Abstract: Techniques for bonding substrates are disclosed. According to one aspect of the techniques, an index bonding is provided to ensure that non-flatness of substrates is compensated when two substrates are bonded together so as to minimize possible dynamic imbalance of a disc. According to another aspect of the techniques, a dynamic alternating electric field bonding is provided to eliminate bubbles from a type of glue used to bond two substrates, wherein a power source is used to generate a dynamic alternating electromagnetic field in accordance with the substrates and/or the characteristics of the glue.