Patent ID: 6124145
Filing Date: 2000-09-26
Classification: G02B

Abstract:
A method of microfabricating a hermetically sealed gas-filled chamber which contains a gas having a preselected concentration such that the pressure within the chamber is equal to a preselected value P.sub.c when the temperature of the chamber is at a preselected temperature T.sub.0, the gas-filled chamber being microfabricated from a silicon substrate comprising one or more silicon wafers, and a glass wafer bonded to the silicon substrate such that a gas-filled cavity is located adjacent the interface between the silicon substrate and the glass wafer, the method of microfabricating the gas-filled chamber comprising:etching a cavity in the silicon substrate, the cavity being adjacent and surrounded by an anodic bonding surface on the silicon substrate;placing the silicon substrate with the etched cavity within a gas-filled anodic bonding environment, the gas-filled anodic bonding environment containing a concentration of gas substantially maintained at an anodic bonding temperature T.sub.ab and an anodic bonding pressure P.sub.ab, wherein said bonding pressure P.sub.ab is substantially equal to P.sub.ab =P.sub.c (T.sub.ab /T.sub.0) where T.sub.ab and T.sub.0 are absolute temperature values and P.sub.ab and P.sub.c are absolute pressure values and P.sub.c is the preselected pressure value within the chamber when the chamber is at the preselected temperature T.sub.0 ; andanodic bonding the glass wafer to the anodic bonding surface on the silicon substrate while the silicon substrate with the etched cavity is located within the gas-filled anodic bonding environment at temperature T.sub.ab and pressure P.sub.ab, the anodic bonding in the gas-filled anodic bonding environment being implemented by aligning the glass wafer with the bonding surface of the silicon substrate to form a bonding interface between the glass wafer and the silicon substrate and contemporaneously capturing gas from the gas-filled anodic bonding environment within the cavity, and thereafter applying a bonding voltage across the bonding interface between the glass wafer and the silicon substrate while the glass wafer and the silicon substrate are aligned for bonding within the gas-filled anodic bonding environment to bond the interface and hermetically seal the selected concentration of gas therein.