Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant's election with traverse of Group I and Species L which is believed to include claims 1-17 in the reply filed on 06/29/2026 is acknowledged. The traversal is on the ground(s) that the election/restriction requirement fails to show that the identified species are independent and distinct…. A showing of serious burden has not been made……The election/restriction requirement is based on the incorrect assertion that all of the identified species are mutually exclusive” pages 1-3.
This is found persuasive therefore the elected species are withdrawn.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Loechelt (Patent No.: US 9620585).
Re claim 1, Loechelt, FIG. 2A teaches a method of forming an edge termination structure in a semiconductor device, the semiconductor device including an active region (111), in which one or more active structures are formed, and an edge termination region (116), in which the edge termination structure is formed, the edge termination region being laterally adjacent to the active region, the method comprising:
forming an epitaxial layer (206/208, col. 5, lines 50-55) on a semiconductor substrate (202), the epitaxial layer extending laterally across the active (111) and edge termination regions (116);
forming a plurality of active trenches (four on the right) in the active region and at least one outer trench (two on the left) in the edge termination region, each of the outer and active trenches extending vertically through at least a portion of the epitaxial layer;
at least partially filling each of the outer and active trenches with a first insulating material (224, col. 8, lines 44-46);
forming a moat (227) by etching an area of the epitaxial layer in the edge termination region (116) proximate to a last one of the plurality of active trenches (216) in the active region (111);
at least partially filling the moat with a second insulating material (“the trench fill 227 may also be formed from dielectric deposition”, col. 8, lines 59-60, note that in this case it was obvious be a dielectric material), to form a moat structure as the non-conducting edge termination structure (116) in a semiconductor device.
Re claim 2, Loechelt, FIG. 2A teaches the method according to claim 1, further comprising:
forming at least one boundary trench (214) in the edge termination region (116), the boundary trench extending vertically through at least a portion of the epitaxial layer (206/208) and being spaced laterally from the at least one outer trench; and
at least partially filling the at least one boundary trench with the first insulating material (224),
wherein the moat structure (227) is disposed between the outer and boundary trenches, such that a given sidewall of the moat structure is defined by one of the outer and boundary trenches.
Re claim 3, Loechelt, FIG. 2A teaches the method according to claim 2, wherein the outer, boundary and active trenches are formed concurrently using a same mask (302, FIG. 3D, col. 7, lines 8-17) and in a same processing step.
Re claim 9, Loechelt, FIG. 2A teaches the method according to claim 1, further comprising:
forming a first conductive layer (236) on an upper surface of at least the active region; and
forming a second metal layer (248, col. 10, lines 30-35) on an upper surface of the first conductive layer (236) and extending laterally over the at least one outer trench and over a portion of the second insulating layer (227) in the moat structure to form a field plate in the edge termination region.
Sylvain differs from the invention by not showing a first conductive layer is made of metal material.
However, it would have been obvious to one having ordinary skill in the art at the time of the invention was made to include the above said teaching because metal material is a very well-known material for making a contact since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416.
Re claim 10, Loechelt, FIG. 2A teaches the method according to claim 9, further comprising controlling an amount of extension of the second metal layer (248) over the moat structure in the edge termination region (116) to optimize an electric field distribution in the moat structure (the two [227/224] on the left).
Re claim 11, Loechelt, FIG. 2A teaches the method according to claim 1, further comprising:
forming a first conductive layer (236) on an upper surface of at least the active region (206/208) and extending laterally over the at least one outer trench and a portion of the moat structure in the edge termination region (116), an extension of the first conductive layer over the moat structure forming a first field plate in the edge termination region;
forming a second metal layer (248) on an upper surface of the first conductive layer (236) and extending laterally over a portion of the second insulating layer in the moat structure to form a second field plate in the edge termination region (116); and
controlling an amount of extension of at least one of the first and second metal layers (236/248) over the moat structure in the edge termination region to optimize an electric field distribution in the moat structure.
Sylvain differs from the invention by not showing a conductive layer is made of metal material.
However, it would have been obvious to one having ordinary skill in the art at the time of the invention was made to include the above said teaching because metal material is a very well-known material for making a contact since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416.
Re claim 12, Loechelt, FIG. 2A teaches the method according to claim 2, further comprising:
forming a first conductive layer (236) on an upper surface of at least the active region (111), a first part of the first conductive layer extending laterally from the active region, over the at least one outer trench (214) and over a portion of the moat structure (224/227), to form a primary inner field plate in the edge termination region (116); and
forming a second part of the first conductive layer (far left portion of 236) extending laterally over the epitaxial layer (206/208), over the at least one boundary trench (two on the left) and over a portion of the moat structure, to form a primary outer field plate in the edge termination region (116).
Re claim 13, Loechelt, FIG. 2A teaches the method according to claim 2, further comprising:
forming a first conductive layer (236) on an upper surface of at least the active region (111), a portion of the first conductive layer extending laterally over the epitaxial layer (206/208), over the at least one boundary trench and over a portion of the moat structure (224/227) proximate the at least one outer trench, to form a primary outer field plate in the edge termination region (116); and
forming a second metal layer (248) on an upper surface of the first conductive layer (236) and extending laterally over a portion of the second insulating layer (227) in the moat structure proximate the at least one outer trench, to form a secondary outer field plate in the edge termination region (116).
Re claim 14, Loechelt, FIG. 2A teaches the method according to claim 2, further comprising:
forming a first conductive layer (236) on an upper surface of at least the active region (111);
forming a first part of a second metal layer (248) on an upper surface of the first conductive layer (236) and extending laterally over the at least one outer trench and a portion of the second insulating layer (227) in the moat structure proximate the at least one outer trench to form an inner field plate in the edge termination region (116); and
forming a second part of the second metal layer (middle hollow portion of 248) on the second insulating layer (227) over the at least one boundary trench and a portion of the moat structure (224/227) proximate the at least one boundary trench to form an outer field plate in the edge termination region (116).
In re claims 12-14, Sylvain differs from the invention by not showing a first conductive layer is made of metal material.
However, it would have been obvious to one having ordinary skill in the art at the time of the invention was made to include the above said teaching because metal material is a very well-known material for making a contact since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416.
Re claim 15, Loechelt, FIG. 2A teaches the method according to claim 14, further comprising controlling an amount of extension of the first and second parts of the second metal layer (248) over the moat structure (224/227) in the edge termination region (116) to optimize an electric field distribution in the moat structure.
Re claim 16, Loechelt, FIG. 2A teaches the method according to claim 1, further comprising forming the at least one outer trench (214) and the moat (224/227) such that a depth of the at least one outer trench is greater than a depth of the moat in the edge termination region (116).
Re claim 17, Loechelt, FIG. 2A teaches the method according to claim 1, further comprising controlling a width of a mesa area between a last one of the plurality of active trenches (214) in the active region (111) and the outer trench (214) in the edge termination region (116) to accommodate a difference in charge between the moat structure and the plurality of active trenches.
Claim(s) 1-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sylvain et al. (Title “An improved termination design using deep trench for super-junction Power Device”) (hereinafter Sylvain) in view of Wentao Yang et al. (Title “Desing and Characterization of Sloped-Field-Plate enhanced trench edge termination”) (hereinafter Wentao) filed in the IDS on 8/6/2024.
Re claim 1, Sylvain, Fig. 1 teaches a method of forming an edge termination structure in a semiconductor device, the semiconductor device including an active region, in which one or more active structures are formed, and an edge termination region, in which the edge termination structure is formed, the edge termination region being laterally adjacent to the active region, the method comprising:
forming an epitaxial layer (N-) on a semiconductor substrate (N+), the epitaxial layer extending laterally across the active (Elementary cells) and edge termination regions (Termination);
forming a plurality of active trenches (three on the left) in the active region and at least one outer trench (one big one on the right) in the edge termination region, each of the outer and active trenches extending vertically through at least a portion of the epitaxial layer;
at least partially filling each of the outer and active trenches with a conductive doping material (P+);
forming a moat by etching an area of the epitaxial layer in the edge termination region (to get the inner boundary of P+ as shown in Fig. 2) proximate to a last one of the plurality of active trenches (three trenches) in the active region;
at least partially filling the moat with a second insulating material (BSB (Cyclotene 4026-46) filled, page 1, left column), to form a moat structure as the non-conducting edge termination structure in a semiconductor device.
Sylvain fails to teach at least partially filling each of the outer and active trenches with a first insulating material.
Wentao teaches at least partially filling each of the outer and active trenches with a first insulating material (oxide, Fig. 2, page 2).
It would have been obvious for a person of ordinary skill in the art before the effective filing date of the claim invention to include the above said teaching for the purpose of achieving the ideal planer junction breakdown voltage and high dv/di performance as taught by Wentao, Abstract.
Re claim 2, in the combination, Wentao, Fig. 2 teaches the method according to claim 1, further comprising:
forming at least one boundary trench in the edge termination region, the boundary trench extending vertically through at least a portion of the epitaxial layer (N- drift region) and being spaced laterally from the at least one outer trench; and
at least partially filling the at least one boundary trench with the first insulating material (Oxide),
wherein the moat structure (BCB) is disposed between the outer and boundary trenches, such that a given sidewall of the moat structure is defined by one of the outer and boundary trenches.
Re claim 4, in the combination, Sylvain, Fig. 1 teaches the method according to claim 1, wherein a first width of the at least one outer trench (on the far right) is greater than a second width of each of the plurality of active trenches (three active trenches on the left [based on the drawing scale]).
Re claim 5, in the combination, Sylvain, Fig. 1 teaches the method according to claim 4, wherein the first width (horizontal width of the on the far right) is at least twice the second width (horizontal width of three active trenches on the left [based on the drawing scale]).
Re claim 6, in the combination, Sylvain, Fig. 1 teaches the method according to claim 2, wherein each of the at least one outer trench, the at least one boundary trench, and the plurality of active trenches is formed using a deep trench etch process having an aspect ratio of greater than about 10 to 1 (vertical length/horizontal width [based on the drawing scale]).
In re claims 4-6, Drawings and pictures can anticipate claims if they clearly show the structure which is claimed. In re Mraz, 455 F.2d 1069, 173 USPQ 25 (CCPA 1972). However, the picture must show all the claimed structural features and how they are put together. Jockmus v. Leviton, 28 F.2d 812 (2d Cir. 1928). The origin of the drawing is immaterial. For instance, drawings in a design patent can anticipate or make obvious the claimed invention as can drawings in utility patents. When the reference is a utility patent, it does not matter that the feature shown is unintended or unexplained in the specification. The drawings must be evaluated for what they reasonably disclose and suggest to one of ordinary skill in the art. In re Aslanian, 590 F.2d 911, 200 USPQ 500 (CCPA 1979). See MPEP § 2121.04 for more information on prior art drawings as “enabled disclosures.”
Re claim 7, in the combination, Sylvain, Figs. 1-2 teaches the method according to claim 1, further comprising forming a first conductive layer (horizontal layer P+ on the left) on an upper surface of at least the active region, wherein the first conductive layer is configured to extend laterally over the at least one outer trench and over a portion of the moat structure (BCB/P+) in the edge termination region, an extension of the first conductive layer over the moat structure forming a field plate (Field plate) in the edge termination region.
Re claim 8, in the combination, Sylvain, Figs. 1-2 teaches the method according to claim 7, further comprising controlling an amount of extension of the first conductive layer (horizontal layer P+ on the left) over the moat structure in the edge termination region to optimize an electric field distribution in the moat structure (BCB).
Re claim 9, in the combination, Sylvain, Figs. 1-2 teaches the method according to claim 1, further comprising:
forming a first conductive layer (horizontal layer P+ on the left) on an upper surface of at least the active region; and
forming a second metal layer (Field plate) on an upper surface of the first metal layer and extending laterally over the at least one outer trench and over a portion of the second insulating layer in the moat structure to form a field plate in the edge termination region.
In re claims 7-9. Sylvain differs from the invention by not showing a conductive layer is made of metal material.
However, it would have been obvious to one having ordinary skill in the art at the time of the invention was made to include the above said teaching because metal material is a very well-known material for making a contact since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416.
Re claim 10, in the combination, Sylvain, Fig. 1 teaches the method according to claim 9, further comprising controlling an amount of extension of the second metal layer (Field plate) over the moat structure in the edge termination region to optimize an electric field distribution in the moat structure (BCB).
Conclusion
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/TONY TRAN/Primary Examiner, Art Unit 2893
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