JP2013195151A - Thermal type element and method for determining resistance value temperature coefficient of temperature measuring resistor in thermal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal type element capable of determining a resistance value temperature coefficient of a temperature measuring resistor with a simple measurement.SOLUTION: A thermal element 10 comprises: a first temperature measuring resistor 3 for detection; a second temperature measuring resistor 5 for temperature coefficient measurement; and a diode 7. The first temperature measuring resistor 3 is arranged so as to be bridged over a cavity 1a formed on a semiconductor substrate 1. The second temperature measuring resistor 5 is arranged at a position different from the cavity 1a on the semiconductor substrate 1. The second temperature measuring resistor 5 has the same resistance value temperature coefficient as the resistance value temperature coefficient of the first temperature measuring resistor 3. The diode 7 is formed by a P-type region 7p+ and an N-type region 7n which are formed on the semiconductor substrate 1. The diode 7 is arranged at a lower part of the second temperature measuring resistor 5.

Description

  The present invention relates to a thermal element and a method for determining a temperature coefficient of a resistance temperature detector in the thermal element.

  Today, the manufacture of semiconductor integrated circuit elements such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) is becoming a barrier to entry by introducing production equipment sold by semiconductor device manufacturers. As a result, production bases are globalized. Moreover, the price of the element is very low.

  In addition, a large number of sensors incorporated in CMOS (Complementary Metal Oxide Semiconductor) with uniform characteristics are produced by MEMS (Micro Electro Mechanical System) technology using a semiconductor integrated circuit manufacturing process.

  The mainstream of present MEMS sensor production facilities is diverted to IC and LSI production facilities. However, the MEMS sensor manufacturing process is not compatible with the conventional semiconductor integrated circuit manufacturing process, and is designed to correspond to a measurement standard that is a reference for the sensor reaction amount in order to convert the reaction amount obtained by the sensor into a physical quantity. An arrangement calibration process is required.

  Typically, semiconductor device manufacturers do not have an automated system for calibrating large numbers of MEMS sensors. Therefore, the development of unique production technology is required, and a large amount of new investment is required. Thus, MEMS sensors cannot be easily produced anytime and anywhere. Since the entry conditions of manufacturers are limited in the manufacture of the MEMS sensor, the price of the MEMS sensor is expensive, and the spread of the MEMS sensor is restrained.

  As a MEMS sensor, there is a thermal element including a temperature measuring resistor that handles heat, such as a temperature sensor and a humidity sensor (see, for example, Patent Documents 1, 2, and 3). There is a hygrometer as an atmosphere meter using such a thermal element. The principle of the hygrometer will be briefly described.

  In general, it is known that a hygrometer using the thermal conductivity of gas has excellent responsiveness and high reliability. The amount of heat that flows through the upper and lower surfaces of a predetermined cross section in an isotropic object in the normal direction in a unit time is proportional to the temperature gradient in the normal direction and the cross sectional area, and this proportionality constant is the thermal conductivity. The thermal conductivity of gas is a function of constant pressure specific heat, and constant pressure specific heat is a function of gas molecular weight. Therefore, the thermal conductivity is different between the case of only air and the case where gas components and moisture having different molecular weights are contained in the air. A hygrometer using the difference in thermal conductivity of gas obtains the humidity from the resistance value change amount of the resistor caused by the difference in the amount of heat released from the heated resistor into the atmosphere.

FIG. 5 is a schematic plan view and cross-sectional view for explaining a conventional thermal element. In FIG. 5, the cross-sectional view shows a cross section at the XX position in the plan view.
The semiconductor substrate 101 is formed with a hollow portion 101a formed of a concave portion. A resistance temperature detector 103 is provided on the hollow portion 101a so as to be bridged. At both ends of the resistance temperature detector 103, electrodes 103Ia and 103Ib for supplying current are provided. The resistance temperature detector 103 includes voltage measurement wiring and electrodes 103Va and 103Vb branched between the electrodes 103Ia and 103Ib.

  The resistance temperature detector 103 is overheated by supplying a current of a predetermined magnitude. When the humidity of the ambient temperature of the resistance temperature detector 103 is different, the amount of heat radiated from the heated resistance temperature detector 103 to the ambient atmosphere is different, so the resistance value of the resistance temperature detector 103 is the humidity in the ambient atmosphere. It changes according to. Therefore, the humidity of the surrounding atmosphere can be determined by measuring the resistance value of the resistance temperature detector 103.

The atmosphere meter disclosed in Patent Document 1 detects a predetermined gas in the atmosphere based on a change in the resistance value of the resistance temperature detector 103 heated in the atmosphere.
FIG. 6 is a diagram for explaining an example of a waveform diagram of the current supplied to the resistance temperature detector 103 in the hygrometer.

  The resistance temperature detector 103 has low temperature driving (time t1 to time t2) in which the resistance change of the resistance temperature detector 103 is heated at a low temperature that is influenced only by the ambient temperature, and resistance change of the resistance temperature detector 103. Electric power is supplied by high temperature driving (from time t2 to time t3) during low temperature driving that is heated at a high temperature that is sensitive to the temperature of the atmosphere and a predetermined gas.

  For example, from time t 1 to time t 2, a small pulse current having a peak value of 2 mA (milliamperes) and a pulse width of 50 ms (milliseconds) is applied to the resistance temperature detector 103. Further, a large pulse current having a peak value of 8 mA and a pulse width of 50 ms is applied to the resistance temperature detector 103 from time t2 to time t3. The pause time from time t3 to time t4 is 100 ms. The application of the small pulse current and the large pulse current to the temperature measuring resistor 103 is repeated with the time t1 to the time t4 as one set.

  FIG. 7 is a diagram illustrating an example of the relationship between absolute humidity and output voltage in a hygrometer. The horizontal axis represents humidity, and the vertical axis represents the output voltage of the resistance temperature detector 103.

  From FIG. 7, it can be seen that the output voltage of the resistance temperature detector 103 with respect to absolute humidity is temperature dependent. Therefore, the hygrometer stores the measurement values shown in FIG. 7 as a table in a storage medium, outputs the detected value as humidity after performing a calculation corresponding to the temperature.

  In the prior art hygrometer, in order to eliminate the influence of manufacturing variations of the thermal element including the resistance temperature detector 103 and improve the humidity accuracy as much as possible, each thermal element is stored in a storage medium. The work to get the table for, that is, calibration is required.

  In general, the thermal element is calibrated by measuring the resistance value of the resistance temperature detector 103 and removing the initial defect, and then inserting the thermal resistance element into the thermostat and measuring the temperature characteristic of the resistance temperature detector 103. Next, a table is created in which the output of the resistance temperature detector 103 with respect to temperature and humidity is obtained while changing the temperature and humidity conditions. In this way, necessary information about each thermal element may be acquired. However, as an effective method for shortening the time required for calibration, a reference table is prepared in advance, and the resistance temperature detector 103 is prepared. There is a method of correcting the temperature in accordance with the temperature characteristic of the.

  FIG. 8 is a diagram for explaining a temperature characteristic (TCR, Temperature Coefficient of Resistance) of platinum used as a resistance temperature detector. The horizontal axis indicates the temperature, and the vertical axis indicates the resistance value.

  In general, metals have a so-called positive temperature coefficient in which electric resistance increases almost in proportion to temperature. Among them, platinum has a characteristic that the temperature coefficient of resistance is large compared to other metals, the linearity of the temperature coefficient is good, and the linearity of the temperature coefficient is good in a wider temperature range. In Japan, only platinum is standardized as a resistance temperature detector (Japanese Industrial Standards JIS C1604-1997).

  When a resistance temperature detector is formed by etching technology after a platinum thin film is formed on a semiconductor wafer by sputtering, the resistance value at a certain temperature varies depending on the thickness variation during platinum film formation and the size variation during etching. There is. In addition, the temperature coefficient of the resistance temperature detector made of platinum may vary depending on the base of the platinum film to be formed, the heat treatment temperature during the platinum film formation, the heat treatment temperature after the film formation, migration due to continuous energization, and the like.

  In a thermal element provided with a resistance temperature detector, an accurate temperature coefficient is required for the resistance of the resistance temperature detector in order to correct the output voltage of the resistance temperature detector. In order to measure the resistance value temperature coefficient of the resistance temperature detector with higher accuracy, a constant temperature bath capable of controlling the ambient environment of the thermal element at a constant temperature is required. For example, measurement of a resistance value temperature coefficient of a resistance temperature detector requires a large-scale facility having a temperature standard composed of a constant temperature environment such as an oil bath.

  Moreover, it takes a long time to bring the thermostat to a predetermined constant temperature. For example, when the operation of the thermostatic chamber is started, if the temperature of the thermostatic chamber has a temperature difference of 10 ° C. or more with respect to the set temperature, a stable time of 2 hours or more is secured. Further, even when the difference between the temperature of the thermostatic chamber and the set temperature is less than 1 ° C., a stable time of 30 minutes is ensured. Then, if the temperature of the thermostatic chamber does not fall within the set temperature range, for example, ± 0.1 ° C. of the set temperature even after 12 hours have elapsed from the start of operation of the thermostatic bath, the measurement is stopped.

  In order to obtain the temperature coefficient of the resistance temperature detector of the thermal element, for example, the resistance value of the resistance temperature detector is measured in increments of 15 ° C. in a temperature range of 5 to 80 ° C. This measurement requires more than 12 hours. In order to shorten the measurement time, two measurement temperatures may be used. However, in this case, there is a problem that the measurement temperature is easily affected by variations during measurement.

  With respect to the relationship between the temperature and the resistance value obtained in this way, a temperature coefficient is obtained by linear approximation. This temperature coefficient is used when setting the resistance value of the resistance temperature detector in order to raise the temperature of the resistance temperature detector as a heater and raise the temperature to a set temperature during operation of the atmosphere meter.

  As described above, the operation of obtaining calibration information of the thermal element having a resistance temperature detector is expensive because it takes a long time to create a stable temperature environment where the temperature standard is constant. Compared to the quick setting of elements other than the thermal element in the atmosphere meter using simple electric transmission equipment and optical devices, thermal elements are a bottleneck to handle in large quantities in the mass production process. Yes. Therefore, it is difficult to reduce the cost of the atmosphere meter.

  For example, the price of a calibrated atmosphere meter is several to several tens of times the price of an uncalibrated atmosphere meter. In particular, the higher the accuracy, the higher the accuracy of calibration at the time of production, which requires cost and time.

  In addition, in order to perform high-precision calibration, a temperature standard is set in a wide range, and when a high-temperature bath with a high temperature of about several hundred degrees is used, not only the thermal element but also the connector and wiring connected to the thermal element. Heat resistance is required. Since connectors and wiring have low heat resistance for a long time, there is a problem that calibration requiring high temperature is difficult.

  An object of the present invention is to provide a thermal element that can determine a resistance value temperature coefficient of a resistance temperature detector by simple measurement and a method for determining a temperature coefficient of the resistance temperature detector in the thermal element.

  The thermal element according to the present invention is disposed on the semiconductor substrate at a position different from the first temperature measuring resistor for detection disposed by bridging on the cavity formed on the semiconductor substrate, A second temperature measuring resistor for temperature coefficient measurement having the same structure and resistance value temperature coefficient as the first temperature measuring resistor, and a P-type formed on the semiconductor substrate below the second temperature measuring resistor A diode composed of a region and an N-type region.

  The method of determining the temperature coefficient of the resistance temperature detector in the thermal element according to the present invention uses the thermal element of the present invention, and the resistance value of the first resistance temperature detector for a plurality of the thermal elements having the same structure. The following steps are included to determine the temperature coefficient. A diode temperature coefficient measuring step for measuring a forward resistance value temperature coefficient of the diode of any one of the thermal type elements, and changing a current within a predetermined range to the second temperature measuring resistor of the other thermal type element. A resistance value measuring step for measuring a forward resistance value change of the diode and a resistance value change of the second temperature measuring resistor when the second temperature measuring resistor is heated to supply the second temperature measuring resistor; A resistance value of the second resistance temperature detector based on a change in resistance value of the resistance temperature element, a change in forward resistance value of the diode and a temperature change of the second resistance temperature detector that can be calculated by a temperature coefficient of the diode. A temperature measuring resistor temperature coefficient determining step of calculating a temperature coefficient and using the temperature coefficient as a resistance value temperature coefficient of the first temperature measuring resistor.

The method of determining the temperature coefficient of the resistance temperature detector in the thermal element of the present invention is the second resistance temperature detector having the same structure and resistance value temperature coefficient as the first resistance temperature detector using the thermal element of the present invention. The body is heated while measuring its resistance value and the forward resistance value of the diode under the second resistance temperature detector (resistance value measuring step). Since the diode forward resistance temperature coefficient is known in advance (diode temperature coefficient measurement step), it can be calculated from the resistance value change of the second resistance temperature detector, the diode forward resistance value change, and the diode temperature coefficient. Based on the temperature change of the second resistance temperature detector, the resistance value temperature coefficient of the second resistance temperature detector can be calculated. Since the second resistance temperature detector has the same resistance value temperature coefficient as the first resistance temperature detector for detection, the calculated resistance value temperature coefficient of the second resistance temperature detector is used as the resistance of the first resistance temperature detector. The value temperature coefficient can be set (temperature measuring resistor temperature coefficient determination step).
As described above, the thermal element of the present invention and the method for determining the temperature coefficient of the resistance thermometer in the thermal element can determine the resistance temperature coefficient of the resistance thermometer by simple measurement.

It is the schematic top view and sectional drawing for demonstrating one Example of the thermal type | mold element of this invention. It is a figure for demonstrating the temperature characteristic of the forward direction resistance value of a PN junction diode. It is a flowchart for demonstrating one Example of the determination method of the resistance value temperature coefficient of the resistance temperature detector in the thermal type element of this invention. It is the schematic top view and sectional drawing for demonstrating the other Example of the thermal type | mold element of this invention. It is the schematic top view and sectional drawing for demonstrating the conventional thermal type | mold element. It is a figure for demonstrating the example of the waveform figure of the electric current supplied to a resistance temperature detector in a hygrometer. It is a figure which shows the example of the relationship between the absolute humidity and output voltage in a hygrometer. It is a figure for demonstrating the temperature characteristic of the resistance value of platinum used as a resistance temperature detector.

  FIG. 1 is a schematic plan view and cross-sectional view for explaining an embodiment of the thermal element of the present invention. In FIG. 1, the cross-sectional view shows a cross section at the position AA in the plan view.

  The thermal element 10 includes a semiconductor substrate 1. The semiconductor substrate 1 is formed with a hollow portion 1a formed of a concave portion. A first resistance temperature detector 3 is provided on the hollow portion 1a so as to be bridged. At both ends of the first resistance temperature detector 3, electrodes 3Ia and 3Ib for supplying current are provided. The first resistance temperature detector 3 includes voltage measurement wiring and electrodes 3Va and 3Vb branched between the electrodes 3Ia and 3Ib.

  A second resistance temperature detector 5 is provided on the semiconductor substrate 1 at a position different from the cavity 1a. The second resistance temperature detector 5 is formed of the same shape, size and material as the first resistance temperature detector 3. Thereby, the 1st resistance temperature detector 3 and the 2nd resistance temperature detector 5 have the same structure and resistance value temperature coefficient. Similar to the electrodes 3Ia, 3Ib, 3Va, 3Vb of the first resistance temperature detector 3, the second resistance temperature detector 5 includes electrodes 5Ia, 5Ib, 5Va, 5Vb.

  The first resistance temperature detector 3 and the second resistance temperature detector 5 are formed at the same time in the same process, and are arranged at such a distance that the structure and the resistance temperature coefficient are the same. For example, if the first resistance temperature detector 3 and the second resistance temperature detector 5 are arranged at positions far apart from each other, the first temperature measurement resistor 3 and the second resistance temperature detector 5 may be used in the film formation process, photoengraving process, etching process, etc. in the semiconductor device manufacturing process. There may be a slight difference in film quality or dimensions of the constituent material between the resistance temperature detector 3 and the second resistance temperature detector 5. This difference affects the resistance value temperature coefficient of the resistance temperature detectors 3 and 5. Therefore, in this embodiment, the resistance temperature detectors 3 and 5 are arranged at a distance such that the structure and the resistance value temperature coefficient are the same.

  A diode 7 including a P-type region 7p + and an N-type region 7n is formed on the semiconductor substrate 1 below the second resistance temperature detector 5. The diode 7 also includes an N-type region 7n + for taking the potential of the N-type region 7n. N-type region 7n + is formed of an N-type impurity that is deeper than N-type region 7n.

  On the semiconductor substrate 1, wiring and an electrode 7Va for taking the potential of the P-type region 7p + and wiring and an electrode 5Vb for taking the potential of the N-type region 7n + are also provided. The wiring and electrodes 7Va and 7Vb are formed of the same material at the same time as the resistance temperature detectors 3 and 5 in the same process. This eliminates the need for a separate process for forming wiring and electrodes in order to take the potential of the diode 7.

An example of materials and structures of the first resistance temperature detector 3 and the second resistance temperature detector 5 will be described.
The resistance temperature detectors 3 and 5 are made of platinum, for example. The platinum is formed by a high frequency sputtering method. The thickness of the platinum is, for example, 0.3 to 1.0 μm (micrometer). The platinum is patterned into a wiring shape by a dry etching method.

Further, platinum (Pt) constituting the resistance temperature detectors 3 and 5 is protected by an insulating film. The protective insulating film is formed of, for example, a film in which a tantalum pentoxide film (Ta ₂ O ₅ ), a silicon oxide film (SiO ₂ ), and a silicon nitride film (SiN) are stacked. The protective insulating film is formed by CVD (Chemical Vapor Deposition) or sputtering so that the structure and film thickness of the protective insulating film are symmetrical between the upper layer and the lower layer of platinum constituting the resistance temperature detectors 3 and 5. Formed by law. For example, an insulating film and platinum are laminated in the order of SiN, SiO ₂ , Ta ₂ O ₅ , Pt, Ta ₂ O ₅ , SiO ₂ , and SiN.

  The wiring for taking the potential of the diode 7 and the electrodes 7Va and 7Vb are also formed in the same configuration as the resistance temperature detectors 3 and 5. However, the protective insulating film under the platinum constituting the wiring and the electrodes 7Va and 7Vb is removed in a part on the P-type region 7p + and the N-type region 7n +. Thereby, the P-type region 7p + and the wiring and electrode 7Va are electrically connected, and the N-type region 7n + and the wiring and electrode 7Vb are electrically connected.

An example of the semiconductor substrate 1 will be described.
The semiconductor substrate 1 is formed of, for example, a P-type silicon substrate having a crystal orientation (100). The depth of the cavity 1a is, for example, 50 to 300 μm. The cavity 1a is formed by, for example, an anisotropic wet etching method. As the etching solution, for example, a known anisotropic etching solution such as TMAH (tetramethylammonium hydroxide) aqueous solution, KOH (potassium hydroxide) aqueous solution, hydrazine aqueous solution (64 mol%, liquid temperature 90 to 110 ° C.) or the like is used. The

An example of the diode 7 will be described.
The diode 7 is a PN junction diode formed by a P-type region 7p + and an N-type region 7n. The diode 7 is formed by a normal semiconductor device manufacturing process such as an IC manufacturing process or an LSI manufacturing process. As an example, phosphorus is ion-implanted into a P-type silicon substrate 1 having a substrate resistance of 20 Ω · cm using a resist as a mask. After removing the resist, heat treatment is performed at 1150 ° C. to form an N-type region 7n.

  Arsenic ions are implanted using a resist as a mask in order to form an N-type region 7n + for ohmic connection with the metal wiring at the bottom of the contact hole. After removing the resist, boron is ion-implanted at a position overlapping the formation position of the N-type region 7n using the resist as a mask. After removing the resist, heat treatment at 950 ° C. is performed to activate the implanted ions to form the P-type region 7p + and the N-type region 7n +.

  FIG. 2 is a diagram for explaining the temperature characteristic of the forward resistance value of the PN junction diode. The horizontal axis indicates the temperature, and the vertical axis indicates the resistance value.

  The PN junction diode has a so-called negative temperature coefficient in which the resistance value decreases almost in proportion to the temperature. The forward current Id of an ideal PN junction diode can be expressed by the following formula (1).

Id = Is × A × (e ^{qVd / kT} −1) (1)
However, Is is a saturation current, A is an ideal constant, q is an elementary charge, Vd is a forward voltage, k is a Boltzmann coefficient, and T is an absolute temperature.

  In a PN junction diode manufactured in a normal semiconductor device manufacturing process, the temperature characteristic of the forward resistance value of the PN junction diode is not easily affected by variations in dimensions and the like. Therefore, in the plurality of thermal elements 10 having the same structure in which the diode 7 is formed, the variation in the forward resistance temperature coefficient of the diode 7 is small.

Next, an embodiment of a method for determining the resistance value temperature coefficient of the resistance temperature detector in the thermal element of the present invention will be described.
FIG. 3 is a flowchart for explaining this embodiment. The resistance value temperature coefficient determination method of the present invention may be implemented after assembling the thermal element into the atmosphere meter, or may be performed before assembling, for example, in a wafer state. In this embodiment, an example in which the wafer is implemented will be described. This embodiment will be described with reference to FIG.

(Step S11) With respect to one wafer on which one or more thermal elements 10 are formed, the forward resistance value of the diode 7 is measured using a thermostatic chamber. For the measurement, wiring and electrodes 7Va and 7Vb are used. As a result, the relationship between the temperature change and the forward resistance value change is obtained for the diode 7.

(Step S12) The temperature coefficient of the diode 7 is acquired based on the relationship between the temperature change of the obtained diode 7 and the forward resistance value change. The measurement using the thermostat is finished.

(Step S21) The resistance value of the second resistance temperature detector 5 and the diode for another wafer on which a thermal element having the same structure as that of the thermal element 10 formed on the wafer used in Step S11 is formed. A forward resistance value of 7 is measured. At this time, the current is supplied to the second resistance temperature detector 5 while changing the current within a predetermined range. Here, the range of the current value to be supplied includes, for example, zero. The supplied current value may be any number as long as it is two or more.

  For example, with respect to the resistance value of the second resistance temperature detector 5 and the resistance value of the diode 7, before supplying the current to the second resistance temperature detector 5 (zero supply current), a predetermined value is applied to the second resistance temperature detector 5. Measurement is performed at two points after the current is supplied and the second resistance temperature detector 5 is heated. As a result, information on the resistance value change of the second resistance temperature detector 5 and the resistance value change of the diode 7 is obtained. Note that the electrodes 5Ia and 5Ib, wiring, and electrodes 7Va and 7Vb are used for resistance value measurement.

(Step S22) Since the variation in the forward resistance temperature coefficient of the diode 7 is small in the plurality of thermal elements 10 having the same structure, the forward resistance of the diode 7 in this wafer and the diode 7 used in the above step S11 The value temperature coefficient can be considered the same. The temperature change of the diode 7 is calculated based on the resistance value temperature coefficient of the diode 7 obtained in step S12 and the resistance value change of the diode 7 obtained in step S21.

(Step S23) Since the diode 7 is disposed below the second resistance temperature detector 5, the temperature change of the diode 7 obtained in step S22 is regarded as the temperature change of the second resistance temperature detector 5. Can do. Based on the temperature change of the diode 7 and the resistance value change of the second resistance temperature detector 5, the resistance value temperature coefficient of the second resistance temperature detector 5 is calculated.

(Step S24) In the thermal element 10, the second resistance temperature detector 5 and the first resistance temperature detector 3 have the same resistance value temperature coefficient. Therefore, the resistance value temperature coefficient of the second resistance temperature detector 5 obtained in step S23 can be regarded as the resistance value temperature coefficient of the first resistance temperature detector 3. In this way, the resistance value temperature coefficient of the first resistance temperature detector 3 is determined.

Thus, in this embodiment, the resistance value temperature coefficient of the first resistance temperature detector 3 can be determined for a large number of the other wafers without using a thermostat. The resistance value temperature coefficient of the resistance temperature detector can be determined by simple measurement.

  In the thermal element 10 shown in FIG. 1, the wiring and the electrodes 7Va and 7Vb for taking the potential of the diode 7 are formed at the same time as the resistance temperature detectors 3 and 5, but take the potential of the diode 7. Therefore, the wiring and the electrode may be formed by a process provided separately from the process of forming the resistance temperature detectors 3 and 5.

  FIG. 4 is a schematic plan view and cross-sectional view for explaining another embodiment of the thermal element of the present invention. In FIG. 4, the cross-sectional view shows a cross section at the BB position in the plan view. Further, in FIG. 4, the same reference numerals are given to portions that perform the same function as in FIG. 1.

  In the thermal element 10 of this embodiment, the wiring and the electrodes 7Va and 7Vb are not formed in order to take the potential of the diode 7 as compared with the thermal element shown in FIG. Further, an interlayer insulating film 9 such as a BPSG (Boro-phosphosilicate glass) film is formed on the upper surface of the semiconductor substrate 1. The interlayer insulating film 9 has an opening 9a on the cavity 1a.

  In the first resistance temperature detector 3, portions not cross-linked on the cavity 1 a, that is, portions of the electrodes 3 Ia and 3 Ib and wiring and portions of the electrodes 3 Va and 3 Vb are covered with an interlayer insulating film 9. The second resistance temperature detector 5 is covered with an interlayer insulating film 9.

  A plurality of contact holes are formed at predetermined positions of the interlayer insulating film 9. The contact holes are formed on the electrodes 3Ia and 3Ib of the first resistance temperature detector 3, on the wiring and the electrode portions of the electrodes 3Va and 3Vb, on the electrodes 5Ia and 5Ib of the second resistance temperature detector 5, and on the wiring and the electrodes 5Va and 5Vb. It is formed on the electrode portion and on the P-type region 7p + and the N-type region 7n + of the diode 7.

  Wirings and electrodes made of a metal material are formed in the contact holes and on the interlayer insulating film 9. Electrodes 3Ia1 and 3Ib1 are formed corresponding to the electrodes 3Ia and 3Ib of the first resistance temperature detector 3. Electrodes 3Va1 and 3Vb1 are formed corresponding to the wiring and electrode portions of electrodes 3Va and 3Vb. Electrodes 5Ia1 and 5Ib1 are formed corresponding to the electrodes 5Ia and 5Ib of the second resistance temperature detector 5. Electrodes 5Va1 and 5Vb1 are formed corresponding to the electrode portions of the wiring and electrodes 5Va and 5Vb. A wiring and an electrode 7Va1 are formed corresponding to the P-type region 7p of the diode 7. Corresponding to the N-type region 7n + of the diode 7, a wiring and an electrode 7Vb1 are formed.

  A protective film (not shown) is formed on the interlayer insulating film 9. In the protective film, pad openings are formed on the electrodes 3Ia1, 3Ib1, 3Va1, 3Vb1, 5Ia1, 5Ib1, 5Va1, 5Vb1, and the wiring and electrodes 7Va1, 7Vb1. In addition, an opening corresponding to the opening 9a is also formed in the protective film.

The potential of the diode 7 is acquired through the wiring and the electrodes 7Va1 and 7Vb1. The potentials of the resistance temperature detectors 3 and 5 are acquired via the electrodes 3Ia1, 3Ib1, 3Va1, 3Vb1, 5Ia1, 5Ib1, 5Va1, and 5Vb1.
As described above, the wiring and the electrodes for taking the potential of the diode 7 may be formed by a process provided separately from the process of forming the resistance temperature detectors 3 and 5.

  The contact holes and the electrodes 5Va1 and 5Vb1 for taking the potential of the wiring of the second resistance temperature detector 5 and the electrodes 5Va and 5Vb may not be formed.

  As mentioned above, although the Example of this invention was described, the dimension, material, arrangement | positioning, shape, etc. which were shown by the said Example are examples, and this invention is not limited to the said Example. The present invention can be variously modified within the scope of the present invention described in the claims.

For example, in the thermal element 10, the cavity 1 a may be formed through the semiconductor substrate 1.
In the thermal element of the present invention, the semiconductor substrate is not limited to a P-type silicon substrate having a crystal orientation of (100), but may be another semiconductor substrate.

  The second resistance temperature detector 5 of the thermal element 10 includes wiring and electrodes 5Va and 5Vb. The first resistance temperature detector 3 and the second resistance temperature detector 5 have the same resistance temperature coefficient. If so, the wiring and the electrodes 5Va and 5Vb may not be formed.

  Further, the materials and structures of the first resistance temperature detector and the second resistance temperature detector in the thermal element of the present invention are the first resistance temperature detector 3 and the second resistance temperature detector 5 shown in the above embodiment. Any material and structure may be used as long as the material and structure function as a resistance temperature detector.

  Moreover, although the said Example about the determination method of the resistance value temperature coefficient of the resistance temperature detector in the thermal type | mold element of this invention uses the wafer in order to measure the forward direction resistance value temperature coefficient of the diode 7, The invention is not limited to this. The measurement of the forward resistance temperature coefficient of the diode may be performed in the state of a thermal element cut out from the wafer, or may be performed in the state of an atmosphere meter in which the thermal element is mounted. The resistance value of the second resistance temperature detector and the resistance value of the diode may be measured in the state of a thermal element cut out from the wafer, or in the state of an atmosphere meter in which the thermal element is mounted. It may be done.

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 1a Cavity part 3 1st resistance temperature detector 5 2nd resistance temperature detector 7 Diode 7p + P-type area | region 7n N-type area | region 10 Thermal element

Japanese Patent No. 2889909 JP 2010-278142 A Japanese Patent No. 4558647

Claims (4)

A first resistance temperature detector for detection arranged in a bridge on a cavity formed in a semiconductor substrate;
A second temperature measuring resistor for temperature coefficient measurement, which is disposed on the semiconductor substrate at a position different from the cavity and has the same resistance value temperature coefficient as that of the first resistance temperature detector;
A thermal element comprising: a diode formed of a P-type region and an N-type region formed in the semiconductor substrate below the second resistance temperature detector. The second resistance temperature detector has the same structure as the first resistance temperature detector,
The first temperature measuring resistor and the second temperature measuring resistor are formed at the same time in the same process, and are arranged at a distance such that the structure and the resistance temperature coefficient are the same. The thermal element described in 1.   The thermal element according to claim 1, wherein the wiring for taking the potential of the PN junction diode is formed of the same material at the same time and in the same process as the resistance temperature detector. Using the thermal element according to any one of claims 1 to 3,
In order to determine the resistance temperature coefficient of the first resistance temperature detector for a plurality of the thermal elements having the same structure,
A diode temperature coefficient measuring step of measuring a forward resistance value temperature coefficient of the diode of any one of the thermal elements;
Changes in the forward resistance value of the diode when the second resistance temperature detector is heated by supplying a current within a predetermined range to the second resistance temperature detector of the other thermal element, and A resistance value measuring step for measuring a resistance value change of the second resistance temperature detector;
The second resistance temperature detector based on a resistance value change of the second resistance temperature detector, a forward resistance value change of the diode, and a temperature change of the second resistance temperature detector that can be calculated by a temperature coefficient of the diode. A temperature measuring resistor temperature coefficient determining step of calculating a resistance value temperature coefficient of the body and using the temperature coefficient as a resistance value temperature coefficient of the first resistance temperature detector. How to determine the coefficient.

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