2.5D TSV MEOL flows

CoC/CoW CHIP-LAST

Interposer (TSV/BEOL/front side pads) from fab -> Front-side carrier bond (to handle thin interposers) -> TSV reveal / Si etch, TSV remove (CVD/CMP), backside RDL + C4 -> Flip & rebond carrier on backside -> CoW top die attach -> Carrier debond & dicing -> Module attach to substrate

This is good for large die & thin core substrates.

CoS

Interposer (TSV/BEOL/front side pads) from fab -> Front-side carrier bond (to handle thin interposers) -> TSV reveal / Si etch, TSV remove (CVD/CMP), backside RDL + C4 -> Carrier debond & dicing -> Interposer to substrate attach -> Top die attach to module

Leverage FCBGA process, low cost.

TSV-free approach / SLIM (Amkor) (CoS)

TSV-free Interposer (NO TSV/BEOL/front side pads) from fab -> Front-side carrier bond (to handle thin interposers) -> Si etch , backside RDL + C4 -> Carrier debond & dicing -> Interposer to substrate attach -> Top die attach to module

2.1D / Package Organic Interposer

Typical layer count could be 3+1+2+2: 3 layers with 2/2 L&S, 1 BU (above core) + 2 Core + 2 BU (below core)