3D PLUS has patented an innovative 3D technology based on the stacking of Know Good Rebuilt Wafers with only Know Good Dies, named WDoDTM.

The first 2D steps are those used by the manufacturers of Rebuilt Wafers with well-known eWLBTM technology:

  • - Pick-Flip and Place of KGD from the die wafer on an thermal-release tape on a silicon carrier ( 300 or 200 mm diameter)

  • - Compression molding with epoxy resin with silica fillers

  • - Know Good Rebuilt Wafer grinding in order to decrease total thickness to 250 Âμm or less

  • - Fan-out built-up with Redistribution layer process

  • - This last step can be replaced by interconnection of the die to external sides by “flat” gold wires, in specific conditions

The next steps concern the WDoDTM process with edge connection.

  • - gluing of first Know Good Rebuilt Wafer

  • - sequential staking and gluing of Know Good Rebuilt Wafers

  • - dicing of rebuilt and stacked wafers

  • - plating of dicing streets with electroless process

All these steps can be collective at the wafer level.

Final laser patterning on the plated edges of each module is the final step before electrical test.

3D PLUS has designed with LINANOVA and manufactured two different electronic modules in the frame of a feasibility study of implantable products.

These developments were funded by one European project named MANPOWER for a first application dedicated for leadless pacemaker and by a French PIA project (INTENSE) dedicated to neurostimulation for severe conditions, particularly refractory heart failure.

Description of these modules is detailed: these modules have several layers including PCB layers including components which cannot be processed with fan out technology.

Layers only with bare dies are processed with fan out WLP technology eWLB based or with “falt” gold wires. Top and bottom sides of these modules can be also populated by additional components and allow the interconnexion with other sub-modules. They can also be solderballed in order to be reflow as a BGA components.

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