JP2010103168A - Method for producing ceramic substrate, and method for producing substrate for power-module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing ceramic substrate that can acquire full bonding strength, when bonding a ceramic substrate containing Si and a metal member to each other, while improving the bonding reliability during thermal cycling, and to provide a method for manufacturing a power-module substrate. <P>SOLUTION: The method for manufacturing a ceramic substrate includes a step S10 for sintering a ceramic base-material containing Si; a surface treatment step S20 for applying dry etching to the surface of the ceramic base-material by using gas including fluoride ions; and a step S30, in which a concentration of a silicon oxide and that of a silicon composite oxide on the surface of the ceramic base-material are respectively set to ≤2.7 atom% by surface measurements that use an electron probe microanalyzer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a ceramic substrate containing Si and a method for producing a power module substrate using the ceramic substrate.

For example, a power module on which an electronic component such as a semiconductor chip is mounted generally includes a ceramic substrate made of AlN (aluminum nitride), Al ₂ O ₃ (alumina), Si ₃ N ₄ (silicon nitride), SiC (silicon carbide), and the like. A power module substrate having a circuit layer of a metal member arranged on the upper surface of the ceramic substrate and a metal layer of a metal member arranged on the lower surface of the ceramic substrate, and on the circuit layer of the power module substrate In addition, a semiconductor chip as a heating element is disposed, and a cooling heat sink is disposed on the lower surface of the metal layer (see Patent Document 1).

The power module is configured to dissipate the heat generated in the semiconductor chip to the cooling water in the heat sink via the metal layer.
Here, the thickness of the ceramic substrate can be reduced by using Si ₃ N ₄ having excellent mechanical properties such as higher bending strength than AlN as the ceramic substrate.
Japanese Patent Laid-Open No. 2002-9212

However, the following problems remain in the conventional power module substrate.
For example, when these are joined using a ceramic substrate made of Si ₃ N ₄ containing Si and a metal member made of Al (aluminum), poor bonding occurs between the ceramic substrate and the metal member. There is.

That is, SiO ₂ (silicon oxide) or silicon composite oxide generated when the ceramic substrate is sintered is present on the surface portion to which the ceramic substrate is bonded. SiO gas resulting from the composite oxide is generated, and a sufficient bonding area between the ceramic substrate and the metal member cannot be secured. Due to such poor bonding, the ceramic substrate and the metal member are easily peeled off during the thermal cycle.

  The present invention has been made in view of the above-mentioned problems. When a ceramic substrate containing Si and a metal member are bonded, sufficient bonding strength is obtained, and bonding reliability during thermal cycling is improved. An object of the present invention is to provide a method for manufacturing a ceramic substrate and a method for manufacturing a power module substrate.

In order to achieve the above object, the present invention proposes the following means.
That is, the method for manufacturing a ceramic substrate according to the present invention includes a step of sintering a ceramic base material containing Si, and a surface treatment step of performing dry etching on the surface of the ceramic base material using a gas containing fluoride ions. And a step of setting the concentration of silicon oxide and silicon composite oxide on the surface of the ceramic base material to 2.7 Atom% or less by surface measurement using an electron probe microanalyzer.
The method for manufacturing a power module substrate according to the present invention includes a step of sintering a ceramic base material containing Si, and a surface on which dry etching is performed using a gas containing fluoride ions on the surface of the ceramic base material. A ceramic substrate manufactured by a processing step and a step of setting the concentration of silicon oxide and silicon composite oxide on the surface of the ceramic base material to 2.7 Atom% or less by surface measurement using an electron probe microanalyzer And a metal member.

According to the method for manufacturing a ceramic substrate and the method for manufacturing a power module substrate according to the present invention, after sintering a ceramic base material containing Si, ceramics in a state where silicon oxide and a silicon composite oxide are adhered to the surface Since the base material is dry-etched using a gas containing fluoride ions, the concentration of silicon oxide and silicon composite oxide on the surface of the ceramic base material is 2 by surface measurement using an electron probe microanalyzer. .7 Atom% or less. That is, in the surface treatment process, silicon oxide and silicon composite oxide on the surface of the ceramic base material react with fluoride ions to be removed from the surface as highly volatile SiF ₄ (silicon tetrafluoride) gas. The concentration of silicon oxide and silicon complex oxide on the surface is reliably reduced to 2.7 Atom% or less in the surface measurement.

  Accordingly, since the generation of SiO (silicon monoxide) gas due to the silicon oxide and the composite oxide of silicon is suppressed when the ceramic substrate thus manufactured and the metal member are joined, the ceramic substrate A sufficient bonding area between the metal member and the metal member is ensured, and the ceramic substrate and the metal member are prevented from being peeled off during the thermal cycle, thereby improving the bonding reliability.

Further, fluoride ions contained in the dry etching gas become SiF ₄ gas due to the above-described reaction, and therefore do not remain as fluoride on the surface of the ceramic base material. Further, since dry etching has less wraparound of the reaction as compared with, for example, wet etching of a ceramic base material, it is possible to suppress fluoride from remaining in response to the sintering aid more than necessary. Therefore, when the ceramic substrate and the metal member are bonded, it is possible to prevent a bonding failure from being caused due to the fluoride, and the bonding reliability between the ceramic substrate and the metal member is reliably increased.

  In the method for manufacturing a ceramic substrate according to the present invention, the gas may include at least one of carbon fluoride and nitrogen fluoride.

Moreover, in the manufacturing method of the board | substrate for power modules which concerns on this invention, it is good also as using aluminum as said metal member.
According to the present invention, since generation of SiO gas together with Al ₂ O ₃ (alumina) is suppressed during bonding, the ceramic substrate and the metal member can be bonded with sufficient strength. That is, when joining a ceramic substrate and a metal member, if silicon oxide or a composite oxide of silicon exists on the surface of the ceramic substrate, alumina, which is an oxide of aluminum, at the interface with the ceramic substrate in the vicinity of the metal member. As it is formed, silicon monoxide gas is generated, but silicon oxide and silicon composite oxide on the surface of the ceramic substrate are well removed by surface treatment, so generation of silicon monoxide gas during bonding is suppressed. Has been.

Further, since no fluoride remains on the surface of the ceramic base material after dry etching, generation of AlF ₃ (aluminum fluoride) on the surface is prevented, and the ceramic substrate and the metal member are caused by AlF _3. The bonding strength with is not reduced. Therefore, sufficient bonding strength between the ceramic substrate and the metal member is ensured.

In the method for manufacturing a power module substrate according to the present invention, the ceramic substrate and the metal member may be joined by brazing.
In the present invention, the ceramic substrate and the metal member are joined by brazing.

  According to the method for manufacturing a ceramic substrate and the method for manufacturing a power module substrate according to the present invention, sufficient bonding strength can be obtained when a ceramic substrate containing Si and a metal member are bonded, and during a thermal cycle. The bonding reliability in the is improved.

  Embodiments of a method for manufacturing a ceramic substrate and a method for manufacturing a power module substrate according to the present invention will be described below with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a power module substrate according to the first embodiment of the present invention, and FIG. 2 shows an electronic probe microanalyzer used as the ceramic substrate for the power module substrate of the first embodiment of the present invention. FIG. 3 is a flowchart illustrating a method for manufacturing a power module substrate according to the first embodiment of the present invention, and FIG. 4 is a power module substrate according to the first embodiment of the present invention. It is sectional drawing which shows schematic structure of a power module provided with.

  As shown in FIG. 1, the power module substrate 1 in this embodiment is disposed on a ceramic substrate 11, a metal layer (metal member) 12 disposed on the lower surface of the ceramic substrate 11, and an upper surface of the ceramic substrate 11. A plurality of circuit layers (metal members) 13 are provided. That is, a metal member is bonded to the surface so that the ceramic substrate 11 is sandwiched from above and below.

The ceramic substrate 11 is made of Si ₃ N ₄ (silicon nitride) containing Si (silicon) and is formed in a plate shape.
Further, the concentration of silicon oxide and silicon composite oxide on the upper and lower surfaces of the ceramic substrate 11 is 2.7 Atom% or less in surface measurement using EPMA (Electron Probe Microanalyzer).

Here, a surface measurement method using EPMA will be described with reference to FIG.
The quantitative analysis result shown in FIG. 2 is an example used to explain the surface measurement method.
In this embodiment, JXA-8600 manufactured by JEOL is used, the operating pressure is 1.3 × 10 ⁻³ Pa, the acceleration voltage is 15.0 kV, and the current supplied to the probe is 5.0 × 10 ⁻⁸ A. It is said. Further, an Au film having a film thickness of less than 100 nm is formed on the surface of the ceramic substrate 11 by vapor deposition.

First, the surface of the ceramic substrate 11 is quantitatively analyzed under the above conditions (A shown in FIG. 2A). And the detection amount of C (carbon) and Au (gold) among the elements detected by the quantitative analysis is set to 0 (B shown in FIG. 2A). Further, conversion is performed so that the sum of the detected amounts of other elements excluding C and Au is 100 Atom% (C shown in FIG. 2A).
Next, metal elements other than Si (silicon) are the most common oxides (for example, Al ₂ O ₃ (alumina), Y ₂ O ₃ (yttrium oxide), MgO (magnesium oxide), Er ₂ O ₃ (oxidation). 2), the atomic weight of O (oxygen) bonded to a metal element other than Si is calculated (FIG. 2B).
Subsequently, the difference between the converted atomic weight of O and the atomic weight of O bonded to a metal element other than Si is calculated. The calculated total amount of O is combined with Si to constitute SiO ₂ , and the value obtained by multiplying the calculated atomic amount of O by 1.5 is the SiO ₂ concentration on the surface of the ceramic substrate 11. . For example, in the example of quantitative analysis results shown in FIG. 2, the SiO ₂ concentration is 0.253 Atom%.
In addition, the surface measurement using EPMA is measured in arbitrary five places on the upper surface of the ceramic substrate 11. Here, the surface measurement is not limited to 5-point measurement, and may be 10-point measurement or other plural places.

The metal layer 12 is formed of a metal having a high thermal conductivity such as Al (aluminum), and is bonded to the ceramic substrate 11 by a brazing material layer 14.
The circuit layer 13 is formed of a metal having a high thermal conductivity such as Al, for example, similarly to the metal layer 12, and constitutes a circuit by being appropriately spaced. The circuit layer 13 is bonded to the ceramic substrate 11 by the brazing material layer 15.
An electronic component 16 is fixed to the upper surface of the circuit layer 13 with a solder layer 17. Examples of the electronic component 16 include a power device such as an IGBT (Insulated Gate Bipolar Transistor).

Next, a method for manufacturing the power module substrate 1 having the above configuration will be described with reference to FIG.
First, a ceramic base material made of Si ₃ N ₄ which is a base material of the ceramic substrate 11 and has substantially the same shape as the ceramic substrate 11 is prepared, and this ceramic base material is fired (sintered) as shown in S10. (Sintering process). On the surface of the ceramic base material after sintering, silicon oxide made of Si and a composite oxide of silicon generated during sintering are present.

Next, as a surface treatment step, as shown in S20, dry etching is performed on the surface of the ceramic base material by plasma etching or reactive ion etching using a gas containing fluoride ions. The gas is configured by mixing a main gas, a sub gas, and a carrier gas. Specifically, the main gas is carbon fluoride (C _n F _{2n + 2} , C _n F _2n, etc.), nitrogen fluoride (NF) ₃ ), the secondary gas is H ₂ , SF ₆ (sulfur hexafluoride) or a rare gas, and the carrier gas is Ar ⁺ , Ne ⁺ , He ⁺ (as an ion beam).

Note that when H ₂ is used as the sub-gas, the etching rate ratio of SiO ₂ can be reliably increased, and when SF ₆ is used, SF ₅ ⁺ becomes the carrier gas. Further, when a rare gas is used as the auxiliary gas, the SiO ₂ etching rate ratio can be increased by lowering the fluorine concentration of the gas.

In the surface treatment process, the SiO _{2 on} the surface of the ceramic base material reacts with the gas to mainly become SiF ₄ and NOx or COx, which is gasified and removed from the surface of the ceramic base material. Thus, silicon oxide and silicon composite oxide on the surface of the ceramic base material are removed with high accuracy.

When hydrogen is contained in the gas, NH ₄ F and (NH ₄ ) ₂ SiF ₆ are formed on the surface of the ceramic base material. These NH ₄ F and (NH ₄ ) ₂ SiF ₆ are It is preferable to remove in a subsequent step.
Although not shown, after the surface treatment process, it is preferable to clean the ceramic base material in a distilled water cleaning process, air blow dry in a drying process, and further clean in an ultrasonic cleaning process using ethanol.

Next, as a surface measurement step, as shown in S30, the concentration of silicon oxide and silicon composite oxide on the surface of the ceramic base material after the surface treatment step is measured by EPMA to confirm that it is 2.7 Atom% or less. To do. The surface measurement method using EPMA is the same as described above. Moreover, the surface measurement by EPMA is measured in arbitrary five places on the surface of the ceramic base material.
If the result of the surface measurement step is 2.7 Atom% or less, the production of the ceramic substrate 11 is finished, and the process proceeds to the next step.
When the result of the surface measurement process exceeds 2.7 Atom%, the surface treatment process of S20 is performed again on the ceramic base material.

Next, as a metal member joining step for manufacturing the power module substrate 1, as shown in S40, the metal members of the metal layer 12 and the circuit layer 13 are integrally bonded to the upper and lower surfaces of the ceramic substrate 11 by brazing. Join.
The power module substrate 1 is manufactured as described above.

  As described above, on both the upper and lower surfaces of the ceramic substrate 11 of the power module substrate 1, the silicon oxide and the silicon composite oxide are accurately removed in the surface treatment step of S20. And generation of SiO (silicon monoxide) gas resulting from the composite oxide of silicon is suppressed.

That is, in the surface treatment step, the silicon oxide and silicon composite oxide on the surface of the ceramic base material react with fluoride ions to be removed from the surface as a highly volatile SiF ₄ gas, etc. In addition, the concentration of the complex oxide of silicon is reliably reduced to 2.7 Atom% or less in the surface measurement. Therefore, when the ceramic substrate 11 manufactured in this way and the metal member are joined, generation of SiO gas due to silicon oxide and silicon composite oxide is suppressed, so that the circuit layer 13 and the ceramic substrate are prevented. 11 and the bonding area between the metal layer 12 and the ceramic substrate 11 are sufficiently secured, and the ceramic substrate 11 and the metal member are prevented from being peeled off during the thermal cycle, so that the bonding reliability is improved. Has been enhanced.

In addition, fluoride ions contained in the dry etching gas become highly volatile SiF ₄ gas due to the above-described reaction, and therefore do not remain as fluoride on the surface of the ceramic base material. Further, since dry etching has less wraparound of the reaction as compared with, for example, wet etching of a ceramic base material, it is possible to suppress fluoride from remaining in response to the sintering aid more than necessary.

In dry etching, SiO ₂ on the surface of the ceramic base material is removed by etching, and when Si ₃ N ₄ is reached, the etching reaction is suppressed, so that only SiO ₂ can be efficiently removed.
Therefore, when the ceramic substrate 11 and the metal member are bonded, it is possible to prevent a bonding failure from occurring due to the fluoride, and the bonding reliability between the ceramic substrate 11 and the metal member is reliably increased. .

In addition, since generation of SiO gas together with Al ₂ O ₃ is suppressed during bonding, the ceramic substrate 11 and the metal member can be bonded with sufficient strength. That is, when the ceramic substrate 11 and the metal member are joined, if silicon oxide or a composite oxide of silicon exists on the surface of the ceramic substrate 11, an aluminum oxide is present at the interface between the metal member and the ceramic substrate 11 and in the vicinity thereof. A certain amount of alumina is formed and silicon monoxide gas is generated, but silicon oxide and silicon composite oxide on the surface of the ceramic substrate 11 are well removed by the surface treatment. Is suppressed.

Further, since no residual fluoride on the surface of the ceramic base 11 after dry etching, AlF 3 _(aluminum fluoride) is prevented from being generated in the surface, the ceramic substrate 11 due to AlF ₃ The bonding strength with the metal member is not reduced. Therefore, sufficient bonding strength between the ceramic substrate 11 and the metal member is ensured.

  In the power module substrate 1 having such a configuration, since the bonding area and the bonding strength between the ceramic substrate 11 and the metal member are sufficiently ensured, the circuit layer can be used for up to, for example, about 1000 cycles in the temperature cycle test. 13 and the metal layer 12 are reliably suppressed from peeling from the ceramic substrate 11.

Note that the surface measurement step of S30 described in FIG. 3 may be omitted when the measurement result is stably obtained at 2.7 Atom% or less.
Moreover, it is more preferable that the surface treatment process of S20 is performed immediately before joining of the metal member joining process of S40.
In addition, when the result of the surface measurement step of S30 exceeds 2.7 Atom%, the ceramic base material may be discarded without performing the surface treatment step of S20 again as described above. It can be selected according to the application.

The power module substrate 1 manufactured in this way is used for a power module 30 as shown in FIG. 4, for example. The power module 30 includes the power module substrate 1, the electronic component 16, a cooler 31, and a heat sink 32.
The cooler 31 is a water-cooled heat sink, and a flow path through which cooling water as a coolant flows is formed.
The heat radiating plate 32 has a substantially rectangular flat plate shape in plan view, and is formed of, for example, Al, Cu (copper), AlSiC (aluminum silicon carbide), Cu—Mo (molybdenum), or the like.

  And the heat sink 32 is being fixed with the screw | thread 33 with respect to the cooler 31 via heat conductive grease. Further, the heat sink 32 and the metal layer 12 of the power module substrate 1 are joined by a solder layer 34. In addition, the heat sink 32 and the metal layer 12 may be joined by brazing. At this time, when the power module substrate 1 is manufactured, the respective members may be brazed together in a state in which the radiator plate 32 is further laminated on the laminate of the metal layer 12, the ceramic substrate 11, and the circuit layer 13. Further, the power module 30 may have a configuration in which the power module substrate 1 is provided on the upper surface of the cooler 31 without providing the heat radiating plate 32.

Next, the manufacturing method of the board | substrate for power modules of the 2nd Embodiment of this invention is demonstrated, referring FIG.
FIG. 5 is a process diagram illustrating a method for manufacturing a power module substrate according to the second embodiment of the present invention.
In addition, the same code | symbol is attached | subjected to the same member as the above-mentioned 1st Embodiment, and the description is abbreviate | omitted.

First, a ceramic base material 20 made of Si ₃ N ₄ and fired (sintered) is prepared. On the surface of the ceramic base material 20, silicon oxide made of Si generated during sintering and a composite oxide of silicon are present. A plurality of scribe lines 21 are formed on one surface of the ceramic base material 20 as shown in FIG.

Here, a linear scribe line 21 is formed by irradiating one surface of the ceramic base material 20 with laser light (energy light) L. At this time, the fumes 22 scattered from the ceramic base material 20 by the irradiation of the laser beam L adhere to the formation region of the scribe line 21 and the vicinity thereof. The fume 22 is also formed of silicon oxide and a composite oxide of silicon because the ceramic base material 20 is made of Si ₃ N ₄ .

Next, as a first surface treatment, a blast treatment is performed in which ZrO ₂ (zirconium dioxide) powder is sprayed onto the upper and lower surfaces of the ceramic base material 20 (FIG. 5B). Thereby, the upper and lower surfaces of the ceramic base material 20 are flattened, and the fumes 22 attached to one surface of the ceramic base material 20 are removed.

  Next, as a second surface treatment, as shown in FIG. 5C, the ceramic base material 20 from which the fume 22 has been removed is accommodated in a container-like dry etching apparatus P, and fluoride ions are put into the dry etching apparatus P. The gas G containing it is introduced and dry etching is performed. The gas G is configured by mixing the main gas, the sub gas and the carrier gas described above.

The gas G reacts mainly with the silicon oxide and silicon composite oxide on the surface of the ceramic base material 20 to become SiF ₄ and NOx or COx, and these silicon oxide and silicon composite oxides come from the surface of the ceramic base material. While being removed, the exhaust gas E is discharged from the dry etching apparatus P. Thus, the silicon oxide and the silicon composite oxide on the surface of the ceramic base material 20 are accurately removed by dry etching.

When the gas G contains hydrogen, NH ₄ F and (NH ₄ ) ₂ SiF ₆ are formed on the surface of the ceramic base material 20, and these NH ₄ F and (NH ₄ ) ₂ SiF ₆ are It is preferable to remove in a later step.
Although not shown, after dry etching, the ceramic base material 20 is cleaned in a distilled water cleaning process, air blow dried in a drying process, and further cleaned in an ultrasonic cleaning process using ethanol, and then stored in a dry atmosphere. It is preferable.

  The concentration of silicon oxide and silicon composite oxide on the surface of the ceramic base material 20 after dry etching is reduced to 2.7 Atom% or less in the surface measurement by EPMA. The surface measurement method using EPMA is the same as described above. Moreover, the surface measurement by EPMA is measured in arbitrary five places in each of the several area | region divided by the scribe line 21 in the ceramic base material 20. FIG.

Next, the ceramic base material 20 is divided along the scribe line 21 (FIG. 5D). In this way, the ceramic substrate 41 is manufactured. Then, the metal layer 12 and the circuit layer 13 are joined to the upper and lower surfaces of the manufactured ceramic substrate 41 by brazing (FIG. 5E).
The power module substrate 51 is manufactured as described above.

As described above, the power module substrate 51 including the ceramic substrate 41 of the present embodiment also has the same effects as the first embodiment described above.
In the power module substrate 51 having such a configuration, since the bonding area and the bonding strength between the ceramic substrate 41 and the metal member are sufficiently ensured, the circuit layer is formed during, for example, about 1000 cycles in the temperature cycle test. 13 and the metal layer 12 are reliably prevented from peeling from the ceramic substrate 41.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the method for manufacturing a ceramic substrate according to the second embodiment, the scribe line 21 is provided in the sintered ceramic base material 20 and the fume 22 generated when the scribe line 21 is formed is removed by blasting. However, the present invention is not limited to this. That is, the ceramic base material 20 is cut into a plurality of ceramic substrates 41 by using a cutter or the like instead of the scribe line 21, and the blasting process described above may be omitted.

  In the first and second embodiments, the concentration of the silicon oxide and the silicon composite oxide on the upper and lower surfaces of the ceramic substrates 11 and 41 is set to 2.7 Atom% or less. The concentration of silicon oxide and silicon composite oxide in the surface portion to which the metal member is bonded may be 2.7 Atom% or less. That is, in the ceramic substrates 11 and 41, the concentration of silicon oxide and silicon composite oxide may be 2.7 Atom% or less only on the surface portion corresponding to the shape of the metal member to be bonded.

In the first and second embodiments, the circuit layer 13 is bonded with one surface of the ceramic substrates 11 and 41 as the upper surface. However, the metal layer 12 may be bonded with the one surface as the lower surface.
In addition, the ceramic substrates 11 and 41 and the circuit layer 13 or the metal layer 12 have been described as being brazed, but they may be bonded by other methods.

In the second embodiment, the ceramic base material 20 is divided and the ceramic substrate 41 is formed, and then the metal layer 12 and the circuit layer 13 are joined. However, the ceramic base material 20 on which the scribe line 21 is formed is bonded to the ceramic base material 20. The ceramic substrate 41 may be formed by dividing the ceramic base material 20 after joining at least one of the metal layer 12 and the circuit layer 13.
Moreover, although the scribe line 21 is formed by irradiating the laser beam L, it may be formed by irradiating other energy light.

Further, as the first surface treatment when the scribe line 21 is formed, other processing such as honing treatment may be used in addition to the blasting treatment by spraying powder.
Further, the metal layer 12 and the circuit layer 13 have been described as being formed of aluminum, but may be formed of other metal materials.

Further, the power module substrates 1 and 51 have the metal layer 12 bonded to the lower surfaces of the ceramic substrates 11 and 41, but without the metal layer 12, the heat sink 32 and the cooler are formed on the lower surfaces of the ceramic substrates 11 and 41. 31 may be directly joined.
The cooler 31 is not limited to the water-cooled type of the present embodiment, and may be an air-cooled type or other liquid-cooled type.

Further, the ceramic substrate 11 and 41 has been described as consisting of Si ₃ N ₄ containing Si, it is not limited thereto, but may be any other material containing Si.

The first, in the second embodiment, the gas used for dry etching, the main gas is carbon fluoride _{(C n F 2n + 2,} C n F 2n , etc.), from at least one of nitrogen fluoride (NF _3, etc.) It has been described that the auxiliary gas is made of H ₂ , SF ₆ (sulfur hexafluoride) or a rare gas, but is not limited thereto.

It is sectional drawing which shows schematic structure of the board | substrate for power modules which concerns on the 1st Embodiment of this invention. It is a table | surface which shows the result of having quantitatively analyzed the ceramic substrate used for the board | substrate for power modules concerning the 1st Embodiment of this invention with the electronic probe microanalyzer. It is a flowchart explaining the manufacturing method of the board | substrate for power modules which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows schematic structure of a power module provided with the board | substrate for power modules which concerns on the 1st Embodiment of this invention. It is process drawing explaining the manufacturing method of the board | substrate for power modules which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1,51 Power module substrate 11, 41 Ceramic substrate 12 Metal layer (metal member)
13 Circuit layer (metal member)
14, 15 Brazing material layer 20 Ceramic base material G Gas P Dry etching equipment S10 Sintering process S20 Surface treatment process (dry etching)
S30 Surface measurement process S40 Metal member joining process

Claims (5)

Sintering a ceramic matrix containing Si;
A surface treatment step of performing dry etching on the surface of the ceramic base material using a gas containing fluoride ions;
And a step of adjusting the concentration of silicon oxide and silicon composite oxide on the surface of the ceramic base material to 2.7 Atom% or less by surface measurement using an electron probe microanalyzer. . A method for producing a ceramic substrate according to claim 1, comprising:
The method for manufacturing a ceramic substrate, wherein the gas contains at least one of carbon fluoride and nitrogen fluoride.   A step of sintering a ceramic base material containing Si, a surface treatment step of performing dry etching on the surface of the ceramic base material using a gas containing fluoride ions, and silicon oxide and silicon on the surface of the ceramic base material A metal member is bonded to a ceramic substrate manufactured by a step of setting the concentration of the composite oxide of 2.7 Atom% or less by surface measurement using an electron probe microanalyzer A method for manufacturing a substrate. It is a manufacturing method of the board for power modules according to claim 3,
The manufacturing method of the board | substrate for power modules characterized by using aluminum as said metal member. A method for producing a power module substrate according to claim 3 or 4,
A method of manufacturing a power module substrate, wherein the ceramic substrate and the metal member are joined by brazing.

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