JPH09300172A - Manufacturing method of printed wiring board - Google Patents

Abstract

(57) Abstract: The present invention relates to a printed wiring board that constitutes an electronic device or the like, and a printed wiring board that can not only greatly reduce the processing cost but also greatly improve the electrical connection reliability. It is intended to provide a manufacturing method. When drilling a printed wiring board, a liquefied gas 5 is supplied to a drilling portion of the printed wiring board to perform drilling while cooling the printed wiring board, thereby increasing the number of drill hits. It is possible to obtain a good inner wall of the hole, and it is possible to prevent a disconnection defect of a through hole, a dielectric breakdown defect due to migration and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a printed wiring board used for mounting semiconductors such as CPUs and memories, other electronic components such as resistors and capacitors, and chip components.

[0002]

2. Description of the Related Art Recently, due to further miniaturization and thinning of portable electronic equipment, the degree of integration of chip parts such as semiconductors, resistors, capacitors, etc. has become very dense. The printed wiring board must also have a high density. A multilayer printed wiring board has been devised to cope with such a situation. This multilayer printed wiring board is composed of a plurality of boards (inner layer circuit boards).
A conductor circuit is previously formed on the substrate and these substrates are bonded to each other so as to cope with mounting of highly integrated electronic components.

In such a multilayer printed wiring board, it is necessary to electrically connect the layers. Usually, a through hole is provided to electrically connect the layers, and a current flows through the hole to make an electrical connection.

Various methods such as a plating method and a conductive paste method have been proposed and implemented as the method of providing the through holes. As a general manufacturing method for each method, first, holes are formed by an NC drill machine or the like, and then plating is performed in the holes or a conductive paste is put into the holes to establish conduction between layers.

FIG. 6 shows a conventional NC drill machine. A table 6 is placed on a table 8 so that it can move back and forth. An arm 9 is mounted on the table 8, and a spindle motor 10 for fixing the drill 1 with a drill chuck 3 is mounted on the arm 9. The spindle motor 10 can move the arm 9 left and right. Substrate 2 placed on table 6
The table 6 is moved forward and backward, and the spindle motor is moved left and right to determine the processing position and perform processing.

[0006]

However, when a printed wiring board is mounted with heat by a soldering process or the like to mount a component, it is very difficult to ensure continuity reliability because the plating in the through hole is cut off at that time. It is generally known to be difficult. This is because the inner wall of the through hole has a rough surface and the plating thickness is thin. In addition, if the inner wall of the through hole is rough and the conductive paste is used for conduction, the conductive paste or the like may enter the inside of the base material and migrate (create a conduction path where there should be no conduction path and cause dielectric breakdown). It is known that the inner wall roughness of the hole needs to be controlled very strictly because of the occurrence of phenomena such as (causing). Therefore, it is necessary to maintain the surface roughness of the inner wall for drilling in a good state.
Therefore, it is the current situation that drills are set to be replaced very early in the process. Therefore, there has been a problem that the drill cost becomes very high and the cost of the printed wiring board is raised.

The present invention solves such conventional problems,
The life of the drill can be extended and the cost of the drill can be reduced, and at the same time, the surface roughness of the inner wall of the hole can be maintained in a good state, and the printed wiring board that does not cause defective through-hole disconnection or dielectric breakdown due to migration is inexpensive. It is to provide a method that can be made.

[0008]

In order to solve the above problems, the method for manufacturing a printed wiring board according to the present invention supplies a liquefied gas to a hole processing part of a printed wiring board when the printed wiring board is drilled. It is characterized by drilling holes while cooling the wiring board, and is characterized by supplying liquefied gas to the drill when drilling the printed wiring board and drilling while cooling the drill. It is a thing.

Further, when the printed wiring board is drilled, liquefied gas is supplied to the vicinity of the drilled portion of the printed wiring board to cool the printed wiring board and the drill while drilling.

Further, when the printed wiring board is drilled, the table on which the printed wiring board is mounted is cooled and the printed wiring board is drilled while cooling the printed wiring board. It is characterized in that the drill chucking portion is cooled at the time of processing and the drill is drilled while cooling.

Further, it is characterized in that liquid nitrogen is used as the liquefied gas for cooling.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) (FIG. 1) is a side view for explaining an apparatus of a method for manufacturing a printed wiring board according to Embodiment 1 of the present invention. This figure shows a substrate processing part, and the other parts of the device are the same as the conventional device shown in FIG.

As shown in FIG. 1, according to the method for manufacturing a printed wiring board of the present invention, a drill 1 is attached to a drill chuck 3 and a nozzle is formed so that a liquefied gas 5 is blown to the drill 1 when making a hole in a substrate 2. 4 are provided.

The inventor has found that there is a correlation between the drill temperature and the working state. It was discovered that the higher the drill temperature during drilling, the worse the working condition, and conversely, the lower the drill temperature, the better the working condition and the better the inner wall roughness of the hole. This is because when the drilling temperature is high, the melting point of the substrate material (usually glass or other fiber impregnated with epoxy resin, phenolic resin, etc.) exceeds the melting point when the drilling temperature is high, and the resin melts and the drill cutting edge This is because processing such that a phenomenon such as adhesion to the substrate does not occur and the substrate material is torn off is performed.

Therefore, the present invention has an object of processing at a temperature below the melting point of the resin by processing while cooling. The drill temperature is preferably 150 ° C. or lower during processing, and 100 ° C. or lower at the temperature when the drill is removed from the substrate. More preferably, the drill temperature during processing is 130
℃ or less, 80 ℃ as drill temperature when removed from the substrate
It is better to do the following. Further, in order to improve the working condition, the drill temperature is preferably 100 ° C. or lower, and the temperature when the drill is pulled out from the substrate is preferably 50 ° C. or lower.

In the method for manufacturing a printed wiring board of the present embodiment, the drill 1 is cooled while being cooled with liquid nitrogen 5 in order to lower the temperature in the vicinity of the processed portion in order to satisfy the above conditions. The temperature of the drill does not rise by cooling the drill directly. In this embodiment, a 1.6-layer-thick 6-layer substrate is processed. The diameter of the drill is 0.4 mm and the rotation speed is 80,000 rpm. Liquid nitrogen was used as the liquefied gas for cooling.

The reason why liquid nitrogen is used is that it is a liquid having a very low temperature of about −196 ° C. and has a high cooling effect and is relatively inexpensive in liquid gas. It is possible to use a coolant such as cutting oil or water instead of liquid gas, but liquid nitrogen is more likely to have a cooling effect because the temperature can be further lowered.

In this embodiment, a substrate having a thickness of 1.6 mm is used for processing, but it goes without saying that it can be applied to substrates of other sizes. The layer structure is not limited to six layers. Further, although liquid nitrogen was used for cooling, it goes without saying that other liquefied gases such as carbon dioxide gas and argon gas can also be applied.

(Embodiment 2) (FIG. 2) is a side view for explaining an apparatus of a method for manufacturing a printed wiring board according to Embodiment 2 of the present invention. This drawing shows the processed portion of the substrate, and the other parts of the device are the same as those of the conventional device shown in FIG.

As shown in FIG. 2, in the method for manufacturing a printed wiring board according to the present invention, the drill 1 is attached to the drill chuck 3 and the nozzle 4 is so arranged as to blow a liquefied gas onto the substrate 2 when making a hole in the substrate 2. It is provided.

The printed wiring board manufacturing method of this embodiment is similar to that of the first embodiment, in that the substrate 2 is cooled while being cooled with liquid nitrogen 5 so that the temperature of the working portion is not lowered and the temperature of the drill is not raised. is there. With such a configuration, the heat generated in the processed portion can be quickly removed through the substrate and the temperature of the processed portion can be prevented from rising. In this embodiment, a 1.6-layer thick 6-layer substrate is processed. The diameter of the drill is 0.4 mm and the rotation speed is 80,000 rpm.
Liquid nitrogen was used as the liquefied gas for cooling.

In this embodiment, a substrate having a thickness of 1.6 mm is used for processing, but it goes without saying that the substrate can be applied to other sizes. The layer structure is not limited to six layers. Further, although liquid nitrogen was used for cooling, it goes without saying that other liquefied gases such as carbon dioxide gas and argon gas can also be applied.

(Embodiment 3) (FIG. 3) is a side view for explaining an apparatus of a method for manufacturing a printed wiring board according to Embodiment 3 of the present invention. This drawing shows the processed portion of the substrate, and the other parts of the device are the same as those of the conventional device shown in FIG.

As shown in FIG. 3, according to the method for manufacturing a printed wiring board of the present invention, the drill 1 is attached to the drill chuck 3 and the metal table 6 supporting the substrate 2 when the substrate 2 is drilled is liquefied gas 5. The passage 7 is provided so as to be cooled by. Liquid nitrogen is flowing in the passage 7.

In the method for manufacturing a printed wiring board according to the present embodiment, the substrate 2 is held on a table cooled with liquid nitrogen 5 so that the temperature of the processed portion is not lowered and the temperature of the drill is not raised as in the first embodiment. It is to be processed. With such a configuration, the heat generated in the processed portion can be quickly removed to the table 6 side through the substrate 2 and the temperature of the processed portion can be prevented from rising. In the present embodiment, the 6 mm 1.6 mm thick
The layered substrate was processed. The diameter of the drill is 0.4 mm and the rotation speed is 80,000 rpm. Liquid nitrogen was used as the liquefied gas for cooling.

In this embodiment, a substrate having a thickness of 1.6 mm is used for processing, but it goes without saying that it can be applied to substrates of other sizes. The layer structure is not limited to six layers. Further, although liquid nitrogen was used for cooling, it goes without saying that other liquefied gases such as carbon dioxide gas and argon gas can also be applied. Further, it is preferable to use a table having good heat conduction such as metal, and the same effect can be obtained by using a table having good heat conduction other than metal.

(Embodiment 4) (FIG. 4) is a side view for explaining an apparatus of a method for manufacturing a printed wiring board according to Embodiment 4 of the present invention. This drawing shows the processed portion of the substrate, and the other parts of the device are the same as those of the conventional device shown in FIG.

As shown in FIG. 4, according to the method for manufacturing a printed wiring board of the present invention, the drill 1 is attached to the drill chuck 3, and when the substrate 2 is drilled, liquefied gas is applied to the cutting portions of the drill 1 and the substrate 2. Nozzle 4 is provided so as to spray.

In the method for manufacturing a printed wiring board according to the present embodiment, the processed portions of the drill 1 and the substrate 2 are cooled with liquid nitrogen 5 so that the temperature of the processed portion is lowered and the temperature of the drill is not raised as in the first embodiment. While processing. With such a configuration, the heat generated in the processed portion can be quickly removed to both sides of the drill 1 and the substrate 2, and the temperature of the processed portion can be prevented from being raised. In this embodiment, a 1.6-layer thick 6-layer substrate is processed. The diameter of the drill is 0.4 mm and the rotation speed is 80,000 rpm. Liquid nitrogen was used as the liquefied gas for cooling.

In this embodiment, a substrate having a thickness of 1.6 mm is used for processing, but it goes without saying that the substrate can be applied to substrates of other sizes. The layer structure is not limited to six layers. Further, although liquid nitrogen was used for cooling, it goes without saying that other liquefied gases such as carbon dioxide gas and argon gas can also be applied.

(Fifth Embodiment) (FIG. 5) is a side view for explaining an apparatus of a method for manufacturing a printed wiring board according to a fifth embodiment of the present invention. This drawing shows the processed portion of the substrate, and the other parts of the device are the same as those of the conventional device shown in FIG.

As shown in FIG. 5, in the method for manufacturing a printed wiring board according to the present invention, the drill 1 is attached to the drill chuck 3 and the nozzle 4 is formed so as to blow the liquefied gas to the drill chuck 3 when the substrate 2 is drilled. Is provided.

In the method for manufacturing a printed wiring board of this embodiment, the drill chuck 3 is cooled while being cooled by liquid nitrogen 5 so as not to raise the temperature of the drill and the temperature of the drill as in the case of the first embodiment. Is. With such a configuration, the heat generated in the processed portion is quickly removed to the drill chuck 3 side through the drill 1 and the temperature of the processed portion can be prevented from rising. In the present embodiment, the 6 mm 1.6 mm thick
The layered substrate was processed. The diameter of the drill is 0.4 mm and the rotation speed is 80,000 rpm. Liquid nitrogen was used as the liquefied gas for cooling.

In this embodiment, a substrate having a thickness of 1.6 mm is used for processing, but it goes without saying that it can be applied to substrates of other sizes. The layer structure is not limited to six layers. Further, although liquid nitrogen was used for cooling, it goes without saying that other liquefied gases such as carbon dioxide gas and argon gas can also be applied.

In the first to fifth embodiments, the substrate, the drill, the table, the drill chuck, etc. are cooled by spraying the liquefied gas with the nozzle and passing the liquefied gas through the passage provided in the table. Drill,
If the table and the drill chuck can be cooled, the same effect can be obtained by other methods.

Instead of the liquefied gas, another coolant (water,
The same effect can be obtained by using a high-pressure cooling gas, a solvent, a cutting fluid, etc.).

The same effect can be obtained even if the entire NC drill processing device is placed in a room kept at a low temperature for processing.

With the above-described structure, in the method for manufacturing a printed wiring board of the present invention, since it is possible to perform cutting while cooling the drill, the substrate, etc., it is possible to suppress the temperature rise of the cutting portion, extend the life of the drill, and reduce the drill cost. At the same time, the surface roughness of the inner wall of the hole can be maintained in a good state, and a printed wiring board that does not cause through-hole disconnection failure, migration failure, etc. can be manufactured at low cost.

(Comparative Example) A side view of an apparatus according to a conventional printed wiring board manufacturing method is shown in FIG. 6 for comparison with the embodiment of the present invention.

In the comparative example, 1.6 mm as in the embodiment.
A thick 6-layer substrate was processed. The diameter of the drill is 0.4 mm and the rotation speed is 80,000 rpm. Processing was performed without cooling with liquefied gas or the like.

In the embodiment and the comparative example of the present invention, the size of the substrate is 510 mm × 430 m, which is the same size.
Processing was performed with a size of m. The size of the NC drill machine is provided with a table on which a substrate can be placed, and the table size is about 600 mm × 500 mm.

Table 1 shows the relationship between the number of processing hits of holes and the surface roughness of the inner wall when the processing of this embodiment is performed.

[0044]

[Table 1]

As shown in (Table 1), it can be seen that in the processing method of the present embodiment, the deterioration of the inner wall roughness is small even if the number of processing hits is increased.

In the method for manufacturing a printed wiring board of the present invention,
Since it is possible to perform cutting while cooling the drill, substrate, etc., it is possible to suppress the temperature rise of the cutting part, extend the life of the drill and reduce the cost of the drill, and at the same time make the surface roughness of the inner wall of the hole good A printed wiring board which can be maintained and does not cause a through-hole disconnection defect or a dielectric breakdown defect due to migration can be manufactured at low cost.

[0047]

As described above, according to the method for manufacturing a printed wiring board of the present invention, since it is possible to perform cutting while forcibly cooling the drill, the substrate, the table supporting the substrate, etc., the temperature rise of the cutting portion can be prevented. It is possible to prevent the restraint substrate resin from melting and adhering to the cutting edge of the drill, and to extend the life hit number of the drill, which reduces the consumption cost of the drill and at the same time reduces the labor for replacement In addition to being able to down, it is possible to maintain the surface roughness of the inner wall of the hole in a good state, to prevent defects such as through-hole disconnection defects and dielectric breakdown defects due to migration, and greatly improve quality reliability. You can do it, and it will be possible to make it significantly cheaper.

[Brief description of drawings]

FIG. 1 is a side sectional view for explaining a method for manufacturing a printed wiring board according to an embodiment of the present invention.

FIG. 2 is a side view for explaining the method for manufacturing the printed wiring board according to the embodiment of the present invention.

FIG. 3 is a side view for explaining the method for manufacturing the printed wiring board according to the embodiment of the present invention.

FIG. 4 is a side view for explaining the method for manufacturing the printed wiring board according to the embodiment of the present invention.

FIG. 5 is a side view for explaining the method for manufacturing the printed wiring board according to the embodiment of the present invention.

FIG. 6 is a side view for explaining a conventional method for manufacturing a printed wiring board.

[Explanation of symbols]

 1 drill 2 substrate 3 drill chuck 4 nozzle 5 liquefied gas 6 table 7 passage

Claims (6)

[Claims] 1. A method for manufacturing a printed wiring board, which comprises supplying a liquefied gas to a hole drilling portion of the printed wiring board when drilling the printed wiring board, and drilling while cooling the printed wiring board. . 2. A method for manufacturing a printed wiring board, which comprises supplying a liquefied gas to a drill and drilling the drill while cooling the drill when the printed wiring board is drilled. 3. A printed wiring board characterized by supplying a liquefied gas to the vicinity of a drilled portion of the printed wiring board when drilling the printed wiring board, and drilling while cooling the printed wiring board and the drill. Manufacturing method. 4. A method for manufacturing a printed wiring board, which comprises: when drilling a printed wiring board, cooling a table on which the printed wiring board is mounted and drilling while cooling the printed wiring board. 5. A method for manufacturing a printed wiring board, which comprises: cooling a drill chucking portion when drilling a printed wiring board; and drilling while cooling the drill. 6. The method for manufacturing a printed wiring board according to claim 1, wherein liquid nitrogen is used as the liquefied gas.