JP2716959B2 - Aluminum nitride substrate and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an aluminum nitride substrate and a method for manufacturing the same, and more particularly, to metallization and plating for mounting various semiconductor elements thereon. TECHNICAL FIELD The present invention relates to an aluminum nitride substrate provided with a method and a method for efficiently producing the same. 2. Description of the Related Art Conventionally, as a ceramic substrate for mounting a semiconductor element, it is general to use alumina (Al ₂ O ₃ ) having excellent insulation and heat dissipation. The surface of the Al ₂ O ₃ substrate is subjected to a metallizing process and then a plating process, and then, for example, an element is mounted on the plated layer by soldering or the like.
However, when a high-output semiconductor element such as a microwave transistor is mounted on an Al ₂ O ₃ substrate, the heat dissipation of the substrate is insufficient, and the function may be deteriorated due to heat generation of the semiconductor element. Therefore, in place of the Al ₂ O ₃ substrate, an attempt has been made to use a substrate having better heat dissipation properties, such as beryllia (BeO) and aluminum nitride (AlN). [0003] However, BeO is toxic to powder generated as chips when cutting or polishing.
It could not be cut in Japan, and had already been cut to a predetermined shape and size and imported for practical use. Therefore, for example, in the case of a BeO substrate for a microwave transistor, a process of metalizing a BeO plate of about 2 mm × 2 mm one by one, performing plating, and then mounting a predetermined element by, for example, brazing or the like is performed. It is manufactured by going through. [0004] However, such a manufacturing process involves BeO
Since the metallization and plating are performed on each plate, the production cost is increased, and the thickness of the metallized layer and the plating layer formed on each substrate is not uniform. In addition, in the BeO substrate manufactured in this manner, as shown in FIG. 3, the peripheral portions 2a and 3a of the metallized layer 2 and the plated layer 3 formed on the BeO plate 1 are raised. When mounting the element on this, the element is not fixed horizontally, a space is created between the element and the substrate, the heat dissipation is deteriorated, the function of the element is reduced, and in an extreme case, There is a disadvantage that the circuit is destroyed, or the portion 3b protruding from the side surface of the BeO plate 1 comes into contact with another member or the like and peels off, or it cannot be incorporated into the circuit due to dimensional defects. This is a cause of significantly lowering the properties. [0005] As described above, the conventional B
eO substrates have poor manufacturing efficiency, low product homogeneity,
Further, there is a problem that it is difficult to maintain the function of the element in a stable state. The present invention solves the above-mentioned conventional problems and does not cause any swelling at the peripheral portions of the metallized layer and the plating layer formed on the surface, so that the element can be stably mounted. It is an object of the present invention to provide a substrate that can be stably incorporated into a circuit without causing peeling of a plating layer or the like and dimensional defects, and a method of manufacturing such a substrate with high efficiency. Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, first, instead of BeO as a substrate material, cutting, cutting, etc., which have good heat dissipation properties, are used. Aluminum nitride (AlN), which can be processed as described above, is employed. In addition, when manufacturing a substrate, a large-area AlN plate is subjected to metallizing treatment and plating treatment.
The inventors have found that if the N plate is cut into a predetermined size and shape, it is possible to efficiently mass-produce an AlN substrate having a horizontal metallized layer and a plated layer formed on the surface, thereby completing the present invention. . That is, the aluminum nitride substrate of the present invention has an aluminum nitride plate having a heat conductivity of 50 W / m · k or more and excellent heat dissipation and a metallized layer and a plating layer laminated on a surface of the aluminum nitride plate in this order. A metallized layer having a high melting point metal component and a plated layer are formed on the entire surface of the aluminum nitride plate, and the metallized layer is exposed on the side surface of the aluminum nitride substrate. The side surface is on the same plane as the aluminum nitride plate side surface. In particular, it is preferable that the metallized layer and the plated layer are parallel to the surface of the aluminum nitride plate. Specifically, the flatness of a portion used as a product after cutting out of the metallized and plated surfaces is 20 μm.
The thickness may be set to be equal to or less than 10 μm. Further, it is preferable that the metallized layer is exposed on all side surfaces of the aluminum nitride substrate. The manufacturing method is characterized in that a metallizing treatment and a plating treatment are sequentially performed on a surface of the aluminum nitride plate using a paste having a high melting point metal component to form an aluminum nitride substrate, and then the aluminum nitride substrate is cut. In particular, it is preferable to perform metallization and plating on the entire surface of the aluminum nitride plate, and after sequentially performing metallization and plating to form an aluminum nitride substrate, before cutting the aluminum nitride substrate, the surface of the peripheral portion of the aluminum nitride substrate is cut. Flatness is 20μ
It is preferable to excise a region exceeding m. Further, the aluminum nitride substrate can be cut into a plurality of aluminum nitride substrates. [0010] In order to obtain such a substrate, the flatness of a portion used as a product after cutting, of the surface subjected to the metallizing treatment and the plating treatment, may be set to 20 µm or less, and particularly to 10 µm or less. preferable. In the present invention, the size of the AlN substrate after cutting is not particularly limited, but a small-sized substrate is particularly effective. Specifically, the surface shape is 20 mm x 20 m
m, preferably within 10 mm x 10 mm, more preferably within 3 mm x 3 mm. This AlN
The material of the metallized layer and the plating layer formed on the plate is, for example, molybdenum (Mo),
Examples of the paste include a paste having a high melting point metal component such as tungsten (W) and a high melting point metal component, or a paste obtained by adding an additive to the paste. Nickel (Ni), gold (Au) is used as a plating layer. Can be used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A method for manufacturing an N substrate will be described below. First, a large-sized AlN plate 11 as shown in FIG. 1 is prepared, and a metallizing treatment is applied to the entire surface of the AlN plate 11 to form a metallized layer 12 having a high melting point metal component. Further, a plating process is performed to form a plating layer 13. Next, the peripheral portion of the AlN plate 11 thus obtained, that is, the region A where the metallized layer 12 and the plated layer 13 are not horizontal is cut. Thereafter, the large-sized AlN plate 11 on which the metallized layer 12 and the plated layer 13 are laminated is cut into a desired size as shown in FIG.
An 1N substrate 14 is obtained. The thus obtained AlN substrate 14 of the present invention has a metallized layer 12 and a plated layer 13 formed on the entire surface of the AlN plate 11 so that both surfaces are Al.
The surfaces parallel to the surface of the N plate 11 and the side surfaces of these layers 12 and 13 are located in the same plane as the side surface of the AlN plate 11. Since the surface of the plating layer 13 of the AlN substrate 14 is horizontal, it is possible to stably mount elements without deteriorating heat dissipation, and the function is not reduced.
In addition, since there is no protrusion from the side surface of the substrate, it is possible to stably incorporate the circuit. EXAMPLE An AlN plate having a length of 50 mm, a width of 50 mm and a thickness of 0.5 mm was prepared. After a metallized layer having a thickness of 15 μm was formed on the entire surface of the AlN plate using a Mo—TiN paste, a 5 μm thick plating layer made of Ni was further formed thereon. Aln later this AlN
A 5 mm wide area along the periphery of the plate was cut. Then, the AlN plate was cut to obtain 400 AlN substrates having a length of 2 mm and a width of 2 mm. No flatness exceeded 20 μm. When a microwave transistor is mounted on the plating layer of the AlN substrate obtained as described above, the function of the element is deteriorated due to poor heat radiation, the element cannot be incorporated into the circuit due to defective dimensions, and the element is dropped. Nothing was there. [0017] For comparison, after performing one by one metalized and plating treatment as described above the Al ₂ O ₃ and BeO each 100 substrate of the AlN substrate and the same dimensions, equipped with microwave transistors A
The device using the l ₂ O ₃ substrate could not satisfy the function required as an element, and the device using the BeO substrate caused a decrease in device performance due to a decrease in heat dissipation of ten of them. As is clear from the above description, in the aluminum nitride substrate of the present invention, the surfaces of the metallized layer and the plating layer are parallel to the surface of the aluminum nitride plate. Since it can be mounted in a state, the heat dissipation of the substrate is not impaired, and the peripheral edge of the plating layer does not protrude from the aluminum nitride plate side surface,
It is possible to incorporate the circuit in a stable state. Further, according to the manufacturing method of the present invention, it is not necessary to perform the metallizing process and the plating process for each substrate as in the conventional case, and a large amount of a uniform aluminum nitride substrate is manufactured by one metallizing process and the plating process. This contributes to a reduction in manufacturing cost. Therefore, its industrial value is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a manufacturing process of an aluminum nitride substrate of the present invention. FIG. 2 is a perspective view showing a manufacturing process of an aluminum nitride substrate of the present invention. Cross-sectional view showing structure [Description of References] 11 ... AlN plate 12 ... metallized layer 13 ... plated layer 14 ... AlN substrate

Claims (1)

(57) [Claims] An aluminum nitride substrate having a metallized layer and a plating layer laminated on a surface of an aluminum nitride plate in this order, wherein a metallized layer and a plating layer having a high melting point metal component are formed on the entire surface of the aluminum nitride plate, and An aluminum nitride substrate, wherein the metallized layer is exposed on the side surface of the aluminum substrate, and the metallized layer side surface and the plating layer side surface are flush with the aluminum nitride plate side surface. 2. 2. The aluminum nitride substrate according to claim 1, wherein the high melting point metal component is molybdenum and / or tungsten. 3. 3. The aluminum nitride substrate according to claim 1, wherein the metallized layer and the plating layer are parallel to the surface of the aluminum nitride plate. 4. 4. The metallized layer is exposed on all side surfaces of the aluminum nitride substrate.
Item 6. The aluminum nitride substrate according to item 1. 5. The flatness of the aluminum nitride substrate surface is 20 μm
The aluminum nitride substrate according to any one of claims 1 to 4, wherein: 6. The aluminum nitride substrate according to any one of claims 1 to 5, wherein the plating layer is nickel and / or gold. 7. A method for manufacturing an aluminum nitride substrate, comprising: performing a metallizing process and a plating process on a surface of an aluminum nitride plate using a paste having a high melting point metal component to form an aluminum nitride substrate; and cutting the aluminum nitride substrate. 8. The method for manufacturing an aluminum nitride substrate according to claim 7, wherein the high melting point metal component is molybdenum and / or tungsten. 9. 9. The method for manufacturing an aluminum nitride substrate according to claim 7, wherein a metallizing process and a plating process are performed on the entire surface of the aluminum nitride plate. 10. 10. After the metallization process and the plating process are sequentially performed to form an aluminum nitride substrate, before cutting the aluminum nitride substrate, an area where the flatness of the surface of the peripheral portion of the aluminum nitride substrate exceeds 20 μm is cut off. 2. The method for producing an aluminum nitride substrate according to claim 1. 11. The method for manufacturing an aluminum nitride substrate according to any one of claims 7 to 10, wherein the aluminum nitride substrate is cut into a plurality of aluminum nitride substrates. 12. The method for manufacturing an aluminum nitride substrate according to any one of claims 7 to 11, wherein the plating layer is nickel and / or gold.