WO2017065407A1 - Ceramic circuit board and manufacturing method therefor - Google Patents

Abstract

The present invention relates to a ceramic circuit board and a manufacturing method therefor, the ceramic circuit board comprising: a ceramic substrate; a base metal layer formed on the ceramic substrate and including NiCr; and a conductive layer formed on the base metal layer, wherein a weight ratio of Ni:Cr of the base metal layer is 90:10 to 75:25. When the ceramic circuit board of the present invention is used, adhesion strength is enhanced such that the metal layer is not separated from the ceramic circuit board even when the ceramic circuit board is repetitively used by applying a current thereto for a long time, thereby enabling reliability to be enhanced, and thus an electronic part element having a large caloric value, such as a high-brightness LED, a photovoltaic power generation device, or an electronic part for a hybrid vehicle, can be safely loaded thereon.

Description

Ceramic Circuit Board and Manufacturing Method Thereof

The present invention relates to a ceramic circuit board used in high-brightness LEDs, photovoltaic devices, electronic components for hybrid vehicles, and the like, and a method of manufacturing the same.

Ceramic has high heat resistance, high mechanical strength and high insulation resistance, so that a high voltage is applied or a high output semiconductor device substrate is used. In order to use it as a substrate material, a conductive layer must be formed on the ceramic surface. Examples of the conductive layer include a chemical plating method (electroless plating), an electrolytic plating method, and an electrode paste printing method.

The chemical plating method refers to a method of forming a conductive layer on the surface of a ceramic by immersing the ceramic in a chemical plating solution.The electroplating method involves depositing a conductive metal layer on the surface of a ceramic and then conducting the current by immersing the ceramic in an electrolytic plating solution. The method of plating a conductive layer, and the electrode paste printing method is a method of printing a paste directly on a substrate and baking to form an electrode, which is excellent in bonding strength between the substrate and the paste.

In addition to the above methods, another method of depositing a metal on the ceramic surface may be sputtering or CVD. Sputtering is a method of ionizing a target material in a vacuum plasma state and depositing it on a ceramic substrate. In a high vacuum state, a target material is supplied in a gas state and deposited on a heated ceramic substrate.

Devices that emit a significant portion of power consumption as heat, such as high-brightness LEDs, must be capable of efficient heat dissipation, which can form holes in the ceramic substrate. In this case, a hole formed in the ceramic substrate is filled with an electrode material to apply a via hole method, and then a conductive layer is formed. The electroplating method or the paste printing method may be applied to the conductive layer formation. In the case of forming a hole in the ceramic substrate and applying a via hole method to form a conductive layer, holes are formed and the electrode material is filled in the holes so as to enhance adhesion between the semiconductor element to be formed on the ceramic substrate and the ceramic substrate. Various methods for forming a conductive layer have been attempted.

[Preceding technical literature]

[Patent Documents]

Korean Patent Publication No. 2014-0001735

Japanese Patent Laid-Open Publication 2013-143411

U.S. Patent 6,800,211

Japanese Patent No. 3,570,407

The present invention is to provide a ceramic circuit board having a base metal layer capable of increasing the adhesion strength between the substrate and the semiconductor device mounted in the manufacture of a ceramic circuit board for mounting a semiconductor device, and a method of manufacturing the same.

Ceramic circuit board according to an aspect of the present invention,

Ceramic substrates;

A base metal layer formed on the ceramic substrate and including NiCr; And

Containing a conductive layer formed on the base metal layer, the weight ratio of Ni: Cr of the first metal layer is 90:10 to 75:25.

In one embodiment of the present invention, the base metal layer may include a first metal layer including NiCr, and a second metal layer formed on the first metal layer to improve contact between the conductive layer and the ceramic substrate. The second metal layer may include Cu.

In addition, in one embodiment of the present invention, the ceramic substrate is at least one compound selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ) and silicon carbide (SiC). In addition, the ceramic substrate may be provided with a plurality of via holes, but the average diameter of the via holes may be about 200 μm or less. In addition, the thickness of the first metal layer is in the range of 0.015 to 0.2㎛, the thickness of the second metal layer is in the range of 0.05 to 0.5㎛, thereby having excellent thermal characteristics, it is possible to implement a precise circuit pattern.

Further, in another embodiment of the present invention, the conductive layer includes at least one metal selected from the group consisting of Cu, Au, Ni, and Ag.

In addition, the ceramic circuit board of the present invention may be equipped with an electronic component on the substrate, the electronic component includes a light emitting diode (LED), although not particularly limited thereto.

According to another aspect of the present invention, a method of manufacturing a ceramic circuit board is provided as follows.

(i) forming a first metal layer comprising NiCr having a weight ratio of Ni: Cr of 90:10 to 75:25 on the ceramic substrate;

(ii) forming a second metal layer over the first metal layer; And

(iii) forming a conductive layer on the second metal layer.

Here, the ceramic substrate may have a plurality of via holes having a diameter of about 200 μm or less formed by punching, drilling laser, or the like, the second metal layer may include Cu, and the conductive layer may include Cu, Au, Ni, and the like. It may include one or more metals selected from the group consisting of Ag.

In addition, the first metal layer and the second metal layer may be formed by a sputtering method, a printing method or a chemical plating method, and among them, the first metal layer and the second metal layer may be formed by a DC sputtering method from the viewpoint of the improvement of the film formation speed and the ease of thickness control.

In addition, as described above, the thickness of the first metal layer may be in the range of 0.015 to 0.2 μm, and the thickness of the second metal layer may be in the range of 0.05 to 0.5 μm.

In the case of using the ceramic circuit board of the present invention, since the adhesion strength is improved and the metal layer is not separated from the ceramic circuit board even after repeated application for a long time, the reliability can be improved. It is possible to safely mount electronic component elements having a large amount of heat generation, such as electronic components for hybrid automobiles.

1 (a) and (b) show a cross section of a ceramic circuit board of the present invention obtained by depositing a base metal layer that can be energized on a surface of a ceramic substrate, depositing it in an electrolytic plating solution, and then energizing and plating a conductive layer. Conceptual diagram.

2A and 2B are conceptual views illustrating a cross section of a substrate on which a base metal layer and a conductive layer are formed on both sides of the ceramic substrate of the present invention.

3 is a view showing the adhesion strength test of the ceramic circuit board of the present invention.

Looking at the ceramic circuit board of the present invention in more detail as follows.

Ceramic circuit board 100 according to an embodiment of the present invention is formed on the ceramic substrate 101 and the ceramic substrate 101, as shown in Figure 1 (a) and the base metal layer 102 containing NiCr and the Containing a conductive layer 103 formed on the base metal layer, the weight ratio of Ni: Cr of the base metal layer may be 90:10 to 75:25. In addition, the ceramic circuit board according to another embodiment of the present invention may include a plurality of via holes 104 passing through the ceramic substrate 101 as shown in FIG. 1B.

According to another embodiment of the present invention, as shown in FIG. 2A, the ceramic circuit board 200 may be formed on both sides of the base metal layer 202 and the conductive layer 203 based on the ceramic substrate 201. As shown in FIG. 2B, a plurality of via holes 204 may be formed in the ceramic circuit board 200. In the above description of the drawings, the same reference numerals in the drawings correspond to the same members indicating the same function.

Hereinafter, each member of the ceramic circuit board of the present invention will be described with reference to FIG. 1 for convenience.

The base metal layer 102 may include a first metal layer including NiCr, and a second metal layer formed on the first metal layer to improve contact between the conductive layer and the ceramic substrate. The conductive layer may be formed as a conductive layer on the second metal layer, and the second metal layer may include Cu.

In the present specification, the first metal layer containing NiCr is referred to as a NiCr base metal layer, the second metal layer containing Cu as a Cu base metal layer, and the first and second metal layers are collectively referred to as a NiCr / Cu base metal layer.

The details of each of the elements constituting the ceramic circuit board 100 of the present invention will be described.

<Ceramic Substrate>

First, the material of the ceramic substrate 101 used in the present invention is not particularly limited thereto, but alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), or the like may be used. Among them, alumina or an aluminum nitride substrate having excellent thermal conductivity may be used in terms of low cost and excellent mechanical strength, but silicon nitride (Si ₃ N ₄ ) or silicon carbide (SiC) may be used.

<First and second metal layer (base metal layer)>

At least one metal layer of the first and second metal layers is formed on the ceramic substrate 101 by a sputtering method. There is also a method of depositing Cu directly on a ceramic substrate by sputtering, followed by electroplating. However, in this case, since the adhesive strength is low, the substrate and the electrode are easily separated. Deposit metal.

Examples of metal targets having good adhesive strength include Ti and NiCr, but when Ti and NiCr are used as base metals, they are easily oxidized in the air, thereby preventing Cu electroplating. Therefore, in one embodiment of the present invention, a method of using a metal having good adhesion to ceramics as a base metal as the first metal layer and using a metal capable of electroplating as a second metal layer while preventing oxidation of the first metal layer is used. Accordingly, in one embodiment of the present invention, the base metal layer (first metal layer) formed directly on the ceramic substrate 101 of the two types of base metals, and the base metal layer (second metal layer) formed on the first metal layer The structure of the base metal layer 102 of the layer was adopted.

In addition, according to one embodiment of the present invention, the weight ratio of Ni: Cr of the base metal layer (first metal layer) is 90:10 to 75:25, so that the ratio of Ni and Cr of NiCr having good adhesion to the substrate is different. By using the NiCr base metal layer having a weight ratio of the numerical range, the residue can be minimized after the progress of the process while minimizing the adhesion strength.

The thickness of the NiCr base metal layer, which is the first metal layer, may be 0.015 to 0.2 µm, and the thickness of the Cu base metal layer, which is the second metal layer, may be 0.05 to 0.5 µm.

The method for forming the base metal layer 102 is not particularly limited, but may be a sputtering method, a printing method, or a chemical plating method. The DC sputtering method may be used in view of high film growth rate and easy thickness control. Can be used.

In the DC sputtering method, the power is 1.0 to 2.0 kW, the voltage is 400 to 550 V, the current is 2.0 to 4.0 A, the amount of Ar is 100 to 300 sccm, and the pressure is 3.0 to 4.0 mTorr.

<Conductive layer>

In an exemplary embodiment of the present invention, after forming the base metal layer 102, which is the first and second metal layers, on the ceramic substrate using a sputtering method, an electroconductive layer 103 containing Cu or the like is electrolyzed on the second metal layer. It is formed using the plating method. In one embodiment of the present invention, although copper (Cu) is used as the material of the conductive layer 103, other materials having low electrical resistance, for example, gold (Au), silver (Ag), nickel (Ni), and the like. May be formed by an electroplating method.

As described above, the ceramic circuit according to the embodiment of the present invention improves the adhesion strength between the ceramic substrate 101 and the conductive layer 103 by using the NiCr / Cu base metal layer 102 as the first and second metal layers. The substrate 100 is suitable for mounting electronic component elements having a large amount of heat generation, such as high-brightness LEDs, photovoltaic devices, and hybrid electronic components.

According to one embodiment of the present invention, the manufacturing method of the ceramic circuit board 100 consists of the following steps.

(i) forming a first metal layer including NiCr having a weight ratio of Ni: Cr of 90:10 to 75:25 on a ceramic substrate in a range of 0.015 to 0.05 μm in thickness;

(ii) forming a second metal layer including Cu on the first metal layer within a thickness of 0.05 to 0.35 μm; And

(iii) forming a conductive layer over the second metal layer.

The ceramic substrate 101 may be made of one or more compounds selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), and silicon carbide (SiC), and the conductive Layer 103 may comprise one or more metals selected from the group consisting of Cu, Au, Ni, and Ag.

The adhesion strength of the ceramic circuit board manufactured by the above method and the ceramic circuit board manufactured by the conventional method was tested according to the type of ceramic substrate, and the adhesion test method used the peel test method as shown in FIG. 2. .

As shown in FIG. 3, the Cu plating is completed, and the ceramic substrate 301, the base metal layer 302, and the conductive layer 303 are melted at 300 ° C. in the ceramic specimen 300 sequentially stacked. It is a method of measuring the adhesion strength by melting the solder (glue) and attaching a Cu wire (metal foil, 304) matching the Cu plating pattern and pulling it toward the arrow shown in FIG.

In addition, the etching potential of the ceramic circuit board obtained in the present invention was measured. After the metal etching solution was maintained at a temperature between 50 to 55 ° C. in the heating mantle, the deposited metal layer ceramic substrate specimen was dipped in the etching solution for 3 minutes. , And the residual metal was measured and confirmed by the method of analyzing with a component analyzer.

Furthermore, the TCT (thermal cycle test) performance of the ceramic circuit board obtained in the present invention was measured. Specifically, the cycle was continuously rotated at a temperature of -55 ° C to 150 ° C. It calculated | required by the method of examining whether it appears.

Hereinafter, the present invention will be described in more detail based on the following examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited by these examples.

Example 1 and Comparative Examples 1 to 4 : adhesion strength comparison for alumina (Al ₂ O ₃ ) substrate

The ceramic circuit board manufacturing method according to the embodiment of the present invention described above was manufactured. As the ceramic substrate, an alumina substrate having a via hole was used.

When two base metal layers are used, the base metal layer adjacent to the ceramic substrate is referred to as base metal layer 1, and the base metal layer formed on the base metal layer 1 is referred to as base metal layer 2, and for example, "NiCr / Cu" and Likewise, the base metal layer 1 / base metal layer 2 was designated.

The thickness of the base metal layer 1 was 0.2 μm, the thickness of the base metal layer 2 was 0.1 μm, and the thickness of the Cu electroplating layer plated on the base metal layer 2 was 50 μm, which was the same in Examples and Comparative Examples. In Example 1 representing the ceramic circuit board of the present invention, a base metal layer of Ni _x Cr _{1- x} (x = 0.8) / Cu was used, and in Comparative Example 1, Ti / Cu, which is conventionally used, was used. In each case, only Cu and NiCr were used alone as the base metal layer, and in Comparative Example 4, NiCr / Ag was used as the base metal layer.

In addition, the base metal layer was a DC sputtering method, and before the sputtering, an ultrasonic cleaning process was performed to remove organic substances and impurities from the surface of the alumina substrate.

The DC sputtering was sputtered under conditions of a voltage of 450 V, a current of 3 A, an amount of Ar of 200 sccm, and a pressure of 3.5 mTorr, thereby forming a base metal layer having the thickness as described above.

The adhesion strength of each ceramic circuit board thus manufactured was measured by the above-described peel test method, and the results are shown in Table 1 below.

division	thickness	Example 1	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4
Base metal layer 1	0.2 μm	Ni x Cr 1 -x (x = 0.8)	Ti	Cu	Ni x Cr 1 -x (x = 0.8)	Ni x Cr 1 -x (x = 0.8)
Base metal layer 2	0.1 μm	Cu	Cu	-	-	Ag
Cu Electroplating	50 μm	○	○	○	No plating	○
Average adhesion strength (N / mm)		21.4	10.3	1.0	-	7.8
Etchability		O	O	O	O	O

As shown in Table 1 above, when NiCr / Cu is used as the base metal layer, the average adhesion strength is improved to 21.4 N / mm, compared to 10.3 N / mm when Ti / Cu is used as the base metal layer. It was found. In addition, when only Cu was deposited as the base metal layer, the adhesion strength was very low. When only NiCr was deposited as the base metal, Cu did not plate. In addition, in the case of Comparative Example 4 using NiCr as the base metal layer 1 and Ag instead of Cu as the base metal layer 2 as in the present invention, the adhesion strength was 7.8 N / mm and the adhesive strength was 1/3 compared to the present invention. It was only about.

Example 2 and Comparative Example 5-6 : Comparison of adhesion strength to aluminum nitride (AlN) substrate

The adhesion strength of the ceramic substrate produced in the same manner as in Example 1 was measured except that the used ceramic substrate was replaced with aluminum nitride instead of alumina.

When the base metal layer was used as only one type of Cu or NiCr as in Comparative Examples 2 and 3, except when Ni _x Cr _{1- x} (x = 0.8) / Cu was used (Example 2), Ti / Cu The experiment was divided into the case of using (Comparative Example 5) and the case of using NiCr / Ag (Comparative Example 6).

Each adhesion strength to the aluminum nitride substrate is shown in Table 2 below.

division	thickness	Example 2	Comparative Example 5	Comparative Example 6
Base metal layer 1	0.2 μm	Ni x Cr 1 -x (x = 0.8)	Ti	Ni x Cr 1 -x (x = 0.8)
Base metal layer 2	0.1 μm	Cu	Cu	Ag
Cu Electroplating	50 μm	○	○	○
Average adhesion strength (N / mm)		20.1	15.2	6.0
Etchability		O	O	O

As shown in Table 2, it was found that the ceramic substrate using NiCr / Cu of the present invention as the base metal layer has excellent adhesion strength to the aluminum nitride substrate. On the other hand, in the case of using the conventional Ti / Cu base metal layer, it was found that the adhesion strength was 15.2 N / mm more than the adhesion strength on the alumina substrate, but was still insufficient level, NiCr / Ag base metal layer In case of use, 6.0 N / mm was poor as in the case of adhesion strength to alumina substrate.

Example 3-6 and Comparative Example 7-8 : Comparison of adhesion strength by Ni content in NiCr base metal layer

In the case of using the same alumina substrate as in Example 1, the experiment was performed once how the adhesion strength changes as the Ni content of the NiCr base metal layer changes.

The adhesion strength, the TCT and the degree of etching possibility in each case were measured in a weight ratio of Ni: Cr (Ni: Cr) in the range of 70:30 to 95: 5, and the results are shown in Table 3 below.

division	Comparative Example 7	Example 3	Example 4	Example 5	Example 6	Comparative Example 8
Ni content (%)	95	90	88	80	75	70
Cr content (%)	5	10	12	20	25	30
Average adhesion strength (N / mm)	8	18	23.5	25.8	32	35
Etchable	○	○	○	○	○	×
TCT (times)	10	90	100	150	155	160

As shown in Table 3, when the Ni content in the NiCr base metal layer was 75 to 90% by weight, the adhesion strength and the TCT result were excellent and the etching was also possible. The adhesion strength was found to be increased in proportion to the content of Cr. When the Cr content was 30% by weight, as in the case of Comparative Example 8, it was confirmed that the residue remained in the etching process after the pattern formation.

[Description of the code]

100, 200, 300 ceramic circuit board

101, 201, 301 ceramic substrate

102, 202, 302 base metal layer

103, 203, 303 conductive layer

304 Cu wire (metal foil)

Claims (18)

1. Ceramic substrates;

   A base metal layer formed on the ceramic substrate and including NiCr; And

   A conductive layer formed on the base metal layer,

   The weight ratio of Ni: Cr of the base metal layer is 90:10 to 75:25.
2. The method according to claim 1,

   The base metal layer is a ceramic circuit board comprising a first metal layer including NiCr, and a second metal layer formed on the first metal layer.
3. The method according to claim 2,

   The second metal layer is a ceramic circuit board containing Cu.
4. The method according to claim 1,

   The ceramic substrate is one or more compounds selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ) and silicon carbide (SiC).
5. The method according to claim 1,

   The ceramic substrate is a ceramic circuit board is provided with a plurality of via holes.
6. The method according to claim 2,

   The thickness of the first metal layer is a ceramic circuit board in the range of 0.015 to 0.2㎛.
7. The method according to claim 2,

   The thickness of the second metal layer is a ceramic circuit board in the range of 0.05 to 0.5㎛.
8. The method according to claim 1,

   The conductive layer is a ceramic circuit board of Cu, Au, Ni or Ag.
9. The method according to any one of claims 1 to 8,

   Ceramic circuit board on which the electronic component is mounted on the ceramic circuit board.
10. The method according to claim 9,

    The electronic component is a light emitting diode (LED) ceramic circuit board.
11. (i) forming a first metal layer comprising NiCr having a weight ratio of Ni: Cr of 95:05 to 75:25 on the ceramic substrate;

    (ii) forming a second metal layer over the first metal layer; And

    (iii) forming a conductive layer over the second metal layer

    Method of manufacturing a ceramic circuit board comprising a.
12. The method according to claim 11,

    The ceramic substrate is a method of manufacturing a ceramic circuit board made of at least one compound selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ) and silicon carbide (SiC). .
13. The method according to claim 11,

    The ceramic substrate is a method of manufacturing a ceramic circuit board is a plurality of via holes are formed.
14. The method according to claim 11,

    The second metal layer is a method of manufacturing a ceramic circuit board containing Cu.
15. The method according to claim 11,

    The conductive layer is a method of manufacturing a ceramic circuit board comprising at least one metal selected from the group consisting of Cu, Au, Ni and Ag.
16. The method according to claim 11,

    At least one of the first metal layer and the second metal layer is formed by a method selected from the group consisting of a sputtering method, a printing method and a chemical plating method.
17. The method according to claim 13,

    At least one of the first metal layer and the second metal layer is formed by a DC sputtering method.
18. The method according to claim 11,

    The thickness of the first metal layer is in the range of 0.015 to 0.2㎛, the thickness of the second metal layer is a method of manufacturing a ceramic circuit board in the range of 0.05 to 0.5㎛.

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