According to Yole Développement's new report, Thin Wafer Market & Applications, thinned wafers will be the majority of wafers in the market by 2016 as opposed to today's 27%. They pointed out "the applications that require thin and ultra-thin wafers: MEMS, CMOS Image Sensors, 3D Packaging (incl. Interposers), Memories, RF Devices, Power Devices and LEDs..."
One of the drivers for thin wafers is aggressive Through Silicon Via (TSV) pitch & diameters for high interconnect density. Wafer with TSV inherently become thin after back-grinding, in 3D wafer level packaging cases, the wafer thickness for an active device with TSV is on the order of 50 microns and TSV interposer wafer thickness in 2.5D is typically on the order of 100 microns.
As wafer thickness decreases from the traditional 500μm to 100μm and below, wafer handling challenges arise. The thin wafer, very often warped, or even "potato chip"-like, is less stable and more vulnerable to stresses. The traditional vacuum-grap handling technology meets its limitation when the wafer is sub-300 microns. To address these challenges, wafer handler using Bernoulli principle are available for years but the lack of placement precision due to the nature of this principle makes it hard to be adapted for application requiring high repeatability (such as wafer bonding).
Vortex Design for Thin Wafer
Innovative Robotics launched its first 150mm & 200mm, 50-micron thin wafer handling/flipping robotic solution in 2007; started shipping 300mm/75 microns thin wafer handling 2011. Vortex design principle, similar but more powerful than Bernoulli, is used in these solutions to assure non-contact, non-contamination during handling. The electric-actived non-contact edge grip, with optional self-centering feature, assures a high reliable and repeatable wafer handling solution.
Challenge of MEMS Manufacturing
Micro-electro-mechanical systems (MEMS) technology is a rapidly emerging field with a high growth rate. Many MEMS devices require silicon wafer bonding to create a first level package - for example silicon or glass bonding, which uses the widest range of wafer thicknesses (from 50 microns to 6mm). Innovative Robotics' modularity is the best handling solution for MEMS manufacturing. The IR-820 robot is designed to fit all wafer handlers with none or minimal accessary change. No need to complicate your tool's software development; IR-820 offers a simple and healthy recipe-driven operation to switch between different applications.