A method of forming a redistribution structure includes providing a dielectric layer. The dielectric layer is patterned to form a plurality of via openings. A seed layer is formed on the dielectric layer and filling in the plurality of via openings. A patterned conductive layer is formed a on the seed layer, wherein a portion of the seed layer is exposed by the patterned conductive layer. The portion of the seed layer is removed by using an etching solution, thereby forming a plurality of conductive lines and a plurality of vias. During the removing the portion of the seed layer, an etch rate of the patterned conductive layer is less than an etch rate of the seed layer.

A method of forming a redistribution structure includes providing a dielectric layer. The dielectric layer is patterned to form a plurality of via openings. A seed layer is formed on the dielectric layer and filling in the plurality of via openings. A patterned conductive layer is formed a on the seed layer, wherein a portion of the seed layer is exposed by the patterned conductive layer. The portion of the seed layer is removed by using an etching solution, thereby forming a plurality of conductive lines and a plurality of vias. During the removing the portion of the seed layer, an etch rate of the patterned conductive layer is less than an etch rate of the seed layer.

A package structure including a bottom die, a first die, a second die, an encapsulant and a first dummy structure is provided. The first die and a second die are bonded to a first side of the bottom die. The encapsulant laterally encapsulates the first die and the second die. The first dummy structure is bonded to the first side of the bottom die, wherein a sidewall of the first dummy structure is coplanar with a first sidewall of the bottom die.

A package structure including a bottom die, a first die, a second die, an encapsulant and a first dummy structure is provided. The first die and a second die are bonded to a first side of the bottom die. The encapsulant laterally encapsulates the first die and the second die. The first dummy structure is bonded to the first side of the bottom die, wherein a sidewall of the first dummy structure is coplanar with a first sidewall of the bottom die.

A method includes bonding a first and a second device die to a third device die, forming a plurality of gap-filling layers extending between the first and the second device dies, and performing a first etching process to etch a first dielectric layer in the plurality of gap-filling layers to form an opening. A first etch stop layer in the plurality of gap-filling layers is used to stop the first etching process. The opening is then extended through the first etch stop layer. A second etching process is performed to extend the opening through a second dielectric layer underlying the first etch stop layer. The second etching process stops on a second etch stop layer in the plurality of gap-filling layers. The method further includes extending the opening through the second etch stop layer, and filling the opening with a conductive material to form a through-via.

A method includes bonding a first and a second device die to a third device die, forming a plurality of gap-filling layers extending between the first and the second device dies, and performing a first etching process to etch a first dielectric layer in the plurality of gap-filling layers to form an opening. A first etch stop layer in the plurality of gap-filling layers is used to stop the first etching process. The opening is then extended through the first etch stop layer. A second etching process is performed to extend the opening through a second dielectric layer underlying the first etch stop layer. The second etching process stops on a second etch stop layer in the plurality of gap-filling layers. The method further includes extending the opening through the second etch stop layer, and filling the opening with a conductive material to form a through-via.

A semiconductor package includes a first semiconductor chip, which includes a first semiconductor substrate and a first bonding layer on the first semiconductor substrate. A second semiconductor chip includes a second semiconductor substrate, a second bonding layer bonded to the first bonding layer, and a chip-through-via which penetrates the second semiconductor substrate and is connected to the second bonding layer. A passivation film extends along an upper side of the second semiconductor chip and does not extend along side-faces of the second semiconductor chip. The chip-through-via penetrates the passivation film. A multiple-gap-fill film extends along the upper side of the first semiconductor chip, the side faces of the second semiconductor chip, and the side faces of the passivation film. The multiple-gap-fill films includes an inorganic filling film and an organic filling film which are sequentially stacked on the first semiconductor chip.

Provided is packages and methods of fabricating a package and. The method includes bonding a first device die with a second device die. The second device die is over the first device die. A bonding structure is formed in a combined structure including the first and the second device dies. A component is formed in the bonding structure. The component includes a passive device or a transmission line. The method further includes forming a first and a second electrical connectors electrically coupling to a first end and a second end of the component.

Provided is packages and methods of fabricating a package and. The method includes bonding a first device die with a second device die. The second device die is over the first device die. A bonding structure is formed in a combined structure including the first and the second device dies. A component is formed in the bonding structure. The component includes a passive device or a transmission line. The method further includes forming a first and a second electrical connectors electrically coupling to a first end and a second end of the component.

A package structure including a photonic, an electronic die, an encapsulant and a waveguide is provided. The photonic die includes an optical coupler. The electronic die is electrically coupled to the photonic die. The encapsulant laterally encapsulates the photonic die and the electronic die. The waveguide is disposed over the encapsulant and includes an upper surface facing away from the encapsulant. The waveguide includes a first end portion and a second end portion, the first end portion is optically coupled to the optical coupler, and the second end portion has a groove on the upper surface.