dicing

Dicing is the process of **cutting a processed semiconductor wafer into individual dies** (chips) after wafer-level testing is complete. Each die is then picked, packaged, and shipped as a finished product. **Dicing Methods** **Blade Dicing**: A thin diamond-impregnated saw blade spinning at **30,000-60,000 RPM** cuts through the wafer along the scribe lines (streets) between dies. Most common method. Street width: **50-100μm**. Cutting speed: **50-300 mm/s**. Creates mechanical stress and chipping at the cut edge. **Laser Dicing**: A focused laser beam scribes or ablates the wafer material along the streets. Two approaches: **laser full-cut** (laser cuts completely through) or **stealth dicing** (laser creates internal damage layer, then tape expansion breaks the wafer along the damage—cleaner edges, narrower streets). **Plasma Dicing**: Deep reactive ion etch (DRIE) removes street material using plasma. Enables the **narrowest streets** (< 10μm), highest throughput for thin wafers, and no mechanical damage. Best for thin wafers (< 100μm) and small dies. **Dicing Process Flow** **Step 1**: Mount wafer onto dicing tape (sticky UV-release film) on a metal frame. **Step 2**: Align streets using the dicer's pattern recognition camera. **Step 3**: Cut all streets in X direction, then rotate 90° and cut Y direction. **Step 4**: Clean cut wafer (DI water spray removes particles and debris). **Step 5**: UV exposure releases tape adhesion. **Step 6**: Individual dies picked from tape by die bonder. **Key Considerations** • **Kerf width**: Material lost to the blade cut (~30-50μm for blade, ~10μm for laser). Narrower kerf = more dies per wafer • **Chipping**: Blade dicing creates micro-chips at the die edge that can propagate as cracks—controlled by blade recipe and wafer thickness • **Thin wafers**: Wafers ground to < 100μm are fragile. Stealth/plasma dicing preferred to avoid cracking • **Die strength**: Dicing-induced edge damage reduces die fracture strength, which matters for automotive and reliability-critical applications