JPH02303085A - Trimming of conductor pattern - Google Patents

Abstract

PURPOSE:To obtain an integrated circuit having high reliability concerning a circuit function without damaging the substrate surface by a method wherein, when material of a part of a conductor pattern on a substrate is eliminated, spark discharge energy accompanying discharging current flowing only between the conductor pattern and a discharging electrode is used. CONSTITUTION:A conductor pattern 2 having an object part position 5 to be subjected to trimming is formed on an insulating substrate 1. When the object part position 5 is subjected to trimming, a discharging electrode 4 is arranged above the object part position 5 by interposing a suitable discharging gap (g), and a terminal electrode 3 is brought into contact with a suitable position of the pattern 2. In this state, a high voltage is applied between the terminal electrode 3 and the discharging electrode 4, thereby concentrating electric field in the gap (g) formed in the object part position 5 of the pattern 2. By the effect of spark discharge generated in the gap (g), material of the trimming object part position 5 is evaporated without fusing, so that a desired pattern is formed without damaging the substrate 1.

Description

[Detailed Description of the Invention] [Field of Application in Industry A] The present invention is a method for cutting conductor patterns formed on various insulating substrates at predetermined locations, such as ceramic substrates used as circuit boards for various electronic circuits. The present invention relates to a trimming method commonly used to remove a substrate or a part thereof, and particularly relates to an improvement to prevent scratches on the surface of a substrate.

[Prior Art] For example, in a hybrid integrated circuit (HIC), etc., a ceramic substrate is selected as a circuit substrate on which various electronic ports and circuit elements are constructed and supported. Various conductor patterns are patterned to form a wiring line, one electrode of a capacitor, or a terminal line for circuit testing.

On the other hand, after the ladder conductor patterns formed on the insulating substrate in this way are formed, depending on the required circuit function, the necessary wiring system is left and unnecessary wiring is removed, or the circuit function is changed. After the test, a trimming process is performed to remove unnecessary terminals or to adjust the capacitance value of the capacitor by reducing the width or length of the planar conductor pattern. It is often done.

However, the conventional method for trimming conductor patterns used in such cases is to physically trim alumina particles with a diameter of several tens of microns by blowing them out from a nozzle together with compressed air and hitting the target area of the conductor pattern. The abrasive method, which scrapes the conductive material, and the laser
The beam irradiates the conductor material instantly and locally,
Typical methods include a laser method that evaporates, and a machine trimming method that uses a drill or sharp blade.

[Problems to be Solved by the Invention] However, all of the above-described conventional methods have a major drawback in that they inevitably damage the substrate surface when trimming the conductor pattern.

If the board is damaged, its strength will naturally decrease, and above all,
The resulting unevenness on the substrate surface becomes a problem.

In reality, in this type of integrated circuit, the final process is almost never complete after the trimming of the conductor pattern, and after that, the printing process of various materials is involved, but at that time, the substrate may be scratched as described above. If so, the printability will be extremely deteriorated, making it difficult to construct various circuit elements thereafter. In fact, for this reason, printing has been carried out to avoid the upper part of the trimming part.

In recent years, there has been a strong demand for smaller circuit boards and higher integration density, but under these circumstances, scratches on the board surface that occur at the conductor trimming part, as described above, have a significant impact on subsequent processes. On the contrary, this becomes a major obstacle to the promotion of higher density.

In view of these circumstances, the present invention provides a method for trimming a conductor pattern on an insulating substrate, in which only the forming material of the conductor pattern can be effectively and precisely removed without damaging the substrate. That is.

1. Means for Solving the Problem] In order to achieve the above object, in the present invention, a discharge electrode is attached to a trimming portion of a conductor pattern formed on an insulating substrate where at least a portion of the material is to be removed. A trimming method is disclosed in which a high voltage is applied to the discharge electrode and the conductor pattern, and the conductor material at the trimming target area is melted or evaporated away by the spark discharge energy generated between them.

[Function] According to the present invention, material removal of a part of the conductor pattern on the insulating substrate is performed by spark discharge energy (in principle, thermal energy) accompanied by a discharge current flowing only between the conductor pattern and the discharge electrode. This fact has been confirmed by the inventor of the present invention.

Compared to existing trimming methods, this method can be said to be the only method that does not damage the substrate.

Furthermore, the conductor pattern can be removed to a roughly similar shape depending on the shape of the tip of the discharge electrode.

[Embodiment] FIG. 1 shows an example of an apparatus configuration to which the trimming method of the present invention is applied as an embodiment.

A conductive pattern 2 having a target portion 5 to be trimmed by this method is formed on an insulating substrate 1 such as a ceramic substrate.

Trimming of the portion 5, particularly cutting of the conductive pattern 2 at the portion 5 in this case, is performed as follows.

Above the trimming target area 5 of the conductor pattern 2,
The discharge electrode 4 is placed facing the electrode with a suitable discharge gap g, while the terminal electrode 3 is placed somewhere on the conductor pattern 2.
contact.

In this state, when a high voltage is applied from a power supply (not shown) between the terminal electrode 3 and the discharge electrode 4, a discharge is formed between the tip of the discharge electrode 4 and the trimming target portion 5 of the conductor pattern 2 below. The electric field is concentrated in the gap g.

Therefore, if the voltage value and the discharge gap distance are appropriately adjusted (this adjustment is extremely easy), a spark discharge will occur in the discharge gap g, and the converted thermal energy will cause the conductor pattern 2 to The material of the region 5 to be trimmed is melted or evaporated and removed as desired.

FIG. 2 shows the state in which the conductor pattern 2 is completely cut at the relevant part 5, but according to the inventor's experiments, even when an excessive discharge is performed, It was confirmed that the surface of the substrate 1 was not damaged. Naturally, spark discharge always occurs only between the discharge electrode 4 and the portion of the conductor pattern closest to it, and as a result, the conductor pattern 2 may be removed to a greater extent than expected. No scratches were observed on the substrate 1.

In the illustrated case, the tip shape of the discharge electrode 4 is a simple rectangle, but in order to enhance the electric field concentration effect, it may be made into a more pointed shape.
The planar shape of the removed portion of the conductive pattern removed by discharge also has a similar shape, so this can be actively utilized. For example, if a discharge electrode 4 whose tip planar shape is a crescent shape is used, The deletion trace of the conductor pattern 2 also has such a crescent shape, or at least a shape close to this.

Therefore, for example, if the discharge electrode 4 has a shape having a plurality of bottle points, a process such as drilling a plurality of round holes equal to the number of protrusions (bottles) in the conductor pattern 2 at once may be performed. is also possible. Taking these things into consideration, the term "trimming" in the present invention can be understood as a comprehensive term that includes such processing or material removal for pattern formation.

Furthermore, when it is necessary to remove the conductor patterns 2 over a wide area, the discharge may be repeated while scanning the substrate 1 and the discharge electrode 4 relatively in a two-dimensional direction.

Of course, this method can be used not only to simply cut a conductor line midway, but also to remove a part of a planar conductor pattern, for example, to create a capacitor whose planar electrode is used as a terminal electrode. It can also be used to adjust the capacitance value, and it is also advantageous for the purpose of simply reducing the thickness of the conductor pattern, rather than removing the conductor material over its entire thickness until the substrate surface is exposed. It can be passed.

Note that the high voltage generating power source for discharging may be either direct current or alternating current in principle.

[Effects] According to the present invention, even if a conductor pattern on an insulating substrate is trimmed, the surface of the substrate is not damaged, so it is possible not only to prevent a decrease in physical strength, but also to prevent a decrease in physical strength.
When printing the required materials in the subsequent steps,
There is no longer any need to avoid the area above the trimming section.

As a result, it has become possible to greatly contribute to increasing the integration density of circuit boards, and it has also become possible to guarantee high reliability regarding circuit functions.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an application example of the trimming method of the present invention;
The figure is an explanatory diagram showing the conductor pattern removed by the first illustrated method. In the figure, 1 is an insulating substrate, 2 is a conductor pattern, 3 is a terminal electrode, 4 is a discharge electrode, and g is a discharge gap.

Claims (1)

[Claims] A method for trimming a conductor pattern formed on an insulating substrate, comprising: placing a discharge electrode facing the trimming target portion of the conductor pattern, and applying a high voltage to the discharge electrode and the conductor pattern. A method for trimming a conductor pattern, comprising: generating a spark discharge between them, and using the spark discharge energy to remove the conductor material at the trimming target portion.