All The Claims

1. A level shifter, comprising:
an input voltage supply node and an input reference node operative within a first power domain;
an output voltage supply node and an output reference node operative within a second power domain;
an input signal node for receiving an input signal operable within said first power domain;
an output signal node;
a level shifter network which is configured to receive said input signal at said input signal node, to perform voltage shifting between said input voltage supply node and said output voltage supply node and between said input reference node and said output reference node, and to provide an output signal via said output signal node, wherein said output signal represents said input signal and is operable within said second power domain; and
wherein said level shifter circuit further comprises a ground bypass input for receiving a ground bypass signal, and wherein said level shifter circuit bypasses at least a portion of said level shifter circuit performing voltage shifting between said input reference node and said output reference node when said ground bypass signal indicates ground bypass.
2. The level shifter of claim 1, wherein said level shifter network further comprises a voltage supply bypass input configured to receive a voltage supply bypass signal, and wherein said level shifter network bypasses at least a portion of the level network performing voltage shifting between said input voltage supply node and said output voltage supply node when said voltage supply bypass signal indicates voltage supply bypass.
3. The level shifter of claim 1, wherein said level shifter network further comprises an isolation input configured to receive an isolation signal, and wherein said level shifter network drives said output node to one of said output voltage supply node and said output reference node when said isolation signal indicates isolation.
4. The level shifter of claim 1, wherein said level shifter network comprises:
a reference level shifter which receives said input signal and which provides a corresponding intermediate signal operable between said input voltage supply node and said output reference node; and
a power level shifter which receives said intermediate signal and which provides said output signal operable between said output voltage supply node and said output reference node.
5. The level shifter of claim 4, wherein said reference level shifter comprises:
a first inverter coupled between said input voltage supply node and said input reference node having an input receiving said input signal and an output providing an inverted input signal operative within said first power domain;
a second inverter coupled between said input voltage supply node and a first node, said second inverter having an input receiving said input signal and an output coupled to a first intermediate node;
a third inverter coupled between said input voltage supply node and a second node, said third inverter having an input receiving said inverted input signal and an output coupled to a second intermediate node;
a first level shift device having a current path coupled between said first node and said output reference node and having a control input coupled to said second intermediate node; and
a second level shift device having a current path coupled between said second node and said output reference node and having a control input coupled to said first intermediate node.
6. The level shifter of claim 5, wherein said first, second and third inverters each comprise complementary metal-oxide semiconductor inverters and wherein said first and second level shift devices each comprise an N-channel metal-oxide semiconductor device.
7. The level shifter of claim 5, further comprising a bypass circuit which, when asserted for ground voltage shifting bypass, couples said first node to said output reference node and decouples said first level shift device from said output reference node.
8. The level shifter of claim 4, wherein said reference level shifter provides said intermediate signal and an inverted intermediate signal, and wherein said power level shifter comprises:
a first inverter coupled between said output reference node and a first node, said first inverter having an input receiving said inverted intermediate signal and an output coupled to an intermediate output node;
a second inverter coupled between said output reference node and a second node, said second inverter having an input receiving said intermediate signal and an output coupled to a third node;
a first level shift device having a current path coupled between said first node and said output voltage supply node and having a control input coupled to said third node;
a second level shift device having a current path coupled between said second node and said output voltage supply node and having a control input coupled to said intermediate output node; and
a buffer having an input coupled to said intermediate output node and an output coupled to said output signal node providing said output signal.
9. The level shifter of claim 8, wherein said first and second inverters each comprise complementary metal-oxide semiconductor inverters and wherein said first and second level shift devices each comprise a P-channel metal-oxide semiconductor device.
10. The level shifter of claim 8, further comprising a bypass circuit which, when asserted for power shifting bypass, couples said first node to said output voltage supply node.
11. The level shifter of claim 8, further comprising an isolation circuit which, when asserted for isolation, drives said intermediate output node to one of said output voltage supply node and said output reference node.
12. A method of voltage level shifting a binary signal between independent voltage domains, comprising:
receiving an input binary signal operative within a first power domain, wherein the input binary signal switches between a first reference voltage and a first source voltage;
level shifting the input binary signal to an output binary signal operative within a second power domain, wherein the output binary signal switches between a second reference voltage and a second source voltage, and wherein the second reference voltage is different from the first reference voltage and the second source voltage is different from the first source voltage;
receiving a reference bypass signal indicating that the first and second reference voltages are at a common voltage level; and
bypassing said level shifting between the first and second reference voltages when the bypass signal indicates that the first and second reference voltages are at a common voltage level.
13. The method of claim 12, wherein said level shifting comprises:
level shifting the first reference voltage of the input binary signal to the second reference voltage and providing an intermediate binary signal which switches between the second reference voltage and the first source voltage; and
level shifting the first source voltage of the intermediate signal to the second source voltage and providing the output binary signal which switches between the second reference voltage and the second source voltage of the second power domain.
14. The method of claim 12, further comprising:
receiving a voltage supply bypass signal indicatin that the first and second source voltages are at a common voltage level; and
bypassing said level shifting between the first and second source voltages when the voltage supply bypass signal indicates that the first and second source voltages are at a common voltage level.
15. The method of claim 12, further comprising:
receiving an isolation signal indicating a lower power state; and
asserting the output binary signal to one of the second reference voltage and the second source voltage during the low power state.
16. A level shifter, comprising:
an input voltage supply node and an input reference node operative within a first power domain;
an output voltage supply node and an output reference node operative within a second power domain;
an input signal node for receiving an input signal operable within said first power domain;
an output signal node;
a level shifter circuit which is configured to receive said input signal at said input signal node, to perform voltage shifting between said input voltage supply node and said output voltage supply node and between said input reference node and said output reference node, and to provide an output signal via said output signal node, wherein said output signal represents said input signal and is operable within said second power domain; and
wherein said level shifter circuit further comprises a voltage supply bypass input for receiving a voltage supply bypass signal, and wherein said level shifter circuit bypasses at least a portion of said level shifter circuit performing voltage shifting between said input voltage supply node and said output voltage supply node when said voltage supply bypass signal indicates voltage supply bypass.
17. The level shifter of claim 16, wherein said level shifter circuit further comprises an isolation input configured to receive an isolation signal, and wherein said level shifter circuit drives said output node to one of said output voltage supply node and said output reference node when said isolation signal indicates isolation.
18. A method of voltage level shifting a binary signal between independent voltage domains, comprising:
receiving an input binary signal operative within a first power domain, wherein the input binary signal switches between a first reference voltage and a first source voltage;
level shifting the input binary signal to an output binary signal operative within a second power domain, wherein the output binary signal switches between a second reference voltage and a second source voltage, and wherein the second reference voltage is different from the first reference voltage and the second source voltage is different from the first source voltage;
receiving a source bypass signal indicating that the first and second source voltages are at a common voltage level; and
bypassing said level shifting between the first and second source voltages when the bypass signal indicates that the first and second source voltages are at a common voltage level.
19. The method of claim 18, further comprising:
receiving an isolation signal indicating a lower power state; and
asserting the output binary signal to one of the second reference voltage and the second source voltage during the low power state.

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 semiconductor device, comprising:
a plurality of lines disposed on a semiconductor substrate; and
remaining line patterns disposed spaced apart from the lines on extensions from the lines,
wherein the lines include first end-portions adjacent to the remaining line patterns,
the remaining line patterns include second end-portions adjacent to the lines, and
the first end-portions and second end-portions are formed to have mirror symmetry with respect to each other.
2. The semiconductor device as claimed in claim 1, wherein each of the first end-portions has a width greater than the lines.
3. The semiconductor device as claimed in claim 1, wherein a sidewall slope of the first end-portions is more gentle than a sidewall slope of the lines.
4. The semiconductor device as claimed in claim 1, further comprising a device isolation layer disposed on the substrate to define a dummy active region and a cell active region,
wherein the dummy active region is between the first end-portions and the second end-portions.
5. The semiconductor device as claimed in claim 4, wherein a width of the dummy active region is greater than that of the cell active region.
6. The semiconductor device as claimed in claim 4, further comprising:
dummy floating gates disposed between the lines and the dummy active region; and
cell floating gates disposed between the lines and the cell active region.
7. The semiconductor device as claimed in claim 6, wherein:
at least some of adjacent ones of the dummy floating gates are in contact with each other, and
all of the cell floating gates are spaced apart from each other.
8. The semiconductor device as claimed in claim 1, wherein the remaining line patterns are spaced apart from each other.
9. The semiconductor device as claimed in claim 8, wherein:
the remaining line patterns further include third end-portions spaced apart from the second end-portions, and
widths of the second and third end-portions are greater than widths of the lines.
10. The semiconductor device of claim 1, wherein at least portions of the remaining line patterns are connected to each other.
11.-20. (canceled)

1. A method of forming a silicon oxide layer on a semiconductor substrate comprising:
spin coating the semiconductor substrate with a SOG composition to form a SOG coating, the SOG composition including polysilazane dissolved in a first solvent;
heating the SOG coating to a temperature of not more than about 400\xb0 C. for a soft bake time sufficient to evaporate substantially all of the first solvent from the SOG coating and thereby form a SOG layer; and
treating the SOG layer with an oxidant solution selected from a group consisting of:
an aqueous ozone solution, the concentration of ozone being between about 1 ppm and about 200 ppm, and an aqueous solution of hydrogen peroxide, the concentration of hydrogen peroxide being between about 0.5 weight percent and about 30 weight percent, to convert the polysilazane to silicon oxide.
2. A method of forming a silicon oxide layer according to claim 1, wherein the oxidant solution further comprises:
at least one secondary oxidant selected from a group consisting of permanganates, hypochlorites, chlorites, chlorates, perchlorates, hypobromites, bromites, bromates, hypoiodites, iodites, iodates, nitric acid and sulfuric acid.
3. A method of forming a silicon oxide layer according to claim 1, wherein treating the SOG layer further comprises:
applying the oxidant solution to the SOG layer by dipping, spraying or puddling, the oxidant solution including an oxidant dissolved in a second solvent.
4. A method of forming a silicon oxide layer according to claim 1, wherein the oxidant solution further comprises:
an aqueous ozone solution, the concentration of ozone being between about 5 ppm and about 100 ppm, the oxidant solution being applied to the SOG layer at a temperature of between about 20\xb0 C. and about 40\xb0 C.
5. A method of forming a silicon oxide layer according to claim 1, wherein forming the SOG layer further comprises:
further heating the SOG layer to a temperature between about 300\xb0 C. to about 500\xb0 C. under an oxidizing atmosphere for a time period between about 10 and about 120 minutes to form a partially converted SOG layer including silicon dioxide and polysilazane; and
treating the partially converted SOG layer with the oxidant solution to covert substantially all remaining polysilazane into silicon dioxide and thereby form the silicon dioxide layer.
6. A method of forming a silicon oxide layer according to claim 1, wherein the oxidant solution further comprises:
an aqueous solution of hydrogen peroxide, the oxidant solution being applied to the SOG layer at a temperature of between about 25\xb0 C. and about 90\xb0 C.
7. A method of forming a silicon oxide layer according to claim 6, wherein the oxidant solution further comprises:
an aqueous solution of ammonium hydroxide and hydrogen peroxide, the relative concentration of the ammonium hydroxide and hydrogen peroxide being sufficient to establish an ammonium hydroxide: hydrogen peroxide weight ratio between about 1:3 and 1:10.
8. A method of forming a silicon oxide layer according to claim 7, wherein the oxidant solution further comprises:
an aqueous solution of hydrogen peroxide and ammonium hydroxide, the concentration of hydrogen peroxide being between about 3 weight percent and about 10 weight percent and the concentration of the ammonium hydroxide being between about 0.5 weight percent and about 5 weight percent, the oxidant solution being applied to the SOG layer at a temperature of between about 40\xb0 C. and about 80\xb0 C.
9. A method of forming a silicon oxide layer according to claim 1, wherein:
the first solvent is an organic solvent;
and further wherein:
the SOG composition includes between about 5 weight percent and about 30 weight percent polysilazane.
10. A method of forming a silicon oxide layer according to claim 9, wherein:
the first solvent is selected from a group of organic solvents consisting of aromatic solvents, aliphatic solvents and ether-type solvents;
and further wherein:
the first solvent is between about 70 weight percent and about 95 weight percent of the SOG composition.
11. A method of forming a silicon oxide layer according to claim 10, wherein:
the first solvent includes at least one selected from the group consisting of toluene, benzene, xylene, dibutylether, diethylether, THF, PGME, PGMEA and hexane.
12. A method of forming a silicon oxide layer according to claim 1, wherein forming the SOG layer further comprises:
further heating the SOG layer to a temperature between about 300\xb0 C. and about 600\xb0 C. for a hard bake time sufficient to density the SOG layer.
13. A method of forming a silicon oxide layer according to claim 12, wherein forming the SOG layer further comprises:
further heating the SOG layer to a temperature between about 300\xb0 C. and about 600\xb0 C. for a hard bake time sufficient to increase a HF etch resistance of the SOG layer by at least 50%.
14. A method of forming a silicon oxide layer according to claim 12, further comprising:
annealing the silicon oxide layer at a temperature of at least 600\xb0 C. for an anneal time sufficient to form a densified silicon oxide layer.
15. A method of forming a silicon oxide layer according to claim 14, further comprising:
planarizing the densified silicon oxide layer.
16. A method of forming a silicon oxide layer according to claim 15, wherein planarizing the densified silicon oxide layer further comprises:
removing an upper portion of the densified silicon oxide layer using a dry etch, a wet etch or a chemical mechanical planarization (CMP).
17. A method of forming a silicon oxide layer according to claim 15, wherein planarizing the densified silicon oxide layer further comprises:
removing an upper portion of the densified silicon oxide layer to expose an upper surface of the semiconductor substrate.
18. A method of forming a silicon oxide layer according to claim 15, wherein planarizing the densified silicon oxide layer further comprises:
removing an upper portion of the densified silicon oxide layer to expose an upper surface of the semiconductor substrate using a CMP process; and
etching the silicon oxide layer to produce an oxide surface that is recessed relative to the upper surface of the semiconductor substrate.
19. A method of forming a silicon oxide layer according to claim 1, wherein:
the semiconductor substrate includes a pattern.
20. A method of forming a silicon oxide layer according to claim 19, wherein:
the pattern includes a conductive material.
21. A method of forming a silicon oxide layer according to claim 20, wherein:
the conductive material includes tungsten (W) or tungsten silicide (WSix).
22. A method of forming a silicon oxide layer according to claim 20, wherein:
the conductive material includes aluminum or copper.
23. A method of forming a silicon oxide layer according to claim 19, wherein:
the pattern includes recesses formed in the semiconductor substrate.
24. A method of forming a silicon oxide layer according to claim 23, wherein:
the pattern includes shallow trench isolation (STI) openings formed in the conductor substrate.
25. A method of manufacturing a semiconductor device comprising:
forming a SOG layer on a semiconductor substrate, the SOG layer including a polysilazane; and
treating the SOG layer with an oxidant solution selected from a group consisting of an aqueous ozone solution, the concentration of ozone being between about 1 ppm and about 200 ppm, and an aqueous hydrogen peroxide solution, the concentration of hydrogen peroxide being between about 0.5 weight percent and about 30 weight percent, to convert the polysilazane to silicon oxide.
26. A method of manufacturing a semiconductor device according to claim 25, further comprising:
forming isolation trench structures on the semiconductor substrate;
filling the isolation trench structures with the SOG layer; and
removing an upper portion of the silicon oxide to expose a surface of the semiconductor substrate.
27. A method of manufacturing a semiconductor device according to claim 25, further comprising:
forming gate electrode structures on the semiconductor substrate;
covering the gate electrode structures with the SOG layer;
forming openings in the silicon oxide to expose portions of the gate electrode structures; and
depositing a first metal layer on the silicon oxide.
28. A method of manufacturing a semiconductor device according to claim 25, further comprising:
forming a first conductive pattern on the semiconductor substrate;
covering the first conductive pattern with the SOG layer;
forming openings in the silicon oxide to expose portions of the first conductive pattern; and
depositing a second conductive layer on the silicon oxide.
29. A method of manufacturing a semiconductor device according to claim 25, further comprising:
forming a pattern on the semiconductor substrate, the pattern including recessed portions;
covering the pattern and filling the recessed portions with the SOG layer; and
removing an upper portion of the silicon oxide to expose a surface of the semiconductor substrate.
30. A method of manufacturing a semiconductor device according to claim 29, further comprising:
removing an additional portion of the silicon oxide to form an oxide surface in the recessed portion, the oxide surface being recessed relative to the surface of the semiconductor substrate.
31. A method of manufacturing a semiconductor device according to claim 30, wherein:
removing an upper portion of the silicon oxide is achieved using an etchback process or a CMP process; and
removing the additional portion of the silicon oxide is achieved an etchback process.
32. A method of manufacturing a semiconductor device comprising:
forming isolation trench structures on the semiconductor substrate;
filling the isolation trench structures with a first SOG layer, the first SOG layer including a polysilazane;
treating the first SOG layer with a first oxidant solution to form a first silicon oxide layer;
removing an upper portion of the first silicon oxide layer to expose a surface of the semiconductor substrate;
forming gate electrode structures on the surface of the semiconductor substrate;
covering the gate electrode structures with a second SOG layer, the second SOG layer including a polysilazane;
treating the second SOG layer with a second oxidant solution to form a second silicon oxide layer;
forming contact openings in the second silicon oxide layer to expose portions of the gate electrode structures;
forming a first conductive pattern on the second silicon oxide layer;
covering the first conductive pattern with a third SOG layer, the third SOG layer including a polysilazane;
treating the third SOG layer with a third oxidant solution to form a third silicon oxide layer;
forming via openings in the third silicon oxide layer to expose portions of the first conductive pattern; and
forming a second conductive pattern on the third silicon oxide layer.
33. A method of manufacturing a semiconductor device according to claim 32, wherein:
each of the oxidant solutions includes at least one oxidant selected from a group consisting of ozone, peroxides, permanganates, hypochlorites, chlorites, chlorates, perchlorates, hypobromites, bromites, bromates, hypoiodites, iodites, iodates, nitric acid and sulfuric acid.
34. A method of forming a silicon oxide layer on a semiconductor substrate comprising:
forming a spin-on-glass (SOG) layer on the semiconductor substrate, the SOG layer including polysilazane;
baking the spin-on-glass layer to convert a first portion of the polysilazane to silicon oxide while retaining an unconverted second portion of the polysilazane; and
treating the SOG layer with an oxidant solution selected from a group consisting of an aqueous ozone solution, the concentration of ozone being between about 1 ppm and about 200 ppm, and an aqueous hydrogen peroxide solution, the concentration of hydrogen peroxide being between about 0.5 weight percent and about 30 weight percent, to convert the second portion of the polysilazane to silicon oxide, thereby forming the silicon oxide layer.
35. A method of forming a silicon oxide layer according to claim 34, wherein the oxidant solution further comprises:
at least one secondary oxidant selected from the group consisting of permanganates, hypochlorites, chlorites, chlorates, perchlorates, hypobromites, bromites, bromates, hypoiodites, iodites, iodates, nitric acid and sulfuric acid.
36. A method of forming a silicon oxide layer according to claim 34, wherein treating the SOG layer further comprises:
applying the oxidant solution to the SOG layer by dipping, spraying or puddling, the oxidant solution including an oxidant dissolved in a second solvent.
37. A method of forming a silicon oxide layer according to claim 34, wherein forming the SOG layer further comprises:
spin coating the semiconductor substrate with a SOG composition to form a SOG coating, the SOG composition including polysilazane dissolved in a first solvent; and
heating the SOG coating to a temperature of not more than about 400\xb0 C. for a time sufficient to evaporate substantially all of the first solvent from the SOG coating and thereby form the SOG layer.
38. A method of forming a silicon oxide layer according to claim 37, wherein:
the first solvent is an organic solvent;
and further wherein:
the SOG composition includes between about 5 weight percent and about 30 weight percent polysilazane.
39. A method of forming a silicon oxide layer according to claim 38, wherein:
the first solvent includes at least one selected from the group consisting of toluene, benzene, xylene, dibutylether, diethylether, THF, PGME, PGMEA and hexane.
40. A method of forming a silicon oxide layer according to claim 37, wherein:
the baking the spin-on-glass layer is conducted in an oxidizing atmosphere.
41. A method of forming a silicon oxide layer according to claim 40, wherein:
the oxidizing atmosphere is an oxygen atmosphere or a water-vapor atmosphere.
42. A method of forming a silicon oxide layer according to claim 41, further comprising:
annealing the silicon oxide layer at a temperature of at least 600\xb0 C. for a time sufficient to form a densified silicon oxide layer.
43. A method of forming a silicon oxide layer according to claim 42, further comprising:
planarizing the silicon oxide layer.
44. A method of forming a silicon oxide layer according to claim 34, wherein:
the semiconductor substrate includes a pattern.
45. A method of forming a silicon oxide layer according to claim 44, wherein:
the pattern includes recesses formed in the semiconductor substrate.
46. A method of forming a silicon oxide layer according to claim 44, wherein:
the pattern includes a conductive material.
47. A method of forming a silicon oxide layer according to claim 46, wherein:
the conductive material includes tungsten (W) or tungsten silicide (WSix).

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 snow thrower comprising:
an engine;
an auger housing configured to receive a snow;
an auger within the auger housing and operably coupled to the engine so as to be driven by the engine;
an impeller housing configured to receive snow driven by the auger from the auger housing;
a discharge chute extending from the impeller housing; and
an impeller within the impeller housing and operably coupled to the engine so as to be driven by the engine to discharge snow from the impeller housing through the discharge chute, the impeller comprising:
a layer of material having bent portions such that the layer of material comprises a plurality of shovels, each of the plurality of shovels comprising:
a blade support wall having a leading portion and a trailing portion; and
a blade having a base extending from the trailing portion of the blade support wall, wherein each of the blades has a snow driving face, the snow driving face of each blade facing in a direction about the rotation axis of the impeller, wherein the blade is independently upright with respect to the blade support wall so as to be connected to the impeller solely at the base of the blade to form an unobstructed snow receiving volume between a rear face of the shovel and the snow driving face of a trailing blade.
2. The snow thrower of claim 1, wherein each of the blades has an outermost radial tip with a blade edge, the blade edge having a first radially inward taper.
3. The snow thrower of claim 2, wherein each blade comprises an angled top having a radially outermost top edge, the top edge having a chamfer.
4. The snow thrower of claim 1, wherein each blade comprises an angled top having a radially outermost top edge, the top edge having a chamfer.
5. The snow thrower of claim 1, wherein each blade is configured to bend inwardly and rearwardly when encountering non-snow obstructions while rotating a speed of at least 1200 revolutions per minute.
6. The snow thrower of claim 1, wherein each of the blades has a recessed portion proximate an outermost tip of the blade, the recessed portion facing and recessed from a plane that contains the rotational axis of the impeller and that extends from the rotational axis tangent to the snow driving face.
7. The snow thrower of claim 6, wherein the recessed portion is concave.
8. The snow thrower of claim 6, wherein the recessed portion has a radius of curvature of between 16 inches and 22 inches.
9. The snow thrower of claim 6, wherein the snow driving face includes a convex portion between the recessed portion and the rotational axis of the impeller.
10. The snow thrower of claim 1, wherein each of the blades has a snow driving face, the snow driving face of each blade facing in a direction about the rotation axis of the impeller and wherein the impeller further comprises louvers extending through the blade support wall, each louver facing in the direction.
11. The snow thrower of claim 10 further comprising a web along the leading portion of the blade support wall, the web terminating at a notch extending from the web to an outer radial end of the blade support wall.
12. The snow thrower of claim 10, wherein each of the blades project from a first side of the blade support wall and wherein the louvers have fins projecting from a second side of the blade support wall opposite the first side.
13. The snow thrower of claim 1 further comprising a depression gusset in the snow driving face of each blade and extending from the blade to the blade support wall, each depression gusset having a maximum inside diameter of between 0.4 inches and 0.8 inches and a height measured perpendicularly from the blade support wall of between 1.5 inches and 1.9 inches.
14. The snow thrower of claim 1, wherein the impeller further comprises:
an aperture through the layer; and
a non-circular depression in the layer about the aperture;
wherein the snow thrower further comprises a shaft coupler comprising:
a hub received within the aperture and configured to mount to a shaft; and
key portions extending from the hub and received within the non-circular depression so as to key the hub to the impeller.
15. The snow thrower of claim 1, wherein each of the blades has a snow driving face and wherein the snow thrower further comprises a web extending and tapering from the snow driving face of each blade to a perimeter of the blade support wall.
16. The snow thrower of claim 15, wherein the web has a concave side facing away from the rotational axis of the impeller.
17. The snow thrower of claim 1, wherein each of the blades has a snow driving face and wherein each blade has a top portion extending oblique from the snow driving face.
18. The snow thrower of claim 1, wherein the blade support wall extends along a base of the snow driving face and projects in the direction from the snow driving face.
19. The snow thrower of claim 1, wherein the layer of material comprises three shovels spaced 120\xb0 about a rotational axis of the impeller with no other shovels between the three shovels, each shovel having a blade with a height measured perpendicularly from the blade support wall of at least 2.5 inches.
20. The snow thrower of claim 1 further comprising a second layer of material, the second layer of material having bent portions such that the second layer of material comprises a second plurality of shovels, each of the second plurality of shovels comprising:
a second blade support wall having a leading portion and a trailing portion; and
a second blade extending from the leading portion of the second blade support wall,
wherein the second layer overlies the first layer and is angularly offset from the first layer to form the impeller having at least four shovels.
21. The snow thrower of claim 20, wherein the first layer comprises a first shovel and a second shovel angularly spaced 180\xb0 from the first shovel, wherein the second layer comprises a third and a fourth shovel angularly spaced 180\xb0 from the third shovel, wherein the first shovel and the second shovel are angularly spaced from one another by 90\xb0.
22. The snow thrower of claim 20, wherein the first layer includes a noncircular raised portion and wherein the second layer includes a non-circular depression receiving the noncircular raised portion.
23. The snow thrower of claim 22, wherein the second layer further comprises:
a depression gusset extending between the second blade support wall and the second blade of each of the second plurality of shovels, wherein the noncircular depression comprises:
a first portion interconnecting the depression gusset of a first one of the second plurality of shovels and the depression gusset of a second one of the plurality of shovels; and
a second portion extending from the first portion perpendicular to the first portion.
24. The snow thrower of claim 1, wherein the layer of material comprises a 9 gauge low carbon steel.
25. The snow thrower of claim 1, wherein the layer of material comprises a 10 gauge low carbon steel.
26. The snow thrower of claim 1, wherein the layer of material comprises an 8 gauge low carbon steel.
27. The snow thrower of claim 10 further comprising a web along the leading portion of the blade support wall on a same side of the impeller as the snow driving face, the web extending from one of the blades and terminating opposite one of the louvers.
28. A snow thrower comprising:
an engine;
an auger housing configured to receive a snow;
an auger within the auger housing and operably coupled to the engine so as to be driven by the engine;
an impeller housing configured to receive snow driven by the auger from the auger housing;
a discharge chute extending from the impeller housing;
an impeller within the impeller housing and operably coupled to the engine so as to be driven by the engine to discharge snow from the impeller housing through the discharge chute, the impeller comprising:
a layer of material formed from cold rolled steel having a thickness of between 0.110 inches and 0.154 inches, the layer having bent portions such that the layer of material comprises a plurality of shovels, each of the plurality of shovels comprising:
a blade support wall having a leading portion and a trailing portion; and
a blade extending from the trailing leading portion of the blade support wall;
an aperture through the layer;
a non-circular depression in the layer about the aperture;
a depression gusset in the snow driving face of each blade and extending from the blade to the blade support wall; and
an intermediate depression channel in the layer of material connecting an interior of the depression gusset to an interior of the non-circular depression; and
a shaft coupler comprising:
a hub received within the aperture and configured to mount to a shaft; and
key portions extending from the hub and received within the non-circular depression so as to key the hub to the impeller.
29. The snow thrower of claim 28 further comprising an embossed rib in each blade and extending from the depression gusset towards a top of the blade, wherein the depression gusset forms a channel on a face of the blade opposite the snow driving face and wherein the embossed rib forms a channel on the snow driving face.
30. The Snow thrower of claim 28 further comprising fastners extending through the layer into the key portions.
31. The snow thrower of claim 14, wherein the shaft coupler comprises a corner joint interconnecting the hub and the key portions and wherein the impeller further comprises a secondary depression about the aperture receiving the corner joint of the hub such that a face of the key portions lie flush against a floor of the non-circular depression.
32. A snow thrower impeller comprising:
a layer of material having deformed portions such that the layer of material comprises:
a central portion about a rotational axis of the impeller;
a plurality of shovels extending from the central portion, each shovel comprising:
a blade having a snow driving face facing in a direction;
a depression gusset in each blade, the depression gusset forming a first channel on a face of the blade opposite the snow driving face;
an embossed rib in each blade and extending from the depression gusset towards a top of the blade, the embossed rib forms a second channel on the snow driving face; and
a blade support wall extending along a base of the snow driving face and projecting in the direction from the snow driving face, wherein the blade is independently upright with respect to the blade support wall to as to be connected to the impeller solely at the base of the blade.
33. The snow thrower impeller of claim 32, wherein each of the blades has an outermost radial tip with a blade edge, the blade edge having a first radially inward taper.
34. The snow thrower impeller of claim 33, wherein each blade comprises an angled top having a radially outermost top edge, the top edge having a chamfer.
35. The snow thrower impeller of claim 32, wherein each blade comprises an angled top having a radially outermost top edge, the top edge having a chamfer.
36. The snow thrower impeller of claim 32, wherein each blade is configured to bend inwardly and rearwardly when encountering non-snow obstructions while rotating a speed of at least 1200 revolutions per minute.
37. The snow thrower impeller of claim 32, wherein each of the blades has a snow driving face, the snow driving face of each blade facing in a direction about the rotation axis of the impeller and wherein the impeller further comprises louvers extending through the blade support wall, each louver facing in the direction.
38. The snow thrower impeller of claim 37 further comprising a web along a leading ortion of the blade support wall on a same side of the impeller as the snow driving face, the web extending from one of the blades and terminating opposite one of the louvers.
39. The snow thrower impeller of claim 32 further comprising a web along the leading portion of the blade support wall, the web terminating at a notch extending from the web to an outer radial end of the blade support wall.
40. A snow thrower impeller comprising:
a layer of material having deformed portions such that the layer of material comprises:
a central portion about a rotational axis of the impeller; and
a plurality of shovels extending from the central portion, each shovel comprising:
a blade having a snow driving face facing in a direction;
a blade support wall extending along a base of the snow driving face and projecting in the direction from the snow driving face;
a second layer of material the second layer having bent portions such that the second layer of material comprises a second plurality of shovels, each of the second plurality of shovels comprising:
a second blade support wall having a leading portion and a trailing portion; and
a second blade extending from the leading portion of the second blade support wall,
wherein the second layer overlies the first layer and is angularly offset from the first layer to form the impeller having at least four shovels.
41. The snow thrower of claim 40, wherein the first layer comprises a first shovel and a second shovel angularly spaced 180\xb0 from the first shovel, wherein the second layer comprises a third and a fourth shovel angularly spaced 180\xb0 from the third shovel, wherein the first shovel and the second shovel are angularly spaced from one another by 90\xb0.
42. A snow thrower comprising:
an engine;
an auger housing configured to receive a snow;
an auger within the auger housing and operably coupled to the engine so as to be driven by the engine;
an impeller housing configured to receive snow driven by the auger from the auger housing;
a discharge chute extending from the impeller housing; and
an impeller within the impeller housing and operably coupled to the engine so as to be driven by the engine to discharge snow from the impeller housing through the discharge chute, the impeller comprising:
a layer of material formed from cold rolled steel having a thickness of between 0.110 inches and 0.154 inches, the layer having bent portions such that the layer of material comprises a plurality of shovels, each of the plurality of shovels comprising:
a blade support wall having a leading portion and a trailing portion; and
a blade extending from the trailing portion of the blade support wall;
an aperture through the layer; and
a non-circular depression in the layer about the aperture;
wherein the snow thrower further comprises a shaft coupler comprising:
a hub received within the aperture and configured to mount to a shaft; and

key portions extending from the hub and received within the non-circular depression so as to key the hub to the impeller, wherein the shaft coupler comprises a corner joint interconnecting the hub and the key portions and wherein the impeller further comprises a secondary depression about the aperture receiving the corner joint of the hub such that a face of the key portions lie flush against a floor of the non-circular depression.
43. A snow thrower impeller comprising:
a layer of material having deformed portions such that the layer of material comprises:
a central portion about a rotational axis of the impeller; and
a plurality of shovels extending from the central portion, each shovel comprising:
a blade having a snow driving face facing in a direction;
a blade support wall extending along a base of the snow driving face and projecting in the direction from the snow driving face;
a depression gusset in each blade, the depression gusset forming a first channel on a face of the blade opposite the snow driving face; and
an embossed rib in each blade and extending from the depression gusset towards a top of the blade, the embossed rib forms a second channel on the snow driving face.