Vertical e-Bar Structure for Grinding-Resistant Inverted eWLB Packaging
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Solution Overview
Problem
Excessive grinding during the planarization process can reduce the thickness of vertical interconnect structures in semiconductor devices, leading to defects and reduced manufacturing yield.
Innovation Solution
Incorporating a thicker conductive layer in the vertical interconnect structure to withstand grinding while maintaining electrical connectivity, ensuring the contact points for interconnects are not compromised.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard thickness conductive layer is used during grinding operation, then the manufacturing process is simpler and cost-effective, but the contact surface is removed leading to defects and reduced yield
Solution Approach 1:
The conductive layer is formed with excessive thickness (40.0 μm or greater) before the grinding operation, providing a buffer that prevents complete removal of the contact surface during grinding. This preliminary over-provisioning ensures that even with material removal, sufficient conductive material remains to maintain electrical connectivity and prevent defects.
Solution Approach 2:
The thickness parameter of the conductive layer is changed from standard thickness to significantly increased thickness (40.0 μm or greater). This parameter change transforms the conductive layer into a robust structure that can withstand the grinding process while maintaining the contact surface, thereby improving manufacturing yield without requiring complex process modifications.
2Manufacturing precision
If excessive grinding is performed to planarize the surface, then the surface flatness is improved, but the thickness of vertical interconnect structure is reduced leading to contact surface removal
Solution Approach 1:
The conductive layer is designed with excessive thickness (40.0 μm or greater) to provide a cushion or buffer against the harmful effect of excessive grinding. This cushioning effect ensures that even if grinding removes more material than intended, the contact surface remains protected and electrical connectivity is maintained, preventing defects.
Solution Approach 2:
The conductive layer thickness is made asymmetrically different from standard dimensions, being significantly thicker (40.0 μm or greater) than conventional designs. This asymmetric thickness distribution creates a robust structure where the bulk of the conductive material is positioned to protect the contact surface during grinding, allowing aggressive planarization without contact surface removal.
Data Source
AI summary
A semiconductor device has an electrical component and an e-bar structure disposed to a side of the electrical component. An encapsulant is deposited over the electrical component and e-bar structure. An RDL is formed over the electrical component, encapsulant, and e-bar structure. The e-bar structure has a core layer, a first conductive layer formed over a first surface of the core layer, and a second conductive layer formed over a second surface of the core layer. The second conductive layer includes a thickness greater than the first conductive layer. The RDL has an insulating layer formed over the electrical component and encapsulant, and a conductive layer formed over the insulating layer. A bump is formed over a contact pad of the e-bar structure opposite the RDL. A contact pad of the electrical component is electrically connected to the RDL opposite the bump.