Common Die Preparation-related Failure Mechanisms:


Die Lifting - detachment of the die from the die pad or cavity. Wafer backside contamination during die preparation may inhibit good adhesion between the die backside and the die attach material. Other Common Causes of Die Lifting: contamination on the die pad or cavity, excessive die attach voids, incomplete die attach coverage, inadequate die attach curing      


Die Cracking - occurrence of fracture anywhere in the die.  Incorrect wafer saw and washing parameters can result in microcracks in the wafers, which can propagate into larger die cracks during later stages of the assembly process. Other Common Causes of Die Cracking: excessive die attach voids, die overhang or insufficient die attach coverage, excessive die ejection force on the wafer tape


Die Scratching - inducement of any mechanical damage on the die, as when an operator scratches a die with tweezers due to mishandling. Die scratches can also result from mishandling of wafers during the die preparation process. Other Common Causes of Die Scratching: insufficient operator training, disorderly workplace, use of improper tools


Die Metallization Smearing - depression or deformation of any metal line on the die surface. Common Causes: dirty or worn-out die attach pick-and-place tool, wafer mishandling


Die Corrosion - corrosion of the metallization and other components of the die. Common Causes: corrosive contaminants on the wafer tape or rinsing water


Die Contamination - contamination of the die surface with silicon dust or foreign material that may be attached either by electrostatic, mechanical, or chemical means. Common Causes: contaminated rinsing water; static charge



Fig. 1.  Photos of Wafer Saw Systems


Front-End Assembly Links:  Wafer Backgrind Die Preparation Die Attach Wirebonding Die Overcoat

Back-End Assembly Links:  Molding Sealing Marking DTFS Leadfinish          

See Also:  IC ManufacturingAssembly Equipment




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