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US 9,056,764 B2Granted
Microelectromechanical device packages with integral heaters
AssigneeTexas Instruments Incorporated
InventorTerry Tarn
Life of this patent
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Abstract
A microelectromechanical device package with integral a heater and a method for packaging the microelectromechanical device are disclosed in this invention. The microelectromechanical device package comprises a first package substrate and second substrate, between which a microelectromechanical device, such as a micromirror array device is located. In order to bonding the first and second package substrates so as to package the microelectromechanical device inside, a sealing medium layer is deposited, and heated by the heater so as to bond the first and second package substrates together.
Claims22
A method comprising:
- providing a packaging substrate having a first ceramic or glass substrate layer with a concave upper surface that forms a cavity, a second ceramic or glass substrate layer with a lower surface joined to the first layer upper surface peripherally surrounding the cavity and with an upper surface, and a heater comprising a metallic film formed integrally with the packaging substrate between the joined lower first and upper second substrate layer surfaces, wherein the heater is located at a distance of 1-10 mm below the upper surface of the second substrate layer;
- providing a cover substrate comprising transparent material at least in a portion configured to overlie the cavity when the cover substrate is joined to the packaging substrate;
- depositing a first metallic film layer peripherally on a lower surface of the cover substrate;
- depositing a second metallic film layer peripherally of the cavity on the upper surface of the packaging substrate;
- attaching a microelectromechanical system (MEMS) device within the cavity;
- and
- bonding the cover substrate peripherally to the packaging substrate so as to enclose the device within the cavity between the bonded cover and packaging substrates;
- wherein the bonding comprises disposing a metallic soldering material between the first and second metallic film layers, the metallic soldering material having a soldering temperature less than a melting temperature of the metallic film layers;
- and applying heat locally by driving an electric current through the heater to melt the soldering material without melting the metallic film layers and without raising a temperature of the device to the soldering temperature, wherein the soldering temperature is less than 300° C. and wherein the heat is applied without raising the temperature of the device to a temperature of 70° C.
6 more elements
A method comprising:
- providing a packaging substrate having a first ceramic or glass substrate layer with a concave upper surface that forms a cavity, a second ceramic or glass substrate layer with a lower surface joined to the first layer upper surface peripherally surrounding the cavity and with an upper surface, and a heater comprising a metallic film formed integrally with the packaging substrate between the joined lower first and upper second substrate layer surfaces;
- providing a cover substrate comprising transparent material at least in a portion configured to overlie the cavity when the cover substrate is joined to the packaging substrate;
- depositing a first metallic film layer peripherally on a lower surface of the cover substrate;
- depositing a second metallic film layer peripherally of the cavity on the upper surface of the packaging substrate;
- attaching a microelectromechanical system (MEMS) device within the cavity;
- and
- bonding the cover substrate peripherally to the packaging substrate so as to enclose the device within the cavity between the bonded cover and packaging substrates;
- wherein the bonding comprises disposing a metallic soldering material between the first and second metallic film layers, the metallic soldering material having a soldering temperature less than a melting temperature of the metallic film layers;
- and applying heat locally by driving an electric current through the heater to melt the soldering material without melting the metallic film layers and without raising a temperature of the device to the soldering temperature, wherein the first and second metallic films comprise a metal oxide layer, at least one intermediate metallic layer formed over the metal oxide layer, and a top metallic layer.
6 more elements
Dependencies are inferred from the claim text.