JP2687678B2 - Ceramics package for semiconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a semiconductor ceramic package,
The present invention relates to a ceramic package manufacturing technique in which a semiconductor element mounting member made of AlN or SiC and a ceramic frame are joined by interposing an aluminum alloy brazing material.

<Prior Art> The following are known as conventional semiconductor ceramic packages.

For example, as shown in FIG. 3, an alumina package 31
The cavity 32 is formed in the cavity 32, and the silicon chip 33 is die-bonded to the bottom surface of the cavity 32. Further, the chip 33 and the lead are connected by wire bonding and sealed by the lid member 34.

However, this alumina ceramic package
Since 31 is inferior in heat dissipation, it cannot be used as a package for mounting a power IC chip for high output.

As a ceramic package having improved heat dissipation, there is a ceramic package in which an alumina frame 41 and a mounting substrate 43 for an IC chip 42 are separately formed as shown in FIG. The mounting substrate 43 is made of metal, for example, Kovar alloy, dungsten-
It is formed of a copper alloy or the like and has improved heat dissipation from the IC chip 42.

In this case, the joint surface portion of the ceramics (alumina) frame 41 is metalized (Mo-Mn coating) 44, nickel plated 45, and the Ni plated layer 45 and the metal substrate 43 are Ag-C.
These are joined by brazing with the u alloy brazing material 46.

<Problems to be Solved by the Invention> However, in such a conventional ceramic package for a semiconductor, the difference in thermal expansion coefficient between the metal substrate and the ceramic frame is large, and the ceramic frame is formed at the joint portion between them. Deformation such as cracking easily occurs on the body. Especially,
At the time of brazing with an Ag-Cu alloy brazing material, the joining temperature is as high as 820 to 850 ℃, so the thermal deformation of them is remarkable. Further, as a result of using the metal substrate, there is a problem that the weight is large as a whole.

Therefore, it is an object of the present invention to provide a ceramic package for semiconductors which has excellent heat dissipation, does not cause deformation of a mounting member, has high joint strength with a frame, and has achieved weight reduction. .

<Means for Solving the Problems> The present invention is an element mounting member on which a semiconductor element is mounted,
In a ceramic package for a semiconductor having a frame body that is joined to the element mounting member so as to surround the semiconductor element and a lid that seals the semiconductor element, the element mounting member is made of aluminum nitride or silicon carbide. A ceramic package for a semiconductor in which the above-mentioned frame is formed of ceramics respectively, and these are joined together through an aluminum alloy brazing material.

<Operation> The ceramic package for a semiconductor according to the present invention is excellent in heat dissipation because aluminum nitride or silicon carbide is used as the element mounting member. And
Since the joining of the frame and the element mounting member is performed through the brazing material of aluminum alloy, the joining strength of these is sufficiently enhanced, and the strain due to thermal stress is relaxed and absorbed.

Further, since the element mounting member is made of ceramics and the joint portion is made of an aluminum alloy brazing material, it is possible to reduce the weight of the semiconductor ceramic package as a whole.

Table 1 compares the weights of the ceramic plate and the metal plate as the element mounting member.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a ceramic package for semiconductors according to an embodiment of the present invention.

In this figure, 11 is an insulating substrate (SiC substrate) of silicon carbide, which is a semiconductor element mounting member, and a semiconductor element (IC chip) 12 is mounted on this substrate 11.

The end portion of the substrate 11 is joined to a frame body 13 of alumina (Al2O3), and the above-mentioned IC
The tip 12 is surrounded. And this IC chip 12
And the lead provided on the frame body 13 are connected by a bonding wire 14.

Reference numeral 15 denotes a lid body adhered to the upper surface of the frame body 13,
Chip 12 is encapsulated in this package. This lid
15 is formed of a metal plate, for example.

Here, the joint between the substrate 11 and the frame 13 is made of, for example, an aluminum alloy brazing material 16.
As the brazing material 16, for example, an Al-Si, Al-Ge, Al-Cu alloy-based material or the like is used.

Then, in such a ceramic package, the substrate 11 is first bonded to the alumina frame 13.

At this time, the Al-Si brazing filler metal 16 is bonded at a temperature of 580 to 620 ° C, and the Al-Ge brazing filler metal 16 is 440 to 500 ° C.
In the case of the system, it is 560 to 600 ° C. Therefore, since the thermal strain at the time of joining is reduced, the thermal strain applied to the substrate 11 is also reduced.

 Next, the IC chip 12 is mounted on the substrate 11.

Furthermore, after wire bonding, the lid 15 is joined to form a ceramics package in which the IC chip 12 is sealed.

 FIG. 2 shows another embodiment of the present invention.

In this embodiment, an AlN (aluminum nitride) substrate 21 is used to improve heat dissipation. In this case, the AlN substrate 21 has its surface oxidized to form the alumina layer 22. This improves the adhesiveness such as die bonding property of the chip. Further, the use of the AlN substrate 21 also improves high frequency characteristics.

If the frame body 23 is also made of AlN, the thermal expansion coefficients thereof are the same, so that the deformation such as thermal strain of the joint is almost suppressed. An aluminum alloy brazing material 24 is used for the joint. As a brazing material
When using an Al-Cu system, it is necessary to perform surface treatment. Further, when aluminum nitride is used as the frame body, surface oxidation treatment of the joint portion increases the adhesive strength.

 FIG. 5 shows still another embodiment of the present invention.

In this figure, 51 is a silicon carbide substrate, on which an IC chip 52 is mounted via a solder layer 53.
The alumina frame 54 and the substrate 51 are joined together by a laminate of aluminum 57 and aluminum alloy (Al-Si) brazing filler metals 58A and 58B sandwiching the aluminum 57 from above and below.

Further, 55 is a bonding wire, and 56 is a lid.

Thus, the ceramic substrate 51 and the ceramic frame 54 are
It is also possible to join and with a clad brazing material made of a laminate (57, 58A, 58B).

<Effects> As described above, according to the semiconductor ceramic package of the present invention, the heat dissipation is excellent, the bonding strength is high, strain and deformation due to thermal stress and the like do not occur, and moreover, as a whole. Weight reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic structure of a ceramics package for semiconductors according to an embodiment of the present invention, FIG. 2 is a sectional view showing a part of a ceramics package showing another embodiment of the present invention, and FIG. Is a cross-sectional view showing a conventional ceramic package for semiconductors, FIG. 4 is a cross-sectional view showing another conventional ceramic package for semiconductors, and FIG. 5 is a ceramic package according to still another embodiment of the present invention. It is sectional drawing which shows some. 11 ... Silicon carbide substrate (element mounting member), 12 ... IC chip, 13 ... Alumina frame, 15 ... Lid, 16 ... Brazing material.

Claims (1)

(57) [Claims] 1. A semiconductor having an element mounting member on which a semiconductor element is mounted, a frame body which is joined to the element mounting member so as to surround the semiconductor element, and a lid body which seals the semiconductor element. A ceramic package for semiconductors, characterized in that the element mounting member is made of aluminum nitride or silicon carbide, the frame is made of ceramics, and they are joined together through an aluminum alloy brazing material. .