The present disclosure provides devices and methods in which a semiconductor chip has a reduced size and thickness. The device is manufactured by utilizing a sacrificial or dummy silicon wafer. A recess is formed in the dummy silicon wafer where the semiconductor chip is mounted in the recess. The space between the dummy silicon wafer and the chip is filled with underfill material. The dummy silicon wafer and the backside of the chip are etched using any suitable etching process until the dummy silicon wafer is removed, and the thickness of the chip is reduced. With this process, the overall thickness of the semiconductor chip can be thinned down to less than 50 m in some embodiments. The ultra-thin semiconductor chip can be incorporated in manufacturing flexible/rollable display panels, foldable mobile devices, wearable displays, or any other electrical or electronic devices.

A semiconductor package includes a lower semiconductor chip disposed on a substrate, at least one upper semiconductor chip disposed on the lower semiconductor chip, a heat spreader bonded on the lower semiconductor chip and the at least one upper semiconductor chip, and an encapsulant surrounding side surfaces of the heat spreader. A lower surface of the heat spreader includes a first protrusion and a non-protruding portion, the first protrusion is in contact with an upper surface of the lower semiconductor chip, and the non-protruding portion is in contact with an upper surface of the at least one upper semiconductor chip.

A semiconductor package includes a lower semiconductor chip disposed on a substrate, at least one upper semiconductor chip disposed on the lower semiconductor chip, a heat spreader bonded on the lower semiconductor chip and the at least one upper semiconductor chip, and an encapsulant surrounding side surfaces of the heat spreader. A lower surface of the heat spreader includes a first protrusion and a non-protruding portion, the first protrusion is in contact with an upper surface of the lower semiconductor chip, and the non-protruding portion is in contact with an upper surface of the at least one upper semiconductor chip.

Embodiments of three-dimensional (3D) memory devices with stacked device chips using interposers and fabrication methods thereof are disclosed. In an example, a method for forming a 3D memory device is disclosed. An alternating conductor/dielectric stack is formed at a first side of a chip substrate. A memory string extending vertically through the alternating conductor/dielectric stack is formed. A chip contact is formed at a second side opposite to the first side of the chip substrate and is electrically connected to the memory string. A first interposer contact is formed at a first side of an interposer substrate. A second interposer contact is formed at a second side opposite to the first side of the interposer substrate and is electrically connected to the first interposer contact through the interposer substrate. The first interposer contact is attached to the chip contact.

Embodiments of three-dimensional (3D) memory devices with stacked device chips using interposers and fabrication methods thereof are disclosed. In an example, a method for forming a 3D memory device is disclosed. An alternating conductor/dielectric stack is formed at a first side of a chip substrate. A memory string extending vertically through the alternating conductor/dielectric stack is formed. A chip contact is formed at a second side opposite to the first side of the chip substrate and is electrically connected to the memory string. A first interposer contact is formed at a first side of an interposer substrate. A second interposer contact is formed at a second side opposite to the first side of the interposer substrate and is electrically connected to the first interposer contact through the interposer substrate. The first interposer contact is attached to the chip contact.

A display device includes a flexible base layer including a first portion and a second portion disposed around the second portion; a display unit disposed on a first surface of the first portion and including a light emitting element; a driving circuit disposed on a first surface of the second portion and including a driving chip; a support member attached to a second surface of the first portion and a second surface of the second portion; and an adhesive member disposed between the flexible base layer and the support member, wherein the adhesive member includes a first adhesive member having a first elastic modulus and a second adhesive member having a second elastic modulus that is higher than the first elastic modulus, and the second adhesive member overlaps the driving circuit.

A display device includes a flexible base layer including a first portion and a second portion disposed around the second portion; a display unit disposed on a first surface of the first portion and including a light emitting element; a driving circuit disposed on a first surface of the second portion and including a driving chip; a support member attached to a second surface of the first portion and a second surface of the second portion; and an adhesive member disposed between the flexible base layer and the support member, wherein the adhesive member includes a first adhesive member having a first elastic modulus and a second adhesive member having a second elastic modulus that is higher than the first elastic modulus, and the second adhesive member overlaps the driving circuit.

An electronic device is provided in the present disclosure. The electronic device includes a substrate and a light emitting diode. The light emitting diode is bonded to the substrate through a solder alloy. The solder alloy includes tin and a metal element M, and the metal element M is one of the indium and bismuth. The atomic percentage of tin in the sum of tin and the metal element M ranges from 60% to 90% in the solder alloy.

An electronic device is provided in the present disclosure. The electronic device includes a substrate and a light emitting diode. The light emitting diode is bonded to the substrate through a solder alloy. The solder alloy includes tin and a metal element M, and the metal element M is one of the indium and bismuth. The atomic percentage of tin in the sum of tin and the metal element M ranges from 60% to 90% in the solder alloy.

Embodiments of three-dimensional (3D) memory devices with stacked device chips using interposers and fabrication methods thereof are disclosed. In an example, a 3D memory device includes first and second device chips and an interposer therebetween. The first device chip includes a peripheral device and a first chip contact on a surface of the first device chip and electrically connected to the peripheral device. The second device chip includes an alternating conductor/dielectric stack, a memory string extending vertically through the alternating conductor/dielectric stack, and a second chip contact on a surface of the second device chip and electrically connected to the memory string. The interposer includes an interposer substrate, first and second interposer contacts on opposite surfaces of the interposer and electrically connected to one another through the interposer substrate. The first and second interposer contacts are attached to the first and second chip contacts, respectively.