JPS637655A - Metal package for airtight sealing of semiconductor - 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-Mo alloy, and providing an Fe-Ni alloy layer on the surface of a glass sealing part. CONSTITUTION:A metal base is prepared with Cu-W alloy, Cu-Mo alloy or Cu-W-Mo alloy. An Fe-Ni 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 an Fe-Ni alloy layer 5, which is formed on the inner surface of the through hole 4, 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. Packages, which have emerged in line with trends such as larger size and higher integration of elements and devices, are important in terms of reliability by protecting mounted semiconductor elements and other passive elements from the surrounding environment. It plays an extremely important role in setting the predetermined internal conditions that allow it to perform its functions normally. 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, pubcaging 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 degree of integration and performance of semiconductor devices, packaging and its performance play an important role, especially in ensuring consistency between the device and external conditions. 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 include Kovar (pe-Ni-Co alloy), l'e-Ni alloy, F
e. Stainless alloy, etc. are used, and the airtight sealing is done by selecting the optimal combination by considering the thermal expansion coefficients of the metal base material and glass, and using a matching method in which the thermal expansion coefficients of the metal base material and glass are almost the same. It is broadly divided into compression methods, which apply compressive stress 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.

In addition, metal packages have been developed in which copper, which has good thermal conductivity, is used as a metal base and glass sealing metals such as Fe, Kovar rings, and eyelets are bonded to the glass sealing part by brazing. When it is attached to a device, the glass may crack due to the difference in thermal expansion coefficient between the metals, or the metal and glass may separate, making it impossible to maintain an airtight seal. Also, thermal stress may cause breakage when attaching an element or board. Folds may occur.

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 (close to the value of copper and a coefficient of thermal expansion similar to GaAs and alumina substrates), is used.
It is believed that by selecting a Cu-Mo alloy or a Cu-W-)10 alloy as the metal base material, a metal package for semiconductors with excellent heat dissipation properties can be obtained. 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.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hermetically sealed metal package for semiconductors which has excellent heat dissipation properties, has poor 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 alloy or Cu-W-! JO alloys are advantageous, and it is necessary to improve the wettability and compatibility between these alloys and glass, but this problem can be solved advantageously by applying a specific plating to the glass sealing part of the alloy. They found that this could be solved and completed the present invention.

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 a peripheral edge of the metal base, wherein the metal base is made of Cu-W alloy, Cu
It is made of a Mo alloy or a Cu-W-Mo alloy, and is characterized in that a Fe-Ni alloy layer is provided on the surface of the glass sealing portion.

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 FeN1 alloy layer applied to at least the surface of the glass sealing part of the metal base, the Fe ratio is 5.
The content is preferably within the range of 60% 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, as is clear from FIG. 1, its main parts are comprised of a metal base material 1, electrical signal input/output leads 2, and a cap seal portion 3. Here, the lead wire 2 is passed through a through hole 4 provided in the metal base 1, and the metal It is hermetically fixed to the base 1. Further, a cap (not shown) sealing member 7 provided on the upper peripheral edge of the metal base 1 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 can be joined by various conventionally known means, such as electric resistance welding, arc welding, brazing, and soldering, as well as seam welding, which has been attracting attention recently.

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 vapor phase 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-WSCu-Mo or Cu-W-Mo is used as a material that can improve this thermal conductivity, it has poor wettability and compatibility with the hermetic sealing glass, resulting in poor compatibility. A hermetic seal could not be obtained.

Therefore, in the present invention, Cu-Mo, Cu-WSCu-W-Mo, which is advantageous in terms of thermal conductivity, is used as a metal base material.
The alloys were selected, and an intervening layer of Fe--Ni alloy was provided between them in order to improve the wettability and compatibility between them and the glass. The wettability and compatibility between this Fe-Ni alloy and the metal base material alloy and between the Fe-Ni alloy and glass are extremely good. The formation and diffusion of an oxide film, which is effective for wettability and conformability, cannot be achieved if the Fe content is less than 5%, and if it exceeds 60%, the oxide film becomes thick and brittle. In order to achieve the above-mentioned desired effect, it is advantageous to set the amount in the range of 5 to 60 wt%. Furthermore, the coefficient of thermal expansion of the above metal base alloy is 5.5~
It is in the range of 8.0xlO-'/l, and therefore, by selecting the glass according to the coefficient of thermal expansion of the metal base alloy used, it can be used for both matching and compression methods.

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 cracks and peeling of glass that were previously observed, as well as the There is no risk of breakage even if subjected to thermal stress during mounting of the board.

For these reasons, it is advantageous for the Fe content in the Fe-Nr alloy to be within the range of 5 to 6 Qwt%,
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, glass is used as an insulating material 6 to seal it airtight, and a cap is sealed after mounting the element. Next, a Kovar or stainless steel ring 7 is brazed with BAg 8 to the outer periphery B3 of the upper surface of the metal paste 1.

The metal base 1 is made of Cu-W alloy, the plating 5 is Fe-Ni alloy plating under the condition that the amount of precipitated Fe is 4 Qwt%, the lead wire 2 is Kovar, and the insulating material 6 is made of Kovar.

Glass sealing for Kovar sealing was performed, and the Kovar ring was silver-brazed to the outer peripheral portion 3 of the upper surface of the metal base.

Next, considering the mounting of elements, circuit boards, etc.,
A heat cycle of mooring at 5° C. for 5 minutes and then leaving it at room temperature was performed three times. 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
It was also confirmed that similar results could be obtained even if the -W-Mo alloy was used instead.

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, the lead wire 2 was made of an FeNi alloy, and the insulating material 6 was made of Fe--N1 sealing glass to perform glass 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-M
The use of o-alloys has high thermal conductivity, which allows for higher density packaging and greater output power than when conventional sealing metals are used; for semiconductors with excellent heat dissipation. This has the advantage of providing a hermetically sealed metal 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 the drawing]

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 human 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 Fe-Ni 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) The semiconductor according to claim 1 or 2, wherein the Fe-Ni alloy layer provided on the surface of the glass sealing part has an Fe content of 5 to 60 wt%. Hermetically sealed metal package.