JP2003156619A - Method for releasing thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To release only a defective color filter formed on a flattening film and further not to adversely affect the flattening film in a color filter substrate of a color liquid crystal display element. SOLUTION: A supporting layer 12 composed of an acrylic resin, a reflecting layer 13 composed of metal such as aluminum, a flattening layer 14 composed of an acrylic resin and a color filter layer 15 consisting of coloring resins of red, green and blue are formed on a glass substrate 11 from the bottom in this order, and in the case in which the color filter layer 15 is judged to be defective in inspection and the defective color filter layer 15 is to be released, the color filter layer 15 is subjected to scanning and irradiation with an electron beam 21. Thereby the color filter layer 15 suffers heat damage and is deteriorated. In this case, the flattening layer 14 can be made to hardly suffer heat damage and not to be deteriorated and only the color filter layer 15 suffering heat damage and being deteriorated is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film peeling method, for example, a thin film peeling method for peeling a thin film formed of a defective color filter layer or the like provided on one substrate of a color liquid crystal display element.

[0002]

2. Description of the Related Art For example, some color liquid crystal display devices have one substrate provided with a color filter layer made of red, green and blue colored resins. By the way, in the color filter layer formed on one of the substrates, defects such as a defect due to mixing of foreign matters such as dust, a defect due to generation of pinholes (color loss), a defect due to generation of protrusions may occur.

In such a case, by removing the defective color filter layer from one substrate and reusing the one substrate without discarding the one substrate on which the defective color filter layer is formed, the low color filter layer is reused. We are working to reduce costs.

As a method for peeling off such a defective color filter layer, one of the substrates is entirely immersed in a color filter layer peeling agent (an aqueous solution containing an alkanediol, a surfactant and an alkali compound). 11-
No. 21483), there is a method by plasma ashing using O2 gas or O2 + CF4 mixed gas.

By the way, as a color filter substrate of a conventional reflection type color liquid crystal display device, as an example, FIG.
There is something like. In this figure, a support layer 2 made of acrylic resin and having a rough surface is formed on a glass substrate 1. On the support layer 2, there is formed a reflective layer 3 made of a metal such as aluminum, which has an uneven surface that follows the uneven surface of the support layer 2.

A flattening film 4 made of acrylic resin is formed on the reflective layer 3. Red, green,
A color filter layer 5 made of a blue colored resin is formed. A pixel electrode 6 made of ITO is formed on the color filter layer 5. An alignment film 7 made of polyimide is formed on the color filter layer 5 including the pixel electrodes 6.

Here, the surface of the support layer 2 is made uneven and the surface of the reflection layer 3 formed thereon is made uneven so that external light is reflected and diffused at the same time, and the brightness is uniform and clear. This is to get a display. Then, a flattening film 4 is formed on the reflective layer 3 in order to correct the unevenness.

When the color filter layer 5 is found to be defective in the inspection after the color filter layer 5 is formed on such a color filter substrate, the defective color filter layer 5 is peeled off by the above peeling method. To do.

[0009]

By the way, below the color filter layer 5 made of a colored resin, a flattening film 4 made of an acrylic resin and a support layer 2 are formed, both of which are organic thin films. Therefore, the peeling method in which the entire one substrate is immersed in the color filter layer peeling agent has a problem in that only the color filter layer 5 cannot be selectively peeled. On the other hand, in the peeling method by plasma ashing using O2 gas or O2 + CF4 mixed gas, there is a problem that the surface of the planarizing film 4 is particularly deformed due to an abnormal increase in processing temperature. An object of the present invention is to reliably peel only the uppermost thin film of a plurality of thin films sequentially laminated on a substrate, and not to adversely affect the thin film below the uppermost thin film. is there.

[0010]

According to a first aspect of the present invention, there is provided a film quality deterioration step of degrading the film quality of at least a part of the uppermost thin film among a plurality of thin films sequentially laminated on a substrate. And a thin film peeling step of peeling the thin film whose film quality is deteriorated. The invention described in claim 2 is the same as the invention described in claim 1,
The thin film to be deteriorated is an organic thin film, and an organic thin film that is not substantially deteriorated is formed thereunder. A third aspect of the invention is characterized in that, in the first aspect of the invention, the film quality deterioration step is a step of causing thermal damage to the thin film deteriorated by electron beam irradiation. The invention according to claim 4 is characterized in that, in the invention according to claim 1, by setting an acceleration voltage of the electron beam, an effective penetration depth into the thin film to be deteriorated is set. Is. According to a fifth aspect of the present invention, in the first aspect of the invention, the film quality deterioration step is a step of causing thermal damage to the thin film which is deteriorated by irradiation of infrared rays converted into microbeams. It is a thing. The invention according to claim 6 is the same as the invention according to claim 1,
The thin film is peeled off immediately after the thin film to be deteriorated is thermally damaged. According to a seventh aspect of the present invention, in the first aspect, the thin film peeling step peels the deteriorated thin film by rolling an adhesive roller on the deteriorated thin film. To do. The invention according to claim 8 is the invention according to claim 1, wherein in the thin film peeling step, an atomic force microscope is moved onto the deteriorated thin film to separate the deteriorated thin film. It is what Claim 9
In the invention described in any one of claims 1 to 8, the uppermost thin film is a color filter layer made of a red, green, and blue colored resin. Then, according to the present invention, among the plurality of thin films sequentially laminated on the substrate, at least a part of the uppermost thin film is deteriorated in its film quality, and only the deteriorated thin film can be peeled off, and Therefore, it is possible to prevent the thin film that is not deteriorated from being adversely affected.

[0011]

FIG. 1 is a partial cross-sectional view of a color filter substrate of a reflective type color liquid crystal display element as an example of an object to be peeled by a thin film peeling method of the present invention. This color filter substrate is the same as that shown in FIG. 7, but again, in FIG.
A support layer 12 made of acrylic resin and having a rough surface is formed on the surface 1. The support layer 12 is provided on the support layer 12.
The reflecting layer 13 made of a metal such as aluminum having an uneven surface that follows the uneven surface of is formed.

A flattening film 14 made of acrylic resin is formed on the reflective layer 13. A color filter layer 15 made of red, green, and blue colored resin is formed on the flattening film 14. When the color filter layer 15 is determined to be non-defective by inspection, a pixel electrode 16 made of ITO is formed on the color filter layer 15 as shown by a chain line in FIG. 1 and includes the pixel electrode 16. An alignment film 17 made of polyimide is formed on the color filter layer 15.

By the way, also in this case, the reason why the surface of the support layer 12 is made uneven and the surface of the reflection layer 13 formed thereon is made uneven is that external light is diffused and diffused at the same time.
This is to obtain a clear color display with uniform brightness. Then, in order to correct the unevenness, the flattening film 14 is formed on the reflective layer 13.

Here, an example of the dimension of the film thickness of each film will be described. The thickness of the support layer 12 is 2.0 to 2.5 μm
The thickness of the reflective layer 13 is about 0.02 to 0.2 μm,
The flattening film 14 has a thickness of about 2.0 to 2.5 μm, and the color filter layer 15 has a thickness of about 1.0 to 3.0 μm.

Next, the case where the color filter layer 15 is determined to be defective in the inspection after the color filter layer 15 is formed on such a color filter substrate and the defective color filter layer 15 is peeled off will be described.

First, as shown in FIG. 2, the glass substrate 11
The entire upper color filter layer 15 is irradiated with an electron beam 21 while scanning as in a scanning line 22 indicated by an arrow. As a device for irradiating the electron beam 21, the accelerating voltage of the electron beam, the primary beam current, and the size of the electron beam probe can be varied, and the glass substrate 11 is held on the upper surface at arbitrary scanning speeds in the XYθ directions. Any stage may be used as long as it has a stage that moves precisely, and for example, an electron beam probe microanalyzer (EPMA) is used.

In this case, since the beam intensity in the outer peripheral portion of the electron beam 21 irradiation region is weaker than that in the central portion, the irradiation energy is made uniform by scanning so that the edges of the beam overlap. For example, when the pitch of the scanning lines 22 is about 45 μm, the electron beam probe size is about 50 μmφ. Then, in the region of the color filter layer 15 irradiated with the electron beam 21, the film quality is damaged by heat and deteriorates.
This deteriorated portion appears to be discolored black when observed with an optical microscope. In this case, as will be described later, only the color filter layer 15 is thermally damaged and deteriorated, and the flattening film 14 thereunder is hardly thermally damaged and is not deteriorated.

Next, as shown in FIG. 3, the adhesive roller 23
By rolling on the color filter layer 15, the entire color filter layer 15 which has been deteriorated due to heat damage is peeled from the flattening film 14 on the glass substrate 11 and transferred onto the surface of the adhesive roller 23. Thus, only the defective color filter layer 15 is reliably peeled off. In this case, in particular,
The flattening film 14 is not damaged by heat and does not deteriorate, so that the surface thereof is not deformed.

Here, it will be described that only the color filter layer 15 is damaged by heat and deteriorates. For example, the organic thin film is made of acrylic resin, and [CH2CH
The composition ratio of (COOH)] n is 64% by weight for C and 33 for O.
% By weight, and 3% by weight in H. When the surface of this organic thin film is vertically irradiated with an electron beam, approximately 95% or more of the irradiated electron beam penetrates into a region (effective penetration depth described later) of the organic thin film, Most (about 99%) of the invading electron beam is consumed as heat and is partially emitted as characteristic X-ray.

In this case, the relationship between the electron beam acceleration voltage and the effective penetration depth of the electron beam is as shown in FIG. 4 according to Monte Carlo simulation. As is clear from this figure, the effective penetration depth of the electron beam is determined by the magnitude of the electron beam acceleration voltage, and the effective penetration depth increases as the acceleration voltage increases. Based on FIG. 4, as an example,
The film thickness of the organic thin film is 2.5 μm, and the acceleration voltage may be set to about 13 kV in order to make the effective penetration depth of the electron beam for the film 2.5 μm.

On the other hand, the saturation temperature of the organic thin film (infinite time)
Is represented by Θ = Q / πKa. Where Q is input power (W / s), π is circular constant, and K is thermal conductivity (cal / cm).
-S-deg), a is a beam radius (cm). Therefore, the beam radius a is set to 25 μm, and the acceleration voltage is 13 kV.
Then, the temperature of the entire organic thin film in the depth direction is the temperature before and after the structural change or decomposition occurs in the entire organic thin film in the depth direction.
The beam current should be 0.0
It may be set to about 1 μA / sec. However, it is necessary to experimentally determine such conditions based on actual samples.

From the above, the thickness of the organic thin film is 2.5.
The accelerating voltage may be set to about 13 kV in order to set the effective penetration depth of the electron beam to 2.5 μm. When the beam radius a is set to 25 μm and the beam current is set to 0.01 μA / sec, the temperature in the entire depth direction of the organic thin film becomes about 300 ° C., and the structural change and decomposition occur in the entire depth direction of the organic thin film. The film quality of the organic thin film is damaged by heat in the entire depth direction and deteriorates. In this case, even in the case of the laminated structure in which the organic thin film is laminated under the organic thin film, if the effective electron beam penetration depth is set at the boundary surface between the two organic thin films, the electron beam hardly penetrates into the lower organic thin film. Therefore, the lower organic thin film is not damaged by heat and does not deteriorate.

As described above, only the defective color filter layer 15 can be reliably peeled off as described above. Further, in particular, since the flattening film 14 is not damaged by heat and does not deteriorate, it is possible to prevent the surface from being deformed.

In the above embodiment, as shown in FIG. 3, the case where the adhesive roller 23 is used to peel off the color filter layer 15 which has been deteriorated due to heat damage has been described. However, the present invention is not limited to this. is not. For example, in FIG.
As shown in, the AFM (Atomic Force Microscope)
Microcope) may be used to peel off the color filter layer 15 that has been deteriorated due to heat damage.

That is, in the AFM in this case, the deep needle / peeling needle unit 31 is provided at the tip of the arm (not shown). The deep needle and peeling needle unit 31 is provided with a piezo element 32 below the tip of the above-mentioned arm.
The support block 33 is provided below the support block 33.
The structure is such that a cantilever 34 is provided below the cantilever 34, a deep needle 35 is provided below the tip of the cantilever 34, and a peeling needle 37 having a micrometer 36 is provided on the support block 33.

When the AFM is used to peel off the color filter layer 15 which has been deteriorated due to heat damage, first, the micrometer 36 is operated to adjust the height of the tip of the peeling needle 37. Color filter layer 15
Set the height according to the film thickness of. Further, the deep needle / peeling needle unit 31 is arranged on the left side of the irradiation area of the electron beam 21 in FIG. However, in this case, in FIG. 2, the scanning of the electron beam 21 is performed in one direction from the left side to the right side. Then,
The deep needle / peeling needle unit 31 follows the scanning of the electron beam 21 and is scanned in one direction from the left side to the right side in FIGS. 2 and 5.

Next, when the deep needle / separation needle unit 31 is lowered to bring the tip of the deep needle 35 closer to the surface of the color filter layer 15, the color filter layer 15 near the surface of the color filter layer 15. Due to the existence of the region in which the atomic force is exerted by the atoms, the tip portion of the deep needle 35 is repulsed by the atomic force and is held at a position slightly apart from the surface of the color filter layer 15.

Then, when the deep needle 35 is scanned in the right direction in FIG. 5 while controlling the piezo element 32 so that the repulsive force due to the atomic force is kept constant in this state, the deep needle 3
The leading end of the reference numeral 5 is vertically displaced along the unevenness of the surface of the color filter layer 15 and is scanned rightward. Then,
The peeling needle 37 follows the scanning of the deep needle 35, and immediately peels the color filter layer 15 which is deteriorated due to heat damage due to the irradiation of the electron beam 21 shown in FIG. 2 from the flattening film 14 on the glass substrate 11. .

In this case, the color filter layer 15 is thermally damaged and deteriorated by the irradiation of the electron beam 21, and immediately thereafter, the color filter layer 15 is thermally damaged and deteriorated.
Since 5 is peeled off, the process time can be shortened. By the way, a microdrill may be used instead of the peeling needle 37.

In the above embodiment, as shown in FIG. 1, the flattening film 14 is formed on the reflective layer 13, the color filter layer 15 is formed on the flattening film 14, and the color filter 15 is formed.
Although the case of peeling is described, the present invention is not limited to this. For example, as shown in FIG.
The color filter layer 15 is formed thereon, and the flattening film 14 is formed thereon. However, before forming the flattening film 14, the color filter layer 15 determined to be defective in the inspection may be peeled off. Good. In this case, the color filter layer 15 is
It is formed as a thin thin film with a film thickness of about 0.4 to 0.7 μm so as to be formed in an uneven shape following the uneven surface of the reflective layer 13.

In the above embodiment, the case where the color filter layer is damaged by heat and deteriorated by irradiating while scanning the electron beam has been described, but the invention is not limited to this. For example, the color filter layer may be damaged by heat and deteriorated by irradiating while scanning the infrared rays in the form of minute beams.

In the above embodiment, the case where the defective color filter layer is completely peeled has been described. However, the present invention is not limited to this, and only the defective portion of the defective color filter layer may be peeled off. The color filter substrate to be peeled off may be a color filter substrate of a semi-transmissive reflective type color liquid crystal display element if the reflective layer 13 is a transflective layer in FIG. 1 or 6. Further, the object to be peeled off is not limited to the color filter layer, and the point is that the thin film including at least a part of the uppermost thin film among the plural thin films sequentially laminated on the substrate may be peeled off.

[0033]

As described above, according to the present invention, among a plurality of thin films sequentially laminated on a substrate, at least a part of the uppermost thin film is deteriorated by deteriorating its film quality. It is possible to surely peel only the thin film, and it is possible to prevent the thin film that is not deteriorated from being adversely affected.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a color filter substrate of a reflective type color liquid crystal display element as an example of an object to be peeled by a thin film peeling method of the present invention.

FIG. 2 is a perspective view shown for explaining a case of irradiating a defective color filter layer with an electron beam.

FIG. 3 is a perspective view shown for explaining an example of peeling a defective color filter layer that has been deteriorated due to heat damage.

FIG. 4 is a diagram showing a relationship between an electron beam acceleration voltage and an effective penetration depth of an electron beam into an organic thin film.

FIG. 5 is a cross-sectional view for explaining another example in the case of peeling a defective color filter layer that has been deteriorated due to heat damage.

FIG. 6 is a partial cross-sectional view of another example of the color filter substrate.

FIG. 7 is a partial cross-sectional view of an example of a color filter substrate of a conventional reflective color liquid crystal display element.

[Explanation of symbols]

11 glass substrate 12 Support layer 13 Reflective layer 14 Flattening film 15 Color filter layer

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Claims (9)

[Claims] 1. A film quality deterioration step of degrading the film quality of at least a part of the uppermost thin film among a plurality of thin films sequentially laminated on a substrate, and a thin film peeling for peeling the thin film whose film quality has been degraded. A method for peeling a thin film, which comprises: 2. The method for peeling a thin film according to claim 1, wherein the thin film to be deteriorated is an organic thin film, and an organic thin film which is not substantially deteriorated is formed thereunder. 3. The thin film peeling method as claimed in claim 1, wherein the film quality deterioration step is a step of causing thermal damage to the thin film deteriorated by electron beam irradiation. 4. The method for peeling a thin film according to claim 1, wherein an effective penetration depth for the thin film to be deteriorated is set by setting an acceleration voltage of the electron beam. 5. The method for peeling a thin film according to claim 1, wherein the film quality deterioration step is a step of causing thermal damage to the thin film which is deteriorated by irradiation of infrared rays converted into microbeams. . 6. The thin film peeling method as claimed in claim 1, wherein the thin film is peeled immediately after the thin film to be deteriorated is thermally damaged. 7. The peeling of a thin film according to claim 1, wherein the thin film peeling step peels the deteriorated thin film by rolling an adhesive roller on the deteriorated thin film. Method. 8. The thin film peeling step according to claim 1, wherein the thin film peeling step peels the deteriorated thin film by moving an atomic force microscope on the deteriorated thin film. Peeling method. 9. The method for peeling a thin film according to claim 1, wherein the uppermost thin film is a color filter layer made of red, green and blue colored resins.