JPH05114662A - Electronic part airtight sealing case and sealing method thereof - Google Patents

Abstract

PURPOSE:To provide an airtight sealing case having no residual stress harmful to quality by simultaneously performing thermal bonding of the rear face of an electronic part, such as semiconductor chip, and the bottom face of the cap and airtight bonding of the case body and the rim of the cap, and making adjustments to align both parts. CONSTITUTION:A junction between the body 1 of an airtight sealing case and the cap 6 thereof is airtightly sealed with brazing material 10. This junction is provided with a mechanism 9 to relieve stress produced during this airtight sealing process. The stress relief mechanism is constituted of a combination of a looped body provided with a continuous groove and parts in a shape corresponding to that of the groove.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetically sealed container for electronic parts for housing electronic parts such as semiconductor chips.

[0002]

2. Description of the Related Art Conventionally, in a hermetically sealed container for electronic parts such as a semiconductor chip, the back surface of the semiconductor chip or the like, which is connected face down to the wiring layer on the base of the hermetically sealed container, is adhered to the bottom surface of the cap by a brazing material. However, it has been known that heat generated by the operation of the semiconductor chip or the like is radiated through the cap, while the edge portion of the cap and the base of the hermetically sealed container are adhered by a brazing material to hermetically seal them.

[0003]

However, conventionally, a brazing material between the back surface of the electronic component such as a semiconductor chip and the bottom surface of the cap by a brazing material, and a brazing material between the edge portion of the cap and the hermetically sealed container substrate. It has been difficult to perform the two-point bonding by the same process in the same step for the reason described later.

4 (A) to 4 (C) are explanatory views of a conventional sealing process of a hermetically sealed container for electronic parts. In this figure, 21 is a hermetically sealed container base, 22 is a connecting pin, 23 is a TAB inner lead, 24 is a semiconductor chip, 25 is a connecting bump, 26 is a cap, 27 is a brazing material, 28 is a metallized layer, 29 Is a brazing material.

In the conventional hermetically sealed container shown in FIG. 4A, adhesion between the back surface of the semiconductor chip and the bottom surface of the cap by a brazing material and between the edge of the cap and the hermetically sealed container base. In order to perform the two-point bonding of the brazing filler metal in the same step, the T formed on the hermetically sealed container substrate 21 which is the multilayer ceramic wiring layer having the connection pins 22.
AB (Tape Automated Bondin
The semiconductor chip 24 is face-down connected to the inner lead 23 of g) by the connecting bump 25, the brazing material 27 is placed on the back surface of the semiconductor chip 24, and the edge of the cap of the hermetically sealed container base 21 is fixed. A similar brazing material 29 is also placed on the sealing portion and heated to form brazing materials 27 and 2
When 9 is melted, pressure is applied to cover the back surface of the semiconductor chip 24 and the bottom surface of the cap 26 when the cap 26 is covered, and at the same time, pressure is applied to the edge portion of the cap on the hermetically sealed container base 21. It is necessary.

However, it is impossible to exclude variations in the thickness of the semiconductor chip 24 itself, differences in the thickness depending on the type of the semiconductor chip 24, and variations in the height that occur when the semiconductor chip 24 is fixed to the inner leads 23. Therefore, as shown in FIG. 4B, when the height of the back surface of the semiconductor chip 24 is high, the adhesion between the hermetically sealed container base 21 and the edge of the cap 26 is incomplete, and sometimes a gap is left. In some cases, a perfect hermetic seal could not be achieved.

When the height of the back surface of the semiconductor chip 24 is low, as shown in FIG.
The pressure concentrates on the bonded portion between the edge portion of the cap 26 and the cap 26, and the pressure is applied more than necessary, the airtightly sealed container base 21 is cracked, or the residual stress causes a quality problem in which it cannot withstand the subsequent temperature change. Could cause.

In addition to the above-mentioned longitudinal stress, the edge of the cap expands outward when pressure is applied to the cap, and contracts inward when pressure is removed. Lateral stress was also generated.

That is, in the structure of the sealing portion of the conventional hermetically sealed container, the adhesion between the back surface of the semiconductor chip and the bottom surface of the cap by the brazing material and the gap between the hermetically sealed container base 21 and the edge portion of the cap. It was impossible to reduce the dimensional error when airtight adhesion was performed in the same process.

According to the present invention, the adhesion for thermally coupling the back surface of the electronic component such as a semiconductor chip and the bottom surface of the cap and the airtight adhesion between the hermetically sealed container substrate and the edge portion of the cap are simultaneously performed. Moreover, it is an object of the present invention to provide a hermetically sealed container in which the positional displacement between both members is adjusted and no residual stress that is harmful to quality is left.

[0011]

In the hermetically sealed container for electronic parts according to the present invention, it occurs when the hermetically sealed container base and the cap are hermetically sealed with the brazing material. A mechanism to relieve stress is adopted.

In this case, as a mechanism for relieving the stress generated at the time of hermetically sealing, a member having a continuous groove formed on the edge portion of the hermetically sealed container base body or the cap is fitted to the member. A ring-shaped body has been adopted.

Further, in the method for sealing an airtight container for electronic parts according to the present invention, since the airtight sealing is performed at a portion where the base of the airtight container and the cap are hermetically sealed by the brazing material, the brazing is performed. A mechanism is provided so that the edge of the cap does not come into contact with the hermetically sealed container base when the material is melted, and occurs between the hermetically sealed container base and the cap in the process of solidifying the brazing material. The process of relieving stress was adopted.

[0014]

When the portion for hermetically sealing the base of the hermetically sealed container and the cap with the brazing material as in the present invention is composed of, for example, a member having a continuous groove and an annular body having a shape conforming to the groove, When the brazing material is melted, there is no constraint between the hermetically sealed container base and the edge of the cap, so that the stress generated when hermetically sealing can be relieved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is an explanatory view of a hermetically sealed container for electronic parts according to the first embodiment. In this figure, 1 is a hermetically sealed container substrate, 2 is a connection pin, 3 is a TAB inner lead, 4 is a semiconductor chip, 5 is a connection bump, 6 is a cap, 7 is a brazing material, 8 is a metallized layer, 9 Is a stress relaxation mechanism, and 10 is a brazing material.

The hermetically sealed container of this embodiment and the sealing method thereof will be described. The inner lead 3 of the TAB formed on the hermetically sealed container substrate 1 which is a multilayer ceramic wiring layer having a large number of connection pins 2. , The semiconductor chip 4 is connected by the connecting bumps 5, the brazing material 7 is placed on the back surface of the semiconductor chip 4, and the continuous groove is arranged in the portion for sealing the edge of the cap of the hermetically sealed container base 1. In the groove of the stress relaxation mechanism 9 which is an annular body having
0 is placed, the brazing filler metals 7 and 10 are melted by heating, the cap 6 is covered, and pressure is applied so that the back surface of the semiconductor chip 4 and the bottom surface of the cap 6 come into close contact with each other.

At this time, the edge portion of the cap is immersed in the molten brazing filler metal in the groove of the stress relaxation mechanism 9 arranged on the hermetically sealed container base body 1 and can move freely. Even if there is a variation in the height of the back surface or a lateral displacement occurs, no stress is generated in the hermetically sealed container body.

In the present embodiment, the back surface of the semiconductor chip,
The bottom surface of the cap, the inner side of the groove of the annular body, which is a stress relaxation mechanism, and the edge of the cap are plated with solder which is a brazing material in advance, or have a surface finish with a material having good solder wettability. Is desirable.

Then, the edge portion of the cap is dimensioned to fit in the V-shaped or U-shaped groove of the stress relaxation mechanism, and the depth and width of the groove have variations in height of the back surface of the semiconductor chip, It must be deep enough to absorb the lateral deformation of the cap and deep enough to secure the cap with brazing material with sufficient strength.

Further, it is necessary that the bottom surface of this stress relaxation mechanism has an area sufficient to be fixed to the hermetically sealed container substrate with a required strength. If the bottom surface of the stress relaxation mechanism of this embodiment is adhered to the hermetically sealed container substrate with a brazing material having the same melting point as the brazing material of other parts, the stress relaxation mechanism itself slides laterally in the sealing process. Therefore, a large lateral shift is also absorbed here.

According to this embodiment, the semiconductor chip and the cap can be relatively vibrated (scrubbed) in a plane while the brazing material is melted, and the semiconductor chip and the cap can be relatively scrubbed with each other between the back surface of the semiconductor chip and the bottom surface of the cap. It is possible to improve the wettability of the brazing material.

When the present invention is applied to a hermetically sealed container for electronic parts of the type in which fins are attached to the outside of the cap to improve the heat radiation effect, the bottom surface of the cap loses elasticity and plasticity and has rigidity, It is even more effective.

Next, another specific structure of the above stress relaxation mechanism will be described. 2 (A)-(D), FIG. 3 (E)-
(H) is an explanatory view of a structure of a stress relaxation mechanism of another embodiment. In this figure, 11 is a hermetically sealed container base, 12 is a cap, and 13 to 20 are stress relaxation mechanisms.

Second Embodiment (see FIG. 2A) In this embodiment, as the stress relaxation mechanism 13, a cylindrical annular member provided on the hermetically sealed container base 11 and a cylinder of the cap 12 are provided. The brazing material is held between the edges. This embodiment mainly has an effect of absorbing the stress due to the displacement in the vertical direction.

(Third Embodiment) (See FIG. 2B) In this embodiment, as the stress relaxation mechanism 14, a double cylindrical annular member provided on the hermetically sealed container base 11 and a cap are used. Twelve cylindrical edges are combined and a brazing material is held in a double cylindrical annular member.

(Fourth Embodiment) (See FIG. 2C) In this embodiment, as the stress relaxation mechanism 15, a cylindrical annular member provided on the hermetically sealed container base 11 and the edge of the cap 12 are provided. The groove-shaped members formed in the section are combined, and the brazing material is held in the groove-shaped members. In addition,
The sealing process of this embodiment is performed upside down.

(Fifth Embodiment) (See FIG. 2D) In this embodiment, as the stress relaxation mechanism 16, a groove formed in the hermetically sealed container base 11 and a cylindrical edge portion of the cap 12 are provided. Combined, the brazing material is held in the groove.

(Sixth Embodiment) (See FIG. 3E) In this embodiment, as the stress relaxation mechanism 17, a cylindrical member provided on the hermetically sealed container base 11 and having one end edge folded back is used. The structure is such that the cylindrical edges of the cap 12 having the folded back edges are combined and the brazing material is held at the folded back portions. In the sealing step of this embodiment, after combining the cylindrical member whose one end edge is folded back and the cylindrical edge part of the cap 12 whose end part is folded back, the cylindrical member whose one end edge is folded back is sealed. It is carried out by fixing to the tightly sealed container base 11.

(Seventh Embodiment) (See FIG. 3F) In this embodiment, as the stress relaxation mechanism 18, an annular member having an inclined surface provided on the hermetically sealed container base 11 and the cap 12 are provided. The brazing material is held between the inclined edges of the. This embodiment has a degree of freedom with respect to the positional displacement in the horizontal direction as well as the positional displacement in the vertical direction.

(Eighth Embodiment) (See FIG. 3G) In this embodiment, as the stress relaxation mechanism 19, an L-shaped annular member provided on the hermetically sealed container base 11 and an L of the cap 12 are provided. A structure in which a brazing material is held between the edges of the mold is adopted. This embodiment has a large degree of freedom with respect to the positional displacement in the horizontal direction as well as the positional displacement in the vertical direction. The sealing step of this embodiment is performed by combining the L-shaped annular member and the L-shaped edge portion of the cap 12 and then fixing the L-shaped annular member to the hermetically sealed container base 11.

(Ninth Embodiment) (See FIG. 3 (H)) In this embodiment, as the stress relaxation mechanism 20, a groove having an inclined surface formed in the hermetically sealed container base 11 and the cap 1 are used.
The structure in which the brazing material is held in the groove is adopted by combining edge portions inclined in the same direction as the inclined surface of the second cylindrical groove. This embodiment has a large degree of freedom with respect to the positional displacement in the horizontal direction as well as the positional displacement in the vertical direction.

[0032]

As described above, according to the present invention,
A step of brazing the back surface of the electronic component and the bottom surface of the cap to the outside to radiate heat generated by the electronic component such as a semiconductor chip fixed by the TAB method to the airtight sealed container base; If the brazing process for hermetically sealing the edge of the hermetically sealed container base and the cap is performed in the same step, distortion and residual stress harmful to the quality of electronic parts such as semiconductor chips and the hermetically sealed container base It is possible to provide a hermetically sealed container for electronic components that does not leave any of the above, and it is expected to contribute greatly to the technical field of hermetically sealing various electronic components.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a hermetically sealed container for electronic parts according to a first embodiment.

2A to 2D are configuration explanatory views (1) of a stress relaxation mechanism of another embodiment.

3 (E) to (H) are configuration explanatory views (2) of a stress relaxation mechanism of another embodiment.

FIG. 4A to FIG. 4C are explanatory views of a sealing process of a conventional hermetically sealed container for electronic components.

[Explanation of symbols]

 1, 11 Airtight sealed container base 2 Connection pin 3 TAB inner lead 4 Semiconductor chip 5 Connection bump 6, 12 Cap 7 Brazing material 8 Metallization layer 9, 13 to 20 Stress relaxation mechanism 10 Brazing material

Claims (7)

[Claims] 1. An airtight seal for electronic parts, characterized in that a portion for hermetically sealing a hermetically sealed container base body and a cap with a brazing material is provided with a mechanism for relieving stress generated when the hermetically seal is performed. Stop container. 2. A hermetically sealed container base, a cap formed on the hermetically sealed container base, an annular body formed on the hermetically sealed container base, and a shape in which an edge portion conforms to a side portion of the annular body. 2. The hermetically sealed container for electronic parts according to claim 1, further comprising: and an annular body and an edge portion of the cap are fixed to each other by a brazing material. 3. A hermetically sealed container substrate, an annular body formed on the hermetically sealed container substrate and provided with a groove, and an edge portion having a shape adapted to fit in the groove of the annular body. The hermetically sealed container for electronic parts according to claim 1, further comprising: a cap, wherein an edge portion of the cap is inserted into a groove of the annular body and is fixed by a brazing material. 4. The hermetically sealed container for electronic parts according to claim 2, wherein the annular body is fixed on the hermetically sealed container base by a brazing material. 5. A hermetically sealed container base body, an annular body formed on the hermetically sealed container base body, and a cap of the hermetically sealed container base body provided with a groove conforming to the shape of the annular body at an edge portion. 2. The hermetically sealed container for electronic parts according to claim 1, further comprising: an annular body inserted into a groove of the cap and fixed by a brazing material. 6. A hermetically sealed container base, a groove formed in the hermetically sealed container base, and a cap of the hermetically sealed container base having an edge portion having a shape conforming to the groove. The hermetically sealed container for electronic parts according to claim 1, wherein an edge portion of the cap is inserted into the groove and fixed by a brazing material. 7. A hermetically sealed container substrate and a cap are hermetically sealed with a brazing material at a portion where the brazing material is melted to perform the hermetic sealing, and an edge portion of the cap has the hermetically sealed container substrate. A mechanism for preventing contact with the airtight seal is provided to relieve stress generated between the base and the cap of the hermetically sealed container during solidification of the brazing filler metal. How to stop.