JP3127895B2 - Carrier for microwave semiconductor element, matching circuit board mounted on carrier, and microwave semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier on which a microwave semiconductor element is mounted, a matching circuit board mounted on the carrier together with the microwave semiconductor element, and a microwave semiconductor element and a matching circuit board mounted on the carrier. To a microwave semiconductor device.

[0002]

2. Description of the Related Art Conventional microwave semiconductor devices include:
This will be described with reference to FIGS. FIG. 10 is a sectional view of a conventional microwave semiconductor device, and FIG. 11 is a plan view of the microwave semiconductor device shown in FIG. 10 before a cap is attached.

As shown in FIGS. 10 and 11, a convex pedestal 112 is formed at the center of the carrier 111, and the microwave semiconductor element 11 is formed on the upper surface of the pedestal 112.
5 is mounted. On both sides of the pedestal 112, a matching circuit board 1 on which a matching circuit for matching input / output is formed.
The matching circuit board 113 and the microwave semiconductor element 115 are electrically connected by bonding wires 116. And the carrier 111
A cap 116 is adhered on the outer peripheral edge of the semiconductor device to seal the microwave semiconductor element 115 and the matching circuit board 113.

In a microwave circuit, when the operating frequency is increased, the inductance component of a bonding wire 114 connecting the microwave semiconductor element 115 and the matching circuit board 113 has an adverse effect on the operation and the high-frequency characteristics are deteriorated. 114 must be as short as possible. Therefore, in order to match the height of the upper surface of the microwave semiconductor element 115 with the height of the matching circuit board 113, the pedestal 112 is provided on the carrier 111 as described above. Usually, the microwave semiconductor element 11
5 is 50 to 100 μm, and the matching circuit board 11
Since the thickness of the base 3 is about 250 μm, the height of the base 112 is 150 μm to 200 μm. In addition, carrier 11
1 is formed of a metal material, and the pedestal 112 is processed by cutting. Therefore, a processing residue 112a having a radius of about 50 μm is generated at the base of the pedestal 112. Bonding wire 1
In order to make the length of the matching circuit board 14 as short as possible,
13 is preferably mounted as close to the pedestal 112 as possible. However, since the unprocessed portion 112a is formed at the base of the pedestal 112 as described above, the matching circuit board 113 is mounted.
If the wire is too close to the pedestal 112, as shown in FIG. 12, the matching circuit board 113 runs over the unprocessed portion 112a, and the length of the bonding wire 114 cannot be made uniform. On the other hand, if the matching circuit substrate 113 is mounted while avoiding the unprocessed portion 112a, the length of the bonding wires 114 will eventually increase, and the high-frequency characteristics will deteriorate.

In order to eliminate the influence of the unprocessed portion, Japanese Unexamined Patent Publication No. Hei 3-185751 discloses a microwave semiconductor device in which the pedestal 122 has an inverted trapezoidal shape as shown in FIG. I have. Thereby, the pedestal 122
The matching circuit board 123 can be brought close to the pedestal 122 without being affected by the unprocessed portion of the base portion of the substrate, and the length of the bonding wire 124 can be shortened.

[0006]

However, if the shape of the pedestal is inverted trapezoidal as disclosed in Japanese Patent Application Laid-Open No. Hei 3-185751, the shape of the pedestal itself and the matching circuit board will not be affected by the remaining processing. When a large gap is formed between the microwave semiconductor device and the pedestal, heat generated from the microwave semiconductor element is not easily transmitted to the carrier. As a result, there is a problem in that the operation reliability and the service life are shortened particularly because the heat generation is large in the high-output microwave semiconductor element.

Further, since the matching circuit board is mounted on the side of the pedestal, there is a limit in shortening the length of the bonding wire. However, in order to further improve the high frequency characteristics, the length of the bonding wire is increased. A structure that can be shortened is also desired.

Accordingly, the present invention provides a carrier for a microwave semiconductor device, which can effectively radiate heat generated from the microwave semiconductor device while having a structure capable of shortening the length of a bonding wire. It is an object to provide a circuit board and a microwave semiconductor device.

[0009]

Means for Solving the Problems] Microwave semiconductor device carrier of the present invention for achieving the above object, a pedestal microwave semiconductor element is mounted is formed on an upper surface, the
Adjacent to the pedestal, the side surface adjacent to the pedestal faces downward for matching the input and output of the microwave semiconductor device.
A carrier for a microwave semiconductor element inclined matching circuit substrate is mounting tower, said pedestal, said matching circuit board
The surface adjacent to the matching circuit board is inclined and formed to have a flared shape when viewed from the side so as to match the side surface of (1).

In the microwave semiconductor device carrier of the present invention configured as described above, the base on which the microwave semiconductor device is mounted has a flared shape, so that the heat from the microwave semiconductor device transfers the carrier. Well diffused inside. The pedestal having such a shape can be easily formed by press working. Therefore, if the pedestal is formed by press working, there is no processing residue at the base of the pedestal. On the other hand, the matching circuit board mounted on this carrier
The side adjacent to the pedestal is inclined downward,
Side of the matching circuit board
Because of the slant , the matching circuit board can be mounted in contact with the pedestal, and the length of the bonding wire connecting the matching circuit board and the microwave semiconductor element is also reduced.

[0011] When the pedestal is formed by cutting, the cutting residue remains at the base of the pedestal. However, by forming a dug portion at the base, the matching circuit board is mounted in contact with the pedestal. It is possible to do. Furthermore, by setting the height of the pedestal to the height obtained by subtracting the thickness of the microwave semiconductor element from the thickness of the matching substrate, the surface of the microwave semiconductor element and the surface of the matching circuit board become the same height, so that the bonding wire Will be shorter.

A matching circuit board according to the present invention is used for matching input and output of a microwave semiconductor element mounted on a pedestal having a side surface inclined to the upper surface of a carrier and formed in a flared shape when viewed from the side. A matching circuit board mounted on the carrier adjacent to the inclined side surface of the pedestal, the surface adjacent to the inclined side surface of the pedestal being inclined so as to coincide with the inclined side surface of the pedestal. It has been formed.

In the matching circuit board of the present invention configured as described above, the pedestal is mounted adjacent to the inclined side surface, and the surface adjacent to the side surface is formed to be inclined so as to match the side surface. Therefore, it is possible to mount on the carrier by contacting the side surface of the pedestal. Generally, the pedestal is formed on the carrier in order to adjust the height of the microwave semiconductor element and the matching circuit board. Therefore, the height of the pedestal is smaller than the thickness of the matching circuit board. Therefore, by mounting the matching circuit board in contact with the pedestal, the pedestal-side end of the upper surface of the matching circuit board protrudes toward the microwave semiconductor element. As a result, the length of the bonding wire connecting them can be reduced.

According to the microwave semiconductor device of the present invention, a microwave semiconductor element, a carrier having a pedestal on which the microwave semiconductor element is mounted, and the input / output of the microwave semiconductor element are matched with each other. In a microwave semiconductor device having a pedestal and a matching circuit board mounted adjacent to a top surface of a carrier, the pedestal has a shape in which a surface adjacent to the matching circuit substrate is inclined and has a flared shape when viewed from a side. The matching circuit board is formed such that a surface adjacent to the inclined surface of the pedestal is formed to be inclined so as to match the inclined surface of the pedestal, and the carrier is brought into contact with the inclined surface of the pedestal. It is characterized by being mounted on.

That is, the combination of the above-described carrier for a microwave semiconductor device of the present invention and a matching circuit board, as described above, is excellent in heat dissipation and requires only a short bonding wire. Wave semiconductor device. In particular, by fixing the carrier and the matching circuit board by soldering, the heat dissipation is further improved. Moreover, even if a gap is formed between the carrier and the matching circuit board, if this gap is filled with solder, the heat dissipation will not be reduced.

[0016]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the microwave semiconductor device according to the embodiment, and FIG. 2 is a plan view of the microwave semiconductor device shown in FIG. 1 before a cap is attached. As shown in FIGS. 1 and 2, a microwave semiconductor device 10 of the present embodiment includes a microwave semiconductor element 15, a carrier 11 on which the microwave semiconductor element 15 is mounted, and a signal input / output of the microwave semiconductor element 15. There are two matching circuit boards 13 on each of which a matching circuit for matching is formed, a cap 16 for sealing the microwave semiconductor element 15 and the matching circuit board 13, and an input terminal 17 and an output terminal 18. .

The carrier 11 is made of a conductive material such as copper.
It is made of tungsten alloy plated with gold,
A pedestal 12 on which the microwave semiconductor element 15 is mounted is formed at the center of the upper surface. As shown in FIG.
The pedestal 12 has a trapezoidal shape, that is, a flared shape when viewed from the side. The inclination angle of the inclined surface 12b connecting the upper surface 12a of the pedestal 12 and the upper surface of the carrier 11 is 4 in this embodiment.
5 °. Therefore, the projected area of the base of the pedestal 12 is larger than the area of the upper surface 12a. Such a base 12 can be easily formed by, for example, press working.

The size of the upper surface 12a of the pedestal 12 on which the microwave semiconductor element 15 is mounted is set at 0 mm around the microwave semiconductor element 15 in consideration of the processing accuracy of the pedestal 12 and the mounting positioning accuracy of the microwave semiconductor element 15. .1 to 0.2
It is formed larger than the size of the microwave semiconductor element 15 with a margin of mm. In the case of the microwave semiconductor element 15 for high output, the size thereof is such that the length LC in the longitudinal direction reaches 4 mm, the width WC reaches 1 mm, and the thickness dC reaches 50 μm. Has a length L of 4.3 mm and a width W of 1.3 mm.

The matching circuit board 13 is mounted on the carrier 11 adjacent to the pedestal 12 on both sides of the pedestal 12. The upper surface of the matching circuit board 13 has an electrode (not shown) for connection to the microwave semiconductor element 15, and this electrode and the electrode (not shown) of the microwave semiconductor element 15 are connected to the bonding wire 14 made of Au. Are electrically connected.
The surface of the matching circuit board 13 adjacent to the pedestal 12 of the carrier 11 is substantially equal to the inclination angle of the inclined surface 12b of the pedestal 11 so as to match the inclined surface 12b of the pedestal 11, as shown in FIG. The matching circuit board 13 is fixed to the carrier 11 by making an inclined surface 13a inclined downward at an angle, that is, 45 °.

Since the thickness of the matching circuit board 13 is about 250 μm, the height d of the pedestal 12 is adjusted to match the height of the electrode of the matching circuit board 13 and the electrode of the microwave semiconductor element 15. The thickness was set to 200 μm, which is a value obtained by subtracting the thickness of the microwave semiconductor element 15 from the thickness of the substrate 13. As described above, the matching circuit board 13 has the inclined surface 13a having the same angle as the inclined angle of the inclined surface 12b of the pedestal 12,
Moreover, since the thickness of the matching circuit board 13 is greater than the height d of the pedestal 12, the end of the upper surface of the matching circuit board 13 on the pedestal 12 side is closer to the microwave semiconductor element 15 from the end of the upper surface 12a of the pedestal 12. It is protruding.

In this embodiment, the amount of protrusion is 50 μm × cot 45 ° = 50 μm because the inclination angle of the inclined surface 13 a of the matching circuit board 13 is 45 ° in the present embodiment. The position can be made closer to the microwave semiconductor element 15. The mounting position of the matching circuit board 13 is set on the inclined surface 13 of the matching circuit board 13.
a can be uniquely determined by contacting a with the inclined surface 12 b of the pedestal 12 of the carrier 11.

Therefore, the length of the bonding wire 14 can be shortened by an amount corresponding to the position of the electrode of the matching circuit board 12 approaching the microwave semiconductor element 15, and
The length of the bonding wire 14 can be made uniform, and the high-frequency characteristics can be further improved. Further, since the matching circuit board 13 has a structure protruding toward the microwave semiconductor element 15, the area of the upper surface of the matching circuit board 13 can be made larger than before, so that the degree of freedom in designing the matching circuit increases. This makes it easier to design a circuit with improved high-frequency characteristics.

On the other hand, heat generated from the microwave semiconductor device 15 by the operation of the microwave semiconductor device 15 is transmitted from the back surface of the microwave semiconductor device 15 to the upper surface 12a of the pedestal 12. This heat is diffused from the upper surface 12a of the pedestal 12 to the inside of the carrier 11, but since the pedestal 12 has a flared shape, the heat is radiated to the carrier 1.
1 and the heat from the microwave semiconductor element 15 can be efficiently radiated. As a result, the reliability and the life of the microwave semiconductor device 15 are not reduced.

Although the above description does not refer to the material of the matching circuit board 13 or the method of fixing the matching circuit board 13, the matching circuit board 13 may be an alumina substrate having a high thermal conductivity, Substrate 13 and carrier 1
By using a solder such as AuSn as an adhesive for fixing to the substrate 1, the heat diffused to the carrier 11 can be further diffused to the matching circuit board 13, and the heat dissipation can be further improved. This does not depend solely on the material of the matching circuit board 13 or the material of the adhesive, but rather on the matching circuit board 13 and the pedestal 1.
2 is also greatly related to the shape. That is, the matching circuit board 13 and the pedestal 12 are mutually inclined.
b are in contact with each other directly or via solder, and a conventional rectangular parallelepiped pedestal 11 as shown in FIG.
This is because the contact area between the pedestal 12 and the matching circuit board 13 is larger than that in the case where the number 2 is provided.

When the matching circuit board 13 and the carrier 11 are fixed by soldering, the matching circuit board 13 and the carrier 1 are fixed.
It is preferable that the entire contact surface of the carrier 11, that is, the bottom surface and the inclined surface 13 a of the matching circuit board 13 be fixed to the carrier 11 and the pedestal 12, since the heat of the carrier 11 is more easily diffused and the heat radiation effect is obtained.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
It is sectional drawing of the microwave semiconductor device of 2nd Embodiment. 6 is a cross-sectional view of the carrier of the microwave semiconductor device shown in FIG. 5, and FIG. 7 is a cross-sectional view near the inclined surface of the matching circuit substrate of the microwave semiconductor device shown in FIG.

When the pedestal 22 of the carrier 21 is formed by cutting instead of press working, as shown in FIG. 6, the base 22 of the pedestal 22 has a cutting residue 22 having a radius of about 50 μm.
c occurs. Therefore, as shown in FIG. 7, after the inclined surface 23a is formed on the matching circuit board 23, a chamfer 23c is applied to a ridge where the inclined surface 23a and the bottom surface 23b intersect. The other configuration is the same as that of the first embodiment, and the description is omitted.

Thus, the inclined surface 2 of the matching circuit board 23
3a can be brought into contact with the inclined surface of the pedestal 22, and the length of the bonding wire 24 for connecting the matching circuit board 23 and the microwave semiconductor element 25 can be shortened. Note that the chamfer 23c is formed on the matching circuit board 23.
Is applied to the chamfered portion 23c and the pedestal 22.
A gap is formed between the substrate and the cutting residue 22c, but since this gap can be filled with the solder used when mounting the matching circuit board 23 on the carrier 21, the heat radiation does not decrease.

(Third Embodiment) FIG. 8 shows a third embodiment of the present invention.
It is sectional drawing of the microwave semiconductor device of 2nd Embodiment. FIG. 9 is a cross-sectional view of the carrier of the microwave semiconductor device shown in FIG.

In this embodiment also, the pedestal 32 of the carrier 31 is formed by cutting, but in this embodiment,
As shown in FIG. 9, a dug portion 32 d in which a portion where cutting residue occurs is dug down in advance is formed at the base of the pedestal 32. Other configurations are the same as those of the first embodiment.
The description is omitted.

Thus, even if the chamfer 23c as shown in FIG.
3 can be brought into contact with the inclined surface of the pedestal 32, and the matching circuit substrate 33 and the microwave semiconductor element 35
Can be reduced in length. By forming the dug portion 32d at the base of the pedestal 32 of the carrier 31, a gap is formed between the dug portion and the 32d matching circuit board 33.
Since this gap can be filled with the solder used when mounting the matching circuit board 33 on the carrier 31, the heat dissipation does not decrease.

As described above, the embodiment of the present invention has been described with an example in which one microwave semiconductor element is mounted on a carrier. However, in practice, a plurality of microwave semiconductor elements are mounted on a carrier. Often do. The present invention is also applicable to a carrier on which a plurality of microwave semiconductor elements are mounted, a matching circuit board mounted on such a carrier, and a microwave semiconductor device including these carriers and the matching circuit board. . Of course, also in this case, the size of the upper surface of the pedestal should be 0.1 to 0.1 mm around the area where the microwave semiconductor element is mounted in consideration of the processing accuracy of the pedestal and the positioning accuracy of the microwave semiconductor element.
It is preferable that the size is such that a margin of 0.2 mm can be obtained.

[0034]

As described above, according to the present invention, since the pedestal of the carrier is formed in a flared shape when viewed from the side, heat from the microwave semiconductor element can be efficiently radiated. Thus, a decrease in the reliability and life of the microwave semiconductor device can be suppressed. Further, if the carrier and the matching circuit board are fixed with solder, the heat from the microwave semiconductor element can be better radiated, and
Even in the case where a gap is formed between the carrier and the matching circuit board, the gap can be filled with solder to prevent a decrease in heat radiation.

Further, the inclination of the side surface of the pedestal and the matching circuit board
By matching the pedestal with the slope of the adjacent side , the matching circuit board is mounted in contact with the pedestal, and as a result, the length of the bonding wire connecting the microwave semiconductor element and the matching circuit board is shortened. As a result, deterioration of the high frequency characteristics can be prevented. In particular, since the pedestal has a flared shape, if the thickness of the matching circuit board is made larger than the height of the pedestal, the pedestal-side end of the upper surface of the matching circuit board protrudes toward the pedestal, so that the bonding wire Can be shortened.

[Brief description of the drawings]

FIG. 1 is a sectional view of a microwave semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a plan view of the microwave semiconductor device shown in FIG. 1 before a cap is attached.

3 is a sectional view of a carrier of the microwave semiconductor device shown in FIG.

FIG. 4 is a cross-sectional view showing the vicinity of an inclined surface of a matching circuit substrate of the microwave semiconductor device shown in FIG. 1;

FIG. 5 is a sectional view of a microwave semiconductor device according to a second embodiment of the present invention.

6 is a sectional view of a carrier of the microwave semiconductor device shown in FIG.

7 is a cross-sectional view of the vicinity of an inclined surface of a matching circuit substrate of the microwave semiconductor device shown in FIG.

FIG. 8 is a sectional view of a microwave semiconductor device according to a third embodiment of the present invention.

9 is a sectional view of a carrier of the microwave semiconductor device shown in FIG.

FIG. 10 is a cross-sectional view of an example of a conventional microwave semiconductor device.

11 is a plan view of the microwave semiconductor device shown in FIG. 11 before a cap is attached.

FIG. 12 is a diagram illustrating a defect of the microwave semiconductor device shown in FIG.

FIG. 13 is a cross-sectional view of another example of a conventional microwave semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Microwave semiconductor device 11, 21, 31 Carrier 12, 22, 32 Pedestal 12a Upper surface 12b Inclined surface 13, 23, 33 Matching circuit board 13a, 23a Inclined surface 14, 24, 34 Bonding wire 15, 25, 35 Microwave semiconductor Element 16 Cap 17 Input terminal 18 Output terminal 22c Cutting remainder 23c Chamfer 32d Dug

Claims (15)

(57) [Claims] 1. A pedestal on which a microwave semiconductor element is mounted is formed on an upper surface, and is adjacent to the pedestal and is provided on the pedestal for matching input and output of the microwave semiconductor element.
A carrier for a microwave semiconductor element matching circuit substrate adjacent the side surface is inclined downwardly is loading tower, the pedestal is consistent with the side of the matching circuit substrate
As described above, a carrier for a microwave semiconductor element , wherein a surface adjacent to the matching circuit substrate is inclined and formed to have a flared shape when viewed from the side. 2. The carrier according to claim 1, wherein the pedestal has a trapezoidal shape when viewed from the side. 3. The carrier for a microwave semiconductor device according to claim 1, wherein the pedestal is formed by press working. 4. The pedestal is formed by cutting,
3. The carrier for a microwave semiconductor device according to claim 1, wherein a dug portion is formed at a base portion of the pedestal. 5. The microwave semiconductor device according to claim 1, wherein the height of the pedestal is a height obtained by subtracting the thickness of the microwave semiconductor device from the thickness of the matching circuit board. For carrier. 6. A sloping side surface of the pedestal for matching input and output of a microwave semiconductor element mounted on a pedestal formed on the upper surface of the carrier and having a flared side shape when viewed from the side. A matching circuit board mounted on the carrier adjacent to the pedestal, wherein a surface adjacent to the inclined side surface of the pedestal is formed to be inclined so as to match the inclined side surface of the pedestal. substrate. 7. The matching circuit board according to claim 6, wherein a ridge at which a surface adjacent to the inclined side surface of the pedestal and a surface mounted on the carrier intersects is chamfered. 8. A microwave semiconductor device, a carrier having a pedestal on which the microwave semiconductor device is mounted, and
In a microwave semiconductor device having a matching circuit board mounted adjacent to the pedestal on an upper surface of the carrier for matching input and output of the microwave semiconductor element, the pedestal is adjacent to the matching circuit board. The inclined surface is formed in a flared shape as viewed from the side, and the matching circuit board is inclined so that a surface adjacent to the inclined surface of the pedestal coincides with the inclined surface of the pedestal. A microwave semiconductor device formed and mounted on the carrier in contact with an inclined surface of the pedestal. 9. The microwave semiconductor device according to claim 8, wherein the matching circuit board is fixed to the carrier by solder. 10. The microwave semiconductor device according to claim 9, wherein the matching circuit board has a surface adjacent to the inclined surface of the pedestal and a surface mounted on the carrier fixed to the carrier. 11. The pedestal is formed by cutting, and the matching circuit board is chamfered at a ridge where a surface adjacent to an inclined surface of the pedestal and a surface mounted on the carrier intersect. 9. The microwave semiconductor device according to claim 8, wherein: 12. The micro circuit according to claim 11, wherein the matching circuit board is fixed to the carrier by solder, and a space between the chamfered portion and a base of the pedestal is filled with the solder. Wave semiconductor device. 13. The microwave semiconductor device according to claim 8, wherein the pedestal is formed by cutting, and a dug portion is formed at a base of the pedestal. 14. The microwave semiconductor device according to claim 13, wherein the matching circuit board is fixed to the carrier by solder, and the dug portion is filled with the solder. 15. The microwave semiconductor device according to claim 8, wherein the height of the pedestal is a height obtained by subtracting the thickness of the microwave semiconductor element from the thickness of the matching circuit board. .