KR100897814B1 - Semiconductor device and method of fabricating the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device and a method of manufacturing the same, which can improve signal characteristics by reducing signal interference between pixels.

In an image sensor semiconductor device including a light receiving region and a logic region, a semiconductor device according to an embodiment of the present invention may include a plurality of photodiodes formed on a semiconductor substrate of the light receiving region to convert an electric signal into light incident thereto. And a device isolation layer separating each of the plurality of photodiodes, a first insulating layer formed of a transparent material on the entire surface of the semiconductor substrate, and having a first refractive index, and each of the plurality of photodiodes passing through the first insulating layer. A light blocking layer formed of a width of the device isolation layer on the device isolation layer so as to surround the light emitting layer, and having a second refractive index defining a path of light incident on the photodiode, the first insulating layer and the light blocking layer; A second insulating layer formed on the second insulating layer and a metal formed on the second insulating layer and electrically connected to the logic region; And a contact through the line and the first insulating layer to electrically connect the metal line with the other region.

According to an embodiment of the present disclosure, a method of manufacturing a semiconductor device may include forming a plurality of photodiodes and an isolation layer for separating each of the plurality of grape diodes on a semiconductor substrate, and forming a semiconductor having a first refractive index on the semiconductor substrate. Forming a width of the device isolation layer on the device isolation layer by forming an insulating layer and an etching process using the mask on the semiconductor substrate, and enclosing a region of each of the plurality of photodiodes; Forming a plurality of trenches in the trench, filling the trench and forming a light blocking layer of a transparent material having a second refractive index different from the first insulating layer on the entire surface of the semiconductor substrate; Chemical mechanical polishing on the light blocking layer leaving only the portion embedded in the trench And removing step of, by forming a second insulating layer on the semiconductor substrate, characterized by comprising.

The image sensor semiconductor device according to an exemplary embodiment of the present invention defines a propagation path of light incident to each photodiode through a structure of an insulating layer and a light blocking layer having different refractive indices, thereby reducing crosstalk between adjacent pixels. Can be. Through this, the performance of the image sensor can be improved.

Image sensor, crosstalk, light blocking layer

Description

Semiconductor device and method of manufacturing the same {semiconductor device and method of fabricating the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device and a method of manufacturing the same, which can improve signal characteristics by reducing signal interference between pixels.

The image sensor refers to a semiconductor device that converts an optical image into an electrical signal. Device types of image sensors include CCD (Charge Coupled Device) devices and CMOS (Complementary Metal-Oxide-Silicon) devices.

CCD-type device is a device in which charge carriers are stored and transported in capacitors while individual metal-oxide-silicon (MOS) capacitors are located in close proximity to each other, and CMOS-type devices use control circuits and signal processing circuits as peripheral circuits. It is a device that adopts the switching method of making the MOS transistor as many as the number of pixels using the technique used and detecting the output sequentially by using the same.

CCD (charge coupled device) has many disadvantages such as complicated driving method and high power consumption, complicated process due to many steps of mask process, and difficult to realize one chip because signal processing circuit cannot be implemented in CCD chip. There is this.

In order to overcome the disadvantages of the CCD device, the development of a CMOS image sensor using a sub-micron CMOS manufacturing technology has been studied in recent years.

The CMOS image sensor forms an image by forming a photodiode and a MOS transistor in a unit pixel and sequentially detects a signal in a switching method, and implements an image. The CMOS manufacturing technology uses less power and reduces the number of masks in a manufacturing process. Compared with this, manufacturing efficiency can be improved.

In addition, since it is possible to form a single chip in which several signal processing circuits are formed on a chip, it is attracting attention as a next generation image sensor. The image sensor for realizing a color image includes a light detector for generating and accumulating photocharges by receiving light incident from the outside, and a color filter in an array form on the light detector. Color filter arrays (CFAs) generally consist of three types: red, green, and blue.

In addition, the image sensor is composed of a light sensing portion for detecting light and a logic circuit portion for processing the detected light as an electrical signal to make data, and efforts are being made to increase light sensitivity.

In order to increase the optical sensitivity, efforts have been made to increase the fill factor of the area of the light sensing portion of the entire image sensor device. There is a limit.

In addition, in recent years, as the degree of integration of semiconductor devices is increased, a large number of devices are formed in the same area, thereby improving production yield. In this regard, there is a limit to expanding the light sensing area as desired.

1 is a cross-sectional view showing a general image sensor.

The general image sensor 1 shown in FIG. 1 shows only a light receiving area including photodiodes 20a, 20b, and 20c except for a logic area among all image sensors.

Referring to FIG. 1, a general image sensor 1 includes a plurality of photodiodes 20a, 20b, and 20c for converting light incident on the semiconductor substrate 10 into electrical signals, and a plurality of photodiodes 20a. A device isolation layer (STI) 12 for separating each of the semiconductor substrates 20b and 20c, and first and second insulating layers 30 and 32 formed of a transparent material on the entire surface of the semiconductor substrate 10; And a metal line 34 formed on the second insulating layer 32 and electrically connected to a logic region (not shown) and electrically connecting the metal line 34 to another region through the first insulating layer 30. And a contact 36.

In addition, the color filter layer 40 of red (R), blue (B), and green (G) formed on the second insulating layer 32 to correspond to the plurality of photodiodes 20a, 20b, and 20c, and color Microlenses to correspond to the planarization layer 50 formed on the filter layer 40 and the red (R), blue (B), and green (G) color filters of the plurality of color filter layers 40 on the planarization layer 50. 60 is formed.

Here, various transistors and metal wirings are formed in a logic region not shown.

The image sensor 1 according to the general technique configured as described above is colored by color in order to receive red (R), green (G), and blue (B) signals, respectively, on the photodiode 20a, 20b, and 20c areas. The filter layer 40 is formed, and the microlens 60 is formed at the top of the light receiving portion in order to receive more light.

Each of these signals is connected to an image processing circuit made outside the light receiving unit through a plurality of metal lines and recombined into one phase through signal processing.

Recently, with the development of semiconductor technology, technology of 0.18 μm, 0.13 μm, and 0.11 μm or less has been developed, and the size of pixels has been further reduced.

As the size of these pixels decreases, there is a problem that the saturation voltage, sensitivity to light, and the like deteriorate. In particular, a sharp increase in crosstalk between adjacent pixels occurs.

Such crosstalk between adjacent pixels reduces the chromaticity discrimination capability of the pixels, which in turn degrades the performance of the image sensor.

In order to prevent such a crosstalk phenomenon, it is necessary to widen the distance between the photodiodes, which are the light receiving sections in the pixel.

However, when the size of the pixel is fixed, the area of the photodiode must be reduced because the gap cannot be widened, which causes another problem that degrades the saturation voltage characteristic of the image sensor and hinders the high integration of the pixel. .

The image sensor according to the prior art has a problem that the saturation voltage, sensitivity to light, etc. deteriorate as the size of the pixel is smaller, and particularly, a sharp increase in crosstalk between adjacent pixels occurs.

Such crosstalk between adjacent pixels decreases the chromaticity discrimination ability of the pixels, which in turn degrades the performance of the image sensor.

In order to prevent the crosstalk phenomenon, the distance between the photodiodes, which are light-receiving units, in the pixel must be widened. However, when the size of the pixel is fixed, the area of the photodiode must be reduced because the gap cannot be widened, which causes another problem that degrades the saturation voltage characteristic of the image sensor and hinders the high integration of the pixel. .

In order to solve the above problems, the present invention is to provide a semiconductor device and a manufacturing method thereof that can improve the performance of the image sensor by reducing the crosstalk (phenomena) between the adjacent pixels.

In the semiconductor device according to the embodiment of the present invention for achieving the above object is a light sensor region and a logic region, the semiconductor device of the light receiving region is formed on the semiconductor substrate of the light incident to the electric A plurality of photodiodes for converting signals, an isolation layer for separating each of the plurality of photodiodes, a first insulating layer formed of a transparent material on the entire surface of the semiconductor substrate and having a first refractive index, and the first insulating layer A light blocking layer formed of a width of the device isolation layer on the device isolation layer to penetrate each of the plurality of photodiodes, and having a second refractive index defining a path of light incident on the photodiode; A second insulating layer formed on the first insulating layer and the light blocking layer, and on the second insulating layer; It characterized in that the areas with the metal which is electrically connected to the line, passing through the first insulating layer comprises a contact for electrically connecting the other region and the metal line.

In the semiconductor device according to the embodiment, the first refractive index of the first insulating layer has a value of 1.455 to 1.465, and the second refractive index of the light blocking layer has a value of 1.425 to 1.445.

In an embodiment, the semiconductor device may further include a color filter layer and a microlens corresponding to each of the plurality of photodiodes on the semiconductor substrate.

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The semiconductor device according to the embodiment of the present invention is characterized in that the light blocking layer is formed by filling a trench passing through the first insulating layer.

The semiconductor device according to the embodiment of the present invention is characterized in that the refractive index of the second insulating layer is higher than the refractive index of the first insulating layer and the light blocking layer.

According to an embodiment of the present disclosure, a method of preparing a semiconductor device may include forming a plurality of photodiodes and an isolation layer for separating each of the plurality of grape diodes on a semiconductor substrate, and forming a device having a first refractive index on the semiconductor substrate. Forming a width of the device isolation layer on the device isolation layer by forming an insulating layer and an etching process using the mask on the semiconductor substrate, and enclosing a region of each of the plurality of photodiodes; Forming a plurality of trenches in the trench, filling the trench and forming a light blocking layer of a transparent material having a second refractive index different from the first insulating layer on the entire surface of the semiconductor substrate; Chemical mechanical polishing on the light blocking layer leaving only the portion embedded in the trench And removing step of, by forming a second insulating layer on the semiconductor substrate, characterized by comprising.

In the method of manufacturing a semiconductor device according to an embodiment of the present invention, the first refractive index of the first insulating layer has a value of 1.455 to 1.465, and the second refractive index of the light blocking layer is formed to have a value of 1.425 to 1.445. It is characterized by.

The plurality of trenches in the method of manufacturing a semiconductor device according to an embodiment of the present invention may be formed by performing an etching process using a photoresist as a mask.

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A method of manufacturing a semiconductor device according to an embodiment of the present invention is characterized by forming a refractive index of the second insulating layer higher than that of the first insulating layer and the light blocking layer.

The image sensor semiconductor device according to an exemplary embodiment of the present invention defines a propagation path of light incident to each photodiode through a structure of an insulating layer and an optical light blocking layer having different refractive indices, thereby reducing crosstalk between adjacent pixels. It can improve the performance of the image sensor.

In the method of manufacturing a semiconductor device according to an embodiment of the present invention, the insulating layer and the light blocking layer having different refractive indices are formed in a continuous process, compared to the conventional manufacturing method using a metal material that takes a long time for deposition and visual processes. It is possible to improve manufacturing efficiency by reducing manufacturing time and cost.

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.

2 is a cross-sectional view illustrating a semiconductor device according to an embodiment of the present invention.

The image sensor semiconductor device 100 according to the exemplary embodiment of the present invention illustrated in FIG. 2 includes only a light receiving region including photodiodes 120a, 120b, and 120c, which are characteristic elements of the present invention, excluding a logic region among all image sensors. Shown.

Referring to FIG. 2, in the image sensor according to an exemplary embodiment, the semiconductor device 100 may include a plurality of photodiodes 120a, 120b, and 120c for converting an electrical signal into light incident on the semiconductor substrate 110. ) And a device isolation film (STI) 112 for separating each of the photodiodes 120a, 120b, and 120c, and a first insulating layer formed of a transparent material on the entire surface of the semiconductor substrate 110. On the light blocking layer 170 formed through the first insulating layer 130 and surrounding each of the photodiode 120a, 120b, and 120c regions, and on the first insulating layer 130. The second insulating layer 132 formed, the metal line 134 formed in the second insulating layer 32 and electrically connected to a logic region (not shown), and the metal line penetrating through the first insulating layer 130. And a contact 136 for electrically connecting the other region 134 to the other region.

In addition, the color filter layer 140 of red (R), blue (B), and green (G) formed on the second insulating layer 132 to correspond to the plurality of photodiodes 120a, 120b, and 120c, and color Microlenses corresponding to the red (R), blue (B), and green (G) color filters of the planarization layer 150 formed on the filter layer 140 and the plurality of color filter layers 140 on the planarization layer 150. 160 is formed.

Here, various transistors and metal wirings are formed in a logic region (not shown).

In the image sensor semiconductor device 100 according to the exemplary embodiment of the present invention configured as described above, the red (R), green (G), and blue (B) signals are divided on top of the photodiode 120a, 120b, and 120c, respectively. The color filter layer 140 is formed for each color in order to receive the light, and the microlens 160 is formed at the top of the light receiving unit in order to receive more light.

Each signal generated by the photodiodes 120a, 120b, and 120c is connected to an image processing circuit formed outside the light receiving unit through a plurality of metal lines, and recombined into one phase through a signal processing process.

The image sensor semiconductor device 100 according to an exemplary embodiment of the present invention includes a plurality of photodiodes 120a, 120b, and 120c to prevent crosstalk between adjacent pixels, which is generated in the general image sensor 1 illustrated in FIG. 1. A trench that penetrates the first insulating layer 130 to surround the photodiode 120a, 120b, and 120c region on the region, and then has a refractive index different from that of the first insulating layer 130 in the formed trench. To form a light blocking layer 170 using the difference in refractive index between the materials.

Here, the refractive index of the first insulating layer 130 has a value of 1.455 to 1.465 (preferable refractive index is 1.46), and the refractive index of the light blocking layer 170 has a value of 1.425 to 1.445 (preferred refractive index is 1.435).

In more detail, the light incident through the microlens 160 has a unique color light while passing through the color filter layer 140.

The red (R), blue (B), and green (G) color filters of the color filter layer 140 are formed to correspond to the photodiodes 120a, 120b, and 120c formed below. That is, light passing through the green (G) color filter is received by the first photodiode 120a among the plurality of photodiodes 120a, 120b, and 120c, and light passing through the blue (B) color filter is configured by the plurality of photodiodes. The light received by the second photodiode 120b among the diodes 120a, 120b, and 120c and passing through the red (R) color filter is transmitted to the third photodiode 120c among the plurality of photodiodes 120a, 120b, and 120c. Should be received.

However, each pixel is formed adjacent to each other, and light incident at an angle to the microlens 160 travels out of each photodiode 120a, 120b, 120c.

The image sensor semiconductor device 100 according to the embodiment of the present invention forms a light blocking layer 170 formed of a material having a refractive index different from that of the first insulating layer 130 in order to prevent crosstalk between adjacent pixels. As shown in FIG. 2, the difference in refractive index between the first insulating layer 130 and the light blocking layer 170 may change the path of the light propagating out of each photodiode 120a, 120b, 120c. Can be.

Through this, the path of light incident to each photodiode 120a, 120b, or 120c may be defined to reduce crosstalk between adjacent pixels, thereby improving performance of an image sensor.

3A to 3F are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

First, as shown in FIG. 3A, a plurality of photodiodes 120a, 120b, and 120c are formed on the semiconductor substrate 110, and an isolation layer for separating the photodiodes 120a, 120b and 120c from each other ( Shallow Trench Isolation (STI) 112 is formed.

Here, the device isolation layer 112 may be first formed on the semiconductor substrate 110, and then a plurality of photodiodes 120a, 120b, and 120c may be formed later.

Thereafter, a transparent material having a first refractive index is deposited (coated) on the entire surface of the semiconductor substrate 110, and then cured to form a first insulating layer 130. Here, the refractive index of the first insulating layer 130 has a value of 1.455 to 1.465 (preferable refractive index is 1.46).

Thereafter, as shown in FIG. 3B, after forming a photoresist layer on the first insulating layer 130, patterning regions corresponding to each of the plurality of photodiodes 120a, 120b, and 120c are subsequently etched. In the process, a photoresist 180 used as a mask is formed.

Here, the photoresist 180 is patterned such that the light blocking layer 170 illustrated in FIG. 2 formed through a subsequent process surrounds each of the plurality of photodiode 120a, 120b, and 120c regions.

Thereafter, as illustrated in FIG. 3C, an etching process using the photoresist 180 as a mask is performed to surround the regions of each of the photodiodes 120a, 120b, and 120c on the semiconductor substrate 110. A plurality of trenches 172 are formed in layer 130. Each of the plurality of trenches 172 is formed to overlap the device isolation layer 112 to prevent loss of the light receiving area.

Thereafter, as illustrated in FIG. 3D, a transparent material having a second refractive index different from the first refractive index of the first insulating layer 130 is deposited (coated) on the entire surface of the semiconductor substrate 110, and then cured to form a light blocking layer. Form 170. That is, the light blocking layer 170 is embedded in the plurality of trenches 172 formed by etching the first insulating layer 130. Here, the refractive index of the light blocking layer 170 has a value of 1.425 to 1.445 (preferable refractive index is 1.435).

Thereafter, as illustrated in FIG. 3E, the light blocking layer 170 on the semiconductor substrate 110 may be removed by leaving a portion embedded in the trench 172 by performing a chemical mechanical polishing (CMP) process. 1 The insulating layer 130 and the light blocking layer 170 are planarized.

Thereafter, as illustrated in FIG. 3F, an etching process using photolithography and a mask is performed to form a trench in a portion of the first insulating layer 130 and to fill a conductive material (eg, aluminum or copper). Contact 136 is formed. In addition, a metal line 134 is formed on the first insulating layer 130 to be electrically connected to another region not shown on the first insulating layer 130 so as to overlap the contact 136.

Here, the metal line 134 and the contact 136 serve to electrically connect the logic region and the light receiving region, which are not shown.

Thereafter, a transparent material is deposited (coated) on the entire surface of the semiconductor substrate 110, and then cured to form a second insulating layer 132 to planarize the upper layer.

Thereafter, the color filter layer, the planarization layer, and the micro lens are formed to complete the manufacture of the image sensor semiconductor device.

In the foregoing description, the light blocking layer 170 and the second insulating layer 132 have been formed as separate processes.

The light blocking layer 170 may be replaced with the second insulating layer 132 by adjusting the thickness of the light blocking layer 170 that is removed during the process of removing a part of the light blocking layer 170.

When the second insulating layer 132 is separately formed, the refractive index of the second insulating layer 132 is formed of a material higher than that of the first insulation layer 130 and the light blocking layer 170.

In the method of manufacturing the image sensor semiconductor device according to the embodiment of the present invention, the light blocking layer having a refractive index different from that of the first insulating layer 130 formed on the photodiodes 120a, 120b, and 120c through the manufacturing method described above. The 170 may be formed to surround each of the photodiode regions 120a, 120b, and 120c to prevent crosstalk between adjacent pixels.

The manufacturing method of the semiconductor device according to the embodiment of the present invention can reduce the manufacturing process time compared to the conventional manufacturing method of forming the light blocking and reflecting region with an opaque or metallic material.

In the method of manufacturing a semiconductor device according to an embodiment of the present invention, the insulating layer and the light blocking layer having different refractive indices are formed in a continuous process, compared to the conventional manufacturing method using a metal material that takes a long time for deposition and visual processes. It is possible to improve manufacturing efficiency by reducing manufacturing time and cost.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a cross-sectional view showing a general image sensor.

2 is a cross-sectional view illustrating a semiconductor device in accordance with an embodiment of the present invention.

3A to 3F are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1, 100: image sensor 10: semiconductor substrate

20a, 120a: photodiode 12: device isolation film

30, 32, 130, 132: insulating layer 34, 134: metal line

36, 136: contact 40, 140: color filter

50, 150: planarization layer 60, 160: micro lens

170: light blocking layer 180: photoresist

Claims (9)

An image sensor semiconductor device comprising a light receiving region and a logic region, A plurality of photodiodes formed on a semiconductor substrate in the light receiving region and converting light incident on the light into an electrical signal; An isolation layer for separating each of the plurality of photodiodes; A first insulating layer formed of a transparent material on the entire surface of the semiconductor substrate and having a first refractive index; A transparent material having a width of the device isolation layer formed on the device isolation layer so as to surround each of the plurality of photodiodes through the first insulating layer, and having a second refractive index defining a path of light incident on the photodiode. A light blocking layer, A second insulating layer formed on the first insulating layer and the light blocking layer; A metal line formed on the second insulating layer and electrically connected to the logic region; And a contact penetrating the first insulating layer to electrically connect the metal line with another region. The method of claim 1, The first refractive index of the first insulating layer has a value of 1.455 to 1.465, And a second refractive index of the light blocking layer has a value of 1.425 to 1.445. delete The method of claim 2, The light blocking layer is a semiconductor device, characterized in that formed in the trench penetrating the first insulating layer. The method of claim 2, The refractive index of the second insulating layer has a value higher than the refractive index of the first insulating layer and the light blocking layer. Forming a device isolation layer separating the plurality of photodiodes and the plurality of grape diodes on the semiconductor substrate, Forming a first insulating layer having a first refractive index on the semiconductor substrate; Forming a plurality of trenches in the first insulating layer so as to form a width of the device isolation layer on the device isolation layer and enclosing regions of each of the plurality of photodiodes by performing an etching process using the mask on the semiconductor substrate; , Filling the trench and forming a light blocking layer of a transparent material having a second refractive index different from the first insulating layer on the entire surface of the semiconductor substrate; Performing a chemical mechanical polishing process on the semiconductor substrate to remove the light blocking layer leaving only a portion embedded in the trench; And forming a second insulating layer on the semiconductor substrate. The method of claim 6, The first refractive index of the first insulating layer has a value of 1.455 to 1.465, The second refractive index of the light blocking layer is a method of manufacturing a semiconductor device, characterized in that formed to have a value of 1.425 ~ 1.445. delete The method of claim 6, The refractive index of the second insulating layer is formed higher than the refractive index of the first insulating layer and the light blocking layer.

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