Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead – Die bond
Reexamination Certificate
1998-09-22
2001-10-09
Thomas, Tom (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
Die bond
C257S781000, C257S789000, C257S795000
Reexamination Certificate
active
06300686
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to semiconductor packages used for various kinds of electric and electronic devices and a method for manufacturing the same and more particularly to a semiconductor package that is the same size as a semiconductor chip and is excellent in heat dissipation and a method for manufacturing the same.
BACKGROUND OF THE INVENTION
In recent years, integration of semiconductor chips has become denser, and the functions of semiconductor chips have become ever more advanced. Consequently, the size of semiconductor chips and the number of electrodes on the semiconductor chip have become remarkable. On the other hand, it is required for a semiconductor package to be miniaturized to meet the demand for highly efficient and miniaturized electronic devices. Under these circumstances, a semiconductor package has shifted from the QFP (Quad Flat Package) type that is a semiconductor package having leads that are arranged around the peripheral part of the package to the BGA (Ball Grid Array) type that is a semiconductor package having electrodes arranged in area array on a bottom surface and the CSP (Chip Scale Package) type that is a semiconductor package that is further miniaturized.
FIG. 10
is a cross-sectional view showing the configuration of the CSP type semiconductor package. As shown in
FIG. 10
, bumps
102
are formed on electrodes formed on a semiconductor chip
101
, the semiconductor chip
101
having connected to electrodes
104
formed on a wiring substrate
105
with face down via conductive resin
103
. Further, sealing resin
107
is filled between the semiconductor chip
101
and the wiring substrate
105
to ensure the air-tightness. In
FIG. 10
, numeral
106
indicates an external lead electrode.
When the CSP type semiconductor package is used, an area of a circuit board can be utilized efficiently by miniaturizing the package. Thereby the package can be suitable for high speed and low noise circuits.
However, the above-mentioned conventional CSP type semiconductor package has the following problems. That is, when reliability such as thermal shock is evaluated, a sealing part between a semiconductor chip and a wiring substrate is prone to the cracking, because the thermal expansion coefficient of the semiconductor chip and that of the wiring substrate are different, and as a result, the air-tightness might deteriorate. Further, the cost and the number of steps of manufacturing may be increased by performing a process for sealing resin and coating. Further, the thermal conductivity between the semiconductor chip and the wiring substrate is very poor and it is very difficult for heat that is generated in the semiconductor chip to be released.
SUMMARY OF THE INVENTION
The present invention aims to solve the above-mentioned subjects and provide a semiconductor package which is not required to be sealed by resin, is excellent in reliability, air-tightness and thermal conductivity, and can be manufactured at low cost easily, and a method of manufacturing the same.
To accomplish the above-mentioned object, a first configuration of a semiconductor package according to the present invention comprises a semiconductor chip, a thermal conductive mixture including at least 70-96 weight parts of inorganic filler and 5-30 weight parts of thermosetting resin composition that is bonded to an electrode surface of the semiconductor chip where electrodes are formed and to edge surfaces of the semiconductor chip that adjoin the electrode surfaces, and an external lead electrode that is formed on the thermal conductive mixture and is electrically connected with the semiconductor chip.
According to a first configuration of the semiconductor package, it is not required to provide a further resin seal for a semiconductor chip using a thermal conductive mixture as a substrate and a semiconductor package excellent in thermal conductivity can be realized. Further, the thermal expansion coefficient of a thermal conductive mixture as a substrate in the in-plane direction is almost the same as that of a semiconductor chip. Therefore even after a reflow test is conducted, an abnormality in the interface of the semiconductor chip and the package is not observed particularly, and the electrical resistance value of the semiconductor package including a part connecting the semiconductor chip and an external lead electrode changes only very slightly. As a result, a semiconductor package excellent in reliability can be realized.
In a first configuration of the semiconductor package, it is preferable that a through-hole is formed in a thermal conductive mixture opposing to an electrode formed on a semiconductor chip.
Further, in this case, it is preferable that a conductive resin composition is filled in a through-hole and an external lead electrode is connected electrically with a semiconductor chip via the conductive resin composition. In this case, it is preferable that a conductive resin composition includes at least thermosetting resin, a curing agent and at least one kind of metallic powder selected from a group consisting of gold, silver, copper, palladium and nickel.
In a first configuration of the semiconductor package, it is preferable that a bump is formed on an electrode formed on a semiconductor chip. According to this preferable example, reliability in electrically connecting the semiconductor chip with an external lead electrode can be improved. Further, in this case, it is preferable that the bump penetrates into a thermal conductive mixture and is integrated with the external lead electrode.
In a first configuration of the semiconductor package, it is preferable that the inorganic filler includes at least one selected from a group consisting of Al
2
O
3
, MgO, BN and AlN. This is because they have high thermal conductivity.
In a first configuration of the semiconductor package, it is preferable that the inorganic filler has a particle diameter in a range between 0.1-100 &mgr;m.
In a first configuration of the semiconductor package, it is preferable that a thermosetting resin composition includes at least one kind of resin as a main component selected from a group consisting of epoxy resin, phenol resin and cyanate resin. This is because they are excellent in electric property and in mechanical property.
In a first configuration of the semiconductor package, it is preferable that a thermosetting resin composition includes brominated multi-functional epoxy resin as a main component and further includes novolak resin of bisphenol A as a curing agent and imidazole as a curing promoter.
In a first configuration of the semiconductor package, it is preferable that a thermal conductive mixture includes at least one kind selected from a group consisting of a coupling agent, a dispersing agent, a coloring agent and a mold-releasing agent.
To accomplish the above-mentioned object, a second configuration of a semiconductor package according to the present invention comprises a semiconductor chip, a thermal conductive mixture including at least 70-95 weight parts of inorganic filler and 5-30 weight parts of thermosetting resin composition that is bonded to an electrode surface of the semiconductor chip where electrodes are formed and to edge surfaces of the semiconductor chip that adjoin the electrode surface, and a wiring substrate having electrodes formed on both surfaces that is bonded to the thermal conductive mixture, and the electrodes formed on one surface of the wiring substrate are electrically connected with the semiconductor chip and the electrodes formed on another surface serve as an external electrode.
According to the second configuration of the semiconductor package, the spacing and the arrangement of the external lead electrodes can be changed by providing a wiring substrate and it becomes easy for a semiconductor package to be mounted on electronic devices.
In a second configuration of the semiconductor package, it is preferable that a main component of a wiring substrate is the same as that of a thermal conductive mixture. According to
Hirano Koichi
Nakatani Seiichi
Chambliss Alonzo
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P,C,
Thomas Tom
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