JP2806919B2 - Constant temperature bath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermostat for curing an adhesive or the like, and more particularly, to heating an electronic device element such as a semiconductor chip to a substrate, a lead frame or a package and then heating the adhesive to cure the adhesive. Related to thermostat.

[0002]

2. Description of the Related Art Conventionally, an adhesive or the like using a thermosetting resin such as an epoxy resin has to be cross-linked by applying heat or the like for a predetermined time in order to enhance the adhesiveness. As described above, a thermostat is usually used to cure the adhesive.

FIG. 9 is a cross-sectional view of a thermostat showing an example of the related art. This type of constant temperature bath is disclosed, for example, in Japanese Utility Model Laid-Open Publication No. 186234/1994 as a clean atmosphere heating device.
In this clean atmosphere heating apparatus, as shown in FIG. 9, a constant temperature bath 23 is separated into a double structure by a partition wall 28, and is disposed at a central portion so as to surround a clean chamber portion B of a high temperature clean environment and the clean chamber portion B. It comprises a gas cleaning section A and a circulation chamber C.

The gas filter 25 is provided between the gas cleaning section A and the clean chamber section B, and a circulation chamber C is formed below the partition wall 28.
A fan 26 rotated by a motor 27 between the gas cleaning section A and a heater 2 in the clean chamber section B.
4 and a second fan 20 are provided. Further, between the outlet of the clean chamber section B and the circulation chamber C, there is provided a damper 30 for opening and closing a valve body in the passage, and an intake port 29 on the circulation chamber C side near the damper 30. An exhaust port 21 is provided on the clean chamber section B side.

FIG. 10 is a diagram for explaining the operation of the constant temperature bath of FIG. 9 at the time of start. The operation of the thermostat in FIG. 9 at the start is as shown in FIG.
The intake port 29 and the exhaust port 21 are closed by the valve body of the damper 30,
A gas circulation path indicated by a broken line is formed. And fan 2
The gas that has been operated and is not heated passes through the gas filter 25.
, Passes through the clean chamber section B, passes through the circulation chamber C, is returned by the fan 26 again, and is sent to the gas filter 25 again. Thus, the gas in the clean chamber B is cleaned by circulating the gas in the thermostat 23.

FIG. 11 is a view for explaining the operation of the thermostatic chamber of FIG. 9 after cleaning the gas. After performing the above-described operation for a certain period of time, as shown in FIG. 11, the damper 30 is switched so that the intake port 29 communicates with the circulation chamber C and the exhaust port 21 communicates with the clean chamber section B. Then, for example, an inert gas is introduced from the intake port 29 and is blown by the fan 26 through the circulation chamber C. At this time, the rotation speed of the fan 26 is reduced so that the high-pressure inert gas does not enter the gas filter 25, the gas passes through the gas filter 25 little by little, is sent into the clean chamber part B, passes through the clean chamber part B, and is discharged through the exhaust port 21. To be discharged from

Next, the second fan 20 in the clean chamber section B is operated, and at the same time, the heater 24 is operated to circulate a clean gas only in the clean chamber section B as indicated by an arrow. Here, when the sample 31 is stored in the clean chamber section B, the gas generated from the sample 31 by the heated gas is also exhausted from the exhaust port 21 as shown by the dashed line. Note that the gas is characterized in that a less expensive nitrogen gas can be supplied to form a nitrogen gas atmosphere.

[0008]

In the above-mentioned conventional thermostat, the gas is heated at a low blowing pressure and then heated and circulated in the clean chamber, so that the heated gas does not pass directly through the gas filter. Although the life of the gas filter is extended, there is a problem that a long temperature rise time is required and the bake cycle time of the sample is prolonged.

In addition, there is no special cooling mechanism, and there is a disadvantage that the heater must be turned off and the fan 4 alone circulates through the clean chamber for cooling, and it takes a long time to lower the temperature. Further, there is a problem that the bake cycle time is lengthened.

Further, in order to purify the gas, an inert gas or the like is introduced and circulated at a low wind pressure, and the pressure inside the tank is low. Oxygen is mixed into the part, and these heavy oxygen molecules remain without being completely removed, and a sample such as a semiconductor element which is easily oxidized is oxidized by the residual oxygen, and a thick oxide film is formed on the semiconductor element, resulting in a defective product. There's a problem.

On the other hand, a large amount of gas generated from the sample to be baked is not exhausted, and when cooled, these gases solidify and re-attach to the sample itself, causing a great quality defect in the subsequent process. In addition, since these solidified particles are exhausted at a low wind pressure, the ability of attaching and removing the gas filter, which is an original function of the gas filter, is lost, and the particles adhere to the wall surface of the clean chamber. There is a problem that the coagulated matter attached to the wall surface evaporates by reheating and significantly impairs cleanliness.

Further, since there is no means for recognizing clogging of the filter, it is not possible to remove the coagulated material by further reducing the wind pressure and to remove the coagulated material by using the filter as it is when the time to replace the filter is lost. Will be encouraged.

Accordingly, it is an object of the present invention to provide a thermostatic bath in which gas generated from a sample, residual oxygen, etc. are completely discharged, the adhesive is cured in a clean inert gas atmosphere, and the curing cycle time is reduced. Is to do.

[0014]

Feature of the present invention SUMMARY OF THE INVENTION is positioned between the tank body sample by the partition wall is divided into a circulation chamber and the processing chamber to be contained, and the circulation chamber and the processing chamber A gas filter, a circulating inert gas supply system for supplying a circulating inert gas from the circulation chamber through the gas filter to the processing chamber by a fan ,
The gas filter is arranged and
Heating the inert gas for circulation sent through the first
Heater, an inert gas supply system for maintaining an internal pressure for supplying an inert gas to maintain the pressure in the tank body higher than the pressure of the outside air, and a cooling inert gas for cooling the inside of the tank body and cooling the inert gas supply system for supplying, prior to
An oxygen concentration meter for measuring the oxygen concentration in the processing chamber;
Read the pressure difference between the front and rear stages of the body filter
A differential pressure gauge for monitoring the clogging of the filter, and the supplied inert gas for circulation and the inert gas for maintaining the internal pressure.
Maintaining the pressure of the tank body to a constant and the acid in the processing chamber
A constant temperature bath including a first damper configured to control opening and closing of a valve body based on a detected amount of elemental concentration and to discharge an impurity gas in the processing chamber and a gas generated by the sample.

In addition, the circulation inert gas supply system is
It is desirable to have two heaters. Further, the first
Cover the end of the pipe that houses the valve element of the
Connecting the external duct and the valve element housed in the external duct.
It is desirable to have a second damper provided.

Another feature of the present invention is that the sample is separated by the partition wall.
A tank body divided into a processing chamber and a circulation chamber,
Gas filter arranged between the circulation chamber and the processing chamber
A fan provided in the circulation chamber;
Through the gas filter to the fan in the processing chamber
Inert gas for circulation in the tank that supplies more inert gas for circulation
A supply system, and scatteredly arranged in the circulation chamber;
Sent by the fan through the gas filter
A plurality of third heaters for heating the inert gas for circulation
To maintain the pressure in the tank body higher than the pressure of the outside air.
Supply inert gas to maintain the internal pressure.
A supply system and a cooling inert gas for cooling the inside of the tank body.
A cooling inert gas supply system for supplying heat, and the processing chamber
An oxygen concentration meter for measuring the oxygen concentration in the gas filter,
Read the pressure difference between the front and rear stages of the gas filter.
Differential pressure gauge for monitoring clogging, and the circulation inertness supplied
Tank tank made of neutral gas and inert gas for maintaining the internal pressure
Maintaining the body pressure constant and controlling the oxygen concentration in the processing chamber
The opening and closing of the valve body is controlled by the detected amount and the valve is in the processing chamber.
A third gas exhausting the impurity gas and the gas generated by the sample.
It is a thermostat provided with a vacuum chamber. In addition, the circulation inertness
It is desirable to provide a fourth heater in the gas supply system.
Further, an end of a pipe for storing the valve element of the third damper
The outer duct and the outer duct
And a fourth damper comprising a valve element to be accommodated.
desirable.

[0017]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a thermostat according to an embodiment of the present invention. As shown in FIG. 1, the thermostat 1 includes a processing chamber 1 a in which a sample 31 is stored by partitioning the inside of the main body of the thermostat 1 by a partition wall 18 and a circulation chamber 1 b,
A gas filter 3 provided between the circulation chamber 1b and the processing chamber 1a, a heater 2 provided between the gas filter 3 and the processing chamber 1a, and a heated inert gas or cooling introduced into the tank. A fan 4 driven by a motor 5 for circulating the inert gas in the tank through a gas filter 3 and a valve body for maintaining the pressure of the inert gas in the tank to be introduced slightly higher than the pressure outside the tank. And a damper a17 for controlling the opening and closing of.

A piping 19 provided with a flow meter 10 for supplying an inert gas heated by a heater 12 through an opening / closing valve 11 and adjusting a flow rate to the constant temperature bath 1.
a, a pipe 19b which supplies an inert gas through an opening / closing valve 9 to maintain the inside pressure of the tank slightly higher in order to prevent outside air from entering the inside of the tank, and is provided with a flow meter 8; An inert gas cooled to lower the temperature is supplied through the on-off valve 7 and a pipe 19c provided with the flow meter 6 is provided independently.

Further, a filter differential pressure gauge 13 for reading the difference between the back pressure of the fan 4 and the pressure of the processing chamber 1a to monitor the degree of clogging of the gas filter 3, and an oxygen for measuring the oxygen concentration in the processing chamber 1a. A concentration meter 14, a damper a17 for controlling the opening and closing of a valve body to keep the pressure of the processing chamber 1a constant by the supplied inert gas, and a pipe having a built-in valve body of the damper a17 with a gap formed in the pipe. And a damper b15 for accommodating the valve element in an external duct 16 which is connected to the valve.

A fan 4 for circulating an inert gas, for example, nitrogen gas, in the tank faces the gas filter 3 and is substantially the same size as the gas filter 3 so that the air pressure is uniform on the gas filter 3. Has been. With such a configuration, the temperature distribution of the nitrogen gas blown to the circulating gas filter 3 on the surface of the gas filter 3 is uniform, for example, ± 2.5 ° C at a temperature of 300 ° C. Obtained. This makes it possible to maintain uniform filter performance without locally heating the gas filter 3.

FIG. 2 is a diagram for explaining the operation of reducing the concentration of impurities and oxygen in the bath of the thermostatic bath of FIG. Next, an operation of lowering the oxygen concentration in the constant temperature bath will be described. First, the opening and closing valves 9 and 11 are opened, and the flow rate of the inert gas is measured by the flow meters 8 and 10, for example, at a pressure of 2 kg /
cm ² , set to 50 l / min and supplied into the tank. When the heater 2 and the heater 12 are turned on, the inert gas is heated and circulated through the gas filter 3 into the tank.
At this time, the dust generated from the sample 31 contained in the circulating inert gas is removed by the gas filter 3.
Further, the inert gas from the pipe 19b for maintaining the internal pressure is supplied so that the back pressure of the fan 4 does not decrease due to the rotation of the fan 4 and the pressure in the processing chamber 1a is maintained slightly higher than the external pressure of the tank. . On the other hand, the damper a17 is completely closed, and the damper a is diluted with the inert gas supplied to the processing chamber 1a until the indicated value of the oximeter 14 indicates, for example, the oxygen concentration in the tank is 0.1%. Keep closed.

Next, when the oxygen concentration in the tank is equal to or lower than a specified value and the pressure in the tank reaches a specified value (for example, 1.025 atm), the damper a17 is opened about halfway to discharge the inert gas. At this time, the piping
The pressure maintaining inert gas is supplied from b. In addition, air is drawn in from the gap of the external duct 16 so that air does not enter from the valve element of the damper a17 which has been opened halfway, and this air is passed through the valve element of the damper b15 together with the inert gas discharged from the damper a17. 16. Discharge outside. In this way, the inert gas heated by the heaters 12 and 2 is circulated, the pressure in the tank is controlled by opening and closing the valve of the damper a17, the temperature in the tank is raised to the set temperature, and the inert gas in the tank is increased. Completely replace with

As described above, by circulating the heated inert gas without decreasing the rotation speed of the fan 4, the temperature can be increased in a very short time. By the way, when the experiment was performed, although the temperature rise gradient was different, for example, 80 °
C to 150 ° C for about 7 minutes, 150 ° C to 220
° C in 16 minutes.

FIG. 3 is a diagram for explaining the baking operation in the thermostatic chamber of FIG. Next, the baking operation when the temperature in the thermostat reaches a predetermined temperature and the oxygen concentration becomes a specified value or less will be described. First, as described above, a heated inert gas for circulating and an inert gas for maintaining a pressure are mixed with, for example, an inner tank having a capacity of 0.216.
Pressure of 2kg / cm ² , 5 in cubic meter tank
Supply about 0 l / min. In this state, the sample 31 is baked, and even the gas dust generated from the sample 31 is removed by the gas filter 3, and the gas from which the dust is removed is discharged from the half-open damper a17 along with the inert gas. Is done.

The gas discharged from the damper a17 is discharged to the outside of the external duct 16 together with the air entering through the gap of the external duct 16. Further, the oxygen contained in the generated gas from the sample 31 and the inert gas supplied is measured by the oxygen concentration meter 1.
When the reading of 4 becomes equal to or more than the specified value, the damper a is closed and diluted with the circulating inert gas until the oxygen concentration in the tank becomes equal to or less than the specified value. When the pressure in the tank becomes lower than the specified value, the valve body of the damper a is opened halfway, and the generated gas containing oxygen in the tank is discharged from the external duct 16 together with the inert gas.

FIG. 4 is a diagram for explaining the operation of lowering the temperature in the constant temperature bath of FIG. Next, when the above-described baking operation is completed, the heater 2 and the heater 12 are turned off.
ff, the opening and closing valve 7 is opened, the flow meter 6 is adjusted, and the cooled inert gas is supplied into the tank at the above-mentioned flow rate. At this time, the inert gas for circulation in the tank and for maintaining the internal pressure is also supplied into the tank at the above-mentioned flow rate. Further, the valve body of the damper a17 is fully opened to discharge the gas containing oxygen generated in the tank. As a result, the temperature in the bath returned to room temperature much earlier than that of natural cooling, and the solidified product gas generated
1 and does not adhere to the inner wall of the tank.

FIG. 5 is a sectional view of a thermostat according to another embodiment of the present invention. As shown in FIG. 5, this thermostat is different from the thermostat in the above-described embodiment in that the heater 2a is disposed in the circulation chamber, and the thermostat rotates in the circulation chamber formed by the partition wall 18 and the inner wall of the inner tank. A relatively small fan 4a is arranged so that the supplied inert gas is pressure-fed to the gas filter 3 via the heater 2a in the circulation chamber. Similar to the thermostat in the above-described embodiment, the thermostat includes other inert gas supply systems for circulation in the tank, an inert gas supply system for maintaining the internal pressure, and an inert gas supply system for cooling.

As described above, by indirectly sending the pressure of the inert gas to the gas filter 3 via the heater 2a, the deterioration rate is reduced as compared with the above-described gas filter, and the gas filter 3 needs to be replaced once a year. The number was 0.7 times, and the life was prolonged.

FIG. 6 is a diagram for explaining the operation of lowering the oxygen concentration in the constant temperature bath of FIG. The operation of lowering the oxygen concentration in the bath in this constant temperature bath is to raise the temperature in the bath to a set temperature while lowering the oxygen concentration in the bath, as described with reference to FIG. At this time, the flow of the inert gas, the flow of the gas generated from the sample 31, and the flow of the air in the external duct 16 are shown in FIG.
As shown in FIG. 2, the behavior is the same as in FIG.

FIG. 7 is a diagram for explaining the baking operation in the constant temperature bath of FIG. The baking operation of the sample when the temperature in the thermostat reaches the predetermined temperature and the oxygen concentration becomes equal to or lower than the specified value is the same as described with reference to FIG. For example, if the inner tank capacity is 0.3 cubic meters, the supply amounts of the inert gas for circulating in the tank and the inert gas for securing the internal pressure are always 2 kg /
cm ₂ , 120 l / min, the damper a 17 was opened halfway, circulated, and the sample 31 was baked.
At this time, the flow of the inert gas, the flow of the gas generated from the sample 31, and the flow of the air in the external duct 16 behave in the same manner as in FIG. 3, as shown in FIG. Note that, for example, if the capacity of the heater 2a is MAX 5.8 KW or more, the set temperature can be maintained even if the heater 12 for heating the inert gas is turned off.

FIG. 8 is a diagram for explaining the operation of lowering the temperature in the constant temperature bath of FIG. Next, when the above-described baking operation is completed, as described with reference to FIG. 4, the heater 12 is turned off, the open / close valve 7 is opened, the flow meter 6 is adjusted, and the cooled inert gas is supplied into the tank at the above-described flow rate. I do. At this time, the inert gas for circulation in the tank and for maintaining the internal pressure is also supplied into the tank at the above-mentioned flow rate. Also, the damper a17
Is fully opened to exhaust gas containing oxygen generated in the tank and cool the inside of the tank. At this time, the flow of the inert gas, the flow of the generated gas from the sample 31, and the flow of the air in the external duct 16 behave as shown in FIG.

[0033]

As described above, the present invention measures the oxygen concentration in the inert gas supply system for maintaining the internal pressure and the processing chamber in the tank so that the pressure inside the tank is maintained higher than the pressure outside the tank. By installing an oxygen concentration meter and circulating an inert gas through a gas filter, impurities and oxygen in the tank can be completely removed without air entrainment or leakage from outside the tank to obtain a clean state. Therefore, even a sample that is easily oxidized can be baked without being oxidized, and the yield of quality is improved.

A heater is provided in the supply path of the circulating inert gas to supply the inert gas while heating it. When the inside of the tank is cooled, the cooled inert gas is supplied. By shortening the heating time and the cooling time, the bake cycle time is shortened and the productivity is improved.

Further, an oxygen concentration meter for measuring the oxygen concentration in the tank and a damper for automatically maintaining the pressure in the tank and discharging an inert gas containing oxygen and impurities are provided to reduce the rotation speed of the fan. By agitating the inside of the tank and completely removing the coagulated particles contained in the gas generated from the sample in the tank by the gas filter, the generated gas does not re-adhere to the sample or adhere to the inner wall of the tank. This has the effect of reducing the time required for improving the yield and maintaining the thermostat.

On the other hand, by providing a filter pressure gauge for monitoring the degree of clogging of the gas filter by reading the pressure difference between the upstream and downstream stages of the gas filter, it is possible to ascertain the replacement time of the gas filter and to maintain normal operation at all times. This has the effect of increasing the operation rate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thermostat in one embodiment of the present invention.

FIG. 2 is a diagram for explaining an operation of reducing the concentration of impurities and oxygen in the bath of the thermostatic bath in FIG.

FIG. 3 is a diagram for explaining a baking operation in the constant temperature bath of FIG. 1;

FIG. 4 is a view for explaining an operation of lowering the temperature in the bath of the thermostatic bath in FIG. 1;

FIG. 5 is a cross-sectional view of a thermostat in another embodiment of the present invention.

FIG. 6 is a diagram for explaining an operation of reducing the oxygen concentration in the constant temperature bath of FIG. 5;

FIG. 7 is a view for explaining a baking operation in the constant temperature bath of FIG. 5;

FIG. 8 is a diagram for explaining an operation of lowering the temperature in the constant temperature bath of FIG.

FIG. 9 is a cross-sectional view of a thermostat showing an example of the related art.

FIG. 10 is a diagram for explaining an operation at the time of starting the thermostatic bath in FIG. 9;

FIG. 11 is a diagram for explaining the operation of the thermostat in FIG. 9 after cleaning of gas.

[Explanation of symbols]

 1,23 thermostat 1a processing chamber 1b, C circulation chamber 2,2a, 12,24 heater 3,25 gas filter 4,4a, 26 fan 5,27 motor 6,8,10 flow meter 7,9,11 opening / closing valve 13 Differential pressure gauge for filter 14 Oxygen concentration meter 15 Damper b 16 External duct 17 Damper a 18, 28 Partition wall 19a, 19b, 19c Pipe 20 Second fan 21 Exhaust port 29 Inlet port 30 Damper 31 Sample

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-4456 (JP, A) JP-A-1-247072 (JP, A) JP-A-2-271287 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) F26B 9/06 F26B 25/06

Claims (6)

(57) [Claims] 1. A and tank body in which the sample is partitioned into the circulation chamber and the processing chamber to be accommodated by the partition walls, and gas filter disposed between the processing chamber and the circulation chamber, the gas from the circulation chamber and the inert gas supply system for tank to circulate and supply the circulating inert gas by the fan into the processing chamber through the filter, the fan while being disposed in the processing chamber
A first heater for heating the circulation inert gas sent through the gas filter, and an internal pressure supply for supplying an inert gas to maintain the pressure in the tank body higher than the pressure of the outside air. An inert gas supply system, a cooling inert gas supply system for supplying a cooling inert gas for cooling the inside of the tank body, and measuring an oxygen concentration in the processing chamber.
Oxygen meter and the pressure difference between the first and second stages of the gas filter
Pressure gauge that reads the gas and monitors the clogging of the gas filter
When, maintaining the pressure of the tank body by the circulation the inert gas and the internal pressure inert gas maintained supplied to the constant
Opening and closing of the valve according to the detected amount of oxygen concentration in the processing chamber
And a first damper configured to discharge the impurity gas in the processing chamber and the gas generated by the sample. 2. A second inert gas supply system for circulation,
The constant temperature bath according to claim 1, further comprising a heater . 3. A pipe for accommodating a valve body of the first damper.
And an external duct for connecting the ends of the
The constant temperature bath according to claim 1 or 2, further comprising a second damper including a valve element housed in the chamber. 4. A processing chamber in which a sample is stored by a partition wall.
A tank body partitioned into a circulation chamber, the circulation chamber and the treatment
A gas filter arranged between the circulation chamber and the circulation chamber;
A fan provided, and the gas filter from the circulation chamber.
Through the fan into the processing chamber through the inert gas for circulation.
An inert gas supply system for circulation in a tank for supplying heat,
It is scatteredly arranged in the annulus and by the fan
The inert gas for circulation sent through the gas filter;
A plurality of third heaters for heating the bath, and a pressure inside the tank body.
Inert gas to maintain power above ambient pressure
An inert gas supply system for maintaining the internal pressure to be supplied, and the tank body
Cooling inert gas that supplies a cooling inert gas to cool the inside
The active gas supply system and the oxygen concentration in the processing chamber are measured.
Oxygen meter, and pressures before and after the gas filter
Differential pressure to read the difference and monitor the clogging of the gas filter
And the supplied inert gas for circulation and the internal pressure
Maintains a constant pressure in the tank body with a maintenance inert gas
And opening of the valve body based on the detected amount of oxygen concentration in the processing chamber.
Closure is controlled and impurity gas and the sample in the processing chamber are closed.
Constant temperature bath you anda third dampers for discharging the generated gas. 5. A fourth inert gas supply system for circulation is provided with a fourth inert gas.
The constant temperature bath according to claim 4, further comprising a heater . 6. A pipe for storing a valve element of the third damper.
And an external duct for connecting the ends of the
The constant temperature bath according to claim 4 or 5 , further comprising a fourth damper including a valve element housed in the container .