JPH11112141A - Manufacture of multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the dimensional change in processing stage after multilayering by heat-treating a multilayer wiring board where an inner-layer circuit board and a prepreg are stacked into a multilayer, within the specified temperature range for stacking before circuit processing. SOLUTION: A laminate where both sides of glass base material epoxy resin are covered with copper is processed to make a circuit by etched foil method, and further oxidation treatment is applied to the surface of the copper foil 3 of the circuit. Copper foils are arranged through one sheet each of glass cloth base material epoxy resin prepreg 2 above and below this manufactured inner-layer circuit board 1. This combination constituent material is heated and pressurized at 2.94 MPa and 170 deg.C for 90 minutes in decompressed atmosphere, and then it is cooled for 30 minutes, with this pressure on, so as to make a four-layer board. Heat treatment at 160-180 deg.C for 60 minutes is applied to this four-layer board with a hot blast circulation system of drier. In the range of ±10 deg.C of this laminate formation temperature, the dimensional property can be improved most within the treatment temperature range fit for resin. Accordingly, dimensional change and dispersion are small, and further there is no discoloration of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a multilayer wiring board.

[0002]

2. Description of the Related Art In recent years, printed wiring boards have been increased in density and multilayered in accordance with higher performance and higher functionality of electronics, and multilayer printed wiring boards with less dimensional change have been desired. When manufacturing multilayer printed wiring boards, especially in the multilayer lamination molding process, molding is performed at low pressure in order to reduce the influence of pressure, and voids and fading, which are disadvantages that are likely to occur in low pressure molding because low pressure molding is performed. As a countermeasure, manufacturing is performed by reducing the pressure using a vacuum-enclosed press.

[0003] As a measure against dimensional change of the inner circuit board, heat treatment in the range from the glass transition temperature of the resin layer to the lamination molding temperature has conventionally been performed to remove the strain remaining in the board and reduce the variation in the coefficient of thermal expansion. It is known from Japanese Patent Application Laid-Open Nos. 1-215514 and 63-69625 that the dimensions during processing can be reduced by performing appropriate cooling methods after heat treatment. It has also been adopted and has gained its effect.

[0004]

However, these countermeasures were effective in reducing the dimensional change of the inner layer circuit board up to the multi-layer lamination, but were effective in the dimensional change in the processing step after the multi-layer lamination. Did not. Furthermore, with the recent progress of high-density wiring technology, higher dimensional characteristics have been required in the processing of a multilayer board, and a new technology capable of coping with this is required. The conventional method of heat-treating an inner-layer circuit board has a problem in that the required dimensional characteristics in a processing step after the multi-layer lamination cannot be satisfied.

According to the present invention, in a processing step after multilayering,
It is an object of the present invention to provide a method for manufacturing a multilayer wiring board having a small dimensional change.

[0006]

According to the present invention, there is provided a method for manufacturing a multilayer wiring board, comprising: forming a multilayer wiring board formed by laminating and laminating an inner layer circuit board and a prepreg;
It is characterized in that heat treatment is performed in a range of 0 ° C.

[0007] The dimensional change of the multi-layer board is the same as the dimensional change of the inner circuit board, and the amount of thermal expansion and the respective elastic modulus when the inner circuit board, the adhesive prepreg and the copper foil are integrated during the multilayer lamination molding. And appears as dimensional shrinkage after subsequent circuit processing. Therefore, in order to obtain a multilayer board having a good dimensional change in a processing step after multilayering, it is necessary to remove distortion remaining in the board after multilayering. The present invention provides a method of processing a circuit after heat-treating a multilayer board after multi-layer lamination molding at an optimal temperature range in which the discoloration of the substrate is small near the lamination molding temperature to achieve the above object. Further, in order to ensure the effect, the temperature of the heat treatment of the multilayer board needs to be within a range of the lamination molding temperature ± 10 ° C.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The resins used for the base material and prepreg of the present invention are all resins generally used for multilayer boards such as polyimide resin, epoxy resin and unsaturated polyester resin. It is a general base material used for multilayer boards such as paper and polyester cloth. The heat treatment temperature varies depending on the type of the resin and the base material used for the product, but in the case of a glass cloth base material and a general epoxy resin, the processing conditions of the multilayer board are a temperature of 160 to 180 ° C. and a time of 3 hours.
0 to 120 minutes is desirable. For conditions outside this range,
The effect on dimensional change is small, and if the temperature is too high, the resin undergoes thermal deterioration, causing discoloration of the substrate and other troubles.

[0009]

【Example】

Example Glass-based epoxy resin double-sided copper-clad laminate (FR-4,
A 0.28 mm, 35 μm copper foil) was used as a sample, which was processed by an etched foil method, and the surface of the copper foil of the circuit was oxidized. The inner-layer circuit board thus manufactured was configured as shown in FIG. 2 to obtain a four-layer board. Glass cloth base epoxy resin prepreg 2 above and below inner circuit board
A copper foil 3 (thickness: 18 μm) was arranged via one sheet (base material thickness: 0.1 mm, resin content: 51.5%). This combined constituent material was heated at 2.94 MPa, 170 ° C. 90
After heating and pressurizing for 30 minutes, cooling
For 4 minutes to obtain a four-layer plate. The four-layer plate was subjected to a heat treatment at 160 to 180 ° C. for 60 minutes by a hot air circulation type dryer.

Comparative Example 1 A four-layer plate was prepared under the same conditions as in the example, using the same glass-base epoxy resin double-sided copper-clad laminate as the sample as a sample.
A four-layer plate was obtained without heat treatment.

Comparative Example 2 Using the same glass-base epoxy resin double-sided copper-clad laminate as a sample as a sample, and forming a four-layer plate under the same conditions as in the example,
In the range of 120 to 150 ° C, 6
Heat treatment was performed for 0 minutes.

Comparative Example 3 The same glass-base epoxy resin double-sided copper-clad laminate as in the example was used as a sample, and a four-layer plate was produced under the same conditions as in the example.
In the range of 190-210 ° C, 6
Heat treatment was performed for 0 minutes.

[0013]

[Table 1]

Table 1 shows a comparison of the characteristics of each of the four-layer plates obtained in the examples and comparative examples 1, 2, and 3. Test piece size is 500 ×
The test method was as follows. Substrate discoloration: After heat treatment of the multilayer board, the copper foil was removed by etching, and the discolored state of the substrate was visually evaluated. ○ is good,
は: little discoloration, ×: multicolor change Dimensional change: The rate of change after solder leveler processing in the multilayer printed wiring board processing step was determined based on the dimensions of the multilayer board after multilayer lamination molding.

When the dimensional change of the embodiment of the present invention is shown in Table 1, the effect of the present invention is clearly remarkable as compared with the numerical value of the comparative example. The discoloration of the substrate is accompanied by the thermal deterioration of the resin. Under the conditions of Comparative Example 3, since the curing proceeds too much, the multilayer board inherently has a strain in the shrinkage direction, so that the variation in dimensional change is small, but the average is large and the resin is thermally degraded frequently. Therefore, the conditions of the embodiment are the best. Further, the results in Table 1 are shown in FIG. The method of the present invention takes into account the characteristics of the resin used for the inner layer circuit board and the prepreg, and newly finds a heat treatment temperature at which the dimensional characteristics can be improved most within a processing temperature range suitable for the resin. It is a thing. As is clear from Table 1 and FIG. 1, the dimensional change rate of the example is small, and there is no problem in discoloration of the substrate.

[0016]

As described above, according to the present invention, there is provided a method of manufacturing a multi-layer printed wiring board which has a small dimensional change and variation even in a multi-layer printed wiring board processing step after the multi-layering and which has no discoloration of the substrate. Can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram of a dimensional change rate for explaining an effect of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of one embodiment of the present invention.

[Explanation of symbols]

 1. 1. inner layer circuit board Prepreg 3. Copper foil

Claims (2)

[Claims] 1. A multi-layer wiring board in which an inner-layer circuit board and a prepreg are formed by multi-layer lamination and molding, before laminating, a lamination molding temperature ±
A method for producing a multilayer wiring board, comprising performing heat treatment at a temperature of 10 ° C. 2. An epoxy resin impregnated glass cloth base material is used for the inner circuit board and the prepreg, and the heat treatment temperature of the multilayer wiring board is 16
The method for producing a multilayer wiring board according to claim 1, wherein the temperature is in a range of 0 to 180 ° C.