JPH0945827A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the temperature difference between the temperatures of electronic components and to make uniform the output signal levels of devices by a method wherein at least one of heat conductors, which are respectively mounted to a plurality of the electronic components and transfer heat, which is generated in the components, to cooling components, has a heat conductivity different from those of the other heat conductors. SOLUTION: A plurality of electronic components 13, 14 and 15 are mounted on the upper surface of a wiring board 11, which consists of a ceramic board made of an alumina or a mullite, through solder balls as connection means. Here, the components 13 are CPUs and the components 14 and 15 are memory elements. Here, heat conductors 31, 32 and 33 are respectively connected with the upper parts of the components 13, 14 and 15 and the heat conductors 31, 32 and 33 are respectively connected thermally with the recess parts in the centers of cooling components 6. Moreover here, materials having heat conductivities different from each other are respectively used for conductors 31, 32 and 33. In concrete terms, Cu, Si and Mo are respectively used for the conductor 31, the conductor 32 and the conductor 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a plurality of electronic components mounted and connected on a wiring board and having cooling components on the electronic components.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device called a multi-chip module has generally mounted a plurality of electronic components of the same type on a wiring substrate such as a ceramic substrate. For example, as described in JP-A-6-77361, cooling is performed by a structure in which an LSI chip and a heat sink are thermally connected by a heat conductive material. Here, since there is no large difference in the heat generation amount of each chip, even if cooling is performed using the heat conductive material having the same structure, there is no large difference in the operating temperature of each chip.

However, in recent years, with the increase in the degree of integration, there is an increasing need to increase the speed of a semiconductor device by bringing a high-speed CPU, which generates a large amount of heat, and a memory element, which generates a relatively small amount of heat, close to each other.

[0004]

As is well known, in order to equalize the signal levels output from a large number of devices embodied in a module, the operating temperature of each electronic component must be within a certain range. Need to fit within. But,
In the conventional structure, the heat generated by the CPU causes a temperature difference exceeding the allowable range between the CPU and the memory element. Further, when the thermal conductors having the same thermal conductivity are used as the thermal conductors connected to the memory element near the CPU and the memory element located far from the CPU, the operating temperature of the memory near the CPU is
Higher than the operating temperature of the memory away from. That is, no consideration was given to keeping the operating temperature of each electronic component within a certain range.

An object of the present invention is to make the output signal level of each device uniform by reducing the temperature difference between the electronic components and to further stabilize the operation of the semiconductor device.

[0006]

The above object is to provide a wiring board, a plurality of electronic parts mounted on the board, and a heat conductor mounted on the electronic parts and for transferring heat generated in the electronic parts to a cooling part. In the semiconductor device made of, at least one of the heat conductors has a thermal conductivity different from that of the other heat conductors.

[0007]

According to the above means, a heat conductor having a relatively high heat conductivity is used as the heat conductor in contact with the CPU, and a heat conductor having a relatively low heat conductivity is used as the heat conductor in contact with the memory element. The body can be used. Further, a heat conductor having a relatively high heat conductivity is used as a heat conductor connected to the memory near the CPU, and a heat conductor having a relatively high heat conductivity is used as a heat conductor connected to the memory located away from the CPU. Low heat conductors can be used. As a result, the temperature difference between the CPU and the memory element is reduced as compared with the conventional case, and the temperature difference between the memory element near the CPU and the memory element distant from the CPU is reduced. As a result, the output signal levels of the CPU and each memory element can be made uniform.

[0008]

1 is a sectional view of a semiconductor device 101a according to a first embodiment of the present invention.

The wiring board 11 is made of, for example, a ceramics board made of alumina or mullite. This wiring board 11
On the upper surface, Pb / Sn (95/5 wt) is used as the connecting means 12.
%) Solder balls made of a plurality of electronic components 13,
14 and 15 are mounted. The connecting means 12 takes the form of a protruding electrode using a solder ball when the electronic component form is BGA or a bare chip, and the electronic component form is QFP or TCP.
In the case of, it takes the form of metal leads attached to the package.
Here, the electronic component 13 is a CPU, and the electronic components 14 and 15 are memory elements.

Further, a cooling component 16 is arranged above the electronic components 13, 14 and 15 so as to cover it. Here, the cooling component 16 is made of ceramics such as AlN, which is a material having high thermal conductivity and easy to process. Further, metals such as Al and Cu are desirable for improving productivity and reducing costs.
Furthermore, the periphery of the cooling component 16 is processed into a convex shape,
It is connected to the peripheral portion of the wiring board 11 by solder or the like (not shown). Here, heat conductors 31, 32 and 33 are connected to the upper parts of the electronic components 13, 14 and 15,
The heat conductors 31, 32 and 33 are thermally connected to the central recess of the cooling component 16. Here, the electronic component 13 is CP
Since it is U, its heat generation amount reaches 40 to 50 W, while the electronic components 14 and 15 are memory elements, so its heat generation amount is several W level.

In this embodiment, the heat conductors 31, 32 and 3 are
Materials having different thermal conductivity were used for No. 3. Specifically, the heat conductor 31 is Cu, the heat conductor 32 is Si, and the heat conductor 3 is
3 was Mo. The temperature distribution of each electronic component according to this embodiment is shown in FIG.

The horizontal axis represents the distance from the center of the wiring board, and the vertical axis represents the operating temperature of each electronic component. The figure shown below the graph is the semiconductor device 101a, and shows the arrangement and connection state of the wiring board 11 and the electronic components 13, 14 and 15.
Each of the electronic components 14 and 15 is a memory element, and its heat generation amount is 5 W. Further, the electronic component 13 is a CPU, and its heat generation amount is 40W.

The dotted line shows the distribution of operating temperature in the conventional structure. In the conventional structure, the heat conductors 31, 32 and 33 are
The heat conductivity of each heat conductor was made the same by using Cu having the same thickness. Since the thermal resistances between the electronic components 13, 14 and 15 and the external atmosphere are substantially equal to each other, the temperature rise of the electronic component 13 having a large heat generation amount is the largest. Then, the electronic component 1 that is greatly affected by the amount of heat transmitted to the periphery of the electronic component 13
The temperature rise of 4 is the next largest, and the temperature rise of the electronic component 15 is the smallest. Difference in operating temperature of electronic parts 13, 14, 15 Δ
Ta reached 30 (° C).

The solid line shows the distribution of the operating temperature of this structure. For the heat conductor 31 connected to the electronic component 13, the same Cu as the conventional one is used.
Was used. As the material of the heat conductor 32 that contacts the electronic component 14 that is greatly affected by the amount of heat transferred from the electronic component 13 to the surroundings, Si having a smaller thermal conductivity than Cu was used. As a material of the heat conductor 33 which is in contact with the electronic component 15 in which the thermal influence of the electronic component 13 is relatively small, Mo having a smaller thermal conductivity than Si was used. These heat conductors 31, 32, 33
Had the same thickness. Since the thermal resistance between the electronic components 14 and the external atmosphere is larger than that of the conventional example, the temperature difference between the electronic components 13 and 14 is reduced as compared with the conventional example. Further, the thermal resistance between the electronic component 15 and the external atmosphere is
Since the thermal resistance between the electronic component 15 and the external atmosphere is larger than that of the conventional structure, the temperature rise of the electronic component 15 is further increased, and the temperature difference between the electronic components 14 and 15 is also reduced as compared with the conventional structure.

As a result, the operating temperature difference ΔTb between the electronic components 13, 14 and 15 is 5 (° C.), which can be reduced to about one sixth of the conventional one. For other reasons, Mo that is smaller than the heat conductivity of the heat conductor Cu is used for the heat conductor 32, and Al ₂ O that has a smaller heat conductivity than the Mo used for the heat conductor 32 is used for the heat conductor 33. The same effect can be obtained by using ₃ .

FIG. 3 is a sectional view of a semiconductor device 101b according to a second embodiment of the present invention.

The semiconductor device 101b is the semiconductor device 101.
This is an example in which the heat conductors 31, 32, and 33 in a are composed of a plurality of parts. That is, the heat conductors 36, 37 and 38 are formed by laminating the heat conductors 31, 32 and 33 and the heat conductor 34, respectively.

In this embodiment, a plurality of heat conductors are laminated so that the heat conductors 36, 37 and 38 have different thermal conductivities. Specifically, the heat conductor 34 has Pb / Sn (37 /
63 wt%) and heat conductors 31, 32 and 33
Used Cu, Si and Mo respectively as in the first embodiment. Similar to the first embodiment, electronic components 13, 14, 1
Since the thermal resistance to the external atmosphere increases in the order of 5, the temperature difference between the electronic components can be reduced as compared with the conventional example. Also, any three kinds of Cu, AlN, SiC, Al, W, Si or Mo are selected in order of increasing thermal conductivity from the electronic component 13,
The same effect can be obtained by arranging 14 and 15.

FIG. 4 is a sectional view of a semiconductor device 101c which is a third embodiment of the present invention.

The semiconductor device 101c is the semiconductor device 101.
a of the heat conductors 31, 32 and 33 to the heat conductors 45, 4
The structure is replaced with 6 and 47. These heat conductors 45, 46 and 47 are composed of two parts, a heat conductor 40 and a heat conductor 41. Then, the thickness of the heat conductor 40 in contact with the electronic component 13 was made thickest, and the thickness of the heat conductor 40 in contact with the electronic component 15 was made thinnest. Here the heat conductor 4
Cu is used as the material of 0, and the material of the heat conductor 41 is Pb / Sn (37/6) having a smaller thermal conductivity than Cu.
3 wt%) was used. According to the above configuration, as in the first embodiment, the thermal resistance between the electronic components 13, 14 and 15 and the external atmosphere increases in this order, so that the temperature difference between the electronic components can be reduced compared to the conventional example. It can be reduced.

FIG. 5 is a sectional view of a semiconductor device 101d according to a fourth embodiment of the present invention.

The semiconductor device 101c is the semiconductor device 101.
a of the heat conductors 31, 32 and 33 to the heat conductors 48, 4
The structure is replaced with 9 and 50. The contact area of the heat conductor 48 in contact with the electronic component 13 was maximized, and the contact area of the heat conductor 50 in contact with the electronic component 15 was minimized. Here, Cu was used as the material of the heat conductors 48, 49, 50. According to the above configuration, as in the first embodiment, the thermal resistance between the electronic components 13, 14 and 15 and the external atmosphere increases in this order, so that the temperature difference between the electronic components is smaller than that in the conventional example. It can be reduced.

[0023]

According to the present invention, it is possible to reduce the difference in operating temperature between electronic components of the same type in a semiconductor device in which a plurality of electronic components are mounted at high density. The level becomes uniform, and the operation of the semiconductor device can be further stabilized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device in which a plurality of electronic components according to an embodiment of the present invention are mounted on a wiring board and the electronic components and cooling components are connected by a heat conductor.

FIG. 2 is a temperature distribution diagram of a conventional semiconductor device and a temperature characteristic according to the present structure.

FIG. 3 is a cross-sectional view of a semiconductor device in which a plurality of electronic components according to an embodiment of the present invention are mounted on a wiring board and the electronic components and the cooling components are connected by a heat conductor.

FIG. 4 is a cross-sectional view of a semiconductor device in which a plurality of electronic components according to an embodiment of the present invention are mounted on a wiring board and the electronic components and the cooling components are connected by a heat conductor.

FIG. 5 is a cross-sectional view of a semiconductor device in which a plurality of electronic components according to an embodiment of the present invention are mounted on a wiring board and the electronic components and the cooling components are connected by a heat conductor.

[Explanation of symbols]

11 ... Wiring board, 12 ... Projection electrode, 13 ... CPU component,
14 ... Memory component, 15 ... Memory component, 16 ... Cooling component, 31 ... Thermal conductor, 32 ... Thermal conductor, 33 ... Thermal conductor, 101a ... Semiconductor device.

Claims (8)

[Claims] 1. A semiconductor device comprising a wiring board, a plurality of electronic parts mounted on the board, and a heat conductor mounted on the electronic parts and transmitting heat generated in the electronic parts to a cooling part, A semiconductor device, wherein at least one of the conductors has a different thermal conductivity from other heat conductors. 2. The semiconductor device according to claim 1, wherein at least one of the thermal conductors is made of a material having a thermal conductivity different from that of the other thermal conductors. 3. The semiconductor device according to claim 1, wherein the thermal conductor is formed by laminating a plurality of materials having different thermal conductivities. 4. The semiconductor device according to claim 3, wherein the thickness of at least one of the plurality of materials forming the heat conductor is different from the thickness of the material forming the other heat conductor. 5. The semiconductor device according to claim 1, wherein at least one of the heat conductors has a connection area different from other heat conductors with the electronic component. 6. The method of claim 1, 2, 3, 4, or 5,
A semiconductor device in which the electronic component is a bare chip. 7. The method according to claim 1, wherein
The electronic component is a semiconductor device including a package for surface implementation such as QFP, BGA, TCP. 8. The method of claim 1, 2, 3, 4, or 5,
A semiconductor device in which at least one of the materials forming the heat conductor is solder.