JPH08222670A - Package for mounting semiconductor devices - Google Patents

Abstract

(57) [Abstract] [Objective] The bottom plate of the package cavity is made of an aluminum nitride sintered body substrate having copper plate layers formed on both sides, so that the heat dissipation from the mounted semiconductor element is high and Provided is a semiconductor device mounting package capable of preventing damage to the device due to thermal shock. In a package in which a bottom plate 1 is bonded to one surface of a frame-shaped circuit board 2 to form a cavity 3, the bottom plate 1 is composed of an aluminum nitride sintered body substrate 5 having copper plate layers 4 formed on both surfaces. It is a package characterized by that.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element mounting package which has a high heating value and is particularly effective when mounting a large semiconductor element. More specifically, by configuring the bottom plate of the package cavity with an aluminum nitride sintered body substrate having copper plate layers formed on both sides, the heat dissipation from the mounted semiconductor element is high and the semiconductor element is damaged by thermal shock. It is a semiconductor device mounting package that can prevent the above.

[0002]

2. Description of the Related Art As the performance and speed of information processing devices have increased, the density and integration of the semiconductor elements forming them have been rapidly increasing. Semiconductor elements such as microprocessors and gate arrays are integrated with 5 to 10 million transistors, and accordingly, the trend toward larger semiconductor elements and higher heat generation is increasing.

Therefore, a semiconductor element mounting package (hereinafter simply referred to as a package) on which the above semiconductor element is mounted is mounted.
As a result, a structure capable of efficiently dissipating the heat generated from the semiconductor element is required.

As a conventional package structure for removing heat generated from the semiconductor element 6, as shown in FIG. 2, a signal including a terminal for wire bonding 8 with the semiconductor element, a ground, and a power source are provided. The bottom plate 1 made of a metal plate of copper, copper alloy, aluminum, aluminum alloy or the like is bonded to one surface of the frame-shaped circuit board 2 on which circuits such as Things are known.

In the above package, the heat generated from the semiconductor element 6 is transferred to and absorbed in the bottom plate 1, and the absorbed heat is released into the atmosphere from the other surface of the bottom plate 1.

In such a package, the mounted semiconductor element 6 has a rubber material capable of absorbing the difference in thermal expansion as the adhesive layer 7 in order to eliminate the difference in coefficient of thermal expansion between the bottom plate 1 and the semiconductor element 6. And a structure in which a metal such as molybdenum having a buffer function is interposed is proposed.

[0007]

However, in the package in which the metal is bonded as the bottom plate as described above, the size of the semiconductor element 6 to be mounted is 5 to 10 mm square, and the heat generation is 3 to 3.
10 W is the practical limit. That is, when the semiconductor element becomes large, for example, when a large semiconductor element 6 having a size of 10 to 20 mm square or more is used, the degree of thermal expansion and contraction due to the difference in thermal expansion coefficient between the bottom plate 1 ′ and the conductor element 6 is large, and the above-mentioned adhesion There is a limit to absorb this depending on the material of the layer 7,
The semiconductor element 6 may be broken or peeled off.

Therefore, in a package in which a large-sized semiconductor element 6 with high heat generation is mounted, it is an important subject to have a particularly excellent heat dissipation property and to match the coefficient of thermal expansion with the semiconductor element 6.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems. As a result, by using an aluminum nitride sintered body substrate (hereinafter referred to as “AlN—Cu substrate”) in which copper plate layers are formed on both surfaces of an aluminum nitride sintered body as a bottom plate constituting the bottom surface of the cavity of the package, It is possible to match the coefficient of thermal expansion with the semiconductor element without impairing the high thermal conductivity of the copper plate, which is a metal plate, due to the excellent thermal conductivity of the sintered body substrate, and the high heat generation and large-sized semiconductor element It was found that a package having a heat sink that is very effective as the above package can be constructed, and the present invention has been completed.

The present invention will be described below in detail with reference to the accompanying drawings, but the present invention is not limited to these accompanying drawings.

FIG. 1 is a sectional view showing a package of a typical embodiment of the present invention.

That is, the package of the present invention is a package in which a bottom plate 1 is bonded to one surface of a frame-shaped circuit board 2 to form a cavity 3, and the bottom plate 1 has copper plate layers 4 on both surfaces.
It is characterized in that it is constituted by the aluminum nitride sintered body substrate 5 on which is formed.

In the present invention, the frame-shaped circuit board 2 constitutes a side wall of the cavity 3 of the package and includes terminals for wire bonding 8 with a semiconductor element.
An input / output signal line to / from the semiconductor element 6, a power supply layer, a ground layer, a power line, a ground line, and the like, on which an arbitrary circuit 15 necessary for the structure of the package is formed, are used without particular limitation.

The material of the frame-shaped circuit board 2 is not particularly limited, and known materials can be used. For example,
Ceramics such as alumina and aluminum nitride, plastics such as epoxy resin, phenol resin, and fluororesin, glass, and composite materials thereof can be used.

With respect to the frame-shaped circuit board 2, a specific embodiment will be described in more detail. When the frame-shaped circuit board is made of ceramics, the frame-shaped circuit board 2 is obtained by sintering the ceramics. Formed by printing a paste containing a metal powder of copper, silver or the like as a conductive substance on the substrate and then curing the paste, and printing the paste using a refractory metal and then sintering to form a metallized layer. The circuit is provided by, and each substrate is joined by a known resin adhesive to form a multilayer, or the ceramics are sintered to obtain a signal layer and a ground layer between a plurality of frame-shaped substrates. The frame-shaped circuit board 2 shown in FIG. 1 is obtained by stacking the power supply layers with a resin adhesive.
1 is formed by printing a paste using a refractory metal on a green sheet of ceramics, stacking these green sheets and performing simultaneous sintering, thereby joining and forming a multilayer structure. A general mode is one in which the frame-shaped circuit board 2 shown is configured. Various pastes above,
Known resin-based adhesives are used without particular limitation,
In addition, various known conditions such as sintering conditions can be adopted without particular limitation.

When the frame-shaped circuit board is made of plastics, it is necessary to perform etching or the like on a copper-clad board having glass epoxy, BT resin, paper phenol, etc. as a base material. A circuit is formed, and if necessary, these substrates are laminated with a resin adhesive,
Examples include a mode in which the frame-shaped circuit board 2 as shown in FIG. 1 is formed.

In the frame-shaped circuit board, the power supply layer and the ground layer are formed in a planar shape in order to realize electrical characteristics of the package, for example, reduction of inductance, and buffering (crosstalk) between signal lines. It is desirable to perform a known circuit design that prevents the above.

Although FIG. 1 shows a mode in which the external connection terminal of the circuit 15 is provided on the side surface of the package, the structure for taking out such a terminal can adopt the structure of other known packages without limitation. it can. For example, a pin grid array structure or a ball grid array structure can also be adopted.

In the package of the present invention, the bottom plate 1 is joined to one surface of the frame-shaped circuit board 2 to form the cavity 3.

The greatest feature of the present invention is that the bottom plate 1 is made of Al.
It is composed of an N-Cu substrate. Such Al
The N-Cu substrate is not particularly limited as long as it is composed of an aluminum nitride sintered body substrate having copper plate layers formed on both surfaces, but in order to form a good heat sink, the aluminum nitride sintered body substrate 5 is Thermal conductivity is 100 W / m
・ K or more, preferably 150 W / m · k or more is recommended. Then, from among these aluminum nitride sintered bodies, an aluminum nitride sintered body having appropriate characteristics may be selected and used in consideration of the heat generation characteristics of the semiconductor element 6 to be mounted.

As the method for producing the aluminum nitride sintered body, a known method of sintering aluminum nitride powder in the presence of a sintering aid is adopted without limitation. As the auxiliary agent, for example, CaO, Y ₂ O ₃ or the like is preferably used. Further, the aluminum nitride powder may contain a coloring compound such as WO ₃ , MoO ₃ , and V ₂ O ₃ . The aluminum nitride sintered body substrate 5 has a high thermal conductivity and a thermal expansion coefficient of a semiconductor element such as a silicon semiconductor element, a gallium-arsenic semiconductor element, an indium-phosphorus semiconductor element (4 × 10 ⁻⁶ / C. to 7 × 10 ⁻⁶ / ° C.), the copper plate layers are formed on both surfaces of the copper plate layer so that the thermal conductivity of the copper plate layer is maintained and the thermal expansion of the copper plate layer is limited to match the semiconductor element. It has become possible to plan.

In the present invention, as the material of the copper plate layer 4, copper alone or a material containing other metal is used without particular limitation as long as the thermal conductivity of copper is not significantly reduced. For example, oxygen-free copper, tough pitch copper, phosphorous deoxidized copper, etc., which are called copper rolled products, or Cu-Fe-Zn which is a wrought copper alloy.
-P-based alloy (C-194), Cu-Zr-based alloy (C-1
51 etc.), Cu-Sn based alloys (EFTEC-3S etc.),
Cu-Ni (white copper) etc. are mentioned. As the copper alloy, one having a composition having a thermal conductivity of about 300 W / m · K or more is suitable.

The copper constituting the copper plate layer is a metal material having a high thermal conductivity, and has a thermal conductivity about twice as high as that of the aluminum nitride sintered body. Therefore, the copper effectively acts in heat dissipation.
It is possible to highly exhibit the heat dissipation of the 1N-Cu substrate. That is, from the viewpoint of heat dissipation as a heat sink, it means that the heat from the semiconductor element 6 is absorbed faster, and the absorbed heat is released to the atmosphere or the refrigerant faster. Depending on the size,
If the size and the calorific value are constant, the heat dissipation of the heat generated from the semiconductor element 6 mainly depends on the heat conductivity of the heat sink and the area of the heat sink surface in contact with the atmosphere or the cooling medium. On the surface of the aluminum nitride sintered body substrate 5 having high heat conductivity, and the copper plate layer 4 having higher heat conductivity.
By forming, a high heat dissipation property is exhibited.

However, according to the experiments by the present inventors, AlN
In the Cu substrate, when the thickness of the copper plate layer 4 is extremely larger than that of the aluminum nitride sintered body substrate 5, nitriding is performed in the process of forming the copper plate layer 4 on the aluminum nitride sintered body substrate 5 and the heat cycle process. Cracks are likely to occur in the aluminum sintered body substrate 5, and the product yield may be reduced. On the contrary, when the thickness of the aluminum nitride sintered body substrate 5 becomes extremely larger than the thickness of the copper plate layer 4, the thermal conductivity of the AlN-Cu substrate tends to decrease.

Therefore, in the present invention, the ratio (TCu / TAlN ratio) of the total thickness (TCu) of the copper plate layer 4 to the thickness (TAlN) of the aluminum nitride sintered body 5 is preferably in the range of 0.1 to 1. is there. More preferably, it is in the range of 0.3 to 0.8. For example, the thickness of the aluminum nitride sintered body 5 (T
When AlN) is 0.6 mm, the total thickness of the copper plate layer 4 is 10
0 μm to 600 μm, preferably 200 μm to 400
μm is preferred.

In the above AlN-Cu substrate, TCu / T
If the AlN ratio exceeds 1, aluminum nitride sintered body 5
The residual stress to the aluminum nitride sintered body 5 may increase, and the stress may lead to the destruction of the aluminum nitride sintered body substrate 5 such as cracks. On the other hand, when the TCu / TAlN ratio is less than 0.2, the heat resistance of the heat sink is aluminum nitride. As a result, the thermal conductivity of the sintered substrate is largely controlled, and as a result, the copper plate layer 4
The thermal resistance in the lateral direction (planar direction) inevitably tends to increase.

From the viewpoint of heat transfer, the thinner the heat sink is, the faster the heat from the semiconductor element 6 can be transferred to the surface of the heat sink. However, the mechanical strength of the heat sink is lowered, and the heat of the package is reduced. Since the reliability may be impaired, the thickness of the AlN-Cu substrate is 0.2.
It is preferable that the thickness is in the range of 10 to 10 mm, preferably 0.5 to 5 mm.

In the AlN-Cu substrate, the difference in thickness of the copper plate layer 4 formed on the front and back of the aluminum nitride sintered body 5 and the difference in area and pattern of the copper plate layer 4 formed are as follows.
The warp of the aluminum nitride sintered body 5 substrate after forming the copper plate is likely to be affected. Therefore, within the above range, it is most preferable to form the copper plate layer 4 symmetrically between the front and back. If necessary, the surface of the copper plate may be plated with Meckel or gold, which is generally known, without any problem.

In the present invention, the above AlN-Cu substrate,
That is, as the aluminum nitride sintered body substrate 5 having the copper plate layers 4 formed on both surfaces thereof, a known bonding method is adopted without particular limitation. For example, a method is generally used in which a copper plate and an aluminum nitride sintered body substrate are pressed against each other at a temperature equal to or higher than the melting point of a brazing material containing an active metal via the brazing material and then cooled. As the active metal, Ti, Zr, Hf, etc. are used, and the addition amount thereof is 0.1 to 20% by weight with respect to the brazing material.
Is appropriate. Moreover, as the brazing material, an Ag—Cu based brazing material is generally suitable.

In the present invention, known techniques are used without limitation for joining the AlN-Cu substrate and the frame-shaped circuit substrate 2 described above. In this case, the type of the adhesive layer 7'and the joining method may be appropriately determined in consideration of the thermal properties such as the thermal expansion coefficient of the frame-shaped circuit board 2, the mechanical strength, the usage environment of the package, and the like.

Further, as in the case where the frame-shaped circuit board 2 uses plastics such as epoxy resin and phenol resin as a base material or uses ceramics such as alumina, thermal expansion with the AlN-Cu substrate is performed. When the rate difference is large, it is preferable to use an adhesive layer 7 ′ used for bonding that has elasticity and strong adhesive strength. In particular,
The elastic modulus at 25 ° C. is 10 kg / mm ² or less, preferably 5 kg / mm ² or less, and the splitting strength between the circuit board and the AlN—Cu substrate is 1 kg / mm ² or more, preferably 2 k.
It is recommended to use g / mm ² or more. As such an adhesive, a fluororubber adhesive containing a copolymer mainly composed of hexafluoropropylene-vinylidene fluoride as a component, a silicone oil containing silane or organopolysiloxane as a main component, a cross-linking agent, and a silane coupling agent. A silicone rubber-based adhesive or the like mixed with an adhesiveness-imparting agent such as As the above-mentioned silicone rubber-based adhesive, a thermosetting type adhesive that produces less reaction by-products is preferably used.

The above-mentioned splitting strength is 20 m in length for a 40 mm square square flat plate sample 0.8 mm thick.
m × width 3 mm × thickness 0.8 mm strip sample 5 mm ×
The strip-shaped sample was adhered with an adhesive so as to be overlapped with each other on a flat surface portion of 3 mm, and the remaining 15 mm × 3 mm portion of the strip-shaped sample which was not adhered was pulled in a 90 ° direction with respect to a plate-shaped sample surface of 40 mm square, and the samples were joined together. The adhesive force was measured by tearing, and then the area of the bonded portion (5 mm × 3 mm in the present invention)
= 0.15 cm ² ) and converted into strength per unit area.

The structure of the package of the present invention is not particularly limited as long as it satisfies the above constitution.

In a preferred embodiment, a radiator having a higher heat radiation function can be added to the back surface of the AlN-Cu substrate forming the bottom plate of the package with high reliability.

That is, as shown in FIG. 3, there is a mode in which the fin-shaped radiator 11 is joined to the bottom plate made of an AlN--Cu substrate. In this case, it is preferable that the joining is mechanically fixed, rather than the joining using a resin adhesive that increases the heat resistance. That is, generally known soldering (for example, Pb-Sn) of the bolt 12 or the like is performed on the metal surface which is the copper plate layer 4.
System, Au—Sn system solder, etc.) or brazing (for example, silver braze shown in JIS Z 3261-1985, particularly BAg-8, BAg-18, BAg-29 is most preferable). Done, then radiator 1
1 can be directly fixed by a nut 13 or the like. Furthermore, the radiator 11 can be directly fixed to the copper plate layer 4 of the aluminum nitride sintered body 5 substrate by spot welding, resistance welding or soldering, and as a result, a resin for fixing the radiator having a large thermal resistance is interposed. Alternatively, it is possible to eliminate the use of a fixing jig or member in a region other than the package for fixing.

It should be noted that bolts and solder materials to be attached to the metal surface,
Fixing material 14 such as brazing material or additional radiator 11
In consideration of the thermal expansion coefficient and mechanical strength of the aluminum nitride sintered body 5 substrate, it is more preferable to select a fixing material having a small difference in thermal expansion coefficient.

Further, the package of the present invention is similar to a generally known resin mold type package, together with the semiconductor element 6 to which the wire bonding 8 is applied and the external connection terminal, a known sealing resin in the cavity. 9
It is also possible to apply molding by.

The semiconductor element 6 is mounted on the package of the present invention by adhering a conventionally used resin, for example, an epoxy resin containing Ag, ceramic powder, glass powder, etc., a polyimide resin, a silicone resin, a fluorine resin or the like. Agent 7
You can fix it directly with.

Further, according to the present invention, the electrical connection from the semiconductor element 6 to the frame-shaped circuit board 2 is performed by the conventional wire bonding method 9 using aluminum wire or Au wire, and the subsequent resin sealing 10. Also, conventional techniques and materials can be used without any problem.

[0040]

As described above, according to the package of the present invention, by using the aluminum nitride sintered body substrate having the copper plate layers 4 formed on both surfaces as the bottom plate, the semiconductor device 6 can be manufactured.
It is possible to form a heat sink having a high thermal expansion coefficient and a thermal expansion coefficient close to that of the semiconductor element 6 of high heat generation and large size.
It is very effective as a package for mounting.

[0041]

EXAMPLES In order to more specifically describe the present invention,
Examples are shown, but the present invention is not limited to these examples.

Example 1 As the bottom plate 1, an aluminum nitride sintered body 5 having a thickness of 0.6
mm, 48 mm square, the thickness of the copper plate layer 4 each 150
A with copper plate layers 4 formed on both sides with a size of 46 mm square in μm A
An 1N-Cu substrate was produced. Aluminum nitride sintered body 5
The copper plate layer 4 and the copper plate layer 4 are bonded to each other by applying an active metal brazing material paste having a composition of Ag 40% by weight, Cu 55% by weight and Ti 5% by weight to a thickness of 30 μm on the front and back surfaces of the aluminum nitride sintered body substrate 5, and then, the copper plate layer 4 And then 2 at 860 ℃ in vacuum.
Heat for 0 minutes. Separately, a frame-shaped circuit board 2 was formed from a glass epoxy copper-clad board. The frame-shaped circuit board 2 had a cavity size of 32 mm square and an outer shape of 50 mm square.

Next, the bottom plate 1 made of the above AlN-Cu substrate and the frame-shaped circuit board 2 are bonded together by using a heat-curable silicone rubber adhesive so as to have a thickness of 100 μm (25 ° C. elastic modulus of 0. 16 kg / mm ² , split strength 5 kg
/ Mm ² ), and a package having the structure of FIG. 1 was produced.

With respect to the package thus obtained, a test silicon chip (semiconductor element 6) having an area shown in Table 1 and a thickness of 0.4 mm was fixed with Ag-epoxy resin. Moreover, the bottom plate 1 is used for the package of the present invention.
A thermal shock test was also performed on a package in which Cu was a simple substance of Cu and aluminum (comparative example). The test conditions are
100 cycles of −65 to 150 ° C. The results are shown in Table 1.
Are also shown.

[0045]

[Table 1]

In the table, the mark ◯ indicates that the semiconductor element 6 was not cracked or cracked, and the mark x indicates that the semiconductor element 6 was cracked or cracked.

From Table 1, in the present invention, the comparative example using copper or aluminum limits the use of a semiconductor element of 10 mm square or less, whereas the larger semiconductor element 6 larger than that has a thermal expansion coefficient. You can see that there is a good match.
Further, no damage such as peeling or cracks was observed on the frame-shaped circuit board 2.

Example 2 Similar to Example 1, a bottom plate 1 made of an AlN—Cu substrate and a frame-shaped circuit board 2 were produced, and a package having the structure shown in FIG. 1 was produced. The copper plate layer 4 (total thickness 0.3 m on both sides)
m, the front and back sides have the same thickness). The thickness of the aluminum nitride sintered body substrate 5 of the bottom plate 1 made of an AlN-Cu substrate is set to 0.
2 mm, 0.4 mm, 0.6 mm, 0.8 mm and 1.
Each package having a size of 0 mm was manufactured.

Next, the test semiconductor element 6 was fixed to each package with Ag-epoxy resin. The chip thickness is 0.4 mm.

Table 2 shows the thermal shock test results of the obtained packages. The test condition is 100 cycles of −65 to 150 ° C.

[0051]

[Table 2]

The mark * in the table indicates that the aluminum nitride sintered body substrate was damaged in the process of producing the AlN-Cu substrate and the package could not be produced. Further, the mark ◯ indicates that the aluminum nitride sintered body forming the aluminum nitride sintered body substrate on which the copper plate layer 4 was formed was not cracked or broken, and the mark x indicates that cracked or broken.

Example 3 A bottom plate 1 made of an AlN—Cu substrate and a frame-shaped circuit board 2 were prepared in the same manner as in Example 2, and a package having the structure shown in FIG. 1 was prepared. In addition, AlN-C with copper plate layers 4 formed on both sides
The bottom plate 1 made of a u substrate has a thickness of 0.6 mm and a total thickness of copper plates of 0.05 mm, 0.1 mm, 0.3 mm, 0.5.
mm and 0.8 mm packages were prepared (formed with the same thickness on the front and back sides).

Next, the test semiconductor element 6 was fixed to each package with Ag-epoxy resin. The chip thickness is 0.4 mm.

Table 3 shows the thermal shock test results of the package. The test condition is 100 cycles of −65 to 150 ° C.

[0056]

[Table 3]

The mark * in the table indicates that the flatness for mounting the semiconductor element 6 could not be obtained because the surface of the bottom plate 1 made of an AlN-Cu substrate had irregularities. In addition, the mark ◯ indicates that the aluminum nitride sintered body 5 of the aluminum nitride sintered body 5 on which the copper plate layer 4 is formed has no cracks or cracks,
The mark x indicates that cracks or cracks have occurred.

Example 4 A bottom plate 1 made of an AlN—Cu substrate and a frame-shaped circuit board 2 were prepared in the same manner as in Example 1, and a package having the structure shown in FIG. 1 was prepared.

Next, an 18 mm square AlN heater chip was bonded to the bottom of the cavity with Ag epoxy resin to obtain a thermal resistance evaluation package. In the evaluation package, the thickness of the aluminum nitride sintered body substrate 5 of the bottom plate 1 made of an AlN-Cu substrate is 0.6 mm and 1.0 mm, and
A copper plate layer 4 having a total thickness of 0.4 mm and 0.6 mm was separately prepared for each (formed with the same thickness on the front and back sides). Table 4 shows the results of evaluating the thermal resistance of the package with the heater power consumption of 5 W and no wind. The numerical value of the thermal resistance is a value (θj-a) obtained by dividing the temperature difference between the temperature on the heater chip and the ambient atmosphere by the power consumption.

[0060]

[Table 4]

From Table 4, the thermal resistance of the package in the windless state is 18.0 to 19.5 ° C./W, and the influence of the thickness of the bottom plate is not significant, but the larger the total thickness of the copper plate layers 4, the greater the total thickness. It can be seen that the thermal resistance tends to decrease.

Example 5 Similar to Example 1, first, the bottom plate 1 made of an AlN--Cu substrate was used.
Was produced. The bottom plate 1 made of an AlN-Cu substrate was manufactured such that the thickness of the aluminum nitride sintered body substrate 5 was 0.6 mm and the total thickness of the copper plate layer 4 was 0.4 mm and 0.6 mm, respectively (with the same thickness on the front and back sides). Formation). afterwards,
A copper screw having a length of 10 mm and an M5 (screw thread distance of 8 mm) was bonded to one copper plate surface of the bottom plate 1 made of an AlN-Cu substrate with Ag low (BAg-29) for fixing the fin.
Separately, a frame-shaped circuit board 2 was produced in the same manner as in Example 1.
Next, the bottom plate 1 made of the above AlN-Cu substrate and the frame-shaped circuit board 2 were joined in the same manner as in Example 1 to produce a package having the structure shown in FIG. Then, 18m as in Example 4
m-square AlN heater chip with Ag on the bottom of the cavity
A package for thermal resistance evaluation was obtained by bonding with an epoxy resin.
The fin is made of metal aluminum and fixed with a nut. It is a thermal resistance evaluation result of the obtained package. The power consumption of the heater is 5 W and the wind speed is 3 m / sec.
The numerical value of the thermal resistance is a value (θj-a) obtained by dividing the temperature difference between the temperature on the heater chip and the ambient atmosphere by the power consumption.

[0063]

[Table 5]

[Brief description of drawings]

FIG. 1 illustrates an exemplary embodiment of a package of the present invention.

FIG. 2 is a schematic cross-sectional view of a conventional general package.

FIG. 3 shows another exemplary embodiment of the package of the present invention.

[Explanation of symbols]

 1 Bottom Plate 2 Circuit Board 3 Cavity 4 Copper Plate Layer 5 Aluminum Nitride Sintered Substrate 6 Semiconductor Element 7 Adhesive Layer 8 Wire Bonding 9 Sealing Resin 10 Radiator 11 Bolts 12 Nuts 13 Soldering Materials, Fixing Materials such as Brazing Materials

Claims (2)

[Claims] 1. A package in which a bottom plate is bonded to one surface of a frame-shaped circuit board to form a cavity, wherein the bottom plate is composed of an aluminum nitride sintered body substrate having copper plate layers formed on both surfaces thereof. Package for mounting semiconductor devices. 2. The ratio (TCu / TAl) of the thickness (TAlN) of the aluminum nitride sintered body to the total thickness (TCu) of the copper plate layer.
The package for mounting a semiconductor element according to claim 1, wherein N) is 0.1 to 1.0.