Abstract:
A method for curing an epoxy-based photoresist uses a continuously varying temperature profile, to continuously raise the kinetic energy of the monomers involved in the curing process, allowing them to cross-link. By using the continuously varying temperature profile, the maximum temperature to achieve a more completely cured film is reduced, as is the total processing time. In addition, curing using the continuously varying temperature profile is a single step method, rather than a multi-step method of the prior art, significantly simplifying the process flow for producing the cured structures. The cured structures may have mechanical properties which render them suitable as functional elements of various MEMS devices, including rigid, dielectric tethers used in MEMS thermal switches, for example.
Abstract:
A MEMS hysteretic thermal device may have a cantilevered beam which bends about one or more points in at least two substantially different directions. In one exemplary embodiment, the MEMS hysteretic thermal device is made from a first segment coupled to an anchor point, and also coupled to a second segment by a joint. Heating two respective drive beams causes the first segment to bend in a direction substantially about the anchor point and the second segment to bend in a direction substantially about the joint. By cooling the first drive beam faster than the second drive beam, the motion of the MEMS thermal device may be hysteretic. The MEMS hysteretic thermal device may be used for example, as an electrical switch or as a valve or piston.
Abstract:
A method for forming through hole vias in a substrate uses a partially exposed seed layer to plate the bottom of a blind trench formed in the front side of a substrate. Thereafter, the plating proceeds substantially uniformly from the bottom of the blind hole to the top. To form the through hole, the rear face of the substrate is ground or etched away to remove material up to and including the dead-end wall of the blind hole.
Abstract:
A micromechanical particle sorting chip uses an actuator divided into two parts to direct a component of interest into one of a plurality of possible exit paths, based on detection of a fluorescent signal emanating from the component of interest. The two-part actuator may include a force-generating portion and a microactuator portion. The microactuator portion may be disposable, whereas the force-generating portion may be reuseable. By bringing the force-generating portion into proximity to the microactuator portion, the microactuator is induced to move, thereby separating the component of interest from the rest of the fluid stream. The force-generating portion and the microactuator portion may be optimized and fabricated separately, thereby leading to faster, more reliable and less expensive particle sorting.
Abstract:
A microfabricated cross flow filter may have multiple filtration stages. The filtration stages may include microfabricated filter barriers and gaps created in a substrate, thereby allowing very tight tolerances in the filter barrier and gap dimensions to be maintained. Using the microfabrication techniques, the filter barriers can be made having arbitrary shapes, and arranged at an angle or curved with respect to the flow direction, making the pressure drop across the filtration stage more uniform in the cross flow direction.
Abstract:
The invention describes a method and apparatus for deploying micromachined actuators in a plane which is orthogonal to the original fabrication plane of the devices. Using batch-processing, photolithographic procedures known in the micromachined electro-mechanical system (MEMS) art, a plurality of devices is constructed on a suitable substrate. The devices are then separated one from another by sawing and dicing the original fabrication wafer. The devices are rotated into an orthogonal orientation and affixed to a second wafer. The second wafer also contains circuitry for addressing and manipulating each of the devices independently of the others. With this method and apparatus, arrays of actuators are constructed whose plane of actuation is perpendicular to the plane of the array. This invention is useful for constructing N×M fiber optic switches, which direct light from N input fibers into M output fibers.
Abstract:
Systems and methods for forming an electrostatic MEMS plate switch include forming a deformable plate on a first substrate, forming the electrical contacts on a second substrate, and coupling the two substrates using a hermetic seal. A two-fold symmetric switch may be formed by a primary, secondary, and optionally tertiary set of voids formed in the movable plate. These voids may define the spring beams which provide a stable and reliable restoring force to the switch.
Abstract:
Systems and methods for forming a compact gas sensor include using a lithographically fabricated high Q resonator coupled to at least one of a Gunn diode and an IMPATT diode. The resonator may include a plurality of cavities filled with a sample gas. A detector coupled to the resonator may measure the amplitude of the emitted mm wave radiation.
Abstract:
The method described here uses gray scale lithography to form curve surfaces in photoresist. These surfaces can be of arbitrary shape since the remaining resist following exposure and develop is dependent on the exposure dose, which is controlled precisely by the opacity of the photo-mask. The process may include a silicon etch step, followed by a photoresist etch step to form an etching cycle. Each etch cycle may form a pair of substantially orthogonal stepped surfaces, with a characteristic “rise” and “run.”
Abstract:
We describe here a scanning optical beam that is comprised of no moving parts The device includes a plurality of microfabricated beam shaping elements disposed in an array wherein each microfabricated beam shaping element is registered with a microfabricated light source but has an optical axis that is offset from the optical axis of the light source by a different amount, wherein the amount is a function of the distance from a center of the arrays. A method of operating the scanning optical beam is also described.