Abstract
Using the semiconductor technology to manufacture an accelerometer (or optical scanner device), there is a procedure that a chip (or glass) is covered on another chip having accelerometer thereon. It is necessary that vacuum is maintained between the two chips in order to achieve the quality criteria of the accelerometer (or optical scanner device). The present invention discloses a method that the reaction between molten solder and UBM (under bump metallurgy) and the surface tension of the molten solder are utilized to achieve the self-alignment, sealing and vacuum packaging of the two chips.