JPH08335686A - Color solid-state image pickup element and its manufacture - Google Patents

Abstract

PURPOSE: To facilitate the focal length alignment of microlenses and to prevent the generation of a color mixing between color filter layers adjacent to each other by a method, wherein the color filter layers are respectively formed directly on each microlens. CONSTITUTION: Charge-transfer regions 22 are formed in a semiconductor substrate 20 at constant intervals. Photodetectors correspond to first to third colors, arranged alternately with the regions 22. A pad 23 is formed in one part of the substrate 20, excluding the photodetectors and the regions 22. A flattened film 24 is formed on the substrate 20 excluding the pad 23. Microlenses 26 are respectively formed on the parts, which correspond to the upper parts of the phtodetectors, of the surface of the film 24. Color filter layers of the first to third colors are respectively formed directly on each microlens 26, with the exception of the edge parts of the lenses 26. Thereby, the generation of a color mixing between the color filter layers adjacent to each other can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color solid-state image pickup device, and more particularly to a color solid-state image pickup device suitable for improving sensitivity and preventing kon color and a method for manufacturing the same.

1 (A) to 1 (D) show manufacturing process diagrams of a conventional color solid-state image pickup device. First, reference is made to FIG. A photodiode 1 for generating a signal charge according to the intensity of light incident on the substrate 10 by a normal process.
1 and a plurality of signal charges from the photodiode 11 are alternately formed in the VCCD 12 in the charge transfer region, and a pad 13 is formed on a part of the substrate excluding the part where the photodiode and the VCCD are formed. A white solid-state image sensor is formed. Among the photodiodes 11, 11-1 is a photodiode corresponding to the first color, 11-2 is a photodiode corresponding to the second color, and 11-3 is a photodiode corresponding to the third color. The first flattening film 14 is formed on the entire surface of the substrate 10 on which the solid-state image sensor is formed. Next, the color filter layer 15 is formed on the first flattening film 14. That is, a resin layer is formed on the first planarization film 14, the resin layer is dyed and fixed to the first color, and the colored resin layer is photoetched to form the first color filter layer 15-1. Form. The above steps are repeated to form the second and third color filter layers 15-2 and 15-3 on the first planarization film 14, respectively. As a result, the color filter layers of three colors are sequentially formed on the first flattening film 14, and the process of forming the color filter layer 15 is completed. After the formation process of the color filter layer 15 is completed, the second flattening film 16 is formed on the first flattening film 14 including the color filter layer 15, and the substrate is flattened again.

Next, reference will be made to FIG. A photoresist film is coated with the microlens material 17 on the second planarization film 16, and the microlens material 17 is provided only on the upper part of each photodiode region 11 by a photoetching process.
The microlens material 17 is patterned so that the micro-lenses remain.

Referring to FIG. Second flattening film 1
The patterned microlens material 17 on 6 is heat-flowed to form a convex lens-shaped microlens 18 on the upper side of each photodiode 11.

Finally, please refer to FIG. A photoresist film 19 is applied on the second planarization film 16 on which the microlens 18 is formed, and the photoresist film 19 on the pad 13 is removed by a photoetching process to remove the second film.
The flattening film 16 is exposed. The exposed second flattening film 16 and the first flattening film 14 thereunder are sequentially etched using the photoresist film 19 as a mask to form the pad 1
Expose 3 After finally exposing the pad 13,
By removing the remaining photoresist film 19, a conventional color solid-state image pickup device is manufactured.

By applying the color solid-state image pickup device manufactured by the above method to a camera, the light incident through the camera lens is focused by the microlens 18, and the light focused by the microlens 18 is colored by the color filter layer 15.
Pass through. That is, the first color filter layer 15-1 of the color filter layer 15 selectively transmits only the light of the first color of the light focused by the microlenses, and the first color filter layer 15-1 of the plurality of photodiodes 11 is transmitted. Light of the first color is made incident on the photodiode 11-1 corresponding to the first color, and the second color filter layer 15-2 selectively transmits only the light of the second color. The light of the second color is made incident on the photodiode 11-2 corresponding to the above color, and the third color filter layer 15-3 selectively transmits only the light of the third color to correspond to the third color. Photodiode 11-
The light of the third color is made incident on 3.

Therefore, the light incident on each photodiode 11 is photoelectrically converted, and each photodiode generates a signal charge. The charges generated from the photodiode 11 are transferred to the VCCD 1 by the signal transfer operation of a normal solid-state image sensor.
After being transferred to H.C.D. 2, it is transferred to HCCD (not shown). Next, the signal charge transferred to the HCCD is transferred to the floating diffusion at the end of the device.
After being detected by n), it is amplified through an amplifier (not shown) and transferred to a peripheral circuit.

[0008]

However, the conventional method for manufacturing a color solid-state image pickup device has the following problems. 1. The photoetching process is performed three times to form the color filter layer. At this time, if the photoresist film remains in an undesired portion in the photoetching process for forming the color filter layer, a phenomenon of kelp color occurs. As a result, there is a problem that light is transmitted between the adjacent color filter layers to cause a phenomenon of kelp color.

2. Since the second flattening film exists between the microlens and the color filter layer, light is easily scattered, and the focal length to the photodiode is increased due to an error in the distance between the microlens and the color filter layer. There was a problem that it was difficult to match.

3. Second after forming the color filter layer
Since the flattening film must be formed, the process is complicated as a whole, the manufacturing time becomes long, and the device becomes thick.

The present invention is intended to solve the above problems of the prior art, and not only can the focal length be easily adjusted, but the color solid-state image pickup device and the solid color image pickup device which can prevent the dark blue color between the adjacent color filter layers. It is an object to provide a manufacturing method thereof. Another object of the present invention is to provide a color solid-state image pickup device capable of reducing the thickness of the entire device and slimming the device, and a method for manufacturing the same. Another object of the present invention is to form a color filter layer on the microlens so that the edge portion of the microlens is exposed and to transmit white light to the periphery (edge portion) of the microlens, thereby performing color solid-state imaging. It is an object of the present invention to provide a color solid-state imaging device capable of improving the sensitivity of the device and a manufacturing method thereof.

[0012]

In order to achieve the above-mentioned object, a color solid-state image pickup device of the present invention comprises a semiconductor substrate, a plurality of charge transfer regions formed on the semiconductor substrate at regular intervals. A plurality of photodetectors corresponding to the first to third colors formed to be arranged alternately with the charge transfer regions, and formed on a part of the semiconductor substrate excluding the photodetectors and the charge transfer regions. Pad, the flattening film formed on the substrate excluding the pad, the plurality of microlenses formed on the flattening film above each photodetector, and the first to third colors. Corresponding to the photodetector, the color filter layers of the first to third colors directly formed on the respective microlenses except the respective edge portions.

The method of the present invention comprises the steps of alternately forming a plurality of photodetectors corresponding to the first to third colors and charge transfer regions on the substrate, and forming the photodetectors and charge transfer regions. The step of forming a pad on a part of the substrate excluding the part, the step of forming a planarizing film on the substrate excluding the upper part of the pad, the microlens substance is applied on the planarizing film, and the photodetector Performing a patterning process so that the microlens material remains only on the upper side, a step of heat-flowing the microlens material to form the microlens on the planarization film on the upper side of the photodetector, and a hard baking step. Forming the first to third color filter layers directly on the microlenses corresponding to the first to third color photodetectors.

[0014]

EXAMPLE A color solid-state image pickup device according to an example of the present invention will be described below. FIG. 2 shows a sectional structure of a color solid-state image sensor according to an embodiment of the present invention. A color solid-state image sensor according to an embodiment of the present invention includes a semiconductor substrate 20 and a substrate 2.
0, a plurality of charge transfer VCCDs 22 formed at regular intervals, and first to third electrodes formed between the VCCDs 22 so as to be arranged alternately with the VCCDs 22.
Photodetection photodiodes 21 corresponding to the colors of
And a pad 23 formed on a part of the semiconductor substrate 20 excluding the photodiode 21 and the VCCD 22, and a planarization film 2 formed on the substrate 20 excluding the pad 23 part.
4, a plurality of microlenses 26 formed on the planarization film 24 above each photodiode 21, and first to third colors formed on the respective microlenses 26 excluding their edge portions. A plurality of color filter layers 28 corresponding to

In the color solid-state image pickup device of the present invention having the above-described structure, the color filter layers 28 corresponding to the first to third colors are formed on the respective microlenses 26 so as to be in direct contact with the microlenses. The edge portion was exposed so that the white light C was transmitted.

Each color filter layer has a rounded edge portion, and among the plurality of color filter layers 28, the first color filter layer 28-1 is the first.
Of the second color photodiode 21-1 is formed on the microlens 26, and the second color filter layer 28-2 is formed on the microlens 26 of the second color photodiode 21-2. The color filter layer 28-3 of the third color is formed on the microlens 26 corresponding to the photodiode 21-3 of the third color.

3 and 4 are manufacturing process diagrams of a color solid-state image pickup device according to an embodiment of the present invention. In one embodiment of FIG. 3, a method of manufacturing a color solid-state image sensor in which a heat flow step and a hard baking step are separately performed to form a color filter layer on a microlens is presented.

Referring to FIG. First, the photodiode 21 and the VCCD are formed on the substrate 20 by the usual method.
A plurality of 22 are alternately formed, and a pad 23 is formed on a part of the substrate 21 excluding the part where these photodiodes and VCCD are formed to manufacture a black and white solid-state image sensor. In FIG. 3A, among the plurality of photodiodes 21, the photodiode corresponding to the first color is 21-1,
The photodiode corresponding to the second color is 21-2, the third
The photodiodes corresponding to the color of are shown as 21-3, respectively. Next, a planarization film 24 is formed on the entire surface of the substrate on which the photodiode 21, the VCCD 22 and the pad 23 are formed.

Referring to FIG. The planarization film 24 on the pad 23 is removed by a photo-etching process to expose the upper surface of the pad 23.

Referring to FIG. The microlens material 2 is formed on the planarization film 24 including the upper surface of the pad 23.
5 is applied, and the microlens material 25 is patterned by a photoetching process so that the microlens material remains only on the planarization film 24 corresponding to the photodiode 21.

Next, the patterned microlens material 25 is caused to flow by heat to form microlenses 26 on the flattening film 24 at positions corresponding to the photodiodes, as shown in FIG. 3D. After forming the microlens 26, as shown in FIG. 3 (E), the first dyeing layer 27 is applied over the entire surface of the substrate, and then the first dyeing layer is dyed and fixed to the first color by a normal dyeing process. Let

Next, as shown in FIG. 3 (F), after the dyeing process is performed, the colored first dyeing layer 27 is patterned, which corresponds to the first color of the plurality of photodiodes 21. The first dyeing layer is left only on the microlens 26 located above the photodiode 21-1 and the remaining first
Remove all the dyed layers. At this time, as shown in FIG. 3F, the first dyeing layer 27 remaining on the photodiode 21-2 corresponding to the first color is the microlens 26.
Is not formed so as to cover the entire surface of the microlens 26, but is formed so that the edge portion of the microlens 26 is exposed.

In FIG. 4 (E), since the first dyeing layer 27 is applied by the spin coating method, the first dyeing layer 27 is applied thicker in the peripheral portion of the microlens than in the central portion of the microlens 26. It Therefore, the first dyed layer 2
By patterning 7, the first dyeing layer 27 is formed thicker in the edge portion A than in the central portion B, as shown in FIG.

After patterning the first dyed layer 27,
When the hard baking is performed, the first color filter layer 28 is formed as shown in FIG.
-1 is formed. The reason why the first dyeing layer is formed so that the edge portions of the microlenses 26 are exposed at a constant interval is to transmit white light.
When hard baking is performed, both thick edge portions of the first dyeing layer 27 flow further than the central portion, the first color filter layer is formed in a round shape, and the edge portions of the microlenses 26 are exposed by a constant distance d. Formed as described above.

After the first color filter layer 28-1 is formed, the second step is performed over the entire surface of the substrate by the same step as the step of forming the first color filter layer 28-1.
Of the plurality of photodiodes 21 and the second dyeing layer is dyed and fixed to the second color.
The second dyeing layer is patterned so that the second dyeing layer remains only on the upper side of the photodiode 21-2 corresponding to the color of FIG.
The second color filter layer 28-2 is formed as shown in (H). Next, when the third color filter layer 28-3 is formed by the above method, the third color filter layer 28-3 is formed on the microlens 26 and the color filter layer 28 is formed. As a result, the color solid-state image sensor according to the embodiment of the present invention is obtained.

Since the color solid-state image pickup device has the color filter layer 28 formed directly on the microlens 26, it has an effect of preventing kon color, and the white light C is transmitted through the edge portion of the microlens 26. Since the color filter layer is not formed on the edge portion of the microlens 26, there is an effect of improving the sensitivity of the color solid-state image pickup device.

5 and 6 are manufacturing process diagrams of a color solid-state image pickup device according to another embodiment of the present invention. In the examples of FIGS. 5 and 6, a method of manufacturing a color solid-state image pickup device in which a heat flow step and a hard baking step are simultaneously performed to form a color filter layer on a microlens is presented.

Referring to FIG. 5A, the photodiode 31 and the VCCD 3 are formed on the substrate 30 as in the previous embodiment.
2 and 2 are alternately formed, and the pad 3 is formed on a part of the substrate 31.
3 is formed, and then the planarizing film 34 is formed on the entire surface of the substrate.
To form. The plurality of photodiodes 31 includes a photodiode 31-1 corresponding to the first color, a photodiode 31-2 corresponding to the second color, and a photodiode 31-3 corresponding to the third color. .

As shown in FIG. 5B, the flattening film 34 on the pad 33 is removed by a photo-etching process to expose the upper surface of the pad 33. As shown in FIG. 5C, the microlens material 35 is deposited on the planarization film 34 including the upper surface of the pad 33, and the planarization film 34 on each photodiode 31 is formed by a photoetching process.
The microlens material 35 is patterned so that the microlens material remains only on the top.

As shown in FIG. 5D, the first dyeing layer 36 is applied on the substrate 30 containing the microlens material 35. The first dyeing layer 36 is dyed and fixed to the first color by a normal dyeing process.

After performing the dyeing process, the first dyeing layer 36 colored by the photo-etching process is patterned as shown in FIG.
Of the photodiodes 31-1 corresponding to the first color
The first dyed layer 36-1 is left only on the upper side of.

By repeating the steps of FIGS. 5D and 6E, among the plurality of photodiodes 31, the photodiodes 31-2 and 3 corresponding to the second color and the third color, respectively.
When the second and third dyed layers 36-2 and 36-3 are respectively formed on the flattening film 34 on the upper side of 1-3, the result is as shown in FIG. 6 (F). That is, the second dyeing layer is applied over the entire surface of the substrate, and the applied second dyeing layer is dyed and fixed,
The second dyed layer 36-2 is patterned so that the second dyed layer remains only above the photodiode 31-2 corresponding to the second color. Then, a third dye layer is applied over the entire surface of the substrate, the applied third dye layer is dyed and fixed to a third color, and the colored third dye layer is patterned to form a third color. The third dyed layer 36-3 is formed only on the upper side of the photodiode 31-3 corresponding to. After forming the dyeing layer, the microlens material 35 and the first to third dyeing layers 36-1 to 36-3 formed thereon are simultaneously subjected to heat flow, and then simultaneously hard baked. Therefore, the microlens material 35 flows, microlenses 37 corresponding to the respective photodiodes 31 are formed, and the first to third color filter layers 38-1 to 38-3 are formed on the microlens 37. I will let you. As a result, the color solid-state image pickup device according to this embodiment in which the color filter 38 is formed on the microlens 37 is obtained.

Referring to FIG. 6G, similarly to this embodiment, the edge portion of the microlens 37 has a constant distance d.
The color filter layers 38-1 to 38-3 are directly formed on the microlens 37 so as to be exposed only.

Even when the microlens material 35 and the dyeing layer 36 are simultaneously heat-flowed, each color filter layer is formed so that the edge portion of the microlens 37 is exposed as in the previous embodiment. This is each dyed layer 36
This is because the degree of heat flow is smaller than that of the microlens material 35.

In the above two examples, the dyeing layer was applied to form the color filter layer, and the applied dyeing layer was dyed and fixed to the corresponding color. When the included pigment layer is used, since the pigment layer itself contains color, it is possible to form the color filter layer by performing only the photoetching step without performing the dyeing and fixing step.

[0036]

As described above, according to the present invention, the following effects can be obtained. 1. By forming a microlens and then forming a color filter layer on the microlens, it is possible to prevent dark color between adjacent color filter layers. Then, by forming a color filter layer on the microlens so that the edge portion of the microlens is exposed and transmitting white light through the exposed microlens, the sensitivity of the solid-state imaging device is improved. You can

2. By exposing the pad at the beginning of the process, the etching process for exposing the pad at the end of the process and the remaining photoresist removal process, etc. are eliminated, and particle generation due to it is prevented, and the device due to particle generation is removed. Damage can be prevented. Further, since the pad is exposed in one photo-etching process using only one planarization film, the complicated process for exposing the conventional pad can be eliminated and the process can be simplified. .

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a conventional color solid-state imaging device.

FIG. 2 is a manufacturing process diagram of a color solid-state imaging device of the present invention.

FIG. 3 is a manufacturing process diagram of a color solid-state imaging device according to an embodiment of the present invention.

FIG. 4 is a manufacturing process diagram of a color solid-state imaging device according to an embodiment of the present invention.

FIG. 5 is a manufacturing process diagram of a color solid-state imaging device according to another embodiment of the present invention.

FIG. 6 is a manufacturing process diagram of a color solid-state imaging device according to another embodiment of the present invention.

[Explanation of symbols]

20, 30 ... Semiconductor substrate, 21, 31 ... Photodiode, 22, 32 ... Charge transfer area (VCCD), 23, 3
3 ... Pad, 24, 34 ... Flattening film, 25, 35 ... Microlens material, 26, 37 ... Microlens, 2
7, 36 ... Color filter dye layer, 28, 38 ... Color filter layer.

Front Page Continuation (72) Inventor Jin Sop Shim Republic of Korea Chung Chong Buk-do Chung-si Ga Kyung-dong 1190 Seong Department 101-303 (72) Inventor Gan Bok Sung South Korea・ Seoul-Shi Dongdaemungu Limung 2-Don 264-227

Claims (4)

[Claims] 1. A semiconductor substrate, a plurality of charge transfer regions formed at regular intervals on the semiconductor substrate, and a semiconductor between the charge transfer regions so as to be alternately arranged with the charge transfer regions. A plurality of photodetectors corresponding to the first to third colors formed on the substrate; a pad formed on a part of the semiconductor substrate excluding the photodetectors and the charge transfer region; Corresponding to the flattening film formed on the substrate, the plurality of microlenses formed on the flattening film above each photodetector, and the photodetectors of the first to third colors, A color solid-state imaging device, comprising: a color filter layer of first to third colors directly formed on each microlens except for respective edge portions. 2. A step of alternately forming a plurality of photodetectors corresponding to the first to third colors and charge transfer regions on a substrate, and a portion in which the photodetectors and charge transfer regions are formed. The step of forming a pad on a part of the removed substrate, the step of forming a flattening film on the substrate excluding the upper part of the pad, and the microlens substance applied on the flattening film, Patterning so that only the microlens material remains, a step of heat-flowing the microlens material to form the microlens on the planarization film above the photodetector, and a hard baking step. To the step of directly forming the first to third color filter layers on the microlenses corresponding to the photodetectors of the third to third colors, the method for manufacturing a color solid-state imaging device. 3. The color solid-state image pickup device according to claim 2, wherein each of the color filter layers is formed only on the microlens except for the edge portion in order to transmit white light to the edge portion. Method. 4. A step of alternately forming a plurality of photodetectors corresponding to the first to third colors and charge transfer regions on a semiconductor substrate, and the photodetectors and the charge transfer regions being formed. The step of forming a pad on a part of the substrate except the part where the pad is removed, the step of forming a flattening film on the substrate from which the pad is removed, the heat flow step and the hard baking step are performed at the same time,
And a step of forming a microlens and color filter layers of first to third colors on the flattening film.