Microelectromechanical device packages with integral heaters
View Patent ↗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.
1. A method comprising:
providing a first substrate that is ceramic and comprises a heater laminated between first and second ceramic layers of the first ceramic substrate;
attaching a silicon substrate having formed thereon a microelectromechanical device to the first substrate;
placing a second substrate on the first substrate with a first sealing medium layer therebetween;
driving an electric current through the heater so as to generate heat for melting the first sealing medium;
bonding the first and second substrate by the melted first sealing medium;
placing the semiconductor device or the microelectromechanical device into a cavity defined by the first substrate;
depositing an anti-stiction material within the cavity;
forming another heater on in the second substrate such that the heater is along a periphery of one surface of the second substrate; and
driving another electric current through the heater on the second substrate.
2. The method of claim 1 , wherein the heater is embedded underneath the surface of the first substrate.
3. The method of claim 1 , wherein the microelectromechanical device is a micromirror array device that comprises an array of micromirrors for selectively reflecting light.
4. The method of claim 1 , wherein the heater is formed on the surface of the first substrate.
5. The method of claim 1 , wherein the heater is made up of tungsten.
6. The method of claim 1 , wherein the heater has a zigzag edge.
7. The method of claim 1 , wherein the first sealing medium is a glass frit.
8. The method of claim 1 , wherein the first sealing medium is a solderable metallic layer.
9. The method of claim 1 , wherein the first sealing medium is an inorganic material.
10. The method of claim 9 , wherein the inorganic material is a metal oxide or metalloid oxide.
11. The method of claim 9 , wherein the inorganic material is a metal.
12. The method of claim 1 , wherein the first sealing medium layer is a solderable metallization layer.
13. The method of claim 1 , wherein the heater in the second substrate is embedded underneath the surface, along the periphery of which the heater is formed.
14. The method of claim 13 , wherein the heater is made up of tungsten.
15. The method of claim 13 , wherein the heater has a zigzag shape.
16. The method of claim 13 , wherein the second substrate is a multilayered structure that further comprises a plurality of layers.
17. The method of claim 1 , wherein the first sealing medium layer further comprises:
a plurality of solderable metallization layers.
18. The method of claim 1 , further comprising:
during driving the electric current through the heater in the first substrate, applying a pressure on the first and second substrate so as to bonding the first and second substrate.
19. The method of claim 1 , wherein the first substrate has a concave surface that forms a cavity, in which the semiconductor device or the microelectromechanical device is placed.
20. The method of claim 1 , wherein the second substrate comprises an inlay glass window that is transparent to visible light.
21. The method of claim 1 , further comprising:
depositing a rectangular light blocking frame along the circumference of the second substrate before bonding the first and the second substrate.
22. The method of claim 1 , wherein the first substrate is flat; and wherein the method further comprises:
before bonding the first and second substrate,
placing a spacer on the deposited first sealing medium layer and between the first and second substrate; and
depositing a second sealing medium layer between the spacer and the second substrate.
23. The method of claim 22 , wherein the second sealing medium layer is a glass fit.
24. The method of claim 22 , wherein the second sealing medium layer is a solderable metallic material.
25. The method of claim 22 , wherein the second substrate further comprises another heater formed along a periphery of one surface of the second substrate and embedded underneath said surface of the second substrate.
26. The method of claim 25 , further comprising:
driving another electric current through the heater in the second substrate.
27. The method of claim 22 , further comprising:
depositing a first metallization layer on a surface of the spacer between the spacer and the second substrate for metalizing the surface of the spacer;
depositing a solder layer between the first metallization layer and the second substrate; and
depositing a second metallization layer along a lower surface of the second substrate, said lower surface of the second substrate facing the solder layer and the first substrate.
28. The method of claim 27 , wherein the first or second metallization layer is a multilayered structure.
29. The method of claim 1 , further comprising:
providing a light source for emitting light shining on the micromirror array device;
providing a condensing optic element along a path of the light emitted from the light source and shining on the micromirror array device for directing the light onto the micromirror array device;
selectively reflecting the light, by the micromirrors of the micromirror array device, onto a display target and;
providing a projection optic element along a path of the reflected light towards the display target.
30. The method of claim 1 , wherein the step of driving the electric current through the heater further comprises:
driving the electric current through the heater so as to heat the surface of the first substrate around 300° C. or more.
31. The method of claim 1 , wherein the step of driving the electric current through the heater further comprises:
driving the electric current through the heater so as to heat the surface of the first substrate around 200° C. or more.
32. The method of claim 1 , wherein the step of driving the electric current through the heater further comprises:
driving the electric current through the heater so as to heat the first sealing medium to a temperature from 100° C. to 300° C.
33. The method of claim 1 , wherein the first sealing medium has a melting temperature around 300° C. or less.
34. The method of claim 1 , wherein the first sealing medium has a melting temperature around 200° C. or less.
35. The method of claim 1 , wherein the semiconductor and the electromechanical device is at a location having a temperature around 70° degrees or less when driving the electric current through the heater.