Plastic-packaged semiconductor device having a heat sink matched with a plastic package

A plastic-packaged semiconductor device having a heat sink, a semiconductor chip on said heat sink, and a plastic package which has a predetermined thermal expansion coefficient and a predetermined thermal conductivity and which covers said heat sink and said semiconductor chip, wherein said heat sink comprises a composite block comprising:

• a metal plate of a first metal having a density lower than that of copper;
• and
• a mesh member which has a predetermined mesh size and which is buried in said first metal, said mesh member being formed by a second metal having a density heavier than that of copper;
• said composite block having a thermal expansion coefficient and a thermal conductivity which are selected in relation to said predetermined thermal expansion coefficient and said predetermined thermal conductivity of said plastic package, and wherein said thermal expansion coefficient of said composite block is between 9.0.times.10.sup.-6 /K and 23.0.times.10.sup.-6 /K and said thermal conductivity of said composite block is not lower than 200 W/m.multidot.K.

A plastic-packaged semiconductor device having a heat sink, a semiconductor chip on said heat sink, and a plastic package which has a predetermined thermal expansion coefficient and a predetermined thermal conductivity and which covers said heat sink and said semiconductor chip, wherein said heat sink is formed by a stacked sheet comprising:

• a sintered sheet which comprises a mixture of a first metal of a first melting point and a second metal of a second melting point lower than said first melting point and which has front and back surfaces opposite to each other and a side surface contiguous to said front and back surfaces;
• and
• a coated layer which is coated on at least said front and said back surfaces of the sintered sheet and which is composed of a selected one of said first and said second metals;
• said stacked sheet having a thermal expansion coefficient and a thermal conductivity which are selected in relation to said predetermined thermal expansion coefficient and said predetermined thermal conductivity of said plastic package, and wherein said thermal expansion coefficient of said stacked sheet is between 9.0.times.10.sup.-6 /K and 23.0.times.10.sup.-6 /K and said thermal conductivity of said stacked sheet is not lower than 200 W/m.multidot.K.

A plastic-packaged semiconductor device having a heat sink, said device comprising a heat sink, a semiconductor chip on said heat sink, and a plastic package which has a predetermined thermal expansion coefficient and a predetermined thermal conductivity and which covers said heat sink and said semiconductor chip, wherein said heat sink is formed by a stacked sheet comprising:

• an aluminum sheet having front and back surfaces opposite to each other;
• a first molybdenum sheet attached to said front surface of the aluminum sheet;
• and
• a second molybdenum sheet attached to said back surface of the aluminum sheet;
• said stacked sheet having a thermal expansion coefficient and a thermal conductivity which are selected in relation to said predetermined thermal expansion coefficient and said predetermined thermal conductivity of said plastic package, and wherein said thermal expansion coefficient of said stacked sheet is between 9.0.times.10.sup.-6 /K and 23.0.times.10.sup.-6 /K and said thermal conductivity of said stacked sheet is not lower than 200 W/m.multidot.K.

A heat sink for use in a semiconductor device of a transfer molded type which comprises a heat sink, a semiconductor chip transfer molded by a resin, and a plastic package which has a predetermined thermal expansion coefficient and a predetermined thermal conductivity and which covers said heat sink and said semiconductor chip, wherein said heat sink comprises:

• a substrate formed by a metal composite material which comprises a mixture of:
• a first metal component of a high refractory metal having a first melting point;
• and
• a second metal component having a second melting point lower than said first melting point;
• said substrate having a thermal expansion coefficient and a thermal conductivity which are selected in relation to said predetermined thermal expansion coefficient and said predetermined thermal conductivity of said plastic package, and wherein said thermal expansion coefficient of said substrate is between 9.0.times.10.sup.-6 /K and 23.0.times.10.sup.-6 /K and said thermal conductivity of said substrate is not lower than 200 W/m.multidot.K.

A plastic package having a heat sink, wherein said plastic package has a predetermined thermal expansion coefficient and a predetermined thermal conductivity, and wherein said heat sink comprises:

• a substrate formed by a metal composite material which comprises a mixture of:
• a first metal component of a high refractory metal having a first melting point;
• and
• a second metal component having a second melting point lower than said first melting point;
• said substrate having a thermal expansion coefficient and a thermal conductivity which are selected in relation to said predetermined thermal expansion coefficient and said predetermined thermal conductivity of said plastic package, and wherein said thermal expansion coefficient of said substrate is between 9.0.times.10.sup.-6 /K and 23.0.times.10.sup.-6 /K and said thermal conductivity of said substrate is not lower than 200 W/m.multidot.K.