JPH10190243A - Device for multi-layer printed interconnection board lamination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove resin and oxide on the surface of low-resistance metal particles and also to allow, microscopically, welding of a wiring layer to a via hole conductor, by providing a pair of electrodes so as to directly contact to the upper and lower surfaces of a to-be-processed object which is pressurized from both above and below, and applying pulse current to the pair of electrodes. SOLUTION: Between pressurized punches 2 and 3, a to-be-processed object A comprising plural wiring boards where a wiring layer is assigned in an insulation layer comprising an organic resin is provided, and to-be-processed object A, a pressure of 20-100kg/cm<2> is applied from both above and below with a pressure applying means comprising a hydraulic press 4 and a control unit 5. Then, between the to-be-processed object A and the pressurized pushes 2 and 3, a pair of electrode plates 6 and 7 is provided to directly contact to the upper and lower surfaces of to-be-processed object A, and to the contacted to-be-processed object A, such pulse current as under specified condition controlled with the control unit 5 is applied from a pulse power source 8. Thereby, reliability of a wiring board is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device housing having a wiring layer mainly composed of a low-resistance metal such as copper and a through-hole conductor filled with a metal paste on the surface of an insulating layer containing an organic resin. The present invention relates to a laminating apparatus used for producing a multilayer wiring board suitable for a package or the like.

[0002]

2. Description of the Related Art At present, a multilayer printed wiring board is prepared by bonding a copper foil to a surface of a flat plate containing an organic resin called a prepreg and etching the copper foil to form a fine circuit to produce a plurality of wiring boards. After laminating a plurality of wiring boards, a hole is drilled for a through hole at a desired position by a microdrill, and a metal is attached to the inner wall of the hole by a plating method or the like to connect between wiring layers. .

However, since the through holes penetrate through the insulating layer, the number of through holes increases as the number of stacked layers increases, and there is a problem that a space required for wiring cannot be secured. On the other hand, there is a strong demand for multilayered printed wiring boards and finer wiring because of the lighter and thinner electronic devices. Therefore, in response to the demand for multilayer printed circuit boards, finer wiring, and higher precision, a technology has been developed to fill a through-hole with a metal paste containing a metal powder or the like and then laminate the same to produce a multilayer wiring board. ing. Such a via-hole conductor is called an IVH (interstitial via hole) or a blind via hole.

[0004]

It is desirable that these via-hole conductors have a small electric resistance, but the paste necessarily contains an organic resin in order to improve fluidity and printability. In addition, there is a problem that the resistance value is higher than that of a conventional through hole formed by ordinary metal plating. For this reason, after printing the metal paste or filling the via holes, the resin component is thermally decomposed, the printed wiring layer is densified by pressing, and the printed wiring layer is energized and heated. Various improvements have been made.

In such a conventional method, as a laminating apparatus for producing a multilayer wiring board, a wiring layer having a metallized layer formed on the surface of an insulating layer is aligned,
It is placed between a pair of pressurizing punches, and pressure is applied from above and below, and the thermosetting resin in the insulating layer is heat-cured by a heater installed outside to thermally cure the thermosetting resin. I was In addition, the energization process is performed by applying a voltage to the stacked body through an electrode.

However, it has not been possible to completely remove resin, dirt, and the like even in the wiring layer of the multilayer wiring board obtained in this manner. Further, even if the resin component can be removed, it is not possible to remove an oxide film or the like inevitably present on the surface of the metal particles in the paste. Even if the resistance of the wiring layer is reduced, it is 7 × 10 ⁻⁴ Ω−. At most, it is difficult to reduce the resistance of the wiring layer, especially the via-hole conductor.

When the via-hole conductor is formed by filling a metal paste, there is another problem that the connection between the wiring layer disposed on the surface and the via-hole conductor is weakened.
If the connection is weak, cracks occur inside the via-hole conductor when a temperature cycle of low temperature and high temperature is applied, and the connection portion with the surface wiring layer peels off.

Accordingly, the present invention provides a multilayer printed wiring capable of forming a low-resistance wiring layer even when at least a part of the wiring layer is formed by using a metal paste in manufacturing a multilayer wiring board. An object of the present invention is to provide an apparatus for stacking plates.

[0009]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have conducted printing with a metal paste containing an organic resin and a low-resistance metal such as copper powder or the like, In stacking a plurality of wiring boards each having a wiring layer formed by filling a metal paste, a pressure is applied from above and below, and simultaneously, a pulse current is applied to an object to be processed through a pair of electrodes. In addition to removing the resin and oxides on the surface of the low-resistance metal particles that prevented electrical conduction at the same time, it was possible to microscopically weld the wiring layer and the via-hole conductor, and found that the reliability of the wiring board could be significantly improved. It has been found that this makes it possible to form a highly reliable wiring layer that can meet the demands for ultra-fine and precise multilayer printed wiring boards.

That is, the printed wiring board laminating apparatus of the present invention is a laminating apparatus for pressure-laminating an object to be processed comprising a plurality of wiring boards having a wiring layer disposed on an insulating layer containing at least an organic resin. Pressing means for pressing the object from above and below, a pair of electrodes arranged to directly contact the upper and lower surfaces of the object, and a pulse current for applying a pulse current to the electrodes. And applying means.

The pulse current applying means may have a voltage of 1 to 200 V and a pulse width of 1 to 100 V between the metal pressure plates.
0 ms, a pulse current of 1 to 500 A / cm ² can be applied, and in addition to the above configuration,
A temperature control unit for controlling the object to be processed to a predetermined temperature is provided, and all or a part of the wiring layer is formed of a metal paste containing a metal powder and an organic resin. It is characterized by the following.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic layout diagram showing an example of a multilayer printed wiring board laminating apparatus according to the present invention. According to the laminating apparatus 1 of FIG. 1, first, the pressure application including the pressure punches 2 and 3, the hydraulic press 4 for applying pressure between the pressure punches 2 and 3, and the control unit 5 capable of controlling the pressure. Means. A workpiece A composed of a plurality of wiring boards having a wiring layer disposed on an insulating layer containing at least an organic resin is disposed between the pressure punches 2 and 3, and a predetermined pressure is applied from above and below by this pressure applying means. Pressure is applied. By this pressure applying means, the object A to be processed is 1 to 200 kgf /
A pressure of ² cm ² , preferably 20 to 100 kg / cm ² is applied, and the pressure control means is desirably able to arbitrarily control the pressurizing speed in order to prevent air bubbles from remaining inside the processing target A.

The laminating apparatus 1 shown in FIG. 1 has a pair of electrode plates 6 arranged so as to be in direct contact with the upper and lower surfaces of the object to apply a predetermined pulse current to the object. , 7 and a pulse power source 8 connected to the electrode plates 6, 7
And a pulse current applying means composed of a control unit 5 for controlling them. The electrode plates 6 and 7 are provided between the workpiece A and the pressure punches 2 and 3 and directly contact the upper and lower surfaces of the workpiece. Then, the pair of electrode plates 6,
Numeral 7 is connected to a pulse power source 8 so that a pulse current of a predetermined condition controlled by the control unit 5 can be applied to the workpiece A that is in direct contact with the electrode plates 6 and 7.

By applying the pulse current to the object to be processed, the paste is applied to a wiring layer formed on the object to be processed, particularly a surface wiring layer formed by applying a metal paste comprising a metal powder and an organic resin and / or via holes. The resin, the oxide film, etc. existing between the metal powders in the via hole conductor formed by filling the via hole conductor can be removed, and the electrical connection is more reliably achieved by the so-called welding action between the surface wiring layer and the via hole conductor. This can reduce the resistance of the wiring layer and improve long-term stability.

According to this pulse current applying means, it is desirable that a pulse current can be applied to the object to be processed A under the conditions of a voltage of 1 to 200 V, an energizing time of one pulse of 3 seconds or less, and a pulse interval of 3 seconds or less. It is. This is because if the voltage is less than 1 V, the effect of lowering the resistance is small, and if it exceeds 200 V, heat is partially generated and the insulating layer may be damaged. Further, if the energizing time of one pulse exceeds 3 seconds, the processing time for lowering the resistance becomes long, and if the pulse interval is 3 seconds or more, the processing time becomes long and is not practical. Desirably, the energizing time of one pulse and the pulse interval are each 0.5 seconds or less, and the volume resistivity of the via hole conductor formed by filling the metal paste can be reduced to 1 × 10 ⁻⁴ Ω-cm or less, Optimally, if the energizing time of one pulse and the pulse interval are 0.02 to 0.1 second, 2 × 10 ^-5 is further obtained.
Ω-cm or less is achieved. Also, a suitable pulse current value is 50 to 5000 A per 100 cm ² of the substrate.

As a pulse current to be applied, a sine wave or the like is used, but a rectangular wave is most effective. Further, the pulse power supply 8 is preferably a DC pulse power supply.

A rectangular wave is more likely to cause discharge between particles and has a higher surface cleaning effect than a sine wave, and a direct current is less likely to adhere to the once cleaned particle surface than an alternating current. That's why.

The pressure punches 2 and 3 are desirably housed in a vacuum processing chamber 9 in order to control the atmosphere during pressurization. A gas inlet 10 and a gas outlet 11 are provided to reduce the surrounding atmosphere to a reduced pressure or vacuum or a non-oxidizing gas atmosphere such as an inert gas such as argon or nitrogen. Connected to vacuum processing chamber 9
The inside is evacuated to control the pressure, and an inert gas such as argon or a non-oxidizing gas such as nitrogen is introduced from the gas inlet 10 as necessary. In order to prevent air bubbles from remaining inside the object, it depends on the object to be processed.
Keep the minimum pressure up to about 0 ° C and heat in vacuum.
It is preferable to introduce a gas such as argon or nitrogen while gradually pressurizing from about 0 ° C.

The processing chamber 9 is provided with a temperature control means capable of controlling the temperature of the object to be processed in a range from room temperature to 400 ° C. if necessary. For example, as shown in FIG.
Hot plates 13, 14 arranged between the electrode plates 6, 7;
It comprises a hot plate heating / cooling unit 15 for heating or cooling the hot plates 13 and 14 to control the temperature and a control unit 5 for controlling them. A heating medium or a cooling medium is circulated through the heating plates 13 and 14 through a heating plate heating / cooling unit 15 to be controlled at a predetermined temperature.

In the case of heating by this temperature control means, a heating medium is circulated through the above-mentioned heating plates 13 and 14, but as another method, a heater is built in the heating plates 13 and 14 to heat the heater. Is also good. Also, depending on the conditions of the pulse current application, the temperature of the object to be processed may rise abnormally. In such a case, the object to be processed A is circulated by circulating a cooling medium through the hot plates 13 and 14. Can be cooled.
The heating temperature for the object to be treated A is preferably about 100 to 200 ° C., but when a resin having high heat resistance such as polyimide is used as the resin contained in the object to be treated A, heating to about 400 ° C. There is also.

The temperature control method is not limited to the use of the above-mentioned heating plates 13 and 14, but may be energization heating by the pair of electrode plates 6 and 7. In the energization heating, the object can be heated by applying a predetermined voltage to the object through the electrode plates 6 and 7 and energizing the wiring layer, and at the same time, further reducing the resistance of the wiring layer. Can be achieved. This energization process is performed at a voltage of 10 to 100.
V, DC or AC with a current of 3 to 50 A per 100 cm ^{2 of} substrate may be used.
It is desirable to be in the range of 00 ° C. If the heating temperature at this time is higher than 300 ° C., the resin having high heat resistance that forms the insulating layer is decomposed, and if it is lower than 100 ° C., the effect of further lowering the resistance is small. By this electric heating, the bond between the metal particles is strengthened, and the resistance of the wiring layer can be reduced.

The energization heating process can be performed simultaneously with the above-described pressurizing process or the pulse current applying process, or can be performed after the pressurizing process or the pulse current applying process. In the case of performing simultaneously with the pulse current application process, specifically, when a waveform obtained by combining a DC pulse current and a DC current, that is, a current in which the upper part of the DC current waveform is a rectangular wave is applied to the wiring layer, The action of energizing heating,
It is possible to simultaneously add a discharge welding action by applying a pulse current.

In order to grasp the state of the wiring layer and stabilize the electrical characteristics when a pulse current or a DC voltage is applied to the object to be processed, the voltage between the electrode plates 6 and 7 is reduced when the pulse current and / or the DC current is applied. Is preferably measured by the product resistance measuring unit 16, and the application of the pulse current and / or the direct current is feedback-controlled based on the resistance change. Thus, variation in the resistance value of the object can be reduced.

In the laminating apparatus shown in FIG. 1, the pressure punches 2, 3 and the electrodes 6, 7 and the hot plates 13, 14 are provided separately, but at least the surfaces of the pressure punches 2, 3 are electrically conductive. Or by providing a mechanism for circulating a heater, heat medium, cooling medium, etc.
May be provided with a function as an electrode and / or a hot plate.

In the present invention, as an object to be processed by this laminating apparatus, for example, as shown in FIGS. 2A and 2B, a surface layer and an internal wiring layer are formed on an insulating layer 17 containing at least an organic resin as a wiring layer. It is a plurality of wiring boards on which the layer 18 and the via-hole conductor 19 are provided. As the organic resin forming the insulating layer, a thermosetting resin, a heat-resistant thermoplastic resin having a high melting point, a composition including these resins, or the like is usually used.

The thermosetting resin is not particularly limited as long as it is a thermosetting resin having electrical properties, heat resistance, and mechanical strength as an insulating material. For example, a phenol resin, an epoxy resin, Polyimide resin, fluororesin, polyphenylene ether resin, bismailide triazine resin, urea resin, melamine resin, silicone resin, polyurethane resin, unsaturated polyester resin, allyl resin, and the like can be used.

In the above-mentioned insulating layer, an inorganic filler can be compounded with an organic resin in order to increase the strength of the insulating layer or the entire wiring board. As the inorganic filler compounded with the organic resin, Si
O ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , AlN, S
iC, BaTiO ₃ , SrTiO ₃ , zeolite, Ca
Known materials such as TiO ₃ and aluminum borate can be used, and a sheet (prepreg) obtained by impregnating a resin into a glass-clothed aramid nonwoven fabric may be used. In the composite material of the organic resin and the inorganic filler, the volume ratio of the organic resin: the inorganic filler is 15:
It is appropriate that the composite is formed in a ratio of 85 to 50:50.

Wiring layer 1 disposed on insulating layer 17
Numerals 8 and 19 form conductive paths for electrically connecting electronic components such as semiconductor elements mounted on a wiring board to each other or to the outside. For example, a group of copper, silver, aluminum, and gold is formed. It is preferable to include a low-resistance metal mainly composed of at least one or two or more alloys selected from the group consisting of copper, and particularly, copper or an alloy containing copper is most desirable. In some cases, a high-resistance metal such as a Ni—Cr alloy may be mixed or alloyed as the conductor composition for adjusting the resistance of the circuit. Further, for lowering the resistance of the wiring layer, a metal having a lower melting point than the low-resistance metal, for example,
A low melting point metal such as solder or tin may be contained in the metal component in the conductor composition at a ratio of 2 to 20% by weight.

The laminating apparatus of the present invention is characterized in that the electric resistance between the conductive particles can be reduced by applying a pulse current. Therefore, this laminating apparatus is suitable for a wiring board formed of a metal paste containing a metal powder and an organic resin, particularly, a wiring board having a via-hole conductor or a through-hole conductor formed of a metal paste containing a metal powder and an organic resin. It is most effective to do so. In the metal paste used here, the metal powder in the paste preferably has an average particle size of 0.5 to 50 μm. If the average particle size is smaller than 0.5 μm, the contact resistance between the metal powders tends to increase and the resistance of the via-hole conductor tends to increase, and if the average particle size exceeds 50 μm, it tends to be difficult to reduce the resistance of the via-hole conductor. It is in.

The metal paste contains, in addition to the above metals, an organic resin for bonding the metal powders. As this organic resin, the same resin as the organic resin constituting the insulating layer is used. This organic resin is
The metal powders are bonded together in a state where they are in contact with each other, and also function to adhere the low-resistance metal to the insulating layer. This organic resin is 0.1 to 40% by volume, particularly 0.3 to 30% by volume in the metal paste.
Is desirably contained at a ratio of If the amount of the resin is less than 0.1% by volume, it is difficult to bond the metal powders firmly, and it is difficult to firmly bond the low-resistance metal to the insulating layer. When you cross,
This is because the resin is interposed between the metal powders, making it difficult to bring the powders into sufficient contact with each other, and increasing the resistance of the via-hole conductor.

A wiring layer such as a via-hole conductor and a through-hole conductor formed by the above-mentioned metal paste is formed by an aggregate of the above-mentioned metal powders. There is an oxide film upon reaction. The organic resin for bonding such powders prevents conduction between the metal powders.

When a plurality of wiring boards having a wiring layer made of the above-mentioned metal paste are laminated by the laminating apparatus of the present invention, contact between adjacent metal powders in the paste is performed by applying a pulse current at the time of pressurization. The parts are discharge-welded, whereby the particles are directly connected to each other without an oxide film or an organic resin between the particles, so that a low-resistance wiring layer is formed.

Further, the wiring layers 18 formed on the object to be processed,
In order for the pulse current to be applied to the entirety, a wiring layer connected to the internal wiring layer is required on the surface in contact with the pair of pressure plates as shown in FIG. If there is no wiring layer, the dummy wirings 20, 2
It is desirable to design the circuit so that the pulse current is applied to all the wiring layers in the wiring board by providing a pulse current 1 between the dummy wirings. Then, if necessary, the dummy wiring may be removed after the pulse current application processing.

[0034]

EXAMPLE A prepreg of a bismaleimide triazine resin and a glass cloth was used as an insulating layer to a thickness of 100 μm.
m of a semi-cured insulating sheet was formed. Then, a wiring layer having a thickness of 12 μm was formed on the surface of the insulating layer using a copper foil. Further, a through-hole having a diameter of 0.1 mm is partially formed, and 90% by volume of copper powder having an average particle diameter of 8 μm in the hole and 0.5% by volume of an organic resin made of cellulose are used as solid components. -A copper paste prepared by mixing octanol as a solvent was filled and dried.

Next, eight wiring boards prepared as described above were prepared, aligned, superposed, and set between pressurizing plates in the laminating apparatus of the present invention. And
A pulse current was applied between the wiring layer formed on the outermost surface of the multilayer wiring board and the wiring layer formed on the lowermost layer under the conditions shown in Table 1. The pulse current was applied while applying a pressure of 50 kg / cm ² between a pair of metal pressure plates. Further, a heat treatment was performed on some of the substrates by applying a voltage of 80 V. Sample Nos. 12 and 13
For, the pulse current and the energization heating were performed simultaneously.
The specific resistance of the wiring layer was measured for the obtained multilayer wiring board, and the results are shown in Table 1.

In the above copper paste, a silver-coated copper powder having an average particle size of 5 μm and an average particle size of 3 μm were used instead of the copper powder.
Wiring boards were prepared in exactly the same manner as above except that silver powder of μm and silver-copper alloy powder having an average particle diameter of 4 μm were used, and the results are shown in Samples Nos. 20 to 24 in Table 1.

[0037]

[Table 1]

According to the results shown in Table 1, in Sample No. 1 which was not treated at all, disconnection of the wiring layer due to penetration of the resin of the insulating layer at the boundary between the via-hole conductor and the wiring layer on the surface was confirmed. When a pulse current was applied using the laminating apparatus of the present invention, there was no resin intrusion or disconnection.

In particular, there is no disconnection in the range of 3 to 1000 msec for both the energizing time and pulse interval of one pulse, and optimally, the resistance of the via-hole conductor is reduced to 6 × 10 ⁻⁶ Ω-cm or less in the range of 10 to 100 msec. Could be reduced. When the structure of the wiring layer of the sample to which the pulse current was applied was observed, it was confirmed that the contact portion between the via-hole conductor and the wiring layer on the surface was in a finely welded state.

Further, in the laminating apparatus of the present invention, in addition to the pulse current, the samples Nos.
Then, no disconnection was recognized in any case.

[0041]

As described above in detail, according to the printed wiring board laminating apparatus of the present invention, a multilayer printed wiring board having a via-hole conductor formed by a conductive paste containing a low-resistance metal such as copper powder and an organic resin. By applying a pulse current to the upper and lower pressing plates of the laminating apparatus for laminating
We found that it was possible to microscopically weld the wiring pattern and via-hole conductor at the same time as removing the resin and oxide on the surface of the low-resistance metal particles that were preventing electrical conduction, thereby significantly improving the reliability of the wiring board. This makes it possible to manufacture a highly reliable multilayer wiring board that can meet the demand for ultra-fine and precise multilayer printed circuit boards.

[Brief description of the drawings]

FIG. 1 is a schematic layout diagram for explaining a multilayer printed wiring board laminating apparatus of the present invention.

FIG. 2 is a diagram for explaining a wiring board processed by the laminating apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminating apparatus 2, 3 Pressure punch 4 Hydraulic press 5 Control unit 6, 7 Electrode plate 8 Pulse power supply 9 Vacuum processing chamber 10 Gas inlet 11 Gas outlet 12 Vacuum pump 13, 14 Hot plate 15 Hot plate heating / cooling unit 16 Product resistance measurement unit 17 Insulating layer 18 Surface and internal wiring layer 19 Via-hole conductor 20, 21 Dummy wiring A Workpiece

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Riichi Sasamori 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute

Claims (4)

[Claims] 1. A laminating apparatus for press-stacking an object to be processed consisting of a plurality of wiring boards having a wiring layer disposed on an insulating layer containing at least an organic resin, wherein the object to be processed is applied from above and below. Pressure means for applying pressure, a pair of electrodes arranged so as to directly contact the upper and lower surfaces of the object to be processed, and pulse current applying means for applying a pulse current to the electrodes. Multilayer printed wiring board laminating apparatus. 2. The apparatus according to claim 1, wherein said pulse current applying means has a voltage of 1 to 20.
0 V, pulse width 1 to 1000 msec, conduction current 1 to 500
The multilayer printed wiring board laminating apparatus according to claim 1, wherein a pulse current of A / cm ² can be applied. 3. The multilayer printed wiring board laminating apparatus according to claim 1, further comprising temperature control means for controlling the temperature of the object to be processed to a predetermined temperature. 4. The multilayer printed wiring board laminating apparatus according to claim 1, wherein all or a part of said wiring layer is formed by a metal paste containing a metal powder and an organic resin.