JPS6251504B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a color solid-state image sensor in which a color filter is integrally formed on the light-receiving surface of the solid-state image sensor.

Currently, in solid-state image sensors using charge transfer devices such as CCD type or MOS type, attempts are being made to manufacture color solid-state image sensors by integrally forming color filters on the light-receiving surface of the image sensor. .

However, when a color filter is integrally formed on the light-receiving surface of an image sensor, there are the following drawbacks. For example, a layer to be dyed, such as a gelatin layer, is formed to have a uniform thickness over the entire surface of the device, excluding the electrode lead terminals and the cut portion, on a device on which an image sensor is formed, and this gelatin layer is selectively coated with a photoresist layer. In the past, a color filter was formed directly on the image sensor by dyeing it separately using a mask, but in this case, color mixing (bleeding) occurred due to misalignment of the dyeing mask using photoresist, which deteriorated the color filter characteristics, and the light receiving Due to the difference in level between the concave part and the surrounding area, when a uniform layer to be dyed is deposited on the entire surface, breakage or cracks may occur in the step part, which may cause local swelling or peeling of the layer to be dyed. There were drawbacks such as the occurrence of cracks.

On the other hand, there is also a method of manufacturing a color solid-state image sensor that is completely different from the method described above. The manufacturing method of this color solid-state image sensor will be explained based on FIGS. Directly dye the layer 5 so that the concave part of the light receiving part (hereinafter referred to as photodiode) 1 is filled in the surface of 4.
(Fig. 1A), then harden only the dyed layer 5 on the photodiode 1 on which the first color filter component is to be formed, remove the other dyed layer 5, and remove the remaining dyed layer 5. The dyed layer is dyed to form a first color, for example, a green filter component 6G (FIG. 1B).
Note that 3 is a shielding film formed to prevent light from being irradiated onto the transfer section. Next, after depositing a transparent isolation layer 7 on the entire surface of the light-receiving surface containing the green filter component 6G (FIG. 1C), only the photodiode 1' corresponding to the second color is dyed in the same manner as described above. A layer is formed and dyed to form a filter component 6R of a second color, e.g. red (FIG. 1D), and then the same process is repeated to form a third color, e.g. blue, via the isolation layer 7'. A filter component 6B is formed (FIG. 1E). In this way, a color filter 6 having so-called filter components of each color is formed on the surface of the element 4 to constitute a color solid-state image sensor.

According to this color solid-state image sensor, each filter component is not a continuous film but is isolated from each other by isolation layers 7 and 7', so that there is no color mixing (bleeding) as a color filter, and there is no local swelling or swelling. Peeling and the like are also avoided.

However, even with this color solid-state image sensor,
For example, when the layer 5 to be dyed shown in FIG. 1A is applied, the layer 5 to be dyed at the stepped portion 8 is formed thin due to the step difference due to the unevenness of the element surface, resulting in cracks in the step, and heat treatment etc. in the subsequent steps are required. Over time, the lid component may peel off and fall off. Furthermore, since the layer 5 to be dyed is directly adhered to the surface of the device, there is a possibility that it will have an adverse effect on the device.

The present invention provides a method for manufacturing a color solid-state image sensor that eliminates the above-mentioned conventional drawbacks and improves photosensitivity.

A method of manufacturing a color solid-state image sensor according to an embodiment of the present invention will be described in detail below using FIGS. 2A to 2I.

In this embodiment, a case is shown in which a color filter consisting of three colors of green, red, and blue is formed on the light receiving surface of a solid-state image sensor.

First, as shown in FIG. 2A, an interline solid-state image pickup device 4 made of, for example, a CCD charge transfer device is formed. The figure shows a particularly enlarged view of the light-receiving surface of the image sensor, which has a plurality of photodiodes 1 that serve as picture elements and a transfer electrode 2 formed adjacent to the photodiodes 1, and is connected to a two-phase or three-phase clock voltage. Therefore, a transfer section 2' that transfers charges in one direction and a shielding film 3 that blocks light from entering the transfer section are provided. A photocurable resin 10 is applied to the entire light-receiving surface of the solid-state image sensor 4 (FIG. 2B). Thereafter, in order to cure only the concave portions of the light-receiving surface, a resin film pattern 10' is formed by exposure and development using a photomask 21 having a predetermined pattern (FIGS. 2C and 2D). Furthermore, the characteristics of this resin 10' are that it has chemical resistance and good adhesion to the device.
A material with high light transmittance in the wavelength range of m is preferable.

Here, regarding steps A to D in FIG.
This will be explained in more detail using Figures A to C. In FIGS. 2 B to E, when using a material that has the property of flowing after being applied to the photocuring resin 10, for example, Norland Co. No. A61, Somers Co. UV-74, etc., the photomask as shown in FIG. 3 A is used. When using proximity or projection exposure using 21,
The resin is pulled in the direction of the arrow X, and then cured and formed into a convex pattern shape as shown in FIG. 3B. In other words, since the photocurable resin has fluidity even after coating, the resin is stretched and cured in the Y direction of the center of the cured area during exposure, and as a result, if the area of the exposed area is small (for example, the coating film thickness is 2 to 3 μm and the exposed area is about 10×20 μm ² ), it becomes a convex lens shape.

Therefore, the structure is similar to that of a convex lens placed on top of a photodiode, and light Z, which did not conventionally enter the photodiode 1, is focused and incident as shown in FIG. 3C, thereby improving the light sensitivity of the element.

After filling the recessed photodiodes 1 and forming a convex resin pattern on each photodiode 1 (FIG. 2 A to D), one of the plurality of photodiodes 1 on which the first color filter component is to be formed is selected. A layer to be dyed, for example, a gelatin pattern 6 for dyeing, is formed on the resin film pattern 10' in a portion corresponding to 1' (FIG. 2E). This gelatin pattern 6 can be formed by applying a mixture of gelatin and ammonium dichromate at a ratio of 9:1 to the entire surface, hardening only the necessary parts by exposing to ultraviolet light, and selectively removing the others. .

Then, this gelatin pattern 6 is immersed in a dyeing solution of a first color, for example, green, to form a green filter component 6G (FIG. 2F).

In addition, as the layer 6 to be dyed, an organic material layer such as casein or PVA can be used in addition to gelatin.

Next, in order to isolate the green filter component 6G, for example, FVR is applied to the entire light receiving surface including the green filter component 6G.
A transparent isolation layer 7 made of (trade name) or the like is deposited (FIG. 2F). Next, a gelatin layer 6' for dyeing is formed only on the photodiode section 1'' where the second color filter component is to be formed, by the same method as described above, and this is immersed in a dyeing solution of the second color, for example, red. It is colored to form a red filter component 6'R (FIG. 2G, H).

Next, after attaching a transparent isolation layer 7' to the entire surface again (FIG. 2H), the same method is repeated, that is, a dyeing gelatin layer 6'' is placed on the photodiode 1'' where the third color filter component is to be formed. This is then immersed in a dyeing liquid of a third color, for example, blue, to be colored to form a blue filter component 6''B.

In this way, as shown in FIG. 2I, a dyed filter, i.e., a color filter, in which green, red, and blue filter components 6G, 6'R, and 6''B are arranged corresponding to each light-receiving portion 1 on the light-receiving surface, respectively. A color solid-state image sensing device is obtained in which the filter 6 is integrally formed.

According to steps E to I in the embodiment of the present invention described above, a transparent resin film pattern 10' is formed in a convex shape so as to fill the concave portion of one part of the photodiode on the light receiving surface, and then a transparent resin film pattern 10' is formed on the resin film pattern 10'. Since the color filter 6 is formed by dyeing, the resin film pattern 10' alleviates the difference in level due to the unevenness of the light receiving surface, thereby avoiding the occurrence of step breakage and cracks in the dyed layer 6, and reducing the peeling and falling off of the filter components. . Moreover, since the surface of the photodiode is protected by the resin film pattern 10' and the layer 6 to be dyed does not come into direct contact with the photodiode, the adverse effect of the layer 6 to be dyed on the device is avoided. Furthermore, as in the case of FIGS. 1A to 1E, the dyed layer 6 is selectively formed only on the photodiode 1 corresponding to each color, and the light around the photodiode is also focused to some extent on the photodiode, so there is no significant positional shift. The layer 6 to be dyed can be easily formed without worrying about deterioration of the device characteristics due to this, and the photosensitivity of the device is also improved. Furthermore, when the dyed layer 6 is selectively dyed, the previously dyed layer 6 is reliably isolated by the isolation layer 7, so that color mixing (bleeding) does not occur and a color filter with good characteristics can be obtained.

In the above embodiment, the present invention is applied to a mixture having a color filter consisting of three colors of green, red, and blue, but it is of course applicable to a case having a color filter consisting of other colors.

[Brief explanation of the drawing]

FIGS. 1A to 1E are cross-sectional views of a conventional color solid-state image sensor for explaining a method of manufacturing the device, and FIGS. 2A to I are illustrating a method of manufacturing a color solid-state image sensor according to an embodiment of the present invention. FIGS. 3A to 3C are sectional views of the same device for explaining in more detail the main parts of the steps shown in FIGS. 2A to I. 1... Photodiode, 3... Shielding part, 4...
Solid-state image sensor, 5... layer to be dyed, 6... color filter, 7... isolation layer, 10... transparent film.

Claims (1)

[Claims] 1. On an element in which a light receiving section and a signal transfer section are formed.
A process of applying a photocurable resin with high light transmittance in the wavelength range of 400 to 700 nm, and using a prescribed photomask and a proximity or projection exposure device to apply the photocurable resin on the light receiving area so that the recesses are covered. A color filter is formed on the light-receiving area by repeating the steps of selectively exposing and curing the photocurable resin, developing and removing the unexposed areas of the photocurable resin with a developer, and forming and dyeing a layer to be dyed. 1. A method of manufacturing a color solid-state image sensor, comprising the step of forming a color solid-state image sensor. 2. The method for manufacturing a color solid-state image sensor according to claim 1, wherein the photocurable resin has fluidity.