JP4617732B2 - Mechanical quantity measuring device - Google Patents

Description

  The present invention relates to a mechanical quantity measuring device that measures a mechanical quantity.

  A tag, called an RF tag, that operates by using power supplied by electromagnetic induction and transmits a preset ID number via radio waves has been developed and is applied to logistics management and admission ticket management. I'm starting. Attempts have been made to connect a physical quantity sensor to such an ID tag and transmit the sensed value wirelessly. For example, as seen in Japanese Patent Application Laid-Open No. 2001-187611, a temperature sensor is connected to an RF tag circuit on a printed wiring board, and the ID tag with a sensor is integrally molded with plastic while mounted on the printed wiring board. It is configured as. Japanese Patent Application Laid-Open Nos. 05-203682 and 09-264798 disclose sensors in which a circuit is formed on a semiconductor substrate.

JP 2001-187611 A Japanese Patent Laid-Open No. 05-203682 JP 09-264798 A

  However, a strain sensor or a mechanical quantity sensor such as a pressure sensor, vibration sensor, or acceleration sensor is connected to a circuit that operates by using electric power supplied by electromagnetic induction or microwaves and transmits the result. Attempts to occur the following problems specific to the mechanical quantity sensor. In addition, since various environmental influences are received under use conditions, a sensor capable of highly accurate measurement under such conditions is desired. In the known technique, there is no specific disclosure about a form for performing high-precision measurement.

First, the strain sensor has a very small output value with respect to the strain, and is very sensitive to noise compared to other temperature sensors. For example, a resolution of about 10 ⁻⁵ strain is required for normal use, but the resistance change (ΔR / R) at that time in the most frequently used resistance wire strain gauge is about 2 × 10 ⁻⁵ . That is, it must be detected that the resistance which was 1 at no strain is strained and becomes 1.00002. At this time, there is a risk that a large measurement error may occur due to noise. In particular, when an operation is attempted by using electric power supplied by electromagnetic induction or microwaves, noise is likely to be picked up because the strain sensor also receives radio waves at the same time. In addition, when using electric power supplied by electromagnetic induction or microwave, the amount of power that can be supplied to the strain sensor is very limited, and it is more than two orders of magnitude compared to the case of using strain gauges and amplifiers that are generally commercially available. It needs to be small. For this reason, if the value of the current flowing through the strain sensor is suppressed to 200 μA or less, it is easily affected by noise and may be buried in substantial noise. Further, strain measurement is often performed by directly bonding a sensor to an object to be measured, and considering this use state, it is difficult to completely shield the sensor and its lead wire with a conductor and completely shield it. In addition, when performing normal strain measurement, it is required to measure the amount of strain in a specific direction for a measurement object whose strain is not known, so a strain sensor that can accurately detect the amount of strain in a specific direction is also available. Desired.

  Therefore, an object of the present patent is to provide a mechanical quantity measuring apparatus that can solve at least one of the above-described problems and enables highly accurate measurement.

The present invention has a strain detection unit formed on a single crystal semiconductor substrate, and in the mechanical quantity measuring device attached to or embedded in the measurement object to measure the strain of the measurement object, the strain detection unit A Wheatstone bridge circuit having a pair of sensor resistance layers and a pair of dummy resistance layers formed on one main surface of a single crystal semiconductor substrate, and each sensor resistance layer and dummy resistance layer having substantially the same resistance value. And a plurality of second resistance layers that are formed along the longitudinal direction of each sensor resistance layer and dummy resistance layer and do not constitute the Wheatstone bridge circuit. It is characterized by connection.

  According to the present invention, a mechanical quantity measuring apparatus that can solve one of the problems can be configured. For example, even when circuit operating power is supplied by electromagnetic induction or microwaves, it is possible to provide a mechanical quantity measuring device that is not easily affected by noise and enables highly accurate measurement.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows a mechanical measurement device 1 used in the present invention. The mechanical measurement device 1 shows an example in which a single crystal silicon substrate 2 is used as an example of a semiconductor substrate. A strain sensor 3 using at least a piezoresistive effect on this substrate, an amplifier group 4 for amplifying a voltage value obtained from the strain sensor 3, an analog / digital converter 5, a rectification / detection / modulation / demodulation circuit unit 6, a communication control unit 7, an adhesive portion 8, an antenna 9, and a power supply device 10. Here, the power supply apparatus 10 may be a battery such as a storage battery or a solar battery, or may be a power generation apparatus using vibration power generation, a piezoelectric effect, or the like. In particular, in this embodiment, the driving power source of the mechanical quantity measuring device 1 is an induced electromotive force generated by the electromagnetic wave supplied from the reader antenna 202 in the reader 201 provided outside as shown in FIG. Hereinafter, the silicon substrate 2 and the thin film group formed on the substrate are collectively referred to as a chip 101. The antenna 9 increases the number of turns of the antenna, and further increases the area surrounded by the antenna, so that the amount of magnetic flux passing through the antenna can be increased and a large amount of electric power can be generated. . For this reason, the antenna 9 may be provided outside the chip 101. Hereinafter, a case where the antenna 9 is built in the chip 101 will be described as an example. When the antenna 9 is built-in, the chip 101 corresponds to the mechanical quantity measuring device 1, and when the antenna 9 is externally attached, the chip 101 and the antenna 9 are collectively referred to as the mechanical quantity measuring device 1. When an antenna is built in the chip 101, an electrode pad for external connection becomes unnecessary, so that the electrode is not exposed to the chip surface, and the electrode pad does not corrode even when used in a poor environment. The generation of unnecessary noise on the wiring between the chip and the antenna can be suppressed as much as possible. In addition, it is desirable in terms of reliability because there is no need to worry about electrostatic breakdown when handling the chip. Further, by incorporating the antenna in the chip 101, there is no increase in the wiring length and the resistance value due to the oxide layer formed on the pad, and the power consumption between the communication control unit 7 and the antenna 9 is reduced. Therefore, it is very advantageous when the power supply amount is limited as in the mechanical quantity measuring device 1. Looking at the main surface on which the circuit is formed, the transmission circuit is arranged closer to the silicon substrate end than the strain sensor. Alternatively, the strain sensor is disposed closer to the center of the silicon substrate than other circuits.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows an outline of the structure of the mechanical quantity measuring apparatus according to the first embodiment of the present invention. In order to detect the strain amount of the object to be measured using the mechanical quantity measuring device 1, an adhesive portion 8 which is a surface facing the element forming surface of the chip 101 is attached to the object 11 as shown in FIG. Then, the amount of strain generated in the object to be measured 11 is transmitted to the silicon substrate 2 and converted into an amount of electricity using the strain sensor 3 on the chip 101. When the bonding portion 8 is directly attached to the measurement object 11, neither the silicon substrate nor the measurement object requires special processing, and therefore the attachment of the mechanical quantity measuring device 1 and the strain measurement are facilitated. Further, when the temperature rises while being adhered to the object to be measured 11, a large thermal stress may be generated between the chip 101 and the object to be measured 11. Since the mechanical quantity measuring device 1 is manufactured using a semiconductor process based on photolithography technology, the thin film group including the strain sensor 3 is formed on the upper surface of the silicon substrate. In the present invention, the bonding portion 8 is arranged on the back surface of the silicon substrate 2, and the back surface of the silicon substrate has higher adhesive strength and breaking strength than the upper surface of the chip made of glass or the like. Even when it rises, there is an advantage that reliable measurement can be performed without causing breakage or peeling at the bonded portion 8. This bonding portion 8 has a structure in which the back surface of silicon is roughened, and the size of the unevenness is 1 micron or more in roughness, which is larger than the unevenness on the chip surface. As a result, the anchor effect due to the unevenness is generated, and there is an advantage that the adhesion to the DUT 11 is further improved. The strain sensor 3 is formed by a diffused resistor in which an impurity is implanted into a silicon single crystal. When a strain is applied, the resistance value changes due to a piezoresistive effect. The change in the output voltage amount accompanying the change in resistance value is converted into a digital signal through the strain sensor amplifier group 4 and the analog / digital converter 5. The digital signal is converted into a radio wave signal through the communication control unit 7 and the rectifying / detecting / modulating / demodulating circuit unit 8 and transmitted from the antenna 9 to the reader. When supplying power by induced electromotive force, a high-frequency signal for power sent from a reader is received by an antenna 9, smoothed by a rectifying / detecting / modulating / demodulating circuit unit 7, and converted into DC power of a constant voltage, a mechanical quantity measuring device The power is supplied to each circuit.

  Further, in this case, in order to generate a large amount of electric power by the induced electromotive force, the antenna 9 needs to pass a large amount of magnetic flux through the region surrounded by the antenna. It is desirable to arrange along. By the way, when the back surface of the silicon substrate 2 is an adhesive surface, the larger the ratio of the thickness to the length in the lateral direction of the silicon substrate, the smaller the amount of strain transmitted from the non-measurement object to the upper surface of the silicon substrate. That is, since the strain sensor 3 is located on the upper surface of the silicon substrate 2, the sensitivity of the mechanical quantity measuring device 1 greatly decreases as the ratio of the thickness to the length in the lateral direction of the silicon substrate increases. Therefore, the substrate thickness with respect to the substrate length in the strain measuring direction is reduced. The direction indicated by the arrow in FIG. 3 is the strain measurement direction. For the main side formed at the end of the main surface of the silicon substrate on which the circuit is formed, the main side located in the direction near the strain measuring direction of the strain sensor is another main side located in the direction intersecting the main side. It is at least longer than the side. Alternatively, the strain measurement direction of the strain sensor is formed in a direction along the longitudinal direction of the main surface of the silicon substrate (the strain measurement direction is closer to the longitudinal direction than the direction in which the longitudinal direction intersects).

Alternatively, the ratio of the thickness of the silicon substrate to the length of the semiconductor substrate in the strain measuring direction is 0.3 or less. Alternatively, the ratio of the silicon substrate length and the thickness of the silicon substrate in the direction not giving strain sensitivity is 0.3 or less. Specifically, when the length of the silicon substrate 2 in the strain measuring direction is L ₁ and the thickness of the silicon substrate 2 is t, according to the analysis conducted by the inventors, t / L ₁ is 0.3 or more. In this case, the strain amount transmitted to the upper surface of the silicon substrate 2 was found to be 10% or less with respect to the strain amount generated in the measurement object 11. In general, the range of strain required for strain measurement of structures is on the order of 10 ⁻⁶ to 10 ⁻¹ , and the sensitivity of strain sensors fabricated with silicon diffusion resistors is on the order of 10 ^−7. Therefore, in order to perform strain measurement with high measurement accuracy, it is desirable that the ratio t / L ₁ of the thickness t of the chip 101 and the length L ₁ of the chip 101 in the strain measurement direction is 0.3 or less. . Furthermore, the analysis results revealed that the strain sensitivity showed the maximum value at the center of the upper surface of the silicon substrate 2, and the strain sensitivity decreased as approaching the end. For this reason, the strain sensor 3 is disposed near the center of the upper surface of the silicon substrate 2 having higher sensitivity than other circuits. For example, the circuit is arranged closer to the end of the chip than the strain sensor. You may make it have the area | region where an antenna is arrange | positioned to the edge part side from a circuit. At this time, it can arrange | position so that the antenna part may surround the circumference | surroundings of a strain sensor. By these, it is possible to provide a mechanical quantity measuring device with high sensitivity to strain.

  Circuits such as the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, the communication control unit 7, and the power supply device 10 are also formed on the upper surface of the silicon substrate, and may be affected by the distortion similarly to the strain sensor 3. There is concern, in this case, the accuracy may be reduced. For example, the operational amplifier 4 is composed of a plurality of diffused resistors. When the operational amplifier 4 is affected by distortion, the resistance value changes in the same manner as the strain sensor 3, so that the amplification degree of the operational amplifier 4 may change. Further, the analog / digital converter 5, the rectifying / detecting / modulating / demodulating circuit unit 6, the communication control unit 7, the power supply device 10 and the like may be affected by distortion, and the distortion is highly accurate and reliable. In order to perform the quantity measurement, it is desirable that circuits other than the strain sensor 3 are not affected by the strain as much as possible. Therefore, the strain sensor 3 for measuring the strain amount is disposed in the vicinity of the center of the upper surface of the silicon substrate 2 having the highest sensitivity, and the circuit other than the strain sensor 3 that should eliminate the influence of the strain as much as possible is disposed in the vicinity of the upper surface of the chip. To do. In particular, when the operational amplifier 4 which is an analog circuit and is constituted by an impurity diffusion layer is affected by distortion, the output is greatly affected. Further, since the output from the strain sensor 3 is immediately amplified by the operational amplifier 4, the operational amplifier 3 is adjacent to the strain sensor 3 provided near the center of the upper surface of the silicon substrate 2. It is preferable that other circuits other than the sensor are closer to the outside. It is desirable to dispose at least a region closer to the outer edge of the upper surface of the silicon substrate 2 than the strain sensor 3. Thereby, a highly reliable mechanical quantity measuring device can be provided. Here, the strain sensor 3 is not necessarily arranged accurately in the center of the upper surface of the silicon substrate 2, and an analog / digital converter 5, a rectification / detection / modulation / demodulation circuit unit 6, a communication control unit 7, a power supply device 10, and the like. What is necessary is just to arrange | position to the area | region close | similar to the center of the upper surface of the silicon substrate 2 with respect to this circuit. Further, the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, the communication control unit 7, the power supply device 10 and the like do not necessarily have to be arranged in contact with the end of the upper surface of the chip 101. What is necessary is just to be arrange | positioned in the part near an edge part compared with 3. FIG.

When measuring the amount of strain, measurement of strain components in a specific direction is often required. However, in the measurement object 11, when a plurality of strains in different directions are mixed, the output obtained by the strain sensor 3 includes the influence from the strains in the plurality of directions. In order to measure a strain amount limited to a specific direction, a strain measuring device having strain sensitivity in a specific direction is required. As described above, when the bonding portion 8, which is a surface facing the element formation surface of the chip 101, is attached to the measurement object, the sensitivity of the strain sensor 3 is greatly influenced by the ratio of the length and thickness of the silicon substrate. Therefore, as shown in FIG. 3, the ratio t / L ₁ between the thickness of the silicon substrate 2 and the length of the silicon substrate 2 in the strain measurement direction is set to 0.3 or less, and t in the direction perpendicular to the strain measurement direction is set. / L _{2 is set} to 0.3 or more. Thereby, the mechanical quantity measuring apparatus which has a sensitivity to the strain quantity of the specific direction aiming at strain measurement can be provided. Even in this case, circuits such as the operational amplifier group 4, the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, and the communication control unit 7 are arranged in a region near the upper end of the silicon substrate 2 that is not easily affected by distortion. This makes it possible to perform highly accurate and highly reliable measurement in which the strain measurement direction is limited to a specific direction.

  On the top surface of the chip 101, circuits such as an analog / digital converter 5, a rectification / detection / modulation / demodulation circuit unit 6, a communication control unit 7, and a power supply device 10 are exposed.

  Therefore, as shown in FIG. 4, the protective material 12 is disposed on the upper surface of the chip 101 on which the circuit is formed. By disposing a protective material such as a resin on the upper surface of the silicon substrate 2, the circuit can be protected from external impact or corrosion, and strength reliability can be ensured. Further, when the protective material 12 has a light shielding property, the thin film group disposed on the upper surface of the chip 101 is shielded from the outside. Since the mobility of the electrons moving in the impurity diffusion layer forming the circuit such as the strain sensor 3 is greatly affected by the influence of light, when the light hits, the amount of distortion actually generated is accurately detected. I cannot get the correct output. When the impurity diffusion layer is shielded by using the protective material 12 having a light shielding property, the change in electron mobility due to the influence of light in the strain sensor 3 can be eliminated. Therefore, highly accurate and reliable strain measurement can be performed. It can be carried out. Further, the protective material 12 may be arranged so as not to cover the antenna 9 as shown in FIG. A resin film covering a circuit formed on the substrate is provided, and an end portion of the resin film is located between the region where the antenna 9 is formed. In this case, since there is no inclusion between the antenna 9 and the reader, transmission of radio waves is facilitated, and communication accuracy is improved.

  Further, as shown in FIG. 5 (1), a covering material member is provided to cover the silicon substrate, and a part is in contact with the side surface of the semiconductor substrate, and the other part is in contact with the object to be measured. Here, the protective member 13 can be used as the covering member. The protective material 13 does not necessarily have to cover the entire silicon substrate. The protective material 13 may cover the entire surface including the side surface of the chip 101. It is preferable that one of the protective materials 13 is in contact with the chip 101 and is also in contact with the object to be measured 11. In this case, since the side surface direction of the chip 101 is constrained by the resin 13, the response of the chip 101 to the strain generated in the object to be measured 11 is improved, and the accuracy is improved.

  In order to attach the mechanical quantity measuring device 1 to the object to be measured and measure the amount of strain generated in the object to be measured with high accuracy, there is an attachment method in which the strain responsiveness of the chip 101 to the strain amount of the object to be measured is improved. desired. That is, the silicon substrate 2 constituting the mechanical quantity measuring device 1 is required to perform deformation that accurately follows the amount of strain generated in the object to be measured.

  Therefore, as shown in FIG. 5 (2), the mechanical quantity measuring device 1 is directly embedded in the measuring object 11 using the bonding / fixing inclusion 13. The chip 101 is formed on the side surface of the silicon substrate so as to have a region where a part of the object to be measured is opposed to the chip 101 in a state where the chip 101 is installed on the object to be measured. The mechanical quantity measuring device 1 does not hinder measurement even if it is embedded when strain amount information can be exchanged with the reader in a wireless format. In addition, the mechanical quantity measuring device 1 according to the present invention has a very small side or thickness of several millimeters or less, so that even when a recessed portion for embedding is formed in a non-measurement object, the strength of the measurement object is reduced. Is not invited. As shown in FIG. 7, when the mechanical quantity measuring device 1 is directly embedded in the measurement object 11, not only the adhesion surface 8 but also the side surface and the upper surface of the chip 101 are simultaneously restrained. 11 is improved in the strain response of the chip 101 with respect to the amount of strain generated in 11, and the measurement sensitivity is improved. Further, the mechanical quantity measuring device 1 is blocked from the outside world by being embedded in the measuring object 11. For this reason, the mechanical quantity measuring device 1 can be protected and ensure reliability even in an environment where physical contact or friction from the outside occurs in a strain measurement location, or in a corrosive environment. Can do. In addition, when an inclusion / fixing inclusion with light-shielding properties is used, a change in mobility of electrons and holes in the diffused resistor due to the influence of light can be suppressed, resulting in malfunction. Therefore, a highly accurate mechanical quantity measuring device can be provided. Further, when using, for example, a resin as the inclusion / fixing inclusion resin, the Young's modulus of the resin is about 10 to 20 GPa, while the Young's modulus of the silicon substrate 2 serving as the substrate of the chip 101 is about a few tens of GPa, When the object to be measured 11 is, for example, an iron-based metal, the pressure is about 200 GPa. Therefore, strain relaxation occurs in the resin portion, and sensitivity is lowered. For this reason, the thinner the gap between the tip and the measurement object, the more the sensitivity can be reduced, and the gap is preferably 1 mm or less.

  Further, as shown in FIG. 5 (3), the upper surface of the mechanical quantity measuring device 1 is exposed to the outside, or the antenna portion on the upper surface of the silicon substrate is exposed to the measurement object using an adhesive / fixing inclusion. It can be embedded and measured in the state. Alternatively, as shown in FIG. 5 (4), a part of the mechanical quantity measuring device 1 may be embedded. A silicon substrate is placed in the recess of the member to be measured, and is positioned so that at least a part of the side wall of the substrate faces the side wall of the recess. Alternatively, the silicon substrate is disposed such that the upper surface side of the silicon substrate is positioned higher than the surface of the member to be measured around the region where the silicon substrate is installed, and the lower surface side of the silicon substrate is lower than the surface.

  Even in such a form, since the side surface of the chip 101 is constrained, a higher strain sensitivity can be obtained than when only the bonding surface 8 is bonded. When the top surface of the chip is exposed, the antenna 9 is exposed to the outside, so that there is no interference with radio waves, so that the measurement accuracy is improved and the radio radio wave reach distance is also increased. Even if it is placed in a different location, strain measurement is possible. When only the upper surface of the mechanical quantity measuring device 1 is exposed to the outside as shown in FIG. 5 (3), the surface shape of the object to be measured is not different from that before embedding. If it is a rotating body, it will not interfere with the rotational movement.

  In addition, when a part of the mechanical quantity measuring device 1 is embedded as shown in FIG. 5 (4), when inserting an adhesive / fixing inclusion around the periphery, it does not flow into the upper surface of the mechanical quantity measuring device 1, The antenna 9 arranged on the upper surface of the mechanical quantity measuring device 1 is not covered with the mechanical quantity measuring device 1 and enables stable communication.

The silicon substrate 2 constituting the chip 101 is a silicon single crystal. Since the fracture stress of a silicon single crystal is about 400 MPa at the maximum, considering the Young's modulus of 130 to 160 GPa of the silicon single crystal, the silicon single crystal has a strain of about 2.5 to 3.0 × 10 ^−2. Will be destroyed. However, in a normal strain measurement, a measurement range of about 10 ⁻¹ may be required, which exceeds the critical strain amount of the silicon substrate 2 by one digit. In this case, a resin stress relaxation layer 56 having a Young's modulus smaller than that of the silicon single crystal is provided between the chip 101 and the DUT 11 as shown in FIG. Thereby, the distortion added to the silicon substrate 2 can be reduced. By obtaining the attenuation rate of the strain amount when the stress relaxation layer 56 is provided in advance, strain measurement in a range larger than the critical fracture strain amount of the silicon single crystal can be made possible. The resin layer 56 preferably has a Young's modulus smaller than that of a silicon substrate.

  A second embodiment of the present invention will be described with reference to FIGS. In the first embodiment, the case where the antenna 9 is arranged on the chip 101 has been described. However, as described above, the antenna 9 may be provided outside the chip 101. When a frequency band of 10 to several hundred megahertz is used for the radio wave of the reader 201, the radio wave is not easily affected even when moisture exists between the mechanical quantity measuring device 1 and the reader 201. . When the frequency band is used, since the density of the electromagnetic flux is small, a relatively large antenna is required to perform stable communication over a long distance. 7 includes a resin tape 51, a layer of the antenna 9 formed on the resin tape 51, and a silicon substrate chip 101 installed on the resin tape 51. At least a strain is provided on one main surface of the chip 101. A sensor, an amplification conversion circuit that amplifies the signal from the strain sensor and converts it into a digital signal, a transmission circuit that transmits the converted digital signal to the outside of the semiconductor substrate, and a power supply circuit, and The transmission circuit is formed to be in electrical communication with the antenna 9. As shown in the figure, the silicon substrate chip 101 is preferably arranged so as to be surrounded by the antenna 9. The antenna formed on the resin tape is joined with a pad 120 or the like.

  Specifically, as shown in the figure, the chip 101 is disposed on a resin tape 51 such as polyimide, and portions corresponding to the antenna layer and the pad 120 are formed on the resin tape 51. The antenna is arranged so as to surround the periphery of the chip 101. Thereby, since the area occupied by the antenna 9 in the mechanical quantity measuring device 1 can be utilized, a sufficient amount of electric power can be supplied to the chip 101, and high-precision measurement can be performed. Further, in order to perform highly accurate measurement, it is desirable that the chip 101 is directly installed on the object to be measured. Therefore, as shown in FIG. 9, a pad 120 connected to the antenna 9 is provided on the upper surface on which the circuit of the chip 101 is formed, and is directly bonded to the antenna 9. Adhere to things. Since the bonding portion 8 that contacts the back surface of the chip 101 can be directly bonded to the object to be measured, accurate strain measurement can be performed. In addition, when the gigahertz band is used for the radio wave frequency of the reader 201, the radio wave energy is higher than that in the frequency band of 10 to several hundred megahertz, so that long distance measurement is possible even with a small antenna.

  Therefore, as shown in FIG. 8, the chip 101 is arranged on the rod-shaped resin tape 52, and the antenna 9 extending on both sides or one side thereof is arranged. In this case, since the occupation area of the mechanical quantity measuring device 1 can be reduced, measurement is performed using the mechanical quantity measuring device 1 even in a region where stress fluctuation occurs in a narrow range such as a local stress concentration field. Can do. The mechanical quantity measuring device 1 is installed on a measurement object and performs measurement. When the measurement object is a metal, the traveling direction of the electromagnetic wave supplied from the reader 201 to the mechanical quantity measurement device 1 is influenced by the metal. Therefore, it is difficult to pass through the antenna 9 near the metal surface because it is bent in the horizontal direction with respect to the surface, and a sufficient amount of electric power cannot be given to the mechanical quantity measuring device 1.

  Therefore, as shown in FIG. 10, the antenna 9 and the measurement object 11 are installed via a highly permeable sheet 55. The highly permeable sheet 55 is more permeable than the measurement object (metal). Providing the highly permeable sheet 55 on the specific object 11 side of the antenna 9 makes it easier for electromagnetic waves from the reader 201 to pass through the antenna 9, so that even if the measurement object 11 is a metal, the chip 101. A sufficient amount of electric power can be supplied, and stable and highly reliable strain measurement can be performed. Here, since it is desirable that the chip 101 is directly installed on the measurement object 11 in order to perform highly accurate strain measurement, the highly permeable sheet 55 excludes the chip 101 as shown in FIG. It is desirable to be provided in the area. Therefore, it is desirable that the sheet has an opening in a region where the chip 101 is located.

Since there are a large number of metal wirings and antennas in the mechanical quantity measuring device 1, the corrosion becomes a problem in a poor environment such as a hot and humid place. Therefore, when the chip 101 is placed on a resin tape 51 such as polyimide and the antenna 9 is stretched around the periphery, the silicon chip 101 is covered with a resin 58 having rigidity higher than that of the resin tape 51 in FIG. The resin tape 51 is covered. A form in which at least a part of the resin tape 51 is covered may be employed. Specifically, as shown in the figure, the entire mechanical quantity measuring device 1 is covered with a resin 58 such as polyethylene terephthalate to form a card. The resin 58 has higher rigidity than the resin tape 51. Further, it is preferable to place a mark 57 in the strain measurement direction on the card. Corrosion resistance can be improved by carding the entire mechanical quantity measuring device 1 with the resin 58. Further, since the resin 58 does not interfere with the radio wave sent from the reader 201 to the antenna 9 and has better adhesion than the silicon substrate 2, it is difficult to peel off even when it is attached to the object to be measured. Highly accurate strain measurement can be performed. Further, since the side surface of the chip 101 is covered and restrained with the resin 58, highly accurate strain measurement can be performed. Furthermore, by making the resin 58 light-shielding, the influence of light on the strain sensor 8 can be suppressed, and the resin 58 having a low Young's modulus between the chip 101 and the DUT 11 is measured. Since the amount of strain applied to the silicon substrate 2 can be reduced by intervening, the reliability is high and measurement can be performed in a wide range of strain amounts.
A third embodiment of the present invention will be described with reference to FIG. In order to perform more accurate strain measurement, it is desirable to dispose the strain sensor 3 in a location that is more susceptible to strain. Accordingly, in FIG. 12, the main surface on which the strain sensor is formed on the object to be measured has an installation area for the object to be measured. Specifically, as shown in the figure, the chip is turned over so that the thin film group is on the lower side of the chip and attached to the object to be measured 11. Since the mechanical quantity measuring device 1 according to the present invention transmits strain information obtained by the strain sensor 3 to an external reader in a wireless manner, strain measurement can be performed even in a state where it is adhered to the inside. As described above, when the chip 101 is bonded to the measurement object 11, the amount of strain transmitted from the measurement object 11 to the silicon substrate 2 is larger as it is closer to the bonding interface. For this reason, when the chip | tip 101 is attached inside out and the strain sensor 3 is made to adjoin to the measuring object 11, since the strain sensor 3 will be arrange | positioned in the area | region where a strain sensitivity is large, the advantage that a measurement sensitivity rises. There is. Further, only the silicon substrate is exposed to the outside world, and the influence of light on circuits such as the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, and the communication control unit 7 can be suppressed. Further, since the silicon substrate is a single crystal, even when the mechanical quantity measuring device 1 is used in a corrosive environment, it is possible to eliminate various factors that reduce the strength such as intergranular corrosion, and thus high strength. Reliability can be ensured. Further, when the chip 101 is placed upside down, the periphery of the adhesive surface is surrounded by a free surface, so the sensitivity to strain is low at the end of the adhesive surface, and the sensitivity decreases as the center is approached. Therefore, the strain sensor 3 is arranged in a region as close to the center as possible on the bonding surface of the chip 101, and circuits such as the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, the communication control unit 7, the power supply device 10 and the like. Is arranged in a region close to the end. Thereby, a highly sensitive mechanical quantity measuring device having high reliability can be provided.
A fourth embodiment of the present invention will be described with reference to FIGS. The present embodiment basically has the same configuration and characteristics as the first embodiment, but in addition, the Wheatstone bridge circuit 102 composed of the resistance layer of the strain sensor 3 and the resistance layer of the dummy resistor 21 is made of the same single crystal. This is a mechanical quantity measuring device provided in the silicon substrate 2. A circuit diagram of the Wheatstone bridge circuit is shown in FIG. In the present embodiment, the Wheatstone bridge 102 is described as being configured by using two strain sensors 3 and two dummy resistors 21. A one-active gauge type Wheatstone bridge circuit having one strain sensor 3 and three dummy resistors 21 may be used. In FIG. 13, the two strain sensors 3 are referred to as a strain sensor 3a and a strain sensor 3b, and the two dummy resistors 21 are referred to as a dummy resistor 21a and a dummy resistor 21b. It is assumed that a dummy resistor 21a, a strain sensor 3b, and a dummy resistor 21b are connected in this order clockwise from the strain sensor 3a to form a Wheatstone bridge circuit, and between the dummy resistor 21a and the strain sensor 3b and the dummy. An input voltage is applied between the resistor 21b and the strain sensor 3a, and an output voltage is detected between the strain sensor 3a and the dummy resistor 21a and between the strain sensor 3b and the dummy resistor 21b. And

  Since the strain sensor 3 has a very small amount of resistance change due to strain, if it is amplified as it is, signal processing at the subsequent stage becomes complicated. Therefore, normally, as seen in the usage of the strain gauge, by forming the Wheatstone bridge circuit 102, an output voltage proportional to the resistance change of the strain sensor 3 is obtained and then amplified and used as a value proportional to the strain. . Further, by making the temperature state of the resistance value of the dummy resistor 21 the same as the temperature state of the strain sensor 3, there is also an advantage that the Wheatstone bridge circuit 102 becomes a temperature compensation circuit. At this time, it is desirable that the dummy resistor 21 in the Wheatstone bridge circuit 102 is not attached to the object to be measured and is maintained in an unstrained state.

  However, when an attempt is made to form the Wheatstone bridge circuit 102 in the mechanical quantity measuring device, the mechanical quantity measuring device forms a circuit on one single-crystal silicon substrate 2 and uses the back surface of the silicon substrate as the bonding portion 8 to be measured. Since the measurement is performed by being attached to the circuit, there is a possibility that circuit portions other than the strain sensor 3 may be affected by the strain. Therefore, if the Wheatstone bridge circuit 102 is formed in the same silicon surface, the dummy resistor 21 may cause a resistance change similar to that of the strain sensor 3.

  FIG. 14 (1) shows a layout diagram of the Wheatstone bridge circuit 102 in the present embodiment, which has made it possible to avoid this problem. The adjacent resistors in the bridge circuit are formed so that the difference is smaller than the opposing resistors. In the Wheatstone bridge circuit 102, the strain sensors 3a and 3b are formed by locally diffusing a p-type impurity layer in the silicon substrate 2, and the longitudinal direction thereof is the <110> direction. Similarly, the dummy resistor 21 is formed by locally diffusing a p-type impurity layer in the silicon substrate so that the longitudinal direction of the straight line portion is <100>. Further, it is desirable to form the strain sensor 3 and the dummy resistor 21 so that their resistance values are substantially the same. By forming the strain sensor 3 with a p-type impurity diffusion layer and making the <110> direction the longitudinal direction, there is an advantage that the stress sensitivity in the longitudinal direction can be increased. Further, by forming the dummy resistor 21 with a p-type impurity diffusion layer and setting the longitudinal direction to <100>, the sensitivity to normal stress can be minimized. In addition, since the strain sensor and the dummy resistor can be constituted by the same p-type impurity layer, the resistance value can be made substantially the same by forming both at the same time, for example, using the same mask or by the same process. There is. For example, when both impurity layers are formed by performing ion implantation of p-type impurities at the same time, almost the same sheet resistance value can be obtained by the strain sensor 3 and the dummy resistor 21, so that the output offset amount of the Wheatstone bridge circuit is minimized. Can be. In this case, the impurity diffusion treatment is preferably performed by ion implantation and subsequent activation treatment because the impurity dose amount accuracy is high and the diffusion profile can be formed with good reproducibility. In addition, since the strain sensor and the dummy resistor are collectively formed on the same chip with the same p-type impurity layer, variation in the concentration distribution of the diffusion layer can be suppressed, so that the sheet resistance value can be made the same, and the resistance value There is also an advantage that the temperature dependence can be made the same. In the above description, the strain sensor is described as being formed in the <110> direction and the dummy resistor is defined as being in the <100> direction. However, this is an ideal state, and even when an angle shift occurs in manufacturing, the effect is sufficiently obtained. . That is, it is effective if the strain sensor is arranged closer to the <110> direction than the <100> direction, and the dummy resistor is arranged closer to the <100> direction than the <110> direction.

  Even when the diffusion resistance layer is n-type, the strain sensor 3 and the dummy resistor 21 can be formed on the same substrate as shown in FIG. The strain sensor 3 is formed by locally diffusing an n-type impurity layer in the silicon substrate 2, and its longitudinal direction is the <100> direction. Similarly, the dummy resistor 21 is formed by locally diffusing an n-type impurity layer in the silicon substrate so that the longitudinal direction of the straight line portion is <110>. Further, the strain sensor 3 and the dummy resistor 21 are formed to have substantially the same resistance value. By forming the strain sensor 3 with an n-type impurity diffusion layer and making the <100> direction the longitudinal direction, there is an advantage that the stress sensitivity in the longitudinal direction can be increased. Further, by forming the dummy resistor 21 with an n-type impurity diffusion layer and setting the longitudinal direction to <110>, sensitivity to vertical stress can be minimized. The Wheatstone bridge circuit using the n-type impurity diffusion layer thus fabricated can have substantially the same resistance value as in the p-type diffusion layer, and the output offset amount can be minimized and the temperature dependence of the offset amount can be substantially the same. It has the advantage that it can be done. When a Wheatstone bridge is fabricated with an n-type impurity diffusion layer, the stress sensitivity in the normal direction of the chip top surface of the dummy resistor is greater than that with a p-type impurity diffusion layer, but the sensitivity of the strain sensor 3 is increased. With advantages. In the above description, the strain sensor is described as being formed in the <100> direction and the dummy resistor is defined as being in the <110> direction. However, this is an ideal state, and there is a sufficient effect even when an angle shift occurs in manufacturing. . That is, it is effective if the strain sensor is arranged closer to the <100> direction than the <110> direction, and the dummy resistor is arranged closer to the <110> direction than the <100> direction.

  Even when a design is performed in which the impurity concentrations of the strain sensor and the dummy resistor are not matched, a slight error may occur in the temperature compensation of the offset amount, and the deviation of the resistance values of the strain sensor 3 and the dummy resistor 21 may occur. However, other effective effects can be obtained as well.

Furthermore, when the strain generation direction is determined as a specific direction of one axis, and the strain amount in that direction is measured, the strain sensor 3 is set in the strain measurement direction as shown in FIGS. 14 (3) and 14 (4). The dummy resistor 21 is arranged so as to have a longitudinal direction in which current flows in a direction perpendicular to the strain measuring direction. In the case of the p-type diffusion layer, the strain sensor 3 and the dummy resistor are arranged so as to be orthogonal to the <110> direction, and in the case of the n-type diffusion layer, the strain sensor 3 and the dummy resistance are arranged to be orthogonal to the <100> direction. To do. In the silicon single crystal, when the diffusion layer is disposed as described above, the dummy resistor 21 disposed perpendicularly to the strain sensor 3 disposed in parallel to the strain measurement direction is opposite to the strain sensor 3. Since the resistance value changes, the amount of output from the bridge circuit increases, and a large output can be obtained even with a small amount of strain, enabling highly accurate strain measurement.
The order of the diffusion layers of the bridge will be described below.

When a Wheatstone bridge is formed on the silicon substrate 2 using a p-type diffusion resistor, two strain sensors 3a and 3b whose longitudinal direction is parallel to the <110> direction of the silicon crystal as shown in FIG. The Wheatstone bridge is composed of two dummy resistors 21a and 21b whose longitudinal direction is formed in a direction parallel to the <100> direction of the silicon crystal. In a Wheatstone bridge circuit, ideally, the resistance values of the four resistors should be exactly the same in an unstrained state. When the resistance value of the four resistor are equal, when loaded with voltage V _in in FIG. 13, the resistance 3a and the resistor 21b, since the voltage drop amount is equal in resistance 3b and the resistor 21a, V _out the voltage There is no difference and the output is 0, facilitating amplification processing in the subsequent stage. However, even if the design is such that the resistance value is completely the same, when the diffusion layer is actually fabricated on the silicon substrate, the variation in the gas concentration of the impurity atoms has an effect, and the resistance of the formed resistance The resistance value may be different.

In order to eliminate the change of the resistance value due to the variation in gas concentration as much as possible, it is desirable to form the four resistors in regions as close as possible as shown in FIG. Furthermore, even if the resistance values of all four resistors do not match, in order to make the offset of the output voltage _Vout zero when there is no distortion, at least four resistance values R The ratio may be R _21a : R _3b = R _3b : R _21b . In general, the variation in gas concentration is considered to have a certain inclination in the silicon substrate surface. For example, as shown in FIG. 14 (1), resistors 3a and 21a, resistors 21b and 3b are provided. By arranging the resistors 3a → resistors 21a → resistors 21b → resistors 3b in this order from one side to the other, the ratio of the four resistance values should be close to the relationship of R _21a : R _3b = R _3b : R _21b Can do. Adjacent resistances are made smaller than the ratio of opposing resistances. It is possible to realize a Wheatstone bridge circuit that can substantially reduce the output in the undistorted state. This arrangement is not limited to the p-type diffused resistor shown in FIG. 14A, and the same effect can be obtained even in the case of a diffused resistor having a different shape or arrangement direction or an n-type diffused resistor. This arrangement is not limited to a Wheatstone bridge formed by a silicon single crystal diffusion layer, and may be a Wheatstone bridge formed of, for example, a polycrystalline silicon thin film or a metal thin film. Obtainable.

  When manufacturing the four diffusion resistors constituting the Wheatstone bridge circuit 102, it is desirable to make the environment of each diffusion resistor peripheral region the same in order to equalize the resistance values of all the diffusion resistors. . As shown in FIGS. 14 (1) to 14 (4), the Wheatstone bridge circuit according to the present invention is characterized in that resistors having different directions are made as close as possible in order to reduce variation in diffusion amount. Therefore, the situation around the four diffused resistors is different. In this case, when the resistance shape is formed by etching the mask for forming the diffusion layer, the gas concentration distribution above each diffusion resistance becomes non-uniform in the etching, and the resistance diffusion amount may vary. There is sex.

  Accordingly, the form disclosed in FIG. 15 includes a Wheatstone bridge circuit having a plurality of resistance layers including strain sensor resistors 3a and 3b and dummy resistors 21a and 21b on the circuit forming surface of the silicon chip 101, and a Wheatstone bridge circuit. A conversion circuit for converting the digital signal into a digital signal, a transmission circuit for transmitting the digital signal to the outside of the semiconductor substrate, and a power supply circuit, and formed along the longitudinal direction of the strain sensor resistor, A dummy diffusion layer 15 which is a resistance layer that does not constitute a Wheatstone bridge circuit is provided. Further, the diffusion layer 15 which is a resistance layer that does not constitute the Wheatstone bridge circuit is formed on both sides in the longitudinal direction of the resistance layer of the Wheatstone bridge. Alternatively, a dummy diffusion layer having substantially the same shape and parallel to the diffusion resistance is disposed around the impurity diffusion resistance constituting the bridge circuit.

Further, the resistance layer constituting the Wheatstone bridge circuit includes an impurity diffusion layer, and a diffusion layer (dummy diffusion layer) that is not electrically connected to the circuit is provided in a region closer to the other resistance layer from one resistance layer. Provided. Therefore, the resistance layer constituting the circuit is arranged via the diffusion layer not connected to the circuit.
As shown in FIG. 15, by disposing the resistors 15 serving as dummy diffusion layers around each of the four diffused resistors forming the bridge circuit, the difference in the surrounding environment of each resistor can be reduced. . The resistor 15 does not constitute a Wheatstone bridge circuit. The dummy diffusion layer preferably has substantially the same shape as each of the four diffusion resistors forming the bridge circuit. Further, in order to make the surrounding environment of the four diffusion resistors forming the bridge circuit the same as much as possible, dummy resistors are arranged on both sides in the longitudinal direction of one diffusion resistor so as to be substantially parallel to the diffusion resistors. It is desirable. Further, by forming the dummy diffusion layer 16 surrounding the entire four resistors forming the bridge circuit, the gas concentration above the diffusion resistance shape when the mask is formed with the shape of another circuit arranged around the strain sensor. Nonuniformity can be reduced. As a result, uniform diffusion layer formation can be realized, and a Wheatstone bridge circuit in which the difference in resistance values of all resistors can be made as small as possible can be manufactured, and the strain measurement accuracy is improved. The dummy diffusion layer may be disposed only around the four diffusion resistors, or may be disposed only around the bridge circuit. In these cases, the effect of reducing the non-uniformity of the gas concentration during mask etching is slightly reduced, but the area occupied by the strain sensor can be reduced, and the positions of the four resistors forming the bridge circuit are close to each other. There is an advantage that variation in resistance value when forming the impurity diffusion layer can be reduced.

  As the resistance value of the diffusion layer increases, the amount of change in resistance when strain is applied increases, so the measurement accuracy improves. In addition, the amount of current flowing through the resistor is reduced, leading to lower power consumption. When the width of the resistor is w and the length is l, the resistance value is proportional to l / w. Therefore, the resistance value can be increased by increasing l / w. However, when l / w is increased, the diffusion resistance becomes elongated. In the Wheatstone bridge circuit according to the present invention, it is desired that the diffusion layer be contained in a narrow region as much as possible in order to prevent the dispersion of the diffusion concentration in each diffusion resistor from becoming large.

  Therefore, as shown in FIG. 16, the diffusion of the diffusion concentration can be suppressed as much as possible by folding back the impurity diffusion resistor 17 and keeping the area occupied by the diffusion resistor within a small range. In addition, when a folded portion exists in one diffusion resistor, a difference in electron velocity occurs between the outer peripheral region and the inner peripheral region at the folded corner portion, and it is difficult to adjust the resistance value during resistance fabrication.

  Therefore, as shown in FIG. 16 (2), the resistance layer includes a linear portion made up of an odd number of linear resistors 17 whose longitudinal directions are in the same direction, and an even number of connecting portions connecting the linear portions. . Here, the via 18 is used. Here, one more linear resistor 17 than the number of times of folding is arranged, and each diffusion resistor is connected using a via 18 made of metal foil to produce a folding resistor. By joining the ends of the linear resistance using vias made of a metal thin film, it is possible to eliminate the delay of the electron moving speed at the turn-back corner, and to obtain the target resistance value with higher accuracy. The via may be pulled upward from the diffusion resistance forming surface using a contact, or may be metallized using a silicide reaction. As a result, variations in resistance values among the four diffusion resistors can be suppressed, so that the offset amount when no strain is applied can be reduced to zero, and a highly reliable strain amount measurement can be performed. Here, it is important to use the via 18 having a smaller impedance than the diffused resistor 17, and the via 18 is not limited to a metal foil. Furthermore, since a diffusion layer having a length direction in a direction different from the longitudinal direction of the diffusion resistance for measuring strain can be excluded, precise measurement can be performed. In FIG. 16 (2), the folding resistance is formed by connecting two linear resistors at one place, but the number of folding may be two or more. When a plurality of turns are performed, since the area occupied by the entire length of the resistor can be reduced, variations in the diffusion layer concentration can be suppressed.

  Furthermore, the number of turns is desirably an even number of turns using an odd number of linear resistors as shown in FIG. This mechanical quantity measuring device obtains a driving electromotive force by electromagnetic induction from an external electromagnetic wave. However, since the antenna 8 and the Wheatstone bridge 102 are arranged in a minute region on the same substrate, the electromagnetic wave is also generated in the Wheatstone bridge. May cause an induced electromotive force. Electromagnetic induction is a phenomenon in which current is generated in a specific direction of a wiring due to the influence of the magnetic force change component when a magnetic field line passing through the inside of a region surrounded by the wiring changes according to Faraday's law. When a magnetic force change occurs in the direction perpendicular to the paper with respect to the bending resistance shown in FIG. 16 (3), the current generated in 18a-18b-18c and the current flowing in 18b-18c-18d are opposite. These currents cancel each other, and the generation of an electromotive force that becomes noise when measuring the amount of strain can be suppressed, so that more accurate measurement can be performed.

In addition, in the four impurity diffusion resistors forming the bridge circuit, even when the diffusion resistors constituting the bridge are folded back an odd number using an even number of resistors, as shown in FIG. By placing the remaining two diffused resistors so that the electromotive force flows in the opposite direction to the direction of the induced electromotive force generated in the two resistors, the induced electromotive force generated in the bridge is canceled out and the noise is low Highly accurate strain measurement is possible. In FIG. 17, an arrow indicates the direction of current flow when a magnetic field change occurs from the front to the back in the direction perpendicular to the paper surface. FIGS. 18 (3) and 18 (4) show an arrangement example of p-type diffused resistors and n-type diffused resistors when the strain sensor 3 and the dummy resistor 21 have an angle of approximately 45 °, FIGS. 18 (1) and 18 (2) shows an arrangement example of p-type diffusion resistors and n-type diffusion resistors when the strain sensor 3 and the dummy resistor 21 have an angle of approximately 90 °.

  Strain information detected by the strain sensor 3 is transmitted to the outside using circuits such as the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, the communication control unit 7, and the power supply device 10. Circuits such as the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, the communication control unit 7 and the like are formed on the same silicon substrate as the strain sensor 3 and include a large number of diffusion resistors. When the silicon substrate 2 is strained, these diffused resistors also change in specific resistance, so that the circuit may not operate normally. Therefore, in the case of the p-type diffusion layer, the longitudinal direction of the diffusion resistors constituting the analog / digital converter 5, the rectification / detection / modulation / demodulation circuit unit 6, the communication control unit 7 and the like is the <100> direction of the silicon crystal and the n-type. In the case of the diffusion layer, the strain sensitivity of the diffusion layer can be reduced by matching with the <110> direction of the silicon crystal, so that the normal operation of the mechanical quantity measuring device can be compensated.

  When the strain sensor 3 is formed of a p-type diffusion layer, when the strain applied in the measurement direction of the strain sensor 3 is tensile, the amount of change in specific resistance shows a positive value, whereas when it is compressed, the amount of change is negative. Indicates. When the strain sensor 3 is formed with an n-type resistance, the positive and negative directions are reversed from those of the p-type diffusion layer, the positive specific resistance change is shown in the tension, and the negative specific resistance change is shown in the compression. Show. That is, an operational amplifier that amplifies the output voltage of the strain sensor needs to have an amplification function corresponding to both positive and negative outputs. However, in general, an operational amplifier circuit corresponding to both positive and negative outputs becomes nonlinear amplification in the vicinity of 0 where the sign is reversed, and cannot perform accurate amplification. Therefore, as shown as an example in FIG. 19, an offset is provided in the input voltage of the operational amplifier circuit. For example, an operational amplifier that has an amplified value that varies according to the output value from the Wheatstone bridge circuit and an amplified value that is a predetermined value (or a predetermined value when no signal is input before the operational amplifier circuit (after the circuit, etc.)) Output at the output of the circuit. That is, for example, the output of the operational amplifier circuit is configured to be a value obtained by adding a preset value to a value based on the output from the Wheatstone bridge circuit. As a result, a stable linear output can be obtained even in the amplification in the vicinity of the region where the strain amount in which the strain amount shifts from compression to tension is zero. FIG. 19 shows a general operational amplifier circuit. For example, the offset amount is desirably ½ of the voltage input to the strain sensor 3. As a result, amplification in the same range can be performed for tensile and compressive strains. Here, the offset amount does not need to be exactly ½ with respect to the input voltage of the strain sensor 3, and a similar effect can be obtained by making the offset amount almost ½. In addition, operational amplifiers that support positive and negative outputs generally have a more complicated structure than those that do not generally support power consumption, resulting in an enormous amount of power consumption. Since it is essential that the mechanical quantity measuring device in the present invention has low power consumption, adding an offset to the operational amplifier circuit leads to low power consumption of the entire circuit.

It is a schematic diagram of the mechanical quantity measuring device in the present invention. It is a schematic diagram which shows the communication and power supply method of the mechanical quantity measuring device in this invention. It is a figure which shows the mechanical quantity measuring device shape which is 1st embodiment in this invention. It is a figure which shows the mechanical quantity measuring device structure which is 1st embodiment in this invention. It is a figure which shows the mechanical quantity measuring device structure which is 1st embodiment in this invention. It is a figure which shows the installation method of the mechanical quantity measuring device which is 1st embodiment in this invention. It is a figure which shows the structure of the mechanical quantity measuring device which is 2nd embodiment in this invention. It is a figure which shows the structure of the mechanical quantity measuring device which is 2nd embodiment in this invention. It is a figure which shows the structure of the mechanical quantity measuring device which is 2nd embodiment in this invention. It is a figure which shows the structure of the mechanical quantity measuring device which is 2nd embodiment in this invention. It is a figure which shows the structure of the mechanical quantity measuring device which is 2nd embodiment in this invention. It is a figure which shows the installation method of the mechanical quantity measuring device which is 3rd embodiment in this invention. It is a figure which shows the outline | summary of the Wheatstone bridge circuit regarding 4th embodiment in this invention. It is a figure which shows the diffused layer arrangement | positioning direction which is 4th embodiment in this invention. It is a figure which shows the diffused layer arrangement | positioning which is 4th embodiment in this invention. It is a figure which shows the diffused layer structure which is 4th embodiment in this invention. It is a figure which shows the diffused layer arrangement | positioning direction which is 4th embodiment in this invention. It is a figure which shows the diffused layer arrangement | positioning direction which is 4th embodiment in this invention. It is a figure which shows the structure of the circuit which is 4th embodiment in this invention.

Explanation of symbols

1 .... Mechanical quantity measuring device 2 .... Si substrate 3, 3a-3b ... ... Strain sensor 4 ... Amplifier group 5 ... Analog / Digital converter 6 ... Rectification / detection / modulation / demodulation circuit 7 ... Communication control unit 8・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Adhesion 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Antenna 10・ ・ ・ ・ Power supply device 11 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ DUT 12 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Protective material 13・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inclusion 14 for adhesion / fixation ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・-Wiring 15 ... Dummy diffusion layer 16 ... Dummy diffusion layer 17 ... ········ Impurity diffusion resistors 18, 18a to 18d ··· Vias 21, 21a to 21b ······ Dummy resistors 51 ··· ········· Resin tape 55 ······························································ Resin Stress-reducing layer 57 ..... Strain measuring direction mark 58 ..... Resin 101 ... ... chip 102 ... Wheatstone bridge circuit 120 ... pad 201 ... ... reader 202 · · · · · · reader antenna

Claims (1)

In a mechanical quantity measuring device that has a strain detector formed on a single crystal semiconductor substrate and is pasted or embedded in the measurement object in order to measure the strain of the measurement object,
The strain detector
Each sensor resistance layer and dummy resistance layer includes a pair of sensor resistance layers made of impurity diffusion resistance and a pair of dummy resistance layers made of impurity diffusion resistance formed on one main surface of the single crystal semiconductor substrate. A Wheatstone bridge circuit having approximately the same resistance value;
A plurality of second resistance layers formed along the longitudinal direction of each of the sensor resistance layers and the dummy resistance layers and made of impurity diffusion resistors that do not constitute the Wheatstone bridge circuit;
The second resistive layers are electrically disconnected from each other ;
Each of the sensor resistance layer and the dummy resistance layer includes an odd number of the impurity diffusion resistors having a longitudinal direction oriented in the same direction and a via made of an even number of metal thin films connecting the linear portions. A mechanical quantity measuring device characterized by that.

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