Multi-chip stacked devices

A multi-chip device comprising:

• a chip stack comprising:
• a base chip having a first plurality of front side bond pads;
• and
• a plurality of interchangeable chips comprising:
• a first chip of the plurality of interchangeable chips having a second plurality of front side bond pads, and a first plurality of backside bond pads;
• a second chip of the plurality of interchangeable chips having a third plurality of front side bond pads, and a second plurality of backside bond pads, wherein, the base chip being directly bonded to the first chip of the plurality of interchangeable chips, each neighboring pair of the plurality of interchangeable chips being directly bonded together in an orientation with a front side of one chip of the respective neighboring pair directly bonded to a backside of the other chip of the respective neighboring pair, each of the interchangeable chips having a same processing integrated circuit and a same hardware layout, and wherein a first front side bond pad of the first plurality of front side bond pads on the base chip is bonded to a first front side bond pad of the second plurality of front side bond pads on the first chip of the plurality of interchangeable chips, and a third front side bond pad of the third plurality of front side bond pads on the second chip of the plurality of interchangeable chips is bonded to a first backside bond pad of the first plurality of backside bond pads of the first chip of the plurality of interchangeable chips, wherein the first chip of the plurality of interchangeable chips includes metal bond pads at a surface directly bonded to the base chip, at least some of the metal bond pads not being electrically connected to an integrated circuit of the base chip.

A method of forming different multi-chip devices, the method comprising:

• performing front side processing for a first base chip on a first wafer, the first base chip having a first plurality of front side bond pads;
• performing front side processing for a second base chip having a second plurality of front side bond pads, the second base chip disposed on a second wafer, the first base chip having a different hardware architecture from the second base chip;
• performing front side processing for a first active chip having a third plurality of front side bond pads and a plurality of backside bond pads on each of third wafers, each of the first active chips of the third wafers having a same processing integrated circuit having a same hardware architecture;
• forming a first multi-chip device comprising bonding the first wafer to a first wafer of the third wafers, the first base chip being directly bonded and electrically connected to the first active chip of the first wafer of the third wafers, wherein a first front side bond pad of the first plurality of front side bond pads on the first base chip is bonded to a first front side bond pad, or is bonded to a first backside bond pad, of the third plurality of front side bond pads, on the first active chip of each of the third wafers;
• and
• forming a second multi-chip device different from the first multi-chip device, forming the second multi-chip device comprising bonding the second wafer to a second one of the third wafers, the second base chip being directly bonded and electrically connected to the first active chip of the second one of the third wafers, and wherein a first front side bond pad of the first plurality of front side bond pads on the second base chip is bonded to a first front side bond pad, or is bonded to a first backside bond pad, of the third plurality of front side bond pads, on the first active chip of each of the third wafers, wherein the first active chip includes metal bond pads at a surface directly bonded to the first base chip, at least some of the metal bond pads not being electrically connected to an integrated circuit of the first base chip.