JP2004356396A - Electronic component receiving vessel and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component storing vessel and an electronic device excellent in resistance to heat so as to be capable of securing the air tightness of the electronic device even when the thermal hysteresis of 230-240°C is applied thereon upon mounting the electronic device, and also excellent in the mechanical strength of a sealing material as well as reliability against thermal fatigue. <P>SOLUTION: The electronic component storing vessel 5 is provided with a substrate 2 equipped with a mounting unit 1 formed on the upper surface thereof to mount the electronic component, and a solder layer 4 applied on the whole periphery of the upper surface of a metallized layer 3 formed on the whole periphery of circumference of upper surface of the substrate 2 and containing gold other than the principal constituent of tin. The content of gold in the outer peripheral side of the solder layer 4 is higher than that of the inner peripheral side of the same in the electronic storing vessel 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic component storage container and an electronic device for hermetically sealing and storing electronic components such as a semiconductor element and a piezoelectric vibrator, and particularly to performing sealing using a low melting point alloy as a sealing material. The present invention relates to a container for storing electronic components.
[0002]
[Prior art]
Conventionally, an electronic component storage container for storing an electronic component such as a semiconductor element is made of an electrically insulating material such as an aluminum oxide sintered body, and a concave portion for storing the electronic component near the center of the upper surface thereof. An insulating base having a plurality of metallized wiring layers made of a refractory metal such as tungsten or molybdenum led out from the periphery to the lower surface, and a metallized metal layer for sealing applied on the outer peripheral portion of the upper surface; It is composed of Then, an electronic component such as a semiconductor element is bonded to the bottom surface of the concave portion of the insulating base via an adhesive, and each electrode of the electronic component is connected to a metallized wiring layer via a bonding wire or the like. A lid is sealed to the layer with a sealing material, and a container formed of the insulating base and the lid is hermetically sealed to provide an electronic device as a final product.
[0003]
In such a conventional electronic device, a gold-tin alloy containing 80% of gold or a solder containing lead as a main component is used as a sealing material for joining the insulating base and the lid.
[0004]
However, when a gold-tin alloy containing 80% of gold is used, the price of the product is high, so that there is a problem that the product to be used is limited. In addition, for lead-based solder, lead contained in the sealing material is specified as an environmental pollutant, and electronic devices using lead-containing solder are discarded or left outdoors and exposed to the weather. In this case, there is a risk that lead may be dissolved in the environment and contaminate the environment. For this reason, in recent years, with the rise of the global environmental protection movement, a lead-free sealing material has been required.
[0005]
Therefore, various types of sealing materials that do not use lead, which is harmful to the human body, have been developed and proposed. As such sealing materials, for example, various types of materials mainly containing tin, bismuth-silver, zinc-aluminum, etc. Solder has been adopted.
[0006]
[Patent Document 1]
JP 2000-307228 A
[Problems to be solved by the invention]
However, although solder made of an alloy containing tin, silver, and zinc shows excellent reliability in thermal fatigue resistance under a temperature cycle of −55 to 125 ° C., the melting points of these solders are all low. Since the temperature is 225 ° C. or lower, this solder is used as a sealing material for hermetically sealing the insulating base and the lid, and the heat history at 230 to 240 ° C. when the electronic device is mounted on an external electric circuit or the like. When added to the sealing material, there is a problem that the sealing material itself melts and the hermetic sealing inside the electronic device is broken.
[0008]
In addition, a solder containing bismuth-silver as a main component is inferior in thermal fatigue resistance under a temperature cycle of −55 to 125 ° C. and lacks in hermetic reliability, so that it is not suitable for use in hermetic sealing of electronic devices. There was a problem that it was appropriate.
[0009]
In addition, zinc-aluminum-based solder tends to corrode when left in the air and lacks long-term airtight reliability, so it is also unsuitable for hermetic sealing of electronic devices. There was a problem that.
[0010]
Accordingly, the present invention has been completed in view of such a conventional problem, and has as its object the purpose of mounting an electronic device on an external electric circuit or the like even if a heat history of 230 to 240 ° C. is applied. An object of the present invention is to provide an electronic component storage container and an electronic device that can ensure airtightness, have excellent corrosion resistance and mechanical strength of a sealing material itself, and do not contain lead and thus do not pollute the global environment.
[0011]
[Means for Solving the Problems]
An electronic component storage container according to the present invention includes a base on which a mounting portion for mounting an electronic component formed on an upper surface is formed, a metallized layer formed over the entire periphery of the upper surface of the base, and a metallized layer. And a solder layer containing tin as a main component and containing gold applied over the entire periphery of the upper surface of the electronic component storage container, wherein the outer peripheral side of the solder layer has a higher gold content than the inner peripheral side. It is characterized by being expensive.
[0012]
According to the electronic component storage container of the present invention, the solder layer containing tin as a main component and containing gold, which is applied over the entire periphery of the upper surface of the metallized layer of the insulating base, contains gold on the outer peripheral side rather than the inner peripheral side. It is a lead-free solder containing tin as a main component on the inner peripheral side and having excellent mechanical strength and thermal fatigue reliability.
[0013]
Further, since the outer peripheral side of the solder layer has a high gold content, the outer peripheral side is an alloy layer region having a melting temperature of 250 ° C. or higher. As a result, even when a heat history of 230 to 240 ° C. is applied to the solder layer, the solder layer is not melted and the hermetic seal inside the container is not broken. An electronic component storage container having both the characteristics of a solder layer having excellent heat resistance and the characteristics of a solder layer having excellent heat resistance on the outer peripheral side can be obtained.
[0014]
Further, the electronic device of the present invention is mounted on the upper surface of the base via the solder layer so as to cover the electronic component storage container, the electronic component mounted on the mounting portion, and the mounting portion. And a lid.
[0015]
According to the electronic device of the present invention, the electronic device includes the electronic component storage container, the electronic component mounted on the mounting portion, and the lid attached via a solder layer so as to cover the mounting portion. Therefore, an electronic device having heat resistance enough to withstand the heat history of 230 to 240 ° C. when mounting the electronic device on an external electric circuit or the like, and having sealing properties excellent in mechanical strength and thermal fatigue reliability. Can be.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an electronic component storage container (hereinafter, also referred to as a container) of the present invention will be described in detail with reference to the accompanying drawings.
[0017]
FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic component storage container and an electronic device according to the present invention, in which 1 is a mounting portion on which an electronic component is mounted, 2 is a base on which a mounting portion 1 is formed, Reference numeral 3 denotes a metallized layer formed all around the upper surface of the base 2, 4 denotes a solder layer containing tin as a main component and containing gold, which is applied over the entire upper surface of the metallized layer 3, and 5 denotes an electronic component housing Container. Reference numeral 6 denotes an electronic component mounted on the mounting portion 1 of the base 2, reference numeral 7 denotes a cover attached to the upper surface of the base 2 via the solder layer 4 so as to cover the mounting portion 1, and reference numeral 8 denotes an electronic component. And a bonding wire for connecting the metallized wiring layer (not shown) of the base 2 to the metallized wiring layer. FIG. 2 is an enlarged sectional view of the main part.
[0018]
The base 2 is provided with a concave portion for accommodating the electronic component 6 at the center of the upper surface, and the electronic component 6 is bonded and fixed to the bottom surface of the concave portion via an adhesive such as glass, resin, or brazing material. .
[0019]
Further, a plurality of metallized wiring layers (not shown) are formed from the concave portion of the base 2 to the outside, and each electrode of the electronic component 6 is electrically connected to one end of the metallized wiring layer via a bonding wire 8. An external electric circuit (not shown) is electrically connected to a portion led out of the metallized wiring layer.
[0020]
The base 2 is made of an electrically insulating material such as a sintered body containing aluminum oxide, mullite, aluminum nitride, silicon carbide, glass ceramics or the like as a main component. (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), magnesia (MgO) and other suitable raw materials are mixed with a suitable organic solvent and solvent to form a slurry. A ceramic green sheet is obtained by forming into a sheet shape by employing a blade method, a calendar roll method, or the like, and thereafter, a plurality of ceramic green sheets are punched into a predetermined shape and laminated, and fired at a temperature of about 1600 ° C. Produced by
[0021]
The metallized wiring layer and the frame-shaped metallized layer 3 formed over the entire periphery of the upper surface of the substrate 2 are made of a refractory metal such as tungsten, molybdenum, or manganese, and an organic solvent or a solvent is added to these powders. Each of the mixed metal pastes is applied to a predetermined position of the ceramic green sheet in a predetermined pattern by a conventionally known screen printing method, and is formed by firing simultaneously with the ceramic green sheet. In addition, it is preferable to apply nickel, gold, or the like to the surface of the frame-shaped metallized layer 3 by a plating method or the like because the metallized layer 3 can be improved in heat resistance during sealing and serves as an antioxidant layer.
[0022]
The lid 7 is made of, for example, a metal such as a 42 alloy or an iron-nickel-cobalt alloy, or a sintered body mainly composed of aluminum oxide, mullite, aluminum nitride, silicon carbide, glass ceramic, or the like, similar to the base 2. When the lid 7 is made of a metal and is made of a metal, it is manufactured by punching a base material to be the lid 7 with a punching die having a shape corresponding to the lid 7, and when the lid 7 is made of a ceramic. Is manufactured by a method similar to that of the above-described base 2, and a metallized layer or a plating layer for solder bonding of various metals is formed in a region attached to the upper surface of the base 2 via the solder layer 4. In the case where the lid 7 is made of metal, a metallized layer or a plating layer for solder bonding of various metals may be formed in a region attached to the upper surface of the base 2 via the solder layer 4.
[0023]
Then, the lid 7 is joined to the metallized layer 3 formed around the upper surface of the base 2 via the solder layer 4 made of lead-free solder containing tin as a main component. At this time, by using the solder layer 4 having a higher gold content on the outer peripheral side as compared with the inner peripheral side (mounting section 1 side) on which the electronic component is mounted, heat resistance, mechanical strength, heat The electronic component storage container 5 having excellent reliability regarding fatigue is obtained.
[0024]
Solder made of an alloy containing tin as a main component and containing silver or copper is highly reliable, but has a melting point of 225 ° C. or less. In addition, when the solder composed of an alloy containing silver or copper containing tin as a main component further contains 25% or more of gold, the liquid layer temperature becomes 250 ° C. or more, and the heat resistance becomes higher. It becomes brittle and its mechanical strength and reliability against thermal fatigue are inferior to those of solders with a low gold content.
[0025]
When the metallization layer 3 and the lid 7 are sealed with solder, tin does not form an alloy only with a metal such as gold, silver, or copper added to the solder, but actually forms metallization. An alloy is also made with nickel and gold plated on the layer 3 and the lid 7. Since the concentration of gold in the solder related to the increase in the melting point is a concentration with respect to the tin component not forming an alloy with another metal, the amount of gold actually added to the solder is 25% or less. However, the melting point may be 250 ° C. or higher. In the configuration of the present embodiment, the melting point is set to 250 ° C. or higher by adding 10% or more of gold to the solder in the portion (outer peripheral side) where heat resistance is required.
[0026]
In the present invention, the solder layer 4 is a solder containing tin as a main component. For example, an alloy having a gold content of 5% or less is used on the inner peripheral side (the mounting portion 1 side) of the solder layer 4. On the side, a solder layer 4 made of solder having a higher gold content on the outer peripheral side than on the inner peripheral side of the sealing portion was realized by a method such as using an alloy having a gold content of 10% or more. As a result, the solder on the inner peripheral side becomes a solder layer 4 having a low melting point but high mechanical strength and high thermal fatigue reliability, and the solder on the outer peripheral side becomes a heat-resistant solder layer 4 having a high melting point. The sealing portion between the substrate and the base 2 can be sealed with good heat resistance, mechanical strength, and thermal fatigue reliability.
[0027]
As a result, even when a heat history of 230 to 240 ° C. is applied to the solder layer 4 when the electronic device after mounting the electronic component 6 is mounted on an external electric circuit or the like, the solder layer 4 is melted and the electronic component is stored. The hermetic seal inside the container 5 does not break.
[0028]
Such a solder layer 4 may be formed of a tin-silver, tin-copper or tin-silver-copper solder containing gold containing 0 to 5% on the inner circumference and 10% to 30% on the outer circumference. In addition, such a lead-free solder is preferable because there is no risk of polluting the global environment after the electronic device is discarded.
[0029]
The solder layer 4 only needs to have the above-described gold content in the solder after sealing, and the solder does not necessarily need to be provided in a double ring shape. For example, gold plating is performed in advance on the sealing surface of the base 2 or the lid 7 or on both sides with different thicknesses of gold plating on the inner peripheral side and the outer peripheral side, and when appropriately heated and melted while pressing with solder as a sealing material, the gold becomes Since it is easily diffused into the solder, gold is diffused into the solder at the same time as the solder is melted. At the same time, the air in the container expands due to the heat, so that the solder is entirely pushed out. As a result, the gold-containing solder on the inner peripheral side is wetted and spread on the outer gold plating layer while the gold concentration increases due to the gold in the gold plating layer. This results in a solder layer 4 having a high gold content on the side.
[0030]
The solder layer 4 may be previously attached to the lid 7 or the base 2.
The base 2 and the lid 7 are joined by placing the two types of solder having different gold contents in a double ring shape between the frame-shaped metallized layer 3 and the lid 7 of the base 2. Then, the lid 7 is placed on the substrate 2 so as to sandwich the same, and then the lid 7 is pressed against the substrate 2 at a constant pressure while the peak temperature is about 250 to 300 ° C. and the nitrogen atmosphere is sealed. According to the method in which the solder layer 4 is melted by holding it in a furnace for 0.5 to 20 minutes, the outer peripheral side of the upper surface of the metallized layer 3 has a higher gold content than the inner peripheral side through the solder layer 4. The lid 7 is joined to the electronic component housing container 5 of the present invention, which is hermetically sealed.
[0031]
Thus, according to the electronic component storage container 5 of the present invention, the electronic component 6 such as a semiconductor element is bonded to the mounting portion 1 provided on the bottom surface of the concave portion of the base 2 via an adhesive or the like, and at the same time, The electrodes are connected to the metallized wiring layer via bonding wires 8 and the like. Thereafter, the base 2 and the lid 7 are placed so as to sandwich the solder layer 4, the solder layer 4 is heated and melted, and the container is sealed. By stopping, it becomes an electronic device as a final product having excellent heat resistance, mechanical strength and thermal fatigue reliability.
[0032]
The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the electronic device is configured such that the concave portion is formed in the base 2 and the flat cover 7 is sealed, but the lower surface facing the flat base 2 and the mounting portion 1 of the electronic component 6. The lid 7 provided with a concave portion at the portion may be sealed.
[0033]
In addition, a semiconductor device is taken as an example of the electronic component 6, and an electronic device containing the semiconductor device has been described in detail. However, an electronic device containing the electronic component 6, such as a piezoelectric vibrator, a surface acoustic wave device, and a bulk acoustic wave device, an acceleration sensor The present invention is also applicable to an electronic device containing sensor components such as a sensor and an angular velocity sensor.
[0034]
【The invention's effect】
According to the electronic component storage container of the present invention, the solder layer containing tin as a main component and containing gold, which is applied over the entire periphery of the upper surface of the metallized layer of the insulating base, contains gold on the outer peripheral side rather than the inner peripheral side. Features of high heat-resistant alloy layer with high content of gold whose melting temperature is 250 ° C or higher due to high ratio, and features of high reliability alloy layer with low content of gold that is excellent in mechanical strength and thermal fatigue reliability And can also be provided. As a result, even if a heat history of 230 to 240 ° C. is applied to the solder layer, the solder layer does not melt and the airtightness inside the container is not broken, and at the same time, the mechanical strength and thermal fatigue reliability of the sealing are reduced. A good container for storing electronic components can be obtained.
[0035]
According to the electronic device of the present invention, the electronic component storage container, the electronic component mounted on the mounting portion, and the lid attached to the upper surface of the base via the solder layer so as to cover the mounting portion. With its body, it has sealing properties with excellent mechanical strength and thermal fatigue reliability, as well as heat resistance to withstand the heat history of 230 to 240 ° C. when mounting the electronic device on an external electric circuit or the like. It can be an electronic device.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of an embodiment of an electronic device using an electronic component storage container of the present invention.
FIG. 2 is an enlarged sectional view of a main part of the electronic device of FIG. 1;
[Explanation of symbols]
1 Mounting part 2 Base 3 Metallization layer 4 Solder layer 5 Electronic component storage Container 6 ····· Electronic component 7 ····· Lid

Claims (2)

A base on which an electronic component formed on the upper surface is mounted, a metallized layer formed over the entire periphery of the upper surface of the base, and a metallized layer formed over the entire upper surface of the metallized layer; An electronic component storage container comprising: a tin-based solder layer containing gold as a main component, wherein the solder layer has a higher gold content on the outer peripheral side than on the inner peripheral side. container. 2. The electronic component storage container according to claim 1, comprising: an electronic component mounted on the mounting portion; and a lid attached to the upper surface of the base via the solder layer so as to cover the mounting portion. An electronic device, comprising:

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