IP Library › Granted Patent US 9,056,764
Granted Patent B2
US 9,056,764 · App. 11/872,825 · Granted Jun 16, 2015

Microelectromechanical device packages with integral heaters

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Quick Facts
Patent No.
US 9,056,764
App. No.
11/872,825
Granted
Jun 16, 2015
Kind
B2
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.

Claims (36)

1. 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.

2. The method of claim 1 , further comprising applying external pressure to the cover substrate during the bonding.

3. The method of claim 1 , wherein the heater is located at a distance of about 7 mm below the upper surface of the second substrate layer.

4. The method of claim 1 , wherein the electric current is driven through the heater by applying a voltage of 40-100 volts to the heater.

5. The method of claim 4 , wherein the electric current is driven through the heater by applying a voltage of about 70 volts to the heater.

6. The method of claim 4 , wherein the heater is formed in a zigzag configuration.

7. The method of claim 6 , wherein the zigzag configuration terminated in two leads, and the voltage is applied across the two leads.

8. The method of claim 7 , wherein the first and second metallic films comprise at least one of aluminum, gold or nickel.

9. The method of claim 8 , wherein the first and second metallic films are deposited by sputtering.

10. The method of claim 7 , 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.

11. The method of claim 10 , wherein the top metallic layer comprises Tu, Ni or Au.

12. The method of claim 10 , wherein the top metallic layer comprises Au, Cr or other noble metal.

13. The method of claim 10 , wherein the metal oxide layer comprises CrO 2 or TiO 2 , the at least one intermediate metallic layer includes a first intermediate layer comprising Cr or Ti and a second intermediate layer comprising Ni, and the top metallic layer comprises Au.

14. The method of claim 1 , wherein the heater is formed in a zigzag configuration.

15. The method of claim 14 , wherein the zigzag configuration terminated in two leads, and the voltage is applied across the two leads.

16. The method of claim 1 , wherein the first and second metallic films comprise at least one of aluminum, gold or nickel.

17. The method of claim 1 , wherein the first and second metallic films are deposited by sputtering.

18. 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.

19. The method of claim 18 , wherein the top metallic layer comprises Ti, Ni or Au.

20. The method of claim 18 , wherein the top metallic layer comprises Au, Cr or other noble metal.

21. The method of claim 18 , wherein the metal oxide layer comprises CrO 2 or TiO 2 , the at least one intermediate metallic layer includes a first intermediate layer comprising Cr or Ti and a second intermediate layer comprising Ni, and the top metallic layer comprises Au.

22. The method of claim 1 , wherein the cover substrate comprises glass or quartz, and the device is a digital micromirror device (DMD).