COUNTERMEASURE METHOD AND DEVICE FOR PROTECTING DATA CIRCULATING IN AN ELECTRONIC MICROCIRCUIT

• US 20130015900A1
• Filed: 09/24/2012
• Published: 01/17/2013
• Est. Priority Date: 03/24/2010
• Status: Active Grant

• Current Assignee: Stmicroelectronics Rousset SAS (STMicroelectronics NV)
• Original Assignee: Stmicroelectronics Rousset SAS (STMicroelectronics NV)
• Inventors: Marinet, Fabrice, Lisart, Mathieu
• Granted Patent: US 8,819,609 B2
• Time in Patent Office: Days
• US Class Current: 327/306
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: G06K 19/07309 Means for preventing undesired reading or writing from or onto record carriers
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 23/576 using active circuits
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H03K 19/003 Modifications for increasing the reliability for protection
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators
• CPC Class Codes: H04L 2209/12 Details relating to cryptographic hardware or logic circuitry
• CPC Class Codes: H04L 9/004 for fault attacks
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

The disclosure relates to a countermeasure method in an electronic microcircuit, comprising successive process phases executed by a circuit of the microcircuit, and adjusting a power supply voltage between power supply and ground terminals of the circuit, as a function of a random value generated for the process phase, at each process phase executed by the circuit.

Claims

1. A method of making an electronic microcircuit, comprising:

forming a processing circuit configured to execute successive process phases, the forming including;

forming in a substrate an isolated well electrically isolated from an underlying portion of the substrate; and

forming a power supply terminal and a ground terminal of the processing circuit, wherein at least one of the power supply and ground terminals is formed in the isolated well; and

forming a power supply circuit configured to, for each of the processing phases, adjust a power supply voltage between the power supply and ground terminals of the processing circuit as a function of a varying signal.

2. A method according to claim 1, wherein forming the power supply circuit includes forming the power supply circuit configured to:

detect inactive phases between the successive active phases; and

adjust the power supply voltage as a function of the varying signal in response to detecting the inactive phases.

3. A method according to claim 1, wherein forming the power supply circuit includes forming the power supply circuit configured to adjust the power supply voltage between the power supply and ground terminals of the processing circuit in a determined range as a function of:

variations of the power supply voltage resulting from variations of performances of the processing circuit linked to variations of an ambient temperature and variations of manufacturing conditions of the microcircuit,

variations of the power supply voltage and ground voltages of the microcircuit as a function of an extent of activity of the microcircuit, and

minimum voltages allowing a switching of N-channel and P-channel transistors of the microcircuit to be performed.

4. A method according to claim 1, wherein forming the power supply circuit includes forming the power supply circuit configured to adjust a bias voltage between the ground terminal of the circuit and a ground terminal of the microcircuit as a function of a random value, a voltage difference between a power supply voltage of the microcircuit and the power supply terminal of the processing circuit being fixed.

5. A method according to claim 4, wherein forming the power supply circuit includes forming the power supply circuit configured to adjust the power supply voltage between the power supply and ground terminals of the processing circuit is performed in a range included between −

5% to +5% of the power supply voltage of the microcircuit.

6. A method according to claim 1, wherein forming the power supply circuit includes forming the power supply circuit configured to adjust the voltage difference between a power supply terminal of the processing circuit and a power supply voltage of the microcircuit as a function of a random value while a voltage between the ground terminal of the processing circuit and a ground terminal of the microcircuit is fixed.

7. A method according to claim 6, wherein forming the power supply circuit includes forming the power supply circuit configured to adjust the power supply voltage between the power supply and ground terminals of the processing in a range included between −

5% to +5% around the power supply voltage of the microcircuit.

8. A method according to claim 1, wherein forming the power supply circuit includes forming the power supply circuit configured to adjust the power supply voltage between the power supply and ground terminals of the processing circuit with an adjusting step from 0.05 to 0.3% of the power supply voltage of the microcircuit.

9. A method according to claim 1, wherein the varying signal is a randomly varying signal.

10. A method according to claim 1, wherein the varying signal is an alternating signal having an equiprobable distribution and a period corresponding to a duration of one of more successive process phases.

11. A microcircuit comprising:

a first processing circuit configured to execute first successive process phases and including power supply and ground terminals, wherein at least one of the power supply and ground terminals is formed in an isolated well of a substrate, the isolated well being electrically isolated from an underlying portion of the substrate; and

a first power supply circuit coupled to the first processing circuit and configured to, for each of the processing phases, adjust a power supply voltage between the power supply and ground terminals of the processing circuit as a function of a first varying signal.

12. A microcircuit according to claim 11, comprising:

a second processing circuit configured to execute second successive process phases and including power supply and ground terminals; and

a second power supply circuit configured to, for each of the second successive processing phases, adjust a power supply voltage between the power supply and ground terminals of the second processing circuit as a function of a second varying signal.

13. A microcircuit according to claim 11, wherein the first power supply circuit includes:

a comparator having first and second input terminals and an output terminal, the first input terminal being configured to receive a reference voltage;

first and second resistors coupled between the power supply terminal and the output terminal of the comparator, the first resistor being a variable transistor with a control terminal, and the first and second resistors being coupled to each other at the second input terminal of the comparator; and

a random signal generator coupled to the control terminal of the first resistor and configured to generate a random signal to randomly vary a resistance of the first resistor.

14. A microcircuit according to claim 11, further comprising:

microcircuit power supply and ground terminals, wherein the first power supply circuit includes;

a comparator having first and second input terminals and an output terminal, the second input terminal being coupled to the output terminal;

a variable resistor and a current source coupled between the microcircuit power supply and ground terminals, the variable resistor having a control terminal, and the variable resistor and current source being coupled to each other at the first input terminal of the comparator; and

a random signal generator coupled to the control terminal of the variable resistor and configured to generate a random signal to randomly vary a resistance of the variable resistor.

15. A microcircuit according to claim 11, further comprising:

microcircuit power supply and ground terminals, wherein the first power supply circuit includes;

a comparator having first and second input terminals and an output terminal, the first input terminal being coupled to the output terminal;

a first resistor, a second resistor, and a first transistor coupled in series between the microcircuit power supply and ground terminals, the first resistor being a variable transistor with a control terminal, and the first and second resistors being coupled to each other at the second input terminal of the comparator, the first transistor having a control terminal;

a random signal generator coupled to the control terminal of the variable resistor and configured to generate a random signal to randomly vary a resistance of the variable resistor;

a second transistor coupled between the microcircuit power supply terminal and the power supply terminal of the first processing circuit, the second transistor having a control terminal; and

a voltage step up circuit coupled between the output of the comparator and the control terminals of the first and second transistors.

16. A microcircuit according to claim 11, wherein the first power supply circuit is configured to detect inactive phases between the successive active phases of the first processing circuit and adjust the power supply voltage between power supply and ground terminals of the first processing circuit, as a function of the varying signal during the inactive phases between the successive process phases of the first processing circuit, in response to detecting the inactive phases.

17. A microcircuit portable device, comprising:

a support; and

a microcircuit carried by the support and including;

a first processing circuit configured to execute first successive process phases and including power supply and ground terminals, wherein at least one of the power supply and ground terminals is formed in an isolated well of a substrate, the isolated well being electrically isolated from an underlying portion of the substrate; and

a first power supply circuit coupled to the first processing circuit and configured to, for each of the processing phases, adjust a power supply voltage between the power supply and ground terminals of the processing circuit as a function of a first varying signal.

18. A microcircuit portable device according to claim 17, wherein the microcircuit includes:

a second processing circuit configured to execute second successive process phases and including power supply and ground terminals; and

a second power supply circuit configured to, for each of the second successive processing phases, adjust a power supply voltage between the power supply and ground terminals of the second processing circuit as a function of a second varying signal.

19. A microcircuit portable device according to claim 17, wherein the first power supply circuit includes:

a comparator having first and second input terminals and an output terminal, the first input terminal being configured to receive a reference voltage;

first and second resistors coupled between the power supply terminal and the output terminal of the comparator, the first resistor being a variable transistor with a control terminal, and the first and second resistors being coupled to each other at the second input terminal of the comparator; and

a random signal generator coupled to the control terminal of the first resistor and configured to generate a random signal to randomly vary a resistance of the first resistor.

20. A microcircuit portable device according to claim 17, wherein the microcircuit includes:

microcircuit power supply and ground terminals, wherein the first power supply circuit includes;

a comparator having first and second input terminals and an output terminal, the second input terminal being coupled to the output terminal;

a variable resistor and a current source coupled between the microcircuit power supply and ground terminals, the variable resistor having a control terminal, and the variable resistor and current source being coupled to each other at the first input terminal of the comparator; and

a random signal generator coupled to the control terminal of the variable resistor and configured to generate a random signal to randomly vary a resistance of the variable resistor.

21. A microcircuit portable device according to claim 17, wherein the microcircuit includes:

microcircuit power supply and ground terminals, wherein the first power supply circuit includes;

a comparator having first and second input terminals and an output terminal, the first input terminal being coupled to the output terminal;

a first resistor, a second resistor, and a first transistor coupled in series between the microcircuit power supply and ground terminals, the first resistor being a variable transistor with a control terminal, and the first and second resistors being coupled to each other at the second input terminal of the comparator, the first transistor having a control terminal;

a random signal generator coupled to the control terminal of the variable resistor and configured to generate a random signal to randomly vary a resistance of the variable resistor;

a second transistor coupled between the microcircuit power supply terminal and the power supply terminal of the first processing circuit, the second transistor having a control terminal; and

a voltage step up circuit coupled between the output of the comparator and the control terminals of the first and second transistors.

22. A microcircuit portable device according to claim 17, wherein the first power supply circuit is configured to detect inactive phases between the successive active phases of the first processing circuit and adjust the power supply voltage between power supply and ground terminals of the first processing circuit, as a function of the varying signal during the inactive phases between the successive process phases of the first processing circuit, in response to detecting the inactive phases.