| XSiL Launches Next Generation of Laser Dicer for Thin Wafers |
| Industry’s first laser-dicing tool specifically designed for thin silicon wafers |
Dublin, Ireland, March 30, 2007 - XSiL, the world-leading provider of innovative laser micro-machining systems, today announced it will launch, at SEMICON West, its new laser dicing system specifically designed to process thin silicon wafers.
Practically every silicon wafer produced must be singulated or diced. Laser dicing technology is presently not competitive for standard thickness dicing — it is with thin silicon dicing that laser systems have a competitive advantage. There is a growing percentage of the market that produces thin silicon wafers, and the thickness of these wafers is reducing year-on-year. The primary drivers for this production are mobile computing and wireless communications. Flash & multi-chip memories are the largest device sector to adopt thin wafers. This is driven by the need for greater storage, in smaller spaces.
Present techniques for singulating thin silicon wafers are facing increasing difficulties. Because of increasing cost pressures, chip manufacturers are actively seeking alternate solutions. In response to these semiconductor trends and to meet the demanding requirements of thin wafer dicing, XSiL has developed the X300D+. The primary strengths of this laser-based system are high throughput and high die strength (a yield factor). When coupled with low consumable costs, it provides a competitive CoO. The machine processes have been validated with key chip manufacturers in the industry space.
The X300D+ includes a wash station, where a non-ionic, water-soluble coating is dispensed onto the wafer and spin-coated for uniform coverage. This provides a low-cost, high-performance protection to the wafer to prevent and reduce risk of wafer contamination. The coating’s main function is protection — ensuring yield is maintained. This coating was selected after rigorous process development and trials. Due to its water-soluble nature, it does not require complex removal or treatment methods as may be the case with other, different coating formulations.
After coating, the wafer is diced using a high-powered UV DPSS laser at 355nm. The processes and techniques used in this dicing step provide the ability to machine the silicon and DAF with minimal damage and no chipping – ensuring high yield. Using a combination of laser and scanning galvanometers, this dicing process reaches high speed. This speed scales upwards as wafers get thinner. Quality and speed are inversely correlated. No DI water is used in the dicing process and laser diode replacement is of the order of years.
The third process step is wafer cleaning inside the wash station. Here, the coating and debris are removed, providing a clean diced wafer. This process step is performed in parallel to other tasks to maximize throughput. The level of water consumption is minimized to the order of ~1 litre per wafer.
The final process step is an innovative low-cost dry-etch process called MaxFlex™. It has been developed and designed for thin diced wafers and its sole purpose it to increase overall device yield. It performs a stress-relieving function on the silicon sidewall of each and every singulated die on the wafer. It does this by etching or removing, in a selective fashion, up to 5um of silicon. The net result is die strength enhancement – directly improving device and package yield. |
