초록 ▼

According to one aspect of the disclosure, laser-thermal annealing is used to clear an imaging path through the back side of a semiconductor device after the back side of the chip has been thinned to expose a selected region in the substrate. For many applications, thinning results in the formation

According to one aspect of the disclosure, laser-thermal annealing is used to clear an imaging path through the back side of a semiconductor device after the back side of the chip has been thinned to expose a selected region in the substrate. For many applications, thinning results in the formation of crystal defects that inhibit the ability to obtain images through the back side of the semiconductor device. One example embodiment overcomes this problem by thinning via laser-chemical etching the back side of the semiconductor device under a pressure exceeding a threshold level, and then reducing the pressure to a level below the threshold level and scanning the back side of the semiconductor device using a laser at a reduced power level. IR microscopy is then used to capture an image of a circuit in the circuit side of the semiconductor device through the back side of the semiconductor device. One particular example application is directed to a flip-chip semiconductor device. Another aspect of the invention is directed to clearing collision-induced viewing impairments, as may be caused by plasma etching.

대표청구항 ▼

According to one aspect of the disclosure, laser-thermal annealing is used to clear an imaging path through the back side of a semiconductor device after the back side of the chip has been thinned to expose a selected region in the substrate. For many applications, thinning results in the formation

According to one aspect of the disclosure, laser-thermal annealing is used to clear an imaging path through the back side of a semiconductor device after the back side of the chip has been thinned to expose a selected region in the substrate. For many applications, thinning results in the formation of crystal defects that inhibit the ability to obtain images through the back side of the semiconductor device. One example embodiment overcomes this problem by thinning via laser-chemical etching the back side of the semiconductor device under a pressure exceeding a threshold level, and then reducing the pressure to a level below the threshold level and scanning the back side of the semiconductor device using a laser at a reduced power level. IR microscopy is then used to capture an image of a circuit in the circuit side of the semiconductor device through the back side of the semiconductor device. One particular example application is directed to a flip-chip semiconductor device. Another aspect of the invention is directed to clearing collision-induced viewing impairments, as may be caused by plasma etching. shing the front and back surfaces of the wafer. 4. A method as set forth in claim 3 wherein the final polishing operation removes material simultaneously from both surfaces of the wafer. 5. A method as set forth in claim 3 wherein the final polishing operation removes between about 0.1 and 1.5 microns of wafer material. 6. A method as set forth in claim 3 wherein the method is free of any material removal operation between said simultaneous rough polishing operation and said final polishing operation other than cleaning the wafer. 7. A method as set forth in claim 3 wherein the rough polishing operation produces a substantially mirror finish on at least the front surface, the rough polishing operation being performed in a first polishing apparatus and the final polishing operation is performed in a second polishing apparatus, both apparatus being adapted to simultaneously batch process multiple wafers. 8. A method as set forth in claim 3 wherein the method is free of an operation for forming a layer on the wafer. 9. A method as set forth in claim 3 wherein the method is free of a single surface polishing operation wherein the back surface is substantially fixed against a backing surface. 10. A method as set forth in claim 3 wherein the wafer is packaged after said final polishing operation. 11. A method as set forth in claim 1 wherein the final polishing operation further comprises: (a) providing a polishing apparatus having a wafer carrier generally disposed between the first pad and the second pad, b) placing said wafer in the water carrier so that said front surface faces said first pad and so that said back surface faces said second pad, the wafer being free to move relative to the first and second pads, (c) applying a polishing slurry to said pads, (d) rotating at least one of the carrier, first pad and second pad for polishing at least said front surface of said wafer. 12. A method as set forth in claim 11 wherein the operation of providing a polishing apparatus includes providing the polishing apparatus free of composite reinforcing particles in contact with the wafer, the pads or the polishing slurry so as to inhibit particle contact with the wafer. 13. A method as set forth in claim 11 wherein the operation of providing a polishing apparatus includes providing the polishing apparatus including carrier drive components adapted to be in contact with the polishing slurry, the drive components and wafer carriers having substantially no fiberglass therein so that fiberglass particle contact with the wafer is inhibited. 14. A method as set forth in claim 11 wherein the final polishing operation removes between about 0.1 and 1.5 microns of wafer material. 15. A method as set forth in claim 11 wherein the final polishing operation removes significantly less water material from the back surface than the front surface. 16. A method as set forth in claim 11 further comprising the step of applying a rinsing fluid between the pads after polishing is substantially complete so that a resulting solution including the slurry and the rinsing fluid is alkaline. 17. A method as set forth in claim 11 further comprising the step of applying a rinsing fluid between the pads after polishing is substantially complete so that a resulting solution including the slurry and the rinsing fluid has a buffered pH between about 7.8 and about 11.8. 18. A method as set forth in claim 11 further comprising the operation of applying pressure to the first and second pads and thereby to the wafer, wherein the operation of providing a polishing apparatus includes providing the second pad having a significantly larger size than the wafer, the back surface of the water mounted to be translatable and rotatable relative to the second pad, wherein the rotating step includes rotating and moving the wafer such that substantially all of the back surface of the wafer is substantially continuously moving relative to the second pad so that deviations in the sec