JP2003124609A - Heat treatment method using auxiliary plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a substrate from rotation, shifting, printing unevenness, a defect in conveyance, cracking, flawing, or the like since an auxiliary plate and the substrate differ in way of getting cooled due to a difference in thermal capacity and the substrate worps owing to the temperature difference between the both as to a method for heat-treating the substrate by using the auxiliary plate. SOLUTION: The method for heat-treating substrates 4 and 6 by carrying the substrates 4 and 6 in a plurality of heating rooms 1, 2, and 3 one after another by using auxiliary plates 5 and 7 is provided with a soaking process of cooling or heating the auxiliary plates 5 and 7 independently and soaking them while keeping a worp quantity per specified unit area within a specified range and can suppress the deviation and rotation of the auxiliary plates 5 and 7, and substrates 4 and 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a thick film wiring substrate, a display panel substrate using a liquid crystal, an electron beam, discharge, fluorescent light, a solar cell panel substrate, a thermal printer head or an image sensor. The present invention relates to a heat treatment method for a substrate provided with a functional film material such as a substrate for an electronic device, in particular, a heat treatment method for heat treating a substrate using an auxiliary plate.

[0002]

2. Description of the Related Art In recent years, in the field of various electronic devices, a functional film material made of a metal, an inorganic material or an organic material has been applied on a ceramic substrate by coating, printing, die coating,
A substrate formed over the entire surface by various methods such as sheet attachment, vacuum deposition, sputtering, or a substrate patterned by photolithography or masking is used. For example, in a display panel substrate, metal wiring such as an electrode / transparent electrode film, an insulator or dielectric that maintains insulation, partition walls separating a plurality of phosphors, an electron emission film, or in a solar cell panel substrate, a metal wiring / transparent Functional film materials such as an electrode film, an insulator that maintains insulation, a metal wiring, a resistor, and an insulator are also formed in a thick film wiring substrate and an electronic device substrate.

These functional film materials are improved in adhesion by heat diffusion of materials, adjustment of crystal orientation, melting of metal at the interface,
Heat treatment is performed for the purpose of maintaining and strengthening an appropriate resistance value, shape, and removing unnecessary substances. In addition, this heat treatment is
Temperature increase, constant temperature, temperature decrease of the material to be processed, or a combination thereof, which is to raise or lower the temperature of the material to be treated,
Alternatively, it may be a constant process or a combination of these processes.

In order to increase the productivity of a relatively time-consuming process such as the heat treatment required for forming these functional film materials, for example, the material to be treated is conveyed by a mesh belt conveyor, a roller hearth or the like, and is dome-shaped or tunnel-shaped. An apparatus for performing heat treatment by passing through the heating furnace is generally used.

On the other hand, on the other hand, in forming functional film materials, multilayer wiring and miniaturization of patterned wiring and the like are increasingly required, and in particular for display panels and solar cell panels, it is required to enlarge the substrate. ing. Under these requirements, conventional heat treatment temperature variations cannot be ignored when heat treatment is performed in the heating furnace, and it is accelerating that variations in heat treatment greatly affect product quality. For example, variations in the heat treatment temperature of the substrate affect variations in resistance value and instability in connection of electrode terminals in metal wiring and resistors, and in variations in withstand voltage due to defects in insulators and dielectrics. To do. In addition, the dimensional variation of the formed pattern caused by the residual strain at the time of expansion and contraction due to the variation of the heat treatment temperature of the substrate is
There is a problem that it becomes difficult to overlap when repeating the multi-layering, and in severe cases, microcracks due to residual stress may destroy the formation pattern, the insulator / dielectric, or even the substrate itself.

In response to these problems, various heat treatment methods and apparatuses have been actively developed. Especially in the most important cooling process during heat treatment, the substrate on which the functional film material is formed is soaked in a heating chamber where it is maintained at a set temperature that is set for each chamber so that it gradually decreases along one direction. It is considered that the temperature variation in the substrate on which the functional film material is formed is minimized by performing the cooling process of the heat treatment while repeating the above.

According to this method, the dimensional change in the substrate and the distortion of the formed pattern are reduced, the overlay accuracy is improved even in the case of a fine pattern or a large substrate, and the thick film dielectric formed on the surface of the substrate, Barrier rib dielectric, thick film resistor,
The size of the functional film such as the electrode layer and the variation in each characteristic are suitably reduced.

On the other hand, in terms of performance, especially for display panels, solar cell panels, etc., which are required to have optical characteristics, the standards are strict with respect to scratches, and heat treatment is time-consuming to achieve cost reduction. Sometimes it is necessary to process many substrates at once. At this time, a method of placing one or a plurality of substrates on an auxiliary plate to perform heat treatment is used. However, when a heat-treated unit including the auxiliary plate and the substrate is processed in a predetermined heating chamber, the above-mentioned conventional method is used. In the method, because of the difference in heat capacity between the auxiliary plate and the substrate, uniform heating cannot be achieved and cooling is different. Also, the temperature difference between the two causes the substrate to warp, causing the substrate to rotate or shift on the auxiliary plate, causing uneven baking,
There have been new problems such as poor conveyance, substrate cracks, and scratches.

FIG. 5 is a diagram showing the basic concept of the conventional heat treatment method. With the heating chamber 102 as a reference, the heating chambers before and after the heating chamber 102 are added, and the room temperature is gradually set low in the substrate transport direction. Heating chambers 101, 102, 103 (set temperature is T1>
(T2> T3) is arranged. Each heating chamber 10
1, 102, 103 include air supply pipes 111, 113, 11
5 and the exhaust pipes 112, 114 and 116, and the heater 12
1, 122 and 123, and substrate transfer rollers 131 and 13
2 and 133 are arranged.

First, in the process of FIG.
Heating chambers 101 and 102 (set temperature is T
The substrates 105 and 106 are soaked at each set temperature of 1> T2). At this time, the heating chamber 103 is cooled by the gas 117 having a temperature lower than the set temperature of the heating chamber 103 supplied and exhausted by the air supply pipe 115 and the exhaust pipe 116, and then heated to a predetermined temperature by the heater 123 to change the temperature. Control.

Next, in the step of FIG. 5B, the heating chamber 10
The second substrate 106 is transported to the temperature-controlled heating chamber 103 by using the transport roller 132. Substrate 106 here
Is soaked to a predetermined temperature. Then, in the process of FIG. 5C, in the heating chamber 102 from which the substrate 106 has been carried out, the heating chamber 1 is supplied and exhausted through the air supply pipe 113 and the exhaust pipe 114.
The temperature is controlled by being cooled by the gas 117 having a temperature lower than the set temperature of 02, and then being heated to a predetermined temperature by the heater 122.

In the step of FIG. 5D, the substrate 105 in the heating chamber 101 is transferred to the temperature-controlled heating chamber 102 by using the transfer roller 131. Here, the substrate 105 is uniformly heated to a predetermined temperature.

The above operation is repeated to cool the substrate.

[0014]

However, the conventional heat treatment method has the following problems when heat treating the substrate using the auxiliary plate in order to prevent scratches and take a large number of wafers.

In the case of a single substrate, the method of stepwise loading a substrate into a chamber that maintains a preset temperature as in the conventional example is more effective in the substrate transport direction than the continuous cooling process. Certainly, the temperature variation in the substrate is dramatically improved. However, when the substrate is placed on the auxiliary plate, the auxiliary plate and the substrate have different heat capacities, so that the cooling rate profile differs between the auxiliary plate and the substrate.

FIG. 6 shows a state in which a substrate placed on a predetermined auxiliary plate is cooled stepwise as shown in the conventional example when the heat capacity of the auxiliary plate is larger than that of the substrate. Reference numeral 51 is an auxiliary plate temperature profile, and 52 is a substrate temperature profile. For example, if the cooling process starts at a point of the cooling process start time 54 after being kept at a constant temperature, the first chamber of the cooling process is soaked at a temperature lower than the constant temperature maintaining temperature by a predetermined temperature. ing. The substrate and the protective plate sent to the first room are cooled in the atmosphere, but since the thermal capacities of the substrate and the auxiliary plate are different,
A temperature difference is generated while the first cooling time 55 is accommodated for a predetermined time. The second of the cooling process while maintaining the temperature difference
The second cooling time 5
There is a point at which the maximum temperature difference 53 between the substrate and the auxiliary plate is further generated while being accommodated for the predetermined time of 6. Here, it is assumed that it occurs in the second cooling time. Further, by repeating the above, eventually the fifth cooling time 57
The temperature of the auxiliary plate approaches the temperature of the substrate, as in the area.

At this time, the temperature difference in the thickness direction of the substrate becomes higher on the surface of the substrate on the side of the auxiliary plate than on the opposite surface, and warpage 58 of the substrate 61 occurs as shown in FIG. When the warp 58 of the substrate 61 occurs, the contact area with the auxiliary plate 62 becomes extremely small, the substrate 61 itself easily rotates 59 on the auxiliary plate 62, and the difference in the transfer speed during loading / unloading. The deviation 60 is apt to occur when acceleration is generated due to the occurrence of.

As shown in FIG. 8, the substrate 61, which has deviated from the predetermined arrangement 63 due to rotation or displacement on the auxiliary plate 62, protrudes from the soaking area 64, or the substrates 61 overlap with each other to cause scratches. In severe cases, the substrate 61 may even stick out of the auxiliary plate 62 and become untransportable.

The present invention solves the above-mentioned problems, and in consideration of the difference in heat capacity between the auxiliary plate and the substrate, the soaking is performed while maintaining the amount of warpage per unit area in accordance with each heat capacity, so that the performance is improved. It is an object of the present invention to provide a heat treatment method which realizes high yield and cost reduction.

[0020]

In order to achieve this object, the heat treatment method of the present invention is arranged such that each heat-treated unit is placed in a plurality of heat treatment chambers whose temperatures are set so as to gradually decrease in one direction. Each of the units to be heat treated is set for each heat treatment chamber while accommodating and cooling or heating independently depending on the heat capacity of each of the auxiliary plate and the substrate to maintain the amount of warpage per predetermined unit area within a predetermined range. A soaking process for soaking at a temperature is provided.

With this structure, the cooling and heating of the auxiliary plate and the substrate are independently controlled according to their respective heat capacities, so that the warp of the substrate is suppressed, the rotation or displacement of the substrate is prevented, and scratches and cracks are prevented. Preventing, ensuring uniform heat distribution of the substrate, preventing troubles related to stopping inside the heat treatment equipment, dramatically improving the product yield, preventing substrate distortion, improving pattern accuracy, even for large substrates and fine patterns. By improving the pattern overlay accuracy, it is possible to manufacture a highly accurate and high-performance substrate.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS That is, according to the invention described in claim 1 of the present invention, one or a plurality of substrates provided with a functional film material made of a metal, an inorganic material, or an organic material are arranged on an auxiliary plate. In this method, a plurality of units to be heat treated are sequentially conveyed in one direction to perform heat treatment, and the temperature is set so as to gradually decrease in one direction in the cooling process of the heat treatment. Each of the heat-treated units is housed in each of the plurality of heat treatment chambers for a predetermined time and independently cooled or heated according to the heat capacity of each of the auxiliary plate and the substrate to maintain a predetermined amount of warpage per unit area within a predetermined range. At the same time, the soaking step of soaking each of the heat treated units at the set temperature of each heat treatment chamber, the carry-out step of sequentially sending out the plurality of heat treated units to the plurality of heat treatment chambers, and the heat treated units are A cooling medium supply step of supplying a cooling medium to the predetermined heat treatment chamber that has been ejected, and a carry-in step of feeding the next unit to be heat-treated into the predetermined heat treatment chamber after the cooling medium supply step. Therefore, when the auxiliary plate and the substrate having different heat capacities are heat-treated at the same time, an effect of suppressing the warp of the substrate on the auxiliary plate can be obtained.

Here, in the present invention, the unit to be heat treated is cooled or heated from the auxiliary plate side such that the substantially central portion of the auxiliary plate has a higher cooling or heating capacity than the end portions or is equivalently controlled. It is configured.

Further, the auxiliary plate may be controlled or cooled from the substrate side of the unit to be heat-treated so that the substantially central portion of the auxiliary plate has a higher cooling or heating capacity than the end portions or is in a state equivalent thereto. .

The invention according to claim 6 of the present invention is
From the plurality of substrate sides of the plurality of heat-treated units,
The end portions of the plurality of auxiliary plates have a higher heating capacity than the substantially central portion, or are controlled to be heated in an equivalent state, and intensively heat a low temperature distribution region of the substrate, It has the effect of reducing the temperature distribution.

Further, in the present invention, cooling or heating is performed from the auxiliary plate side and the substrate side, respectively, and each cooling or heating is independently controlled, thereby performing control according to the heat capacity of each of the auxiliary plate and the substrate. As a result, the temperature distribution can be adjusted while easily aiming at the region to be cooled.

A heat treatment method according to an embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 and 2 are views for explaining Embodiment 1 of the present invention and are views seen from the side of a heat treatment apparatus. Heating chambers 1, 2 and 3 (set temperatures) in which the room temperature is gradually set in the substrate transport direction by adding heating chambers 1 and 3 before and after the heating chamber 2 as a heat treatment chamber as a reference. T1>T2> T3) and each heating chamber 1, 2, 3 has an upper heater 11, 2,
1, 31, the lower heaters 12, 22, 32, and the air supply ports 13, 23, 33 and the exhaust ports 14, 2 arranged on the upper side.
4, 34 and the air supply ports 15, 25, 35 arranged in the lower part
And the exhaust ports 16, 26 and 36, and the transport rollers 17 and 2.
7, 37 are provided. Further, the heat-treated unit is configured by disposing the two substrates 4, 6 on the surfaces of which functional film materials such as metals, inorganic materials, and organic materials are provided on the auxiliary plates 5, 7. In this unit to be heat-treated, the auxiliary plates 5 and 7 have a smaller coefficient of thermal expansion than the substrates 4 and 6.

In the example of FIG. 1, an air supply port for blowing a gas as a cooling gas and an exhaust port for discharging the cooling gas after cooling are provided at substantially central portions on the substrate side and the auxiliary plate side,
The air supply port and the exhaust port can be independently controlled so that the cooling capacity is higher than that at the end by spraying at the substantially central part of the substrate and the auxiliary plate, but it is heated or equivalent to the end. May be controlled to
Any structure may be used as long as the entire heating chamber can be controlled to a uniform temperature.

Next, the operation of the heat treatment method of the present invention will be described.

First, in the process shown in FIG. 1, the substrate 4 in the heating chamber 1 is cooled at a substantially central portion of the auxiliary plate 5 by blowing a gas as a cooling gas from the air supply port 13 on the upper surface. The cooled gas is discharged to the outside of the heating chamber 1 through the upper exhaust port 14. On the side of the auxiliary plate 5, cooling is performed from the lower surface according to the heat capacity of the auxiliary plate 5 so that the cooling rate is the same as that of the substrate 4.

Specifically, a plurality of air supply ports 1 are provided in the lower part of the heating chamber 1 and have higher cooling performance than the air supply port 13 in the upper part.
A gas is blown from 5 to cool intensively. The cooled gas is discharged to the outside of the heating chamber 1 through the exhaust port 16 at the bottom of the heating chamber 1. The in-plane cooling rate of the auxiliary plate 5 is high in the periphery and slow in the central portion. For this reason, the periphery is uniformly heated by using the upper heater 11 and the lower heater 12.

The heating chamber 2 is subjected to the same steps as the heating chamber 1. In the heating chamber 3, the substrates 4, 6 from the upstream heating chambers 1, 2 are
And the heat quantity brought in by the auxiliary plates 5 and 7 are supplied to the air supply ports 33 and 35.
Also, the inside of the heating chamber 3 is cooled to a predetermined temperature or lower by using the exhaust ports 34 and 36.

In the step shown in FIG. 2A, the substrate 4 and the auxiliary plate 5 in the heating chamber 1 are continuously cooled so as to be uniformly heated. In the heating chamber 2, after the heating chamber 3 has been cooled to a predetermined temperature or lower, the substrate 6 and the auxiliary plate 7 are unloaded into the heating chamber 3 using the transport rollers 27. In the heating chamber 3, the substrate 6 loaded from the heating chamber 2
A gas is blown from the air supply port 33 on the upper surface to cool the substantially central portion of the auxiliary plate 7. The gas after cooling is the exhaust port 3 at the top.
It is discharged to the outside of the heating chamber 3 through 4. The auxiliary plate 7 cools by blowing gas from an air supply port 35 provided in the lower part of the heating chamber 3 and having a higher cooling performance than the upper air supply port 33.
The cooled gas is discharged from the exhaust port 36 at the bottom of the heating chamber 3 to the heating chamber 3.
It is discharged outside.

In the step of FIG. 2B, the substrates 4 and 6 and the auxiliary plates 5 and 7 are continuously cooled in the heating chambers 1 and 3. In the heating chamber 2, the amount of heat emitted from the substrate 6 and the auxiliary plate 7 is cooled by using the air supply ports 23 and 25 and the exhaust ports 24 and 26, and the inside of the heating chamber 2 is cooled to a predetermined temperature or lower.

In the step of FIG. 2C, in the heating chamber 1, the substrate 4 is cooled after the heating chamber 2 is cooled to a predetermined temperature or lower.
Then, the auxiliary plate 5 is carried out by using the carrying roller 17. In the heating chamber 2, the substrate 4 carried in from the heating chamber 1 is blown with gas from the upper air supply port 23 to cool the substantially central portion of the auxiliary plate 5. The cooled gas is discharged to the outside of the heating chamber 2 through the exhaust port 24 in the upper part. A plurality of auxiliary plates 5 are provided in the lower portion of the heating chamber 2, and a cooling gas is blown from an air supply port 25 having an improved cooling performance than the air supply port 23 in the upper part to intensively cool.
The cooled gas is supplied from the exhaust port 26 at the bottom of the heating chamber 2 to the heating chamber 2.
It is discharged outside. In the heating chamber 3, the substrate 6 and the auxiliary plate 7 are continuously cooled so as to be uniformly heated.

The above operation is repeated to cool the substrate and the auxiliary plate.

According to the present invention, the temperature difference between the substrate and the auxiliary plate is reduced, so that the deformation of the substrate is suppressed and the displacement or rotation of the substrate causes deviation, damage or cracks from the soaking area on the auxiliary plate. It is possible to drastically improve the decrease in product yield caused by the above, and to prevent troubles that may occur in the transfer system of the apparatus or the apparatus itself due to the displacement or rotation of the substrate in the heat treatment apparatus.

FIG. 3 is a view for explaining the second embodiment of the present invention and is a view as seen from the side of the heat treatment apparatus. A cooling unit 18, 28, 38 is installed in the lower center of the heating chambers 1, 2, 3 to control cooling in a state where the cooling capacity is higher than or equal to the end portion, and the auxiliary plate 5, which is hard to be cooled,
The configuration is such that the substantially central portion of 7 is cooled intensively, and the substrate transfer process and the cooling process are the same as in the first embodiment. The cooling units 18, 28, 38 are configured to cool by passing a cooling medium through the pipes.

By the way, in a heating chamber in which the temperature is gradually lowered along one direction as shown in FIG. 1, the heating chambers are influenced by the adjacent heating chambers to some extent.
In the adjacent room, the room temperature on the side of the heating chamber 1 is high, the room temperature on the side of the heating chamber 3 is low, and the temperature distribution on the side of the heating chamber 1 is high and the temperature on the side of the heating chamber 3 is low in the substrate and the auxiliary plate. Occurs. Further, cooling progresses from the side closer to the wall surface of the heating chamber. Furthermore, this temperature distribution is also affected by the transport speed of the substrate and the auxiliary plate.

For this reason, the temperature distribution of the substrate and the auxiliary plate is set such that the end portion on the heating chamber side where the temperature is set low is low and the adjacent temperature is set high next to the direction parallel to the substrate transport direction. The temperature distribution is such that the end on the heating chamber side and the substantially central part are the highest, or the end on the heating chamber side where the temperature is set low is low and the end on the heating chamber side where the temperature is set high is The temperature distribution is approximately the same in the center.

On the other hand, with respect to the temperature distribution of the substrate and the auxiliary plate, cooling proceeds from the side closer to the wall of the heating chamber in the direction perpendicular to the substrate transport direction on the horizontal plane, so that the side closer to the wall of the heating chamber. The temperature distribution is low at the ends and highest at the center, or the temperature distribution is the same at the ends near the wall surface of the heat treatment chamber and at the center.

That is, to explain the heating chamber 2,
The air supply port 25 or the cooling unit 28 has the function of intensively cooling the region of the auxiliary plate 7 having a high temperature distribution and reducing the temperature distribution, and corrects the complicated temperature distribution to perform uniform cooling. Therefore, the cooling capacity of the lower part of the center of the auxiliary plate 7 of the air supply port 25 or the cooling unit 28 is controlled to be higher than or equal to that of the end portion to reduce the temperature distribution.

Further, the lower heater 22 intensively heats a region of the auxiliary plate 7 having a low temperature distribution to reduce the temperature distribution. As compared with the case where only the cooling is performed, the temperature distribution can be controlled more easily by controlling so that the heating capacity is higher or equivalent, and by heating the end portion intensively.

Similarly, the air supply port 23 has a function of intensively cooling a region of the substrate 6 having a high temperature distribution to reduce the temperature distribution, and the substrate 6 from the upper portion of the substrate 6 is hard to be cooled. By controlling the substantially central portion of the substrate 6 to have a cooling capacity higher than or equal to that of the end portion, a region where the temperature distribution of the substrate 6 is high is intensively cooled to reduce the temperature distribution.

Further, the upper heater 21 has a function of intensively heating a region of the substrate 6 having a low temperature distribution to reduce the temperature distribution. By controlling in a state where the heating capacity is higher than or equal to the heating capacity, the region where the temperature distribution of the substrate 6 is low is intensively heated and the temperature distribution is reduced.

That is, by using the above cooling and heating means alone or in combination, the deformation of the substrate is suppressed, and the displacement, scratches or cracks from the soaking area on the auxiliary plate caused by the displacement or rotation of the substrate. It is possible to drastically improve the decrease in product yield caused by the above, and to prevent troubles which may be caused in the transfer system of the apparatus or the apparatus itself due to the displacement or rotation of the substrate in the heat treatment apparatus.

In the heating chamber 2 shown in FIGS. 1 and 3, the air supply ports 23 and 25 serve to adjust the temperature distribution while easily aiming at the region to be cooled, and the auxiliary plate 7 and the substrate 6 are provided. Can be cooled according to each heat capacity, and the cooling gas injected from the air supply ports 23 and 25 is directly injected, and the cooling gas injected from the plurality of air supply ports is independently controlled, thereby cooling It is possible to cool while aiming at the desired region and adjusting the temperature distribution.

Further, the cooling unit 2 as shown in FIG.
8 has a function of adjusting the temperature distribution while preventing the dust from being rolled up. By disposing the cooling units 28 on both sides of the auxiliary plate 7 side and the substrate 6 side and controlling each independently, The plate 7 and the substrate 6 can be indirectly cooled according to their respective heat capacities, and the temperature distribution can be adjusted while preventing the dust from being rolled up. Furthermore, the above 2
It is also possible to combine and use different types of cooling means.

Here, the cooling gas injected from the air supply port is an acid.
It also enables gasification, oxidation prevention, and gas cooling in a reducing atmosphere.
Therefore, the air from which foreign substances have been removed using a filter is usually used.
Can be It is necessary to perform heat treatment in an oxidizing or reducing atmosphere.
If necessary, consider the changes in the concentration of atmospheric gas components,
The same kind of atmosphere as the atmosphere gas is used as the cooling gas. Return
CO, H as the gas having the original action₂The single gas of
Is N₂With low reactive gases such as He, Ar, Xe
A mixed gas is used, and O is used as a gas having an oxidizing action.₂of
Single gas or N₂, He, Ar, Xe, etc.
A mixed gas with a low gas is used. Oxidation and reduction
N to suppress and maintain substrate quality₂, CO₃, He,
Ar or Xe such as a gas with low reactivity may be used alone or mixed.
It is good to use. In addition, H for humidity control₂Single O
Gas or mixed gas is used. Especially, the characteristics of the substrate with a functional film
Effective gas is air, N₂, O₂, H₂O, CO, C
O₂, H ₂, He, Ar, Xe single gas or mixed gas
The gas that can be used is
Not limited to.

Further, the cooling unit is capable of suitably adjusting the cooling capacity of the cooling medium according to the environment of the apparatus, and water or air is usually used as the cooling medium. A cooling medium that matches the environment of the device is used in consideration of the management of the concentration of the components in the atmosphere or the leakage of the cooling medium from the cooling unit. As described above, gases effective for the characteristics of the substrate with a functional film, such as oxidation or reduction, are air, N ₂ , O ₂ , H ₂ O and C.
It is selected from a single gas or a mixed gas of O, CO ₂ , H ₂ , He, Ar, and Xe, but the cooling medium that can be used is not limited to this.

Next, in the actual heat treatment process for various substrates, the variation ΔT of the substrate temperature with respect to the set temperature T is measured, and after the presence or absence of rotation or displacement of the substrate is confirmed, the variation ΔT of the substrate temperature with respect to the set temperature T is measured. And the maximum amount of warpage δmax relative to this were measured and divided by the area of the substrate to obtain the amount of warpage Δδ per unit area. The results are shown in FIGS. 4 (a) and 4 (b).

FIG. 4A shows the warp amount per unit area of the substrate and the displacement amount of the substrate, and FIG. 4B shows the temperature difference of the substrate and the warp amount per unit area. Is. In FIG. 4, the condition that the substrate is not rotated and the displacement of 1 mm or more is indicated by a circle, and the condition that the substrate is rotated or the displacement of 1 mm or more is indicated by a cross.

In this embodiment, the diagonal is 42 inches and 1
The measurement was performed using a high strain point glass, a soda glass, and a SiC substrate having a 3-inch length-width ratio of 16: 9. The surface roughness Ry (Rmax) of each substrate is 0.1 μm or less, and the surface roughness Ry (Rmax) of the auxiliary plate is 10 μm.
m or less. In addition, the maximum transfer speed during board transfer is 6 m.
/ S, and the maximum acceleration is 20 m / s ² . The coefficient of thermal expansion increases in the order of soda glass, high strain point glass, and SiC substrate, and 90 × 10 ⁻⁷ (° C. ⁻¹ ) and 83 × 10 ⁻⁷ , respectively.
(° C. ⁻¹ ) and 3.8 × 10 ⁻⁷ (° C. ⁻¹ ).

In FIG. 4 (b), A to E are the characteristics when high strain point glass is used, and the set temperature A is 600.
℃, B is 500 ℃, C is 400 ℃, D is 300 ℃, E is 200 ℃. In addition, F to I are the characteristics when soda glass is used, and the set temperature is 500 ° C. for F and 400 for G.
C., H is 300.degree. C., and I is 200.degree. Also, J, K
Is the characteristic when SiC is used.
C and K are 600 ° C.

In FIG. 4A, only the main points in each sample shown in FIG. 4B are plotted and shown.

Next, a case where a 42-inch diagonal soda glass is used and the set temperature T is 200 ° C. will be described as an example. When the ratio ΔT / T to the temperature variation ΔT is 17%,
The amount of warpage Δδ per unit area was 0.032, and at this time, the substrate was deviated by 30.9 mm. On the other hand, when the ratio ΔT / T of the temperature variation to the set temperature was 12%, the amount of warpage Δδ per unit area was 0.022, and at this time, there was no displacement of the substrate and no rotation occurred.

Similarly, a case where a high strain point glass having a diagonal length of 13 inches is used and the set temperature is set to 600 ° C. will be described as an example. When the ratio ΔT / T of the temperature variation ΔT to the set temperature is 5%, the unit is The amount of warpage Δδ per area was 0.026, and the amount of deviation of the substrate was 0.7 mm. On the other hand, when the ratio ΔT / T of the temperature variation ΔT to the set temperature was 8%, the amount of warpage Δδ per unit area was 0.042, and a deviation of 39.8 mm occurred on the substrate. When the ratio ΔT / T of the temperature variation ΔT to the set temperature was larger than 8%, the high strain point glass was broken due to cracking.

Similarly, an experiment was conducted using the substrate size, type, and set temperature as parameters, and the amount of warpage Δδ per unit area and the amount of displacement of the substrate are plotted in FIG. 4 (a).
It is (b).

As shown in FIG. 4, a substrate material having a smaller coefficient of thermal expansion has a smaller amount of warpage per unit area even if the variation with respect to the set temperature is larger, and thus the substrate is less likely to rotate or shift. For example, a SiC substrate corresponds to this. On the other hand, a substrate material having a higher coefficient of thermal expansion has a larger amount of warpage per unit area with respect to temperature variations, and is likely to cause substrate rotation and displacement. For example, this is soda glass.

As a result of the experiment, regardless of the type of the substrate, the substrate does not rotate or deviate below a certain amount of warp per unit area, and conversely, when the amount of warping exceeds this amount, the amount of deviation abruptly increases. It has been found.

The warp amount per unit area under the condition of being positioned at the upper limit where the substrate is not rotated or displaced is set to 20 as a representative value, and an average value is obtained. It was found that the upper limit value of Δδ is Δδ = 0.028 (m ⁻¹ ) indicated by the solid line in each of the graphs of FIG. As mentioned above, this can be adapted regardless of the size and type of substrate.

That is, in the present invention, by defining the amount of warpage Δδ per unit area to be 0.028 or less,
It is possible to prevent rotation and displacement of the substrate.

Here, the amount of warp Δδ (m ⁻¹ ) per predetermined unit area is expressed by the following equation.

Δδ = [t {(α · ΔT) ⁻¹ +1}] ·
[1-cos {(D ・ α ・ ΔT) ・ (2t) ^-1 }] ・ S
^-1 where t: thickness (m), α: coefficient of thermal expansion, ΔT: temperature difference (° C), D: representative length of substrate (m), S: area of substrate (m ² ), and When the substrate is a square, D is a diagonal length (m) represented by D: (X ² + Y ² ) ^0.5 ,
X and Y are vertical and horizontal lengths (m) of the substrate, and S is S: X × Y.
Is an area (m ² ), and when the substrate is circular, D is a diameter (m) and S is an area (m ² ) represented by S: 0.25πD ² .

In the present invention, the auxiliary plate and the one or more substrates are independently cooled or heated according to their respective heat capacities, and a plurality of heat-treated units are maintained while maintaining a predetermined amount of warpage per unit area. In soaking each of them at the set temperature of each heat treatment chamber, generally the auxiliary plate has a larger plate thickness and a larger area than the substrate, so the heat capacity is large,
The temperature is less likely to change than that of the substrate, and a temperature difference between the surface of the auxiliary plate on the substrate side and the surface on the opposite side is likely to occur, so that the amount of warpage per unit area tends to increase.

Therefore, even if the coefficient of thermal expansion is small and the temperature variation is large as in the SiC substrate shown in FIG. 4, the amount of warpage per unit area is within the allowable value of the amount of warpage per unit area that causes rotation or deviation. By using a certain material, rotation or displacement of the substrate can be suppressed.

As a substitute material for the SiC auxiliary plate, it is possible to use a substrate having a small coefficient of thermal expansion, such as quartz, Pyrex glass, or mullite, zirconia, and alumina ceramic material.

In addition, as a means for preventing the rotation or displacement of the substrate, the auxiliary plate is made of a material having a large thermal diffusivity, or a high strength member is used to reduce the thickness. A means for reducing the temperature difference between the surface of the plate on the substrate side and the surface on the opposite side is also possible.

As is clear from the above description, the functional film-coated substrate heat-treated by the heat-treatment method of the present invention has less warpage of the substrate and no deviation of the substrate, so that the substrate does not come out of the soaking region. Therefore, a uniform functional film can be obtained, and substrate deformation and pattern distortion are small. by this,
It is easy to perform alignment between substrates and is suitable for processing substrates of display panels and solar cell panels that require highly accurate alignment technology.

[0071]

As described above, according to the present invention, since the cooling and heating of the auxiliary plate and the substrate are independently controlled according to their respective heat capacities, the warp of the substrate is suppressed, and as a result, the substrate The product yield can be improved by preventing the rotation or displacement and preventing scratches and cracks while ensuring the uniform heating of the substrate and preventing the troubles related to the stop in the heat treatment apparatus.

Further, according to the present invention, when applied to a display panel and a solar cell panel, the substrate is prevented from being distorted, the pattern accuracy is improved, and the pattern overlay accuracy is improved even with respect to a large-sized substrate or a fine pattern. The effect is obtained, and as a result, it is possible to manufacture a highly accurate and highly homogeneous display panel and solar cell panel.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus used for a heat treatment method according to a first embodiment of the present invention.

2A to 2C are schematic configuration diagrams for explaining a heat treatment step in the same method.

FIG. 3 is a schematic configuration diagram of an apparatus used for a heat treatment method according to a second embodiment of the present invention.

4 (a) and 4 (b) are characteristic diagrams showing a relationship between a substrate temperature difference, a warp amount per unit area of the substrate, and a substrate shift amount in the method of the present invention.

5A to 5D are schematic configuration diagrams for explaining a conventional heat treatment method.

FIG. 6 is a characteristic diagram showing cooling temperature profiles of an auxiliary plate and a substrate in a cooling process of a conventional method.

FIG. 7 is a perspective view showing warpage of a substrate in a conventional heat treatment method.

FIG. 8 is a plan view showing substrate displacement in a conventional heat treatment method.

[Explanation of symbols]

1, 2, 3 heating chamber 4, 6 substrate 5, 7 Auxiliary plate 11, 21, 31 Upper heater 12, 22, 32 Lower heater 13, 15, 23, 25, 33, 35 Air inlet 14, 16, 24, 26, 34, 36 Exhaust port 17, 27, 37 Transport rollers 18, 28, 38 Cooling unit

Continued front page    (72) Inventor Masanori Suzuki             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 4K050 AA02 BA07 BA17 CA13 CD30                       CF06 CF16 CG04                 4K055 AA06 HA02 HA11                 5E343 AA23 AA26 ER31 ER54 GG11

Claims (10)

[Claims] 1. A method in which one or more substrates provided with a functional film material are arranged on an auxiliary plate to form a unit to be heat-treated, and the plurality of units to be heat-treated are successively conveyed in one direction to perform heat treatment. In the cooling process of the heat treatment,
Each of the heat-treated units is housed in each of a plurality of heat-treatment chambers whose temperatures are gradually lowered in one direction, and is cooled or heated independently depending on the heat capacities of the auxiliary plate and the substrate. A soaking step of soaking each of the heat-treated units at a set temperature for each heat-treatment chamber while maintaining a predetermined amount of warpage per unit area within a predetermined range, and a plurality of heat-treated units in a plurality of heat-treatment chambers in order. A carrying-out step of sending out, a cooling medium supplying step of supplying a cooling medium to a predetermined heat treatment chamber to which the heat treatment target unit has been sent out, and a carrying-in step of sending the next heat treatment target unit into the predetermined heat treatment chamber after the cooling medium supply step And a heat treatment method using an auxiliary plate. 2. A warp amount Δδ (m per predetermined unit area)
⁻¹ ) is represented by the following formula and satisfies Δδ ≦ 0.028, The heat treatment method using an auxiliary plate according to claim 1. Δδ = [t {(α · ΔT) ⁻¹ +1}] · [1-cos
{(D ・ α ・ ΔT) ・ (2t) ^-1 }] ・ S ^-1 where t: thickness (m), α: coefficient of thermal expansion, ΔT: temperature difference (° C), D: typical length of substrate (M), S: area of the substrate (m ² ), and when the substrate is a quadrangle, D is a diagonal length (m) represented by D: (X ² + Y ² ) ^0.5 ,
X and Y are vertical and horizontal lengths (m) of the substrate, and S is S: X × Y.
Area (m ² ), and if the substrate is circular,
Let D be the diameter (m) and S be the area (m ² ) represented by S: 0.25πD ² . 3. The unit to be heat-treated is characterized in that the substantially central portion of the auxiliary plate is controlled or cooled from the auxiliary plate side in a state in which the cooling or heating capacity is higher or equivalent to that of the end portion. A heat treatment method using the auxiliary plate according to claim 1. 4. The unit to be heat-treated is characterized in that the substantially central portion of the auxiliary plate is controlled or cooled from the substrate side in a state in which the cooling or heating ability is higher or equivalent to that of the end portion. A heat treatment method using the auxiliary plate according to item 1. 5. The control according to the heat capacity of each of the auxiliary plate and the substrate is performed by cooling or heating from the auxiliary plate side and the substrate side respectively and independently controlling each cooling or heating. A heat treatment method using the auxiliary plate according to claim 1. 6. An air supply port for blowing a cooling gas and an exhaust port for exhausting the cooled cooling gas to the outside of the heat treatment chamber are provided, and the cooling gas is blown to the substantially central portion of the auxiliary plate and the substrate by the air supply port and the exhaust port. The heat treatment method using the auxiliary plate according to claim 5, wherein the heat treatment is performed. 7. The auxiliary plate according to claim 5, wherein a cooling unit for cooling by passing a cooling medium through the pipe is arranged, and the cooling unit cools substantially the central portion of the auxiliary plate and the substrate. Heat treatment method using. 8. The cooling gas is air, N ₂ , O ₂ , H ₂ O,
The heat treatment method using an auxiliary plate according to claim 6, wherein the heat treatment method is one selected from a single gas or a mixed gas of CO, CO ₂ , H ₂ , He, Ar, and Xe. 9. The cooling medium is a liquid containing water as a main component, or air, N ₂ , O ₂ , H ₂ O, CO, CO ₂ , H ₂ or H.
The heat treatment method using an auxiliary plate according to claim 7, wherein the heat treatment method is selected from a single gas or a mixed gas of e, Ar, and Xe. 10. The heat treatment method using an auxiliary plate according to claim 1, wherein the auxiliary plate has a smaller coefficient of thermal expansion than the substrate.