JPH08250650A - Semiconductor device - Google Patents

Abstract

PURPOSE: To provide a semiconductor device which is excellent in packaging density and can contribute to the miniaturization and the high speed operation of a system electronics product. CONSTITUTION: Semiconductor elements 3 are bonded and mounted on the bottom surfaces of cavities 2 formed on the central upper and lower surfaces of a ceramic multilayered board 1. Semiconductor elements 3 are bonded and mounted also on the inner surface of an upper lid 4 of a package and the inner surface of a lower lid 5. Thereby four elements can be mounted in a package, so that the packaging density is improved twice as compared with the conventional double-sided board mounting type device.

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 high mounting density of semiconductor elements.

[0002]

2. Description of the Related Art In a semiconductor device made by encapsulating a semiconductor element in a package, it is indispensable to increase the packaging density of the semiconductor element without expanding the area of the package in order to reduce the size and speed of system electronic products. It has become to.

FIG. 4 shows an example of a semiconductor device developed to meet the demand. In this device, a cavity 2 is provided on both upper and lower sides of the center of a ceramic laminated substrate 1 which is made by stacking a plurality of ceramic plates having circuit conductors.
A semiconductor element 3 is adhesively mounted on the bottom surface of each cavity 2 and the upper and lower surfaces of the substrate 1 are sealed by an upper lid 4 and a lower lid 5, which are disclosed in, for example, Japanese Patent Laid-Open No. 60-74659. There is.

[0004]

Since the semiconductor device is provided on both sides of the ceramic laminated substrate in the device of FIG. 4, the mounting density is doubled as compared with the conventional semiconductor device in which only one surface of the substrate is used as the mounting surface. ing. However, the structure in which two semiconductor elements are provided in one device cannot satisfy the demand for higher density.

Therefore, the first object of the present invention is to further increase the packaging density of semiconductor elements. Further, since this high-density mounting involves problems such as an increase in heat generation and an increase in malfunction due to electromagnetic noise, it is the second and third problems to deal with these problems.

[0006]

In order to solve the above problems, in the present invention, in addition to providing a cavity on the upper and lower surfaces of the center of a ceramic laminated substrate and bonding and mounting a semiconductor element on the bottom surface of each cavity, A structure in which a semiconductor element is adhesively mounted on the inner surface of at least one of the upper and lower lids is adopted.

Further, in some cases, a radiation fin is added to the upper surface of the upper lid, and a heat transfer plate between the printed wiring board and the lower lid is added to the lower lid. Furthermore, more preferably, an electromagnetic shield layer is added between the cavities on both sides of the ceramic laminated substrate and between the semiconductor elements in the same cavity.

[0008]

In the present invention, since the semiconductor elements are also mounted on the inner surface of the lid, the number of elements mounted in one package is three or four, and the mounting density is 1.
5 times or 2 times higher.

Further, in the case where the heat radiation fin and the heat radiation plate are added, the heat can smoothly escape through the upper lid and the lower lid, the heat radiation characteristic is improved, and the heat deterioration of the device and the performance deterioration due to the heat are suppressed. It

Further, between the cavities on both sides of the substrate, and
In the case where the electromagnetic shield layer is added between the semiconductor elements on the bottom surface of the cavity and the inner surface of the lid, mutual intrusion of electromagnetic noise between the elements is prevented, and malfunction of the elements due to electromagnetic noise is prevented.

[0011]

FIG. 1 shows a first embodiment of the semiconductor device of the present invention. In the figure, reference numeral 1 is a laminated ceramic substrate having a circuit conductor 7. This substrate 1 is made by laminating a required number of ceramic plates, has a cavity 2 in the center upper and lower surfaces, and a semiconductor element 3 is adhesively mounted on the bottom surface of each cavity 2.

Reference numeral 4 denotes an upper lid which is attached to the upper portion of the substrate 1, and 5 is a lower lid which is attached to the lower portion of the substrate 1. These lids are adhered and fixed to the substrate 1 with a low-melting glass or the like to form the upper and lower cavities 2.
Is sealed. The semiconductor element 3 is also adhesively mounted on the inner surfaces of the upper lid 4 and the lower lid 5.

Reference numeral 8 is a bonding wire for connecting each semiconductor element 3 to the corresponding circuit conductor 7. After the semiconductor element 3 is adhesively mounted on the inner surfaces of the upper lid 4 and the lower lid 5 and the elements are connected to the circuit conductor 7 provided on the inner surface of the lid by the bonding wires 8, the mounting and connection of the elements are completed. It is attached to the substrate 1.

The circuit conductor 7 is electrically connected to the corresponding lead pin 6, and connects the power supply, signal, and ground lead pins 6 to the power supply, signal, and ground circuits on the printed circuit board 11. The semiconductor device is mounted on the printed circuit board. In addition, the hole of the lower lid through the lead pin 6,
The gap between the lead pin is closed by glass sealing.

FIG. 2 shows a second embodiment. In this semiconductor device, a radiation fin 9 is attached on the upper lid 4 of the apparatus of FIG. 1, and a heat transfer plate 10 which is sandwiched between the lower lid and the printed circuit board 11 is added to the lower surface of the lower lid 5. is there. This device
The heat that has flowed to the upper lid 4 is released to the atmosphere via the radiation fins 9, and the heat that has flowed to the lower lid 5 is absorbed by the printed circuit board 11 that has a large surface area and large heat capacity via the heat transfer plate 10. The device temperature is kept low.

FIG. 3A shows a third embodiment in which an electromagnetic shield layer is added to the device of FIG. An electromagnetic shield layer 12 composed of a printed conductor, a conductor formed by vapor deposition or plating, or a foil conductor is provided between the two layers by partitioning the space between the upper and lower cavities 2 of the substrate 1 into two layers. Electromagnetic shield layer 1 between certain semiconductor elements
3 are provided. The electromagnetic shield layer 13 between the elements is shown in FIG.
The mesh conductor 13a as shown in (b) is used, and the periphery of the mesh conductor is sandwiched between the frame-shaped ceramic layers that form the cavity 2. If the electromagnetic shield layer 13 is provided with a frame coating layer on the surface, no problem occurs even if the bonding wire 8 comes into contact with the surface, and the space margin is small, so that the device can be further downsized.

The electromagnetic shield layers 12 and 13 are directly or indirectly connected to the ground lead pin.

In the third embodiment, since the electromagnetic shield layers 12 and 13 prevent mutual intrusion of electromagnetic noise between the respective semiconductor elements, malfunction of the semiconductor elements is unlikely to occur and reliability is further enhanced.

[0019]

As described above, according to the present invention,
Since the semiconductor element is also mounted on the inner surface of the package lid,
The number of mounted elements can be increased to 1.5 times or twice that of the conventional double-sided mounting type device without increasing the area of the package.

Further, since it is possible to improve the heat dissipation characteristic and reduce the malfunction of the element due to electromagnetic noise, it is possible to realize a small-sized high-density mounting semiconductor device which is highly reliable and has excellent durability. Further miniaturization and higher speed can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3A is a sectional view of a third embodiment. FIG. 3B is a perspective view of a mesh conductor used in the third embodiment.

FIG. 4 is a sectional view showing an example of a conventional semiconductor device.

[Explanation of symbols]

 1 Ceramic Laminated Substrate 2 Cavity 3 Semiconductor Element 4 Upper Lid 5 Lower Lid 6 Lead Pin 7 Circuit Conductor 8 Bonding Wire 9 Radiating Fin 10 Heat Transfer Plate 11 Printed Circuit Board 12, 13 Electromagnetic Shielding Layer 13a Mesh Conductor

Claims (3)

[Claims] 1. A ceramic laminated substrate, which constitutes a package in combination with an upper lid and a lower lid, has cavities on the upper and lower sides of the center thereof, and a semiconductor element is bonded and mounted on the bottom surface of each cavity and at least the inner surface of either the upper or lower lid. A semiconductor device characterized by the above. 2. The semiconductor device according to claim 1, wherein a heat radiation fin is added to an upper surface of the upper lid, and a heat transfer plate between the printed wiring board and the lower lid is added. 3. The semiconductor device according to claim 1, wherein an electromagnetic shield layer is added between the cavities on both sides of the ceramic laminated substrate and between the semiconductor elements in the same cavity.