JPS6219434A - Controlling system of temperature and pressure in vacuum press - Google Patents

Abstract

PURPOSE:To control the temperature or pressure in a press chamber in accordance with a temperature approximate to the actual temperature of laminated resin boards by a method wherein the temperature of mirror plates contacting with the resin board, platens and the like are detected at a plurality of locations so that the temperature or pressure in the press chamber is changed over to the following step after the temperature of the resin board of the worst condition reaches the set temperature. CONSTITUTION:The temperatures of resin boards 13 are detected by thermocouples provided in mirror plates 15. The temperature detected by each thermocouple 25 is converted by each temperature transducer 28 to a voltage signal in order to be compared with the set temperature signal outputted from a main controller at each voltage comparator 29. The temperature in a press chamber 1 is kept constant until the temperatures of all the mirror plates 15 and consequently the temperatures of all the resin boards 13 reach the set value. When the temperatures of all the mirror plates 15 reach the set value, an AND circuit 30 outputs a signal in order for the main controller 27 to generate a heater control signal so as to actuate a heater power circuit 8 in response to the following controlling step.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a vacuum press that stacks a plurality of resin plates, evacuates the surrounding area, and heats and pressurizes the resin plates to laminate the resin plates. In particular, it relates to a control method for controlling the heating timing and pressurizing timing.

(Prior Art) For example, in printed wiring boards, in order to further increase the degree of integration of wiring, it is required to laminate multiple layers. When manufacturing such a multilayer printed wiring board, an appropriate number of prepregs are usually stacked on both sides of a printed wiring board that has wiring patterns formed on both sides.

Further, copper-clad resin plates serving as outer layers are stacked on both sides of the prepreg, and heated and pressurized to melt and thermoset the prepreg, thereby forming a multilayer laminate. By etching the copper foils on both sides of the laminate thus obtained into a predetermined pattern, a multilayer printed wiring board can be obtained.

Conventionally, a hydraulic press has generally been used to heat and press a plurality of resin plates stacked in this manner. In that case, the stacked resin plates are sandwiched between the pressers of a hydraulic press, and pressure is applied using fluid pressure while heating the pressers. Then, the prepreg of the resin plates is heated and gelled by the heat applied through the presser, and is thermally hardened over the course of one hour, thereby bonding the resin plates to each other.

However, in such hydraulic presses,
Because heat is dissipated from the sides of the stacked resin plates,
There is a problem in that the temperature of the intermediate resin plate and the upper and lower resin plates differ. There is also the problem that the resin impregnated into the prepreg flows out from the sides.

Therefore, attempts have been made to laminate such resin plates by vacuum pressing. This vacuum press seals the stacked photoresin plates with a backing sheet, connects the inside to a vacuum pump to create a vacuum, and applies high-temperature, high-pressure gas to the outer surface of the backing sheet to completely seal the resin plates. It is heated and pressurized from the periphery. According to such a vacuum press! l
The air between the stacked resin plates and the air contained in the resin of the prepreg is pulled out by a vacuum pump, so it does not remain as voids in the product, and since it is heated from all around, The temperature of the stacked resin plates becomes almost uniform throughout. Furthermore, since the resin will not flow out, the thickness of the product will be uniform.

When forming a laminate using such a vacuum press, 1. Normally, a plurality of resin plates forming one laminate are stacked to form one set of resin plates, and multiple sets of the resin plates are stacked. A plurality of books are stacked one on top of the other with metal mirror plates sandwiched between them, and the books are placed on a platen. Then, the platens with the books placed on them are placed in a sealed press chamber at multiple levels, and a high temperature, high pressure inert gas such as nitrogen gas or carbon dioxide gas is introduced into the press chamber to simultaneously print a large number of books. laminates are formed.

(Problems to be Solved by the Invention) By the way, in such a vacuum press, the temperature and pressure inside the press chamber change according to predetermined steps depending on the properties of the resin used for the resin plate. For example, during heating, when the prepreg resin reaches a temperature just before it gels, the temperature is held constant, and the temperature is raised again after a predetermined period of time has elapsed. By doing this, the internal air is completely removed before the resin gels, and no voids remain in the product. Also, once the curing temperature is reached, it is held constant at that temperature and more pressure is applied.
Make sure each resin plate is completely adhered.

Conventionally, this temperature and pressure control was performed based only on the temperature within the press chamber. however,
The temperature inside the press chamber does not match the temperature of the resin plate, and it is inevitable that temperature unevenness will occur within the press chamber, so even if the temperature near one resin plate reaches the set value, The temperature around the resin plate may not reach that value. Also, according to the vacuum press,
Although the stacked resin plates are heated almost uniformly from all around the circumference, the thermal conductivity of the resin plates is low, so even if the surrounding temperature reaches the set value, the temperature at the center will remain at that temperature. Sometimes the value has not been reached. If the actual temperature of each resin plate can be detected, the temperature and pressure inside the press chamber can be controlled based on that temperature, and optimal control can be performed. This is not possible since temperature sensors such as thermocouples cannot be attached to the plate. For this reason, in the conventional method, the temperature or pressure inside the press chamber may advance to the next step before the temperature of the resin plate reaches a predetermined value, resulting in a product of poor quality. there were.

The present invention was developed in view of these problems, and its main purpose is to ensure that the temperature or pressure inside the press chamber in a vacuum press is close to the actual temperature of the resin plates to be laminated. The goal is to ensure that the system is controlled accordingly.

Another object of the present invention is to allow temperature or pressure control to proceed to the next step after all resin plates have reached the same temperature condition.

(Means for Solving the Problems) In order to achieve this object, the present invention measures the temperature of the resin plates to be laminated at different positions inside the press chamber. The temperature or pressure inside the press chamber is indirectly detected by parts where heat conduction occurs, such as a mirror plate or platen, and when the temperature reaches a set value, the temperature or pressure inside the press chamber is advanced to the next step. .

(Function) By detecting the temperature of the mirror plate, platen, etc. in contact with the resin plate in this manner, the detected temperature becomes close to the actual temperature of the resin plate. Furthermore, by detecting the temperature at a plurality of locations, the temperature of the resin plate at the location with the worst conditions can be detected. After the resin plate with the worst conditions reaches the set temperature, the temperature or pressure inside the press chamber is switched to the next step, so all the resin plates are kept at a constant temperature and uniform quality is achieved. The product will be available.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

In the drawings, FIG. 1 is a circuit diagram showing an embodiment of a temperature control system in a vacuum press according to the present invention, and FIG. 2 is a system diagram of an apparatus used in the vacuum press.

As shown in Figure 2, the vacuum press includes a
A press chamber l having a pressure-resistant structure that can be opened and closed by la is used. High-pressure nitrogen gas or an inert gas such as carbon dioxide gas is introduced into this sealed press chamber 1 from a gas tank 2. and,
The pressure inside the press chamber l is controlled by opening and closing a solenoid valve 3 provided in the gas passage from the tank 2 or a solenoid valve 5 provided in the exhaust passage opened to the atmosphere through the silencer 4. It has become.

A heater 6 and a cooler 7 are provided inside the press chamber 1 to heat or cool the gas inside. A voltage controlled by a heater power circuit 8 is applied to the heater 6 . Also, cooler 7
, the cooling water cooled by the cooling tower 9 is guided through a pump 10 and a solenoid valve 11. A blower 12 is provided at the back of the press chamber 1 to circulate gas heated or cooled by the heater 6 or the cooler 7 within the press chamber 1.

Inside the press chamber 1, a space is provided for accommodating the resin plates to be laminated. When manufacturing a multilayer printed wiring board, the resin board is composed of an inner printed wiring board with wiring patterns printed on both sides, a prepreg, and a copper-clad resin board as an outer layer. 1st
As shown in the figure, these resin plates 13°13,
. . . is a book 14 by stacking several sets together, stacking a plurality of books 14 with a metal mirror plate 15 in between, and fixing this on a metal platen 16. dispersion plate) 17, and a large number of resin plates 13, 13. ... so that it can be accumulated. The resin plates 13, 13. ...The whole is covered with a cotton-like cloth and a backing sheet 18 such as silicone resin,
Seal tape 19 around the entire periphery of the backing sheet 18
It is airtightly adhered to the platen 16 by the following steps.

In the press chamber 1, the platen 16 on which the multilayer resin plates 13, 13°, etc., whose entire surface is hermetically sealed in this way is mounted, is accommodated in multiple stages, stacked, or in parallel. It has become. Each platen 16 is provided with a piping 20 that communicates through the dispersion plate 17 with an internal space covered by a backing sheet 18. As shown in FIG. 2, this piping 20 is connected to a vacuum piping that communicates with a vacuum pump 23 within the press chamber 1 via a solenoid valve 21 and a vacuum chamber 22.

As shown in FIG. 1, a reference thermocouple 24 is provided within the press chamber 1 to detect the gas temperature inside the press chamber. In addition, books 14, 14° stacked on the platen 16...mirror plates 15, 1 inserted between
5. ... are provided with thermocouples 25, 25, ... at their centers, respectively. The reference thermocouple 24 is connected to a main controller 27 via a temperature converter 26. In addition, other thermocouples 25, 25 . . . . are temperature converters 28,
Voltage comparator 29°29,... via 2B,...
It is connected to the. These voltage comparison amounts 29 , 29 , .
A set temperature signal is introduced from the main controller 27. Each voltage comparator 29, 29. The output signals of the AND circuit 30 are led to the AND circuit 30, and the output signals of the AND circuit 30 are led to the main controller 27.

The main controller 27 receives the signal from the temperature converter 26 and the signal from the AND circuit 30 and applies a heater adjustment signal to the heater power circuit 8.
When the signal from the heater 6 reaches a predetermined level, the heater 6
is stopped, the gas temperature in the press chamber 1 is kept constant, and when a signal from the AND circuit 30 is received, the amount of heat generated by the heater 6 is controlled according to the next control step.

When forming a laminate using the vacuum press system configured in this way, the book 14 consisting of resin plates 13, 13, . . . stacked on the platen 16 and covered with a backing sheet 18 as described above. 14
．． ... into the press chamber 1, and each platen 16
Connect the piping 20 provided in the vacuum pump 23 to the vacuum pump 23.

(backing sea) 18 is sucked. As a result, the area around the book 14 is evacuated, and the resin plates 13, 13 .
...The air between them is sucked out.

In this state, the solenoid valve 3 of the pressure supply system is opened, and the high pressure gas in the tank z is introduced into the press chamber l. When the pressure inside the press chamber l reaches a predetermined value, the solenoid valve 3 closes,
The pressure is kept constant. Meanwhile, the operation of the heater 6 is started during this time. As a result, the gas temperature within the press chamber 1 increases.

The temperature within the press chamber I is tracked by a reference thermocouple 24, converted by a temperature converter 26 into a voltage signal proportional to the temperature, and input to the main controller 27. When the temperature inside the press chamber l reaches the set value set in the main controller 27, the main controller 27 outputs a heater stop signal to the heater power circuit 8. This causes the heater 6 to stop,
The temperature within the press chamber I is kept constant. This set temperature is set to a temperature immediately before the resin gels.

When the temperature inside the press chamber 1 rises in this way, the resin plates 13, 13, . . . housed therein are heated. However, since the resin plate 13 has a low thermal conductivity, its temperature rises slowly. Moreover, each resin plate 13, 13. There will be variations in the temperature of... This resin plate 13°13...
The temperature of * is indirectly detected by the thermocouple 25 provided on the mirror plate 15. In this case, since the mirror plate 15 is made of metal, the temperature will be different from the actual temperature of the resin plate 13, but since heat conduction occurs between the mirror plate 15 and the resin plate 13, the temperature of the mirror plate 15 will be different from the actual temperature of the resin plate 13. The temperature of the face plate 15 is similar to the temperature of the resin plate 13.

The temperature detected by each thermocouple 25 , 25 , . . . is converted into a voltage signal by a temperature converter 28 , 2g , . It is compared with the output set temperature signal. When the temperature of the mirror plate 15 reaches the set temperature, the comparators 29 , 29 .

An output signal is emitted from... At this time, the resin plate 13
．． 13. . . . due to temperature variations between the other mirror plates 15, 15 . The temperature of ... may not reach the set temperature. In that case, since no signal is output from the AND circuit 30, the state remains as it is. In this way, all the mirror plates 15, 15. ..., and therefore all the resin plates 13, 13. The temperature inside the press chamber 1 is kept constant until the temperatures of . . . reach the set values.

All mirror plates 15, 15. When the temperature of... reaches the set value, a signal is output from the AND circuit 30. Thereby, the main controller 27 generates a heater adjustment signal to cause the heater power circuit 8 to operate according to the next control step. The control step is, for example, a pattern in which the temperature inside the press chamber 1 is further maintained at a constant temperature for a certain period of time, and then the temperature is raised to the cure temperature. By doing this, while the temperature inside the press chamber l is kept constant, that is, while the temperature of the resin plates 13, 13, . . . The air contained in it will now be completely sucked out. And each resin plate 13.13.
When all the temperatures of ... are almost the same, the temperature will be raised to the curing temperature.

Therefore, the curing time until the resin melts and completely hardens can also be accurately secured.

Further, at an appropriate time during this period, the electromagnetic valve 3 of the pressure supply system is opened, and the pressure within the press chamber 1 is increased according to predetermined steps. In this way, while the resin is in a molten state, sufficient pressure is applied between the resin plates 13, 13, . . . to ensure bonding between them.

When the curing time has elapsed, the solenoid valve 11 of the cooling system
When the press chamber 1 is opened, the pump 10 is activated, cooling water is supplied to the cooler 7, and the gas in the press chamber 1 is cooled. Further, the solenoid valve 5 of the exhaust system opens, and the gas in the press chamber 1 is released into the atmosphere through the silencer 4. In this way, the product molded in the press chamber I can be removed.

FIG. 3 shows the temperature change inside the press chamber 1 during the above press cycle. As shown by broken lines in this figure, each mirror plate 15, 15 . ..., that is, the temperature of each resin plate 13.13. The temperature of the resin plates 13, 13 varies greatly, especially at the beginning of heating.
.

...There will be large variations depending on the temperature, and it will be necessary to take a long time for curing, but once the temperature is equalized at the set temperature as described above, the temperature will change in the same way after that, and the curing time will be kept to a minimum. You will be able to do this.

In this way, in this embodiment, the resin plates 13, 13 . . . are stacked in multiple layers on one platen 16.・
...but the temperature becomes almost uniform throughout, making it possible to obtain a homogeneous product. A plurality of platens 16, 16. ...
Resin plate on top 13.13. . . , if similar thermocouples 25° 25, . . . . can be made to have a uniform temperature. If the number of resin plates 13, 13°, etc. stacked on each platen 16 is small, a thermocouple 25 is attached to each platen 16 as shown in FIG. 1
6, the resin plates 13, 13. It is also possible to indirectly detect the temperature of... In this way, the temperature difference between each platen 16 can be eliminated.

FIG. 5 is a circuit diagram showing an embodiment of a pressure control method in a vacuum press according to the present invention.

In this embodiment, the configuration is similar to that in FIGS. 1 to 4. However, in this case, AND circuit 3
The zero output is directed to the pressure controller 31. This pressure controller 31 includes an AND circuit 3
When a zero signal is received, the solenoid valve 3 of the pressure supply system is opened and the pressure in the press chamber 1 is controlled according to the next predetermined control step.

In this case, the main controller 27 connects each voltage comparator 29, 29 . The set temperature signal guided by . . . is a signal corresponding to the curing temperature, for example. By doing this, as shown in FIG.
3,13. Maximum pressure is applied after all... have reached the curing temperature. Therefore, large pressure is not applied before some of the resin plates 13 reach the curing temperature, and all the resin plates 13.13. ...
are bonded in a uniform state, resulting in a homogeneous product.

When such pressure control is performed, more direct temperature detection of the resin plates 13, 13, . . . is desired than when temperature control is performed. therefore.

In this case, as shown in FIG.
A dummy resin plate 13' is inserted between the resin plates 13 and 13, where the temperature rise is expected to be the slowest, in the middle between 5.15 and 13.15, and the temperature of the dummy resin plate 13' is detected. The dummy resin plate f3' is made of, for example, a cured resin of the same material as the prepreg resin, or a prepreg sandwiched between copper-clad resin plates, and the thermocouple 25 is embedded inside the dummy resin plate f3'.

By using such a dummy resin plate 13',
A temperature approximately equal to that of the resin plate 13 in the vicinity is detected. Therefore, the pressure control can be performed at extremely accurate times. Of course, such a dummy resin plate 13' can also be used in a temperature control system as shown in FIG.

In the above embodiments, thermocouples 24 and 25 are used as the temperature detection means, but the temperature detection means is not limited to this, and any suitable temperature sensor may be used.

(Effects of the Invention) As is clear from the above description, according to the present invention, the temperatures of a plurality of resin plates installed at different positions in a press chamber are each indirectly detected, and all of the temperatures are set. When the temperature or pressure within the press chamber reaches the same value, the temperature or pressure in the press chamber is changed to the next step, so even if there are differences in the heating atmosphere of each resin plate, the temperature or pressure in the press chamber is changed after they reach the same temperature. , heated or pressurized under the same conditions. Therefore, it is possible to simultaneously obtain a large number of laminates of constant quality.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the temperature control method in a vacuum press according to the present invention, FIG. 2 is a system diagram of an apparatus used in the vacuum press, and FIG. FIG. 4 is an explanatory diagram of essential parts showing another embodiment of the temperature control method according to the present invention, and FIG. 5 is an illustration of an embodiment of the pressure control method in a vacuum press according to the present invention. FIG. 6 is a characteristic curve diagram of the operation obtained by the pressure control method, and FIG. 7 is an explanatory diagram showing an example of temperature detection means particularly suitable for the pressure control method. l... Press chamber 2... Tank 3... Solenoid valve 6... Heater 8... Heater power circuit 13... Resin plate 13'... Dummy resin plate 14... Book 15. ...Mirror plate 16...
・Platen 18...Backing sheet 23...Vacuum pump 24.25...Thermocouple 27...Main controller 31...Pressure controller Patent applicant Japan Steel Works Co., Ltd. Agent Patent attorney Mori Shimohan Figure 6 Figure 7 Procedural correction tooth (voluntary) August 8, 1985 Director General of the Patent Office Michibe Uga 1, Indication of the case 1985 Patent Application No. 158428 2, Name of the invention Temperature in a vacuum press and Pressure Control Method 3, Relationship with the Amendment Case Applicant (421) Japan Steel Works, Ltd. 4, Agent tOS Address Room 1102, Studio Toranomon, 3-18-12 Toranomon, Minato-ku, Tokyo Claims column 1 Detailed description of the invention column of the specification subject to the 50 amendment;
and Brief description of drawings column 0m direction 6, Contents of amendment (1) The scope of claims is amended as shown in the attached sheet. (2) The 11 sets of resin plates on page 6, lines 15 to 19 of the specification are placed on the platen. ”
The statement ``Make one set of boards, stack multiple boards with a metal mirror plate between each set to make one book, and place it on a platen.'' (3) The statement ``in a place with the worst conditions'' on page 1 O, lines 6-7 of the specification is amended to ``in a place with the worst conditions.'' (4) On page 12, lines 11 to 13 of the specification, the statement ``Several sets are stacked together...'' has been changed to ``Pile one set together to form the board 14. A plurality of boards 14 are stacked with a metal mirror plate 15 sandwiched between them.'' (5) The description “Book 14” on page 13, line 18 of the specification is amended to “Board 14J.” (6) The description “Book 14J” on page 15, lines 6 and 10 of the specification is amended to “BOARD 14J.” , respectively “Board 14
” he corrected. (7) [tIj on page 22, lines 10 to 12 of the specification]
, between the face plates 15, 15...dummy resin plate 13'
[Resin plate 13.13 where the temperature rise is expected to be the slowest.
In between, a dummy resin plate 13' is inserted in place of the mirror plate 15, and the correction is made as follows. (8) The statement "14...Book" on page 25, line 5 of the specification is amended to read "14...Board." (9) All drawings shall be amended as shown in the attached drawings. 7. List of attached documents (1) Attachment (2) Attachment to drawings 2. Claims (1) Plural resin plates 13, 13. A plurality of Bode 4 stacked with . By doing so, the resin plates 13,1
3. In a vacuum press in which a laminate is formed by bonding . . . to each other: A temperature control method for a vacuum press, which indirectly detects temperature through the parts being processed, and when the temperature reaches a certain set value, changes the temperature in the press chamber 1 according to the following steps. (2) The temperature of the mirror plate 15 inserted between the stacked resin plates 13 and 13 is detected as the temperature of the resin plate 13. Temperature control method in vacuum press. (3) As the temperature of the resin plate 13. 2. The temperature control method in a vacuum press according to claim 1, wherein the temperature of the platen 16 on which the second platen 14 is placed is detected. A plurality of resin boards 13, 13... (0) are placed in a sealed press chamber 1, the area around the board 14 is evacuated, and the temperature inside the press chamber 1 is reduced. and by changing the pressure according to predetermined steps, the resin plates 13,1
3. In a vacuum press in which a laminate is formed by bonding ... to each other; A pressure control method in a vacuum press, wherein the pressure in the press chamber is indirectly detected through the parts being processed, and when the temperature reaches a certain set value, the pressure in the press chamber is changed according to the following steps. (5) As the temperature of the resin plate 13, the temperature of a dummy resin plate 13' formed of the same material as the resin plate 13 and inserted between appropriate resin plates 13 and 13 is detected. A pressure control system in a vacuum press according to claim 4.

Claims (5)

[Claims] (1) A plurality of books 14 made by stacking a plurality of resin plates 13, 13, . and by changing the pressure according to predetermined steps, the resin plates 13, 1
3. In a vacuum press in which a laminate is formed by bonding the resin plates 13 to each other; A temperature control method in a vacuum press, which is configured to indirectly detect the temperature through the part where conduction takes place, and when the temperature reaches a certain set value, the temperature in the press chamber 1 is changed according to the following steps. . (2) The temperature of the resin plate 13 is determined by detecting the temperature of a mirror plate 15 inserted between the stacked resin plates 13, 13. Temperature control method in vacuum press. (3) The temperature of the platen 16 on which the book 14 is placed is detected as the temperature of the resin plate 13.
Temperature control method in the vacuum press described in section. (4) A plurality of books 14 made up of a plurality of stacked resin plates 13, 13, . and by changing the pressure according to predetermined steps, the resin plates 13, 1
3. In a vacuum press in which a laminate is formed by bonding the resin plates 13 to each other; A pressure control method in a vacuum press, which is indirectly detected through the part where conduction takes place, and when the temperature reaches a certain set value, the pressure in the press chamber 1 is changed according to the following steps. . (5) As the temperature of the resin plate 13, the temperature of a dummy resin plate 13' formed of the same material as the resin plate 13 and inserted between appropriate resin plates 13, 13 is detected. A pressure control method in a vacuum press according to claim 4.