JP3327450B2 - Package for electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package for an electronic component used for sealing an electronic component such as an integrated circuit chip, and more particularly, to a package for an electronic component having a heat radiating member (heat sink) fixed to a ceramic package body. It relates to a package (hereinafter, also simply referred to as “package”).

[0002]

2. Description of the Related Art A ceramic package having a heat dissipating member, which is called a heat slug type in which electronic components such as an integrated circuit chip (hereinafter, also simply referred to as an integrated circuit chip) are fixed (joined) to the heat dissipating member, is known. , A package body and a heat radiating member. 6 to 8 show an example of the heat slug type package 61. FIG. This is a package body (hereinafter, simply referred to as a body) 6
The inside of the formation site 64 of the second bonding pad (only part of which is shown) penetrates (opens) vertically (from the upper surface to the lower surface), and the through hole 65 is provided with the lower surface 66 of the main body 62.
A heat dissipating member 81 having a stepped shape (longitudinal cross section) is inserted from its side with its upper step 82 fitted in a gap, and the upper surface (shoulder surface) 84 of the lower step 83 is attached to the lower surface 66 of the main body 62 by the brazing material 67. It has a brazed configuration.

[0003] The package 61 thus configured is
The upper surface of the upper portion 82 of the heat dissipating member 81 forms a die attach surface (a portion to which the integrated circuit chip is fixed) 85, and the die attach surface 85 and the upper portion of the inner surface 68 of the through hole 65 of the main body 62 form a die. Make up the touch cavity. In the package body 62, the peripheral surface of the through hole 65 in the lower surface 66, which is a surface to be brazed to the heat radiating member 81, is W
(Tungsten) or Mo (Molybdenum) metallized with Ni (nickel) plating on it,
The heat radiating member 81 is made of Ni-plated Cu-W (copper tungsten) or the like.

By the way, such a package 61 is
After the heat dissipating member 81 is integrated by brazing, the die attach surface (part) 85 of the heat dissipating member 81 is used for corrosion prevention and the like.
And the external heat dissipation surface and the bonding pad 6 of the main body 62
3. Ni plating and Au (gold) plating are applied to input / output terminals (not shown) such as pins. On the other hand, since the upper portion 82 of the heat radiating member 81 is gap-fitted in the through hole 65 of the package body 62, between the inner surface 68 of the through hole 65 and the outer surface 86 of the upper portion 82 of the heat radiating member 81. As shown in the figure, a groove-shaped gap (gap) S having a predetermined width W and a closed back portion can be formed in a frame shape in a plan view (as viewed from above). For S, the cleaning liquid is unlikely to reflux in the cleaning step of the plating liquid after plating. This is because the width W of the gap S is small and the cleaning liquid can enter and exit only from the opening side (on the illustration) of the gap S. Therefore, in the above-described conventional package, the plating solution remains in the gap S. There was a problem that it was easy.

If the plating solution remains in the gap S, the plating on the surface touched by the plating solution is altered or discolored, and such alteration is diffused to the die attach surface 85 and the like, and the appearance of the package 61 is reduced. Failure to do so. Further, after the integrated circuit chip 91 is fixed to the die attach surface 85 by brazing as shown by a two-dot chain line in the figure, the performance of the integrated circuit chip 91 and the life of the integrated circuit chip 91 are reduced. This can cause problems.

[0006]

In order to prevent such a problem from occurring, that is, to prevent the plating solution from remaining in the gap S, the gap S has a predetermined width which does not hinder the reflux of the cleaning solution. W (normally about 0.25 mm on one side)
, Which has been a factor in preventing the package 61 from being downsized.

The larger the gap S, the more the bonding pad 63 of the package 61 and the integrated circuit chip 91
And the distance between the input and output terminals (electrodes) becomes longer, and the bonding wire (hereinafter, also simply referred to as a wire) 92 becomes longer. Then, as the length becomes longer, the adjacent wires are more likely to come into contact with each other due to slack or the like, or a problem such as an increase in inductance of the wires occurs.

Further, if there is a lateral displacement when the heat radiating member 81 is inserted and fixed, the width W of the gap S forming the opposite side will be large or small. On the side where the gap is small, a problem will occur in the recirculation of the cleaning liquid. On the side where the gap is large, the above-mentioned problem due to the longer bonding wire becomes more pronounced. As understood from this, the width W of the gap S is
As long as there is no problem with the recirculation of the cleaning solution for the plating solution cleaning process, the smaller the size, the better.

The present invention has been made in view of such a point in a heat slug type package provided with a heat radiating member. An object of the present invention is to prevent a plating solution from remaining in the gap. The purpose of the present invention is to reduce the width of the gap as much as possible without affecting the reflux of the cleaning liquid.

[0010]

According to a first aspect of the present invention, there is provided a heat radiation member having a stepped shape formed in a through hole vertically penetrating a package body. A package for an electronic component having a part inserted from below the package body in a clearance-fitted state .
After the heat member is integrated with the package body, Ni plating is performed.
In the case where gold and Au plating are applied, the inner surface of the through hole extends from the upper edge (opening) to the lower edge side of the through hole.
The width of the gap is locally increased by forming a concave groove . The present invention described in claim 2 is a package
Formed in a stepped shape through through holes that penetrate the top and bottom of the
Of the upper heat sink is below the package body.
For electronic components inserted in a gap-fitted state
Wherein the heat radiation member is integrated with the package body.
Smell after plating with Ni and Au
Between the inner surface of the through hole and the outer surface of the upper section.
In the gap, a ring of the cleaning solution in the cleaning of the plating solution after plating is provided.
In order to facilitate the flow, the through hole is provided on the inner surface of the through hole.
Forming a concave groove extending from the upper edge to the lower edge to form the width of the gap
Is locally expanded. Further, claim 3
The present invention described in (1), the penetrating through the package body
In the through hole, a stepped radiating member
It is inserted in a clearance fit state from below the package body,
Before the metallization layer on the lower surface side of the package body
The electronic part with the upper surface of the lower part of the heat dissipation member brazed
An article package, wherein the heat radiating member is the package.
After being integrated with the main body, Ni plating and Au plating are applied.
In shall, outside of the upper portion and the inner surface of the through hole
In the gap made with the side surface, wash the plating solution after plating.
In order to facilitate the reflux of the cleaning solution,
Forming a groove extending from the upper edge to the lower edge of the through hole;
The width of the gap is locally widened. Departure
In the description, the shape of the concave groove in plan view or its cross-sectional shape is an arc shape or a similar shape (for example, a U-groove shape).
It is preferable because the production is easy.

In the above-mentioned means, since there is a concave groove opening at the upper edge of the through-hole, the gap is locally large at a portion where the concave groove exists. Therefore, the cleaning liquid can not only enter and exit from the upper part (upper edge opening) of the gap, but also easily enter the depth (groove bottom side of the gap) from the locally wide groove, and extend to the side of the depth of the groove. It is designed to be able to get in and out of the gap from the side (horizontal) and to easily recirculate into the gap. It is preferable that the concave groove in the present invention extends to the lower edge of the through hole so that the cleaning liquid easily enters the groove bottom side of the gap. It is preferable that the concave groove is formed along the up and down direction of the through hole in terms of the circulation of the cleaning liquid and the production. However, the groove may be inclined.

That is, in the present invention, since the cleaning liquid easily flows through the gap due to the presence of the concave groove, the gap can be reduced without leaving the plating solution. Therefore, the size of the package can be reduced as much as the gap can be reduced, the distance between the bonding pad of the package and the input / output terminal of the integrated circuit chip can be shortened, and the bonding wire can be shortened. .

In the above means, when the inner side surface of the through hole and the outer side surface (die attach cavity) of the upper portion are substantially square in plan view, at least the concave groove is formed in the through hole. It is preferable that the cleaning liquid is formed substantially at the center of each side of the square on the inner surface (a total of four places) to recirculate the cleaning liquid into the gap. Here, “at least” means that an additional portion may be provided on each side depending on the length of one side of the through hole in plan view, the opening width of the concave groove, and the like. A range (position or number) that does not affect the formation position of the bonding pad corresponding to the input / output terminal of the integrated circuit chip
May be appropriately designed. And in the above means,
The inner surface of the through hole and the outer surface of the upper step are viewed in plan,
In the case where each of the through-holes is substantially square, the concave groove may be formed at least at each corner of the square on the inner surface of the through hole (a total of four corners). Here, “at least” means that, as described above, depending on the length of one side in plan view, the opening width of the concave groove, and the like, it may be further provided on each side.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are shown in FIGS.
This will be described in detail with reference to FIG. In the figure, reference numeral 1 denotes a heat slug type package of the present embodiment, which is mainly constituted by a ceramic package body 2 and a heat radiation member 21 as follows. That is, although not shown in detail, the ceramic package body 2 is formed in a substantially square thin plate shape by laminating a plurality of predetermined green sheets, thermocompression bonding, and firing. A forming surface 4 of a bonding pad (only part of which is shown) is formed in a frame shape and recessed in a plan view, and a through hole 5 is formed in the inside thereof so as to penetrate (open) vertically (upper surface to lower surface) in a substantially square shape. Have been. In the present example, a concave groove 7 is formed above the through-hole 5 in a semi-circular shape at the approximate center of each side forming the inner side surface (inner wall surface) 6 of the through-hole 5 of the main body 2 in plan view. Edge (opening)
It is formed along the up-down direction from 5a to lower edge 5b. Note that a W metallized layer having a predetermined width is formed on the peripheral surface of the opening of the through hole 5 on the lower surface 8 side of the main body 2 by simultaneous firing with the main body 2, and the surface thereof is plated with Ni.

On the other hand, the heat dissipating member 21 is made of copper tungsten in this embodiment, and has a lower step portion 22 having a substantially square plate shape larger than the planar shape of the inner side surface 6 of the through hole 5 of the main body 2. The upper section 23 is formed in a convex shape in cross section, and is entirely plated with Ni. The upper portion 23 has a substantially square plate shape slightly smaller than the planar shape of the inner surface 6 of the through hole 5.

In this embodiment, however, the heat radiating member 21 is inserted into the through hole 5 of the main body 2 from the lower surface 8 side thereof with the upper step 23 fitted in the gap, is positioned at the center thereof, and is positioned at the center thereof. The (shoulder surface) 24 is fixed to the Ni-plated W metallized layer on the lower surface 8 side of the main body 2 by soldering via a silver solder 25. The upper surface of the upper portion 23 of the heat dissipating member 21 forms a die attach surface 26, and a die attach cavity is formed by the die attach surface 26 and an upper portion of the inner surface 6 of the through hole 5.

The package 1 of the present embodiment thus formed
, A gap S having a width W exists between the outer side surface 27 of the upper portion 23 of the heat radiation member 21 and the inner side surface 6 of the through hole 5 of the package body 2. The width of the gap S is locally increased at the concave groove 7 formed in the inner side surface 6 of the through hole 5 in the gap S. The width S of the gap S in the present example has a conventional design standard value (for example, 0.
25 mm) or less (0.1 mm), and the concave groove 7 has a semicircular arc shape with a radius of 0.3 m.
m, so that the gap S is set to be 0.4 mm at the maximum at the concave groove 7.

In the package 1 of the present embodiment, after the main body 2 and the heat radiating member 21 are integrated as described above, the die attach surface 26 of the heat radiating member 21 and the external heat radiating surface etc. Is subjected to Ni plating and Au plating. Then, it is immersed in a cleaning liquid tank for cleaning the plating liquid.
At that time, the cleaning liquid can not only enter and exit the gap S from above, but also as shown by the arrow in FIG.
From the bottom (the groove bottom side of the gap S), so that it is easy to get in and out.
Can enter and leave the gap S. That is, in the present example, the cleaning liquid is easily circulated through the gap S by the presence of the concave groove 7, and therefore, even if the width W of the gap S is small, the plating liquid can be efficiently cleaned. Moreover, in this example,
Since the concave groove 7 is located at the center of each side, the distance at which the cleaning liquid circulates to the left and right corners 9 is the same, and therefore, the cleaning is performed substantially equally on the left and right sides.

As described above, in this embodiment, the width W of the gap S is
Even if is small, the concave groove 7 is formed at the center of each side of the through hole 5, so that the cleaning liquid or the like can flow into the gap S from both sides of the concave groove 7 or into the concave groove 7 from the gap S. .
That is, the provision of the concave groove 7 allows the cleaning liquid to pass through the gap S.
Is easily circulated, the width W of the gap S can be reduced. As a result, the size of the package 1 can be reduced accordingly. Further, although not shown, when the integrated circuit chip is wire-bonded after being fixed to the die-attached surface by brazing (Au-Sn or the like), the width W of the gap S is smaller than that of the package body. The distance between the second bonding pad 3 and the input / output terminal of the integrated circuit chip is shortened, so that the bonding wire can be shortened.

FIG. 5 shows another example of the embodiment of the present invention. However, in the previous example, the die attach cavity was substantially square when viewed from above, and the concave groove was provided at one location (a total of four locations) substantially at the center of each side of the inner surface of the through hole. On the other hand, in this example, only the point where the concave groove 37 is provided at the four corners of the through hole 5 at one corner (a total of four places) in a plan view, substantially 3/4 arc is provided. Is different from the previous example only, and since its operation and effect are basically common to the previous example, the same portions are denoted by the same reference numerals and description thereof will be omitted. In this example, since the concave groove 37 is located at all corners (four corners), even if the corner of the heat radiating member 21 is small as shown in the figure, the upper step 23 is connected to the through hole 5 of the package body 2. This has the effect of being easy to insert into

The shape of the concave groove in plan view or its cross-sectional shape in the present invention is not limited to an arc shape or a U-shape, but may be an appropriate shape in consideration of the ease of circulation of the cleaning liquid. And it is sufficient. The size (cross-sectional area), formation position, or number of the concave grooves may be appropriately designed according to the design of the input / output terminals of the integrated circuit chip to be mounted and in consideration of the width of the gap. Further, the electronic component package according to the present invention can be widely applied to various ceramic electronic component packages such as PGA (pin grid array), LGA (land grid array), and chip carriers.

[0022]

As is apparent from the above description, according to the package of the present invention, a concave groove extending from the upper edge to the lower edge of the through hole is provided on the inner surface of the through hole of the package body. When the plating solution is cleaned after plating, even if the gap between the inner surface and the outer surface of the upper portion of the heat radiating member is small, the circulation of the cleaning solution in the gap becomes easy. That is, in the present invention, since the cleaning liquid easily flows around the gap due to the presence of the concave groove, the gap can be reduced without leaving the plating solution. Therefore, since the gap can be reduced, it is effective in reducing the size of the package and the bonding wire.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of an embodiment embodying a package according to the present invention as viewed from a die attach surface side (upper side).

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially enlarged view of FIG. 2;

FIG. 4 is a partial perspective view for explaining a state in which the cleaning liquid flows around the gap when the plating liquid is cleaned.

FIG. 5 is an explanatory plan view of another embodiment embodying the package according to the present invention as viewed from the die attach surface side (upper side).

FIG. 6 is a sectional view showing an example of a conventional heat slug type package.

FIG. 7 shows the package of FIG.
FIG.

FIG. 8 is a partially enlarged view of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Package 2 Main body 5 Through-hole 5a Upper edge of through-hole 5b Lower edge of through-hole 6 Inner surface of through-hole 7, 37 Groove 21 Heat-dissipating member 23 Upper portion of heat-dissipating member 27 Outer surface of upper portion S Gap

Claims (5)

(57) [Claims] An electronic component package in which a stepped heat radiating member is inserted into a through hole vertically penetrating a package body from above the package body with a gap fitted from below the package body. The heat dissipating member is
After being integrated with the cage body, Ni plating and Au plating
In those applied to the inside surface of the through hole, and wherein the <br/> locally unfolded to the width of the gap to form a groove extending lower edge side from the upper edge of the through hole Package for electronic components. 2. A through hole penetrating up and down of a package body.
In addition, a radiating member formed in a stepped shape has
Inserted from below the package body with a clearance fit
An electronic component package, wherein the heat radiating member is the package.
After being integrated with the cage body, Ni plating and Au plating
A gap formed between an inner surface of the through hole and an outer surface of the upper portion.
The reflux of the cleaning solution in the cleaning of the plating solution after the plating is
For ease, the inner surface of the through hole is
A concave groove extending from the edge to the lower edge side is formed to locally control the width of the gap.
A package for electronic components characterized by a localized expansion. 3. A through hole penetrating up and down of a package body.
In addition, a radiating member formed in a stepped shape has
Inserted from below the package body in a clearance fit state,
Release the metallized layer on the underside of the package body.
For electronic components with the upper surface of the lower part of the heat member brazed
A package, wherein the heat radiating member is the package body.
After being integrated with Ni, Ni plating and Au plating are applied.
A gap formed between an inner surface of the through hole and an outer surface of the upper portion.
The reflux of the cleaning solution in the cleaning of the plating solution after the plating is
For ease, the inner surface of the through hole is
A concave groove extending from the edge to the lower edge side is formed to locally control the width of the gap.
A package for electronic components characterized by a localized expansion. 4. An inner surface of the through-hole and an outer surface of the upper step are each substantially rectangular in plan view, and the concave groove is formed at least substantially at a center of each side of the square on the inner surface of the through-hole. The electronic component package according to any one of claims 1, 2 and 3, wherein: 5. An inner surface of the through hole and an outer surface of the upper portion are each substantially rectangular in plan view, and the concave groove is formed at least at each corner of the square of the inner surface of the through hole. The electronic component package according to claim 1, wherein: