JPS637653A - Hermetically sealed metal package for semiconductors - Google Patents

Abstract

PURPOSE:To obtain a package characterized by excellent heat radiating property and glass sealing property and high airtightness, by preparing a metal base with Cu-W alloy, Cu-Mo alloy or Cu-W-Co alloy, and providing a Co-Mo alloy layer on the surface of a glass sealing surface. CONSTITUTION:A metal base is prepared with Cu-W alloy, Cu-Mo alloy or Cu-W-Mo alloy. A Co-Mo alloy layer is provided on the surface of a glass sealing part. This metal package for airtight sealing of a semiconductor is constituted by a metal base material 1, an electric signal input/output lead 2 and a cap sealing part 3. The lead wire 2 is inserted in a through hole 4, which is provided in the metal base 1. For example, the wire 2 is fixed to the metal base 1 with glass 6 as an insulator through a Co-Mo alloy layer 5, which is formed on the inner surface of the through hole, in an airtight manner. A member 7 for sealing a cap (not shown), which is provided on the peripheral part of the metal base 1, is formed with Kovar or stainless steel. The member 7 is brazed to the metal base 1 with BAg 8 and the like.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a hermetically sealed metal package for semiconductors, and more specifically, it is used to mount electronic components such as semiconductor elements or various circuit elements, and has excellent heat dissipation and airtightness. The present invention relates to a hermetically sealed metal package for semiconductors.

After a conventional semiconductor device is given a predetermined function, it is packaged and put into actual use. Puff casing is generally classified into ceramic, metal, glass, plastic packages, etc. based on its structure, but recently, by appropriately combining these packages, a wide variety of structures have been created for semiconductors. It has emerged along with trends such as larger size and higher integration of elements and devices.

From the standpoint of reliability, this package protects the mounted semiconductor elements and other passive elements from the surrounding environment, and sets predetermined internal conditions that allow them to perform their functions normally. plays an extremely important role. Therefore, even if the circuit design and manufacturing process of the chip, etc. are perfect, if the package is incomplete or inappropriate, it will lead to element destruction, quality deterioration, etc., and a failure mode unrelated to the semiconductor device will occur. It turns out.

In other words, puff caging is performed to sufficiently maintain the desired characteristic values of the semiconductor device, to ensure thermal and electrical conduction, insulation distance between electrodes, and to facilitate transportation and handling. In order to increase the integration and performance of semiconductor devices, it plays an important role, especially in ensuring consistency between the devices and external conditions.From this perspective, public packaging and its Improving related technologies is an important issue that must be solved in parallel with improving the performance of semiconductor devices themselves.

By the way, conventional metal packages use Covar/l/ (Fe-Ni-Co alloy), Fe-Ni alloy, Fe, stainless steel alloy, etc. for the metal base, and hermetic sealing is achieved by thermal expansion of the metal base material and glass. There are two main types of methods: the matching method, in which the optimum combination is selected by considering the coefficients, and the thermal expansion coefficients of the metal base material and glass are approximately the same, and the compression method, in which compressive stress is applied to the glass.

In this case, a suitable oxide film is formed on the metal surface, thereby improving wettability to glass during sealing and obtaining good adhesion by diffusion of the oxide.

Problems to be Solved by the Invention However, the metal base materials mentioned above have low thermal conductivity, and the need for high-density packaging, high-speed operation, and high-output operation of semiconductor devices, including high-frequency devices and optical-related devices, is high. The heat dissipation property is not sufficient to cope with the increase in heat generated due to the demand for operability in the environment, resulting in a decrease in performance.

Metal packages have also been developed in which copper, which has good thermal conductivity, is used as a metal base and glass sealing metals such as Fe or Kovar rings or eye lefts are bonded to the glass sealing part by brazing. When subjected to thermal cycles, cracks may appear in the glass due to the difference in thermal expansion coefficient between metals.
The metal and glass may separate, making it impossible to maintain an airtight seal, and even when mounting elements or substrates, thermal stress may cause breakage.

As described above, in order to improve the performance of semiconductor elements/devices in semiconductor device manufacturing technology, it is necessary to improve not only the semiconductor elements/devices themselves but also the packaging methods accordingly.

From the above, in order to improve heat dissipation, Cu-W, which has a higher thermal conductivity than conventional sealing metal materials and is close to copper clay, and a thermal expansion coefficient similar to GaAs and alumina substrates, is used.
It is believed that by selecting alloy, Cu--Mo alloy, or Cu--W-;4o alloy as the metal base material, it is possible to obtain a semiconductor metal package with excellent heat dissipation. However, the above-mentioned Cu-W alloy, C
U-Mo alloy or Cu-W-Mo alloy cannot be used in metal packages that require high airtightness due to poor wettability and compatibility with glass using conventional glass sealing technology, and is generally not suitable for use in metal packages that require high airtightness. Even with the current surface oxidation treatment, it was not possible to obtain a high airtightness sufficient to withstand thermal cycles during manufacturing or use.

Therefore, solving the various drawbacks of hermetically sealed metal packages as described above and developing a package structure that meets recent trends in semiconductor devices will be of great significance for the future development of semiconductor technology. be.

Therefore, an object of the present invention is to provide a hermetically sealed metal package for semiconductors which has excellent heat dissipation properties, excellent glass sealing properties, and therefore has high airtightness.

Means for Solving the Problems In view of the above-mentioned current state of hermetically sealed metal packages for semiconductors, the inventors have conducted various studies and found that the conventional Cu- W alloy, C
U-Mo alloys or Cu-W-Mo alloys are advantageous;
At that time, it is necessary to improve the wettability and compatibility between these alloys and glass, but it has been discovered that this problem can be advantageously solved by applying a specific plating to the glass sealing part of the alloy, and the present invention has been made. completed.

That is, the hermetically sealed metal package for semiconductors of the present invention mounts a semiconductor element or a circuit element and includes a metal base having a lead wire through hole, a lead passed through the through hole and hermetically fixed by glass sealing, a hermetically sealed metal package for a semiconductor, comprising a cap sealed at the peripheral edge of the metal space, wherein the metal base is made of Cu-W alloy, Cu
-! , to alloy or Cu-W-Mo alloy, and is characterized in that a Co-λ1o alloy layer is provided on at least the surface of the glass sealing part.

The metal base material useful in the hermetically sealed metal package of the present invention has a Cu content in the range of 5 to 30% by weight, and is preferably uniformly contained in the alloy.

Further, in the Co-Mo alloy layer applied to at least the surface of the glass sealing part of the metal base, the Mo ratio is 10.
It is preferably within the range of 90% by weight.

The structure of the hermetically sealed metal package for semiconductors of the present invention can be better understood by referring to the attached FIG. That is, the main parts are as shown in Figure 1.
, ``It is composed of a metal base material 1, an electric signal human output lead 2, and a cap seal part 3. Here, lead wire 2
is passed through a through hole 4 provided in the metal base 1, and is hermetically fixed to the metal base 1 by, for example, a Co-Mo alloy layer 5 formed on the inner surface of the through hole 4 with glass 6 as an insulating material. ing. Furthermore, the upper surface layer ff1 of the metal base 1
A cap (not shown) sealing member 7 provided at R is made of Kovar or stainless steel, and is brazed to the metal base 1 with BAg8 or the like.

The cap seal portion 7 and the cap are joined by various conventionally known means, such as electric resistance welding, arc welding, brazing, and soldering, as well as seam welding, which has recently been attracting attention.

A plating layer is used as the alloy layer provided in the glass sealing part and the like. Examples of methods for forming the plating layer include electroplating, electroless plating, and dry plating, all of which give preferable results.

A particular problem with conventional hermetically sealed metal packages for semiconductors is that the thermal conductivity of the material used as the metal base material is too low. In addition, even if Cu-W, Cu-Mo, or Cu-W-Mo is used as a material that can improve this thermal conductivity, it has poor wettability and compatibility with the glass for hermetic sealing, and is not good. An airtight seal could not be obtained.

Therefore, in the present invention, the above-mentioned Cu-Mo, [:u-W, Cu-W, which is advantageous in thermal conductivity as a metal base material]
-Mo alloy was selected, and in order to improve the wettability and compatibility between these and glass, an intervening layer of Co--Mo alloy was provided between them. The wettability and compatibility between this Co-Mo alloy and the metal base material alloy as well as between the Co-Mo alloy and glass are extremely good, and the formation and diffusion of an oxide film that is effective for wettability and compatibility. has an MO content of 10
There is a significant effect in the range of ~90 wt%.

That is, if it is less than 1Qwt%, a sufficient oxide film cannot be obtained, and if it exceeds -90wt%, the oxide film becomes thick and brittle. In addition, the thermal expansion coefficient of the metal base alloy is in the range of 5.5 to 8.0 x 10-6/l. Therefore, by selecting the glass according to the thermal expansion coefficient of the metal base alloy used, matching and compression methods Can be used for either. Therefore, by providing such an intervening layer, it becomes possible to advantageously use each of the above-mentioned alloys with good heat dissipation properties as a metal base material, and as a result, the cranking and peeling of glass that were previously observed, and furthermore, the elements and There is no risk of breakage even if subjected to thermal stress during mounting of the board.

For these reasons, Co-! Advantageously, the content of Mo in the Ao alloy is within the range of 10 to 90 wt%,
Outside this range, the coefficient of thermal expansion, wettability and compatibility with the metal base material or glass will be insufficient, making it impossible to achieve the intended purpose. Further, for the same reason, it is preferable that the content of Cu in the metal base material alloy is also within the range of 5 to 30 wt%.

EXAMPLES Hereinafter, the hermetically sealed metal package for semiconductors of the present invention will be explained in more detail according to examples. However, the scope of the invention is not limited by the following examples.

Embodiment 1 The main parts of a semiconductor hermetically sealed metal package according to the present invention are shown in the attached FIG. 1. A hole 4 is made in the metal base 1 for the lead wire 2 to pass through, the surface of the hole 4 is plated 5 as an alloy layer, and glass is used as the insulation material 6 to airtightly seal it, and after mounting the element, the cap is sealed. Next, a Kovar or stainless steel ring 7 is brazed to the outer peripheral portion 3 of the upper surface of the metal base l with BAg8.

Metal base 1 uses Cu-W alloy, plating 5 uses cobalt sulfate 0.25M/L sodium citrate 0.3M/1
, sodium molybdate 0.2M/A, ammonia 1
．． A Co-Mo plating bath of 8 M/β was prepared and the pH was adjusted to 3.
and pH 11, current density 10A/dm', temperature 60℃
Plating was performed under the following conditions, the lead wire 2 was made of Kovar, the insulating material 6 was made of Kovar sealing glass, and after the glass was sealed, the Kovar ring 7 was silver-soldered to the outer peripheral portion 3 of the upper surface of the metal base 1.

Next, considering the mounting of elements, circuit boards, etc.,
A heat cycle was performed three times in which the sample was moored at ℃ for 5 minutes and then left at room temperature. Conventionally, it was thought that Cu-W alloy could not be hermetically sealed with glass, but even when the helium leak rate was tested with a He leak detector,
It was possible to achieve a high airtight seal with less than cc/sec.

In addition, Cu-W alloy metal base is used as Cu-Mo alloy, Cu
-W-! 1! It was also confirmed that similar results could be obtained by changing to O alloy.

Example 2 Plating was performed as in Example 1, and the outer peripheral part 3 of the upper surface of the metal base was plated as in Example 1.
The stainless steel ring 7 was soldered with silver solder 8, and the lead wire 2 was made of Fe and the insulating material 6 was made of Fe-N+ glass for sealing. After the heat cycle, in the same test as in Example 1, there was a significant difference in hermetic sealability between the plated and non-plated samples, and the plated samples were good.

Effects of the Invention As is clear from the above explanation, according to the present invention, based on the unique feature that the metal base and the lead are hermetically sealed via a specific alloy layer, (1) Cu-W Alloy, C
It is possible to provide a hermetically sealed metal package for semiconductors using u-Mo alloy or Cu-W-Mo alloy as a metal base material; (2) Cu-W alloy, Cu-Mo alloy, Cu-W-Mo
Hermetic sealing for semiconductors has excellent heat dissipation, allowing for higher-density packaging and use with higher output power than when using conventional sealing metals, as the alloy has high thermal conductivity. This has the effect of providing a metal stopper package.

It should be noted that the present invention is not limited to the number of packages shown in the embodiments, and may include a stand or stem for mounting various optical-related elements such as a laser diode, a light-emitting diode, a photodiode, or a high-frequency related element. It can also be advantageously applied to metal bases that require high heat dissipation, such as tables.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway schematic front view for explaining the structure of the main parts of the metal package of the present invention. (Main reference numbers) 1. Metal base, 2. Electrical signal input/output lead, 3. Cap seal section, 4. Through hole, glass sealing section, 5. Plating, 6. Insulating material, 7. Kovar or stainless steel ring, 8. Silver wax

Claims (3)

[Claims] (1) A metal base on which a semiconductor element or a circuit element is mounted and has a lead wire through hole, a lead wire passed through the through hole and hermetically fixed by glass sealing, and sealed at the periphery of the upper surface of the metal base. In the hermetically sealed metal package for semiconductors, the metal base is made of a Cu-W alloy, a Cu-Mo alloy, or a Cu-W-Mo alloy, and the metal base is made of a Cu-W alloy, a Cu-Mo alloy, or a Cu-W-Mo alloy; The above-mentioned hermetically sealed metal package for a semiconductor, characterized in that a Co-Mo alloy layer is provided. (2) Hermetic sealing for semiconductors according to claim 1, wherein the metal-based Cu-W alloy, Cu-Mo alloy, or Cu-W-Mo alloy contains 5 to 30 wt% of Cu. Stop metal package. (3) For a semiconductor according to claim 1 or 2, wherein the Co-Mo alloy layer formed on the surface of the glass sealing part has a Mo content of 10 to 90 wt%. Hermetically sealed metal package.