3D Semiconductor Wafer Buffer Layer for Safer Carrier Switches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The large topography variation on the upper surface of interposer structures in chip-on-wafer-on-substrate packages poses challenges during carrier-switch processes, leading to potential damage of sub-underbump metallurgies due to the need for thick adhesives, which are difficult to remove without damaging the underlying layers.
Innovation Solution
A buffer layer is deposited over the conductive features to smooth the topography, allowing for the use of thinner adhesives during carrier-switch processes, reducing the risk of damage to the dielectric layers and ensuring easier removal of the adhesive without compromising the structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If thick adhesive is used to attach carrier during carrier-switch process, then the adhesive can cover the large topography variation, but the adhesive becomes difficult to remove without damaging the underlying sub-underbump metallurgies
Solution Approach 1:
A buffer layer is deposited over the sub-underbump metallurgies before the carrier-switch process. This preliminary action creates a protective barrier that enables the use of thinner adhesive while preventing damage to the metallurgies during adhesive removal, thus resolving the contradiction between covering topography variation and ease of adhesive removal
Solution Approach 2:
The buffer layer acts as an intermediary between the adhesive and the sub-underbump metallurgies. It allows the adhesive to be applied and removed without directly contacting and damaging the metallurgies, thus enabling easier adhesive removal while maintaining protection of the underlying structures
2Ease of manufacture
If thinner adhesive is used during carrier-switch process, then the adhesive can be easily removed, but it cannot adequately cover the large topography variation on the interposer surface
Solution Approach 1:
The buffer layer is deposited in advance to fill and smooth the topography variations on the interposer surface. This preliminary smoothing action allows thinner adhesive to be used while still achieving adequate coverage, thus resolving the contradiction between adhesive removal ease and topography coverage
Solution Approach 2:
The buffer layer changes the surface topology parameters by reducing the height differences and topography variation. This parameter change enables the use of thinner adhesive that can still cover the surface adequately, thus resolving the contradiction between thin adhesive usage and topography coverage
Data Source
AI summary
Embodiments provide a method of performing a carrier switch for a device wafer, attaching a second wafer and removing a first wafer. A buffer layer is deposited over the device wafer, buffer layer reducing the topography of the surface of the device wafer. After the carrier switch a film-on-wire layer is removed from the buffer layer and then the buffer layer is at least in part removed.