KR100674968B1 - CMOS Image Sensor with Light-Blocking Pattern for Suppressing Cross Torque and Manufacturing Method Thereof - Google Patents

Abstract

A CMOS image sensor having a light blocking pattern for suppressing cross talk and a method of manufacturing the same are provided. The CMOS image sensor of the present invention includes a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating layer is formed on the resultant semiconductor substrate, and a light blocking pattern is formed on the interlayer insulating layer to surround the edge of the photodiode. A flowable oxide film is formed on the interlayer insulating film on which the light blocking pattern is formed. The light blocking pattern absorbs light incident in a square, thereby preventing light from being incident toward an adjacent photodiode, and a region for forming an inner lens in the flowable oxide film is formed by the step of the light blocking pattern.

CMOS image sensor (CIS), inner lens, tungsten

Description

CMOS image sensor having light shielding patterns for suppressing cross talk and method for manufacturing the same

1A is a circuit diagram schematically illustrating a unit pixel of a general CMOS image sensor, and FIG. 1B is a cross-sectional view illustrating a state in which photodiodes and transfer transistors constituting a unit pixel of the CMOS image sensor of FIG. 1A are integrated on a semiconductor substrate.

2 is a plan view illustrating a unit pixel of a CMOS image sensor including a first metal wire made of a light blocking material according to an embodiment of the present invention, and FIGS. 3A to 3D are light blocking according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line III-III ′ of each process to illustrate a method of manufacturing a CMOS image sensor including a metal wiring made of a material.

4 is a cross-sectional view illustrating a method of manufacturing a CMOS image sensor according to another exemplary embodiment of the present invention.

5 is a plan view illustrating a unit pixel of a CMOS image sensor including a light blocking pattern according to another exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along line VI-VI ′ of FIG. 5.

7 through 9 are cross-sectional views of a CMOS image sensor including a light blocking pattern having sidewall slopes according to another embodiment of the present invention.

10 is a cross-sectional view of a CMOS image sensor including a landing pad according to another embodiment of the present invention.

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

100 semiconductor substrate 115 gate electrode 120 photodiode

125: floating diffusion region 140: first metal wiring 142: light blocking pattern

150, 151: inner lens

The present invention relates to a complementary metal oxide semiconductor (CMOS) image sensor and a method of manufacturing the same, and more particularly, to a CMOS image sensor and a method of manufacturing the same for suppressing crosstalk between adjacent pixels.

In general, an image device is a device that converts an optical image into an electrical signal. Such image devices include charge coupled device (CCD) and CMOS image sensors. However, the CCD has a disadvantage in that the driving method is complicated, the manufacturing process is complicated, and a signal processing circuit cannot be integrated into the CCD chip, which makes one-chip difficult. On the other hand, since a CMOS image element can be manufactured by the conventionally available CMOS technology, research and development on the CMOS image sensor which is easy to manufacture is currently progressing.

Such a CMOS image sensor is composed of a plurality of unit pixels. Each unit pixel includes a photodiode 15 that senses light, a transfer transistor 20 that transfers charges generated by the photodiode 15, and stores the transferred charges as illustrated in FIG. 1A. A reset transistor Rx that periodically resets the floating diffusion region FD and a source follower that buffers a signal according to the charge charged in the floating diffusion region FD. follower). The source follower SF is composed of two MOS transistors M1 and R1 connected in series.

FIG. 1B shows a state in which the photodiode 15 and the transfer transistor 20 constituting the unit pixel are integrated in the semiconductor substrate 11. The photodiode 15 formed in the semiconductor substrate 11 in the form of a pn junction is electrically separated by the transfer transistor 20 and the element isolation film 13. The transfer transistor 20 is composed of a gate electrode 21, source and drain regions 22a and 22b as is known, and each of the source and drain regions 22a and 22b is connected to the multi-layer metal wirings 25 and 30. By an external power supply (not shown). At this time, interlayer insulating films 23 and 27 are interposed between the first metal wiring 25 and the semiconductor substrate 11 and between the first metal wiring 25 and the second metal wiring 30, and the transistor 20 is provided. The light blocking film 40 is formed on the resultant. Here, the metal wires 25 and 30 may be made of a material having excellent electrical conductivity and having a light shielding property such as aluminum.

Such a CMOS image sensor is gradually decreasing its pixel area in order to achieve high resolution. Accordingly, there is a problem in that cross talk between adjacent pixels is significantly increased.

The cross talk as described above is caused by the movement of the electrons ⓔ generated in the semiconductor substrate 10 and the light 50 incident in a blind spot due to the photoelectric effect by the light energy. The crosstalk due to the electron movement generated by the photoelectric effect is almost negligible, and in the current CMOS image sensor, the crosstalk caused by the light 50 incident in a square is more severe.

As shown in FIG. 1B, the crosstalk generated by the light incident in the quadrangle is formed by the metal wires 25 and 30 and the light shielding film 40 formed around the photodiode 15. Is generated by being reflected by each other and incident to another adjacent photodiode 15. Such cross talk may cause mixing of data by mixing data between pixels, and may cause color mixing. In particular, when capturing a bright image, all of the surroundings may appear bright. As a result, there is a difficulty in capturing an accurate image.

Accordingly, it is an object of the present invention to provide a CMOS image sensor capable of suppressing cross talk between adjacent pixels.

In addition, another object of the present invention is to provide a method of manufacturing the CMOS image sensor.

In order to achieve the above object of the present invention, the CMOS image sensor of the present invention includes a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating film formed on the semiconductor substrate product is formed, and a light blocking pattern is formed on the interlayer insulating film to surround the edge of the photodiode.

In addition, the CMOS image sensor according to another embodiment of the present invention includes a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating film is formed on the resultant semiconductor substrate, and a light blocking pattern is formed on the interlayer insulating film to surround the edge of the photodiode. A fluid oxide film is formed on the interlayer insulating film on which the light blocking pattern is formed. The flowable oxide film has a depression formed by a step of the light blocking pattern in a region corresponding to the photodiode region.

The CMOS image sensor according to another embodiment of the present invention includes a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating film is formed on the result of the semiconductor substrate, and a metal wiring comprising a first pattern formed on the interlayer insulating film to surround an edge of the photodiode and a second pattern electrically connected to a selected region of the transistor. Is formed. A fluid oxide film having depressions formed in a region corresponding to the photodiode is formed on the interlayer insulating film on which the metal wiring is formed, and an inner lens is formed inside the depressions.

In addition, the CMOS image sensor according to another embodiment of the present invention includes a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating film is formed on the resultant semiconductor substrate, and a light blocking pattern is formed on the interlayer insulating film to surround the edge of the photodiode. A flowable oxide film having depressions formed in a region corresponding to the photodiode is formed on the interlayer insulating film on which the light blocking pattern is formed. An inner lens is formed inside the depression, and a metal wire is formed on the flowable oxide film including the inner lens to be electrically connected to the selected region of the transistor.

The CMOS image sensor according to another embodiment of the present invention includes a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating film having a first conductive stud electrically connected to the selected portion of the transistor is formed on the semiconductor substrate resultant. A light blocking pattern is formed on the interlayer insulating layer so as to surround the edge of the photodiode, and a landing pad electrically connected to the first conductive stud is formed on the same plane as the light blocking pattern. A fluid oxide layer having a recess formed in a region corresponding to the photodiode and a second conductive stud contacting the landing pad is formed on the interlayer insulating layer on which the light blocking pattern is formed, and an inner lens is formed inside the recess. It is. A metal wiring contacting with the second conductive stud is formed on the flowable oxide film including the inner lens.

In addition, a method of manufacturing a CMOS image sensor according to another aspect of the present invention is as follows. First, an interlayer insulating film is formed on a semiconductor substrate on which a photodiode and a transistor are formed. A light blocking pattern is formed on the interlayer insulating layer to surround the edge of the photodiode.

A method of manufacturing a CMOS image sensor according to another embodiment of the present invention is as follows. First, an interlayer insulating film is formed on a semiconductor substrate on which a photodiode and a transistor are formed. A light blocking pattern is formed on the interlayer insulating layer to surround the edge of the photodiode. On the interlayer insulating film on which the light blocking pattern is formed, a flowable oxide film having depressions in a region corresponding to the photodiode is formed.

In addition, a method of manufacturing a CMOS image sensor according to another embodiment of the present invention is as follows. First, an interlayer insulating film is formed over a semiconductor substrate on which a photodiode and a transistor are formed, and a conductive stud is formed in the interlayer insulating film so as to be in electrical contact with a selected portion of the transistor. A metal wire is formed on the interlayer insulating layer to surround the edge of the photodiode and is in electrical contact with the conductive stud, and a fluid oxide layer is formed to have a depression on the interlayer insulating film resultant. Form. In this case, as the metal wiring, one film selected from a tungsten film, a titanium film, a titanium nitride film, and a laminated film of a titanium film and a titanium nitride film may be used.

In addition, a method of manufacturing a CMOS image sensor according to another embodiment of the present invention is as follows. An interlayer insulating film is formed on the semiconductor substrate on which the photodiode and transistor are formed. A light blocking pattern is formed on the interlayer insulating layer so as to surround the edge of the photodiode, and a fluid oxide layer having a depression is formed on the interlayer insulating film resultant. Thereafter, an inner lens is formed in the depression. A metal wiring is formed on the flowable oxide film so as to be electrically connected to the selected portion of the transistor. In this case, as the light blocking pattern, one film selected from a tungsten film, a titanium film, a titanium nitride film, and a laminated film of a titanium film and a titanium nitride film may be used.

According to another aspect of the present invention, a method of manufacturing a CMOS image sensor includes a first conductive stud electrically connected to a selected portion of the transistor on a semiconductor substrate on which a photodiode and a transistor are formed. An interlayer insulating film is formed. A light blocking pattern and a landing pad in contact with the first conductive stud are formed on the interlayer insulating layer to surround the edge of the photodiode. After forming a flowable oxide film having a depression on the resultant interlayer insulating film, an inner lens is formed in the depression. Next, a second conductive stud is formed in the flowable oxide film to be electrically connected to the landing pad. In this case, the light blocking pattern and the landing pad are formed of one film selected from tungsten film, titanium film, titanium nitride film and a laminated film of titanium film and titanium nitride film.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and the like of the elements in the drawings are exaggerated to emphasize a more clear description, and the elements denoted by the same reference numerals in the drawings means the same elements.

The present invention is characterized by forming a light blocking pattern in an area surrounding the edge of the photodiode, thereby preventing crosstalk by blocking reflection of light incident in a square. When the flowable oxide film is formed on the light blocking pattern, the inner lens region may be provided by the step difference of the light blocking pattern. As the inner lens is formed in the inner lens region, the light collecting efficiency of the image sensor may be further improved. The CMOS image sensor having such a feature will be described in more detail with reference to the following examples.

2 is a plan view illustrating a unit pixel of a CMOS image sensor including a first metal wire made of a light blocking material according to an embodiment of the present invention, and FIGS. 3A to 3D are light blocking according to an embodiment of the present invention. A cross-sectional view of each process for explaining a method of manufacturing a CMOS image sensor including a metal wiring made of material. Here, FIG. 2 shows the state formed even to the 1st metal wiring.

First, referring to FIGS. 2 and 3A, the device isolation layer 105 is formed in a known manner so that the active region 102 is defined in the semiconductor substrate 100. The active region 102 may include a photodiode predetermined region 102a and a transistor predetermined region 102b, and the photodiode predetermined region 102a may have a rectangular plate shape that occupies most of a unit pixel. 102b may be in the form of a line extending from a predetermined portion of the photodiode predetermined region 102b.

A gate insulating layer 110 and a conductive layer for a gate electrode, such as a doped polysilicon layer, are deposited on the semiconductor substrate 100 having the active region 102 defined therein. The conductive layer for the gate electrode is patterned to form the gate electrode 115 of the transfer transistor, the gate electrode 116 of the reset transistor, and the gate electrode 117 of the transistor constituting the source follower. As is known, the gate electrode 115 of the transfer transistor can be located at the boundary of the photodiode predetermined region 102a and the transistor predetermined region 102b, and constitutes the gate electrode 116 and the source follower of the reset transistor. The gate electrode 117 of the transistor may be located on the transistor predetermined region 102b, respectively. Spacers 117 may be formed on sidewalls of the gate electrodes 115, 116, and 117 in a known manner.

Next, p-type impurities and n-type impurities are implanted into the photodiode predetermined region 102a on one side of the gate electrode 115 of the transfer transistor to form a photodiode 120 formed of a pn junction. Subsequently, an n-type impurity is implanted into the transistor predetermined region 102b on the other side of the gate electrode 115 of the transfer transistor to form a floating diffusion region 125. Simultaneously with forming the floating diffusion region 125, the source and drain regions 126 and the source and drain regions 127 and 128 of the transistors constituting the source follower may be formed together. In the present embodiment, the photodiode 120 is formed before the floating diffusion region 125, but the photodiode 120 may be formed after the floating diffusion region 125 is formed.

The first interlayer insulating layer 130 is deposited on the resultant of the semiconductor substrate 100. The first interlayer insulating film 130 may be, for example, a silicon oxide film. Next, the first interlayer insulating layer 130 is etched to open the floating diffusion region 125, the gate electrode 115 of the transfer transistor, and the gate electrode 116 of the reset transistor, thereby forming a contact hole 132. . Next, the first conductive stud 135 is formed by filling the conductive layer in the contact hole 132. The first conductive stud 135 may be a conductive material such as a tungsten film or a doped polysilicon film having excellent interlayer embedding properties and excellent heat resistance.

Next, referring to FIG. 3B, a first metal wiring metal film is deposited on the first interlayer insulating layer 130 to a thickness of about 1500 to 2500 μm. It is preferable that the first metal wiring metal film is formed of a conductive material having a melting point of 1000 ° C. or more and excellent heat resistance and a capability of blocking light. As the first metal wiring metal film, for example, a tungsten film W, a titanium film Ti, a titanium nitride film TiN, or a laminated film (Ti / TiN) of a titanium film and a titanium nitride film may be used. Thereafter, the first metal wiring metal film is partially patterned to form a second pattern extending in contact with the first pattern 140a surrounding the edge of the photodiode 120 and the first conductive stud 135. The first metal wiring 140 formed of 140b is formed. The first pattern 140a and the second pattern 140b may be connected to each other, and the second pattern 140b may be electrically connected to the first conductive stud 135 to form a part of the edge of the photodiode 120. It may be formed to wrap. In the present exemplary embodiment, the first pattern 140a constituting the first metal wire 140 may serve to absorb light incident in a square.

As illustrated in FIG. 3C, a fluid oxide layer 145 is deposited on the first interlayer insulating layer 130 on which the first metal wire 140 is formed. As the flowable oxide film 145, for example, a borophosphorus silicate glass (BPSG) film, a phosphorus silicate glass (PSG) film, or a composite film (or a laminated film) of the BPSG film and the PSG film may be used. Next, the flowable oxide film 145 is heat treated at a temperature of 800 ° C to 1000 ° C to reflow. In this case, as the first pattern 140a constituting the first metal wire 140 is formed to surround the edge of the photodiode 120, the flowable oxide film 145 is formed by the step of the first pattern 140a. In particular, the depression 145a is formed in a region corresponding to the photodiode 120. At this time, even if the reflow process of the high-temperature fluidized oxide film 145 is performed, since the first metal wire 140 is formed of a metal film having excellent heat resistance, the shape of the first metal wire 140 does not change.

An insulating film for a lens is deposited on the flowable oxide film 145 having the recessed portion 145a to sufficiently fill the recessed portion 145a. As the insulating film for lenses, an insulating film having a refractive index different from that of the silicon oxide film constituting the flowable oxide film 145 and the interlayer insulating film 130 is preferably used. As the insulating film, for example, a silicon nitride film or a silicon nitride oxide film can be used. Thereafter, the surface of the lens insulating film is chemically mechanically polished by a predetermined thickness to form an inner lens 150. As shown in FIG. 4, the lens insulating layer may be chemically mechanically polished to expose the surface of the flowable oxide layer 145. The inner lens 150 focuses the incident light together with the micro lens (not shown) installed on the image sensor toward the photodiode 120.

As shown in FIG. 3D, a second interlayer insulating layer 155 is deposited on the inner lens 150. Next, the via hole 156 is formed by etching the second interlayer insulating layer 155, the inner lens 150, and the flowable oxide layer 145 so that a predetermined portion of the first metal wire 140 is exposed. The second conductive stud 160 is formed in a known manner so that the via hole 156 is filled. As the second conductive stud 160, for example, a tungsten material having excellent interlayer embedding characteristics may be used. The second metal wire 165 is formed on the second interlayer insulating layer 155 to be in contact with the second conductive stud 160. As the second metal wire 165, a metal film having excellent conductivity, for example, an aluminum film Al or an aluminum alloy film, may be used. A third interlayer insulating layer 170 is formed on the second interlayer insulating layer 155 on which the second metal wiring 165 is formed. In this case, the third interlayer insulating layer 170 may be a planarization layer. Subsequently, a light blocking layer 175 is formed on the third interlayer insulating layer 170 to expose a portion of the photodiode 120. Thereafter, although not shown in the figure, a microlens and a color filter are formed on the light shielding layer 175 to primarily focus incident light.

According to the present embodiment, the first metal wire 120 electrically connected to the transistor constituting the CMOS image sensor is formed of a metal film having excellent heat resistance and light blocking ability, and the first metal wire 120 It is designed to surround the edge of the photodiode 120. As a result, even when light is incident in a square with respect to the surface of the image sensor, the incident light is mostly reflected by the first metal wire 120 without being reflected toward the adjacent photodiode 120, thereby preventing cross talk.

In addition, when the flowable oxide film 145 is formed on the first metal wire 140 and reflowed, the step of the first metal wire 140 surrounding the photodiode 120 may be eliminated without a separate process. Inner lens region is constructed. Such formation of the inner lens can further improve the condensing efficiency of the image sensor.

In the above embodiment, although the light blocking pattern surrounding the edge of the photodiode and the first metal wiring are integrally formed, the light blocking pattern and the first metal wiring may be formed separately. In detail, as shown in FIGS. 5 and 6, as described above, the first interlayer insulating layer 130 is formed, and then a light blocking layer is deposited on the first interlayer insulating layer 130. The light blocking film may be a conductive film, and a film having a high melting point property having a melting point of 1000 ° C. or more, for example, a tungsten film, a titanium film, a titanium nitride film, or a titanium / titanium nitride film may be used. Next, the light blocking film is patterned to surround the edge portion of the photodiode 120 to form a light blocking pattern 142.

The light blocking pattern 142 may have a rectangular cross section as shown in FIG. 6, or may have sloped sidewalls.

For example, the light blocking pattern 142 may have sidewalls having a stepped slope as shown in FIG. 7. The light blocking pattern 142 having the stepped slope is positioned on the first pattern 142a and the first pattern 142a and has a narrower width than the first pattern 142a, as shown in FIG. 7. It may have a second pattern 142b having. The light blocking pattern 142 having the stepped slope may be formed in the following manner. First, a first light blocking layer is deposited on the first interlayer insulating layer 130, and then the first light blocking layer is partially patterned to form a first pattern 142a that surrounds the edge of the photodiode 120. . After depositing a second light blocking film on the first interlayer insulating layer 130 on which the first pattern 142a is formed, the second light blocking film is positioned on the first pattern 142a and narrower than the first pattern 142a. By patterning to have a width, a second pattern 142b is formed. The first light blocking film and the second light blocking film are light blocking materials having excellent high temperature resistance, and preferably, materials having different etching selectivities are different from each other.

In order to form the light blocking pattern 142 having sloped sidewalls, as illustrated in FIG. 8, spacers 143 may be formed on both sidewalls of the light blocking pattern 142. The spacer 143 may be formed of the same material as the light blocking pattern 142 or made of silicon nitride.

In addition, as shown in FIG. 9, the light blocking pattern 142 may obtain a tapered sidewall through taper etching.

The flowable oxide film 145 is deposited on the light blocking pattern 142 formed as described above. As the fluidized oxide film 145, as described above, a BPSG film, a PSG film, or a composite film (laminated film) of a BPSG film and a PSG film may be used. Thereafter, a depression 145a is formed in the flowable oxide film 145 corresponding to the photodiode 120. When the light blocking pattern 142 has no sidewall slope as shown in FIG. 6, the flowable oxide film 145 is reflowed at a temperature of 800 to 1000 ° C. Then, the recessed portion 145a is formed in the flowable oxide film 145 by the step of the light blocking pattern 142.

Meanwhile, when the sidewalls of the light blocking pattern 142 have slopes as shown in FIGS. 7 to 9, the depressions 145a are provided only by the deposition of the flowable oxide film 145 without the high temperature reflow process. Can be. In addition, in order to obtain larger curvature, a reflow process may be implemented as needed.

A lens insulating film is deposited on the flowable oxide film 145 having the recessed portion 145a formed in the above manner to fill the recessed portion 145a, and then the surface of the flowable oxide film 145 is exposed. The inner lens 151 is formed by chemical mechanical polishing as much as possible. At this time, the embodiment of the present invention also removes the lens insulating film by a predetermined thickness during the chemical mechanical polishing step for forming the inner lens as described above.

Next, the floating oxide region 145 and the first interlayer insulating layer 130 are etched to contact the floating diffusion region 125, the gate electrode 115 of the transfer transistor, and a predetermined portion of the gate electrode 116 of the reset transistor. The hole 158 is formed. Next, the first conductive stud 161 is formed in a known manner so that the contact hole 158 is filled. As the first conductive stud 161, a tungsten metal film having excellent interlayer embedding characteristics may be used. Next, a first metal wire 166 is formed on the flowable oxide film 145 to be in electrical contact with the first conductive stud 161. An aluminum film or an aluminum alloy film having excellent conductivity may be used as the first metal wire 166. Since the light blocking pattern 142 of the present exemplary embodiment is positioned on a different plane from the first metal wiring 166, the wiring margin is more than that of the embodiment in which the pattern defining the photodiode 120 and the first metal wiring are simultaneously formed. There is. Accordingly, the light blocking pattern 142 may be formed to have a larger width than the first metal wire 140 defining the photodiode 120 in the embodiment.

Next, a second interlayer insulating film 171 is formed on the flowable oxide film 145 on which the first metal wiring 166 is formed. The second interlayer insulating film 171 may be, for example, a planarized oxide film. Thereafter, the second interlayer insulating layer 171 is etched to form a via hole 172 so that a predetermined portion of the first metal wire 166 is exposed, and then a second conductive stud in the via hole 172 is formed in a known manner. 174). Next, a second metal wire 176 is formed on the second interlayer insulating layer 171 to be in contact with the second conductive stud 174.

According to the present exemplary embodiment, the light blocking pattern 142 and the first metal wiring 166 formed on the edge of the photodiode 120 are formed on different planes. As a result, the width of the light blocking pattern 142 can be increased, whereby more light incident in a square can be blocked. In addition, since the first metal wire 166 is formed after the inner lens is formed, the first metal wire 166 can be formed of a metal film having excellent conductivity characteristics regardless of the melting point, thereby improving signal transmission characteristics. have. In addition, when the light blocking pattern 142 is formed to have a slope on the sidewall surface, the reflow process may be eliminated, or the reflow process may be performed to improve curvature of the inner lens, thereby improving light condensing efficiency. Can be.

10 is a cross-sectional view of a CMOS image sensor for explaining another embodiment of the present invention. Since the present embodiment is the same as the above-described embodiments and the process of forming the first interlayer insulating film 130, only the subsequent description will be described without the overlapping description.

As shown in FIG. 10, the first interlayer insulating layer is formed on the semiconductor substrate 100, and the floating diffusion region 125, the gate electrode 115 of the transfer transistor, and the gate electrode 116 of the reset transistor are formed. The first interlayer insulating layer 130 is etched to form the contact hole 132 to be opened. Next, the conductive layer is filled in the contact hole 132 to form the first conductive stud 135. Similar to the above-described embodiment, the first conductive stud 135 has excellent interlayer embedding properties, and a conductive material having excellent heat resistance, such as a tungsten film or a doped polysilicon film, may be used.

A light blocking film is formed on the first interlayer insulating film 130. As described above, the light blocking film is preferably a conductive film having excellent high temperature resistance. For example, tungsten, titanium, titanium nitride, or titanium / titanium nitride may be used as the light blocking layer. Next, the light blocking layer is partially patterned to form a landing pad 144 contacting the light blocking pattern 144 and the first conductive stud 135 to surround the photodiode 120. . The landing pad 144, as is known, has a larger area than the first conductive stud 135, thereby preventing misalignment with the lower contact stud (first conductive stud 135) when forming the upper stud. Such landing pad 144 has a local island shape.

In this case, the light blocking pattern 142 and the landing pad 144 may have spacers on the sidewalls as shown in FIG. 8, or the sidewalls may have a tapered shape as shown in FIG. 9.

The flowable oxide layer 145 is deposited on the first interlayer insulating layer 130 on which the light blocking pattern 142 and the landing pad 144 are formed. Next, the flowable oxide film 145 is reflowed at a temperature of 800 to 1000 ° C. to form a recessed portion 145a in a portion of the flowable oxide film 145 corresponding to the photodiode 120. In this case, when the sidewall of the light blocking pattern 142 has a slope, the reflow process may not be performed. Thereafter, the inner lens 151 is formed in the recess 145a in the same manner as described above.

Thereafter, the floating oxide layer 145 and the first interlayer insulating layer 130 are etched to expose the landing pad 144 to form a via hole 158a. Since the landing pad 144 has a relatively large area, it is easy to form the via hole 158a. Next, the second conductive stud 162 is formed in a known manner so that the via hole 158a is filled. As the second conductive stud 162, a tungsten metal film having excellent interlayer embedding characteristics may be used. Subsequently, the subsequent process is the same as the embodiment described above.

As such, by forming the landing pad together with the light blocking pattern, misalignment between the first conductive stud 135 and the second conductive stud 162 can be prevented. In addition, by forming a conductive stud in each of the flowable oxide film 145 and the inside of the first interlayer insulating film 130, a large aspect ratio penetrates the flowable oxide film 145 and the first interlayer insulating film 130. There is no need to fabricate a contact hole, and the effort of embedding a conductive material in a contact hole having such a large aspect ratio can be reduced.

As described above in detail, according to the present invention, a light blocking pattern having heat resistance is formed on the outer side of the photodiode constituting the CMOS image sensor. As a result, light incident in a rectangular direction can be blocked without being reflected toward the upper metal wiring to prevent cross talk with adjacent pixels.

In addition, a flowable oxide film is formed on the resultant on which the light blocking pattern is formed, and the flowable oxide film is reflowed to form an inner lens region in a region corresponding to the photodiode by the step difference of the light blocking pattern. When the inner lens is formed in the inner lens region, the light collecting efficiency of the CMOS image element is further improved, and thus the sensitivity of the image sensor can be improved.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. Do.

Claims (50)

A semiconductor substrate on which photodiodes and transistors are formed; An interlayer insulating film formed on the semiconductor substrate product; And And a light blocking pattern formed on the interlayer insulating layer to surround edges of the photodiode and absorbing light. The CMOS image sensor according to claim 1, wherein the light blocking pattern is one film selected from tungsten film, titanium film, titanium nitride film, and a laminated film of titanium film and titanium nitride film. The CMOS image sensor of claim 1, wherein the light blocking pattern is floating. The CMOS image sensor of claim 1, wherein an electrical signal is applied to the light blocking pattern. A semiconductor substrate on which photodiodes and transistors are formed; An interlayer insulating film formed on the semiconductor substrate product; A light blocking pattern formed on the interlayer insulating layer to surround an edge of the photodiode; A fluid oxide film formed on the interlayer insulating film on which the light blocking pattern is formed, and having a depression formed in a region corresponding to the photodiode by a step of the light blocking pattern; And CMOS image sensor including an inner lens formed inside the depression. The CMOS image sensor of claim 5, wherein the light blocking pattern is a material having a melting point of 1000 ° C. or higher. 7. The CMOS image sensor according to claim 6, wherein the light blocking pattern is one film selected from tungsten film, titanium film, titanium nitride film and a laminated film of titanium film and titanium nitride film. 6. The CMOS image sensor of claim 5, wherein the sidewalls of the light blocking pattern have a slope. The method of claim 8, wherein the light blocking pattern comprises: a first pattern formed on the interlayer insulating film; And a second pattern formed on the first pattern and having a narrower width than the first pattern. The CMOS image sensor of claim 8, wherein a spacer is further formed on a sidewall of the light blocking pattern. delete The CMOS image sensor according to claim 5, wherein the inner lens is formed of a film having a refractive index different from that of the flowable oxide film and the interlayer insulating film. 6. The semiconductor device of claim 5, further comprising a metal wire electrically connected to the selected portion of the transistor between the flowable oxide film and the interlayer insulating film, wherein the metal wire is electrically connected to the light blocking pattern. CMOS image sensor. The CMOS image sensor of claim 13, wherein the metal wire is formed of the same material as the light blocking pattern. 6. The CMOS image sensor as claimed in claim 5, further comprising a metal wiring on top of the flowable oxide film, the metal wiring being electrically connected to a selected portion of the transistor, wherein the metal wiring is electrically insulated from the light blocking pattern. 6. The device of claim 5, further comprising: a first conductive stud formed in said interlayer insulating film and electrically connected to a selected portion of the transistor; A landing pad formed on the interlayer insulating layer to be in contact with the first conductive stud; A second conductive stud formed in said flowable oxide film and electrically connected to said landing pad; And Further comprising a metal wiring formed on the second conductive stud, And the landing pad is spaced apart from the light blocking pattern and formed of the same material. 6. The CMOS image sensor of claim 5, wherein the flowable oxide film is one selected from a borophosphorus silicate glass (BPSG) film, a phosphorus silicate glass (PSG) film, and a composite film of the BPSG film and the PSG film. A semiconductor substrate on which photodiodes and transistors are formed; An interlayer insulating film formed on the semiconductor substrate product; A metal line formed on the interlayer insulating layer, the metal line including a first pattern formed to surround an edge of the photodiode and a second pattern electrically connected to a selected region of the transistor; A flowable oxide film formed on the interlayer insulating film on which the metal wiring is formed, and having a depression formed in a region corresponding to the photodiode; And CMOS image sensor including an inner lens formed inside the depression. A semiconductor substrate on which photodiodes and transistors are formed; An interlayer insulating film formed on the semiconductor substrate product; A light blocking pattern formed on the interlayer insulating layer and surrounding the edge of the photodiode; A flowable oxide film formed on the interlayer insulating film on which the light blocking pattern is formed, and having a depression formed in a region corresponding to the photodiode; An inner lens formed inside the depression; And And a metal wire formed on the flowable oxide film including the inner lens and electrically connected to the selected region of the transistor. A semiconductor substrate on which photodiodes and transistors are formed; An interlayer insulating film formed on the semiconductor substrate resultant and having a first conductive stud electrically connected to a selected portion of the transistor; A light blocking pattern formed on the interlayer insulating layer and surrounding the edge of the photodiode; A landing pad formed on the interlayer insulating layer and electrically connected to the first conductive stud; A flowable oxide film formed on the interlayer insulating film on which the light blocking pattern is formed, and having a depression formed in a region corresponding to the photodiode and a second conductive stud contacting the landing pad; An inner lens formed inside the depression; And And a metal wire formed on the flowable oxide film including the inner lens and in contact with the second conductive stud. Providing a semiconductor substrate having a photodiode and a transistor formed thereon; Forming an interlayer insulating film on the semiconductor substrate; And And forming a light blocking pattern on the interlayer insulating layer to absorb light to surround the edge of the photodiode. 22. The method of claim 21, wherein the light blocking pattern is formed of a tungsten film, a titanium film, a titanium nitride film, or a film selected from a laminate film of a titanium film and a titanium nitride film. 22. The method of claim 21, wherein the light blocking pattern is formed to be electrically connected to a selected region of the transistor. Providing a semiconductor substrate having a photodiode and a transistor formed thereon; Forming an interlayer insulating film on the semiconductor substrate product; Forming a light blocking pattern on the interlayer insulating layer to surround an edge of the photodiode; Forming a flowable oxide film having depressions in a region corresponding to the photodiode on the interlayer insulating film on which the light blocking pattern is formed; And And forming an inner lens in the depression of the flowable oxide film. The method of claim 24, wherein forming the light blocking pattern comprises: Depositing a conductive film on the interlayer insulating film; And And etching the conductive layer to partially enclose the edge of the photodiode. 27. The method of claim 25, wherein the conductive film includes one of tungsten film, titanium film, titanium nitride film, and one film selected from a titanium film and a titanium nitride film. 27. The method of claim 25, further comprising forming a spacer on sidewalls of the remaining conductive film pattern after etching the conductive film. 27. The method of claim 25, wherein in the etching of the conductive film, the conductive film is tapered etched. The method of claim 24, wherein forming the light blocking pattern comprises: Forming a first conductive film on the interlayer insulating film; Etching a portion of the first film to form a first pattern; Forming a second conductive film on the interlayer insulating film on which the first pattern is formed; And And etching a predetermined portion of the second conductive layer to form a second pattern having a narrower width than the first pattern on the first pattern. 30. The method of claim 29, wherein the first and second conductive films are one film selected from tungsten film, titanium film, titanium nitride film, and a laminated film of titanium film and titanium nitride film. 26. The method of claim 24 or 25, wherein forming a flowable oxide film having the depression, Depositing a film selected from a BPSG film, a PSG film, and a composite film of a BPSG film and a PSG film on the interlayer insulating film on which the light blocking pattern is formed; And And reflowing the selected film at a temperature of 800 to 1000 ° C. 30. The method of claim 24, 27, 28, 29, 29, 29, 29 or 29, wherein the forming of the fluidized oxide film having the depression, the BPSG film, PSG film on the interlayer insulating film formed with the light blocking pattern And depositing one film selected from a composite film of a BPSG film and a PSG film. delete The method of claim 24, wherein forming the inner lens comprises: Depositing an insulating film for a lens such that the depression is buried on the flowable oxide film; And And chemically polishing the lens insulating film by a predetermined thickness. 35. The method of claim 34, wherein the lens insulating film is formed of a film having a refractive index different from that of the flowable oxide film and the interlayer insulating film. 35. The method of claim 34, wherein chemical mechanical polishing of the insulating film for the lens comprises chemical mechanical polishing of the insulating film for the lens to expose the surface of the flowable oxide film. 25. The method of claim 24, further comprising forming a metal line electrically connected to a selected portion of the transistor at the same time as forming the light blocking pattern. 25. The method of claim 24, further comprising, after forming the inner lens, forming a metal wire electrically connected to the selected portion of the transistor. 25. The CMOS device of claim 24, further comprising forming a conductive stud in the interlayer insulating film, the conductive stud electrically connected to the selected portion of the transistor, between the forming the interlayer insulating film and the forming the light blocking pattern. Method of manufacturing an image sensor. 40. The method of claim 39, further comprising forming a landing pad in contact with the conductive stud simultaneously with forming the light blocking pattern. Providing a semiconductor substrate having a photodiode and a transistor formed thereon; Forming an interlayer insulating film on the semiconductor substrate product; Forming a conductive stud in the interlayer dielectric to be in electrical contact with a selected portion of the transistor; Forming a metal wire on the interlayer insulating layer, the metal wire being in electrical contact with the conductive stud while surrounding the edge of the photodiode; Forming a flowable oxide film having a depression on the interlayer insulating film resultant; And Forming an inner lens in the depression, The metal wiring is a tungsten film, a titanium film, a titanium nitride film and a method of manufacturing a CMOS image sensor, characterized in that formed of one film selected from a laminated film of a titanium film and a titanium nitride film. Providing a semiconductor substrate having a photodiode and a transistor formed thereon; Forming an interlayer insulating film on the semiconductor substrate product; Forming a light blocking pattern on the interlayer insulating layer to surround an edge of the photodiode; Forming a flowable oxide film having a depression on the interlayer insulating film resultant; Forming an inner lens on the recessed portion; And Forming a metal wiring over the flowable oxide film so as to be electrically connected to the selected portion of the transistor, The light blocking pattern may be formed of a tungsten film, a titanium film, a titanium nitride film, and one film selected from a laminated film of a titanium film and a titanium nitride film. Providing a semiconductor substrate having a photodiode and a transistor formed thereon; Forming an interlayer insulating film on the semiconductor substrate product, the interlayer insulating film including a first conductive stud electrically connected to the selected portion of the transistor; Forming a light blocking pattern and a landing pad in contact with the first conductive stud so as to surround an edge of the photodiode on the interlayer insulating film; Forming a flowable oxide film having a depression on the interlayer insulating film resultant; Forming an inner lens on the recessed portion; And Forming a second conductive stud in the flowable oxide film, the second conductive stud being electrically connected to the landing pad, The light blocking pattern and the landing pad are formed of a tungsten film, a titanium film, a titanium nitride film and one film selected from a laminated film of a titanium film and a titanium nitride film. The method of claim 18, And the depression is formed by a step of the light blocking pattern. The method of claim 19, And the depression is formed by a step of the light blocking pattern. The method of claim 20, And the depression is formed by a step of the light blocking pattern. The method of claim 24, And the recessed portion is formed by a step of the light blocking pattern. 42. The method of claim 41 wherein And the recessed portion is formed by a step of the light blocking pattern. The method of claim 42, And the recessed portion is formed by a step of the light blocking pattern. The method of claim 43, And the recessed portion is formed by a step of the light blocking pattern.

Images