Industry's First Wafer-level Heterogeneous Integration of GaAs on Silicon for RF FEM Manufacturing

EV Group (EVG), a supplier of wafer bonding and lithography equipment, has partnered with Ningbo Semiconductor International Corporation (NSI), a specialty semiconductor foundry based in Ningbo, China, for the development of industry's first process technology platform for wafer-level heterogeneous integration of gallium arsenide (GaAs) on silicon for use in RF front-end module (FEM) manufacturing. This marks an important milestone in the development of next-generation, high-performance, ultra-compact RF front-end chipsets that are needed for 4G and 5G smartphones and other handsets.

As part of this strategic collaborative effort, EVG provided NSI with its leading temporary bonding/debonding (TB/DB), permanent bonding, mask alignment lithography, and related special metrology equipment and process expertise, which NSI leveraged together with its proprietary Micro Wafer-Level System Integration (uWLSI) technology platform to produce the innovative RF FEM products for a leading RF front-end devices and system solution provider. NSI is a joint venture subsidiary of Semiconductor Manufacturing International Corporation (SMIC) with China IC Investment Fund, Ningbo Economic Development Zone Industrial Investment Company, Ltd. and other IC investment funds.

High-performance, ultra-compact RF front-end microsystem components are vital to the success of the 5G wireless terminal. To support the customers and their RF front-end module products of the next generation wireless terminals to meet the stringent requirements of lower insertion loss, higher energy efficiency, ultra-miniaturization, etc., it is necessary to provide more advanced wafer-level multi-chip heterogeneous integration process solutions for supporting and helping the customers meet the product standards and quickly ramp to volume production.

RF FEMs include several key components, such as power amplifiers (PAs), antenna switches and filters. The high-density 3D heterogeneous integration of materials with different properties, such as GaAs and silicon, is effective in enabling improved gain, linearity and power performance for RF FEMs. At the same time, however, the migration to 5G broadband wireless technology is driving the need for wider multi-band PAs and more RF filters in the FEM, which in turn can drive up cost and footprint of the overall chipset package. Enabling heterogeneous system integration at the wafer level provides a cost-effective approach for achieving greater chipset density with minimal footprint increase.

uWLSI (Micro Wafer-Level System Integration) is a middle-end-of-line technology platform for a unique wafer fabrication process developed by NSI for enabling heterogeneous multi-die-on-wafer system integration and wafer-level system testing while eliminating the need for bumping and flip-chip processes in typical system-in-package practices. NSI developed the uWLSI technology platform to specifically address the surging need for high-density heterogeneous system integration of a variety of chipsets and microsystems through more wafer-level fabrication processing.

EVG's TB/DB systems play a key role in enabling the heterogeneous integration of compound semiconductors with silicon devices in a More-than-Moore approach. For example, TB/DB facilitates the reliable transfer and processing of very thin compound semiconductor, silicon and mold wafers, which can be integrated into higher-density vertical packages. Likewise, EVG's mask alignment systems support wafer-level heterogeneous integration by enabling lithography patterning of carrier-mounted and warped substrates, which is essential for the uWLSI process.

EVG showcased its latest wafer bonding and lithography solutions for heterogeneous integration and other applications at SEMICON China.