Memory, Logic, Power Devices & Image Sensors markets will drive the thin wafers market and related handling technologies
WITH ALMOST ¾ OF THE TOTAL NUMBER OF WAFERS EXPECTED TO BE THINNED BY 2017, TEMPORARY BONDING MARKET WILL INCREASE IN THE COMING YEARS
This Yole Développement report describes why thinner wafers will be needed in the future, especially for consumer applications. Indeed, consumer electronics is a big driver for smaller, higher-performing, lower-cost device configurations for use in various applications, such as memory and wireless devices. These new configurations, in turn, are pushing demand for thin (< 100 µm) and even ultra-thin semiconductor wafers (below 40µm) with the following benefits:
- Reduced thickness and thus thinner packages (in cell phones, packaged dies must be < 1.2mm thick; this number shrinks to1mm for smart phones)
- Wafer thinning is the most efficient approach used for heat dissipation in thermal management
- For 3D integration, thin wafers bring higher through Si vias density, as pitch and dimensions are becoming smaller
However, as wafer thickness decreases to 100µm and below, manufacturing challenges arise. Ultra-thin wafers are less stable and more vulnerable to stress, and the die can be prone to breaking and warping—not only during grinding but also during subsequent processing steps. Yole Développement’s report describes why special thin wafer handling processes (i.e. temporary bonding) are necessary, especially when wafers are dual-side processed or have high topographies.
This report deals not only with the thin wafers market and applications, but also with related processes, equipment, and materials for temporary bonding.
Thin wafer shipment forecasts are analyzed, as there is definitely a growing need for thin wafers (below 100 µm) for numerous applications: 3D ICs, MEMS, CMOS Image Sensors, Power Devices, LEDs, RF Devices, Memory & Logic, Interposers and Photovoltaic. The report shows that, by 2017, the ratio of THIN wafers vs. TOTAL number of wafers (in 300 mm eq.) will be 74%, corresponding to > 80M 12’’ eq. wafers.
Applications are also described in the report. The 2012 market drivers for thin wafers are 3D ICs, and also Power Devices and CIS BSI for ultra-thin wafers. Indeed, the BSI application is the big driver for ultra thin wafers; this application is currently booming. 2011 was a big year for 300 mm wafer bonding tools, thanks to BSI. This application requires ultra thin layers (< 10µ) on 12’’.
Forecasts by wafer thickness are analyzed in the report. In 2017, most of the 12’’ wafers will be 200µm thick for logic application; also, most of the thinned wafers will be in the 10-99µ thickness range. This includes memory, as well as interposers and power device applications.
CURRENTLY LOW IN VALUE, THE TEMPORARY BONDING EQUIPMENT MARKET WILL REACH US$250M BY 2017
Thin wafer handling will enjoy increased importance in the coming years, but as chips get thinner and wafer diameter increases, thinning/handling procedures are required. This implies development in wafer thinning, wafer dicing and wafer temporary bonding.
Yole Développement’s report provides a temporary wafer bonding equipment forecast which shows that 10% of the total thin wafer shipment will experience a temporary bonding step by 2017. So, while temporary bonding equipment is still a small market today, it is expected to grow as the need for thin wafer handling grows. In fact, we estimate the market for temporary bonding tools to be more than $250M by 2017. Currently, shipped bonder/debonders are for Power and 3D ICs applications. However, we believe 3D ICs will become the predominant application for temporary bonders > 2015.
Temporary bonding implies know-how in process and chemistry, and an understanding of the final application requirements. Temporary bonding is a complex technology, requiring an interface material (sometimes called the “Magic” material) that is strong enough to withstand post-processing but which can be easily removed afterwards. As the main concern for temporary bonding materials (wax, tape or glue) is temperature stability, the material must be strong enough to withstand processing steps (metallization, etching, grinding). Another issue is the choice of carrier material. Carrier lifetime depends on its capability to withstand steps such as grinding, etc., and carrier lifetime should be at least tens of times, though this is not yet the case today.