Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – Insulating material
Patent
1998-05-19
2000-03-14
Thomas, Tom
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
Insulating material
257701, 257689, H01L 23053, H01L 2312, H01L 2348
Patent
active
060376570
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to the field of semiconductor devices for mounting semiconductor elements on circuit boards.
BACKGROUND OF THE INVENTION
A semiconductor device of the prior art is explained with reference to drawings.
In FIG. 8. a semiconductor device 1 consists of a semiconductor element 2 disposed on a carrier 3 made of insulating material. A plurality of electrodes 6 soldered or bonded with a gold bump 5 to electrodes 4 of the semiconductor element 2 are disposed on the top face of the carrier 3, and external electrode terminals 8 are aligned in a matrix on the bottom face of the carrier 3. The electrodes 6 are electrically coupled to external electrode terminals 8. The space between the semiconductor element 2 and carrier 3. and around the semiconductor element 2 are filled and covered with epoxy resin sealant 7. Solder bumps 9 may in some cases be formed on the surface of the external electrode terminals 8. In FIG. 8, the semiconductor device is mounted on a circuit board 12. Electrodes 11 are disposed in the matrix on the circuit board 12 in an area where the semiconductor device 1 will be mounted, corresponding to the external electrode terminals 8. Solder paste 13 is printed on the matrix electrodes 11. As shown in FIG. 9, the semiconductor device 1 is placed on the circuit board 12 so as to allow the external electrode terminals 8 of the semiconductor device 1 to make contact with the electrodes 11 of the circuit board 12. The external electrode terminals 8 and electrodes 11 are bonded with solder 10 by heating and melting the solder paste 13.
The design of the semiconductor device 1 as configured above makes it difficult to adjust the height H between the carrier 3 and circuit board 12, as shown in FIG. 9, when mounting the semiconductor device 1 onto the circuit board 12. If the height H is short, thermal stress generated by the difference in thermal expansion coefficient of the carrier 3 and circuit board 12 is concentrated on the soldered portion, causing cracks in soldered portions or peeling in some cases.
DISCLOSURE OF THE INVENTION
The present invention offers a semiconductor device which can be mounted on a printed circuit board with high reliability, and a mounting method for such semiconductor devices.
In the semiconductor device of the present invention, output electrodes formed on the surface of semiconductor elements which forms an integrated circuit is connected to a conductive circuit formed on a carrier for semiconductor for enabling electrical coupling with an external material using external electrodes formed on the carrier for semiconductor. The external electrodes are disposed on a bottom surface of cavity areas provided in the carrier for semiconductor.
The carrier for semiconductor has a multi-layer structure from the upper part to the lower part protruding to the bottom face, In the thickness direction of the semiconductor device, for forming the concave portion with the upper part of the flat board. Materials used for forming the multi-layer structure has different thermal expansion coefficients which bridge the thermal expansion coefficient of the carrier for semiconductor of the semiconductor device to the circuit board on which the semiconductor device is mounted.
A method for mounting the semiconductor device comprises the dispensing of solder paste to the concave portion of the external electrode of the semiconductor device, flipping of the semiconductor device, mounting of the semiconductor device onto the circuit board, and soldering by heating the circuit board. Another method comprises application of adhesive flux to the concave portion of the external electrode of the semiconductor device, supplying of solder balls on top of the adhesive flux applied, flipping of the semiconductor device, mounting of the semiconductor device onto the circuit board, and soldering by heating the circuit board. Still another method comprises application of adhesive to an area where electrical coupling is not required but the semiconductor
REFERENCES:
patent: 4999700 (1991-03-01), Dunaway et al.
patent: 5168344 (1992-12-01), Ehlert et al.
patent: 5841194 (1998-11-01), Tsukamoto
Tsurumi Koichi
Yamamoto Ken-ichi
Matsushita Electric - Industrial Co., Ltd.
Nadav Ori
Thomas Tom
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