JP5223594B2 - Manufacturing method of flat display panel - Google Patents

Description

  The present invention relates to a method for manufacturing a flat display panel such as an organic electroluminescence (EL) display panel, a liquid crystal display (LCD) panel, or a plasma display panel (PDP).

When manufacturing flat display panels such as an organic EL display panel, a liquid crystal display (LCD) panel, a plasma display panel (PDP), etc., heat treatment is performed for the purpose of forming a display element on a glass substrate. For example, when manufacturing an organic EL display panel, heat treatment is performed at a temperature of 600 to 800 ° C. for the purpose of crystallizing the deposited silicon. When manufacturing an LCD panel, a heat treatment at a temperature of 250 to 450 ° C. is performed in a film forming process for the purpose of forming a thin film transistor (TFT) for driving the LCD panel on a glass substrate. The When manufacturing a PDP, heat treatment is performed at a temperature of 450 to 650 ° C. for the purpose of forming a plasma light emitting cell.
The problem is that compaction (heat shrinkage) generated in the glass substrate during the heat treatment performed for the purpose of forming display elements on these glass substrates adversely affects the display quality of the flat display panel to be manufactured. Yes. The compaction referred to here is the heat shrinkage of the glass caused by the relaxation of the glass structure during the heat treatment, and the degree of compaction is expressed by the heat shrinkage rate of the glass. A method for calculating the compaction will be described in an example described later.

  As a method for reducing the compaction of the glass substrate in the manufacturing process of the p-Si TFT (polycrystalline silicon base TFT), the glass substrate is preliminarily heat-treated (hereinafter referred to as “pre-annealing”) at a temperature similar to the temperature at which the glass substrate is heat-treated. (See Patent Document 1).

International Publication WO2007 / 095115 Pamphlet

However, the present inventors have found that the method of reducing the compaction of the glass substrate by pre-annealing at a temperature similar to the temperature at which heat treatment is performed has the following problems.
(1) Depending on the physical properties (specifically, thermal characteristics) of the glass, compaction cannot be sufficiently reduced, and the display quality of the manufactured flat display panel may be adversely affected.
(2) Further, depending on the pre-annealing time, the compaction cannot be sufficiently reduced, which may adversely affect the display quality of the manufactured flat display panel.
(3) Further, depending on the cooling conditions after pre-annealing, the compaction cannot be sufficiently reduced, and the display quality of the manufactured flat display panel may be adversely affected.
In order to solve the above-described problems of the prior art, the present invention can reduce the compaction generated in the glass substrate during heat treatment performed for the purpose of forming a display element on the glass substrate, and is manufactured. An object of the present invention is to provide a method for manufacturing a flat display panel that does not adversely affect the display quality of the flat display panel.

As a result of diligent studies to achieve the above object, the inventors of the present application formed a display element on a glass substrate in order to reduce the compaction to such an extent that the display quality of the manufactured flat display panel is not adversely affected. The present inventors have found that it is necessary to set pre-annealing conditions corresponding to the heat treatment conditions performed for the purpose.
The present invention has been made on the basis of the above knowledge, and includes a step of pre-annealing a glass substrate and a heat treatment step performed for the purpose of forming a display element on the glass substrate. A manufacturing method comprising:
The temperature after raising the temperature of the glass substrate in the heat treatment step is T ₁ (° C.) (where T ₁ is not less than the strain point Ts (° C.) of the glass substrate and not more than the annealing point Ta (° C.)), the glass substrate. ^Is maintained at T ₁ (° C.) for t ₁ (h) (where t ₁ ≧ 10 ^{(1.518 log η−20.3 −c / 100)} , where η is the temperature of the glass at T ₁ (° C.). Viscosity (dPa · s), c is a target value (acceptable upper limit) (ppm) of compaction generated in the glass substrate during the heat treatment step, and the glass substrate is heated to 200 ° C. from T ₁ (° C.). The cooling rate when cooling to r ₁ (° C./min)
The temperature after raising the temperature of the glass substrate in the pre-annealing step is T ₂ (° C.), the time for holding the glass substrate at T ₂ (° C.) is t ₂ (h), and the glass from the T ₂ (° C.) When the cooling rate when cooling the substrate to 200 ° C. is r ₂ (° C./min),
A flat display panel manufacturing method is provided, wherein the pre-annealing step is performed so as to satisfy the following (1) to (3).
T ₂ = T ₁ (1)
r ₂ = r ₁ (2)
t ₂ ≧ t ₁ (3)

  According to the flat display panel manufacturing method of the present invention, the compaction generated in the glass substrate during the heat treatment performed for the purpose of forming the display element on the glass substrate is adversely affected on the display quality of the flat display panel manufactured. It can be reduced to a certain extent. For this reason, the flat display panel manufactured by the method of the present invention is expected to be excellent in display quality. In addition, it can contribute to the reduction of the manufacturing cost, such as shortening the time of the exposure correction process at the time of film formation in the photolithography process and eliminating the need for a correction mask.

Hereinafter, the manufacturing method of the flat display panel of this invention is demonstrated.
The flat display panel manufacturing method of the present invention includes a step of pre-annealing a glass substrate (hereinafter, referred to as “pre-annealing step”) and a heat treatment step (hereinafter, referred to as “pre-annealing step”) for the purpose of forming a display element on the glass substrate. A heat treatment step). Here, the heat treatment step is a procedure that is usually performed when manufacturing a flat panel display panel, and the specific purpose of the heat treatment varies depending on the type of the flat display panel. For example, when manufacturing an organic EL display panel, heat treatment is performed for the purpose of crystallizing the deposited silicon. When manufacturing an LCD, a heat treatment is performed in a film forming process performed for the purpose of forming a thin film transistor (TFT) for driving an LCD panel on a glass substrate. When manufacturing a PDP, a heat treatment is performed for the purpose of forming a plasma light emitting cell.

In the flat display panel manufacturing method of the present invention, the temperature T ₁ (° C.) after the glass substrate is heated in the heat treatment step is not less than the strain point Ts (° C.) of the glass substrate and not more than the annealing point Ta (° C.). . If T ₁ (° C.) is higher than the annealing point Ta (° C.) of the glass substrate, the deformation amount of the glass substrate during heat treatment is large, causing large undulations in the glass substrate and hindering the production of flat display panels. . On the other hand, when T ₁ (° C.) is less than the strain point Ts (° C.), the time required for pre-annealing becomes long, and the manufacturing cost increases.
Further, the time t ₁ (h) for holding the glass substrate at T ₁ (° C.) satisfies the following formula.
t ₁ ≧ 10 ^{(1.518logη-20.3 -c / 100)}
In the formula, η is the viscosity (dPa · s) of the glass at the T ₁ (° C.), the viscosity of the glass at the strain point (Ts) is 10 ^14.5 (dPa · s), and at the annealing point (Ta). The viscosity of the glass is 10 ^13.0 (dPa · s) and can be obtained by Arrhenius regression.
C is a target value (acceptable upper limit) (ppm) of compaction generated in the glass substrate during the heat treatment step.
If t ₁ does not satisfy the above equation, it is difficult to reduce the compaction to the target value.
The target value (acceptable upper limit value) of compaction generated in the glass substrate during the heat treatment step varies depending on the type of flat panel display panel, but in the case of an organic EL display panel, it is preferably 50 ppm or less, and 20 ppm or less. It is more preferable that it is 10 ppm or less.

In the manufacturing method of the flat display panel of the present invention, temperature T ₂ (° C.) after raising the temperature of the glass substrate in the pre-annealing step, the time for holding the glass substrate to _{T 2 (℃) t 2 (} h), T When the cooling rate when cooling the glass substrate from ₂ (° C.) to 200 ° C. is r ₂ (° C./min), the pre-annealing step is performed so as to satisfy the following (1) to (3).
T ₂ = T ₁ (1)
r ₂ = r ₁ (2)
t ₂ ≧ t ₁ (3)
R ₁ in the formula (2) is T ₁ during the heat treatment step cooling rate during cooling from (℃) a glass substrate to 200 ℃ (℃ / min). Here, the reason why the cooling rates r ₁ and r ₂ are the cooling rates when cooling from temperatures T ₁ and T ₂ to 200 ° C., respectively, is that 200 ° C. or higher is considered to be a temperature that can affect compaction.
Note that t ₁ and t ₂ are preferably 100 hours or less, more preferably 24 hours or less, further preferably 12 hours or less, and particularly preferably 6 hours or less in consideration of production costs and the like.
Further, the rate of temperature rise of the glass substrate during the pre-annealing step, that is, the rate of temperature rise when raising the temperature of the glass substrate to T ₂ (° C.) is the rate of temperature rise of the glass substrate in the heat treatment step, ie glass Although it is not necessary to coincide with the heating rate when raising the temperature of the substrate to T ₁ (° C.), the difference between the two is preferably within ± 30%, more preferably within ± 10%. It is particularly preferred that the two match.

  In the method for manufacturing a flat display panel according to the present invention, by performing the pre-annealing step and the heat treatment step according to the above-described procedure, the compaction generated in the glass substrate during the heat treatment step can be suppressed to a target value or less.

  In the present invention, the glass constituting the glass substrate is not particularly limited and can be widely selected from those used for flat panel display panels. Specific examples include alkali-containing glass such as soda lime glass, alkali-free glass, and high strain point glass. What is necessary is just to select a suitable material suitably from these materials according to the flat display panel manufactured. For example, when manufacturing an organic EL display panel or an LCD panel, it is preferable to use non-alkali glass from the viewpoint of suppressing deterioration in transistor performance due to alkali diffusion into the TFT semiconductor silicon. When manufacturing PDP, it is preferable to use high-resistance alkali-containing glass or the like from the viewpoints of inhibiting generation of alkali products at the plasma generation electrode and preventing breakdown of interelectrode insulation.

The glass substrate of the present invention is obtained by heating and melting a glass raw material in molten glass, forming the molten glass into a plate glass, slowly cooling it, and then cutting it into a predetermined dimension. The method for forming and slow cooling the plate glass is not particularly limited as long as it is a normal method. For example, it can be obtained by forming into a sheet glass by the float method and gradually cooling, or by forming into a sheet glass by the down draw method and gradually cooling.
The size of the glass substrate is appropriately selected according to the flat display panel to be manufactured. However, even if the shrinkage rate is the same, the absolute value of the shrinkage amount is proportional to the substrate size. . In the case of an organic EL display panel, one side is preferably 700 mm or more, more preferably 900 mm or more, and further preferably 1100 mm or more.

In the method for manufacturing a flat display panel according to the present invention, in addition to the pre-annealing step and the heat treatment step described above, other steps necessary for manufacturing the flat display panel are performed. Such other steps are performed according to the type of flat display panel to be manufactured, but are not particularly limited in the present invention.
Examples of processes required for manufacturing an organic EL display panel include an amorphous silicon formation process, a crystallization (polysiliconization) process, a gate insulating film formation process, a gate line metal formation process, an ion implantation process, and activation. Examples include an annealing process, an interlayer film forming process, a signal line metal forming process, a passivation film forming process, an organic planarizing film forming process, and a transparent pixel electrode forming process. Here, the activation annealing step corresponds to the heat treatment step in the present invention because a plurality of heat treatments are performed at a relatively high temperature.

The present invention will be further described below using examples.
In the embodiment, assuming the heat treatment step when manufacturing the organic EL display panel, the pre-annealing step and the heat treatment step are performed under the following conditions. As the glass substrate, a plate glass having dimensions of 100 mm × 20 mm × 0.7 mm, which is annealed after float forming with non-alkali glass having a strain point (Ts) of 670 ° C. and a slow cooling point (Ta) of 725 ° C. .
Example 1
The pre-annealing process conditions are set assuming that the heat treatment process is performed under the following conditions.
Temperature T ₁ of the temperature was raised heat treatment <br/> glass substrate: 700 ° C.
The cooling rate r ₁ when cooling the glass substrate from T ₁ (° C.) to 200 ° C .: 100 ° C./min The viscosity η of the glass at 700 ° C. is 10 ^13.66 (dPa · s), so the target value c of the compaction is In the case of 10 ppm, since 10 ^{(1.518 log η-20.3 −c / 100)} = 2.17 hours, the time t ₁ for holding the glass substrate at T ₁ (° C.) is set to 2.5 hours.
Pre-annealing step Temperature T ₂ after the glass substrate is heated: 700 ° C.
t ₂ (Time for holding the glass substrate at T ₂ (° C.)): 2.5 hours The cooling rate when cooling the glass substrate to 200 ° C. from T ₂ (° C.) is r ₂ : 100 ° C./min. A pre-annealing step and a heat treatment step are performed.
The compaction generated during the heat treatment process is calculated according to the following procedure.
After pre-annealing, two indentations are made on the surface of the glass substrate in the long side direction at intervals A (A = about 90 mm). Next, the distance between the indentations after the heat treatment step is measured, and the distance is B. The compaction (c) is obtained from A and B thus obtained using the following equation. A and B are measured using an optical microscope capable of measuring length.
c [ppm] = (A−B) / A × 10 ⁶
The compaction obtained by the above procedure is 10 ppm or less, which satisfies the target value.

(Example 2)
The pre-annealing step and the heat treatment step are performed under the following conditions.
Heat treatment step T ₁ : 710 ° C.
r ₁ : 100 ° C./min Since the viscosity η of the glass at 710 ° C. is 10 ^13.39 (dPa · s), when the target value c of the compaction is 10 ppm, 10 ^{(1.518 log η−20.3 −c / 100)} = 0 Since it is 84 hours, t _{1 is set} to 1 hour.
Pre-annealing step T ₂ : 710 ° C.
t ₂ : 1 hour r ₂ : 100 ° C./min The compaction generated in the glass substrate during the heat treatment step is obtained in the same procedure as in Example 1. Compaction is 10 ppm or less, which satisfies the target value.

(Example 3)
The pre-annealing step and the heat treatment step are performed under the following conditions.
Heat treatment step T ₁ : 720 ° C.
r ₁ : 100 ° C./min Since the viscosity η of the glass at 720 ° C. is 10 ^13.13 (dPa · s), when the target value c of the compaction is 10 ppm, 10 ^{(1.518 log η−20.3 −c / 100)} = 0 Since t is 34 hours, t _{1 is set} to 0.5 hours.
Pre-annealing step T ₂ : 720 ° C.
t ₂ : 1 hour r ₂ : 100 ° C./min The compaction generated in the glass substrate during the heat treatment step is obtained in the same procedure as in Example 1. Compaction is 10 ppm or less, which satisfies the target value.

Example 4
The pre-annealing step and the heat treatment step are performed under the following conditions.
Heat treatment step T ₁ : 690 ° C.
r ₁ : 100 ° C./min Since the viscosity η of the glass at 690 ° C. is 10 ^13.93 (dPa · s), when the target value c of the compaction is 50 ppm, 10 ^{(1.518 log η−20.3 −c / 100)} = 2 Since it is 22 hours, t ₁ is 3 hours.
Pre-annealing step T ₂ : 690 ° C.
t ₂ : 3 hours r ₂ : 100 ° C./min The compaction generated in the glass substrate during the heat treatment step is obtained in the same procedure as in Example 1. Compaction is 50 ppm or less, which satisfies the target value.

(Example 5)
The pre-annealing step and the heat treatment step are performed under the following conditions.
Heat treatment step T ₁ : 700 ° C.
r ₁ : 100 ° C./min Since the viscosity η of the glass at 700 ° C. is 10 ^{13. 66} (dPa · s), when the compaction target value c is 50 ppm, 10 ^{(1.518 log η−20.3 −c / 100)} = 0.86 hours, so t ₁ is 1 hour.
Pre-annealing process T ₂ : 700 ° C
t ₂ : 1 hour r ₂ : 100 ° C./min The compaction generated in the glass substrate during the heat treatment step is obtained in the same procedure as in Example 1. Compaction is 50 ppm or less, which satisfies the target value.

(Example 6)
The pre-annealing step and the heat treatment step are performed under the following conditions.
Heat treatment step T ₁ : 720 ° C.
r ₁ : 100 ° C./min Since the viscosity η of the glass at 710 ° C. is 10 ^13.39 (dPa · s), when the target value c of the compaction is 50 ppm, 10 ^{(1.518 log η−20.3 −c / 100)} = 0 Since t is 335 hours, t _{1 is set} to 0.5 hours.
Pre-annealing step T ₂ : 720 ° C.
t ₂ : 1 hour r ₂ : 100 ° C./min The compaction generated in the glass substrate during the heat treatment step is obtained in the same procedure as in Example 1. Compaction is 50 ppm or less, which satisfies the target value.

Claims (4)

A step of pre-annealing a glass substrate, and a heat treatment step performed for the purpose of forming a display element on the glass substrate, and a method for producing a flat display panel,
The flat display panel is an organic electroluminescence (EL) display panel, and the heat treatment performed for the purpose of forming a display element on the glass substrate is a heat treatment performed for the purpose of crystallizing the deposited silicon. And
The temperature after raising the temperature of the glass substrate in the heat treatment step is T ₁ (° C.) (where T ₁ is not less than the strain point Ts (° C.) of the glass substrate and not more than the annealing point Ta (° C.) , and 600 to 800 ° C. ), and the time for holding the glass substrate at T ₁ (° C.) is t ₁ (h) (where t ₁ ≧ 10 ^{(1.518 log η−20.3 −c / 100)} , where η is the T ₁ Viscosity (dPa · s) of the glass at (° C.), c is a target value (acceptable upper limit value) (ppm) of compaction generated in the glass substrate during the heat treatment step, and T ₁ (° C.) The cooling rate when cooling the glass substrate to 200 ° C. from r ₁ (° C./min),
The temperature after raising the temperature of the glass substrate in the pre-annealing step is T ₂ (° C.), the time for holding the glass substrate at T ₂ (° C.) is t ₂ (h), and the glass from the T ₂ (° C.) When the cooling rate when cooling the substrate to 200 ° C. is r ₂ (° C./min),
The method for producing a flat display panel, wherein the pre-annealing step is performed so as to satisfy the following (1) to (3).
T ₂ = T ₁ (1)
r ₂ = r ₁ (2)
t ₂ ≧ t ₁ (3) A step of pre-annealing a glass substrate, and a heat treatment step performed for the purpose of forming a display element on the glass substrate, and a method for producing a flat display panel,
The flat display panel is a plasma display panel (PDP), and the heat treatment step performed for the purpose of forming a display element on the glass substrate is a heat treatment performed for the purpose of forming a plasma light emitting cell,
The temperature after the temperature rise of the glass substrate in the heat treatment step is T ₁ (℃) (However, T ₁ Is a strain point Ts (° C.) or more and an annealing point Ta (° C.) or less and 450 to 650 ° C. of the glass substrate). ₁ (T) is the time to hold ₁ (H) (however, t ₁  ≧ 10 ^{(1.518logη-20.3 -c / 100)} . Where η is the T ₁ The viscosity (dPa · s) of the glass at (° C.), c is a target value (acceptable upper limit) (ppm) of compaction generated in the glass substrate during the heat treatment step. ), T ₁ The cooling rate when cooling the glass substrate to 200 ° C. from (° C.) r ₁ (° C / min)
The temperature after the temperature rise of the glass substrate in the pre-annealing step is T ₂ (° C.), the glass substrate is ₂ (T) is the time to hold ₂ (H) the T ₂ The cooling rate when cooling the glass substrate to 200 ° C. from (° C.) r ₂ (C / min)
The method for producing a flat display panel, wherein the pre-annealing step is performed so as to satisfy the following (1) to (3).
T ₂  = T ₁   (1)
r ₂  = R ₁   (2)
t ₂  ≧ t ₁   (3) The flat display panel manufacturing method according to claim 1, wherein a target value (allowable upper limit value) c of the compaction is 50 ppm.   The method for producing a flat display panel according to claim 1, wherein the glass substrate is an alkali-free glass substrate.