# US 2018/0299402 A1 · Solid state sensor for metal ion detection and trapping in solution > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0299402 A1 - Document ID: US20180299402A1 - Status: Published application - Kind: A1 - Application number: 16/016,365 - Filed: 2018-06-22 - Published: 2018-10-18 - Earliest claimed: 2010-08-02 - Assignees: Wafertech, LLC - Applicants: WaferTech, LLC - Inventors: Re-Long CHIU; Jason HIGGINS - Web page: https://patentgrep.com/patent/US20180299402A1 ## CPC - G01N 27/414: Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS - G01N 27/07: Construction of measuring vessels; Electrodes therefor - H10P 74/20: characterised by the properties tested or measured, e.g. structural or electrical properties - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A device, apparatus and method for trapping metal ions and detecting metal ion contamination in a solution provide a semiconductor device formed on a semiconductor substrate and including an N-well formed over a P-type substrate and at least a contact portion of the N-well in electrical contact with the solution. When the semiconductor device is optically illuminated, a P/N junction is formed as a result of photovoltaic phenomena. Metal ions from the solution migrate to the contact area due to the voltage created at the P/N junction. The semiconductor device includes a conductive structure with conductive features separated by a gap and therefore in an initially electrically open state. When the ions migrate to the contact area, they precipitate, at least partially bridging the gap and creating conductance through the conductive structure. The conductance may be measured to determine the amount of metal ion contamination. ## Claims ### Claim 1 A device for in-situ detection of metal ion contamination in a solution, comprising: at least one N-type material layer oriented in a first direction and covering a P-type material layer oriented in said first direction; and metal leads formed over said N-type material layer and separated from one another by a gap filled with a first dielectric, wherein said metal leads are separated from portions of said N-type material layer by a second dielectric, wherein portions of said N-type material layer are separated from each other by said first dielectric. ### Claim 2 (depends on 1) A device of claim 1, wherein each of said metal leads directly contacts a respective portion of said N-type material layer at locations adjacent said gap. ### Claim 3 (depends on 1) A device of claim 1, wherein said solution comprises an effluent stream from a semiconductor processing operation and said optically illuminating comprises exposing said semiconductor device to ambient light. ### Claim 4 (depends on 1) A device of claim 1, wherein portions of said metal leads are isolated from the solution by a third dielectric with openings therethrough, wherein the openings in the third dielectric expose said gap and respective ends of said metal leads adjacent said gap. ### Claim 5 (depends on 1) A device of claim 1, wherein a illumination source is used to illuminate said device so as to create a voltage across P/N junction and causing metal ions of said solution to at least partially bridge said gap by migrating to and precipitating upon said metal leads and upon said first dielectric. ### Claim 6 (depends on 1) A device of claim 1, wherein electrical circuitry is coupled to said metal leads so as to measure a conductance between said metal leads across said gap to determine a metal ion concentration in said solution. ### Claim 7 (depends on 5) A device of claim 5, where said illumination source is ambient light. ### Claim 8 An apparatus for in-situ detection of metal ion contamination in a solution, comprising: a semiconductor device contacting a solution, said semiconductor device comprising at least one N-type material layer oriented in a first direction and covering a P-type material layer oriented in said first direction, metal leads formed over said N-type material layer and separated from one another by a gap filled with a dielectric and from portions of said N-type material layer by said dielectric; an illumination source adapted to expose said semiconductor device to illumination; and electrical circuitry coupled to a structure of said semiconductor device and adapted to determine if a conductive path of metal ions from said solution exists between said metal leads and across said gap. ### Claim 9 (depends on 8) The apparatus as in claim 8, wherein said solution comprises an effluent stream from a semiconductor processing tool. ### Claim 10 (depends on 8) The apparatus as in claim 8, wherein said illumination source comprises a white light disposed within said solution. ### Claim 11 (depends on 8) The apparatus as in claim 8, wherein said semiconductor device further comprises a transparent dielectric over said metal leads, said transparent dielectric including openings that expose said gap and respective ends of each of said metal leads adjacent said gap. ### Claim 12 (depends on 8) The apparatus as in claim 8, wherein said semiconductor device further comprises further metal leads formed over said N-type material layer and arranged in further pairs, each of said further pairs including two said further metal leads separated by said dielectric, wherein said further pairs include different spacing distances of said further metal leads. ### Claim 13 (depends on 8) The apparatus as in claim 8, wherein said electrical circuitry is further coupled to said further pairs of metal leads and is adapted to determine if a conductive path of said metal ions exists between respective further metal leads of said further pairs. ### Claim 14 An apparatus for in-situ detection of metal ion contamination in a solution, comprising: a vessel containing a solution; a semiconductor device contacting said solution, said semiconductor device comprising at least one N-type material layer oriented in a first direction and covering a P-type material layer oriented in said first direction, metal leads formed over said N-type material layer and separated from one another by a gap filled with a dielectric and from portions of said N-type material layer by said dielectric; an illumination source adapted to expose said semiconductor device to illumination; and electrical circuitry coupled to a structure of said semiconductor device and adapted to determine if a conductive path of metal ions from said solution exists between said metal leads and across said gap. ### Claim 15 (depends on 14) The apparatus as in claim 14, wherein said vessel comprises a pipe and said solution comprises an effluent stream from a semiconductor processing tool. ### Claim 16 (depends on 15) The apparatus as in claim 15, wherein said semiconductor processing tool comprises a chemical mechanical polishing (CMP) processing tool. ### Claim 17 (depends on 14) The apparatus as in claim 14, wherein said illumination source comprises a white light disposed within said solution. ### Claim 18 (depends on 14) The apparatus as in claim 14, wherein said semiconductor device further comprises a transparent dielectric over said metal leads, said transparent dielectric including openings that expose said gap and respective ends of each of said metal leads adjacent said gap. ### Claim 19 (depends on 14) The apparatus as in claim 14, wherein said semiconductor device further comprises further metal leads formed over said N-type material layer and arranged in further pairs, each of said further pairs including two said further metal leads separated by said dielectric, wherein said further pairs include different spacing distances of said further metal leads. ### Claim 20 (depends on 19) The apparatus as in claim 19, wherein said electrical circuitry is further coupled to said further pairs of metal leads and is adapted to determine if a conductive path of said metal ions exists between respective further metal leads of said further pairs.