JPH0715147A - Method and device for forming blind hole of multilayer wiring board - Google Patents

Abstract

PURPOSE:To provide a method and device for forming a blind holes easily regardless of the scattering in the thickness of each layer and entire part of a multilayer wiring board. CONSTITUTION:A conductive drill 10, a control part 26 for controlling the conductive drill, electrical connection members 22a-22d with the conductive layer of a multilayer wiring board 2, and a power supply 20 and current detectors A1-A4 for detecting electrical continuity between the connection member and the conductive drill 10 are provided. The control part 26 stops the advance of the conductive drill 10 from the upper-surface side of the multilayer wiring board 2 based on the current detection signal from the current detectors A1-A4 which are electrically connected to the targeted conductive layer of the multilayer wiring board 2, thus forming blind holes up to the conductive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a semi-through hole in a multilayer wiring board. In particular, the present invention can easily and accurately form a semi-through hole that can penetrate at least one insulating layer from one surface side of a multilayer wiring board to a desired conductive layer even if there are variations in the thicknesses of the conductive layer, the insulating layer and the whole. A method for forming and an apparatus therefor.

[0002]

2. Description of the Related Art In recent years,
As surface mounting in which electronic components are directly mounted on one side or both sides of a wiring board has become popular, a multilayer wiring board having a conductive layer inside has been widely used. In this multilayer wiring board, conductive layers are laminated in multiple layers with an insulating layer interposed therebetween, each conductive layer is formed into a desired wiring pattern before the lamination, and at least a proper position is provided for conducting a plurality of conductive layers. It can be obtained by forming a through hole penetrating one insulating layer and forming a conductive film on the inner surface of the through hole.

In the case of a multi-layer wiring board, unlike the case of a conventional single-layer wiring board, in addition to through through holes penetrating the entire board, an internal conductive layer is connected to another internal conductive layer or a surface conductive layer. Therefore, it is necessary to form a semi-through hole that penetrates at least one insulating layer. In the case of forming the semi-through through hole, in the case of forming the through through hole, it is sufficient to simply specify the in-plane position of the substrate and advance the drill for sufficient distance drilling to penetrate the entire substrate. Differently, it is necessary to precisely control the depth of penetration of each semi-through hole.

Conventionally, in order to form this semi-through hole, as shown in FIG. 5, the position in the substrate surface and the traveling distance of the drill 10 'are designated by the control unit 20' for each through hole. I was working on it.

By the way, a multilayer wiring board is manufactured by laminating conductive layers via an insulating layer. However, the thickness accuracy is not always strict enough due to the difference in processing conditions in the manufacturing process. The thickness of each conductive layer, the thickness of each insulating layer, and the thickness of the entire substrate may vary depending on the in-plane position of the same substrate or may vary between different substrates.

Therefore, as shown in FIG. 6, for example, the distance D is based on the upper surface of the substrate 2 having the conductive layers 4a to 4f.
Even if you push Kiri 10 'downward by ₁ ,
In (a), a semi-penetrating through hole up to the fifth conductive layer 4e is formed, but in (b), the fourth conductive layer 4d.
Only a half-through through hole up to is formed. Further, for example, even when the drill is advanced downward to the distance D ₂ with the lower surface of the substrate 2 as a reference, in (a), a half-through through hole to the fifth conductive layer 4e is formed,
In (c), only half-through holes up to the fourth conductive layer 4d are formed.

As described above, in the conventional method of forming a through hole, it is often impossible to properly form a through hole if there is a variation in the thickness of each layer of the multilayer wiring board or the entire thickness, and the yield is improved. It was difficult.

In order to avoid such a disadvantage, the accuracy of the manufacturing process of the multilayer wiring board should be improved.
This has the disadvantage of significantly increasing costs.

Therefore, in view of the problems of the prior art as described above, the present invention easily and reliably forms an appropriate semi-through hole even if there are variations in the thickness of each layer of the multilayer wiring board or the entire thickness. It is an object of the present invention to provide a method and an apparatus for forming a semi-through hole that can be formed.

[0010]

According to the present invention, in order to achieve the above-mentioned objects, a conductive chip is made to progress from one side of the multilayer wiring board, and the conductive chip has the purpose of the multilayer wiring board. A conductive layer is electrically connected to the conductive layer to stop the progress of the conductive drill, to form a semi-through through hole to the target conductive layer, Semi-through hole forming method,
Will be provided.

Further, according to the present invention, in order to achieve the above-mentioned objects, a conductive edge, a control means for controlling the conductive edge, and an electrical connection means for connecting the conductive layer of the multilayer wiring board. A detecting means for detecting electrical continuity between the connecting means and the conductive drill, the control means based on a detection signal from the detecting means from one side of the multilayer wiring board. Provided is a semi-through hole forming device for a multilayer wiring board, which is characterized in that the progress of conductive drilling is stopped.

In one aspect of the present invention, the detection means includes a power source and means for applying a voltage between the conductive drill and the connecting means, and the conductive drill and the The electrical continuity is detected by detecting a current flowing between the connecting means.

In another aspect of the present invention, a plurality of the connection means are provided, and the control means selects one of the detection signals relating to the connection means, and based on the selected detection signal. The progress of the conductive drill is stopped.

In still another aspect of the present invention, a plurality of the connecting means are provided, and a selecting means for selecting a voltage application between the conductive drill and each of the connecting means is provided, and the control is performed. The means also control the selection means.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view of an embodiment of a method of forming a half through hole according to the present invention and an apparatus for carrying out the method. In FIG. 1, reference numeral 2 is a horizontally arranged multilayer wiring board. FIG. 2 shows a partially enlarged view of the multilayer wiring board. The substrate 2 has a plurality of conductive layers 4a, 4
b, 4c, 4d, 4e, 4f and insulating layers 6a, 6b, 6c, 6d, 6e interposed between the conductive layers.

In FIG. 1, 10 is a conductive tool as a tool for forming a through hole, and 11 is a supporting / driving portion thereof. The drill 10 is moved and rotated in the vertical direction (Z direction) by the support / drive unit 11. The supporting / driving unit 11 is held by a holding member 12 so that the drill 10 faces downward. The holding member is arranged along a pair of parallel guide members 14a, 14b in one direction in the horizontal plane (that is, Y
Direction), and this movement is made by the interaction between the driving means in the holding member 12 and the guide member 14a. Mounting members 1 are provided on both ends of the guide members 14a and 14b.
6a and 16b are attached. These mounting members are movable along a pair of parallel guide members 18a, 18b in one direction in the horizontal plane (that is, the X direction), and this movement is such that the drive means in the mounting member 16a and the guide member 18a move with respect to each other. Done by action.

On the other hand, 20 is a DC power source, one electrode of which is electrically connected to the conductive drill 10.
Further, 22a, 22b, 22c, 22d are connecting members for electrically connecting to the respective internal conductive layers 4b, 4c, 4d, 4e of the substrate 2, and these connecting members and the other electrode of the power source 20 are Current detectors A ₁ , A ₂ , A ₃ , respectively
It is connected via A ₄ . Connection members 22a, 22
b, 22c, 22d and the internal conductive layers 4b, 4c, 4d,
The electrical connection with 4e can be made, for example, by exposing a part of each internal conductive layer and soldering it as shown in FIG.

In FIG. 1, reference numeral 26 is a control unit, which controls the rotation and Z direction movement of the conductive drill 10, the Y direction movement of the holding member 12, and the X direction of the mounting member 16a. Control movement. Position signals are sent from these controlled units to the control unit 26. The control unit 26 also receives detection signals from the current detectors A _{1 to} A ₄ . Then, the control unit 26 can select any _{one of the} current detectors A _{1 to} A ₄ . This selection can be done by activating only one of the detectors, or by activating all detectors and the controller itself selecting one of the input detection signals. You can also

Work data is input to the control unit 26 in advance. This data includes two-dimensional coordinates (X coordinate and Y coordinate) indicating the position in the substrate surface for each half-through hole to be formed, and the tip of the half-through hole (that is, the deepest part of the half-through hole). And a code for identifying the conductive layer to be reached.

First, the controller 26 issues a movement command to the holding member 12 and the mounting member 16a so as to move the drill 10 to the position designated by the two-dimensional coordinates. Next, a command is issued from the control unit 26 to the drill support / driving unit 11 so as to rotate the drill and move it downward in the Z direction, and at the same time, it is electrically connected to the conductive layer specified by the above code. A current detector is selected. Eventually,
The perforations 10 start to be formed on the upper surface of the substrate 2, and the depth of the perforations gradually increases as the perforations progress. Then, when the energization detection signal is input to the control unit 26 from the selected current detector, the control unit issues a command to the drill support / driving unit 11 to stop drilling in the Z direction downward,
Next, the drill retreats upward in the Z direction. Similar steps are performed for the other semi-through holes.

FIGS. 3A to 3E are diagrams showing a state in which the downward movement of the drill 10 in the Z direction is stopped when the semi-through hole is formed as described above. (A) ~
In (d), the top conductive layer 4a and the internal conductive layers 4b, 4c,
4d and 4e are respectively formed with semi-through holes, and in (e), semi-through holes are formed to connect the upper surface conductive layer 4a and both of the two internal conductive layers 4b and 4d. R.

According to the above embodiment, even if the total thickness of the substrate 2, the thickness of each conductive layer, and the thickness of each insulating layer varies, the progress of the drill 10 is surely stopped when the target conductive layer is reached. Therefore, the desired semi-penetrating through hole can be easily and surely formed.

FIG. 4 is a diagram showing a modification of the above embodiment. In this figure, the same members as those in FIG. 1 are designated by the same reference numerals. In this modification, only one current detector A is used, and the conduction selection switch 30 is provided between the detector A and the connection members 22a to 22d. The selection of the switch is made by the control unit 26, whereby the electrical conduction between the drill 10 and the desired conductive layer of the substrate can be detected.

[0025]

As described above in detail, according to the present invention, it is possible to easily and surely form an appropriate semi-through hole even if there is a variation in each layer thickness or overall thickness of the multilayer wiring board. , The yield is improved, and the reliability is dramatically improved. Therefore, the precision of the manufacturing process of the multilayer wiring board is not strict, and the cost is not increased. Further, conventionally, the depth data was instructed point by point for each through hole, but in the present invention, since it is only necessary to specify the conductive layer,
The data is greatly simplified and the control becomes easier.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a method of forming a half through hole according to the present invention and an apparatus for carrying out the method.

FIG. 2 is a partially enlarged view showing a multilayer wiring board.

FIG. 3 is a diagram showing a state in which the progress of drilling when forming a semi-through hole is stopped.

FIG. 4 is a diagram showing a modification of the embodiment of FIG.

FIG. 5 is an explanatory diagram of a conventional method of forming a semi-through hole.

FIG. 6 is a diagram showing a state in which the progress of drilling is stopped when a semi-through hole is formed by a conventional method.

[Explanation of symbols]

2 Multilayer wiring board 4a-4f Conductive layer 6a, 6b, 6c, 6d, 6e Insulating layer 10 Conductive drill 11 Drilling support / driving part 12 Holding member 14a, 14b Guide member 16a, 16b Mounting member 18a, 148 Guide member 20 DC power 22a~22d electrical connection member 26 controller 30 conducts selection switch A, A ₁ ~A ₄ current detector

Claims (5)

[Claims] 1. A conductive chip is advanced from one side of a multilayer wiring board, and when the conductive chip is electrically connected to a target conductive layer of the multilayer wiring board, the conductive chip is advanced. And forming a semi-penetrating through hole to the target conductive layer, the method for forming a semi-penetrating through hole in a multilayer wiring board. 2. A conductive drill, control means for controlling the conductive drill, electrical connection means for the conductive layer of the multilayer wiring board, and electrical continuity between the connection means and the conductive drill. A multi-layer wiring, wherein the control means stops the progress of the conductive drill from one side of the multi-layer wiring board based on a detection signal from the detection means. Substrate semi-through hole forming device. 3. The detecting means comprises a power source and means for applying a voltage between the conductive drill and the connecting means, and between the conductive drill and the connecting means. The semi-through hole forming device for a multilayer wiring board according to claim 2, wherein the electrical conduction is detected by detecting a flowing current. 4. A plurality of the connection means are provided, and the control means selects one of the detection signals relating to each of the connection means, and advances the conductive drill based on the selected detection signal. The half-penetrating through-hole forming device for a multilayer wiring board according to claim 2 or 3, wherein the device is stopped. 5. A plurality of the connection means are provided, and a selection means for selecting a voltage application between the conductive drill and each of the connection means is provided, and the control means also controls the selection means. The semi-through hole forming device for a multilayer wiring board according to claim 3 or 4, characterized in that.