What is claimed is:
1. A method of removing Group VIII metal-containing material from a surface of a substrate, the method comprising contacting the Group VIII metal-containing material with an acidic composition comprising phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid.
2. The method of claim 1 wherein the substrate is a semiconductor substrate or substrate assembly.
3. The method of claim 2 wherein the semiconductor substrate or substrate assembly is a wafer.
4. The method of claim 1 wherein the phosphoric acid is present in the composition initially in an amount of at least about 10 vol-% and no greater than about 25 vol-%.
5. The method of claim 1 wherein the sulfuric acid is present in the composition initially in an amount of at least about 10 vol-% and no greater than about 50 vol-%.
6. The method of claim 1 wherein the nitric acid is present in the composition initially in an amount of at least about 0.25 vol-% and no greater than about 10 vol-%.
7. The method of claim 6 wherein the nitric acid is present in the composition initially in an amount of at least about 0.25 vol-% and no greater than about 1 vol-%.
8. The method of claim 1 wherein the hydrochloric acid is present in the composition initially in an amount of at least about 25 vol-% and no greater than about 50 vol-%.
9. The method of claim 1 wherein the Group VIII metal-containing surface of the substrate comprises platinum in elemental form or an alloy thereof with one or more other Group VIII metals.
10. The method of claim 9 wherein the Group VIII metal-containing surface comprises a platinum alloy.
11. The method of claim 9 wherein the Group VIII metal-containing surface comprises elemental platinum or a platinumrhodium alloy.
12. The method of claim 11 wherein the Group VIII metal-containing surface comprises a platinumrhodium alloy comprising at least about 60 atomic percent platinum and no greater than about 40 atomic percent rhodium.
13. The method of claim 1 wherein contacting the Group VIII metal-containing material with an acidic composition comprises contacting the Group VIII metal-containing material with the acidic composition at a temperature of at least about 65 C.
14. The method of claim 11 wherein contacting the Group VIII metal-containing material with an acidic composition comprises immersing the substrate in the acidic composition.
15. The method of claim 11 wherein contacting the Group VIII metal-containing material with an acidic composition comprises spraying the substrate with the acidic composition.
16. The method of claim 1 wherein contacting the Group VIII metal-containing material with an acidic composition comprises:
positioning the Group VIII metal-containing surface of the substrate to interface with a polishing pad;
supplying an acidic composition in proximity to the interface; and
planarizing the substrate surface.
17. The method of claim 16 wherein the acidic composition comprises a plurality of abrasive particles.
18. The method of claim 16 wherein the polishing pad comprises a plurality of abrasive particles.
19. A method of removing Group VIII metal-containing material from a surface of a substrate, the method comprising contacting the Group VIII metal-containing material with an acidic composition comprising phosphoric acid initially in an amount of at least about 10 vol-% and no greater than about 25 vol-%, sulfuric acid initially in an amount of at least about 10 vol-% and no greater than about 50 vol-%, nitric acid initially in an amount of at least about 0.25 vol-% and no greater than about 10 vol-%, and hydrochloric acid initially in an amount of at least about 25 vol-% and no greater than about 50 vol-%.
20. The method of claim 19 wherein the substrate is a semiconductor substrate or substrate assembly.
21. The method of claim 19 wherein the Group VIII metal-containing surface comprises elemental platinum or a platinumrhodium alloy.
22. The method of claim 19 wherein contacting the Group VIII metal-containing material with an acidic composition comprises contacting the Group VIII metal-containing material with the acidic composition at a temperature of at least about 65 C.
23. The method of claim 19 wherein contacting the Group VIII metal-containing material with an acidic composition comprises immersing the substrate in the acidic composition.
24. The method of claim 19 wherein contacting the Group VIII metal-containing material with an acidic composition comprises spraying the substrate with the acidic composition.
25. The method of claim 19 wherein contacting the Group VIII metal-containing material with an acidic composition comprises:
positioning the Group VIII metal-containing surface of the substrate to interface with a polishing pad;
supplying an acidic composition in proximity to the interface; and
planarizing the substrate surface.
26. The method of claim 25 wherein the acidic composition comprises a plurality of abrasive particles.
27. The method of claim 25 wherein the polishing pad comprises a plurality of abrasive particles.
28. A method of removing platinum-rhodium alloy from a surface of a substrate, the method comprising contacting the platinum-rhodium alloy-containing material with an acidic composition comprising phosphoric acid initially in an amount of at least about 10 vol-% and no greater than about 25 vol-%, sulfuric acid initially in an amount of at least about 10 vol-% and no greater than about 50 vol-%, nitric acid initially in an amount of at least about 0.25 vol-% and no greater than about 1 vol-%, and hydrochloric acid initially in an amount of at least about 25 vol-% and no greater than about 50 vol-%.
29. An acidic composition for removing a Group VIII metal-containing material from a surface of a substrate, the composition comprising:
phosphoric acid initially in an amount of at least about 10 vol-% and no greater than about 25 vol-%;
sulfuric acid initially in an amount of at least about 10 vol-% and no greater than about 50 vol-%;
nitric acid initially in an amount of at least about 0.25 vol-% and no greater than about 10 vol-%; and
hydrochloric acid initially in an amount of at least about 25 vol-% and no greater than about 50 vol-%.
30. The acidic composition of claim 29 wherein nitric acid is initially present in an amount of at least about 0.25 vol-% and no greater than about 1 vol-%.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A sigma-delta modulator (SDM), comprising:
an integrator for integrating an SDM error signal to provide an SDM output;
an overload protection circuit to detect an overload condition of said integrator, and, if an overload condition is detected, to apply a feedback signal to increase a reference voltage of said SDM to keep a residual error within predetermined limits; and
a circuit to digitally combine said feedback signal with the SDM output, whereby said SDM is kept out of the overload condition.
2. The SDM of claim 1 further comprising:
a first summing junction configured to receive a modulator input signal and a system feedback signal, and to generate a system error signal by combining the input signal and the system feedback signal;
an amplifier for providing an amplified system feedback signal to the first summing junction;
and wherein said overload protection circuit comprises:
an overload sensor circuit to monitor an output of one of said feedback loops for an overload condition; and
an overload feedback protection circuit to product a feedback signal to said first summing junction if an overload condition is detected by said overload sensor circuit, thereby increasing a reference voltage of said SDM.
3. A method for providing signal overload protection in a sigma-delta modulator (SDM) comprising:
integrating an SDM error signal to provide an SDM output;
detecting on overload condition of said integrator;
if an overload condition is detected applying a feedback signal to effectively increase a reference voltage of said SDM to keep a residual error within predetermined limits; and
digitally combining said feedback signal with the SDM output to keep said SDM out of the overload condition.
4. The method of claim 3 where said effectively increasing said reference voltage of said SDM comprises subtracting said feedback signal from an SDM input signal.