JP2000206322A - Manufacture of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method having an easy and low-cost process and excellent yield, for obtaining a color filter having excellent heat resistance, chemical resistance, size precision or the like. SOLUTION: This method has a characteristic of having a process for forming a negative type colored resist film to be exposed to both (i) and (g) beams on a substrate where a pixel part and an alignment mark are formed, a process for forming a positive type resist film to be exposed to the (i) beam on the negative type colored resist film, a process for positioning the substrate by a pre-alignment mechanism and for exposing the periphery of the alignment mark on the substrate by the (g) beam, a process for giving development to the substrate and for removing selectively the positive type resist film and the negative type colored resist film near the alignment mark, a process for executing the whole face exposure of the positive type resist film on the substrate by the (g) beam, a process for positioning the substrate by using the alignment mark on the substrate and for exposing the negative type colored resist film of the pixel part on the substrate by the (i) beam, and a process for developing simultaneously both the positive type resist film and the negative type colored resist film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a photolithography technique using a negative type colored resist,
For example, the present invention relates to a method for manufacturing a color filter used for an image sensor.

[0002]

2. Description of the Related Art A dyeing method is generally known as a method for manufacturing a color filter used in an image pickup device for color image pickup.

[0003] The dyeing method is a method which has been generally carried out as a practical technique at a mass production level, and includes natural proteins such as gelatin and fish glue, polyacrylamide, and the like.
A dyeable photosensitive substance such as a synthetic resin such as polyvinyl alcohol or polyimide is coated on a glass substrate to form an organic base layer, and a transparent pattern is formed through a photofabrication process of exposure and development. After that, the transparent pattern is immersed in a predetermined dye solution to be dyed, and this process is performed by R (Red), G (Green), B (Blu).
This is a method of forming a colored layer by repeatedly performing the three colors of e). However, in this method, the steps such as dyeing and anti-dyeing treatment are complicated, and the colored layer is liable to fade with respect to temperature and humidity, and has poor reliability in terms of heat resistance, chemical resistance, weather resistance, etc. There was a problem.

[0004] In order to solve these problems, a method of manufacturing a color filter using a colored resist by ordinary photolithography while having excellent heat resistance, chemical resistance, weather resistance, and the like has been studied.

This method is as shown in FIG.

That is, on a semiconductor substrate 1 on which an image pickup device is formed, a negative-type colored resist film 2 that is sensitized only to an i-line (ultraviolet region having a wavelength of 365 nm) is formed.
Alignment of the semiconductor substrate 1 is performed by detecting an alignment mark through the negative colored resist film 2 using a Ne laser (wavelength: 633 nm).

Thereafter, a predetermined color filter pattern is exposed by the photomask 6 (FIG. 3A) and developed (FIG. 3B) to form a color filter of a predetermined color.
This process is repeated for a desired number of colors to produce a color filter.

However, in this method, when B and G colored resists are used, the transmission wavelength centers of these colors are only around B (450 nm) and G (540 nm), respectively, and He-Ne is used. Laser (wavelength 633nm)
However, there is a problem that the method cannot be applied only to R because the light is not transmitted.

[0009]

As described above, conventional methods for producing a color filter by a dyeing method include dyeing,
In addition to the complicated processes such as anti-dyeing treatment, the colored layer is liable to fade with temperature and humidity, and has poor reliability in terms of heat resistance, chemical resistance, weather resistance and the like.

Further, when a color filter is manufactured using a colored resist excellent in these characteristics, the transmission wavelength centers of the G and B colored resists are respectively G (540n).
m) and B (450 nm) only, and a He-Ne laser (6
33 nm) is not transmitted, so that R
There was a problem that only can be applied to.

Therefore, the object of the present invention is to provide R, G, B
An object of the present invention is to provide a method for manufacturing a highly reliable color filter which can be applied to any one of the above colors and can be manufactured by a general photolithography technique.

[0012]

According to a first aspect of the present invention, there is provided a color filter manufacturing method, wherein a green or blue negative type resist film sensitive to only i-line is formed on a substrate on which a pixel portion and an alignment mark are formed. Performing a step of forming a positive resist film that is sensitive to both i and g lines on the negative colored resist film; and positioning the substrate by a pre-alignment mechanism so that the vicinity of the alignment mark of the substrate is g. A step of exposing the substrate to light, a step of developing the substrate to selectively remove the positive resist film and the negative colored resist film near the alignment mark, and an entire surface of the positive resist film of the substrate by g-line. Performing an exposure, positioning the substrate using an alignment mark on the substrate, and exposing a negative-type colored resist film in a pixel portion of the substrate with i-line. And that step, characterized by comprising a step of developing the positive type resist layer and the negative-type colored resist film at the same time.

[0013] The invention according to claim 2 is a step of forming a green or blue negative colored resist film sensitive only to the i-line on the substrate on which the pixel portion and the alignment mark are formed; Forming a positive resist film sensitive to both i-line and g-line on the resist film; and positioning the substrate by a pre-alignment mechanism and exposing the vicinity of the alignment mark of the substrate with g-line. Developing the substrate to selectively remove the positive resist film and the negative colored resist film in the vicinity of the alignment mark; and positioning the substrate using the alignment mark of the substrate to form a pixel portion of the substrate. Exposing the negative-type colored resist film and the positive-type resist film with i-line and simultaneously forming the positive-type resist film and the negative-type colored resist film; Characterized by comprising the step of image.

In the second aspect of the present invention, in the step of exposing the negative colored resist film and the positive resist film in the pixel portion of the substrate with i-line, it is preferable to use a halftone mask as a photomask.

In any of the methods, the exposure of the negative-type colored resist film is performed through the upper positive-type resist film. Therefore, the thickness of the positive-type resist film is desirably small, and is preferably 1 μm or less. It is particularly preferred that there is.

The light used in the present invention is light in the ultraviolet region near the wavelength of 365 nm, which is sensitive only to the i-line.
This is light in the visible region of 36 nm.

The negative type colored resist used in the present invention is a negative type photoresist, for example, a solution in which a pigment of a predetermined color is dissolved in a mixture of an acrylic resin and an initiator, and is effective only for i-line. Has sensitivity. In other words, when the coating is irradiated with i-rays, the irradiated part is cured and loses the solubility in the solvent (developer). Therefore, only the unirradiated portion is dissolved in the solvent and disappears, and a pattern corresponding to the mask pattern is formed.

The positive resist used in the present invention is such that the light-irradiated portion becomes soluble in an alkali solution (developer), for example, a solution obtained by dissolving a novolak resin and a naphthoquinonediazide compound, and And effective sensitivity to g-line. The positive resist of the present invention becomes alkali-soluble when the coating is irradiated with i-line or g-line. Therefore, only the irradiated portion is dissolved and removed by the developer to form a pattern corresponding to the mask pattern. By the way,
The novolak resin itself dissolves in alkali to some extent, but when naphthoquinonediazide is added to the novolak resin, the dissolution rate is greatly reduced. .

The negative colored resist film and the positive resist film are generally formed into a coating film by spin coating, but a dry film may be used depending on the application.

Further, the present invention is particularly suitable for producing a color filter for an image sensor, but is not limited to such a use, and may be used for other uses requiring the same high precision. Of course, it is also possible.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG.

A large number of semiconductor devices were formed in a matrix on one surface of the semiconductor substrate 11, dicing lines were formed between the semiconductor devices, and alignment marks 11a were formed on the dicing lines.

A pigment-dispersed blue colored resist having a predetermined thickness was applied on the semiconductor substrate 11 by spin coating to form a blue colored resist film 12.

The blue colored resist film 12 is of a negative type, has an effective sensitivity only for the i-line, and has no sensitivity for the g-line. Further, a positive type non-colored resist having sensitivity to g-line and i-line is formed thereon as a layer having a thickness of 1 μm or less (0.7 μm or less).
μm) by spin coating to form a positive resist film 13 sensitive to both i-line and g-line.

Next, the semiconductor substrate is set on a g-line stepper (for example, Nikon NSR-1505G6D), the semiconductor substrate is aligned using only a pre-alignment mechanism for detecting the substrate orientation flat of the stepper, and the photomask 14 is set. Then, the alignment mark of the dicing line of the semiconductor substrate was exposed to light (FIG. 1A).

The pre-alignment accuracy of this stepper (Nikon NSR-1505G6D) is 3σ to 25 μm and 100 μm
The positive resist film on the dicing line of the semiconductor substrate 11 having a width of about a degree could be exposed with sufficient accuracy. By this exposure, the positive resist film 13 on the dicing line on the semiconductor substrate 11 is exposed, but the negative blue colored resist film 12 is not exposed because it has no sensitivity to g-line.

For this reason, in the next developing step, the positive resist and the negative colored resist around the dicing line are removed, and the alignment mark 11a is exposed (FIG. 1).
(B)). Further, the semiconductor substrate 1 is formed by a g-line stepper.
1 was exposed to expose the positive resist film 13 on the semiconductor substrate 11 (FIG. 1C).

Next, the semiconductor substrate 11 is set on an i-line stepper, alignment is performed using the substrate alignment mark 11a of the semiconductor substrate 11, and the photomask 14 is formed.
The blue colored resist film 12 in the pixel portion of the semiconductor substrate 11 was exposed to light through (FIG. 1D). Finally, develop
Unexposed portions of the positive resist layer 13 and the blue colored resist film 12 were removed to form a blue color filter.

Hereinafter, a green color filter is formed on the same semiconductor substrate surface by the same method, and a red color filter is formed by the conventional method shown in FIG.
A color filter of three colors of GB was obtained.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, a blue colored resist film 12 and a positive resist film 13 are formed on a semiconductor substrate 11 having a large number of semiconductor devices and alignment marks 11a formed in a matrix on one surface, and a pre-alignment of a g-line stepper is performed. After performing alignment using only the mechanism, exposure is performed on the alignment mark (FIG. 2A), and development is performed to expose the alignment mark 11a (FIG. 2B). Therefore, duplicate description will be omitted.

Next, the semiconductor substrate 11 is set on an i-line stepper, alignment is performed using the substrate alignment mark 11 a of the semiconductor substrate 11, and the blue portion of the pixel portion of the semiconductor substrate 11 is used via the halftone mask 15. The colored resist film 12 was exposed (FIG. 2C). In addition,
The exposure light transmission intensity of 15 parts of the halftone mask is adjusted so that only the positive resist layer is exposed. Finally, development was performed to develop the positive resist layer and the colored resist layer to form a blue color filter.

Hereinafter, a green color filter is formed on the surface of the same semiconductor substrate by the same method, and a red color filter is formed by the conventional method shown in FIG.
A color filter of three colors of GB was obtained.

[0035]

As is apparent from the above description, the method for manufacturing a color filter of the present invention can be applied to any of R, G, and B colors, and can be manufactured by a general photolithography technique. A highly reliable color filter can be provided in terms of heat resistance, chemical resistance, weather resistance, and the like.

[Brief description of the drawings]

FIG. 1 is a process chart schematically showing a manufacturing process according to one embodiment of the present invention.

FIG. 2 is a process chart schematically showing a manufacturing process of another embodiment of the present invention.

FIG. 3 is a process chart schematically showing a conventional color filter manufacturing method.

[Explanation of symbols]

11 Semiconductor substrate 12 Blue colored resist film 13 Positive resist film sensitive to both i-line and g-line 14 Photomask 15 Halftone mask

Claims (5)

[Claims] A step of forming a negative-type colored resist film sensitive to only i-line on a substrate on which a pixel portion and an alignment mark are formed; A step of forming a photosensitive positive resist film, a step of positioning the substrate by a pre-alignment mechanism, and exposing the vicinity of the alignment mark of the substrate with g-line; Selectively removing the negative resist film and the negative resist film; exposing the entire positive resist film of the substrate by g-line; positioning the substrate using alignment marks on the substrate; Exposing the negative-type colored resist film in the pixel portion of the substrate with i-line; and simultaneously developing the positive-type resist film and the negative-type colored resist film And a method of manufacturing a color filter. 2. A step of forming a negative-type colored resist film sensitive to only i-line on a substrate on which a pixel portion and an alignment mark are formed, and forming any of i-line and g-line on the negative-type colored resist film. A step of forming a positive resist film that is also photosensitive, a step of positioning the substrate by a pre-alignment mechanism and exposing the vicinity of the alignment mark of the substrate with g-line, Selectively removing the positive-type resist film and the negative-type resist film; positioning the substrate using an alignment mark of the substrate; and positioning the negative-type resist film and the positive-type resist film in the pixel portion of the substrate by i. Exposing with a line, and simultaneously developing the positive resist film and the negative colored resist film. Method of manufacturing a filter. 3. The color filter according to claim 2, wherein a halftone mask is used as a photomask in the step of exposing the negative color resist film and the positive resist film in the pixel portion of the substrate with i-line. Manufacturing method. 4. The method according to claim 1, wherein said positive resist film has a thickness of 1 μm or less.
A method for manufacturing a color filter described in a groove. 5. The method for manufacturing a color filter according to claim 1, wherein the negative-type colored resist film exposed only to the i-line is colored green or blue.