JP3544283B2 - Package for electronic components - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a package for electronic components used for sealing electronic components such as integrated circuit chips. More specifically, the present invention relates to an electronic component package (hereinafter, also simply referred to as a package ) in which a heat radiating member (heat sink) is fixed to a ceramic laminated type package body (hereinafter, also simply referred to as a package body or simply a main body ) by brazing.
[0002]
[Prior art]
Among the laminated ceramic type packages provided with a heat dissipating member, those 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 are shown in FIG. 7 is shown. The package 100 includes a through hole 104 in which the inner peripheral side of the bonding pad forming surface 102 of the package main body 101 is substantially square, for example, in plan view (when viewed from above), and penetrates (opens) vertically (from upper surface to lower surface). ing. A heat dissipating member 201 made of copper tungsten (infiltration material) or the like having a through-hole 104 formed in a vertical cross section from the lower surface 105 side of the main body 101 and having a Ni (nickel) plating on the surface is formed on the upper portion 202. The main body 101 is configured such that it is inserted in a gap-fitted state and the upper surface (shoulder surface) 204 of the lower step portion 203 is brazed to the lower surface (back surface) 105 of the main body 101.
[0003]
In the package 100 thus configured, the upper surface 202a of the upper portion 202 of the heat radiation member 201 forms a die attach surface (a portion to which the integrated circuit chip is fixed), and the mounted integrated circuit chip (not shown) and the main body. The height of each bonding pad 101 (not shown) is set to be uniform. In such a package 100 shown in the same figure, the lower surface 203a of the heat radiation member 201 has a protruding shape with respect to the lower surface 105 of the main body 101. Therefore, the entire lower surface of the package 100 is formed in one plane (flat). It has not been. However, even in this type of package, there is a demand that the entire lower surface of the package be flat, and that the entire lower surface be in contact with a wiring board on which the package is mounted.
[0004]
[Problems to be solved by the invention]
In response to such a demand, if the structure of the conventional package 100 is to be formed so that the entire lower surface thereof becomes one plane, as shown by a two-dot chain line in FIG. It is necessary to have the same size as the lower surface 105 of the main body 101, and the heat radiation member itself becomes extremely large. However, this kind of heat dissipating member 201 made of copper tungsten or the like is extremely expensive. Therefore, if the flatness (corporality) of the entire lower surface of the package is to be ensured in this way, the manufacturing cost will be significantly increased. In addition, if the size of the heat dissipating member is increased, the size of the package (device) and the weight thereof may be increased.
[0005]
As a means for solving such a problem, the inventor of the present application arranges the heat radiating member 210 in the through-hole 114 so as to close the through-hole 114 of the main body 111 and brazes the same as in a package 110 shown in FIG. Can be proposed. That is, in the through hole 114 of the package body 111, a portion of the ceramic layer 130, which forms a portion near the upper surface of the body 111, of the inner peripheral surface protrudes inward along the inner periphery of the through hole 114. An inner peripheral protruding portion 136 is formed, and a concave portion having an L-shaped cross section is provided between the lower surface 137 of the inner peripheral protruding portion 136 and the lower surface 115 of the main body 111, and the lower surface 137 side of the inner peripheral protruding portion 136 is formed. It is a brazing surface for brazing the heat radiation member 210. The Ni-plated heat dissipating member 210 forms an outer peripheral protruding portion 235 protruding outward along the outer periphery at a portion of the outer peripheral surface near the lower surface. The upper surface 236 is a brazing surface. Thus, the brazing surface of the heat radiating member 210 is brazed to the brazing surface 137 of the through hole 114 so that the lower surface 233 of the heat radiating member 210 forms a plane with the lower surface 115 of the main body 111. That is.
[0006]
In this way, the flatness of the lower surface of the package 110 is ensured without increasing the size of the heat radiating member 210 as compared with that of FIG. However, the package main body 111 constituting such a package 110 is in an overhanging state in which the inner peripheral protruding portion 136 projects in a cantilever shape in the cross section in FIG. 8 as shown in FIG. The following problems may occur. That is, when firing a green ceramic laminate in which ceramic green sheets are laminated and thermocompressed, the lower surface of the green ceramic laminate is placed on a heat-resistant plate in order to protect the upper surface of the main body. For this reason, in the structure proposed above, in the firing step, the overhanging outer peripheral projection 136 hangs down due to its own weight and is deformed, and the flatness of the lower surface 137 forming the brazing surface of the heat radiation member 210 is reduced. Impair. Such a decrease in flatness also causes a reduction in sealing performance as a package when the heat radiating member 210 is brazed, and may reduce the reliability of the device.
[0007]
In the proposed technique, it is conceivable to prevent such drooping by making the protrusion amount of the outer peripheral protrusion portion 136 minute. However, as the protrusion amount decreases, the width of the brazing surface decreases, and conversely, The danger of impairing the sealing performance increases. Incidentally, in order to secure sufficient sealing performance in brazing such a portion, generally, the width of the brazing is required to be at least 1 mm.
[0008]
The present invention has been devised in view of such a point, and an object of the present invention is to provide a package for an electronic component with a heat radiating member, but to reduce such a decrease in sealing performance due to brazing of the heat radiating member. An object of the present invention is to provide an electronic component package in which a high degree of flatness of the entire lower surface is maintained without inviting the heat dissipation member and increasing the cost and the size of the entire device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 has a through hole vertically penetrating, and a ceramic radiating type electronic component to which a heat radiating member is fixed by brazing so as to close the through hole. In the package body, a portion of a plurality of ceramic layers continuous from one ceramic layer forming the lower surface of the electronic component package body in the inner peripheral surface of the through hole is formed along the inner periphery of the through hole. An electronic component package main body that forms an inner peripheral protruding portion protruding in the direction, and the upper surface side of the inner peripheral protruding portion serves as a brazing surface for brazing the heat radiating member ;
An electronic component package comprising: a heat dissipating member arranged in the through hole and fixed to the brazing surface by brazing;
The heat dissipating member includes an outer peripheral protruding portion formed by projecting outward along an outer periphery of the outer peripheral surface at a predetermined height above the lower surface of the heat dissipating member, and a lower surface side of the outer peripheral protruding portion. As a brazing surface, and is brazed to the brazing surface of the inner peripheral protruding portion in the through-hole, and after this brazing, the lower surface of the heat radiating member is flush with the lower surface of the electronic component package body. Thus, both lower surfaces are polished. According to a second aspect of the present invention, there is provided a ceramic laminate type electronic component package body having a through-hole vertically penetrating, and a heat-dissipating member fixed by brazing to close the through-hole. The hole has an inner peripheral projection formed by inwardly projecting a portion of one ceramic layer forming the lower surface of the electronic component package body along the inner periphery of the through hole. An electronic component package body in which an upper surface side of the inner peripheral projection is a brazing surface for brazing the heat radiating member ;
An electronic component package comprising: a heat dissipating member arranged in the through hole and fixed to the brazing surface by brazing;
The heat dissipating member includes an outer peripheral protruding portion formed by projecting outward along an outer periphery of the outer peripheral surface at a predetermined height above the lower surface of the heat dissipating member, and a lower surface side of the outer peripheral protruding portion. As a brazing surface, and is brazed to the brazing surface of the inner peripheral protruding portion in the through-hole, and after this brazing, the lower surface of the heat radiating member is flush with the lower surface of the electronic component package body. Thus, both lower surfaces are polished.
[0010]
Oite electronic component package body constituting the said means, the inner peripheral protruding portions for brazing of the heat radiating member is not a overhanging state when placed on a flat surface and the lower surface of the main body below. Therefore, when a raw (pre-firing) package body formed by laminating predetermined ceramic green sheets is placed on a flat mounting surface in a firing furnace with its lower surface facing down, and firing is performed in that state. In the firing process, the inner peripheral projection does not sag and does not deform. Therefore, a high degree of flatness is maintained on the brazing surface formed by the upper surface of the inner peripheral projection. Thus, the book body, the heat radiating member is, of its outer peripheral surface, the predetermined height above the lower surface of the heat radiation member provided with an outer protrusion formed by protruding outward along its periphery, said The lower surface side of the outer peripheral projection is brazed to the brazing surface of the inner peripheral projection in the through hole, and after this brazing, the lower surface of the heat radiating member is attached to the electronic component package body. In the package according to the present invention in which both lower surfaces are polished so as to be flush with the lower surface, a package having the lower surface flush with one surface can be obtained without lowering the sealing performance.
[0011]
In order to make the upper surface side of the inner peripheral protruding portion a brazing surface, for example, before firing, a high melting point metal paste such as W (tungsten) or Mo (molybdenum) is printed and applied with a predetermined width on the upper surface side. The metallized layer (metal layer) may be formed by simultaneous firing, and Ni plating or the like may be applied on the metallized layer. In the main body of the above means, the ceramic layer forming the inner peripheral protruding portion is a plurality (ceramic layer) continuous from one ceramic layer forming the lower surface of the main body, but this number is appropriately determined according to the package main body. Just design.
[0012]
That is, the ceramic layer forming the inner peripheral protrusions, depending on the package body, as described in claim 2, instead of a plurality of consecutive 1 ceramic layer forming a lower surface of the main body, the main body It may be formed by only one ceramic layer forming the lower surface. That is, an inner peripheral projection formed by projecting a portion of one ceramic layer, which forms the lower surface of the electronic component package body, of the inner peripheral surface of the through hole inward along the inner periphery of the through hole. And the upper surface side of the inner peripheral projection may be a brazing surface for brazing the heat radiating member. Further, in each of the above-described means, the brazing surface is formed to have a substantially constant width along the inner periphery of the through-hole . However, it is appropriate that the size is 1 mm or more. For this reason, the size of the heat radiating member exposed to the outer periphery of the package body becomes smaller, and the heat radiating effect becomes worse.
[0014]
As described above, in the package according to the first or second aspect of the present invention, there is no reduction in sealing performance due to brazing of the heat radiation member, and the cost increase and the overall size of the device due to an increase in the size of the heat radiation member are caused. Not even. Then, it is possible to obtain an electronic component package in which flatness is maintained over the entire lower surface. The flatness is determined by the thickness of the inner peripheral projection of the main body and the heat radiating member, that is, the height from the lower surface of the main body to the upper surface (brazing surface) of the inner peripheral protruding portion, and the lower surface of the heat radiating member to the outer periphery. The height to the lower surface of the protruding portion is made the same, and after both are brazed, the both lower surfaces are polished (ground) in accordance with the required flatness of the lower surface of the entire package to obtain a desired height. Flatness can be obtained.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described in detail with reference to FIGS. In FIG. 1, reference numeral 1 denotes a package body 1 of a ceramic laminate type for forming an electronic component package, which is configured as follows. That is, the package body 1 is formed in a substantially rectangular thin plate shape by laminating a plurality of predetermined green sheets, thermocompression bonding, and firing. A predetermined wiring layer (not shown) is formed on the upper surface 2 thereof, and a substantially square frame shape is formed in a plan view. And a raised portion 3 which is raised. Further, a through-hole 4 is formed in a portion near the center of the formation surface 2a and penetrates (opens) vertically (upper surface to lower surface) in a substantially square shape.
[0016]
However, in the present example, of the inner peripheral surface 4 a of the through hole 4, the portions of the ceramic layers 21 to 23 corresponding to three layers from the lower surface 5 of the main body 1 are arranged along the inner periphery of the through hole 4. The inner peripheral protruding portion 6 is formed so as to protrude inward from the portion formed by the ceramic layers 24 and 25 by a predetermined amount (for example, 1.2 mm). In this embodiment, the through-hole 4 is formed in a small square in a plan view, in which the portion of the main body 1 near the lower surface 5 is concentric with the portion near the upper surface 2. The upper surface 7 of the inner peripheral protruding portion 6 in the through hole 4 has a fixed width (substantially the entire protruding amount in this example) and a brazing surface (region indicated by double hatching) for brazing the heat radiating member 31 to be described later. 7a. However, a metallized layer made of W (tungsten), Mo (molybdenum) or the like is formed on substantially the entire upper surface 7 of the brazing surface 7a by simultaneous firing with the main body 1, and the surface is plated with Ni (nickel). ing.
[0017]
In addition, like the conventional ceramic laminated package or wiring board, such a main body 1 is formed by laminating ceramic green sheets formed by printing (applying) a predetermined metallized (conductor) paste, and thermocompression bonding. It is manufactured by cutting into substrates and firing them simultaneously. At this time, with respect to the ceramic green sheet at the portion where the brazing surface 7a is formed, the metallizing paste is also printed on the upper surface 7 of the portion forming the inner peripheral protruding portion 6.
[0018]
In the firing process of the main body 1, the main body 1 is fired on a flat surface with its lower surface 5 facing down. At this time, since the inner peripheral projection 6 does not become overhanging, The site does not sag and deform under its own weight. Therefore, a desired package body 1 in which the flatness of the upper surface 7 is not impaired can be obtained. After that, in such a main body 1, Ni plating and Au plating are applied to the brazing surface 7a and the metallized layer forming the bonding pad.
[0019]
FIGS. 3 and 4 show a heat radiation member 31 to be brazed to the main body 1. In this example, the heat radiation member 31 is made of copper tungsten (infiltration material), and is entirely plated with Ni. Have been. This is in the form of a flat plate having a certain thickness and a substantially square shape in plan view. However, a portion of the outer peripheral surface 32 that is closer to the upper surface 34 by a predetermined height H than the lower surface 33 is outwardly protruded along the outer periphery with a constant thickness and a constant protrusion amount (width). The outer peripheral projection 35 is provided. The height H is set to be substantially the same as the thickness T of the inner peripheral protruding portion 6 in the through hole 4 of the main body 1, and the lower surface 36 of the outer peripheral protruding portion 35 is formed flat. However, the height H is small, but the metallized layer, the plating and the brazing material on the brazing surface 7a of the main body 1 each have a small thickness. It is set higher than T.
[0020]
Then, as shown in FIG. 5, when such a heat radiating member 31 is fitted into the through hole 4 of the main body 1 from the upper surface 2 side with the outer peripheral projecting portion 35 side up, the following occurs. It seems. In other words, the heat dissipating member 31 has a portion near the upper surface 34 including the outer peripheral projecting portion 35 placed on the upper surface 7 of the inner peripheral projecting portion 6 in the through hole 4 of the main body 1. It is in the fitted state. Further, a portion of the lower surface 33 closer to the inner peripheral surface 6 a of the inner peripheral protruding portion 6 is in a gap fitted state, and is configured to be disposed in the through hole 4. In such a state, when the heat radiating member 31 is brazed to the through hole 4 of the main body 1, the upper surface 7 of the inner peripheral projecting portion 6 in the through hole 4 and the outer peripheral projecting portion 35 of the heat radiating member 31 By arranging a predetermined silver solder (preform) on the lower surface (flat surface) 36 and performing reflow, both are soldered and sealed.
[0021]
In the package 51 with the heat radiation member 31 thus configured, the lower surface 5 of the main body 1 and the lower surface 33 formed by the heat radiation member 31 are flush with each other, as shown in FIG. Secured. In such a package 51, since the inner peripheral protruding portion 6 of the main body 1 does not hang down, there is no reduction in sealing performance. In addition, the heat dissipating member 31 only needs to be arranged in the through hole 4 as shown in the figure, so that the size of the heat dissipating member 31 can be reduced . Then, after brazing, the lower surfaces of the main body 1 and the heat dissipating member 31 may be polished so that the lower surface of the package 51 has a predetermined coplanarity .
[0022]
In addition, after the heat radiation member 31 is brazed, such a package 51 is provided with input / output of bonding pads, pins, etc. on the die attach surface (upper surface 34) and lower surface 33 of the heat radiation member 31 and the lower surface 33 to prevent corrosion. Terminals (not shown) and the like are plated with Ni and Au (gold) to complete the package whose entire lower surface is flat. Incidentally, when a metal layer (film) is formed on the entire lower surface of the package 51 by sputtering or the like, and conduction with a castellation (not shown) formed on the outer peripheral surface (side surface) of the main body 1 is secured, Ni plating and Au plating may be performed after the formation of the metal layer. In the package completed in this way, an integrated circuit chip or the like (not shown) is soldered to the upper surface (die attach surface) 34 of the heat radiating member 31 with a brazing material (Au-Sn or the like) in a later process, and thereafter, wire-bonded. A lid which is not covered is placed on the raised portion 3 and sealed by soldering.
[0023]
In the above embodiment, the inner peripheral protruding portion 6 of the main body 1 is formed of three ceramic layers 21 to 23 above the ceramic layer 21 forming the lower surface 5 of the main body 1. What is necessary is just to design according to the thickness of a main body, the number of ceramic layers, etc., and it can be set to two layers, or four or more layers. Further, as shown in FIG. 6, of the inner peripheral surface 4 a of the through hole 4, only the portion of the one ceramic layer 21 forming the lower surface 5 of the main body 1 is turned inward along the inner periphery of the through hole 4. The inner peripheral projection 6 is made to protrude, and the upper surface 7 of the inner peripheral projection 6 does not overhang even if it is used as a brazing surface for brazing the heat radiating member. Therefore, it is clear that the same operation and effect as in the previous example are obtained, including the case where the heat radiating member 31 is brazed as shown by the two-dot chain line in FIG. And the description thereof is omitted.
[0024]
The main body and the package including the same according to the present invention may be embodied as long as the heat radiating member is brazed in a form of a ceramic laminate type having a vertically penetrating through hole and closing the through hole. Regardless of the shape, structure and material of the above, including the shape, the present invention can be applied to various types such as PGA (pin grid array) and LGA (land grid array). Also, the heat dissipating member is not limited to the above-mentioned shape, and the material may be a known material such as copper molybdenum (infiltration material) or a clad material such as copper-molybdenum-copper. Can be Further, the thickness of the outer peripheral protruding portion is set so that the lower surface of the package becomes flat when brazed to the upper surface (brazing surface) of the inner peripheral protruding portion in the through hole of the main body. An appropriate thickness may be designed according to the thickness.
[0025]
【The invention's effect】
As is clear from the above description , according to the package according to the present invention, the brazing surface of the heat radiation member in the package body protrudes along the inner periphery of the through hole without overhanging. Since it is the upper surface of the peripheral protruding part, the part does not sag and deform during the firing process of the main body .
[0026]
Further , according to the package of the present invention, there is no reduction in sealing performance due to brazing of the heat radiation member. In addition, it is possible to provide an electronic component package in which a high degree of flatness is maintained on the entire lower surface without increasing the cost due to an increase in the size of the heat radiation member or increasing the size of the entire device.
[Brief description of the drawings]
FIG. 1 is a central longitudinal sectional view of an embodiment embodying a package body according to the present invention.
FIG. 2 is a plan view of FIG. 1;
FIG. 3 is a view of a heat radiation member brazed to a package body as viewed from an outer peripheral surface side.
FIG. 4 is a plan view of the heat radiation member of FIG. 3;
5 is a central longitudinal sectional view of a package obtained by brazing the heat radiation member of FIG. 3 to the package body of FIG. 1;
FIG. 6 is a central longitudinal sectional view of another embodiment embodying a package body according to the present invention.
FIG. 7 is a longitudinal sectional view showing an example of a conventional heat slug type package.
FIG. 8 is a central longitudinal sectional view of a package structure in which a problem is partially solved by improving a conventional heat slug type package.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main body 2 Main body upper surface 4 Through hole 4a Inner peripheral surface of through hole 5 Lower surface of main body 6 Inner peripheral protruding portion 7 Upper surface of inner peripheral protruding portion 7a Brazing surface 21 Ceramic layer 31 forming lower surface of main body Heat dissipation member 32 Outer peripheral surface 33 of heat dissipating member Lower surface 33 of heat dissipating member Upper surface 35 of heat dissipating member 36 Outer peripheral protruding portion 36 Lower surface of protruding portion 51 Electronic component package T Thickness of inner peripheral protruding portion H From lower surface of heat dissipating member to lower surface of outer peripheral protruding portion height

Claims (2)

The package body for an electronic component of a ceramic laminate type, which has a through hole penetrating vertically and a heat dissipation member is fixed by brazing to close the through hole, wherein the through hole has an inner peripheral surface thereof. Forming a plurality of continuous ceramic layers from one ceramic layer forming the lower surface of the electronic component package body inwardly along the inner circumference of the through hole; An electronic component package body in which the upper surface side of the protrusion serves as a brazing surface for brazing the heat radiating member ,
An electronic component package comprising: a heat dissipating member arranged in the through hole and fixed to the brazing surface by brazing;
The heat dissipating member includes an outer peripheral protruding portion formed by projecting outward along an outer periphery of the outer peripheral surface at a predetermined height above the lower surface of the heat dissipating member, and a lower surface side of the outer peripheral protruding portion. As a brazing surface, and is brazed to the brazing surface of the inner peripheral protruding portion in the through-hole, and after this brazing, the lower surface of the heat radiating member is flush with the lower surface of the electronic component package body. A package for an electronic component , the lower surfaces of which are polished . The package body for an electronic component of a ceramic laminate type, which has a through hole penetrating vertically and a heat dissipation member is fixed by brazing to close the through hole, wherein the through hole has an inner peripheral surface thereof. An inner periphery protruding portion is formed by projecting the portion of one ceramic layer forming the lower surface of the electronic component package body inward along the inner periphery of the through hole, and the upper surface side of the inner periphery protruding portion is An electronic component package body serving as a brazing surface for brazing the heat radiating member ;
An electronic component package comprising: a heat dissipating member arranged in the through hole and fixed to the brazing surface by brazing;
The heat dissipating member includes an outer peripheral protruding portion formed by projecting outward along an outer periphery of the outer peripheral surface at a predetermined height above the lower surface of the heat dissipating member, and a lower surface side of the outer peripheral protruding portion. As a brazing surface, and is brazed to the brazing surface of the inner peripheral protruding portion in the through-hole, and after this brazing, the lower surface of the heat radiating member is flush with the lower surface of the electronic component package body. A package for an electronic component , the lower surfaces of which are polished .

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