JPH06112377A - Ceramic package - Google Patents

Abstract

PURPOSE:To avoid the occurrence of narrow gap easy for plating cleaning liquid, etc., to remain by arranging the gap between a hole, which passes through from obverse to reverse, piercing each layer of a package body, and a projection so that it may be not below the value equivalent to the difference between the area of the opening of one layer of a heat sink and the area of the other layer. CONSTITUTION:The area (the length of one side is Da) of the opening of a layer A, which is in contact with a heat sink 13, out of the body 10 is set to be smaller than that (the length of one side is Db or Dc) of the opening of other than the layer A. That is, they are in the relation of Da=Db-alpha=Dc-beta, and alpha is equivalent to the difference between Da and Db, and beta is equivalent to the difference between Da and Dc. Accordingly, in case that the heat sink 13 is biased to left side, the gap Lb between the projection 13a of the heat sink 13 and the second hole 11b is limited by alpha/2, so the occurrence of narrow gap easy for plating cleaning liquid to remain can be avoided, therefore it ceases to have adverse effect such as corrosion, etc., on the peripheral plated section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic package which is a kind of airtight container for semiconductors, and more particularly to a ceramic package having improved heat dissipation.

[0002]

2. Description of the Related Art FIG. 4A is a structural view (however, lead pins are omitted) of a conventional ceramic package with improved heat dissipation, in which a package body 1 made of a ceramic material is used.
The convex portion 2a of the heat sink 2 made of a metallic material is inserted into the hole 1a formed in the above, and the IC chip 3 is attached to the convex portion 2a (that is, a part of the heat sink 2). In addition, 4 is a wiring pattern and 5 is a bonding wire.

[0003]

However, in such a conventional ceramic package, when the convex portion 2a of the heat sink 2 is inserted into the hole 1a of the package body 1, the horizontal position of the convex portion 2a (left and right in the drawing). (Direction position) may deviate, and for example, when it deviates to the left side of the drawing, as shown in FIG. 4B, a very narrow gap La is created between the hole 1a and the convex portion 2a, and this gap La For example, there is a problem in quality control that, for example, a plating cleaning liquid remaining in La gradually exudes and adversely affects the surrounding plated portion such as corrosion. [Purpose] Therefore, an object of the present invention is to provide a high quality ceramic package with a heat sink by avoiding the occurrence of a narrow gap in which a plating cleaning liquid or the like is likely to remain.

[0004]

In order to achieve the above object, the present invention provides a package body in which green sheets are laminated and baked, and a hole penetrating each layer of the package body to communicate the front and back sides thereof. A ceramic package comprising a heat sink that abuts a front surface layer or a back surface layer of the package body and inserts a convex portion inside the hole to form a stage for an IC chip. The opening area of some continuous layers including the layer is made smaller than the opening area of another layer to form the hole, or one layer or the layer with which the heat sink abuts is formed. It is characterized in that a cross-sectional area of the convex portion facing the several continuous layers included therein is made larger than a cross-sectional area facing the other layers.

[0005]

According to the present invention, the gap between the hole and the convex portion has a value corresponding to the difference between the opening area of one layer of the heat sink and the opening area of the other layer, or the convex area facing these layers. It is restricted so that it does not become less than or equal to the value corresponding to the difference in cross-sectional area of the parts. Therefore, by optimizing each value, it is possible to avoid the occurrence of a narrow gap in which the plating cleaning liquid or the like is likely to remain.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of a ceramic package according to the present invention. In FIG. 1A, 10
Is a package body (hereinafter referred to as a body) made of a ceramic material, and is made by stacking a plurality of green sheets and baking at a high temperature. The main body 10 is formed with a hole 11 penetrating the front and back thereof, and the hole 11 is formed by cutting out the green sheet of each layer into a required shape. The hole 11 includes a first hole 11a for exposing the wiring pattern 12 and a second hole 11b for a cavity, and the second hole 11b has a heat sink 13 made of a metallic material.
The convex portion 13a is inserted. The upper surface of the convex portion 13 is an IC
It becomes the mounting stage of the chip 14. Reference numeral 15 is a bonding wire.

Here, among the layers of the main body 10 (the layers of the green sheet before firing), the layer in contact with the heat sink 13, that is, one layer A forming the opening of the second hole 11b or the one layer concerned. The opening area of a plurality of continuous layers including the layer A (hereinafter, represented by one layer A) (for convenience, 1
The side length Da is set to be smaller than the opening area other than the one layer A (similarly represented by one side length Db and Dc). That is, Da = Db-α
= Dc-β. However, α is a value corresponding to the difference between Da and Db, and β is a value corresponding to the difference between Da and Dc.

Therefore, the heat sink 13 is, for example, as shown in FIG.
As shown in (b), when the sheet is deviated to the left side in the drawing, the gap Lb between the convex portion 13a of the sheet sink 13 and the second hole 11b is limited by the difference value α / 2 (α / 2. Therefore, it is possible to provide a high quality ceramic package with a heat sink that can avoid the occurrence of a narrow gap in which a plating cleaning liquid or the like is likely to remain and which does not adversely affect the surrounding plated portion such as corrosion.

In the above embodiment, the second hole 11b is used.
Although only the opening area of the second hole 1 is made smaller, the present invention is not limited to this. For example, as shown in FIG.
The opening area may be sequentially reduced from the opening side of 1b '. That is, the wall surface of the second hole 11b may be provided with a stepwise inclination. Further, as shown in the plan view of the main part in FIG. 2B, one layer A may be parallel to each side of the convex portion 13a and opened (see the broken line X), or each of the convex portions 13a may be opened. You may incline and open for every corner (refer to the dashed-dotted line Y).

Alternatively, as shown in FIG. 3, the cross-sectional area of the convex portion of the heat sink may be changed. That is,
In FIG. 3, among the layers of the main body 20 (the layers of the green sheet before firing), the layer to which the heat sink 21 is in contact, in other words, one layer B forming the opening of the hole 22 or a continuous layer including the one layer B. The cross-sectional area (represented by the length Da ′ of one side for convenience) of the convex portion 21a facing the plurality of layers (hereinafter, represented by one layer B) faces the layers other than the one layer B. The cross-sectional area of the convex portion 21a (similarly to the length D of one side)
The value may be set to be larger by α than the value represented by b ′).

Even in this case, when the heat sink 21 is displaced to the left side in the drawing, for example, the gap between the convex portion 21a of the sheet sink 21 and the hole 22b is limited by the difference value α / 2 (α Therefore, it is possible to obtain the same effect as the above-mentioned embodiment.

[0012]

EFFECTS OF THE INVENTION According to the present invention, since it is configured as described above, it is possible to avoid the generation of a narrow gap in which the plating cleaning liquid and the like tend to remain, and to provide a high quality ceramic package with a heat sink.

[Brief description of drawings]

FIG. 1 is a structural view and a detailed view of essential parts of an embodiment.

FIG. 2 is a detailed view and a plan view of relevant parts showing a modified example of the embodiment.

FIG. 3 is a structural diagram of another embodiment.

4A and 4B are a structural view and a detailed view of a main part of a conventional example.

[Explanation of symbols]

 A, B: One layer 10, 20: Package body 11, 22: Hole 13, 21: Heat sink 13a, 21a: Convex part 14: IC chip

Claims (2)

[Claims] 1. A package body in which green sheets are laminated and baked, a hole penetrating each layer of the package body to communicate the front and back sides, and a convex portion which is in contact with a front surface layer or a back surface layer of the package body. In a ceramic package comprising a heat sink inserted into the hole to form a stage for an IC chip, the open area of one layer with which the heat sink abuts or several continuous layers including the layer is A ceramic package in which the hole is formed with a size smaller than the opening area of the layer. 2. A package main body in which green sheets are laminated and baked, a hole penetrating each layer of the package main body to communicate the front and back sides, and a convex portion abutting on a front surface layer or a back surface layer of the package main body. A ceramic package comprising: a heat sink inserted into the hole to form a stage for an IC chip, wherein the convex portion faces one layer with which the heat sink abuts or several continuous layers including the layer. The cross-sectional area of
A ceramic package characterized by having a larger cross-sectional area facing the other layers.