JPH07330475A - Production of joined body consisting of ceramics and metal - Google Patents

Abstract

PURPOSE:To produce joined bodies each consisting of ceramics and a metal with remarkably improved productivity without deteriorating the surface state of the metal or the metal-ceramics joined state. CONSTITUTION:When a metallic circuit and/or a metallic sheet for forming a metallic circuit is laminated on ceramics optionally with a brazing filler metal contg. an active metal in-between and the resultant laminated body is joined by heating, two or more such laminated bodies are superposed while interposing a metallic spacer with a nonoxide layer on the surface and joining is carried out by heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a joined body composed of ceramics and a metal circuit and / or a metal plate for forming a metal circuit.

[0002]

2. Description of the Related Art Conventionally, as a method of joining a metal circuit or a metal plate for forming a metal circuit to a ceramic substrate, a ceramic substrate and a metal circuit and / or a metal for forming a metal circuit with a brazing material containing an active metal interposed therebetween. Active metal method of heat-bonding a laminate with a plate under high vacuum (Japanese Patent Laid-Open No. 60-1776).
34), a direct laminate of an oxide ceramics substrate or an aluminum nitride substrate obtained by oxidizing the surface and a copper circuit and / or a copper plate for forming a copper circuit is formed at a temperature not higher than the melting point of copper.
DBC method in which heat bonding is performed at a eutectic temperature of -O or higher
No. 6-163093) is generally adopted.
Furthermore, Si, Al, Mg, Ca,
After metallizing with a refractory metal such as Mo, Mn, and W through a metal oxide such as Fe, a metal circuit and / or a metal plate for forming a metal circuit is laminated through a brazing material containing no active metal. There is also a metallizing method in which it is heated and joined under high vacuum.

[0003]

However, in the active metal method or the DBC method, the laminated body of the ceramic substrate and the metal circuit and / or the metal plate for forming the metal circuit is heat-bonded as one unit. Productivity was poor. In order to solve this drawback, two or more units may be laminated and heat treated, but in this case, there is a problem that the metals are fused and peeling becomes difficult.

Therefore, a method of heating and joining the units via a spacer has been studied. As a required characteristic of the spacer used for this purpose, a thin ceramic plate is adopted as the spacer from the viewpoints of a small volume, chemical stability, repeated use, no deviation, and easy availability.

However, when ceramics are used as the spacers, when the ceramic substrate joined to the metal circuit and / or the metal plate for forming the metal circuit and / or the ceramic substrate serving as the spacer has a significant warp, it is sandwiched between the spacers. Even if the metal circuit and / or the metal plate for forming a metal circuit and the ceramic substrate are heat-bonded while applying a load, a non-contact portion and / or insufficient adhesion between the metal circuit and / or the metal plate for forming a metal circuit and the ceramic substrate There is a problem that a part is generated and a joint failure occurs.

Therefore, if the spacer is deformable so that it can be easily restored after the treatment, it is deformed in accordance with the warpage of the ceramic substrate during the heat treatment, and the metal circuit and / or the metal plate for forming the metal circuit is made to follow the shape of the ceramic substrate. It should be possible to obtain good bonding. As a result of various studies from this viewpoint, the inventors have found that a metal having a non-oxide layer on the surface is suitable as a spacer, and completed the present invention.

[0007]

That is, according to the present invention, a laminated body in which ceramics and a metal circuit and / or a metal plate for forming a metal circuit are laminated with or without a brazing material containing an active metal is heated. At the time of joining, two or more units each having the above-mentioned laminated body as one unit are laminated via a spacer made of a metal having a non-oxide layer on the surface, and the two are heat-joined, which is characterized by being a ceramic and a metal. Is a method for producing a joined body.

The present invention will be described in more detail below. As for the ceramic substrate, the metal circuit or the metal plate for forming the metal circuit, the brazing material containing the active metal, etc. used in the present invention, the conventional ones are sufficient. The outline of them is as follows.

As the ceramic substrate, an aluminum nitride substrate, an alumina substrate, a mullite substrate, etc. are used.
Among them, an aluminum nitride substrate is used in the active metal and metallizing method, an alumina substrate, a mullite substrate, an aluminum nitride substrate whose surface is oxidized, and the like are used in the DBC method. The thickness of the ceramic substrate is 0.635 mm.
Is general, but is not particularly limited.

The material of the metal circuit and / or the metal plate for forming the metal circuit is copper in the case of the DBC method, and copper, aluminum, tungsten, molybdenum, etc. in the case of the active metal method and the metallizing method. , Copper is common.
Usually, the metal circuit and / or the metal plate for forming the metal circuit is bonded to one surface of the ceramic substrate and the metal heat radiating plate is bonded to the other surface, but there is a structure in which the metal heat radiating plate is not provided. The above-mentioned materials are also used as the material of the metal radiator plate.

The metal component of the brazing filler metal in the active metal method is
It contains silver and copper as main components, and an active metal as a sub-component in order to ensure wettability with the ceramic substrate during melting. Specific examples of the active metal component include titanium, zirconium, hafnium, niobium, tantalum, vanadium and compounds and alloys containing these components. The ratio of these metal components is 69 to 75 parts by weight of silver and 25 to 31 of copper.
3 to 35 parts by weight of the active metal per 100 parts by weight of the total weight part.

The brazing filler metal used in the active metal method or the metallizing method is usually used as a paste, which is prepared by adding an organic solvent and, if necessary, an organic binder to the metal component of the brazing filler metal, and using a roll, kneader or Banbury mixer. It can be prepared by mixing with a universal mixer, a ladle mixer or the like. As the organic solvent, methyl cellosolve, ethyl cellosolve, terpineol, isophorone, toluene, etc., and as the organic binder, methyl cellulose, ethyl cellulose, polymethyl methacrylate, etc. are used.

In the case of the active metal method or metallization method,
The brazing material paste is applied to both the front and back surfaces of the ceramic substrate by screen printing, roll coater method, brush coating, etc., and then the metal circuit and / or metal circuit forming metal plate is formed on one surface of the ceramic substrate and the other surface is formed on the other surface. Metal heat sinks are typically stacked to form one unit of a stack. D
In the case of the BC method, a copper circuit and / or a copper plate for forming a copper circuit and a ceramics substrate are directly laminated without using a brazing paste to form one unit of a laminated body.

According to the present invention, two or more units each having a laminated body formed by the active metal method or the metallization method as one unit or two or more units each having a laminated body formed by the DBC method as one unit are not included. This is to laminate by interposing a spacer made of a metal having an oxide layer on the surface and heat-treating it. The heat treatment condition is 1 in the case of a unit laminate by the active metal method or the metallization method.
At a temperature of 800 to 950 ° C. under high vacuum of 10 ⁻⁵ Torr
0.1 to 1 hour. On the other hand, in the case of a laminated body of units by the DBC method, 10 in a non-oxidizing atmosphere such as N ₂
It is 63-1083 degreeC.

A major feature of the present invention is that a metal having a non-oxide layer on its surface is used as a spacer. Specifically, the surface of a metal such as copper, molybdenum, or tungsten is coated with graphite or BN by a spray method, a chemical vapor deposition method, or the like. In addition, before coating the metal surface, it is preferable to roughen the metal surface from the viewpoint of durability in repeated use. The width of the spacer may be the same as the width of the laminated body. If it is too narrow, the joint may fail due to insufficient load, and if it is too wide, a gap may occur between the laminate itself or between the laminates. Poor bonding or breakage. Further, the thickness is preferably 0.1 to 1 mm from the viewpoints of handleability, durability in repeated use, and volume efficiency. Incidentally, in the present invention, tungsten, tantalum, molybdenum, on the uppermost surface of the plurality of units stacked with a spacer interposed therebetween in order to prevent uneven load,
It is preferable to put a weight such as BN or Si ₃ N ₄ .

[0016]

EXAMPLES Hereinafter, examples and comparative examples will be described in more detail.

Example 1 Aluminum nitride substrate (70 mm × 30 mm × thickness: 0.
635 mm) on both sides, silver powder 72 parts by weight, copper powder 28 parts by weight, zirconium powder 25 parts by weight, terpineol 15 parts by weight, and 1 part by weight of a toluene solution of ethyl cellulose as an organic binder in solid content. A brazing filler metal paste was applied at 7 mg / cm ² (after drying) and dried, and then a copper plate for forming a copper circuit (70 mm × 30 mm × thickness: 0.
25 mm) was laminated on both front and back surfaces.

A copper plate (70 mm × 30 mm × thickness 0.3) coated with carbon spray (product name “DGF” manufactured by Nippon Ship Tool Co., Ltd.) as a spacer between each unit of 25 units of which the obtained laminate is one unit
mm), and 8g / cm ^{2 on the} uppermost surface.
Then, the tungsten weight was placed in a furnace and heated in a high vacuum at 900 ° C. for 30 minutes to manufacture a joined body.

An ultraviolet-curable etching resist is applied to the circuit pattern by screen printing on the copper plate of the obtained joined body, and then an etching treatment is performed using a cupric chloride solution to dissolve and remove unnecessary portions of the copper foil. , Formed a copper circuit. Further, after removing the unnecessary brazing material and the active metal component remaining between the copper circuits and the reaction product of the aluminum nitride substrate by immersing them in a 10% ammonium fluoride solution at 60 ° C. for 10 minutes to remove the etching resist, Was produced.

Regarding the obtained joined body having 25 copper circuits, the surface condition of the copper circuit, the joined condition of the copper circuit, the adhered state of the spacer and the repeated service life, and the deviation of the spacer when laminating the laminated body It measured according to the following. The results are shown in Table 1.

(1) Surface condition of copper circuit: Visual observation was conducted. ⊚: No difference was observed before and after joining, ◯: Adhesion was found on the copper circuit surface, ×: Irregularity was observed on the copper circuit surface. (2) Bonding state of copper circuit: The number of defective copper circuits was measured. (3) Spacer adhesion state: The number of spacers adhered was measured. (4) Repeated use life of spacer: 1 spacer
Visually observe the situation when repeatedly used 00 times, ◎;
There was no abnormality, ◯; abnormal occurrence occurred up to 80 times, and x; abnormal occurrence occurred up to 10 times. (5) Deviation during lamination: The presence or absence of deviation of the laminate when a load is applied was visually observed.

Example 2 A molybdenum plate (70 mm × 30 mm) was used as a spacer.
A joined body having a copper circuit was manufactured in the same manner as in Example 1 except that a carbon spray was used to coat (thickness 0.1 mm).

Example 3 A tungsten plate (70 mm × 30 m) was used as a spacer.
(m × thickness 0.1 mm) A bonded body having a copper circuit was manufactured in the same manner as in Example 1 except that the carbon sprayed coating was used.

Example 4 As a spacer, a copper plate (70 mm × 30 mm × thickness 1
mm) was coated with BN spray (trade name “boron spray” manufactured by Denki Kagaku Kogyo Co., Ltd.), and a bonded body having a copper circuit was manufactured in the same manner as in Example 1 except that the coated product was used.

Example 5 The same as Example 1 except that a laminated body obtained by directly laminating a tough pitch copper circuit punched into the same shape as the circuit pattern on an aluminum nitride substrate was used to carry out a bonding treatment by the DBC method. To produce a joined body having a copper circuit.

Example 6 An aluminum nitride substrate was oxidized to form an Al ₂ O ₃ layer, the surface of which was metallized by the Mo-Mn method, and zirconium powder was removed from the brazing material paste. A joined body having a copper circuit was manufactured in the same manner as in Example 1 except that the laminated body obtained by laminating the copper circuits via the paste was used for the joining treatment.

Comparative Example 1 A bonded body was manufactured in the same manner as in Example 1 except that no spacer was used.

Comparative Example 2 As a spacer, an alumina plate (70 mm × 30 mm ×
A joined body having a copper circuit was produced in the same manner as in Example 1 except that the thickness of 0.635 mm was used.

Comparative Example 3 An aluminum nitride plate (70 mm × 3) was used as a spacer.
A bonded body having a copper circuit was manufactured in the same manner as in Example 1 except that 0 mm × thickness 0.635 mm) was used.

Comparative Example 4 An aluminum nitride plate (70 mm × 3) was used as a spacer.
A bonded body having a copper circuit was manufactured in the same manner as in Example 1 except that a carbon sprayed product having a thickness of 0 mm × a thickness of 0.635 mm) was used.

Comparative Example 5 As a spacer, carbon paper (UCAR Ca
A bonded body having a copper circuit was manufactured in the same manner as in Example 1 except that Rbon Company) was used.

[0032]

[Table 1]

[0033]

According to the present invention, it is possible to manufacture a ceramic-metal bonded body with markedly improved productivity without deteriorating the surface condition of metal and the bonded condition of metal and ceramics.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Miyai 1 Shinkai-cho, Omuta-shi, Fukuoka Prefecture Electric Chemical Industry Co., Ltd. Omuta Factory (72) Inventor Akira Kinoshita 1 Shinkai-cho, Omuta-shi, Fukuoka Electric-type industrial company Omuta Factory

Claims (1)

[Claims] 1. A unit of the above-mentioned laminated body for heating and joining a laminated body in which ceramics and a metal plate for forming a metal circuit and / or a metal circuit are laminated with or without interposing a brazing material containing an active metal. A method for producing a bonded body composed of ceramics and metal, comprising laminating two or more units having a non-oxide layer on the surface thereof with a spacer made of metal, and heat-bonding them.