JPH0595186A - Vapor-phase cracking reducing equipment for inner board - Google Patents

Abstract

PURPOSE:To automatize feeding/taking an internal layer board to/out of a reduction chamber by equipping a loader provided with the transfer function, middle platform provided with a feeding/taking out apparatus and the transfer function and unloader provided with the transfer function in front of the reducing chamber. CONSTITUTION:A reduction chamber 1 consists of reducing gas feeder, inert gas feeder or treating/circulating apparatus and shield door 11 which is used when a waste gas treating apparatus is connected as required. In front of the reduction chamber 1, equipped are a loader 21 provided with the transfer function, a middle platform 23 provided with a feeding/taking out apparatus and the transfer function and an unloader 24 provided with the transfer function. The inert gas feeder is connected to the middle platform 23. Shielding means are provided at the inlet and back parts of the loader 21, and the front part and the outlet of the unloader 24 to prevent mixing. This facilitates the automatization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a "halo" method by forming a copper oxide fine concavo-convex film on the surface of a copper foil of an inner layer board for a multilayer printed wiring board and subjecting it to vapor phase reduction for use in multilayer lamination molding. Or a novel inner layer plate vapor phase batch reduction apparatus which is preferably used for producing a multilayer plate substantially free of "pink ring".

[0002]

2. Description of the Related Art Multi-layer printed wiring boards are mainly manufactured by (a). Mass lamination method and (b). Pin lamination method, which are printed wiring boards for inner layers (hereinafter referred to as "inner layer boards"). It is manufactured, and the inner layer board, prepreg and copper foil or single-sided copper clad laminate is combined to form a multi-layered laminate to form a multilayer board made of copper foil on both sides, which is manufactured by processes such as through hole processing and outer layer printed wiring processing. ing.

In this multilayer printed board, a method of using a copper foil whose both surfaces are preliminarily roughened in order to improve the multi-layered adhesive strength of the inner layer board; after forming a printed wiring network for the inner layer ,. A method of forming a copper oxide fine concavo-convex film on the surface of a copper foil with an oxidizing treatment aqueous solution ,. A method of treating the copper foil surface with a silane coupling agent or an organic titanate coupling agent is known. Conventionally, from the viewpoint of adhesiveness and economical efficiency, usually, after forming a printed wiring network for the inner layer on a copper clad laminate having a glossy surface, it is treated with an oxidizing alkaline aqueous solution to give a brown or black copper oxide fine uneven film. What is formed is used.

However, this copper oxide fine uneven film, particularly cupric oxide, is easily dissolved in an acidic aqueous solution such as hydrochloric acid or sulfuric acid, and is brittle. For this reason, small holes are made in the laminated multilayer board, and during the through-hole plating step or electroless plating or the subsequent electroplating step, the copper oxide fine uneven film exposed on the hole wall is sequentially turned inward. A so-called "halo" or "pink ring" is generated which is attacked by the acid solution, and there is a drawback that causes deterioration of the reliability of the printed wiring board such as insulation.

As a method for preventing the halo or pink ring which occurs when this brown or black copper oxide fine uneven film is used. A method of reducing the copper oxide fine uneven film on the surface of the copper foil obtained in the above step with an aqueous solution of a reducing agent to change it to cuprous oxide or metallic copper (Japanese Patent Laid-Open No. 56-153797, etc.) is disclosed. These methods can achieve a practical level of adhesive strength, but require a new liquid-phase reduction treatment step, and the adhesive strength is lower than that of a brown or black copper oxide fine uneven film. Therefore, it is necessary to make the reducing conditions extremely strict to obtain an adhesive strength that can be put to practical use. Further, there is a variation in the effect of preventing the "pink ring" from occurring, and a new problem of waste liquid treatment of the reducing agent aqueous solution occurs.

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have performed a reduction treatment on a copper oxide fine uneven film that has been subjected to a brown or black oxidation treatment, and there is no variation in the effect of preventing "pink rings", and there is little decrease in adhesive strength. There was no such problem, and a thorough study was made on a method that does not cause a new problem of waste liquid treatment.

As a result, the vapor phase reduction method was completed, and Japanese Patent Application No. 2-
Patent applications were filed as 199210, 2-277884, 2-277885, and 2-284203. However, the industrial practice of these inventions generally requires the handling of reducing gases, which are relatively unfamiliar in the art. From this point of view, there will be no air contamination in the reduction chamber (system), no gas leakage into the atmosphere, no danger of explosion, etc., and an automated device not only in terms of safety but also productivity. As a result of studying from the viewpoint that it is preferable, it is possible to automate the loading and unloading of the inner layer plate into the reduction chamber, further, there is no fear of gas leakage, and it is possible to further reduce the consumption of inert gas. After finding out what was necessary, the present invention was completed.

[0008]

That is, the present invention is to form a brown or black copper oxide fine uneven film by chemically oxidizing a copper foil surface of an inner layer board for a multilayer printed wiring board on which a printed wiring network is formed. After that, a vapor phase batch reduction apparatus for the inner layer plate that reduces the copper oxide fine uneven film in a reducing gas presence atmosphere, which is a reducing gas supply apparatus, an inert gas supply or treatment circulation apparatus, and if necessary. A reduction chamber having a shielding door to which a waste gas treatment device is connected, a supply table having a transfer function at the front of the reduction chamber, an input / output machine, an intermediate table having a transfer function, and an extraction table having a transfer function. It is a vapor phase batch reduction apparatus for the inner layer plate provided.

Further, according to the present invention, an inert gas supply device is connected to the intermediate base, an inlet of the supply base, a rear part of the supply base and a front part of the extraction base, and an outlet of the extraction base. A vapor phase batch reduction apparatus for a multilayer plate, characterized in that each of them is provided with a shielding means for preventing gas mixture.

The multilayer printed wiring board of the present invention uses an inner layer board obtained by oxidizing a copper foil surface to form a brown or black copper oxide fine concavo-convex film and subjecting this to vapor phase reduction.
Any prepreg used for multi-layer adhesion, a prepreg for forming an outer layer, and a laminate material such as a copper foil or a single-sided copper-clad laminate and a laminate molding method can be used as long as they are in a conventionally known concept. And is not particularly limited.

Further, a method of forming a copper foil surface of a copper foil of the inner layer plate on a brown or black copper oxide fine concavo-convex film--a fine concavo-convex film consisting of copper oxide submicron-order needles, wedges, ono, anchors, etc. Is generally known, and usually, after polishing or washing the copper foil surface of the inner layer plate, pre-etching (soft etching, chemical polishing) with an aqueous solution of copper chloride or ammonium persulfate, and oxidizing treatment with an alkaline oxidizing aqueous solution. by.

Among the known methods for forming a brown or black copper oxide fine unevenness film, a specific method which has been put into practical use is the obtained copper oxide fine unevenness film as it is, or these are reduced in a liquid phase. It is a condition under which a good adhesive force is obtained when treated and multilayer-laminated.

However, in the present invention, since the copper oxide fine unevenness film which has not been used in the conventional vapor phase reduction is used, the copper oxide fine unevenness film or the surface reduced in the liquid phase is
The best adhesive strength does not always become the best after reduction. As a copper oxide fine uneven film, the unevenness is large compared to the conventional one and the adhesive strength is poor because it is brittle, or when copper oxide is partly dropped off when laminating the laminate set, it adheres to the non-printed wiring part. Even if a trouble that causes contamination is generated, if the metal copper is reduced, the cause of such trouble disappears, so that it can be used as one showing higher adhesive strength. Further, in the present invention, by adding a platinum group catalyst before the reduction,
The reduction temperature can be lowered and the speed can be increased.

The inner layer plate in which the copper oxide fine concavo-convex film is formed on the copper foil described above is usually subjected to reduction treatment in the vapor phase batch reduction apparatus of the present invention in a form of being housed in a rack or the like. The vapor phase batch reduction apparatus of the present invention comprises a reduction chamber and a unit for loading / unloading the inner layer plate into / from the reduction chamber, and is provided with a control device for automatically controlling these as appropriate. More specifically, the reducing chamber is connected with a reducing gas supply device, an inert gas supply device or a circulation treatment device, and is further provided with an internal circulation device, a waste gas treatment device and the like as appropriate.

Further, the loading / unloading section for the inner layer plate to / from the reduction chamber has a supply table having a transfer function such as a roller and a belt conveyor, a loading / unloading section for a forklift and the like, and an intermediate table having a transfer function and a transfer function. Consists of a take-out stand, which reduces the amount of inert gas used, and
To avoid mixing of reducing gas and air,
It is provided with a movable shielding means such as a gas flow curtain and a wall. It can be a batch continuous or batch apparatus, and the operating pressure of these can be appropriately changed from reduced pressure to increased pressure, but from the viewpoint of easiness of operation, it is performed at around normal pressure.

The gas-phase batch reduction in the reduction chamber is carried out in an atmosphere containing a reducing gas. The atmosphere in which a reducing gas is present is an atmosphere in which a reducing gas such as hydrogen or carbon monoxide or any other gasifiable reducing compound such as hydrazine gas is present, and is usually diluted with a non-oxidizing gas. However, it is a gas phase atmosphere that enables operation at normal pressure. Further, the temperature, time, etc. of the gas phase reduction are appropriately selected depending on the type and amount of the reducing gas used (absolute pressure or partial pressure), whether or not a white metal catalyst is applied.

When a gas having a small reducing power at room temperature, such as hydrogen, is used, it is in the range of 80 ° C to 300 ° C, particularly 100 to 16 ° C.
At 0 ℃, especially the upper limit temperature is selected from the range of temperature considering the dimensional stability of the inner layer plate to be treated, the treatment time 1 minute ~
The time is suitably selected from the range of 24 hours, preferably 10 minutes to 3 hours, and it is preferable to add a white metal catalyst to lower the temperature and increase the speed.

In the case of a compound having a reducing ability even at room temperature such as hydrazine, it is usually in the range of 160 ° C. to room temperature, preferably 140 ° C. to 60 ° C., particularly 120 ° C. to 80 ° C., treatment time.
It is appropriately selected from the range of 30 seconds to 3 hours, preferably 1 to 60 minutes, and particularly 2 to 30 minutes. In this case, too, reduction can be carried out at high speed by adding a platinum catalyst.

Particularly when hydrazine gas is used, even if the atmosphere itself is in the gas phase, hydrazine gas is condensed on the copper oxide fine uneven film or water produced by the reduction reaction is not vaporized to form a liquid film. Then, the reduction reaction may proceed in the liquid film, and in the case of the high-speed or low-temperature reduction reaction, the liquid film formation is likely to occur. However, when the liquid film is formed, the copper element is moved, and the fine unevenness of the copper oxide fine uneven film is destroyed, resulting in a reducing film having no adhesive force.

Therefore, the partial pressure of hydrazine gas is not more than 50%, preferably 20% of the saturated vapor pressure at the processing temperature.
Below, especially below 5%, and the partial pressure of water vapor is
50% or less, preferably 30% or less, particularly 10% or less of the saturated vapor pressure at the treatment temperature is set to a low value, and vaporization is promoted so that water produced in the reduction reaction does not condense to form a liquid phase. It is preferable to perform air blowing and stirring for this purpose. The air velocity in this blast stirring is 0.01 m / sec or more, preferably 0.1 m / sec or more, and since it is usually carried out with a large number of inner layer plates stored in a rack, the air velocity between the inner layer plates is within this range. As described above, it is preferable to use internal stirring or blowing together.

When hydrazine is used,
Since a large amount of non-oxidizing gas will be used as a medium, it is particularly preferable to recycle it if necessary and to circulate it. It is preferable to use it so that the partial pressure is 10 mmHg or less.

[0022]

EXAMPLES Next, an example of the case where the gas phase batch reduction is continuously carried out under substantially atmospheric pressure will be described with reference to FIG. 1 below, focusing on the reduction operation. In Fig. 1, at the start of operation, the inlet / outlet part (2) of the inner layer plate, which is easily sealed except for the inlet and outlet by the reducing chamber (1) and the shielding wall (3), is replaced by nitrogen from the inert gas supply device. To do.

Then, a large number of inner layer boards are housed in a rack, a copper oxide fine uneven film is formed on a printed wiring copper foil of the inner layer board, and a plurality of dried racks are opened with a simple door (26) and a supply table ( 21) Put on and close the door (26) while introducing nitrogen gas. The simple door (27) at the rear of the supply table (21) is opened, the rack is transferred onto the intermediate table (23) having a transfer function, and the simple door (27) is closed. Open the door (11) of the return chamber (1), load the rack into the return chamber (1) with the forklift (22), and then lift the forklift (22).
Returns to its original position and closes the door (11) of the reduction chamber (1) while introducing nitrogen gas into the intermediate stage (23). The rack to be returned next is supplied on the supply table (21) in the same manner as above until the return is completed, and the rack for which return has been completed similarly opens the simple door (29) during this time. It is taken out.

The reducing gas from the reducing gas supply device is
Appropriately, dilute to a predetermined concentration with an inert gas from an inert gas supply device or a circulation treatment device, and put it into the reduction chamber (1).
Internal circulation is performed by the internal circulation device (12), and part of the gas is treated by the waste gas treatment device to perform gas phase batch reduction.

After the reduction is completed, the door (11) of the reduction chamber (1) is introduced while introducing nitrogen gas into the intermediate stand (23) or the forklift (22).
Open the rack, take out the reduced rack from the reduction chamber (1) with the forklift (22), and remove the rack (24) at the front of the take-out stand (24).
Open, transfer from the intermediate stand (23) to the take-out stand (24),
8) Close.

Then, by carrying out the reduction reaction by introducing the rack previously put on standby on the supply table (21) into the reduction chamber in the same manner as described above, the gas phase reduction by the gas phase batch reduction apparatus of the present invention is carried out. carry out. In FIG. 1, the reducing gas supply device, the inert gas supply device or the circulation processing device, the waste gas processing device, and the control devices used for the reduction process are omitted.

Further, since the vapor phase reduction treatment described above is carried out at a predetermined temperature, time, etc., the inner layer plate supply table (21)
To the outside and taking out from the take-out stand (24) to the outside,
Automatic control of these procedures is easy and preferred. Further, in FIG. 1, by adopting a structure in which a gas flow curtain is also used when opening and closing the reduction chamber door (11) and the like,
Presence of inert gas and reducing gas Minimize the inflow and outflow of gas between the chambers filled with inert gas, and oxidize by utilizing the residence time of the rack on the supply table (21). Drying of the treated inner layer board or supply table (2
It is also possible to connect 1) in series with a drier and supply a dried rack onto a supply table.

More preferably, the fine concavo-convex film reduced to metallic copper has finer concavo-convex as compared with the copper oxide fine concavo-convex film. Therefore, particularly fine irregularities are likely to be oxidized due to their huge specific surface area, and are likely to be deteriorated in adhesive strength by being transformed into copper oxide during storage.

Therefore, it is preferable to carry out a rust preventive treatment in order to prevent oxidation and facilitate storage. As this method, there is a method of treating with an ordinary rust preventive aqueous solution immediately after taking out and drying, but in the present invention, gradual oxidation without using a liquid is particularly preferable.

Gradual oxidation is usually carried out with an oxygen partial pressure of several mmHg.
It can be easily carried out by treating at a temperature of about 20 ° C or higher, and after taking out from the reducing chamber, a trace amount of oxygen is mixed before the temperature of the inner layer plate lowers in the taking-out part where there is substantially no reducing gas. By doing so, it becomes feasible. In the case of the apparatus shown in FIG. 1, this deoxidation can be carried out by waiting in a predetermined atmosphere until it is taken out to the outside on the take-out table (24).

As described above, the inner layer plate which has been subjected to the vapor phase reduction by the apparatus of the present invention is usually used as it is for the multilayer lamination molding to be a multilayer shield plate having copper foil on both sides, and then punched and polished. After being subjected to desmear treatment, electroless plating, electrolytic plating, etc., a halo-free multilayer printed wiring board is obtained by forming printed wiring patterns on both surfaces.

Incidentally, the main cause of the "pink ring" being confirmed even when the inner layer plate reduced to copper by the vapor phase reduction of the present invention is confirmed is the storage state of the laminated material and the multilayered lamination molding condition. , Drilling conditions, and other causes.

[0033]

As described above, from the detailed description and examples, the vapor phase batch reduction apparatus of the present invention is extremely simple and easy to automate. The gas-phase reduction of the present invention does not substantially cause waste liquid treatment problems such as liquid-phase reduction. For example, waste gas from the reducing device can be guided to the catalytic combustion device, and unreacted reducing gas can be easily converted into carbon dioxide gas or water. Further, hydrazine and the like can be easily removed or recovered from the waste gas by cooling and condensation or absorption into water, and can be reused.

Further, the necessary and sufficient amount of the reducing gas required in the present invention is, for example, the average thickness of the copper oxide fine uneven film 2
We made an overestimation of μm and set the processing area to 5,000 m ² .
When using hydrogen, it is about 18 Nm ³ . The amount of gas used industrially is extremely small, and it is easy to supply this gas while generating a required amount on the spot by a hydrogen generator by a commercially available ammonia decomposition.

In the case of hydrazine, entrapped hydrazine can be preferably used, and the amount thereof present in the reducing system is preferably in the range of 0.1 to 15 mmHg. From this point,
For example, it is only necessary to allow this amount of hydrazine gas to exist in nitrogen gas at normal pressure, and it is possible to operate with a gas partial pressure far below the explosion limit, and no explosion etc. will occur even if it leaks. Conditions can be used.

Moreover, the multilayer printed board using the inner layer board subjected to the vapor phase reduction of the present invention has a brown or black copper oxide as a plating solution in the through-hole plating step for electrically connecting the printed wirings of the multilayer board. The occurrence of "halos", which tend to melt and melt and cause defects such as electrical shorts, is greatly reduced or eliminated altogether. The above is the vapor phase batch reducing apparatus for an inner layer board of the present invention, which is capable of producing a multilayer printed wiring board having excellent reliability with good productivity and no pollution, and has an extremely high industrial significance. is there.

[0037]

[Brief description of drawings]

FIG. 1 is a plan view centering on a transfer part of an inner layer plate in a vapor phase batch reduction apparatus of the present invention.

[Explanation of symbols]

The reference numerals are respectively: 1: reduction chamber, 2: loading / unloading part of inner layer plate, 3: shield wall, 11: reduction chamber door, 12: internal circulation device, 21: supply stand, 22: forklift, 23: intermediate stand, 2
4: Take-out stand, 26, 27, 28, 29: Shows a simple door.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuo Tanaka 6-1, 1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo factory (72) Inventor Takeo Kanaoka 2-5 Marunouchi, Chiyoda-ku, Tokyo No. 2 Sanryo Gas Chemical Co., Ltd. (72) Inventor Norio Sayama 2-5-2 Marunouchi, Chiyoda-ku, Tokyo Sanryo Gas Chemical Co., Ltd.

Claims (3)

[Claims] 1. A copper foil surface of an inner layer board for a multilayer printed wiring board on which a printed wiring network is formed is chemically oxidized to form a brown or black copper oxide fine concavo-convex film, and then in a reducing gas atmosphere. A vapor phase batch reducing apparatus for an inner layer plate for reducing the copper oxide fine uneven film, the shielding comprising a reducing gas supply apparatus, an inert gas supply or processing circulation apparatus, and a waste gas processing apparatus as necessary. Vapor phase batch reduction of the inner layer plate provided with a reduction chamber with a door, a supply table having a transfer function at the front of the reduction chamber, an intermediate table having a loading / unloading machine and a transfer function, and an extraction table having a transfer function apparatus 2. The vapor phase batch reducing apparatus for an inner layer plate according to claim 1, wherein an inert gas supply device is connected to the intermediate base portion. 3. The inner layer plate according to claim 2, wherein the inlet of the supply table, the rear part of the supply table, the front part of the extraction table, and the outlet of the extraction table are provided with shielding means for preventing gas mixture. Gas phase batch reduction device