mmWave Package Transition Matching Using Segmented Ground Planes
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Solution Overview
Problem
Current electronic packaging solutions for millimeter wave semiconductor dies face challenges such as high electrical losses and size increases due to the use of SMT packages at high frequencies, and waveguide interfaces require complex assembly processes and expensive materials, limiting their applicability above 50 GHz.
Innovation Solution
A novel electronic packaging system using standard PCB technology with a simple metal lid, incorporating a single layer of organic dielectric laminate for low-loss high-frequency signal transmission, and employing conventional reflow soldering for assembly, along with hybrid attachment methods like wire bonds and solder bumps, to enable efficient heat dissipation and compact, cost-effective packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If SMT packages with printed transmission lines are used for mmWave frequencies, then ease of manufacture and small dimensions are achieved, but electrical losses increase significantly
Solution Approach 1:
The package is segmented into distinct functional zones: a waveguide interface section for high-frequency signal transmission with minimized loss, and an SMT section for ease of manufacture and integration. The transition between these segments is carefully designed to maintain signal integrity while enabling mass production through standard SMT processes.
Solution Approach 2:
Different regions of the package are assigned different structural qualities optimized for their specific functions. The waveguide interface region uses precision-machined metal structures for low-loss mmWave transmission, while the SMT region uses standard printed transmission lines optimized for manufacturing ease. This local differentiation allows each region to excel at its intended function without compromising the other.
2Loss of energy
If waveguide interfaces are used for high-frequency signals, then electrical losses are reduced, but package size increases and assembly complexity increases
Solution Approach 1:
The patent merges the waveguide interface and SMT package into a single integrated structure. The waveguide section is directly coupled to the SMT substrate, eliminating the need for separate assembly steps and mechanical connectors. This integration maintains the low-loss benefits of waveguides while achieving the compact size and manufacturing simplicity of SMT packages.
Solution Approach 2:
The package design achieves multi-functionality by incorporating both waveguide interface capabilities and SMT mounting capabilities within a single structure. This universal design allows the package to handle mmWave signals with minimal loss while also being compatible with standard automated assembly processes and achieving compact dimensions suitable for high-density circuit boards.
3Loss of energy
If waveguide interfaces are used for mmWave transmission, then signal loss is minimized, but manufacturing cost increases due to expensive materials and manual assembly
Solution Approach 1:
The patent changes the manufacturing parameters and material specifications to achieve cost-effectiveness. Instead of using expensive precision-machined waveguide components throughout, the design uses standard SMT-compatible substrates and materials, with the waveguide section implemented as a simplified structure that can be manufactured using conventional processes. This parameter optimization maintains acceptable signal loss performance while dramatically reducing manufacturing costs.
Data Source
AI summary
A mmWave electronics package constructed from common Printed Circuit Board (PCB) technology and a metal cover. Assembly of the package uses standard pick and place technology and heat is dissipated directly to a pad on the package. Input/output of mmWave signal(s) is achieved through a rectangular waveguide. Mounting of the electronic package to an electrical printed circuit board (PCB) is performed using conventional reflow soldering processes and includes a waveguide I/O connected to an mmWave antenna. The electronic package provides for transmission of low frequency, dc and ground signals from the semiconductor chip inside the package to the PCB it is mounted on. An impedance matching scheme matches the chip to high frequency board transition by altering the ground plane within the chip. A ground plane on the high frequency board encircles the high frequency signal bump to confine the electromagnetic fields to the bump region reducing radiation loss.