Sumitomo Bakelite Company Limited

Hideki Hara

Mitsuo Sugino

Toru Meura

Hitoshi Aoki

Kensuke Nakamura

Takeshi Hosomi

Masaaki Kato

A semiconductor element mounting board includes: a board having surfaces; a semiconductor element provided at a side of one of the surfaces of the board; a bonding agent layer through which the board and the semiconductor element are bonded together, the bonding agent layer having a storage modulus at 25&#xb0; C. of 5 to 1,000 MPa; a first layer into which the semiconductor element is embedded, the first layer provided on the one surface of the board; a second layer provided on the other surface of the board, the second layer being constituted from the same material as that of the first layer, the constituent material of the second layer having the same composition ratio as that of the constituent material of the first layer; and surface layers provided on the first and second layers, respectively, each of the surface layers being formed from at least a single layer. In the semiconductor element mounting board, a coefficient of thermal expansion of each surface layer in an inplane direction thereof measured based on JIS C 6481 at a temperature of 20&#xb0; C. to a glass-transition temperature Tg&#xb0; C., which is measured based on JIS C 6481, is 40 ppm/&#xb0; C. or lower.

Semiconductor element mounting board

A semiconductor element mounting board includes: aboard having surfaces; a semiconductor element mounted on one of the surfaces of the board; a first layer into which the semiconductor element is embedded, the first layer being provided on the one surface of the board; a second layer provided on the other surface of the board, the second layer being constituted from the same material as that of the first layer, the constituent material of the second layer having the same composition ratio as that of the constituent material of the first layer; and surface layers provided on the first and second layers, respectively, each of the surface layers being formed from at least a single layer. In such a semiconductor element mounting board, each of the surface layers has rigidity higher than that of each of the first and second layers. It is preferred that in the case where a Young's modulus of each surface layer at 25&#xb0; C. is defined as X GPa and a Young's modulus of the first layer at 25&#xb0; C. is defined as Y GPa, the X and the Y satisfy a relation of 0.5&#x2266;X&#x2212;Y&#x2266;13.

The invention relates to a low-cost transfer bump sheet which is capable of transferring copper-cored solder bumps with high reliability of bonding to a semiconductor chip and which is capable of transferring bumps of various structures. The invention also relates to a low-cost semiconductor flip chip in which copper-cored solder bumps with high reliability of bonding are mounted on a semiconductor chip through the use of the transfer bump sheet. In the transfer bump sheet, metal posts of two or more layers are formed on a base sheet. The invention also relates to a method of manufacturing this semiconductor flip chip, which comprises the steps of forming the base sheet on a metal foil, forming a plating mask on the metal foil, forming a first solder layer (solder coating) on the metal foil by electrolytic plating or electroless plating, removing the plating mask, and forming a metal layer (metal core) of metal posts by the etching of the metal foil through the use of the formed first solder layer (solder coating) as an etching mask.

Growing community of inventors

Utsunomiya, Japan

Hideki Hara