Patent ID: 7902663

Claim:
A semiconductor package primarily comprising: a substrate having a covered surface and an exposed surface, wherein the covered surface includes a die-attaching area, the substrate being a printed circuit board; a die-attaching material formed on the covered surface of the substrate; a chip aligned with the die-attaching area and attached to the covered surface of the substrate by the die-attaching material; a first row of ball terminals disposed on the exposed surface of the substrate; and a second row of ball terminals disposed on the exposed surface of the substrate, wherein the second row of ball terminals are relatively away from a central line of the die-attaching area than the first row of ball terminals; wherein the substrate further has at least a stepwise depression formed on the covered surface to make a thickness of the substrate from the covered surface to the exposed surface be stepwise decreased from the central line of the die-attaching area toward two opposing sides of the substrate; wherein the stepwise depression is a groove for accommodating the die-attaching material; wherein the die-attaching material is filled in the stepwise depression; wherein the substrate has a first decreased thickness measured from the first row of ball terminals to a first step of the stepwise depression and a second decreased thickness measured from the second row of ball terminals to a second step of the stepwise depression, wherein the second decreased thickness is smaller than the first decreased thickness; wherein the chip has a cross-sectional corner in contact with the die-attaching material approximately parallel to a disposing direction of the second row of ball terminals, wherein the stepwise depression has a groove edge located outside the die-attaching area and adjacent to the cross-sectional corner.