We claim:
1. A two-stage retrofit filter adapted for use with an electrical discharge machine (EDM) of the type wherein a one-stage filter is placed in a tank over an apertured standpipe such that a fluid being filtered flows through the apertured standpipe and filter, the retrofit EDM filter comprising:
a plurality of nested filter elements, including an inner element and an outer element, the physical configuration of the elements being such that the retrofit filter may be placed in the same tank and over the apertured standpipe used for the one-stage filter, so that the fluid to be filtered now flows through the apertured standpipe and each of the filter elements.
2. The retrofit EDM filter of claim 1, wherein the fluid being filtered flows from the EDM work table tank to the apertured standpipe, and into the inner filter element.
3. The retrofit EDM filter of claim 1, wherein the filter elements are cylindrical.
4. The retrofit EDM filter of claim 1, wherein the filter elements are pleated.
5. The retrofit EDM filter of claim 1, wherein the filter elements are composed of a technical grade filter paper.
6. The retrofit EDM filter of claim 1, wherein the fluid to be filtered flows through the inner element and the outer element substantially at different times.
7. The retrofit EDM filter of claim 6, further comprising:
a pressure-operated valve associated with the inner filter, the valve being such that when a predetermined pressure is reached due to the entrapment of contaminants by the inner filter, the valve opens to allow the fluid to be filtered to flow through the outer filter.
8. The retrofit EDM filter of claim 7, wherein:
at least the inner filter element is pleated; and
the pleatings are reinforced at least in the vicinity of the pressure-operated release valve to ensure that the pleatings do not interfere with the opening or flow through the valve.
9. The retrofit EDM filter of claim 6, further comprising:
a pressure-operated arrangement wherein the inner filter element moves relative to the outer filter element when a predetermined pressure is reached due to the entrapment of contaminants by the inner filter, thereby allowing the fluid to be filtered to flow past the inner filter and through the outer filter.
10. The retrofit EDM filter of claim 6, wherein the construction of the inner filter element is such that it tears, decomposes, or disintegrates when a predetermined pressure is reached due to the entrapment of contaminants by the inner filter, thereby allowing the fluid to be filtered to flow past or through the inner filter and through the outer filter.
11. The retrofit EDM filter of claim 1, wherein:
the fluid to be filtered flows through the filter elements at substantially the same time; and
the construction or composition of the elements is such that the fluid is filtered to a first level by the inner element, then filtered to a second level by the outer element.
12. The retrofit EDM filter of claim 11, wherein:
the inner element includes apertures or perforations allowing a portion of the fluid to flow therethrough without being filtered; and
the portion is filtered by the outer filter.
13. A two-stage retrofit filter adapted for use with an electrical discharge machine (EDM) of the type wherein a one-stage filter is placed in a tank over an central, apertured standpipe, such that a fluid to be filtered flows up through the bottom of the tank, out the apertured standpipe, and into the filter, the retrofit EDM filter comprising:
a plurality of nested cylindrical pleated filter elements, including an inner element and an outer element, the physical configuration of the elements being such that the retrofit filter may be placed in the same tank and over the apertured standpipe used for the one-stage filter, so that the fluid to be filtered now flows through the apertured standpipe and each of the filter elements.
14. The retrofit EDM filter of claim 13, wherein the filter elements are composed of a technical grade filter paper.
15. The retrofit EDM filter of claim 13, further comprising:
a pressure-operated valve associated with the inner filter, the valve being such that when a predetermined pressure is reached due to the entrapment of contaminants by the inner filter, the valve opens to allow the fluid to be filtered to flow through the outer filter.
16. The retrofit EDM filter of claim 15, wherein:
the pleatings are reinforced at least in the vicinity of the pressure-operated release valve to ensure that the pleatings do not interfere with the opening or flow through the valve.
17. The retrofit EDM filter of claim 13, further comprising:
a pressure-operated arrangement wherein the inner filter element moves relative to the outer filter element when a predetermined pressure is reached due to the entrapment of contaminants by the inner filter, thereby allowing the fluid to be filtered to flow past the inner filter and through the outer filter.
18. The retrofit EDM filter of claim 13, wherein the construction of the inner filter element is such that it tears, decomposes, or disintegrates when a predetermined pressure is reached due to the entrapment of contaminants by the inner filter, thereby allowing the fluid to be filtered to flow past or through the inner filter and through the outer filter.
19. The retrofit EDM filter of claim 13, wherein:
the fluid to be filtered flows through the filter elements at substantially the same time; and
the construction or composition of the elements is such that the fluid is filtered to a first level by the inner element, then filtered to a second level by the outer element.
20. The retrofit EDM filter of claim 19, wherein:
the inner element includes apertures or perforations allowing a portion of the fluid to flow therethrough without being filtered; and
the portion is filtered by the outer filter.
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:
at least one SRAM cell,
wherein the SRAM cell includes a pull-up transistor, a pull-down transistor, and a pass-gate transistor, and
an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from a Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor, and
wherein a nitrogen concentration of a gate insulating film of the pass-gate transistor is different from a nitrogen concentration of a gate insulating film of the pull-up transistor and a nitrogen concentration of a gate insulating film of the pull-down transistor.
2. The semiconductor device of claim 1, wherein the gate insulating film of each of the transistors comprises a high-k material.
3. The semiconductor device of claim 1, wherein an interface film is formed between a substrate and the gate insulating film of each of the transistors, and
a nitrogen concentration of the interface film of the pass-gate transistor is different from a nitrogen concentration of the interface film of the pull-up transistor and a nitrogen concentration of the interface film of the pull-down transistor.
4. The semiconductor device comprising:
at least one SRAM cell,
wherein the SRAM cell includes a pull-up transistor, a pull-down transistor, and a pass-gate transistor, and
an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor, and
wherein a gate electrode of each of the transistors comprises a first metal electrode formed on the gate insulating film and a second metal electrode formed on the first metal electrode, and
a thickness of the second metal electrode of the pass-gate transistor is different from a thickness of the second metal electrode of the pull-up transistor and a thickness of the second metal electrode of the pull-down transistor.
5. The semiconductor device of claim 4, wherein the first metal electrode of each of the transistors comprises LaO, Y2O3, Lu2O3, SrO, or a combination thereof.
6. The semiconductor device of claim 4, wherein the second metal electrode of each of the transistors comprises TiN, TaN, or a combination thereof.
7. A semiconductor device comprising:
at least one SRAM cell, comprising:
a pull-up transistor,
a pull-down transistor, and
a pass-gate transistor,
wherein a nitrogen concentration of a gate insulating film of the pass-gate transistor is different from a nitrogen concentration of a gate insulating film of the pull-up transistor and a nitrogen concentration of a gate insulating film of the pull-down transistor.
8. The semiconductor device of claim 7, wherein the gate insulating film of each of the transistors comprises a high-k material.
9. The semiconductor device of claim 7, wherein:
an interface film is formed between a substrate and the gate insulating film of each of the transistors, and
a nitrogen concentration of the interface film of the pass-gate transistor is different from a nitrogen concentration of the interface film of the pull-up transistor and a nitrogen concentration of the interface film of the pull-down transistor.
10. The semiconductor device of claim 7, wherein:
a gate electrode of each of the transistors includes a first metal electrode formed on a gate insulating film and a second metal electrode formed on the first metal electrode, and
a thickness of the second metal electrode of the pass-gate transistor is different from a thickness of the second metal electrode of the pull-up transistor and a thickness of the second metal electrode of the pull-down transistor.
11. The semiconductor device of claim 10, wherein the first metal electrode of each of the transistors comprises LaO, Y2O3, Lu2O3, SrO, or a combination thereof.
12. The semiconductor device of claim 10, wherein the second metal electrode of each of the transistors comprises TiN, TaN, or a combination thereof.
13. The semiconductor device of claim 7, wherein an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from a Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor.
14. An electronic system comprising a semiconductor device, including:
at least one SRAM device comprising:
a pull-up transistor,
a pull-down transistor, and
a pass-gate transistor, wherein the nitrogen characteristics of the pass-gae transistor are different from nitrogen characteristics of the pull-up transistor and pull-down transistor;
a controller;
an inputoutput (IO) device;
an interface; and
a bus configured to interconnect one or more of the controller, the IO device, and the interface.
15. The system of claim 14, wherein a nitrogen concentration of a gate insulating film of the pass-gate transistor is different from a nitrogen concentration of a gate insulating film of the pull-up transistor and a nitrogen concentration of a gate insulating film of the pull-down transistor.
16. The system of claim 14, wherein the gate insulating film of each of the transistors comprises a high-k material.
17. The system of claim 14, wherein:
an interface film is formed between a substrate and the gate insulating film of each of the transistors, and
a nitrogen concentration of the interface film of the pass-gate transistor is different from a nitrogen concentration of the interface film of the pull-up transistor and a nitrogen concentration of the interface film of the pull-down transistor.
18. The system of claim 14, wherein:
a gate electrode of each of the transistors includes a first metal electrode formed on a gate insulating film and a second metal electrode formed on the first metal electrode, and
a thickness of the second metal electrode of the pass-gate transistor is different from a thickness of the second metal electrode of the pull-up transistor and a thickness of the second metal electrode of the pull-down transistor.
19. The system of claim 14, wherein an inversion-layer thickness (Tinv) of a gate stack of the pass-gate transistor is different from a Tinv of a gate stack of the pull-up transistor and Tinv of a gate stack of the pull-down transistor.