# US 2019/0355673 A1 · Electronic chip > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0355673 A1 - Document ID: US20190355673A1 - Status: Published application - Kind: A1 - Application number: 16/409,704 - Filed: 2019-05-10 - Published: 2019-11-21 - Earliest claimed: 2018-05-15 - Assignees: STMicroelectronics (Rousset) SAS - Applicants: Stmicroelectronics (Rousset) SAS - Inventors: Alexandre SARAFIANOS; Bruno NICOLAS; Daniele FRONTE - Web page: https://patentgrep.com/patent/US20190355673A1 ## CPC - G06F 21/75: by inhibiting the analysis of circuitry or operation - H10W 42/405: {using active circuits} - G01N 27/041: {of a solid body} - G01N 27/045: {Circuits (measuring resistance per se G01R27/00, e.g. G01R27/22)} - H10W 20/43: Layouts of interconnections - H10W 20/498: {Resistive arrangements or effects of, or between, wiring layers} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - 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) ## Abstract The disclosure concerns an electronic chip including a resistive region and a first switch of selection of a first area in contact with the resistive region. ## Claims ### Claim 1 An electronic chip comprising: a resistive region; a first contact area in contact with the resistive region; and a first switch configured to select the first contact area in contact with the resistive region. ### Claim 2 (depends on 1) The chip of claim 1, wherein the resistive region is coil-shaped. ### Claim 3 (depends on 1) The chip of claim 1, further comprising first wells, wherein the resistive region comprises a second well buried under the first wells. ### Claim 4 (depends on 3) The chip of claim 3, wherein the second well is separated from the first wells. ### Claim 5 (depends on 1) The chip of claim 1, wherein the resistive region is a metal track located on a surface of the chip. ### Claim 6 (depends on 1) The chip of claim 1, comprising a semiconductor substrate, wherein the resistive region is formed in the semiconductor substrate. ### Claim 7 (depends on 1) The chip of claim 1, comprising: a second contact area in contact with the resistive region; and a second switch configured to select the second contact area in contact with the resistive region. ### Claim 8 (depends on 7) The chip of claim 7, wherein the first and second areas are located on a side of a surface of the chip. ### Claim 9 (depends on 7) The chip of claim 7, further comprising a detector configured to detect a difference between measured and expected electric resistance values between the first and second areas. ### Claim 10 (depends on 9) The chip of claim 9, wherein said expected value is a selected value. ### Claim 11 (depends on 10) The chip of claim 10, wherein the selected value is randomly selected. ### Claim 12 (depends on 1) The chip of claim 1, comprising: a selector configured to sequentially select a plurality of pairs of first and second areas, wherein the resistive region includes a respective resistor between the first and second areas of each pair, each respective resistor having an electric resistance that is expected to have an expected value; and a detector configured to detect measured values of electric resistance between the first and second areas of each of the pairs and detect a difference between the measured value and the expected value for each pair of first and second areas. ### Claim 13 A method of protecting an electronic chip against an attack, the method comprising: selecting first and second contact areas coupled to respective first and second portions of a resistive region of the electronic chip; determining a measured resistance value of a portion of the resistive region between the first and second portions; and comparing with a threshold a difference between the measured resistance value and an expected value. ### Claim 14 (depends on 13) The method of claim 13, wherein the selecting, determining, and comparing steps are performed in response to starting the electronic chip. ### Claim 15 An electronic chip comprising: a resistive region; a node; and a connection device configured to connect to the node a selectable number of first contact areas in contact with the resistive region. ### Claim 16 (depends on 15) The chip of claim 15, wherein the resistive region is defined by a semiconductor substrate. ### Claim 17 (depends on 15) The chip of claim 15, wherein said number is randomly selectable. ### Claim 18 (depends on 15) The chip of claim 15, wherein said number is selectable between 1 and 16. ### Claim 19 (depends on 15) The chip of claim 15, wherein the first areas are selectable from among regularly distributed areas. ### Claim 20 (depends on 16) The chip of claim 16, further comprising a detector configured to detect a difference between measured and expected electric resistance values between said node and a second contact area in contact with the resistive region. ### Claim 21 A device comprising: an electronic chip that includes: a resistive region; a node; and a connection device configured to connect to the node a selectable number of first contact areas in contact with the resistive region; and a selector configured to select the number of first contact areas. ### Claim 22 (depends on 21) The device of claim 21, comprising a metal plate located against a back side of the chip. ### Claim 23 (depends on 22) The device of claim 22, wherein the first areas are located on a front side of the chip. ### Claim 24 A method of protecting a device against an attack, the method comprising: selecting a number of first contact areas coupled to respective portions of a resistive region of an electronic chip of the device; connecting the first contact areas to a node; determining a measured resistance value of a portion of the resistive region between the first contacts; and comparing with a threshold a difference between the measured resistance value and an expected value. ### Claim 25 (depends on 24) The method of claim 24, wherein the selecting, connecting, determining, and comparing steps are performed in response to starting the electronic chip.