Method and apparatus for an integrated laser beam scanner using a carrier substrate

Abstract

An solid state scanning system having a single crystal silicon deflection mirror and scanning mirror is integrated with a light source. Separation of the micro-electro-mechanical systems and light emitters on separate substrates allows the use of flip-chip and solder bump bonding techniques for mounting of the light sources. The separate substrates are subsequently full wafer bonded together to create an integrated solid state scanning system.

What is claimed is:  
     
       1. An integrated laser beam scanning structure comprising: 
       a first wafer having a first surface and a second surface, said wafer having a recess piercing said first surface and said second surface;  
       a layer having a first region and a second region, said layer being attached to said first surface;  
       a deflecting mirror fashioned from said first region of said layer;  
       a torsional mirror fashioned from said second region of said layer;  
       a second wafer having a first side; and  
       a light source mounted on said first side of said second wafer, said first side of said second wafer being attached to said second surface of said first wafer such that said light source occupies said recess  
       whereby a light beam emitted from said light source is deflected by said deflecting mirror onto said torsional mirror.  
     
     
       2. The structure of  claim 1  wherein said first wafer is a silicon on oxide wafer. 
     
     
       3. The structure of  claim 1  wherein said layer is a single crystal silicon layer. 
     
     
       4. The structure of  claim 1  wherein said light source is a semiconductor light emitter. 
     
     
       5. The structure of  claim 4  wherein said semiconductor light emitter is mounted on said first side of said second wafer using solder bumps. 
     
     
       6. The structure of  claim 4  wherein said semiconductor light emitter is a VCSEL chip. 
     
     
       7. The structure of  claim 1  wherein said recess is deep reactive ion etched. 
     
     
       8. The structure of  claim 1  wherein said torsional mirror is actuated by a pair of electrodes. 
     
     
       9. The structure of  claim 1  wherein said torsional mirror is actuated by a thin film coil. 
     
     
       10. The structure of  claim 1  wherein a ferromagnetic thin film coil is attached to said torsional mirror. 
     
     
       11. The structure of  claim 1  wherein a thin film coil is attached to said torsional mirror. 
     
     
       12. A method for making an integrated laser beam scanner comprising the steps of: 
       providing a first wafer having a first surface and a second surface, said wafer having a recess piercing said first surface and said second surface;  
       attaching a layer having a first region and a second region to said first surface of said first wafer;  
       fashioning a deflecting mirror from said first region of said layer;  
       fashioning a torsional mirror from said second region of said layer;  
       providing a second wafer having a first side, said second wafer having a light source mounted on said first side; and  
       attaching said first side of said second wafer to said second surface of said first wafer such that said light source occupies said recess  
       whereby a light beam emitted from said light source is deflected by said deflecting mirror onto said torsional mirror.  
     
     
       13. The method of  claim 12  wherein said layer is a single crystalline silicon layer. 
     
     
       14. The method of  claim 12  wherein said light source is a semiconductor light emitter. 
     
     
       15. The method of  claim 14  wherein said semiconductor light emitter is a VCSEL chip. 
     
     
       16. The method of  claim 14  wherein said semiconductor light emitter is mounted using solder bumps. 
     
     
       17. The method of  claim 12  wherein said torsional mirror is actuated by a pair of electrodes. 
     
     
       18. The method of  claim 12  wherein said torsional mirror is actuated by a thin film coil and an external magnetic field. 
     
     
       19. The method of  claim 12  wherein a ferromagnetic thin film coil is attached to said torsional mirror. 
     
     
       20. The method of  claim 12  wherein a thin film coil is attached to said torsional mirror. 
     
     
       21. A MEMS formation method including: 
       
         providing a single crystal silicon layer;  
       
       
         forming at least one first MEMS component by patterning the single crystal silicon layer;  
       
       
         depositing at least one layer of polysilicon on the patterned single crystal silicon; and  
       
       
         forming at least one second MEMS component by patterning the polysilicon. 
       
     
     
       22. The method of  claim 21  wherein the single crystal silicon layer is bonded to an insulator layer in a SOI wafer and providing a single crystal silicon layer comprises providing a SOI wafer. 
     
     
       23. The method of  claim 21  wherein the at least one second MEMS component is a hinge. 
     
     
       24. The method of  claim 23  wherein the at least one first MEMS component is a mirror retained by the hinge. 
     
     
       25. The method of  claim 21  wherein depositing at least one layer of polysilicon includes chemical vapor deposition. 
     
     
       26. The method of  claim 21  wherein forming at least one first MEMS component includes forming a deflecting mirror. 
     
     
       27. A MEMS formation method including: 
       
         providing a single crystal silicon layer;  
       
       
         forming at least one first MEMS component by patterning the single crystal silicon layer;  
       
       
         depositing at least one layer of polysilicon on the patterned single crystal silicon; and  
       
       
         forming at least one second MEMS component by patterning the polysilicon, the at least one second MEMS component including a hinge retaining a deflecting mirror. 
       
     
     
       28. The method of  claim 27  wherein forming at least one first MEMS component further includes forming a torsional mirror, and the method further comprises forming a recess in the single crystal silicon layer and directing a light beam through the recess at the deflecting mirror so that the deflecting mirror deflects light to the torsional mirror. 
     
     
       29. A MEMS device comprising: 
       
         at least one single crystal silicon component; and  
       
       
         a hinge derived from a layer of polysilicon applied over the at least one single crystal silicon component. 
       
     
     
       30. The MEMS device of  claim 29  wherein the at least one single crystal silicon component is bonded to an insulator that rests on a handle wafer as a result of being formed from a single crystal silicon layer of a SOI wafer. 
     
     
       31. The MEMS device of  claim 29  wherein the at least one single crystal silicon component comprises a deflecting mirror. 
     
     
       32. The MEMS device of  claim 31  wherein the hinge retains the deflecting mirror. 
     
     
       33. The MEMS device of  claim 29  wherein the at least one single crystal silicon component comprises a torsional mirror. 
     
     
       34. A MEMS device comprising: 
       
         at least one single crystal silicon component;  
       
       
         at least one polysilicon component derived from a layer of polysilicon applied over the at least one single crystalline silicon component; and  
       
       
         a semiconductor light emitter mounted on a substrate bonded to a supporting structure of the at least one single crystal silicon component and oriented to emit a light beam at the at least one single crystal silicon component. 
       
     
     
       35. The MEMS device of  claim 34  wherein the at least one single crystal silicon component is bonded to an insulator as a result of having been formed from a single crystal silicon layer of an SOI wafer to which the semiconductor light emitter substrate is bonded. 
     
     
       36. The MEMS device of  claim 35  wherein the SOI wafer includes a recess into which the semiconductor light emitter projects. 
     
     
       37. The MEMS device of  claim 34  wherein the at least one single crystal silicon component comprises a deflecting mirror at which the light beam is directed and a torsional mirror to which the deflecting mirror deflects the light beam, and the at least one polysilicon component comprises a hinge retaining the deflecting mirror.