter provided on the third overcoating layer so as not to overlap with the first color filter and the second color filter Color filter array of the image sensor comprising a. The method according to claim 1 or 2, And the first color filter, the second color filter, and the third color filter have a color format of RGB or YMgCy. The method of claim 1, And a third overcoating layer provided on the third color filter. The method of claim 2, And a fourth overcoating layer provided on the third color filter. Forming a first overcoating layer on the substrate; Forming a first color filter on the first overcoating layer; Forming a second color filter on the first overcoating layer to be spaced apart from the first color filter; Forming a second overcoating layer on the first color filter and the second color filter; And Forming a third color filter on the second overcoating layer so as not to overlap with the first color filter and the second color filter; Color filter array forming method of the image sensor comprising a. Forming a first overcoating layer on the substrate; Forming a first color filter on the first overcoating layer; Forming a second overcoating layer on the first color filter; Forming a second color filter on the second overcoating layer so as not to overlap with the first color filter; Forming a third overcoating layer on the second color filter; And Forming a fourth color filter on the third overcoating layer so as not to overlap the first color filter and the second color filter. Color filter array forming method of the image sensor comprising a. The method according to claim 6 or 7, And wherein the first color filter, the second color filter, and the third color filter have a color format of RGB or YMgCy. The method of claim 6, And forming a third overcoating layer on the third color filter. The method of claim 7, wherein And forming a fourth overcoating layer on the third color filter.

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