JP2618492B2 - Thick film circuit direct drawing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for directly drawing a thick film circuit, and more specifically, a vertical direction from a reflecting surface using a height sensor for receiving light reflected from a circuit board. And a thick film circuit direct drawing method for drawing a thick film circuit pattern on a circuit board by obtaining distance data of a thick circuit.

[Prior art] The current hybrid IC has a high density, similar to a thin film IC.
Multilayering is required, and for this reason, a thick-film circuit forming technique of laminating a plurality of conductive patterns with an insulator interposed therebetween is used. Normally, a thick film circuit is drawn directly on a circuit board made of ceramic or the like placed at a predetermined position on an XY table according to a predetermined program by discharging conductive paste from nozzles to draw a predetermined circuit pattern Made using equipment.

When forming a thick-film circuit in this way, it is necessary to measure the exact height of the circuit board and then perform drawing. This height is measured using a height sensor,
In recent years, position sensing device PS has been able to easily and accurately detect and realize low cost.
A distance sensor using D (hereinafter, referred to as a position detecting element) is often used as a height sensor.

[Problem to be Solved by the Invention] When height data is obtained using such a height sensor, the light quantity change signal has a dull shape at the boundary from the circuit board to the circuit pattern. There is a problem that the measurement of the distance in the direction becomes inaccurate. For this reason, in the related art, the amount of reflected light is determined at the same time, and when the change in the amount of reflected light that occurs at the boundary from the circuit board to the circuit pattern is equal to or greater than a predetermined threshold value, it is determined to be the boundary. The height data at the boundary is corrected.

Normally, the amount of reflected light shows a different value depending on the type of conductor and the change with time. And the amount of reflected light generally decreases with time. Therefore, if the change in the amount of reflected light is detected with the fixed threshold value as described above, accurate height data cannot be obtained.

Accordingly, the present invention has been made to solve such a problem, and it is an object of the present invention to provide a method for directly drawing a thick film circuit capable of accurately measuring height data of a circuit board and drawing an accurate circuit pattern. As an issue.

[Means for Solving the Problems] In order to solve the above-described problems, the present invention uses a height sensor that receives reflected light from a circuit board to determine vertical distance data from a reflecting surface and attaches the data to the circuit board. In the thick film circuit direct drawing method for drawing a thick film circuit pattern, a predetermined threshold value is set from the sample reflected light amounts of the circuit board substrate and the drawing pattern, the reflected light amount from the circuit board is measured, and the reflected light amount is measured. Is determined to be a boundary when the threshold value is passed, and the distance data of the boundary is corrected by replacing the distance data with a distance data at a predetermined distance from the boundary, and drawing is performed according to the corrected distance data. Was adopted.

[Operation] According to such a method, the predetermined threshold value is set based on the sample reflection light amount of each of the circuit board base and the drawing pattern. However, a threshold value corresponding to the threshold value can be set, and distance data can be accurately corrected. The measurement of the sample reflected light amount of each of the circuit board substrate and the drawing pattern for setting the threshold value can be performed even during the drawing, but it is preferable to perform the measurement before the drawing and store the measurement data in the memory. Specifically, the threshold value is selected to be approximately the intermediate value between the sample reflected light amounts of the circuit board substrate and the circuit pattern. Further, if the decrease in the amount of reflected light in a spike shape during drawing is measured, the material of the pattern is determined to be a glass material, and the distance data obtained based on the amount of reflected light at this time is corrected. Correction of the distance data becomes possible.

EXAMPLES Hereinafter, the details of the present invention will be described based on examples shown in the drawings.

FIG. 1 shows a direct drawing apparatus used in the method of the present invention. In FIG. 1, reference numeral 1 denotes a circuit board made of ceramic or the like, which is moved in X and Y directions.
It is positioned at a predetermined position on the table 2. This substrate 1
The nozzle 3 of the ink pen 4 for discharging a paste forming a conductor and an insulator is arranged perpendicular to the XY table 2 and is moved via the motor 5 in the Z-axis direction perpendicular to the XY plane.

By numerically controlling the discharge of the paste from the nozzle 3 and the stop of the discharge, and the movement of the XY table 2 in the XY plane according to a predetermined program, various circuits as shown in FIG. Pattern film 8
Can be formed. At this time, the unevenness of the circuit board 1 is detected by the height sensor 6, and the height of the nozzle 3 is automatically controlled via the motor 5 along the Z-axis direction according to the detected height. The height sensor 6 is a position detecting element
Laser light emitted from a light source 12, such as a laser diode, is applied to the circuit board 1 via a condenser lens 13 and a polarizing filter 15, and reflected light from the circuit board is reflected by a polarizing filter 16 The light is condensed on the position detecting element 11 via the lens 14.

The position detecting element 11 generates different currents for the currents i1 and i2 obtained from both ends thereof, depending on where the laser light is focused. For example, when the pattern of the circuit board 1 is irradiated with laser light, the position detecting element 11
Current value at both ends when laser light is focused on the approximate center of
When i1 and i2 are equal and the light is reflected by a surface different from that of the substrate 1, the image points are different from each other.
A difference occurs between i1 and i2. In this case, the distance in the Z direction is proportional to (i1-i2) / (i1 + i2).
Is known to be a value proportional to (i1 + i2), and the distance data and the reflected light amount data are obtained by the calculation units 18 and 17, respectively. These data are input to the CPU 10 via the I / O unit 19, where the distance data is corrected by the light amount data as described later.

Reference numeral 9 denotes a motor controller driver for controlling a motor for moving the XY table 2 in the XY direction. The motor controller driver 9 is controlled by a CPU 10 including a microprocessor or the like. The height of the nozzle 3 is also adjusted by the motor controller driver 9 controlled by the CPU 10.

The height sensor 6 is configured such that the circuit board 1 is
Since it moves in the direction, it relatively moves with respect to the circuit board 1, so that the circuit board 1 is scanned in a line.
Therefore, the light quantity data and the distance data obtained from the height sensor 6 are sequentially stored in the distance data map storage unit 20a of the memory 20.
Is stored in The memory is provided with a drawing data storage unit 20b, and the drawing data stored therein is taken into the CPU 10, where the movement data of the XY table 2 and the control data of the motor 5 for moving the ink pen 4 up and down are stored. And inputs these data to the motor controller driver 9 to discharge the paste onto the circuit board 1 via the nozzle 3 while drawing the ink pen 4 while adjusting the ink pen 4 to a predetermined height.

Next, a correction method according to an embodiment of the present invention will be described with reference to such a drawing apparatus.

First, as shown in steps S1 and S2 of FIG. 3, the power is turned on or reset to initialize each unit. Subsequently, in step S3, the input of the amount of reflected light of the base portion of the circuit board 1 is displayed on an indicator attached to the main body of the drawing apparatus, and in step S4, the circuit board 1 is manually operated or the height sensor 6 Move down and apply the laser spot to the circuit board.
By pressing the setting key in step, the amount of reflected light is measured. Subsequently, in steps S6 to S8, the reflected light amount input of the conductor of the circuit pattern to be drawn is displayed on the indicator, and the reflected light amount from the conductor is measured by pressing the setting key in the same manner. Each measured value of the reflected light amount is stored in the memory 20.

Note that the measurement of the amount of reflected light from the conductor is performed when the circuit pattern is already drawn, when the power is turned on or during standby other than during drawing, and when drawing is not yet performed,
It should be performed using a sample such as a sample of an appropriate conductor prepared in advance.

Subsequently, the XY table 2 is driven under the control of the CPU 10,
Obtain distance data and reflected light amount data. For example,
The distance data and the reflected light amount data when the conductor 30 and the insulating glass 31 are drawn on the ceramic circuit board 32 as shown in FIG. 4 (A) are shown in FIGS. 4 (B) and 4 (C). Have been.

In FIG. 4 (B), the data indicated by the solid line A is the measured distance data, and it can be understood that a protruding error 35 occurs at the boundary between the circuit board and the circuit pattern. As shown in FIG. 4 (C), this error is determined as a boundary when the amount of reflected light passes a predetermined threshold value H. Threshold H
The intersection can be corrected by removing the data by a predetermined distance along the moving direction centering on the intersection point with the distance data, and replacing the height data of the removed portions with the distance data separated by a predetermined distance.

However, in practice, the amount of reflected light varies depending on the material of the conductor, changes over time, and the like. As shown in FIG. 5, when the material of the conductor is made of gold (30a), silver (30b), or The value of the amount of reflected light changes between a case where it is made of palladium and is new (30c) and a case where time has elapsed (30d). Therefore, when the threshold value H is predetermined, the fourth
As shown in the lower diagram, the data after the correction processing cannot obtain the height data corresponding to the actual shape. Therefore, in the present invention, the threshold value H is adjusted based on the values of the amounts of reflected light of the conductor and the circuit board substrate measured in steps S5 and S8 described above. Specifically, for example, a value approximately halfway between the values of the reflected light amounts of the conductor and the circuit board substrate is set to a new threshold (H1 to H3).
And the above-described distance data is corrected. As a result, height data corresponding to the actual shape is obtained as shown in the lowermost part of FIG.

In addition, as shown in FIG. 4A, when the insulating glass 31 is drawn on the circuit board 32 and then the conductor 30 is drawn, the insulating paste has almost all glass components and the laser light is , The measured height data has a value smaller than the actual value because an error E occurs due to the insulating glass.

This correction is performed as follows. As shown in FIG. 4 (A), laser light is applied to the boundary of the insulating glass.
When the temperature of 33 is reached, the glass is thicker than the other conductors, and the glass boundary has an angle at which the reflected light is less likely to enter the incident light. As shown by, it decreases like a spike. Therefore, as shown in step T1 of FIG. 6, it is checked whether or not a spike-shaped light amount decrease has occurred in the reflected light amount, and if so, it is checked in step T2 whether there is a difference between the height data on both sides. If there is, the higher one is recognized as glass (step T3), the distance data is increased by a predetermined correction amount, and the distance data by glass is corrected. Further, the error E 'of the original circuit board is corrected.

In this manner, data obtained by correcting the difference in the amount of reflected light from the conductor and the error in the distance data between the circuit board and the insulating glass is shown by a dotted line B in FIG. 4B, and the data corresponding to the actual shape is shown in FIG. It can be understood that it can be obtained.

In addition, since some glass is also colored and a difference occurs in the amount of reflected light similarly to the conductor, steps S9 to S9 in FIG.
As shown in S11, the value of the reflected light amount of the glass portion may be stored, and when the glass portion is recognized, the threshold value H may be corrected correspondingly.

[Effects of the Invention] As described above, in the present invention, the predetermined threshold value is set based on the sample reflection light amounts of the circuit board substrate and the drawing pattern. , A threshold value corresponding to the change can be set, and the distance data can be accurately corrected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a direct drawing apparatus to which the method of the present invention is applied, FIG. 2 is a perspective view showing the appearance of a circuit pattern and a height sensor, and FIG. 4 (A) to 4 (C) are explanatory diagrams illustrating a state of distance data acquisition, FIG. 5 is an explanatory diagram illustrating correction of distance data, and FIG. 6 is a circuit diagram of a circuit pattern. 5 is a flowchart showing a flow of control for identifying a material. 1 ... circuit board 2 ... XY table 3 ... nozzle 6 ... height sensor 10 ... CPU 20 ... memory 30 ... conductor 31 ... insulating glass 32 ... ceramic substrate

Claims (4)

(57) [Claims] A thick film circuit direct drawing method for drawing a thick film circuit pattern on a circuit board by obtaining vertical distance data from a reflecting surface using a height sensor for receiving reflected light from the circuit board. A predetermined threshold value is set from the sample reflected light amount of each of the substrate base and the drawing pattern, the reflected light amount from the circuit board is measured, and when the reflected light amount passes the threshold value, it is determined that the boundary is present. A thick film circuit direct drawing method, wherein the distance data at the boundary is corrected by replacing it with distance data at a predetermined distance from the boundary, and drawing is performed according to the corrected distance data. 2. The method according to claim 1, wherein the sample reflected light amount is measured before drawing. 3. The method according to claim 1, wherein the threshold value is set to a value approximately equal to the intermediate value between the sample reflected light amounts of the circuit board substrate and the drawing pattern. . 4. The method according to claim 1, wherein the material of the pattern is determined to be a glass material when a decrease in the amount of reflected light in the form of a spike is measured during drawing, and the distance data obtained based on the amount of reflected light at this time is corrected. The method for directly drawing a thick film circuit according to any one of claims 1 to 3, wherein: