Abstract: A wire-based heating element is provided having first and second portions twisted about each other such that magnetic flux emitted from one portion is substantially cancelled by magnetic flux emitted from the other portion. A bonding material that fixedly connects the two portions of the heating element and restricts their movement relative to each other to thereby maximize the cancellation of magnetic flux. A substrate-based heating element is also provided having traces on opposed sides of a substrate and overlying each other to cancel magnetic flux. Electrical connection pads are located on the same side of the substrate, and the second trace extends passed the first trace to connect to the second connection pad. A lead connected to the first connection pad overlies the portion of the second trace that extends to the second connection pad to thereby cancel magnetic flux emissions from this portion of the second trace.

Abstract: A wire-based heating element is provided having first and second portions twisted about each other such that magnetic flux emitted from one portion is substantially cancelled by magnetic flux emitted from the other portion. A bonding material that fixedly connects the two portions of the heating element and restricts their movement relative to each other to thereby maximize the cancellation of magnetic flux. A substrate-based heating element is also provided having traces on opposed sides of a substrate and overlying each other to cancel magnetic flux. Electrical connection pads are located on the same side of the substrate, and the second trace extends passed the first trace to connect to the second connection pad. A lead connected to the first connection pad overlies the portion of the second trace that extends to the second connection pad to thereby cancel magnetic flux emissions from this portion of the second trace.

Abstract: A process is provided for protecting, containing, and/or completing fragile microelectronic and microelectromechanical (MEM) structures on a low conductivity substrate during anodic wafer bonding of a covering wafer. The wafer includes raised areas that contact the substrate at selected bonding regions to support the wafer as a covering structure over the substrate. The covering wafer includes additional raised areas, such as pillars or posts, that contact selected electric circuit lines on the substrate to form temporary shorts through the wafer. During anodic bonding of the wafer to the substrate, the temporary shorts maintain the connected circuit lines and microstructures at nearly the same electric potential to prevent unwanted arcing and electrostatic forces that could damage the fragile structures. The pillars or posts can be formed at the same time as the raised bonding areas, but on unwanted and otherwise unused portions of the covering wafer.

Abstract: A dissolved wafer process is modified by providing an etch control seal around the perimeter of an etch resistant microstructure, such as a micromechanical or microelectromechanical device, formed on a first substrate. The microstructure is defined and shaped by a surrounding trench in the first substrate. Selected areas of the microstructure and the first substrate are bonded to an etch resistant second substrate. The selected bonding areas may comprise raised areas of the first substrate, or raised areas of the second substrate corresponding to the selected bonding areas of the first substrate. A bonded area forming a ring extending around the perimeter of the microstructure and its defining trench forms an etch control seal. The first substrate of the bonded assembly is dissolved in a selective etch so that the etch resistant microstructure remains attached to the second substrate only at the bonded areas.

Abstract: A dissolved wafer micromachining process is modified by providing an etch control seal around the perimeter of a heavily doped micromechanical structure formed on a substrate. The micromechanical structure is fabricated on a wafer using conventional methods including the formation of a trench that surrounds and defines the shape of the micromechanical structure in the substrate. The etch control seal comprises a portion of the substrate in the form of a raised ring extending around the perimeter of the micromechanical structure and its defining trench. Selected raised areas of the heavily doped micromechanical structure and the top of the raised etch control seal are bonded to a second substrate. A selective etch is then used to dissolve the first substrate so that the heavily doped micromechanical structure remains attached to the second substrate only at the bonded areas.