JPS6233580A - Method and apparatus for heat treatment of high-polymer resin layer - Google Patents

Abstract

PURPOSE:To obtain high-polymer insulating films having uniform quality within substrates and between substrates by placing the substrates on which the high- polymer resin layers are formed, by each sheet, on a conveying belt at every formation of the substrates and successively carrying the same into a heating furnace by the movement of the conveying belt and subjecting the substrates to a heat treatment. CONSTITUTION:The substrate (sample) 2 is placed on the conveying belt 1 at every formation of the high-polymer resin layer (e.g., polyimide resin layer) on a sheet of the substrate 2, then the substrates 2 are automatically arrayed in one row on the belt 1 and are successively carried into the heating furnace 3. The substrates are subjected to the heat treatment in the preset required atmosphere. Since the moving speed of the belt 1 is constant, all the substrates are subjected to the uniform heat treatment and the temp. distribution on a sheet of the substrate in the furnace is maintained uniform. The heat treatment conditions within and between the substrates are made uniform and the high- polymer insulating films having the uniform quality are obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a heat treatment method and a heat treatment apparatus for a polymer resin layer of a circuit board, and in particular, in a hybrid integrated circuit 2 and a printed wiring board, The present invention relates to a heat treatment apparatus and a heat treatment method for forming an insulating layer of a multilayer structure wiring body having a polymer insulating coating.

[Conventional technology]

Conventionally, a hot air circulating type opening is used to heat and cure a polymer resin layer formed on a predetermined substrate, thereby forming a polymer insulating film. According to this method, a heat-cured polymer insulating film can be obtained by leaving the substrate on which the polymer 1 resin layer has been formed in an open chamber preset at a predetermined temperature for a predetermined time. The method of heat-treating a polymer resin layer using an open method has the advantage of being relatively simple because the treatment temperature and time can be easily controlled.

[Problem that the invention seeks to solve]

By the way, the polymer resin layer at the stage where it is formed on the substrate is unstable because it contains four agents and the like.

Therefore, it is necessary to perform heat treatment immediately after forming the resin layer to scatter volatile components and stabilize the resin layer.

The above processing is possible when there is only one substrate to be processed, but when processing a large number of substrates, the resin layer is formed one by one and then heat treated, so opening and closing the door is not necessary. becomes frequent. This brings about a phenomenon in which the atmosphere J and temperature within the oven become non-uniform. As a result, the quality of the polymer insulating film obtained by the heat treatment, for example, the dielectric strength voltage of the film, becomes non-uniform.

Furthermore, when using a heat-resistant polymer resin (for example, polyimide resin) as the polymer resin, in order to obtain a film with excellent electrical insulation, the processing temperature may be lowered (for example, 150°C).
It is necessary to change the temperature to the next higher temperature (for example, 300° C.) and perform the heat treatment multiple times.

That is, strict control of the heat treatment process is required.

In addition, when using a photosensitive heat-resistant polymer resin (for example, Photoneeds, manufactured by Toshisha Co., Ltd., trade name) as the polymer resin, heat curing treatment is applied to the resin layer on which a pattern has been formed in advance, so the heat treatment process This affects not only the dielectric strength but also the cross-sectional shape of the pattern.

For example, if a patterned polymer resin layer is heat-cured using an open pattern, the pattern cross-sectional angle (
This causes deterioration of the pattern shape, such as variations in the angle between the cross section of the pattern and the substrate, and the formation of bulges around the pattern.As a result, the conductor layer on the polymer insulation coating becomes easily disconnected. .

In other words, in the conventional open heat treatment method for a polymer resin layer, in addition to the 4C problems of non-uniformity, variation, and lack of reproducibility within and between substrates, it is also possible to form a polymer insulating film with a controlled cross-sectional pattern shape. This invention has been made to solve the above-mentioned problems, and is aimed at improving the uniformity within and between substrates in the heat treatment of the coating on a substrate having a polymer resin coating. It is an object of the present invention to provide a heat treatment method and apparatus thereof that have good reproducibility and that can also maintain the cross-sectional shape of a pattern.

[Means for solving problems]

In the method for heat treatment of four layers of polymeric tree according to the first invention.

Polymer 4tI! The substrates on which the fat layer force has been formed are placed one by one on a conveyor belt each time a substrate is formed, and as the conveyor belt moves, they are sequentially carried into a heating furnace, and the substrates are heated as they are moved through the furnace. The heat treatment apparatus for a polymer resin layer according to the second invention is an apparatus for implementing the method according to the first invention, in which the substrate sample is further transferred from outside the furnace to inside the furnace at a bt constant speed. It is equipped with a sample transport belt for transporting the sample to the outside of the furnace, a plurality of heating element units for heating the substrate on the heald inside the furnace, and a gas inlet and a gas exhaust port for maintaining the required atmosphere inside the furnace. .

[For production]

In this invention, a polymer resin layer is formed on a single substrate.
When the substrates are placed on the sample transport belt, they are automatically placed on the belt in seven rows and are sequentially carried into the heating furnace where they are placed in a preset required atmosphere. However, since the conveyance speed of the belt is constant, each substrate undergoes uniform heat treatment, and of course the temperature distribution on one substrate in the furnace is kept uniform, and the temperature distribution within the substrate and The heat treatment conditions between the substrates become uniform.

〔Example〕

Figure 1 is a cross-sectional view showing the heat treatment apparatus for a single polymer sealing layer according to the present invention and the heat treatment situation using the same. (1) is a sample transport bell, +21 is the bell) f:
(3) is the heating furnace, (4) is the substrate (sample') placed in
is the inlet of the heating furnace (3), (5) is the outlet of the heating furnace (3),
(6) is a heating element unit disposed inside the heating furnace 13), (7) is a gas inlet into the inside of the heating furnace (3), (
8) is a gas exhaust port from inside the heating furnace 13).

The sample transport belt (1) has an annular shape and has an entrance (
4) into the heating furnace (3) and the heating element unit (6).
), go out from exit (5) and go back to the entrance (
It is back to 4). In this example, the belt (1) is 1
The case is shown in which four heating element units (6) are provided on each of the upper and lower surfaces.

The temperature profile that the sample (2) undergoes is the set temperature of the heating element unit (6), its total cast length, the conveyance of the bell) fl) at 4 degrees, and the gas introduction from the gas inlet (7) and outlet (8). It is determined by the discharge method and discharge method, so it is necessary to set each condition accurately.

The specific temperature setting depends on the characteristics of the polymer resin layer (especially heat resistance)
However, in the case of polyimide resin, the maximum heat treatment temperature is generally about 400°C. The heat treatment time at the maximum temperature is determined by the time needed to stabilize the polymer resin layer. When the pot molecular resin layer is heat treated with polyimide under the conditions shown in A in the same figure, the belt against the heating element (6) (
Since the transport speed of 1) can be increased, there is an advantage that the number of samples (2) to be processed can be increased. On the other hand, Fig. 2B
When the polymer resin layer is heat-treated under the conditions shown in , sample (2)
Since the film is subjected to heat treatment in stages, it has the advantage that the film quality and stability of the film are further improved.

FIG. 3 is a sectional view of a hybrid integrated circuit board on which a multilayer structure wiring body is formed on the surface of the board. In the figure, (6) is an alumina substrate, a is a resistor made of ruthenium oxide (Rust), and (to) is a resistor made of ruthenium oxide (Rust).
α4J and αQ are photosensitive heat-resistant polymer resin layers made of photosensitive polyimide resin, d) is a second conductive layer made of Cu, and (b) is solder.

(G) is a chip product, α9. [ is a through hole.

First, a resistor U is formed on an alumina substrate (11).

Next, a first conductor layer (2) having a predetermined pattern is formed.

On top of that, a photosensitive heat-resistant polymer resin layer α blue is formed. This resin layer α is exposed to light in a predetermined pattern, and then developed and unnecessary parts are dissolved and removed to form one through hole A9. It hardens to complete the insulating layer α. Next, a second conductor layer (G) is formed through the through hole 4, and an insulating layer σ and a through hole ω are provided thereon in the same manner as described above. Then, the wiring conductor of the alumina circuit board is electrically connected to the chip component by solder (X7) through the through hole.

In Example IC of this heat treatment method, polyimide resin layer α4. The heat curing treatment of α-moon was carried out as follows. That is, the polyimide resin layer on which a predetermined pattern was formed was heat-treated using the apparatus shown in FIG. Then, the heat treatment temperature profile is as shown in Figure 2B.
The temperature of each heating element unit (6) and the speed of the conveyor belt (1) were set. 1st° 2nd and 30th heat treatment temperatures were 160'C, 1200°C and 350°C, respectively, and the treatment time was 30 minutes, respectively.

The heating time was 30 minutes and 1 hour, and the heating rate was 10°C/min.

The atmosphere in the furnace was nitrogen (N) in order to maintain the film quality of the film. Furthermore, since the conductor layers (2) and (g) are made of Cu, which is easily oxidized, the amount of nitrogen and gas introduced is controlled so that the amount of residual oxygen (0) is 20 ppm or less. ).Furthermore, in order to ensure that the sample is cooled at the outlet (5) of the heating furnace (3), the final end of the heating element unit (6) and the heating furnace (3)
(1m in this example)
) + Kotatta. Of course, since the sample is continuously heat-treated,
The conveyance speed of the belt C1) is constant (20ras in this example).
/min).

This results in a polyimide insulation coating on the circuit board.

A hybrid integrated circuit board with excellent electrical insulation and a normal cross-sectional pattern shape can be obtained, resulting in a hybrid integrated circuit board with the desired characteristics! production is possible.

In the apparatus of the above embodiment, the number of heating element units was set to 4 units/unit, but it is not necessary to stick to the above embodiment as long as the quality of the coating and the number of samples to be processed are ensured. For the same reason, it is not necessary to use only one sample conveying belt, and there is no problem even if two or more belts are provided in parallel. In addition, in order to cool the sample to near room temperature, a sufficient distance was provided from the final heating element unit to the heating furnace outlet, but for example, the cooling zone was installed immediately after the heating zone where the heating element unit was located. The distance may be shortened by this. As a result, if the sample is cooled to about room temperature near the heating furnace outlet, it is sufficient to achieve the purpose of the present invention. The main idea is to maintain the atmosphere inside the furnace at a certain level,
1) Since the temperature distribution must be strictly controlled, the method can be determined as appropriate when designing the heat treatment equipment. The amount of remaining 02 in the furnace is controlled by
For example, it is extremely effective when processing a substrate with a wiring layer, such as copper, which is extremely susceptible to heat distribution.

For the same reason, the material and structure of the heating element unit, belt, furnace, etc. may be arbitrary.In order to form an insulating coating with a polymer resin layer, materials with thermal stability of 500 to 600°C,
[Effects of the Invention] As detailed above, in the present invention, a polymer resin layer is formed and the F-substrates are sequentially placed on the conveyor belt.

One movement of this conveyor belt transports it into the heating furnace, and heat treatment is applied to the coating while moving inside the furnace.
The heat treatment conditions are kept uniform not only within one six-board board, but also between each board, and a homogeneous polymer insulating film can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a schematic configuration of an embodiment of a heat treatment apparatus for a polymer resin layer according to the present invention, Fig. 2 is a view showing a heat treatment temperature profile thereof, and Fig. 3 is a diagram showing the heat treatment temperature profile of the polymer resin layer heat treatment apparatus according to the present invention. 1 is a cross-sectional view showing an example of a hybrid integrated circuit board. In Figure 2, (1) is the sample transport belt, and (2) is the sample. Is (3) heating? , (6) is a heating element unit, (7) is a gas introduction system, and (8) is a gas exhaust system. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (6)

[Claims] (1) Place the substrate on which the polymer resin layer is formed on a conveyor belt, and heat-treat the polymer resin layer while moving the substrate in the heating furnace together with the conveyor belt passing through the heating furnace. 1. A method for heat treating a polymer resin layer, the method comprising: obtaining a polymer insulation coating. (2) The method for heat treatment of a polymer resin layer according to claim 1, wherein the polymer resin layer is formed on a substrate having a conductor layer made of copper. (3) The method for heat treatment of a polymer resin layer according to claim 1 or 2, wherein the polymer resin layer is a polyimide resin layer. (4) Claims 1 to 3, characterized in that the heat treatment is performed in a heating furnace at a temperature above room temperature and below 500°C.
A method for heat treatment of a polymer resin layer according to any one of the above. (5) Claims 1 to 4 characterized in that the atmosphere in the heating furnace has an oxygen concentration of 100 ppm or less.
A method for heat treatment of a polymer resin layer according to any one of the above. (6) A sample conveying belt that runs longitudinally through the heating furnace, is driven at a constant speed, is placed on top of the heating furnace, and conveys the sample having a polymer resin layer on its surface; A heat treatment apparatus for a polymer resin layer, comprising a plurality of heating element units arranged along the line and each having a temperature settable, and a gas introduction system and a gas exhaust system for maintaining the inside of the heating furnace in a desired atmosphere.