JP2002361500A - Thermal press device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal press device for maintaining the pressure equalization property of pressurization when forming with a thermal press and for manufacturing a high-quality circuit board. SOLUTION: By using a thermal press device 1 which is constituted in a contact state in the order of an upper fixed board 5, an upper heat insulating plate 7a, an upper cushoning material 8a and an upper heating board 3a from above and in a contact state in the order of a hydraulic cylinder 4, a lower movable board 6, a lower heat insulating plate 7b, a lower cushoning material 8b and a lower heating board 3b from below, laminated constituents 2 placed on the lower heating board 3b are pressurized into the laminated constituents of circuit boards with the upper and lower heating boards 3a, 3b by upward driving the lower heating board 3b with the hydraulic cylinder 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot press used for manufacturing a circuit board.

[0002]

2. Description of the Related Art With the recent miniaturization and high-density of electronic equipment, circuit boards on which electronic components are mounted have been changed from conventional single-sided boards to double-sided, multi-layer boards, and more circuits have been mounted on the boards. A high-density circuit board that can be integrated is being developed.

[0003] With the miniaturization of circuit design rules,
It has become necessary to reduce the thickness of a metal foil for forming a circuit to facilitate formation of a fine wiring pattern, and to reduce the weight of a circuit board with application to portable equipment.

In particular, in the case of a multilayer circuit board, circuit design rules are finer than those of a conventional circuit board, and processing techniques for forming a finer circuit, alignment of an interlayer circuit or through holes and via holes are required. The development of technology for connecting layers with a fine connection pitch has been continued.

Hereinafter, a method of manufacturing a multilayer circuit board using a conventional heat press device will be described.

FIGS. 3A and 3B are schematic views schematically showing a multi-layer circuit board manufacturing process using a conventional hot press apparatus. FIG. 3A shows a laminated component forming process, FIG. 3B shows a hot press process, and FIG. 3 shows a laminated component disassembly step.

First, the laminated component forming step of FIG. 3A will be described.

[0008] In the laminating component laminating step, the product portion 12a before pressing sandwiched by the release film 16 on the carrier plate 20 is laminated in a plurality of stages via the metal plate 17, and the outermost layer is formed by the dummy plate 18 One laminated component 11 is formed by being laminated so as to be sandwiched by the cushion material 19 through the intermediary. The product portion 12a before pressing is a so-called B-stage in a semi-cured state in which glass fiber or aramid fiber is processed into a woven or non-woven fabric and impregnated with a thermosetting resin on both sides of an inner layer material 15 having a circuit formed on both sides. The formed prepreg 13 and the copper foil 14 are placed and formed.

Next, a plurality of the laminated components 11 are formed.
Is transported to the hot press step of FIG.

In the hot pressing step shown in FIG. 3 (b), the transported plurality of laminated products 11
And is inserted between the upper hot platen 22a and the lower hot platen 22b. The upper hot platen 22a and the lower hot platen 22b are fixed to the upper fixed platen 24 and the lower movable platen 25 via the upper heat insulating plate 26a and the lower heat insulating plate 26b, respectively. Accordingly, the laminated component 11 inserted between the upper and lower hot plates 22a and 22b is driven upward by the hydraulic cylinder 23 so that the laminated component 11 is moved upward and downward.
a, 22b and heated and pressurized.

The heating and pressurizing process in the hot pressing device 21 is usually called a hot pressing process. In this process, the prepreg resin 13 in the B-stage state is bonded to the copper foil 14 and the inner layer material 15 by being melt-hardened. Molded as a multilayer circuit laminate.

The laminated component 11 which has completed the hot pressing process
Are transported to the laminated component disassembling step of FIG. 3C, and are specifically taken out for each carrier plate 20 (not shown), and the cushion material 19 and the dummy plate 1 are sequentially arranged from the top.
8. The metal plate 17 is removed, and the pressed product part 12
A plurality of pressed product parts 12b are taken out with the release film 16 adhered to both surfaces of b, and the release film 16 is peeled off from the product part 12b to obtain the product part 12b. The product part 12b after the hot pressing obtained through these steps is then subjected to a circuit forming step for forming a desired circuit on the outermost layer, a solder resist insulating layer forming step, and the like, to form a multilayer circuit board. Completed as

Here, the operation of a general hot press apparatus 21 used in the above-described hot press step will be described.

The heating conditions at the time of hot press molding are as follows: the temperature is raised to 180 to 230 degrees while pressurizing the upper and lower hot plates 22a and 22b, held for a certain period of time, and then lowered to room temperature. General.

Here, the upper and lower heat insulating plates 26a, 26
The role of b is that the upper and lower hot plates 2
When the laminated component 11 is sandwiched between 2a and 22b, the heat conduction between the upper and lower heating plates 22a and 22b and the upper fixed plate 24 and the lower movable plate 25 is cut off. The temperature control of the lower heating plates 22a and 22b can be performed accurately, and the heating control for the laminated component 11 can be performed efficiently, accurately, and easily. Further, the lower heat insulating plate 26b sandwiched between the lower movable platen 25 and the lower heating plate 22b also serves to insulate the hydraulic cylinder 23, so that the hydraulic cylinder 23 main body undergoes thermal expansion and the press pressure fluctuates. It is possible to prevent that.

[0016]

However, when the upper and lower hot plates 22a and 22b are heated to 180 to 230 degrees, the upper and lower heat insulating plates 26a and 26b become 6 inches.
The temperature is raised to 0 to 100 degrees, and the upper and lower
As the temperatures of a and 26b rise, the upper fixed platen 24, the lower movable platen 25, and the hydraulic cylinder 23 also rise in temperature to 30 to 50 degrees.
As a result, the upper and lower heat insulating plates 26a, 26a,
26b generates friction as a result of a dimensional change due to thermal expansion. When this is repeated, the upper and lower heat insulating plates 26a and 26b, which are necessarily made of resin, are deformed due to rubbing deterioration.
6a and 26b have variations in thickness, and the laminated structure 1
The pressure applied to 1 becomes non-uniform.

This problem is particularly remarkable when the laminated components 11 are stacked in multiple stages in a hot pressing step in order to improve productivity.

As a countermeasure against this, the pressure equalizing property of a hot press having a conventional structure is checked once every two to three months with a pressure-sensitive paper (prescale) or the like. It is necessary to replace the lower heat insulating plates 26a and 26b, and the maintenance is very complicated.

In particular, in recent circuit boards, it has been demanded to control the impedance of the circuit to a desired value or to reduce the tolerance of the board thickness for use in thin electronic equipment. Correspondingly, if the prescribed value of the pressure variation is strictly controlled, the upper and lower insulating plates 2 are frequently
The replacement of 6a and 26b was required, and the maintenance was very poor.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and more precisely and more easily maintains the pressure equalizing property during hot press molding, and can manufacture a high-quality circuit board. The purpose is to provide.

[0021]

In order to achieve this object, the present invention provides a heating plate which is provided in contact with an upper fixed plate or a movable plate via an insulating plate, and a lower fixed plate or a movable plate. A hot press device that includes a hot plate placed in contact with a movable plate via an insulating plate, and heats and presses a laminated structure placed on a lower hot plate with a hot plate positioned above and below,
A circuit board is laminated and manufactured by using a hot press device provided with a cushioning material between the hot plate and the heat insulating plate or between the fixed plate or the movable plate and the heat insulating plate.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that a cushioning material is provided at least between a hot plate and a heat insulating plate and / or at least between a fixed or movable plate and a heat insulating plate. By using a cushioning material in the hot press device, the friction of the heat insulating plate generated under high temperature and high pressure conditions during hot pressing,
The deformation can be alleviated, and the variation in the thickness of the heat insulating plate due to the deformation can be prevented. Thereby, uniform pressurization becomes possible, and a flat laminated structure having high thickness accuracy can be provided. Furthermore, there is also a secondary effect that periodic inspections are facilitated and the facility maintenance costs can be reduced.

According to a second aspect of the present invention, there is provided a hot press apparatus according to the first aspect, wherein the cushioning material is mainly made of a fluorine-based rubber. It has the function and effect of being able to withstand the shape change, preventing the heat insulating plate from deteriorating more than the invention of claim 1, and exerting an excellent effect of equalizing the pressure.

According to a third aspect of the present invention, there is provided the heat press apparatus according to the first aspect, wherein a reinforcing base material is provided inside the cushioning material. By adding a core material to the rubber sheet, there is an operation and effect that the tensile properties are improved with respect to more stable shrinkage and pressure than the rubber sheet alone.

According to a fourth aspect of the present invention, there is provided the hot press apparatus according to the first aspect, wherein a reinforcing base material is provided outside the cushioning material. Claim 3 by attaching a woven fabric to both outer surfaces.
There is an effect that the sheet strength can be further increased as compared with the invention of (1).

According to a fifth aspect of the present invention, there is provided a hot press apparatus according to the first aspect, wherein a reinforcing base material is provided inside and outside the cushioning material. By combining the contents of the invention of the fourth aspect, the inside and outside of the rubber sheet itself are reinforced, the characteristics having more excellent pressure equalizing properties can be maintained, and there is an effect that deterioration of the cushioning sheet is prevented.

According to a sixth aspect of the present invention, there is provided the hot press apparatus according to any one of the third to fifth aspects, wherein the reinforcing base material of the cushioning material is a heat-resistant woven fabric. Having such a property, excellent characteristics of heat resistance can be maintained, and there is an effect that deterioration of the reinforcing base material on the surface of the cushioning sheet by hot pressing is prevented.

According to a seventh aspect of the present invention, there is provided a heat press apparatus according to the sixth aspect, wherein a heat-resistant nylon woven fabric is used as the heat-resistant woven fabric. By laminating a certain flexibility to the rubber sheet, it is easy to handle and has an effect that the maintenance cost of the equipment can be reduced.

The invention according to claim 8 of the present invention is the heat press device according to claim 6, wherein an aramid woven fabric is used as the heat-resistant woven fabric. There is an operation and effect that higher heat resistance and higher pressure resistance can be realized as compared with the invention of Item 7.

According to a ninth aspect of the present invention, there is provided the heat press apparatus according to the first aspect, wherein the thermal expansion coefficient of the cushioning material is smaller than that of the heat insulating plate. Since the coefficient is smaller than the heat insulating plate, the cushioning material can maintain a stable shape during hot pressing,
It has the effect of exhibiting an excellent effect on pressure equalization.

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

FIG. 1 is a schematic diagram showing a schematic configuration of a hot press apparatus according to an embodiment of the present invention.

First, the configuration of the hot press apparatus shown in FIG. 1 will be described.

A plurality of laminated components 2 formed in the laminate forming step shown in FIG. 3A are stacked in a plurality of stages together with the carrier plate 9 in the same manner as in the conventional example, and an upper hot platen 3a and a lower hot platen are provided. 3b. Here, the upper heating plate 3a
Is connected to the upper fixed platen 5 via the upper cushioning material 8a and the upper heat insulating plate 7a, and the lower hot platen 3b is connected to the lower cushioning material 8b and the lower heat insulating plate 7b.
The upper cushioning material 8a and the lower cushioning material 8b are fixed between the upper heating platen 3a and the upper heat insulating plate 7a, and between the lower heating platen 3b and the lower heat insulating plate 7b, respectively. This configuration is a feature of the present embodiment.

Thus, the dimensional change due to thermal expansion of the upper and lower heat insulating plates 7a, 7b generated under high temperature and high pressure conditions is absorbed, and the upper and lower heat insulating plates 7a, 7a generated by dimensional change and friction are absorbed. 7b can be prevented from being deformed and the thickness from varying. That is, the upper and lower hot plates 3a and 3b are heated to 180 degrees to 23 degrees by heating and pressing.
When the temperature rises to 0 degrees, the heat is transferred to the upper and lower cushioning materials 8a,
The upper and lower heat insulating plates 7a and 7b are transmitted to the upper and lower heat insulating plates 7a and 7b via the base 8b.
The temperature is raised to 0 to 100 degrees, and a dimensional change occurs due to thermal expansion.

However, since the upper and lower cushioning members 8a and 8b are flexible, the upper and lower heat insulating plates 7a and 7b are provided.
The upper and lower heat insulating plates 7a, 7
b between the upper and lower cushioning materials 8a and 8b, the upper and lower hot plates 3a and 3b and the upper and lower cushioning materials 8a and 8b.
Between them, it is difficult to generate friction, and it is possible to prevent the conventional deformation due to rubbing deterioration. Thereby, uniform pressurization becomes possible, and a flat laminated structure having high thickness accuracy can be provided. Further, when the pressure equalization of the hot press molding is deteriorated, only the upper and lower cushioning materials 8a and 8b need to be replaced, so that the periodic inspection is further facilitated, and the secondary effect that the maintenance cost of the equipment can be reduced is also obtained. Have.

In this embodiment, the upper and lower cushioning members 8a and 8b are sandwiched between the upper and lower heating plates 3a and 3b and the upper and lower heat insulating plates 7a and 7b. A configuration in which upper and lower cushioning materials 8a and 8b are sandwiched between the panel 6 and the upper and lower heat insulating plates 7a and 7b, or between the upper and lower heat plates 3a and 3b and the upper and lower heat insulating plates 7a and 7b, and a fixed plate 5
Alternatively, the upper and lower cushioning members 8a and 8b may be sandwiched between the movable platen 6 and the upper and lower heat insulating plates 7a and 7b. Next, the operation and effect of these configurations will be described.

Generally, when friction occurs between the upper and lower heat insulating plates 7a and 7b during hot pressing, the fixed platen 5 and the movable platen 6 adjacent thereto vibrate due to the friction, and as a result, the hot press device 1 connected to them. Are also affected by vibration. When this is repeated, the accuracy of the main body of the hot press apparatus 1 may be affected. Further, the rubbing deterioration occurring between the fixed platen 5 or the movable platen 6 and the upper and lower heat insulating plates 7a, 7b is smaller than that between the upper and lower heating plates 3a, 3b and the upper and lower heat insulating plates 7a, 7b. Is caused by dimensional changes of the upper and lower heat insulating plates 7a and 7b.

As described above, the configuration in which the upper and lower cushioning members 8a and 8b are sandwiched between the fixed platen 5 or the movable platen 6 and the upper and lower heat insulating plates 7a and 7b is different from the above in that the upper and lower cushioning members 8a and 8b are formed by a hot press. 1 and upper and lower heat insulating plates 7a and 7b of the fixed platen 5 and the movable platen 6 directly installed on
Has the effect of reducing the effect on friction from This alleviates vibration of the fixed platen 5 and the movable platen 6 due to friction and the like, and also alleviates vibration of the main body of the heat press 1 directly linked to these. Also, the upper and lower cushioning materials 8a, 8
Since b has an effect of reducing the rubbing deterioration of the upper and lower heat insulating plates 7a and 7b, it has an effect of reducing the deformation and thickness variation of the upper and lower heat insulating plates 7a and 7b as compared with the configuration of the conventional apparatus. Specifically, the configuration of this device is a conventional IVH in which the conductive paste is not filled in the through holes.
This is effective for a circuit board having an (inner via hole) structure.

On the other hand, both the upper and lower heat plates 3a and 3b and the upper and lower heat insulating plates 7a and 7b and the fixed and movable plate 6 or the movable plate 6 and the upper and lower heat insulating plates 7a and 7b both have upper and lower shock absorbers. The configuration in which the members 8a and 8b are sandwiched is a configuration in which the upper and lower cushioning members 8a and 8b are sandwiched between the fixed board 5 or the movable board 6 and the upper and lower heat insulating plates 7a and 7b in addition to the configuration of the above-described embodiment. By sandwiching the upper and lower cushioning members 8a and 8b between the fixed platen 5 or the movable platen 6 and the upper and lower heat insulating plates 7a and 7b as described above, the upper and lower heat insulating plates 7a are different from those of the above embodiment. , 7b has an additional effect on preventing deformation and thickness variation due to rubbing deterioration, and has an effect on alleviating the vibration of the hot press apparatus 1. Further, the heat insulating effect on the fixed platen 5 or the movable platen 6 and the hydraulic cylinder 4 is further improved. The structure of this apparatus is particularly effective for forming a high-density and high-precision circuit board used for bare chip mounting, multi-pin semiconductor mounting, and the like.

Further, by sandwiching a fluorine-based rubber sheet between the upper and lower cushioning members 8a and 8b, the upper and lower heat insulating plates 7a and 7b exhibit a further effect in preventing a thickness variation due to deformation or deterioration due to friction with the upper and lower heat insulating plates 7a and 7b. In addition, the life of the lower heat insulating plates 7a and 7b can be extended.

The fluorine-based rubber sheet-like cushioning material (manufactured by Kaneyo Co., Ltd.) used in the present invention is commercially available, has no special use, and is easy to handle. In particular, regarding heat resistance, since it is a fluorine-based material, it can be used up to 280 degrees as a heating condition, and there is no problem in use in hot press molding.

Further, one layered reinforcing substrate 10 as shown in FIG. 2 (a) or a plurality of layers as shown in FIG. 2 (b) are provided inside the upper and lower cushioning members 8a and 8b in the form of a fluorine rubber sheet. Is provided on the entire surface of the cushioning material, thereby improving the tensile properties against shrinkage and pressure more stable than the fluorine-based rubber sheet alone. In addition, by attaching a reinforcing base material to both outer surfaces, it is possible to further increase the sheet strength, and furthermore, by providing a reinforcing base material to both the inside and the outside, the inside and outside of the rubber sheet are reinforced, and compared to the case of the inside or outside alone This has the effect of maintaining excellent pressure equalizing properties.

Further, by using a heat-resistant woven fabric as the reinforcing base material, it is possible to maintain the excellent heat resistance of the cushioning material, and to prevent deformation or deterioration of the reinforcing base material on the surface of the buffer material sheet by hot press molding. It has the effect of. By using a heat-resistant nylon woven fabric as the reinforcing base material, the flexibility, which is a characteristic of the heat-resistant nylon woven fabric, is attached to the fluorine-based rubber sheet, so that the handling is easy and the maintenance cost of the equipment can be reduced. Also, the use of aramid woven fabric has the effect that higher heat resistance and higher pressure resistance can be realized than with nylon woven fabric.

In addition to the above-mentioned improvement of the physical strength, the structure in which the reinforcing base material is provided inside the upper and lower cushioning members 8a and 8b in the form of a fluororubber sheet facilitates handling and is suitable for mass production. As a result, the production cost of the rubber sheet can be reduced.

Next, the operation of the hot press apparatus 1 of the present invention will be described.

A plurality of laminated components 2 formed in the laminate forming step shown in FIG. 3A are stacked in a plurality of stages together with the carrier plate 9 in the same manner as in the conventional example, and an upper hot platen 3a and a lower hot platen are formed. 3b.

The laminated component 2 placed on the lower hot platen 3b
Is driven upward by a hydraulic cylinder 4 and is heated and pressurized while being sandwiched between upper and lower hot plates 3a and 3b.

A pipe (not shown) for heating the inside of the upper and lower hot plates 3a, 3b and passing oil or steam there.
Is installed, and because it is densely piped inside the hot platen,
The laminated component 2 can be heated uniformly.

The hydraulic cylinder 4 is supplied with high-pressure hydraulic oil, and can pressurize the laminated component 2 at an arbitrary pressure.

The heating conditions at this time are as follows: the temperature is raised to 180 to 230 degrees while pressurizing the upper and lower hot plates 3a and 3b, held for a certain time, and then lowered to room temperature.

The laminated component 2 that has been heated and pressurized and has been subjected to the hot pressing step is conveyed to the laminated component disassembly step as in the related art, taken out for each carrier plate 9, and taken out of the cushion material, the dummy plate, and the like in order from the top. By removing the metal plate and peeling off the release film, the product part after pressing is taken out (not shown). Thereafter, the product portion is completed as a multilayer circuit board through a circuit forming process for forming a desired circuit on the outermost layer, a solder resist insulating layer forming process, and the like.

In the above-described hot pressing step, the hot press apparatus 1 can set heating and pressurizing conditions as conditions for performing resin molding of the prepreg in the B-stage state.

The importance of the pressing conditions is that the upper and lower hot plates 3a, 3a
b, equalizing properties of the upper and lower heat insulating plates 7a, 7b are required.

The pressure equalizing properties of the upper and lower hot plates 3a, 3b and the upper and lower heat insulating plates 7a, 7b greatly contribute to the moldability of a multilayer board such as a thin board or a fine pattern. The contents of the defect caused by the equalizing property include a difference in thickness due to the unevenness of the circuit of the inner layer material and the filling property of the prepreg resin.

In particular, in a high-density circuit board in which the pitch between lines / spaces is reduced by finer circuits, moldability has been demanded as an important condition.

In a multilayer board having an IVH (inner via hole) structure in which an inner layer and an outermost layer, or an inner layer material has a conductive hole, a technique of aligning circuits between layers or IVH and connecting layers at a fine connection pitch. Is required, and the pressure equalization of the hot platen and the heat insulating plate has an important influence on the alignment between layers and the connection between layers.

In particular, the conductive paste is filled in the through holes,
In a multilayer circuit board having an IVH structure for achieving interlayer connection, it is important in terms of stabilization of the conduction resistance value.

[0059]

As described above, the hot press apparatus of the present invention
The structure in which the cushioning material is sandwiched between the heat insulating plate and the hot plate prevents deformation and deterioration due to wear of the heat insulating plate, and can be used stably for a long period of time as a pressure equalizing guarantee of the hot press device. Further, when the pressure equalizing property of the hot press molding is deteriorated, it is only necessary to replace the cushioning material, so that the pressure equalizing adjustment and the periodic inspection can be easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a heat press device according to an embodiment of the present invention.

FIG. 2 is a schematic view of a reinforcing base material provided inside the cushioning material of the present invention.

FIG. 3 is a process diagram showing an outline of a multilayer circuit board manufacturing process using a conventional hot press machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat press apparatus 2 Laminated component 3a Upper heating plate 3b Lower heating plate 4 Hydraulic cylinder 5 Upper fixed plate 6 Lower movable plate 7a Upper heat insulating plate 7b Lower heat insulating plate 8a Upper buffer material 8b Lower buffer material 9 Carrier plate 10 Reinforcement base material

Claims (9)

[Claims] 1. An upper heating plate provided on an upper fixed plate or movable plate via an upper heat insulating plate, and a lower portion contacted and installed on a lower movable plate or fixed plate via a lower heat insulating plate. A hot press apparatus that includes a hot platen, and heats and presses the laminated structure mounted on the lower hot platen by moving the movable platen to the fixed platen side, wherein at least the upper hot platen or the lower hot platen and A heat press device comprising a buffer between heat insulating plates and / or at least between the fixed platen or movable platen and the heat insulating plate. 2. The hot press apparatus according to claim 1, wherein the cushioning material is mainly made of a fluorine-based rubber. 3. The hot press apparatus according to claim 1, wherein a reinforcing base material is provided inside the cushioning material. 4. The hot press apparatus according to claim 1, wherein a reinforcing base material is provided outside the cushioning material. 5. The hot press apparatus according to claim 1, wherein a reinforcing base material is provided inside and outside the cushioning material. 6. The hot press apparatus according to claim 3, wherein the reinforcing base material of the cushioning material is a heat-resistant woven fabric. 7. The heat press device according to claim 6, wherein a heat-resistant nylon woven fabric is used as the heat-resistant woven fabric. 8. The hot press apparatus according to claim 6, wherein an aramid woven fabric is used as the heat-resistant woven fabric. 9. The hot press apparatus according to claim 1, wherein the thermal expansion coefficient of the cushioning material is smaller than that of the heat insulating plate.