Semiconductor package
Semiconductor packages are provided to prevent a chip, such as a central processing unit (CPU) chip, from being degraded due to hot spot heat generated during the operation of the chip and absorbs thermomechanical stresses in interfaces between the chip, a thermal interface material (TIM) and a lid. The chip is electrically connected, e.g., flip-chip bonded, to a package substrate. The lid is thermally connected to and disposed over a back surface of the chip with the TIM interposed therebetween. A heat dissipation means adjacent the TIM is also located between the lid and the chip to prevent the hot spot effect.
1. A semiconductor package comprising:
a chip having an active surface and an outside surface, the chip having a plurality of electrode bumps formed on the active surface thereof;
a package substrate having an upper surface and a lower surface opposite the upper surface, the chip being electrically connected to the upper surface of the substrate;
a lid thermally connected to and disposed over the upper surface of the chip for emitting heat generated from the chip;
a thermal interface material (TIM) comprising solder formed on the upper surface of the chip for transferring heat generated from the chip to the lid;
one of a heat dissipation layer and an under barrier metal (UBM) formed on the upper surface of the TIM and having a surface area that is at least double the outside surface area of the chip; and
the other of the heat dissipation layer and UBM formed adjacent the lower surface of the lid.
2. The semiconductor package of claim 1 , wherein the lid is made of aluminum and the UBM is formed by anodizing, followed by sputtering or evaporation.
3. The semiconductor package of claim 1 , wherein the lid is made of Cu, CuW, AlSiC or CuMo and the UBM is formed by a plating method.
4. The semiconductor package of claim 1 , further comprising external connection terminals extending from the lower surface of the substrate and electrically connected to the chip.
5. The semiconductor package of claim 1 , wherein the chip is electrically connected to the substrate using a flip chip technology.
6. The semiconductor package of claim 1 , wherein the heat dissipation layer has a thermal conductivity of about 1000 W/mk or more and comprises a material having a coefficient of thermal expansion of about 4.0 or less.
7. The semiconductor package of claim 1 wherein the TIM is between the chip and the heat dissipation layer.