In one aspect, an active electronically scanned array (AESA) tile includes a radiator structure and oxide-bonded semiconductor wafers attached to the radiator structure and comprising a radio frequency (RF) manifold and a beam former. An RF signal path through the oxide-bonded wafers comprises a first portion that propagates toward the beam former and a second portion that propagates parallel to the beam former.

In one aspect, an active electronically scanned array (AESA) tile includes a radiator structure and oxide-bonded semiconductor wafers attached to the radiator structure and comprising a radio frequency (RF) manifold and a beam former. An RF signal path through the oxide-bonded wafers comprises a first portion that propagates toward the beam former and a second portion that propagates parallel to the beam former.

A method includes bonding a first device die with a second device die. The second device die is over the first device die. A passive device is formed in a combined structure including the first and the second device dies. The passive device includes a first and a second end. A gap-filling material is formed over the first device die, with the gap-filling material including portions on opposite sides of the second device die. The method further includes performing a planarization to reveal the second device die, with a remaining portion of the gap-filling material forming an isolation region, forming a first and a second through-vias penetrating through the isolation region to electrically couple to the first device die, and forming a first and a second electrical connectors electrically coupling to the first end and the second end of the passive device.

A method includes bonding a first device die with a second device die. The second device die is over the first device die. A passive device is formed in a combined structure including the first and the second device dies. The passive device includes a first and a second end. A gap-filling material is formed over the first device die, with the gap-filling material including portions on opposite sides of the second device die. The method further includes performing a planarization to reveal the second device die, with a remaining portion of the gap-filling material forming an isolation region, forming a first and a second through-vias penetrating through the isolation region to electrically couple to the first device die, and forming a first and a second electrical connectors electrically coupling to the first end and the second end of the passive device.

Three-dimensional integrated circuit structures are disclosed. A three-dimensional integrated circuit structure includes a first die, a second die and a device-free die. The first die includes a first device. The second die includes a second device and is bonded to the first die. The device-free die is located aside the second die and is bonded to the first die. The device-free die includes a conductive feature electrically connected to the first die and the second die.

Three-dimensional integrated circuit structures are disclosed. A three-dimensional integrated circuit structure includes a first die, a second die and a device-free die. The first die includes a first device. The second die includes a second device and is bonded to the first die. The device-free die is located aside the second die and is bonded to the first die. The device-free die includes a conductive feature electrically connected to the first die and the second die.

In an embodiment, a method includes: stacking a plurality of first dies to form a device stack; revealing testing pads of a topmost die of the device stack; testing the device stack using the testing pads of the topmost die; and after testing the device stack, forming bonding pads in the topmost die, the bonding pads being different from the testing pads.

In an embodiment, a method includes: stacking a plurality of first dies to form a device stack; revealing testing pads of a topmost die of the device stack; testing the device stack using the testing pads of the topmost die; and after testing the device stack, forming bonding pads in the topmost die, the bonding pads being different from the testing pads.

A method includes forming a first device die, which includes depositing a first dielectric layer, and forming a first metal pad in the first dielectric layer. The first metal pad includes a recess. The method further includes forming a second device die including a second dielectric layer and a second metal pad in the second dielectric layer. The first device die is bonded to the second device die, with the first dielectric layer being bonded to the second dielectric layer, and the first metal pad being bonded to the second metal pad.

A method includes forming a first device die, which includes depositing a first dielectric layer, and forming a first metal pad in the first dielectric layer. The first metal pad includes a recess. The method further includes forming a second device die including a second dielectric layer and a second metal pad in the second dielectric layer. The first device die is bonded to the second device die, with the first dielectric layer being bonded to the second dielectric layer, and the first metal pad being bonded to the second metal pad.