JP2677786B2 - Method for manufacturing solid-state imaging device - Google Patents

Description

The present invention relates to a method for manufacturing a solid-state imaging device suitable for use in, for example, a color video camera. SUMMARY OF THE INVENTION The present invention is a method for manufacturing a solid-state image pickup device suitable for use in, for example, a color video camera, which comprises forming a transparent flattening film on a solid-state image pickup device, and then forming oxygen on the transparent flattening film. By performing a plasma treatment, then forming a layer to be dyed on the transparent flattening film subjected to the oxygen plasma treatment, after that, by dyeing the layer to be dyed in a predetermined color to form a color filter, It is possible to obtain a solid-state image pickup device which is free from unevenness in drying and which is free from peeling and swelling of color filters. [Prior Art] Conventionally, as a solid-state imaging device used in a color video camera, a device as shown in FIG. 2F has been proposed. In FIG. 2F, (1) shows a solid-state image sensor, and this solid-state image sensor (1) has a step on its surface between the light receiving portion (2) and the portion (3) other than the light receiving portion. ing. Therefore, in the solid-state imaging device of the present example, the transparent flattening film (4) is formed on the surface of the solid-state image pickup device (1), and the solid-state image pickup device (1) is formed through the transparent flattening film (4). Primary color filters, that is, red, blue and green filters (5R) (5B) and (5G) are provided on the top. Incidentally, (6) and (7) are bonding pads, respectively. Conventionally, when manufacturing such a solid-state imaging device, first, as shown in FIG. 2A, after forming a transparent flattening film (4) on the surface of the solid-state image pickup device (1), the transparent flattening film ( 4) The layer to be dyed (8) is formed on it. In this case, as the transparent flattening film (4), a photo-processable resin such as an acrylic resin or a thermosetting resin such as a polyimide resin can be used, and gelatin can be used as the material of the layer to be dyed (8). A mixture of mulberry or casein and the photopolymerizing agent ammonium dichromate can be used. Here, a photo-processable resin such as an acrylic resin or a thermosetting resin such as a polyimide resin has hydrophobicity, and a mixture of gelatin, glue or casein and ammonium dichromate has hydrophilicity. Next, as shown in FIG. 2B, a mask (not shown) is aligned so as to leave only the layer to be dyed (8R) to be dyed in red, exposure is performed, and development is performed using warm water. To In this case, the transparent flattening film (4) is made of a hydrophobic material,
Further, since the layer to be dyed (8) is formed of a hydrophilic material, hot water does not remain on the transparent flattening film (4) after development due to water repellency, and hot water (only on the layer to be dyed (8R) ( 9) will remain. Then, next, as shown in FIG. 2C, warm water (9) is dried and then immersed in a red dyeing solution to form a red filter (5R) as shown in FIG. 2D. Also in this case, the red dye solution (1
0) remains. Then, as shown in FIG. 2E, after the red dyeing solution (10) is dried, a blue filter (5B) and a green filter (5G) are sequentially formed in the same manner as shown in FIG. 2F. Such a solid-state imaging device can be obtained. [Problems to be Solved by the Invention] However, in such a conventional method for manufacturing a solid-state imaging device, the dyed layer (8) is formed of a hydrophilic material as described above, and the transparent flattening film is formed. Since (4) is formed of a material having hydrophobicity, when patterning is performed so as to leave a portion (8R) to be dyed red in the layer (8) to be dyed, as shown in FIG. Hot water (9) remains only on the layer (8R) to be dyed, and the transparent flattening film (4)
There is no warm water left on top. Also, when the layer to be dyed (8R) that should be dyed red is dyed red and the red filter (5R) is formed, the red dye solution (only on the red filter (5R) as shown in FIG. 2D ( 10) remains, and the red dyeing solution (10) does not remain on the transparent flattening film (4). This also occurs when the layer to be dyed (not shown) for dyeing blue is formed after forming the red filter (5R) and when the blue filter (5B) is formed. Therefore, in such a conventional method for manufacturing a solid-state image pickup device, a drying step after patterning a portion (8R) of the layer to be dyed (8R) to be dyed red and a step after forming a red filter (5R) are performed. In the drying process, the drying process after patterning the layer to be dyed for blue and the drying process after forming the blue filter (5B), it is difficult to uniformly and uniformly dry the solid-state image sensor (1). However, there is a problem in that uneven drying may occur and a good solid-state imaging device may not be obtained. Further, in the conventional method for manufacturing a solid-state imaging device, since the dyed layer (8) having hydrophilicity is formed on the transparent transparent flattening film (4), the transparent flattening film is formed. The adhesive strength between (4) and the dyed layer (8) is extremely weak, and the color filters (5R) (5B) (5G) formed by color-coding the dyed layer (8) are transparent flattening films (4 ), There is a problem that it may be peeled off or turned over. In this case, in order to prevent such peeling and curling, it is possible to mix various coupling agents into the layered material to be dyed. There is a disadvantage that the polymerization reaction gradually progresses, the viscosity increases, and the control thereof becomes difficult. Therefore, when forming the layer to be dyed (8) on the transparent flattening film (4), a coupling agent may be spin-coated on the transparent flattening film (4) as a dilute solution. In this case, There was an inconvenience that the number of steps was increased. The present invention has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a solid-state imaging device that does not have unevenness in drying and that does not peel off or curl up of a color filter even if a coupling agent is not used. [Means for Solving Problems] In order to solve the above problems, the method for manufacturing a solid-state imaging device of the present invention includes the following steps. That is, the first step of forming a transparent flattening film on a solid-state image sensor, and exposing the transparent flattening film to an oxygen plasma atmosphere with a pressure of 0.3 to 0.7 Torr and a high frequency power of 50 to 200 watts for about 10 to 60 seconds. The second step of subjecting the layer to be dyed to hydrophilicity by the second step, the third step of directly forming the layer to be dyed on the transparent flattening film subjected to the hydrophilicity treatment, and after patterning the layer to be dyed. And a fourth step of drying the entire surface of the element, and a fifth step of dyeing the layer to be dyed with a predetermined color. Then, the color filters are formed by repeating the third to fifth steps a predetermined number of times. [Operation] According to the present invention, since the transparent flattening film is a hydrophilic transparent flattening film, water repellency on the transparent flattening film is prevented, and uniform drying can be performed. The adhesive strength with the layer to be dyed becomes large. In particular, the film thickness of the transparent flattening film is reduced by performing the hydrophilic treatment under the condition that the oxygen partial pressure is 0.3 to 0.7 Torr and the high frequency power is exposed to an oxygen plasma atmosphere of 50 to 200 watts for 10 to 60 seconds. Only the surface can be processed satisfactorily. [Embodiment] An embodiment of the method for manufacturing the solid-state imaging device of the present invention will be described below with reference to FIG. In this case, in FIG. 1, parts corresponding to those in FIG. In this example, first, as shown in FIG. 1A, a solid-state image sensor (1) including, for example, a charge coupled device (CCD) having a step between a light receiving portion (2) and a portion (3) other than the light receiving portion is provided. prepare. In FIG. 1A, (6) and (7) are bonding pads, respectively. Next, as shown in FIG. 1B, the bonding pad (6)
A transparent flattening film (4) is formed on the entire surface of the solid-state imaging device (1) so as to include (7) by spin-coating a photo-processable resin, for example, an acrylic resin, so that the surface becomes uniform. Next, as shown in FIG. 1C, a mask (12) is placed on the transparent flattening film (4), exposure and development are performed, and as shown in FIG. 1D, on the bonding pads (6) and (7). The transparent flattening film (4) is removed. Next, as shown in FIG. 1E, the solid-state imaging device (1) having the transparent flattening film (4) formed on the entire surface except the bonding pads (6) and (7) is exposed to an oxygen plasma atmosphere. . In this case, the pressure in the oxygen plasma atmosphere is set to 0.3 to 0.7 tritur (Torr), high frequency power of about 50 W to 200 W is supplied, and under such conditions, for 10 seconds to
Let it be exposed for about 60 seconds. By doing so, the transparent flattening film (4) which has been hydrophobic until then becomes the same as when a polar group is newly provided, and it becomes a transparent flattening film (11) having hydrophilicity. It is not preferable to expose the transparent flattening film (11) to a large film thickness if it is exposed to the oxygen plasma atmosphere for too long under the above conditions. Next, as shown in FIG. 1F, a dyed layer (8) made of casein and ammonium dichromate is formed on the entire surface of the transparent transparent flattening film (11), and then shown in FIG. 1G. Similarly, align a mask (not shown) so that the layer to be dyed (8R) that should be dyed with red as the first color is left
Patterning is performed as if developing. In this case, since the transparent flattening film (11) is hydrophilic, warm water as a developing solution does not exist on the dyed layer (8R) to be dyed red as shown in FIG. 1G, It also remains on the transparent flattening film (11). Therefore, after drying the entire surface as shown in FIG. 1H,
As shown in FIG. 1I, the layer to be dyed (8R), which is to be dyed in red, is dyed in red by immersing it in a red dyeing solution to form a red filter (5R). Also in this case, the red dyeing solution (10) contains the red filter (5R) and the transparent flattening film (4).
It will remain on top. Therefore, as shown in FIG. 1J, the entire surface is then dried, and then the layer to be dyed is applied again to the entire surface, followed by patterning so as to leave a portion to be dyed blue, and then using a blue dyeing solution. As shown in Fig. 1K, a blue filter (5B) is formed. Next, the layer to be dyed is applied again to the entire surface, and then patterning is performed so as to leave a portion to be dyed green, and then a green dyeing solution is used, as shown in FIG. 1L, a red filter (5R) and a blue filter. Next to (5B), a green filter (5G) is formed. According to this embodiment, as shown in FIG. 1E, the transparent flattening film (4) having hydrophobicity is subjected to oxygen plasma treatment to form the transparent flattening film (11) having hydrophilicity. Therefore, when exposed and developed using a mask and patterned so as to leave the dyed layer (8R) that should be dyed in red, the warm water as the developing solution has the hydrophilic dyed layer (8R). And remain on both sides of the hydrophilic transparent flattening film (11). Further, even when the red filter (5R) is formed, the red dyeing solution (10) remains on both sides of the hydrophilic red filter (5R) and the hydrophilic transparent flattening film (11). . When a layer to be dyed to dye blue is formed, warm water is used for the red filter (5R) that has already been formed, the layer to be dyed to dye blue, and the exposed transparent flattening film. (11) Remains on and then blue filter (5
B), the red filter (5
R), the blue filter (5B) and the exposed transparent flattening film (11) leave a blue dyeing solution. Therefore, according to the present embodiment, the drying step after forming the dyed layer (8R) to be dyed red, the drying step after forming the red filter (5R), the dyed layer to be dyed blue Since the entire surface can be dried evenly in the drying step after forming the film and the drying step after forming the blue filter (5B), there is an advantage that a solid-state imaging device having no drying unevenness can be obtained. Further, according to the present embodiment, as described above, the transparent flattening film (4) having hydrophobicity is subjected to oxygen plasma treatment to form the transparent flattening film (11) having hydrophilicity, which has the hydrophilicity. Since the hydrophilic dyeing layer (8) is formed on the transparent flattening film (11), the adhesive strength between the transparent flattening film (11) and the dyeing layer (8) becomes large. , Even when the color filters (5R) (5B) (5G) are formed after that, a solid-state imaging device in which these color filters (5R) (5B) (5G) do not peel off or turn up is obtained. There is a benefit of being able to In the above examples, the case where a mixture of gelatin and ammonium dichromate was used as the material of the layer to be dyed was described, but instead of this, glue, polyvinyl alcohol or casein and ammonium dichromate were used. It is needless to say that a mixture of the above can be used, and in this case, the same effect as the above can be obtained. Further, in the above-mentioned embodiment, the case where the photo-processable resin is used as the transparent flattening film (4) has been described, but instead of this, a thermosetting resin, for example, a polyimide resin can be used. However, it goes without saying that the thermosetting resin having hydrophobicity can be made hydrophilic by oxygen plasma treatment, and the same effect as described above can be obtained. Further, in the above-mentioned embodiment, the case where the transparent flattening film (4) on the bonding pads (6) and (7) is subsequently removed after forming the transparent flattening film (4) has been described. The transparent flattening film (4) on the bonding pads (6) and (7) may be removed after the color filters (5R) (5B) (5G) are formed. Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention. According to the present invention, the transparent flattening film (4) is made of a hydrophilic transparent flattening film (11), and water repellency on the transparent flattening film (11) is prevented to make it uniform. A solid-state image pickup device having no drying unevenness and no peeling of the color filter or curling is obtained since the adhesive strength with the layer to be dyed (8) is increased while being able to dry. There is a benefit of being able to. Further, in the method for manufacturing a solid-state imaging device according to the present invention, the hydrophilic treatment of the transparent flattening film is performed in an oxygen plasma atmosphere with an oxygen partial pressure of 0.3 to 0.7 Torr and a high frequency power of 50 to 200 W (watt).
Since exposure is performed for 10 to 60 seconds, oxygen plasma etching unlike the conventional treatment does not occur and film slippage does not increase, and good surface treatment can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a manufacturing process drawing of a solid-state imaging device showing an embodiment of a manufacturing method of a solid-state imaging device of the present invention, and FIG. 2 is a process drawing showing a manufacturing method of a conventional solid-state imaging device. is there. (1) is a solid-state image sensor, (4) is a transparent transparent flattening film, (5R) is a red filter, (5B) is a blue filter, (5G) is a green filter, and (8) is a dyed layer, (9)
Is hot water, (10) is a red dyeing solution, and (11) is a hydrophilic transparent flattening film.

Continuation of front page    (72) Inventor Toshiro Kurusu               982 Daimaru, Noguchi, Kokubun-shi Sony Kokubun Semi               Conductor Co., Ltd. (72) Inventor Morio Imayoshi               982 Daimaru, Noguchi, Kokubun-shi Sony Kokubun Semi               Conductor Co., Ltd. (72) Inventor Yoshihisa Matsumura               982 Daimaru, Noguchi, Kokubun-shi Sony Kokubun Semi               Conductor Co., Ltd.                (56) References JP-A-59-192208 (JP, A)                 JP-A-61-73103 (JP, A)                 JP-A-61-43701 (JP, A)                 Actual development Sho 56-132876 (JP, U)

Claims (1)

(57) [Claims] The first step of forming a transparent flattening film on the solid-state image sensor, the transparent flattening film having a pressure of 0.3 to 0.7 Torr and a high frequency power of 50 to 20.
A second step of performing a hydrophilizing treatment by exposing it to a 0 watt oxygen plasma atmosphere for about 10 to 60 seconds, and forming a layer to be dyed directly on the hydrophilizing transparent flattening film. A third step, a fourth step of drying the entire surface of the element after patterning the layer to be dyed, and a fifth step of dyeing the layer to be dyed with a predetermined color; A method for manufacturing a solid-state imaging device, wherein the color filter is formed by repeating the fifth step through a predetermined number of times.