Handbook of Silicon Based MEMS Materials and Technologies

37.3. Wafer Bonders

Selection of the appropriate wafer-bonding process and subsequently the suitable type of bonding equipment for specific products is of great importance. Table 37.1 summarizes some of the main items which need to be considered in selecting bond technology and equipment.

Table 37.1. Parameters influencing bond technology selection

Criteria	Item	Selection
Materials restrictions	Materials chemistryMechanical propertiesBond process temperature	Surface pre-treatment Intermediate layers (if used) Bond force Bonder tooling Prevent destruction of structures (e.g., metallization) Minimize stress induced by different thermal expansion coefficients of materials
Specific device requirements	Alignment accuracyHermeticityThermal conductivityTransparency ...