JPH05326902A - Manufacture of solid-state image sensing device - Google Patents

Abstract

PURPOSE:To obtain a solid-state image sensing device without image nonuniformity and mixed colors by forming an ultraviolet-ray absorbing layer, which is transparent to visible light, on a substrate, on which a plurality of light receiving parts and charge transfer parts are formed, selectively exposing an ultraviolet-ray sensitive film, which is formed on the ultraviolet-ray absorbing layer, to ultraviolet ray, and thereby forming the steep edge part. CONSTITUTION:Light receiving parts 303 comprising photodiodes and charge transfer parts 305 are formed on a silicon substrate 301. A flat film 309, which has the light transmitting property and absorbs (i) ray, is formed on the light receiving parts 303 and the charge transfer parts 305. Then, a dyeing substrate 311 is selectively sensitized and developed with the exposure to the i-line. The pattern corresponding to the first-color picture elements is formed. Intermediate protecting films 315 and 319 having the light transmitting property are further formed. Color filter patterns 317 and 321 for the dyeing in the second color and the third color are obtained. Then, a flat film 323 having the light transmitting property is formed, and micro-lenses 327 is formed. Thus, the color filter pattern having the steep edge part can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid-state image pickup device. In particular, it relates to a method for manufacturing a color filter of a solid-state image pickup device.

[0002]

2. Description of the Related Art Generally, a solid-state image pickup device is constructed by arranging a plurality of pixels, which are solid-state image pickup elements, on a silicon substrate. FIG. 12 shows an example of the configuration of the two-dimensional solid-state imaging device and the flow of electric signals. The solid-state imaging device includes a light receiving unit 102 that converts incident light into an electric signal by a photodiode or the like and a charge transfer unit 103 that transfers the electric signal, and the electric signal is transferred to the output buffer 105.

In such a solid-state image pickup device, a color filter is formed on the light receiving portion in order to obtain a color image. Complementary color solid-state imaging device,
It has a large number of pixel blocks such as 107 for receiving light of yellow (displayed as Ye), cyan (displayed as Cy), green (displayed as G), and magenta (displayed as Mg). The color filter consists of three layers, a Ye layer, a Cy layer, and a Mg layer,
A color filter is formed by stacking a Ye layer and a Cy layer on the G pixel. In many cases, a microlens that collects incident light is formed on the light receiving portion above the color filter. Next, a conventional method for manufacturing a color solid-state imaging device will be described with reference to FIGS. 13 to 19.

As shown in FIG. 13, the silicon substrate 2
A light receiving portion 203 including a photodiode and a charge transfer portion 205 are formed on 01. Then, a light-shielding film 207 such as Al or MoSi is formed on the surface of the charge transfer unit 205 so that light does not enter the charge transfer unit 205 and cause a malfunction.

Next, as shown in FIG. 14, the light receiving section 2
03 and the charge transfer portion 205, a light-transmitting planarizing film 209 containing polystyrene as a main component is formed. Further, an ultraviolet-sensitive dyeing substrate 211 containing casein or gelatin as a main component is applied on the flattening film 209. next,
As shown in FIG. 15, the dyeing substrate 21 is exposed to ultraviolet rays.
1 is selectively exposed to light and developed to form a pattern corresponding to the first color pixel, and then dyed.

Next, as shown in [FIG. 16], a light-transmitting intermediate protective film 215 is formed. Subsequently, a dyeing substrate is applied, and this is subjected to selective ultraviolet light exposure and development to form a pattern 217 corresponding to a second color pixel and dyeing.

Next, as shown in FIG. 17, a light-transmitting intermediate protective film 219 is formed. Subsequently, a dyeing substrate is applied, and this is subjected to selective ultraviolet light exposure and development to form a pattern 221 corresponding to a pixel of the third color and dyeing. Then, a planarization film 223 having a light-transmitting property is formed.

Next, as shown in FIG. 18, a heat-deformable resin layer 225 is selectively formed on the pixels. Then, by heating and melting the resin layer 225, [FIG.
9] to form a microlens 227.

Although the conventional method for manufacturing a color solid-state image pickup device has been described above, this method has a drawback that the shapes of the end portions of the color filters 213, 217 and 221 are disturbed. Hereinafter, the reason why the shape of the end of the color filter is disturbed will be described.

[FIG. 20] shows a state in which the dyed substrate 221 is exposed to ultraviolet light and is exposed. UV mask 2
It enters through the 12 openings and exposes the dyed substrate 221. However, a part of the incident light 210 passes through the dye substrate 221 and is reflected by the light shielding film 207 on the charge transfer section 205 to expose the dye substrate 221 from below. Since the shape of the light-shielding film 207 is a bowl-like shape,
The reflected light of No. 7 becomes wider than the opening width of the mask 212. Therefore, the end of the exposure region 214 has a gentle tail, and a steep end cannot be obtained. This is the reason why the edges of the color filter are disturbed.

As described above, when the end portion of the color filter is disturbed, the incident path to the photodiode becomes non-uniform,
The image is uneven. Further, if the end of the color filter is gently drawn, in the worst case, the color filter will spread to the adjacent pixel, and the colors will be mixed. In a black-and-white CCD, the lens becomes non-uniform due to the reflected light from the light-shielding film, causing unevenness in the image.

[0012]

As described above, in the conventional color filter manufacturing process of the solid-state image pickup device, there is a drawback that the end portions of the color filter pattern and the lens pattern are disturbed. The present invention eliminates the above drawbacks,
An object of the present invention is to provide a method for forming a color filter pattern and a lens pattern having sharp edges, and a method for manufacturing a solid-state imaging device without image unevenness or color mixture.

[0013]

In order to achieve the above object, the present invention comprises a step of forming an ultraviolet absorbing layer transparent to visible light on a substrate on which a plurality of light receiving portions and charge transfer portions are formed. A method of manufacturing a solid-state imaging device, comprising: a step of forming an ultraviolet photosensitive film on the ultraviolet absorbing layer; and a step of selectively exposing the ultraviolet photosensitive film to ultraviolet light.

Further, a step of forming an ultraviolet absorbing film transparent to visible light on a substrate having a plurality of light receiving parts and charge transfer parts formed thereon, and flattening transparent to the visible light on the ultraviolet absorbing film. Manufacture of a solid-state imaging device comprising: a step of forming a layer; a step of forming an ultraviolet-sensitive film on the planarizing layer; and a step of selectively exposing the ultraviolet-sensitive film to ultraviolet light. Provide a way.

Further, a step of forming a flattening layer transparent to visible light on the substrate on which a plurality of light receiving parts and charge transfer parts are formed, and ultraviolet absorption transparent to visible light on the flattening layer. Manufacture of a solid-state imaging device, comprising: a step of forming a film; a step of forming an ultraviolet-sensitive film on the ultraviolet-absorbing film; and a step of selectively exposing the ultraviolet-sensitive film to ultraviolet light. Provide a way.

[0016]

When the means provided by the present invention is used, since the ultraviolet absorbing layer is formed on the light receiving portion and the charge transfer portion, reflection from the surface of the charge transfer portion is prevented when the ultraviolet photosensitive film is selectively exposed to ultraviolet light. Instead, the edge of the photosensitive portion of the ultraviolet photosensitive film becomes sharp. Therefore, when the ultraviolet light-sensitive film is used as a dyeing substrate for the color filter, a color filter pattern having sharp edges can be formed. Further, since it is transparent to visible light, it is not necessary to pattern this ultraviolet absorbing layer, and as a result, the number of steps hardly increases.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in FIG. 1, a silicon substrate 30
A light receiving portion 303 and a charge transfer portion 305, which are photodiodes, are formed on the first layer. Then, the charge transfer unit 3 is prevented from entering the charge transfer unit 305 and causing a malfunction.
A light shielding film 307 made of Al, MoSi, or the like is formed on the surface 05.

Next, as shown in FIG. 2, the light receiving section 30
A flattening film 309 which has a light-transmitting property and absorbs i-line (ultraviolet light having a wavelength of 365 nm emitted by a mercury lamp) is formed on the charge transfer unit 305 and the charge transfer unit 305. An example of this is a material containing polystyrene as a main component and adding benzophenone. Further, an i-ray-sensitive dyeing substrate 311 containing casein or gelatin as a main component is applied on the flattening film 309.

Next, as shown in FIG. 3, the dye substrate 311 is selectively exposed to light and developed by i-line exposure to form a pattern corresponding to the first color pixel. At this time, since the flattening film 309 that absorbs the i-line is formed, the i-line is not reflected from the aluminum light-shielding film 307 on the surface of the charge transfer portion 305. Therefore, a dyed substrate 311 having sharp edges is obtained. Then, dye and color pattern 3
Get 13.

Next, as shown in FIG. 4, a light-transmitting intermediate protective film 315 is formed. Subsequently, a dye substrate is applied, selectively removed by i-line exposure and development, and dyed for the second color to obtain a color filter pattern 317.

Next, as shown in FIG. 5, an intermediate protective film 319 having a light transmitting property is formed. Subsequently, a dye substrate is applied, and the dye substrate is selectively removed by i-line exposure and development, and the third color is dyed to obtain a color filter pattern 321. Then, the planarizing film 3 having translucency
23 is formed. Then, the micro lens 327 is formed.

Although the first embodiment has been described above, when this method is used, there is no reflection of i-line from the surface of the charge transfer portion 305 during i-line exposure. Therefore, it is possible to form a color filter having a sharp edge. As a result,
It is possible to form a color solid-state imaging device without image unevenness or color mixture. Further, since it is transparent to visible light, it is not necessary to pattern this ultraviolet absorbing layer, and as a result, the number of steps hardly increases.

In the first embodiment, the intermediate protective films 315, 31
9 and the flattening film 323 are not mentioned as i-ray absorbing films, but in order to increase the absorption intensity of i-rays and to maintain the process consistency, these layers are i-ray absorbing films. It may be formed of an absorption film.

Further, three layers of color filters may be formed on the same plane without forming the intermediate protective film. In this case, a chemical treatment is required to prevent color mixing between adjacent filters. Next, a second embodiment using an ultraviolet absorbing film will be described with reference to FIGS. 6 to 8.

As shown in FIG. 6, the silicon substrate 40
A light receiving portion 403 and a charge transfer portion 405, which are photodiodes, are formed on the first substrate 1. Subsequently, the charge transfer unit 4 is prevented from entering the charge transfer unit 405 so as not to cause malfunction.
A light shielding film 407 such as Al or MoSi is formed on the surface 05. Then, an ultraviolet absorption film 408 which has a light-transmitting property and absorbs i-line is formed. Examples of this include a thin TiW film, a TiMo film, and a TiN film formed by sputtering. Alternatively, a thin carbon film or the like may be used.

Next, as shown in FIG. 7, the light receiving section 40
3 and the charge transfer portion 405, a planarization film 409 containing polystyrene as a main component is formed. Further, the flattening film 40
An i-ray-sensitive dyeing substrate 411 containing casein, gelatin or the like as a main component is applied onto the substrate 9.

Next, as shown in FIG. 8, by exposing the dye substrate 411 by i-line exposure, the regions corresponding to the yellow and green pixels are left and other regions are selectively removed. At this time, since the ultraviolet absorbing film 408 that absorbs the i-line is formed, the aluminum light-shielding film 4 on the surface of the charge transfer portion 405 is formed.
There is no i-line reflection from 07. Therefore, a dyed substrate 411 with sharp edges is obtained. Subsequently, the dyeing substrate 411 is dipped in a yellow dyeing solution and the dyeing substrate 411 is colored with a yellow color filter 41.
Change to 3. The subsequent steps are the same as those in the first embodiment. That is, cyan and magenta color filters are formed, and microlenses are formed.

Although the second embodiment has been described above, when this method is used, there is no reflection of i-line from the surface of the charge transfer portion 405 during i-line exposure. Therefore, it is possible to form a color filter having a sharp edge. As a result,
It is possible to form a color solid-state imaging device without image unevenness or color mixture. Further, since it is transparent to visible light, it is not necessary to pattern this ultraviolet absorbing layer, and as a result, the number of steps hardly increases. Next, a third embodiment using an ultraviolet absorbing film will be described with reference to FIGS. 9 to 11.

As shown in FIG. 9, a silicon substrate 50
A light receiving portion 503 and a charge transfer portion 505, which are photodiodes, are formed on the first substrate 1. Subsequently, the charge transfer unit 5 is prevented from entering the charge transfer unit 505 and causing a malfunction.
A light shielding film 507 made of aluminum is formed on the surface 05.

Next, as shown in FIG. 10, the light receiving section 5
03 and the charge transfer portion 505, a flattening film 509 containing polystyrene as a main component is formed. Then, an ultraviolet absorbing film 510 which is transparent and absorbs i-line is formed. As an example of this, a thin TiW film formed by sputtering or TiMo
There are films, TiN films and the like. Alternatively, a thin carbon film or the like may be used. Further, an i-ray-sensitive dyeing substrate 511 containing casein, gelatin or the like as a main component is applied on the flattening film 509.

Next, as shown in FIG. 11, the dye substrate 511 is exposed by i-line exposure, and the regions corresponding to the yellow and green pixels are left and other regions are selectively removed. At this time, since the ultraviolet ray absorbing film 510 for absorbing the i-line is formed, the i-line is not reflected from the aluminum light-shielding film 507 on the surface of the charge transfer portion 505. Therefore, a dyed substrate 511 with sharp edges is obtained. Subsequently, the dyeing substrate 511 is dipped in a yellow dyeing solution to make the dyeing substrate 511 a yellow color filter 5.
Change to 13. The subsequent steps are the same as those in the first embodiment. That is, cyan and magenta color filters are formed, and microlenses are formed.

Although the third embodiment has been described above, when this method is used, there is no i-line reflection from the surface of the charge transfer portion 505 when i-line exposure is performed. Therefore, it is possible to form a color filter having a sharp edge. As a result,
It is possible to form a color solid-state imaging device having no image unevenness or color mixture. Further, this i-ray absorption layer does not need to be patterned. Therefore, the number of steps hardly increases.

In the above, the first, second, and third embodiments have shown the example in which the i-line is used as the exposure light of ultraviolet rays. However, the wavelength is not limited to this, and it is sufficient if the wavelength is shorter than that of visible light. Further, exposure light having a shorter wavelength may be used.

Further, in the first, second, and third embodiments, the color filters used four colors of complementary colors yellow, cyan, green, and magenta. (Blue, green) may be used.

[0036]

As described above, according to the present invention, since the ultraviolet absorbing layer is formed on the light receiving portion and the charge transfer portion, the surface of the charge transfer portion is selectively exposed to the i-line. There is no reflection from, and the edge of the photosensitive portion of the ultraviolet photosensitive film becomes steep. Therefore, when the UV photosensitive film is used as a dyeing substrate of a color filter, a color filter having a sharp edge can be formed. Further, since this ultraviolet absorbing layer does not need to be patterned, the number of steps hardly increases. As a result, it is possible to provide a method for manufacturing a color solid-state imaging device without image unevenness or color mixture.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a first embodiment of the present invention.

FIG. 3 is a sectional view showing a first embodiment of the present invention.

FIG. 4 is a sectional view showing a first embodiment of the present invention.

FIG. 5 is a sectional view showing a first embodiment of the present invention.

FIG. 6 is a sectional view showing a second embodiment of the present invention.

FIG. 7 is a sectional view showing a second embodiment of the present invention.

FIG. 8 is a sectional view showing a second embodiment of the present invention.

FIG. 9 is a sectional view showing a third embodiment of the present invention.

FIG. 10 is a sectional view showing a third embodiment of the present invention.

FIG. 11 is a sectional view showing a third embodiment of the present invention.

FIG. 12 is a plan view showing the configuration of a conventional solid-state imaging device.

FIG. 13 is a sectional view showing a conventional example.

FIG. 14 is a sectional view showing a conventional example.

FIG. 15 is a sectional view showing a conventional example.

FIG. 16 is a sectional view showing a conventional example.

FIG. 17 is a sectional view showing a conventional example.

FIG. 18 is a sectional view showing a conventional example.

FIG. 19 is a sectional view showing a conventional example.

FIG. 20 is a sectional view showing a conventional example during exposure.

[Explanation of symbols]

102, 203, 303, 403, 503 Light receiving part 103, 205, 305, 405, 505 Charge transfer part 105 Output buffer 107 Pixel block 201, 301, 401, 501 Silicon substrate 207, 307, 407, 507 Light shielding film 209, 309 , 409, 509, 223 Flattening film 211, 311, 411, 511 Dyeing substrate 212 Mask 213, 313, 413, 513 Yellow color filter 214 Exposure area 215, 219 Intermediate protective film 217 Cyan color filter 221 Magenta color filter 225 Resin layer 227, 327, 427, 527 Microlens 408, 510 UV absorption film

Claims (3)

[Claims] 1. A step of forming an ultraviolet absorbing layer transparent to visible light on a substrate having a plurality of light receiving parts and charge transfer parts formed thereon, and a step of forming an ultraviolet photosensitive film on the ultraviolet absorbing layer. And a step of selectively exposing the ultraviolet-sensitive film to ultraviolet light, the method for manufacturing a solid-state imaging device. 2. A step of forming an ultraviolet absorbing film transparent to visible light on a substrate on which a plurality of light receiving parts and charge transfer parts are formed, and flattening transparent to visible light on the ultraviolet absorbing film. Manufacture of a solid-state imaging device comprising: a step of forming a layer; a step of forming an ultraviolet-sensitive film on the planarization layer; and a step of selectively exposing the ultraviolet-sensitive film to ultraviolet light. Method. 3. A step of forming a planarizing layer transparent to visible light on a substrate on which a plurality of light receiving parts and charge transfer parts are formed, and ultraviolet absorption transparent to the visible light on the planarizing layer. Manufacturing a solid-state imaging device, comprising: forming a film; forming an ultraviolet-sensitive film on the ultraviolet-absorbing film; and selectively exposing the ultraviolet-sensitive film to ultraviolet light. Method.