Laser sealing methods for closing ventholes of micromecahnical devices
AssigneeRobert Bosch GmbH
InventorsBo Cheng, Holger Rumpf, Jens Frey, Charles Tuffile, Stephanie Karg, Tobias Joachim Menold
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Abstract
A venthole of a micromechanical device is sealed with laser irradiation. A micromechanical device has a substrate, such as silicon. The substrate has an upper surface, and defines a venthole leading to a chamber that contains a device, and a trench extending downward from the upper surface and located offset from the venthole. A laser pulse is applied to the substrate at or within the trench. This causes a portion of the substrate located below the upper surface to melt and travel laterally to close off and seal the venthole laterally from beneath the upper surface.
Claims11
A method of sealing a venthole of a micromechanical device, the method comprising:
- providing a micromechanical device having a substrate, the substrate having an upper surface, and the substrate defining:
- a venthole leading to a chamber, and
- a trench extending downward from the upper surface and located offset from the venthole;
- and
- applying a laser pulse to the trench to perform laser irradiation on the substrate, wherein the laser irradiation is confined to the trench and does not intersect the venthole, wherein the applying causes a portion of the substrate located below the upper surface to melt and seal the venthole laterally and from beneath the upper surface, and wherein the applying does not melt the upper surface of the substrate at the venthole and seals the venthole without melting the upper surface of the substrate at the venthole.
Dependencies are inferred from the claim text.