KR20080060946A - Image sensor and method of manufacturing image sensor - Google Patents

Abstract

An image sensor and a manufacturing method thereof are provided to improve an image quality of a photodiode by preventing microlenses from being attached to each other. An image sensor includes a photodiode structure(100), microlenses(160), and light blocking patterns(150). The photodiode structure is formed in a pixel region of a semiconductor substrate. The photodiode structure generates an electrical signal based on an incident beam. The microlenses are arranged on the photodiode structure. The light blocking patterns are arranged between the microlenses. The photodiode structure includes a photodiode pixel(110), an interlayer dielectric(120), a color filter(130), and a planarization layer(140). The interlayer dielectric is formed on the photodiode pixel. The color filter is formed on the interlayer dielectric corresponding to the respective photodiode pixels. The planarization layer is formed to cover the color filter.

Description

IMAGE SENSOR AND METHOD OF MANUFACTURING IMAGE SENSOR}

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

FIG. 2 is a plan view of the photodiode pixel illustrated in FIG. 1.

3 is a cross-sectional view of the photodiode structure shown in FIG. 1 formed on a semiconductor substrate.

FIG. 4 is a cross-sectional view illustrating coating a light blocking layer on the photodiode structure shown in FIG. 3 and exposing the light blocking layer.

FIG. 5 is a cross-sectional view illustrating a light blocking pattern formed on the photodiode structure shown in FIG. 3.

FIG. 6 is a cross-sectional view illustrating exposure after coating a photoresist film for forming a microlens on the light blocking pattern illustrated in FIG. 5.

FIG. 7 is a cross-sectional view illustrating a photoresist pattern formed between the light blocking patterns illustrated in FIG. 5.

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

9 is a cross-sectional view of the photodiode structure shown in FIG. 8 formed on a semiconductor substrate.

FIG. 10 is a cross-sectional view of a barrier layer formed on the photodiode structure shown in FIG. 9.

FIG. 11 is a cross-sectional view of applying a light blocking layer on the barrier layer illustrated in FIG. 10.

12 is a cross-sectional view of patterning the light blocking layer shown in FIG. 11 to form a light blocking pattern on the barrier layer.

FIG. 13 is a cross-sectional view illustrating exposure after coating a photoresist film for forming a microlens on the light blocking pattern illustrated in FIG. 12.

FIG. 14 is a cross-sectional view illustrating a photoresist pattern formed between the light blocking patterns illustrated in FIG. 12.

The present invention relates to an image sensor and a method for manufacturing the image sensor. More specifically, the present invention relates to an image sensor and a method of manufacturing the image sensor to improve the quality of the image.

In general, an image sensor is defined as a semiconductor device that converts an optical image into an electrical signal. Conventional image sensors are typically a charge coupled device (CCD), CMOS image sensor (CMOS image sensor) and the like.

A general method of manufacturing an image sensor is to form transistors and photodiodes electrically connected to the transistors on a semiconductor substrate, form insulating film structures and wirings on the transistors and photodiodes, and then red, green, and blue on the insulating film structure. To form a color filter consisting of. Here, when the thicknesses of the red, green, and blue color filters formed on the upper surface of the insulating film structure are different from each other, a photosensitive material is coated on the upper surface of the color filter to form a planarization layer, and a photoresist film is applied on the upper surface of the planarization layer. Then, a reflow process is performed to form a microlens that provides light condensed with a photodiode in portions corresponding to the respective color filters.

However, in the image sensor, when a microlens is formed, a gap is generated between the microlenses, and the gap is passed through the gap together with the focused light when sensing the light at the photodiode by passing unfocused light toward the photodiode. There is also a problem of deteriorating the image quality of the grape diode by sensing the light.

Here, in the process of reflowing the photoresist film applied on the upper surface of the planarization layer and baking the reflowed photoresist film, the size of the gap generated between the microlenses is reduced to 0.3 μm or less or completely. Can be removed. However, when the gap generated between the micro lenses is reduced to 0.3 μm or less, defects in which neighboring micro lenses adhere to each other frequently occur in the baking process. As a result, the profile of the microlens is degraded, and the image quality of the photodiode is also degraded.

Therefore, in the conventional image sensor, a gap of about 0.3 μm is generated between the micro lenses.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide an image sensor and a method of manufacturing the image sensor, which improve the image quality of a photodiode by eliminating gaps between microlenses.

An image sensor for realizing the object of the present invention is formed in the pixel region of the semiconductor substrate, the photodiode structure for generating an electrical signal by the incident light, the micro lenses disposed on the photodiode structure and the photo It includes a light blocking pattern disposed between the micro lenses of the diode structure.

In addition, the image sensor is formed in the pixel region of the semiconductor substrate, the photodiode structure for generating an electrical signal by the incident light, the barrier layer disposed on the photodiode structure, the microlenses disposed on the upper surface of the barrier layer And a light blocking pattern disposed between the micro lenses of the upper surface of the barrier layer.

In addition, a method of manufacturing an image sensor for realizing the object of the present invention comprises the steps of forming a photodiode structure for generating an electrical signal by light incident on a pixel region of a semiconductor substrate, the first surface on the upper surface of the photodiode structure Applying a photoresist film and patterning the first photoresist film to form a light blocking pattern between the pixel regions; and applying a second photoresist film to cover the light blocking pattern on the light blocking pattern. And patterning and heat treating the second photoresist film to form a micro lens between the light blocking patterns.

In addition, a method of manufacturing an image sensor may include forming a photodiode structure for generating an electrical signal by light incident on a pixel area of a semiconductor substrate, forming a planarization layer covering an entire upper surface of the photodiode structure, Forming a barrier layer on an upper surface of the planarization layer, depositing a metal thin film on the upper surface of the planarization layer, and patterning the metal thin film to form a light blocking pattern between the pixel regions, and the light blocking pattern Applying a photoresist film to cover the light blocking pattern on the substrate, and patterning and heat treating the photoresist film to form a microlens between the light blocking patterns.

Hereinafter, an image sensor and a method of manufacturing the image sensor according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, which are common in the art. Those skilled in the art will be able to implement the invention in various other forms without departing from the spirit of the invention.

Example  One

Image sensor

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

Referring to FIG. 1, the image sensor 200 according to the present invention includes a photodiode structure 100, a light blocking pattern 150, and a micro lens 160.

The photodiode structure 100 is formed on the semiconductor substrate 10 and generates an electrical signal by incident light. The photodiode structure 100 may include the photodiode pixel 110 formed in the pixel region of the upper surface of the semiconductor substrate 10, the interlayer insulating layer 120 formed on the photodiode pixel 110, and the interlayer insulating layer ( It includes a color filter 130 formed on the 120 and the planarization layer 140 covering the color filter.

FIG. 2 is a plan view of the photodiode pixel illustrated in FIG. 1.

The photodiode pixel 110 will be described in more detail with reference to FIG. 2.

The photodiode pixel 110 includes a photodiode PD, a transfer transistor Tx, a reset transistor Rx, a select transistor Sx, and an access transistor Ax that detects an amount of light.

The transfer transistor Tx and the reset transistor Rx are connected in series to the photodiode PD. The source of the transfer transistor Tx is connected to the photodiode PD, and the drain of the transfer transistor Tx is connected to the source of the reset transistor Sx. A power supply voltage Vdd is applied to the drain of the reset transistor Sx.

The drain of the transfer transistor Tx serves as a floating diffusion (FD). The floating diffusion layer FD is connected to the gate of the select transistor Sx. The select transistor Sx and the access transistor Ax are connected in series. That is, the source of the select transistor Sx and the drain of the access transistor Ax are connected to each other. A power supply voltage Vdd is applied to the drain of the access transistor Ax and the source of the reset transistor Rx. The drain of the select transistor Sx corresponds to the output terminal Out, and the select signal Row is applied to the gate of the select transistor Sx.

Referring back to FIG. 1, the interlayer insulating layer 120 insulates a wiring made of a multilayer, and the wiring includes a photodiode PD, a transfer transistor Tx, a reset transistor Rx, a select transistor Sx, and an access transistor. Ax) and the like are electrically connected to each other to provide a drive signal or output a signal corresponding to the amount of light. Thus, the interlayer insulating film 120 covers and insulates wirings disposed on different layers.

Meanwhile, the color filter 130 is formed to correspond to each photodiode pixel 110 of the upper surface of the interlayer insulating layer 130 to pass only a specific color and block the remaining colors. The color filter 130 having such a function includes a blue color filter 132 passing only visible light in the blue wavelength band, a green color filter 134 passing only visible light in the green wavelength band, and a red color passing only visible light in the red wavelength band. And a filter 134.

For example, visible rays of different wavelengths close to the wavelength bands passed by the blue, green, and red color filters 132, 134, and 136 pass through the blue, green, and red color filters 132, 134, and 136 to mix colors. In order to prevent the thickness of each of the color filters 132, 134, and 136, that is, the thickness from the upper surface of the interlayer insulating layer 120 to the upper surface of each of the color filters 132, 134, and 136 is shown in FIG. 1. As can be formed differently.

Alternatively, although not shown, the thicknesses of the respective color filters measured from the upper surface of the interlayer insulating film to the upper surface of the respective color filters may be the same in order to prevent light loss and to accurately focus the light to the photodiode pixel.

The planarization layer 140 is formed on the upper surface of the color filter 130. In general, the planarization layer 140 is formed when the thicknesses of the blue, green, and red color filters 132, 134, and 136 are different from each other. The steps of the filters 132, 134 and 136 are alleviated or completely eliminated.

As described above, when the thicknesses of the blue, green, and red color filters are the same, it is preferable not to form the planarization layer so as to minimize the loss of light transmitted from the microlens and to focus the microlens accurately on the photodiode pixel. .

The micro lens 160 accurately transmits light to each photodiode pixel 110, and corresponds to the blue, green, and red color filters 132, 134, and 136 of the upper surface of the planarization layer 140. It is formed in a hemispherical shape.

Preferably, the microlens 160 is formed of a positive type photoresist material in which crosslinks of portions exposed to light are broken.

The light blocking pattern 150 is formed between the microlenses 160 of the upper surface of the planarization layer 140, that is, the boundary between the blue color filter 132 and the green color filter 134, the green color filter 134, and the red color. It is formed at a portion corresponding to the boundary of the filter 136 and the boundary of the red color filter 136 and the blue color filter 132. The light blocking pattern 150 formed as described above completely removes a gap that may occur between the microlenses 160, or reduces the gap size to 0.1 μm or less to absorb light leaking between the microlenses 160. Reflects and blocks light. In addition, in the process of forming the microlens 160 serves as a clamp to hold the shape of each microlens 160 to prevent the microlenses 160 adjacent to each other.

Preferably, the light blocking pattern 150 is formed of a negative type photoresist material in which a cross-link is formed in a portion exposed to light as opposed to the positive type photoresist material forming the microlens 160. do.

The thickness from the top surface to the bottom surface of the light blocking pattern 150 is 3000 kPa.

Manufacturing Method of Image Sensor

1 to 7 are plan views and cross-sectional views showing a manufacturing method of an image sensor according to a first embodiment of the present invention.

3 is a cross-sectional view of the photodiode structure shown in FIG. 1 formed on a semiconductor substrate.

Referring to FIG. 3, in order to manufacture the photodiode structure 100, first, a photodiode pixel 110 is formed on the semiconductor substrate 10. Although only three photodiode pixels 110 are shown in the drawing, a plurality of photodiode pixels 110 may be disposed on the semiconductor substrate 10 corresponding to the resolution.

 Referring to FIG. 2, the photodiode pixel 110 includes a photodiode PD, a transfer transistor Tx, a reset transistor Rx, a select transistor Sx, and an access transistor Ax that detects an amount of light. Include.

The transfer transistor Tx and the reset transistor Rx are connected in series to the photodiode PD. The source of the transfer transistor Tx is connected to the photodiode PD, and the drain of the transfer transistor Tx is connected to the source of the reset transistor Rx. A power supply voltage Vdd is applied to the drain of the reset transistor Rx.

The drain of the transfer transistor Tx serves as a floating diffusion (FD). The floating diffusion layer FD is connected to the gate of the select transistor Sx. The select transistor Sx and the access transistor Ax are connected in series. That is, the source of the select transistor Sx and the drain of the access transistor Ax are connected to each other. A power supply voltage Vdd is applied to the drain of the access transistor Ax and the source of the reset transistor Rx. The drain of the select transistor Sx corresponds to the output terminal Out, and the select signal Row is applied to the gate of the select transistor Sx.

When the photodiode pixel 110 having the above-described structure is formed, an interlayer insulating film 120 covering the diode pixel 110 is formed on the semiconductor substrate 10.

Subsequently, a color filter 130 is formed on an upper surface of the interlayer insulating layer 120, and each color filter 130 is formed corresponding to each photodiode pixel 110. In the present embodiment, the color filter 130 includes a blue color filter 132, a green color filter 134, and a red color filter 136.

The blue, green, and red color filters 130 may be formed by applying a photosensitive material including pigments and / or dyes corresponding to the color filter colors on the interlayer insulating layer 120 and patterning them by photo-etching. Can be.

 In the present embodiment, the blue, green, and red color filters 132, 134, and 136 measured from the surface of the interlayer insulating film may have different thicknesses. Alternatively, the thicknesses of the blue, green, and red color filters 132, 134, and 136 measured from the surface of the uppermost interlayer insulating film may be the same.

After the color filter 130 is formed, the planarization layer 140 is formed on the color filter 130 to form the photodiode structure 100. In the present embodiment, the planarization layer 140 has a blue, green and red color filter 132, 134 in order to alleviate the step, especially when the thickness of the blue, green and red color filters 132, 134, 136 are different. , 136) is preferably formed when the thicknesses are different from each other.

FIG. 4 is a cross-sectional view illustrating coating a light blocking layer on the photodiode structure shown in FIG. 3 and exposing the light blocking layer.

Referring to FIG. 4, after the photodiode structure 100 is formed on the semiconductor substrate 10, the light blocking layer 150a is coated by applying a light blocking material to the upper surface of the planarization layer 140 of the photodiode structure 100. ).

Preferably, the light blocking material is formed of a negative type photoresist material in which cross-links are formed in portions exposed to light. The thickness from the top surface to the bottom surface of the light blocking layer 150a is 3000 kPa.

When the light blocking layer 150a is formed, light is applied on the upper portion of the light blocking layer 150a to correspond to the boundary portion of the exposure mask 300, for example, the blue, green, and red color filters 132, 134, and 136. An exposure mask 300 treated with clear tones to pass through is disposed, the light blocking layer 150a is exposed, and then the light blocking layer 150a is developed.

FIG. 5 is a cross-sectional view illustrating a light blocking pattern formed on the photodiode structure shown in FIG. 3.

When the light blocking layer 150a is developed, only the portion of the light blocking layer 150a that reacts with the light to form a cross link remains with the light blocking layer 150a remaining, and the remaining portions are removed. And the light blocking pattern 150 is formed at a portion corresponding to the boundary of the red color filters 132, 134, and 136.

FIG. 6 is a cross-sectional view illustrating exposure after coating a photoresist film for forming a microlens on the light blocking pattern illustrated in FIG. 5.

Referring to FIG. 6, after the light blocking pattern 150 is formed, a photoresist film 160a covering the light blocking pattern 150 is formed.

Preferably, the photoresist film 160a for forming the microlenses has a positive cross-link broken only in a portion exposed to light as opposed to the negative photoresist material in which the light blocking pattern 150 is formed. Type photoresist material. The thickness of the photoresist film 160a is formed to be thicker than the thickness of the light blocking pattern 150 to completely cover the light blocking pattern 150. The thickness of the photoresist film 160a from the top surface to the bottom surface is 4000 Å.

When the photoresist film 160a for forming the microlens is formed, the exposure mask 300, that is, the exposure mask 300 used to expose the light blocking layer is disposed on the photoresist film 160a. The photoresist film 160a is exposed, and the exposed photoresist film 160a is developed.

FIG. 7 is a cross-sectional view illustrating a photoresist pattern formed between the light blocking patterns illustrated in FIG. 5.

When the photoresist film 160a is developed, only a portion of the photoresist film 160a that is cross-linked due to reaction with light is removed and corresponding to the remaining portions, that is, the blue, green, and red color filters 132, 134, and 136. As shown in FIG. 7, the photoresist pattern 160b is formed between the light blocking patterns 150.

Referring to FIG. 1, after the photoresist pattern 160b is formed, a reflow process of heat treating the photoresist pattern 160b at a temperature at which the photoresist pattern 160b is melted is performed. A hemispherical micro lens 160 is formed in the.

If the light blocking pattern 150 is formed at a portion corresponding to the boundary of each color filter 132, 134, 136 before the microlens 160 is formed as in the first embodiment of the present invention, the microlens 160 is formed. The gap generated between them is completely removed, or the gap size is reduced to 0.1 μm or less to absorb or reflect light leaking between the microlenses 160 to block the light. In addition, the reflow process serves as a clamp to hold the shape of each micro lens 160 to prevent the adjacent micro lenses 160 from sticking to each other.

Example  2

Image sensor

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

Referring to FIG. 8, the image sensor 400 according to the present invention includes a photodiode structure 100, a barrier layer 200, a light blocking pattern 210, and a micro lens 220.

The photodiode structure 100 is formed on the semiconductor substrate 10 and generates an electrical signal by incident light. The photodiode structure 100 may include the photodiode pixel 110 formed in the pixel region of the upper surface of the semiconductor substrate 10, the interlayer insulating layer 120 formed on the photodiode pixel 110, and the interlayer insulating layer ( It includes a color filter 130 formed on the 120 and the planarization layer 140 covering the color filter.

The photodiode pixel 110 includes a photodiode PD, a transfer transistor Tx, a reset transistor Rx, a select transistor Sx, and an access transistor Ax that detects an amount of light. As described above, each component constituting the photodiode pixel 110 is the same as the component of the photodiode pixel 110 described in the image sensor of the first embodiment, and thus detailed description thereof will be omitted.

The interlayer insulating layer 120 insulates the wiring made of a multilayer, and the wiring electrically connects the photodiode PD, the transfer transistor Tx, the reset transistor Rx, the select transistor Sx, and the access transistor Ax. It is connected to output a drive signal or a signal corresponding to the amount of light. Thus, the interlayer insulating film 120 covers and insulates wirings disposed on different layers.

Meanwhile, the color filter 130 is formed to correspond to each photodiode pixel 110 of the upper surface of the interlayer insulating layer 130 to pass only a specific color and block the remaining colors. The color filter 130 having such a function includes a blue color filter 132 passing only visible light in the blue wavelength band, a green color filter 134 passing only visible light in the green wavelength band, and a red color passing only visible light in the red wavelength band. And a filter 134.

For example, visible rays of different wavelengths close to the wavelength bands passed by the blue, green, and red color filters 132, 134, and 136 pass through the blue, green, and red color filters 132, 134, and 136 to mix colors. In order to prevent the thickness of each of the color filters 132, 134, and 136, that is, the thickness from the upper surface of the interlayer insulating layer 120 to the upper surface of each of the color filters 132, 134, and 136 is shown in FIG. As can be formed differently.

Alternatively, although not shown, the thicknesses of the respective color filters measured from the upper surface of the interlayer insulating film to the upper surface of the respective color filters may be all the same in order to prevent light loss and to accurately focus light to the photodiode pixel.

The planarization layer 140 is formed on the upper surface of the color filter 130. In general, the planarization layer 140 is formed when the thicknesses of the blue, green, and red color filters 132, 134, and 136 are different from each other. The steps of the filters 132, 134 and 136 are alleviated or completely eliminated.

As described above, when the thicknesses of the blue, green, and red color filters are the same, it is preferable not to form the planarization layer so as to minimize the loss of light transmitted from the microlens and to focus the microlens accurately on the photodiode pixel. .

The barrier layer 200 is disposed on the top surface of the planarization layer 140 to damage the lower layer, that is, the photodiode structure 100, which may be generated in the process of forming the light blocking pattern 210 and the microlens 220. prevent.

In order to minimize the difference in optical refractive index generated between the barrier layer 200 and the microlens 220, the barrier layer 200 should be formed as thin as possible, and if the barrier layer 200 is formed too thin, the photodiode structure Since the damage of the 100 cannot be prevented, the barrier layer 200 has a thickness of about 1000 mm 3.

Preferably, the barrier layer 200 is formed of silicon oxide, for example SiO ₂ .

The micro lens 220 accurately transmits light to each photodiode pixel 110, and corresponds to the blue, green, and red color filters 132, 134, and 136 of the upper surface of the planarization layer 140. It is formed in a hemispherical shape.

Preferably, the microlens 220 is formed of a positive type photoresist material in which the cross link of the portion exposed to light is broken, and the thickness from the highest portion of the upper surface of the microlens to the lower surface of the microlens is 3500 kV. to be.

The light blocking pattern 210 is formed between the micro lenses 220, that is, the boundary between the blue color filter 132 and the green color filter 134, the green color filter 134, and the red color of the upper surface of the planarization layer 140. It is formed at a portion corresponding to the boundary of the filter 136 and the boundary of the red color filter 136 and the blue color filter 132. The light blocking pattern 210 formed as described above completely absorbs or reflects light leaking between the microlenses 220 by eliminating gaps that may occur between the microlenses 220 or reducing the gap size to 0.1 μm or less. To block the light. In addition, in the process of forming the micro lens 220 serves as a clamp to hold the shape of each micro lens 220 to prevent the adjacent micro lenses 220 from sticking to each other.

Preferably, the light blocking pattern 210 is formed of a metal material that reflects and / or absorbs light. Preferably, the light blocking pattern 210 is formed of TiN.

The thickness from the top surface to the bottom surface of the light blocking pattern 150 is 2000 kPa.

Manufacturing Method of Image Sensor

8 to 14 are plan views and cross-sectional views illustrating a method of manufacturing the image sensor according to the second embodiment of the present invention.

9 is a cross-sectional view of the photodiode structure shown in FIG. 8 formed on a semiconductor substrate.

Referring to FIG. 9, in order to manufacture the photodiode structure 100, first, a photodiode pixel 110 is formed on the semiconductor substrate 10. Although only three photodiode pixels 110 are shown in the drawing, a plurality of photodiode pixels 110 may be disposed on the semiconductor substrate 10 corresponding to the resolution. Since the method of forming the photodiode pixel 110 according to the second embodiment of the present invention is the same as the method of forming the photodiode pixel 110 described in the method of manufacturing the image sensor of the first embodiment, a detailed description thereof will be omitted.

 When the photodiode pixel 110 is formed on the semiconductor substrate 10, an interlayer insulating layer 120 covering the diode pixel 110 is formed.

Subsequently, a color filter 130 is formed on an upper surface of the interlayer insulating layer 120, and each color filter 130 is formed corresponding to each photodiode pixel 110. In the present embodiment, the color filter 130 includes a blue color filter 132, a green color filter 134, and a red color filter 136.

The blue, green, and red color filters 130 may be formed by applying a photosensitive material including pigments and / or dyes corresponding to the color filter colors on the interlayer insulating layer 120 and patterning them by photo-etching. have.

 In the present embodiment, the blue, green, and red color filters 132, 134, and 136 measured from the surface of the interlayer insulating film may have different thicknesses. Alternatively, the thicknesses of the blue, green, and red color filters 132, 134, and 136 measured from the surface of the uppermost interlayer insulating film may be the same.

After the color filter 130 is formed, the planarization layer 140 is formed on the color filter 130 to form the photodiode structure 100. In the present embodiment, the planarization layer 140 has a blue, green and red color filter 132, 134 in order to alleviate the step, especially when the thickness of the blue, green and red color filters 132, 134, 136 are different. , 136) is preferably formed when the thicknesses are different from each other.

FIG. 10 is a cross-sectional view of a barrier layer formed on the photodiode structure shown in FIG. 9.

Referring to FIG. 10, after the photodiode structure 100 is formed on the semiconductor substrate 10, to prevent damage to the photodiode structure 100 on the upper surface of the planarization layer 140 of the photodiode structure 100. To form a barrier layer.

In order to minimize the difference in the optical refractive index generated between the barrier layer 200 and the microlens 220, the barrier layer 200 should be formed as thin as possible. When the barrier layer 200 is formed too thin, subsequent steps, That is, since the damage of the photodiode structure 100 cannot be prevented in the process of forming the light blocking pattern 210 and the microlens 220, the barrier layer 200 is formed to have a thickness of about 1000 kHz.

Preferably, the barrier layer 200 is formed of a silicon oxide material, for example, SiO ₂ by a chemical vapor deposition method.

FIG. 11 is a cross-sectional view of applying a light blocking layer on the barrier layer illustrated in FIG. 10.

Referring to FIG. 11, after forming the barrier layer 200, a light blocking material is coated on the entire surface of the barrier layer 200 by chemical vapor deposition to form a light blocking layer 210a.

Preferably, the light blocking material is formed of a metal material that reflects and / or absorbs light. For example, TiN is used. Then, the thickness from the top surface to the bottom surface of the light blocking layer 210a is formed to about 2000 kPa.

12 is a cross-sectional view of patterning the light blocking layer shown in FIG. 11 to form a light blocking pattern on the barrier layer.

Referring to FIG. 12, after the light blocking layer 210a is formed, a photolithography process is performed on the light blocking layer 210a to provide light at a portion corresponding to the boundary of the blue, green, and red color filters 132, 134, and 136. The blocking pattern 210 is formed.

In order to form the light blocking pattern, first, a photoresist film for patterning the light blocking layer 210a is coated on the light blocking layer 200a, and the photoresist film is exposed and developed by using an exposure mask to form a photoresist. Pattern the film. The exposure mask is, for example, a chrome pattern for blocking light corresponding to the boundary portions of the blue, green, and red color filters 132, 134, and 136, and the remaining portions are masks treated with clear tones to transmit light. .

Thereafter, the light blocking layer 210a is etched using the patterned photoresist film as an etching mask. For example, the light blocking layer 210a is etched using a reactive ion etching method. Then, the light blocking layer 210a remains only at the portion corresponding to the boundary of the blue, green, and red color filters 132, 134, and 136, and the remaining portions are etched by the reactive ions, and the blue, green, and red color filters ( The light blocking pattern 210 is formed at a portion corresponding to the boundary of the 132, 134, and 136.

Here, the barrier layer 200 protects the lower layer, that is, the photodiode structure 100 from ions etching the light blocking layer 210a, to prevent the photodiode structure 100 from being damaged.

FIG. 13 is a cross-sectional view illustrating exposure after coating a photoresist film for forming a microlens on the light blocking pattern illustrated in FIG. 12.

Referring to FIG. 13, after the light blocking pattern 210 is formed, a photoresist film 220a covering the light blocking pattern 210 is formed.

Preferably, the photoresist film 220a for forming the microlens is formed of a positive type photoresist material in which cross-links of portions exposed to light are broken. The thickness of the photoresist film 220a is formed to be thicker than the thickness of the light blocking pattern 210 so as to completely cover the light blocking pattern 210. The thickness of the photoresist film 220a from the top surface to the bottom surface is 3000Å.

When the photoresist film 220a for forming the microlens is formed, the boundary of the exposure mask 300, for example, the blue, green, and red color filters 132, 134, and 136, is formed on the photoresist film 220a. After disposing the exposure mask 300 treated with clear tones so as to transmit light in correspondence with the portion, the photoresist film 220a is exposed and the exposed photoresist film 220a is developed.

FIG. 14 is a cross-sectional view illustrating a photoresist pattern formed between the light blocking patterns illustrated in FIG. 12.

When the photoresist film 220a is developed, only a portion of the photoresist film 220a that is cross-linked due to reaction with light is removed and corresponding to the remaining portions, that is, the blue, green, and red color filters 132, 134, and 136. A portion of the photoresist film 220a remains to form the photoresist pattern 220b between the light blocking patterns 210, as shown in FIG. 14. Here, the barrier layer 200 protects the lower layer, that is, the photodiode structure 100 from the etching solution in the process of etching and developing the light blocking layer 210a to prevent the photodiode structure 100 from being damaged.

Referring to FIG. 8, after the photoresist pattern 200b is formed, a reflow process is performed to heat-treat the photoresist pattern 220b at a temperature at which the photoresist pattern 220b is melted. A hemispherical micro lens 220 is formed. The thickness of the microlens thus formed, that is, the thickness from the highest portion of the upper surface of the microlens to the lower surface of the microlens is 3500 kPa.

If the barrier layer is formed before forming the light blocking pattern as in Embodiment 2 of the present invention, the lower layer, that is, the photodiode structure is damaged by the etching material in the process of forming the light blocking pattern and the process of forming the microlens. Can be prevented.

In addition, if the light blocking pattern 150 is formed at a portion corresponding to the boundary of each color filter 132, 134, and 136 before the microlens 160 is formed, a gap generated between the microlenses 160 may be formed. Completely eliminate or reduce the gap size to 0.1 μm or less to absorb or reflect light leaking between the microlenses 160 to block the light. In addition, the reflow process serves as a clamp to hold the shape of each micro lens 160 to prevent the adjacent micro lenses 160 from sticking to each other.

As described in detail above, when the light blocking pattern is formed between the microlenses, light leakage may be prevented between the microlenses, and the defects of the microlenses sticking to each other may be minimized, so that the image quality and image of the photodiode may be minimized. There is an effect that can improve the display quality of the sensor.

Although the detailed description of the present invention has been described with reference to the embodiments of the present invention, those skilled in the art or those skilled in the art will have the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that various modifications and variations can be made in the present invention without departing from the scope of the art.

Claims (9)

A photodiode structure formed in the pixel region of the semiconductor substrate and generating an electrical signal by incident light; Micro lenses disposed on the photodiode structure; And And a light blocking pattern disposed between the micro lenses of the photodiode structure. The method of claim 1, wherein the photodiode structure is A photodiode pixel formed on the semiconductor substrate; An interlayer insulating film formed on the photodiode pixel; A color filter formed on the interlayer insulating layer corresponding to each of the photodiode pixels; And And a planarization layer formed to cover the color filter. The image sensor of claim 1, wherein the light blocking pattern is formed of TiN. Forming a photodiode structure for generating an electrical signal by light incident on the pixel region of the semiconductor substrate; Applying a first photoresist film to an upper surface of the photodiode structure, and patterning the first photoresist film to form a light blocking pattern between the pixel regions; Applying a second photoresist film to cover the light blocking pattern on the light blocking pattern, and patterning and heat treating the second photoresist film to form a microlens between the light blocking patterns. Method of manufacturing the sensor. The method of claim 4, wherein Forming the photodiode structure Forming a photodiode pixel on the semiconductor substrate corresponding to the pixel region; Forming an interlayer insulating film covering the photodiode pixel; Forming a color filter corresponding to each of the photodiode pixels on the interlayer insulating film; And Forming a planarization layer covering the color filter. The method of claim 4, wherein the first photoresist film is of a negative type, and the second photoresist film is of a positive type. The method of claim 4, wherein the mask for patterning the first photoresist film and the mask for patterning the second photoresist film are the same. The method of claim 4, further comprising: forming a planarization layer on the photoresist structure after forming the photoresist structure; Forming a barrier layer on an upper surface of the planarization layer; Depositing a metal thin film on an upper surface of the planarization layer and patterning the metal thin film to form a light blocking pattern between the pixel regions; And Applying a photoresist film to cover the light blocking pattern on the light blocking pattern, and patterning and heat treating the photoresist film to form a microlens between the light blocking patterns. . The method of claim 8, wherein the metal thin film forming the light blocking pattern is TiN.

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