Embedded actives and discrete passives in a cavity within build-up layers
Disclosed are any electronic system or module which includes embedded actives and discrete passives, and methods for use in fabricating packages containing embedded active devices and/or discrete passive devices. Exemplary apparatus comprises a plurality of build-up layers defining circuit interconnections and that comprise one or more thin film type of embedded passive devices, at least a cavity formed in the build-up layers, and at least an active device and/or at least a discrete passive device disposed in the cavity and electrically connected to the circuit interconnections of the build-up layers. A stiffener may be coupled to an exposed (back) surface of the active device and to an adjacent surface of the build-up layers. The build-up layers may be mounted to a core, and the core may be attached to a printed circuit board. Alternatively, a bottom surface of the build-up layers may be mounted to a printed circuit board without core. The packages have a chip reworkability, an easier thermal management, a very thin profile and enhanced electrical performance comparable to packages produced using chip-first or chip-middle approaches.
1. A method comprising:
fabricating an embedded active package including a top surface and a bottom surface comprising a plurality of build-up layers defining circuit interconnections and that comprise one or more thin film embedded passive devices;
after fabricating the plurality of build-up layers, forming at least one cavity in the build-up layers; and
after forming the at least one cavity, disposing at least one active device in the cavity that is electrically connected to the circuit interconnections of the build-up layers, wherein the electrical connections of the cavity to the circuit interconnections of the build-up layers include a plurality of nano-interconnects or a plurality of bumpless interconnects, and
wherein at least one electrical connection is provided to one or more of the plurality of build-up layers on the top surface of the embedded active package and at least one electrical connection is provided to one or more of the plurality of build-up layers on the bottom surface of the embedded active package.
2. The method recited in claim 1 further comprising forming the build-up layers on a core.
3. The method recited in claim 2 further comprising mounting a bottom surface of the core to a printed circuit board, module substrate or another apparatus.
4. The method recited in claim 2 wherein the core is selected from a group including ceramics, metals, organics and combinations thereof.
5. The method recited in claim 1 further comprising mounting a bottom surface of the build-up layers without core directly to a printed circuit board, module substrate or another apparatus.
6. The method recited in claim 1 further comprising attaching a stiffener to an exposed surface of the at least one active device and an exposed surface of the build-up layers.
7. The method recited in claim 6 wherein the stiffener comprises a high thermal conductivity and electrically conductive metal layer that provides for thermal management and EMI shielding.
8. The method recited in claim 1 further comprising securing the active device in the cavity using underfill and engineered adhesive material.
9. The method recited in claim 1 further comprising connecting the active device to the build-up layers using low profile interconnects, solder bumps, metal columns or bumpless interconnections.