Patent ID: 11961813
Assignee: QORVO US, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method comprising:
providing a precursor wafer comprising a plurality of device regions, a plurality of individual interfacial layers, and a silicon handle substrate wherein:
each of the plurality of device regions includes a back-end-of-line (BEOL) portion and a front-end-of-line (FEOL) portion over the BEOL portion, wherein the FEOL portion comprises isolation sections and an active layer, which is surrounded by the isolation sections and does not extend vertically beyond the isolation sections;
each of the plurality of individual interfacial layers is directly over one active layer of a corresponding device region, wherein each of the plurality of individual interfacial layers is formed of silicon germanium (SiGe) with a uniform concentration of germanium greater than 15%;
the silicon handle substrate is over each of the plurality of individual interfacial layers, wherein each of the plurality of individual interfacial layers is not strained by the silicon handle substrate, and has a lattice constant greater than 5.461 at a temperature of 300K; and
each active layer is formed from an individual strained silicon epitaxial layer, which is grown over a corresponding individual interfacial layer, wherein the lattice constant of silicon in the individual strained silicon epitaxial layer is greater than 5.461 at a temperature of 300K;

removing the silicon handle substrate completely; and
applying a first mold compound to provide a mold device wafer that includes a plurality of mold device dies; wherein:
the first mold compound is applied over the active layer of each of the plurality of device regions from where the silicon handle substrate is removed;
silicon crystal, which has no germanium, nitrogen, or oxygen content, does not exist between the active layer of each of the plurality of device regions and the first mold compound; and
each of the plurality of mold device dies includes a corresponding device region and a portion of the first mold compound over the active layer of the corresponding device region.