image sensor and method for manufacturing the same

专利摘要:
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor and a method of manufacturing the same, which form a color image by separating a desired color by an optical sensor using spectroscopy using multiple slits without forming a color filter. A plurality of photosensitive devices, a transparent insulating film formed on the front surface of the substrate including the photosensitive device, and formed at regular intervals on the transparent insulating film to prevent light from being incident into an area other than the photosensitive sensor. A plurality of light shielding layers formed on the plurality of light shielding layers and a plurality of slits formed on the transparent insulating film between the light shielding layers to transmit visible light, and a plurality of color separations of the visible light passing through the multiple slits in the transparent insulating film. It is characterized by including a metal compound.
公开号:KR20020039454A
申请号:KR1020000069279
申请日:2000-11-21
公开日:2002-05-27
发明作者:유석빈
申请人:박종섭；주식회사 하이닉스반도체；
IPC主号:

专利说明:

Image sensor and method for manufacturing the same
[11] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor, and more particularly, to an image sensor suitable for realizing a color image using the principle of multiple slits and a manufacturing method thereof.
[12] In general, an image sensor is a semiconductor device that converts an optical image into an electrical signal, and is divided into a charge coupled device (CCD) image sensor and a complementary metal oxide silicon (CMOS) image sensor.
[13] First, a CCD image sensor is a device in which charge carriers are stored and transported in a capacitor while individual MOS capacitors are in close proximity to each other.
[14] The CMOS image sensor uses a CMOS technology that uses a control circuit and a signal processing circuit as peripheral circuits to make MOS transistors as many as the number of pixels, and uses a switching method of sequentially detecting the output using the CMOS image sensor. It is an element to employ | adopt.
[15] To date, most CCDs developed and used for image pickup devices are driven using high voltage (+ 15V) and -9V, compared to CMOS (Complementary Metal Oxide Semiconductor) circuits. Since it is similar to the process of implementing a bipolar transistor, there is a problem that the process cost is higher than that of a CMOS process.
[16] In order to solve such a problem, research and production of a CMOS image sensor have been made to implement an imaging device in a CMOS process capable of low voltage operation, low power consumption, and low process cost.
[17] Current CMOS image sensors require much research and development due to problems in terms of image quality, although they can be applied to the manufacturing process of CMOS transistors that can be processed very finely.
[18] Hereinafter, a manufacturing method of a conventional image sensor and a color filter will be described with reference to the accompanying drawings.
[19] 1 is a block diagram showing a conventional CMOS or CCD image sensor.
[20] As shown in FIG. 1, a substrate including a plurality of light sensing elements (B, G, R) 12 formed at regular intervals on the substrate 11 to realize color, and the light sensing element 12. The transparent insulating film 13 formed on the entire surface of the layer 11 and the transparent insulating film 13 are formed on the transparent insulating film 13 so as to correspond to the position of each light sensing element 12 on the transparent insulating film 13 to provide transmittance characteristics for each color. A color filter 14 having is formed.
[21] In this case, a metallic compound 15 serving as a color separator is formed in the transparent insulating layer 13 between the light sensing element 12 and the color filter 14, and is formed at one end of the substrate 11. A portion of the surface of the formed metal compound 15 is exposed to form a pad region 16 which is then package bonded by wire bonding.
[22] Typically, the light sensing element 12 is formed of a photo gate or photodiode, the light shielding layer 15 is formed of a metal layer, and the transparent insulating layer 13 uses a silicon oxide thin film.
[23] On the other hand, there are a number of processes for forming the color filter 14, of which a method using a photosensitive photoresist including a dye is common.
[24] That is, FIGS. 2A to 2C are process cross-sectional views illustrating a conventional method for manufacturing a color filter.
[25] As shown in FIG. 2A, after the first photosensitive photoresist 22 having a blue color is coated on the substrate 21 on which the light sensing sensor, the transparent insulating film, and the metal detector are formed, an exposure and development process is performed. The first photosensitive photoresist 22 is patterned.
[26] As shown in FIG. 2B, a second photosensitive photoresist 23 having a green color is coated on the entire surface including the first photosensitive photoresist 22, and then the first photosensitive photosensitive film is exposed and developed. The second photosensitive photoresist 23 is patterned to be formed on one side of the photoresist 22.
[27] As shown in FIG. 2C, after the third photosensitive photoresist 24 having red color is applied to the entire surface including the first and second photosensitive photoresists 22 and 23, an exposure and development process is performed. The third photosensitive photoresist 24 is patterned to be formed between the first photosensitive photoresist 22 and the second photosensitive photoresist 23.
[28] However, the conventional method of manufacturing the image sensor and the color filter as described above has the following problems.
[29] First, the process is very complicated by applying a photosensitive photoresist having red, blue, and green colors at each step and then patterning them in sequence.
[30] Second, due to the coating characteristics of each photosensitive photoresist during the process, the second and subsequent color patterns have a step difference in thickness due to the color pattern step formed at the lower part thereof, and the third pattern has a flattening phenomenon, causing a severe thickness difference, resulting in uniform color transmittance. Can't get it.
[31] Third, the developer is contacted three times with the metal compound partially exposed to the pad region for forming the wire bonding, and the corrosion phenomenon occurs, and the heavy metal component included to make the color causes environmental problems.
[32] The present invention has been made to solve the above-mentioned problems, and the image sensor and the image sensor to implement a color image by separating the desired color by a light sensing sensor by spectroscopy using multiple slits without forming a color filter and its The purpose is to provide a manufacturing method.
[1] 1 is a block diagram showing a conventional CMOS or CCD image sensor
[2] 2A to 2C are cross-sectional views illustrating a method of forming a color filter of a conventional image sensor.
[3] 3A shows diffraction of light through a single slit
[4] 3B shows diffraction of light through multiple slits
[5] 4 is a block diagram showing an image sensor according to the present invention
[6] 5a to 5e is a cross-sectional view showing a method for forming multiple slits according to the present invention
[7] Explanation of symbols for the main parts of the drawings
[8] 41 substrate 42 photosensitive device
[9] 43: transparent insulating film 44: light shielding layer
[10] 45: multiple slits 46: metal compound
[33] The image sensor according to the present invention for achieving the above object is a plurality of light sensing element formed at a predetermined interval on the substrate, a transparent insulating film formed on the front surface of the substrate including the light sensing element, the transparent insulating film A plurality of light shielding layers formed on the transparent insulating film between the plurality of light shielding layers formed at regular intervals to prevent light from being incident to areas other than the photosensitive sensor, and between the light shielding layers and transmitting visible light And a plurality of metal compounds formed in the transparent insulating film to color-separate the visible light passing through the multiple slits.
[34] In addition, the manufacturing method of the image sensor according to the present invention for achieving the above object comprises the steps of forming a light shielding layer on the front surface of the semiconductor substrate formed with a plurality of light sensing sensors, a transparent insulating film, a metal compound, the light shielding Forming an oxide film and a nitride film sequentially on the layer, applying and patterning a photoresist on the nitride film, reducing the side width of the patterned photoresist, and using the photoresist having the reduced side width as a mask. Selectively removing the nitride film to form a nitride film pattern, forming oxide sidewalls on both sides of the nitride film pattern, removing the nitride film pattern, and using the oxide sidewall as a mask for the light. And selectively removing the shielding layer to form multiple slits. The.
[35] Hereinafter, an image sensor and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.
[36] 3A is a diagram showing diffraction of light through a single slit, and FIG. 3B is a diagram showing diffraction of light through a multiple slit.
[37] As shown in FIG. 3A, when the plane wave laser light 31 is incident perpendicularly to the single slit 32, the slit 32 becomes an obstacle, and thus the laser light is deformed and transmitted to the rear portion blocked by the slit 32. .
[38] That is, the slit 32 deforms the laser beam which is a plane wave, and outputs a spherical wave.
[39] Diffraction, on the other hand, is a characteristic phenomenon of waves that occur when the waves are deformed by obstacles.
[40] As shown in FIG. 3B, the light passing through the multiple slits 32 having the interval “d” of the slits 32 is diffracted if the relationship is expressed according to the wavelength.
[41] (d is the slit interval, θ is the diffraction angle, λ is the wavelength)
[42] Therefore, the longer the wavelength in the interval between the predetermined slit 32, the larger the diffraction angle is bent relatively much. Since the diffraction angle varies depending on the length of each wavelength, the light is separated into three primary colors, red (wavelength: 600 to 650 nm), green (wavelength: 500 to 550 nm), and blue (wavelength: 400 to 450 nm). It becomes possible.
[43] By using the same principle as shown in FIG. 4, if multiple slits are formed on the top of the sensor unit, three primary colors of red, blue, and green can be detected without a color filter pattern. .
[44] That is, Figure 4 is a block diagram showing an image sensor according to the present invention.
[45] As shown in FIG. 4, a plurality of photosensitive elements (R, G, B) 42 formed at regular intervals on the substrate 41 and a substrate 41 including the photosensitive elements 42 are provided. A plurality of light shields formed on the transparent insulating film 43 formed on the entire surface and formed at regular intervals on the transparent insulating film 43 to prevent visible light from entering the area other than the light sensing sensor 42. A multiple slit 45 formed on the transparent insulating film 43 between the layer 44 and the light shielding layer 44 to transmit visible light, and formed in the transparent insulating film 43 to form the multiple It consists of a plurality of metal compounds 46 which color separate the visible light passing through the slit 45.
[46] Here, the light shielding layer 44 and the multiple slits 45 use a metal such as an aluminum film.
[47] Meanwhile, a method of forming the multiple slits 45 formed between the light shielding layers 44 as described above will be described below.
[48] First, if the slit interval "d" becomes small when the wavelength is constant, the diffraction angle can be increased so that the resolution can be increased. The distance between the exposure fixed image slits to date is about 0.25 μm, and in order to further increase the resolution, fine slits are formed as shown in FIGS. 5 to 5 to form multiple slits.
[49] 5A to 5E are process cross-sectional views illustrating a method of forming multiple slits according to the present invention.
[50] As shown in FIG. 5A, an oxide film 52 is formed to a thickness of about 200 μs on a light turn layer (for example, an aluminum film) 51 on which multiple slits are to be formed, and a nitride film 53 is formed on the oxide film 52. ) To 1000 ~ 4000Å (preferably about 2000Å) thickness.
[51] Subsequently, the photoresist 54 is applied onto the nitride film 53, and then the photoresist 54 is patterned by exposure and development processes.
[52] As shown in FIG. 5B, the side width of the patterned photoresist 54 is reduced by a process using wet or plasma.
[53] At this time, the wet may be any solution that is acceptable, but preferably a developer may be used, and when plasma is used, any gas plasma capable of reducing the side may be used, but preferably an oxygen plasma is used.
[54] In addition, in order to reduce the width of the side surface of the patterned photoresist 54, a method of reducing using UV or an oven may be used.
[55] As shown in FIG. 5C, the nitride film 53 is selectively removed using the photoresist 54 having the reduced side width as a mask to form the nitride film pattern 53a.
[56] As shown in FIG. 5D, the photoresist 54 is removed, an oxide film is deposited on the entire surface including the nitride film pattern 53a, and then both sides of the nitride film pattern 53a are formed through blank kit etching on the entire surface. An oxide film sidewall 55 is formed on the substrate.
[57] Since the thickness of the oxide film used as the oxide film sidewall 55 is an element for adjusting the fine line width, the oxide film is formed to match the length of the nitride film pattern 53a.
[58] As illustrated in FIG. 5E, the nitride layer pattern 53a is selectively wet etched using a phosphoric acid (H ₃ PO ₄ ) solution or the like.
[59] Subsequently, although not shown in the drawing, the light shielding layer 51 is selectively removed using the oxide film side 55 as a mask to form a multi-sillet as shown in FIG. 4.
[60] As described above, the image sensor and its manufacturing method according to the present invention have the following effects.
[61] First, manufacturing cost can be reduced by omitting an expensive color filter process step on the image sensor.
[62] Second, uniform color can be obtained without a difference in thickness caused by a color filter process on the image sensor or a color change caused by a non-uniform film.
[63] Third, since there is no color filter process step on the image sensor, it is possible to prevent corrosion of the pad region for wire bonding formation occurring during the color filter process.
[64] Fourth, since there is no color filter that is weak in heat on the image sensor, there is no restriction of the heat process (100 ° C. or more) necessary for the package process.
[65] Fifth, the conventional image sensor is a method of passing only the desired portion of all wavelengths, so the efficiency can not be more than 33%, but the color separation method according to the present invention uses all the light passing through the slit, so the efficiency is increased Can be increased.

权利要求:
Claims (9)
[1" claim-type="Currently amended] A plurality of photosensitive elements formed at regular intervals on the substrate,
A transparent insulating film formed on the entire surface of the substrate including the photosensitive device;
A plurality of light shielding layers formed on the transparent insulating film at regular intervals and formed to prevent light from being incident into a region other than the photosensitive sensor;
Multiple slits formed on the transparent insulating film between the light shielding layers and transmitting visible light;
And a plurality of metal compounds formed in the transparent insulating film to separate color from visible light passing through the multiple slits.
[2" claim-type="Currently amended] The image sensor of claim 1, wherein the light shielding layer and the multiple slits are made of the same material.
[3" claim-type="Currently amended] Forming a light shielding layer on a front surface of the semiconductor substrate on which the plurality of light sensing sensors, the transparent insulating film and the metal compound are formed;
Sequentially forming an oxide film and a nitride film on the light shielding layer;
Applying a photoresist on the nitride film and then patterning the photoresist;
Reducing the side width of the patterned photoresist;
Selectively removing the nitride layer using the photoresist having the reduced side width as a mask to form a nitride layer pattern;
Forming sidewalls of oxide layers on both sides of the nitride layer pattern;
Removing the nitride film pattern;
And removing the light shielding layer selectively using the oxide sidewalls as a mask to form multiple slits.
[4" claim-type="Currently amended] 4. The method of claim 3, wherein said oxide film is formed to about 200 microns thick.
[5" claim-type="Currently amended] 4. The method of claim 3, wherein the nitride film is formed to a thickness of 1000 to 4000 kPa.
[6" claim-type="Currently amended] 4. The method of claim 3, wherein the side width of the patterned photoresist is reduced by using wet or plasma.
[7" claim-type="Currently amended] 7. The method of claim 6, wherein the wet method uses a developer.
[8" claim-type="Currently amended] 7. The method of claim 6, wherein the plasma uses an oxygen plasma.
[9" claim-type="Currently amended] The method of claim 3, wherein the nitride layer pattern is removed by wet etching using a phosphoric acid solution or the like.

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同族专利:

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引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

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法律状态:
2000-11-21|Application filed by 박종섭, 주식회사 하이닉스반도체

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2000-11-21|Priority to KR1020000069279A

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2000-11-21|Priority claimed from KR1020000069279A

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2002-05-27|Publication of KR20020039454A

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2002-09-12|Application granted

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2002-09-12|Publication of KR100351910B1

优先权:

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申请号 | 申请日 | 专利标题

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KR1020000069279A|KR100351910B1|2000-11-21|image sensor and method for manufacturing the same|