Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – With stress relief
Reexamination Certificate
1999-03-26
2001-11-27
Abraham, Fetsum (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
With stress relief
C257S670000, C257S417000, C257S418000, C257S419000, C257S420000
Reexamination Certificate
active
06323542
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a compact electronic component and a semiconductor device whose final formed package size is close to the size of the chip (semiconductor element), to methods of manufacturing these, to a circuit board on which these are mounted, and to an electronic instrument having this circuit board.
BACKGROUND ART
To pursue high density mounting in semiconductor devices, bare chip mounting is the ideal. However, quality control and handling of bare chips are difficult. For this reason, CSP (chip size/scale package) technology, in which the package size is close to the chip size, has been developed.
In such a CSP semiconductor device, an important problem is to relieve the thermal stress due to the differences in coefficient of thermal expansion between the semiconductor chip and the mounting board. In particular, as the number of pins continues to increase, it is essential that no wiring breaks are caused by thermal stress, since wiring is required to connect from the electrodes to the solder balls.
The present invention addresses the above described problems, and has as its object the provision of an electronic component, a semiconductor device, methods of manufacturing theses a circuit board on which these are mounted, and an electronic instrument having this circuit board.
DISCLOSURE OF THE INVENTION
The semiconductor device of the present invention comprises a semiconductor element, an external electrode provided within the region of the semiconductor element for external connection, wiring connected through a connection portion to the external electrode and electrically connecting the semiconductor element and the external electrode, a stress relieving portion provided on the semiconductor element, and a stress transmission portion transmitting stress from the external electrode to the stress relieving portion.
Since the semiconductor element and external electrode of the present invention are connected by the wiring, the pitch of external electrode can be converted as required. The stress transmission portion transmits stress from the external electrode to the stress relieving portion, and stress can be thus relieved.
The wiring is connected to the external electrode through a connection portion. The connection portion is not restricted to the case of existing as a separate member between the wiring and the external electrode, but includes the case of being a part of at least one of the wiring and external electrode. The connection portion is not restricted to directly contacting at least one of the wiring and external electrode, but includes the case of not directly contacting either. That is to say, the connection portion of the present invention indicates at least a part of the member electrically connecting the wiring and external electrode.
More specifically, the wiring may be provided on the stress relieving portion, and the stress transmission portion may be provided in the connection portion.
By this means, since the wiring is provided on the stress relieving portion, the connection portion and stress transmission portion are provided on the stress relieving portion, and the stress from the external electrode is transmitted to the stress relieving portion.
Alternatively, the wiring may be provided under the stress relieving portion, the connection portion may be provided to pass through the stress relieving portion, and the stress transmission portion may be formed on the stress relieving portion integrally with the connection portion.
By this means, since the connection portion passes through the stress relieving portion, the connection portion does not transmit stress vertically to the stress relieving portion. In place of this, the stress transmission portion provided on the stress relieving portion transmits stress to the stress relieving portion.
The stress relieving portion may be formed with a thickness to reach the stress transmission portion from the wiring.
The stress relieving portion may have a groove formed outside of the stress transmission portion. By forming a groove, the stress relieving portion is more easily deformed, and stress from the stress transmission portion can be absorbed more easily.
The stress relieving portion may have a space formed between a contact position on the wiring and a contact position under the stress transmission portion. By this means, the stress relieving portion is more easily able to deform, and stress from the stress transmission portion can be absorbed more easily.
A stress relieving portion having such a space may be formed with a thickness to reach the stress transmission portion from the wiring, and then may be etched from the outside of the stress transmission portion to underneath thereof.
The present invention may further comprise a supplementary transmission portion provided at least between a root periphery of the external electrode and the stress relieving portion, and transmitting stress from the external electrode to the stress relieving portion.
By means of the supplementary transmission portion, stress from the external electrode is transmitted to the stress relieving portion, and a concentration of stress between the external electrode and the stress transmission portion can be prevented.
The supplementary transmission portion may be formed of a material capable of being used for the stress relieving portion.
The stress relieving portion may include a first stress relieving layer and a second stress relieving layer formed on the first stress relieving layer;
the wiring may be provided between the first and second stress relieving layers;
the connection portion may be provided to penetrate the second stress relieving layer; and
the stress transmission portion may be formed on the second stress relieving layer integrally with the connection portion.
By this means, the connection portion transmits stress in the vertical direction to the first stress relieving layer. Meanwhile, the stress transmission portion transmits stress to the second stress relieving layer. In this way, stress is relieved at two locations.
The stress relieving portion may include a first stress relieving layer and a second stress relieving layer formed on the first stress relieving layer;
the wiring may be provided between the first and second stress relieving layers;
the connection portion may be provided to penetrate the second stress relieving layer; and
the stress transmission portion may include a first transmission portion formed between the first and second stress relieving layers integrally with the connection portion, and a second transmission portion formed on the second stress relieving layer integrally with the connection portion.
The connection portion transmits stress in the vertical direction to the first stress relieving layer. Stress is also transmitted to the first stress relieving layer from the first transmission portion of the stress transmission portion Furthermore, the stress transmission portion has a second stress transmission portion, and this second stress transmission portion transmits stress to the second stress relieving layer. In this way, stress is relieved at three locations.
It is preferable that the second transmission portion has a larger area than the first transmission portion, and transmits the stress to the second stress relieving layer.
Since the second transmission portion transmits a large amount of stress, the stress transmitted by the first transmission portion is comparatively small. The first transmission portion is close to the direct contact portion of the connection portion and wiring. Therefore, by reducing the stress transmitted from the first transmission portion, the effect on this contact portion can be reduced.
It is preferable that the stress transmission portion is provided without contacting the connection portion.
By this means, the stress transmission portion does not transfer stress to the direct contact portion of the connection portion and wiring.
The stress relieving portion may have an isolation portion for inhibiting transmissio
Abraham Fetsum
Oliff & Berridg,e PLC
Seiko Epson Corporation
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