JPS637652A - 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 Ni-P alloy plated 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 Ni-P alloy plated layer is provided on a glass sealing part. This metal package for airtight sealing of a semiconductor is constituted by the metal base 1, an electric signal input/output lead 2, and a cap sealing part 3. The lead 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 Ni-P plated 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. Regarding metal packages for semiconductors.

After a conventional semiconductor device is given a predetermined function, it is packaged and put into actual use. The types of pub caging are generally classified into ceramic, metal, glass, plastic snack packaging, etc. based on their structure, but recently, by appropriately combining these, a wider variety of structures have been created. It has emerged with the trend of larger and more highly integrated semiconductor 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. It plays an important role in achieving higher integration and higher performance of semiconductor devices, especially ensuring compatibility between the device and external conditions.From this perspective, 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 include Kovar (Fe-Ni-Co alloy), Fe-Ni alloy, Fe
, stainless steel alloy, etc. are used, and the optimal combination is selected in consideration of the thermal expansion coefficients of the metal base material and glass, and the matching method is used to ensure that the thermal expansion coefficients of the metal base material and glass are almost the same. It is broadly divided into compression methods that apply compressive stress to the glass.

In this case, a suitable oxide film is formed on the metal surface, and during sealing, good adhesion is achieved by improving the wettability to glass and by diffusing 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. Since the heat dissipation property is not sufficient to cope with the increase in heat generation caused by the demand for operability in the field, performance deteriorates. 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 or Kovar rings are bonded to the glass sealing part by brazing. When mounting, the glass may crack due to the difference in coefficient of thermal expansion between metals, or the metal and glass may separate, making it impossible to maintain an airtight seal. Even when mounting an element or board, it may break due to thermal stress. 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 is used because its thermal conductivity is higher than conventional sealing metal materials and is close to the value of copper, and its thermal expansion coefficient is close to that of GaAs and alumina substrates. alloy, Cu Mo alloy or C'u-W
It is believed that by using the -Mo alloy as the metal base material, a metal package for semiconductors with excellent heat dissipation properties can be obtained. However, Cu-W alloy, Cu-Mo alloy, or Cu-W-Mo alloy as described above has poor wettability and compatibility with glass using conventional glass sealing techniques, so it is not suitable for metal packages that require high airtightness. could not be used, and even if surface oxidation treatment, which is commonly performed, was performed, high airtightness that could sufficiently withstand thermal cycles could not be obtained.

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 present inventors have developed the conventional Cu-W alloy, Cu-M
O alloys or Cu-W-Mo alloys are advantageous for ensuring heat dissipation properties of metal packages. Therefore, it is necessary to improve the wettability and compatibility of these alloys with glass, and this problem can be solved. It was discovered that the problem could be advantageously solved by applying a specific plating to the glass sealing part of the alloy, and the present invention was 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 a peripheral edge of the metal base, wherein the metal base is made of a Cu-W alloy (:u
-Mo alloy or Cu-W-Mo alloy, and is characterized by having a NiP alloy plating layer 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 N1-P alloy plating layer applied to at least the surface of the glass sealing part of the metal base, the ratio of P is preferably within the range of 3 to 12% 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 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
It passes through a through hole 4 provided in the metal base 1 and is hermetically fixed to the metal base 1 with glass 6 as an insulating material, for example, via an N1-P plating layer 5 formed on the inner surface of the through hole 4. . Furthermore, 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 G8 or the like to B. ing.

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.

Examples of methods for forming the plating layer provided on the glass sealing portion include electroplating, electroless plating, and vapor phase plating, all of which give preferable results.

Rozuki: A particular problem with conventional hermetically sealed metal packages for semiconductors was that the thermal conductivity of the material used as the metal base material was too low. In addition, materials that can improve this thermal conductivity include Cu-W and Cu-Mo.
Alternatively, even if Cu-W-Mo or the like is employed, it has poor wettability and compatibility with the glass for hermetic sealing, and good hermetic sealing cannot be obtained.

Therefore, in the present invention, the above-mentioned Cu-Mo, Cu-W, and Cu-W, which are advantageous in terms of thermal conductivity, are used as metal base materials.
-Mo alloy was selected, and an intervening layer of Ni-P alloy was provided between them in order to improve the wettability and compatibility between these and the glass. The wettability and compatibility between this N1-P alloy and the metal base material alloy as well as between the N1-P alloy and glass are extremely good, and the formation and diffusion of an oxide film that is effective for wettability and compatibility. has a P content of 3 to 12 wt%
It has a significant effect within the range of .

In addition, the coefficient of thermal expansion of the above metal base alloy is 5.5 to 8.0X.
IO-6/l: and by selecting the glass, it is possible to advantageously use each of the above-mentioned alloys with good thermal properties as a metal base material, and as a result, cracks in glass that were previously observed, There is no risk of breakage even if it is peeled off or subjected to thermal stress during mounting of elements or substrates.

For this reason, the P content in the NiP alloy is 3~
It is advantageous to keep the content within the range of 12 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. Moreover, 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 30Wi96.

EXAMPLES Hereinafter, the hermetically sealed metal package for semiconductors of the present invention will be described in more detail according to Examples (manufacturing examples). but,
The scope of the invention is not equally 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 formed in the metal base 1 for the lead wire 2 to pass through, the surface of the hole 4 is plated 5, glass is used as the insulating material 6, and the airtight seal is made. A cover 7 or a stainless steel ring 7 is attached to the outer periphery 3.
Braze with g8. The metal base 1 is made of Cu-W alloy, the plated part 5 is plated with N1-P alloy under the condition that the amount of precipitated P is 8 wt%, the lead wire 2 is made of Kovar, and the insulating material 6 is made of Kovar sealing glass. The Kovar ring was silver-soldered to the outer circumferential portion 3 of the upper surface of the metal base. Next, in consideration of mounting elements, circuit boards, etc., a heat cycle was performed three times in which the device was moored at 405° C. for 5 minutes in the atmosphere and then left at room temperature.

Conventionally, it was thought that Cu-W alloys could not be hermetically sealed with glass, but even if the helium leak rate was tested with a He leak detector,
It became possible to achieve high air sealing with the following:

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, the present invention is based on the unique feature that the metal base and the lead are hermetically sealed through a plating layer of a specific alloy. It is possible to provide a hermetically sealed metal package for a semiconductor using a metal base material of -W alloy, Cu-Mo alloy, or Cu-W-Mo alloy; (2) Cu-W alloy, Cu-Mo alloy, Cu-
The use of W-Mo alloy has high thermal conductivity, which allows for higher density mounting and greater output power than when conventional sealing metals are used; This has the effect of providing a hermetically sealed metal package for semiconductors.

Note that the present invention is not limited to the shape of the package shown in the embodiments, and can be applied to a stand or stem on which various optical related elements such as a laser diode, a light emitting diode, a photodiode, etc. are mounted, and a stand on which high frequency related elements are mounted. It can also be advantageously applied to metal bases that require high heat dissipation.

[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 it has a plating layer of Ni-P alloy. (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 Ni-P alloy plating layer deposited on the surface of the glass sealing part has a P content of 3 to 12 wt%. Hermetically sealed metal package.