Wafer-Level Package Domes for Dense Interconnect Layout
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Solution Overview
Problem
Current wafer level packages require excessive space due to safety distances needed for process variations, leading to inefficient use of chip area and limiting the availability of active filter and interconnect areas.
Innovation Solution
A wafer level package design that minimizes space usage by using a first dielectric package layer with domes over cavities and a second reinforcing polymer layer, allowing for individual placement of interconnect structures without full coverage, and optionally a third resist layer for structural edges, enabling efficient use of substrate surface and improved mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple safety distances are maintained for process variations, then manufacturing reliability is improved, but available substrate area for active structures is reduced
Solution Approach 1:
The patent transitions from planar 2D packaging to 3D vertical packaging by forming domes with cavities that extend upward from the substrate. This dimensional change allows safety distances to be maintained in the vertical dimension rather than consuming horizontal substrate area, resolving the contradiction between reliability and available area.
Solution Approach 2:
The patent nests multiple functional elements within the dome structures: device structures are placed inside cavities, which are enclosed by domes formed from the first package layer. This nesting allows compact arrangement of components while maintaining necessary separation distances for manufacturing reliability.
2Strength
If full coverage with package layers is applied, then mechanical protection is improved, but substrate area availability is reduced
Solution Approach 1:
The patent applies package layers selectively rather than uniformly across the entire substrate. The first package layer forms domes only over specific cavity regions, and the second package layer is applied only where reinforcement is needed. This localized approach provides mechanical protection where required while preserving substrate area for active structures.
Solution Approach 2:
The second package layer is applied partially rather than in full coverage. It is deposited only in regions where additional mechanical reinforcement is needed, such as over the domes or in specific structural areas, rather than covering the entire substrate surface. This partial action maintains necessary protection while maximizing available area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design reduces the need for safety distances, allowing closer placement of interconnects to sensitive structures, enhances thermal management, improves electrical performance, and maintains mechanical stability while optimizing substrate area usage.
Implementation Method 1
After depositing a rigid cover layer (first package layer) the structures of the sacrificial material may be etched or dissolved through release holes of the first package layer. The first package layer forms a dome over each cavity.
Implementation Method 2
The second package layer may be a layer of a photosensitive polymer e.g. a photosensitive resist. Then, structuring of the second package layer can be performed by simply exposing the resist to a scanning light source or by exposing it to a light source with the help of a photo mask. After exposure the polymer layer is developed to remove undesired surface portions
Data Source
AI summary
A fullcover package solution in comnination with copper pillars or solder bumps and acoustic cavities is propsed to provide maximum usable design area compared to current thin film acoustic wafer level packages. Manufacturing can be done in a self-aligned interconnection process.