KR20100064530A

KR20100064530A - Image sensor and method for manufacturing the image sensor

Info

Publication number: KR20100064530A
Application number: KR1020080123015A
Authority: KR
Inventors: 황종택
Original assignee: 주식회사 동부하이텍
Priority date: 2008-12-05
Filing date: 2008-12-05
Publication date: 2010-06-15

Abstract

The present invention relates to an image sensor and a method of manufacturing the same, comprising: forming a plurality of photodiodes on a semiconductor substrate, forming red, green, and blue color filters to correspond to the photodiodes; Forming a planarization layer on the entire surface of each of the color filter layers, depositing a first low temperature oxide film on the entire surface of the planarization layer, and implanting first ions onto the first low temperature oxide film; Forming a protective film to protect the planarization layer by implanting second ions onto the first low temperature oxide film into which ions are implanted; depositing and patterning a low temperature oxide film on the entire surface of the protective film, Forming a micro lens to correspond.

Description

Image sensor and method for manufacturing the image sensor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to an image sensor and a method of manufacturing the same, which can solve the problem of exfoliation of an oxide micro lens.

An image sensor refers to a semiconductor device that converts an optical image into an electrical signal, and includes a CCD (Charge Coupled Device) device and a CMOS (Complementary Metal-Oxide-Silicon) device. The image sensor is composed of a light receiving area including a photodiode for detecting light and a logic area for processing the detected light into an electrical signal to make data, and efforts are being made to increase light sensitivity.

Hereinafter, the CMOS image sensor according to the related art will be described with reference to the accompanying drawings.

1 is a cross-sectional view showing a CMOS image sensor according to the prior art.

The conventional CMOS image sensor illustrated in FIG. 1 briefly illustrates only a light receiving region including a photodiode, except for a logic region, among all the image sensors.

Referring to FIG. 1, an image sensor includes a semiconductor substrate 10, a plurality of photodiodes 20 formed in an active region of the semiconductor substrate 10, and an entire surface of the semiconductor substrate 10. The interlayer insulating layer 30 formed thereon, the metal wires 33 formed in the interlayer insulating layer 30, the insulating film 40 formed on the interlayer insulating layer 30, the photodiodes 20, The color filter layer 50 and the color filter layer 50 including the color filters 52, 54, and 56 of red (R), green (G), and blue (B) are formed on the insulating film 40. A plurality of micro lenses formed on the planarization layer 60 formed on the planarization layer 60 and corresponding to the red (R), green (G), and blue (B) color filters 52, 54, and 56 on the planarization layer 60. Field 90;

The planarization layer 60 is formed below the micro lenses 90 for uniformity of the micro lenses 90 to be formed on the color filter layer 50 after the color filter layer 50 is formed to express the color color.

When the microlens 90 shown is made of silicon oxide rather than a conventional organic material, the microlens by particles generated when sawing is performed during packaging of a subsequent device ( 90) contamination can be prevented. However, since the oxide material used as the microlens 90 is deposited at a lower temperature (below 200 ° C.), there is a significant amount of pin holes in the film without dense. .

Due to this problem, in the subsequent wet process, chemical penetrates through the oxide microlens 90 to melt the organic material of the lower planarization layer 60 so that the microlens 90 becomes the planarization layer 60. ), There is a problem of peeling.

2A to 2C are photographs taken of a semiconductor substrate, a planarization layer, and a micro lens in a conventional CMOS image sensor. FIG. 2C is an enlarged photograph of region A of FIG. 2B.

Specifically, when the oxide layer 80 is deposited at a low temperature as shown in FIG. 2A to form a microlens, it can be seen that many pinholes exist in the oxide layer 80 implementing the microlens.

As shown in FIGS. 2B and 2C, when the wet process is performed in a later process, the planarization layer 60 is dissolved through the microlens of the oxide layer 80, and the microlens is planarized as in the region B. 60) there is a problem of peeling off.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an image sensor and a method of manufacturing the same, which can solve the problem of exfoliation of an oxide micro lens.

According to another aspect of the present invention, there is provided a method of manufacturing an image sensor. Forming a planarization layer on the front surface of each color filter layer, depositing a first low temperature oxide film on the front surface of the planarization layer, and implanting first ions onto the first low temperature oxide film; Forming a protective film to protect the planarization layer by implanting second ions onto the first low temperature oxide film into which the first ion is implanted; depositing and patterning a low temperature oxide film on the entire surface of the protective film And forming a microlens to correspond to each photodiode.

The image sensor according to the embodiment of the present invention for achieving the above object is a plurality of photo diodes formed on a semiconductor substrate, red, green, blue color filters formed to correspond to the photo diodes, A planarization layer formed on the front surface of the color filter layer, a passivation film formed on the front surface of the planarization layer to protect the planarization layer, and a microlens formed to correspond to each photodiode by depositing and patterning a low temperature oxide film on the front surface of the passivation film. It is characterized by including.

An image sensor and a method of manufacturing the same according to an embodiment of the present invention have the following effects.

After forming the planarization layer on top of the color filter layer and before forming the microlenses, a protective layer is formed on top of the planarization layer by the first step of the germanium implant process and the second step of the plasma nitridation process, thereby The microlens is prevented from penetrating and dissolving the flattening layer, which is an organic material, during the wet process, etc. through the numerous pinholes of the microlens formed of the deposited silicon oxide, and thus the microlens has a flattening layer and a peeling underneath it. It has the effect of solving the problem.

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.

3 is a cross-sectional view of the CMOS image sensor according to an embodiment of the present invention.

Referring to FIG. 3, the image sensor 100 includes a semiconductor substrate 110, a plurality of photodiodes 120 formed in an active region of the semiconductor substrate 110, and a semiconductor substrate 110. The interlayer insulating layer 130 formed on the front surface, the metal wires 133 formed in the interlayer insulating layer 130, the insulating layer 140 formed on the interlayer insulating layer 130, and the photodiodes ( The color filter layer 150 and the color filter layer including the color filters 152, 154, and 156 of red (R), green (G), and blue (B) formed on the insulating layer 140 to correspond to 120. The planarization layer 160 formed on the 150, the passivation layer 166 protecting the planarization layer 160 on the planarization layer 160, and the red (R), green (G), and blue (B) colors. It includes a plurality of micro lenses 190 formed of a low temperature oxide (LTO) to correspond to the filter (152, 154, 156).

The planarization layer 160 is formed below the micro lenses 190 for uniformity of the micro lenses 190 to be formed on the color filter layer 150 after the color filter layer 150 is formed to express the color color. In some cases, it may be omitted.

The passivation layer 166 may be formed in a first step of a germanium implant process on a low temperature oxide film and in a second step of plasma nitridation process on a germanium low temperature oxide film formed using a germanium implant process.

Here, the process conditions of the germanium implant process are carried out with ion implantation energy of 20 to 50 Kev, dose of 5E13 to 7E15 atoms / cm 2, and single wafer type electron beam curing equipment or batch type ( Batch type implant equipment is used.

The plasma nitridation process is performed using nitrogen (N ₂ ) gas in the chamber.

When the protective film 166 formed as described above is subjected to a wet process in a later process, the planarization layer 160 is dissolved through the microlens 190 made of oxide, and the microlens 190 is separated from the planarization layer 160. It is formed to prevent problems.

Thus, by forming a protective layer on top of the planarization layer by the first step of the germanium implant process and the second step of the plasma nitridation process after forming the planarization layer on the color filter layer and before forming the microlens. The microlenses are provided at the lower part of the microlenses formed by silicon oxide deposited at low temperature, thereby preventing the chemicals from penetrating and dissolving the organic planarization during the wet process. It has an effect which can solve the problem of peeling with a layer.

4A to 4G are cross-sectional views illustrating a method of manufacturing the image sensor shown in FIG. 3.

4A to 4G, the photodiode 120, the metal wire 133, the interlayer insulating layer 130, and the insulating layer 140 in FIG. 3 will be omitted.

Referring to FIG. 4A, after forming the color filter layer 150 for expressing the color color on the semiconductor substrate 110, the planarization layer 160 is formed on the color filter layer 150.

The color filter layer 150 includes color filters 152, 154, and 156 of red (R), green (G), and blue (B), and is formed of an acrylic resin or the like. The color filters 152, 154, and 156 of red (R), green (G), and blue (B) are formed at positions corresponding to the photodiode 120 (FIG. 3).

The planarization layer 160 removes the step when the step occurs in the color filters 152, 154, and 156, and may be omitted in some cases.

Subsequently, after depositing the low temperature oxide film 162 on the planarization layer 160 as shown in FIG. 4B, the germanium implant process is performed as shown in FIG. 4C. Here, the low temperature means a temperature of 200 ° C or less.

Specifically, ion implantation energy of 20-50Kev and dose of 5E13-7E15 atoms / cm 2 using a single wafer type electron beam curing device or a batch type implant device. The germanium (Ge) material is doped into the low temperature oxide film 162 under the process conditions of. The low temperature oxide film 162, which is a porous material, has a denser film because germanium ions collide with the low temperature oxide film 162 to remove pores.

Subsequently, a plasma nitridation (Plasma Nitridation) process is performed on the germanium-doped low temperature oxide film 164 as shown in FIG. 4D.

Specifically, plasma treatment is performed on the low-temperature oxide film doped with germanium using nitrogen (N ₂ ) gas. Germanium doped dense low-temperature oxide film has a strong fire resistance because the film quality is solid through the nitriding process.

Thus, the protective film 166 is formed on the low temperature oxide film 162 as shown in FIG. 4F through the first and second steps.

The protective film 166 is formed to a thickness of 200 kPa to 800 kPa.

The passivation layer 166 may prevent the planarization layer 160 from being dissolved by the chemical penetrating through the microlens 190 by a wet process.

Referring to FIG. 4G, microlenses 190 formed of a low temperature oxide film are formed over the passivation layer 166.

Specifically, after depositing a second low temperature oxide film (not shown) on the entire surface of the protective film 166, a photoresist material is applied on the second low temperature oxide film (not shown), and the patterned applied photoresist material is selectively patterned. After that, a hemispherical micro lens pattern (not shown) is formed through a reflow process.

Subsequently, a microlens 190 is formed on the passivation layer 166 so as to correspond to each color filter by etching the microlens pattern (not shown) with a mask.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear 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.

2A to 2C are photographs taken of a semiconductor substrate, a planarization layer, and a micro lens in a conventional CMOS image sensor.

110 substrate 120 photodiode

130: interlayer insulating layer 133: metal wiring

140: insulating film 150: color filter layer

160: planarization layer 166: protective film

190: Micro Lens

Claims

Forming a plurality of photo diodes on the semiconductor substrate,

Forming red, green and blue color filters to correspond to the photodiodes;

Forming a planarization layer on an entire surface of each color filter layer;

Depositing a first low temperature oxide film on the entire surface of the planarization layer, and then implanting first ions onto the first low temperature oxide film;

Forming a protective film to protect the planarization layer by implanting second ions onto the first low temperature oxide film into which the first ions are implanted;

And depositing and patterning a low temperature oxide film on the entire surface of the passivation layer to form a microlens to correspond to each photodiode.

The method of claim 1,

Injecting the first ion,

A method of manufacturing an image sensor characterized in that it proceeds with germanium ions at a process condition of ion implantation energy of 20 to 50 Kev and dose of 5E13 to 7E15 atoms / cm 2.

The method of claim 1,

Injecting the second ion,

Method of manufacturing an image sensor, characterized in that the step of plasma treatment using nitrogen (N ₂ ) gas.

The method of claim 1,

The protective film is a manufacturing method of the image sensor, characterized in that formed in a thickness of 200 ~ 800Å.

A plurality of photo diodes formed on the semiconductor substrate,

Red, green, and blue color filters formed to correspond to the photodiodes;

A planarization layer formed on an entire surface of each of the color filter layers;

A protective film formed on the entire surface of the planarization layer to protect the planarization layer;

And a micro lens formed to correspond to each photodiode by depositing and patterning a low temperature oxide film on the entire surface of the passivation layer.

The method of claim 5,

The protective film is an image sensor, characterized in that formed in a thickness of 200 ~ 800Å.