![]() SECURE ELECTRONIC CHIP
专利摘要:
The invention relates to a secure electronic chip (50) comprising a plurality of polarized semiconductor boxes (3, 33) and a detection circuit (57, 61) for the polarization current of the boxes. 公开号:FR3042891A1 申请号:FR1560089 申请日:2015-10-22 公开日:2017-04-28 发明作者:Alexandre Sarafianos;Jimmy Fort;Clement Champeix;Jean-Max Dutertre;Nicolas Borrel 申请人:STMicroelectronics Rousset SAS; IPC主号:
专利说明:
SECURE ELECTRONIC CHIP Field The present application relates to electronic chips, in particular electronic chips secured against attacks. Presentation of the prior art Electronic chips containing confidential information, such as bank card chips, are susceptible to hacker attacks aimed at detecting the operation of the chip and extracting confidential information from it. An attack can be performed on the operating chip connected between the terminals of a power source. One way to achieve such an attack is for a hijacker to scan the surface of the chip with a laser beam that impulsively disrupts the operation of the chip. It is the observation of the consequences of these disturbances, sometimes called faults, on the activity of the circuit, which allows the pirate to carry out his attack. To disrupt the operation of the chip, the hacker can also make contacts on the surface of the chip and apply potentials. The hacker may also have a coil near the surface of the chip to emit electromagnetic interference. It is desirable to have electronic chips protected against this type of attack, said attack by injection of faults, the known devices having various disadvantages and difficulties of implementation. summary Thus, an embodiment provides a secure electronic chip comprising a plurality of polarized semiconductor boxes and a polarization current detection circuit caissons. According to one embodiment, the detection circuit is adapted to produce an alert signal when the bias current is greater, in absolute value, than a threshold. According to one embodiment, the detection circuit comprises a resistive element traversed by the bias current, the detection circuit being adapted to detect a voltage across the resistive element. According to one embodiment, the resistive element has a resistance of between 1 and 100 Q. According to one embodiment, the secure electronic chip comprises a power supply circuit adapted to provide a bias potential of said boxes, the detection circuit being adapted to detect a variation of a potential regulating the polarization potential. According to one embodiment, the supply circuit comprises an operational amplifier whose output is coupled to the gate of a first MOS transistor, and the detection circuit comprises a second MOS transistor forming a current mirror with the first MOS transistor. , an input of the operational amplifier and the drain of the first MOS transistor being coupled to said boxes, and the detection circuit being adapted to detect a variation of the current in the second transistor. According to one embodiment, the plurality of caissons comprises first chambers of a first conductivity type and second caissons of a second conductivity type, the detection circuit comprising on the one hand a first circuit detecting the polarization current. first boxes and secondly a second circuit detecting the bias current of the second boxes. According to one embodiment, the first boxes are formed in the upper part of a semiconductor substrate of the second type of conductivity and the second boxes are upper parts of the substrate between the first boxes. According to one embodiment, the first caissons and the second caissons extend over a doped buried layer of the first conductivity type covering a substrate of the second conductivity type. Another embodiment provides a method of securing an electronic chip comprising a plurality of polarized semiconductor boxes, comprising a step of detecting the polarization current of the boxes. According to one embodiment, the chip contains confidential data, the method comprising, when the detected bias current is greater than a threshold, a step of destroying the confidential data. According to one embodiment, the method comprises, when the detected bias current is greater than a threshold, a step of stopping the activity of the chip. Brief description of the drawings These and other features and advantages will be set forth in detail in the following description of particular embodiments made without implied limitation in relation to the appended figures in which: FIG. 1 is a schematic partial sectional view of an electronic chip of a first type; Figure 2 is a schematic partial sectional view of an electronic chip of a second type; FIG. 3 represents an embodiment of an electronic chip of the first type protected against attacks; FIG. 4 represents an embodiment of an electronic chip of the second type protected against attacks; and Figures 5A and 5B detail embodiments of power and sensing circuits. detailed description The same elements have been designated with the same references in the various figures and, moreover, the various figures are not drawn to scale. For the sake of clarity, only the elements that are useful for understanding the described embodiments have been shown and are detailed. In the following description, when reference is made to relative position qualifiers, such as the term "superior", reference is made to the orientation of the element concerned in the figures. In the present description, the term "connected" refers to a direct electrical connection between two elements, while the term "coupled" refers to an electrical connection between two elements which may be direct or through one or more other components. passive or active, such as resistors, capacitors, inductors, diodes, transistors, etc. FIG. 1 is a schematic partial sectional view of an electronic chip 1 of a first type comprising N-type doped semiconductor casings 3 formed in the upper part of a p-type doped semiconductor substrate 5. For the sake of clarity , only a box and part of another box are shown in Figure 1. N-channel MOS transistors 6 are formed in and on the parts of the substrate located between the caissons 3 and comprise grids 7 and drain and source zones 9 and 11. P-channel MOS transistors 12 are formed in and on boxes 3 and include grids 13 and drain and source areas 15 and 17. The transistors are coupled together to form circuits, for example digital circuits. By way of illustrative example, an inverting logic circuit between nodes 19 and 21 is shown. The digital circuits comprise supply nodes 23 and 25. In the example shown, the supply nodes 23 and 25 are respectively coupled to the sources 11 and 17 of the transistors 6 and 12. The N-type doped caissons 3, or N caissons, are provided with polarization contacts 27 and the substrate is provided with biasing contacts 29. The transistors and polarization contacts are separated by isolation trenches 31. A GND reference potential, for example ground, is applied both to the supply nodes 23 and to the polarization contacts 29 of the boxes P. An unrepresented supply circuit included in the chip provides a potential λ / DD applied both on the supply nodes 25 and on the polarization contacts 27 of the boxes N. In the remainder of the description, in an electronic chip of the first type, box P will be called the upper portions 33 of the substrate between N. FIG. 2 is a schematic partial sectional view of an electronic chip 40 of a second type comprising N 3 wells and P 3 wells extending over an N-type doped buried layer 42 covering a doped type substrate 5; P. The caissons 3 and 33 correspond to the caissons 3 and 33 of the chip 1 described previously, that is to say that they comprise polarization contacts 27 and 29 and digital circuits composed by transistors 6, 12 formed in and on the caissons. The digital circuits are provided with power nodes 23 and 25. The digital circuits are fed between the ground GND and a potential λ / DD respectively applied on the nodes 23 and 25. Polarization potentials λ / PW and λ / NW, which may not be identical to the potentials GND and λ / DD, are applied respectively to the bias contacts 29 and 27, and are provided by unrepresented power supplies included in the chip. As indicated in the preamble, for circuits containing confidential information, an attacker is likely to proceed to an analysis by fault injection. Modes of detection of such attacks are described below. FIG. 3 represents an embodiment of an electronic chip 50 of the first type protected against attacks. Figure 3 comprises a partial sectional view of the chip 50 and a representation of circuits included in this chip. The chip 50 comprises elements of the chip 1 described in relation with FIG. 1 and in particular of the wells N 3 and the wells P 33. Circuits, for example digital circuits, comprise transistors 6 formed in and on the wells P 33 and transistors 12 formed in and on the N-wells 3. The digital circuits have feed nodes 23 and 25 and the wells 3 and 33 are provided with respective bias contacts 27 and 29. The bias contacts and the transistors are separated by isolation trenches 31. The supply nodes 23 of the circuits are coupled to ground. In addition, the chip 50 includes a power supply circuit 52 (VDD) which provides a VDD potential applied to the power supply nodes 25. The power supply circuit 52 is itself powered between a positive VCC potential and a voltage potential. GND mass provided by a power source not shown external to the chip 50. The polarization contacts 29 of the boxes P are not connected directly to ground, but are coupled to ground by a resistive element 54 included in the chip. The voltage at the terminals of the resistive element 54 is compared with a threshold by a comparator circuit 56 adapted to produce an alarm signal AP when this voltage is greater than the threshold. The resistive element 54 and the comparator circuit 56 thus constitute a detection circuit 57 for the bias current of the caissons 33. The polarization contacts 27 of the caissons N are coupled to the supply circuit 52 by a resistive element 58. The voltage across the resistive element 58 is compared to a threshold by a comparator circuit 60 adapted to produce a warning signal AN when this voltage is above the threshold. The resistive element 58 and the comparator circuit 60 thus constitute a detection circuit 61 for the polarization current of the caissons 3. In normal operation, the junctions between the caissons N and the substrate are reverse biased, and no significant bias current flows in the resistive elements 54 and 58. The thresholds mentioned above can therefore be very low. During an attempt to attack the chip by injection of faults, for example at the moment when a pirate bombards the chip by a laser beam, currents UN and IIP appear between the polarization contacts 27 of the wells N 3 and the contacts P bias currents 29. These bias currents UN and IIP are detected by the detection circuits 57 or 61 and cause the transmission of warning signals AN or AP. The signal is used by the chip to take countermeasures such as suspending or stopping its activity or destroying confidential information contained therein. During an attack attempt by a hacker, the IIP and UN currents that result from a disruption of the operation of the chip are analyzed by the chip to detect the attack. The polarization currents UN and IIP used to detect the attack correspond directly to the currents resulting from the disturbance. Thus, the chip detects an injected energy much lower than the minimum fault injection energy. Therefore, the chip 1 is advantageously protected against any attack by injection of faults, whatever the location of the attack on the surface of the chip. For example, the resistors 54 and 58 may be between 1 and 100 Q. Alternatively, the resistive elements 54 and 58 may be components or portions of the chip, for example portions of housings, adapted to produce a voltage at the passage of a current. FIG. 4 represents an embodiment of an electronic chip 70 of the second type protected against attacks. Figure 4 comprises, schematically, a partial sectional view of the chip 70 and a representation of circuits included in this chip. The chip 70 comprises elements of the chip 40 described in relation to FIG. 2 and in particular N 3 wells and P 3 wells extending over an N type doped buried layer 42 covering a P type doped substrate. circuits, for example digital circuits, formed in and on the boxes, have supply nodes 23 and 25. The boxes N 3 are provided with polarization contacts 27 and the boxes P 33 are provided with polarization contacts 29. The feed nodes 23 of the digital circuits are coupled to ground. In addition, the chip 70 includes a power supply circuit 52 which provides a VDD potential applied to the power nodes 25. The biasing contacts 29 of the casings P are coupled to a supply circuit 72 which produces a potential VPW. The supply circuit 72 comprises a detection circuit 73 (DETP) of the bias current supplied to the boxes P. The detection circuit 73 is adapted to produce an AP signal when the bias current is greater, in absolute value, than a threshold. The polarization contacts 27 of the caissons N are coupled to a power supply circuit 74 which produces a bias potential VNW. The supply circuit 74 comprises a detection circuit 75 (DETN) of the bias current supplied to the wells N. The detection circuit 75 is adapted to produce an AN signal when the bias current is greater, in absolute value, than a threshold. The supply circuits 52, 72 and 74 are supplied between potentials VCC and GND provided by a supply device, not shown, outside the chip. In the case of a fault injection attack, the detection by the chip 70 is similar to the detection by the chip 50 of FIG. 3. The bias currents II detected by the chip are separated from the power supply currents 12. normal activity of the chip. In the embodiment of the chip 70, the bias potentials VNW and VPW may be different from the supply potentials VDD and GND, for example to accelerate the operation of the chip, or to reduce its consumption. FIG. 5A details an embodiment of a power supply circuit 74 coupled to a polarization contact 27 of a box N. The supply circuit 74 comprises an operational amplifier 80 whose output is coupled to the gate G1 of FIG. A P-channel MOS type PMI transistor. Two series-connected resistors RI and R2 couple the drain PMI of the PMI to ground, the common node between the resistors being coupled to the positive input of the amplifier 80. Controlled potential V0 is applied to the negative input of the amplifier 80. The amplifier 80 is supplied between the ground GND and an application node of a potential VCC provided by an external power supply device. The source S1 of the PMI transistor is coupled to the potential VCC. The bias contacts 27 are coupled to the drain D1. The detection circuit 75 of the supply circuit 74 comprises two P-channel MOS type PM2 and PM3 transistors, forming current mirrors with the PMI transistor, that is to say whose gates G2 and G3 are coupled with the gate G1 and the sources D2 and D3 are coupled to the source S1. The drain D2 of the transistor PM2 is coupled to ground by a current source which draws a current 13+ on the drain D2. The drain D3 of the transistor PM3 is coupled to ground by a current source which draws a current 13- on the drain D3, the current 13 being lower than the current 13+. An inverter 82 couples the drain D3 to an input of an OR gate 84 whose other input is coupled to the drain D2. Activation of the output of the gate 84 produces the AN signal. When the circuit 74 operates, a current 13 flows in the resistors R1 and R2, the current 13 being chosen to be between the currents 13+ and 13-. This current is added to the bias current II in the PMI transistor, and a current equal to II + 13 flows in each of the PM2 and PM3 transistors. In normal operation, the current 15 is between the currents 13- and I3 +, and the output AN is deactivated. In the event of an attack attempt, as soon as the current 15 leaves the interval between 13- and 13 +, the drain potential D2 increases or the drain potential D3 decreases, and the output AN is activated. In other words, the appearance of a current It causes a variation of the potential supplied by the amplifier 80 which regulates the voltage supplied by the supply circuit 74, and the detection circuit 75 identifies this variation of potential to detect the current II. As a variant, the detection circuit 75 may be replaced by any circuit adapted to detect a variation of a regulation potential of a supply circuit. The difference between the currents 13 and 13 corresponds to the detection threshold of a current II coming from the polarization contact 27 and the difference between the currents 13 and 13+ corresponds to the detection threshold of a current II flowing towards the contact of polarization 27. By way of example, the detection thresholds are between 0.2 and 2 mA. FIG. 5B details an embodiment of a supply circuit 72 coupled to a contact 29 for biasing an N. box. The supply circuit 72 corresponds to the power supply circuit 74 of FIG. 5A, in which the resistors R1 and R2 have been replaced by series resistors R3 and R4 completing the drain DI to a supply circuit 86, the node common between the resistors R3 and R4 being coupled to the positive input of the amplifier 80. By way of example, the detection circuits 73 and 75 are similar. The supply circuit 86 produces a potential lower than the potential of the mass, from the positive potential VCC and ground. The circuit 86 may be a clock synchronized charge pump circuit (CLK). As a variant, the detection circuit 73 may be replaced by a detection circuit adapted to detect a variation of a regulation potential of the circuit 86. Particular embodiments have been described. Various variations and modifications will be apparent to those skilled in the art. In particular, although in the embodiments described, the bias currents of the wells P 33 and the bias currents of the wells N 3 are simultaneously monitored by two detection circuits, variants are possible in which the bias current of the wells only one type of conductivity is monitored by a single detection circuit. Furthermore, although in the embodiments described, the secure chips comprise digital circuits comprising MOS transistors 6 and 12, identically protected chips may also include analog circuits, for example comprising components such as bipolar transistors. , resistors or diodes, the important thing is that the chip has polarized boxes. In addition, although in the described embodiments a P-type doped substrate has been provided, variants are possible in which the substrate 5 is replaced by an N-type doped substrate or a silicon-type substrate on the substrate. insulation, or by a support in another semiconductor. In addition, although particular detection circuits have been detailed in the embodiments described, other detection circuits adapted to detect a bias current are possible. Various embodiments with various variants have been described above. It will be appreciated that those skilled in the art may combine various elements of these various embodiments and variants without demonstrating inventive step. In particular, each of the detection circuits 73 and 75 of the embodiment of a secure chip of the second type can replace one or the other of the detection circuits 57 and 61 of the embodiment of a secure chip of the first type. In addition, embodiments adapted to integrated circuit chips of a first type and a second type have been described. What has been described obviously applies to other types of integrated circuit technology, including various types of boxes.
权利要求:
Claims (12) [1" id="c-fr-0001] A secure electronic chip (50; 70) comprising a plurality of polarized semiconductor boxes (3,33) and a detection circuit (57,61,73,75) of the box bias current. [2" id="c-fr-0002] 2. An electronic chip according to claim 1, wherein the detection circuit (57, 61; 73, 75) is adapted to produce an alarm signal (AN, AP) when the bias current is greater, in absolute value, at a threshold. [3" id="c-fr-0003] Electronic chip (50) according to claim 1 or 2, wherein the detection circuit (57, 61) comprises a resistive element traversed by the bias current, the detection circuit being adapted to detect a voltage across the terminals of the resistive element. [4" id="c-fr-0004] An electronic chip according to claim 3, wherein the resistive element (54, 58) has a resistance of between 1 and 100 Q. [5" id="c-fr-0005] 5. The electronic chip (70) according to any one of claims 1 to 4, comprising a power supply circuit (72, 74) adapted to provide a bias potential of said boxes (3, 33), the detection circuit (73, 73). , 75) being adapted to detect a variation of a potential regulating the polarization potential. [6" id="c-fr-0006] An electronic chip according to claim 5, wherein the power supply circuit (72, 74) comprises an operational amplifier (80) whose output is coupled to the gate of a first MOS transistor (PMI), and wherein the detection circuit (73, 75) comprises a second MOS transistor (PM2) forming a current mirror with the first MOS transistor, an input of the operational amplifier and the drain of the first MOS transistor being coupled to said subwoofers (3, 33 ), and the detection circuit being adapted to detect a variation of the current in the second transistor. [7" id="c-fr-0007] 7. An electronic chip (50; 70) according to any one of claims 1 to 6, wherein the plurality of boxes comprises first boxes of a first conductivity type and second boxes of a second type of conductivity, the detection circuit comprising firstly a first circuit detecting the bias current of the first boxes and secondly a second circuit detecting the bias current of the second boxes. [8" id="c-fr-0008] An electronic chip (50) according to claim 7, wherein the first wells are formed in the upper portion of a semiconductor substrate (5) of the second conductivity type and the second wells are upper portions of the substrate between the first caissons. [9" id="c-fr-0009] 9. The electronic chip (70) according to claim 7, wherein the first boxes and the second boxes extend over a buried layer (42) doped with the first type of conductivity covering a substrate (5) of the second conductivity type. [10" id="c-fr-0010] 10. A method of securing an electronic chip comprising a plurality of polarized semiconductor boxes, comprising a step of detecting the polarization current of the boxes. [11" id="c-fr-0011] 11. Securing method according to claim 10, wherein the chip contains confidential data, the method comprising, when the detected bias current is greater than a threshold, a step of destroying the confidential data. [12" id="c-fr-0012] 12. Securing method according to claim 10 or 11, comprising, when the bias current detected is greater than a threshold, a step of stopping the activity of the chip.
类似技术:
公开号 | 公开日 | 专利标题 EP3159872A1|2017-04-26|Multiple-well technology for secure electronic chip EP3236496A1|2017-10-25|Electronic chip with backside attack protection FR2752335A1|1998-02-13|INTEGRATED CIRCUIT INCORPORATING A CIRCUIT FOR DRIVING MOUNTED POWER TRANSISTORS ACCORDING TO A HALF-BRIDGE CONFIGURATION ALLOWING EXCESSIVE NEGATIVE OSCILLATION OF THE OUTPUT NODE EP2702363B1|2015-01-07|Integrated circuit for capacitive measurement including a floating bridge EP3151277A1|2017-04-05|Secure integrated circuit EP2535932A1|2012-12-19|Integrated circuit chip comprising protecting means against attacks FR2981783A1|2013-04-26|System for detecting laser attack of integrated circuit chip in semiconductor substrate, has resistor and comparator for detecting potential variations of substrate, where resistor has terminal connected to potential detection contacts US20130314121A1|2013-11-28|Method and device for protecting an integrated circuit against backside attacks EP2355152A1|2011-08-10|Integrated circuit with protection against electrostatic discharges FR2986633A1|2013-08-09|DEVICE FOR DETECTION OF LASER ATTACK IN AN INTEGRATED CIRCUIT CHIP EP3301605B1|2021-03-31|Protected electronic chip EP2535933A1|2012-12-19|Integrated circuit chip comprising protecting means against attacks WO2017203187A1|2017-11-30|Integrated circuit comprising a plurality of chips formed by a high-voltage transistor and comprising a chip formed by a low-voltage transistor EP1400887A1|2004-03-24|Protecting device for electronic chip containing confidential data WO2018162805A1|2018-09-13|Electronic chip EP3343427B1|2020-09-30|Method and device for managing the power consumption of an integrated module FR2958078A1|2011-09-30|Method for detecting fault-injection error attack within electronic microcircuit of smart card, involves activating detection signals when voltages at mass and supply terminals exceed threshold voltages US10998276B2|2021-05-04|Integrated circuit FR3070092A1|2019-02-15|PROTECTION OF AN INTEGRATED CIRCUIT EP3483773B1|2020-07-08|Method for randomly modifying the consumption profile of a logic circuit, and associated device FR3000815B1|2019-10-11|POWER REGULATOR OF AN INTEGRATED CIRCUIT FR3112004A1|2021-12-31|Detection of an electromagnetic pulse FR3053833A1|2018-01-12|INTEGRATED CIRCUIT COMPRISING A FORMED CHIP OF A HIGH VOLTAGE TRANSISTOR COMPRISING A SHAPED CHIP OF A LOW VOLTAGE TRANSISTOR EP3961344A1|2022-03-02|Power supply for electronic circuit EP3570200A1|2019-11-20|Electronic chip
同族专利:
公开号 | 公开日 US10691840B2|2020-06-23| CN106611209B|2020-08-11| EP3159872B1|2021-08-11| US20170116439A1|2017-04-27| CN205621041U|2016-10-05| EP3159872A1|2017-04-26| CN111783920A|2020-10-16| CN106611209A|2017-05-03| FR3042891B1|2018-03-23|
引用文献:
公开号 | 申请日 | 公开日 | 申请人 | 专利标题 FR2981783A1|2011-10-19|2013-04-26|St Microelectronics Rousset|System for detecting laser attack of integrated circuit chip in semiconductor substrate, has resistor and comparator for detecting potential variations of substrate, where resistor has terminal connected to potential detection contacts| FR2986633A1|2012-02-08|2013-08-09|St Microelectronics Rousset|DEVICE FOR DETECTION OF LASER ATTACK IN AN INTEGRATED CIRCUIT CHIP| US7847581B2|2008-04-03|2010-12-07|Stmicroelectronics Sas|Device for protecting an integrated circuit against a laser attack| CN103383736A|2012-05-02|2013-11-06|中频电子股份有限公司|Method for verifying electronic chip and user terminal| FR3042891B1|2015-10-22|2018-03-23|Stmicroelectronics Sas|SECURE ELECTRONIC CHIP|FR3042891B1|2015-10-22|2018-03-23|StmicroelectronicsSas|SECURE ELECTRONIC CHIP| FR3050317A1|2016-04-19|2017-10-20|StmicroelectronicsSas|MICROCHIP| FR3062952B1|2017-02-13|2019-03-29|StmicroelectronicsSas|DECOUPLING CAPACITOR| FR3070092A1|2017-08-11|2019-02-15|StmicroelectronicsSas|PROTECTION OF AN INTEGRATED CIRCUIT| FR3072211B1|2017-10-11|2021-12-10|St Microelectronics Rousset|METHOD OF DETECTION OF AN INJECTION OF FAULTS AND THINNING OF THE SUBSTRATE IN AN INTEGRATED CIRCUIT, AND ASSOCIATED INTEGRATED CIRCUIT| US10306753B1|2018-02-22|2019-05-28|International Business Machines Corporation|Enclosure-to-board interface with tamper-detect circuit| US11122682B2|2018-04-04|2021-09-14|International Business Machines Corporation|Tamper-respondent sensors with liquid crystal polymer layers| FR3081240B1|2018-05-15|2021-08-06|St Microelectronics Rousset|MICROCHIP| FR3083919A1|2018-07-13|2020-01-17|StmicroelectronicsSas|PROTECTED ELECTRONIC CHIP|
法律状态:
2016-09-21| PLFP| Fee payment|Year of fee payment: 2 | 2017-04-28| PLSC| Publication of the preliminary search report|Effective date: 20170428 | 2017-09-21| PLFP| Fee payment|Year of fee payment: 3 | 2018-09-19| PLFP| Fee payment|Year of fee payment: 4 | 2020-10-16| ST| Notification of lapse|Effective date: 20200906 |
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申请号 | 申请日 | 专利标题 FR1560089|2015-10-22| FR1560089A|FR3042891B1|2015-10-22|2015-10-22|SECURE ELECTRONIC CHIP|FR1560089A| FR3042891B1|2015-10-22|2015-10-22|SECURE ELECTRONIC CHIP| EP16161366.6A| EP3159872B1|2015-10-22|2016-03-21|Multiple-well technology for secure electronic chip| CN202010608733.9A| CN111783920A|2015-10-22|2016-04-25|Secure electronic chip| US15/137,789| US10691840B2|2015-10-22|2016-04-25|Secure electronic chip| CN201610352606.0A| CN106611209B|2015-10-22|2016-04-25|Secure electronic chip| CN201620482834.5U| CN205621041U|2015-10-22|2016-04-25|Safe electron chip| 相关专利
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