RF MMIC Packaging

CIL provides RF MMIC GaN and GaAS packaging solutions, ranging from discrete transistors, packaged MMIC solutions in a multitude of different markets in frequencies shown below

• Plastic overmolded QFN's    up to 30GHz
• Plastic Open cavity QFN's     up to 70GHz and possibly up to 120GHz
• Ceramic Open cavity QFN's  up to 70GHz and possibly up to 120GHz 

Key Packaging Technologies & Types

• QFN/LGA (Quad-Flat No-leads / Land Grid Array): Common for cost-effective, high-volume, surface-mount (SMT) applications up to ~30 GHz, offering good RF/thermal performance with small footprints.
• Ceramic/Air-Cavity Packages: Used for high-reliability, high-power, and high-frequency MMICs (up to 100 GHz), often utilizing Kovar or specialized ceramics with brazed metal heat spreaders.
• Flip-Chip (WLCSP): Enables high-frequency (100+ GHz) performance by reducing parasitic inductance and avoiding wire bonds.
• Multi-Chip Modules (MCM) & AiP: Integration of multiple die or Antenna-in-Package (AiP) technology to create compact, system-level solutions. 

Key Considerations for MMIC Packaging

• High Frequency Performance: Minimizing parasitic inductance (wire bonds) and capacitance is crucial, with <0.2 nH required for 45+ GHz operation.
• Thermal Management: High-power MMICs (GaN, GaAs) require direct, thermally conductive paths, often using copper-tungsten, specialized ceramic heat sinks and increasingly silver sinter die attach.
• Interconnects: Flip-chip bonding is preferred for high-frequency, while gold wire bonding is common for reliability in ceramic packages.
• Materials: Fused quartz substrates offer excellent RF performance for specialized applications. 

Common Applications
RF MMIC packages are critical for 5G, automotive radar, satellite communications, and aerospace applications, typically operating from X-band up to 100 GHz

In early 2021, CIL became the semiconductor assembly partner for a Department for Science, Innovation and Technology (DSIT) project OranGaN. This project brought together lead partner INEX Microtechnology, CIL with Viper RF and Compound Semiconductor Applications (CSA) Catapult. The project developed new manufacturing processes and packaging solutions to create 5G components such as Monolithic Microwave Integrated Circuit Chips (MMIC). Currently, there are no commercial RF-GaN devices fully developed and manufactured in the UK that can be used in 5G applications. MMIC chips are used in power amplifiers— components that boost signals before they are transmitted from a base station to smartphones and computers. CIL's participation in the project was to develop QFN style packaging including die attach, wire bonding, plastic overmold, device separation and marking for devices operating at up to 40GHz. As part of the project CIL installed a Boschman UNISTAR Auto Plastic overmold machine capable of medium and volume production of QFN style devices.

 With the opening of CIL's BP2 semiconductor packaging facility in June 2023, the largest facility in the UK, all of the processes came together in one cleanroom. They include

• Custom Lead-frame design to match die design
• Wafer dicing using DISCO DAD3361 dicing system and associated water purification system
• Die bonding using conductive / non-conductive epoxies 
• Die bonding using eutectic soldering via formic acid soldering systems
• Die bonding using Silver Sintering techniques for GaN based power devices
• Gold Au wedge & Gold Au Ball bonding utilizing advanced automated equipment for high frequency (40GHz) operation
• QFN style Plastic overmold using Boschman UNISTAR overmold machine.
• Device separation using dicing system
• Laser marking identification system
• Die sizes from 0.2mm x 0.2mm upwards
• Wirebond counts from 1 / device up to 100’s / device
• Fitting of multiple single layer capacitors within the same package
• And many combinations thereof…

When you consider that CIL compliments this with Automatic Wire Bonding and our extensive SMT & test capabilities, CIL can offer a total product solution.

Get in touch with our Business Development team, and arrange a visit to meet the CIL Advanced Technology Group in order to explore applications and manufacturing methods available.