JP3036136B2 - Method for forming patterned multilayer interference film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a patterned multilayer interference film applied to a color filter or the like for coloring transmitted light, and more particularly to a method for accurately forming a patterned multilayer interference film having a fine shape. It is.

[0002]

2. Description of the Related Art Conventionally, in the field of image pickup devices such as an image pickup tube and a solid-state image pickup device, a color separation filter has been used as a means for multicoloring an image pickup device.

The main part of this color separation filter is composed of a substrate and a plurality of color filter layers provided in a pattern on the transparent substrate. The color of the color filter layer is, for example, , Three primary colors of red, green and blue light are used.

As such a color filter layer, an organic type color filter layer using a transparent resin colored with a dye of each color and a number of transparent inorganic substances having different refractive indexes are laminated to form a multilayer film. And an inorganic type color filter layer that colors transmitted light by utilizing the interference of light rays incident on the light emitting element. The inorganic type color filter layer has a higher light transmittance characteristic and can improve the sensitivity of the imaging device, but also has a higher weather resistance, although the production cost is higher than the organic type color filter layer. It has the advantage of being excellent in environmental resistance such as light resistance and light resistance, and is therefore preferably used.

[0005] Such an inorganic type color separation filter is generally manufactured by the following method.

That is, first, as a first step, a lift-off material is formed on a substrate. In general, a metal thin film such as copper is used as the lift-off material in order to ensure resistance to a process of forming a multilayer interference film.

Next, as a second step, a resist is applied on the lift-off material and the resist film is patterned. The shape of the remaining resist film is, for example, a negative shape obtained by inverting the pattern shape of the red color filter layer.

Then, as a third step, the lift-off material at the portion exposed from the resist is removed by etching with an etchant to pattern the lift-off material, and then the resist film is peeled off. The shape of the remaining lift-off material is a shape obtained by inverting the pattern shape of the color filter layer,
The portion exposed from the lift-off material has the same shape as the pattern shape of the color filter layer.

Next, as a fourth step, after forming a multilayer interference film on the entire surface including the patterned lift-off material, the patterned lift-off material is dissolved and removed, thereby forming the patterned lift-off material together with the patterned lift-off material. It also removes the multilayer interference film portion laminated on the material. Thus, the remaining multilayer interference film portion is used as a patterned multilayer interference film.

[0010] These steps are repeated for each color filter to form a plurality of multilayer interference films.

As described above, when the first multilayer interference film is formed, the surface (substrate surface) on which the lift-off material is formed is flat, but when the second multilayer interference film is formed, Since the first patterned multilayer interference film formed before that remains on the substrate, irregularities based on the patterned multilayer interference film are formed on the surface.

[0012]

By the way, as higher resolution is required with the development of the technology of the image pickup device, further miniaturization of the pattern of the multilayer interference film is required.

However, in the above method using a metal thin film such as copper as a lift-off material, if the metal thin film has a thickness sufficient to function as a lift-off material, the metal thin film is etched with an etching material. However, since the amount of side etching becomes large, the miniaturization is limited, and there is a problem that it is difficult to meet the above requirements.

As described above, when the second multilayer interference film is formed, the metal thin film used for this is formed on the uneven surface caused by the first patterned multilayer interference film. However, as the first patterned multi-layer interference film becomes finer, the unevenness of the first multi-layer interference film increases, and the unevenness causes cracks or irregularities in the film quality, making it difficult to remove the multi-layer interference film. There was a problem that it was easy to complete.

In the fourth step of dissolving the metal thin film and removing the metal thin film and the multilayer interference film laminated thereon, the time required for completely dissolving the metal thin film is long, For this reason, there has been a problem that the multilayer interference film is damaged to cause a defect or a foreign substance is easily attached.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a method for accurately forming a patterned multilayer interference film having a fine shape.

[0017]

By the way, if a resist film is used as the lift-off material, the resist film does not have side etching, and even if the underlying surface has irregularities of the thickness of the multilayer interference film, the irregularities can be reduced. Irrespective of the above, it can be expected that any of the above-mentioned problems can be solved because the coating can be uniformly formed and the dissolution rate is high and the damage of the multilayer interference film and the attachment of foreign matter are easily prevented.

However, the resist film is generally inferior in resistance to severe conditions in forming a multilayer interference film in which a transparent inorganic thin film is repeatedly formed, so that the multilayer interference film is formed on the patterned resist film. When the film is formed, the resist film expands during the film forming process, the pattern is deformed due to dripping, or the resist film peels off from the substrate and falls off.

Therefore, the present inventors have studied and found that when the surface of the patterned resist film is subjected to plasma treatment,
It has been found that the resistance of the coating is increased to withstand the conditions at the time of forming the multilayer interference film, and that the dissolution performance with respect to the dissolving solution does not substantially change. As the plasma treatment, a plasma treatment using a chlorofluorocarbon gas or an Ar (argon) gas can be used. Among them, in particular, in order to sufficiently secure the suitability for dissolution with a resist solution , Ar (algorithm) is used.
The present inventors have found that plasma treatment with gas is desirable.

According to such technical means, since the surface of the patterned resist film is plasma-treated to increase its resistance, the resistance of the film is increased and the resist film may be damaged. Thus, it is possible to form a multilayer interference film without the need.

Using this resist film as a lift-off material, a patterned resist film is formed on the substrate to selectively expose the substrate where the patterned multilayer interference film is to be formed. After a multilayer interference film is formed, a conventional method using a metal thin film as a lift-off material is used to dissolve the above-described patterned resist film and remove this resist film and the multilayer interference film laminated thereon. No side etching phenomenon.

Further, since the patterned resist film can be formed by a coating method such as spin coating, even if the underlying surface has irregularities of the thickness of the multilayer interference film, uniform coating can be performed irrespective of the irregularities.

As described above, since there is no side etching phenomenon and the resist film can be formed uniformly irrespective of the unevenness of the substrate, it is possible to form a fine patterned resist film with high pattern accuracy. Becomes

In the case of dissolving the patterned resist film, the dissolution rate is much faster than the dissolution rate of the metal thin film, so that damage to the multilayer interference film and adhesion of foreign substances can be prevented. If the residue remains on the substrate even after development,
A solvent or US cleaning may be used in combination.

Further, since the multilayer interference film on the fine patterned resist film formed accurately can be reliably removed without the damage of the multilayer interference film and the attachment of foreign matter, the fine pattern pattern It is possible to accurately form a multilayer interference film.

As described above, the plasma processing includes
A plasma treatment using a Freon gas or an Ar (argon) gas can be used, but a plasma treatment using an Ar gas is preferable in order to sufficiently secure the suitability for dissolution using a resist solution. For example, Ar gas / RIE (reactive ion etching) It can be processed in the same way as the processing method known by the name. Also, this plasma treatment
It can be performed inside a vacuum evaporator applied to multilayer interference film formation, and in this case, plasma processing and multilayer interference film formation can be performed continuously within the same vacuum evaporator. , The manufacturing process can be shortened.

Next, as such a resist film, a heat-resistant resist film which can withstand heat during the formation of the multilayer interference film and is not easily damaged can be preferably used. For example, Fuji having a heat resistance of about 130 ° C. 5600 available from Hunt Corporation.

Next, in the invention according to claim 1, as the multilayer interference film, a known multilayer thin film constituted by alternately laminating a plurality of transparent thin films having a high refractive index and transparent thin films having a low refractive index is used. The multilayer interference thin film can be formed by a known thin film forming method such as a vacuum evaporation method and a sputtering method. In the case where the resist film is formed at a low temperature of 150 ° C. or lower, a uniform multilayer interference film can be formed by preventing the resist film from being damaged.

The invention described in claim 2 has been made based on such technical reasons. That is , the invention described in claim 2 is based on the invention described in claim 1 and is based on a low-temperature deposition method. To form the multilayer interference film. On the other hand, when a film is formed by an ion-assisted vapor deposition method in which a film is formed while irradiating ions, a portion where the film is weakly bonded is sputtered or the surface is compacted by the energy of the ions. And for this,
By increasing the packing density of the film, it is possible to form a film having a high refractive index which is excellent in hardness and strength and does not change optical characteristics due to humidity at a low temperature.

The invention described in claim 3 has been made based on such technical reasons, that is, the invention described in claim 3 is based on the invention described in either claim 1 or 2. Wherein the multilayer interference film is formed by an ion-assisted vapor deposition method.

Next, the invention according to claim 4 clarifies that the multilayer interference film is a color filter.

That is, the invention according to claim 4 is based on the invention described in claim 1, 2 or 3,
The multilayer interference film is a color filter. In addition, as a substrate according to the present invention, an imaging element, a CCD, or the like can be used in addition to a glass substrate.

[0033]

According to the present invention, a patterned resist film is formed on the substrate by using a heat-resistant resist, exposing a substrate portion for forming the patterned multilayer interference film. A first step, and a second step of performing plasma treatment with Ar gas on the surface of the patterned resist film to increase the resistance of the patterned resist film;
After forming a multilayer interference film on the entire surface of the substrate on which the patterned resist film is formed, by dissolving and removing the patterned resist film, together with the patterned resist film, the patterned resist film is formed. A third step of patterning the multilayer interference film by also removing the multilayer interference film laminated thereon, and plasma-treating the surface of the patterned resist film to increase its resistance. Therefore, the resistance of the film is increased, and a multilayer interference film can be formed without damaging the resist film.

Since this resist film is used as a lift-off material and the multilayer interference film laminated thereon is removed, there is no side etching phenomenon seen in the conventional method using a metal thin film as a lift-off material. In addition, since the patterned resist film can be formed by a coating method such as spin coating, even if the underlying surface has irregularities of the thickness of the multilayer interference film, uniform coating can be performed irrespective of the irregularities. Therefore, it is possible to form a fine patterned resist film with high pattern accuracy.

Further, since the dissolution rate of the patterned resist film is remarkably faster than the dissolution rate of the metal thin film, it is possible to prevent damage to the multilayer interference film and adhesion of foreign matter.

Then, the multilayer interference film on the finely patterned resist film formed accurately without damage of the multilayer interference film and adhesion of foreign matter can be surely removed.

According to the second aspect of the present invention, since the multilayer interference film is formed by the low-temperature deposition method, it is possible to prevent damage to the resist film and form a uniform multilayer interference film. Becomes

On the other hand, according to the third aspect of the present invention, since the multilayer interference film is formed by the ion assisted vapor deposition method, the packing density of the film is increased, the hardness and the strength are excellent, and the optical characteristics change due to humidity. It is possible to form a high-refractive-index film free of any defects at low temperatures.

[0039]

Embodiments of the present invention will be described below with reference to the drawings. A color separation filter in which three color filter layers of a green transmission filter layer, a red transmission filter layer, and a blue transmission filter layer were two-dimensionally arranged on a silicon wafer was prepared by the following method.

That is, first, FH5600F (a heat-resistant positive type resist manufactured by Fuji Hunt Co.) is spin-coated to a thickness of 3.4 μm on the entire surface of the silicon wafer (1), and then patterned. As shown in FIG. 1, a resist pattern layer (2a) exposing a part of the silicon wafer was obtained according to a predetermined pattern.

Next, the resist film surface was subjected to RIE treatment with Ar gas to obtain a resist pattern layer (2a ') having increased resistance as shown in FIG.

Next, as shown in FIG. 3, a green low-temperature deposition layer (3) having a thickness of 1.94 μm was formed on the entire surface of the patterned resist film using an ion gun and a nutrizer. Here, the green low-temperature deposited layer is a multilayer interference film of the green transmission filter layer (3), which has formed by low-temperature ion-assisted deposition, the deposition is, 10% of the oxygen in the Ar gas as the ionizing gas Using a mixed gas obtained by mixing gases, a flow rate of 3 SCCM, an acceleration voltage of 0.5 KV,
The test was performed under the condition of an acceleration current of 60 mA.

Then, the remaining resist pattern layer (2
a ′) is dissolved and removed to form a resist pattern layer (2)
a ′), and a green low-temperature deposition layer (3) laminated thereon
The portion was removed, and as shown in FIG. 4, a multilayer interference film to be the green transmission filter layer was selectively formed on the exposed portion. As a solution for dissolving the resist pattern layer (2a '), a microposit remover (manufactured by Shipley Co., Ltd.) heated to 80 ° C. was used.

Next, a red low-temperature deposition layer (4), that is, a red transmission filter layer (thickness: 1.54 μm) is selectively formed in a part of the portion where the green transmission filter layer is not formed by a similar method. Then, FIG. 5 is obtained.

Next, by the same method, a blue low-temperature deposition layer (5), that is, a blue transmission filter layer (1.08 μm thick) is selectively formed on the portion where the green transmission filter layer and the red transmission filter layer are not formed. Was formed to obtain a three-color separation filter 6 shown in FIG.

[0046]

According to the inventions according to the first to fourth aspects, the multilayer interference film on the fine patterned resist film formed accurately without damage to the multilayer interference film and adhesion of foreign matter is reliably removed. Therefore, there is an effect that it is possible to accurately form a patterned multilayered interference film having a fine shape.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view during the formation of an embodiment of a patterned multilayer interference film of the present invention.

FIG. 2 is a cross-sectional view of a patterned multilayer interference film according to an embodiment of the present invention in the course of forming.

FIG. 3 is a cross-sectional view of a patterned multilayer interference film according to an embodiment of the present invention in the course of forming.

FIG. 4 is a cross-sectional view of one embodiment of the patterned multilayer interference film of the present invention.

FIG. 5 is a cross-sectional view of an embodiment of a color separation filter using the patterned multilayer interference film of the present invention in the course of formation.

FIG. 6 is a cross-sectional view of one embodiment of a color separation filter using the patterned multilayer interference film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Silicon wafer 2a ... Resist pattern layer 2a '... Plasma treatment resist pattern layer 3 ... Green low-temperature deposition layer 4 ... Red low-temperature deposition layer 5 ... Blue low-temperature deposition layer 6 ... Color separation filter

Claims (4)

(57) [Claims] 1. A method of forming a patterned multilayer interference film having a predetermined pattern on a substrate, comprising: exposing a substrate portion for forming the patterned multilayer interference film on the substrate with a heat-resistant resist; A first step of forming a patterned resist film, a second step of performing a plasma treatment on the surface of the patterned resist film with Ar gas to increase the resistance of the patterned resist film, After forming a multilayer interference film on the entire surface of the substrate surface side on which the patterned resist film is formed, by dissolving and removing the patterned resist film, together with the patterned resist film, on the patterned resist film A third step of patterning the multi-layer interference film by also removing the multi-layer interference film laminated on the multi-layer interference film. Formation method. 2. The method for forming a patterned multilayer interference film according to claim 1, wherein said multilayer interference film is formed by a low-temperature deposition method. 3. The method for forming a patterned multilayer interference film according to claim 1, wherein the multilayer interference film is formed by an ion assisted vapor deposition method. 4. The method for forming a patterned multilayer interference film according to claim 1, wherein the multilayer interference film is a color filter.