Semiconductor chip and production thereof, and semiconductor device having semiconductor chip bonded to solid device
A semiconductor chip having a functional bump provided on a surface of a semiconductor substrate thereof for electrical connection between an internal circuit thereof and a solid device, and a dummy bump not serving for the electrical connection between the internal circuit and the solid device. The dummy bump may be a stress relieving bump for relieving stresses exerted thereon. The dummy bump may be connected to a low impedance portion. The functional bump and the dummy bump may be provided on a surface protective film. In this case, the dummy bump is provided on a recess formed in the surface protective film.
1. A semiconductor device, comprising:
primary semiconductor chip;
a secondary semiconductor chip face-down-bonded onto a surface of the primary semiconductor chip to form a chip-on-chip structure;
a package that packages the chip-on-chip structure;
a primary functional bump formed on the surface of the primary semiconductor chip, for electrical connection between internal circuits of the primary and secondary semiconductor chips;
a primary dummy bump, formed on the surface of the primary semiconductor chip, not serving for electrical connection between the internal circuits, the primary dummy bump having a height that is substantially equal to a height of the primary functional bump;
a secondary functional bump disposed in association with a peripheral portion of a mating surface of the primary semiconductor chip opposed to the primary semiconductor chip, for electrical connection between the internal circuits; and
a secondary dummy bump, disposed in association with a central portion of the mating surface, not serving for electrical connection between the internal circuits but serving for absorption of a force exerted on the secondary semiconductor chip, the secondary dummy bump having a height that is substantially equal to a height of the secondary functional bump;
the primary and secondary functional bumps being joined to each other, thereby electrically connecting the primary and secondary semiconductor chips,
the primary and secondary dummy bumps being joined to each other over an area of contact extending over an entire active region of the mating surface of the secondary semiconductor chip.
2. The semiconductor device according to claim 1 wherein the area over which the primary and secondary dummy bumps are joined to each other is greater than an area over which of the primary and secondary functional bumps are joined to each other.
3. The semiconductor device according to claim 1 , wherein at least one of the primary and secondary semiconductor chips includes a low impedance portion and the primary and secondary dummy bumps are electrically connected to the low impedance portion.