JP3299882B2 - heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace for heating a substrate in a process of manufacturing a substrate for a liquid crystal display or a substrate for a plasma display.

[0002]

2. Description of the Related Art Recently, liquid crystal and plasma display panels have been widely used for displays because of their light weight, thin shape, and low power consumption. In the manufacturing process of such a panel, taking a liquid crystal display panel (hereinafter referred to as a liquid crystal panel) as an example,
There is a step of heating and curing a sealant applied on a glass substrate for a liquid crystal panel. As a heating means, conventionally, a glass substrate is placed on a hot plate and sealed at a desired temperature. A hot plate type heating furnace for heating the agent is used.

FIG. 8 is a longitudinal sectional view showing a schematic structure of an example of such a conventional heating furnace described in JP-A-2-83230, and FIG. 9 is a sectional view taken along the line EE in FIG. 40 is a heating furnace loading section, 41 is a furnace body, 42 is a heating furnace discharge section, 43 is a substrate transfer mechanism, 44 is a furnace body case,
45 is a motor, 46 is a ball screw, 47 is a nut, 48
Is a linear guide, 49 is a lateral moving mechanism, 50 is a motor, 5
1 is a ball screw, 52 is a nut, 53 is a linear guide,
54 is a cam, 55 is a guide, 56 is a vertical movement mechanism, 57 is a board moving plate, 58 is a gantry frame, 59 is a board, 60a
60c is a hot plate (hereinafter, when a specific hot plate is indicated, a lowercase letter 6 is added to the end of the code).
0a, 60b, and 60c, which are collectively referred to as a hot plate 60), 61 is a column, and 62 is an exhaust pipe.

In FIG. 8, a substrate 59 to which a sealant has been applied in a previous step is loaded into a loading section 40 before being loaded into a heating furnace.
Is held. Inside the furnace body 41, hot plates 60a to 60c for mounting and heating the substrate 59 are provided. Substrate 5 for which heat curing treatment of sealant has been completed
9 is conveyed to the carry-out part 42 of the heating furnace, from which it is carried out to the device in the next step.

In the furnace body 41, a substrate transport mechanism 43 for transporting a substrate 59 from the loading section 40 to the unloading section 42 is provided.
Are provided below the hot plate 60, and the hot plate 60 and the substrate transfer mechanism 43 are covered with a furnace case 44. An exhaust pipe 62 for discharging gas generated inside the furnace case 44 is provided at the ceiling of the furnace case 44.

The hot plate 60 is supported by a column 61, and the furnace case 44 and the column 61 are fixed to a gantry frame 58 at the lower part of the apparatus. The substrate transport mechanism 43 includes a motor 45, a ball screw 46, a nut 47, and a linear guide 48.
A horizontal moving mechanism 49 comprising a motor 50, a ball screw 51, a nut 52, a linear guide 53, a cam 54, a guide 55, etc .;
4 and a substrate moving plate 57 extending from the carry-in portion 40 to the carry-out portion 42.

A horizontal moving mechanism 49 for driving the substrate moving plate 57
Converts the rotation of the motor 45 into a linear movement by means of the ball screw 46 and the nut 47, and drives the substrate moving plate 57 on the linear guide 48 in the horizontal direction in FIG. The distance that the lateral moving mechanism 49 drives the substrate moving plate 57 is determined by the hot play.
G is equal to the center-to-center distance of the points 60a to 60c.

The vertical movement mechanism 56 converts the rotation of the motor 50 into a linear movement by means of the ball screw 51 and the nut 52, and drives the cam 54 on the linear guide 53, so that it is on the cam 54. The guide 55 is driven up and down, whereby the substrate moving plate 57 is driven up and down in FIG.

Each of the motors 45 and 50 has a built-in encoder, and is further connected to a controller (not shown), and sends a signal to the controller when it rotates in a predetermined direction by a predetermined amount. The controller controls the stop, normal rotation, reverse rotation, and the like of the motors 45 and 50 according to this signal.

The sealant applied to the substrate 59 has a specific critical temperature at which the curing progresses rapidly and the physical properties change. When the critical temperature is exceeded, the sealant rapidly cures. Therefore, if the temperature and time for heating beyond the critical temperature are not uniform over the entire surface of the substrate 59, the curing of the sealant will be uneven, and properties such as hardness and adhesiveness will be non-uniform, and the substrate 59 will not be uniform.
The quality will be reduced.

Further, when the substrate 59 is rapidly heated, the temperature difference on the surface of the substrate 59 increases until the temperature of the substrate 59 rises and stabilizes, which causes unevenness in the properties of the sealant. In some cases, the stress may be increased to cause breakage. Therefore, the substrate 59 is once preheated at a temperature lower than the critical temperature at which the sealant is hardly cured. Therefore, in general, the temperature of the hot plate 60 is increased step by step in the arrangement order of the hot plates 60 from the loading unit 40 side in order to enable the preheating.

Conventionally, the temperature, time, and the like for performing necessary heating are secured, and the substrate 59 is provided at intervals required by the production line.
In order to supply the hot plate 60, the temperature and quantity of the hot plate 60 are preliminarily increased in a stepwise manner from the loading side, under conditions such as a temperature and a holding time determined by an interval for transporting the substrate 59. The portion to be heated at a desired temperature equal to or higher than the critical temperature is determined according to conditions such as a holding time determined by a holding temperature and an interval at which the substrate 59 is transported.

In the conventional heating furnace shown in FIGS. 8 and 9, the hot plate 60a is a portion for performing preheating, and the temperature is lower than the critical temperature. Also, the hot plates 60b, 6
0c is a portion for heating (main heating) at a desired temperature above the critical point, and the temperature is maintained at the same desired temperature above the critical temperature.

Next, the operation of the heating furnace having such a structure for heating and curing the sealant applied to the substrate 59 will be described.

First, when the substrate 59 is placed on the carry-in portion 40, the motor 50 rotates to move the cam 54 toward the carry-in portion 40, and at the same time, the guide 55 moves upward to move the substrate moving plate 57. Lift. In this process, the substrate moving plate 57 puts the substrate 59 mounted on the loading unit 40 and raises the substrate 59, thereby separating the substrate 59 from the loading unit 40. When the substrate moving plate 57 is lifted to a predetermined height, the motor 5
0 stops and is held at that height.

Next, the motor 45 rotates and the substrate moving plate 5
7 is moved to the unloading section 42 side. Then, the substrate moving plate 5
When the substrate 59 placed on 7 is transported above the hot plate 60a, the motor 45 stops. In this state, the motor 50 rotates in the opposite direction to the above,
4 is moved to the unloading section 42 side, and the substrate moving plate 57 is lowered from the surface of the hot plate 60 and stopped. Thus, the substrate 59 is mounted on the hot plate 60a.

Thereafter, the motor 45 rotates in the direction opposite to the above, and at the same time, the substrate moving plate 57 is
Move to the side. Then, when the substrate moving plate 57 returns to the original position, the motor 45 stops, and one operation ends.

When the first operation is completed, after a lapse of a predetermined time during which preheating is performed, the substrate moving plate 57 repeats the above operation again, and the second operation of moving the substrate 59 from the hot plate 60a to the hot plate 60b is performed. Done
Next, in the third operation, the substrate 59 is placed on the hot plate 60.
b from the hot plate 60c to the hot plate 60c.
To be carried out.

[0019]

However, the conventional heating furnace has the following problems.

Since the upper surface of the substrate 59 is coated with a sealant, the lower surface is supported by the substrate moving plate 57 during transport. Therefore, the hot plate 60
As shown in FIG. 9, is provided to mount a portion of the substrate 59 other than the portion supported by the substrate moving plate 57.

Further, in order to correspond to the substrates 59 having different dimensions, substrate moving plates 57 for supporting the substrates 59 are provided movably on both sides of the substrate 59 in the feeding direction. If the width dimension in the direction perpendicular to the feed direction is limited and the substrate 59 becomes large,
The area of the portion of the substrate 59 protruding from above the hot plate 60 is increased. However, the temperature of the protruding peripheral edge of the substrate 59 is unlikely to rise, and further, during the movement of the substrate 59, heat is taken by the substrate moving plate 57 due to contact with the substrate moving plate 57 supporting the substrate 59, Hot plate 60
The temperature drops as you move away from the surface. Since the furnace body case 44 accommodates a plurality of hot plates 60, substrate moving plates 57, and operating parts thereof having different heating temperatures, the furnace body case 44 has a large volume and a large height. Convection occurs throughout 44. The convection is likely to be disturbed by the vertical and horizontal movements of the substrate moving plate 57, whereby the surface temperature of the substrate 59 moving between the hot plates 60 is not constant, and the curing of the sealant becomes uneven.

Further, when the substrate 59 is enlarged and thickened, a temperature difference occurs between the upper and lower surfaces of the substrate 59 when the substrate 59 is heated while being placed on the hot plate 60, so that the substrate 59 warps on the hot plate 60. Thus, a problem that uniform heating could not be achieved was also confirmed.

Further, the substrate 59 is repeatedly moved between the hot plates 60, so that the substrate 59 and the substrate moving plate 5 are moved.
Since the number of times of contact with the hot plate 7 and the hot plate 60 increases, the amount of dust generated increases. It is desirable that the moving time between the hot plates 60 be short in order to prevent the temperature of the substrate 59 from lowering. However, when the substrate 59 is moved between the hot plates 60 at a high speed, The air flow inside the furnace body 41 is greatly disturbed, and the dust rises, further reducing the cleanliness. In addition, since the driving unit of the substrate moving plate 57 is located inside the furnace case 44, which is the same as the hot plate 60, and the outside air enters by convection, the cleanliness is reduced. From the above, the quality of the substrate 59 is reduced due to the adhesion of the dust to the substrate 59.

Further, in order to secure an amount of supplying the substrate 59 after the sealing agent has been heated and hardened by giving a desired heating time to a downstream device connected to the heating furnace, the furnace body becomes long and large. An installation area is required. In particular, since the manufacturing apparatus for the substrate 59 is often installed on a clean room,
The installation area becomes a problem.

A similar problem is found in firing conductive paste and the like on a printed circuit board.

An object of the present invention is to solve such a problem, and to uniformly heat and cure a sealant or a paste applied to the surface of a substrate surface, so that a high-quality substrate can be obtained. To provide a small heating furnace.

[0027]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of small holes penetrating a heating plate, and a plurality of small diameter rods penetrating the small holes. A holding means for the substrate provided so as to be able to protrude, an elevating means for elevating and lowering the holding means for the substrate, and a length of the holding means for the substrate protruding above the heating plate are controlled to perform preheating, main heating and cooling. Means for controlling the temperature to each temperature, and a container that includes the holding means for the heating plate and the substrate, shields the outside air, and at least the inner surface facing the upper surface of the heating plate has a mirror surface. An opening is provided for horizontally moving the substrate and mounting the substrate on the holding means for the substrate in the container.

With this configuration, since the holding means for the substrate is provided in the form of a plurality of small-diameter rods and penetrates the inside of the heating plate, the area of the heating plate can be made large and the entire substrate surface can be in close contact with the surface of the heating plate. And the entire substrate surface can be evenly heated by heat conduction.

Further, since preheating, main heating and cooling can be performed only on the upper and lower sides of the substrate on one heating plate, the total volume and the total height in the container can be suppressed. Therefore, the temperature in the container is made uniform and the temperature difference is reduced, so that convection is less generated and the heating temperature is stabilized. Since the holding means of the substrate has a small contact area with the substrate, the generation of dust due to friction is small, and the mounting of the substrate on the heating plate is carried out from a preheating position close to the heating plate, so that the periphery of the heating plate at the time of mounting is mounted. Since the turbulence of the air flow can be reduced and the convection in the container is suppressed, the dust is not sowed up, so that a decrease in cleanliness can be prevented.

Further, when far infrared rays emitted from the heating plate once pass through a glass substrate, they are partially absorbed by the substrate and members provided on the upper surface thereof, and the far infrared rays transmitted through the substrate are reflected by the inner surface of the container. The light is reflected to reach the upper surface of the substrate, is absorbed by members provided on the upper surface of the substrate, and these members are warmed, transmitted to the upper surface of the substrate, and the upper surface is also heated. As a result, the temperature difference between the upper and lower surfaces of the substrate is reduced, and uniform heating is possible with almost no warpage of the substrate. Further, at this time, the far-infrared ray reflected on the inner surface of the container and passed through the glass substrate returns to the heating plate and heats the heating plate itself. Thereby, the heating energy of the heating plate itself can be reduced by that much, which is also effective in terms of energy saving. And the opening of the container and the lifting hand
Open and close according to the elevation of the elevating means, respectively at the elevator of the step
A shielding plate was provided. For this reason, during heating of the substrate,
Cold air containing dust does not flow in and uniform temperature
Heating and high cleanliness can be obtained.

[0031]

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

FIGS. 1 to 5 show a basic structure of a heating furnace according to the present invention .
FIG. 1 is a front view showing the external appearance, wherein 1 is a gantry frame, 2 is a furnace body, 3 is a control unit, 4 is a partition base plate, 5 is a column, 6 is a frame, 8 Is a partition, and 9 is an opening.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, wherein 10 is a door (inspection door), 11 is lifting means, 12 is a substrate, 13 is an exhaust pipe, and 14 is a transfer robot. , FIG.
Are assigned the same reference numerals.

FIG. 3 is a sectional view of a main part taken along the line BB in FIG. 1, wherein 15 is a lifting pin, 16 is a hot plate,
17 is a column, 18 is a heat dissipation prevention cover, 19 is a displacement prevention pin, 20 is a vacuum suction hole, 21 is a vacuum pipe, 22 is a heating heater, 23 is an air supply pipe, 24 is a vertical drive plate, and 25 is a horizontal drive plate. It is a frame, and portions corresponding to the above-mentioned drawings are denoted by the same reference numerals.

FIG. 4 is a cross-sectional view of a main part taken along section line CC of FIG. 2, and portions corresponding to the above-mentioned drawings are denoted by the same reference numerals.

In FIGS. 1 and 2, the heating furnace is installed on the floor by a gantry frame 1 having legs. The gantry frame 1 has a space I for accommodating a furnace body 2 for heating, and a space for accommodating a controller 3 serving as a means for controlling the temperature of the substrate 12 for elevating and lowering a holding means for the substrate 12 to be described later and a means for controlling the entire heating furnace. It is divided into two upper and lower parts with the part II.

In the upper space portion I of the gantry frame 1, there are provided two sets of frames 6 each composed of a combination of a partition base plate 4 arranged horizontally and a column 5 supported vertically. Are arranged laterally. In one framework 6, the partition base plate 4 on the ceiling side of the upper space portion I
The partition base plate 4 on the bottom surface side and the partition base plate 4 between them are horizontally arranged with each other, and are supported by columns 5 at two locations on both left and right sides. This one framework 6
The furnace body 2 is installed in each of two upper and lower spaces. Accordingly, in the upper space portion I of the gantry frame 1, two furnace bodies 2 are provided, two on the upper side and two on the lower side.

The part of the furnace body 2 to be heated is covered with a container-shaped partition 8, and the bottom of the partition 8 is fixed to the partition base plate 4. As shown in FIG. 2, the partition 8 is provided with an opening 9 for carrying the substrate 12 in and out.
In addition, as shown in FIG. 2, detachable inspection doors 10 are provided on both sides of the container by the partition wall 8. Since the inspection door 10 on one side of the partition 8 is on the outer surface side of the heating furnace, the inspection door 10 can be removed and the furnace body 2 can be maintained.

The substrate 12 is a substrate for a liquid crystal display or a plasma display. For example, a substrate such as glass that can transmit far infrared rays is coated with a sealant in a separate process.

Elevating means 11 are provided for each furnace body 2 and fixed to the partition base plate 4 respectively. The elevating means 11 has a reciprocating mechanism including a drive motor, a ball screw, and the like (not shown), and its operation is controlled by the control unit 3. As shown in FIG. 3, a vertical drive plate 24 driven vertically by the reciprocating mechanism is connected to the lifting / lowering means 11, and the vertical drive plate 24 extends into the furnace body 2.

In the furnace body 2, as shown in FIGS. 3 and 4, a plurality of horizontal frames 25 are connected to a vertical drive plate 24.
The lifting pins 15 are connected to the upper surface of the horizontal frame 25. The elevating pins 15 are rod-shaped with a small diameter, and are holding means for the substrate 12.

A hot plate 16 serving as a heating plate for contacting and heating the substrate 12 is disposed in the furnace body 2, and the hot plate 16 is connected to the partition base plate 4 via a support 17. Fixed.

The partition 8 facing the hot plate 16
, Especially the inner surface (upper inner surface or side inner surface) of the partition wall facing the hot plate 16 is mirror-polished.

A heat radiation preventing cover 18 is provided outside the hot plate 16. The heat radiation prevention cover 18 is made of a metal plate such as stainless steel.
Slightly away from it to cover it. As a result, an air layer is formed between the hot plate 16 and the heat dissipation prevention cover 18, and the air layer forms the hot plate 1.
6, the amount of heat radiation is suppressed, and the temperature of the hot plate 16 is stabilized. The hot plate 16 and the heat radiation preventing cover 18 are provided with small holes penetrating them vertically.

The substrate 12 is mounted on a plurality of elevating pins 15 arranged above the hot plate 16. The elevating pins 15 are provided in an appropriate arrangement so as to correspond to the shapes of all the target substrates 12, and their lengths protruding from the hot plate 16 surface are made equal to each other. Further, the positional relationship between the opening 9 provided in the partition 8 and the elevating pin 15 is such that when the substrate 12 is moved horizontally from the opening 9 and is carried into the furnace body 2, the substrate 12 is directly placed on the elevating pin 15. It is set so that it can be mounted on.

The operating parts in the furnace body 2 are a vertical drive plate 24 and a lifting pin 15 which are raised and lowered by the lifting means 11. The lifting means 11 is arranged outside the furnace body 2, and the substrate 12 is horizontally moved from the opening 9. Is carried into the furnace body 2 so that the vertical drive plate 2
It is sufficient if there is a space required for driving the substrate 4 and the driving range of the lifting pins 15 and the space required for carrying in the substrate 12.

On the upper surface of the hot plate 16, the substrate 12
And a plurality of vacuum suction holes 20 arranged at regular intervals. The displacement prevention pin 19 is a rod-shaped member that is detachably fixed to the hot plate 16 by screwing or the like so that the fixing position can be changed according to the shape of the substrate 12, and the substrate 12 is mounted thereon. The portion is provided so as to surround the portion from the periphery, and is positioned, for example, on the four sides of the rectangular substrate 12.

Inside the hot plate 16, a heating heater 22 and a vacuum pipe 21 connected to the vacuum suction hole 20 are provided.
And a vacuum pump (not shown) that is driven and controlled by the control unit 3 is connected to the vacuum pipe 21.

An air supply pipe 23 is provided as an air supply means on the side of the opening 9 at the upper inside of the furnace body 2. The air supply pipe 23 is a pipe-shaped pipe provided with a number of nozzles directed substantially in the horizontal direction on the side opposite to the opening 9, and allows gas (for example, nitrogen gas) to pass therethrough and pass through the furnace body from these nozzles. Air is supplied into 2.

An exhaust pipe 13 for exhausting dust generated in the furnace body 2 and gas generated by the hardening treatment of the sealant is provided on the surface of the partition wall 8 facing the opening 9. I have. In order to increase the internal pressure in the furnace body 2, the air supply pipe 23
The amount of exhaust gas from the exhaust pipe 13 is smaller than the amount of nitrogen gas supplied by the exhaust gas.

As shown in FIG. 2, the loading and unloading of the substrate 12 from the outside into the furnace body 2 has a transfer head having a shape as shown in FIG.
For example, a transfer robot 14 that operates in conjunction with 5 is used.

Next, the operation of the heating furnace configured as described above will be described with reference to FIG. FIG. 5 is a view of the opening 9 side from the dividing line CC of FIG. 2 as in FIG.

First, as shown in FIG.
2 is carried into the furnace body 2 from the opening 9 in the horizontal direction by the carrying-in robot 14 (FIG. 2), and is mounted on the ascending / descending elevating pins 15. At this time, hot plate 16
Is maintained at a desired temperature above the critical temperature at which the sealant applied to the substrate 12 rapidly cures. Since the hot plate 16 is isolated from the outside air by the partition wall 8, its temperature is stable, and the inside of the furnace body 2 is kept at a higher temperature than the outside air temperature by the heat of the hot plate 16.

The air supply pipe 23 always blows out a nitrogen gas at a normal temperature from its nozzle substantially horizontally in a direction opposite to the opening 9. The nitrogen gas supplied from the nozzle of the air supply pipe 23 has a high degree of cleanliness, and the supply of this nitrogen gas maintains the inside of the furnace body 2 with a high degree of cleanliness. Further, the exhaust pipe 13 (FIG. 2) always exhausts the air in the furnace body 2,
Slight dust generated in the furnace body 2 and gas generated by heating the sealant are exhausted.

When the substrate 12 is carried into the furnace body 2, the substrate 12 emits radiation from the hot plate 16, far-infrared rays which pass through the substrate 12 and are reflected by the mirror- finished inner surface of the partition 8. The surface temperature of the furnace body 2 rises due to the temperature inside the furnace body 2. At this time, the interval between the substrate 12 and the hot plate 16 differs depending on conditions such as the temperature of the hot plate 16 and a sealant.

Next, as shown in FIG. 5B, the lifting pins 15 are lowered by the lifting means 11 (FIG. 3), and
2 is held close to the hot plate 16. At this time, the interval between the substrate 12 and the hot plate 16 differs depending on a desired preheating temperature. In this state, the radiation of the hot plate 16 and the radiation through the substrate 12
Is heated by the far-infrared ray reflected on the mirrored inner surface of. Although the temperature of the substrate 12 further increases,
Is not distant from the hot plate 16 and does not rise to the surface temperature of the hot plate 16. Therefore, substrate 1
By adjusting the distance between the substrate 2 and the hot plate 16, the upper and lower surfaces of the substrate 12 can be preheated to a desired temperature.

When the temperature of the substrate 12 reaches a desired temperature, the elevating pin 15 is further lowered, and the above-described vacuum pump connected to the vacuum pipe 21 is operated to suck air from the vacuum suction hole 20.

Then, as shown in FIG.
By further lowering the substrate 5, the substrate 12 is lowered by being surrounded by the displacement prevention pins 19, and is finally mounted on the hot plate 16. Then, the substrate 12 is vacuum-adsorbed to the hot plate 16 and closely fixed by the operation of the vacuum suction holes 20. In this case, since the substrate 12 is preheated as described above, the substrate 12 hardly warps. However, even if the substrate 12 slightly warps, the substrate 12 is tightly fixed to the hot plate 16 by the above-described hot plate.
There is no gap between the heating unit and the heating unit, and no displacement occurs during heating.

It is difficult for the entire surface of the substrate 12 to simultaneously contact the hot plate 16 due to the warpage of the substrate 12 and the working accuracy of the hot plate 16 and the elevating pins 15. For this reason, the substrate 12 is drawn to the vacuum suction hole 20 from the portion that first comes in contact with the hot plate 16 and tends to shift from the mounting position therewith. The deviation is prevented within a desired range. The substrate 12 is kept in close contact with the hot plate 16 for a desired time.

The entire surface of the substrate 12 is brought into close contact with the hot plate 16, so that a uniform temperature is obtained by heating by heat conduction. Thereby, the sealant applied to the substrate 12 is uniformly heated and cured.

After holding the substrate 12 on the hot plate 16 for a desired time, the suction by the vacuum suction holes 20 is stopped, the lifting pins 15 are raised, and the substrate 12 is raised and lowered again as shown in FIG. Return to the position mounted on the pin 15 and hold it. At this time, the substrate 12 separates from the hot plate 16 and the temperature gradually decreases.

Further, when the substrate 12 separates from the hot plate 16, the nitrogen gas blown from the nozzle of the air supply pipe 23 is blown onto the surface of the substrate 12.
2 promotes cooling. The cooling by the nitrogen gas can prevent the hardening of the sealant due to the residual heat of the substrate 12.

The time-dependent changes in the positions of the lifting pins shown in FIGS. 5A to 5D depend on the characteristics of the sealant applied to the substrate 12 and various conditions such as the set temperature of the hot plate 16. different. When the temperature of the substrate 12 reaches a desired value and the cooling is completed, the transfer robot 14 (FIG. 2)
2 is carried out of the furnace body 2, and the heat curing of the sealant on the substrate 12 is completed.

As described above, by preheating the substrate 12 at a position away from the hot plate 16, the substrate 12 is preheated at a temperature lower than the critical temperature, and the time during which the substrate 12 adheres to the hot plate 16 is adjusted. By separating from the hot plate 16 after heating and cooling to a temperature lower than the critical temperature, desired properties of the sealant can be obtained.

By covering the hot plate 16 with the partition wall 8, the hot plate 16 is hardly affected by the outside air.
This is because not only the lower surface is heated by the hot plate 16 but also the far-infrared ray reflected on the mirrored inner surface of the partition 8 is absorbed by the sealant provided on the upper surface and the upper surface is also heated. The surface temperature of the substrate 12 is stabilized, and the substrate 12 can be heated at a uniform temperature.
Can be uniformly heated and cured.

The far infrared rays reflected on the mirror-finished inner surface of the partition 8 and passed through the substrate 12 return to the hot plate 16, and the far infrared rays heat the hot plate 16. Therefore, energy for heating the hot plate 16 itself can be saved, and energy saving can be further promoted.

Since the driving unit of the furnace body 2 is only the elevating means 11 for raising and lowering the elevating pins 15, the structure is simplified, and the control of the driving unit of the furnace body 2 is performed at the vertical position of the elevating pins 15. Simplify. The transfer robot 14 loads the substrate 12 from the opening 9 provided on the front surface of the partition 8, mounts the substrate 12 on the elevating pins 15, and unloads the substrate 12 on the elevating pins 15 at the same position after heating is completed. Easy to control.

In the furnace body 2, a vertical drive plate 2
The low-temperature outside air enters from the part where the partition wall 8 is notched into the ascending / descending area of 4, and moves along the hot plate 16 to generate an airflow flowing out of the opening 9. However, the nozzle of the air supply pipe 23 is opened. By being provided in a substantially horizontal direction on the opposite side to 9, airflow toward opening 9 is canceled.

Since the internal pressure in the furnace body 2 is slightly increased by the nitrogen gas supplied from the air supply pipe 23,
The airflow that tries to enter from outside is canceled out. Since the volume surrounded by the partition 8 can be suppressed, the space around the hot plate 16 is small,
With the heat of 6, the temperature inside the furnace body 2 is easily made uniform, the temperature difference between the upper part and the lower part inside the furnace body 2 becomes small, and the amount of convection generated can be suppressed. Since the convection is not disturbed by the movement of the substrate 12, the heating temperature of the hot plate 16 is made uniform,
The sealant applied to 2 can be uniformly heated and cured.

Since the gas supplied from the air supply pipe 23 is nitrogen gas, which is an inert gas, and the invasion of outside air is suppressed, the concentration of nitrogen gas in the furnace body 2 becomes high, and oxidation of the sealant can be prevented. .

Although the nozzle direction of the air supply pipe 23 is provided substantially in the horizontal direction on the opposite side to the opening 9, the nozzle direction and the air supply amount of the air supply pipe 23 depend on the position of the opening 9 of the partition wall 8 and the hot plate. The optimal nozzle direction and air supply amount of the air supply pipe 23 can be changed by the direction and flow rate of convection generated by the position and temperature of the nozzle 16. As an example, when the total height of the partition walls 8 is low and convection inside is suppressed,
It is also possible to form an air curtain by generating an airflow flowing along the opening 9 of the above to suppress the invasion of outside air.

In this heating furnace, the number of the furnace bodies 2 is four. The appropriate number of the furnace bodies 2 is a value obtained by dividing the total time of the time when the substrates 12 are present in the furnace body 2 and the time for loading and unloading the substrates 12 into and from the furnace body 2 by the desired substrate 12 supply time. Become. The substrates 12 having been subjected to the heat-curing process of the sealant are taken out at regular intervals by sequentially loading the substrates 12 into the furnace bodies 2 at regular intervals and taking out the substrates 12 after the heat-curing treatment of the sealant in order. It can be supplied to the next device.
Therefore, by providing a plurality of furnace bodies 2, the substrate 12
Can be supplied to the next-stage device or the like.

Even if one of the plurality of furnace bodies 2 fails, the temperature can be controlled individually for each furnace body 2 so that the furnace body 2 can be operated without the failed furnace body 2, and the manufacturing can be performed. Maintenance can be performed without stopping the line.

The inspection door 10 (FIGS. 2 and 4) for performing maintenance and inspection is provided on a side surface perpendicular to the surface on which the substrate 12 is carried in. Therefore, the inspection door 10 on one side is opened to perform maintenance and inspection. Does not hinder the loading of the substrate 12 into the furnace body 2 except for maintenance and inspection, and does not stop the entire heating furnace.

In this heating furnace, the furnace body 2 is vertically
Although two rows were arranged on the left and right sides, the furnace body 2 was arranged on the substrate 1
It may be changed by a combination with the transfer robot 14 for transferring the second. The furnace body 2 may be arranged only in the vertical direction, or may be arranged only in the horizontal direction. The arrangement of the furnace body 2 can be appropriately selected depending on conditions such as the floor area and the height of the room in which the furnace body is installed, the number of furnace bodies, the transfer range of the transfer robot 14, and the like. Since the total height of the furnace body 2 is low, even if the furnace bodies 2 are stacked in a plurality of stages in the vertical direction, the installation area can be reduced without increasing the overall size.

Further, in this heating furnace, the convection is suppressed to suppress the invasion of the outside air into the furnace body 2, and the cleanliness is increased to prevent the dust from adhering to the substrate 12. The number of times that the substrate 12 touches the hot plate 16 during heating is only once, and since the substrate 12 is mounted from a preheating position very close to the hot plate 16, the turbulence of the airflow around the hot plate 16 is small. In addition, it is possible to maintain cleanliness with little dust.

Since the contact area between the substrate 12 and the lifting pins 15 is small, the generation of dust due to the friction between the substrate 12 and the lifting pins 15 is suppressed. Since the convection inside the furnace body 2 is suppressed, the generated dust is difficult to move upward, and the substrate 1
2 can be maintained. Further, since the lifting / lowering means 11, which is a driving portion, is outside the partition 8, the amount of dust generated inside is small, and furthermore, the generated dust is exhausted by the exhaust pipe 13, so that the internal cleanliness can be kept good. As a result, it is possible to obtain a high-quality substrate 12 with less dust.

FIG. 6 is a cross-sectional view showing a modification of the heating furnace shown in FIGS. 1 to 5, in which 26 is a mirror, and portions corresponding to FIG. A duplicate description will be omitted.

In the heating furnace shown in FIG . 1, the inner surface of the partition 8 facing the upper surface of the hot plate 16 is mirror-polished in FIG. 3, but in this heating furnace shown in FIG.
Instead of making the inner surface of the partition 8 a mirror surface, the hot plate 1
A heat-resistant mirror 26 is fixed to the inner surface of the partition wall 8 facing the upper surface of the mirror 6 by a hook or the like (not shown).

This heating furnace is also shown in FIGS.
Similarly to the heating furnace , far infrared rays that have passed through the substrate 12 from the hot plate 16 are reflected by the mirror 26 and return to the substrate 12 and the hot plate 16 again.

As a result, the same effects as those of the heating furnace shown in FIGS. 1 to 5 can be obtained. Further, when the mirror 26 becomes dirty, the mirror 26 can be removed and the lower surface can be easily cleaned, so that the mirror 26 is always uniform. It can be in a heated state.

FIG. 7 is a sectional view showing an embodiment of the heating furnace according to the present invention, wherein 9a and 9b are openings, 27 is a horizontal frame, 28 is a supporting column, 29 is a shielding plate, 30 is a supporting material, 31
Denotes a shielding plate, and portions corresponding to those in FIG. 3 are denoted by the same reference numerals, and redundant description is omitted.

In this embodiment , the hermetically sealed state in the furnace body 2 is further improved.

FIG. 7A shows a state when the substrate 12 is loaded. In this case, the opening 9 for loading the substrate 12 is naturally open. However, FIGS.
In the heating furnace indicated by , the opening 9 is kept open even when the furnace body 2 performs the heating operation of the substrate 12.

In this embodiment , in FIG. 7 (a), the vertical drive plate 24 is placed on the side of the partition 8 on which the opening 9a (corresponding to the opening 9 in FIG. 3) is provided. Extending to the side surface, a horizontal frame 27 is provided at the end thereof in a direction perpendicular to the paper surface, and a shielding plate 29 for closing the opening 9a via a support pillar 28 is provided thereon.

Further, an opening 9b through which the vertical driving plate 24 penetrates is provided on the rear surface side of the partition 8 opposite to the opening 9a, and the vertical driving plate 24 moves up and down. The size is set to the extent possible. First, FIGS.
In the heating furnace described in the above section, such an opening is also formed, but as in the case of the opening 9, the opening is always open.

On the other hand, in this embodiment , FIG.
As shown in (a), a support member 30 is also provided on the side of the opening 9b of the vertical drive plate 24, and a shielding plate 31 for closing the opening 9b is provided.

When the substrate 12 is loaded in the state shown in FIG. 7A and the vertical drive plate 24 is lowered by the lifting / lowering means 11,
As shown in FIG. 7B, the shielding plates 29 and 31 also descend,
The shielding plate 29 shields the opening 9a, and the shielding plate 31 shields the opening 9b. Thereby, the inside of the furnace body 2 is completely sealed. When the vertical drive plate 24 is lifted after the heat treatment, the opening 9a is opened, and the substrate 12 can be taken out.

As described above, during the heating of the substrate 12, the opening 9
By closing a and 9b, there is no possibility that cold outside air containing dust flows in from outside the furnace, and more uniform heating and higher cleanliness can be obtained.

Further, since it becomes difficult for the high-temperature nitrogen gas in the furnace to flow out of the furnace, the amount of nitrogen gas supplied from the gas supply pipe 23 can be reduced.
Since a and 9b are opened, cool outside air flows in and the substrate 12 is cooled.

In the above embodiments, a liquid crystal or plasma display substrate has been described as an example.
If the substrate is made of glass, it is needless to say that the present invention can be applied to firing of a conductive paste applied to the substrate.

[0092]

As described above, according to the present invention,
The sealant or paste applied to the surface of the substrate can be uniformly heated and cured, and the outside of the container can be removed while the substrate is being heated.
Thus, it is possible to prevent cold external air containing dust from flowing into the apparatus, to manufacture a high-quality substrate, and to reduce the installation area of the apparatus.

[Brief description of the drawings]

FIG. 1 is an external front view showing a basic configuration of a heating furnace according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

FIG. 4 is a sectional view taken along the section line CC of FIG. 2;

FIG. 5 is an operation explanatory view of the heating furnace shown in FIG. 1;

FIG. 6 is a longitudinal sectional view showing a modification of the heating furnace shown in FIGS.

FIG. 7 is a longitudinal sectional view showing one embodiment of the heating furnace according to the present invention.

FIG. 8 is a longitudinal sectional view showing an example of a conventional heating furnace.

FIG. 9 is a sectional view taken along the line EE in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stand frame 2 Furnace 3 Control part 4 Base plate 5 Support 6 Frame 8 Partition wall 9 Opening 10 Inspection door 11 Elevating means 12 Substrate 13 Exhaust pipe 14 Transfer robot 15 Elevating pin 16 Hot plate 17 Support 18 Heat dissipation prevention cover DESCRIPTION OF SYMBOLS 19 Position shift prevention pin 20 Vacuum suction hole 21 Vacuum piping 22 Heating heater 23 Air supply pipe 24 Vertical drive plate 25 Horizontal frame 26 Mirror 27 Horizontal frame 28 Support column 29 Shielding plate 30 Supporting material 31 Shielding plate

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-97269 (JP, A) JP-A-50-101936 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C03B 32/00-32/02 F27B 5/12 F27B 9/12

Claims (3)

(57) [Claims] 1. A heating furnace for heating equipped with a substrate on a heated plate, a plurality of small holes penetrating the heating plate, above the said heated plate at a plurality of small diameter rod shape through the said small holes a holding means of a substrate arranged projecting to a lifting means for raising and lowering the holding means of the substrate, controls the length of the holding means of the substrate projecting upwardly from said heating plate, preheating, main heating and cooling Temperature control for each temperature
As means for controlling the elevating means intercepts the outside air includes retaining means of the heating plate and the substrate, and a container inner surface facing at least the heating plate forms a mirror surface on one surface of the container An opening is provided for horizontally moving the substrate and mounted on the holding means of the substrate in the container , the elevating means is disposed outside the container , and the elevating means and the elevating means are provided on another surface of the container. Board holding means
An elevating port of the elevating means through which a driving plate to be connected penetrates is provided, and the elevating port of the container and the elevating port of the elevating means are respectively provided.
A heating furnace provided with a shielding plate that opens and closes in accordance with elevation of the means . 2. The heating furnace according to claim 1, wherein the inner surface of the container is a mirror-polished surface . 3. The heating furnace according to claim 1, wherein the substrate is made of glass.