JP3689828B2 - Method and apparatus for manufacturing metal-ceramic composite substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a metal-ceramic composite substrate and an apparatus for manufacturing the same, and in particular, a method for manufacturing a metal-ceramic composite substrate used for a power module semiconductor substrate suitable for automobile parts, train parts and the like, and an apparatus for manufacturing the same. It is about.
[0002]
[Prior art]
Metal-ceramic composites that take advantage of the properties of ceramics such as chemical stability, high melting point, insulation, high hardness, and relatively high thermal conductivity, and high strength, high toughness, easy processability, and conductivity of metals. The member is widely used in automobiles, electronic devices, and the like, and typical examples thereof include a rotor for automobile turbocharging, a metal-ceramic composite substrate for mounting high-power electronic elements, and a package.
[0003]
Adhesion, plating, metallization, thermal spraying, cast-in, brazing, and DBC methods are known as the main manufacturing methods for the metal-ceramic composite member. Most metal-ceramic composite substrates are manufactured by the DBC method using an alumina substrate or brazing using an aluminum nitride substrate.
[0004]
However, in the conventional method, as a method for directly bonding a metal to an alumina substrate, a DBC method for directly bonding a copper plate is known, but a method for directly bonding aluminum has not been known so far.
[0005]
The present applicant previously proposed Japanese Patent Laid-Open No. Hei 8-198629 “Manufacturing apparatus for metal-ceramic composite member” as an apparatus for directly joining aluminum as a metal material to a ceramic member.
[0006]
This apparatus includes a conveying means for continuously supplying a ceramic member, a preheating portion for preheating the conveyed ceramic member, and passing the preheated ceramic member through a molten metal in a crucible to surround the ceramic member. The main part is a joining part that joins metal to at least a part of the surface and a cooling part that gradually cools the joined ceramic member to solidify the metal to form a metal-ceramic composite member.
[0007]
[Problems to be solved by the invention]
Although a large amount of metal-ceramic composite member can be obtained with the above-mentioned apparatus, a considerable effect is obtained. However, when a die is used to solidify the metal into a predetermined shape, there is a problem in that the die is slightly separated. It was.
[0008]
The present invention has the problem that the metal is baked into the die when the ceramic member bonded to the metal in the crucible is slowly cooled, for the purpose of improving the apparatus previously filed by the applicant as described above. It is an object of the present invention to provide a method capable of solving the problem and a manufacturing apparatus thereof.
[0009]
[Means for Solving the Problems]
The inventors of the present invention have intensively studied to solve such a problem. When the aluminum plate forming the circuit or the like is further brought into contact with the ceramic member joined with the molten metal in the crucible and gradually cooled, the bonding strength is improved. It has been found that a high metal-ceramic composite substrate can be produced, and the method and apparatus of the present invention can be provided.
[0010]
That is, in the method for producing a metal-ceramic composite substrate of the present invention, a ceramic member is continuously supplied from the upper side to the lower side, and the metal oxide is removed from the interface between the metal and the ceramic by passing it through the molten metal in the crucible. After the metal melt is adhered to the ceramic surface in a completely removed state and moved in the heating section for a while, the aluminum plate is moved for a while while being in contact with the metal melt to bring the metal melt below the solidification temperature on the left and right cooling body surfaces. Then, the ceramic member and the aluminum plate are joined.
[0011]
The metal is aluminum or an alloy containing aluminum as a main component.
[0012]
The ceramic member is at least one of aluminum, silicon oxide, nitride, and carbide.
[0013]
The metal-ceramic composite substrate manufacturing apparatus of the present invention is a metal-ceramic composite substrate manufacturing apparatus in which metal is bonded to both surfaces of a ceramic member, and conveying means for continuously supplying the ceramic member downward from above. In order to adhere the molten metal to at least a part of the peripheral surface of the ceramic member, the crucible for holding the molten metal that allows the conveyed ceramic member to pass through and the ceramic member to which the molten metal is bonded are maintained at a temperature equal to or higher than the melting point of the metal. A heating part for cooling and a cooling body for cooling these after making an aluminum plate contact the molten metal adhere | attached on both surfaces of the ceramic member are made into a main structural part.
[0014]
The said cooling body hold | maintains this aluminum plate at the temperature below melting | fusing point, when welding the molten metal and the aluminum plate which adhered to the ceramic member.
[0015]
In the apparatus of the present invention, in order to continuously produce the metal-ceramic composite substrate, the molten metal must be continuously supplied and the temperature of the molten metal must be kept constant. In this case, as a method of supplying the molten metal, a method of supplying the molten metal melted in another melting furnace to the crucible in the apparatus of the present invention and heating and holding it at a predetermined joining temperature as required, or a metal raw material Is stably supplied to the crucible in the apparatus of the present invention, melted in the crucible, and heated and held at a constant temperature, but in any case, the crucible for holding the metal in the molten state in any case And a heater.
[0016]
If the ceramic member at room temperature is directly inserted into the molten metal, the ceramic member may break due to thermal shock, and it is necessary to preheat the ceramic member to prevent this. In this case, it is possible to preheat the ceramic member separately by a heating device and supply the preheated member using the conveying means of the device of the present invention, but safety inconvenience when carrying the heated member, Since there is a problem of thermal shock during transportation, in the case of the present invention, the integrated die is used, the residual heat of the heater for heating the molten metal is used, and the heater is provided in the integrated die so that the ceramic member is integrated. Preheat it as it passes through the die.
[0017]
One of the features of the apparatus of the present invention is how to remove the influence of a dirt layer such as a metal oxide from the joining interface between the metal and the ceramic and bring the ceramic member into contact with a clean molten metal. In the present invention, the ceramic member is inserted into the molten metal and formed by the reaction between the metal adhering to the surface of the ceramic member when entering the molten metal, or the reaction between adsorbed oxygen, water vapor and the metal. In order to remove the metal oxide, etc., a method of moving the ceramic member in the molten metal was adopted.
[0018]
There are various means for moving the molten metal. In the present invention, the ceramic member is moved while being inserted into the molten metal along a guide in the integrated die as shown in the embodiments described later.
[0019]
In order to prevent high temperature oxidation of the metal and integrated die used in the present invention, it is necessary to make the inside of the apparatus have a specific atmosphere as required. In the examples described later, the process was performed in a nitrogen gas atmosphere, but the same effect can be obtained by using an inert gas such as argon or hydrogen gas, a reducing gas, or a mixture of these gases.
[0020]
The metal used in the present invention is aluminum or an alloy containing aluminum as a main component, and the ceramic member is an oxide such as aluminum or silicon, a nitride, or a carbide.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0022]
FIG. 1 is a schematic view of the apparatus of the present invention. As shown in FIG. 1, the apparatus of the present invention has a cylindrical integrated die 1 that penetrates a crucible 2 and extends downward from above, and a hole 3 is formed in a portion of the die 1 located in the crucible 2. The molten metal 4 in 2 enters into the die 1. The ceramic members 5 are continuously supplied one by one from the upper entrance of the integrated die 1 into the die 1 by a conveying means using a pinch roller (not shown). The ceramic member 5 is preheated in advance with a preheating heater (not shown) provided on the crucible 2, the metal in the crucible 2 is heated with the molten metal heater 6 to form the molten metal 4, and the ceramic member 5 passes through the molten metal 4. The molten metal 4 is brought into contact with the front and back surfaces of the ceramic member 5, and the ceramic member 5 to which the obtained molten metal is bonded is moved downward while being slowly cooled by the joining heater 7 connected to the bottom of the crucible 2. The aluminum plate 9 is brought into contact with the molten metal. Next, these are passed through a cooling body 8 having a temperature control structure to make it below the solidification temperature of the metal to solidify the molten metal 4 to obtain a desired metal-ceramic composite substrate 10. In addition, a cooling unit (not shown) that gradually cools the ceramic member 5 and a cutting part (not shown) having a cutter that cuts the metal-ceramic composite substrate 10 obtained as a post-process at a connecting portion of the ceramic member 5. )).
[0023]
(Example 1)
[0024]
Using the above apparatus, first, the alumina ceramic member 5 having a size of 36 mm × 112 mm × 0.635 mm was continuously supplied to the preheating portion at the upper part of the crucible 2 using a pinch roller. In this case, since the heat is transmitted to the entire die 1 by the preheating heater in the preheating part, it is preferable to provide a water cooling jacket at the inlet of the die 1 to keep the temperature at 100 ° C. or less.
[0025]
Also, aluminum as a metal is set in the crucible 2, and the ceramic member 5 is inserted from the inlet of the integrated die 1 whose inside diameter is large enough to pass the ceramic member 5, and the tip is on the surface of the cooling body 8. After setting to reach the aluminum plate 9, the crucible 2 is heated in a nitrogen atmosphere to melt the aluminum. The molten aluminum 4 flows out from the joint portion at the bottom of the crucible 2, but the molten metal 4 is prevented from flowing out by making the gap between the die 1 and the aluminum plate 9 0.1 mm or less.
[0026]
After the molten aluminum 4 is heated to 750 ° C., the ceramic member 5 preheated from the inlet side of the die 1 is continuously supplied, and the ceramic member 5 enters the molten metal 4 in order and gets wet with the molten metal 4. It entered into the joint part at the bottom of the crucible 2 and was continuously extruded from an outlet whose internal dimensions were wider than the thickness of the ceramic member 5.
[0027]
Next, the molten aluminum is lowered with both surfaces of the ceramic substrate joined, and an aluminum plate (thickness 0.5 mm) constituting a circuit surface and a heat radiating surface is brought into contact with the molten aluminum at the joint tip, and the cooling body 8 In order to cool the molten aluminum bonded to the ceramic member 5 while passing between the layers to a remelting point of 660 ° C. or lower, the aluminum plate on the front and back surfaces of the ceramic member 5 is completely bonded to obtain an aluminum-ceramic composite substrate. Was made.
[0028]
(Example 2)
[0029]
A plurality of 36 × 26 × 0.635 mm AlN substrates are prepared in advance as the ceramic member 5, and are passed through the molten aluminum 4 by the same means as in the first embodiment to be a metal-ceramic composite member 10 made of an aluminum-AlN member. Got.
[0030]
The metal-ceramic composite substrate 10 obtained by passing through the cooling body 8 was guided to a cutting portion, and the aluminum plate 9 at the joint of the ceramic member 5 was cut with a cutter to obtain a composite substrate having a predetermined shape.
[0031]
【The invention's effect】
By using the above-described method and apparatus of the present invention, it becomes possible to continuously join an aluminum plate to various ceramic members, and various advantages such as the ability to manufacture a predetermined metal-ceramic composite substrate at low cost and in large quantities. is there.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of the main part of an apparatus for producing a metal / ceramic composite substrate of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Integrated die 2 Crucible 3 Hole 4 Molten metal 5 Ceramic member 6 Molten metal heater 7 Joining heater 8 Cooling body 9 Aluminum plate 10 Metal-ceramic composite substrate

Claims (5)

The ceramic member is continuously supplied from above to below, and the molten metal is adhered to the surface of the ceramic in a state where the metal oxide is completely removed from the interface between the metal and the ceramic by passing it through the molten metal in the crucible. After moving for a while in the heating section, the aluminum plate is moved for a while while being in contact with the molten metal, and the molten metal is cooled below the solidification temperature on the left and right cooling body surfaces to join the ceramic member and the aluminum plate. A method for producing a metal-ceramic composite substrate. 2. The method for producing a metal / ceramic composite substrate according to claim 1, wherein the metal is aluminum or an alloy containing aluminum as a main component. 2. The method for producing a metal-ceramic composite substrate according to claim 1, wherein the ceramic member is at least one of aluminum, silicon oxide, nitride, and carbide. In a metal-ceramic composite substrate manufacturing apparatus in which metal is bonded to both surfaces of a ceramic member, a conveying means for continuously supplying the ceramic member from above to below, and a molten metal on at least a part of the peripheral surface of the ceramic member Bonded to both sides of the ceramic member, a crucible for holding the molten metal that allows the conveyed ceramic member to pass through, a heating unit for holding the ceramic member to which the molten metal is bonded, at a temperature above the melting point of the metal, An apparatus for producing a metal / ceramic composite substrate, wherein an aluminum plate is brought into contact with a molten metal, and a cooling body for cooling the aluminum plate is used as a main component. 5. The apparatus for producing a metal / ceramic composite substrate according to claim 4, wherein the cooling body holds the aluminum plate at a temperature equal to or lower than the melting point when welding the molten metal adhered to the ceramic member and the aluminum plate. .

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