Microelectromechanical device packages with integral heaters

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.

We claim:  
     
         1 . A substrate of a package for packaging a micromirror array device, the substrate comprising: 
 a laminate that comprises a plurality of substrate layers bonded together; and    a heater that is disposed along a periphery of one substrate layer of the plurality of substrate layers and disposed between said substrate layer and another substrate layer of the plurality of substrate layers.    
     
     
         2 . The substrate of  claim 1 , wherein the heater has a zigzag shape.  
     
     
         3 . The substrate of  claim 1 , wherein the substrate layers are ceramic.  
     
     
         4 . The substrate of  claim 1 , wherein the substrate layers are glass.  
     
     
         5 . The substrate of  claim 1 , wherein the heater comprises tungsten.  
     
     
         6 . The substrate of  claim 1 , wherein the plurality of the substrate layers form a cavity in which the micromirror array device is located.  
     
     
         7 . The substrate of  claim 6 , wherein one substrate layer of the plurality of substrate layers is deposited thereon a metallization layer for metalizing at least said substrate layer or a glass frit.  
     
     
         8 . The substrate of  claim 7 , wherein the substrate layer, on which the metallization layer is deposited is the surface layer of the substrate.  
     
     
         9 . The substrate of  claim 6 , wherein the laminate comprises an inlay glass that is transmissive to visible light.  
     
     
         10 . The substrate of  claim 1 , wherein the laminate is a flat plate.  
     
     
         11 . A package, comprising: 
 a first substrate having a heater along a periphery of the top surface of the first substrate and underneath said top surface;    a second substrate above the first substrate;    a semiconductor device or a microelectromechanical system device between the first and second substrate; and    a first sealing medium layer bonding the first substrate and the second substrate together.    
     
     
         12 . The package of  claim 11 , wherein the first sealing medium layer further comprises a glass frit or solderable metallic material that bonds the first and second substrates together.  
     
     
         13 . The package of  claim 11 , wherein the first substrate is a multilayered structure that comprises a plurality of substrate layers.  
     
     
         14 . The package of  claim 11 , wherein the heater has a zigzag shape  
     
     
         15 . The package of  claim 11 , wherein the heater comprises a metallic material.  
     
     
         16 . The package of  claim 15 , wherein the metallic material of the heater is formed by sputtering.  
     
     
         17 . The package of  claim 11 , wherein the microelectromechanical device is a micromirror array device that comprises an array of micromirrors for selectively reflecting light.  
     
     
         18 . The package of  claim 11 , wherein the first substrate is ceramic.  
     
     
         19 . The package of  claim 11 , wherein the second substrate is glass that is transparent to visible light.  
     
     
         20 . The package of  claim 19 , wherein at least one surface of the second glass substrate is deposited thereon an anti-reflection layer for enhancing transmission of visible light through the glass substrate.  
     
     
         21 . The package of  claim 11 , wherein the second substrate further comprises: another heater along a periphery of a surface of the second substrate and underneath said surface of the second substrate.  
     
     
         22 . The package of  claim 11 , wherein the first sealing medium layer is a multilayered structure that further comprises a plurality of solderable metallization layers for metalizing the surface of the first substrate.  
     
     
         23 . The package of  claim 11 , wherein the first sealing medium layer is a solderable metallization layer for metalizing the surface of the first substrate.  
     
     
         24 . The package of  claim 23 , further comprising: 
 a metallic solder layer on the first sealing medium layer; and    a second sealing medium layer that is solderable metallization layer between the metallic solder layer and the second substrate for metalizing a surface of the second substrate, said surface facing the micromirror array device within the cavity of the first substrate.    
     
     
         25 . The package of  claim 11 , further comprises: one or more getters.  
     
     
         26 . The package of  claim 11 , wherein the first substrate has a concave surface forming a cavity, in which the semiconductor or the microelectromechanical device is located.  
     
     
         27 . The package of  claim 11 , wherein the first substrate is a flat plate, on which the semiconductor or the microelectromechanical device is located.  
     
     
         28 . The package of  claim 27 , wherein the package further comprises: a spacer between the first and second substrate; and wherein the first sealing medium layer is between the spacer and the first substrate for bonding the first substrate and the spacer.  
     
     
         29 . The package of  claim 28 , wherein the first sealing medium is a glass frit or a solderable metallic layer.  
     
     
         30 . The package of  claim 29 , wherein the solderable metallic layer that further comprises a first metallization layer for metalizing the surface of the first substrate, a sealing medium layer for bonding the first substrate and the space together and a second metallization layer for metalizing the surface of the spacer.  
     
     
         31 . The package of  claim 28 , wherein the package further comprises a second sealing medium layer between the spacer and the second substrate.  
     
     
         32 . The package of  claim 31 , wherein the second sealing medium is a glass frit or a solderable metallization layer.  
     
     
         33 . The package of  claim 32 , wherein the solderable metallic layer that further comprises a first metallization layer for metalizing the surface of the first substrate, a sealing medium layer for bonding the first substrate and the space together and a second metallization layer for metalizing the surface of the spacer.  
     
     
         34 . The package of  claim 11 , wherein the micromirror array device is a part of a spatial light modulator used in a digital display system.  
     
     
         35 . The package of  claim 11 , wherein the micromirror array device further comprises: 
 an array of micromirrors; and    an array of electrodes and circuitry for electrostatically controlling the micromirrors.    
     
     
         36 . The package of  claim 27 , wherein the micromirror array and the electrodes and circuitry array are formed on one device substrate.  
     
     
         37 . The package of  claim 27 , wherein the micromirror array is formed on a glass substrate that is transparent to visible light; and wherein the electrodes and circuitry array is formed on a wafer.  
     
     
         38 . The package of  claim 11 , further comprising: one or more getters.  
     
     
         39 . The package of  claim 11 , wherein the first substrate has a concave surface that forms a cavity in which the semiconductor device or the microelectromechanical device being located  
     
     
         40 . A method comprising: 
 providing a first package substrate that comprises a heater integral with and along a periphery of one surface of the first substrate;    attaching a semiconductor device or 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; and    bonding the first and second substrate by the melted sealing medium.    
     
     
         41 . The method of  claim 40 , wherein the heater is embedded underneath the surface of the first substrate.  
     
     
         42 . The method of  claim 40 , wherein the microelectromechanical device is a micromirror array device that comprises an array of micromirrors for selectively reflecting light.  
     
     
         43 . The method of  claim 40 , wherein the heater is formed on the surface of the first substrate.  
     
     
         44 . The method of  claim 40 , wherein the first substrate is a multilayered structure that further comprises a plurality of substrate layers.  
     
     
         45 . The method of  claim 40 , wherein the heater is made up of tungsten.  
     
     
         46 . The method of  claim 40 , wherein the heater has an zigzag edge.  
     
     
         47 . The method of  claim 40 , wherein the first sealing medium is a glass frit.  
     
     
         48 . The method of  claim 40 , wherein the first sealing medium is a solderable metallic layer.  
     
     
         49 . The method of  claim 40 , wherein the first sealing medium is an inorganic material.  
     
     
         50 . The method of  claim 49 , wherein the inorganic material is a metal oxide or metalloid oxide.  
     
     
         51 . The method of  claim 49 , wherein the inorganic material is a metal.  
     
     
         52 . The method of  claim 40 , further comprising: 
 placing the semiconductor device or the microelectromechanical device into a cavity defined by the first substrate; and    depositing an anti-stiction material within the cavity.    
     
     
         53 . The method of  claim 52 , wherein the second sealing medium layer is a solderable metallization layer.  
     
     
         54 . The method of  claim 52 , further comprising: 
 forming another heater on in the second substrate such that the heater is along a periphery of one surface of the second substrate;    driving another electric current through the heater on the second substrate.    
     
     
         55 . The method of  claim 54 , wherein the heater in the second substrate is embedded underneath the surface, along the periphery of which the heater is formed.  
     
     
         56 . The method of  claim 55 , wherein the heater is made up of tungsten.  
     
     
         57 . The method of  claim 55 , wherein the heater has a zigzag shape.  
     
     
         58 . The method of  claim 55 , wherein the second substrate is a multilayered structure that further comprises a plurality of layers.  
     
     
         59 . The method of  claim 54 , wherein the first sealing medium layer further comprises: 
 a plurality of solderable metallization layers.    
     
     
         60 . The method of  claim 40 , 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.    
     
     
         61 . The method of  claim 40 , wherein the first substrate has a concave surface that forms a cavity, in which the semiconductor device or the microelectromechanical device is placed.  
     
     
         62 . The method of  claim 40 , wherein the second substrate comprises an inlay glass window that is transparent to visible light.  
     
     
         63 . The method of  claim 40 , further comprising: 
 depositing a rectangular light blocking frame along the circumference of the second substrate before bonding the first and the second substrate.    
     
     
         64 . The method of  claim 40 , 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.  
   
     
     
         65 . The method of  claim 64 , wherein the second sealing medium layer is a glass frit.  
     
     
         66 . The method of  claim 64 , wherein the second sealing medium layer is a solderable metallic material.  
     
     
         67 . The method of  claim 64 , 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.  
     
     
         68 . The method of  claim 67 , further comprising: 
 driving another electric current through the heater in the second substrate.    
     
     
         69 . The method of  claim 64 , 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.    
     
     
         70 . The method of  claim 69 , wherein the first or second metallization layer is a multilayered structure.  
     
     
         71 . The method of  claim 40 , 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.    
     
     
         72 . The method of  claim 40 , 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° degrees or more.    
     
     
         73 . The method of  claim 40 , 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° degrees or more.    
     
     
         74 . The method of  claim 40 , 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° to 300° degrees.    
     
     
         75 . The method of  claim 40 , wherein the first sealing medium has a melting temperature around 300° degrees or less.  
     
     
         76 . The method of  claim 40 , wherein the first sealing medium has a melting temperature around 200° degrees or less.  
     
     
         77 . The method of  claim 40 , 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.  
     
     
         78 . A system, comprising: 
 a light source for providing light;    a spatial light modulator for selectively modulating light from the light source so as to form an image on a display target, wherein the spatial light modulator further comprises: 
 a first package substrate having a heater along a periphery of the top surface of the first package substrate and embedded underneath said top surface for generating heat;  
 a micromirror array device held on the first package substrate;  
 a second package substrate on the first package substrate; and  
 a first sealing medium layer bonding the first package substrate and the second package substrate together;  
   a condensing optical element for directing the incident light onto the spatial light modulator;    a display target; and    a projection optic element for directing the modulated light onto the display target.    
     
     
         79 . The system of  claim 78 , further comprising: 
 a color wheel having at least three color regions, each corresponding to one of the three primary colors including red, blue and green.    
     
     
         80 . The system of  claim 78 , wherein the first package substrate has a concave surface that forms a cavity, in which the micromirror array device is located.  
     
     
         81 . The system of  claim 78 , wherein the first package substrate further comprises a plurality of substrate layers.  
     
     
         82 . The system of  claim 78 , wherein the first package substrate is ceramic.  
     
     
         83 . The system of  claim 78 , wherein the heater in the first package substrate has a zigzag shape.  
     
     
         84 . The system of  claim 78 , wherein the first sealing medium layer is a glass frit.  
     
     
         85 . The system of  claim 78 , wherein the heater in the first package substrate is tungsten.  
     
     
         86 . The system of  claim 78 , wherein the second substrate is glass that is transparent to visible light.  
     
     
         87 . The system of  claim 86 , wherein the glass substrate is coated with an anti-reflection layer for enhancing transmission of incident light through the glass substrate.  
     
     
         88 . The system of  claim 78 , wherein the second package substrate further comprises another heater along a periphery of one surface of the second package substrate and embedded underneath said surface of the second package substrate.  
     
     
         89 . The system of  claim 78 , wherein the micromirror array device further comprises: 
 an array of micromirrors for selectively reflecting the incident light; and    an array of electrodes and circuitry for electrostatically controlling the micromirrors.    
     
     
         90 . The system of  claim 89 , wherein the array of micromirrors and the array of electrodes and circuitry are formed on one device substrate;  
     
     
         91 . The system of  claim 90 , wherein the array of micromirrors and the array of electrodes and circuitry are formed on separate device substrates.  
     
     
         92 . The system of  claim 78 , wherein the spatial light modulator further comprises: 
 a soldering layer deposited on the first sealing medium; and    a second sealing medium deposited on the soldering layer.    
     
     
         93 . The system of  claim 92 , wherein the first sealing medium layer is a solderable metallization layer for metalizing the surface of the first package substrate; and wherein the second sealing medium is a solderable metallization layer for metalizing the surface of the second package substrate.  
     
     
         94 . The system of  claim 93 , wherein the first or the second sealing medium layer is a multilayered structure.