JP2003078054A - Electronic component device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic component device with which a thermal stress is distributed and airtightness is improved after sealing. SOLUTION: In this electronic component device, an electronic component element 5 is housed in a cavity 4, with which a junction electrode 8 is formed around an opening, of a substrate 2. The cavity 4 is sealed by bonding a metal lid 3 for sealing through a sealing member 7 to the junction electrode 8. In this electronic component device, the junction electrode 8 has a sealing member bonding area 8x composed of a base electrode layer 8a and a surface plating layer 8b, and a sealing member non-bonding area 8y composed of the base electrode 8a only.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component element used in a transmission / reception control circuit of a high frequency communication device, for example, a SAW.
The present invention relates to an electronic component device in which an element is housed in a cavity formed in a substrate such as a multilayer circuit board or a container and hermetically sealed.

[0002]

2. Description of the Related Art For example, an electronic component element used in a transmission / reception control circuit of a high frequency communication device, for example, a SAW element is Li
A comb-teeth-shaped Al electrode was formed on the surface of a piezoelectric substrate of TaO ₃ , LiNbO ₃ , Li ₂ Nb ₄ O ₇ or the like. Such a SAW element is an element that uses the surface wave of the piezoelectric substrate and must be used particularly in an environment where foreign matter and moisture do not adhere to the comb-teeth-shaped electrode portion. Therefore, the SAW element has been housed in a cavity of a substrate such as a multilayer circuit board having a cavity structure or a container body, and hermetically sealed by a sealing metal lid.

FIG. 3 shows an electronic component device using an electronic component element having such a structure. In FIG.
A cavity 14 is formed on one surface side of the base 12, and a connection electrode pad for connecting to a predetermined circuit network is formed on the bottom surface of the cavity 14 for accommodating an element. The connection electrode pad is provided with an electron such as a SAW element. The component element 15 is flip-chip mounted via the bump 16. The metal lid 13 for sealing was joined to the opening of the cavity 14 via the sealing member 17. The structure of this sealing portion 17 is shown in FIG.

The substrate 12 is made of a material having a high airtightness such as a ceramic material. In particular, a multi-layered substrate of alumina has high strength and is excellent in reliability, and is therefore commonly used.

Typical sealing methods are solder and Au-S.
A solder seal method using an n alloy, a seam ring brazed around the cavity, and a seam weld method in which a sealing metal lid is sealed by seam welding to this seam ring. A glass sealing method is known in which a substrate and a lid are bonded using the glass sealing method. And
These sealing methods have high airtightness and excellent reliability.

FIG. 4 shows a sealing structure of the solder seal method using a brazing material. That is, a bonding electrode composed of the base electrode layer 18a and the surface plating layer 18b is formed around the opening of the cavity 14, and the surface plating layer 18b of the bonding electrode and the outer peripheral portion of the inner surface of the sealing metal lid 13 are formed. Are joined via a sealing member 17a such as solder or Au—Sn alloy. In the seam weld method, the bonding electrode composed of the base electrode layer 18a and the surface plating layer 18b is bonded with Ag brazing such as a seam ring, and the sealing metal lid 13 is placed on the seam ring. The outer peripheral portion of the sealing metal lid 13 was joined to the seam ring by welding.

The above-mentioned sealing metal lid 13 has a coefficient of thermal expansion of the base material so that a concave warp does not occur in the base 12 at the time of sealing or after mounting the electronic component device on the printed wiring board. A material having a small difference from the expansion coefficient is used.
For example, if the substrate 12 is a multilayer substrate made of alumina, the coefficient of thermal expansion is 7 × 10 ⁻⁶ / ° C., and the sealing metal lid is made of Kovar (coefficient of linear thermal expansion: 4.5 to 5.1). × 10 ^-6 / ℃)
And so on. However, it was difficult to make the coefficients of thermal expansion of the respective materials of the base 12 and the sealing metal lid 13 completely match.

[0008]

In the joint structure as shown in FIG. 4, the joint portion between the base body 12 and the sealing metal lid 13 is subjected to a heat stress sealing step, and a predetermined circuit structure is formed on the surface of the base body 12. In the step of mounting the component by the reflow process, the step of mounting the component on the printed wiring board, and the like, there is a problem that cracks are likely to occur particularly from the edge of the surface plating layer 18b.

In this, the edge of the base electrode layer 18b, the edge of the surface plating layer 17, and the edge of the sealing member 17a attached to the bonding electrode are the same in the area surrounded by the circle 19.

After the above-described heat application step, the stress of thermal stress due to the difference in thermal expansion coefficient is concentrated on the edge of the base electrode layer 18b, the edge of the surface plating layer 17, and the edge of the sealing member 17a. I will end up. The surface plating layer 18b is deposited on the surface of the base electrode layer 18a by plating, but since the plating layer is deposited on the edge of the base electrode layer 18a, the plating solution is eroded from the edge. That is, the bonding strength between the base electrode layer 18b and the substrate 12 is reduced in some portions. Then, cracks are likely to occur in the surface plating layer 18b at such edge portions.

As described above, if a crack or the like is generated at the outer edge of the surface plating layer 18b, there is a problem that the airtightness inside the cavity 14 is greatly reduced.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to effectively suppress the occurrence of cracks even if thermal stress is applied to the joint portion of the sealing lid, and to improve airtightness. An expensive electronic component device is provided.

[0013]

According to the present invention, there is provided a base having a cavity in which a bonding electrode is formed around an opening, an electronic component element housed in the cavity, and a sealing member for the bonding electrode. In an electronic component device including a metal sealing lid that is bonded and seals the cavity, the bonding electrode includes a sealing member bonding region including a base electrode layer and a surface plating layer, and a sealing including only the base electrode. An electronic component device having a member non-bonding region. A base having a cavity in which a bonding electrode is formed around the opening, an electronic component element accommodated in the cavity, and a metal sealing lid which is bonded to the bonding electrode via a sealing member and seals the cavity. In an electronic component device including a body, the bonding electrode has a sealing member bonding region including a base electrode layer and a surface plating layer, and a sealing member non-bonding region including only the base electrode. It is a component device.

According to the present invention, the bonding electrode formed around the opening of the cavity is attached to the sealing member bonding region where the sealing metal lid is actually bonded through the sealing member and the sealing member is attached. And a non-bonded region. The sealing member bonding area of the bonding electrode has a laminated structure of the base electrode layer and the surface plating layer, and the sealing member non-bonding area of the bonding electrode is composed of only the base electrode layer. That is, the surface plating layer is not formed on the entire surface of the bonding electrode but is formed partially. That is, in the width direction of the bonding electrode, the sealing member bonding region in which the surface plating layer is formed is formed in the inner region close to the cavity, and the outer region is the base electrode layer only.

Since the surface plating layer is partially formed on the base electrode layer as described above, the edge of the surface plating layer, for example, the outer edge of the surface plating layer does not coincide with the edge of the base electrode layer. . That is, the edge of the interface between the sealing member and the surface plating layer and the edge of the interface between the surface plating layer and the base electrode layer do not coincide with the edge of the interface between the base electrode and the base. For this reason, the stress due to heat, which was a cause of cracks in the surface plating layer, does not concentrate on the edges of the sealing member, the surface plating layer, and the base electrode, and this stress is applied to the base electrode layers having different outer edges. Dispersed on the outer edge and the outer edge of the surface plating layer.

Further, since the edge portion of the surface plating layer is located in the central region where the thickness of the base electrode layer is stable, the plating solution forming the surface plating layer penetrates into the interface between the base and the base conductor layer. Since it does not corrode, the bonding strength between the bonding electrode and the substrate is increased, and this also effectively suppresses cracks generated from the edge of the surface plating layer.

As a result, the occurrence of cracks in the joint portion of the sealing metal lid is reduced even during the process of applying thermal stress and during mounting on the printed wiring board, and the electronic component device is highly airtight. Is obtained.

Regarding the crack from the edge of the bonding electrode near the cavity, the cavity side is the side that is hermetically sealed, and since moisture and the like do not particularly enter from the crack, the crack does not spread easily. There is no particular problem with the deterioration of airtightness.

[0018]

DETAILED DESCRIPTION OF THE INVENTION An electronic component device of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of the electronic component device of the present invention, and FIG. 2 is an enlarged view of the joint portion of FIG.

The electronic component device 1 is mainly composed of a substrate 2 having a cavity 4 formed therein, a sealing metal lid 3, and an electronic component element 5 such as a SAW element. Then, the electronic component element 5 is flip-chip mounted on the mounting bottom surface in the cavity 4 via the bump 6. Further, as shown in FIG. 4, the sealing metal lid 3 is bonded to a bonding electrode formed around the opening of the cavity 14 via a sealing member 7 to hermetically seal the cavity 14. is doing.

Here, the bonding electrode 8 is the base electrode layer 8a.
And the surface plating layer 8 partially adhered to the base electrode layer 8a
b. The region of the bonding electrode 8 on the cavity 14 side (inner region) is a sealing member bonding region 8x that is bonded to the sealing metal lid 3 via the bonding member 7a, and is separated from the bonding electrode cavity 14 side. The region (outer region) is a sealing member non-bonding region 8y to which the bonding member 7a does not adhere. The sealing member bonding region 8x of the bonding electrode 8 is composed of the base electrode layer 8a and the surface plating layer 8b deposited on the base electrode layer 8a. On the other hand, the sealing member non-bonding region 8y is composed only of the base electrode layer 8a. Then, this sealing member non-bonding region 8
On the base electrode layer 8a of y, a part of the substrate 2 is covered with, for example, an insulator layer 2a.

Materials constituting the electronic component device of the present invention are as follows.

With respect to the base 2, in recent years, electronic components have been integrated with a module to reduce the size of the electronic components comprehensively and reduce the cost. In a high-frequency module, Ag, Cu, etc. are contained in a built-in conductor. It consists of a low temperature firing substrate containing the low impedance material of

The electronic component element 5 is, for example, a SAW element, and a comb-teeth electrode such as aluminum is formed on the surface of a piezoelectric substrate such as LiTaO ₃ . Further, connection pads are formed on the surface of the piezoelectric substrate, and the bumps 6 are arranged on the connection pads.

The metal lid 3 for sealing has a coefficient of thermal expansion of the base body 2.
A material close to the coefficient of thermal expansion is selected and has a flat plate shape that can be bonded to the bonding electrode 8 around the opening of the cavity 4. For example, a low temperature fired base material whose base body 2 is made of glass or ceramic (having a thermal expansion coefficient of 9 to 11 × 10 ⁻⁶ /
C), the sealing metal lid 3 has a thermal expansion coefficient of 8 ×
For example, 45 alloy of 10 ⁻⁶ / ° C. is used. Moreover,
Further, N is so formed that the sealing member 7 can be brazed on the entire inner surface of the sealing metal lid 3 or on the outer peripheral portion thereof.
It is covered with i plating and Au plating.

The base electrode layer 8a of the bonding electrode 8 is formed simultaneously with the formation of the base 2. For example, a conductor film having a predetermined shape is formed on the base body 2 before firing by using a conductive paste, and the conductor film is fired together with the firing of the base body 2 to form a base electrode layer. The conductive paste is composed of a low-temperature sinterable metal powder such as Ag or Cu and a vehicle.

The surface plating layer 8b formed only in the sealing member bonding region 8x of the bonding electrode 8 is formed for the purpose of rust prevention of the surface and solder wetting. The surface plating layer 8b is generally Au plating, and for example, it is desirable to form an intermediate plating layer of Ni or the like under Au plating.

The sealing member 7 is for sealing other electronic parts after sealing.
Considering mounting on the surface of the substrate 2, Au-Su
Brazing with an alloy or seam welding with a seam ring is preferable. For example, in the case of brazing using Au—Su alloy or the like, the joining region of the joining electrode and the sealing metal lid 3
And are joined by brazing material. That is, the surface plating layer 8b
The brazing material is directly adhered to this. Further, sealing by seam welding using a seam ring is performed because the seam ring is bonded to the bonding area of the bonding electrode by a brazing material.
The brazing material is directly attached to the surface plating layer 8b. In addition, it is desirable that the brazing material that is the sealing member 7 be melted and formed around the inner surface of the sealing metal lid 3 in advance.

The sealing member non-bonding region 8 of the bonding electrode 8 is also provided.
The insulating layer 2a covering y may be a single layer located at the uppermost part of the insulating layer forming the base body 2, or may be a coating film formed by a thick film method using an insulating paste. .

The method of manufacturing the electronic component device of the present invention is as follows. First, an insulating ceramic green sheet that constitutes the base 2 is prepared, and a cavity is formed in each green sheet.
A through hole that defines the shape of 4 and a through hole that becomes a via hole conductor necessary for a predetermined internal circuit network is formed. After that, a conductive film is formed on each green sheet by printing a conductive paste on the base electrode layer 8b of the bonding electrode, the surface wiring pattern, the internal wiring pattern, the connection electrode pads located on the mounting bottom surface of the cavity 4, and the like. After that, a plurality of green sheets are laminated in accordance with the shape of the base body 2 to form an unfired laminated body, and further, the outer region of the conductor film (not the sealing member) to be the base electrode layer 8a of the bonding electrode 8 is formed. The bonding area 8y) is laminated with a green sheet or printed with a ceramic insulating paste. After that, the unfired laminate is collectively fired. That is, the base electrode layer 8a of the bonding electrode 8
The inner region of the substrate is exposed from the fired substrate, and the outer region of the base electrode layer 8a of the bonding electrode is part of the substrate 2 or the insulator layer 2.
will be covered with a.

Thereafter, the sealing member bonding area 8 of the bonding electrode 8 is formed.
Base electrode layer 8a to be x (exposed from the base 2)
Then, Ni plating and Au plating are performed to form the surface plating layer 8b in this region.

Next, the electronic component element 5 is faced down in the cavity 4 via the bump 6 and flip-chip mounted by thermal vibration pressure bonding.

Finally, a sealing process is performed. The metal lid 3 for sealing is previously made of Au80 on the entire inner surface or the outer peripheral portion.
%, Sn 20% brazing filler metal (sealing member 7) was melted and applied and placed on the base electrode layer of the bonding electrode 8 formed around the mouth of the cavity 4, and the oxygen concentration was controlled to 20 ppm or less. Peak temperature of 320 in N ₂ chamber
Sealed under a temperature profile of 280 ° C., 280 ° C. or higher for 90 seconds.

Next, the features of the present invention will be described. The feature of the present invention is that the bonding electrode 8 is
It is composed of a sealing member bonding region 8x which is a side and a sealing member non-bonding region 8y which is a part away from the cavity 4, and a surface plating layer 8b is formed in the sealing member bonding region 8x. Then, the sealing member non-bonding region 8y is formed on the base electrode layer 8
It is composed of only a and is covered by the insulator layer 2a.

That is, focusing on the surface plating layer 8b, the surface plating layer 8b is partially present on the base electrode layer 8a, and the outer edge portion of the surface plating layer 8b is located at the central portion of the base electrode layer 8a. , And the outer edge of the base electrode layer 8a does not match in position.

Therefore, when the metal lid 3 for sealing is sealed, other electrode parts are mounted on the surface of the base body 1, the electronic part device is mounted on a printed wiring board, and the like. Even if heat is applied to the entire component device and a stress is generated due to a difference between the thermal expansion coefficient of the base body 2 and the thermal expansion coefficient of the sealing metal lid body 3, the stress due to the thermal stress is applied to the sealing member 7 and the bonding electrode 8. Will be dispersed.

This thermal stress is due to the edge of the interface between the sealing member 7 and the surface plating layer 8b, the edge of the interface between the surface plating layer 8b and the base electrode layer 8a, and the interface between the base electrode layer 8a and the substrate 2. Edge part of the surface plating layer 8a, which is partially present on the underlying electrode layer 8a, the outer edge portion of the surface plating layer 8b is located in the central portion of the underlying electrode layer 8a, and the outer edge portion of the underlying electrode layer 8a is Since there is a positional disagreement with, it can be dispersed.

Moreover, since the outer edge portion where cracks are likely to occur in the surface plating layer 8b is the portion where the vicinity of the central portion of the base electrode layer 8b and the base body 2 are most stably joined, the base electrode layer 8a The plating solution is unlikely to be attacked, and the surface plating layer 8b can be stably applied, which also makes it difficult to effectively generate cracks.

As a result, the occurrence rate of cracks from the outer edge of the surface plating layer 8b is reduced, and high airtightness can be obtained.

As a result of conducting a He leak test as a method for evaluating the airtightness of a cavity, the present inventor generated 10% in the electronic component device 11 having the conventional structure. I was able to eliminate all defects. The He leak test at this time was performed at a peak temperature of 240 ° C.
It is carried out after passing through a reflow furnace held at 220 ° C. or higher for 30 seconds 5 times.

In the above description, an example in which the base material is made of a low temperature fired base material has been described, but the present invention can be similarly applied to other alumina multilayer substrates.

In the above description, the sealing metal lid 3 is also used.
In this example, the surface of the bonding electrode layer 8 and the surface plating layer 8b of the bonding electrode layer 8 are sealed with a brazing material.
Alternatively, the seam ring may be joined with a brazing material, the sealing metal lid 3 may be placed on the seam ring and joined by seam welding. In this case, in order to perform stable seam welding, the sealing metal lid 3 is arranged so as to protrude from at least the insulator layer 2a.

[0042]

As described above, according to the present invention, in the bonding electrode formed around the opening of the cavity, the sealing bonding region is the base electrode layer and the surface plating layer, and the sealing non-bonding region is the base electrode layer. Formed with only. Moreover, the non-sealing region is covered with the insulating layer.

As a result, even if stress due to the difference in thermal expansion and contraction between the sealing metal lid and the base body is applied, mutual peeling stress caused by the difference in thermal expansion coefficient between the base body and the lid body causes mutual peeling stress of the surface plating layer. Dispersed at the edge of the interface and at the edge of the interface between the bonding electrode and the substrate.

Further, the end portion of the base electrode layer of the bonding electrode is less likely to be eroded by the plating solution, and the bonding strength between the bonding electrode and the substrate can be increased.

By these actions, the occurrence of cracks in the bonding electrode between the substrate and the sealing metal lid is reduced, and an electronic component device having high airtightness can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an electronic component device of the present invention.

FIG. 2 is an enlarged view of a joint portion between the base of the present invention and a sealing metal lid.

FIG. 3 is a schematic sectional view of a conventional electronic component device.

FIG. 4 is an enlarged view of a joint portion between a conventional base body and a sealing metal lid body.

[Explanation of symbols]

1 ・ ・ ・ Electronic component device 2 ... Base 2a ... Insulator layer 3 ... Lid 4 ... Cavity 5: Electronic component element 6 ... Bump 7 ... Sealing member 8 ... Bonding electrode 8a ... Base electrode layer 8b ・ ・ ・ Surface plating layer 8x sealing member joining area 8y Sealing member non-bonding area

Claims (2)

[Claims] 1. A base having a cavity in which a bonding electrode is formed around an opening, an electronic component element housed in the cavity, and the bonding electrode are bonded to each other via a sealing member to seal the cavity. In the electronic component device including the metal sealing lid, the bonding electrode has a sealing member bonding region including a base electrode layer and a surface plating layer, and a sealing member non-bonding region including only the base electrode. An electronic component device. 2. The sealing member non-bonding region of the bonding electrode,
The electronic component device according to claim 1, wherein the electronic component device is covered with a part of the substrate.