Embedded microelectromechanical systems (MEMS) semiconductor substrate and related method of forming

Abstract

An embedded MEMS semiconductor substrate is set forth and can be a starting material for subsequent semiconductor device processing. A MEMS device is formed in a semiconductor substrate, including at least one MEMS electrode and a buried silicon dioxide sacrificial layer has been applied for releasing the MEMS. A planarizing layer is applied over the substrate, MEMS device and MEMS electrode. A polysilicon protection layer is applied over the planarizing layer. A silicon nitride capping layer is applied over the polysilicon protection layer. A polsilicon seed layer is applied over the polysilicon nitride capping layer. The MEMS device is released by removing at least a portion of the buried silicon dioxide sacrificial layer and an epitaxial layer is grown over the polysilicon seed layer to be used for subsequent semiconductor wafer processing.

That which is claimed is: 
     
       1. A method of forming an embedded MEMS semiconductor substrate used as a starting material for subsequent semiconductor device processing, comprising:
 forming a MEMS device in a semiconductor substrate that includes at least one MEMS electrode and a buried silicon dioxide sacrificial layer used for releasing the MEMS; 
 applying a planarizing layer over the substrate, MEMS device and MEMS electrode; 
 applying a polysilicon protection layer over the planarizing layer; 
 applying a silicon nitride capping layer over the polysilicon protection layer; 
 applying a polysilicon seed layer over the silicon nitride capping layer; 
 releasing the MEMS device by removing at least a portion of the buried silicon dioxide sacrificial layer; and 
 growing an epitaxial layer over the polysilicon seed layer to be used for subsequent semiconductor wafer processing. 
 
     
     
       2. The method according to  claim 1 , wherein the subsequent semiconductor wafer processing comprises one of CMOS, BiCMOS, BCD and NV memory processing. 
     
     
       3. The method according to  claim 1 , which further comprises removing the buried oxide sacrificial layer using hydrofluoric acid releasing. 
     
     
       4. The method according to  claim 1 , which further comprises removing the planarizing layer by etching. 
     
     
       5. The method according to  claim 1 , which further comprises forming the planarizing layer as a TEOS and spin-on-glass layer. 
     
     
       6. The method according to  claim 1 , which further comprises forming the capping layer us a silicon nitride insulating layer. 
     
     
       7. The method according to  claim 1 , which further comprises forming the MEMS device as a resonator. 
     
     
       8. The method according to  claim 1 , which further comprises forming an electrode anchor supporting the at least one MEMS electrode. 
     
     
       9. The method according to  claim 8 , which further comprises forming an anchor to isolate the MEMS device. 
     
     
       10. The method according to  claim 1 , which further comprises forming vias within the protection, nitride capping and seed layers for use in subsequent releasing of the MEMS device and implanting MEMS device and MEMS electrode contacts. 
     
     
       11. The method according to  claim 1 , which further comprises isolating any MEMS device and MEMS electrode contacts using trench isolation. 
     
     
       12. The method according to  claim 1 , which further comprises removing the planarizing layer before growing an epitaxial layer. 
     
     
       13. A method of forming an embedded MEMS semiconductor substrate used as a starting material for subsequent semiconductor device processing, comprising:
 forming a MEMS device in a semiconductor substrate and at least one MEMS electrode and which includes a buried silicon dioxide sacrificial layer; 
 releasing the MEMS device by removing the buried sacrificial layer and applying a polysilicon seed layer and capping layer over the MEMS device and at least one MEMS electrode while also forming vias using photolithography and implanting deep contacts to the MEMS device and any MEMS electrodes and forming trench isolation of such deep contacts; and 
 growing an epitaxial layer over the polysilicon seed layer to be used for subsequent semiconductor wafer processing. 
 
     
     
       14. The method according to  claim 13 , wherein the subsequent semiconductor wafer processing comprises one of CMOS, BiCMOS, BCD and NV memory processing. 
     
     
       15. The method according to  claim 14 , and further comprising the step of applying planarizing and capping layers over the substrate, MEMS device and MEMS electrode before releasing the MEMS device. 
     
     
       16. The method according to  claim 15 , which further comprises forming the planarizing layer as a TEOS and spin-on-glass layer. 
     
     
       17. The method according to  claim 13 , which further comprises removing the buried oxide sacrificial layer using hydrofluoric acid releasing. 
     
     
       18. The method according to  claim 13 , which further comprises forming the MEMS device as a resonator. 
     
     
       19. The method according to  claim 13 , which further comprises isolating any MEMS device and MEMS electrode contacts using trench isolation. 
     
     
       20. A method of forming an embedded MEMS semiconductor substrate to be used as a starting material for subsequent semiconductor device processing, comprising:
 forming a MEMS device in a semiconductor substrate that includes at least one MEMS electrode and a buried sacrificial layer;   forming a planarizing layer over the semiconductor substrate and the MEMS device;   forming a protection layer over the planarizing layer;   forming a capping layer over the protection layer;   forming a seed layer over the capping layer;   releasing the at least one MEMS electrode by removing at least a portion of the buried sacrificial layer; and   growing a semiconductor layer over the seed layer to be used for subsequent semiconductor device processing.   
     
     
       21. The method according to claim 20, wherein the subsequent semiconductor device processing comprises one of CMOS, BiCMOS, BCD and NV memory processing. 
     
     
       22. The method according to claim 20, which further comprises removing the buried sacrificial layer using hydrofluoric acid releasing. 
     
     
       23. The method according to claim 20, which further comprises removing the planarizing layer by etching. 
     
     
       24. The method according to claim 20, which further comprises forming the planarizing layer as a TEOS and spin-on-glass layer. 
     
     
       25. The method according to claim 20, which further comprises forming the capping layer as a silicon nitride insulating layer. 
     
     
       26. The method according to claim 20, which further comprises forming the MEMS device as a resonator. 
     
     
       27. The method according to claim 20, which further comprises forming an electrode anchor supporting the at least one MEMS electrode. 
     
     
       28. The method according to claim 27, which further comprises forming an anchor to isolate the MEMS device. 
     
     
       29. The method according to claim 20, which further comprises forming vias within the protection, capping and seed layers for use in subsequent releasing of the at least one MEMS electrode and implanting MEMS device and MEMS electrode contacts. 
     
     
       30. The method according to claim 29, which further comprises isolating the MEMS device and MEMS electrode contacts using trench isolation. 
     
     
       31. The method according to claim 20, which further comprises removing the planarizing layer before growing a semiconductor layer. 
     
     
       32. A method of forming an embedded MEMS semiconductor substrate to be used as a starting material for subsequent semiconductor device processing, comprising:
 forming a MEMS device in a semiconductor substrate that includes at least one MEMS electrode and a buried sacrificial layer;   releasing the at least one MEMS electrode by removing the buried sacrificial layer and applying a seed layer and capping layer over the MEMS device and at least one MEMS electrode;   forming trench isolated contacts to the MEMS device and any MEMS electrode; and   growing a semiconductor layer over the seed layer to be used for subsequent semiconductor device processing.   
     
     
       33. The method according to claim 32, wherein the subsequent semiconductor device processing comprises one of CMOS, BiCMOS, BCD and NV memory processing. 
     
     
       34. The method according to claim 33, and further comprising the step of applying planarizing and capping layers over the semiconductor substrate, MEMS device and at least one MEMS electrode before releasing the MEMS device. 
     
     
       35. The method according to claim 33, which further comprises forming the planarizing layer as a TEOS and spin-on-glass layer. 
     
     
       36. The method according to claim 32, which further comprises removing the buried sacrificial layer using hydrofluoric acid releasing. 
     
     
       37. The method according to claim 32, which further comprises forming the MEMS device as a resonator.