By Dr. Phil Garrou, Contributing Editor

Finishing up our look at the Semi 3D Summit in Grenoble we’ll look at the presentations of Besi, IMEC, AMS, Asahi Glass and Yole.

BESI – 3D Stacking with Thermocompression Bonding (TCB)

Hugo Pristauz of Besi updated the attendees on the advances in 3D Stacking with thermocompression bonding (TCB).

Thermocompression bonding which requires both heat and pressure is contrasted to mass reflow bonding (also simply called solder reflow) where no pressure as to be exerted. The latter is a high productivity process whereas the former is known for slower throughput.  It is usually accepted that TCB is required at pitches less than 40um.

TCB may be done with capillary underfill or more recently with NCP (substrate side) or NCF (chip side) as shown below.

Besi indicates that TCB is being used for Micron HMC production.

IMEC – 3D Technology Depends on Application

Eric Beyne of IMEC examined mapping 3D technology to 3D applications.

For instance,

–        Logic + wide I/O density: high interconnect density

–        Mixed signal/MEMS : lower interconnect density

Interconnect technology options include:

A high bandwidth interconnect bus requires a ref/shielding plane for signal integrity and reduced cross-talk which would mean:

Choices will depend on the interconnect density that is needed.

[added note from IFTLE] All interposer products announced thus far are still requiring the high density dual damascene interconnects.

AMS AG – Sensors for Smart Systems

Martin Schrems of AMS AG reported on “3D Sensor Integration for Smart Systems”. Certainly we would all agree that sensors are a major part of what will make smart systems smart. AMS offers the following as a standard block diagram for a smart system:

For instance, indoor air quality sensors measures standard  temperature, humidity and carbon dioxide (CO2) levels as well as the amount of volatile organic compounds (VOCs), such as smoke, cooking odors, bio-effluence (body odor), outdoor pollutants or human activities. While temperature and humidity are easy to measure, sensors for measuring CO2 (IR absorption) can be expensive.  VOC detection uses micromachined metal oxide semiconductor (MOS) technology to detect a broad range of VOCs while correlating directly with CO2 levels in the room.

The motivation to move to 2.5D packaging is the size reduction advantages.  At this point these systems are still at the R&D conceptual stage.

Asahi Glass – Update on glass for 2.5D Interposers

Asahi Glass is one of the glass producers putting their money where their mouth is in terms of funding R&D and development into the use of glass as a 2.5D interposer material. We have discussed in length their investment into Triton, a start-up looking at manufacturing  commercial glass interposers [ see IFTLE 141 “IFTLE 141 100GB Wide IO memory; AGC Glass Interposers; Nvidia talks stacked memory”]

At the 3D Summit in Grenoble Shin Takahashi of Asahi Glass reviewed the status and challenges of glass interposer activity. Below we can see their listed technical and manufacturing challenges.

With thin silicon (100um) they are now able to create 25-30um tapered TGV (through glass vias) on a 50um pitch.

For via filling, they are looking at both conformal copper plating and copper paste filling where their capabilities are currently 50um dia. on 130um pitch.

Reports on panel based processing, which is viewed as the primary means of lowering the cost structure on interposers, is seen as lacking infrastructure.

Yole Developpement – Wafer Level continues market penetration

During her overview of the industries packaging efforts, Rozalia Beica of Yole indicated that wafer level processing will this year account for 20% of all semiconductor IC wafers.

For all the latest on 3DIC and advanced packaging, stay linked to IFTLE…