RU2466496C1 - Microchip with microelectromechanical protection from electrical and/or thermal overload - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: microchip with microelectromechanical protection from electrical and/or thermal overload includes at least one semiconductor integrated circuit, at least one movable thermomechanical microactuator, wherein the number of semiconductor integrated circuits is equal to the number of movable thermomechanical microactuators, a structure which is sensitive to external factors, for example: temperature, radiation, heavy charged particles, electromagnetic pulses, etc, comprising the following semiconductor integrated elements: bipolar transistors, MOS structures made in the same process cycle with the semiconductor integrated circuit, lying between pockets and/or regions with electron and hole conductivity.

EFFECT: high reliability of the protected semiconductor integrated circuit, relative simplicity of implementation, high efficiency of protection from external factors with pulsed and continuous action, reduced weight and size.

8 cl, 6 dwg

Description

The invention relates to microelectronics, in particular to nano- and microsystem engineering, and can be used in integrated circuits with protection against electrical and / or thermal overloads.

In the prior art, a protection device of the company "MAXWELL TECHNOLOGIES" (USA) is known, implemented in the form of an HSH-3000 chip (see the MAXWELL catalog). The known device contains a detector of radiation and particles, an amplifier, a timer, a logic device and output stages.

The disadvantages of the known device is the low sensitivity to heavy charged particles and, as a consequence, the low efficiency of the protection of the chip.

The prior art device L.U-SW CL-0004 of the company "Dormer" (Germany), containing a current sensor connected to the inputs of the signal amplifier, the output of which is connected to the input of the voltage comparator. The reference signal for the comparator is the voltage generated by the divider, the output of the comparator through the matching circuit is connected to the R-input of the RS-trigger, the output of the RS-trigger is connected to the control input of the electronic switch, the input of which is connected to the current sensor, and the output is the output of the device.

A disadvantage of the known device is its susceptibility not only to the current component consumed by the protected microcircuit due to its rated current, and to the current component due to the thyristor effect that occurs when a heavy charged particle enters, but also to its sensitivity to the current component due to the total accumulated radiation dose exposure, which has a monotonous nature of the increase, which leads to a deterioration in the sensitivity of the protective device and increase destructive effect on the protected chip. This phenomenon also leads to a significant increase in the delay of the protection, to increase the residence time of the microcircuit in an emergency and, therefore, to reduce reliability. In addition, the known device has insufficient response of the protection when the electronic switch is opened, due to the discharge time of the capacitor connected to the power terminals of the protected microcircuit. The consequence is a low efficiency of protection of the microcircuit and insufficient reliability due to the complexity of the design.

The prior art device for protecting integrated circuits (see the patent of the Russian Federation for invention No. 2305894, publ. 09/10/2007). This device contains a current sensor connected between the input terminal and the electronic switch, the output of which is the output of the device. A current sensor is connected between the first and second inputs of the signal amplifier of the current sensor, the first and second outputs of which are connected to the inputs of a voltage comparator connected to the R-input of the RS-trigger, which has priority over the effect on the R-input. The trigger S input is connected to a high duty cycle pulse generator. The first output of the trigger is connected to the control input of the electronic switch, and the second to the base of a powerful n-p-n transistor, the collector of which is connected to the output of the device, and the emitter is connected to a common bus.

The disadvantage of this device is its complexity, a large number of elements and, as a result, the low reliability of the device.

The prior art device for protecting digital circuits (see patent of the Russian Federation No. 2405247, publ. 11/27/2010), consisting of a measuring resistor installed in the power supply bus of digital circuits, a comparator connected to the input to the measuring resistor, and the output to the source control input power supply of digital microcircuits, boosting transistor, locking diode, timing RC circuit, consisting of a resistor and capacitor, and MIS transistor, while the output of the comparator is connected to the base of the boosting transistor, collect which through a blocking diode is connected to a timing RC circuit and to the gate of an MOS transistor, the drain of which is connected to the control input of the power supply of digital microcircuits.

The disadvantage of this device is the design complexity and, as a result, insufficient reliability during long-term operation.

The technical result of the claimed invention is:

- increase the fault tolerance of a semiconductor integrated circuit;

- improving the reliability of the protected semiconductor integrated circuit;

- relative ease of implementation;

- high efficiency of protection against external influential factors of pulsed and continuous action;

- reduction of overall dimensions.

The technical result of the claimed invention is achieved by a combination of essential features, namely: a microcircuit with microelectromechanical protection against electrical and / or thermal overloads includes:

- at least one semiconductor integrated circuit with a structure that includes semiconductor integrated elements, such as bipolar transistors, MOS - structures that are located between pockets and / or areas with electronic and hole conductivity, each of these elements is sensitive to temperature, radiation, heavily charged particles, an electromagnetic pulse and other external influencing factors, and together these elements form this structure, which is also sensitive to external influencing factors

- at least one movable thermomechanical microactuator, while the number of semiconductor integrated circuits is equal to the number of mobile thermomechanical microactuators,

and a movable thermomechanical microactuator is electrically connected to the structure of a semiconductor integrated circuit sensitive to external factors.

Semiconductor integrated elements: bipolar transistors, MOS - structures are made in a single technological cycle with a semiconductor integrated circuit.

A movable thermomechanical microactuator can be mounted on the housing of the microcircuit with the formation of an electrical contact, while contacting is performed with the formation of a normally closed contact on the power contact of the semiconductor integrated circuit or on the power contact made on the housing or on the surface of the semiconductor integrated circuit in the immediate vicinity of the power contact pad semiconductor integrated circuit, while contacting is performed on the power ring or Well power supply with the formation of a normally closed contact semiconductor integrated circuit.

Movable thermomechanical microactuators are made in the form of an elastic-hinged cantilever beam formed in the mesastructure, consisting of parallel trapezoidal inserts located perpendicular to the main axis of the cantilever beam and connected by polyimide interlayers of a V-shaped or trapezoidal shape in cross section, and a heater with metallization. The structure that is sensitive to external factors is electrically connected with heaters of mobile thermomechanical microactuators. Mobile thermomechanical microactuators are made of at least two layers with different coefficients of thermal expansion, while the coefficient of thermal expansion of the layers of mobile thermomechanical microactuators facing the substrate is greater than the coefficient of thermal expansion of the outer layers of mobile thermomechanical microactuators, while one of the layers of mobile thermomechanical microactuators possesses a reversible shape memory, and mobile thermomechanical microactuators are made in the form of one- or double-beam beam. The heater of a movable thermomechanical microactuator can be made in a mesastructure in a solid body of parallel trapezoidal inserts with ohmic contacts formed in them or located on the surface of parallel trapezoidal inserts.

The features and essence of the claimed invention are explained in the following detailed description, illustrated by drawings, which shows the following:

In Fig.1 (a, b, c) - embodiments of microcircuits with microelectromechanical protection against electrical and / or thermal overloads, where:

1 - movable thermomechanical microactuator;

2 - normally closed power contact of the integrated semiconductor circuit;

2a - normally closed power contact made on the housing;

3 - integrated semiconductor circuit;

4 - microcircuit case;

5 - power contact made on the housing;

6 - ring or power bus integrated semiconductor circuit.

Figure 2 - algorithm of the microcircuit with microelectromechanical protection against electrical and / or thermal overloads, where:

7 - pulsed or continuous external factors affecting the microchip with microelectromechanical protection;

8 - increase in current consumption and / or temperature of the microcircuit with microelectromechanical protection;

9 - external heat source;

10 - heating the movable thermomechanical microactuator;

11 - opening the contact of the movable thermomechanical microactuator and turning off the power of the microcircuit or its part;

12 - reduction of the current consumption and / or temperature of the microelectromechanical protection circuit;

13 - cooling and contact closure of a movable thermomechanical microactuator;

14 - power on the microcircuit with microelectromechanical protection or part thereof.

Figure 3 (a, b) - the influence of external disturbing factors on the deformation characteristics of a movable thermomechanical microactuator. Figa reflects the temperature effect on the movement of a movable thermomechanical microactuator, and Fig.3b shows the movement of a movable thermomechanical microactuator under the action of an electric voltage of a given power.

The principle of operation of the claimed invention is as follows.

The principle of protection of integrated semiconductor circuits against electrical and / or thermal overloads is based on the introduction of a movable thermomechanical microactuator into the power circuit of integrated semiconductor circuits, which is activated (driven) by heating the supply current of the integrated semiconductor circuit.

Under normal conditions, the movable thermomechanical microactuator is closed - the power is supplied to the semiconductor integrated circuit, while the heating of the movable thermomechanical microactuator is negligible.

When a current overload occurs in an integrated semiconductor circuit or when a constant or pulsed action of external factors occurs, a sharp increase in current occurs through a heater of a movable thermomechanical microactuator (for example, due to the occurrence of a thyristor effect), heating of a movable thermomechanical microactuator and opening of contacts of a movable thermomechanical microactuator. Opening the contacts leads to power failure of the integrated semiconductor circuit, turn off the thyristor (in the event of a thyristor effect) and, as a result, to prevent the development of thermal breakdown in the integrated semiconductor circuit.

Mobile thermomechanical microactuator can be installed on:

- the housing of the microcircuit with the formation of an electrical contact, while the contact is made directly to the power contact of the integrated semiconductor circuit (see figa);

- the surface of the integrated semiconductor circuit in the immediate vicinity of the power contact pad of the semiconductor integrated circuit, while contacting is performed on the power ring or power bus of the integrated semiconductor circuit (see figb);

- the housing of the microcircuit in the immediate vicinity of the semiconductor integrated circuit with the formation of electrical contacts with the areas of the housing (option "system in the housing", see figv).

Electrical and / or thermal overloads can occur due to external factors: continuous (constant) and / or pulsed, such as, for example: temperature, radiation, heavily charged particles, electromagnetic pulse, etc.

Protected microcircuits can be, for example: microprocessors, microcontrollers, RAM chips, read only memory chips, ADC and DAC chips, etc.

Implementation example.

The claimed technical solution is used to create VLSI microchips of a reprogrammable non-volatile memory and VLSI microprocessors operating in the temperature range from -60 ° C to + 125 ° C. For these microcircuits, the failure rate was assessed in the presence of microelectromechanical protection and without microelectromechanical protection.

According to the materials of the standard MIL-HDBK-217E (USA), the temperature coefficient π _T , which relates the probability of failure to the VLSI crystal temperature, for silicon products is determined by the formula

where Tj is the temperature of the VLSI crystal,

const is a tabulated constant.

For some thermal operating modes of the VLSI, π _T values and the level of failure reduction (K1 and K2) from the influence of elevated temperatures, numerically equal to the ratio of temperature coefficients for different modes and reflecting the effectiveness of using microelectromechanical protection according to the claimed technical solution, are given in the table:

Table 125 ° C 150 ° C 175 ° C

K1

K2

π _T VLSI memory (const = 0.6) 36 one hundred 250 2.778 6.944 π _T VLSI microprocessors (const = 0.35) 3.1 5.5 9.6 1.774 3.097

For the claimed invention, mobile thermomechanical microactuators were manufactured. Movable thermomechanical actuators have in their structure 30 grooves filled with a polyimide layer, the overall dimensions of the actuator are 300 × 60 × 5 μm. The experimental characteristics of the obtained movable thermomechanical actuators are presented in figure 3.

Figa reflects the temperature effect on the movement of a movable thermomechanical microactuator, and Fig.3b shows the movement of a movable thermomechanical microactuator under the action of an electric voltage of a given power. The experiment also showed that this type of microactuators is able to withstand up to 20 million duty cycles with a slight (up to 20%) and predictable change in deformation characteristics.

The data obtained (see Fig. 3a) make it possible to evaluate the initial installation position of the movable thermomechanical microactuator - 41 μm from the position in the absence of external heating and electric voltage (under normal conditions) in the direction of increasing the load on the clamp of the shank of the movable thermomechanical microactuator to the contact. This position allows the circuit to remain closed up to 125 ° C, since at this temperature, the clamping force of the shank of the movable thermomechanical microactuator to the contact area becomes zero. The power data in FIG. 3b shows that for such circuit to be opened by applying an electrical signal, it is necessary to apply a voltage of minimum power of 23 mW to the heater of the movable thermomechanical microactuator.

The implementation of the claimed technical solution allows using the standard CMOS VLSI technology to increase the stability of microcircuits to single events by 3 times and increase the reliability of the claimed microcircuit.

Claims (8)

1. A microcircuit with microelectromechanical protection against electrical and / or thermal overloads, including:
at least one semiconductor integrated circuit with a structure including semiconductor integrated elements, such as bipolar transistors, MOS structures that are located between pockets and / or areas with electronic and hole conductivity, each of these elements is sensitive to temperature, radiation, heavily charged particles, an electromagnetic pulse and other external influencing factors, and together these elements form this structure, which is also sensitive to external contributing factors
at least one movable thermomechanical microactuator, while the number of semiconductor integrated circuits is equal to the number of mobile thermomechanical microactuators,
and a movable thermomechanical microactuator is electrically connected to the structure of a semiconductor integrated circuit sensitive to external factors. 2. The microcircuit according to claim 1, in which the movable thermomechanical microactuator is mounted on the housing of the semiconductor integrated circuit with the formation of an electrical contact, wherein the contact is made with the formation of a normally closed contact on the power contact of the semiconductor integrated circuit or on the power contact made on the housing. 3. The microcircuit according to claim 1, in which the movable thermomechanical microactuator is mounted on the surface of the semiconductor integrated circuit in the immediate vicinity of the power contact pad of the semiconductor integrated circuit, wherein contacting is performed on the power ring or power bus to form a normally closed contact of the semiconductor integrated circuit. 4. The microcircuit according to claim 2 or 3, in which the movable thermomechanical microactuators are made in the form of an elasto-hinged cantilever beam formed in the mesastructure, consisting of parallel trapezoidal inserts located perpendicular to the main axis of the cantilever beam and connected by polyimide interlayers of a V-shaped or trapezoidal shape in cross section , and a metallized heater. 5. The microcircuit according to claim 4, in which the structure is sensitive to external factors, the semiconductor integrated circuit is electrically connected to the heaters of mobile thermomechanical microactuators. 6. The microcircuit according to claim 5, in which the movable thermomechanical microactuators are made of at least two layers with different coefficients of thermal expansion, the coefficient of thermal expansion of the layers of mobile thermomechanical microactuators facing the substrate is greater than the coefficient of thermal expansion of the outer layers of the mobile thermomechanical microactuators, while one of the layers of mobile thermomechanical microactuators has a reversible shape memory, and mobile thermomechanical microactuators ry formed as a single or dual console beams. 7. The microcircuit according to claim 6, in which the heater of the movable thermomechanical microactuator is made in a mesastructure in a solid body of parallel trapezoidal inserts with ohmic contacts formed in them. 8. The microcircuit according to claim 6, in which the heater of the movable thermomechanical microactuator is located on the surface of parallel trapezoidal inserts.

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