JPH1050768A - Package for housing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device housing package capable of electrically connecting each electrode of a semiconductor device put inside to a predetermined external electric circuit stably for over a long period of time. SOLUTION: This package comprises an insulating base substance 1 made out of electrical insulating material and having a semiconductor device 3 mount section 1a on the top surface and a large number of recession 1b in the underside, a plurality of metalized wiring layers 5 led out from the periphery of the mount section 1a over to the bottoms of the recessions 1b, a plurality of connecting pads 6 formed in the recessions 1b and having arcshaped dents in the underside, and terminals 7 having approximately spherical projecting parts 7b on the underside of the insulating base substance 1. The generation of a fatigue failure caused by thermal stress of the junction between the connecting pads 6 and the terminals 7 is prevented, by causing a semiconductor device mount package to satisfy conditional expressions of 1.0<R/r<=9.0, and R>=(r<2> +d<2> )/2d, when the radius of curvature of the arcshaped dent of each connecting pad 6 is represented by R, and the radius and the depth of each recession 1b are represented by (r) and (d) respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device housing package for housing a semiconductor device such as a semiconductor integrated circuit device.

[0002]

2. Description of the Related Art Conventionally, a semiconductor element housing package for housing a semiconductor element such as an LSI (large-scale integrated circuit element) is generally made of an electrically insulating material such as alumina ceramics, and has a semiconductor element substantially at the center of its upper surface. An insulating substrate having a mounting portion for mounting and housing the same, and a plurality of metallized wiring layers made of a refractory metal powder such as tungsten and molybdenum drawn out from around the mounting portion to the lower surface of the insulating substrate. A plurality of connection pads formed on the lower surface of the insulating base and electrically connected to the metallized wiring layer, a substantially spherical terminal made of solder or the like brazed and attached to the connection pad; And a lid for sealing. The semiconductor element is adhered and fixed to the bottom surface of the mounting portion of the insulating base via an adhesive made of glass, resin, or the like. And the metallized wiring layer are electrically connected via bonding wires, and the lid is joined to the upper surface of the insulating base via a sealing material made of glass, resin, or the like, so that the inside of the container including the insulating base and the lid is connected. A semiconductor device as a product is obtained by hermetically sealing a semiconductor element.

In such a semiconductor device, a substantially spherical terminal made of solder or the like brazed to a connection pad on the lower surface of an insulating base is connected to a wiring conductor of an external electric circuit board formed of a resin insulating material and copper wiring. Then, the substantially spherical terminal is heated and melted at a temperature of about 150 to 250 ° C., and the terminal is bonded to a wiring conductor, thereby mounting the terminal on an external electric circuit board. At the same time, each electrode of the semiconductor element housed in the semiconductor element housing package is connected to an external electric circuit via the metallized wiring layer and the substantially spherical terminal.

[0004]

However, in this conventional package for housing a semiconductor element, the thermal expansion coefficient of the insulating base made of alumina ceramics or the like is 4-6.
In contrast to about 5 × 10 ⁻⁶ / ° C., the external electric circuit board is generally made of a resin insulating material such as glass epoxy and has a large thermal expansion coefficient of 1 × 10 ⁻⁵ to 4 × 10 ⁻⁵ / ° C. And the thermal expansion coefficients of the two were greatly different. Therefore, when a temperature cycle associated with the semiconductor element generating heat during operation and returning to the ambient temperature when stopped is repeatedly applied to both the insulating base of the semiconductor element storage package and the external electric circuit board,
A large thermal stress is generated between the two due to the difference in the coefficient of thermal expansion, which also acts between the connection pad and the substantially spherical terminal, causing fatigue at these joints, and eventually causing peeling or destruction. As a result, each electrode of the semiconductor element housed inside the semiconductor element housing package cannot be electrically connected to a predetermined external electric circuit board for a long period of time. .

The present invention has been devised in view of the above problems, and has as its object to operate a semiconductor device at a joint between a connection pad formed on a semiconductor device housing package and a substantially spherical terminal. Provided is a semiconductor element housing package that can stably and electrically connect each electrode of a semiconductor element housed therein to a predetermined external electric circuit for a long period of time by preventing the occurrence of fatigue fracture due to accompanying heat generation. Is to do.

[0006]

According to the present invention, there is provided a package for housing a semiconductor element, which is made of an electrically insulating material, has a mounting portion on which an upper surface of a semiconductor element is mounted, an insulating base having a plurality of concave portions on a lower surface, A plurality of metallized wiring layers extending from the periphery of the mounting portion to the bottom surface of the concave portion of the insulating base; and a plurality of connection pads formed in the concave portion and electrically connected to the metallized wiring layer. And a terminal joined to the connection pad and having a terminal having a substantially spherical protrusion on the lower surface of the insulating base, wherein the connection pad has an arc-shaped recess on the lower surface thereof. When the radius of curvature of the arc-shaped depression is R, the radius of the depression is r, and the depth of the depression is d, the following conditional expression is satisfied.

1.0 <R / r ≦ 9.0 R ≧ (r ² + d ² ) / 2d.

According to the semiconductor device housing package of the present invention, a connection pad having an arc-shaped depression on the lower surface is provided in a concave portion on the lower surface of the insulating base, and a terminal having a substantially spherical projection on the lower surface of the insulating base is provided. When joining to the connection pad, and the radius of curvature of the arc-shaped joint with the terminal of the connection pad is R, the radius of the recess is r, and the depth of the recess is d,
Since 1.0 <R / r ≦ 9.0 and R ≧ (r ² + d ² ) / 2d are satisfied, the semiconductor element is housed inside the semiconductor element housing package and the external electric circuit board is mounted. When mounted, heat generated during operation of the semiconductor element is repeatedly applied to both the insulating substrate and the external electric circuit board, and a large thermal stress caused by a difference in thermal expansion coefficient between the two is formed in the semiconductor element housing package. Even if it is added to the joint between the pad and the almost spherical terminal, it is possible to secure a sufficient joint area between the connection pad having the arc-shaped depression and the almost spherical terminal, and to join them together firmly Therefore, peeling and fatigue failure do not easily occur, and as a result, each electrode of the semiconductor element housed in the semiconductor element housing package is kept at a predetermined level for a long period of time. It is possible to stably and electrically connect to the external electric circuit board.

In addition, since the alloy layer having low strength is distributed in a hemispherical shape at the joint between the connection pad having the arc-shaped depression and the substantially spherical terminal, the joint is formed by cracks traveling along the alloy layer. Since the process until the part is broken becomes longer and the time until the part is broken becomes longer, each electrode of the semiconductor element housed in the semiconductor element housing package can be also used for a long period of time in a predetermined external electric circuit. It is possible to stably and electrically connect to the substrate.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of a package for housing a semiconductor element according to the present invention, and FIG. 2 is an enlarged sectional view of a main part thereof. In these figures, 1 is an insulating base, 2 is a lid, and 3 is a semiconductor element. The insulating base 1 and the lid 2 constitute a container 4 for housing the semiconductor element 3.

The insulating base 1 is provided with a mounting portion 1a in which the semiconductor element 3 is mounted at substantially the center of the upper surface thereof, and the semiconductor element 3 is provided on the bottom surface of the mounting portion 1a with glass, resin or the like. Attached via an adhesive.

The insulating substrate 1 is made of an electrically insulating material such as ceramics having a small coefficient of thermal expansion, for example, a sintered body of aluminum oxide, a sintered body of aluminum nitride, a sintered body of silicon carbide, a sintered body of mullite, a sintered body of glass ceramic. It is made of a sintered body, for example, when it is made of an aluminum oxide sintered body,
A suitable organic binder, a plasticizer, a solvent, etc. are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. to form a slurry, and the green sheet is formed from the slurry by a doctor blade method or a calendar roll method. (Green sheet). Thereafter, the green sheet is appropriately punched, a plurality of the green sheets are laminated, and the green sheet is fired at a temperature of about 1600 ° C.

Reference numeral 5 denotes a metallized wiring layer, on which a plurality of metallized wiring layers 5 are formed from the periphery of the mounting portion 1a on which the semiconductor element 3 is mounted and accommodated to the lower surface of the insulating base 1.

Further, reference numeral 1b denotes a plurality of concave portions formed on the lower surface of the insulating base 1. Inside the concave portion 1b, an arc-shaped concave portion on the lower surface to which the metallized wiring layer 5 is electrically connected is provided. A plurality of connection pads 6 are formed.

The metallized wiring layer 5 is made of a metal having a high melting point such as tungsten, molybdenum and manganese.
A metal paste obtained by adding and mixing a solvent or the like is preliminarily printed and applied in a predetermined pattern on a green sheet serving as the insulating substrate 1 by a conventionally known screen printing method or the like. It is formed on the pattern.

The connection pads 6 are also formed on the metallized wiring layer 5.
A metal paste made of a high melting point metal such as tungsten, molybdenum, manganese or the like and obtained by adding a suitable organic binder, plasticizer, solvent, etc. to a high melting point metal powder such as tungsten is mixed with the concave portion 1b of the insulating base 1. After a predetermined amount is filled, the organic binder and the solvent are evaporated and then fired to form an arc-shaped depression on the lower surface, and the upper surface is electrically connected to the metallized wiring layer 5.

When a metal paste is poured by screen printing after laminating a green sheet having a hole serving as the concave portion 1b, the surface shape of the connection pad 6 becomes an arc-shaped depression due to the surface tension of the metal paste. By firing this, an arc-shaped depression having a desired radius of curvature can be formed.

The surface of the arc-shaped refractory metal formed as described above is preferably plated with nickel having a thickness of 1 to 20 μm and gold plating having a thickness of 0.01 to 0.5 μm. Oxidation of the surface can be effectively prevented, and at the same time, the bonding with the substantially spherical terminal 7 made of solder or the like can be firmly maintained.

The metallized wiring layer 5 functions to electrically connect each electrode of the semiconductor element 3 to a substantially spherical terminal 7 joined to the connection pad 6, and the mounting portion 1 of the insulating base 1
Each electrode of the semiconductor element 3 is electrically connected to a region located in the vicinity of a through a bonding wire 8.

The connection pad 6 electrically connected to the metallized wiring layer 5 also functions as a base metal layer when the substantially spherical terminal 7 is attached to the insulating base 1, and the connection pad 6 has an arcuate shape. A part of a substantially spherical terminal 7 made of, for example, a low-melting-point lead-tin solder having a weight ratio of lead and tin of 6: 4 is formed on the surface of the concave surface of the connection pad 6. And a joining portion 7a having such a shape as to be combined with, for example, brazing.

The terminal 7 joined to the connection pad 6
The lower surface of the insulating base 1 has a spherical projection 7b, and the spherical projection 7b connects the terminal 7 to the external electric circuit board 9.
When it is connected to the wiring conductor 10 described above, the connection conductor 10 acts to make the connection easy and reliable.

In the package for accommodating a semiconductor element of the present invention, the radius of curvature of the junction formed by the arc-shaped depression of the connection pad 6 with the substantially spherical terminal 7 is R, the radius of the recess 1b is r, and the depth of the recess 1b is When d is 1.0, R <r
≦ 9.0 and R ≧ (r ² + d ² ) / 2d, whereby the connection pad 6 and the substantially spherical terminal 7 are firmly combined with a sufficient joint area. The semiconductor element 3 is accommodated in the mounting portion 1a of the insulating base 1, and the external electric circuit board 9
After the semiconductor element 3 is mounted, heat generated during operation of the semiconductor element 3 is repeatedly applied to both the insulating base 1 and the external electric circuit board 9, and a large thermal stress resulting from a difference in the coefficient of thermal expansion between the two is applied to the arc-shaped connection pad 6. Even when it is applied to the joint between the connection pad 6 and the substantially spherical terminal 7, the peeling and fatigue damage between the connection pad 6 and the substantially spherical terminal 7 are effectively prevented.

In FIG. 2, the diameter of the recess 1b is 2
r (radius r × 2).

If R / r is 1.0 or less (R / r ≦ 1.0) with respect to the above conditional expression, a joint surface between the connection pad 6 of the concave portion 1b and the joint 7a of the substantially spherical terminal 7 is formed. At the inflection point A, the angle formed by the tangent of the lower surface of the insulating base 1 and the joint 7a is nearly 90 °, so that the thermal stress accompanying the heat generation of the semiconductor element 3 tends to concentrate at the inflection point, and the thermal stress repeats. This tends to easily cause peeling or fatigue failure between the connection pad 6 and the substantially spherical terminal 7.

On the other hand, R / r exceeds 9.0 (9.0 <R /
r) and the lower surface of the connection pad 6 become substantially flat and not sufficiently arcuate, so that the connection pad 6 and the terminal 7
Insufficient bonding area is required, and thermal stress is all received on this flat bonding surface, and peeling and fatigue failure tend to occur.

When R becomes smaller than (r ² + d ² ) / 2d (R <(r ² + d ² ) / 2d), the connection pad 6
The central portion of the arc-shaped depression is flattened by the bottom surface of the concave portion 1b into a flat shape, and a bending point is formed at a portion where the flat surface and the arc of the surrounding depression contact each other. There is a tendency that stress is concentrated and peeling and fatigue fracture are likely to occur.

Thus, according to the package for accommodating a semiconductor element of the present invention, the semiconductor element 3 is bonded and fixed to the bottom of the mounting portion 1a of the insulating base 1 with an adhesive, and each electrode of the semiconductor element 3 is connected to the metallized wiring layer 5 Is electrically connected via a bonding wire 8, and then the lid 2 is joined to the upper surface of the insulating base 1 with a sealing material made of glass, resin, or the like, and a container including the insulating base 1 and the lid 2 is formed. A semiconductor device as a product is obtained by hermetically sealing the semiconductor element 3 inside 4.

[0028]

EXAMPLES Specific examples of the present invention will be described below. A ceramic green sheet mainly made of alumina is subjected to a recess 1b and a hole to be a metallized wiring layer 5, screen printing and punching of a metal paste, and a plurality of these are laminated and fired at a temperature of about 1600 ° C. On a lower surface of an insulating base having an outer size of 35 mm square and a thickness of 1 mm, concave portions 1 b having a radius r of 0.27 mm and a depth d of 0.2 mm are formed in a lattice pattern of 1 mm pitch.
Eighty pieces were produced.

Next, a tungsten paste is screen-printed in the concave portion 1b, and after baking, nickel plating having a thickness of 2 to 3 μm and gold plating having a thickness of 0.2 to 0.3 μm are applied to form arc-shaped depressions having various curvature radii R. The connection pad 6 was formed. Then, approximately spherical terminals 7 made of solder are joined to the surfaces of the connection pads 6 to form connection pads 6.
And semiconductor element housing package samples A to H in which the radius of curvature R at the junction with the substantially spherical terminal 7 was changed. Further, as a sample of the comparative example, a sample in which the surface of the connection pad 6 was made the same flat surface as the lower surface of the insulating base 1 was also manufactured.
I got

The samples A to I obtained as described above were prepared with a thickness of 1.6
-4 ℃ and + 125 ℃ mounted on the wiring conductor of the external electric circuit board consisting of FR4
The temperature cycle test was performed to determine the number of temperature cycles until the joint portion was broken, and the joining life between the semiconductor device housing package and the external electric circuit board was evaluated.

Table 1 shows the results. In the column of R pair (r ² + d ² ) / 2d in Table 1, R <, R =, and R ≧ mean that R <(r ² + d ² ) / 2d and R =
(R ² + d ² ) / 2d, and R ≧ (r ² + d ² ) / 2d.

[0032]

[Table 1]

From the results in Table 1, it is found that 1.0 <R / r ≦ 9.0, R
Samples B to satisfy each conditional expression of ≧ (r ² + d ² ) / 2d
In G, the number of temperature cycles leading to fracture is at least 950 or more, and in Samples A and H which do not satisfy the above conditional expression, at most 500 cycles, and in Sample I having a flat connection pad surface, only 100 cycles. It can be seen that the bonding life is very good with respect to.

Next, similarly, the depth d of the concave portion 1b is set to 0.3.
mm, connection pads 6 having arc-shaped depressions having various curvature radii R were formed, and substantially spherical terminals 7 were joined to obtain semiconductor element storage package samples J to Q. Further, a sample in which the surface of the connection pad 6 had a flat surface was also manufactured, and a sample R was obtained.

Table 2 shows the results of the same temperature cycle test as described above and the evaluation of the bonding life.

[0036]

[Table 2]

From the results in Table 2, it can be seen that 1.0 <R / r ≦ 9.0,
Sample J that satisfies each condition of R ≧ (r ² + d ² ) / 2d
ＰP, the number of temperature cycles leading to fracture is at least 1000 cycles or more. Sample Q, which does not satisfy the above conditional expression, has at most 300 cycles, and sample R, which has a flat connection pad surface, has only 100 cycles. It can be seen that the bonding life is very good.

According to these results, according to the semiconductor device housing package of the present invention, each electrode of the semiconductor device housed therein can be stably electrically connected to a predetermined external electric circuit board for a long period of time. Was confirmed.

[0039]

According to the package for housing a semiconductor element of the present invention, an insulating base made of an electrically insulating material and having a mounting portion on the upper surface on which the semiconductor element is mounted, a plurality of concave portions on the lower surface, and the insulating base. A plurality of metallized wiring layers led from the periphery of the mounting portion to the bottom surface of the concave portion and electrically connected to the metallized wiring layer, and formed in the concave portion so as to have an arc-shaped concave portion on the lower surface. What is claimed is: 1. A semiconductor device housing package comprising: a plurality of connection pads; and a terminal joined to the connection pads and having a substantially spherical protrusion on a lower surface of the insulating base, wherein a curvature of an arc-shaped recess of the connection pads is provided. When the radius is R, the radius of the concave portion is r, and the depth of the concave portion is d, 1.0 <R / r ≦ 9.0, R ≧ (r ² + d)
² ) / 2d, the substantially spherical terminal can be firmly bonded to the connection pad having the arc-shaped depression, and the semiconductor device is housed inside the semiconductor element housing package. When the element is housed and mounted on an external electric circuit board, heat generated during operation of the semiconductor element is repeatedly applied to both the insulating substrate and the external electric circuit board, and a large thermal stress caused by a difference in thermal expansion coefficient between the two. Even if it is added to the joint between the connection pad formed on the semiconductor element housing package and the substantially spherical terminal, the bonding area between the arc-shaped connection pad and the substantially spherical terminal can be sufficiently secured, and Are firmly combined and joined, so that peeling or fatigue failure does not easily occur, and as a result, the semiconductor device is housed inside the semiconductor device housing package. It is possible to electrically connect the electrodes of the conductive elements stably over a long period of time to a predetermined external electric circuit board.

Therefore, according to the semiconductor element housing package of the present invention, the occurrence of fatigue destruction due to the heat generated by the operation of the semiconductor element at the junction between the connection pad formed on the semiconductor element housing package and the substantially spherical terminal. Thus, it is possible to provide a semiconductor element housing package that can stably and electrically connect each electrode of a semiconductor element housed therein to a predetermined external electric circuit for a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a package for housing a semiconductor element of the present invention.

2 is an enlarged cross-sectional view of a main part of the package for housing a semiconductor element shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 1a ... Placement part 1b ... Concave part 2 ... Lid 3 ... Semiconductor element 5 ... Metallized wiring layer 6 ...・ Connection pad 7 ・ ・ ・ ・ ・ ・ ・ Terminal 7b ・ ・ ・ Almost spherical projection

Claims (1)

[Claims] 1. A mounting portion made of an electrically insulating material, on which a semiconductor element is mounted on an upper surface, an insulating substrate having a plurality of concave portions on a lower surface, and a portion extending from the periphery of the insulating portion to the bottom surface of the concave portion. A plurality of metallized wiring layers to be led out, a plurality of connection pads formed in the recesses and electrically connected to the metallized wiring layer, and joined to the connection pads, on a lower surface of the insulating base. A terminal having a substantially spherical protrusion, wherein the connection pad has an arc-shaped depression on the lower surface thereof,
The radius of curvature of the arc-shaped recess is R, the radius of the recess is r,
A semiconductor element storage package characterized by satisfying the following conditional expression when the depth of the concave portion is d. 1.0 <R / r ≦ 9.0 R ≧ (r ² + d ² ) / 2d