JPH0524943A - Active metallic brazing filler metal and method for joining metallic member and ceramic member by using this active metallic brazing filler metal - Google Patents

Abstract

PURPOSE:To shorten the or the process and to improve joining strength for the brazing filler metal for joining and method for joining a metallic member and a ceramic member as well as to provide a semiconductor device having a smaller size and higher reliability by the application of this method for joining. CONSTITUTION:The brazing filler metal 4 contg. metal Cu, metal Sn and Ag-Cu- Ti alloy as metallic materials contains the metal Cu and the metal Sn respectively at >=5wt.% and <=15wt.% of the weight of the metallic materials and the content of the Ti in the Ag-Cu-Ti alloy is >=1wt.% and <=10wt.% of the alloy weight. This method is constituted of the 1st stage for applying the brazing filler metal 4 on the surface of the metallic member 6 and the 2nd stage for pressing the surface coated with the brazing filler metal of the brazed metallic member and the ceramic member, heating up the members in a vacuum furnace to remove binders and brazing the metallic member and the ceramic member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active metal brazing material and a method for joining a metal member and a ceramic member using the active metal brazing material. More specifically, the manufacturing process is shortened and the bonding strength is improved. The present invention relates to an active metal brazing material that can be used and a method for joining a metal member and a ceramic member using the active metal brazing material.

[0002]

2. Description of the Related Art Conventionally, ceramic members having excellent electric characteristics and heat dissipation have been widely used in the field of manufacturing electric and electronic parts.

Therefore, for example, when a metal member is bonded to a ceramic substrate that constitutes an electric or electronic component, first, a metal paste such as Tungten (W) or molybdenum (Mo) is printed on the metal member bonding site on the ceramic member.・
After coating and then drying, firing is performed to form a metallized layer, and then nickel plating or the like is applied to the surface of the metal member bonding portion of the metallized layer for the purpose of improving wettability with a brazing material, and thereafter, The ceramic member and the metal member are joined by brazing with silver brazing (Ag—Cu alloy).

[0004]

In the above joining method,
After plating the metallized layer formed on the ceramic member with nickel, the ceramic member and the metal member are joined by silver brazing (Ag-Cu alloy).

However, in general, the dimensional accuracy of the metallized layer at the joining position of the metal member on the ceramic member is
It is difficult to say that sufficient strength is obtained after joining because the dimensional accuracy is poorer than that of the metal member, alignment is difficult, and proper positioning is not performed at a predetermined site. Also,
The nickel plating has a disadvantage that the electric insulation between the adjacent metal member and the joint portion is unreliable because the nickel plating protrudes from a predetermined portion or produces a residue.

Therefore, in order to avoid the inconvenience,
Since it is necessary to maintain a sufficient distance between adjacent metal members, it is extremely difficult to miniaturize the electric and electronic components themselves.

Further, since the brazing temperature of silver braze (Ag-Cu alloy) is high, residual stress is generated at the joint. Therefore, between the ceramic member and the metal member,
Increase constraints such as shape and coefficient of thermal expansion.

Therefore, in order to overcome the inconvenience, instead of silver brazing (Ag-Cu alloy), an Ag-Cu-Ti foil having Ti having a large diffusibility to other adjacent components is used and melted and cooled. A method of directly bonding to a ceramic member has been devised.

However, in the above method, although the step of applying nickel plating can be omitted, the above-mentioned Ag-C is used.
Since a high temperature of 780 ° C. to 890 ° C. is required for melting the u-Ti foil, residual stress is generated at the bonding interface between the ceramic member and the metal member due to the difference between the ceramic member and the coefficient of thermal expansion during cooling after melting. However, depending on the thickness of the ceramic member and the metal member, a warp occurs in order to remove a part of the residual stress, and when the residual stress is larger, a crack occurs in the ceramic member, resulting in a joint. This causes a decrease in strength. This warp is caused by the difference between the ceramic member and the coefficient of thermal expansion, and a large residual stress remains even if the warp disappears.
Even if the metal member is pressed and cooled, the joint strength will decrease.
Not resolved.

Further, since Ti diffuses into the metal component and embrittles the material of the metal member, this method has not yet been put to practical use.

Therefore, it is an object of the present invention to provide an active metal brazing agent capable of shortening the manufacturing process and improving the bonding strength in the method of bonding a metal member and a ceramic member.

Another object of the present invention is to provide a ceramic member and a metal member which can be downsized and improved in reliability by applying the active metal brazing material to electric and electronic parts. An object is to provide a joining method.

[0013]

In order to solve the above-mentioned problems, the active metal brazing agent of the present invention comprises metal Cu and metal Sn.
And an Ag-Cu-Ti alloy as a metal material in the active metal brazing material, the metal Cu is in the composition range of 5 wt% or more and 15 wt% or less with respect to the total weight of the metal material, The metal Sn is in a composition range of 5% by weight or more and 15% by weight or less with respect to the total weight of the metal material, and the content of Ti in the Ag-Cu-Ti alloy is the same as that of the Ag-Cu-Ti alloy. It is characterized by being 1% by weight or more and 10% by weight or less with respect to the total weight.

Further, in the joining method of the present invention, on the surface of the metal member to be brought into contact with the ceramic member, a metal material composed of metal Cu powder, metal Sn powder and Ag-Cu-Ti alloy powder, an organic binder, and a plastic An active metal brazing material containing an agent and a solvent, wherein the metal Cu powder is in a composition range of 5% by weight or more and 15% by weight or less based on the total weight of the metal material, and the metal Sn powder is , In the composition range of 5% by weight or more and 15% by weight or less based on the total weight of the metal material, and the Ti in the Ag-Cu-Ti alloy powder is
Content of 1 to 10% by weight based on the total weight of the Ag-Cu-Ti alloy powder is applied, and then the solvent is removed by removing the solvent. A first step of obtaining a metal member with material, and the active metal brazing material coated surface of the metal member with active metal brazing material and the ceramic member are brought into contact with each other, and the temperature is raised in a vacuum furnace to remove the binder, Next, a second step of joining the metal member and the ceramic member by brazing is included.

Furthermore, according to the joining method of the present invention, Ag-Cu-
After applying a paste-like active metal brazing material containing a Ti alloy powder, a metal Cu powder, a metal Sn powder, an acrylic resin, a plasticizer and a solvent, the solvent is removed to remove the active metal brazing material. The first step of obtaining a coated metal member, the active metal brazing material coated surface of the metal member with active metal brazing material and the ceramic member are brought into contact with each other, and the temperature is raised in a vacuum furnace to remove the binder, and A second step of joining the metal member and the ceramic member by brazing.

Here, the ceramic member is not only a member made of only ceramics but also a composite member of ceramics and metal, for example, molybdenum (Mo) or tungsten (W) which is generally used as metallization.
A composite member of glass and glass is also included.

It should be noted that the joining of the member made of both the composite member of ceramics and metal and the member made of only ceramics and the metallic member can be performed by the active metal brazing material and the joining method of the present invention. it can.

[0018]

[Detailed Description of the Structure] In the present invention, after the paste of the active metal brazing material made of powder is applied to the surface of the metal member in contact with the ceramic member, the active metal brazing material paste is heated, melted and cooled. It is brazed to the ceramic member and joined.

Ag-Cu-Ti is used as the active metal brazing material.
An Ag-Cu-Ti alloy having Ti of 1% by weight or more and 10% by weight or less based on the total weight of the alloy is contained. Ti
As shown in FIG. 1, along the grain boundaries, the metal member diffuses to the metal grain boundary, and the ceramic member diffuses to the vicinity of the surface in the ceramic grain boundary to join the metal member and the ceramic member. is doing.

Ti has a high activity as a simple substance, and even TiH easily reacts with carbon, nitrogen and oxygen in a high temperature atmosphere to form a compound, which makes it difficult to react with ceramics, metals and the like. In order to obtain a uniform dispersibility when it is made into a paste, there is concern about surface oxidation when the powder is made fine.
Used as a g-Cu-Ti alloy powder.

In addition, Ti in the active state is carbon (C).
Rich in chemical reactivity with. Therefore, in order to form TiC when carbon remains after firing the paste of the active metal brazing material, an acrylic resin that is thermally decomposed as a monomer is used as the organic binder.

Further, Ti has a high diffusion rate into metal. Therefore, in order to prevent excessive Ti from diffusing into the metal member to embrittle the metal member, the content of Ti in the Ag-Cu-Ti alloy is relative to the total weight of the Ag-Cu-Ti alloy. It was set to 10% by weight or less. Note that Ti
Since the diffusion to the ceramics proceeds at a slow speed, the content of Ti in the Ag-Cu-Ti alloy is Ag-
It was set to 1% by weight or more based on the total weight of the Cu-Ti alloy.

Further, Sn was added to the active metal brazing material in order to avoid embrittlement of the metal member due to excessive diffusion of Ti into the metal member.

Then, metal Cu, metal Sn and Ag-
Brazing of an active metal brazing material containing a Cu-Ti alloy as a metal material will be described. After applying the active metal brazing paste to the surface of the metal member, it is heated to a predetermined temperature to melt the Ag-Cu-Ti alloy. At this time, 7
Before the Ag—Cu component in the Ag—Cu—Ti alloy melts in the temperature range of 00 ° C. to 800 ° C., the eutectic alloy of the metal Cu powder and the metal Sn powder added in advance reaches the melting point and melts. Therefore, the Sn component reacts with the Ti component to prevent excessive diffusion of Ti into the metal member, and Ti diffuses into the ceramic member to obtain a suitable wet state. By using the Ag-Cu-Ti alloy having this suitable wet state and the compounding ratio of the embodiment, the melting point of the active metal brazing material can be lowered, so that the thermal expansion of the metal member and the ceramic member during cooling. The influence due to the difference in the coefficient can be overcome, and since the melting is started in the low temperature region by the addition of the metallic Cu powder component and the Sn component, a warp occurs when the metallic member and the ceramic member are fixed. This contributes to brazing with no voids and few voids, thus improving the joint strength.

Also, to add the metal Sn powder, Ag is added.
The melting temperature of the -Cu-Ti alloy decreases. Therefore, an appropriate melting temperature is set by adding metallic Cu powder. Therefore, the upper limit of the temperature required for melting can be set to the lowest, so that the residual stress of the metal member can be reduced and the bonding strength can be improved.

[0026]

The preferred embodiments of the active metal brazing material and the method for joining a metal member and a ceramic member using the active metal brazing material according to the present invention will be described below in detail with reference to the accompanying drawings. .

In the present embodiment, a method of attaching a metal member to a ceramics substrate in an electric / electronic component will be described.

When attaching the metal member to the ceramic substrate, first, a paste-like active metal brazing material is preferably applied by a screen printing method, a calendar roll method, or the like on the surface where the metal member made of a conductive metal contacts the ceramic substrate. The first step of drying and applying the paste-like active metal brazing material applied to the contact surface where the metal member contacts the ceramic substrate was performed.

The active metal brazing material is Ag-containing 5% by weight of Ti based on the total weight of the Ag-Cu-Ti alloy.
Cu-Ti alloy fine powder, 10 wt% metal Cu fine powder with respect to the total metal weight of the active metal brazing material, and 10 wt% metal Sn with respect to the total metal weight. Of fine powder, an organic binder made of an acrylic resin, and a solvent which can be volatilized by drying to make the above components into a paste. The alloy, the metal material,
The binder was uniformly dispersed in the solvent and used as a paste. In addition, in the Ag-Cu-Ti alloy, the composition of Ag and Cu is Ag 72 wt% and Cu 28 wt% with respect to the total weight of Ag and Cu.
Weight composition or Ag 85% by weight, Cu 15% by weight
Etc. were used.

Cu and S used for the active metal brazing material
The average particle diameters of the n and Ag—Cu—Ti alloy powders were 0.5 to 10 μm, respectively.

Further, the coating thickness of the active metal brazing material of the metal member is set to about 4 μm to 30 μm.

In the first step, the solvent and the volatile components of the organic binder were removed in order to remove an extra load applied to the vacuum furnace when brazing was performed using the vacuum furnace in the second step described later. .

Then, a second step of brazing was performed after the metal member coated with the active metal brazing material was brought into contact with a predetermined joining position of the ceramic substrate to remove the binder, and then brazing.

In the second step, a vacuum furnace is used and the pressure is 10 ^-5 mm.
The temperature was raised to 750 ° C. at a constant heating rate at a vacuum degree of Hg or less. In the process of raising the temperature, first, the binder is removed and the acrylic resin is decomposed as a monomer. Then
Before the brazing material Ag-Cu was melted, the metal Cu powder component and the metal Sn powder component added in advance reached the melting points and melted. Therefore, as shown in FIG. 1, the Sn component 2 reacts with Ti4 to prevent excessive diffusion of Ti4 into the metal member 6, and at the same time, Ti4 diffuses into the ceramic substrate 8 to provide a suitable wet state. Was obtained.

In order to add more metal Sn powder, Ag is added.
The final melting temperature of the -Cu-Ti alloy is reduced to 650
The active metal brazing material started melting in the temperature range near ℃.

In this example, the temperature was raised to 750 ° C. at a constant rate and then cooled to complete brazing. In addition,
The thickness of the brazing material layer after joining was about 2 μm to 15 μm.

If necessary, before performing the second step,
It is also possible to process the metal member at least one or more times after performing the second step.

From the above steps, in the wet state, the difference in the coefficient of thermal expansion between the metal member and the ceramic member during cooling can be overcome, and the addition of the metal Cu powder component and the metal Sn powder component causes melting. Since it is started in a low temperature region, it is possible to perform brazing without a gap when the metal member and the ceramic member are fixed to each other, and further, the final Ag-Cu-Ti alloy constituting the active metal brazing material is formed. Since the typical melting temperature can be lowered, the residual stress of the metal member can be reduced and the joint strength can be improved. Furthermore, it is possible to omit a series of steps for obtaining a nickel plating layer which has been conventionally performed to improve the wettability of ceramics and metals. Therefore, the manufacturing process can be significantly shortened and the cost can be reduced.
It is possible to prevent the electric insulation between the adjacent metal member and its joining portion from being destroyed by the protrusion or residue of nickel plating other than the predetermined portion. Therefore, it is possible to achieve miniaturization of the electric and electronic components themselves that are formed by using the ceramic substrate.

Further, the active metal brazing material 12 according to the present embodiment.
Is, for example, as shown in the vertical cross-sectional view of the electric / electronic component 10 in FIG. 2, joining of a ceramic member 14 made of alumina, mullite, aluminum nitride, glass ceramics, etc. and a metal member such as a lead frame 16, or , Molybdenum (Mo), tungsten (W) metallized vias 18a, and the like, and the metallized portion 18b covering a part or the whole of the ceramic member 14 and the like, and can also be used to obtain electrical conduction. In addition,
Metallization is a composite member of metal (for example, W, Mo) and glass. Further, as the metal member, there are parts such as a pin which is an external terminal, the lead frame, a seal ring and a heat sink.

[0040]

INDUSTRIAL APPLICABILITY As described above, the active metal brazing material and the method for joining a metal member and a ceramic member using the active metal brazing material according to the present invention are suitable for the ceramic member and the metal member by the metal active brazing material. Since the wet state can be obtained, the effect of significantly improving the bonding strength when the metal member and the ceramic member are bonded is obtained.

Further, since a series of steps for obtaining nickel plating, which has been conventionally performed for obtaining a suitable wet state, can be omitted, the manufacturing process can be greatly shortened and the manufacturing cost can be reduced. Produce an effect.

Furthermore, the active metal brazing material and the method for joining a metal member and a ceramic member using the active metal brazing material according to the present invention can be used to reduce the size and improve the reliability, and at the same time, heat dissipation can be achieved. And electrical conductivity can be easily obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the dynamics of Ti and Sn during melting of an active metal brazing material according to the present invention.

FIG. 2 is a longitudinal sectional view showing a preferred embodiment according to the present invention.

[Explanation of symbols]

2 ... Sn component 4 ... Ti 6 ... Metal member 8 ... Ceramics member 10 ... Electrical and electronic parts 12 ... Active metal brazing material 14 ... Ceramics member 16 ... Lead frame 18a ... via part 18b ... Metallization section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Shirasu             57, 1192 Kamiyoshida, Fujiyoshida City, Yamanashi Prefecture (72) Inventor Akihiro Sato             13 3679 Shimoyoshida, Fujiyoshida City, Yamanashi Prefecture

Claims (8)

[Claims] 1. A metal Cu, a metal Sn, and Ag—Cu—T.
In an active metal brazing material containing an i alloy as a metal material, the metal Cu is in a composition range of 5 wt% or more and 15 wt% or less with respect to the total weight of the metal materials, and the metal Sn is the metal The content of Ti in the Ag-Cu-Ti alloy is 5% by weight or more and 15% by weight or less with respect to the total weight of the materials.
1% by weight or more based on the total weight of the g-Cu-Ti alloy 1
An active metal brazing material characterized by being 0% by weight or less. 2. A metal Cu powder, a metal Sn powder and Ag-Cu-on the surface of a metal member to be brought into contact with a ceramic member.
An active metal brazing material containing a metal material composed of Ti alloy powder, an organic binder, a plasticizer, and a solvent, wherein the metal Cu powder is 5 to the total weight of the metal material.
In the composition range of 15 wt% or more and 15 wt% or less, the metal Sn powder is 5 wt% with respect to the total weight of the metal material.
In the composition range of not less than 15 wt% and not more than the Ag-Cu
The content of Ti in the -Ti alloy powder is Ag-Cu-
First step of obtaining a metal member with an active metal brazing material by applying a paste-like active metal brazing material in an amount of 1% by weight or more and 10% by weight or less based on the total weight of the Ti alloy powder, and then removing the solvent And a ceramic member is brought into contact with the active metal brazing material coated surface of the metal member with an active metal brazing material, and the temperature is raised in a vacuum furnace to remove the binder, and then the metal member and the ceramic member are brazed. And a second step of joining by joining. A method of joining a metal member and a ceramic member using an active metal brazing material, comprising: 3. An Ag-Cu-Ti alloy powder and a metallic Cu powder are provided on the surface of the metallic member to be brought into contact with the ceramic member.
A first step of obtaining a metal member with an active metal brazing material by applying a paste-like active metal brazing material containing metal Sn powder, an acrylic resin, a plasticizer, and a solvent, and then removing the solvent; , A ceramic member is brought into contact with the active metal brazing material coated surface of the metal member with an active metal brazing material, and the temperature is raised in a vacuum furnace to remove the binder, and then the metal member and the ceramic member are brazed. A second step of joining by doing so, and a joining method of a metal member and a ceramic member using an active metal brazing filler metal, which comprises: 4. The method for joining a metal member and a ceramic member using an active metal brazing material according to claim 2, wherein the ceramic member is a member made of only ceramics. 5. The method for joining a metal member and a ceramic member using an active metal brazing material according to claim 2, wherein the ceramic member is a composite member of ceramic and metal. . 6. The joining method according to claim 5, wherein the ceramics member is a composite member of metal and glass, wherein the metal member and the ceramics member are made of an active metal brazing material. 7. The method for joining a metal member and a ceramic member using an active metal brazing material according to claim 6, wherein the composite member of metal and glass is metallized. 8. The active metal brazing material according to claim 2 or 3, wherein the ceramic member is a member made of both a composite member of ceramics and metal and a member made only of ceramics. A method for joining a metal member and a ceramic member using the.