JPH0466902A - Color filter and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color filter for a solid-state imaging device, typified by a CCD (charge-coupled device), used in the heart of a color television camera such as a VTR, and a method for manufacturing the same. Regarding
Specifically, the present invention relates to a color filter in which an inorganic compound film is formed as an antireflection film on the back surface of the filter layer in a type in which a color separation filter layer is directly provided on the light receiving part of a solid-state image sensor, and a method for manufacturing the same.

[Prior Art] Conventionally, the structure of this type of color filter was such that a filter layer was only formed on one side of a transparent glass substrate (the side opposite to the incident light), and the back side of the filter layer was the transparent glass substrate itself. Ta. However, a portion of the incident light that reaches the filter is reflected on the transparent glass substrate,
This resulted in a reduction in the effective amount of light reaching the filter layer or solid-state image sensor.In order to improve this, a method was developed to form an antireflection layer by vapor depositing an inorganic compound on the opposite side of the filter layer in a vacuum atmosphere. Unexamined Japanese Patent Publication 1986-
It is disclosed in Japanese Patent No. 124901.

[Problems to be Solved by the Invention] In the conventional method described above, an antireflection film is formed by a vacuum evaporation method or a sputtering method. However, according to the vacuum evaporation method, a thin film formed at a low temperature has a low refractive index. It is difficult to improve reflectance characteristics. However, if the thin film is formed at high temperatures, there is a problem in that the properties of the filter layer deteriorate. Furthermore, according to the sputtering method, since the film thickness is controlled by time, the film thickness varies due to slight variations in conditions, resulting in poor reproducibility.

The present invention was made in view of such conventional problems,
The object of the present invention is to provide a color filter in which a thin film with good properties is formed at low temperatures and an antireflection layer with excellent reproducibility, and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above object, the color filter of the present invention includes a color separation filter layer formed in a desired pattern with at least a predetermined number of colors on one side of a transparent glass substrate. An antireflection layer obtained by ion beam assisted vapor deposition of an inorganic compound in a vacuum atmosphere is provided on the opposite side of the color separation filter layer of a glass transparent substrate.

In addition, in order to achieve the above object, the method for producing a color filter of the present invention includes forming at least a color separation filter layer on one side of a glass transparent substrate in a desired pattern with a predetermined number of colors; The structure is such that an antireflection layer obtained by ion beam assisted vapor deposition of an inorganic compound in a vacuum atmosphere is formed on the surface of the substrate opposite to the color separation filter layer.

[Function] According to the present invention, by forming the antireflection layer by ion beam assisted vapor deposition, a thin film of the antireflection layer that improves reflectance characteristics can be formed at low temperature with good reproducibility. Since the thin film is formed at a low temperature, the characteristics of the color separation filter layer do not deteriorate.

[Detailed description of the invention] The present invention will be explained in detail below.

FIG. 1 is a sectional view showing the structure of an embodiment of a color filter of the present invention.

The glass transparent substrate 1 has a thickness of about 0.5 to 1.0 mm, and is made of ordinary glass such as quartz glass, low expansion glass, borosilicate glass, or soda lime glass. A filter layer 2 for color separation is provided on one side of such a glass transparent substrate 1. The filter layer 2 is disclosed in Japanese Patent Publication No. 52-17375 and Japanese Patent Publication No. 52-17375.
As known in Japanese Patent No. 17376, there is an organic resin filter layer in which a thin film of a water-soluble resin photosensitive material such as gelatin, low molecular weight gelatin, or glyucasein is photocured and dyed with a dye. i O2~3
Naturally, an inorganic interference filter layer formed by alternately stacking about 10 to 20 high refractive index thin films and low refractive index thin films as exemplified by i0z can also be used.

The filter layer 2 has a thickness of about 10μ or less, and has a desired number of colors, for example, two of cyan and yellow.
The colors or three colors such as red, green, and blue as shown in FIG. 1 are provided in accordance with a desired pattern, that is, the shape of the light receiving portion of the solid-state image sensor.

An overcoat layer 4 is provided on the upper surface of the filter layer 2 to protect the surface of the filter layer 2.

In addition, although not shown in FIG. 1, the side surface of the filter may be appropriately coated with an organic material or metal film called a light-shielding layer.

On the back surface of the color filter shown in FIG. 1, an inorganic compound film is provided as an antireflection layer 3 by ion beam assisted vapor deposition. The materials of this thin film are magnesium fluoride (MgFz), silicon dioxide (SiO2),
Alumina (Affi203).

Titanium oxide (T iOJ ), zirconium oxide (Zr0
2) etc. These are appropriately selected depending on the refractive index of the glass transparent substrate 1 and the desired antireflection rate.
It may be a single single layer film or a multilayer film combining several types.

When the filter layer 2 is an organic resin-based thin film obtained by photo-curing a photosensitive material of a water-soluble resin such as gelatin, gryu, or casein and dyeing it with a dye, the heat-resistant temperature is 150°C or lower, so conventional vacuum evaporation methods, In the sputtering method, magnesium fluoride (MgF2) is the most suitable single-layer antireflection coating.
is unsuitable because it requires a temperature of 300°C or more during vapor deposition; in this case, silicon dioxide (which can form a thin film even at low temperatures) is unsuitable.
Sio, ).

Alumina (izos), titanium oxide (Tie, ).

A combination of materials such as zirconium oxide (Z ro 2) was used, but as mentioned above, the refractive index characteristics of the thin film formed at low temperatures were poor and it was difficult to improve the reflectance characteristics.

In contrast, in the present invention, a thin film having good refractive index characteristics, that is, the reflectance characteristics can be improved even at low temperatures, is formed by ion beam assisted vapor deposition.

The ion beam assisted deposition method is a thin film formation method using an ion gun that applies energy of ~2000 eV to active or inert gas ions generated inside the ion gun and irradiates the substrate. Immediately before deposition, the substrate surface is cleaned with active or inert gas ions to improve the adhesion of the thin film, and then the surface of the thin film being formed is irradiated with ions, and the energy of these ions makes it possible to It is possible to form thin films with optical, electrical, and mechanical properties that cannot be obtained, and by irradiating the thin film surface with ions after vapor deposition, the optical, electrical, and mechanical properties of the thin film can be improved. It is possible to change the The ion beam assisted vapor deposition method is described in the 5th Thin Film School Materials of the 131st Committee of the Japan Society for the Promotion of Science (1986, 720-22), pages 113-121.

For example, color filters for solid-state image sensors are disclosed in Japanese Patent Application Laid-Open No. 1983-1989.
As described in Japanese Patent No. 124901, in the filter manufacturing stage, many filter layers are formed on the top surface of one large transparent substrate, and an overcoat layer and a filter layer are formed on the top surface of one large transparent substrate. A method is adopted in which the antireflection layer is formed on the back surface of the substrate and then cut one by one, but such a manufacturing method can also be adopted in the present invention.

[Example] Specific examples of the present invention will be shown below.

E8 glass with a thickness of 0.4 m + n and a diameter of 4' (manufactured by Ohara)
= 1.525) by a known method, and then a four-layer dielectric multilayer film consisting of T io 2 / S io 2 as shown in Fig. 2 was formed using an ion beam assisted vapor deposition device. . The thickness of each layer is 1/
4λ (λ = 550nm) as 1 and 0 in order from the substrate.
．． 24 (T 1oz), 0.36 (S io2
), 2. OO (Ties) 1.00 (S io 2
).

First, the substrate on which the color filter was formed was set in a vacuum device with the glass surface facing the evaporation source, and the substrate was heated at 120° C. and evacuated to 8×10 −′ mbar.

The deposition was carried out in an oxygen atmosphere of 4 x 10-' mbar, with an ion energy of 60 eV and an Ar10. The gas flow rate was 35 CCM.

As shown in Figure 3, the reflectance of the anti-reflection film formed by the above method is about 5 to 6% compared to the 9% reflectance of glass.
This is an improvement of 3-4%.

[Effects of the Invention] As explained in detail above, the color filter of the present invention has an anti-reflection layer formed on the opposite side of the filter layer, which can suppress the reflection of light that reaches the filter. Approximately 1 to 4% of the amount of light that was previously reflected will now reach the filter layer, making it possible to use the light effectively.

Further, in the present invention, since the antireflection layer is formed by ion beam assisted vapor deposition, it is possible to form a thin film of the antireflection layer having good refractive index characteristics at a low temperature in order to improve the reflectance characteristics. Moreover, the reproducibility is good. Furthermore, since the thin film can be formed at a low temperature in this manner, the properties of the color separation filter layer will not deteriorate during the thin film formation.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing the structure of an embodiment of the color filter of the present invention, and FIG. 3 is a graph showing a comparison of reflectance characteristics between the present invention and a conventional product. 1... Glass transparent substrate 2... Filter layer for color separation 3... Antireflection layer 4... Overcoat layer

Claims (2)

[Claims] (1) A color separation filter layer formed in a desired pattern with at least a predetermined number of colors is provided on one side of a glass transparent substrate, and an inorganic compound is placed in a vacuum atmosphere on the opposite side of the glass transparent substrate from the color separation filter layer. A color filter characterized by having an antireflection layer obtained by ion beam assisted vapor deposition underneath. (2) After forming at least a color separation filter layer in a desired pattern with a predetermined number of colors on one side of the glass transparent substrate, an inorganic compound is applied to the opposite side of the glass transparent substrate from the color separation filter layer in a vacuum atmosphere. A method for producing a color filter, comprising: forming an antireflection layer obtained by ion beam assisted vapor deposition.