Stack packages having token ring loops

1. A stack package comprising:

a substrate having a first bond finger, a second bond finger and a third bond finger;

a first semiconductor chip group including a plurality first semiconductor chips stacked on the substrate and a second semiconductor chip group including a plurality of second semiconductor chips stacked on the first semiconductor chip group, each of the first semiconductor chips and the second semiconductor chips having an input bonding pad, an output bonding pad and a dummy pad;

a first token ring loop including a first interconnection electrically connect the first bond finger of the substrate to the input bonding pad of a lowermost first semiconductor chip of the first semiconductor chips, a second interconnection to electrically connect the output bonding pad of a lower first semiconductor chip of the first semiconductor chips to the input bonding pad of an upper first semiconductor chip stacked on the lower first semiconductor chip, a third interconnection to electrically connect the output bonding pad of an upper first semiconductor chip of the first semiconductor chips to the dummy pad of a lower first semiconductor chip under the upper first semiconductor chip, and a fourth interconnection to electrically connect the dummy pad of a lowermost first semiconductor chip of the first semiconductor chips to the second bond finger of the substrate; and

a second token ring loop including a first interconnection to electrically connect the second bond finger of the substrate to the input bonding pad of a lowermost second semiconductor chip of the second semiconductor chips, a second interconnection to electrically connect the output bonding pad of a lower second semiconductor chip of the second semiconductor chips to the input bonding pad of an upper second semiconductor chip stacked on the lower second semiconductor chip, a third interconnection to electrically connect the output bonding pad of an upper second semiconductor chip of the second semiconductor chips to the dummy pad of a lower second semiconductor chip under the upper second semiconductor chip, and a fourth interconnection to electrically connect the dummy pad of a lowermost second semiconductor chip of the second semiconductor chips to the third bond finger of the substrate.

2. The stack package of claim 1 , wherein the first semiconductor chips of the first semiconductor chip group and the second semiconductor chips of the second semiconductor chip group are stacked in the same direction to have a step structure to expose the input bonding pads, the output bonding pads, and the dummy pads of the first and second semiconductor chips.

3. The stack package of claim 1 , wherein the first and third bond fingers act as an input terminal and an output terminal, respectively.

4. The stack package of claim 1 , wherein the input bonding pad and the output bonding pad of each of the first and second semiconductor chips are connected to each other through an internal circuit integrated in the corresponding semiconductor chip.

5. A stack package comprising:

a substrate having a first bond finger group and a second bond finger group, each including a first bond finger, a second bond finger and a third bond finger;

first semiconductor chip groups and second semiconductor chip groups alternately and repeatedly stacked on the substrate, and each of the first and second semiconductor chips having an input bonding pad, an output bonding pad and a dummy pad;

a first group of first token ring loop including a first interconnection to electrically connect the first bond finger of the first bond finger group to the input bonding pad of a lowermost first semiconductor chip in a lower group of the first semiconductor chip groups, a second interconnection to electrically connect the output bonding pad of the lowermost first semiconductor chip in the lower group of the first semiconductor chip groups to the input bonding pad of an upper first semiconductor chip on the lowermost first semiconductor chip, a third interconnection to electrically connect the output bonding pad of the upper first semiconductor chip to the dummy pad of a lower first semiconductor chip under the upper first semiconductor chip, and a fourth interconnection to electrically connect the dummy pad of the lowermost first semiconductor chip to the second bond finger of the first bond finger group; and

a first group of second token ring loop including a first interconnection to electrically connect the second bond finger of the first bond finger group to the input bonding pad of a lowermost first semiconductor chip in an upper group of the first semiconductor chip groups, a second interconnection to electrically connect the output bonding pad of the lowermost first semiconductor chip in the upper group of the first semiconductor chip groups to the input bonding pad of an upper first semiconductor chip on the lowermost first semiconductor chip, a third interconnection to electrically connect the output bonding pad of the upper first semiconductor chip to the dummy pad of a lower first semiconductor chip under the upper first semiconductor chip, and a fourth interconnection to electrically connect the dummy pad of the lowermost first semiconductor chip to the third bond finger of the first bond finger group.

6. The stack package according to claim 5 , further comprising:

a second group of first token ring loop including a first interconnection to electrically connect the first bond finger of the second bond finger group to the input bonding pad of a lowermost second semiconductor chip in a lower group of the second semiconductor chip groups, a second interconnection to electrically connect the output bonding pad of the lowermost second semiconductor chip in the lower group of the second semiconductor chip groups to the input bonding pad of an upper second semiconductor chip on the lowermost second semiconductor chip, a third interconnection to electrically connect the output bonding pad of the upper second semiconductor chip to the dummy pad of a lower second semiconductor chip under the upper second semiconductor chip, and a fourth interconnection to electrically connect the dummy pad of the lowermost second semiconductor chip to the second bond finger of the second bond finger group; and

a second group of second token ring loop including a first interconnection to electrically connect the second bond finger of the second bond finger group to the input bonding pad of a lowermost second semiconductor chip in an upper group of the second semiconductor chip groups, a second interconnection to electrically connect the output bonding pad of the lowermost second semiconductor chip in the upper group of the second semiconductor chip groups to the input bonding pad of an upper second semiconductor chip on the lowermost second semiconductor chip, a third interconnection to electrically connect the output bonding pad of the upper second semiconductor chip to the dummy pad of a lower second semiconductor chip under the upper second semiconductor chip, and a fourth interconnection to electrically connect the dummy pad of the lowermost second semiconductor chip to the third bond finger of the second bond finger group.

7. The stack package of claim 5 :

wherein the first semiconductor chips of the first semiconductor chip groups are stacked in a first direction to have a step structure;

wherein the second semiconductor chips of the second semiconductor chip groups are stacked in a second direction to have a step structure that is opposite to the first direction of the first semiconductor chips.

8. The stack package of claim 5 , wherein the first bond fingers of the first and second bond finger groups act as input terminals and the third bond fingers of the first and second bond finger groups act as output terminals.

9. The stack package of claim 5 , wherein the input bonding pad and the output bonding pad of each of the first and second semiconductor chips are connected to each other through an internal circuit integrated in the corresponding semiconductor chip.

10. The stack package of claim 5 , wherein the first semiconductor chips of the first semiconductor chip groups are stacked in a first direction to have a step structure to expose the input bonding pads, the output bonding pads and the dummy pads of the first semiconductor chips.

11. The stack package of claim 10 , wherein the second semiconductor chips of the second semiconductor chip groups are stacked in a second direction to have a step structure to expose the input bonding pads, the output bonding pads and the dummy pads of the second semiconductor chips.