JPH06186549A - Heating method and heating furnace for substrate - Google Patents

Abstract

PURPOSE:To provide the heating furnace capable of preventing the adhesion of microdust on the surface of a glass substrate. CONSTITUTION:Previously heated gas is supplied atop the glass substrate G consisting of gas supply holes 25 to maintain the gaseous pressure between a punching plate 26 and the glass substrate G at the gaseous pressure higher than in a space where a glass substrate transporting mechanism 15 exists. The gas flows from the gas supply cylindrical part 23 of a hood 21 via the gas supply holes 25 atop the glass substrate G and flows from the spacing between the glass substrate G and the lower edge 22 to the space where the glass substrate transporting mechanism 15 exists. The microdust does not flow to the glass substrate G side and is discharged from a discharge port 14 even if the microdust splashes from a beam holding mechanism 18 or the ambient. The microdust generated from the glass substrate transporting mechanism 15 is pushed back by the flowing out gaseous flow even if the dust soars up and, therefore, the infiltration of the dust to the upper part of the glass substrate G is not possible. The adhesion of the microdust to the surface of the glass substrate G does not arise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, evaporates a solvent of an alignment film on a glass substrate in a manufacturing process of a liquid crystal display device,
The present invention relates to a method for heating a substrate to be dried and a heating furnace.

[0002]

2. Description of the Related Art Generally, the manufacturing process of a liquid crystal display device is
There is a drying step in which an alignment film on a liquid is printed on the surface of a glass substrate, a solvent is evaporated by heating, and a film is formed.

In this drying step, since it is necessary to heat the glass substrate more uniformly in order to avoid unevenness of the dried state of the film and to continuously process the glass substrate on the production line, several sheets are arranged in the furnace body. Further, the glass substrate is continuously moved on the heating plate to gradually heat the glass substrate, which is a single-wafer type. Also, in order to prevent dust from adhering to the surface of the glass substrate and uneven dryness, it is necessary to constantly perform purging and exhausting with a clean gas to keep the atmosphere temperature in the furnace stable and dust-free. .

That is, the surface of the glass substrate is a transparent electrode provided at intervals of several microns, and the thickness of the alignment film is an angstrom unit, which is a very fine structure.

Therefore, if even a small amount of dust of about several microns adheres to the surface, it will appear as spots during display, and defects such as short circuits between electrodes will occur. If dust adheres in this process, it will adhere to the film on the liquid and once heated,
It adheres to the glass substrate together with the film and cannot be recovered and reused later.

Therefore, here, it is required that even a small amount of fine dust can be deposited without adhering to the surface of the glass substrate.

The structure of the conventional heating furnace is shown in FIG.
And shown in FIG.

In FIGS. 2 and 3, reference numeral 11 denotes a furnace body, which has a dust-free interior, has an inlet 12 and an outlet 13 at one end and the other end in the longitudinal direction, and has a lower part at the bottom. The exhaust port 14 is formed. Further, a glass substrate transfer mechanism 15 for transferring the glass substrate G to be heated is disposed between the inlet 12 and the outlet 13, and the glass substrate transfer mechanism 15 is provided.
A plurality of heating plates 16 for heating the glass substrate G are arranged between them along the conveyance direction of the glass substrate G.

The glass substrate carrying mechanism 15 has a carrying beam 17, which is arranged on both sides of the heating plate 16 in correspondence with the heating plate 16 and operates synchronously with each other to move up and down. By moving forward and backward, the glass substrate G is sequentially conveyed to the next heating plate 16. In addition,
Since the carrier beam 17 extends long from the inlet 12 to the outlet 13 in the furnace body 11, it is necessary to hold the carrier beam 17, and the carrier beam 17 that holds the carrier beam 17 in a key portion in the furnace body 11 is held. The mechanism 18 is provided. Also, the beam holding mechanism 18
The portion directly receiving the carrier beam 17 is a bearing 19, and this bearing 19 holds the carrier beam 17 and suppresses the friction of the surface that directly contacts when the carrier beam 17 moves forward and backward.

Further, the inside of the furnace body 11 is purged with clean gas from the outlet 13 toward the inlet 12 by the purge nozzle 20.

Next, the operation of the above conventional example will be described.

First, the carrying beam 17 rises to pick up the glass substrate G and carry it at a constant distance from the heating plate 16 toward the next heating plate 16 at a constant speed. Then, the carrier beam 17 is heated by the glass plate G on the next heating plate 16
When stopped, the carrier beam 17 descends to place the glass substrate G on the heating plate 16. Further, the carrier beam 17 that has descended completely retreats to the position where it started to move forward and then stops.

By repeating this series of operations, the glass substrate G is sequentially transported.

The inside of the furnace body 11 is purged with clean gas from the outlet 13 toward the inlet 12 by the purge nozzle 20, and is constantly exhausted through the exhaust port 14, so that the atmosphere temperature inside the furnace body 11 is always stable and stable. It is kept in a dusty state.

Then, the glass substrate G is sequentially moved from the heating plate 16 to the next heating plate 16 by the glass substrate transfer mechanism 15 in the furnace body 11.

[0016]

As described above, the purge nozzle 20 and the exhaust port 14 always keep the atmosphere in the furnace body 11 in a dust-free state, but the beam holding mechanism arranged in the furnace body 11 is used. Minute dust is generated from the contact surface of the bearing 19 of the bearing 18 with the carrier beam 17, the rotation axis, the surroundings, etc. Then, although it should have been exhausted from the exhaust port 14 at the same time as the exhaust in the atmosphere, due to the effect of the gas purge from the purge nozzle 20, on the contrary, it rises up on the glass substrate G and the glass It has a problem that it adheres to the surface of the substrate G.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate heating method and a heating furnace capable of preventing minute dust from adhering to the surface of a glass substrate. .

[0018]

According to the method for heating a substrate of claim 1, the substrate is transferred in a closed furnace, and the transferred substrate is heated in the furnace. The heated gas is supplied to the upper surface of the substrate in the furnace to heat the upper surface of the substrate with the atmospheric pressure higher than the ambient temperature.

According to the second aspect of the present invention, in the heating device, the substrate is transported by the substrate transport mechanism in the sealed furnace body, and the substrate transported by the substrate transport mechanism is heated by the heating means. A substrate having a gas supply hole for supplying gas toward the upper surface of the substrate and a gas supply mechanism for supplying preheated gas into the hood; The air pressure between the upper surface of the hood and the hood is higher than the surrounding area.

[0020]

According to the first aspect of the present invention, there is provided a method for heating a substrate, wherein the substrate is transferred into a hermetically sealed furnace body, the transferred substrate is heated in the furnace body, and the gas heated on the upper surface of the substrate is heated in the furnace body. Since it is supplied and heated with the atmospheric pressure of the upper surface higher than the surroundings, the atmospheric pressure of the atmosphere on the upper surface of the substrate is always maintained at a higher atmospheric pressure than the surroundings, and since minute dust does not enter the upper part of the substrate, No dust adheres to the substrate.

In the heating furnace according to the second aspect of the present invention, the substrate is transferred by the substrate transfer mechanism into the closed furnace, the substrate transferred by the substrate transfer mechanism is heated by the heating means, and the hood is directed toward the upper surface of the substrate. Since the preheated gas is supplied from the gas supply hole of, the atmospheric pressure of the atmosphere surrounded by the upper part of the substrate and the hood is always kept higher than the ambient pressure, and the heated gas from between the substrate and the hood is It will always flow out, and the minute dust generated from the substrate transfer mechanism will not enter the atmosphere surrounded by the upper part of the substrate and the hood.
No dust adheres to the substrate.

[0022]

EXAMPLES An example of the present invention will be described below with reference to the heating furnace shown in FIG. The parts corresponding to those of the conventional example shown in FIGS. 2 and 3 are designated by the same reference numerals for description.

As in the case shown in FIG. 2, the dust-free furnace body 11 has an inlet 12 and an outlet 13 at one end and the other end in the longitudinal direction.
And an exhaust port 14 is formed in the lower part. Further, a glass substrate transfer mechanism 15 for transferring the glass substrate G to be heated is arranged between the inlet 12 and the outlet 13, and a heating plate as a heating means for heating the glass substrate G between the glass substrate transfer mechanisms 15. 16 is the glass substrate G
A plurality of sheets are arranged along the conveyance direction of.

The glass substrate carrying mechanism 15 has a carrying beam 17, which is arranged on both sides of the heating plate 16 in correspondence with the heating plate 16 and operates synchronously with each other and moves up and down. By moving forward and backward, the glass substrate G is sequentially conveyed to the next heating plate 16. In addition,
Since the carrier beam 17 extends long from the inlet 12 to the outlet 13 in the furnace body 11, it is necessary to hold the carrier beam 17, and the carrier beam 17 that holds the carrier beam 17 in a key portion in the furnace body 11 is held. The mechanism 18 is provided. Also, the beam holding mechanism 18
The portion directly receiving the carrier beam 17 is a bearing 19, and this bearing 19 holds the carrier beam 17 and suppresses the friction of the surface that directly contacts when the carrier beam 17 moves forward and backward.

Further, a hood 21 is provided above the heating plate 16 so as to surround the glass substrate G, and the hood 21 is provided on both sides of the glass substrate G in the carrying direction with a gap therebetween. Lower edges along both sides of the transport mechanism 15
22 are formed. In addition, the hood 21 is a gas supply tube portion 23.
A nozzle 24 as a gas supply mechanism for supplying preheated gas is formed in the gas supply cylinder portion 23. Further, on the lower surface of the hood 21, there is provided a punching plate 26 having a large number of fine gas supply holes 25 for supplying gas from the gas supply cylinder portion 23.

Next, the operation of the above embodiment will be described.

First, the carrying beam 17 rises to pick up the glass substrate G and carry it at a constant distance from the heating plate 16 toward the next heating plate 16 at a constant height. Then, the carrier beam 17 is heated by the glass plate G on the next heating plate 16
When stopped, the carrier beam 17 descends to place the glass substrate G on the heating plate 16. Further, the carrier beam 17 that has descended completely retreats to the position where it started to move forward and then stops.

By repeating this series of operations, the glass substrate G is sequentially transported.

Further, the dust-free clean heated gas supplied from the nozzle 24 is evenly supplied to the hood 21.
The air pressure of the gas supply tube portion 23 in the inside is increased, and the preheated gas is supplied from the gas supply hole 25 to the upper surface of the glass substrate G to punch the punching plate 26 of the hood 21 and the glass substrate G.
The atmospheric pressure in the space between and is made higher than that in the space where the glass substrate transport mechanism 15 and the like are located.

Then, the glass substrate G is sequentially moved from the heating plate 16 to the next heating plate 16 by the glass substrate transfer mechanism 15 in the furnace body 11.

As described above, the preheated gas is supplied to the upper surface of the glass substrate G from the gas supply hole 25, and the atmospheric pressure of the space between the punching plate 26 of the hood 21 and the glass substrate G is transferred to the glass substrate. By making the pressure higher than the space where the mechanism 15 and the like are located, the gas flow flows from the gas supply cylinder portion 23 of the hood 21 to the upper surface of the glass substrate G through the gas supply holes 25, and the glass substrate G and the lower edge. Since it flows from the gap of the portion 22 to the space where the glass substrate transport mechanism 15 is located, for example, minute dust is scattered from the contact surface of the bearing 19 of the beam holding mechanism 18 with the transport beam 17, the rotating shaft or the surroundings. However, the gas is exhausted through the exhaust port 14 without flowing to the glass substrate G side. For this reason, the minute dust generated from the sliding portion of the glass substrate transport mechanism 15 is pushed back by the flowing airflow even when it rises, and cannot enter the upper portion of the glass substrate G.

Therefore, minute dust is generated on the glass substrate G.
It will not adhere to the surface of.

[0033]

According to the substrate heating method of the first aspect of the present invention, the substrate is transferred into a hermetically sealed furnace body, the transferred substrate is heated in the furnace body, and the upper surface of the substrate is heated in the furnace body. The atmospheric pressure of the atmosphere on the upper surface of the substrate is always kept higher than that of the surroundings by supplying the generated gas to heat the upper surface at a pressure higher than that of the surroundings. Since it does not enter, dust does not adhere to the substrate.

According to the heating furnace of the second aspect, the substrate is carried by the substrate carrying mechanism into the closed furnace body, and the substrate carried by the substrate carrying mechanism is heated by the heating means to face the upper surface of the substrate. Since the preheated gas is supplied from the gas supply hole of the hood, the atmospheric pressure of the atmosphere surrounded by the upper part of the substrate and the hood is always kept higher than the atmospheric pressure of the surroundings, and the space between the substrate and the hood is heated. The gas always flows out, and the minute dust generated from the substrate transfer mechanism does not enter the atmosphere surrounded by the upper portion of the substrate and the hood, so that the dust does not adhere to the substrate.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the inside of a furnace showing an embodiment of a heating furnace of the present invention.

FIG. 2 is an explanatory view showing a furnace body of a conventional heating furnace.

FIG. 3 is an explanatory view showing the inside of the heating furnace of the same heating furnace.

[Explanation of symbols]

 11 furnace body 15 glass substrate transfer mechanism 16 heating plate as heating means 21 hood 24 nozzle as gas supply mechanism 25 gas supply hole G glass substrate

Claims (2)

[Claims] 1. A heating method for transporting a substrate in a hermetically sealed furnace body and heating the transported substrate in the furnace body, wherein heated gas is supplied to the upper surface of the substrate in the furnace body. A method for heating a substrate, characterized in that the substrate is heated while the atmospheric pressure on the upper surface of the substrate is higher than the ambient pressure. 2. A heating device in which a substrate is transported by a substrate transport mechanism in a hermetically sealed furnace body, and the substrate transported by the substrate transport mechanism is heated by a heating means. The heating device is provided above the transported substrate. A hood having gas supply holes for supplying gas toward the upper surface of the substrate, and a gas supply mechanism for supplying preheated gas into the hood are provided, and the air pressure between the upper surface of the substrate and the hood is provided. The heating furnace is characterized in that the height is higher than the surrounding area.