JPH06112659A - Multilayer wiring board processor and processing method - Google Patents

Abstract

PURPOSE:To enable such counterboring as to expose the wiring layer of a multilayer wiring board completely without cutting it too much. CONSTITUTION:A processor comprises a processing tool 304, a rotating motor 303, a control motor 302, a power supply circuit 306 for giving voltage to the tool, a contact detecting circuit 308 for detecting that the tool has contacted with the objective lower-layer wiring, a detection lead wire 309, and a control circuit 310 for outputting a control signal to a variety of motors. When the tool shaves the insulating part of a board and reaches the specified lower layer and continuity is made, the control circuit 310 generates a control signal by the signal from a contact detection circuit 308, and stops the sending of the processing tool 304 or rotates it reversely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a processing method for carrying out a counter boring process for disposing a power element in a lower wiring layer in order to improve heat dissipation performance in a multilayer wiring board.

[0002]

2. Description of the Related Art Conventionally, there has been known a hybrid electronic circuit in which an electronic circuit handling a small current and a power element handling a large current are mounted on the same metal base. In this case, the power element is arranged on the metal base via the insulating film in order to improve the heat dissipation performance, and the part where the power element is not formed has a multilayer wiring for improving the mounting density of the electronic circuit. Is being formed.

To form a multilayer wiring on a metal base,
A copper foil having a thickness of about 100 μm is adhered on a metal base via an insulating film, and after etching into a predetermined pattern, an insulating film is formed by printing on the patterned copper foil. A second wiring layer is formed on the surface by copper plating. However, in this method, since the thickness of the copper foil is large, voids are generated at the edges of the copper foil when the insulating film is formed by printing, and since the second wiring layer is formed by plating, the second wiring layer is formed. There is a problem that the thickness cannot be increased and the plating solution remains between the insulating film and the second wiring layer.

On the other hand, in a wiring board in which copper foil is adhered to both sides of an insulating layer, the copper foil is patterned into a predetermined shape to form a through hole, and the through hole is plated so that the upper and lower wiring layers are electrically connected. After that, there is also a method of joining this wiring board to a metal base via an insulating film. In this method, the thickness of the wiring layer can be freely determined, and the problems such as voids caused by the former method can be avoided.

[0005]

However, in order to dispose the power element on the wiring layer closest to the metal base, the wiring substrate in the area where the power element is disposed is partially removed, that is,
It is necessary to spot face to expose the bottom wiring layer closest to the metal base.

However, when the spot boring process is performed by a drill, since the substrate thickness is originally thin and the thickness of the multilayer wiring substrate varies, if the feed of the machining tool is fixed to a constant value, the lower layer is not always required. The wiring is not always completely exposed,
On the contrary, there was a problem that it was too deeply spotted and the wiring was destroyed. As described above, conventionally, it has been very difficult to perform counterboring in a multilayer wiring board with high precision and efficiency.

The present invention has been made to solve the above problems, and its purpose is to provide a multilayer wiring board,
It is possible to carry out a spot facing process such that a predetermined wiring layer can be completely exposed without cutting too much.

[0008]

A structure of the invention for solving the above problems is to partially send a tool to a multilayer wiring board in which a plurality of wiring layers are formed in multiple layers with an insulating layer interposed therebetween. In a processing device for spot facing the insulating layer to expose a part of a predetermined wiring layer below, a power feeding means for applying a voltage between the tool and the predetermined wiring layer, a tool and the predetermined wiring layer. That is, there is provided a conduction detecting means for detecting conduction with and a control means for controlling the feeding of the tool according to the output of the conduction detecting means.

According to another aspect of the invention, in a method for spot-boring a multilayer wiring board, a voltage is applied between the tool and a predetermined wiring layer to detect conduction between the tool and the predetermined wiring layer,
The feature is that the tool feed is decelerated / stopped / retracted according to the detection of the continuity.

[0010]

Function: A voltage is applied between the tool and the predetermined wiring layer to be exposed by the power feeding means. In this state, the tool is sent in the direction of the multi-layer wiring board to carry out the drilling process. Continuity detection means for detecting contact between the tool and the predetermined wiring layer by detecting voltage or current is connected to the predetermined wiring layer,
When the tool reaches the predetermined wiring layer, the conduction detecting means detects the conduction between the tool and the predetermined wiring layer. A signal is output from the continuity detecting means when the tool comes into contact with the predetermined wiring layer, but the feeding of the tool is stopped in response to this signal. Therefore, the predetermined wiring layer can be completely exposed without breaking. It should be noted that the surface layer such as the blackening treatment film formed on the predetermined wiring layer can be properly removed by delaying the feeding of the tool for a predetermined time when the tool comes into contact with the predetermined wiring layer. It is possible to arrange the power element and the like at this counterbore position with good electrical conductivity.

[0011]

According to the present invention, a conduction detecting means for detecting conduction between the tool and the predetermined wiring layer by applying a voltage between the tool and the predetermined wiring layer and detecting the voltage or the current appearing in the predetermined wiring layer. Is provided, and the feeding of the tool is stopped according to the output of the detecting means. Therefore,
The machining stop position of the tool can be accurately grasped, and the predetermined wiring layer can be completely exposed without breaking.

[0012]

EXAMPLES The present invention will be described below based on a specific example. (1) Structure of Multilayer Wiring Board As shown in FIG.
It is bonded to the upper surface by an insulating layer 103 which is an adhesive.
The multilayer wiring board 102 is an insulating layer 10 made of glass epoxy.
5, and an upper surface wiring layer 104 and a lower surface wiring layer 106 which are formed in a predetermined pattern on the upper surface and the lower surface of the insulating layer 105 and which are joined with an adhesive. The upper surface wiring layer 104 and the lower surface wiring layer 106 are electrically connected by a copper thin film 108 plated in a through hole 107 formed at a predetermined position. The counterbore processing apparatus of the apparatus of this embodiment is for boring the counterbore portion 109 and soldering the power element to the exposed lower surface wiring layer 106. This metal-based multilayer wiring board is shown in FIG.
As shown in the sectional view of (1), wiring copper foils 201 and 202 are laminated at least on the front and back sides with an insulating layer 203 interposed between them. After making it into a desired wiring pattern, a through hole 204 is attached. After being formed, a through hole 204 is plated to form a structure as shown in FIG. 2 (2), and a metal base 206 is bonded to the metal base 206 with an adhesive 205 as shown in FIG. 2 (3). It is made by insulating and pasting together. The copper foil of FIG. 2 (1) may be provided with a blackening treatment film 212 in order to improve the adhesiveness with the insulating layer 210, as shown in FIG. 2 (4). .

(2) Structure of Counterbore Processing Apparatus A simple embodiment apparatus for performing the above-mentioned counterbore processing is shown in FIG.
Shown in. The processing equipment is the processing tool 304 and the board fixing base 301.
And a rotary motor 303 for rotating the tool, the rotary motor
A control motor 302 for moving the motor, a power supply circuit 306 for applying a voltage to the tool, a power supply line 307, a contact detection circuit 308 for detecting that the tool contacts the target lower layer wiring, and a predetermined lower layer wiring. Detection lead 309, which receives the detection signal
Control circuit 310 for outputting a control signal to the data, control signal line 311,
It consists of 312. The control signal line 311 is connected to the control motor 302, and the control signal line 312 is connected to the tool rotation motor 303.

FIG. 4 shows a specific example of the power supply circuit and the contact detection circuit of FIG. 3, where 410 is the power supply circuit and 420 is the contact detection circuit.
The power supply circuit 410 applies a potential to the drill 402 from the low voltage DC power supply 413 via the brush 411 and the slip ring 412. The power feeding method may be a non-contact type such as an induction coil.
From the lower wiring section 405 to be exposed on the substrate 401 to the lead wire 40
Pull out 6 and input to contact detection circuit 420. The contact detection signal is the terminal voltage of the input resistor 423, and the comparator 42
Set to the inverting input terminal of 1. The divided voltage is input to the non-inverting input terminal. The output of the comparator 421 is connected to the signal delay circuit 422.

FIG. 5 shows an embodiment of the control circuit, in which the detection signal is connected to the input terminal 508, and the transistor 50 receives the detection signal.
2 works and activates relay 503. The contact 504 of the relay changeover switch is connected to the control motor 506, and the contact 505 of the normally close is connected to the rotary motor 507 of the tool. FIG. 6 is an operation chart of the embodiment shown in FIGS. Since the machining is not limited to the spot facing, the embodiment of the apparatus can be made as complicated as possible, but the basic system is as described above.

(3) Operation of counterbore processing device In FIG. 4, the target substrate to be processed is the processing table 30 shown in FIG.
Fix to 1 and position as desired. Turning on the main switch (self-holding relay switch) 509 shown in FIG. 5 causes the drill 402 to rotate and descend. When the drill 402 scrapes the insulating portion 403 of the substrate and reaches the predetermined lower layer wiring 405 to cause conduction ((a) in FIG. 6), an electric potential is generated in the detection lead wire 406 and the output signal of the comparator 421 is output. It is inverted ((b) of FIG. 6). The signal delay circuit 422 receives the signal and
The blackening treatment film 212 in (4) is removed to generate a contact detection signal 426 which is set to have an optimum time delay in order to sufficiently expose the predetermined lower layer wiring 405 ((c) in FIG. 6). .

In the control circuit 501 of FIG. 5, the signal delay circuit 422
When the signal is received from the transistor 502, the transistor 502 is turned on and the relay 503 is activated ((d) of FIG. 6). By this relay operation, the relay contact 505 is turned off and the rotation of the drill is stopped. Also, the relay contact 504 switches,
When the motor 506 rotates in the reverse direction, the drill 402 rises and stops at the limiter switch 510.

(4) Effects of Counterbore Processing Apparatus According to the present invention, it is possible to efficiently realize lower layer wiring exposure by counterboring, which has not been realized so far in the manufacture of a multilayer base wiring board on a metal base. In circuits,
It has become possible to achieve higher density and higher reliability of devices.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a multilayer wiring board bonded on a metal base processed by a spot facing device according to an embodiment of the present invention.

2 is a cross-sectional view of a multilayer wiring board showing a manufacturing process of the multilayer wiring board shown in FIG.

FIG. 3 is a block diagram showing a configuration of a spot facing device according to an embodiment of the present invention.

FIG. 4 is a circuit diagram showing a power supply circuit and a contact detection circuit in the spot facing device shown in FIG.

5 is a circuit diagram showing a control circuit in the spot facing device shown in FIG.

6 is a timing chart showing the operation of the spot facing device shown in FIG.

[Explanation of symbols]

 101 Metal Base 102 Multilayer Wiring Board 103 Insulation Adhesive Layer 105 Insulation Layer such as Glass Epoxy Board 109 Counterbore Target Area 206 Metal Base 211 Copper Foil on Board Wiring Layer 212 Blackening Treatment Film 304 Processing Tool 305 Worked Board 410 Power supply circuit 420 Contact detection circuit 501 Control circuit 508 Control input terminal

Claims (2)

[Claims] 1. A multi-layered wiring board, in which a plurality of wiring layers are formed in multiple layers with an insulating layer interposed, and a tool is sent to partially scoop the insulating layer to form a part of a lower predetermined wiring layer. In a machining device for performing a spot facing process to expose the, a power feeding means for applying a voltage between the tool and the predetermined wiring layer, a conduction detection means for detecting conduction between the tool and the predetermined wiring layer, A multilayer wiring board processing apparatus comprising: a control unit that controls the feed of the tool according to the output of the continuity detection unit. 2. A multi-layer wiring board having a plurality of wiring layers formed in multiple layers with an insulating layer interposed, and a tool is sent to partially scoop the insulating layer to form a part of a lower predetermined wiring layer. In the method of performing the counterbore processing to expose the, by applying a voltage between the tool and the predetermined wiring layer, to detect the conduction between the tool and the predetermined wiring layer, depending on the detection of conduction, the tool Slows down / stops the feed of
A counterbore processing method for a multilayer wiring board, which is characterized by retreating.