JP2011224795A - Method for producing multilayer copper-clad laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a multilayer copper-clad laminated sheet that prevents warpage, variation of its dimensional accuracy by uniform dimensional shrinkage, and deformation (distortion) of the multilayer copper-clad laminated sheet.SOLUTION: The multilayer copper-clad laminated sheet includes an inner layer circuit board in which a circuit has been formed in advance, an outer layer plate or copper foil, and a prepreg. The method of producing the multilayer copper-clad laminated sheet includes the steps of: superposing the inner layer circuit board with the circuit formed thereon on the outer layer plate or the copper foil through the prepreg to form a laminate; alternately laminating the laminates and metal plates to an allowable height in a press stage; heat-pressing the laminates by a press and bonding them to form a multilayer copper-clad laminated sheet; and immediately after the heat-pressing, extracting the multilayer copper-clad laminated sheet and the metal plates from the inside of the press stage while being alternately laminated, and leaving them to cool down.

Description

  The present invention relates to a method for producing a multilayer copper clad laminate.

In recent years, with the increase in performance and functionality of electronics, the density of printed wiring boards has increased and the number of layers has increased. In the production of multilayer printed wiring boards, it is known to perform multilayer lamination molding at low pressure in order to reduce the dimensional change. However, there is a problem of generating voids and blurring in low pressure molding, and in order to prevent this, lamination molding is also performed at a reduced pressure using a vacuum enclosure press. Further, the size has been controlled by correcting the size at the time of design.
In addition, in a method for producing a multilayer copper-clad laminate, in which a dimensional change when processing a multilayer printed wiring board is small, a method is disclosed in which heat treatment is further performed in a temperature range of a lamination molding temperature ± 20 ° C. after heating and pressing. (See Patent Document 1).

Japanese Patent Laid-Open No. 5-147058

A conventional method for manufacturing a multilayer copper clad laminate is a state in which a pre-circuited inner layer circuit board is combined with a prepreg, and a copper foil is combined with an outermost layer. After stacking, combining and inserting into the press machine, the multilayer copper clad laminate was manufactured through the process of heating and pressurization and further cooling by automatic control by the press machine, but due to the rapid cooling in the cooling process The warp of the multilayer copper clad laminate, and further deformation (distortion) occurs, and the cooling of the multilayer copper clad laminate is from the bottom of the multilayer copper clad laminate combined in the press stage to the center side in the press stage. Therefore, a difference in dimensional shrinkage between the multilayer copper clad laminate at the lowermost position in the press stage and the multilayer copper clad laminate on the center side, that is, variation in dimensional accuracy within the press stage occurred.
The present invention can suppress warping of a multilayer copper-clad laminate, uniformly reduce dimensional shrinkage, suppress variation in dimensional accuracy, and further suppress deformation (distortion) of the multilayer copper-clad laminate. The present invention provides a method for producing a multilayer copper-clad laminate that can be used.

The present invention is as follows.
(1) In the manufacturing method of the multilayer copper clad laminated board which consists of the inner-layer circuit board by which the circuit was formed beforehand, the outer-layer board or copper foil, and the prepreg, the inner-layer circuit board by which the circuit was previously formed, the outer-layer board or copper foil, Are stacked through a prepreg to form a laminated body, the laminated body and the metal plate are alternately stacked up to an allowable height in a press stage, and the laminated body is heated and pressed by a press to form a multilayer. Multi-layer copper-clad laminate having a step of forming a multilayer copper-clad laminate by heating and pressurizing, and a step in which the multilayer copper-clad laminate and the metal plate are alternately stacked from the press stage immediately after heating and pressurizing and left to cool A manufacturing method of a board.
(2) The method for producing a multilayer copper-clad laminate according to (1), wherein the cooling rate of the multilayer copper-clad laminate is 3 ° C./min or less in the step of cooling by standing.

  According to the present invention, it is possible to suppress warping of a multilayer copper-clad laminate, uniformly reduce dimensional shrinkage, suppress variation in dimensional accuracy, and further suppress deformation (distortion) of the multilayer copper-clad laminate. It is possible to provide a method for producing a multilayer copper-clad laminate that is possible.

It is the schematic diagram which showed the leaving form and state of the multilayer copper clad laminated board when extracting from the press stage (inside the machine) in the high temperature state after heating and pressurization, ie, before cooling, and leaving it to cool. In the temperature chart of the multilayer copper clad laminate when the multilayer copper clad laminate is left as it is heated and pressurized in the press stage (in-machine) and allowed to cool at a cooling rate of 3 ° C / min or less. is there.

  The method for producing a multilayer copper-clad laminate of the present invention is a method for producing a multilayer copper-clad laminate comprising an inner-layer circuit board formed in advance with a circuit, an outer layer board or copper foil, and a prepreg. A step of laminating a circuit board and an outer layer plate or copper foil through a prepreg to form a laminated body, a step of alternately laminating the laminated body and a metal plate to an allowable height in a press stage, and the laminating The process of heating and pressing the body to form a multilayer copper-clad laminate, and immediately after the heating and pressing, the multilayer copper-clad laminate and the metal plate are taken out from the press stage in a stacked form and allowed to cool. It has the process.

  In the method for producing a multilayer copper-clad laminate of the present invention, the multilayer copper-clad laminate that is alternately stacked with metal plates from the press machine in a high-temperature state after heating and pressing, that is, before cooling, is heated and pressurized in the press machine. It is extracted as it is and allowed to cool. Alternatively, the stacked form may be extracted and left to cool. Therefore, the process of cooling is not performed in the press stage (inside the machine) after heating and pressurization.

In addition, the present invention is a method in which a multilayer copper clad laminate is alternately stacked with metal plates from the press machine in a high temperature state after heating and pressing, that is, before cooling, and the combined multilayer copper clad laminates are extracted in the form of being heated and pressed in the press machine. It is preferable to stand and cool at a cooling rate of 3 ° C./min or less. The cooling rate of the multilayer copper clad laminate is more preferably 2 ° C./min or less, and particularly preferably 1 ° C./min or less.
The cooling rate is the cooling rate of the multilayer copper-clad laminate and can be measured with a thermocouple or the like. When the cooling rate exceeds 3 ° C./min, the cooling is rapid and the warp of the multilayer copper-clad laminate tends to occur.

In addition, the present invention is a method in which a multilayer copper clad laminate is alternately stacked with metal plates from the press machine in a high temperature state after heating and pressing, that is, before cooling, and the combined multilayer copper clad laminates are extracted in the form of being heated and pressed in the press machine. It is possible to suppress warping of the multilayer copper-clad laminate by leaving it to stand and cooling it at a cooling rate of 3 ° C./min or less.
In addition, the present invention is a method in which a multilayer copper clad laminate is alternately stacked with metal plates from the press machine in a high temperature state after heating and pressing, that is, before cooling, and the combined multilayer copper clad laminates are extracted in the form of being heated and pressed in the press machine. By allowing to stand and cooling at a cooling rate of 3 ° C / min or less, the dimensional shrinkage of multilayer copper clad laminates combined with metal plates in the press stage can be uniformly shrunk, and variation in dimensional accuracy can be suppressed. It is possible to suppress deformation (distortion) of the copper-clad laminate.

The manufacturing method of the multilayer copper clad laminate of the present invention will be described in detail. After heating and pressurizing in the press machine, that is, in a high temperature state before cooling, it is extracted from the press machine in the form of being heated and pressurized and allowed to cool, but the cooling at this time can be cooled at 3 ° C./min or less, Usually, the outside temperature of the environment in which the multilayer copper-clad laminate is left is adjusted. Therefore, 10-40 degreeC is preferable and, as for outside temperature, 20-35 degreeC is more preferable. Also, multilayer copper-clad laminates removed at high temperatures are easily affected by neglected form / state and may be caused by warping, etc., so the neglected place is flat, that is, the multilayer copper-clad laminate is flat. It is preferable to be a place where a state is reached.
In addition, although the heating-pressing conditions in a press are not specifically limited, Usually, it is about 1-10 MPa, 80-250 degreeC, 20 minutes-about 10 hours. In the present invention, the inner layer circuit board, the outer layer board, the prepreg and the like used in the resin are generally used for multilayer boards such as polyimide resin, epoxy resin and polyester resin, and the prepreg base material used is , Glass cloth, polyester cloth, glass paper, etc.

EXAMPLES Hereinafter, although the suitable Example of this invention is described, this invention is not limited to these Examples.
Example 1
A glass substrate epoxy resin double-sided copper-clad laminate having a copper foil thickness of 35 μm and a total thickness of 0.28 mm was used as a sample, and the circuit was processed by an etching method, and the copper foil surface of the circuit was further oxidized. A prepreg having a resin content of 52% by impregnating and drying a varnish mainly composed of the same epoxy resin as that used for the inner layer circuit board on a glass cloth having a thickness of 0.1 mm above and below the inner layer circuit board obtained by the above method. A copper foil having a thickness of 18 μm was disposed on each of the sheets and further on the upper and lower sides thereof to form a laminate. As shown in FIG. 1, this laminate (multilayer copper clad laminate) and a metal plate are alternately stacked on a carrier plate up to an allowable height in the press stage, and an upper lid and cushion paper are further mounted. Overlap and insert into the press stage in this form. Furthermore, it was heat-press molded for 90 minutes at 2.94 MPa and 170 ° C. under reduced pressure to obtain a four-layer board (multilayer copper-clad laminate).
Further, without performing a cooling press, after heating and pressurizing, in the state of the above-described form, it was extracted from the press stage and left in an atmosphere of 25 ° C. As shown in the temperature chart of the multilayer copper clad laminate (see FIG. 2, the temperature inside the multilayer copper clad laminate is measured with a thermocouple), the cooling rate of the multilayer copper clad laminate was 3 ° C./min. It was.

(Comparative Example 1)
A glass substrate epoxy resin double-sided copper-clad laminate having a copper foil thickness of 35 μm and a total thickness of 0.28 mm was used as a sample, and the circuit was processed by an etching method, and the copper foil surface of the circuit was further oxidized. A prepreg having a resin content of 52% by impregnating and drying a varnish mainly composed of the same epoxy resin as that used for the inner layer circuit board on a glass cloth having a thickness of 0.1 mm above and below the inner layer circuit board obtained by the above method. A copper foil having a thickness of 18 μm was disposed on each of the sheets and further on the upper and lower sides thereof to form a laminate. As shown in FIG. 1, this laminate (multilayer copper clad laminate) and a metal plate are alternately stacked on a carrier plate up to an allowable height in the press stage, and an upper lid and cushion paper are further mounted. Overlap and insert into the press stage in this form. Furthermore, it heat-press-molded for 90 minutes at 2.94 MPa and 170 degreeC under pressure reduction, and it cooled for 30 minutes with the pressure, and obtained the 4 layer board (multilayer copper clad laminated board).

The amount of warpage and the dimensional change rate of the test piece of 500 × 500 mm taken from the four-layer board (multilayer copper-clad laminate) obtained in Example 1 and Comparative Example 1 were determined.
About the dimensional change rate, the change rate after the solder leveler in multilayer printed wiring board processing was calculated | required on the basis of the dimension of the multilayer board after multilayer lamination molding. The change rate of the multilayer board of Example 1 was 1%, and the change rate of the multilayer board of Comparative Example 1 was 2%.
The warpage amount of the test piece of Example 1 was 0.15 mm, and the warpage amount of the multilayer board of Comparative Example 1 was 0.5 mm.

  Pre-circuited inner layer circuit board is combined with prepreg, and copper foil is combined with outermost layer, and these are stacked alternately with metal plate up to the allowable range in the press stage, combined, heated and pressed to make multilayer In the manufacturing method of multilayer copper clad laminates to be adhesively bonded, the multilayer copper clad laminates that are alternately stacked with metal plates from the press machine in a high temperature state after heating and pressing, that is, before cooling, are heated and pressurized in the press machine. As it is, it is left as it is and allowed to cool at 3 ° C / min or less, so that the amount of warpage of the multilayer copper clad laminate is reduced by about 70% compared to the conventional method. The variation and deformation (distortion) of the dimensional accuracy of the multilayer copper-clad laminate made can be reduced by about 50% compared to the conventional case.

1. Upper lid, 2. Cushion paper, 3. Metal plate, 4. 4. Multi-layer copper clad laminate, Carrier board

Claims (2)

  In a method for producing a multilayer copper clad laminate comprising a pre-circuited inner layer circuit board, an outer layer board or copper foil, and a prepreg, the prepreg of the inner layer circuit board and the outer layer board or copper foil pre-formed with a circuit is prepared. A step of laminating and stacking the laminate and the metal plate alternately up to the allowable height in the press stage, and heating and pressurizing the laminate with a press for multilayer adhesion Production of a multilayer copper clad laminate, comprising a step of forming a multilayer copper clad laminate, a step of extracting the multilayer copper clad laminate and the metal plate from the press stage immediately after heating and pressing in a form in which they are alternately stacked, and allowing to cool. Method.   2. The method for producing a multilayer copper-clad laminate according to claim 1, wherein the cooling rate of the multilayer copper-clad laminate is 3 [deg.] C./min or less in the step of standing cooling.

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