WO2017069398A1 - 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 layer disposed on the ceramic substrate; a bonding layer disposed on the base layer; and a metal foil disposed on the bonding layer.

Description

Ceramic Circuit Board and Manufacturing Method Thereof

The present invention relates to a ceramic circuit board and a method of manufacturing the same.

In recent years, as the performance of industrial devices such as robots and motors is advanced, and high power modules such as high power and high efficiency inverters are required, heat generated from semiconductor devices is also increasing. In order to dissipate this heat efficiently, various methods have been conventionally taken for the power module substrate. In particular, with the recent development of ceramic substrates having a good thermal conductivity, the development of modules has been progressed to a structure in which a semiconductor device is mounted after bonding a metal plate to a ceramic substrate and forming a circuit.

As an electrically insulating substrate used in such a semiconductor device, ceramic materials such as alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), zirconia (ZrO ₂ ) are conventionally used. It is used. There are various methods for bonding the metal and the substrate of the ceramic material as described above. For example, after placing the surface-oxidized copper sheet in contact with the ceramic substrate, the temperature is lower than the melting point of copper and higher than the eutectic point of copper and oxygen. Direct bonding copper (DBC) has been developed and commercialized in which copper oxide is directly bonded to a substrate by melting copper oxide by heating.

Recently, ceramic circuit boards manufactured by an active metal bonding method for joining metal circuit boards through a brazing filler metal layer have also been developed in order to maintain more heat dissipation and strong mechanical bonding properties, and have been applied to power semiconductors requiring high reliability. It is becoming. In the case of the active metal bonding method, since the bonding process temperature is lower than that of the direct bonding method, the residual stress of the metal-ceramic is small, and since the bonding layer is a soft metal, it is highly reliable against thermal shock and thermal changes, and is generated at the interface during bonding. Micro voids are less generated and have excellent electrical characteristics. However, in the case of the ceramic circuit board obtained by the active metal bonding method, a reaction layer is formed by the reaction with the ceramic when the active metal is bonded, and the structure of the reaction layer is weak, so that the mechanical strength is lowered. This is a major disadvantage in recent power modules.

In order to overcome the shortcomings of the active metal bonding method, a method of bonding a ceramic substrate and a metal plate through a solder paste is being studied, but bonding strength and other mechanical properties have not been sufficiently secured.

[Preceding technical literature]

[Patent Documents]

Japanese Patent Laid-Open No. 2001-168482

Korean Patent Publication No. 2013-0132684

The present invention provides a ceramic circuit board for component parts of a semiconductor device such as a power module substrate, comprising: a ceramic substrate, a base layer disposed on the ceramic substrate, a bonding layer disposed on the base layer, and the bonding layer; It includes a metal foil disposed, thereby providing a ceramic circuit board and a method of manufacturing the ceramic circuit board with improved properties such as TCT (thermal cycle test) performance, bonding strength, substrate warpage and VOID.

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

Ceramic substrates;

A base layer disposed on the ceramic substrate;

A bonding layer disposed on the base layer; And

It includes a metal foil disposed on the bonding layer.

It is sufficient that each member of the ceramic circuit board according to an embodiment of the present invention is "arranged" as long as the member is disposed above the member below it, and other members ( E.g., including other functional layers) is not excluded.

In one embodiment of the present invention, the ceramic substrate is selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC) and zirconia (ZrO ₂ ). At least one, and the base layer includes at least one selected from the group consisting of Cu, Ni, Cr, Ti, W, Mn, and Mo.

On the other hand, the thickness of the base layer is in the range of 0.015 to 0.5㎛, the metal foil includes one or more selected from the group consisting of Cu, Au, Ni and Ag, the thickness of the metal foil is 100 to 600㎛ In range

In addition, according to one embodiment of the present invention, although not particularly limited thereto, the surface roughness Rz of at least one surface of the metal foil, more specifically, both surfaces, may be 2.0 μm or less.

Moreover, according to one embodiment of the present invention, the bonding layer contains at least one member selected from the group consisting of Cu, Sn, Ni, P, Ag, Zn, Ti, In.

The bonding layer is a composition,

60 to 80 parts by weight of Cu,

Sn 10 to 30 parts by weight,

P 3 to 15 parts by weight,

In 3 to 15 parts by weight, and

An organic vehicle residue, wherein the organic vehicle comprises at least one organic solvent selected from methanol, ethanol, terpineol, texanol, toluene, and the like, and optionally at least one organic binder of cellulose and acrylic do.

In addition, although not particularly limited thereto, the thickness of the bonding layer is in the range of 5 to 100 μm.

In addition, the electronic component may be mounted on the ceramic circuit board of the present invention, and may be used in industrial fields such as power modules.

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

Placing a base layer on a ceramic substrate,

Disposing a bonding layer on the base layer,

Disposing a metal foil on the bonding layer;

And performing at least one of energy ray irradiation and heat treatment on the base layer, the bonding layer, and the metal foil on the ceramic substrate.

In the above, at least one of the base layer and the bonding layer is formed by a method selected from the group consisting of a sputtering method, a printing method and a chemical plating method, and among them, may be formed by a DC sputtering method.

The bonding layer, as described above, comprises 60 to 80 parts by weight of Cu, 10 to 30 parts by weight, P 3 to 15 parts by weight, In 3 to 15 parts by weight, and the organic vehicle balance, wherein the organic vehicle is methanol , At least one organic solvent selected from the group consisting of ethanol, terpineol and toluene, and optionally at least one organic binder of cellulose and acrylic.

In addition, the heat treatment in the step may be performed at a temperature range of 300 ℃ to 900 ℃.

In the case of using the ceramic circuit board of the present invention, the mechanical strength such as bonding strength, substrate warpage amount, TCT and VOID characteristics are improved, and thus the bonding strength is not exfoliated by shrinkage-expansion due to repeated heat release. And it can be applied to industrial fields such as power module that requires thermal reliability.

1 is a cross-sectional view showing a cross-sectional shape of a ceramic circuit board according to an embodiment of the present invention.

2 is a cross-sectional view showing a cross-sectional shape of a ceramic circuit board according to still another embodiment of the present invention.

Referring to FIG. 1, a ceramic circuit board 100 according to an exemplary embodiment of the present invention includes a ceramic substrate 101, a base layer 102 disposed on the ceramic substrate 101, and the base layer 102. The bonding layer 103 arrange | positioned on and the metal foil 104 arrange | positioned on the said bonding layer 103 is included.

Also, referring to FIG. 2, the ceramic circuit board 200 according to another embodiment of the present invention may include a structure of a base layer / bonding layer / metal foil on both sides as well as one side of the ceramic substrate 201. Specifically, the bonding layer 203 disposed on the base layer 202 and the base layer 202 and the metal foil 204 disposed on the bonding layer 203, respectively, on both surfaces of the ceramic substrate 201. ) May be included.

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

<Ceramic Substrate>

First, the material of the ceramic substrate 101 used in the present invention is not particularly limited thereto, but may include alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), and zirconia. (ZrO ₂ ), and the like, among these, an alumina substrate having excellent inexpensive and excellent mechanical strength or an aluminum nitride substrate having excellent thermal conductivity can be used. Although the thickness of the ceramic substrate 101 is not specifically limited, The range of 0.2 mm-1.0 mm which is the thickness of the ceramic substrate normally used can be used.

<Base layer>

In forming the base layer 102 having excellent adhesion with the ceramic substrate 101, at least one of Cu, Ni, Cr, Ti, W, Mn, or Mo is used by sputtering, printing, or chemical plating. The base layer 102 is formed. Examples of the base layer 102 include NiCr-Cu, Ti-Cu, Cu, W, Mn, Mo, and the like. Although the thickness of the base layer 102 is not particularly limited thereto, according to one embodiment of the present invention, the thickness of the base layer 102 may be in the range of 0.015 to 0.5 μm. If the thickness of the base layer 102 is less than 0.015 μm, the thickness thereof is too high. The thinness may impair adhesion to the ceramic substrate, and if the thickness of the base layer 102 is greater than 0.5 μm, the thickness may be too large and may adversely affect the thickness of the substrate and increase unnecessary resistance. In addition, the DC sputtering method may be used in the method of forming the base layer 102 in terms of high film growth rate and easy thickness control.

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

<Metal foil and bonding layer>

After the base layer 102 (eg, NiCr / Cu) is formed on the ceramic substrate 101 by a sputtering method or the like, the bonding layer 103 is disposed on the base layer 102, and then the bonding layer 103 is formed. ), The metal foil 104 and the ceramic substrate are joined by arranging and bonding the metal foil 104 on the wafer).

The metal foil 104 is Cu, Au, Ni or Ag, the thickness of the metal foil is preferably in the range of 100 to 600㎛, if the thickness of the metal foil 104 is less than 100㎛ its thickness is too thin metal foil 104 The thickness of the metal foil 104 may be greater than 600 μm, and the efficiency of the ceramic circuit board 100 may decrease due to an increase in resistance () due to an increase in the thickness of the metal foil 104. Adhesion of the section 103 may be lowered. By setting the thickness of the metal foil 104 according to one embodiment of the present invention to 100 to 600 µm or less, the durability of the substrate produced by maximizing the adhesive force with the bonding layer 103 can be improved.

The bonding layer 103 is a layer formed of a composition including Cu, Sn, P, In, and an organic vehicle, and directly prints the composition on the base layer 102 disposed on the ceramic substrate 101, or the base The composition is preformed in a predetermined shape on the layer 102 and placed (interposed) in a preform, and then the metal foil 104 is integrally disposed thereon to perform brazing, wherein the temperature depends on the material of the bonding layer 103. Although different, it can be carried out at approximately 300 ℃ to 900 ℃.

The metal foil 104 used in the present invention is substantially not subjected to roughening treatment by forming a lump-shaped electrodeposition layer, or by performing an oxidation treatment, a reduction treatment, or an etching in order to improve adhesion to the metal foil 104 surface. will be. The term "substantially" means that the metal foil subjected to the roughening treatment can be used to such an extent that sufficient adhesive strength cannot be obtained, and a metal foil without any roughening treatment may be used. Therefore, the surface roughness of the metal foil used in the present invention may be 3.0 µm or less, 2.0 µm or less, or 0.3 µm or less on both sides of the 10-point average roughness Rz shown in JIS B0601. By arrange | positioning the metal foil which has such a smooth surface using the following bonding layer, the metal foil which concerns on this invention can ensure sufficient adhesive force etc. with a ceramic substrate.

The bonding layer 103 according to the present invention is composed of 60 to 80 parts by weight of Cu, 10 to 30 parts by weight of Sn, 3 to 15 parts by weight, 3 to 15 parts by weight of In, and the remainder of the organic vehicle. The organic vehicle can include, for example, an organic solvent, and optionally an organic binder. The organic solvent is not limited thereto, but organic solvents such as methanol, ethanol, terpineol, toluene, and the like may be used. As the organic binder, cellulose or acrylic organic binders such as ethyl cellulose and methyl cellulose may be used for handling. .

According to one embodiment of the invention, the thickness of the bonding layer 103 may be in the range of 5 to 100㎛. If the thickness of the bonding layer 103 is less than 5 μm, there is a problem in the adhesion between the base layer 102 and the metal foil 104. If the thickness of the bonding layer 103 is more than 100 μm, the bonding layer 103 is thick. Due to the difficulty in heat transfer from the metal foil 104 to the ceramic substrate 101, the efficiency of the ceramic circuit board 100 is lowered.

The bonding layer 103 is disposed between the base layer 102 and the metal foil 104, and is formed by the energy ray irradiation and / or heat treatment of the bonding layer 103 or the bonding layer 103 and the metal foil 104. The metal foil 104 may be bonded to the ceramic substrate 101 including the base layer 102, and in the case of using a heat treatment, the metal foil 104 may be performed in a temperature range of 300 ° C. to 900 ° C. When the metal layer and the ceramic substrate are bonded by heat treatment as a paste, heat treatment at a temperature of 1100 ° C. or higher is required, whereas the ceramic circuit board 100 of the present invention exhibits excellent mechanical bonding properties even by heat treatment at low temperatures.

The method of manufacturing the ceramic circuit board of the present invention,

Placing a base layer on a ceramic substrate,

Disposing a bonding layer on the base layer,

The metal foil may be disposed on the bonding layer, and at least one of energy ray irradiation and heat treatment may be performed on the base layer and the bonding layer on the ceramic substrate.

At least one of the base layer and the bonding layer may be formed by a sputtering method, a printing method, or a chemical plating method, among which DC sputtering is most suitable.

According to one embodiment of the invention, the base layer, the bonding layer and the metal foil may be formed on only one side on the ceramic substrate, but is not limited thereto, as shown in FIG. 2, the layer on both sides of the ceramic substrate Can be formed. For example, as shown in FIG. 2, the base layer 202, the bonding layer 303, and the metal foil 204 may be formed on both surfaces of the ceramic substrate 201. Specifically, the base layer 202, the bonding layer 203, and the metal foil 204 are formed on one side of the ceramic substrate 201, and at the same time or after that, the base layer on the other side of the ceramic substrate 201. 202, the bonding layer 203, and the metal foil 204 can be formed.

In FIG. 2, the base layer 202, the bonding layer 203, and the metal foil 204 formed on both surfaces of the ceramic substrate 201 are denoted by the same reference numerals for convenience of description. The constituent materials of each of the base layer 202, the bonding layer 203, and the metal foil 204 to be formed are sufficient as long as they satisfy the scope of the present invention, and are not limited to the exact same.

Physical properties such as TCT characteristics, void incidence, bonding strength, and warpage of the ceramic circuit board manufactured by the above method and the ceramic circuit board manufactured by the conventional method were tested.

The thermal cycle test (TCT) was obtained by examining the number of cycles of delamination by continuously rotating the cycle at a temperature of -55 ° C to 150 ° C. It was confirmed by (scanning acoustic microscopy).

In addition, the void incidence was divided into 30 equal parts on the large ceramic metal bonded substrate, and the void generated area was counted. The bond strength test was performed with a universal testing machine (UTM). The amount of warpage was measured.

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 1-3 and Comparative Example 1: Evaluation of Physical Properties of Metal Bonded Alumina (Al ₂ O ₃ ) Substrate

The ceramic circuit board was manufactured according to the above-described method of manufacturing the ceramic circuit board. As the ceramic substrate, an alumina substrate having a thickness of about 0.38 mm manufactured by the die casting method was used, and Ni _x Cr _{1 -x} (x = 0.8) was used as the base layer. ) / Cu layer was formed by sputtering method, paste printing method and chemical plating method, respectively. The bonding layer was composed of 70 parts by weight of Cu, 10 parts by weight of Sn, 5 parts by weight of P, 5 parts by weight of In and 10 parts by weight of terpineol. The composition was used, and as metal foil, the copper metal foil whose average surface roughness (Rz) is 1.5 micrometers was used (Examples 1-3). In contrast, in Comparative Example 1, a substrate in which a Cu layer was directly bonded to a ceramic substrate without a base layer by using a direct bonding method, which is a conventional method of manufacturing a metal bonded ceramic substrate, was used. In the ceramic circuit boards used in Examples 1 to 3, the thickness of the base layer was 0.15 μm, the thickness of the bonding layer was 50 μm, and the thickness of the copper metal foil was 300 μm.

In each case, the number of TCTs, the incidence of voids, the bond strength, and the amount of warpage of the substrate were measured.

division	Example 1	Example 2	Example 3	Comparative Example 1
Base layer (Ni x Cr 1 -x (x = 0.8) / Cu) formation method	Sputtering	Paste printing method	Chemical plating	No base layer
Bonding layer formation method	Brazing Solder Using Cu / Sn / P / In / terpineol Compositions			Cu direct bonding
TCT Count (times)	1,000	1,000	100 times	60 times
Void Incidence (%)	0.1	0.5	0.1	10
Bond strength (N / mm)	20	20	10	6
Substrate Warpage (mm)	0.5	0.5	0.6	One

* TCT test: -55 ℃ to 150 ℃, 1,000Cycle

* Void occurrence rate: Void occurrence area / total area × 100%

* Board warpage test: Maximum warpage-minimum warpage

As shown in Table 1, compared to the ceramic circuit board (Comparative Example 1) obtained by the conventional method of directly bonding the ceramic substrate and the Cu metal, the base is sputtered, paste printed, chemical plating, etc. on the ceramic substrate. After the layer was formed, the ceramic circuit board of the present invention in which the ceramic substrate was bonded to Cu foil (Examples 1 to 3) exhibited excellent overall physical properties such as TCT, void generation rate, bonding strength, and substrate warping amount.

Therefore, the metal bonded ceramic circuit board of the present invention has excellent mechanical bonding properties and thermal reliability compared to the conventional metal bonded ceramic circuit board, and can be applied in harsh environments such as heat sinks for power semiconductors.

[Description of the code]

100, 200 ceramic circuit board

101, 201 ceramic substrate

102, 202 Base Layer

103, 203 bonding layer

104, 204 metal foil

Claims (18)

1. Ceramic substrates;

   A base layer disposed on the ceramic substrate;

   A bonding layer disposed on the base layer; And

   Ceramic circuit board comprising a metal foil disposed on the bonding layer.
2. The method according to claim 1,

   The ceramic substrate includes at least one selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ) or silicon carbide (SiC), and zirconia (ZrO ₂ ). Ceramic circuit board.
3. The method according to claim 1,

   The base layer is a ceramic circuit board comprising at least one selected from the group consisting of Cu, Ni, Cr, Ti, W, Mn, and Mo.
4. The method according to claim 1,

   The thickness of the base layer is a ceramic circuit board in the range of 0.015 to 0.5㎛.
5. The method according to claim 1,

   The metal foil is a ceramic circuit board containing at least one selected from the group consisting of Cu, Au, Ni and Ag.
6. The method according to claim 1,

   The thickness of the metal foil is a ceramic circuit board in the range of 100 to 600㎛.
7. The method according to claim 1,

   The surface roughness (Rz) of at least one surface of the said metal foil is 3.0 micrometers or less.
8. The method according to claim 1,

   The bonding layer is a ceramic circuit board comprising one or more selected from the group consisting of Cu, Sn, Ni, P, Ag, Zn, Ti, and In.
9. The method according to claim 8,

   The bonding layer is a composition,

   60 to 80 parts by weight of Cu,

   Sn 10 to 30 parts by weight,

   P 3 to 15 parts by weight,

   In 3 to 15 parts by weight, and

   Ceramic circuit board comprising the organic vehicle balance.
10. The method according to claim 9,

    Wherein the organic vehicle comprises at least one organic solvent selected from the group consisting of methanol, ethanol, terpineol and toluene, and optionally an organic binder of at least one of cellulose and acrylic.
11. The method according to claim 1,

    The thickness of the bonding layer is a ceramic circuit board in the range of 100 to 600㎛.
12. An electronic material in which an electronic component is mounted on a ceramic circuit board according to any one of claims 1 to 11.
13. Placing a base layer on a ceramic substrate,

    Disposing a bonding layer on the base layer,

    It includes disposing a metal foil on the bonding layer,

    At least one of energy ray irradiation and heat treatment to the bonding layer, manufacturing method of a ceramic circuit board.
14. The method according to claim 13,

    At least one of the base layer and the bonding layer is formed by a method selected from the group consisting of a sputtering method, a printing method and a chemical plating method.
15. The method according to claim 13,

    At least one of the base layer and the bonding layer is formed by a DC sputtering method.
16. The method according to claim 13,

    The bonding layer,

    60 to 80 parts by weight of Cu,

    Sn 10 to 30 parts by weight,

    P 3 to 15 parts by weight,

    In 3 to 15 parts by weight, and

    A method of manufacturing a ceramic circuit board, which is a composition comprising an organic vehicle balance.
17. The method according to claim 16,

    Wherein said organic vehicle comprises at least one organic solvent selected from the group consisting of methanol, ethanol, terpineol and toluene, and optionally at least one organic binder of cellulose and acrylic.
18. The method according to claim 13,

    The heat treatment is a method of manufacturing a ceramic circuit board is carried out in a temperature range of 300 ℃ to 900 ℃.

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