RF Die Embedding in Package Substrate for Compact Wireless Assemblies
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Solution Overview
Problem
The integration of high-performance wireless radios, such as millimeter wave radios, into small-sized integrated circuit (IC) packages is challenging due to size constraints, thermal issues, and power delivery limitations, which affects wireless communication devices like smartphones and tablets.
Innovation Solution
The solution involves embedding an RF die within the IC package substrate with the RF front end positioned underneath the RF die, ensuring the RF front end does not extend beyond the die's lateral surface area, thereby reducing the package size and minimizing signal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the RF die and front end are arranged side-by-side on the package substrate, then the wireless communication functionality is achieved, but the package size increases
Solution Approach 1:
The RF front end is positioned underneath the RF die, nesting one component within the footprint of another. This vertical integration allows the front end to be contained within the lateral boundaries of the RF die, effectively utilizing three-dimensional space rather than requiring additional lateral area, thus reducing overall package size while maintaining both wireless communication functions
Solution Approach 2:
The patent transitions from a two-dimensional side-by-side arrangement to a three-dimensional stacked configuration. By positioning the RF front end in the vertical dimension underneath the RF die, the design exploits the Z-axis to accommodate both components without increasing the X-Y footprint, thereby reducing package area while preserving functionality
2Area of stationary object
If the package size is reduced to fit compact devices, then device compactness is improved, but signal noise increases
Solution Approach 1:
By nesting the RF front end underneath the RF die within its lateral footprint, the design minimizes the distance between related components while containing them within a compact footprint. This reduces the overall package size without significantly increasing signal noise, as the critical RF signals remain localized and shielded by the embedded configuration
Solution Approach 2:
The patent applies different spatial arrangements to different components: the RF die is positioned at the top for optimal signal radiation, while the front end is embedded underneath for compact integration. This localized optimization allows compact packaging while maintaining signal quality by preserving the RF die's exposure and minimizing interference through strategic component placement
3Reliability
If the RF front end extends beyond the die's lateral surface area, then signal transmission is improved, but package size increases
Solution Approach 1:
The RF front end is nested within the lateral footprint of the RF die, with its projection onto the package substrate completely contained within the die's boundaries. This embedding allows the front end to be electrically connected to the die while maintaining compact packaging, as the interconnects route signals vertically through the substrate rather than requiring lateral extension
Solution Approach 2:
The patent resolves the signal transmission requirement by utilizing vertical interconnects through the substrate rather than lateral extensions. The RF front end communicates with the die through conductive pathways in the Z-dimension (via holes, trenches, or stacked vias), allowing compact lateral packaging while maintaining reliable signal transmission through the vertical dimension
Data Source
AI summary
Microelectronic assemblies, and related devices and methods, are disclosed herein. For example, in some embodiments, a microelectronic assembly may include a package substrate having a first surface and an opposing second surface; a radio frequency (RF) die having a lateral surface area and a plurality of contacts on a face, where the RF die is embedded in the package substrate with the plurality of contacts facing towards the second surface of the package substrate, and an RF front end between the RF die and the first surface of the package substrate, where the RF front end is positioned under the RF die and does not extend beyond the lateral surface area of the RF die.