JPS61182894A - Laser-scribe method on alumina substrate - Google Patents

Abstract

PURPOSE:To prevent cracking of the alumina substrate and improve quality by providing an auxiliary layer in the laser subscribe area on the alumina substrate, and irradiating the laser beam along the auxiliary layer to form scribes. CONSTITUTION:Conductive paste or glass paste is printed in the scribe area 4 on the alumina substrate 1, and sintered to form auxiliary layers 5. Then, laser beam is irradiated on the auxiliary layer 5 to draw scribe lines 4 in the scribe area on the alumina substrate 1. In this process, the auxiliary layer 5 absorbs the laser beam to lower the laser power density. Thus, scribe lines 4 with a minute width are drawn in the scribe area on the alumina substrate and the substrate is free of cracking.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a laser scribing method for an alumina substrate, and particularly to a laser scribing method for an alumina substrate suitable for forming a scribe line of extremely small width on the alumina substrate.

[Background of the invention]

Conventionally, as shown in FIG. 3, in a thick film wiring board composed of a large number of thick film hybrid integrated circuits, after screen printing is performed using a thick film paste on an alumina substrate 1, the temperature is around 150°C. Dry at temperature SOO~950℃
The conductor 2 and the resistor 3 are formed by firing in a high temperature air atmosphere. Next, generally, after trimming the resistor 3 to a predetermined resistance value, the alumina substrate l is trimmed.
In order to divide a large number of thick film hybrid integrated circuits 1a by irradiating a laser beam onto the position shown by the dotted line on the opposite side of the mother turn forming surface as shown in FIGS. 3 and 4, the alumina substrate IK is
A scribe line 4 is formed.

In the scribing using the laser beam, the material on the scribe line 4 is evaporated and removed by the energy of the laser beam. Therefore, in consideration of processing efficiency, it is necessary to evaporate the alumina substrate 1 efficiently without melting a large amount. It is said that the powder density when irradiated with laser light must be 1 d' W/d or more.

Laser beams for the alumina substrate 1 that are suitable for these conditions include the Gurus type CO, gas laser, and YAG laser, which have a high peak output, but considering the heat absorption of the laser beam into the alumina substrate 1, 1.06μm co,
It is common to use y slaves.

However, since the conductor 2 and resistor 3 are formed near the scribe line 4 as shown in FIG. When the distance is 50 to 80", it is difficult because the cross-sectional shape of the scribe line is inverted triangular and a large amount of molten material is eluted. Therefore, a YAG laser is used, but the wavelength is 1.0.
The absorption characteristic of the alumina substrate 1 for a YAG laser of 6 μm is as small as 10 to 20%, and when the thickness of the alumina substrate 1 becomes 0.8 m or more and the warpage becomes 0.1 m or more, a scribe line 4 is formed. It can be difficult to do so. Therefore, it is possible to increase the average power of the laser beam, but if the average power of the laser beam is increased, there is a problem that cracks occur in the alumina substrate 1 and the quality of the alumina substrate 1 after scribing deteriorates.

A conventional scribing method using a laser beam is introduced, for example, in "Laser processing of ceramics" in "Mechanical Engineering", Vol. 30, No. 2, pages 1 to 7. However, this document does not recognize the point of improving the absorption efficiency of laser light.

[Purpose of the invention]

In view of the above-mentioned state of the prior art, the present invention makes it possible to improve the quality by preventing cracks from occurring on the alumina substrate when forming extremely narrow scribe lines on the alumina substrate (using laser light). An object of the present invention is to provide a method for laser scribing an alumina substrate.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention forms an auxiliary layer of thick film paste or other coloring agent on the laser scribed portion of an alumina substrate, and forms a scribe by irradiating the auxiliary layer with laser light. It is characterized by:

[Embodiments of the invention]

FIG. 1 showing an embodiment of the present invention will be described below. As shown in FIG. 1, an auxiliary layer 5 is formed using a conductor paste, a glass paste, a resistor (-stack, etc.) on the Levstar live portion 4 of the alumina substrate 1 using a printing and firing method.

Next, when the auxiliary layer 5 is irradiated with a laser beam, a scribe line 4 is formed in the laser scribe portion of the υ alumina substrate 1 by the laser beam. At this time, the auxiliary layer 5 absorbs the laser beam and reduces the laser density.
It is possible to prevent cracks from occurring in the alumina substrate 1, and to form a scribe line with an extremely small width in the laser scribe portion of the alumina substrate 1. It is sufficient if the thickness of the auxiliary layer 5 is 1 μm or more, but if it is too thick, only the auxiliary layer 5 will be evaporated by the laser beam.
In some cases, it may not be possible to remove the scribe line 4 on the alumina substrate 1. Further, the auxiliary layer 5 is not limited to the above-mentioned thick film paste, and the alumina substrate 1
Any colorant capable of absorbing laser light can be used as long as it does not degrade the properties of the thick film hybrid integrated circuit using the colorant. Next, FIG. 2 shows another embodiment of the present invention, in which the auxiliary layer 5 is formed intermittently on the line forming the scribe M4. According to experiments by the inventor of the present invention, when the length a and the spacing of the auxiliary layer 5 were set to 3w or less, the same effect as the embodiment shown in FIG. 1 was obtained.

〔Effect of the invention〕

As described above, the present invention forms an auxiliary layer that absorbs laser light on the laser scribe portion of an alumina substrate, and irradiates this auxiliary layer with laser light to form a fine width scribe on the alumina substrate. Therefore, it is possible to improve the absorption characteristics of laser light to the alumina substrate, thereby forming a scribe with a fine width, and also to prevent the generation of cracks in the alumina substrate, thereby improving the quality of the alumina substrate.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an alumina substrate having an auxiliary layer showing one embodiment of the present invention, FIG. 2 is a plan view of an alumina substrate having an auxiliary layer showing another embodiment of the present invention, and FIG. FIG. 4 is a plan view showing a conventional thick film wiring board having a large number of thick film hybrid circuits, and FIG. 4 is a plan view of an alumina board having scribe lines. 1...Alumina substrate, 2...Conductor, 3...Resistor, 4...Scribe wire, 5...Auxiliary layer agent Patent attorney Tadashi Akimoto Figure 1

Claims (1)

[Claims] 1. An auxiliary layer that absorbs laser light is formed in the laser scribe portion of the alumina substrate, and the auxiliary layer is irradiated with laser light to form a fine width scribe on the alumina substrate. Laser scribing method for alumina substrates. 2. The method of laser scribing an alumina substrate according to claim 1, wherein the auxiliary layer is formed of a paste capable of absorbing laser light. 3. The method of laser scribing an alumina substrate according to claim 1, wherein the auxiliary layer is formed of a coloring agent capable of absorbing laser light.