JPH07120856B2 - Method for manufacturing ceramic laminated substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to a method for manufacturing a ceramic substrate, wherein the polishing residue remaining in the pores of the main body is surely removed before forming a conductor pattern on the surface of the ceramic laminated substrate. Between a polishing step of mechanically polishing the surface of the main body of the ceramic laminated substrate on which the via exposed to the is formed, and a conductor pattern forming step of forming a conductor pattern on the surface of the main body where the via after exposure is exposed, In the method for manufacturing a ceramic laminated substrate, which comprises a cleaning step of cleaning the polishing residue attached to the main body at the time of polishing with a solvent, the polishing residue in a vacuum or an inert atmosphere between the cleaning step and the conductor pattern forming step. The heat treatment step of heating the main body at a temperature higher than the boiling point of the alcohol contained in was added.

[Industrial application field]

 The present invention relates to a method for manufacturing a ceramic laminated substrate.

[Conventional technology]

Generally, a ceramic laminated substrate is manufactured through a step of forming a main body of a ceramic substrate, that is, a state in which no conductor pattern is formed, and a conductor pattern forming step of forming a conductor pattern on the surface of the main body by sputtering and etching. .

In the main body formation process, the vias are formed in the green sheet, the conductors are embedded in the vias, then the inner layer pattern is formed by printing, and the inner layer green sheet of the required number of layers with the inner layer pattern is formed By sandwiching between the polishing layer green sheets and applying pressure, and further applying pressure and heating to sinter, a main body in which the via filled with the conductor is exposed from the inside to the surface is formed.

Then, in the conductor pattern forming step, the conductor pattern is formed on the polished surface of the main body.

For example, as shown in FIG. 3A, the flatness of the surface of the main body 1 after the sintering process is low. Since it is necessary to form the surface of the main body 1 in an accurate plane as shown in FIG. 3 (e) in the conductor pattern forming step, a polishing step is provided between the firing step and the conductor pattern forming step.

In this polishing step, as shown in FIG. 3 (b), a lapping machine 5 or the like is used, and the polishing agent 6 is supplied between the rotating surface plate 12 and the main body 1 supported by the vacuum chuck 13 while the main body 1 is being supplied. Is pressed against the surface plate 12, and both surfaces of the main body 1 are polished so that the waviness of the surface thereof is about 10 μm or less as shown in FIG. 3 (d).

As the abrasive 6, for example, a slurry abrasive 6 containing abrasive grains such as diamond having a diameter of about 1 μm and higher alcohol as lubricating oil is used. The polishing residue 7 made of scraps and the like remains on the surface of the main body 1 and inside the pores 4 opened on the surface of the conductor 3 in the via 2, for example, as shown in FIG. Since this polishing residue 7 contains the above-mentioned higher alcohol, when the process proceeds to the conductor pattern forming process as it is, it is brought to the conductor pattern forming process without being volatilized into the atmosphere.

In the conductor pattern forming step, the conductor thin film formed on the entire surface of the main body 1 is etched by sputtering to form the conductor pattern 11 on the surface of the main body 1 as shown in FIG. 3 (e). The polishing residue 7 brought into the conductor pattern forming step is heated in the conductor pattern forming step, for example, in the curing step, decomposes to generate gas, oxidizes the conductor pattern 11, corrodes the conductor pattern 11, The conductor pattern 11 may be peeled off from the main body 1. In the conductor pattern forming step, the metal thin film may be formed by a method such as vapor deposition or CVD other than the above-mentioned sputtering. However, even if any of these methods is used, the main body 1 is exposed to a constant high temperature. As a result, the conductor pattern 11 is damaged in the same manner as above.

Therefore, generally, as shown in FIG. 3C, a cleaning step for cleaning the main body 1 is provided between the polishing step and the conductor pattern forming step to remove the polishing residue 7 and then the conductor pattern forming step. Is configured to transition to.

In this cleaning step, an ultrasonic cleaning method is employed in which the main body 1 is immersed in an organic solvent 8 that volatilizes at about room temperature, such as chlorothene, freon, and alcohol, and the ultrasonic oscillator 9 vibrates the organic solvent. Evaporates into the atmosphere during the transition from the cleaning step to the conductor pattern forming step.

[Problems to be Solved by the Invention]

However, for example, as shown in FIG. 3D, if the pores 4 are in communication with the surface of the main body 1 at the end of the polishing step, the polishing residue 7 will penetrate into the pores 4 during the polishing step, and the polishing step After the end of, the polishing residue 7 is left in the pores 4. Moreover, the polishing residue 7 remaining in the pores 4 cannot often be completely removed by the conventional cleaning process. Then, the polishing residue 7 remaining in the pores 4 is heated in the conductor pattern forming step, decomposes and is ejected from the pores 4, and the conductor pattern 11 is oxidized, corroded, or peeled from the surface of the main body 1. Then, the main body 1 and the conductor pattern
There is a problem that the reliability of the conductor connection with 11 is impaired.

And, this problem is regarded as a very important problem particularly in a ceramic laminated substrate which can exhibit characteristics such as high density, low thermal expansion coefficient, low dielectric constant, etc., in response to demands for higher processing speed, smaller size and the like. .

The present invention has been made in consideration of the above circumstances,
An object of the present invention is to provide a method for manufacturing a ceramic laminated substrate in which the polishing residue 7 remaining in the pores 4 of the body 1 can be reliably removed before the conductor pattern is formed on the body surface of the ceramic substrate.

[Means for Solving the Problems]

For example, as shown in FIG. 1, the present invention includes a polishing step of mechanically polishing the surface of the main body 1 of the ceramic laminated substrate in which the via 2 exposed from the inside of the main body 1 is formed, and the via 2 after the polishing. During the conductor pattern forming step of forming the conductor pattern 11 on the surface of the body where the body is exposed, the body 1 is polished.
Assuming a method for manufacturing a ceramic laminated substrate, which is provided with a cleaning step for cleaning the polishing residue 7 attached to
In order to achieve the above object, a heat treatment for heating the main body 1 between the cleaning step and the conductor pattern forming step at a temperature higher than the boiling point of the alcohol contained in the polishing residue 7 in a vacuum or an inert atmosphere. A process is provided.

[Action]

In the present invention, most of the polishing residue 7 is washed off and removed from the main body 1 in the cleaning step, but alcohol mainly contained in the polishing agent remains in the pores 4 of the conductor 3 as the polishing residue 7. There is. Then, the polishing residue 7 containing alcohol remaining in the pores 4 is heated to a temperature higher than its boiling point in the heat treatment step prior to the conductor pattern forming step, and the alcohol content is ejected from the pores 4 and removed. Since this heat treatment is performed in a vacuum or an inert atmosphere 10, there is almost no risk that the conductor of the main body 1 will be oxidized by the polishing residue 7 decomposed by the heat treatment.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In this method for manufacturing a ceramic laminated substrate, as shown in FIG. 1 (a), the main body at the end of the firing step in the main body forming step has a low surface flatness and has pores 4 in the conductor 3 in the via 2. Are formed.

Therefore, after the firing step is completed and before the conductor pattern forming step of forming the conductor pattern 11 on the surface of the main body 1 is performed as shown in FIG. 1 (f), as shown in FIG. A polishing step of polishing 1 is provided.

In this polishing step, as shown in FIG. 1 (b), mechanical polishing is performed by, for example, a lapping machine 5. This lapping machine 5
Is a diamond having an average particle size of about 1 μm between the surface plate 12 and the main body 1 while pressing the main body 1 supported by the vacuum chuck 13 against the upper surface of the surface plate 12 that horizontally rotates at a predetermined rotation speed with a predetermined pressure. A slurry abrasive 6 containing abrasive grains and a higher alcohol such as ethylene glycol or glycerin as lubricating oil is supplied to polish the main body 1 with diamond abrasive grains.

The undulations on the surface of the main body 1 after the polishing process are, for example,
The surface is finished to have a flatness of about 10 μm or less, and polishing residues 7 made of polishing dust and a polishing agent are attached to the surface and the pores 4 opening therein. Since this polishing residue 7 contains the above-mentioned higher alcohol, it decomposes when heated in the conductor pattern forming step to oxidize the conductor pattern 11,
Since it causes corrosion, peeling, etc., the main body 1 is washed before proceeding to the conductor pattern forming step.

In the cleaning step for cleaning the main body 1, as shown in FIG. 1 (c), the main body 1 is immersed in an organic solvent 8 such as chlorothene, freon, alcohol, etc. An ultrasonic cleaning method of vibrating is adopted.

In this cleaning step, the polishing residue 7 adhering to the surface of the conductor 3 forming the via 2 and the polishing residue 7 in the pores 4 having a large opening in the surface of the main body 1 are completely removed. However, as shown in FIG. 1 (d), the polishing residue 7 in the pore 4 having a small opening area to the surface of the conductor 3 is often left uncleaned.

Therefore, in order to remove the polishing residue 7 remaining in the pores 4, a heat treatment step is provided.

That is, as shown in FIG. 1 (e), the main body 1 after the cleaning process is placed in a vacuum or an inert gas 10 such as nitrogen,
Higher than boiling point of higher alcohol contained in polishing residue 7 with heater 14 (eg, 197.5 ° C for ethylene glycol, 290 ° C for glycerin) (eg, 350 ° C or higher)
The higher alcohol is decomposed by heating to 1, and is ejected from the pore 4 to be removed.

In this heat treatment step, as shown in FIG. 2, for example, the heating chamber is replaced with nitrogen gas at room temperature for a predetermined purge period a, and the atmosphere temperature is increased by a large thermal strain on the main body 1 during a temperature raising period b following the oxygen purge. ,crack,
The temperature is raised to a predetermined temperature (here, 350 ° C.) with a temperature rising gradient such that delamination does not occur, the atmosphere temperature is maintained at the predetermined temperature during the heat retention period c, and then the ambient temperature is maintained for the cooling period d. The procedure is adopted in which the main body 1 is cooled to room temperature by nitrogen cooling or indirect water cooling with a temperature decreasing gradient that does not cause large heat distortion, cracks, delamination and the like.

Then, after this heat treatment step is completed, FIG.
As shown in FIG. 3, in the conductor pattern forming step, first, a conductor pattern 11 is formed by forming a thin conductor layer on the entire surface of the main body 1 by sputtering and etching the conductor layer. Since the polishing residue 7 is completely removed from the main body 1 by the cleaning process and the heat treatment process,
In this conductor pattern forming step, there is no possibility that the polishing residue 7 is decomposed and the conductor pattern 11 is oxidized, corroded, or peeled from the main body 1, and the main body 1 and the conductor pattern 11 are not separated.
Connection reliability is significantly increased.

In one embodiment described above, the heat treatment step is performed with an inert gas.
The main body 1 is configured to be heated in 10; however, instead of this, the main body 1 is placed in a vacuum with a vacuum degree of, for example, 10 ^-1 atmosphere or less.
May be heated. Further, the pressure of the inert gas in the heat treatment step does not have to be normal pressure, and may be maintained at a pressure lower than this.

〔The invention's effect〕

As described above, in the present invention, between the cleaning step and the conductor pattern forming step, a heat treatment step of heating the main body at a temperature equal to or higher than the boiling point of alcohol contained in the polishing residue in an inert atmosphere is provided, and the heat treatment is performed. Since the polishing residue remaining in the pores of the main body is thermally decomposed and ejected from the pores and removed in the process, the polishing residue remaining in the pores of the main body can be reliably removed before the conductor pattern is formed. Further, as a result, it is possible to prevent the conductive pattern from being oxidized, corroded or peeled off due to polishing residue in the conductive pattern forming step, so that the reliability of the conductor connection between the main body and the conductive pattern can be remarkably enhanced.

[Brief description of drawings]

FIG. 1 is an explanatory view sequentially showing the procedure of a method for manufacturing a ceramic laminated substrate according to an embodiment of the present invention, FIG. 2 is a temperature control diagram of the heat treatment step, and FIG. 3 is a conventional ceramic laminated substrate. It is explanatory drawing which shows the procedure of a manufacturing method in order. In the figure, 1 ... Main body, 7 ... Polishing residue, 10 ... Inert gas, 11 ... Conductor pattern.

Claims (1)

[Claims] 1. A polishing step of mechanically polishing the surface of the main body of the ceramic laminated substrate having vias exposed from the inside of the main body, and a conductor pattern is formed on the surface of the main body where the vias after polishing are exposed. In the method for manufacturing a ceramic laminated substrate, which is provided with a cleaning step of cleaning the polishing residue adhered to the main body during polishing with a solvent between the conductive pattern forming step, a vacuum is provided between the cleaning step and the conductive pattern forming step. Alternatively, there is provided a heat treatment step of heating the main body at a temperature higher than the boiling point of the alcohol contained in the polishing residue in an inert atmosphere, the method for producing a ceramic laminated substrate.