JPH0459603B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention forms a metal light-shielding layer by electroless plating on the side surface to block unnecessary light from the outside and prevent optical flare and fogging phenomena as a solid-state image sensor camera. The present invention relates to a method of manufacturing a color separation filter for a solid-state image sensor.

Solid-state imaging devices, represented by CCDs (charge-coupled devices), are used at the heart of television cameras. In some cases, a separately prepared color separation filter is attached to the solid-state image sensor. At present, the latter bonding method is the mainstream because of low manufacturing yields for filters and elements. In the lamination method, the color separation filter is
It is formed on a transparent glass substrate with a certain thickness (for example, about 0.5 to 1.0 mm), and as a result, unnecessary light enters from the side of the color separation filter, causing optical flare and causing fog on the camera. tended to occur.

FIG. 1 shows an explanatory diagram of a solid-state imaging device using a conventional color separation filter (no light-shielding layer on the side surface).

According to this, a color separation filter 2 is bonded to the light receiving portion (upper surface) of the CCD 1 with the filter layer in contact with the adhesive layer 3 interposed therebetween. The CCD 1 is configured to transmit electrical signals related to images to the outside of the solid-state image sensor package 6 via conductive wires 4 and lead frames 5. A light beam passing through a camera lens system (not shown) is incident on this solid-state imaging device, and a flare prevention plate 8 is provided on the lower surface of the sealing glass plate 7 around the periphery, as shown in the figure. It is designed to block unnecessary light that enters diagonally from the outside.
When a light ray enters from an angle, the light ray enters from the side of the transparent substrate 9 of the color separation filter 2, causing flare and fogging phenomena, and the flare prevention plate 8 is necessary to prevent this. .

Such a flare prevention plate 8 is a sealing glass plate 7.
It is necessary to align and bond the sensor before attaching it, which not only requires time and effort, but also has become extremely difficult due to the miniaturization of solid-state imaging devices in recent years. It is becoming.

In view of the above-mentioned drawbacks of the conventional technology, the present invention provides a color for a solid-state image sensor having a structure in which a metal light-shielding layer is formed by electroless plating only on the side surface of a transparent substrate, eliminating the need for the above-mentioned flare prevention plate. A method for manufacturing a decomposition filter is provided.

Specifically, after forming at least a large number of color separation filter layers in a desired pattern with a predetermined number of colors on the top surface of a single transparent substrate, a protective film is applied to the top surface of the color separation filter layers, and a glass transparent substrate is formed. A stretchable film membrane is pasted on the lower surface of the substrate, cutting grooves reaching the stretchable film membrane are formed between each color separation filter layer, and then the cutting grooves are formed by spreading the stretchable film membrane on both sides. Then, a metal light-shielding film consisting of an electroless plating layer of metal or alloy is formed on the entire surface of the color separation filter layer side, and then the protective film and the stretchable film are peeled off. It is something to do.

Here, a detailed explanation will be given with reference to FIG. 2 showing an embodiment of a color filter for color separation obtained by the manufacturing method of the present invention. It has a thickness, and the material used is ordinary glass such as quartz glass, low expansion glass, borosilicate glass, or soda lime glass.

A filter layer 11 for color separation is provided on one side of such a glass transparent substrate 10. The filter layer 11 is described in Japanese Patent Publication No. 52-17375 and Japanese Patent Publication No. 17375
As is known from Japanese Patent No. 52-17376, there is an organic resin filter layer in which a thin film of a water-soluble resin photosensitive material such as gelatin, gryu, or casein is photocured and dyed with _a dye.
Of course, an inorganic interference filter layer formed by alternately stacking about 10 to 20 high refractive index thin films and low refractive index thin films such as -SiO ₂ can also be used.

The filter layer 11 has a thickness of about 10 μm or less, and in FIG. 2, its thickness is greatly exaggerated compared to the transparent substrate 10.
Moreover, although it is not clear from Fig. 2, the desired number of colors, for example two colors cyan and yellow, or three colors such as red, green and blue, corresponds to the desired pattern, that is, the shape of the light receiving part of the solid-state image sensor. This is what is provided. In many cases, not only the filter layer 11 for color separation but also an overcoat layer for protecting the surface of the filter layer 11 is added to one side of the transparent substrate 10, or the gaps and surrounding areas of the filter layers of each color are added. There are few examples of color separation filters consisting only of a filter layer 11 and a transparent substrate 10. However, such additional elements for filter layer 11 are conventionally known, and it goes without saying that the present invention applies to all of these conventionally known color separation filters.

A metal light-shielding layer 12 is provided on the side surface of the color separation filter shown in FIG. 2 by electroless metal plating. The material of the metal light shielding layer 12 includes a single plating layer of metal selected from nickel, chromium, cobalt, iron, copper, gold, etc., as well as a combination of nickel-iron, cobalt-iron, copper-iron, etc. An electroless plated layer of an alloy selected from: In addition, metals such as copper are electrolessly plated,
Thereafter, the surface may be subjected to chemical treatment or oxidation treatment to form a metal compound, thereby forming a metal light-shielding layer with low light reflectance on the surface.

The metal light shielding layer 12 has a concentration of 2.0 on a Macbeth densitometer.
It is good to have high light blocking performance with a concentration of
In this sense, it is convenient to use metal as the light shielding layer.

The method for manufacturing a color separation filter for a solid-state image pickup device according to the present invention will be described in detail below with reference to FIGS. 3a to 3e of the drawings showing the process side.

As shown in FIG. 3a, the color separation filter for a solid-state image sensor is manufactured by forming a large number of color separation filter layers 10 on the upper surface of a single transparent substrate 10a, which is called "multi-layering". form,
After that, there is a step of cutting each piece. Immediately before this cutting, as shown in FIG. 3a, a protective film 13 is applied to the H side on which the color separation filter layer 11 is formed by multi-sided application to cover the filter layer 11, and the lower side is coated with, for example, an adhesive layer. A stretchable film 15 such as a vinyl chloride resin film having 14 is attached.
FIG. 3b shows a state in which cutting grooves 16 have been formed between each color separation filter layer 11 using a dicing device or the like. As is already clear, the protective film 13 is
This prevents the filter layer from being contaminated by the cutting coolant and glass debris generated during cutting. Subsequently, as shown in FIG. 3c, force is applied to spread the stretchable film 15 on both sides as shown by the arrows in the figure, thereby enlarging the width of the cutting groove 16 and forming the groove 16'. shall be. In this state, each color separation filter 1 is cut into pieces.
8, the distance between the sides is widened, making it easier to clean this area. In this state, a series of steps known as electroless plating, ie, cleaning, degreasing, sensitization, activation, and plating operations are carried out. Regarding electroless plating, basically, conventionally known electroless plating methods for metals and electroless plating methods for alloys can be used.

However, since the color separation filter according to the present invention requires a post-processing process to bond it to the solid-state image sensor, the metal light-shielding layer formed by electroless plating on the side surface must be attached to the side surface with strong adhesive force. is desirable. For this purpose, a plating method with high adhesive strength to the glass surface may be selected as the electroless plating method.

As an example, in the case of nickel electroless plating method,
After degreasing, sensitization, and activation, treatment with an aqueous solution of an alkali metal salt of hypophosphorous acid such as sodium hypophosphite or potassium hypophosphite is performed before the main operation of electroless plating. By applying electroless plating, the electroless plating layer 1 of metal or alloy can be formed as shown in Fig. 3d.
7 is formed on the entire surface of the protective film 13 and side surfaces of the color separation filter 18.

After this, a stretchable film membrane 15 having an adhesive layer is formed.
If the individual color separation filters 18 are peeled off, and then the stretched film 13 is also peeled off along with the metal light-shielding layer using an adhesive tape, as shown in FIG. 3e,
Individually separated color separation filters 18, each having a metal light-shielding layer 1 formed by electroless plating on its side surface.
2 is formed.

Examples of the present invention will be described below.

Example 1 On a transparent substrate made of Pyrex glass (manufactured by Corning, USA) with a thickness of 0.5 mm and a diameter of 10 cm,
36 square filter layers each approximately 10 mm on a side are applied on multiple sides using a known method, and a coating material that forms an easily removable coating film on the surface filter side is coated with ``Silitecto: a product name manufactured by Controlline, Inc., USA.'' Apply and dry to form a protective film. Next, the stretchable tape SPV-224 (trade name manufactured by Nitto Denko Corporation), which is a stretchable polyvinyl chloride film with an adhesive layer on one side, is pasted to the lower surface of the transparent substrate, as shown in Figure 3a of the drawing. shall be. Subsequently, cutting grooves were cut from the surface using a cutting machine using a 450-mesh resin blade, and the ends of the stretch tape were pulled to form the state shown in FIG. 3c. Next, the surface that had been degreased and washed with water was soaked for 4 minutes in an aqueous solution (25°C) of 5 g of stannic chloride and 5 ml of 35% hydrochloric acid dissolved in 1 part water.
After sensitization treatment and washing with running water for 10 seconds,
Activation treatment was carried out by immersing it in an aqueous solution of 0.1 g of palladium chloride (pdCl ₂ ) and 0.2 ml of hydrochloric acid dissolved in 1 part of water at room temperature for 4 minutes. After rinsing with water, electroless plating was performed by immersing the film at a temperature of 50° C. for 10 minutes using Nippon Kanzen Co., Ltd.'s product name "Shimomar S-680" as an electroless nickel plating solution. After washing with water, at 80℃
Dry with hot air for 30 seconds, peel off the stretchable tape that was attached to the back of the color separation filter, and apply Sellotape (trade name of Nichiban Co., Ltd.) to the surface of the color separation filter to remove the protective film on the surface. By peeling off the surface protective film together with the electroless plating layer thereon, a color separation filter for a solid-state imaging device was obtained in which the electroless plating layer of nickel was applied only to the side surfaces. This electroless plating layer of nickel had a value of 5±0.5 using a Macbeth densitometer, and its adhesive strength was also satisfactory.

Example 2 In exactly the same manner as in Example 1, a multilayered filter layer was formed on a transparent substrate and brought into the state shown in FIG. The same procedure as in Example 1 was carried out, followed by activation treatment. Thereafter, by using electroless plating solutions for the main metals shown below, an electroless plating layer made of each metal or alloy is formed on the side surface to create a color separation filter for solid-state imaging devices as a light-shielding layer. I got it. For both light shielding layers, the concentration value measured by the Macbeth densitometer was 3.0.
That's all.

A Electroless copper plating solution Copper sulfate 35g / Potassium sodium tartrate 173g / Sodium hydroxide 50g / 37% formaldeide 100ml added PH = 11.5, solution temperature 24℃, immersion time 15 minutes B Electroless cobalt plating solution Cobalt sulfate 0.07 mol／ Sodium hypophosphite 0.2mol／ Sodium citrate 0.2mol／ Ammonium sulfate 0.6mol／ PH=9.5, liquid temperature 90℃, immersion time 20 minutes C Electroless nickel-iron alloy plating liquid Nickel chloride 0.056mol／ Sulfuric acid No. Monoferrous ammonium 0.020 mol / Sodium potassium tartrate 0.2 mol / Sodium hypophosphite 0.094 mol / Aqueous ammonia 3.6 mol / Liquid temperature 75°C, immersion time 20 minutes As explained above, the color separation filter of the present invention is made of one piece. When a filter layer for color separation is formed on a glass transparent substrate by multi-sided deposition, an electroless plating process is additionally set in the cutting process to form a layer on the desired area of the side surface of the filter. The metal light-shielding layer can only be applied to the metal light-shielding layer, and the simplicity of the manufacturing method can only be said to be of great industrial advantage.

FIG. 4 shows the color separation filter for a solid-state imaging device according to the present invention incorporated into a CCD type solid-state imaging device. As is clear from the figure, since the metal light-shielding layer 12 is on the side, there is no need to provide a flare prevention plate in the solid-state imaging device, and the solid-state imaging device can be manufactured very easily.

As described above, the method for manufacturing a color separation filter of the present invention is extremely excellent in practical use, as it is simple to manufacture and convenient to incorporate into a fixed imaging device.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a conventional solid-state imaging device, FIG. 2 is a schematic sectional view showing an embodiment of a color separation filter for a solid-state imaging device according to the present invention, and FIGS. FIG. 1 is a cross-sectional view showing an example of the method for manufacturing a color separation filter of the present invention in the order of steps;
FIG. 4 is an explanatory diagram showing how the color separation filter according to the present invention is incorporated into a solid-state imaging device. 10...Transparent substrate, 11...Filter layer, 1
2...Metal light shielding layer.

Claims (1)

[Claims] 1. After forming at least a large number of color separation filter layers with a predetermined number of colors and a desired pattern increase on the top surface of one transparent substrate, a protective film is applied to the top surface of the color separation filter layer, and a protective film is applied to the bottom surface of the glass transparent substrate. A stretchable film membrane is pasted, and cutting grooves reaching the stretchable film membrane are formed between each color separation filter layer.
Thereafter, the width of the cutting groove is expanded by spreading the stretchable film on both sides, and then a metal light-shielding film made of an electroless plated layer of metal or alloy is formed on the entire surface of the color separation filter layer side. A method for manufacturing a decomposition filter for a solid-state imaging device, characterized in that, by subsequently peeling off the protective film and the stretchable film, a metal light-shielding layer is formed by electroless plating only on the side surface of the transparent substrate.